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Abstract We developed artificial intelligence models to predict the brain metastasis (BM) treatment response after stereotactic radiosurgery (SRS) using longitudinal magnetic resonance imaging (MRI) data and evaluated prediction accuracy changes according to the number of sequential MRI scans. We included four sequential MRI scans for 194 patients with BM and 369 target lesions for the Developmental dataset. The data were randomly split (8:2 ratio) for training and testing. For external validation, 172 MRI scans from 43 patients with BM and 62 target lesions were additionally enrolled. The maximum axial diameter (Dmax), radiomics, and deep learning (DL) models were generated for comparison. We evaluated the simple convolutional neural network (CNN) model and a gated recurrent unit (Conv-GRU)-based CNN model in the DL arm. The Conv-GRU model performed superior to the simple CNN models. For both datasets, the area under the curve (AUC) was significantly higher for the two-dimensional (2D) Conv-GRU model than for the 3D Conv-GRU, Dmax, and radiomics models. The accuracy of the 2D Conv-GRU model increased with the number of follow-up studies. In conclusion, using longitudinal MRI data, the 2D Conv-GRU model outperformed all other models in predicting the treatment response after SRS of BM.

Background and Objectives Sternberg’s canal is known to result from incomplete fusion of bony compartments constituting the sphenoid bone during the developmental process. This study aimed to evaluate the prevalence and clinical implications of Sternberg’s canal. Methods A retrospective review of patients over the age of 18 years who had undergone endoscopic sinus surgery from 2014 to 2019 at a single institution was performed. Patients (n=98) were categorized into those with sphenoid fungal ball (SFB) (n=39), those with primary chronic rhinosinusitis (CRS) (n=39), and controls (n=20) and were evaluated radiologically. A small pit in the lateral wall, located medial to the maxillary division of the trigeminal nerve (V2), in front of the opticocarotid recess was regarded as Sternberg’s canal. Children under the age of 12 years (n=39) without any sinus disease were also evaluated to determine the prevalence of Sternberg’s canal in the pediatric population. Results Patients with SFB showed the highest prevalence of Sternberg’s canal (56.4%), followed by those with CRS (20.5%) and controls (10.0%) (p

Abstract Accurate and reliable detection of intracranial aneurysms is vital for subsequent treatment to prevent bleeding. However, the detection of intracranial aneurysms can be time-consuming and even challenging, and there is great variability among experts, especially in the case of small aneurysms. This study aimed to detect intracranial aneurysms accurately using a convolutional neural network (CNN) with 3D time-of-flight magnetic resonance angiography (TOF-MRA). A total of 154 3D TOF-MRA datasets with intracranial aneurysms were acquired, and the gold standards were manually drawn by neuroradiologists. We also obtained 113 subjects from a public dataset for external validation. These angiograms were pre-processed by using skull-stripping, signal intensity normalization, and N4 bias correction. The 3D patches along the vessel skeleton from MRA were extracted. Values of the ratio between the aneurysmal and the normal patches ranged from 1:1 to 1:5. The semantic segmentation on intracranial aneurysms was trained using a 3D U-Net with an auxiliary classifier to overcome the imbalance in patches. The proposed method achieved an accuracy of 0.910 in internal validation and external validation accuracy of 0.883 with a 2:1 ratio of normal to aneurysmal patches. This multi-task learning method showed that the aneurysm segmentation performance was sufficient to be helpful in an actual clinical setting.

Abstract Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignancy that transforms from PA. Early detection of the carcinoma by biopsy is difficult due to similar histopathology of the malignant and benign components. To address this, we investigated and compared the characteristic miRNA expression patterns across samples of the PA, carcinomatous portions (CA) of CXPA, as well as conventional PA. We selected 13 CXPA and 16 conventional PA FFPE samples, separated the PA and CA portions of CXPA samples and conducted miRNA profiling for each group. Among 13 transcripts that were differentially expressed between PA and CA of CXPA, eight miRNAs were up-regulated and five down-regulated in CA. Bioinformatic analysis revealed that the up-regulated miRNAs were related to cancer progression and down-regulated ones to tumor suppression. Additionally, seven miRNAs were significantly up-regulated in PA of CXPA compared to conventional PA, although they are histopathologically similar. Almost all of these transcripts interacted with TP53, a well-known tumor suppressor. In conclusion, we identified differentially expressed miRNAs in PA and CA of CXPA, which were closely associated with TP53 and various cancer-related pathways. We also identified differentially expressed miRNAs in the PA of CXPA and conventional PA which may serve as potential biomarkers.

Abstract Determining the etiology of severe-to-profound sensorineural hearing loss (SP-SNHL) in pediatric subjects is particularly important in aiding the decision for auditory rehabilitation. We aimed to update the etiologic spectrum of pediatric SP-SNHL by combining internal auditory canal (IAC)-MRI with comprehensive and state-of-the-art genetic testings. From May 2013 to September 2020, 119 cochlear implantees under the age of 15 years with SP-SNHL were all prospectively recruited. They were subjected to genetic tests, including exome sequencing, and IAC-MRI for etiologic diagnosis. Strict interpretation of results were made based on ACMG/AMP guidelines and by an experienced neuroradiologist. The etiology was determined in of 65.5% (78/119) of our cohort. If only one of the two tests was done, the etiologic diagnostic rate would be reduced by at least 21.8%. Notably, cochlear nerve deficiency (n = 20) detected by IAC-MRI topped the etiology list of our cohort, followed by DFNB4 (n = 18), DFNB1 (n = 10), DFNB9 (n = 10) and periventricular leukomalacia associated with congenital CMV infection (n = 8). Simultaneous application of state-of-the-art genetic tests and IAC-MRI is essential for etiologic diagnosis, and if lesions of the auditory nerve or central nerve system are carefully examined on an MRI, we can identify the cause of deafness in more than 65% of pediatric SP-SNHL cases.

