RadioGraphics Update: White Matter Diseases with Radiologic-Pathologic Correlation

Diffusion-Weighted Images and Contrast-Enhanced MRI in the Diagnosis of Different Stages of Multiple Sclerosis of the Central Nervous System

Introduction Multiple sclerosis (MS) is one of the most prevalent disorders of the central nervous system (CNS), and it can be observed in the field of radiological cross-sectional magnetic resonance imaging (MRI). The prevalence of MS in Saudi Arabia has increased as compared to the past few years. MRI is the gold standard non-invasive modality of choice in MS diagnosis according to the National Multiple Sclerosis Society (NMSS), New York City. This study aimed to highlight the significance of using diffusion-weighted images (DWIs) and the use of contrast media in the MS protocol, as well as the importance of identifying the suitable time of imaging after contrast enhancement to detect active lesions. Methods A retrospective cross-sectional study was conducted of 100 MS patients with an age range of 17 to 56 years. The data set included 41 active cases and 59 inactive cases. All patients had an MRI standard protocol of both the brain and spine in addition to DWI sequence and contrast agent (CA) injection, with images taken in early and delayed time. Results Of the patients, 71% were female and 29% were male. Active MS disease was more significant at younger ages than at older ages. Active lesions were significantly enhanced in delayed contrast images and showed high signal intensity in both the DWI and apparent diffusion coefficient (ADC) map, while inactive lesions showed no enhancement after contrast injection and showed an iso-signal intensity in both the DWI and ADC map. Conclusion The use of CA has developed over the years in the diagnosis of MS patients. In this study, the relationship between active lesions, DWI, and delayed contrast enhancement is very strong. In future research, we recommend adding a DWI sequence for the suspected active MS spine lesions in addition to delayed enhancement time in active MS after contrast injection to increase MRI sensitivity toward active MS lesions of the brain and spinal cord as well.

Clinical and epidemiological profiles from a case series of 26 Brazilian CADASIL patients

BACKGROUND

 Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetic cause of ischemic stroke and the most common form of non-atherosclerotic stroke. Despite being the most prevalent vascular hereditary disease, clinical data regarding the Brazilian population are scarce. Considering that the Brazilian population has one of the most heterogeneous genetic constitutions in the world, knowledge about genetic and epidemiological profiles is mandatory. The present study aimed to elucidate the epidemiological and clinical features of CADASIL in Brazil.

METHODS

 We performed a case series study comprising 6 rehabilitation hospitals in Brazil and reported the clinical and epidemiological data from the medical records of patients admitted from 2002 to 2019 with genetic confirmation.

RESULTS

 We enrolled 26 (16 female) patients in whom mutations in exons 4 and 19 were the most common. The mean age at the onset of the disease was of 45 years. Ischemic stroke was the first cardinal symptom in 19 patients. Cognitive impairment, dementia, and psychiatric manifestations were detected in 17, 6, and 16 patients respectively. In total, 8 patients had recurrent migraines, with aura in 6 (75%) of them. White matter hyperintensities in the temporal lobe and the external capsule were found in 20 (91%) and 15 patients (68%) respectively. The median Fazekas score was of 2. Lacunar infarcts, microbleeds, and larger hemorrhages were observed in 18 (82%), 9, and 2 patients respectively.

CONCLUSION

 The present is the most extensive series of Brazilian CADASIL patients published to date, and we have reported the first case of microbleeds in the spinal cord of a CADASIL patient. Most of our clinical and epidemiological data are in accordance with European cohorts, except for microbleeds and hemorrhagic strokes, for which rates fall in between those of European and Asian cohorts.

White Matter Hyperintensities Quantification in Healthy Adults: A Systematic Review and Meta-Analysis

BACKGROUND

Although white matter hyperintensities (WMH) volumetric assessment is now customary in research studies, inconsistent WMH measures among homogenous populations may prevent the clinical usability of this biomarker.

PURPOSE

To determine whether a point estimate and reference standard for WMH volume in the healthy aging population could be determined.

STUDY TYPE

Systematic review and meta-analysis.

POPULATION

In all, 9716 adult subjects from 38 studies reporting WMH volume were retrieved following a systematic search on EMBASE.

FIELD STRENGTH/SEQUENCE

1.0T, 1.5T, or 3.0T/fluid-attenuated inversion recovery (FLAIR) and/or proton density/T₂ -weighted fast spin echo sequences or gradient echo T₁ -weighted sequences.

ASSESSMENT

After a literature search, sample size, demographics, magnetic field strength, MRI sequences, level of automation in WMH assessment, study population, and WMH volume were extracted.

STATISTICAL TESTS

The pooled WMH volume with 95% confidence interval (CI) was calculated using the random-effect model. The I² statistic was calculated as a measure of heterogeneity across studies. Meta-regression analysis of WMH volume on age was performed.

RESULTS

Of the 38 studies analyzed, 17 reported WMH volume as the mean and standard deviation (SD) and were included in the meta-analysis. Mean and SD of age was 66.11 ± 10.92 years (percentage of men 50.45% ± 21.48%). Heterogeneity was very high (I²  = 99%). The pooled WMH volume was 4.70 cm³ (95% CI: 3.88-5.53 cm³ ). At meta-regression analysis, WMH volume was positively associated with subjects' age (β = 0.358 cm³ per year, P < 0.05, R²  = 0.27).

DATA CONCLUSION

The lack of standardization in the definition of WMH together with the high technical variability in assessment may explain a large component of the observed heterogeneity. Currently, volumes of WMH in healthy subjects are not comparable between studies and an estimate and reference interval could not be determined.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 1.