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Diffusion-weighted imaging (DWI) is a well-established MRI sequence for diagnosing early stroke and provides therapeutic implications. However, DWI yields pertinent information in various other brain pathologies and helps establish a specific diagnosis and management of other central nervous system disorders. Some of these conditions can present with acute changes in neurological status and mimic stroke. This review will focus briefly on diffusion imaging techniques, followed by a more comprehensive description of the utility of DWI in common neurological entities beyond stroke.

Malignant myoepithelioma of the scrotum is extremely rare. We report the case of a 51-year-old man with malignant myoepithelioma of the scrotum, wherein computed tomography and magnetic resonance imaging revealed a lobulated soft tissue mass with calcification, cystic component, and solid component with gradual contrast enhancement on dynamic contrast-enhanced scans. The patient presented with scrotal induration, and there was no elevation of tumor markers and no evidence of a metastatic lesion on computed tomography and magnetic resonance imaging. Histopathological examination of the resected scrotal specimen confirmed a well-circumscribed solid tumor with septa, a small area of hemorrhage, and necrosis. The subsequent diagnosis was malignant myoepithelioma of the scrotum. This case shows that scrotal malignant myoepithelioma might appear as a well-defined lobulated mass with cystic regions. We conjecture that the enhancement pattern and apparent diffusion coefficient values can be potential markers for scrotal myoepithelial tumors.

Purpose Manual delineation of a rectal tumor on a volumetric image is time‐consuming and subjective. Deep learning has been used to segment rectal tumors automatically on T2‐weighted images, but automatic segmentation on diffusion‐weighted imaging is challenged by noise, artifact, and low resolution. In this study, a volumetric U‐shaped neural network (U‐Net) is proposed to automatically segment rectal tumors on diffusion‐weighted images. Methods Three hundred patients of locally advanced rectal cancer were enrolled in this study and divided into a training group, a validation group, and a test group. The region of rectal tumor was delineated on the diffusion‐weighted images by experienced radiologists as the ground truth. A U‐Net was designed with a volumetric input of the diffusion‐weighted images and an output of segmentation with the same size. A semi‐automatic segmentation method was used for comparison by manually choosing a threshold of gray level and automatically selecting the largest connected region. Dice similarity coefficient (DSC) was calculated to evaluate the methods. Results On the test group, deep learning method (DSC = 0.675 ± 0.144, median DSC is 0.702, maximum DSC is 0.893, and minimum DSC is 0.297) showed higher segmentation accuracy than the semi‐automatic method (DSC = 0.614 ± 0.225, median DSC is 0.685, maximum DSC is 0.869, and minimum DSC is 0.047). Paired t‐test shows significant difference (T = 2.160, p = 0.035) in DSC between the deep learning method and the semi‐automatic method in the test group. Conclusion Volumetric U‐Net can automatically segment rectal tumor region on DWI images of locally advanced rectal cancer.

Chordomas are relatively rare malignant tumors derived from embryonic notochord remnants. Most intracranial chordomas show extradural extension and cause bone erosion. However, a small percentage of these tumors are exclusively intradural and tend to show less aggressive features, although local recurrence and metastatic spread have been described. Intradural chordomas with imaging features similar to epidermoid cysts are exceedingly rare. We describe the case of a nonenhancing and nondestructive intradural prepontine chordoma showing restricted diffusion on magnetic resonance imaging on a 44-year-old man who presented with acute-onset vertigo and vomiting. Subtotal resection of the lesion was performed followed by adjuvant radiation therapy. Histopathological examination revealed a chordoma. This case report highlights the need to include intradural chordomas in the differential diagnosis of a nonenhancing and nondestructive prepontine intradural lesion demonstrating restricted diffusion. Gross total resection, adjuvant radiation therapy in cases of macro/microscopical residual disease and regular follow-up imaging assessment are warranted due to the possibility of local recurrence and metastatic dissemination.

BACKGROUND The accuracy of discriminating pT3a from pT3b-c rectal cancer using high-resolution magnetic resonance imaging (MRI) remains unsatisfactory, although texture analysis (TA) could improve such discrimination. AIM To investigate the value of TA on apparent diffusion coefficient (ADC) maps in differentiating pT3a rectal adenocarcinomas from pT3b-c tumors. METHODS This was a case-control study of 59 patients with pT3 rectal adenocarcinoma, who underwent diffusion-weighted imaging (DWI) between October 2016 and December 2018. The inclusion criteria were: (1) Proven pT3 rectal adenocarcinoma; (2) Primary MRI including high-resolution T2-weighted image (T2WI) and DWI; and (3) Availability of pathological reports for surgical specimens. The exclusion criteria were: (1) Poor image quality; (2) Preoperative chemoradiation therapy; and (3) A different pathological type. First-order (ADC values, skewness, kurtosis, and uniformity) and second-order (energy, entropy, inertia, and correlation) texture features were derived from whole-lesion ADC maps. Receiver operating characteristic curves were used to determine the diagnostic value for pT3b-c tumors. RESULTS The final study population consisted of 59 patients (34 men and 25 women), with a median age of 66 years (range, 41-85 years). Thirty patients had pT3a, 24 had pT3b, and five had pT3c. Among the ADC first-order textural differences between pT3a and pT3b-c rectal adenocarcinomas, only skewness was significantly lower in the pT3a tumors than in pT3b-c tumors. Among the ADC second-order textural differences, energy and entropy were significantly different between pT3a and pT3b-c rectal adenocarcinomas. For differentiating pT3a rectal adenocarcinomas from pT3b-c tumors, the areas under the curves (AUCs) of skewness, energy, and entropy were 0.686, 0.657, and 0.747, respectively. Logistic regression analysis of all three features yielded a greater AUC (0.775) in differentiating pT3a rectal adenocarcinomas from pT3b-c tumors (69.0% sensitivity and 83.3% specificity). CONCLUSION TA features derived from ADC maps might potentially differentiate pT3a rectal adenocarcinomas from pT3b-c tumors.

Objective: Normal diffusion-weighted imaging (DWI) during the acute symptomatic phase of an ischemic stroke is a rare, but a well-known phenomenon. The exact rate and the clinical correlates of this phenomenon are not satisfactorily elucidated. Materials and Methods: Consecutive patients who were hospitalized with the diagnosis of acute ischemic stroke in the last 10 years and who had DWI (with a bmax of 1000 s/mm2) in the first 12 hours were included. A systematic review of published DWI-negative stroke cases and case series was performed. Alternate diagnoses including transient ischemic attack or stroke mimics such as seizure, migraine, functional disorders, and post-stroke recrudescence were excluded. Results: The diagnosis of DWI-negative stroke syndrome was made in 20 (1.3%) of 1.506 patients hospitalized in Hacettepe Hospitals. A literature search disclosed another 535 (6.6%) DWI-negative strokes out of 8.101 cases. A total of 115, identified in case reports and cohort (n=19) articles, were combined with our cases to delineate further characteristics of DWI-negative clinical stroke syndromes. DWI-negative syndromes (n=135) were “brainstem mini-strokes” (31.1%), “cortical small embolic infarcts” (5.2%), “pure penumbral stroke” (normal DWI with magnetic resonance perfusion deficit) (34.8%); “aborted stroke” (early and fully recanalized stroke, only diagnosable in patients with documented acute vessel occlusion) (5.2%); and “miscellaneous” (23.7%). Corresponding clinical stroke syndromes include partial hemispheric deficits (36.1%), focal cortical syndromes (4.3%), caudal brainstem syndromes (9.3%), acute isolated vertigo (9.3%), vertigo-plus syndromes (10.1%), ocular syndromes (7.4%), movement disorders (1.9%), typical lacunar syndromes (11.1%), and atypical lacunar syndromes such as ataxia ± dysatrhria (9.3%). Conclusion: In clinical practice of acute ischemic stroke, early DWI imaging can be negative in various clinical syndromes. Imaging repetition is necessary for the diagnosis and management plan of these patients.

