Evaluation of cholesterol crystals in carotid plaque by dual energy computed tomography

Cholesterol crystals (CCs) in carotid plaques might be an indicator of vulnerability, although they have not been fully investigated and non-invasive methods of assessment have not been established. This study examines the validity of assessing CCs using dual-energy computed tomography (DECT) that uses X-rays with different tube voltages for imaging, allowing material discrimination. We retrospectively evaluated patients who had undergone preoperative cervical computed tomography angiography and carotid endarterectomy between December 2019 and July 2020. We developed CC-based material decomposition images (MDIs) by scanning CCs crystallized in the laboratory using DECT. We compared the percentage of CCs in stained slides defined by cholesterol clefts with the percentage of CCs displayed by CC-based MDIs. Thirty-seven pathological sections were obtained from 12 patients. Thirty-two sections had CCs; of these, 30 had CCs on CC-based MDIs. CC-based MDIs and pathological specimens showed a strong correlation. Thus, DECT allows the evaluation of CCs in carotid artery plaques.