A three-dimensional quantitative analysis of restenosis parameters after balloon angioplasty: comparison between semi-automatic computer-assisted planimetry and stereology

Abstract

Semi-automatic computer-assisted planimetry is often used for the quantification of restenosis parameters after balloon angioplasty although it is a time-consuming method. Moreover, slicing the artery to enable analysis of two-dimensional (2-D) images leads to a loss of information since the vessel structure is three-dimensional (3-D). Cavalieri's principle uses systematic random sampling allowing 3-D quantification. This study compares the accuracy and efficiency of planimetry versus point-counting measurements on restenosis parameters after balloon angioplasty and investigates the use of Cavalieri's principle for 3-D volume quantification. Bland and Altman plots showed good agreement between planimetry and point counting for the 2-D and 3-D quantification of lumen, internal elastic lamina (IEL) and external elastic lamina (EEL), with a slightly smaller agreement for intima and media. Mean values and induced coefficients of variation were similar for both methods for all parameters. Point counting induced a 6% error in its 3-D quantification, which is negligible in view of the biological variation (>90%) among animals. However, point counting was 3 times faster compared to planimetry, improving its efficiency. This study shows that combining Cavalieri's principle with point counting is a precise and efficient method for the 3-D quantification of restenosis parameters after balloon angioplasty.