Yong-Ren Wang, Zhao-Sheng Li, Wei Huang, Hui-Qiang Yang, Bo Gao, Yu-Ting Chen Department of Radiology, Chinese Medical Hospital of Yiwu, Yiwu, 322000, People’s Republic of ChinaCorrespondence: Yong-Ren WangDepartment of Radiology, Chinese Medical Hospital of Yiwu, No. 266 Xuefeng West Road, Yiwu, 322000, People’s Republic of ChinaTel +86 579 85439171Fax +86 579 85527330Email wangry65398@163.comBackground: The aim of this study was to discuss the value of susceptibility-weighted imaging (SWI) in evaluating the ischemic penumbra of patients with acute cerebral ischemic stroke.Methods: Data were collected from 52 patients with acute cerebral ischemic stroke upon clinical diagnosis and routine examinations of magnetic resonance imaging (MRI), including SWI, diffusion-weighted imaging (DWI), and perfusion-weighted imaging (PWI) within 72 hours after onset in this retrospective study. The methods also included fusing the DWI and SWI images and calculating the volume of anomaly extension of DWI and PWI-MTT (mean transit time) using semi-automatic analysis software. The SWI-DWI and PWI-DWI mismatches were interpreted, and the statistical analysis was completed.Results: The two physicians found that the ischemic penumbra consistency is high throughout the SWI-DWI and PWI-DWI mismatches, without a significant difference (P > 0.05).Conclusion: SWI-DWI mismatch can prevent the injection of contrast agents and make an accurate diagnosis of acute stroke ischemic penumbra, which helps guide the selection of the clinical therapeutic plan.Keywords: ischemic penumbra, diffusion-weighted imaging, susceptibility-weighted imaging, perfusion-weighted imaging

Objectives: The purpose of this study was to assess the accuracy of contrast-enhanced magnetic resonance imaging and diffusion-weighted imaging in distinguishing benign from malignant non-mass-like breast lesions. Methods: 103 lesions showing non-mass-like enhancement in 100 consecutive patients were analyzed. Distribution, internal enhancement patterns, and contrast kinetic curve patterns were classified according to the BI-RADS lexicon. Apparent diffusion coefficient (ADC) values were obtained from manually placed regions of interest (ROIs) on diffusion-weighted images. The optimal ADC value threshold for the distinction between benign and malignant lesions was determined by ROC analysis. Univariate and multivariate analyses were performed to identify independent predictors of malignancy, and the probability of malignancy was calculated for various combinations of findings. Histological diagnosis obtained by means of core needle biopsy was used as gold standard. Results: According to the univariate and multivariate analysis, odds ratios for malignancy were significantly elevated for clumped or clustered ring internal enhancement and low ADC values (p < 0.001), whereas distribution patterns and contrast kinetic patterns were not significantly correlated with benignity or malignancy. In non-mass lesions with homogeneous or heterogeneous internal enhancement and ADC values greater than 1.26×10 -3 mm 2 /s, no malignancy was detected, while all other combinations of findings had a probability of malignancy ranging from 22.2 to 76.6%. Conclusions: A combination of BI-RADS descriptors of internal enhancement and ADC values is useful for the differential diagnosis of lesions showing non-mass enhancement. Lesions with homogeneous or heterogeneous enhancement and high ADC can be followed up, while all other lesions should be biopsied. Doi: 10.28991/SciMedJ-2021-0302-1 Full Text: PDF

Purpose Reperfusion therapy enables effective treatment of ischemic stroke presenting within 4-6 hours. However, tissue progression from ischemia to infarction is variable, and some patients benefit from treatment up until 24 hours. Improved imaging techniques are needed to identify these patients. Here, it was hypothesized that time dependence in diffusion MRI may predict tissue outcome in ischemic stroke. Methods Diffusion MRI data were acquired with multiple diffusion times in five non-reperfused patients at 2, 9, and 100 days after stroke onset. Maps of "rate of kurtosis change" (k), mean kurtosis, ADC, and fractional anisotropy were derived. The ADC maps defined lesions, normal-appearing tissue, and the lesion tissue that would either be infarcted or remain viable by day 100. Diffusion parameters were compared (1) between lesions and normal-appearing tissue, and (2) between lesion tissue that would be infarcted or remain viable. Results Positive values of k were observed within stroke lesions on day 2 (P = .001) and on day 9 (P = .023), indicating diffusional exchange. On day 100, high ADC values indicated infarction of 50 ± 20% of the lesion volumes. Tissue infarction was predicted by high k values both on day 2 (P = .026) and on day 9 (P = .046), by low mean kurtosis values on day 2 (P = .043), and by low fractional anisotropy values on day 9 (P = .029), but not by low ADC values. Conclusions Diffusion time dependence predicted tissue outcome in ischemic stroke more accurately than the ADC, and may be useful for predicting reperfusion benefit.

Background/aim To evaluate diagnostic efficacy of the apparent diffusion coefficient measurements from tumor (ADCt) and tumor circumference hyperintensities (ADCtch) in different types of malignant intra-axial brain tumors. Materials and methods Between April 2013 and June 2017 , 125 patients (52 females (41.6%) and 73 males (58.4%); mean age: 53 years, age range: 14-81 years), who underwent diffusion-weighted imaging (DWI) with intracranial mass, were retrospectively evaluated. The mean ADCt and ADCtch values and ratios were measured. Results Of the 125 patients, 22 (17.6%) had a low-grade glioma (LGG), 55 (44%) had a high-grade glioma (HGG), 32 (25.6%) had metastasis, and 16 (12.8%) had lymphoma diagnosis. There was a statistically significant difference in LGG and HGG in terms of mean ADCt and mean ADCtch values, and ratios. ADCtch values and ratios showed a statistically significant difference in the differentiation of HGG and metastasis and in the differentiation of HGG and lymphoma. According to ROC curve analysis, a cut-off value of 1.49 × 10−3 mm2/s for the mean ADCtch value generated the best combination of 70% sensitivity and 71% specificity for differentiation of HGGs and metastasis. The mean ADCtch value had the highest statistical predictive value for differentiation of HGGs and lymphoma with a sensitivity of 78% and a specificity of 76% for the optimal cut-off value of 0.82 × 10ˉ3 mm²/s. Conclusion The mean ADCt ratio allowed reliable differentiation of LGG and high grade brain tumors, including HGGs, metastases, and lymphoma. The mean ADCtch might be a better imaging biomarker in the differentiation of HHG from metastasis and lymphoma.

Purpose: This study aims to evaluate the incidence of clinically silent embolic cerebral infarctions and associated risk factors following diagnostic cerebral angiography with diffusion-weighted imaging (DWI). Material and methods: A total of 71 cerebral digital subtraction angiograms (42 male, 29 female, average age: 56.0 ± 15.0) obtained using nonionic contrast material were prospectively evaluated. To assess embolic events, before and after (1-3 days) angiography, DWI was performed. The risk factors for embolic ischemic brain changes such as the patient's age and sex, atherosclerotic vessel wall disease, type of indication for catheter angiography, the number and size of the catheters, anatomic variants, selective/nonselective catheterization, contrast media volume, and time of procedure were determined. Fisher's exact tests and Student t-tests were used for the statistical analyses of outcomes. Results: Thirteen new silent ischemic lesions were identified in 7 out of 71 patients who underwent diagnostic cerebral angiography. Embolic cerebral lesions were often 6-10mm in diameter. According to the findings in this study, there was a strong correlation between diffusion abnormality and patient age, which was considered risk factors (p < 0.05). However, there were no significant correlations between other risk factors and the lesions’ appearance (p > 0.05). Conclusions: In elderly patients, the angiographic procedures should be performed meticulously and DWI in all patients obtained routinely, even if the regular neurological examination shows they are healthy. In this way, the presence of microemboli and clinical results can be evaluated.

Background: To date, there are inconsistent data about relationships between diffusion-weighted imaging (DWI) and tumor grading/microvascular invasion (MVI) in hepatocellular carcinoma (HCC). Our purpose was to systematize the reported results regarding the role of DWI in prediction of tumor grading/MVI in HCC. Method: MEDLINE library, Scopus, and Embase data bases were screened up to December 2019. Overall, 29 studies with 2,715 tumors were included into the analysis. There were 20 studies regarding DWI and tumor grading, 8 studies about DWI and MVI, and 1 study investigated DWI, tumor grading, and MVI in HCC. Results: In 21 studies (1,799 tumors), mean apparent diffusion coefficient (ADC) values (ADCmean) were used for distinguishing HCCs. ADCmean of G1–3 lesions overlapped significantly. In 4 studies (461 lesions), minimum ADC (ADCmin) was used. ADCmin values in G1/2 lesions were over 0.80 × 10−3 mm2/s and in G3 tumors below 0.80 × 10−3 mm2/s. In 4 studies (241 tumors), true diffusion (D) was reported. A significant overlapping of D values between G1, G2, and G3 groups was found. ADCmean and MVI were analyzed in 9 studies (1,059 HCCs). ADCmean values of MIV+/MVI− lesions overlapped significantly. ADCmin was used in 4 studies (672 lesions). ADCmin values of MVI+ tumors were in the area under 1.00 × 10−3 mm2/s. In 3 studies (227 tumors), D was used. Also, D values of MVI+ lesions were predominantly in the area under 1.00 × 10−3 mm2/s. Conclusion: ADCmin reflects tumor grading, and ADCmin and D predict MVI in HCC. Therefore, these DWI parameters should be estimated for every HCC lesion for pretreatment tumor stratification. ADCmean cannot predict tumor grading/MVI in HCC.

