Search

Background: To assess the value of tripartite magnetic resonance imaging model based on T2-weighted imaging (T2-WI), diffusion-weighted imaging (DWI) as well as dynamic contrast-enhanced imaging (DCE) for the diagnosis of prostatitis, prostatic hyperplasia and prostate cancer. Materials and Methods: A total of 100 patients with prostatic diseases were selected from our hospital from January 2020 to December 2022. All patients underwent T2-WI, DWI and DCE examination. Results: Among the 100 suspected patients, 40 were diagnosed with prostate cancer, 30 were prostatitis, and 30 were prostate hyperplasia. Apparent diffusion coefficient (ADC) value was reduced in prostate cancer patients compared to the prostatic hyperplasia as well as prostatitis groups (P<0.05). No difference was discovered in ADC value between the prostatic prostatic hyperplasia and prostatitis groups (P>0.05). Moreover, the diagnosis efficacy of the tripartite magnetic resonance imaging model was higher compared to those of prostate imaging reporting and data system version 2 (PI-RADS V2). Conclusion: The tripartite magnetic resonance imaging model based on T2-WI, DWI, as well as DCE has high diagnostic accuracy in prostatic diseases, with high sensitivity and low misdiagnosis rate, which might be valuable in clinical application. [ABSTRACT FROM AUTHOR]

Background: To explore the application of intravoxel incoherent motion (IVIM) parameters based on mono- and bi-exponential models for diagnosing breast cancer (BC). Materials and Methods: 43 patients underwent breast magnetic resonance (MR) scanned before operation and the images were transferred to AW Volume Share 5 post-processing workstation. The mono-exponential and bi-exponential model was used to measure the slow diffusion coefficient (DC) (D), fast DC (D*) and fraction of perfusion (f). And the association between different parameter values and BC grading was analyzed via Spearman's rank correlation coefficient. Results: The D mono value of 13 patients with benign breast diseases was higher than that of 30 patients with BC (4.04 ± 0.23 vs 2.59 ± 0.64,p<0.05) while there was no statistical significance on the value of D* mono, f mono, D bi, D* bi and f bi. Additionally, the parameter differences of D mono, D* mono, D bi and D* bi had statistical significance between the different BC grades. And the grades of BC had a negative correlation with D mono and D bi while were positively related to D* mono and D* bi. It was most closely related to D* bi than D bi. D mono value in ER-positive were higher than that in ER-negative group (3.09±0.37 vs 1.03±0.09, p=.0095). Conclusion: IVIM could be used to diagnose BC, predict histological grading and ER expression and provide valuable imaging for the clinical treatment and prognosis of BC patients. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) is increasingly being used to diagnose bone marrow lesions in patients with multiple myeloma (MM). Since 2014, the results of MRI have been included in the updated criteria of the International Myeloma Working Group. The presence of >1 bone marrow lesion larger than or equal to 5 mm on MRI is considered sufficient for the diagnosis of symptomatic MM, requiring initiation of treatment. MRI assessment of bone marrow is also possible with functional sequences such as diffusion-weighted imaging (DWI), which provide additional information about the bone marrow. This article provides an overview of the possibilities of MRI with anatomical sequences and with DWI for diagnosing, monitoring and evaluating the response to treatment in patients with MM. In patients with monoclonal gammopathy of undetermined significance and smoldering myeloma, in some cases, pathological changes in the bone marrow can be detected by MRI. The presence of >1 bone marrow lesion on MRI is a cut-off value as a prognostic factor for the progression of monoclonal gammopathy of undetermined significance or smoldering myeloma to symptomatic MM. In symptomatic MM, there are four patterns of bone marrow infiltration on MRI – focal, diffuse, “salt-and-pepper” infiltration, and combined diffuse and focal pattern, which have prognostic significance. Patients with diffuse pattern of infiltration on MRI had a 3-year overall survival of 35 % versus 92 % in patients with normal MRI bone marrow. During treatment of MM patients, residual bone marrow lesions are often identified on MRI. MRI residual bone marrow lesions increase the risk of MM relapse. In the group of patients who had residual bone marrow lesions on MRI on the 100th day after autologous hematopoietic stem cell transplant, 2-year progression-free survival was 50 % versus 89 % in patients without bone marrow lesions at the same time. The addition of DWI to the scan protocol helps to differentiate persistent focal bone marrow lesions that can lead to MM relapse after the treatment phase. Apparent diffusion coefficient is a quantitative indicator of DWI. MRI can serve as a valuable tool for assessing the treatment response in patients with MM.

