Influence of heart rate on the detectability and reproducibility of multislice computed tomography for measuring coronary calcium score using a pulsating calcified mock-vessel in comparison with electron beam tomography.
BACKGROUND
The influence of heart rate on detectability and reproducibility of multislice computed tomography (MSCT) for measuring coronary calcium score was evaluated using pulsating calcified mock-vessels and compared with electron beam tomography (EBT).


METHODS
Four calcified mock-vessels with 200-350 HU were made to pulsate at a rate of 40-80 beat/min. Retrospective ECG-gating MSCT (Light Speed Ultra 16) scanning with 0.625 mm slice-thickness was performed twice at each pulsation rate. For comparison, EBT (Imatron C150 XP) was performed with 3 and 1.5 mm beam collimation with prospective ECG-gating and calcium scores were measured.


RESULTS
The comparison revealed that MSCT did not have better reproducibility than EBT, but the calcium scores with MSCT were less influenced by pulsation rates than those with EBT. Especially in mild calcification, the calcium scores decreased with EBT with 3 mm beam collimation with increasing pulsation rate, but the scores were stable in any rate with MSCT.


CONCLUSIONS
MSCT effectively detects coronary calcification, especially mild calcification, without being influenced by heart rate. This is accomplished by reducing the partial volume effect in the through plane using sub millimeter slice thickness, and using appropriate reconstruction methods, which improve temporal resolution.
Funabashi
Nobusada
N
Koide
Kikuyo
K
Mizuno
Naoko
N
Nagamura
Kentaro
K
Ochi
Shigehiro
S
Yanagawa
Noriyuki
N
Okamoto
Yumiko
Y
Uno
Kimiichi
K
Komuro
Issei
I
D002114:Calcinosis / Q000175:diagnosis*; D003327:Coronary Disease / Q000175:diagnosis*; D006339:Heart Rate; D006801:Humans; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards