Department of Medical Imaging, Princess Margaret Hospital, University Health Network, 610 University Ave., Ste. 3-960, Toronto, ON, M5G 2M9 Canada.
AJR Am J Roentgenol. 2010 Mar;194(3):766-71. doi: 10.2214/AJR.09.3205.
The purpose of this study was to compare FDG PET/CT and contrast-enhanced 64-MDCT of the chest, abdomen, and pelvis in the detection of tumor recurrence in patients with colorectal cancer and an elevated level of carcinoembryonic antigen (CEA).
A retrospective analysis included 50 patients (31 men, 19 women; mean age, 61 years; range, 28-89 years) with 55 clinical events of elevated or increasing CEA level who underwent FDG PET/CT and MDCT for suspected tumor recurrence.
Recurrent or metastatic disease was found in 36 of 55 events (65.5%) of elevated CEA. Fifty-four of 61 tumor sites suspected as tumor recurrence with any imaging technique were found to be local recurrence or metastatic colorectal cancer at final analysis. The other seven sites were one separate malignant tumor (small lymphocytic lymphoma) and six benign lesions. Diagnosis was based on histopathologic findings (n = 27) or clinical and imaging findings (n = 35) during a median follow-up period of 12 months (range, 6-31 months). One site of tumor recurrence was missed prospectively at both MDCT and PET/CT. On an event-based analysis, the sensitivity of PET/CT and MDCT was 97.3% and 70.3% (p = 0.002); the specificity of both techniques was 94.4% (p = 1.0). In a tumor site-based analysis, the sensitivities of PET/CT and MDCT were 98.1% and 66.7% (p < 0.0001), and the specificities were 75% and 62.5% (p = 0.56). Tumors correctly identified with PET/CT and missed with MDCT were local recurrence in the presacral space (n = 5), metastatic subcentimeter lymph nodes (n = 4), peritoneal deposits (n = 3), and recurrences at the periphery of radiofrequency ablated metastatic lesions of the liver (n = 2) and in the abdominal wall (n = 1), liver (n = 1), and uterine cervix (n = 1).
FDG PET/CT has higher sensitivity than MDCT in the identification of sites of recurrent and metastatic disease in patients with colorectal cancer and an elevated CEA level. The two techniques appear to have similar specificity.
本研究旨在比较 FDG PET/CT 和对比增强 64 排 MDCT 在检测结直肠癌患者和癌胚抗原（CEA）水平升高的肿瘤复发中的作用。
回顾性分析了 50 例（男 31 例，女 19 例；平均年龄 61 岁；范围 28-89 岁）患者的 55 例 CEA 水平升高或持续升高的临床事件，这些患者因疑似肿瘤复发而行 FDG PET/CT 和 MDCT 检查。
55 例 CEA 升高的事件中发现 36 例（65.5%）存在复发性或转移性疾病。54 例怀疑肿瘤复发的 61 个肿瘤部位在最终分析中均为局部复发或转移性结直肠癌。另外 7 个部位分别为 1 个孤立性恶性肿瘤（小淋巴细胞淋巴瘤）和 6 个良性病变。诊断基于组织病理学发现（n=27）或临床和影像学发现（n=35），中位随访时间为 12 个月（范围 6-31 个月）。在 MDCT 和 PET/CT 均前瞻性地漏诊了 1 个肿瘤复发部位。基于事件的分析，PET/CT 和 MDCT 的敏感性分别为 97.3%和 70.3%（p=0.002）；两种技术的特异性均为 94.4%（p=1.0）。在肿瘤部位的分析中，PET/CT 和 MDCT 的敏感性分别为 98.1%和 66.7%（p<0.0001），特异性分别为 75%和 62.5%（p=0.56）。用 PET/CT 正确识别而 MDCT 漏诊的肿瘤为骶前空间局部复发（n=5）、亚厘米大小的转移性淋巴结（n=4）、腹膜沉积物（n=3）、射频消融治疗肝转移瘤的边缘复发（n=2）和腹壁（n=1）、肝（n=1）和子宫颈（n=1）。
在结直肠癌患者和 CEA 水平升高的肿瘤复发中，FDG PET/CT 的敏感性高于 MDCT。两种技术的特异性似乎相似。