Purpose: Mucinous adenocarcinoma (MA) is associated with worse clinicopathological characteristics and a poorer prognosis than non-MA. Moreover, MA is related to worse tumor regression grade and tumor downstaging than non-MA. This study investigated whether lesions in MA and non-MA can be quantitatively assessed by T2 mapping technique and compared with the diffusion-weighted imaging (DWI). Methods: High-resolution MRI, DWI, and T2 mapping were performed on 81 patients diagnosed with rectal cancer via biopsy. Afterward, T2 and apparent diffusion coefficient (ADC) values were manually measured by a senior and a junior radiologist independently. By examining surgical specimens, the patients with MA and non-MA were identified. Inter-observer reproducibility was tested, and T2 and ADC values were compared using Mann--Whitney U test. Finally, receiver operating characteristic (ROC) curves were drawn to determine the cut-off value. Results: Of the 81 patients, 11 patients with MA were confirmed by pathology. The inter-observer reproducibility of T2 and ADC values showed an excellent intraclass correlation coefficient (ICC) of 0.993 and 0.913, respectively. MA had higher T2 (87.9 ± 5.11 ms) (P = 0.000) and ADC (2.03 x 10-3 mm²/s) (P = 0.000) values than non-MA (66.6 ± 6.86 ms and 1.17 x 10-3 mm²/s/s, respectively). The area under the ROC curves (AUC) of the T2 and ADC values were 0.999 (95% confidence interval [CI]: 0.953-1) and 0.979 (95% CI: 0.920--0.998), respectively.When the cutoff value in T2 mapping was 80 ms, the Youden index was the largest, sensitivity was 100%, and specificity was 97%. Conclusion: As a stable quantitative sequence, T2 mapping of MRI is useful in differentiating MA from non-MA. Compared to ADC values, T2 values are also diagnostically effective and non-inferior to ADC values. [ABSTRACT FROM AUTHOR]

Purpose To compare diffusion-weighted imaging (DWI) with thermal dosimetry as a noncontrast method to predict ablation margins in individuals with prostate cancer treated with MRI-guided focused ultrasound (MRgFUS) ablation. Materials and Methods This secondary analysis of a prospective trial (ClinicalTrials.gov no. NCT01657942) included 17 participants (mean age, 64 years ± 6 [SD]; all male) who were treated for prostate cancer using MRgFUS in whom DWI was performed immediately after treatment. Ablation contours from computed thermal dosimetry and DWI as drawn by two blinded radiologists were compared against the reference standard of ablation assessment, posttreatment contrast-enhanced nonperfused volume (NPV) contours. The ability of each method to predict the ablation zone was analyzed quantitively using Dice similarity coefficients (DSCs) and mean Hausdorff distances (mHDs). Results DWI revealed a hyperintense rim at the margin of the ablation zone. While DWI accurately helped predict treatment margins, thermal dose contours underestimated the extent of the ablation zone compared with the T1-weighted NPV imaging reference standard. Quantitatively, contour assessment between methods showed that DWI-drawn contours matched postcontrast NPV contours (mean DSC = 0.84 ± 0.05 for DWI, mHD = 0.27 mm ± 0.13) better than the thermal dose contours did (mean DSC = 0.64 ± 0.12, mHD = 1.53 mm ± 1.20) ( P < .001). Conclusion This study demonstrates that DWI, which can visualize the ablation zone directly, is a promising noncontrast method that is robust to treatment-related bulk motion compared with thermal dosimetry and correlates better than thermal dosimetry with the reference standard T1-weighted NPV. Keywords: Interventional-Body, Ultrasound-High-Intensity Focused (HIFU), Genital/Reproductive, Prostate, Oncology, Imaging Sequences, MRI-guided Focused Ultrasound, MR Thermometry, Diffusionweighted Imaging, Prostate Cancer ClinicalTrials.gov Identifier no. NCT01657942 Supplemental material is available for this article. © RSNA, 2024.

