Abstract 687: The Size of Soft Regions in Carotid Atherosclerotic Lesions is Associated With the Presence of Intraplaque Hemorrhage or Ulceration: An Ultrasound Elasticity Imaging and Multi-contrast Weighted MRI Pilot Study
Purpose: Prospective studies using multi-contrast weighted MRI have shown that intraplaque hemorrhage and ulceration in carotid atherosclerotic lesions are associated with higher risk of subsequent cerebrovascular events. This study investigated whether ultrasound (US) elasticity imaging can identify the lesions with intraplaque hemorrhage or ulceration.
Methods: 25 individuals with carotid stenosis of 15–79% were imaged with a 3T MRI and also underwent US scanning. The US and MRI arms were reviewed independently. MR images were reviewed according to previously published criteria to determine the presence of hemorrhage and ulcerations. Radiofrequency US data was used to create elasticity images. A plaque softness ratio (PSR) was computed as a ratio of strain in the atherosclerotic lesion to the average strain in the adjacent adventitia. The area of the soft regions (i.e., PSR>2) was computed as percentage of the total lesion area.
Results: Of 28 arteries with lesions, 7 were excluded (US 4, MR 3) due to inadequate image quality; 21 arteries were analyzed. MRI review found intraplaque hemorrhage in 5 arteries while a sixth had an ulcerated lesion. In US elasticity images, these 6 had significantly larger soft regions than 15 arteries without hemorrhage or ulceration (single-sided t-test, p<0.0013). Using an area threshold of 38%, the sensitivity of detecting lesions with hemorrhage or ulceration using US elasticity was 80% at a specificity of 100%.
Conclusion: We have previously validated US elasticity imaging with histopathology. US elasticity imaging also shows promise as a method to noninvasively identify atherosclerotic lesions with hemorrhage or ulceration.