Parkinson’s disease (PD) is a movement disorder that develops due to degenerative loss of dopaminergic cells in the substantia nigra of the midbrain. Recent advances in MRI techniques have demonstrated various imaging findings that can reflect the underlying pathophysiological processes occurring in Parkinson’s disease. Many imaging studies have shown that such findings can assist in the diagnosis of Parkinson’s disease and its differentiation from atypical parkinsonism. In this review, we present MRI techniques that can be used in clinical assessment, such as nigrosome imaging and neuromelanin imaging, and we provide the detailed imaging features of Parkinson’s disease reflecting nigrostriatal degeneration.

Abstract Temporalis muscle thickness (TMT) on brain magnetic resonance imaging (MRI) is correlated with sarcopenia and can be a predictive marker for survival in patients with brain tumors, but the association of TMT on head and neck computed tomography (CT) with survival in head and neck squamous cell carcinoma (HNSCC) remains unclear. We investigated whether TMT on CT could predict progression-free survival (PFS) in patients with HNSCC. A total of 106 patients with newly diagnosed HNSCC were included in this retrospective study. The patients underwent baseline head and neck CT and/or MRI between July, 2008 and August, 2018. The correlation between TMT on CT and MRI was tested using intraclass correlation coefficient (ICC). The cut-off value of TMT on CT for determining tumor progression was identified using receiver-operating characteristic curve analysis. Uni- and consecutive multi-variable Cox regression models were used to verify the association between TMT and PFS. TMT on CT and MRI showed excellent correlation (ICC, 0.894). After a mean follow-up of 37 months, 49 out of 106 patients showed locoregional recurrence and/or distant metastasis. The cut-off TMT of 6.47 mm showed good performance in predicting tumor progression (area under the curve, 0.779). The Cox regression model showed that TMT ≤ 6.24 mm (median value in study population) was a significant contributing factor for predicting shorter PFS (hazard ratio 0.399; 95% confidence interval 0.209–0.763; P = .005). TMT may be used as a surrogate parameter for pre-treatment sarcopenia and could help predict PFS in patients with HNSCC.

Abstract Autoimmune and autoinflammatory inner ear diseases (AIED/AID) are characterized by the symptom of sensorineural hearing loss (SNHL). To date, standardized diagnostic tools for AIED/AID are lacking, and clinically differentiating AIED/AID from chronic otitis media (COM) with SNHL is challenging. This retrospective study aimed to construct a magnetic resonance imaging (MRI)-based decision tree using classification and regression tree (CART) analysis to distinguish AIED/AID from COM. In total, 67 patients were enrolled between January 2004 and October 2019, comprising AIED/AID (n = 18), COM (n = 24), and control groups (n = 25). All patients underwent 3 T temporal bone MRI, including post-contrast T1-weighted images (postT1WI) and post-contrast FLAIR images (postFLAIR). Two radiologists evaluated the presence of otomastoid effusion and inner ear contrast-enhancement on MRI. A CART decision tree model was constructed using MRI features to differentiate AIED/AID from COM and control groups, and diagnostic performance was analyzed. High-intensity bilateral effusion (61.1%) and inner ear enhancement (postFLAIR, 93.8%; postT1WI, 61.1%) were the most common findings in the AIED/AID group. We constructed two CART decision tree models; the first used effusion amount as the first partitioning node and postT1WI-inner ear enhancement as the second node, whereas the second comprised two partitioning nodes with the degree of postFLAIR-enhancement of the inner ear. The first and second models enabled distinction of AIED/AID from COM with high specificity (100% and 94.3%, respectively). The amount of effusion and the degree of inner ear enhancement on MRI may facilitate the distinction between AIED/AID and COM with SNHL using decision tree models, thereby contributing to early diagnosis and intervention.

Abstract Surgical plugging to treat superior semicircular canal dehiscence (SCD) has been proven to impede the effect of the third mobile window, abating cochleovestibular symptoms. Knowledge of superior semicircular canal (SC)-plugging status has been proposed to serve as a guide for adjuvant treatment. Here, we investigated disturbances in the inner ear fluid space following SC plugging using a novel three-dimensional (3D) reconstruction-based method. This approach used a semi-automatic segmentation algorithm and a direct volume rendering method derived from conventional magnetic resonance images. The variable extents of filling defects at the sites of SC plugging and the positional relation of the defect to the ampulla and common crus were identified. The success group exhibited markedly reduced volumes following surgery, whereas the failure group displayed no changes in volume. These results indicate that the success or failure of SC plugging was related to 3D volume changes in the labyrinth fluid signal. Collectively, this study presents individualized SC-plugging statuses using a novel 3D reconstruction-based method and it facilitates future work regarding easy-to-measure 3D volume changes. This current technology also aids in the exploration of pathologic changes in various targets of interest.

A clinical diagnosis of Ménière's disease (MD) is made based on medical history and audiometry findings. The 1995 American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines requires histopathological confirmation of endolymphatic hydrops (EH) for a diagnosis of “certain” MD. Symptoms such as dizziness and ear fullness are important diagnostic features; however, the descriptions provided by patients are frequently vague and non-specific. A recently developed magnetic resonance imaging (MRI) protocol to document EH is, therefore, useful for the evaluation of inner ear status in patients with MD. In this study, patients with MD were assessed using MRI and the HYDROPS (HYbriD of Reversed image Of Positive endolymph signal and native image of positive perilymph Signal) protocol to investigate the effectiveness of MRI for visualization of the endolymphatic space in the diagnosis of MD by correlating clinical laboratory parameters with the grade of EH. Of the 123 patients with MD recruited in this study, 80 had definite MD, 11 had probable MD, and 32 had possible MD based on the 1995 AAO-HNS guidelines. The EH grade based on HYDROPS MRI was determined independently by two otorhinolaryngologists and compared with several clinical parameters, including the diagnostic scale of MD (1995 AAO-HNS guidelines), pure tone average (PTA), low tone average (LTA), canal paresis (CP) on the caloric test, and disease duration. Cochlear hydrops and vestibular hydrops were detected in 58 and 80% of 80 definite MD ears, in 33 and 58% of 12 probable MD ears, and in 5 and 27% of 37 possible MD ears, respectively. The proportion of higher hydrops grades increased significantly with grade according to the MD diagnostic scale (p < 0.0001). Both PTA and LTA were significantly higher in patients with hydrops grade 2 than hydrops grade 0 in both the cochlea and the vestibule. CP was significantly higher in patients with grade 2 than grade 0 vestibular hydrops. Disease duration was not associated with hydrops grade. Radiological evaluation of MD using the HYDROPS protocol is useful for evaluation of the extent and severity of EH in the diagnosis of MD based on its pathophysiological mechanism.

