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[In vitro diagnosis of coronary plaque morphology with intravascular ultrasound: comparison with histopathologic
Insights
This study assessed intravascular ultrasound accuracy in diagnosing coronary artery plaque composition. While effective for calcification and fibrosis, ultrasound struggled with accurate lipid detection, necessitating further technical improvements.
Area of Science:
- Cardiovascular Imaging
- Medical Device Validation
- Histopathology
Background:
- Accurate diagnosis of coronary artery plaque composition is crucial for cardiovascular disease management.
- Intravascular ultrasound (IVUS) is a promising imaging modality, but its accuracy in characterizing plaque components requires validation.
Purpose of the Study:
- To validate the diagnostic accuracy of a commercial intravascular ultrasound system for determining plaque composition in human coronary arteries.
- To evaluate the influence of lipid and calcific deposit patterns on ultrasound diagnostic performance.
Main Methods:
- Human autopsy hearts (n=18) with 35 coronary arteries were used.
- Coronary sections were examined using a Diasonics ultrasound system and compared with histologic findings.
- Ultrasound diagnoses were made based on established criteria, and accuracy was assessed for normal intima, plaque, calcification, and lipid content.
Main Results:
- Ultrasound correctly identified 56% of normal intima sections.
- All 114 plaques were visualized, with high accuracy for calcification (86%) and fibrosis (100%).
- Lipid detection sensitivity varied significantly (26%-73%) with low specificity (30%-92%) depending on the definition used. Overall histologic composition accuracy was 42%.
Conclusions:
- Current intravascular ultrasound technology shows limitations in accurately diagnosing coronary artery plaque composition, particularly lipid content.
- Further technical advancements are required to enhance the reliability of IVUS for detailed plaque analysis.
- While effective for calcification and fibrosis, IVUS needs improvement for precise lipid characterization.
Abstract:
The aim of this study was to validate the accuracy of a commercially available intravascular ultrasound system in diagnosing plaque composition in human coronary arteries. Thirty-five coronary arteries of 18 human autopsy hearts were perfused with NaCl under a pressure of 100 mmHg and examined using a Diasonics ultrasound system and 4.8 F 20 MHz catheters. An ultrasound diagnosis was made of 139 coronary sections using previously published standard criteria and compared with histologic findings. In addition, the influence of the histologic pattern of lipid and calcific deposits on the accuracy of the ultrasound diagnosis was evaluated. Of the 25 sections with a histologically normal intima, 14 (56%) were correctly identified by ultrasound, whereas fibrotic thickening was diagnosed in the remaining 11 sections. There were 114 plaques by histology which were correctly visualized by ultrasound as plaques in all instances. Plaque calcification was correctly diagnosed in 54 of 63 (86%) sections, but massive calcifications were more reliably identified by ultrasound than small speckled calcifications (43/44 = 98% vs 11/19 = 58%, p < 0.001). Fibrosis was present in all 114 plaques and was correctly visualized by ultrasound in all instances. When lipid was diagnosed by ultrasound as a homogeneous zone of low signal intensity within a fibrous plaque as suggested in the literature, lipid accumulations were identified with a sensitivity of 26% (16/62) and a specificity of 92% (71/77). When lipids were diagnosed if more than a quarter of the plaque area showed lower signal intensity than the tissue surrounding the vessel, the sensitivity of ultrasound was improved to 73% (45/62) but specificity fell to 30% (23/77). The entire histologic composition of a section was correctly diagnosed by ultrasound in only 42% of the 139 sections. Further technical improvements are therefore mandatory before intracoronary ultrasound will be able to provide a reliable analysis of plaque composition, especially of the lipid content.