PURPOSE To investigate the added value of dual-time-point 18F-FDG PET/CT imaging in the diagnosis of colorectal cancer liver metastases (CRLM). METHODS One hundred and eight patients with CRLM preoperatively underwent a dual-time-point 18F-FDG PET/CT scan. All hepatic lesions were diagnosed by histopathology. The diagnostic sensitivity of 18F-FDG PET/CT for CRLM was calculated on early scan and delayed scan, respectively. The McNemar test was used to test the differences of the sensitivity and the specificity between early scan and delayed scan. RESULTS On a per-patient basis, no significant difference in sensitivity was found between early scan and delayed scan (92.93% vs. 96.97%, P = 0.125). The per-patient specificity of early and delayed scans was 77.78%. On a per-lesion basis, overall sensitivity of delayed scan was significantly higher than that of early scan (83.49% vs. 76.61%, P < 0.001). The per-lesion specificity of early and delayed scans was 69.23%. For the lesion size of CRLM ≤ 10 mm, delayed imaging had significantly higher sensitivity than early imaging (47.17% vs. 26.42%, P < 0.001). However, for CRLM > 10 mm, there was no significant difference in sensitivity between early and delayed scans (92.73% vs. 95.15%, P = 0.125). Of the detected 182 liver metastatic lesions on delayed scan, the SUVmax on delayed scan was significantly higher than that on early scan (12.13 ± 7.13 vs. 9.16 ± 4.74, P < 0.001). The SUVmean of the normal liver on delayed scan was significantly lower than that on early scan (1.91 ± 0.29 vs. 2.33 ± 0.31, P < 0.001). The tumor to normal background ratio on delayed scan was significantly higher than that on early scan (6.59 ± 4.43 vs. 4.02 ± 2.23, P < 0.001). CONCLUSION The dual-time-point 18F-FDG PET/CT imaging might detect more CRLM lesions compared with single-time-point imaging, especially for small (< 10 mm) lesions.

中文翻译：

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双时间点18F-FDG PET / CT成像在诊断大肠癌肝转移中的附加价值。

目的探讨双时点18F-FDG PET / CT成像在大肠癌肝转移（CRLM）诊断中的附加价值。方法术前对108例CRLM患者进行了双时间点18F-FDG PET / CT扫描。所有肝脏病变均通过组织病理学诊断。分别在早期扫描和延迟扫描中计算了18F-FDG PET / CT对CRLM的诊断敏感性。McNemar测试用于测试早期扫描和延迟扫描之间的敏感性和特异性差异。结果在每位患者的基础上，早期扫描和延迟扫描之间的敏感性没有显着差异（92.93％比96.97％，P = 0.125）。早期和延迟扫描的每位患者特异性为77.78％。在每个病变的基础上，延迟扫描的总体敏感性显着高于早期扫描（83.49％vs. 76.61％，P <0.001）。早期和延迟扫描的病灶特异性为69.23％。对于CRLM≤10 mm的病变，延迟成像的敏感性明显高于早期成像（47.17％对26.42％，P <0.001）。但是，对于CRLM> 10 mm，早期扫描和延迟扫描之间的灵敏度没有显着差异（92.73％与95.15％，P = 0.125）。在延迟扫描中检测到的182个肝转移病灶中，延迟扫描中的SUVmax显着高于早期扫描中的SUVmax（12.13±7.13对9.16±4.74，P <0.001）。延迟扫描时正常肝脏的SUV平均值明显低于早期扫描时（1.91±0.29 vs. 2.33±0.31，P <0.001）。延迟扫描的肿瘤与正常背景比明显高于早期扫描（6.59±4.43 vs. 4.02±2.23，P <0.001）。结论与单时间点成像相比，双时间点18F-FDG PET / CT成像可能检测到更多的CRLM病变，尤其是对于小（<10 mm）病变。