Li Dong1, Zhaoqi Zhang1, Wei Yu1, Sheng Wang2, Qiang Shen1, and Chun Yuan3
1Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, People's Republic of China, 2Department of Vascular disease, Beijing Anzhen Hospital, Capital Medical University, Beijing, People's Republic of China, 3Department of Radiology, University of Washington, Seattle, WA, United States
Synopsis
Histological studies have shown
that intraplaque hemorrhage (IPH) size might be important in assessing disease
severity. We hypotheses that the quantitative measurements of IPH by MRI provide
additional value towards classify acute cerebral infarcts (ACI) in the carotid
territory by brain MRI. We found that the subjects with ACI had larger max %
IPH measurements (AUC=84.7%, p=0.015) and IPH closer to the lumen (AUC=85.4%,
p=0.012). Further, using the size and distance measurements simultaneously
improved the AUC to 96.9%. Beyond the presence of IPH, quantitative
measurements of IPH may improve the predictive value of carotid plaque imaging
for future stroke.
Background
Intraplaque hemorrhage (IPH) in the carotid
atherosclerotic lesion has been identified as a key component that
significantly triggers disease progression. From in vivo natural history
studies with carotid MRI, the presence of IPH has been associated with
accelerated expansion of plaque burden and increased luminal narrowing1,2. Histological studies have shown that intraplaque
hemorrhage (IPH) size might be important in assessing disease severity3. Purpose
This study was to investigate whether the quantitative
measurements of IPH (e.g. size and its distance to the lumen) can provide
additional value towards predicting acute cerebral infarcts (ACI) in the
carotid territory.Method
A total of 77 patients with >or=50% carotid
stenosis by duplex ultrasound underwent multi-contrast carotid and brain MRI
scans at 3T. Carotid MRI scans were performed using a high-resolution
multi-contrast protocol, including TOF, T2W, IW, and pre- and post-contrast T1W
imaging. MR imaging of the brain was subsequently performed including T1W, T2W,
and diffusion weighted imaging (DWI). Two radiologists reviewed carotid images
and brain images independently. From carotid MRI, two quantitative measurements
for IPH—max % size (maximum value of IPH area / wall area x 100% over all
slices) and minimum distance to the lumen—were measured using a custom-designed
image analysis tool. From brain MRI, the presence of ACI in the ipsilateral
carotid territory was recorded according to DWI images. Diagnostic accuracy was
assessed using sensitivity and specificity for binary variables and area under
the ROC curve (AUC) for continuous variables. Logistic regression was used to
combine continuous variables into a single predictor.Results
Two subjects were excluded due to poor image quality
and one was excluded due to total occlusion. Of the remaining subjects (n=74),
17 (23%) had IPH and 14 (19%) had ACI. The presence of IPH was significantly
associated with the presence of ACI (OR=7.6, p=0.002). Only the subjects with
IPH (n = 17) were used to assess the quantitative IPH measurements. Of those,
the subjects with ACI had larger max % IPH measurements (AUC=84.7%, p=0.015)
and IPH closer to the lumen (AUC=85.4%, p=0.012). Further, using the size and
distance measurements simultaneously improved the AUC to 96.9%.Discussion
The results demonstrate
that compared with intraplaque hemorrhage presence alone,
quantitative measurements of the size and proximity of intraplaque hemorrhage
to the lumen contribute additional valuable information regarding likelihood of
acute cerebral infarcts in subjects with advanced carotid atherosclerosis. For
the clinical application, beyond the presence of intraplaque hemorrhage,
quantitative measurements of intraplaque hemorrhage may improve the predictive
value of carotid plaque imaging for future stroke.Acknowledgements
No acknowledgement found.References
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