Stereology: a simplified and more time-efficient method than planimetry for the quantitative analysis of vascular structures in different models of intimal thickening.
OBJECTIVE
Semiautomatic computer-assisted planimetry is currently the standard morphometric technique in models of intimal thickening. We evaluated stereological point counting as an alternative method for the measurement of cross-sectional vascular areas (lumen, intima, and media) by comparing precision, efficiency, and variance components.


METHODS
Sections from murine atherosclerotic aorta (n = 21), stented rabbit iliac arteries (n = 30), and porcine coronary arteries (n = 30) were analyzed at two institutes using both techniques. To determine reproducibility, porcine arteries were measured twice.


RESULTS
Area measurements showed almost identical means and standard deviations for planimetry and stereology [e.g., intima (mm2): 0.10+/-0.11 vs. 0.12+/-0.12 (mouse), 0.60+/-0.16 vs. 0.60+/-0.15 (rabbit), and 1.92+/-1.52 vs. 1.97+/-1.61 (pig)]. Deming regression and Bland-Altman plots demonstrated a good agreement between both techniques that was not influenced by artery size. Both methods exhibited excellent repeatability, although planimetry (-0.18+/-0.27) was more precise than stereology (-0.17+/-0.47; variance, P < .01, Levene test). In addition, intraoperator variance (error inherent to the technique) was greater for stereology (1.6-15.8% vs. 4.8-33.5%), whereas interoperator variance (error between institutes) was very small for both methods (0.1-0.9% vs. 0.1-1.7%). Indeed, biologic variability was, by far, the most important variance component in all measurements (84-98% vs. 65-95%). Finally, stereology required 20% (mouse; P < .05) to 40% (pig; P < .001) less time to complete analysis.


CONCLUSIONS
The quantification of vascular structures by planimetry and stereology yielded comparable results in all models of intimal thickening, but stereology proved to be less time-consuming. Therefore, study design may dictate the most appropriate choice of technique.
Van Vré
Emily A
EA
Division of Cardiology, University of Antwerp, Wilrijk, Belgium. emily.vanvre@ua.ac.be
van Beusekom
Heleen M
HM
Vrints
Christiaan J
CJ
Bosmans
Johan M
JM
Bult
Hidde
H
Van der Giessen
Willem J
WJ
D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology; D050197:Atherosclerosis / Q000473:pathology*; D003331:Coronary Vessels / Q000473:pathology; D004195:Disease Models, Animal; D007083:Iliac Artery / Q000473:pathology; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D051379:Mice; D018345:Mice, Knockout; D011817:Rabbits; D015203:Reproducibility of Results; D013552:Swine; D017539:Tunica Intima / Q000473:pathology*