[Detection of coronary calcinosis with multislice spiral computerized tomography: an alternative to electron beam tomography]. / Detektion von Koronarkalk mit der Mehrschicht-Spiral-Computertomographie: Eine Alternative zur Elektronenstrahltomographie.

ABSTRACT

Electron-beam CT (EBT) has been used for years as the gold standard to quantify coronary artery calcification as a marker of coronary atherosclerosis. With the introduction of Multi-Slice Spiral CT (MSCT) technology in 1999, EBT is now challenged in the determination of coronary calcium. The aim of this study was to determine the diagnostic accuracy of MSCT for the assessment of coronary calcium, comparing this new technique to EBT. The study population consisted of 54 male patients, aged 58 +/- 11 years with suspected coronary artery disease. For EBT, 40 axial slices (scan time = 100 ms, slice thickness = 3 mm) were acquired in one breath-hold (35 +/- 5 s) using an ECG-trigger at 80% of the RR interval. For MSCT, simultaneous acquisition of four axial slices (scan time = 250 ms, slice thickness = 2.5 mm) allowed the entire heart (40 slices) to be covered in one breath-hold (25 +/- 5 s) using a prospective ECG-trigger (R--450 ms). For quantification of coronary calcium the Agatston and the Volumetric calcium score (VCS) were applied. Mean Agatston score of the study group was calculated as 88 +/- 111 (median = 45), which is between the 25th and 75th age-corrected percentile of asymptomatic patients. For the Volumetric calcium score, number of lesions, calcium mass and density, no statistical difference was found between both imaging modalities. Agatston and Volumetric calcium score were statistically different between and within both scans. Mean variability of VCS of the two methods was calculated as 24% and was in the range of repeated EBT studies (14-44.9%). The Multi-Slice Spiral CT scanner is equivalent to EBT for the determination of coronary calcium and can, therefore, be used for calcium screening. Using a prospective ECG-trigger technique, the application of the Agatston method delivers statistically different results in comparison to EBT. With the application of the spiral mode technique, retrospective ECG-trigger and thinner slice thickness, further improvement in variability can be expected, thus allowing for follow-up studies to determine progression or regression of atherosclerosis with high accuracy.