More than 500 post-mortem cases were analysed with PMCT of MPMCTA in our centre. PMCT reveals the presence of coronary artery calcification. MPMCTA additionally allows for the evaluation and documentation of coronary artery lumina, and the detection of myocardial lesions such as myocardial rupture, and in some cases, myocardial infarction.

The most essential component of MPMCTA in the evaluation of the coronary arteries is to compare the different phases of angiography, specifically the arterial and dynamic phase. Any stenosis or occlusion of a coronary artery, visible in the arterial phase of MPMCTA has to be searched for and verified in the dynamic phase, as residual blood in the vessels can mimic a true stenosis. The analysis of the coronary arteries in PMCTA needs to be done very carefully by using axial and reconstructed images such as multi-planar reconstruction (MPR) or maximum intensity projection (MIP) as well three-dimensional reconstructions to allow examination of the vessels in different views and avoid misinterpretation concerning the presence or absence of vital occlusion (Figs 2-4). For living patients, it is recommended that the radiological diagnosis and the evaluation of stenosis should not be done based on 3D-VRT images. However, in deceased patients, we do not have the problem of artefacts due to heart motion, and a relatively high resolution of the images can be obtain, as there is no limit for radiation dose. Therefore, the 3D-images represent a useful and rapid tool to obtain a general overview of the coronary tree and the location of the suspected stenosis, prior to the classical autopsy.

Sudden cardiac death related to atherosclerotic coronary artery disease is most frequently related to thrombotic occlusion, which is identified in post-mortem examination. From the pathological point of view, coronary thrombosis is most frequently due to plaque rupture or plaque erosion. In our  series of sudden cardiac deaths related to atherosclerotic coronary artery disease  which was recently published, the individuals with plaque erosions were younger than those with ruptures (mean ages 46.73±8.33 versus 58.23±10.62 years). We observed that 82% of ruptures and 77% of erosions were found in the proximal segments of the main coronary arteries. Erosions were most frequently observed in the left anterior descending artery  (61.5%), while ruptured plaques were more homogeneously distributed in all coronary arteries.

Our observations concerning radiological evaluation of eroded plaques suggest that the only visible sign in PMCTA seems to be the presence of a focal stenosis, sometimes with a focal “enlargement” of the vessel just before the stenosis, which may be subtle radiologically such that its significance may be overlooked. We noticed that coronary arteries with eroded plaques are less calcified than those with ruptured plaques. The cap thickness is considered to be the best discriminator of plaque vulnerability, but the spatial resolution of MDCT is too low to make an accurate determination. Therefore, the exact morphological etiology of a luminal stenosis or occlusion (plaque rupture, plaque erosion, etc.), and the age of the infarction have to be evaluated histologically. In post-mortem radiological evaluation of coronary arteries to date at our institute, modern radiological software is not available for precise analysis of coronary artery stenosis. For this reason, data obtained from post mortem analyses is currently less precise than that obtained from living patients. However, thanks to a detailed comparison between radiological image, autopsy and histology, we were able to develop a specific key for postmortem radiological reading of coronary arteries (Fig 5).