中文摘要：

目的评价128排螺旋CT低剂量前门控心脏冠状动脉扫描成像的图像质量与辐射剂量，并与常规剂量前门控冠状动脉扫捕成像对照分析。方法应用前瞻性心电门控管电流调冉模式进行冠状动脉成像，将60例患者随机分为常规剂量组和低剂量组（各30例），常规剂量组扫描条件为120kV／200mAs，低剂量组扫捕条件为120kV／100mAs。对2组扫描结果分别做图像后处理，闭像质城主观评价由2位有经验的副主任医师承担，同时测量2组的信噪比（SNR）、对比噪声比（CNR），并计算受检者的辐射剂量。结果60例患者中，主观评价常规剂量组图像质量优者为23例（77％）和中等质量为7例（23%），低剂量组图像质量优为22例（73％）和中等质量为8例（27％）；2组比较无明显统计学意义（P〉0．05）。常规剂量组图像SNR值为22．14±8．52，低刹量组图像SNR值为17．08±5．27，2组比较无统计学意义（P〉0．05）；常规剂量组CNR值为13．96±3．52，低剂量组CNR值为13．04±4．05，2组比较无统计学意义（P〉0。05）。低剂量组受检者辐射剂量为（1．72±0．17）mSv，常规剂量组受检者辐射剂量为（2．85±0．45）mSv，2组间比较有显著统计学意义（t=7．932，P〈0．05）。结论128排螺旋CT低剂量前门控冠状动脉成像能有效降低受枪者的辐射剂量，同时不影响图像质量。

英文摘要：

Objective To evaluate image quality （IQ） and radiation dose for 128-row low-dose prospective electrocardiogram （ECG）-gated computed tomography coronary anhiography （CTCA） compared with conventional prospective electrocardiogram （ECG） gated CTCA. Methods Prospective ECG- gating CTCA was used with regulating current in this study. A total of 60 patients were assigned to two groups： conventional group （120 kVp, 200 mAs） and low-dose group （120 kVp, 100 mAs）, with 30 patients in each group. The images of two groups were reprocessed. The quality was evaluated by two experienced reviewers. Signal to noise （SNR） , contrast to noise （CNR） ratio and the radiation doses were calculated and evaluted. Results Among 60 patients, IQ was good in 23 eases （77%） and moderate in 7 cases （23 %） from the conventional prospective ECG-gated group; IQ was good in 22 ca ses （ 73 % ） and moderate in 8（ 27 % ） in the low-dose prospective ECG-gated group. There was no significant difference （ P〉0.05 ） between conventional group and low dose group for SNR （22.14±8. 52 vs. 17.08±5.27） and CNR （13. 96±3. 52 vs. 13. 04±4.05）. The mean effective radiation dose in the low-dose prospective ECG-gated group was （1.72±0. 17） mSv, which was signifi cantly lower than that（2.85 mSv±0.45 mSv） of the conventional prospective ECG-gated group （t 7. 932 , P〈0. 05 ）. Conclusion I.ow-dose prospective ECG-gated of 128 row CTCA provides same image quality with significant lower radiation dose compared with conventional prospective ECG-gating of 128 row CTCA.