18氟-脱氧葡萄糖正电子发射计算机断层成像术对意外发现结直肠局限性高代谢灶的良恶性病变诊断价值

Clinical diagnostic value of 18F-FDG PET-CT in incidental finding of focal hypermetabolism focus in the colon and rectum

目的探讨18氟－脱氧葡萄糖正电子发射计算机断层成像术（18F-FDGPET—CT）全身显像检查中意外发现的结直肠局限性高代谢灶摄取程度及其功能一解剖形态特征对其良恶性病变鉴别诊断的价值。方法回顾性分析2010年1月至2012年2月间在解放军第一一三医院进行PET—CT显像时意外发现结直肠局部高代谢灶的37例患者的临床和影像学资料。根据最终的临床诊断（9例经手术及术后病理证实，15例经肠镜检查证实，13例经临床随访明确）分为恶性病变、良性占位病变（包括癌前病变）、炎性病变和生理性摄取4组，对局部高代谢灶的放射性摄取程度（病灶最大标准摄取值，SUVmax）和延迟显像的变化（滞留指数，RI）进行组间比较，采用方差分析进行数据处理。结果37例病灶中，恶性病变11例、良性占位性病变9例，炎性病变9例，生理性摄取8例，其SUVmax分别为6．3±3．7、8．8±6．5、5．2±1．4和3．8±0．9，R1分别为0．3±0．2、0．4±0．1、0．3±0．2、0．4±0．2。肿瘤组（良性和恶性）SUVmax为7．6±5．6，明显高于非肿瘤组（炎性和生理性摄取）的4．7±1．5（P〈0．05）；但良性、恶性肿瘤间及炎性与生理性摄取间SUVmax的差异均无统计学意义（P〉0．05）。4组病灶RI的差异也无统计学意义（P〉0．05）。结论在PET显像中，通过意外发现的结直肠局限性FDG高代谢灶可以探查到一些潜在的早期结直肠的恶性肿瘤或癌前病变。这些高代谢灶的SUVmax值对肿瘤与炎性和生理性摄取的鉴别有诊断价值，但对良、恶性病变的鉴别无意义。

Objective To investigate the value of incidental focal 18F-FDG uptake in the colon and rectum and characteristics of functional anatomic form for differential diagnosis of colorectal benign or malignant diseases. Methods Clinical data and images of incidental focal hypermetabolism focus in colon and rectum of 37 individuals undergoing 18F-FDG PET-CT were analyzed retrospectively. According to the eventual outcomes of pathological examination and clinical follow-up, these cases were divided into four subgroups： malignant disease, benign tumor （including precancerous change）, inflammation and physiological uptake. Radioactive uptake level （SUVmax）and change of delayed imaging （RI） of focal hypermetabolism focus were compared between groups. The data analysis was performed using variance analysis. Results The average SUVmax was 6.3±3.7, 8.8±6.5, 5.2±1.4, and 3.8±0.9 in malignant disease（n=11）, benign（precancerous） tumor（n=9）, inflammation（n=9） and physiological uptaking （n=8） respectively. The average SUVmax was 7.6±5.6 in benign and malignant tumor, and 4.7±1.5 in inflammation and physiological uptake. The distinction of average SUVmax was not statistically significant between benign and malignant tumor or inflammation and physiological uptake. But it was higher in tumors as compared to inflammation or physiological uptake with a statistically difference （P〈0.05）. The RI was 0.3±0.2, 0.4±0.1, 0.3±0.2, 0.4±0.2 in above 4 groups respectively, and the differences were not statistically significant. Conclusions The incidental focal hypermetabolism focus in the colon the rectum during ~SF-FDG PET-CT may indicate potential colorectal malignant diseases and precancerous lesions. SUVmax value in focal hypermetabolism focus in the colon and rectum can help to distinguish tumor from inflammation or physiological uptake. But there is no diagnostic value for distinguishing malignant disease from benign tumor.