Non-small cell lung cancer (NSCLC), a commonly diagnosed lung cancer, is characterized by a high incidence of metastatic spread to the brain, which adversely impacts prognosis. The present study aimed to assess the value of combined dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in predicting the treatment outcomes of whole-brain radiotherapy (WBRT) and gefitinib in brain metastases from non-small cell lung cancer (NSCLC) from the perspectives of response rate and short- and long-term efficacy. These results suggested that the indicators measured by DCE-MRI combined with DWI can be used as key imaging-derived markers that predicted the efficacy of WBRT combined with gefitinib in NSCLC patients with brain metastases. Specifically, patients with higher ΔADCmid and ΔADCpost values showed better treatment outcomes. ROC curve analysis indicated ADCpost, ΔADCpost, ΔADCpost (%), and tumor regression rate as the best predictors of efficacy of WBRT combined with gefitinib in these patients. The short-term and long-term effects noted were also significant. Taken together, the findings of this study reveal that tumor regression rate, ADCpost, ΔADCpost, and ΔADCpost (%) can be used as important imaging indicators that predict the therapeutic effect of WBRT combined with gefitinib in NSCLC patients with brain metastases.

BACKGROUND Reactive lymphoid hyperplasia (RLH) of the liver is a rare liver lesion. It is considered difficult to differentiate radiologically from hepatocellular carcinoma, metastatic liver tumor and other pathologies. CASE SUMMARY A 54-year-old woman presented to our hospital with RLH of the liver. The patient had a diagnosis of metastatic carcinoma of the liver from an unknown origin and subsequently underwent partial hepatectomy. However, histopathological analysis revealed RLH. The lesion showed perinodular enhancement in the arterial phase on contrast-enhanced computed tomography and magnetic resonance imaging. On diffusion-weighted imaging (DWI), we encountered linear hyperintensity along the portal tract consecutive to the liver lesion, which is a new characteristic radiologic finding. This finding corresponded to the lymphoid cell infiltration of the portal tract. Furthermore, there was strongly restricted diffusion on the apparent diffusion coefficient map. We used these characteristic radiologic findings to diagnose the lesion as a lymphoproliferative disease. CONCLUSION The linear hyperintensity consecutive to the liver lesion on DWI provided additional valuable diagnostic information.

BACKGROUND The activity staging of Crohn’s disease (CD) in the terminal ileum is critical in developing an accurate clinical treatment plan. The activity of terminal ileum CD is associated with the microcirculation of involved bowel walls. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) can reflect perfusion and permeability of bowel walls by providing microcirculation information. As such, we hypothesize that DCE-MRI and DWI parameters can assess terminal ileum CD, thereby providing an opportunity to stage CD activity. AIM To evaluate the value of DCE-MRI and DWI in assessing activity of terminal ileum CD. METHODS Forty-eight patients with CD who underwent DCE-MRI and DWI were enrolled. The patients’ activity was graded as remission, mild and moderate-severe. The transfer constant (Ktrans), wash-out constant (Kep), and extravascular extracellular volume fraction (Ve) were calculated from DCE-MRI and the apparent diffusion coefficient (ADC) was obtained from DWI. Magnetic Resonance Index of Activity (MaRIA) was calculated from magnetic resonance enterography. Differences in these quantitative parameters were compared between normal ileal loop (NIL) and inflamed terminal ileum (ITI) and among different activity grades. The correlations between these parameters, MaRIA, the Crohn’s Disease Activity Index (CDAI), and Crohn’s Disease Endoscopic Index of Severity (CDEIS) were examined. Receiver operating characteristic curve analyses were used to determine the diagnostic performance of these parameters in differentiating between CD activity levels. RESULTS Higher Ktrans (0.07 ± 0.04 vs 0.01 ± 0.01), Kep (0.24 ± 0.11 vs 0.15 ± 0.05) and Ve (0.27 ± 0.07 vs 0.08 ± 0.03), but lower ADC (1.41 ± 0.26 vs 2.41 ± 0.30) values were found in ITI than in NIL (all P < 0.001). The Ktrans, Kep, Ve and MaRIA increased with disease activity, whereas the ADC decreased (all P < 0.001). The Ktrans, Kep, Ve and MaRIA showed positive correlations with the CDAI (r = 0.866 for Ktrans, 0.870 for Kep, 0.858 for Ve, 0.890 for MaRIA, all P < 0.001) and CDEIS (r = 0.563 for Ktrans, 0.567 for Kep, 0.571 for Ve, 0.842 for MaRIA, all P < 0.001), while the ADC showed negative correlations with the CDAI (r = -0.857, P < 0.001) and CDEIS (r = -0.536, P < 0.001). The areas under the curve (AUC) for the Ktrans, Kep, Ve, ADC and MaRIA values ranged from 0.68 to 0.91 for differentiating inactive CD (CD remission) from active CD (mild to severe CD). The AUC when combining the Ktrans, Kep and Ve was 0.80, while combining DCE-MRI parameters and ADC values yielded the highest AUC of 0.95. CONCLUSION DCE-MRI and DWI parameters all serve as measures to stage CD activity. When they are combined, the assessment performance is improved and better than MaRIA.

Background Manual region-of-interest analysis of putaminal and middle cerebellar peduncle diffusivity distinguishes patients with multiple system atrophy (MSA) and Parkinson's disease (PD) with high diagnostic accuracy. However, a recent meta-analysis found substantial between-study heterogeneity of diagnostic accuracy due to the lack of harmonized imaging protocols and standardized analyses pipelines. Objective Evaluation of diagnostic accuracy of observer-independent analysis of microstructural integrity as measured by diffusion-tensor imaging in patients with MSA and PD. Methods A total of 29 patients with MSA and 19 patients with PD (matched for age, gender, and disease duration) with 3 years of follow-up were investigated with diffusion-tensor imaging and T1-weighted magnetic resonance imaging. Automated localization of relevant brain regions was obtained, and mean diffusivity and fractional anisotropy values were averaged within the regions of interest. The classification was performed using a C5.0 hierachical decision tree algorithm. Results Mean diffusivity of the middle cerebellar peduncle and cerebellar gray and white matter compartment as well as the putamen were significantly increased in patients with MSA and showed superior effect sizes compared to the volumetric analysis of these regions. A classifier model identified mean diffusivity of the middle cerebellar peduncle and putamen as the most predictive parameters. Cross-validation of the classification model yields a Cohen's κ and overall diagnostic accuracy of 0.823 and 0.914, respectively. Conclusion Analysis of microstructural integrity within the middle cerebellar peduncle and putamen yielded a superior effect size compared to the volumetric measures, resulting in excellent diagnostic accuracy to discriminate patients with MSA from PD in the early to moderate disease stages. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC. on behalf of International Parkinson and Movement Disorder Society.

Introduction. Mediastinal lymphadenopathy can be caused by a wide range of benign and malignant states. Determination of the genesis of lymphadenopathy is crucial for treatment planning and prognosis of the disease.The purpose of the studywas to evaluate the diagnostic accuracy of diffusion weighted imaging (DWI) with apparent diffusion coefficient (ADC) measurements in differentiating malignant versus benign mediastinal lymphadenopathy.Material and Methods. 48 consecutive patients with at least one enlarged mediastinal lymph node revealed on CT-scans were examined on 1,5 T MR-machine with conventional images and respiratory-triggered DWI. In all patients one of the biggest solid lymph nodes was selected for ADC measurements and mean ADCs of each node were recorded. ADCs were correlated with the results of complete diagnostic work-up (including histopathological diagnosis in 41 patients) and follow-up CT. Statistics included Student’s t-test, Mann-Whitney U-test and ROC-curve analysis.Results. 27 lymph nodes were classified as malignant (metastases, lymphoma) and 21 lymph nodes were classified as benign (sarcoidosis, reactive hyperplasia, tuberculosis). Mean ADC of malignant lymph nodes (1,02 ± 0,29×10−3 mm2/s) was significantly lower than that of benign lymph nodes (1,57 ± 0,32×10−3 mm2/s), pConclusion. DWI is a promising technique in chest pathology. DWI with ADC measurements could be used as a good complementary tool in the diagnostic work-up of patients with mediastinal lymphadenopathy.

Supplemental Digital Content is available in the text., Objective To provide a systematic review regarding the diagnostic performance of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) and diffusion-weighted imaging (DWI) compared to 18F-FDG PET/computed tomography (CT) focused on nodal and distant staging in breast cancer patients. Methods The PubMed and Embase databases were searched for relevant publications until April 2020. Two independent reviewers searched for eligible articles based on predefined in- and exclusion criteria, assessed quality and extracted data. Results Eleven eligible studies were selected from 561 publications identified by the search. In seven studies, PET/CT was compared with PET/MRI, and in five, PET/CT with DWI. Significantly higher sensitivity for PET/MRI compared to PET/CT in a lesion-based analysis was reported for all lesions together (77% versus 89%) in one study, osseous metastases (69–99% versus 92–98%) in two studies and hepatic metastases (70–75% versus 80–100%) in one study. Moreover, PET/MRI revealed a significantly higher amount of osseous metastases (90 versus 141) than PET/CT. PET/CT is associated with a statistically higher specificity than PET/MRI in the lesion detection of all lesions together (98% versus 96%) and of osseous metastases (100% versus 95%), both in one study. None of the reviewed studies reported significant differences between PET/CT and DWI for any of the evaluated sites. There is a trend toward higher specificity for PET/CT. Conclusion In general, there is a trend toward higher sensitivity and lower specificity of PET/MRI when compared to PET/CT. Results on the diagnostic performance of DWI are conflicting. Rather than evaluating it separate, it seems to have complementary value when combined with other MR sequences.

