MDCTA demonstrated good interobserver agreement (κ=0.751) for carotid plaque characterization, but only moderate agreement (κ=0.595-0.624) with DUS, which yielded higher stenosis values.
Does MDCTA demonstrate reliable interobserver and intermodality agreement with DUS for evaluating carotid plaque characteristics in patients with ≥60% stenosis?
MDCTA provides reproducible carotid plaque characterization between observers, but yields systematically lower stenosis and plaque length measurements compared to DUS, highlighting the need to account for modality-specific differences in clinical decision-making.
Background and Objectives: Carotid artery stenosis has traditionally guided therapeutic decision-making; however, plaque morphology and composition are increasingly recognized as more reliable indicators of cerebrovascular risk than luminal narrowing alone. As imaging strategies shift toward vulnerability-based assessment, reproducibility of plaque characterization becomes essential for consistent clinical decision-making. This study aimed to evaluate interobserver agreement in carotid plaque assessment using multidetector computed tomography angiography (MDCTA) and to assess intermodality agreement with duplex ultrasonography (DUS). Materials and Methods: In this single-center study (January–September 2022), 50 patients with ≥60% internal carotid artery stenosis diagnosed by DUS (NASCET criteria), the majority of whom were asymptomatic (90%), were included. MDCTA examinations were independently analyzed by two radiologists, while DUS examinations were evaluated by a third observer. Plaque composition (lipid, fibrous, calcified), surface characteristics (regular, irregular, ulcerated), degree of stenosis, and plaque length were assessed. CT plaque characterization was based on Hounsfield unit (HU) thresholds (120 HU calcified). Interobserver agreement and intermodality agreement were calculated using Cohen’s kappa coefficient. Results: Good interobserver agreement was observed between the two MDCTA readers (κ = 0.751). Intermodality agreement between MDCTA and DUS was moderate (κ = 0.624 and κ = 0.595). Although significant differences were identified in 3 of 16 HU measurement points, no significant differences were found in overall plaque composition classification between MDCTA observers. DUS yielded significantly higher stenosis values (p = 0.007 and p = 0.005) and greater plaque length measurements (p < 0.0005) compared with MDCTA. Significant differences were also observed in plaque surface assessment between modalities (p = 0.044 and p = 0.033). Conclusions: MDCTA demonstrates good interobserver reproducibility for carotid plaque characterization, while intermodality agreement between MDCTA and DUS is moderate. Minor attenuation measurement differences do not significantly affect plaque classification; however, systematic intermodality differences in stenosis grading, plaque surface evaluation, and plaque length measurement should be considered in clinical decision-making.
Mutavdžić et al. (2026) studied this question. MDCTA demonstrated good interobserver agreement (κ=0.751) for carotid plaque characterization, but only moderate agreement (κ=0.595-0.624) with DUS, which yielded higher stenosis values.