Dynamic Susceptibility Contrast (DSC) Perfusion MR in the Prediction of Long-Term Survival of Glioblastomas (GBM): Correlation with MGMT Promoter Methylation and 1p/19q Deletions

Purpose: To investigate the surgical, perfusion, and molecular characteristics of glioblastomas which influence long-term survival after treatment, and to explore the association between MR perfusion parameters and the presence of MGMT methylation and 1p/19q deletions. Materials and Methods: This retrospective study was approved by our institutional review board. A total 43 patients were included, all with pathologic diagnosis of glioblastoma with known MGMT methylation and 1p/19q deletion statuses. We divided these patients into longterm (≥ 60 months, n = 7) and short-term (< 60 months, n = 36) survivors, then compared surgical extent, molecular status, and rCBV parameters between the two groups using Fisher’s exact test or Mann-Whitney test. The rCBV parameters were analyzed according to the presence of MGMT methylation and 1p/19q deletions. We investigated the relationship between the mean rCBV and overall survival using linear correlation. Multivariable linear regression was performed in order to find the variables related to overall survival. Results: Long-term survivors (100% [7 of 7]) demonstrated a greater percentage of gross total or near total resection than short-term survivors (54.5% [18 of 33]). A higher prevalence of 1p/19q deletions was also noted among the long-term survivors (42.9% [3 of 7]) than the short-term survivors (0.0% [0 of 36]). The rCBV parameters did not differ between the longterm and short-term survivors. The rCBV values were marginally lower in patients with MGMT methylation and 1p/19q deletions. Despite no correlation found between overall survival and rCBV in the whole group, the short-term survivor group showed negative correlation (R2 = 0.181, P = 0.025). Multivariable linear regression revealed that surgical extent and 1p/19q deletions, but not rCBV values, were associated with prolonged overall survival. Conclusion: While preoperative rCBV and 1p/19q deletion status are related to each other, only surgical extent and the presence of 1p/19q deletion in GBM patients may predict longterm survival

Atypical Unilateral Posterior Reversible Encephalopathy Syndrome Mimicking a Middle Cerebral Artery Infarction

Posterior reversible encephalopathy syndrome (PRES) is usually a reversible clinical and radiological entity associated with typical features on brain MR or CT imaging. However, the not-so-uncommon atypical radiological presentations of the condition are also present and they may go unrecognised as they are confused with other conditions. Here, we report a very rare case of atypical, unilateral PRES in a 49-year-old uremic, post-transplant female patient who presented with seizures. Initial MRI showed high-grade occlusion of the left middle cerebral artery (MCA) and lesions suggestive of subacute infarction in the ipsilateral frontotemporoparietal lobe. Patient symptoms had resolved a day after the onset without any specific treatment but early follow-up CT findings suggested hemorrhagic transformation. Follow-up MRI performed 2 years later showed complete disappearence of the lesions and persisting MCA occlusion

새로운 KCNQ4 돌연 변이의 발견 및 난청 유형 분석

학위논문 (박사)-- 서울대학교 대학원 의과대학 의학과, 2017. 8. 오승하.KCNQ4 mutations lead to autosomal dominant non-syndromic, and typically progressive and high-frequency, hearing loss (HL). In this report, I identified two novel KCNQ4 mutations, namely p.R331Q and p.811_816del, in two different families. One mutation in the C-terminal region was associated with low- to mid-frequency HL and the other mutation, located in the P-loop, was associated with high frequency HL. Although I did not observe a difference in the subcellular localization of the KCNQ4 mutants p.R331Q and c.811_816del, c.811_816del protein expression was significantly decreased compared with that of wild-type KCNQ4 (KCNQ4WT) and the p.R331Q mutant. The potassium currents were significantly decreased in both the p.R331Q and c.811_816del mutants compared with KCNQ4WT, indicative of the pathogenic potential of the two variants. Based on electrophysiological data, p.R331Q and c.811_816del KCNQ4 channels showed loss of function and a dominant-negative effect when combined with functional KCNQ4WT channels. The heteromeric mutant channels assembled with WT were activated by a KCNQ4 activator (retigabine), and the degree of rescue by retigabine was stronger in the p.R331Q heteromer than in the c.811_816del heteromer. This study reports a C-terminal tail variant among KCNQ4 mutants for the first time, and broadens the audiologic phenotypic spectrum from high frequency sensorineural HL to include low- to mid-frequency sensorineural HL.Introduction 1 Materials and Methods 2 Results 9 Discussion 16 References 20 Figures 24 Abstract (Korean) 33Docto

