^(18)F-FDG PET/CT在继发性肾淋巴瘤与肾脏免疫性疾病鉴别诊断中的价值

Value of ^(18)F-FDG PET/CT in the differentiation of secondary renal lymphoma and renal immune disease

目的探讨^(18)F-氟脱氧葡萄糖(FDG)PET/CT对继发性肾淋巴瘤(SRL)的诊断价值,并与肾脏免疫性疾病(RID)进行鉴别分析。方法回顾性分析2017年12月至2020年12月于天津市第一中心医院行^(18)F-FDG PET/CT检查并经组织病理学检查证实或临床综合诊断确诊的12例SRL患者的临床和影像学资料,其中男性7例、女性5例,年龄(50±15)岁,设为SRL组。同时选取^(18)F-FDG PET/CT显像阳性、最终诊断为RID的患者10例,其中IgG4相关性肾病2例、肾抗中性粒细胞胞浆抗体相关性血管炎8例;男性5例、女性5例,年龄(60±10)岁,设为RID组。选取^(18)F-FDG PET/CT显像肾脏正常的健康受检者10例,其中男性5名、女性5名,年龄(55±10)岁,设为正常对照组。观察和记录肾脏以及肾外组织受累的^(18)F-FDG PET/CT影像学表现,测量并计算肾脏病变或肾皮质最大标准化摄取值(SUV_(max))、肾脏病变或肾皮质SUV_(max)与肝脏平均标准化摄取值(SUV_(mean))的比值(SUV_(ratio))及肾外受累组织SUV_(max)。3组受检者SUV_(max)、SUV_(ratio)的比较采用单因素方差分析,SRL组与RID组肾外受累病变^(18)F-FDG摄取SUV_(max)的比较采用独立样本t检验。结果12例SRL患者中,受累肾脏^(18)F-FDG PET/CT显像表现为双侧肾脏多发结节与肿物型6例,肾脏弥漫性肿胀型6例,病变摄取^(18)F-FDG均异常增高。10例RID患者中,受累肾脏^(18)F-FDG PET/CT显像均表现为双肾弥漫性肿胀型,肾实质弥漫性^(18)F-FDG摄取增高,与肾脏弥漫性肿胀型SRL表现相似。在肾外受累病变方面,RID组多有常见好发的累及部位,SRL组多伴全身不同组织脏器的受累,分布无规律性。SRL组患者肾脏病变的SUV_(max)、SUV_(ratio)显著高于RID组(21.88±12.04对9.09±3.51、11.38±6.52对3.67±1.12),2组肾脏病变的SUV_(max)、SUV_(ratio)亦均显著高于正常对照组(SUV_(max)=3.23±0.39、SUV_(ratio)=1.47±0.25),且差异均有统计学意义(F=17.189、18.361,均P<0.001)。SRL组肾外受累病变的SUV_(max)明显高于RID组(27.67±15.09对7.55±3.70),且差异有统计学意义(t=-3.889,P=0.001)。结论^(18)F-FDG PET/CT对SRL的诊断和全身受累范围的评估有较好的临床应用价值,且有助于与RID的鉴别。

Objective To evaluate the diagnostic value of ^(18)F-fluorodeoxyglucose(FDG)PET/CT imaging in patients with secondary renal lymphoma(SRL)and its differential analysis with renal immune disease(RID).Methods The ^(18)F-FDG PET/CT images and clinical characteristics of 12 patients with SRL confirmed by histopathological examination or clinical comprehensive diagnosis in Tianjin First Central Hospital from December 2017 to December 2020 were analyzed retrospectively.The patients in the SRL group comprised 7 males and 5 females,aged 50±15 years.At the same time,10 patients with positive ^(18)F-FDG PET/CT imaging and final diagnosis of RID were selected,including 2 cases of IgG4-related kidney disease and 8 cases of antineutrophil cytoplasmic antibody-associated vasculitis.These 5 males and 5 females,aged 60±10 years,comprised the RID group.Ten healthy subjects with normal kidneys by ^(18)F-FDG PET/CT imaging were selected as the healthy control group(5 males and 5 females,aged 55±10 years).The ^(18)F-FDG PET/CT features of renal and extrarenal invasion were observed and recorded.The maximal standardized uptake value(SUV_(max))of renal lesion or renal cortex,the ratio of SUV_(max) in renal lesion or renal cortex to mean standardized uptake value(SUV_(mean))of liver,and SUV_(max) of extrarenal invasions were measured and calculated.One-way ANOVA was used to compare SUV_(max) and ratio of standardized uptake value(SUV_(ratio))among the three groups,and independent sample t test was used to compare SUV_(max) of extrarenal ^(18)F-FDG uptake in the SRL group and RID group.Results The 12 patients with SRL exhibited multifocal masses(n=6)and diffuse nephromegaly(n=6)in bilater kidneys with abnormally increased ^(18)F-FDG uptake.In 10 patients with RID,the ^(18)F-FDG PET/CT imaging of the affected kidneys showed bilateral diffuse nephromegaly with increased ^(18)F-FDG uptake of renal parenchyma,which was similar to diffuse nephromegaly in SRL.However,in terms of extrarenal involvement,the patients in the RID group had common sites of involvement,and the patients in the SRL group were mostly associated with the involvement of different tissues and organs of the whole body,with irregular distribution.Statistical analysis showed that SUV_(max) and SUV_(ratio) of renal lesions in the SRL group were significantly higher than those in the RID group(21.88±12.04 vs.9.09±3.51 and 11.38±6.52 vs.3.67±1.12,respectively),and SUV_(max) and SUV_(ratio) of renal lesions in the two groups were significantly higher than those in the healthy control group(SUV_(max)=3.23±0.39,SUV_(ratio)=1.47±0.25;F=17.189,18.361;both P<0.001).^(18)F-FDG SUV_(max) of extrarenal lesions in the SRL group was significantly higher than that in the RID group(27.67±15.09 vs.7.55±3.70,t=-3.889,P=0.001).Conclusion ^(18)F-FDG PET/CT has a good clinical value in the diagnosis of SRL and the evaluation of systemic involvement,and it is helpful in distinguishing SRL from RID.