Araki Kazumi, Yoshizako Takeshi, Yoshida Rika, Tada Keiji, Kitagaki Hajime
Department of Radiology, Shimane University Faculty of Medicine, P.O. Box 00693-8501, 89-1 Enyacho, Izumo, Japan.
Department of Radiology, Shimane University Faculty of Medicine, P.O. Box 00693-8501, 89-1 Enyacho, Izumo, Japan.
Clin Imaging. 2018 Sep-Oct;51:352-355. doi: 10.1016/j.clinimag.2018.05.027. Epub 2018 Jun 9.
The purpose of this study was to evaluate the quality of image in abdominopelvic late phase computed tomography (CT) with a low tube voltage plus low dose contrast medium (CM) protocol (80-kVp, 60% CM). A compared with the conventional protocol (120-kVp, 100% CM) B in the same patients.
This study included with 22 patients {36 to 77 kg (mean: 55.5 kg)} who had renal insufficiency and had experience of performance conventional CT without renal insufficiency during pre-18 months. The CT value of the portal vein, liver parenchyma, abdominal aorta, psoas muscle was measured. The estimated mean CNR (contrast-to-noise ratios), FOM (figure of merit), DLP (dose length product) and ED (effective dose) were compared between protocol A and B. Moreover, two radiologists assessed the visual quality of the CT images.
The mean DLP and ED in the protocol B was about 50% lower than that in the protocol A (p < 0.01). The mean CT value of the portal vein and abdominal aorta in the protocol B were significantly higher than that in the protocol A (p < 0.01). All of the FOM in the protocol B was significantly higher than that in the protocol A (p < 0.01). However, there was no significant difference in the mean CNR and visual quality between protocol A and B.
Performance of abdominopelvic CT using a low tube voltage plus reduced CM dose (80-kVp, 60% CM) achieved reduction of the radiation dose without impairing image quality in relatively light weight group.
CLINICAL RELEVANCE/APPLICATION: In abdominopelvic CT, protocol of low tube voltage (80-kVp) plus iodine dose reduction (60%) is able to provide the same quality of traditional protocols, also able to reducing radiation exposure (50%).
本研究旨在评估采用低管电压加低剂量对比剂（CM）方案（80 kVp，60% CM）的腹盆腔晚期计算机断层扫描（CT）图像质量。在同一患者中与传统方案（120 kVp，100% CM）进行比较。
本研究纳入22例患者{体重36至77 kg（平均：55.5 kg）}，这些患者有肾功能不全，且在18个月前有过无肾功能不全时进行传统CT检查的经历。测量门静脉、肝实质、腹主动脉、腰大肌的CT值。比较方案A和方案B之间的估计平均对比噪声比（CNR）、品质因数（FOM）、剂量长度乘积（DLP）和有效剂量（ED）。此外，两名放射科医生评估CT图像的视觉质量。
方案B的平均DLP和ED比方案A低约50%（p < 0.01）。方案B中门静脉和腹主动脉的平均CT值显著高于方案A（p < 0.01）。方案B的所有FOM均显著高于方案A（p < 0.01）。然而，方案A和方案B之间的平均CNR和视觉质量没有显著差异。
在相对体重较轻的人群中，采用低管电压加降低CM剂量（80 kVp，60% CM）进行腹盆腔CT检查，在不损害图像质量的情况下实现了辐射剂量的降低。
临床相关性/应用：在腹盆腔CT中，低管电压（80 kVp）加碘剂量减少（60%）的方案能够提供与传统方案相同的质量，同时能够减少50%的辐射暴露。
