Naganawa Shotaro, Yoshikawa Takeharu, Yasaka Koichiro, Maeda Eriko, Hayashi Naoto, Abe Osamu
aDepartment of Radiology, Graduate School of Medicine, The University of Tokyo bDepartment of Computational Diagnostic Radiology and Preventive Medicine, The University of Tokyo Hospital, Bunkyo-ku cDepartment of Radiology, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan.
Medicine (Baltimore). 2017 Nov;96(46):e8832. doi: 10.1097/MD.0000000000008832.
Although delayed-time-point imaging is expected to improve the results of [F]-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT), how examinees will benefit from dual-time-point imaging versus initial-time-point imaging alone, remains unclear. This study investigated the role of delayed-time-point imaging in improving the results of abdominal and pelvic cancer screening using FDG-PET/CT.This retrospective review included 3131 screening results (average subject age: 55.5 years, range: 40-88 years). First, 2 nuclear medicine physicians tentatively evaluated whole-body initial-time-point PET/CT scans. Subsequently, delayed-time-point imaging of the abdomen and pelvis was performed approximately 150 min after FDG injection, followed by re-evaluation for necessary changes. All changed records were retrospectively reviewed and classified as either lesions that were found in initial-time-point images but were changed into negative by adding delayed scan or newly detected findings of suspected malignancy on delayed-time-point images; lesions suspected to be malignant were subjected to further pathologic review. Diagnostic performance according to sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated and compared between initial-time-point and dual-time-point imaging.Fifty-four records were changed after addition of the delayed-time-point imaging. Of the 105 suspected malignancies on initial-time-point images, 10 were changed into negative following the delayed scan. In addition, 44 lesions were newly detected as suspected malignancies on delayed-time-point images. Thirty-six lesions were proven to be pathologically malignant. Of these, 26 were detected on initial-time-point images, and 8 lesions (gastrointestinal adenocarcinoma, 6; prostate adenocarcinoma, 2) were observed on delayed-time-point images. The sensitivity of dual-time-point imaging (58.6% [34/58]) was significantly higher than that of initial-time-point imaging only (44.8% [26/58]) (P = .005); however, specificity and accuracy of dual-time-point imaging (96.6% [2968/3073] and 95.9% [3002/3131], respectively) were significantly lower than those of initial-time-point imaging only (97.4% [2994/3073] and 96.5% [3020/3131], respectively) (P < .0001 and P = .013, respectively). There were no significant differences in PPV (initial-time-point imaging: 24.8% [26/105], dual-time-point imaging: 24.5% [34/139]) and NPV (98.9% [2994/3026] and 99.2% [2968/3073], respectively).The inclusion of delayed PET/CT in screening examinations facilitated the detection of pathologically malignant lesions, particularly in the gastrointestinal tract, while also detecting benign and false-negative lesions.
尽管延迟时间点成像有望改善[F]-氟脱氧葡萄糖（FDG）-正电子发射断层扫描/计算机断层扫描（PET/CT）的结果，但受检者如何从双时间点成像而非仅初始时间点成像中获益仍不清楚。本研究调查了延迟时间点成像在使用FDG-PET/CT改善腹部和盆腔癌症筛查结果中的作用。这项回顾性研究纳入了3131例筛查结果（受试者平均年龄：55.5岁，范围：40 - 88岁）。首先，2名核医学医师初步评估全身初始时间点PET/CT扫描。随后，在FDG注射后约150分钟进行腹部和盆腔的延迟时间点成像，然后重新评估是否有必要的变化。对所有变化记录进行回顾性审查，并分类为在初始时间点图像中发现但通过添加延迟扫描变为阴性的病变，或在延迟时间点图像上新检测到的疑似恶性病变；疑似恶性的病变进行进一步病理检查。计算并比较初始时间点成像和双时间点成像在敏感性、特异性、准确性、阳性预测值（PPV）和阴性预测值（NPV）方面的诊断性能。添加延迟时间点成像后，54条记录发生了变化。在初始时间点图像上的105例疑似恶性病变中，10例在延迟扫描后变为阴性。此外，在延迟时间点图像上新检测到44例疑似恶性病变。36例病变经病理证实为恶性。其中，26例在初始时间点图像上被检测到，8例病变（胃肠道腺癌6例；前列腺腺癌2例）在延迟时间点图像上被观察到。双时间点成像的敏感性（58.6% [34/58]）显著高于仅初始时间点成像（44.8% [26/58]）（P = 0.005）；然而，双时间点成像的特异性和准确性（分别为96.6% [2968/3073]和95.9% [3002/3131]）显著低于仅初始时间点成像（分别为97.4% [2994/3073]和96.5% [3020/3131]）（分别为P < 0.0001和P = 0.013）。PPV（初始时间点成像：24.8% [26/105]，双时间点成像：24.5% [34/139]）和NPV（分别为98.9% [2994/3026]和99.2% [2968/3073]）无显著差异。在筛查检查中加入延迟PET/CT有助于检测病理恶性病变，特别是在胃肠道，同时也能检测到良性和假阴性病变。
