Evaluation of white matter microstructure in patients with Parkinson’s disease using microscopic fractional anisotropy Abstract Purpose Micro fractional anisotropy (μFA) is more accurate than conventional fractional anisotropy (FA) for assessing microscopic tissue properties and can overcome limitations related to crossing white matter fibres. We compared μFA and FA for evaluating white matter changes in patients with Parkinson’s disease (PD). Methods We compared FA and μFA measures between 25 patients with PD and 25 age- and gender-matched healthy controls using tract-based spatial statistics (TBSS) analysis. We also examined potential correlations between changes, revealed by conventional FA or μFA, and disease duration or Unified Parkinson’s Disease Rating Scale (UPDRS)-III scores. Results Compared with healthy controls, patients with PD had significantly reduced μFA values, mainly in the anterior corona radiata (ACR). In the PD group, μFA values (primarily those from the ACR) were significantly negatively correlated with UPDRS-III motor scores. No significant changes or correlations with disease duration or UPDRS-III scores with tissue properties were detected using conventional FA. Conclusion μFA can evaluate microstructural changes that occur during white matter degeneration in patients with PD and may overcome a key limitation of FA.

Visual pathways evaluation in Kearns Sayre syndrome: a diffusion tensor imaging study Abstract Purpose Kearns Sayre syndrome (KSS) is a mitochondrial disorder characterized by development of visual impairment. Electroretinogram (ERG) and visual evoked potentials are not able to provide topographical information of optic damage. The purpose of this study was to explore retrochiasmatic optic pathway alteration in KSS with diffusion tractographic analysis and to compare it with different tracts. Methods DTI from 8 KSS subjects (14.7 years) and 10 healthy controls (HC) were acquired on a 3T scanner. Optic radiations (OR), optic tracts (OT), inferior frontooccipital fasciculus (IFOF) and corticospinal tract (CST) were reconstructed with probabilistic tractography. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), radial (RD), and axial diffusivity (AD) were calculated, evaluating group differences. T test on diffusion parameters identified significantly different track portions among cohorts. Results All patients had optic pathway alterations at electrophysiological examination. Significant lower FA were found in OT, IFOF, and CST of KSS group. RD was significantly higher in bilateral OR, IFOF, CST, and right OT, while ADC was higher in bilateral OR and CST. RD values were higher in the proximal and distal portion of OR bilaterally and in the distal portion of right OT, while widespread differences were found in IFOF and CST. No significant differences were found for AD. FA profiles analysis demonstrated significant differences between groups in several regions of OT, IFOF, and CST, while ADC assessment revealed spread differences in OR and CST. Conclusions DTI evaluation of retrochiasmatic tracks may represent a useful tool to topographically investigate retrochiasmatic visual impairment in KSS.

Intracranial hemorrhage risk factors after thrombectomy in anterior circulation ischemic stroke

European Society of Neuroradiology (ESNR)

Identifying patients with neuronal intranuclear inclusion disease in Singapore using characteristic diffusion-weighted MR images Abstract Purpose Adult-onset neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder described mainly in the Japanese population, with characteristic DWI abnormalities at the junction between gray and white matter. We identify possible cases of NIID in the picture archive and communication system (PACS) of a tertiary neurological referral hospital in Singapore and describe their radiological features. Methods The neuroradiology imaging database was reviewed using keyword search of radiological reports to identify patients who had “subcortical U fibre” abnormalities on DWI. MRI were retrospectively reviewed, and those fulfilling inclusion criteria were invited for skin biopsy to detect nuclear inclusions by light and electron microscopy. Results Twelve Chinese patients (nine female; median age 70.5 years) were enrolled. Seven patients were being assessed for dementia and five for other neurological indications. In all patients, DWI showed distinctive subcortical high signal with increased average apparent diffusion coefficient (ADC), involving frontal, parietal, and temporal more than occipital lobes; the corpus callosum and external capsule were affected in some patients. On T2-weighted images, cerebral and cerebellar atrophy and white matter hyperintensity of Fazekas grade 2 and above were seen in all patients. Three patients underwent skin biopsy; all were positive for intranuclear hyaline inclusion bodies on either p62 staining or electron microscopy, which are pathognomonic for NIID. Conclusion Previously undiagnosed patients with NIID can be identified by searching for abnormalities at the junction between gray and white matter on DWI in PACS and subsequently confirmed by skin biopsy. Radiologists should recognize the distinctive neuroimaging pattern of this dementing disease.

