Non-invasive characterisation of coronary lesion morphology and composition by multislice CT: first results in comparison with intracoronary ultrasound

The reliable non-invasive detection of coronary artery disease (CAD) is a p rime goal for future developments in clinical cardiology. In addition to th e documentation of high-grade stenoses, the detection of vulnerable plaques is of major importance for risk stratification and early treatment to prev ent plaque rupture. Recently, a new generation of fast spiral CT has been i ntroduced using a multi-slice technique (MSCT), which is the first real qua ntum leap in CT since the introduction of spiral CT in the early 1990s. We report on non-invasive differentiation of coronary plaque morphology by MSC T in patients with lesions in the proximal left anterior descending artery (LAD). The results were compared with the findings of intracoronary ultraso und (ICUS). The ICUS and MSCT scans were analysed in 6 patients scheduled f or ICUS-guided PTCA. One target lesion was selected in each patient. On ICU S, two lesions were classified as soft, two as intermediate and two as calc ified according to established criteria based on echogenicity. By multislic e CT, density measurements (expressed in Hounsfield Units, HU) were perform ed at 16 randomly selected areas within the plaques. The two soft plaques s howed a mean density of 6 +/- 28 and -5 +/- 25 HU, the two intermediate pla ques of 83 +/- 17 and 51 +/- 19 HU, and the two calcified plaques of 489 +/ - 372 and 423 +/- 111 HU. To our knowledge, this is the first report on non -invasive characterisation of coronary lesions by MSCT. Plaque composition could be clearly differentiated and classified according to the ICUS result s by determining tissue density within the lesions. Thus, this new technolo gy holds promise for noninvasive risk assessment in patients with known or suspected CAD since also rupture-prone soft coronary lesions can be detecte d by use of this new technique.