BackgroundThe glymphatic system has been described as one that facilitates the exchange between the cerebrospinal fluid (CSF) and interstitial fluid, and many recent studies have demonstrated glymphatic flow based on magnetic resonance imaging (MRI). We aim to systematically review the studies demonstrating a normal glymphatic flow in a human population using MRI and to propose a detailed glymphatic imaging protocol.MethodsWe searched the MEDLINE and EMBASE databases to identify studies with human participants involving MRI-based demonstrations of the normal glymphatic flow. We extracted data on the imaging sequence, imaging protocol, and the targeted anatomical structures on each study.ResultsAccording to contrast-enhanced MRI studies, peak enhancement was sequentially detected first in the CSF space, followed by the brain parenchyma, the meningeal lymphatic vessel (MLV), and, finally, the cervical lymph nodes, corresponding with glymphatic flow and explaining the drainage into the MLV. Non-contrast flow-sensitive MRI studies revealed similar glymphatic inflow from the CSF space to the brain parenchyma and efflux of exchanged fluid from the brain parenchyma to the MLV.ConclusionWe may recommend T1-weighted contrast-enhanced MRI for visualizing glymphatic flow. Our result can increase understanding of the glymphatic system and may lay the groundwork for establishing central nervous system fluid dynamic theories and developing standardized imaging protocols.

Abstract The present study assessed test–retest and inter-observer reliability of diffusion tensor imaging (DTI) in cervical spondylotic myelopathy (CSM), as well as the agreement among measurement methods. A total 34 patients (12 men, 22 women; mean age, 58.7 [range 45–79] years) who underwent surgical decompression for CSM, with pre-operative DTI scans available, were retrospectively enrolled. Four observers independently measured fractional anisotropy (FA) values twice, using three different measurement methods. Test–retest and inter-observer reliability was assessed using intraclass correlation coefficients (ICCs). Overall, inter-observer agreements varied according to spinal cord level and the measurement methods used, and ranged from poor to excellent agreement (ICC = 0.374–0.821), with relatively less agreement for the sagittal region of interest (ROI) method. The radiology resident and neuro-radiologist group showed excellent test–retest reliability at almost every spinal cord level (ICC = 0.887–0.997), but inter-observer agreements varied from fair to good (ICC = 0.404–0.747). Despite excellent test–retest reliability of the ROI measurements, FA measurements in patients with CSM varied widely in terms of inter-observer reliability. Therefore, DTI parameter data should be interpreted carefully when applied clinically.

Abstract Background Although oropharyngeal squamous cell carcinoma (OPSCC) with human papillomavirus (HPV) infection has a good prognosis, the accurate prediction of survival and risk of treatment failure is essential to design deintensification regimens. Here, we investigated estrogen receptor α (ERα) as a prognostic biomarker with therapeutic implications in OPSCC alongside factors associated with HPV infection. Methods We performed immunohistochemistry for ERα and p53 using formalin-fixed, paraffin-embedded tissues and assessed the HPV status using p16 immunohistochemistry and HPV DNA testing in 113 consecutive patients with OPSCC treated with surgical resection or radiotherapy/chemoradiotherapy. Results ERα expression and p53 alteration was observed in 35.4% and 21.2% OPSCCs; 45.6% and 1.3% p16+/HPV+ OPSCCs; and 11.5% and 76.9% p16− OPSCCs, respectively. These data suggest that OPSCC pathogenesis varies with HPV status. Furthermore, ERα expression was associated with improved overall survival (OS) in both HPV+ (p16+/HPV+ OPSCC) and p16+ (p16+ OPSCC irrespective of HPV status) models (p = 0.005 and p = 0.006, respectively) and with improved OS adjusted for stage (p = 0.037, hazard ratio: 0.109, 95% confidence interval 0.013–0.871) in the p16+ model. Conclusions ERα is a potential predictive biomarker for improved survival in both HPV+ and p16+ OPSCC models.

Objectives Vertebrobasilar dolichoectasia (VBD), an elongation and distension of vertebrobasilar artery, may present with cranial nerve symptoms due to nerve root compression. The objectives of this study are to summarize vestibulocochlear manifestations in subjects with VBD through a case series and to discuss the needs of thorough oto-neurotologic evaluation in VBD subjects before selecting treatment modalities. Methods Four VBD subjects with vestibulocochlear manifestations were reviewed retrospectively. VBD was confirmed by either brain or internal auditory canal magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). Patient information, medical history, MRI/MRA findings, and audiometry or vestibular function tests were reviewed according to patient’s specific symptom. Results Of the four subjects, three presented with ipsilesional sensorineural hearing loss (SNHL), three with paroxysmal recurrent vertigo, and two with typewriter tinnitus. The MRI/MRA of the four subjects revealed unilateral VBD with neurovascular compression of cisternal segment or the brainstem causing displacement, angulation, or deformity of the cranial nerve VII or VIII that corresponded to the symptoms. Conclusion Vestibulocochlear symptoms such as SNHL, recurrent paroxysmal vertigo, or typewriter tinnitus can be precipitated from a neurovascular compression of the vestibulocochlear nerve by VBD. Because proper medical or surgical treatments may stop the disease progression or improve audio-vestibular symptoms in subjects with VBD, a high index of suspicion and meticulous radiologic evaluation are needed when vestibulocochlear symptoms are not otherwise explainable, and if VBD is confirmed to cause audiovestibular manifestation, a thorough oto-neurotologic evaluation should be performed before initial treatment.

