输精管盆腔段及其周围结构的多层螺旋CT多期图像融合显示及影响因素分析

目的 探讨多层螺旋CT(MSCT)多期图像融合显示输精管盆腔段及其周围结构的可行性,并对输精管盆腔段显示的影响因素进行分析。方法 前瞻性研究。以连续入组方式纳入2018年1月—2018年4月中山大学附属第一医院有多期MSCT盆腔扫描资料、年龄20~50岁的男性住院患者174例。对患者盆腔MSCT平扫期、静脉期及排泄期图像分别行容积重组,获得输精管盆腔段、髂血管、输尿管及膀胱图像,再进行图像融合。对融合图像进行评定:以双侧输精管盆腔段、输尿管及髂血管清晰显示,且无邻近器官干扰为合格图像,其余为不合格图像。归纳影响图像显示的因素,并进行统计学分析。结果 获得合格图像72例(41.4%),不合格图像102例(58.6%)。影响图像显示的因素有:患者体质量指数(BMI)、盆腔小肠积聚、邻近器官(膀胱和/或直肠)过度充盈、年龄。合格图像患者的BMI为17.19~31.49(24.49±2.93)kg/m²,不合格图像为14.17~27.95(20.59±3.02)kg/m²,差异有统计学意义(t=8.493, P＜0.01);BMI≥22.55 kg/m² 为获得合格图像的界值,敏感度77.8%,特异度73.6%,受试者操作特征曲线下面积0.821。盆腔小肠积聚(72例)直接影响输精管盆腔段的显示,无法获得合格图像。无盆腔小肠积聚的102例患者中,无邻近器官过度充盈者与有邻近器官过度充盈者获得合格图像分别为84.6%(44/52)和56.0%(28/50),差异有统计学意义(χ²=10.054, P＜0.01)。按年龄段统计,合格图像比例随年龄增大而提高:20~30岁26.7%(8/30), 31~40岁39.6%(19/48),41~50岁46.9%(45/96),但不同年龄段的合格图像比例差异无统计学意义(χ²=3.936, P＞0.05)。结论 MSCT多期图像融合可以直观、立体地显示输精管及其周围结构,尤其适用于BMI≥22.55 kg/m²的人群,在充分做好检查前准备的基础上,可获得合格的图像。

Analysis of pelvic vas deferens and its adjacent structure display and influencing factors on multiple-phase CT fusion imaging

Objective To explore the feasibility of multiple-phase CT (MSCT)volume-rendered reconstruction and image fusion for displaying pelvic vas deferens and its adjacent structure, and analyze the influencing factors of displaying pelvic vas deferens.Methods The prospective study was conducted. A total of 174 male patients aged from 20 to 50 years old underwent multiple-phase abdominopelvic CT scan from January 2018 to April 2018 in the Affiliated Zhongshan Traditional Chinese Medicine Hospital of Guangzhou University of Chinese Medicine were prospectively included. Volume-rendered reconstruction and image fusion were made in all patients: pelvic section of vas deferens based on nonenhanced phase, iliac artery and iliac vein based on venous phase, ureter and bladder on delayed phase. The fusion images were evaluated: bilateral pelvic vas deferens, ureter, iliac vessels were clearly displayed, and no adjacent organs interference were considered as qualified images. The rest were unqualified images. then factors influencing image display were analyzed, and statistical analysis was performed.Results Fusion images from 72/182 (41.4%) patients were considered as qualified, on which bilateral vas deferens were clearly displayed and clinical analysis could be made. Fusion images from the remaining 102 (58.6%) were excluded. Factors affecting image displaying included body mass index (BMI), accumulation of small bowel in pelvic, overfilling of adjacent organs (bladder and/or rectum) as well as patients' age. The BMI range of the qualified images was 17.19-31.49(24.49±2.93)kg/m², and the BMI range of the unqualified images was 14.17-27.95(20.59±3.02)kg/m², and the difference was statistically significant (t=8.493, P＜0.01). BMI≥22.55 kg/m² was considered as the cut-off value for qualified images, with a sensitivity and specificity of 77.8%, and 73.6%, respectively(ROC curve 0.821, P＜0.01). Images showing small bowel accumulation were considered disqualified. Patients without bladder and/or rectum overfilling had a higher percentage of qualified images 84.6%(44/52)vs 56.0%(28/50)] and the statistical difference was significant (χ²=10.054, P＜0.01). Patients were divided into 3 groups according to age, although the proportion of qualified images increased with aging:26.7% (8/30) of 20-30 years old, 39.6% (19/48) of 31-40 years old and 46.9% (45/96) of 41-50 years old, no statistical significance was found(χ²=3.936, P＞0.05).Conclusions The influencing factors of image displaying include BMI, accumulation of small bowel in pelvic, overfilling of adjacent organs as well as patients' age. For patients with BMI of 22.55 kg/m² or above, qualified images displaying pelvic vas deferens and adjacent structure by MSCT volume-rendered reconstruction and image fusion can be made through a proper preparation such as intestinal preparation and moderate bladder filling before CT scan.