Diagnostic accuracy of a clinical carotid plaque MR protocol using a neurovascular coil compared to a surface coil protocol

Abstract

Background Carotid plaque imaging with MRI is becoming more commonplace, but practical challenges exist in performing plaque imaging with surface coils. Purpose To compare the diagnostic performance of a carotid plaque MRI protocol using a standard neurovascular coil (Neurovascular Coil Protocol) to a higher‐resolution carotid plaque MRI using carotid surface coils (Surface Coil Protocol) in characterizing carotid plaque. Study Type Prospective study comparing two MR techniques in plaque characterization. Population Thirty‐eight consecutive carotid artery disease patients. Field Strength/Sequence Patients underwent 3T MRI using 1) a Neurovascular Coil Protocol including the following sequences: 3D‐FSE T₁ pre/postcontrast and precontrast 3D IR‐FSPGR, and 2) a Surface Coil Protocol using standard multicontrast MRI sequences. Assessment Plaque characteristics analyzed by two independent neuroradiologists included intraplaque hemorrhage (IPH), lipid‐rich necrotic‐core (LRNC), and thin/ruptured fibrous cap (TRFC). Statistical Tests Diagnostic performance of the Neurovascular Coil Protocol was compared to the Surface Coil Protocol reference standard using receiver‐operating curves. Results For IPH, sensitivity, specificity, and area under the curve (AUC) of the Neurovascular Coil Protocol were 91.1% (95% confidence interval [CI] = 78.8–97.5%), 87.0% (95% CI = 66.4–97.2%), and 0.92, respectively. For LRNC without IPH sensitivity, specificity, and AUC were 73.3% (95% CI = 44.9–92.2%), 85.7% (95% CI = 67.3–96.0%), and 0.84, respectively. For TRFC, sensitivity, specificity, and AUC were 35.3% (95% CI = 14.2–61.7%), 97.6% (95% CI = 87.4–99.9%), and 0.66 respectively. Interobserver agreement for IPH, LRNC, and TRFC using the Neurovascular Coil Protocol were k = 0.87 (95% CI = 0.75–0.99), k = 0.54 (95% CI = 0.29–0.80), and k = 0.41 (95% CI = 0.08–0.74), respectively. Data Conclusion Our Neurovascular Coil Protocol has high sensitivity, specificity, and accuracy in identifying IPH and LRNC but is limited in assessment of TRFC. Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.