螺旋CT增强延时及后处理技术在小儿先天性尿路梗阻性疾病的应用

目的：探讨螺旋CT增强延时及图像后处理技术在诊断小儿先天性尿路梗阻性疾病的临床应用价值。方法：108例经手术证实的小儿先天性泌尿系梗阻畸形患儿。术前1周行多层螺旋CT重建尿路成像（MSCTU）不同增强延时时间点低剂量扫描及图像后处理和超声检查，实质期及排泄期分别测量肾脏最大截面CT值；皮质期、实质期采用多平面重组（MPR），排泄期加做最大密度投影（MIP）、曲面重组（CPR）及表面重组（SSD）图像，并将MSCTU诊断结果与超声诊断结果进行比较。结果：重度肾盂输尿管连接部梗阻（UPJO）男孩左侧肾脏发病率为76．19％，明显高于其他泌尿系畸形；重复肾重复输尿管积水以女孩发病为多，发病率为84．00％。单纯肾输尿管远端梗阻患肾功能均较好；重度UPJO患肾分泌功能尚存在，排泄功能较差；重度肾发育不全和积水型重复肾，患肾功能最差，其次为反流性肾病的肾脏。MSCTU的术前诊断完全符合率为96．30％，超声的术前诊断完全符合率为60．04％。MPR方便快捷，适合于肾脏功能及结构观察；CPR，MIP，SSD适合集合系统形态轮廓整体观察、肾排泄功能评价、积水梗阻平面判定及疾病定性诊断。结论：掌握最佳的MSCTU增强延时时间，选择合理的低剂量扫描及图像后处理功能，能十分准确地诊断小儿先天性复杂泌尿系梗阻畸形疾病，MSCTU技术可作为泌尿系术前常规影像学一站式首选检查方法。

Application of delayed enhancement MSCTU scanning and image processing in congenital urinary obstruction lesions in children

Objective： To evaluate the value of delayed enhancement MSCTU scanning and image processing in the diagnosis of congenital urinary obstructive lesions in children. Methods： Delayed enhancement MSCTU scanning, image processing and ultrasonography were performed in 108 patients with congenital urinary obstruction lesions before operation, all cases were confirmed by operation. The cortical-phase images and the parenchymal-phase images were reconstructed with muhiplanar reconstruction（MPR）, the excretory-phase images were reconstructed with maximum intensity projection（MIP）, curved planar reconstruction （CPR） and shade-surface displayment （SSD）. The results of the two methods （MSCTU and ultrasonography） were then compared. Results： Ureteric pelvic junction obstruction（UPJO） of the left kidney is 76.19% in boys, and it is obviously higher than other urinary anomalies; the morbidity of hydro-duplex kidneys with hydro-duplex ureter is 84.00%, and most of the patients are girls. Renal function of the diseased kidneys are better in obstruction at ureteropelvic distalis, secretory function of the diseased kidneys exist in severe UPJO, and excretory function is disturbed; renal function of the diseased kidneys is the worst in severe renal hypoplsia and hydro-duplex kidneys. The accordance rate of MSCTU and ultrasonography with operation is 96.3%, 60.04%, respectively. MPR is a facile technique and it is for viewing function and construction of kidneys; CPR, MIP and SSD are for observing whole shape of collecting system, evaluating excretory function of kidneys, defining the site of obstruction and making qualitative diagnosis. Conclusion： Grasping best low-dose delayed enhancement MSCTU scanning time and adopting reasonable methods of image processing can diagnose congenital complex urinary obstruction lesions accurately in children, and it could be selected as one stop choice in diagnosing urinary lesions before operation.