Objectives This study aimed to evaluate the clinical characteristics of maxillary sinus fungus ball (MFB) to increase the preoperative diagnostic accuracy. Methods A retrospective review of 247 patients who underwent endoscopic sinus surgery for unilateral maxillary sinusitis from January 2015 to December 2017 at a single institution was performed. Patients with pathologically proven MFB were compared to those with unilateral chronic maxillary sinusitis (CMS). Patient demographics and computed tomography (CT) findings were evaluated. The CT features were categorized as intralesional hyperdensity (calcification), the irregular lobulated protruding lesion (fuzzy appearance), maxillary sinus full haziness without mass effect, maxillary sinus full haziness with mass effect, and others. A regression tree analysis was performed. Results In total, 247 patients were analyzed; among them, 179 (72.5%) had MFB and 68 (27.5%) had CMS. MFB showed predominance in older individuals. Among the radiological features, intralesional hyperdensity was most commonly associated with MFB. The presence of a fuzzy appearance or full opacity with mass effect was also associated with MFB. The highest area under the curve was noted with the regression tree analysis based on the model, which included the presence of intralesional hyperdensity, demographic data (age), and presence of fuzzy appearance or maxillary sinus full haziness with mass effect in case of absence of intralesional hyperdensity (0.904). Conclusion A simple algorithm to optimize the preoperative diagnosis of MFB was developed. Physicians should be aware of such findings in the management of patients presenting with unilateral CMS.

Purpose To describe magnetic resonance imaging (MRI) findings in 10 cases of Toxocara canis myelitis and to analyze these findings to aid in the diagnosis of this condition. Materials and Methods From June 2015 to March 2018, we retrospectively analyzed the electronic medical records and MR images of patients who were diagnosed with Toxocara canis myelitis. The analysis of the MR images was based on a discussion between an experienced spinal radiologist and a radiology resident. Results This study classified MRI findings into the following two types. Type 1 was defined as central and diffuse T2 high signal intensity on the axial plane, which was observed in 50% of all cases. All lesions showed avid enhancement, mostly in the posterolateral or posterior region (4 cases, 80%). Type 2 was defined as wedge-shaped or focal T2 high signal intensity in the posterolateral or posterior region and corresponded to the remaining 50% of the cases. In this case, the extent of the lesion was relatively small and contrast enhancement was observed in only one case. Conclusion This study revealed that various imaging findings could be observed in cases of Toxocara canis myelitis, and the findings were classified into two types.

BackgroundAlthough accurate treatment response assessment for brain metastases (BMs) is crucial, it is highly labor intensive. This retrospective study aimed to develop a computer-aided detection (CAD) system for automated BM detection and treatment response evaluation using deep learning.MethodsWe included 214 consecutive MRI examinations of 147 patients with BM obtained between January 2015 and August 2016. These were divided into the training (174 MR images from 127 patients) and test datasets according to temporal separation (temporal test set #1; 40 MR images from 20 patients). For external validation, 24 patients with BM and 11 patients without BM from other institutions were included (geographic test set). In addition, we included 12 MRIs from BM patients obtained between August 2017 and March 2020 (temporal test set #2). Detection sensitivity, dice similarity coefficient (DSC) for segmentation, and agreements in one-dimensional and volumetric Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria between CAD and radiologists were assessed.ResultsIn the temporal test set #1, the sensitivity was 75.1% (95% confidence interval [CI]: 69.6%, 79.9%), mean DSC was 0.69 ± 0.22, and false-positive (FP) rate per scan was 0.8 for BM ≥ 5 mm. Agreements in the RANO-BM criteria were moderate (κ, 0.52) and substantial (κ, 0.68) for one-dimensional and volumetric, respectively. In the geographic test set, sensitivity was 87.7% (95% CI: 77.2%, 94.5%), mean DSC was 0.68 ± 0.20, and FP rate per scan was 1.9 for BM ≥ 5 mm. In the temporal test set #2, sensitivity was 94.7% (95% CI: 74.0%, 99.9%), mean DSC was 0.82 ± 0.20, and FP per scan was 0.5 (6/12) for BM ≥ 5 mm.ConclusionsOur CAD showed potential for automated treatment response assessment of BM ≥ 5 mm.

Purpose Although endovascular treatment is currently thought to only be suitable for patients who have pial arterial filling scores >3 as determined by multiphase computed tomography angiography (mpCTA), a cut-off score of 3 was determined by a study, including patients within 12 hours after symptom onset. We aimed to investigate whether a cut-off score of 3 for endovascular treatment within 6 hours of symptom onset is an appropriate predictor of good functional outcome at 3 months. Materials and Methods From April 2015 to January 2016, acute ischemic stroke patients treated with mechanical thrombectomy within 6 hours of symptom onset were enrolled into this study. Pial arterial filling scores were semi-quantitatively assessed using mpCTA, and clinical and radiological parameters were compared between patients with favorable and unfavorable outcomes. Multivariate logistic regression analysis was then performed to investigate the independent association between clinical outcome and pial collateral score, with the predictive power of the latter assessed using C-statistics. Results Of the 38 patients enrolled, 20 (52.6%) had a favorable outcome and 18 had an unfavorable outcome, with the latter group showing a lower mean pial arterial filling score (3.6±0.8 vs. 2.4±1.2, P=0.002). After adjusting for variables with a P-value of 2 vs. ≤2. Conclusion A pial arterial filling cut-off score of 2 as determined by mpCTA appears to be more suitable for predicting clinical outcomes following endovascular treatment within 6 hours of symptom onset than the cut-off of 3 that had been previously suggested.