Direct Rating Estimation of Enlarged Perivascular Spaces (EPVS) in Brain MRI Using Deep Neural Network

In this article, we propose a deep-learning-based estimation model for rating enlarged perivascular spaces (EPVS) in the brain’s basal ganglia region using T2-weighted magnetic resonance imaging (MRI) images. The proposed method estimates the EPVS rating directly from the T2-weighted MRI without using either the detection or the segmentation of EVPS. The model uses the cropped basal ganglia region on the T2-weighted MRI. We formulated the rating of EPVS as a multi-class classification problem. Model performance was evaluated using 96 subjects’ T2-weighted MRI data that were collected from two hospitals. The results show that the proposed method can automatically rate EPVS—demonstrating great potential to be used as a risk indicator of dementia to aid early diagnosis.ope

Central Nervous System Mycobacterium Infection: Tuberculosis and Beyond

Tuberculosis is a contagious infectious disease caused by Mycobacterium tuberculosis, and is the leading cause of death from a single infectious agent worldwide. Imaging plays an important role in the early diagnosis of central nervous system tuberculosis and may prevent unnecessary morbidity and mortality. This article presents an extensive review of pathogenesis, clinical symptoms, typical and atypical imaging appearances of intracranial and spinal tuberculosis, and advanced imaging of intracranial tuberculosis. Furthermore, we explore central nervous system infection of nontuberculous mycobacteria and leprosy and their imaging findings.ope

Altered Functional Brain Networks in Patients with Traumatic Anosmia: Resting-State Functional MRI Based on Graph Theoretical Analysis

Objective: Traumatic anosmia is a common disorder following head injury; however, little is known regarding its neural basis and influence on the functional networks. Therefore, we aimed to investigate the functional connectivity changes in patients with traumatic anosmia compared to healthy controls using resting-state functional magnetic resonance imaging (rs-fMRI). Materials and methods: Sixteen patients with traumatic anosmia and 12 healthy controls underwent rs-fMRI. Differences in the connectivity of the olfactory and whole brain networks were compared between the two groups. Graph theoretical parameters, such as modularity and global efficiency of the whole brain or olfactory networks, were calculated and compared. Correlation analyses were performed between the parameters and disease severity. Results: Patients with traumatic anosmia showed decreased intra-network connectivity in the olfactory network (false discovery rate [FDR]-corrected p < 0.05) compared with that in healthy controls. Furthermore, the inter-network connectivity was increased in both the olfactory (FDR-corrected p < 0.05) and whole brain networks (degree-based statistic-corrected p < 0.05) in the anosmia group. The whole brain networks showed decreased modularity (p < 0.001) and increased global efficiency (p = 0.019) in patients with traumatic anosmia. The modularity and global efficiency were correlated with disease severity in patients with anosmia (p < 0.001 and p = 0.002, respectively). Conclusion: Traumatic anosmia increased the inter-network connectivity observed with rs-fMRI in the olfactory and global brain functional networks. rs-fMRI parameters may serve as potential biomarkers for traumatic anosmia by revealing a more widespread functional damage than previously expected.ope

Assessment of Meningeal Lymphatics in the Parasagittal Dural Space: A Prospective Feasibility Study Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

