黄色肉芽肿性肾盂肾炎的多层CT动态增强表现特征

目的 分析黄色肉芽肿性肾盂肾炎(XGP)的多层CT动态增强表现特点.方法 自2007年1月至2010年10月间,我院共5例经手术病理证实的XGP患者术前接受多层CT平扫及多期增强扫描.与病理组织学结果对照,本研究回顾性分析XGP的多层CT平扫及动态增强表现.结果 5例患者全部为单肾受累,左肾2例,右肾3例.CT表现分两型:(1)全肾弥漫性病变3例,全部合并肾结石及中-重度肾积水,表现为患肾肾盂肾盏显著扩张,腔壁增厚,并不均匀延迟强化;肾盏周围见串珠状低密度区,病理为多发微小脓肿;3例均见病灶内斑点或斑片状脂肪密度区,肾周脂肪间隙模糊及肾周筋膜增厚;1例腰大肌、竖脊肌及腹壁脓肿形成.(2)肾脏局灶性病变2例,1例为单发囊性低密度灶,夹杂斑片状脂肪密度区,壁薄,多期增强扫描囊壁呈延迟强化,囊腔无强化,囊壁周围散在蜂窝状低密度区,病理为微小脓肿;1例为单发囊性混杂密度灶,夹杂斑片状脂肪密度区,壁薄,多期增强扫描无强化.2例患者病灶周围肾周筋膜增厚,但均未发现结石征象.结论 CT能准确评价XGP肾脏受累程度及肾外炎性病变的浸润范围,肾结石、肾积水基础上病变区低密度脂肪沉积及肾盏周围肾实质内串珠状微小脓肿高度提示该病诊断.

The imaging features of xanthogranulomatous pyelonephritis on multi-slice helical CT examinations

Objective To analyze the imaging features of xanthogranulomatous pyelonephritis(XGP)on multi-slice helical CT examinations. Methods From Jan 2007 to October 2010, 5 patients with XGP received tri-phase contrast-enhanced multi-slice helical CT examination in our institution. All of them were finally confirmed by postoperative histopathology. The CT characteristics of XGP were studied retrospectively in contrast with the pathological findings. Results Five patients were single kidney involvement, including left kidney in 2 cases, and right kidney in 3 cases. CT manifestations can be divided into two types: (1) renal diffuse lesions were in 3 cases, all combined with renal calculi and moderate-severe hydronephrosis, performing that renal pelvis and calyceal were significantly dilated, the parietal thickening, and delayed enhancement were not uniform. Surrounding the renal calyceal, the honeycomb、beaded low-density areas can be observed, which were confirmed small abcess by pathology; spots or patchy areas of fat can be found in these 3 cases, all combined with thickening of perinephric fascia and stranding of the perinephric fat, and 1 case with psoas muscle, erector spinae and abdominal abscess. (2) renal focal lesions were in 2 cases, one case showed single cystic lesion, inclusion of patchy areas of fat density. The wall was thin, which multi-phase scans performed as delayed enhancement, and the cavity had no enhancement. Surrounding the wall, the honeycomb, beaded low-density areas can also be observed ,which were confirmed small abcess by pathology; the other presented single mixed-density cystic lesion, which patchy areas of fat density can be observed below the left wall. The wall was also thin and had no enhancement in multi-phase scans. The perinephric fascia was thickened, but no positive stones were found in the 2 cases. Conclusions CT can accurately evaluate the degree of renal involvement and the extention of peri- and pararenal inflammation in XGP. The fat density and honeycomb-like small abscess is highly suggestive of this disease.