Background and Purpose: This systematic review and meta-analysis aimed to evaluate the pooled proportion of image findings of acute to subacute craniocervical arterial dissection (AD) direct signs on magnetic resonance vessel wall imaging (MR-VWI) and to identify factors responsible for the heterogeneity across the included studies.Methods: A systematic literature search in the Ovid-MEDLINE and EMBASE databases was performed for studies published on the relevant topic before April 14, 2020. Pooled sensitivity and specificity values and their 95% confidence intervals (CIs) were calculated using bivariate random-effects modeling. Meta-regression analyses were also performed to determine factors influencing heterogeneity.Results: Eleven articles with data for 209 patients with acute to subacute craniocervical AD who underwent MR-VWI were included in this systematic review and meta-analysis. The most common findings on MR-VWI were wall hematoma (84%; 95% CI, 71%−92%), abnormal enhancement (72%; 95% CI, 49%−88%), aneurysmal dilatation (71%, 95% CI, 53%−84%), and intimal flap or double lumen signs (49%; 95% CI, 29%−71%). Among the potential covariates of heterogeneity, the presence of contrast-enhanced T1-weighted imaging (CE-T1WI) within the MR-VWI sequence combination significantly affected the pooled proportion of the intimal flap or double lumen signs.Conclusion: Wall hematoma and intimal flap or double lumen signs were the most common and least common direct sign image findings, respectively, on MR-VWI in patients with acute to subacute craniocervical AD. Furthermore, the absence of CE-T1WI in MR-VWI protocol was the cause of heterogeneity for the detection of the intimal flap or double lumen signs. This data may help improve MR-VWI interpretation and enhance the understanding of the radiologic diagnosis of craniocervical AD.

ObjectivesTo determine the optimal utility of the open mouth maneuver and Metal Artifact Reduction for the Orthopedic Implants (O-MAR) technique for CT of the oral cavity and oropharynx.MethodsBetween July 2017 and May 2019, 59 subjects who underwent both conventional and open mouth head and neck CT scans were included in this retrospective study. All images were reconstructed using the O-MAR algorithm. With conventional CT with/without the O-MAR (CTc_O/CTc) and open mouth CT with/without O-MAR (CTo_O/CTo), one reader measured the noise level in multiple anatomic regions of the oral cavity and oropharynx. Visual scores for the streak artifact and overall subjective image quality were assessed by two independent readers.ResultsFor the mobile tongue, retromolar trigone, and palatine tonsil, the mean noise was significantly lower, and the mean visual scores were significantly higher, with CTo than with CTc or CTc_O (all, P < 0.001). The mean visual scores were higher with CTo_O than with CTo for the mobile tongue and palatine tonsil (all, P < 0.001). Contrarily, for the mouth floor and tongue base, the mean noise was significantly higher with CTo_O than with CTc or CTc_O, and the mean visual scores were significantly higher with CTc than with CTo or CTo_O (all, P < 0.001).ConclusionsThe open mouth maneuver and O-MAR technique can have different influences on the CT image quality according to the anatomical subsites of the oral cavity and oropharynx.

Superior semicircular canal dehiscence (SCD), which is characterized by a “third mobile window” in the inner ear, causes various vestibular and auditory symptoms and signs. Surgical plugging of the superior semicircular canal (SC) can eliminate the symptoms associated with increased perilymph mobility due to the presence of the third window. However, the natural course of vestibular function after surgical plugging remains unknown. Therefore, we explored longitudinal vestibular function after surgery in 11 subjects with SCD who underwent SC plugging using the middle cranial fossa approach. Changes in vestibulo-ocular reflex (VOR) gain in all planes were measured over 1 year with the video head impulse test. We also evaluated surgical outcomes, including changes in symptoms, audiometric results, and electrophysiological tests, to assess whether plugging eliminated third mobile window effects. The mean VOR gain for the plugged SC decreased from 0.81 ± 0.05 before surgery to 0.65 ± 0.08 on examinations performed within 1 week after surgery but normalized thereafter. Four of seven subjects who were able to perform both VOR tests before surgery and immediately after surgery had pathologic values (SC VOR gain < 0.70). Conversely, the mean VOR gain in the other canals remained unchanged over 1 year. The majority of symptoms and signs were absent or markedly decreased at the last follow-up evaluation, and no complications associated with the surgery were reported. Surgical plugging significantly attenuated the air-bone gap, in particular at low frequencies, because of increased bone conduction thresholds and deceased air conduction thresholds. Moreover, surgical plugging significantly increased vestibular-evoked myogenic potential thresholds and decreased the ratio of summating potential to action potential in plugged ears. Postoperative heavily T2-weighted images were available for two subjects and showed complete obliteration of the T2-bright signal intensity in the patent SC lumen in preoperative imaging based on filling defect at the site of plugging. Our results suggest that successful plugging of dehiscent SCs is closely associated with a transient, rather than persistent, disturbance of labyrinthine activity exclusively involved in plugged SCs, which may have clinical implications for timely and individualized vestibular rehabilitation.

