Calcified plaque cross-sectional area in human arteries: correlation between intravascular ultrasound and undecalcified histology.
BACKGROUND
The purpose of this investigation was to quantify the amount of intralesional calcium detected by intravascular ultrasound (IVUS) compared with undecalcified histology in human arteries. This method preserves intralesional calcium and reduces sectioning artifacts, thereby providing an accurate measure of calcium plaque morphology.


RESULTS
Ten arterial segments (5 coronary, 5 iliac) were obtained at autopsy. IVUS imaging was performed with a 4.9F catheter at an automated pullback rate of 1.0 mm/s. The undecalcified arteries were dehydrated in ascending alcohol and polymerized in glycol methylmethacrylate. The arteries were cut into 200-microm sections with an Isomet low-speed saw and stained with Goldner's trichrome. The lumen cross-sectional area, the calcium plaque cross-sectional area, the calcium plaque depth, length, and angle of arc of calcified plaque were measured from the IVUS images and histologic sections. In 24 selected cross sections, there were 38 separate calcium plaques. An independent observer correctly identified 34 of 38 calcified plaques for a sensitivity of 89% and specificity of 97%. The total mean calcified plaque cross-sectional area measured from histology was 4.6 +/- 4.1 mm2 compared with 2.8 +/- 2.3 mm2 by IVUS (P =.002). Plaque depth measured by histology was 1.2 +/- 0.4 mm versus 0.7 +/- 0.2 mm by IVUS (P =.001). The length of calcium plaques measured by histology was 3.6 +/- 1.78 mm versus 3.6 +/- 1.5 mm for IVUS (r = 0.79).


CONCLUSIONS
IVUS accurately depicts circumferential calcified lesions with high sensitivity (89%) and specificity (97%). However, IVUS underestimates the total calcified plaque cross-sectional area by 39%. This is mainly because of the inability of the ultrasound to penetrate intralesional calcium, which leads to an underestimation of the depth of calcium by 45%.
Division of Cardiology, University of California, Irvine, Orange, Calif., USA.
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H
Kostamaa
J
J
Donovan
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S
Kasaoka
J
J
Tobis
L
L
Fitzpatrick
D000328:Adult; D000368:Aged; D019412:Anatomy, Cross-Sectional; D001161:Arteriosclerosis / Q000000981:diagnostic imaging* / Q000473:pathology; D016477:Artifacts; D001391:Azo Compounds; D002102:Cadaver; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000473:pathology; D002118:Calcium; D004396:Coloring Agents; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000473:pathology; D004801:Eosine Yellowish-(YS); D004852:Epoxy Compounds; D000431:Ethanol; D005260:Female; D005404:Fixatives; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000473:pathology; D007091:Image Processing, Computer-Assisted; D008297:Male; D008689:Methacrylates; D008739:Methyl Green; D008867:Microtomy; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional
D001391:Azo Compounds; D004396:Coloring Agents; D004852:Epoxy Compounds; D005404:Fixatives; D008689:Methacrylates; C017768:trichrome stain; D000431:Ethanol; D008739:Methyl Green; C007870:glycidyl methacrylate; D002118:Calcium; D004801:Eosine Yellowish-(YS)