A new probability mapping method to describe the development of atherosclerotic lesions in cholesterol-fed rabbits

A new probability mapping method was developed to quantify the size and location of lesions near aortic orifices. The precise location of any part of the lesion could be compared between rabbits. Colour photographs of lesions were projected onto a digitizing tablet, and coded as lesion or non-lesion. Next the orifices were warped onto a standard orifice, and then the lesion mapped to maintain the original length and angular location of the lesion from the edge of the orifice. This method, unlike the previously used polar mapping method, excludes neither absent lesions nor ones which surround more than one orifice. In contrast to other probability mapping methods it warps the orifice rather than the artery wall containing the lesion, and so is easier to use for correlation with histological studies. The eventual aim is to use the probability maps as a tool to estimate the age of various positions of the lesion and to identify areas for histological sampling. The method was used to describe the distribution of lesions in 21 rabbits fed a diet with cholesterol levels declining from 0.5% during the first week, to 0.25% during the next two weeks, to 0.125% for weeks 3-10, to 0.1% for weeks 11-24. This feeding protocol produces fatty lesions which are transformed into fibro-fatty and fibrous lesions with time.