Granulomatosis with polyangiitis (GPA) can involve the skull base or the Eustachian tubes. GPA is diagnosed on the basis of clinical manifestations and serological tests, although it is challenging to discriminate GPA from infectious processes driving skull base osteomyelitis (SBO) and malignant processes such as nasopharyngeal carcinoma (NPC). Moreover, current serological tests have a low sensitivity and cannot distinguish GPA from these other conditions. We hypothesized that certain MRI characteristics would differ significantly among conditions and aimed to evaluate whether the features could differentiate between GPA, SBO, and NPC involving the skull base. We retrospectively evaluated the MRI findings of patients with GPA, SBO, and NPC. We performed univariable logistic regression analyses to identify the predictive variables for differentiating between conditions and evaluated their diagnostic values. We showed, for the first time, that certain MRI findings significantly differed between patients with GPA and those with SBO or NPC, including the lesion morphology and extent, the apparent diffusion coefficient (ADC) values, the contrast enhancement patterns, the presence or absence of necrosis, and retropharyngeal lymphadenopathy. In conclusion, utilizing certain MRI features can improve the diagnostic performance of MRI by differentiating GPA with skull base involvement from other conditions with similar radiologic findings, including SBO and NPC, facilitating treatment plans and, thus, improving patient outcomes.

Abstract Although neurovascular compression of the cochlear nerve (NVC-C) presenting as typewriter tinnitus is a discrete disease category, verified diagnostic criteria are lacking. We sought to refine the diagnostic criteria for NVC-C by reference to a relatively large case series. The medical records of 22 NVC-C patients were retrospectively reviewed. Psychoacoustic characteristics, the results of diagnostic work-up (including audiovestibular neurophysiological tests and radiological evaluations), and the initial treatment response to carbamazepine were investigated. All subjects described their tinnitus as a typical “typewriter” or “staccato” sound. Of the 22 subjects, 11 (50%) had histories of vertiginous spells, but none had ipsilesional hearing loss. Vestibular function tests in 11 subjects tested revealed only 2 (18.2%) isolated cervical vestibular evoked myogenic potential abnormalities. Radiological comparisons of the symptomatic and asymptomatic sides, regarding the type of the vascular loop and neurovascular contact, revealed no significant differences. However, all 22 subjects exhibited immediate and marked responses to short-term carbamazepine treatment. Meticulous history-taking in terms of the psychoacoustic characteristics and the response to initial carbamazepine, are more reliable diagnostic clues than are radiological or neurophysiological data in NVC-C subjects. Therefore, the typical psychoacoustic characteristics and the response to initial carbamazepine should be included in the diagnostic criteria.

Objectives: The aim of this study was to delineate the clinical and laboratory features suggestive of intralabyrinthine schwannoma (ILS).Methods: We compared the clinical features of 16 patients with ILS, who had been diagnosed at the Seoul National University Bundang Hospital from 2003 to 2018, with those of 18 patients with symptomatic unilateral intracanalicular schwannoma and randomly selected 20 patients with definite or probable unilateral Meniere's disease (MD).Results: Patients with ILS presented with either recurrent spontaneous dizziness/vertigo combined with auditory symptoms (n = 8), isolated auditory symptoms without dizziness/vertigo (n = 7), or recurrent spontaneous dizziness/vertigo without auditory symptoms (n = 1). Most patients reported no improvement (n = 11) or worsening (n = 1) of the symptoms despite medical treatments including intratympanic (n = 5) or intravenous steroids (n = 2). Conventional brain MRIs failed to detect ILS in about a half of the patients (7/16, 44%). However, ILS showed a filling defect on 3-dimensional (3D) heavily T2-weighted MRIs (n = 12), and nodular enhancement on 3D contrast-enhanced T1 (n = 15) or FLAIR MRIs (n = 13) targeted for the inner ear. Compared to MD or intracanalicular schwannoma, ILS showed mostly abnormal head-impulse tests (HITs, p = 0.001). In contrast, the incidence of canal paresis did not differ among the groups (p = 0.513).Conclusion: ILS may mimic MD by presenting recurrent dizziness/vertigo and auditory symptoms. ILS should be suspected in patients with recurrent audiovestibulopathy especially when (1) the duration of the dizziness is not typical for MD, (2) the patients do not respond to medical treatments, or (3) HITs are abnormal.

Accurate image interpretation of Waters’ and Caldwell view radiographs used for sinusitis screening is challenging. Therefore, we developed a deep learning algorithm for diagnosing frontal, ethmoid, and maxillary sinusitis on both Waters’ and Caldwell views. The datasets were selected for the training and validation set (n = 1403, sinusitis% = 34.3%) and the test set (n = 132, sinusitis% = 29.5%) by temporal separation. The algorithm can simultaneously detect and classify each paranasal sinus using both Waters’ and Caldwell views without manual cropping. Single- and multi-view models were compared. Our proposed algorithm satisfactorily diagnosed frontal, ethmoid, and maxillary sinusitis on both Waters’ and Caldwell views (area under the curve (AUC), 0.71 (95% confidence interval, 0.62–0.80), 0.78 (0.72–0.85), and 0.88 (0.84–0.92), respectively). The one-sided DeLong’s test was used to compare the AUCs, and the Obuchowski–Rockette model was used to pool the AUCs of the radiologists. The algorithm yielded a higher AUC than radiologists for ethmoid and maxillary sinusitis (p = 0.012 and 0.013, respectively). The multi-view model also exhibited a higher AUC than the single Waters’ view model for maxillary sinusitis (p = 0.038). Therefore, our algorithm showed diagnostic performances comparable to radiologists and enhanced the value of radiography as a first-line imaging modality in assessing multiple sinusitis.

The use of gas-filled microbubbles in perfusion monitoring as intravascular ultrasound contrast agents has recently become more common. Additionally, microbubbles are employed as carriers of pharmaceutical substances or genes. Microbubbles have great potential to improve the delivery of therapeutic materials into cells and to modify vascular permeability, causing increased extravasation of drugs and drug carriers. Prostate cancer is the most common neoplasm in Europe and America, with an incidence twice to three times that of lung and colorectal cancer. Its incidence is still rising in Asian countries, including Japan and Korea. In this review, we present current strategies regarding the synthesis of microbubbles with targeted ligands on their surfaces, with a focus on prostate cancer.