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. [ABSTRACT FROM AUTHOR]

Background: Pleural effusion could develop in very different pathological conditions. It is important to characterize pleural effusion and to identify its etiology. Different radiological methods, such as ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) are used for the diagnosis of pleural effusion. Objectives: To assess the ability of diffusion weighted imaging and apparent diffusion coefficient (ADC) maps to differentiate transudative effusions (TEs) from exudative effusions (EEs). Patients and Methods: This prospective observational, single center study was performed on 100 consecutive patients who had pleural fluid detected by chest X-ray, US, or CT and were referred for MRI. Afterwards diffusion-weighted MRI (DW-MRI) was obtained using a multislice, single shot, respiratory triggered spin echo, echo planar imaging sequence. Pleural effusions obtained with thoracentesis were classified into TEs or EEs according to the clinical criteria established by clinical, pathologic findings and Light's criteria. Analysis of MRI was interpreted by one radiologist specialist who was blinded to clinical findings and according to the clinical criteria established by Light. Results: The ADCs of EEs were significantly lower than those of the TEs. The difference between the mean ADC values of TEs and EEs was significant (P < 0.01). The optimum cutoff point for ADC values was 3.51 x 10-3mm²/s, with a sensitivity of 90.4% and a specificity of 78%. Conclusion: We conclude that ADC value is a noninvasive, reliable, and reproducible imaging parameter that may help to assess and characterize pleural effusion. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) features of endometrial stromal sarcoma (ESS) including a preliminary investigation of the correlation between the apparent diffusion coefficient (ADC) value and Ki-67 expression. Methods: The clinical and MRI data of 15 patients with ESS confirmed by surgery and pathology were analyzed retrospectively. The conventional MR morphological features, signal intensity on DWI, ADC value (n = 14), and clinicopathological marker Ki-67 (n = 13) were evaluated. Results: Of 15 patients with ESS, 13 tumors were low-grade ESS (LGESS), and the remaining 2 were high-grade ESS (HGESS); 9 tumors were located in the myometrium, 5 were located in the endometrium and/or cervical canal, and 1 was located in extrauterine. Thirteen (87%) of 15 tumors showed a homo- or heterogeneous isointensity on T1-weighted imaging and a heterogeneous hyperintensity on T2-weighted imaging. The hypointense bands were observed in 11 tumors (73%) on T2-weighted imaging. The degenerations (cystic/necrosis/ hemorrhage)were observed in 7 LGESS tumors and 2 HGESS tumors. The DWI hyperintensity was observed in 13 tumors (93%) and isointensity in remaining 1. The mean ADC value of the solid components in 14 ESSs was (1.05 ± 0.20) × 10-3mm2/s. The contrast-enhanced MRI showed an obvious enhancement in 14 tumors (93%) (heterogeneous in 7 LGESSs and 2 HGESSs; homogeneous in 5 LGESSs). The ADC value was inversely correlated with the Ki-67 expression (r =-0.613, P = 0.026). Conclusions: Patients with ESS showed some characteristics on conventional MRI and DWI, and there was an inverse correlation between the ADC value and Ki-67 expression. [ABSTRACT FROM AUTHOR]