Study Design: Observational study.Purpose: To evaluate healthy volunteers and patients with spinal canal lesions using apparent diffusion coefficient (ADC) maps with diffusion-weighted imaging.Overview of Literature: Decompression surgery for lumbar spinal stenosis (LSS) is selected on the basis of subjective assessment and cross-sectional magnetic resonance imaging (MRI). However, there is no objective standard for this procedure.Methods: We performed 3T MRI in 10 healthy volunteers and 13 patients with LSS. The ADC values in the spinal canal were evaluated at 46 vertebrae (L4/5 and L5/S1 for each participant), and the reduced and conventional fields of view were compared.Results: The ADC values were 2.72±0.12 at L4/5 in healthy volunteers, 2.76±0.19 at L5/S1 in healthy volunteers, 1.77±0.58 at L4/5 in patients with LSS, and 2.35±0.29 at L5/S1 in patients with LSS. The ADC value at L4/5 in patients with LSS was significantly lower than that at L5/S1 in patients with LSS and that at L4/5 and L5/S1 in healthy volunteers (p p

Guang-Zhi Wang,1,2 Ling-Fei Guo,3 Gui-Hua Gao,3 Yao Li,4 Xi-Zhen Wang,2 Zhen-Guo Yuan1,3 1Cheeloo College of Medicine, Shandong University, Jinan 250021, People’s Republic of China; 2Department of Medical Imaging Center, Affiliated Hospital, Weifang Medical University, Weifang 261053, People’s Republic of China; 3Department of MRI, Shandong Medical Imaging Research Institute, Cheeloo College of Medicine, Shandong University, Jinan 250021, People’s Republic of China; 4Zhucheng People’s Hospital Affiliated to Weifang Medical University, Weifang 262200, People’s Republic of ChinaCorrespondence: Zhen-Guo YuanShandong Medical Imaging Research Institute, Cheeloo College of Medicine, Shandong University, No. 324, Jing-wu road, Huaiyin District, Jinan 250021, People’s Republic of ChinaEmail yuanzg88@126.comPurpose: To investigate the diagnostic efficacy of diffusion kurtosis imaging (DKI) and conventional diffusion-weighted imaging (DWI) for pathological grading.Methods: From December 2015 to January 2017, consecutive patients suspected of having hepatocellular carcinoma (HCC) without prior treatment were prospectively enrolled in this study. MRI examinations were performed before surgical treatment. HCC patients confirmed by surgical pathology were included in the study. The mean diffusivity (MD) values, mean kurtosis (MK) values, and apparent diffusion coefficient (ADC) were calculated. The differences and correlations of these parameters among different pathological grades were analyzed. The diagnostic efficiency of DKI and DWI for predicting high-grade HCC was evaluated by receiver operating characteristic (ROC) curves. Logistic regression analyses were used to evaluate the predictive factors for pathological grade.Results: A total of 128 patients (79 males and 49 females, age: 56.9± 10.9 years, range, 32– 80) with primary HCC were included: grade I: 22 (17.2%) patients, grade II: 37 (28.9%) patients, grade III: 43 (33.6%) patients, grade IV: 26 (20.3%) patients. The MK values of stage I, II, III, and IV were 0.86± 0.13, 1.06± 0.11, 1.27± 0.17, and 1.57± 0.13, respectively. The MK values were significantly higher in the high-grade group than in the low-grade group and were positively correlated with pathological grade (rho =0.7417, P< 0.001). The MK value demonstrated a larger area under the curve (AUC), with a value of 0.93 than the MD value, which had an AUC of 0.815 (P< 0.001), and ADC, which had an AUC of 0.662 (P=0.01). The MK value (> 1.19), ADC (≤ 1.29× 10– 3 mm2/s), and HBV (+) were independent predictors for the pathological grade of HCCs.Conclusion: The MK values derived from DKI and the ADC values obtained from traditional DWI were more valuable than the MD values in predicting the histological grade of HCCs and could potentially guide clinical treatment before surgery.Keywords: hepatocellular carcinoma, pathology, diffusion kurtosis imaging, diffusion-weighted imaging, predictor

Background: Hereditary diffuse leukoencephalopathy with spheroids (HDLS), first described in 1984 is a rare disorder. Generally, it presents at adulthood with dementia, motor impairment, extrapyramidal abnormalities, and epilepsy. Definitive diagnosis is made by brain biopsy. Neuroimaging studies have revealed confluent white matter lesions predominantly in the frontal lobes, corpus callosum, and corticospinal tracts on conventional magnetic resonance imaging. Only a few reports showed diffusion restriction in the cerebral white matter; furthermore, rarer reports emphasized persistent foci of diffusion restriction as a diagnostic imaging marker. Objective: Herein, we have aimed to illustrate the first biopsy-proven Turkish HDLS pedigree consisting of 18 persons in 3 generations which contained 4 affected individuals. Materials and Methods: Four individuals in the pedigree of HDLS [two affected patients (patient III-1 and patient III-2) and two unaffected individuals (patient II-4 and patient III-5)] were investigated with conventional MRI and Diffusion-weighted imaging (DWI) using 1.5 Tesla (T) scanner. All four individuals were evaluated via neurological examinations and Mini-Mental State Examination. Brain biopsy study was performed on patient III-2. Finally, an extensive literature review involving pathology investigations and neuroimaging studies of HDLS patients was conducted. Results: DWIs of two investigated patients showed deep white matter lesions with persistent diffusion restriction. Computed tomography imaging showed punctate mineralization in the lesions. Biopsy specimens of patient III-2 demonstrated axonal spheroids which were typical for HDLS. Conclusions: Via the presentation of our pedigree and literature review, we suggest HDSL as a first-line differential diagnosis in patients with undiagnosed adult-onset familial leukoencephalopathy, in particular, those with MRI lesions of frontal white matter and centrum semiovale associated with foci of diffusion restriction and mineralization. Finally, we think that the persistence of the diffusion restriction in deep white matter lesions should be kept in mind as a crucial neuroimaging sign for HDLS.

Background To measure regional brain microvascular and microstructural changes in childhood-onset SLE (cSLE) using diffusion-weighted imaging (DWI) at multiple b values and investigate relationships of those measures with neurocognitive function and disease activity. Methods In this cross-sectional, case-control study, vascular volume fraction, effective diffusion, parenchymal diffusion, and blood flow parameters were regionally compared in cSLE patients and matched healthy controls. These markers of microvascular and microstructural integrity were derived by diffusion-weighted brain MRI and intravoxel incoherent motion (IVIM) modeling. Formal neurocognitive testing was completed focused on the domains of attention, visuoconstructional ability, working memory, and psychomotor speed. Test scores and measures of disease severity were regressed against regional microvascular integrity parameters among cSLE patients. Results Formal cognitive testing confirmed normal cognitive ability among all cSLE patients included in the analysis (n = 11). Nevertheless, reduction in blood volume fraction coincided with increased effective diffusion and flow parameters in cSLE patients vs. controls in posterior brain regions including the cuneus and precuneus. Regional microvascular measures correlated (|r| = 0.54–0.66) with neuropsychiatric scores and disease activity among cSLE patients. Conclusions There is imaging evidence, using IVIM, of degraded microvascular integrity in cSLE patients with normal cognitive ability. The observed regional changes correspond with posterior vascular border zones. These outcomes appear consistent with regional gray matter volume loss previously observed in cSLE patients with overt neurocognitive deficits, supporting the notion that adverse vascular changes precede loss of cognitive ability in cSLE. Longitudinal studies are needed to confirm the findings of this initial study.