Purpose Parallel imaging mitigates susceptibility artifacts that can adversely affect diffusion tensor tractography (DTT) of the pons depending on the reduction (R) factor. We aimed to find the optimal R factor for DTT of the pons that would allow us to visualize the largest possible number of pyramidal tract fibers. Materials and Methods Diffusion tensor imaging was performed on 10 healthy subjects at 3 Tesla based on single-shot echo-planar imaging using the following parameters: b value, 1000 s/mm2; gradient direction, 15; voxel size, 2 × 2 × 2 mm3; and R factors, 1, 2, 3, 4, and 5. DTT of the right and left pyramidal tracts in the pons was conducted in all subjects. Signal-to-noise ratio (SNR), image distortion, and the number of fibers in the tracts were compared across R factors. Results SNR, image distortion, and fiber number were significantly different according to R factor. Maximal SNR was achieved with an R factor of 2. Image distortion was minimal with an R factor of 5. The number of visible fibers was greatest with an R factor of 3. Conclusion R factor 3 is optimal for DTT of the pontine pyramidal tract. A balanced consideration of SNR and image distortion, which do not have the same dependence on the R factor, is necessary for DTT of the pons.

Background and Purpose Recent advances in intra-arterial techniques and thrombectomy devices lead to high rate of recanalization. However, little is known regarding the effect of the evolvement of endovascular revascularization therapy (ERT) in acute basilar artery occlusion (BAO). We compared the outcome of endovascular mechanical thrombectomy (EMT) versus intra-arterial fibrinolysis (IAF)-based ERT in patients with acute BAO. Methods After retrospectively reviewed a registry of consecutive patients with acute ischemic stroke who underwent ERT from September 2003 to February 2015, 57 patients with acute BAO within 12 hours from stroke onset were enrolled. They were categorized as an IAF group (n=24) and EMT group (n=33) according to the primary technical option. We compared the procedural and clinical outcomes between the groups. Results The time from groin puncture to recanalization was significantly shorter in the EMT group than in the IAF group (48.5 [25.3 to 87.8] vs. 92 [44 to 179] minutes; P=0.02) The rate of complete recanalization was significantly higher in the EMT group than in the IAF group (87.9% vs 41.7%; P

The duplicated origin of vertebral artery (VA) is a very rare condition. It could be easily misdiagnosed as an arterial dissection on selective catheter angiography, especially in a patient with acute cerebellar infarction of unknown etiology. We report a patient with an acute cerebellar infarction and duplicated origin of the left VA, which was found during the selective catheter angiography.

Background: Superficial siderosis (SS) is a rare condition in which hemosiderin, an iron storage complex, is deposited in neural tissues because of recurrent subarachnoid bleeding. Hemosiderin deposition in the vestibulocochlear nerve (CN VIII), brain, spinal cord and peripheral nerve can cause sensorineural hearing loss (SNHL) and postural imbalance, but much remains unknown about the vestibular manifestations of SS.Objectives: To report the clinical course, cochleovestibular status, and patterns of vestibulopathy during follow-up of a relatively large case series, and to discuss the possible pathophysiological mechanism of vestibular deterioration.Methods: Six patients diagnosed with SS by magnetic resonance imaging (MRI) were enrolled. Their medical records and radiological findings were retrospectively reviewed, particularly in terms of progression of the vestibulocochlear manifestations and the radiological characteristics.Results: All six patients had SNHL. Five of them exhibited progressive hearing loss over years, which was asymmetric in four. On their most recent evaluations, patients showed cerebellar ataxia with combined central and peripheral vestibulopathy on both sides (n = 4), a bilateral peripheral vestibulopathy (n = 1) or isolated central vestibulopathy (n = 1). Notably, the former four patients showed an evolution of isolated central vestibulopathy into combined central and peripheral vestibulopathy. Hypo-intense lesions on T2 weighted MRIs were evident around the cerebellum in all patients, but such lesions were observed around the brainstem in five and the CN VIII in four. The cochlea-vestibular dysfunction generally progressed asymmetrically, but no left-right asymmetry was evident on MRI.Conclusions: SS typically presents as bilaterally asymmetric, progressive cochleovestibular dysfunction with cerebellar ataxia. The pattern of vestibular dysfunction is usually combined central and peripheral vestibulopathy on both sides. Thus, precise identification of audiovestibular dysfunction and central signs is essential in SS, and patients with SS should undergo regular, comprehensive neurotological evaluation to optimize their treatments and prognosis.

Background: The aim of this study was to evaluate the value of T1/T2-weighted imaging (T1/T2WI) registration to reduce the postbiopsy hemorrhage effect for prostate cancer localization on prostate magnetic resonance imaging (MRI). Methods: Twenty-one men with pathology-proven prostate cancer who underwent preoperative MRI in a single institution were selected. The zonal anatomy was divided into 16 sections. T2WI, T1/T2-weighted registered imaging (T1/T2RI), T2WI combined with diffusion-weighted imaging (T2WI+DWI), and T1/T2RI combined with DWI (T1/T2RI+DWI) were scored for the likelihood of cancer by two radiology faculty members and two trainees, and were compared with histology results. Areas under the receiver operating characteristics curve (AUCs) were used to assess diagnostic accuracy. Results: For the trainees (Reader 3 and Reader 4), the AUC values were significantly higher (P

