Influence of a small field-of-view size on the detection of coronary artery calcifications with MSCT: in vitro and in vivo study.

The purpose of this study is to asses the impact of small field-of-view (FOV) sizes on the detection of coronary artery calcifications using multislice-spiral computed tomography (MSCT). First, a static chest phantom containing calcium inserts was scanned 10 times using a standardized scan protocol. Secondly, 50 patients (28 male, 63.6+/-10.6 years) underwent cardiac MSCT using the same protocol. Images were reconstructed with three different FOV sizes (180x180, 220x220, 380x380 mm(2)). Coronary calcium scoring and risk stratification were performed for each image series. In the phantom study, the Agatston score calculated with a FOV size of 180x180 mm(2) was 657.80+/-20.05. At a FOV of 220x220 mm(2) and 380x380 mm(2), the corresponding values were 657.04+/-21.36 and 655.04+/-20.74, respectively. The corresponding values in the patient study were 541.65+/-869.87, 541.91+/-872.57 and 536.61+/-867.81. No statistically significant differences in the calcium score were found comparing different FOV sizes. Significantly more lesions (p=0.00149) were detected in the patient study. Comparing the different FOV sizes of 180x180 mm(2) and 220x220 mm(2) (380x380 mm(2)), four (six) patients had to be assigned to different risk groups. The use of small FOV sizes resulted in an improved detection of coronary calcifications influencing the risk stratification for further cardiac events in MSCT coronary calcium scoring.