Relative value of normalized sonographic in vitro analysis of arteriosclerotic plaques of internal carotid artery.
OBJECTIVE
A close correlation between B-mode sonography and the histopathology and surface structure of plaque is rarely seen in vivo with high-grade stenoses of the extracranial carotid artery. The goal of this study was to determine whether normalized gray scale analysis and surface analysis of the plaque are capable of characterizing the attributes correctly.


METHODS
Optimized B-mode images of 107 carotid endarterectomy specimens were captured, and the gray scale median (GSM) was calculated. The specimens were classified histologically into 3 groups: (1) calcium-rich hard plaques, (2) lipid-rich soft plaques, and (3) combined plaques. The surfaces of the plaques were classified as smooth or rough on the basis of standardized reference samples. The endoluminal surface was digitally documented in vitro by videoendoscopy and again classified into the same categories. All stages of the investigation were performed by 2 observers at 2 different times.


RESULTS
Evaluation of the GSM showed close interobserver and intraobserver correlation (P<0.01, R>0.8). However, there was only 46% agreement between the GSM and the histopathological findings. In both in vitro angioscopy (kappa=0.936, P<0.001) and sonographic evaluation (kappa=0.842, P<0.001), there was a high correlation between the observers with regard to the evaluable specimens. In 73%, agreement was observed between the sonographic image and angioscopy.


CONCLUSIONS
Normalized gray scale analysis and evaluation of the plaque surface in an in vitro study make possible observer-independent evaluation. The composition of the plaque cannot be visualized with sufficient accuracy by sonographic GSM analysis. This also applies to the correlation between sonography and actual surface composition of the plaque.
Denzel
Christian
C
Section of Vascular Surgery, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
Balzer
Klaus
K
Müller
Klaus-Michael
KM
Fellner
Franz
F
Fellner
Claudia
C
Lang
Werner
W
D000368:Aged; D001161:Arteriosclerosis / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002340:Carotid Artery Diseases / Q000473:pathology / Q000601:surgery; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D016894:Endarterectomy, Carotid; D004724:Endoscopy; D005260:Female; D005557:Formaldehyde; D006801:Humans; D008297:Male; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D016707:Tissue Fixation; D014463:Ultrasonography / Q000379:methods*
D005557:Formaldehyde