Dual source CT 장비의 high pitch(flash) chest pain protocol을 이용한 dissection검사의 유용성 평가

Assessment for the usefulness of dissection using the high pitch chest pain protocol of dual source CT

목 적 Dual source CT 장비의 high pitch chest pain protocol을 이용하여 ECG gating함으로써 ascending aorta의 blurring을 감소시키고, dissection의 coronary artery 침범유무의 확인과 동시에 환자의 피폭선량을 감소시키고자 하였다. 대상 및 방법 2010년 1월부터 2010년 07월까지 본원을 방문한 환자를 대상으로 Definition Flash, Definition AS+장비와 AAPM 팬텀을 이용하여 dissection 검사자의 CTDI값을 비교분석하였고 Dissection의 전반적인 판독유무를 관찰하였다. 첫 번째 비교대상으로는 ECG gating과 non-ECG gating방법으로 검사하여 Aortic root images을 비교하는 것이다. high pitch(flash) chest pain protocol방법으로 검사한 영상들과 기존의 방식으로 ECG gating 없이 검사한 환자의 Aortic root image의 판독유무를 관찰하였다. 그 두 번째로 high pitch(flash) chest pain protocol로 ECG gating한 방법과 일반적인 chest pain protocol로 ECG gating하여 동일한 AAPM팬텀을 scan 하였다. 이렇게 획득된 팬텀영상을 가지고 동일한 image quality를 가지는 parameter 값을조절하고 Dose량, 즉 CTDI값을 비교해 보았다. 결 과 ECG gating을 함으로 해서 ascending aorta의 blurring은 기존의 Non-ECG gating 검사방법보다 월등하게 감소시킬 수 있었으며 Aortic root의 image quality는 향상되었다. Chest pain protocol과 Flash chest pain protocol을 비교했을 때 noise, uniformity, high contrast resolution의 차이를 보이지 않는 parametar 범위 내에서, high-pitch chest pain protocol로 검사하였을 때CTDI 값이 더욱 더 낮게 나왔으므로 dose reduction에 도이점이 있음을 알 수 있었다. 결 론 Dose reduction을 고려함에 있어 특히 관심의 대상이 되어 왔던 분야는 cardiac이었다. 이러한 cardiac분야의 dose reduction mode를 이용하여 dissection과 같은 진단분야에 응용하여 적용한다면 획기적인 피폭선량 감소 효과 뿐만 아니라 빠른진단과 함께 신속한 치료가 필요한 환자들에게 매우 중요한 검사방법이 될 것으로 사료된다.

Ⅰ. Purpose It is to decrease motion artifacts of blurring on the image of the ascending aorta and to decline exposed dose. In addition, it is to confirm invasion of dissection on coronary artery. Ⅱ. Materials and Methods This study was given to a sample of patients visiting the hospital for dissection from January 2010 to July 2010. The CTDI and DLP values of the examination were compared and analyzed which were from AAPM scanned by Definition Flash and Definition AS+. Moreover, the image qualities of the ascending aorta were observed in a diagnostic point of view. Firstly, aortic root were compared on the images between ECG gating and Non-ECG gating. It is to observe the images of ascending aorta by ECG gated high pitch chest pain protocol against existing Non-ECG gated dissection protocol. Secondly CTDI and DLP values were compared between high pitch chest pain protocol and chest pain protocol. Both of them were ECG gated. AAPM was scanned in two methods. The parameters of both scan were adjusted to make the images to the same quality then the CTDI and DLP values were measured in both of the ways. Ⅲ. Results The method with ECG gating reduced motion artifacts of ascending aorta compared to non-ECG gating. Therefore, image quality of aortic root was developed. In the method of high-pitch chest pain protocol, CTDI and DLP were half smaller than the values scanned by general chest pain protocol. Accordingly, it has also advantage in dose reduction. Ⅳ. Conclusion According to dose reduction, hot issue was about cardiac. So, various methods scanning cardiac for dose reduction has developed. Therefore, if these dose reduction modes are applied to something like dissection in diagnostic field, there will be a positive effect on dose reduction as well as fast diagnosis and treatment for many patients.