【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.
Scoliosis is a complex three-dimensional spinal deformity, characterized by lateral curvature and vertebral rotation. Radiology plays important roles in the assessments of lateral curvature and vertebral rotation of the patients with scoliosis, as well as the prediction of progression and treatment outcomes of scoliosis. The reliable and validity of radiological assessments have been proved in the coronal, transverse, and sagittal planes of scoliotic spine. With the application of the stereoradiography, three dimensional nature of the scoliosis has been disclosed. This review aims to summarize the radiological methods for the assessments of scoliotic spine, the reliability and validity of each method, as well as the stereoradiography, providing the basis for accurate diagnosis and assessments for the patients with scoliosis.
Objective To explore feasibility and clinical value of low dose computed tomography perfusion imaging (CTPI) in quantitative assessing proximal gastric cancer. Methods A total of 34 patients diagnosed with proximal gastric cancer (a proximal gastric cancer group) were enrolled prospectively in this study. The 25 normal parts of gastric fundus of the included patients constituted a control group. All the patients underwent the low dose CTPI before surgery. The total effective radiation dose was recorded, and a specific post-processing software was used to automatically generate the perfusion parameters values, including the time to peak (TTP), blood flow (BF), blood volume (BV), mean transmit time (MTT), and permeability (PMB). The perfusion parameters in the different histopathologic types and stages of the patients were compared. Receiver operating characteristic (ROC) curves were generated to compare their diagnosis performances. Results The histopathologic findings verified that there were 11 patients with T1+T2 stage and 23 patients with T3+T4 stage; 8 patients with signet ring cell carcinoma and 26 patients with adenocarcinoma; and 17 patients with lymphatic metastasis and 17 patients without lymphatic metastasis. ① Compared with the control group, the BF, BV, and PMB values were significantly higher and the MTT and TTP values were significantly lower in the proximal gastric cancer group. The area under the ROC curve (AUC) values of the BF, BV, PMB, MTT, and TTP in the diagnosing proximal gastric cancer was 0.955, 0.807, 0.987, 0.654, and 0.649 respectively. The BF and PMB represented the best diagnostic performances, and the BV was secondary in the ROC curve results. ② The BF value was significantly lower and the PMB value was significantly higher in the patients with signet ring cell carcinoma as compared with the patients with adenocarcinoma. However, the BV, MTT, and TTP values had no significant differences in both them. And the BF (AUC=0.986) had a better ability than the PMB (AUC=0.856) in the discriminating the histopathological type (P=0.047). ③ The PMB value in the patients with pathological stage T3 and T4 was significantly higher than that of the patients with pathological stage T1 and T2 (P=0.004), but the BF, BV, MTT, and TTP values had no differences in both them. The diagnosis value of the PMB in the discriminating the pathological stage was good with an AUC value of 0.814. ④ None of the parameters had significant difference between the patients with and without lymphatic metastasis (P>0.05). ⑤ The total effective radiation dose of each scan was 8.58 mSv, which was lower than that of the standard radiation dose of CTPI. ⑥ The rates of lymphatic metastasis and high T staging were not related to the histopathological type of the proximal gastric cancer (P>0.05). Conclusion Low dose CTPI used in this study could effectively reduce radiation dose, could quantitatively evaluate angiogenesis in proximal gastric cancer, and has a certain clinical value in identifying of histopathological type and evaluating of pathological stage.
ObjectiveTo explore the impact of different monochromatic reconstruction on image quality of early lesions of coronavirus disease 2019 (COVID-19).MethodsThe chest spectral CT images of 11 patients confirmed as COVID-19 in West China Hospital of Sichuan University between January and February 2020 were retrospectively analyzed. A total of 34 inflammatory lesions were found in the 11 cases. Seven groups of images were reconstructed from the raw data for each patient, including the conventional polychromatic image and different monochromatic images of 40-140 keV (with intervals of 20 keV). CT and standard deviation (SD) values of all lesions were measured to calculate the signal-noise ratio (SNR) and contrast-noise ratio (CNR). The image quality was subjectively scored by two radiologists, and the differences in image quality among different monochromatic groups and the polychromatic group were compared.ResultsWith the increase of X-ray energy, the CT values and SD values of reconstructed images in monochromatic groups gradually decreased, and the SNRs and CNRs gradually increased, and the differences between adjacent two groups were all statistically significant (P<0.001). In the range of 80-140 keV, the SD values of different monochromatic groups were lower than that of the polychromatic group, and the SNRs and CNRs were higher than those of the polychromatic group, and the pairwise comparison results showed statistically significant differences (P<0.001). The 120 keV-reconstructed image had the highest subjective score, and the difference from that of the polychromatic image was statistically significant (P<0.05).ConclusionsDifferent monochromatic reconstruction of spectral CT can significantly reduce the image noise in early COVID-19 lesions, and improve the image quality. Combining subjective and objective evaluation of images, the 120 keV-reconstructed monochromatic image shows the best early lesions of COVID-19 and is of great significance for early clinical screening.
ObjectiveTo summarize the application of spectral CT in the diagnosis of common, frequently occurring, and acute severe gastrointestinal diseases. MethodThe literature and guidelines on spectral CT were reviewed, and the main conclusions and opinions were summarized. ResultsThe spectral CT could obtain a variety of tissue parameters through a single scan. Through post-processing, multiple sequence images could be obtained, including virtual single-level images, virtual unenhanced images, iodine density images, effective atomic number images, etc. And multiple quantitative indicators could also be obtained, including iodine concentration, standardized iodine concentration, spectral curve, effective atomic number, etc. It could improve the signal-to-noise ratio of the image, reduce artifacts, increase iodine contrast, and decrease iodine load, then could improve the detection rate of active gastrointestinal bleeding and ischemic bowel diseases, improve the assessment accuracy of inflammatory activity of Crohn disease, and help to identify benign and malignant gastrointestinal tumors, determine the histological origin and evaluate the therapeutic effect. ConclusionFrom the conclusion summarized in this review, spectral CT images and quantitative indicators could provide more valuable information for detection, diagnosis, and prognosis of gastrointestinal diseases.