ObjectivesTo investigate the influence of the abduction angle of the upper extremities on the image quality of non-enhanced CT scan and clinical value of the patients who cannot lift with double upper limbs by vehicle accident.Methods60 patients with double upper limbs that could not lift by vehicle accidents were required to receive liver non-enhanced CT scan, the patients were divided into 3 groups according to the abduction angle (group A, B, C), 20 cases in each group, another 20 cases with standard pose as the control group (group D). The CT value and standard deviation of the liver region of interest, the erector and the background air were measured, and the contrast to noise ratio of liver images, image noise value were calculated, together with the assessment of image quality and statistic analysis.ResultsThe liver non-enhanced CT scan were completed successfully. The image quality of group D was significantly better than A, B, C (Z=–10.753, P<0.05;Z=–11.645, P<0.05;Z=–12.281, P<0.05), respectively. Group C was better than A and B (Z=–8.502, P<0.05;Z=–4.068, P<0.05), respectively. Group B was better than A (Z=–5.885, P<0.05). The CNR of the four groups of images increased gradually, group A (0.09±0.77), group B (1.56±0.83), group C (2.51±0.87), group D (2.59±0.97), respectively. There were significant differences between four groups (F=36.323, P<0.05). The image noise decreased systematically, group A (14.84±2.94), group B (13.04±1.59), group C (11.60±1.72), group D (10.44±1.13), respectively. There were significant differences between four groups (H=426.755, P<0.05).ConclusionOn the premise of safety inspection, with the enlargement of angle of the upper limbs of patients who cannot lift with double upper limbs by vehicle accidents, the image noise decreased and image quality is improved with the increase of signal noise ratio.
目的 探討常規注射速率下單倍劑量對比劑在頸部三維對比增強磁共振血管成像（3D-CEMRA）中的可行性及臨床應用價值。 方法 2011年8月－11月，連續納入30例臨床懷疑頸動脈或椎動脈狹窄并要求頸部磁共振血管成像檢查的患者，隨機分成A、B兩組（每組各15例）。使用西門子Magnetom Avanto 1.5 T磁共振成像儀及其配備的頸部線圈和頭部線圈進行CEMRA成像。A組使用雙倍劑量對比劑（0.2 mmol/kg），B組使用單倍劑量對比劑（0.1 mmol/kg）。用三維快速小角度激發序列進行頸部血管成像。由2位有豐富經驗的高年資醫生對兩組原始圖像的信噪比以及最大密度投影（MIP）圖像的質量進行評價，并對結果進行統計學分析和處理。 結果 A、B兩組的所頸動脈信噪比分別為189.95 ± 71.31、175.07 ± 68.61，差異無統計學意義（t=?0.566，P=0.576）；所得的MIP圖像質量均達到優良，差異無統計意義（χ2=0.180，P=0.671）。 結論 與雙倍劑量相比，單倍劑量對比劑獲得頸部血管的圖像清晰，能夠滿足臨床診斷要求。
ObjectiveTo explore the clinical value of low-dose contrast agnet in CT angiography (CTA) for head and neck by SOMATOM Definition Flash CT.MethodsSixty consecutive patients with head and neck vessel diseases examined by CTA in the head and neck were chosen from West China Hospital of Sichuan University from March to July 2015, and then were randomly divided into two groups (the experimental group: n=30, 30 mL contrast medium; the control group: n=30, 50 mL contrast medium). Imaging post processing techniques included curved plannar reconstruction, volume rendering, and maximal intensity projection. CT values of the different level of carotid arteries (aortic arch, carotid bifuracation, and M1 segment of middle cerebral artery) were measured. The artifact of the remaining contract in the jugular vein and overall quality of the image were observed by two senior doctors using double blind method.ResultsAll the patients in the two groups completed CTA for head and neck successfully. The image qualities of the two groups satisfid clinical diagnostic requirements, and there was no difference in the image qualities between the two groups (P>0.05). The evaluation of venous pollution in the experimental group was lighter than that in the control group (P<0.05). The CT values of aortic arch, carotid bifuracation, and M1 segment of middle cerebral artery in the experimental group [(341.3±89.5), (391.0±103.7), (305.0±62.0) HU] were slightly lower than those in the control group [(437.3±83.7), (532.5±113.3), (396.6±93.1) HU], which were statistically significant (P<0.05).ConclusionLow-dose contrast in CTA for head and neck by SOMATOM Definition Flash CT can satisfy the clinical diagnostic requirements, and reduce the dose of contrast agent and venous pollution, with a good clinical value.
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.