Rivka van den Boom

Descriptive Analysis of the Boston Criteria Applied to a Dutch-Type Cerebral Amyloid Angiopathy Population

Background and Purpose— Validation of the Boston criteria for the in vivo diagnosis of cerebral amyloid angiopathy (CAA) is challenging, because noninvasive diagnostic tests do not exist. Hereditary cerebral hemorrhage with amyloidosis–Dutch type is an accepted monogenetic model of CAA and diagnosis can be made with certainty based on DNA analysis. The aim of this study was to analyze and refine the existing Boston criteria in patients with hereditary cerebral hemorrhage with amyloidosis–Dutch type. Methods— We performed T2*-weighted MRI in 27 patients with hereditary cerebral hemorrhage with amyloidosis–Dutch type to assess the presence and location of microbleeds, intracranial hemorrhages, and superficial siderosis. Using the Boston criteria, subjects were categorized as having: no hemorrhages, possible CAA, probable CAA, and hemorrhagic lesions not qualifying for CAA. The sensitivity of the Boston criteria was calculated separately using intracranial hemorrhages only and using intracranial hemorrhages and microbleeds. Results— The sensitivity of the Boston criteria for probable CAA increased from 48% to 63% when microbleeds were included. For symptomatic subjects only, the sensitivity was 100%. No hemorrhages were identified in the deep white matter, basal ganglia, thalamus, or brainstem. Superficial siderosis, observed in 6 patients, did not increase the sensitivity of the Boston criteria in our study group. Conclusions— Our data show that using T2*-weighted MRI and including microbleeds increase the sensitivity of the Boston criteria. The exclusion of hemorrhages in the deep white matter, basal ganglia, thalamus, and brainstem does not lower the sensitivity of the Boston criteria.

Lacunar Infarcts Are the Main Correlate With Cognitive Dysfunction in CADASIL

Background and Purpose— Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy is caused by mutations in the NOTCH3 gene and is clinically characterized by recurrent stroke and cognitive decline. Previous studies have shown an association between white matter hyperintensities on brain MRI and cognitive dysfunction in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. In the general population the presence of lacunar infarcts and microbleeds is also associated with cognitive dysfunction. The objective of this study was to determine to what extent lacunar infarcts and microbleeds on MRI contribute to cognitive decline in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. Methods— NOTCH3 mutation analysis was performed in 62 symptomatic and asymptomatic members of 15 cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy families. Neuropsychological tests were performed on the same day as the MRI examination. MRI was semi-quantitatively scored for white matter hyperintensities, infarct lesion load, and microbleeds. Regression analysis was performed to test the association between MRI abnormalities and neuropsychological test results. Results— Forty individuals had a NOTCH3 mutation and 22 did not. Severity of cognitive dysfunction in mutation carriers was independently associated with MRI infarct lesion load (P<0.05). In contrast, WMH lesion load and microbleeds were not associated with cognitive dysfunction after correcting for age. Conclusions— Lacunar infarct lesion load is the most important MRI parameter associated with cognitive dysfunction in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Cerebral Hemodynamics and White Matter Hyperintensities in CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small-vessel disease caused by mutations in the NOTCH3 gene on chromosome 19. On magnetic resonance imaging (MRI), subcortical white matter hyperintensities and lacunar infarcts are visualized. It is unknown whether a decrease in cerebral blood flow or cerebrovascular reactivity is primarily responsible for the development of white matter hyperintensities and lacunar infarcts. The authors used phase-contrast MRI in 40 NOTCH3 mutation carriers (mean age 45 ± 10 years) and 22 nonmutated family members (mean age 39 ± 12 years), to assess baseline total cerebral blood flow (TCBF) and cerebrovascular reactivity after acetazolamide. Mean baseline TCBF was significantly decreased in NOTCH3 mutation carriers. In young subjects, baseline TCBF was significantly lower than in nonmutation carriers (mean difference 124 mL/min). Furthermore, baseline TCBF did not differ significantly between mutation carriers with minimal and mutation carriers with moderate or severe white matter hyperintensities. No significant difference in mean cerebrovascular reactivity was found between mutation carriers and nonmutation carriers. This study suggests that a decrease in baseline TCBF in NOTCH3 mutation carriers precedes the development of white matter hyperintensities.

Evaluation of diagnostic NOTCH3 immunostaining in CADASIL.

