Carotid Magnetization-Prepared Rapid Acquisition With Gradient-Echo Signal Is Associated With Acute Territorial Cerebral Ischemic Events Detected by Diffusion-Weighted MRI

Abstract

Background-Carotid intraplaque hemorrhage has been associated with symptomatic stroke and can be accurately detected with magnetization-prepared rapid acquisition with gradient-echo (MPRAGE). Currently, there are no studies analyzing carotid MPRAGE signal and territorial ischemic events defined by diffusion restriction in the acute setting. Our aim was to determine the association of carotid MPRAGE signal with acute territorial ischemic events using carotid MPRAGE and brain diffusion tensor imaging. Methods and Results-After the addition of the MPRAGE sequence to the neck MR angiographic protocol, 159 patients with suspected acute stroke were evaluated with both brain diffusion tensor imaging and carotid MPRAGE sequences over 2 years, providing 318 carotid artery and paired brain images for analysis. Forty-eight arteries were excluded due to extracarotid sources of brain ischemia and 4 were excluded due to carotid occlusion. Two hundred sixty-six arteries were eligible for data analysis. Carotid MPRAGE-positive signal was associated with an acute cerebral territorial ischemic event with a relative risk of 6.4 (PϽ0.001). The relative risk of a diffusion tensor imaging-positive territorial ischemic event with carotid MPRAGE-positive signal was increased in mild, moderate, and severe stenosis categories (10.3, PϽ0.001; 2.9, Pϭ0.01; and 2.2, Pϭ0.01, respectively). Conclusions-In the workup of acute stroke, carotid MPRAGE-positive signal was associated with an increased risk of territorial cerebral ischemic events as detected objectively by brain diffusion tensor imaging. The relative risk of stroke was increased in all carotid stenosis categories but was most elevated in the mild stenosis category. (Circ Cardiovasc Imaging. 2012;5:376-382.)

Intraluminal Thrombus, Intraplaque Hemorrhage, Plaque Thickness, and Current Smoking Optimally Predict Carotid Stroke

“…12 DTI trace images have been shown to be superior to conventional diffusion-weighted sequences in detecting recent infarcts. 19 Briefly, DTI parameters were 2D, 128×128 matrix, 3 mm slice thickness, B value=2000, 22 directions.…”

“…[12][13][14] Still, it is unclear whether IPH is only a surrogate for other markers of unstable plaque, including plaque thickness, ulceration, or intraluminal thrombus. Recent research suggests that CTA-detected ulceration may be used as a surrogate for IPH.…”

Carotid Intraplaque Hemorrhage Imaging: Diagnostic Value of High Signal Intensity Time-of-Flight MR Angiography Compared with Magnetization-Prepared Rapid Acquisition with Gradient-Echo Sequencing

“…Among the three tested T1-weighted MR sequences, the MPRAGE sequence yielded the best agreement with histologic findings for detecting and quantifying IPH, when compared with fast spine echo and TOF sequencing. Therefore, the MPRAGE sequence was included in the routine MR protocol for the early detection of IPH, although this takes approximately three to four minutes (17)(18)(19).…”

Vitamin D and Vulnerable Carotid Plaque

“…DWI-positive carotid territory infarcts were detected using DTI trace images, which are superior to conventional DWI in detecting recent infarcts. 34,35 The DTI parameters were 2D, 128 ϫ 128 matrix, 3-mm section thickness, bϭ2000, 20 directions. Brain DWI was interpreted by a Certificate of Added qualification-certified neuroradiologist.…”