Hemispheric Differences in Leukoaraiosis in Patients with Carotid Artery Stenosis: A Systematic Review.

PURPOSE: Despite the prevalence of leukoaraiosis in neuroimaging and its link to dementia, stroke, and death, the exact pathogenesis is still unclear. While some have postulated a link between carotid artery disease and leukoaraiosis, the exact relationship between the two common clinical findings is unknown. To determine the link between carotid disease and leukoaraiosis, we performed a systematic review of interhemispheric differences in white matter disease in patients with carotid artery disease. METHODS: We performed a comprehensive literature search in multiple electronic databases evaluating the association of carotid artery and white matter disease using both subjective and volumetric assessment of white matter burden. The included studies examined patients with at least 30 % carotid artery stenosis for white matter burden both ipsilateral and contralateral to the site of carotid artery disease. RESULTS: Of the 2920 manuscripts screened, five were included in the systematic review. One study used a volumetric analysis of the white matter burden and the others used various subjective methods. Four studies found no statistically significant relationship between carotid artery disease and ipsilateral white matter burden and one study found a significantly higher amount of white matter disease ipsilateral to carotid artery stenosis. CONCLUSIONS: The mixed results in degree of hemispheric leukoaraiosis in patients with carotid artery disease indicate that no definite relationship can be established based on the existing literature. Given the complex nature of carotid artery disease, including increased risk with certain plaque components, the exact relationship requires further investigation with more rigorous research design.

Automated calcium burden measurement in internal carotid artery plaque with CT: a hierarchical adaptive approach.

AIM: Calcium burden measurement in internal carotid artery (ICA) plaque could play an important role in assessing stroke risk and stenosis quantification in the ICA. We propose an automatic method for labelling calcified plaques in ICA in CT images. METHODS: Our approach builds upon the mean shift paradigm via an adaptive thresholding strategy. The data consists of single CT slices from 75 patients, with variety of plaque sizes and number of calcium regions. The manual measurements were carried out by a neuroradiologist for benchmarking. The calcium burden was measured as the area of the labelled plaque. Various metrics were employed to compare manual and automated measurements including correlation coefficient (CC), dice similarity (DS), Jacard Index (JI), polyline distance metric (PDM) and precision of merit (PoM). RESULTS: We found that our automated method of calcium area characterization performed accurately compared to manual measurements with CC=0.978, and PoM=0.915. The PDM, DS, and JI, also indicate a good performance with a mean DS=0.85 (SD=0.085), a mean JI=0.747 (SD=0.12), and a mean PDM=0.195 (SD=0.177). CONCLUSION: The proposed approach for calcium burden measurement, yields reasonably accurate labelling of calcified plaque when benchmarked against manual measurements. The approach is independent of the number and size of calcium regions, and the prototype design shows encouraging results to be adaptable to clinical practice.

CT angiographic features of symptom-producing plaque in moderate-grade carotid artery stenosis.

BACKGROUND AND PURPOSE: Emerging evidence indicates that plaque imaging can improve stroke risk stratification in patients with carotid artery atherosclerosis. We studied the association between soft and hard (calcified) plaque thickness measurements on CTA and symptomatic disease status (ipsilateral stroke or TIA) in patients with moderate-grade carotid artery stenosis. MATERIALS AND METHODS: We measured soft-plaque and hard-plaque thickness on CTA axial source images in each carotid artery plaque in subjects with NASCET 50%-69% ICA stenosis. We used logistic regression and receiver operating characteristic analyses to assess the strength of the association between thickness measurements and prior stroke or TIA. RESULTS: Twenty of 72 vessels studied (27.7%) had ischemic symptoms ipsilateral to the side of moderate-grade carotid stenosis. Each 1-mm increase in soft plaque resulted in a 3.7 times greater odds of a prior ipsilateral ischemic event (95% CI, 1.9-7.2). Conversely, for each 1-mm increase in hard plaque, the odds of being symptomatic decreased by approximately 80% (OR, 0.22; 95% CI, 0.10%-0.48%). Receiver operating characteristic analysis showed an area under the curve of 0.88 by using soft-plaque thickness measurements to discriminate between asymptomatic and symptomatic plaques. Sensitivity and specificity were optimized by using a maximum soft-plaque thickness of 2.2 mm, which provided a sensitivity of 85% and a specificity of 83%. CONCLUSIONS: Simple CTA plaque-thickness measurements might differentiate symptomatic and asymptomatic moderate-grade carotid artery plaque. With further prospective validation, CTA plaque measures could function as an easily implementable tool for risk stratification in carotid artery disease.