Objective:To explore the value of synthetic MRI in quantitative monitoring of knee joint structural and cartilage changes of amateur marathon runners before and after the whole marathon.Methods:Totally 26 amateur marathon enthusiasts from Zhuhai City, Guangdong Province were recruited from October 2019 to January 2020. The right knee joints were scanned 1 week before the race and within 48 h after the race. The scanning sequence included the three-dimensional proton density weighted image with isotropic (3D-CUBE-PD) sequence and synthetic MRI sequence. The conventional contrast weighted images T 1WI, T 2WI, proton density (PD) weighted imaging, short-T 1 inversion recovery (STIR) and T 1, T 2, PD mapping were obtained by the latter scans. The 3D-CUBE-PD sequence was used as a reference to evaluate the detection of knee joint lesions. The knee articular cartilage was divided into 8 subregions: central medial femoral condyle (CMFC), posterior medial femoral condyle (PMFC), central lateral femoral condyle (CLFC), posterior lateral femoral condyle (PLFC), medial tibia plateau (MTP), lateral tibia plateau (LTP), patella and trochlear. Based on the synthetic MRI quantitative mapping, the T 1, T 2 and PD values of each cartilage subregion were measured independently by 2 radiologists. The ICC was used to evaluate the consistency of the measurement between observers. The T 1, T 2 and PD values of knee cartilage before and after marathon exercise were compared by Wilcoxon signed rank test. Results:The 2 radiologists had good consistency in the measurement of T 1, T 2 and PD values of knee articular cartilage with the ICC values of 0.912, 0.933 and 0.954, respectively. The synthetic MRI quantitative mapping sequence can detect all cartilage damage ( n=3) and joint effusion ( n=15), and 7 of 9 meniscus injuries were detected. The T 1, T 2 and PD values of the knee cartilage as a whole before the race were higher than those after race, and the differences were statistically significant (all P<0.05). The T 1 values were statistically significant except patellar cartilage and trochlear cartilage, and T 2 values were significantly different in the CMFC, LTP, MTP ( P<0.05). Conclusion:Synthetic MRI has a good display of knee joint structural lesions, and its quantitative parameters T 1, T 2 and PD can detect the changes of knee cartilage before and after marathon.

Objective To study the relationship of the superior vena cava (SVC) and the carina on CT and determine the tip position of peripherally inserted central catheter (PICC).Methods 100 consecutive patients who received contrast en hanced CT scan were retrospectively studied by measuring the distance between the carina and the cavoatrial junction (CAJ) in terms of absolute value and corresponding vertebral body unit (VBU).The distance between the carina and the upper end of the lower one-third of the SVC was also measured.Using the reference of lower one-third of the SVC as the optimal posi tion,the tips of PICC in another 100 patients were observed on both CT scout images and thin slice axial images.Results The distance between the CAJ and the carina was measured 48.5mm ± 6.7,which was corresponding to 2.1 ± 0.3 VBU.The upper end of lower one third of the SVC was measured 21.5mm ±5.9 below the carina,which was corresponding to 0.9 ±0.3 VBU.The accuracy of determining the PICC to be in the optimal position by using the range of 0.9-2.1 VBU below the ca rina as the reference of lower one third of the SVC was better than that of using the range of 21.5-48.5 mm below the carina as the reference (92％ vs.71％,P ＜ 0.05).Conclusion The range of 0.9-2.1 VBU below the carina is well corre sponding to the lower one third of the SVC which can be used as the reference for the PICC position.

目的 探讨“双低”血管成像技术-低千伏、低对比剂用量应用于临床头颈部血管成像的可行性.方法 采用35ml的低对比剂用量用于头颈部CT血管成像,将2 0例临床疑似头颈部血管疾病患者随机分为2组,实验组10例采用80KV进行头颈部血管成像扫描,对照组1 0例采用常规120KV,两组的对比剂用量均为35ml,注射速率为5ml/s,注射完毕后同等速率注入生理盐水40ml;均采用自动管电流调节技术(Caredose 4D),迭代算法(SAFIRE)重建,根据原始图像及最大密度投影像(MIP),比较不同千伏血管强化程度,不同KV下的辐射剂量、脑实质的密度及信号噪声比(SNR)、对比噪声比(CNR)、噪声等,并对其进行统计学分析.结果 实验组和对照组图像质量评分分别为5.833±0.100和5.856±0.133,P=0.694＞ 0.05;图像噪声分别为2.261±0.026和2.522±0.031 (P=0.000＜0.05),噪声明显增加;辐射剂量分别为412.4±49.2和101.8±11.6,P=0.000＜ 0.05,辐射剂量显著下降.结论 采用“双低”技术进行头颈部CT血管造影,所得图像能满足影像诊断,且大为减少辐射剂量和对比剂用量,可望用于头颈部CT血管成像筛查和治疗后复查,值得临床进一步深入研究和推广应用.

目的 CT引导下肺穿刺活检的辐射剂量研究。方法随机选取来我科做肺CT穿刺活检的患者50例,其中男性30例,女性20例,年龄37～82岁,中位年龄58.3岁;采用德国西门子公司生产Sensation 16层螺旋CT机;受检者卧于检查床上,根据肺部病灶的大小、部位,由介入科医生确定扫描体位,如仰卧、俯卧或侧卧,然后放置定位标记。先扫描一张定位相,再根据病灶的部位行病灶局部扫描,病灶扫描第一个序列为常规剂量,第二个序列起均为低剂量扫描。具体扫描参数为:常规剂量扫描管电压120 kV,管电流100 mAs;低剂量扫描管电压100 kV,管电流50mAs。球管旋转时间0.75 s/圈,准直器16×1.5 mm,螺距1.35,重建层厚2.0 mm,重建间隔1.0 mm,图像重建函数核肺窗B70S,very sharp,纵膈窗B30,medium smooth,Fov330 mm。扫描重建后的薄层图像传入3D重组,穿刺医生即时阅读、浏览,确定穿刺针进针的部位、方向、深度以及与病灶的三维关系。结果所有低剂量图像都能用于穿刺定位,噪声略高于常规扫描图像;低剂量扫描辐射剂量低,是常规法扫描的40.25%(平均值);本研究组共节省辐射剂量1 775.5 mGy。结论 CT引导下肺穿刺活检图像不需要很高的分辨率,低剂量扫描图像能够满足穿刺定位的要求。

Objective To evaluate the diagnostic value and application safety of multi-slice Spiral CT percutaneous needle biopsy of pulmonary occupying lesions.Methods 50 cases patients with benign or malignant lesion in the lung were performed 16 slice CT-guided percutaneous needle biopsy respectively.The samples were detected by cytological and pathological measures.CT scan was performed after biopsy to observe aeropleura and hemorrhage and to analyze operating time,accuracy of samples,and complication.Results Among 50 cases,48 cases were final diagnosis.38 were malignant and 10 were benign lesions.Frequency rate of complication was 4%.Conclusion More information was provided by multi-slice Spiral CT.Multi-slice spiral CT-guided percutaneous needle biopsy had higher successful rate and accurate rate,it should be the leading final diagnosis choice of occupying lesions.