目的：探讨双源CT小肠成像双能量虚拟平扫技术在炎性肠病（IBD)诊断中应用的可行性。方法：回顾性分析37例临床确诊IBD患者的CT资料（31例克罗恩病、6例溃疡性结肠炎），所有患者均行双源CT小肠成像检查，扫描包括常规平扫及动脉期、门静脉期双能量扫描（100 kVp/210 mAs和Sn140 kVp/162 mAs）。利用Liver VNC软件处理得到动脉期、门静脉期2组虚拟平扫数据，并与常规平扫对比，比较三者在图像质量、辐射剂量及病变肠段检出上的差异。结果：与常规平扫图像比较，动脉期及静脉期虚拟平扫图像上所有炎症肠段均能显示，且病变肠段范围无明显差异。两期虚拟平扫图像完全能满足诊断要求；观察到肠壁厚度、肠壁水肿、肠周渗出、肠管形态及引流区淋巴结大小等无明显差异。虚拟平扫CT值在病变肠壁、引流区淋巴结等略低于常规平扫，但差异无统计学意义。虚拟平扫图像噪声低于真实平扫（P<0.05），信噪比高于常规平扫图像（P<0.05）；两位医师对虚拟平扫图像质量评分均≥3分，双期虚拟平扫图像评分差异无统计学意义。常规平扫、双能量动脉期、双能量静脉期扫描的剂量长度乘积（DLP）及有效辐射剂量（ED）差异无统计学意义（F=0.993，P=0.374）；与常规三期扫描相比，采用两期双能量扫描辐射剂量减少约32.97%。结论：对于IBD，双源CT小肠造影双能量虚拟平扫可以在降低辐射剂量、减少辐射损伤的同时满足临床诊断的要求，可作为IBD诊断的常用方法。
Abstract
Objective: To assess the clinical feasibility of dual-source CT enterography using dual-energy virtual non-contrast(VNCT) imaging in diagnosis of inflammatory bowel diseases. Materials and Methods: The dual-energy dual-source CT enterography data from a cohort of 37 inflammatory bowel disease patients(31 Crohn’s disease and 6 ulcerative colitis), who were confirmed by clinical settings, were analyzed retrospectively. All the patients underwent abdominal conventional non-enhanced CT scan(CNCT) as well as arterial and venous phase dual-energy enhanced scan(100 kVp/210 mAs and Sn140 kVp/162 mAs). VNCT images of arterial and venous phase were obtained using the dual-energy software. The differences of image quality, radiation dose and diagnostic coincidence rate between the true non-contrast scan and VNC images were compared. Results: Compared with CNCT images, all the inflammatory bowel segments were detected accurately by VNCT images, and there was no significant difference of size and extent of lesions between the CNCT and VNCT. All the VNCT images met the requirement of diagnosis, and the differences of intestinal wall thickness, intestinal wall edema or effusion, intestinal morphology and lymph node size were no significant. The noise level of images obtained from VNC was lower than that of the real non-contrast scan(P<0.05), with higher SNR(P<0.05). There was no significant difference of image scoring among the three groups(P>0.05). There was no statistic difference of the radiation dose of conventional non-enhanced CT, arterial and venous phase CECT. The radiation dose of two-phase dual-energy scan was 32.97% lower than that of the conventional threephase scans. Conclusion: For inflammatory bowel diseases, the virtual non-contrast images obtained from the dual-energy CT scan can effectively reduce the radiation dose, decrease radiation injury, and meet the needs of clinical diagnosis.
关键词
炎性肠疾病；体层摄影术 /
螺旋计算机
Key words
Inflammatory bowel diseases /
Tomography, spiral computed
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