目的 探讨双源CT腰椎检查中低剂量扫描方法及其临床应用价值。 方法 将2011年8月－2012年5月行双源CT腰椎检查的714例患者随机分为7组。均采用管电压120 kV，分别依次采用常规参考管电流量250 mAs和低管电流量240、230、220、210、200、190 mAs，且均采用CARE DOSE技术采集数据。扫描参数：准直器64 mm×0.6 mm，重建层厚0.75 mm，重建间隔0.7 mm，FOV 180～200 mm。采集图像后，测量腰3椎体的CT值及同层面的脊髓的CT值、背脊肌的CT值及噪声；腰5椎体的CT值及同层面的脊髓的CT值、背脊肌的CT值及噪声，并计算腰3、腰5椎体及相应层面脊髓的信噪比(SNR)和其相对于背脊肌的对比噪声比（CNR）。应用统计学软件对不同管电流下的CNR、SNR、盲法评分的数值以及射线剂量指数（CTDI）、剂量长度乘积（DLP）、有效剂量（ED）进行分析。 结果 第1组和第2组比较，图像的背脊肌SD值；腰3、腰5椎体和脊髓的SNR值进行比较，差异无统计学意义（P＞0.05）。第1组与第3、4、5、6、7组比较，腰3、腰5低管电流量各组间图像的背脊肌SD值；腰3、腰5椎体和脊髓的SNR值与常规管电流量组间比较差异均有统计学意义（P＜0.05）。腰3和腰5各组图像的椎体-背脊肌和脊髓-背脊肌CNR值分别行单因素方差分析，结果差异均无统计学意义（P＞0.05）。 结论 双源CT腰椎检查时，通过阶段性逐步降低管电流量的方法，使诊断医生逐渐适应低剂量图像质量，从而实现现有设备的低剂量扫描的方法是可行的。对于体质量指数（BMI）≤25 kg/m2的患者，可以采用190 mAs的参考管电流量进行腰椎扫描，不仅降低了患者接受的辐射剂量，同时也能获得满足临床诊断的合格图像，并且保护患者和减小设备损耗。
目的 探讨双源CT低剂量扫描技术在胸部普通检查中的应用价值。 方法 将2011年8月－2012年12月收治的875例患者依次分为7组，分别采用常规管电流量110 mAs和低管电流量105、100、95、90、85、80 mAs测量，计算并评估7组患者纵隔窗图像的胸骨前空气CT值标准差（SD空气）、肺动脉分叉平面肺动脉信噪比、降主动脉信噪比、肺动脉-竖脊肌对比噪声比、降主动脉-竖脊肌对比噪声比；纵隔窗图像和肺窗图像主观质量评分以及射线剂量指标：CT剂量指数（CTDI）、剂量长度乘积（DLP）、有效剂量（ED）。 结果 7组患者纵隔窗图像肺动脉信噪比、降主动脉信噪比、图像主观质量评分和射线剂量CTDI、DLP、ED之间差异均有统计学意义（P＜0.05）；肺动脉-竖脊肌对比噪声比、降主动脉-竖脊肌对比噪声比之间差异无统计学意义（P＞0.05）；其中第7组图像信噪比、射线剂量和主观质量评分均为最低，部分图像肩背部出现横条状伪影，影响肺尖部病变的显示，难以提供足够的诊断信息。 结论 胸部普通CT检查，通过阶段性降低管电流量使诊断医生逐渐适应低剂量图像质量，从而普及现有设备的低剂量扫描的方法是可行的。双源CT采用85 mAs的参考管电流量，既能获得满足临床诊断的合格图像，又能明显降低患者群体接受的辐射剂量。
Objective To discuss the application of dual-source computed tomography （CT） low dose technology in the upper abdomen enhanced inspection. Methods Six hundred consecutive patients from July 2011 to February 2012 in this hospital were orderly divided into ordinal tube current （210 mAs） group and low dose tube current group （200 mAs，190 mAs，180 mAs，170 mAs，and 165 mAs）. The standard deviation （SD） of subcutaneous fat，signal to noise ratio （SNR） of liver and pancreas， contrast to noise ratio （CNR） of liver-erector spinae and pancreas-erector spinae，score of subjective diagnosis and the indexes of radiation dose，including CT dose index （CTDI），dose length product （DLP），effective dose （ED） were measured，calculated，and assessed respectively on CT images of arterial phase and portal phase from each group. Results The SD of subcutaneous fat， SNRs of liver and pancreas，score of subjective diagnosis，and the CTDI，DLP，ED of CT images in arterial phase and portal phase were significantly different from each other （P＜0.05），while CNRs of liver-erector spinae and pancreas-erector spinae were not statistically significant （P＞0.05）. The SNR，radiation dose，and score of subjective diagnosis of the 165 mAs tube current group were the lowest among all the groups，but the images of the 165 mAs tube current group could not fulfill the need of diagnosis. Conclusions It is really feasible that the method of decreasing tube current gradually in the upper abdomen enhanced CT inspection could ensure that the radiologists could adapt the low dose image bit by bit，and this methods could be popularized to all kinds of CT facilities we own currently. The images with 170 mAs as tube current in the upper abdomen enhanced inspection of dual-source CT could fulfill the need of diagnosis，and the radiation dose of patients is apparently lower than that the conventional scan．
ObjectiveTo discuss the characteristics of coronary artery disease in patients with type 2 diabetes using coronary angiography of Dual Source CT. MethodsWe collected the clinical data of patients who underwent coronary angiography of Dual Source CT between December 2010 and November 2012 in Sichuan Provincial People's Hospital and Sichuan Orthopedic Hospital. A total of 302 patients (74 with type 2 diabetes, and 228 with no diabetes) were examined with CT coronary angiography. All images were comprehensively assessed. Types of plaques and luminal narrowing were evaluated. ResultsPatients with type 2 diabetes had more plaques (P<0.05), especially mixed plaques and non-calcified plaques, than non-diabetic patients (P<0.05). The proportions of calcified plaque, mixed plaques, non-calcified plaque in patients with type 2 diabetes were 29.1%, 41.1%, 29.8%, respectively. The proportions of calcified plaque, mixed plaques, non-calcified plaque in patients with nondiabetic patients were 39.7%, 36.0%, 24.3%, respectively. The difference of the composition between diabetes and nondiabetic was significant (P<0.05). There were more mild, moderate and severe narrowing in type 2 diabetic patients than those in non-diabetic patients (P<0.05). ConclusionCoronary angiography of CT depicts a high plaque burden in patients with type 2 diabetes mellitus (mixed plaque is the most common type), which may cause stenosis easily.
