Neuroradiology

Correction to: Diagnostic performance of an unenhanced MRI exam for tumor follow-up of the optic pathway gliomas in children In the article "Diagnostic performance of an unenhanced MRI exam for tumor follow-up of the optic pathway gliomas in children", Table 2 data were not presented correctly, with results placed beneath an incorrect heading. Confidence interval also added. The original article has been corrected.

European Society of Neuroradiology (ESNR)

Spontaneous recanalization and hyperperfusion are relatively common at presentation in pediatric arterial ischemic stroke

Assessment of quantitative methods for enhancement measurement on vessel wall magnetic resonance imaging evaluation of intracranial atherosclerosis Abstract Purpose Quantitative measures of vessel wall magnetic resonance imaging (vwMRI) for the evaluation of intracranial atherosclerotic disease (ICAD) offers standardization not available with previously used qualitative approaches that may be difficult to replicate. Methods vwMRI studies performed to evaluate ICAD that had caused a stroke were analyzed. Two blinded reviewers qualitatively rated culprit lesions for the presence of enhancement on T1 delay alternating with nutation for tailored excitation (DANTE) SPACE images. At least 3 months later, quantitative analysis was performed of the same images, comparing lesion enhancement to reference structures. Cohen's kappa and intraclass correlation coefficients were calculated to assess agreement. Ratios of enhancement of lesions to references were compared to qualitative ratings. Results Studies from 54 patients met inclusion criteria. A mean of 49 (90.7%) lesions were qualitatively rated as enhancing, with good inter-rater agreement (κ = 0.783). Among reference structure candidates, low infundibulum demonstrated the highest inter-rater agreement on pre- and post-contrast imaging. The ratio of percentage increase in plaque signal following contrast to the same measure in low infundibulum demonstrated the highest agreement with qualitative assessment, with highest agreement seen with a ratio of 0.8 set as a threshold (κ = 0.675). Conclusion Quantitative metrics can yield objective data to better standardize techniques and acceptance of vwMRI evaluation of ICAD. The low infundibulum had the highest inter-rater agreement on both pre- and post-contrast images and is best suited as a normally enhancing reference structure. Such quantitative techniques should be implemented in future research of vwMRI for the evaluation of ICAD.

Gray matter reduction related to decreased serum creatinine and increased triglyceride, Hemoglobin A1C, and low-density lipoprotein in subjects with obesity Abstract Purpose Altered brain volume and metabolic variables have been found in subjects with obesity. However, the role of metabolic parameters in gray matter volume (GMV) has been poorly investigated. This study aimed to investigate the relationship between the metabolic parameters and brain volume in subjects with obesity. Methods Thirty-seven subjects with obesity and 39 age and sex matched normal-weight controls were included in this study. Eighteen of the 37 participants who underwent sleeve gastrectomy were included in the longitudinal analysis. Blood samples and high-resolution 3T T1-weighted magnetic resonance images were collected. Metabolic parameters in plasma and GMV were measured. Results Multiple linear regression analysis showed that gray matter reduction in several cognition-related cortices including right angular gyrus, superior occipital cortex, superior parietal cortex, and cerebellum was related to decreased creatinine, as well as increased triglyceride, HbA1c, and low-density lipoprotein in plasma in subjects with obesity. Weight loss after the surgery induced significant recovery of altered metabolic parameters and decreased gray matter volume. Furthermore, changes in the four metabolic parameters before and after the surgery were associated with changes in gray matter volume. Conclusion Our results suggest that the gray matter reduction is related to decreased creatinine as well as increased triglyceride, HbA1c, and low-density lipoprotein in plasma in subjects with obesity.

