Prediction of Carotid Intraplaque Hemorrhage Using Adventitial Calcification and Plaque Thickness on CTA
L B Eisenmenger1, B W Aldred1, S-E Kim1
1From the Department of Radiology (L.B.E., B.W.A., S.-E.K., G.S.T., D.L.P., J.S.M.), Utah Center for Advanced Imaging Research.
Insights
The CTA rim sign, indicating adventitial calcification with soft plaque, strongly predicts carotid intraplaque hemorrhage. This finding improves stroke risk assessment in patients with carotid atherosclerosis.
Area of Science:
- Vascular imaging and diagnostics
- Cardiovascular research
- Stroke prevention
Background:
- Carotid intraplaque hemorrhage (IPH) is linked to stroke, plaque thickness, stenosis, ulceration, and adventitial inflammation.
- The role of calcification in plaque instability is debated, and adventitial calcification has not been studied.
- Existing data on plaque characteristics and stroke risk require further clarification.
Purpose of the Study:
- To investigate whether adventitial calcification and soft plaque, identified as the "rim sign" on CTA, predict carotid intraplaque hemorrhage.
- To assess the predictive value of the rim sign and soft plaque for IPH.
- To compare the predictive accuracy of the rim sign against established markers like stenosis and ulceration.
Main Methods:
- Retrospective cohort study of 96 patients (188 carotid arteries) with carotid MRA and CTA.
- Intraplaque hemorrhage (IPH) detected via MPRAGE; calcification, adventitial pattern, stenosis, plaque thickness (soft/hard), ulceration, and thrombus recorded on CTA.
- Multivariable Poisson regression and ROC analysis used to determine predictive value for IPH.
Main Results:
- The final model, including the "rim sign" and maximum soft plaque thickness, demonstrated excellent IPH prediction (AUC = 0.94).
- The rim sign alone showed high predictive value (AUC = 0.88), outperforming NASCET stenosis (AUC = 0.77) and ulceration (AUC = 0.63).
- Combining the rim sign with other markers significantly improved IPH prediction compared to individual markers.
Conclusions:
- The "rim sign" on CTA, representing adventitial calcification with internal soft plaque, is a highly accurate predictor of carotid intraplaque hemorrhage.
- This imaging marker offers a valuable tool for assessing stroke risk in patients with carotid atherosclerosis.
- The study highlights the importance of adventitial calcification and soft plaque characteristics in predicting plaque instability and hemorrhage.
Background And Purpose:
Carotid intraplaque hemorrhage is associated with stroke, plaque thickness, stenosis, ulceration, and adventitial inflammation. Conflicting data exist on whether calcification is a marker of plaque instability, and no data exist on adventitial calcification. Our goal was to determine whether adventitial calcification and soft plaque (a rim sign) help predict carotid intraplaque hemorrhage.
Materials And Methods:
This was a retrospective cohort study of 96 patients who underwent carotid MRA and CTA within 1 month, from 2009 to 2016. We excluded occlusions (n = 4) and near occlusions (n = 0), leaving 188 carotid arteries. Intraplaque hemorrhage was detected by using MPRAGE. Calcification, adventitial pattern, stenosis, maximum plaque thickness (total, soft, and hard), ulceration, and intraluminal thrombus on CTA were recorded. Atherosclerosis risk factors and medications were recorded. We used mixed-effects multivariable Poisson regression, accounting for 2 vessels per patient. For the final model, backward elimination was used with a threshold of P < .10. Receiver operating characteristic analysis determined intraplaque hemorrhage by using the area under the curve.
Results:
Our final model included the rim sign (prevalence ratio = 11.9, P < .001) and maximum soft-plaque thickness (prevalence ratio = 1.2, P = .06). This model had excellent intraplaque hemorrhage prediction (area under the curve = 0.94), outperforming the rim sign, maximum soft-plaque thickness, NASCET stenosis, and ulceration (area under the curve = 0.88, 0.86, 0.77, and 0.63, respectively; P < .001). Addition of the rim sign performed better than each marker alone, including maximum soft-plaque thickness (area under the curve = 0.94 versus 0.86, P < .001), NASCET stenosis (area under the curve = 0.90 versus 0.77, P < .001), and ulceration (area under the curve = 0.90 versus 0.63, P < .001).
Conclusions:
The CTA rim sign of adventitial calcification with internal soft plaque is highly predictive of carotid intraplaque hemorrhage.
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