CADASIL is caused by mutations in the NOTCH3 gene. Although increasingly recognized as a disease entity, the diagnostic confirmation can be lengthy or inconclusive. Recently, NOTCH3 immunostaining of skin biopsy specimens has been introduced as a new diagnostic test. The aim of this study was to independently assess the diagnostic value of NOTCH3 immunostaining, and determine whether the degree of immunostaining correlates with other disease parameters. We determined NOTCH3 mutation carrier status in 62 symptomatic and asymptomatic individuals from 15 CADASIL families. Skin biopsy specimens of these individuals, as well as of a disease control group, were immunostained with NOTCH3 antibody and blindly analyzed by two independent observers to determine sensitivity and specificity. A semiquantitative NOTCH3 immunostaining score was correlated with clinical, genetic and MRI parameters. The sensitivity was 90.2% and 85.4%, respectively, for the two observers, the specificity 95.2% and 100%; both lower than previously reported. Certain NOTCH3 mutations may underlie false-negative results. False-positive results were found in a non-mutated control, and also in one disease control. There was no difference in immunostaining between symptomatic and asymptomatic NOTCH3 mutated individuals. Furthermore, the NOTCH3 immunostaining score did not correlate with clinical or MRI parameters. NOTCH3 immunostaining is a supportive, but not definitive, CADASIL diagnostic test, and should be interpreted in the context of clinical and radiological data. Confirmation by DNA analysis is requisite for positive results, and when there exists high clinical suspicion, also for negative results.

Cerebrovascular Reactivity Is a Main Determinant of White Matter Hyperintensity Progression in CADASIL

BACKGROUND AND PURPOSE: Basal total cerebral blood flow (TCBF) and cerebrovascular reactivity (CVR) are assumed to play an important role in the pathophysiology of small-vessel disease. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a unique monogenetic model to study the pathophysiology of arterial small-vessel disease. The aim of this study was to investigate the role of TCBF and CVR in the progression of MR imaging abnormalities in CADASIL. MATERIALS AND METHODS: Basal TCBF was measured in 25 NOTCH3 mutation carriers and 13 control subjects at baseline. CVR after administration of acetazolamide was measured in 14 NOTCH3 mutation carriers and 9 control subjects. Increase in white matter hyperintensities (WMHs), lacunar infarcts, and microbleeds on MR imaging was measured 7 years later. RESULTS: Lower CVR at baseline was associated with larger increase of WMHs (P = .001) but not with a larger increase of lacunar infarcts or microbleeds. TCBF at baseline was not associated with an increase of MR imaging abnormalities. CONCLUSIONS: Decreased CVR is a potential predictor of disease progression as indicated by increasing WMHs in CADASIL.

MR assessment of cerebral vascular response: a comparison of two methods.

To compare the results and reproducibility of two MR‐based methods of measuring the cerebrovascular response (CVR).

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy: Progression of MR Abnormalities in Prospective 7-year Follow-up Study

PURPOSE To prospectively investigate the patterns and rates of progression of magnetic resonance (MR) imaging abnormalities in a well-documented cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) cohort 7 years after baseline and to identify the prognostic factors that determine the rates and patterns of this progression. MATERIALS AND METHODS The local ethics committee approved the study, and informed consent was obtained from all participants. From 12 unrelated families, 25 patients who were NOTCH3 mutation carriers and 13 who were non-mutation carriers were examined clinically and with standardized MR imaging at baseline and after 7 years. The progression of white matter hyperintensities (WMHs), lacunar infarcts, microbleeding, and brain volume loss was measured semiquantitatively. Correlation testing and group comparison testing were performed to identify the risk factors associated with increased progression of CADASIL-related MR abnormalities. RESULTS Compared with the non-mutation carriers, the mutation carriers showed significant increases in numbers of lacunar infarct (P < .01), WMH (P < .01), and microbleed (P < .05) lesions but no increased loss of brain volume. The distributions of new WMHs and new lacunar infarcts at follow-up were similar to the distributions of these abnormalities at baseline. High WMH (P < .05), lacunar infarct (P < .01), and microbleed (P < .01) lesion loads at baseline--but not cardiovascular risk factors--were associated with faster progression of these abnormalities. CONCLUSION Patients with CADASIL who have a high MR abnormality lesion load at baseline are at risk for faster progression of MR abnormalities.