Diagnostic performance of an unenhanced MRI exam for tumor follow-up of the optic pathway gliomas in children Abstract Purpose Contrast-enhanced MRI (MRI + C) is considered as mandatory for brain tumors follow-up, but gadolinium brain depositions in relation with repeated injections have been reported. The aim of our work was to evaluate the diagnostic performance of an unenhanced MRI examination for the follow-up of optic pathway gliomas (OPG) in children. Methods Seventeen patients (with/without NF1) were selected from 2001 to 2017, with at least 5 MRI + C brain follow-up examinations. Privacy and data protection rights were addressed by the data protection officer (DPO) and the study was in accordance with the local ethical rules. Twenty-five cases of tumor progression and 25 cases of tumor stability mentioned in the conclusion of radiological reports (defined as gold standard) were isolated. Those exams were anonymized and independently reviewed by two radiologists, who analyzed both quantitative (such as tumor volume variation) and qualitative criteria (such as ventricular dilatation) on unenhanced images. Sensitivity, specificity, positive/negative predictive values (PPV, NPV), and inter/intra-observer agreement were calculated. Results The mean age of patients was 5.4 ± 3.4 years and mean follow-up length 6.7 years. The mean number of MRI + C was 13.5 (SD 7.2). The sensitivity of unenhanced MRI for tumor follow-up was 84–88% (95% CI 63.9–97.5). The specificity was 91.3–100% (95% CI 72–100). The PPV was 91.7% for reader 1 and 100% for reader 2. The NVP was 87.5% for reader 1 and 85.2% for reader 2. There was an excellent inter-observer agreement regarding tumor progression: kappa coefficient of 0.87 (p < 0.001). Inter/intra-variability for percentage of tumor volume variation between two exams were good (correlation coefficients of 0.97 and 0.94). Conclusion Tumor volume variation is in most cases sufficient to assess OPG progression. Systematic MRI + C could be questionable.

Brain regional volume estimations with NeuroQuant and FIRST: a study in patients with a clinically isolated syndrome Abstract Purpose Brain volume estimates from magnetic resonance images (MRIs) are of great interest in multiple sclerosis, and several automated tools have been developed for this purpose. The goal of this study was to assess the agreement between two tools, NeuroQuant® (NQ) and FMRIB's Integrated Registration Segmentation Tool (FIRST), for estimating overall and regional brain volume in a cohort of patients with a clinically isolated syndrome (CIS). In addition, white matter lesion volume was estimated with NQ and the Lesion Segmentation Toolbox (LST). Methods One hundred fifteen CIS patients were analysed. Structural images were acquired on a 3.0-T system. The volume agreement between methods (by estimation of the intraclass correlation coefficient) was calculated for the right and left thalamus, caudate, putamen, pallidum, hippocampus, and amygdala, as well as for the total intracranial volume and white matter lesion volume. Results In general, the estimated volumes were larger by NQ than FIRST, except for the pallidum. Agreement was low (ICC < 0.40) for the smaller structures (amygdala and pallidum) and fair to good (ICC > 0.40) for the remaining ones. Agreement was fair for lesion volume (ICC = 0.61), with NQ estimates lower than LST. Conclusions Agreement between NQ and FIRST brain volume estimates depends on the size of the structure of interest, with larger volumes achieving better agreement. In addition, concordance between the two tools does seem to be dependent on the presence of brain lesions.

Motor cortex hypointensity on susceptibility-weighted imaging: a potential imaging marker of iron accumulation in patients with cognitive impairment Abstract Purpose To assess the prevalence and characteristics of motor cortex hypointensity on 3-T susceptibility-weighted imaging (SWI) in patients with cognitive impairment and examine its clinical significance. Methods The institutional review board approved this retrospective study and waived the requirement for informed consent. A total of 127 patients with a clinical diagnosis of probable Alzheimer's disease (AD) (n = 32) or mild cognitive impairment (MCI) (n = 95) and 127 age- and sex-matched control subjects underwent 3-T brain magnetic resonance imaging. SWI was analyzed for both subjective visual scoring and the quantitative estimation of phase shift in the posterior bank of the motor cortex. A multivariate logistic regression analysis was performed to identify clinical and imaging variables associated with motor cortex hypointensity on SWI. Results Motor cortex hypointensity on SWI was observed in 94/127 cognitively impaired patients (74.0%) and 72/127 control subjects (56.7%) (p = 0.004). Age was the only variable that was significantly associated with motor cortex hypointensity in patients with cognitive impairment (odds ratio, 1.15; 95% confidence interval, 1.065–1.242; p < 0.001). The quantitative analysis confirmed a significant increase in phase shifting in the posterior bank of the motor cortex in patients with positive motor cortex hypointensity on SWI (p < 0.001). Conclusion Motor cortex hypointensity on SWI was more frequently found in patients with cognitive impairment than in age-matched controls and was positively associated with age. Thus, it may be a potential imaging marker of iron accumulation in patients with MCI or AD.