Purpose Diffusion-weighted imaging (DWI) plays an important role in the preoperative assessment of gliomas; however, the diagnostic performance of histogram-derived parameters from mono-, bi-, and stretched-exponential DWI models in the grading of gliomas has not been fully investigated. Therefore, we compared these models’ ability to differentiate between high-grade and low-grade gliomas. Methods This retrospective study included 22 patients with diffuse gliomas (age, 23–74 years; 12 males; 11 high-grade and 11 low-grade gliomas) who underwent preoperative 3 T-magnetic resonance imaging from October 2014 to August 2019. The apparent diffusion coefficient was calculated from the mono-exponential model. Using 13 b-values, the true-diffusion coefficient, pseudo-diffusion coefficient, and perfusion fraction were obtained from the bi-exponential model, and the distributed-diffusion coefficient and heterogeneity index were obtained from the stretched-exponential model. Region-of-interests were drawn on each imaging parameter map for subsequent histogram analyses. Results The skewness of the apparent diffusion, true-diffusion, and distributed-diffusion coefficients was significantly higher in high-grade than in low-grade gliomas (0.67 ± 0.67 vs. − 0.18 ± 0.63, 0.68 ± 0.74 vs. − 0.08 ± 0.66, 0.63 ± 0.72 vs. − 0.15 ± 0.73; P = 0.0066, 0.0192, and 0.0128, respectively). The 10th percentile of the heterogeneity index was significantly lower (0.77 ± 0.08 vs. 0.88 ± 0.04; P = 0.0004), and the 90th percentile of the perfusion fraction was significantly higher (12.64 ± 3.44 vs. 7.14 ± 1.70%: P Conclusion The bi-exponential model exhibited the best diagnostic performance for differentiating high-grade from low-grade gliomas.

We developed a Monte Carlo simulator for diffusion-weighted imaging sequences which displays the motion of water molecules and computes the dynamic phase dispersion due to the applied motion probing gradients. This simulator can be used to validate the analytical equations of diffusion models and understand their limitations due to their approximations. Here, we introduce the software and some specific use cases. The software can be downloaded from the following website: https://www.nirs.qst.go.jp/amr_diag.

WOS:000556610500009 PubMed: 32518775 BACKGROUND Almost 90% of cerebral thromboembolism cases are caused by atherosclerosis. Craniocervical atherosclerosis is often observed at the carotid bifurcation and is responsible for 20%-30% of all stroke cases. The course of atherosclerotic carotid artery stenosis varies depending on the grade of stenosis and characteristics of the plaque. Carotid artery stenting (CAS) can be used as a less invasive method in patients with symptomatic and asymptomatic high-grade carotid artery stenosis. Diffusion-weighted imaging (DWI) is an effective method for detection of silent or symptomatic acute ischemic lesions that may arise due to CAS or carotid endarterectomy. The number and volume of new ischemic lesions are determined using DWI. AIM To evaluate the number and volume of ischemic lesions and their cerebral parenchymal and vascular distribution after CAS using DWI. METHODS Forty-seven male (73.4%) and seventeen female (26.6%) patients (total,n= 64) aged 42-84 years (mean 67.96 +/- 8.03 years) diagnosed with carotid stenosis between October 2006 and July 2012 were included in this retrospective study. Twelve of the cases (18.8%) were asymptomatic, while fifty-two (81.2%) were symptomatic. The area where the stenosis was highest was measured, and the stenosis rate was determined using the North American Symptomatic Carotid Endarterectomy Trial method. DWI of the cases was evaluated by two radiologists experienced in neuroradiology (B.A. with more than 15 years of experience, E.G. with more than 10 years of experience). Routine DWI examinations were carried out by a 1.5 T MR device 1 h before and after the operation. Since the ischemic lesions that developed in the first hour and in the follow-up period of 5-24 h were assumed to be due to CAS, all lesions within the first 24 h were considered as new ischemias. RESULTS In the present study, 39 new ischemic lesions were detected in 20 cases. The average number of new lesions after all CAS operations was 0.62. They were mostly located in the occipital lobes, followed by the frontal and parietal lobes. These new ischemic lesions were most common in the middle cerebral artery territory, followed by the posterior cerebral artery territory and middle cerebral artery-posterior cerebral artery watershed areas. New lesions were found in 31.2% (20/64) of patients, including 17 (26.5%) in ipsilateral and three (4.6%) in contralateral hemispheres. New bilateral lesions were detected in one case (1.5%). The average volume of the new ischemic lesions detected by the two observers was 1.10 cm(3). The numbers of newly appearing ischemic lesions in DWI after CAS were significantly higher in cases where stenting was applied on the left side of the carotid artery and in cases where longer plaques (> 1 cm) were responsible for the narrowing in symptomatic patients. The stenosis rate was low in the group with ulcerated plaques. CONCLUSION New ischemic lesions due to CAS appear mostly in the main arterial territory but they may also occur in watershed areas.

Background Diffusion-weighted imaging (DWI) is an imaging modality using multi-section single-shot spin echo planar imaging (EPI) sequence which is extremely sensitive for detection of water motion within intra, extra, and transcellular regions. This character is important to differentiate between brain tumors either low (benign) or highly (malignant) cellular tumors. Objective To evaluate the role of DWI and apparent diffusion coefficient (ADC) in evaluation and differentiation between different brain posterior fossa tumors in children and adults. Patients and methods The study included 34 patients with different brain posterior fossa tumors for evaluation by conventional MRI (using 1.5 T MRI PHILIPS Achieva 2.1 Best Netherland) and DWI. Results Our study showed that mean ADC values were significantly different between the four groups of posterior fossa tumors in children: juvenile pilocytic astrocytoma (JPA), medulloblastoma, ependymoma, and brain stem glioma while mean ADC values were not significantly different between posterior fossa tumors in the adult group. Regions of interest were manually positioned, and all values were automatically calculated and expressed in 10−3 mm2/s. Conclusion DWI is an ideal additional imaging technique, which is a rapid, easy, non-invasive imaging modality, with no contrast injection needed. It has been widely applied in the differentiation between posterior fossa brain tumors and in the diagnosis of various intracranial diseases.

Highlights • DKI could detect early radiation-induced microstructural abnormalities after CCRT. • The ADC, Dmean, and FA of temporal lobe showed a unique time-dependent trajectory. • Kmean might be more sensitive to detection of effects in the late delayed phases. • White and grey matter all underwent microstructural changes after radiotherapy., Purpose To investigate temporal lobe microstructural abnormalities and neurocognitive function impairment after concurrent chemoradiotherapy (CCRT) in patients with nasopharyngeal carcinoma (NPC). Methods NPC patients who underwent CCRT were enrolled. High-resolution diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) and diffusion-kurtosis imaging (DKI) MRI, were performed 5 times per patient (once pre-CCRT, 1 week post-CCRT, 3 months post-CCRT, 6 months post-CCRT, and 12 months post-CCRT). Neurocognitive function was evaluated by Montreal Neurocognitive Assessment (MoCA) twice per patient, once pre-CCRT, and once 12-months after CCRT. Results Of 111 patients, 56 completed the entire protocol. The MRI derived apparent diffusion coefficient (ADC), mean of diffusion coefficient (Dmean) and fractional anisotropy (FA) values were significantly decreased (p

Diffusion‐weighted imaging (DWI) MRI is very sensitive for detecting small embolic brain infarctions. Stroke as the first manifestation of cancer is extremely rare. We performed a retrospective study to identify the clinical and DWI features of patients with acute ischemic stroke as the first manifestation of occult cancer. A total of five patients in our hospital from January 2017 to May 2019 were analyzed. We also reviewed the literature and seven case series (16 patients) were included. Most of these patients were aged in their sixties and lung cancer was the most common type of occult cancer. Patients showed various presentations of ischemic stroke. All of the patients showed small multiple lesions on DWI that involved mostly the anterior or both anterior and posterior territories. The lesions were mostly in both the supratentorium and infratentorium, with the mechanisms of embolic and watershed infarcts. These features were useful for identifying the causes of embolic stroke. Therefore, patients with small bilateral embolic stroke, especially those involved in multiple vascular territories, should be examined for concealed malignancy.

Background: Executive dysfunctions, including difficulties in attention, working memory, planning, and inhibition affect 15%–28% of multiple sclerosis (MS) patients. Objectives: To investigate structural and functional magnetic resonance imaging (MRI) abnormalities underlying executive function (EF) in MS patients. Methods: A total 116 MS patients and 65 controls underwent resting-state (RS) and diffusion-weighted sequences and neuropsychological examination, including Wisconsin Card Sorting Test (WCST) to test EF. Brain RS cognitive networks and fractional anisotropy (FA) from a priori selected white matter tracts were derived. Associations of WCST scores with RS functional connectivity (FC) and FA abnormalities were investigated. Results: In MS patients, predictors of working memory/updating were: lower corpus callosum (CC) FA, lower left working-memory network (WMN), right WMN RS FC for worse performance; lower executive control network (ECN), higher default-mode network (DMN), and salience network (SN) RS FC for better performance ( R2 = 0.35). Predictors of attention were lower CC genu FA, lower left WMN, and DMN RS FC for worse performance; higher left WMN and ECN RS FC for better performance ( R2 = 0.24). Predictors of worse shifting/inhibition were lower CC genu and superior cerebellar peduncle (SCP) FA, lower left WMN RS FC for worse performance; and higher ECN RS FC for better performance ( R2 = 0.24). Conclusions: CC and SCP microstructural damage and RS FC abnormalities in cognitive networks underlie EF frailty in MS.

