ECG-gated acquisition of 3D IVUS image sets is feasible and permits the application of automated contour detection to provide reproducible measurements of the lumen and atherosclerotic plaque CSA and volume in a relatively short analysis time.

Intravascular ultrasound (IVUS), which depicts both lumen and plaque, offers the potential to improve on the limitations of angiography for the assessment of the natural history of atherosclerosis and progression or regression of the disease. To facilitate measuremenk and increase the reproducibility of quantitative IVUS analyses, a computerized contour detection system was developed that detects both the luminal and external vessel boundaries in 3dimensional sets of IVUS images. To validate this system, atherosclerotic human coronary segments (n = 13) with an area obstruction ~~40% (40% to 61%) were studied in vitro by IVUS. The computerized IVUS measurements (areas and volumes) of the lumen, total vessel, plaque-media complex, and percent obstruction were compared with findings by manual tracing of the NUS images and of the corresponding histologic cross sections obtained at 2-mm increments (n = 100). Both area and volume measurements by the contour detection system agreed well with the results obtained by manual tracing, showing low mean betweenmethod differences (-3.7% to 0.3%) with SDS not exceeding 6% and high correlation coeffrcienk (r = 0.97 to 0.99). Measurements of the lumen, total vessel, plaque-media complex, and percent obstruction by the contour detection system correlated well with histomorphometry of areas (r = 0.94,0.88,0.80, and 0.88) and volumes (r = 0.98,0.91,0.83, and 0.91). Systematic dii ferences between the resulk by the contour detection system and histomotphometry (29%, 13%, -%, and -22%, respectively) were found, most likely resulting born shrinkage during tissue fixation. The resulk of this study indicate that this computerized tVUS analysis sys tern is reliable for the assessment of coronary atherosclerosis in vivo. 0 7 996 by Excerpta Medica, Inc. (Am J Cardiol 1996;78: 1202-1209 Th e natural history and progression or regression of coronary atherosclerosis after pharmacologic and nonpharmacologic interventions have most often been assessed by quantitative coronary angiographyk3 However, the quantitative angiographic approach permits only the assessment of the luminal silhouette4 and indirect estimation of plaque burden. As a result of vessel remodeling, early atherosclerosis remains angiographically undetected until luminal encroachment starts and plaque occupies approximately 40% of the internal elastic membrane area.5 Intravascular ultrasound (IVUS) depicts both coronary lumen and vessel wall; measurements can be obtained by manually tracing the luminal and ex- ternal vascular boundaries.6-8 To reduce the time and subjectivity of manual tracing,' automated systems for quantitative analysis in 3-dimensional IVUS image sets have been developed.'0-14 As the available systems detect only the lumen, we developed a contour detection algorithm that detects both the luminal and external vascular boundaries of atherosclerotic coronar sets.'591 2 arteries in 3-dimensional IVUS image This approach allows the quantification of all IVUS images and permits even volumetric assessment which ha...

ECG-gated image acquisition after coronary stent deployment is feasible, permits on-line automated 3D reconstruction and analysis and provides reliable and reproducible measurements; these factors facilitate detection of the minimal lumen site.

Carotid artery stenting is a rapidly evolving method for treating carotid artery disease. Various intraprocedural and postprocedural complications have been reported in the literature. However, the absence of a unified classification scheme for these complications makes it difficult, if not impossible, to study their precise incidence, predictors, and management. The aim of this article is to propose the first joint classification of periprocedural complications, to analyze their incidence and etiology, and suggest possible ways to manage and prevent them. This classification is intended to be used as a common platform for prompt recognition, evaluation, treatment, and universal study of the complications during carotid stenting procedures. For this purpose, the opinions of the major experts on carotid interventions worldwide were merged with all the available information reported in the English-language literature to present as accurately as possible the management and prevention of carotid stenting complications according to this proposed classification.