This study explored the predictive values of diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) in evaluating the efficacy of transcatheter arterial chemoembolization (TACE) for patients with hepatocellular carcinoma (HCC). A total of 118 HCC patients treated with TACE were selected from April 2013 to November 2015. T1-weighted imaging (T1WI)/T2-weighted imaging (T2WI), DWI, and PWI were performed on all patients before and after TACE. Efficacy was evaluated according to modified Response Evaluation Criteria in Solid Tumors 1.1. Receiver operating characteristic curve was used to evaluate the diagnostic power of quantitative DWI and PWI parameters in evaluating the efficacy of TACE for HCC patients. Among the 118 HCC patients, there were 17 cases (14.4%) with complete response, 50 cases (42.4%) with partial response, 28 cases (23.7%) with stable disease, and 23 cases (19.5%) with progressive disease. There were 67 patients in the effective group (complete response + partial response) and 51 patients in the ineffective group (stable disease + progressive disease). Before TACE, there were significant differences in maximum tumor diameter (MTD), apparent diffusion coefficient (ADC), slow ADC (Dslow), fast ADC (Dfast), transfer constant of vessel at the maximum level (Ktrans), and rate constant of backflux (Kep) between the effective and ineffective groups (all P<0.05). After TACE, the effective group exhibited lower MTD, Dfast, and Kep and higher ADC and Dslow than the ineffective group (all P<0.05). Tumor regression rate negatively correlated with MTD, Ktrans, Kep, and Dfast but positively correlated with ADC and Dslow. Receiver operating characteristic curve analysis suggested that the area under the curve of ADC, Dslow, Dfast, Ktrans, and Kep were 0.869, 0.833, 0.812, 0.802, and 0.809, respectively. In conclusion, these results suggest that quantitative DWI and PWI parameters might be useful in evaluating the efficacy of TACE in the treatment of HCC patients. [ABSTRACT FROM AUTHOR]

Background: The most common histological types of invasive breast carcinomas are the invasive ductal carcinoma (IDC) and the invasive lobular carcinoma (ILC). The purpose of our study was to evaluate the role of the diffusionweighted imaging (DWI) and the in vivo proton magnetic resonance spectroscopy (¹H-MRS) at 3 Tesla magnet in invasive breast cancer and correlate them with the dynamic contrast enhancement (DCE) and pathologic findings. Methods: We retrospectively studied at 3Tesla magnet the apparent diffusion coefficient (ADC) values, the detection of choline in the ¹H-MRS and the kinetic analyses obtained after DCE in 181 patients with histologically confirmed invasive breast carcinomas. Among these patients, 160 had IDC and 21 ILC. We used the DWI sequence with a b value of 1,000 mm2/sec for the calculation of the ADC value, the fat-suppressed point-resolved spectroscopy (PRESS) sequence in order to evaluate the existence of a choline peak in the spectrum and the T1W GRE FAT SAT VIBRANT sequence for the characterization of the kinetic curves. Finally, we correlated the pathologic type of invasive cancer, as well as the type of the kinetic curve with the ADC value and the detectability of choline resonance in the spectrum in each of the 181 patients. Results: The ADC values in the 158 out of 160 IDC patients, ranged from 0.5 x 10-3 to 1.2 x 10-3 mm²/sec, with 78.1 % having ADC value of 1 x 10-3 mm²/sec. Regarding the 1H-MRS, in 121 out of 160 IDC patients, choline was found in 72.3 %. The ADC values in the 21 ILC patients also ranged from 0.5 x 10-3 to 1.2 x 10-3 mm²/sec with 57.1 % having ADC value of 1 x 10-3 mm²/sec. Regarding the 1H-MRS, in 10 out of 21 ILC patients, detection of choline was positive in 60 % of them. In the 21 ILC patients, the kinetic analysis after the dynamic administration of contrast medium showed type I (persistent) curve in 4.3 %, type II (plateau) curve in 33.3 % and type III (washout) in 52.4 %. In the 158 IDC patients (missing in two cases) type I curve was obtained in 0.63 %, type II in 19.4 % and type III in 80 %. From the correlation analysis of the IDC results using Kruskal-Wallis Test and the non-parametric Kendall's tau-b test, the curve type was positively associated (Kendal tau-b: 0.254, p =0.005) with the presence of choline, while the ADC value was negatively associated (Kendal tau-b: -0.224, p =0.011) with the presence of choline. In the ILC cases, the sample was insufficient for the correlation to become statistically significant. However, the ADC values tended to be lower in IDC patients (78.1 % having ADC value 1 x 10-3 mm²/sec) compared to ILC (57.1 % having ADC value 1 x 10-3 mm²/sec). Choline was more commonly detected in the IDC (72.3 %) than ILC (60 %) patients. Conclusion: Our results are consistent with previous findings that both ADC values and choline detection in the spectrum play a significant role in establishing the final diagnosis of malignancy, especially when the kinetic pattern of enhancement is misleading. [ABSTRACT FROM AUTHOR]

