Intraplaque Hemorrhage Volume and Ischemic Stroke Risk

Intraplaque hemorrhage (IPH) in carotid atherosclerotic plaques is the best established biomarker of plaque vulnerability. However, the relationship between IPH volume and ischemic neurologic symptoms remains scarcely studied. This study explored the association between carotid IPH volume and ischemic event severity.

A retrospective analysis was conducted on consecutive patients with suspected carotid atherosclerosis evaluated from December 2015 to January 2021. Patients underwent carotid plaque MRI using T1-weighted imaging with fat suppression for IPH detection. Included patients had documented neurologic symptoms, classified as amaurosis fugax (AF), TIA, and/or stroke. MRI scans were reviewed for presence and volume of IPH, with semiautomated software used for volumetric segmentation. Statistical analyses, including Mann-Whitney U tests and receiver operating characteristic (ROC) curves, were performed to evaluate IPH volume thresholds and their association with symptom severity.

The study included 358 patients, of whom 69 had IPH-positive carotid plaques. A higher incidence of ischemic events was noted on the left side, with 28 strokes, 6 AF, and 12 TIAs observed in left-sided events, and 19 strokes, 1 AF, and 3 TIAs in right-sided events. No substantial differences in IPH volumes were found across symptom categories or event laterality. ROC analysis identified IPH volume thresholds with area under the curve values of 0.579 (0.396, 0.748) for left-sided events and 0.618 (0.333, 0.910) for right-sided events, indicating limited discriminatory power for predicting ischemic event severity.

While carotid IPH volume is detectable across various neurologic symptom categories, our findings indicate that IPH volume alone does not significantly correlate with ischemic event severity. Threshold IPH volumes showed low diagnostic accuracy, suggesting that other plaque characteristics and systemic factors may be more relevant in determining ischemic stroke risk.