【摘要】 目的 评价64层螺旋CT低剂量冠状动脉血管成像的价值。 方法 2009年1-6月157例患者随机分为3组，常规剂量组（A组）管电流量采用1 000 mAs，两个低剂量组（B、C组）分别采用800、600 mAs。对3组的图像质量、噪声、CT剂量指数（CTDI）、剂量长度乘积（DLP）和有效剂量（ED）进行评估。 结果 A、B、C组图像噪声分别为20.50±3.23、23.02±3.05和26.28±2.58，组间差异均无统计学意义（Pgt;0.05）；A、B、C组的CTDI分别为（58.7±0.23）、（46.98±2.27）、（35.28±3.56） mGy，DLP分别为（1 050.88±89.63）、（846.21±57.86）、（641.13±32.15） mGy?cm，ED分别为（14.78±2.56）、（11.85±1.87）、（8.98±1.15） mSv，B、C组的CTDI、DLP、ED均明显低于常规剂量A组（Plt;0.05），C组的CTDI、DLP、ED均为3组中最低值。 结论 64层螺旋CT冠状动脉血管检查，采用600 mAs管电流量获得的冠脉图像既可满足诊断需要，又可使患者接受的辐射剂量降低。【Abstract】 Objective To evaluate the best tube current for low-dose radiation CT in coronary artery imaging by 64-slices multi-detector CT. Methods From January to June 2009, a total of 157 consecutive patients were randomly divided into 3 groups: group A (conventional group): 1 000 mAs; group B: 800 mAs; group C: 600 mAs. The image quality, noise, CT dose index (CTDI), dose length product (DLP) and effective dose (ED) in each group were measured and compared respectively. Results The image noise scores in group A, B, and C were (20.50±3.23), (23.02±3.05) and (26.28±2.58), respectively. There was no statistically significant difference among the three groups in the two indexes (Pgt;0.05). The CTDI in group A, B and C were (58.7±0.23), (46.98±2.27), and (35.28±3.56) mGy, respectively; the DLP in each were (1 050.88±89.63), (846.21±57.86), and (641.13±32.15) mGy?cm, respectively; the Ed were (14.78±2.56), (11.85±1.87), and (8.98±1.15) mSv, respectively. All of the differences among the three groups in CTDI, DLP and ED were statistically significant (Plt;0.05). Conclusion The image with 600 mAs as tube current in the coronary artery imaging of 64-slices multi-detector CT could fulfill the need of the diagnosis, and the radiation dose is apparently lower than the conventional scan.
ObjectiveTo explore the influence of different concentrations of iodinated contrast agent on image quality of galactography. MethodsBetween June 2008 and October 2009, 50 non-pregnancy and non-lactation patients with mammary papilla discharge underwent breast galactography with digital mammography. All the patients' left breasts were in group L, and right breasts were in group R. The iohexol concentration of iopamidol injection was 370 mg/mL in group L and 300 mg/mL in group R. The image quality and the evaluation of average density of the two groups was analyzed and compared. ResultsThe image quality score of group L and R was 2.8±0.2 (P>0.05). The mean density of main duct of breast axial view in two groups was (4 020.25±96.26) and (3 984.75±117.67) HU, respectively; the mean density of the lateral oblique view was (4 067.13±24.69) and (3 971.25±167.32) HU, respectively; the mean density of the lateral view was (4 058.88±52.07) and (4 034.75±67.54) HU, respectively. There was no significant difference between the two groups (P>0.05). ConclusionNo obvious difference between the two concentrations of non-ionic iodinated contrast agents (300 and 370 mg/mL) in galactography diagnosis is found.
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.
Objective To summarize the recent application progress of dual-energy CT in pancreatic imaging. Methods The domestic and international published literatures related to the application of dual-energy CT in pancreatic imaging in recent years were collected and reviewed. Results Dual-energy CT could provide the morphological image and function information of tissues and organs simultaneously. At present, the clinical application of dual-energy CT in pancreatic imaging included low tube voltage technology, iodine overlay, virtual non-enhanced imaging, and monoenergetic imaging. Conclusion Dual-energy CT could contribute to detecting pancreatic lesions, reducing radiation dose, and improving image quality in pancreatic imaging.
【摘要】 目的 探讨多层螺旋CT低剂量扫描在小儿上尿路梗阻性疾病中的应用价值。 方法 2008年1月-2009年6月经临床手术证实尿路梗阻的患儿52例，按梗阻的原因分为结石组13例与非结石组39例。将非结石组患儿，按照年龄分为0~1岁（8例）、1~5岁（16例）和5~10岁（15例）3个组，均采用个性化的低剂量扫描方式。 结果 结石组与非结石组阳性诊断率均为100%。低剂量扫描患儿所接受的辐射剂量明显降低，CT扫描管电流不变，管电压降低1/3，CT检查的辐射剂量可降低约70%，且均可达到临床诊断要求。 结论 多层螺旋CT低剂量个性化扫描在小儿上尿路梗阻性疾病中诊断中具有明显优势。【Abstract】 Objective To evaluate low-dose multislice spiral CT for upper urinary tract obstruction in children. Methods From January 2008 to June 2009, 52 children with upper urinary tract obstruction were diagnosed via clinical surgeries. The patients were divided into two groups according to whether having renal calculus (13 patients) or not (39 patients). The patients in non-calculus group were divided into three sub-groups: aged 0-1 (eight patients), 1-5 (16 patients), and 5-10 (15 patients). Low dose multislice spiral CT with different doses was performed. Results The rate of positive predictive diagnosis was 100% in both calculus and non-calculus group. Low dose scan reduced the radiation dose of children. The fixed tube current and the decreased tube voltage (decreased 1/3) led to the decrease of the radiation dose (decreased 70%), which were feasible for diagnosis. Conclusion Low-dose multislice spiral CT was available for upper urinary tract obstruction in children.
ObjectiveTo discuss the value of dual-source CT Flash scanning in reducing the dose of radiation in 3D cardiac imaging. MethodWe collected 60 patients from March to August 2014 who should undergo cardiac 3D CT scanning before radiofrequency ablation. They were randomly divided into group A and B with 30 in each. Patients in group A underwent flash technology scanning, while those in group B accepted conventional retrospective electrocardiography-gated scanning. CARE Dose techniques were used to collect data. Scanning parameters were the same for both groups:collimation was 128×0.6 mm, reconstruction thickness was 0.75 mm, reconstruction interval was 0.7 mm, and field of view was 180-200 mm. After image acquisition, we measured the CT values and noise of left atrium and various branches of the pulmonary veins (upper left, lower left, upper right, and lower right). Statistical software was used for the two groups of images to analyze the carrier noise ratio (CNR), signal noise ratio (SNR), blinded scores, computed tomography dose index (CTDIvol), and dose-length product (DLP) of the left atrium and pulmonary vein. ResultsCNR and SNR of the left atrium and various pulmonary veins between the two groups had no significant differences (P>0.05) . Blinded scores between the two groups were not significantly different (P>0.05) . CTDIvol in group A and group B was respectively (2.92±0.38) and (20.15±12.09) mGy, with a significant difference (t=?7.803, P<0.001) . DLP of group A was (59.30±6.67) mGy·cm, significantly lower than that in group B [(334.43±216.71) mGy·cm] (t=?6.591, P<0.001) . Flash-efficient radiation dose was (0.83±0.94) mSv in group A, far below that in group B [(4.53±3.03) msv], and the difference was statistically significant (t=?6.684, P<0.001) . ConclusionsDual-source CT Flash technology applied in 3D cardiac scanning can reduce radiation dose as well as meet the needs of image diagnosis.
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．