ObjectiveTo evaluate the value of 120 kV portal venous phase images combined with iodine maps created from dual-source dual-energy CT (DECT) for the diagnosis of pancreatic necrosis in the early stage of acute pancreatitis. MethodsThis prospective study enrolled 17 patients who underwent abdominal dual-source DECT within 72 hours from the onset of acute pancreatitis. All patients had received treatment in West China Hospital from May 2014 to August 2014. Comparison of the diagnostic value of 120 kV portal venous phase images alone and 120 kV portal venous phase images combined with iodine maps created from dual-source DECT was performed. ResultsSix of the 17 patients were found the presence of pancreatic necrosis (4 patients without obvious necrosis in the early stage developed to pancreatic necrosis, and 2 patients with the presence of necrosis in the early stage improved). The sensitivity, specificity, and accuracy of 120 kV portal venous phase images for the diagnosis of pancreatic necrosis were 50.0% (3/6), 100% (11/11), and 82.4% (14/17), respectively, and it had a good diagnostic value (AUC=0.856, P=0.018). The sensitivity, specificity, and accuracy of 120 kV portal venous phase images combined with iodine maps created from dual-source DECT for predicting pancreatic necrosis were 100% (6/6), 90.9% (10/11), and 94.1% (16/17), respectively, and this method had good value too (AUC=0.977, P=0.002), which higher than that of 120 kV portal venous phase images (P=0.002). ConclusionsThe 120 kV portal venous phase images combined with iodine maps created from dual-source DECT is helpful to improve subjective judgment in the diagnosis of pancreatic necrosis in the early stage of acute pancreatitis. It also contributes to the display of hypo-perfusion area of the pancreatic parenchyma, and has higher diagnostic value.
ObjectiveTo evaluate the manifestations and diagnostic value of pediatric acute appendicitis with dual-source CT (DSCT). MethodsRetrospectively analysis of CT features of 97cases of surgically and pathologically confirmed pediatric acute appendicitis in our hospital were performed. ResultsAmong 97 patients, 7 cases were diagnosed acute simple appendicitis, 20 cases with acute suppurative appendicitis, perforated and gangrenous appendicitis in 58 cases, and appendiceal abscess in 12 cases. According to the location of appendix confirmed by CT, 28 cases of appendicitis could not be clearly manifested, the cohort of the remaining 69 cases were composed of 20 cases (29.0%) with appendix located in pelvic, 15 cases (21.7%) with appendix in front of ileum, 11 cases (15.9%) with appendix behind ileum, 12 cases (17.4%) with appendix behind cecum, 3 cases (4.3%) with appendix below cecum, 1 case (1.5%) with appendix outside of cecum, and 7 cases (10.2%) with appendix located in other positions. CT and three-dimensional reconstruction findings were as followed:swelling enlarged appendix, appendicoliths, periappendiceal fat fuzzy, peritoneal thickening, ileocecal thickening, mesenteric lymphadenopathy, periappendiceal mass, and abdominal or pelvic fluid. The diagnostic rate of acute simple appendicitis with CT was 85.7% (6/7), acute suppurative appendicitis was 80.0% (16/20), perforated and gangrenous appendicitis was 100% (58/58), appendiceal abscess was also 100% (12/12), the overall diagnostic yield was 94.8% (92/97). ConclusionDSCT can well demonstrate the anatomical location of appendix and pathological changes of surrounding tissues, and has higher diagnostic accuracy, provide powerful information for surgeons.