Microstructural brain abnormalities correlate with neurocognitive dysfunction in minimal hepatic encephalopathy: a diffusion kurtosis imaging study Abstract Purpose To investigate the diffusion kurtosis imaging (DKI) in early minimal hepatic encephalopathy (MHE) diagnosis and evaluate the correlations between changes in DKI metrics and cognitive performance. Methods We enrolled 116 cirrhosis patients, divided into non-HE (n = 61) and MHE (n = 55), and 46 normal controls (NCs). All patients underwent cognitive testing before magnetic resonance imaging. DKI metrics were calculated through whole-brain voxel-based analysis (VBA) and differences between the groups were assessed. Pearson correlation between the DKI metrics and cognitive performance was analysed. The receiver operating characteristic (ROC) curve was used to analyse the diagnostic efficiency of DKI metrics for MHE. Results MHE patients had significantly altered DKI metrics in a wide range of regions; lower fractional anisotropy (FA) and higher mean diffusivity (MD) are mainly located in the corpus callosum, left temporal white matter (WM), and right medial frontal WM. Furthermore, significantly altered kurtosis metrics included lower mean kurtosis (MK) in the corpus callosum and left thalamus, lower radial kurtosis (RK) in the corpus callosum, and lower axial kurtosis (AK) in the right anterior thalamic radiation. Alterations in axial diffusivity (AD), radial diffusivity (RD), and MD were closely correlated with cognitive scores. The ROC curves indicated AD in the forceps minor had the highest predictive performance for MHE in the cirrhosis patients (area under curve = 0.801, sensitivity = 77.05%, specificity = 74.55%). Conclusions Altered DKI metrics indicate brain microstructure abnormalities in MHE patients, some of which may be used as neuroimaging markers for early MHE diagnosis.

Structural and functional abnormalities of vision-related brain regions in cirrhotic patients: a MRI study Abstract Purpose Previous studies have focused on global cerebral alterations observed in cirrhosis. However, little was known about the specific abnormalities of vision-related brain regions in cirrhotic patients. In this study, we sought to explore neurological alterations of vision-related regions by measuring brain resting-state network connectivity, based on the structural investigation in cirrhotic patients without clinical sign of hepatic encephalopathy (HE). Methods Structural and functional magnetic resonance image (MRI) data were collected from 20 hepatitis B virus (HBV)-related cirrhotic patients without clinical sign of HE and from 20 healthy controls (HC). Voxel-based morphometric (VBM) analysis and brain functional network analysis were performed to detect abnormalities in cerebral structure and function. Results Cirrhotic patients showed regions with the most significant gray matter reduction primarily in vision-related brain regions, including the bilateral lingual gyri, left putamen, right fusiform gyrus, and right calcarine gyrus, and other significant gray matter reductions were distributed in bilateral hippocampus. Based on structural investigation focused on vision-related regions, brain functional network analysis revealed decreased functional connectivity between brain functional networks within vision-related regions (primary visual network (PVN), higher visual network (HVN), visuospatial network (VSN)) in the patient group compared with HC group. Conclusion These results indicate that structural and functional impairment were evident in the vision-related brain regions in cirrhotic patients without clinical sign of hepatic encephalopathy. The physiopathology and clinical relevance of these changes could not be ascertained from the present study, which provided a basis for further evolution of the disease.