Background The 3D U-Net model has been proved to perform well in the automatic organ segmentation. The aim of this study is to evaluate the feasibility of the 3D U-Net algorithm for the automated detection and segmentation of lymph nodes (LNs) on pelvic diffusion-weighted imaging (DWI) images. Methods A total of 393 DWI images of patients suspected of having prostate cancer (PCa) between January 2019 and December 2020 were collected for model development. Seventy-seven DWI images from another group of PCa patients imaged between January 2021 and April 2021 were collected for temporal validation. Segmentation performance was assessed using the Dice score, positive predictive value (PPV), true positive rate (TPR), and volumetric similarity (VS), Hausdorff distance (HD), the Average distance (AVD), and the Mahalanobis distance (MHD) with manual annotation of pelvic LNs as the reference. The accuracy with which the suspicious metastatic LNs (short diameter > 0.8 cm) were detected was evaluated using the area under the curve (AUC) at the patient level, and the precision, recall, and F1-score were determined at the lesion level. The consistency of LN staging on an hold-out test dataset between the model and radiologist was assessed using Cohen’s kappa coefficient. Results In the testing set used for model development, the Dice score, TPR, PPV, VS, HD, AVD and MHD values for the segmentation of suspicious LNs were 0.85, 0.82, 0.80, 0.86, 2.02 (mm), 2.01 (mm), and 1.54 (mm) respectively. The precision, recall, and F1-score for the detection of suspicious LNs were 0.97, 0.98 and 0.97, respectively. In the temporal validation dataset, the AUC of the model for identifying PCa patients with suspicious LNs was 0.963 (95% CI: 0.892–0.993). High consistency of LN staging (Kappa = 0.922) was achieved between the model and expert radiologist. Conclusion The 3D U-Net algorithm can accurately detect and segment pelvic LNs based on DWI images.

Introduction: We compared the magnetic resonance imaging total tumor volume (TTV) and median apparent diffusion coefficient (ADC) of malignant pleural mesothelioma (MPM) before and at 4 weeks after chemotherapy, to evaluate whether these are potential early markers of treatment response. Methods: Diffusion-weighted magnetic resonance imaging was performed in 23 patients with MPM before and after 4 weeks of chemotherapy. The TTV was measured by semiautomatic segmentation (GrowCut) and transferred onto ADC maps to record the median ADC. Test-retest repeatability of TTV and ADC was evaluated in eight patients. TTV and median ADC changes were compared between responders and nonresponders, defined using modified Response Evaluation Criteria In Solid Tumors on computed tomography (CT) at 12 weeks after treatment. TTV and median ADC were also correlated with CT size measurement and disease survival. Results: The test-retest 95% limits of agreement for TTV were −13.9% to 16.2% and for median ADC −1.2% to 3.3%. A significant increase in median ADC in responders was observed at 4 weeks after treatment (p = 0.02). Correlation was found between CT tumor size change at 12 weeks and median ADC changes at 4 weeks post-treatment (r = −0.560, p = 0.006). An increase in median ADC greater than 5.1% at 4 weeks has 100% sensitivity and 90% specificity for responders (area under the curve = 0.933, p < 0.001). There was also moderate correlation between median tumor ADC at baseline and overall survival (r = 0.45, p = 0.03). Conclusions: Diffusion-weighted magnetic resonance imaging measurements of TTV and median ADC in MPM have good measurement repeatability. Increase in ADC at 4 weeks post-treatment has the potential to be an early response biomarker.

The shortly upcoming 5th edition of the World Health Organization Classification of Tumors of the Central Nervous System is bringing extensive changes in the terminology of diffuse high-grade gliomas (DHGGs). Previously “glioblastoma,” as a descriptive entity, could have been applied to classify some tumors from the family of pediatric or adult DHGGs. However, now the term “glioblastoma” has been divested and is no longer applied to tumors in the family of pediatric types of DHGGs. As an entity, glioblastoma remains, however, in the family of adult types of diffuse gliomas under the insignia of “glioblastoma, IDH-wildtype.” Of note, glioblastomas still can be detected in children when glioblastoma, IDH-wildtype is found in this population, despite being much more common in adults. Despite the separation from the family of pediatric types of DHGGs, what was previously labeled as “pediatric glioblastomas” still remains with novel labels and as new entities. As a result of advances in molecular biology, most of the previously called “pediatric glioblastomas” are now classified in one of the four family members of pediatric types of DHGGs. In this review, the term glioblastoma is still apocryphally employed mainly due to its historical relevance and the paucity of recent literature dealing with the recently described new entities. Therefore, “glioblastoma” is used here as an umbrella term in the attempt to encompass multiple entities such as astrocytoma, IDH-mutant (grade 4); glioblastoma, IDH-wildtype; diffuse hemispheric glioma, H3 G34-mutant; diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype; and high grade infant-type hemispheric glioma. Glioblastomas are highly aggressive neoplasms. They may arise anywhere in the developing central nervous system, including the spinal cord. Signs and symptoms are non-specific, typically of short duration, and usually derived from increased intracranial pressure or seizure. Localized symptoms may also occur. The standard of care of “pediatric glioblastomas” is not well-established, typically composed of surgery with maximal safe tumor resection. Subsequent chemoradiation is recommended if the patient is older than 3 years. If younger than 3 years, surgery is followed by chemotherapy. In general, “pediatric glioblastomas” also have a poor prognosis despite surgery and adjuvant therapy. Magnetic resonance imaging (MRI) is the imaging modality of choice for the evaluation of glioblastomas. In addition to the typical conventional MRI features, i.e., highly heterogeneous invasive masses with indistinct borders, mass effect on surrounding structures, and a variable degree of enhancement, the lesions may show restricted diffusion in the solid components, hemorrhage, and increased perfusion, reflecting increased vascularity and angiogenesis. In addition, magnetic resonance spectroscopy has proven helpful in pre- and postsurgical evaluation. Lastly, we will refer to new MRI techniques, which have already been applied in evaluating adult glioblastomas, with promising results, yet not widely utilized in children.

In this study, the objective was to characterize the MR signatures of the various benign prostate tissues and to differentiate them from cancer. Data was from seventy prostate cancer patients who underwent multiparametric MRI (mpMRI) and subsequent prostatectomy. The scans included T2-weighted imaging (T2W), diffusion weighted imaging, dynamic contrast-enhanced MRI (DCE MRI), and MR spectroscopic imaging. Histopathology tissue information was translated to MRI images. The mpMRI parameters were characterized separately per zone and by tissue type. The tissues were ordered according to trends in tissue parameter means. The peripheral zone tissue order was cystic atrophy, high grade prostatic intraepithelial neoplasia (HGPIN), normal, atrophy, inflammation, and cancer. Decreasing values for tissue order were exhibited by ADC (1.8 10(−3) mm(2)/sec to 1.2 10(−3)mm(2)/sec) and T2W intensity (3447 to 2576). Increasing values occurred for DCE MRI peak (143% to 157%), DCE MRI slope (101%/min to 169%/min), fractional anisotropy (FA) (0.16 to 0.19), choline (7.2 to 12.2), and choline / (creatine + citrate) (0.3 to 0.9). The transition zone tissue order was cystic atrophy, mixed benign prostatic hyperplasia (BPH), normal, atrophy, inflammation, stroma, anterior fibromuscular stroma, and cancer. Decreasing values occurred for ADC (1.6 10(−3) mm(2)/sec to 1.1 10(−3)mm(2)/sec) and T2W intensity (2863 to 2001). Increasing values occurred for DCE MRI peak (143% to 150%), DCE MRI slope (101%/min to 137%/min), FA (0.18 to 0.25), choline (7.9 to 11.7), and choline / (creatine + citrate) (0.2 to 0.6). Logistic regression was used to create parameter model fits to differentiate cancer from benign prostate tissues. The fits achieved AUCs ≥ 0.91. This study quantified the mpMRI characteristics of benign prostate tissues and demonstrated the capability of mpMRI to discriminate among benign as well as cancer tissues, potentially aiding future discrimination of cancer from benign confounders.