Plenty of calcification: imaging characterization of polymorphous low-grade neuroepithelial tumor of the young Abstract Purpose Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described epileptogenic neoplasm. As the name implies, PLNTYs are indolent tumors most often encountered in the pediatric or young adult population. The imaging features of PLNTY are not well characterized in the existing literature. Methods We performed a retrospective review, identifying nine patients with pathologically proven PLNTY and available preoperative imaging in order to identify common features which may facilitate confident imaging diagnosis of this entity. Results Patients were ages 5 to 34 years (median 16 years), and seven (78%) were female. Most tumors had a highly characteristic appearance, with temporal lobe location (6/9; 67%), calcification (8/9; 89%), cortical/subcortical origin (8/9; 89%), cystic components (8/9; 89%), and relatively infrequent contrast enhancement (3/9; 33%). Conclusion PLNTYs demonstrate characteristic calcification, subcortical location, and frequent temporal lobe localization, features that may allow radiologists to prospectively suggest the diagnosis in the proper clinical setting.

Dissociative changes in gray matter volume following electroconvulsive therapy in major depressive disorder: a longitudinal structural magnetic resonance imaging study Abstract Purpose Electroconvulsive therapy (ECT), has become a widely applied potent treatment in clinical practice for major depressive disorder (MDD) over decades. However, due to its nonspecific and spatially unfocused nature, the underlying mechanisms of ECT remain unclear. Methods In this longitudinal study, 11 patients with MDD underwent magnetic resonance imaging (MRI) before and after ECT at three different time points. A longitudinal voxel-based morphology approach was performed to characterize dynamic changes in brain gray matter volume (GMV). Twelve age- and sex-matched healthy controls were recruited to identify structural brain changes of patients with MDD before and after ECT. Results The brain GMV was globally found to increase shortly after a series of ECT, and then decrease 1 month after ECT treatment exposure. This fluctuating tendency was localized to the bilateral inferior parietal lobes, bilateral insula, and right superior temporal cortex. After the global GMV was corrected, there were only significant global effect increases in GMV in the left anterior hippocampus and right caudate, which were both significantly correlated with the improvement of depression symptoms. However, 1 month after ECT treatments, there was still significantly reduced GMV following patients with MDD compared to healthy controls in the left putamen, right anterior cingulate, and left inferior temporal cortex, which was observed before ECT. Conclusions These findings indicate that ECT in patients with MDD is closely associated with dissociative structural changes. The locally enhanced GMV in limbic areas may reflect that the ECT-related brain compensatory mechanisms contribute to brain structure recovery in MDD.

Radiomics in peritumoral non-enhancing regions: fractional anisotropy and cerebral blood volume improve prediction of local progression and overall survival in patients with glioblastoma Abstract Purpose The peritumoral non-enhancing region (NER) is frequently not removed during the surgical resection of glioblastoma, with most recurrences occurring within the original treatment field. This study determined whether radiomics analysis of the NER can predict local recurrence and overall survival in patients with glioblastoma. Methods Preoperative magnetic resonance imaging (MRI) scans from 83 consecutive patients with glioblastoma were retrospectively reviewed and grouped into training (n = 59) and test sets (n = 24). A total of 6472 radiomic features were extracted from contrast-enhanced T1-weighted and fluid-attenuated inversion recovery images and from fractional anisotropy (FA) and normalized cerebral blood volume (CBV) maps. A diagnostic model to predict 6-month progression was tested using the area under the receiver operating characteristics curve (AUC) and compared with the single parameters of FA and CBV. A survival model was tested using Harrell’s C-index and compared with clinical models that included age, sex, Karnofsky performance score, and extent of surgical resection. Results Four FA features and six CBV features were selected for the diagnostic model; no features were extracted from conventional MRI. Combined FA and CBV radiomics showed better predictive value for local progression (AUC, 0.79; 95% CI, 0.67–0.90) than single imaging radiomics (AUC, 0.70–0.76) or single imaging parameters (AUC, 0.51–0.54). The combined model (C-index, 0.87) improved prognostication when added to clinical models (C-index, 0.72). Conclusion Radiomics features using FA and CBV in the NER have the potential to improve prediction of local progression and overall survival in patients with glioblastoma.