Copyright of La Radiologia Medica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BSTRACT BACKGROUND AND PURPOSE [ABSTRACT FROM AUTHOR]

Clinical and radiological features of patients with unclear-onset stroke do not differ significantly from those with known-onset stroke. There is a lack of evidence for the safety and efficacy of thrombolysis in patients with unclear-onset stroke. We sought to provide supportive data on the safety and efficiency of thrombolysis in patients with unclear-onset stroke. We retrospectively identified patients with unclear-onset stroke (<3 h of first found abnormal time) from our stroke registry. We performed following protocols for thrombolysis in patients with unclear-onset stroke; initial conventional CT-based intravenous thrombolysis (IVT), repeat MRI during IVT, and then decision to maintain IVT or to perform combined intra-arterial thrombolysis. In addition, we compared clinical outcomes and safety between thrombolyzed and non-thrombolyzed patients. A total of 78 patients with unclear-onset stroke were included. Twenty-nine patients underwent thrombolysis. Thrombolysis (OR, 6.842; 95% CI, 1.950-24.004; P = 0.003) and baseline NIHSS (OR, 0.769; 95% CI, 0.645-0.917; P = 0.003) were associated with favorable outcomes at 3 months in multivariate logistic regression analysis. The frequency of hemorrhagic transformation and symptomatic ICH was not significantly different between the thrombolyzed and non-thrombolyzed patients (34.4% vs. 40.7% and 10.3% vs. 8.2%, respectively). The results of this study suggest that thrombolysis in unclear-onset stroke could be independently associated with favorable outcomes at 3 months and that thrombolysis based on repeat imaging appears to be safely applied to patients with unclear-onset stroke. Click to view the accompanying paper in this issue. [ABSTRACT FROM AUTHOR]

OBJECTIVE: • To evaluate the combination of multiple magnetic resonance imaging (MRI) techniques, including T2-weighted imaging (T2W), dynamic contrast-enhanced imaging (DCE) and diffusion-weighted imaging (DWI), for the detection and localization of prostate cancer. PATIENTS AND METHODS: • In all, 57 patients underwent endorectal MRI at 1.5 T before radical prostatectomy (RP) for localized prostate cancer. • On T2W images and histological wholemount analysis, the peripheral zone (PZ) and transition zone (TZ) were divided into upper and lower glands, as well as left and right halves, thus yielding four quadrants for each zone. • On histological analysis, the total number of tumour foci, their location and larger diameter were recorded. T2W alone, T2W + DWI, T2W + DCE and all three techniques combined were scored for the likelihood of tumour in each area and results were compared with whole-mount analysis. • The area under the receiver operating characteristic curve ( A z ) was used to evaluate accuracy for tumour detection. The association between MR accuracy and Gleason score was statistically assessed. RESULTS: • Of the 456 prostate octants analysed, 145 showed cancer on whole-mount analysis, 120 (83%) of them with a diameter assumed to correspond to a volume > 0.2 cm 3 . Gleason score was ≥ 7 in 68 (47%) tumours. • In the PZ, the A z value was significantly higher for T2W + DWI, T2W + DCE and all three techniques combined than for T2W alone ( P < 0.05). • In the TZ, the A z value was higher for T2W + DWI than for T2W alone, but the difference was not significant. • The A z value for T2W + DWI was significantly higher than that for T2W + DCE or for the three sequences combined. • Gleason score was significantly associated with cancer detection in the PZ. CONCLUSIONS: • Adding DWI and DCE to T2W imaging increased MRI performance in cancer detection in the PZ significantly. • However, this multiparametric model failed to improve performance in the TZ. • Gleason score significantly influenced cancer detection in the PZ but not in the TZ. [ABSTRACT FROM AUTHOR]