Background: Strong correlation has been reported between tissue water diffusivity and tissue elasticity in the liver. The purpose of this study is to explore the capability of diffusion–based virtual MR elastography (VMRE) in the characterization of liver tumors by extending beyond liver fibrosis assessments. Methods: Fifty-four patients (56 liver tumors: hepatocellular carcinoma (HCC), 31, metastases, 25) who underwent MRE, diffusion-weighted imaging (DWI) (b: 0, 800 s/mm2), and VMRE (b: 200, 1500 s/mm2) were enrolled. The MRE shear modulus (µMRE), apparent diffusion coefficient (ADC), and shifted ADC (sADC) were obtained. Virtual stiffness (µdiff) was estimated from the relationship between µMRE and sADC. A linear discriminant analysis combining VMRE and MRE to classify HCC and metastases was performed in a training cohort (thirty-two patients) to estimate a classifier (C), and evaluate its accuracy in a testing cohort (twenty-two patients). Pearson’s correlations between µMRE, sADC, and ADC were evaluated. In addition to the discriminant analysis, a receiver operating characteristic (ROC) curve was used to assess the discrimination capability between HCC and metastases. Results: The correlations between µMRE and sADC were significant for liver, HCC, and metastases (r = 0.91, 0.68, 0.71, all p &lt, 0.05). Those between µMRE and ADC were weaker and significant only for metastases (r = 0.17, 0.20, 0.55). µdiff values were not significantly different between HCC and metastases (p = 0.56). Areas under the curves (AUC) to differentiate HCC from metastases were as follows: VMRE, 0.46, MRE alone, 0.89, MRE + VMRE, 0.96. The classifier C also provided better performance than MRE alone, in terms of sensitivity (100 vs. 93.5%, respectively) and specificity (92 vs. 76%, respectively, p = 0.046). Conclusions: The correlation between sADC and µMRE was strong both in the liver and in tumors. However, VMRE alone could not classify HCC and metastases. The combination of MRE and VMRE, however, allowed discriminant performance between HCC and metastases.

Background: Visual snow is considered a disorder of central visual processing resulting in a perturbed perception of constant binocular flickering or pixilation of the whole visual field. The underlying neurophysiological and structural alterations remain elusive.Methods: In this study, we included patients (final n = 14, five dropouts; five females, mean age: 32 years) with visual snow syndrome (VSS) and age- and sex-matched controls (final n = 20, 6 dropouts, 13 females, mean age: 28.2 years). We applied diffusion tensor imaging to examine possible white matter (WM) alterations in patients with VSS.Results: The patient group demonstrated higher (p-corrected < 0.05, adjusted for age and sex) fractional anisotropy (FA) and lower mean diffusivity (MD) and radial diffusivity (RD) compared to controls. These changes were seen in the prefrontal WM (including the inferior fronto-occipital fascicle), temporal and occipital WM, superior and middle longitudinal fascicle, and sagittal stratum. When additionally corrected for migraine or tinnitus—dominant comorbidities in VSS—similar group differences were seen for FA and RD, but less pronounced.Conclusions: Our results indicate that patients with VSS present WM alterations in parts of the visual cortex and outside the visual cortex. As parts of the inferior fronto-occipital fascicle and sagittal stratum are associated with visual processing and visual conceptualisation, our results suggest that the WM alterations in these regions may indicate atypical visual processing in patients with VSS. Yet, the frequent presence of migraine and other comorbidities such as tinnitus in VSS makes it difficult to attribute WM disruptions solely to VSS.

Background: Neoadjuvant chemotherapy (NAC) is known to be a suitable treatment and first-line defense for locally advanced breast cancer. However, the NAC response may include unexpected outcomes, and it is not easy to predict the NAC response precisely. Especially, early detection of those patients who do not benefit from NAC is needed to reduce unnecessary therapy and side effects. Objective: The purpose of this study was to determine whether the pretreatment apparent diffusion coefficient (ADC) value is effective for predicting the response of breast cancer to NAC. Method: Forty-nine breast cancer cases with pre- and post-NAC breast MRI were enrolled. MRI was performed using a 1.5-T scanner with the basic protocol including diffusion-weighted imaging. ADC difference value (ADC-diff) was calculated in all cases. Results: ADC-diff was high in complete response and partial response cases ( p

This study aimed to establish and validate a radiomics nomogram using the radiomics score (rad-score) based on multiregional diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) features combined with clinical factors for evaluating HER-2 2+ status of breast cancer. A total of 223 patients were retrospectively included. Radiomic features were extracted from multiregional DWI and ADC images. Based on the intratumoral, peritumoral, and combined regions, three rad-scores were calculated using the logistic regression model. Independent parameters were selected among clinical factors and combined rad-score (com-rad-score) using multivariate logistic analysis and used to construct a radiomics nomogram. The performance of the nomogram was evaluated using calibration, discrimination, and clinical usefulness. The areas under the receiver operator characteristic curve (AUCs) of intratumoral and peritumoral rad-scores were 0.824/0.763 and 0.794/0.731 in the training and validation cohorts, respectively. Com-rad-score achieved the highest AUC (0.860/0.790) among three rad-scores. ER status and com-rad-score were selected to establish the nomogram, which yielded good discrimination (AUC: 0.883/0.848) and calibration. Decision curve analysis demonstrated the clinical value of the nomogram in the validation cohort. In conclusion, radiomics nomogram, including clinical factors and com-rad-score, showed favorable performance for evaluating HER-2 2+ status in breast cancer.

Objective: This paper summarizes the MRI imaging findings of primary central nervous system lymphoma (PCNSL) in the posterior cranial fossa to improve the accuracy of PCNSL diagnosis in the posterior cranial fossa. Methods: This study retrospectively analyzed the MRI imaging manifestations of 15 PCNSL posterior cranial fossa cases confirmed by puncture or surgical pathology from June 2017 to May 2018, including their occurrence sites, the number of lesions, MRI plain and enhanced manifestations, and diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy. Imaging (MRS) performance. Results: A total of 15 cases were enrolled, including 10 cases of single lesion and five cases of multiple lesions. The total number of lesions was 25, which were in the cerebellar hemisphere and cerebellar vermis, midbrain, fourth ventricle, and pontine cerebellum. The lesions were round, irregular, nodular, patchy, with low or medium signals on T1WI, equal or slightly higher signals on T2WI, and enhanced with 25 meningiomas-like gray matter signals. All of them were significantly strengthened. “Acupoint sign” and “umbilical depression sign” were seen in eight lesions. There were 17 massive and nodular enhancements, four striped enhancements, three patchy enhancements, and one circular enhancement. five cases of DWI showed homogeneous high signal, two cases showed uneven high signal, and 3 cases showed medium signal. The ADC value of tumor parenchyma in 10 patients was (0.62±0.095)×10-3mm2/s. MRS examination showed obvious Lip peak in two cases. Conclusion: PCNSL in posterior cranial fossa has certain characteristics. DWI, ADC value and MRS are helpful to improve the correct diagnosis rate of PCNSL. doi: https://doi.org/10.12669/pjms.37.6-WIT.4843 How to cite this:Lu G, Li Y, Liang X, Zhao Z. Diagnosis and analysis of primary central nervous system lymphoma based on MRI segmentation algorithm. Pak J Med Sci. 2021;37(6):1585-1589. doi: https://doi.org/10.12669/pjms.37.6-WIT.4843 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background Radiological differentiation between benign and malignant gallbladder disease is important but remains challenging. Furthermore, the clinical value of diffusion-weighted imaging (DWI) remains unclear. Purpose To determine the value of DWI in discriminating benign from malignant gallbladder disease by conducting a systematic review and meta-analysis. Material and Methods The literature was systematically searched. Studies analyzing diagnostic value of DWI in gallbladder disease with histopathology or follow-up as reference standard were included. Study selection and data extraction were done by two reviewers independently. Methodological quality was assessed using the QUADAS-2 tool. Sensitivity and specificity were calculated and displayed in a forest plot. A sensitivity analysis was performed in case of outliers. Pooled sensitivity and specificity of DWI were plotted on a hierarchical summary receiver operating characteristic curve. If available, the added value of DWI to conventional magnetic resonance imaging (MRI) sequences was analyzed. Results Out of 2456 articles, eight studies fulfilled the inclusion criteria; 592 patients with 221 malignant lesions were included. Pooled sensitivity and specificity rates were 0.87 and 0.84, respectively. In two studies, diagnostic accuracy rates improved after adding DWI to conventional MRI (64% and 75% for conventional MRI vs. 89% and 94% after combining conventional MRI with DWI). In another study, the area under the curve increased from 0.92 to 0.95. Conclusion DWI appears to be an accurate imaging technique in discriminating benign from malignant gallbladder disease. To achieve optimal patient care, it should be part of multiparametric MRI and should be combined with other imaging modalities.

The purpose of this article was to show basic principles, acquisition, advantages, disadvantages, and clinical applications of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI). IVIM MRI as a method was introduced in the late 1980s, but recently it started attracting more interest thanks to its applications in many fields, particularly in oncology and neuroradiology. This imaging technique has been developed with the objective of obtaining not only a functional analysis of different organs but also different types of lesions. Among many accessible tools in diagnostic imaging, IVIM MRI aroused the interest of many researchers in terms of studying its applicability in the evaluation of abdominal organs and diseases. The major conclusion of this article is that IVIM MRI seems to be a very auspicious method to investigate the human body, and that nowadays the most promising clinical application for IVIM perfusion MRI is oncology. However, due to lack of standardisation of image acquisition and analysis, further studies are needed to validate this method in clinical practice.

