摘要目的:探讨宽探测器多层螺旋CT(MDCT)靶扫描技术在胰腺癌术前评估中的应用价值。方法:回顾性分析2019年9月至2019年10月间海军军医大学第一附属医院22例行胰腺动脉CT增强扫描检查且经病理确诊的胰腺癌患者的临床资料。采用国际标准体模CATPHON 500进行CT体模实验，分别改变扫描辐射剂量、扫描模式以及扫描视野等，对获得图像的空间分辨率与密度分辨率进行对比分析。将实验获得的靶扫描技术参数应用于22例胰腺癌患者MDCT增强扫描的动脉晚期，采用高管电流、容积扫描模式及小扫描视野扫描，测量各时相胰腺癌组织与正常胰腺组织的衰减值(CT值)及噪声值(SD值)，计算两种组织的衰减差与对比信噪比(CNR)，评估不同时相两种组织的对比度差异，测量腹腔干、肾动静脉、肠系膜上动静脉、脾静脉、门静脉的CT值，评价肿瘤组织与胰周重要血管的显示情况。结果:在体模实验中，同等辐射剂量条件下，容积扫描模式的图像密度分辨率优于螺旋扫描模式(5 mGy时1%@4 mm比1%@9 mm；25 mGy时1%@2 mm比1%@6 mm)。胰腺肿瘤与胰腺组织对比，胰腺组织表现为强化过程先升高后下降，而胰腺肿瘤组织为轻度强化过程，胰腺组织与肿瘤组织的衰减差及CNR也是呈先增加后减少的过程，在动脉晚期达到最大值[(91.96±29.29)HU、8.60±5.71]，各时相之间的差异均有统计学意义( F值分别为47.20、19.80， P值均<0.05)。评估血管变异及侵犯情况显示，动脉晚期靶扫描图像上可以得到较好的动脉期图像，同时兼顾脾静脉、肠系膜静脉及门静脉的显示。 结论:采用宽探测器MDCT靶扫描技术可提高图像空间分辨率与密度分辨率，显著提高肿瘤组织与胰周组织及血管的对比度，为胰腺癌的术前评估提供更准确的肿瘤分期及可切除性评价信息。

abstractsObjective:To explore the application value of wide detector multi-slice spiral CT target scanning technique in the preoperative evaluation of pancreatic cancer.Methods:The clinical data of 22 patients with pancreatic cancer who underwent pancreatic arterial contrast enhanced CT scanning and were diagnosed by pathology in the First Affiliated Hospital of Naval Medical University from September 2019 to October 2019 were analyzed retrospectively. The CT phantom experiment was carried out on the international standard phantom CATPHON500. By changing the scanning radiation dose, scanning mode and scanning field of view, the spatial resolution and density resolution of the image were compared and analyzed. The target scan technical parameters obtained from the experiment were applied to the late arterial phase of MDCT enhanced scan in 22 patients with pancreatic cancer. Executive current, volume scanning mode and small scanning field were used for scanning. The attenuation value (CT value) and noise value (SD value) of pancreatic cancer tissue and normal pancreatic tissue were measured at different phases, the attenuation difference and contrast signal-to-noise ratio (CNR) of the two tissues were calculated, the contrast difference between the two tissues was evaluated, and the CT values of celiac trunk, renal artery and vein, superior mesenteric artery and vein, splenic vein and portal vein were measured, and the display of tumor tissue and peripancreatic important vessels was evaluated.Results:In the phantom experiment, under the condition of the same radiation dose, the image quality of the volume scan mode was better than that of the spiral scan mode (1%@4 mm versus 1%@9 mm at 5 mGy and 1%@2 mm versus 1%@6 mm at 25 mGy). In comparison between pancreatic tumor and pancreatic tissue, the enhancement process of pancreatic tumor tissue was increased at first and then decreased, while that of pancreatic tumor tissue was slightly enhanced. The attenuation difference between pancreatic tissue and tumor tissue and CNR also increased at first and then decreased, reaching the maximum at the late arterial stage [(91.96±29.29)HU, 8.60±5.71]. The differences between each phase were statistically significant ( F values were 47.20 and 19.80 respectively, all P values <0.05). The evaluation of vascular variation and invasion showed that a better arterial phase image could be obtained on the late arterial target scan images, while taking into account the display of splenic vein, mesenteric vein and portal vein. Conclusions:The wide detector MDCT target scanning technique can improve the spatial resolution and density resolution of the image, greatly improve the contrast between tumor tissue and peripancreatic tissue and blood vessels, and provide more accurate tumor staging and resectability evaluation information for preoperative evaluation of pancreatic cancer.