Background and Purpose Quantitative magnetic resonance angiography (Q-MRA) enables direct measurement of volume flow rate (VFR) of intracranial arteries. We aimed to evaluate the collateral flows in internal carotid artery (ICA) occlusion with primary collateral pathway via circle of Willis using Q-MRA, and to compare them between patients who recently developed ipsilateral symptomatic ischemia and those who did not. Methods Between 2012 and 2014, 505 patients underwent Q-MRA in our institution. Among these, 33 patients who had unilateral ICA occlusion with primary collateral pathway were identified, and grouped into asymptomatic patients, stable patients with chronic infarction, and symptomatic patients with acute/subacute infarction. Mean VFR (mVFR) in intracranial arteries was measured and compared between the patients’ groups. Kruskal-Wallis test was used for statistical analysis. Results Six patients were asymptomatic, fifteen with chronic infarction were stable, and twelve with acute/subacute infarction were symptomatic. The mVFR of ipsilateral middle cerebral artery in symptomatic patients was significantly lower than those in stable or asymptomatic patients (73.7±45.6 mL/min vs. 119.9±36.1 mL/min vs. 121.8±42.0 mL/min; P = 0.04). Total sum of the mVFR of ipsilateral anterior, middle, and posterior cerebral arteries was significantly lower in symptomatic patients than those in other groups (229.3 ± 51.3 mL/min vs. 282.0±68.6 mL/min vs. 314.0±44.4 mL/min; P = 0.02). Conclusions Q-MRA could be helpful to demonstrate the difference in the degree of primary collateral flow in ICA occlusion between the patients with recent symptomatic ischemia and those without.

To assess the effect of computer-aided detection (CAD) of brain metastasis (BM) on radiologists' diagnostic performance in interpreting three-dimensional brain magnetic resonance (MR) imaging using follow-up imaging and consensus as the reference standard.The institutional review board approved this retrospective study. The study cohort consisted of 110 consecutive patients with BM and 30 patients without BM. The training data set included MR images of 80 patients with 450 BM nodules. The test set included MR images of 30 patients with 134 BM nodules and 30 patients without BM. We developed a CAD system for BM detection using template-matching and K-means clustering algorithms for candidate detection and an artificial neural network for false-positive reduction. Four reviewers (two neuroradiologists and two radiology residents) interpreted the test set images before and after the use of CAD in a sequential manner. The sensitivity, false positive (FP) per case, and reading time were analyzed. A jackknife free-response receiver operating characteristic (JAFROC) method was used to determine the improvement in the diagnostic accuracy.The sensitivity of CAD was 87.3% with an FP per case of 302.4. CAD significantly improved the diagnostic performance of the four reviewers with a figure-of-merit (FOM) of 0.874 (without CAD) vs. 0.898 (with CAD) according to JAFROC analysis (p < 0.01). Statistically significant improvement was noted only for less-experienced reviewers (FOM without vs. with CAD, 0.834 vs. 0.877, p < 0.01). The additional time required to review the CAD results was approximately 72 sec (40% of the total review time).CAD as a second reader helps radiologists improve their diagnostic performance in the detection of BM on MR imaging, particularly for less-experienced reviewers.

Obesity-induced chronic inflammation is known to increase the risk of ulcerative colitis, Crohn's disease, and colorectal cancer. Accumulating evidence suggests that leptin and insulin are key molecules linking obesity with diseases of the lower intestine. Here, we identified serum phenotype-associated genes in the colon of diet-induced obese mice as early biomarkers of obesity-associated colonic diseases. C57BL/6J mice were fed with either normal diet (ND, 15% of fat calories) or high-fat diet (HFD, 45% of fat calories) for 8 weeks. Serum concentrations of insulin, insulin-like growth factor-1 (IGF-1), leptin, and adiponectin were measured as obesity-related phenotypic markers. Genome-wide gene expression profiles of colon tissue were determined, followed by statistical analyses to detect differentially expressed and serum phenotype-associated genes. HFD-fed mice showed higher serum concentrations of leptin (P < 0.001) and insulin (P < 0.01) than those in the ND group, whereas serum IGF-1 and adiponectin concentrations did not differ between the two dietary groups. Among differentially expressed genes affected by HFD, 135, 128, 110, and 341 genes were associated with serum levels of leptin, insulin, IGF-1, and adiponectin, respectively. We identified 17 leptin-associated genes and 4 insulin-associated genes that inversely responded to HFD and ND. Among these, leptin-associated Peli3 (Pellino E3 ubiquitin protein ligase family member 3), Creb1 (cAMP responsive element binding protein 1), and Enpp2 (ectonucleotide pyrophosphatase/phosphodiesterase 2, autotaxin) and insulin-associated Centg1 (AGAP2, ArfGAP with GTPase domain) are reported to play a role either in obesity or colonic diseases. mRNA expression of these genes was validated by RT-qPCR. Our data suggest Peli3, Creb1, Enpp2, and Centg1 as potential early biomarker candidates for obesity-induced pathophysiological changes in the colon. Future studies verifying the function of these candidates are needed for the prevention, early detection, and treatment of colon diseases.

Magnesium is known to lower the risk of cardiovascular disease. However, studies on its relationship with hypertension, a single and common cause of various chronic diseases, are limited and their findings are not consistent. The purpose of the present study is to identify the relationship between magnesium intake and high blood pressure (HBP) risk in Koreans.This research is a cross-sectional study based on the 2007~2009 Korean National Health and Nutritional Examination Survey data. This study investigated 11,685 adults aged over 20 to examine their general characteristics, anthropometry and blood pressure. Daily magnesium intake was analyzed using the 24-hour dietary recall method. To calculate the odds ratio (OR) of HBP risk (130/85 mmHg or over) according to the quartile of magnesium intake (mg/1000 kcal) together with its 95% confidence interval (CI), multivariable logistic regression analysis was performed.No significant association between dietary magnesium intake and the risk of HBP was found. In obese women, particularly, after adjusting relevant factors, the adjusted odds ratio of HBP prevalence in the highest magnesium intake quartile was 0.40 compared with the lowest magnesium intake quartile (95% CI = 0.25~0.63, P for trend = 0.0014). Women, especially obese women, were found to have a negative relationship of magnesium intake with HBP.The present results indicate that sufficient magnesium intake could be useful in decreasing the high blood pressure risk of obese women.