An Objective Characterization of Atherosclerotic Lesion

Abstract

Background and Purpose-The aim of this study was to evaluate a computer-assisted technique to characterize atherosclerotic plaque. Methods-In 9 subjects (7 men, 2 women; mean age 33 years), known anatomic areas (carotid, fat, muscle, iliotibial tract, and tibia) were scanned with an Acuson duplex ultrasound machine with 72 machine settings. The ultrasound images of these anatomic areas were recorded on magneto-optical disks. Echo amplitude statistics were obtained, and the mean pixel value (MPV) was used to assess the level of echogenicity. The ideal settings of this particular scanner for optimal discrimination between these tissues types were identified by the Heuristic Index of Discrimination. With these settings, carotid artery scanning was performed on 17 patients (15 men, 2 women; mean age 65 years), and the image analysis of their ultrasound carotid plaques was compared with their histological findings. Results-In this study, discrimination between the selected tissues was found to be optimal when the controls were set at log 40 dB, 0/2/0, and gain of Ϫ5 dB. The MPV of the carotid specimens scanned at this setting correlated significantly with the histological findings (Spearman correlation, Pϭ0.002). Conclusions-Computer-assisted image analysis to give the MPV is a technique that may be used to identify unstable atherosclerotic plaques reliably.

A Critical Appraisal of the Performance, Reporting, and Interpretation of Studies Comparing Carotid Plaque Imaging With Histology

“…90 However, 47 studies (64%) did not reference previously used techniques for any part of the histological methods and 9 (12%) studies only reported 1 histological feature. 20,47,48,53,58,66,69,83,84 Nine studies (12%) 26,30,41,46,52,55,66,69,71 reported reproducibility of the histological assessments, of which 3 studies were by the same author. 30,52,55 Six of the 9 studies assessed area of histological features as continuous vari- …”

Changes in Carotid Atherosclerosis Patterns Detected by Ultrasonography in Japanese Elderly Patients with Aortic Aneurysm

“…El-Barghouty et al reported eported that interrater reliability was excellent (γ = 0.94) and reproducibility was not problematic, using median echogenicity of the carotid lesion analyzed by computer (19). Aly et al also used the mean echogenicity of the carotid lesion, but these methods gave rise to problems in assessing heterogeneous lesions (20). In this study, therefore, the shape of the histogram was used to differentiate heterogeneous lesions from homogeneous lesions (20).…”

“…However, the qualitative assessment of lesions is still unresolved in terms of the reproducibility and interrater reliability, because visual assessment of the le- sion was subjective and it was difficult to compare the qualitative findings directly from lesion to lesion (13)(14)(15)(16)(17)(18). Recently, it has been considered that the computer analysis method can evaluate lesion quality objectively (19)(20)(21). El-Barghouty et al reported eported that interrater reliability was excellent (γ = 0.94) and reproducibility was not problematic, using median echogenicity of the carotid lesion analyzed by computer (19).…”

“…It is also possible to evaluate the histological changes of the lesion to some extent, but subjective assessment of the lesion image usually depends on the ultrasound equipment, the gain settings, and the operator, which gives rise to problems of reproducibility and reliability (13)(14)(15)(16)(17)(18). However, recently, qualitative assessment has become possible by newly-developed, computer image analysis to digitize visual image information (19)(20)(21). We performed computer analysis to clarify recent changes in carotid atherosclerotic lesions.…”

Computerized Assessment of Carotid Plaque Echogenicity before Stenting

“…The eXIstmg classifications were subjective and qualitative and, therefore, the need for a standardized and quantitative method of assessment has been emphasized. In recent years, several investigators have suggested computerized assessment of carotid plaque echogenicity by means of GSV to overcome the sUbjectivity [5][6][7] Recognition of the imaging features that correspond to the histopathologic constituents of carotid plaques associated with increased risk of distal embolization during stenting would be useful deciding on the therapy in individual cases. Ohki et al found an increased risk of distal embolization in lesions that were echo-lucent at transcutaneous US and "soft" at A histopathologic analysis in ex vivo model x.…”