Effects of temperature and histopathologic preparation on the size and morphology of atherosclerotic carotid arteries as imaged by MRI

Using magnetic resonance imaging the effects of temperature, formalin fixation, and decalcification on the size and morphology of atherosclerotic arteries were evaluated. Ten ex vivo carotid arteries were scanned fresh at body and room temperature and formalin-fixed and decalcified at room temperature. Different spin-echo pulse sequences were used and absolute T2 values calculated. During processing for histopathology, the contrast between the arterial layers increased. From body to room temperature there were significant increases in size (4%-7%), T2 of media (60--> 68 msec), and fibrous plaque component (95--> 110 msec). Formalin fixation caused significant increases in size (2%-3%) and media T2 (68--> 74 msec). Decalcification caused significant shrinkage (2%-5%) and decrease in T2 of media (74--> 53 msec) and fibrous plaque component (118--> 76 msec). Thus temperature and preparation have profound effects on contrast, size, and T2 of atherosclerotic arteries. Ex vivo experiments should be performed on fresh specimens at body temperature. J. Magn. Reson. Imaging 1999;10:876-885.