Objective: Meningeal lymphatic vessels are predominantly located in the parasagittal dural space (PSD); these vessels drain interstitial fluids out of the brain and contribute to the glymphatic system. We aimed to investigate the ability of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the dynamic changes in the meningeal lymphatic vessels in PSD. Materials and Methods: Eighteen participants (26–71 years; male:female, 10:8), without neurological or psychiatric diseases, were prospectively enrolled and underwent DCE-MRI. Three regions of interests (ROIs) were placed on the PSD, superior sagittal sinus (SSS), and cortical vein. Early and delayed enhancement patterns and six kinetic curve-derived parameters were obtained and compared between the three ROIs. Moreover, the participants were grouped into the young (< 65 years; n = 9) or older (≥ 65 years; n = 9) groups. Enhancement patterns and kinetic curve-derived parameters in the PSD were compared between the two groups. Results: The PSD showed different enhancement patterns than the SSS and cortical veins (P < 0.001 and P < 0.001, respectively) in the early and delayed phases. The PSD showed slow early enhancement and a delayed wash-out pattern. The six kinetic curve-derived parameters of PSD was significantly different than that of the SSS and cortical vein. The PSD washout rate of older participants was significantly lower (median, 0.09; interquartile range [IQR], 0.01–0.15) than that of younger participants (median, 0.32; IQR, 0.07–0.45) (P = 0.040). Conclusion: This study shows that the dynamic changes of meningeal lymphatic vessels in PSD can be assessed with DCE-MRI, and the results are different from those of the venous structures. Our finding that delayed wash-out was more pronounced in the PSD of older participants suggests that aging may disturb the meningeal lymphatic drainage.ope

Clinico-radiological features of brain metastases from thyroid cancer

The brain is an unusual site for distant metastases of thyroid cancer. The radiological features of brain metastases (BMs) have rarely been reported. Hemorrhage is frequently noted in BMs from thyroid cancer. This study aimed to investigate the clinico-radiological features of BMs from thyroid cancer and to determine the risk factors to predict BM hemorrhage.We retrospectively evaluated the MR images of 35 patients with BMs from thyroid cancer at our hospital from 2013 to 2020. The number, size, site, presence of extra-cranial metastasis, presence of perilesional edema, intra-tumoral hemorrhage, enhancement pattern, and presence of diffusion restriction on MRI were described. We further classified the thyroid cancers into hemorrhagic and nonhemorrhagic groups to investigate the factors associated with hemorrhage.54.29% of patients with thyroid BMs (19/35) had neurologic symptoms. 94.29% of patients (33/35) had extra-cranial metastases. The most common histology of primary thyroid cancer was papillary thyroid cancer (71.43%, 25/35), followed by anaplastic thyroid cancer (22.86%, 8/35). Thyroid cancer BMs were located mostly in the supra-tentorium (51.43%, 18/35) or both the supra and infra-tentorium (45.71%, 16/35). 60% of patients (21/35) showed hemorrhage within the BMs. The strongest predictor for BM hemorrhage was tumor size (variable importance: 50).Thyroid cancer BMs exhibit a bleeding tendency. Furthermore, larger BMs are more likely to have an intra-tumoral hemorrhage.ope

High-Resolution Vessel Wall Magnetic Resonance Imaging of Varicella-Zoster Virus Vasculopathy Affecting the Vertebrobasilar Artery

Varicella-zoster virus (VZV) has been known to cause intracranial vasculopathy. Herein, we report the case of a patient with VZV vasculopathy involving the vertebrobasilar system who underwent serial high-resolution vessel wall magnetic resonance imaging (HRVW-MRI). The disease continued to worsen radiographically despite clinical symptom improvement. We suggest that VZV vasculopathy may exhibit clinicoradiological dissociation that requires ongoing medical attention. HRVW-MRI may play a critical role in monitoring the disease activity.ope

Dynamic Contrast-Enhanced MRI and Its Applications in Various Central Nervous System Diseases

Dynamic contrast-enhanced MRI (DCE-MRI) is a noninvasive imaging technique used to evaluate tissue vascularity/permeability features through consecutive imaging acquisitions after gadolinium-based contrast agent administration. Over the past several decades, techniques and protocols for DCE-MRI have evolved, leading to growing applications of DCE-MRI for different neurological disorders. Although most established applications of DCE-MRI are for studying tumors, an increasing number of studies have been evaluating the use of this technique for neurodegenerative and other miscellaneous diseases. The purpose of this article was to provide an overview of DCE-MRI and its clinical applications in various neurological diseases.ope