Diagnostic accuracy of diffusion tensor imaging in differentiating malignant from benign compressed vertebrae Abstract Purpose To study diagnostic accuracy of diffusion tensor imaging (DTI) in differentiating malignant from benign compressed vertebrae. Methods This study was done on 43 patients with compressed vertebrae on conventional magnetic resonance study that underwent DTI. The mean diffusivity (MD) and fractional anisotropy (FA) of malignant (n = 24) and benign (n = 19) compressed vertebrae were calculated by two readers. Results There was a significantly lower (P = 0.001) MD of both readers between malignant (0.74 ± 0.2 and 0.78 ± 0.2 × 10−3 mm2/s) and benign (1.67 + 0.3 and 1.63 ± 0.3 × 10−3 mm2/s) compressed vertebrae. The FA of malignant compressed vertebrae of both readers (0.55 ± 0.2 and 0.52 ± 0.1) was significantly higher (P = 0.001) than that of benign (0.26 ± 0.1 and 0.28 ± 0.1) compressed vertebrae. There was excellent inter-reader agreement between both readers using MD (K = 0.91) and FA (K = 0.86). The thresholds of MD and FA used for differentiating malignant from benign compressed vertebrae of both readers were 1.15 and 1.16 × 10−3 mm2/s and 0.37 and 0.34 with area under the curve (AUC) of 0.98, 0.96, 0.93, and 0.92 and diagnostic accuracy of 95.3%, 88.4%, 90.1%, and 86.0% respectively. Combined MD and FA revealed AUC of 0.99 and 0.97 and diagnostic accuracy of 95.3% and 93.0% by both readers respectively. Conclusion DTI is a non-invasive technique providing accurate imaging parameters that can be used for differentiating malignant from benign compressed vertebrae.

Brain tissue and myelin volumetric analysis in multiple sclerosis at 3T MRI with various in-plane resolutions using synthetic MRI Abstract Purpose Synthetic MRI (SyMRI) enables automatic brain tissue and myelin volumetry based on the quantification of R1 and R2 relaxation rates and proton density. This study aimed to determine the validity of SyMRI brain tissue and myelin volumetry using various in-plane resolutions at 3T in patients with multiple sclerosis (MS). Methods We scanned 19 MS patients and 10 healthy age- and gender-matched controls using a 3T MR scanner with in-plane resolutions of 0.8, 1.8, and 3.6 mm. The acquisition times were 5 min 8 s, 2 min 52 s, and 2 min 1 s, respectively. White matter (WM), gray matter (GM), cerebrospinal fluid (CSF), and myelin and non-WM/GM/CSF (NoN) volumes; brain parenchymal volume (BPV); and intracranial volume (ICV) were compared between different in-plane resolutions. These parameters were also compared between both groups, after ICV normalization. Results No significant differences in measured volumes were noted between the 0.8 and 1.8 mm in-plane resolutions, except in NoN and CSF for healthy controls and NoN for MS patients. Meanwhile, significant volumetric differences were noted in most brain tissues when compared between the 3.6 and 0.8 or 1.8 mm resolution for both healthy controls and MS patients. The normalized WM volume, myelin volume, and BPV showed significant differences between controls and MS patients at in-plane resolutions of 0.8 and 1.8 mm. Conclusions SyMRI brain tissue and myelin volumetry with in-plane resolution as low as 1.8 mm can be useful in the evaluation of MS with a short acquisition time of < 3 min.