Hermann Franziska, Martinoff Stefan, Meyer Tanja, Hadamitzky Martin, Jiang Chaohui, Hendrich Eva, Hausleiter Jörg
Institut für Radiologie und Nuklearmedizin, Deutsches Herzzentrum München, München, München, Germany.
Invest Radiol. 2008 Apr;43(4):253-60. doi: 10.1097/RLI.0b013e318160b3a3.
The objectives of this prospective investigation in patients after bypass graft surgery were (1) to estimate radiation dose for routine bypass graft computed tomography (CT) angiography, (2) to study the impact of anatomically adapted and ECG-controlled tube current modulation on radiation dose estimates, and (3) effects on qualitative and quantitative image quality parameters.
Radiation dose was estimated for 194 consecutive patients undergoing 64-slice CT angiography (Somatom Sensation 64 Cardiac, Siemens Medical Solutions). The impact of anatomically adapted tube current modulation was studied in 2 consecutive patients groups. Furthermore, the impact of ECG-controlled tube current modulation, applied as indicated, was evaluated in both groups.
Mean radiation dose estimate for a 64-slice CT bypass graft study was 18.9 +/- 6.0 mSv (CTDIvol 42.3 +/- 12.9 mGy). The application of anatomically adapted tube current modulation had no effect on dose parameters (CTDIvol 43.3 +/- 13.2 vs. 40.1 +/- 12.1 mGy for those with versus those without anatomically adapted tube current modulation, P = 0.1). Additional implementation of ECG-controlled tube current modulation resulted in reduced dose parameters (CTDIvol of 32.9 +/- 2.6 vs. 58.9 +/- 3.9 mGy and radiation dose estimates: 14.7 +/- 1.9 mSv vs. 26.5 +/- 2.1 mSv for those with versus those without ECG pulsing, both P < 0.01). There was no deterioration in image quality with use of tube current modulation algorithms.
The radiation burden associated with 64-slice bypass graft CT angiographies is substantial. Anatomically adapted tube current modulation does not reduce radiation dose parameters, whereas ECG-controlled tube current modulation was associated with a 45% reduction in dose estimates. Application of both tube current modulation algorithms did not result in reduced image quality.
本前瞻性研究针对搭桥手术后患者的目的包括：（1）估算常规搭桥血管计算机断层扫描（CT）血管造影的辐射剂量；（2）研究解剖适应性和心电图控制的管电流调制对辐射剂量估算的影响；（3）对定性和定量图像质量参数的影响。
对194例连续接受64层CT血管造影（Somatom Sensation 64 Cardiac，西门子医疗解决方案公司）的患者估算辐射剂量。在2个连续患者组中研究了解剖适应性管电流调制的影响。此外，在两组中均评估了按指示应用的心电图控制管电流调制的影响。
64层CT搭桥血管研究的平均辐射剂量估算值为18.9±6.0 mSv（CTDIvol为42.3±12.9 mGy）。解剖适应性管电流调制的应用对剂量参数无影响（有解剖适应性管电流调制者的CTDIvol为43.3±13.2 mGy，无解剖适应性管电流调制者为40.1±12.1 mGy，P = 0.1）。额外实施心电图控制的管电流调制导致剂量参数降低（有心电图脉冲者的CTDIvol为32.9±2.6 mGy，无心电图脉冲者为58.9±3.9 mGy；辐射剂量估算值：有心电图脉冲者为14.7±1.9 mSv，无心电图脉冲者为26.5±2.1 mSv，两者P均<0.01）。使用管电流调制算法时图像质量没有下降。
64层搭桥血管CT血管造影相关的辐射负担很大。解剖适应性管电流调制不会降低辐射剂量参数，而心电图控制的管电流调制可使剂量估算降低45%。两种管电流调制算法的应用均未导致图像质量下降。