PURPOSE The characterization and differentiation of central nervous system (CNS) lymphoma has important diagnostic, therapeutic, and prognostic significance. The purpose of this study is to characterize the diffusion-weighted imaging (DWI) and MR spectroscopic (MRS) findings in CNS lymphoma. MATERIALS AND METHODS Twenty consecutive patients (male [ n= 12], female [ n= 8]) with histopathologically proven CNS lymphoma were retrospectively evaluated during this study from July 2005 to April 2007. Patients included immunocompromised ( n= 9) and immunocompetent ( n= 11) individuals. MR Imaging (pretreatment n= 13), pre- and post-treatment ( n= 7) included DWI ( n= 20) (b = 1000s/mm2) and ADC (apparent diffusion coefficient) maps of all patients. MRS was performed ( n= 10) with PRESS (point-resolved spectroscopy) sequence (multivoxel n= 8, single voxel n= 2) with a TE of 144 msec. All patients were histopathologically confirmed to have lymphoma by biopsy. RESULTS Areas of restricted diffusion were observed in 90 % ( n= 18/20) on pretreatment scans. The diffusion restriction was variable on post-treatment scans. Median metabolite ratios in 10 patients were Cho/Cr- 2.12, NAA/Cho - .49, and NAA/Cr - 1.64. Presence of lactate or lipid was noted in 90 % ( n= 9/10). Sites of lesion location were subcortical white matter ( n= 6), basal ganglia ( n= 4), corpus callosum ( n= 3), extra-axial space including cavernous sinus ( n= 5), cerebellum ( n= 1), and lateral ventricle ( n= 1). CONCLUSION Restricted diffusion is a consistent imaging finding in CNS lymphoma in immunocompetent patients. Spectroscopy is helpful in initial imaging diagnosis and post-treatment surveillance. These lesions are usually paraventricular in location. MR imaging appearances differ among immunocompetent and immunosuppressed individuals in most cases. [ABSTRACT FROM AUTHOR]

We studied four patients with diabetes mellitus and chronic renal failure who developed sudden choreic movement disorders. The clinical manifestations, laboratory findings, MR imaging findings, and clinical outcome in each patient were evaluated. All four patients had long-term diabetes mellitus and severe azotaemia. Brain MR findings consisted of bilateral symmetric basal ganglia lesions, with decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. All three patients who underwent diffusion-weighted MR imaging (DWI) showed signal intensities similar to those of the surroundings in regions corresponding to increased signal intensity on T2-weighted images, with slightly increased apparent diffusion coefficient (ADC) values. Two of the patients showed small focal areas of restricted diffusion within the basal ganglia lesions. After haemodialysis, follow-up MR imaging in all patients demonstrated that the basal ganglia lesions had regressed markedly, with some residual changes. The movement disorders also improved in all patients. A syndrome associated with acute bilateral basal ganglia lesions in diabetic uraemic patients is rare, with reversible changes demonstrated by clinical and imaging findings. DWI showed that the bilateral basal ganglia lesions in this syndrome were primarily vasogenic in origin, although there were small foci of cytotoxic oedema within the lesions. [ABSTRACT FROM AUTHOR]

Due to its complementary information to standard morphological imaging, functional renal magnetic resonance imaging is a rapid growing field of radiology. This pictorial essay provides a comprehensive overview of state-of-the-art functional renal imaging techniques including renal magnetic resonance angiography, first pass renal perfusion, assessment of renal function, blood-oxygen level dependent imaging of the kidneys and diffusion-weighted imaging of the kidneys including diffusion-tensor imaging of the kidneys. Basic technical concepts for all sequences are laid out. As renal perfusion imaging becomes a clinical routine examination, particular attention is given to renal perfusion measurements and the potential postprocessing approaches. Advantages and drawbacks of the published methods are illustrated. Future applications of functional renal imaging are presented. [ABSTRACT FROM AUTHOR]

We examined MRI of two patients with progressive multifocal leukoencephalopathy (PML), including diffusion-weighted imaging (DWI), with calculation of apparent diffusion coefficients (ADC). The pathology findings of one patient were compared with those of MRI. The lesions had different ADC and DWI appearances, depending on the stage of the disease. Newer lesions and the advancing edge of large lesions had normal-to-low ADC and gave high signal on DWI. Older lesions and the centre of large lesions had increased ADC and gave low signal. High signal on DWI and low ADC mark the regions of active infection and cell swelling, distinguishing them from areas of reparative gliosis. [ABSTRACT FROM AUTHOR]