Background and aim To analyze the incidence of peripheral emboli after successful mechanical thrombectomy (MT) of intracranial large vessel occlusions (LVO). Methods We performed a prospective analysis of patients with intracranial LVO who underwent successful MT and received a 1.5 T MRI including diffusion-weighted imaging (DWI) in standard- and high-resolution as well as susceptibility-weighted imaging (SWI) on the day following the intervention. Reperfusion grade was assessed on post-thrombectomy digital subtraction angiography (DSA) using the expanded thrombolysis in cerebral infarction (eTICI) scale. Punctuate DWI lesions distal to the DWI core lesion were classified as peripheral emboli. DWI lesions outside the primary affected vascular territory were classified as emboli into new territories. Additionally, SWI and post-thrombectomy DSA were analyzed and correlated to findings on DWI. Results Twenty-eight patients undergoing successful MT met the inclusion criteria. In 26/28 patients (93%), a total of 324 embolic lesions were detected in DWI representing 2.1% of the cumulated ischemic core volume. 151 peripheral emboli were detected in standard-resolution DWI, 173 additional emboli were uncovered in high-resolution DWI. Eight out of nine patients with an eTICI 3 reperfusion had embolic lesions (29 DWI lesions). 9.6% (31/324) of peripheral emboli were observed in vascular territories not affected by the LVO. SWI lesions were observed in close proximity to 10.2% (33/324) of DWI lesions. Conclusions Peripheral emboli are frequent after MT even after complete reperfusion. These emboli occur rather in the vascular territory of the occluded vessel than in other territories. A large proportion of peripheral emboli is only detected by high-resolution DWI.

Introduction: This study aimed to compare the apparent diffusion coefficient (ADC) values of different brain areas between two groups of intrauterine growth restricted (IUGR) foetuses and control cases. Material and methods: A total of 38 foetuses with IUGR and 18 normal control foetuses with similar gestational age were compared using a 3T magnetic resonance scanner. IUGR cases included 23 foetuses with clinical severity signs (group A) and 15 foetuses without clinical severity signs (group B). ADC values were measured in different brain regions and compared among groups. Foetuses with structural brain abnormalities were excluded from the study. Results: All foetuses had normal foetal structural brain anatomy. Head circumference (HC) < 5% was more common in IUGR group A compared to IUGR group B (56.5% vs. 13.3%, p < 0.0001). In comparison to the normal group, the ADC values in IUGR foetuses were significantly lower in cerebellar hemispheres (CH) (1.239 vs. 1.280.5 × 10-3 mm2/s, p = 0.045), thalami (1.205 vs. 1.285 × 10–3 mm2/s, p = 0.031) and caudate nucleus (CN) (1.319 vs. 1.394 × 10-3 mm2/s, p = 0.04). However, there were no significant differences in ADC values between IUGR subtypes. Among all brain regions, pons had the lowest ADC values. Conclusions: ADC values of thalami, CN, and CH were significantly lower in IUGR than control foetuses, while there was no significant difference among IUGR groups. Further studies are needed to evaluate the prognostic value of ADC changes in IUGR foetuses.

Diffusion tensor imaging is often used to assess white matter (WM) changes following traumatic brain injury (TBI), but is limited in voxels that contain multiple fibre tracts. Fixel‐based analysis (FBA) addresses this limitation by using a novel method of analysing high angular resolution diffusion‐weighted imaging (HARDI) data. FBA examines three aspects of each fibre tract within a voxel: tissue micro‐structure (fibre density [FD]), tissue macro‐structure (fibre‐bundle cross section [FC]) and a combined measure of both (FD and fibre‐bundle cross section [FDC]). This study used FBA to identify the location and extent of micro‐ and macro‐structural changes in WM following TBI. A large TBI sample (N mild = 133, N moderate–severe = 29) and control group (healthy and orthopaedic; N = 107) underwent magnetic resonance imaging with HARDI and completed reaction time tasks approximately 7 months after their injury (range: 98–338 days). The TBI group showed micro‐structural differences (lower FD) in the corpus callosum and forceps minor, compared to controls. Subgroup analyses revealed that the mild TBI group did not differ from controls on any fixel metric, but the moderate to severe TBI group had significantly lower FD, FC and FDC in multiple WM tracts, including the corpus callosum, cerebral peduncle, internal and external capsule. The moderate to severe TBI group also had significantly slower reaction times than controls, but the mild TBI group did not. Reaction time was not related to fixel findings. Thus, the WM damage caused by moderate to severe TBI manifested as fewer axons and a reduction in the cross‐sectional area of key WM tracts.

Purpose The reproducibility of neurite orientation dispersion and density imaging (NODDI) metrics in the human brain has not been explored across different magnetic resonance (MR) scanners from different vendors. This study aimed to evaluate the scan–rescan and inter-vendor reproducibility of NODDI metrics in white and gray matter of healthy subjects using two 3-T MR scanners from two vendors. Methods Ten healthy subjects (7 males; mean age 30 ± 7 years, range 23–37 years) were included in the study. Whole-brain diffusion-weighted imaging was performed with b-values of 1000 and 2000 s/mm2 using two 3-T MR scanners from two different vendors. Automatic extraction of the region of interest was performed to obtain NODDI metrics for whole and localized areas of white and gray matter. The coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated to assess the scan–rescan and inter-vendor reproducibilities of NODDI metrics. Results The scan–rescan and inter-vendor reproducibility of NODDI metrics (intracellular volume fraction and orientation dispersion index) were comparable with those of diffusion tensor imaging (DTI) metrics. However, the inter-vendor reproducibilities of NODDI (CoV = 2.3–14%) were lower than the scan–rescan reproducibility (CoV: scanner A = 0.8–3.8%; scanner B = 0.8–2.6%). Compared with the finding of DTI metrics, the reproducibility of NODDI metrics was lower in white matter and higher in gray matter. Conclusion The lower inter-vendor reproducibility of NODDI in some brain regions indicates that data acquired from different MRI scanners should be carefully interpreted.

Introduction Glioblastoma (GBM) is the most common malignant primary brain tumor, and methods to improve the early detection of disease progression and evaluate treatment response are highly desirable. We therefore explored changes in whole-brain apparent diffusion coefficient (ADC) values with respect to survival (progression-free [PFS], overall [OS]) in a cohort of GBM patients followed at regular intervals until disease progression. Methods A total of 43 subjects met inclusion criteria and were analyzed retrospectively. Histogram data were extracted from standardized whole-brain ADC maps including skewness, kurtosis, entropy, median, mode, 15th percentile (p15) and 85th percentile (p85) values, and linear regression slopes (metrics versus time) were fitted. Regression slope directionality (positive/negative) was subjected to univariate Cox regression. The final model was determined by aLASSO on metrics above threshold. Results Skewness, kurtosis, median, p15 and p85 were all below threshold for both PFS and OS and were analyzed further. Median regression slope directionality best modeled PFS (p = 0.001; HR 3.3; 95% CI 1.6–6.7), while p85 was selected for OS (p = 0.002; HR 0.29; 95% CI 0.13–0.64). Conclusions Our data show tantalizing potential in the use of whole-brain ADC measurements in the follow up of GBM patients, specifically serial median ADC values which correlated with PFS, and serial p85 values which correlated with OS. Whole-brain ADC measurements are fast and easy to perform, and free of ROI-placement bias.

Background Stroke is a leading cause of serious disability and death and its accurate and timely diagnosis is critical for better stroke outcomes. However, recent studies indicate that stroke is among the most common dangerous missed diagnoses. Diffusion-weighted imaging (DWI), which was first introduced in the early 1990s among clinical concerns, has become an invaluable tool in the evaluation processes of patients with suspected ischemic stroke. Objective Herein, it is aimed to investigate the reliability of the interpretation of DWI in the diagnosis of stroke by emergency physicians. Methods DWIs of the patients, evaluated in the Emergency Service of Yozgat City Hospital from April 1, 2017 to September 1, 2017, were retrospectively evaluated by four emergency physicians (specialists) separately in a blind and random fashion. The reliability of the evaluations was calculated using Kappa analyses on SPSS Statistics 20. Results DWI of 154 patients was enrolled in this study. Kappa values were determined to be as 0.911 (almost perfect), 0.909 (almost perfect), 0.897 (almost perfect), 0.779 (substantial), respectively. Discussion The results of this study may suggest that the reliability of DWI interpretation by emergency physicians was pretty high, even it can still be improved. Combining the literature data remarking a substantial number of misdiagnosed stroke patients in the emergency department (ED) and study results, it can be hypothesized that the major problem may be related with rather clinical evaluation processes as well as insufficient neurology consultation. Future reports are warranted to understand the basic problems of stroke evaluation processes in the ED. The results of these studies may aid to develop better solutions while constituting effective stroke programs and initiatives.