1 Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA 94143.
2 Department of Medicine, Division of Hematology and Oncology, University of California, San Francisco, San Francisco, CA.
AJR Am J Roentgenol. 2018 Oct;211(4):896-900. doi: 10.2214/AJR.18.19620. Epub 2018 Aug 14.
The purpose of this study was to determine if extended PET acquisition times in the pelvis during PET/MRI increase detection rates of potentially metastatic lymph nodes in patients with rectal cancer.
Our study was approved by the institutional review board of the University of California, San Francisco. Twenty-two patients with biopsy-proven rectal cancer underwent imaging via simultaneous 3-T time-of-flight PET/MRI, with seven undergoing two separate PET/MRI examinations, for a total of 29 studies. Each examination included both a whole-body PET/MRI and a dedicated pelvic PET/MRI with both 3- and 15-minute PET acquisitions for the pelvis. Three radiologists interpreted each examination with PET only, MRI only, then combined PET and MRI examinations, using all available images. Additionally, the 3- and 15-minute PET acquisitions of the pelvis were reviewed separately by a single radiologist.
A total of 94 lymph nodes were identified as abnormal on PET, all with MRI anatomic correlates. Of these, 37 (39.4%) were seen only on the dedicated 15-minute acquisition. Fifty-seven (60.6%) nodes measured 5 mm or less, including 29 (30.9%) seen only on the 15-minute acquisition. Thirty-one (33.0%) nodes measured 5.1-10 mm, including eight (25.8%) seen only on the 15-minute acquisition. Of the 17 subjects imaged for initial staging, 11 (64.7%) were upstaged as a result of the increased PET acquisition time (10 from N1 to N2 and one from N0 to N1).
Longer PET acquisition times during PET/MRI for rectal cancer increases the number of FDG-avid lymph nodes detected without increasing scan time.
本研究旨在确定在盆腔 PET/MRI 中延长 PET 采集时间是否会增加直肠癌患者潜在转移性淋巴结的检出率。
我们的研究得到了加利福尼亚大学旧金山分校机构审查委员会的批准。22 例经活检证实的直肠癌患者接受了同步 3T 飞行时间 PET/MRI 成像检查，其中 7 例患者进行了两次单独的 PET/MRI 检查，总共进行了 29 项研究。每次检查均包括全身 PET/MRI 和专门的盆腔 PET/MRI，盆腔均进行 3 分钟和 15 分钟的 PET 采集。3 名放射科医生分别仅使用 PET、MRI 以及 PET 和 MRI 联合检查来解读每次检查，同时使用所有可用的图像。此外，还由一名放射科医生分别单独对盆腔的 3 分钟和 15 分钟 PET 采集进行评估。
在 PET 上共发现 94 个淋巴结异常，均与 MRI 解剖学相关。其中，37 个（39.4%）仅在专门的 15 分钟采集上可见。57 个（60.6%）淋巴结直径为 5mm 或以下，其中 29 个（30.9%）仅在 15 分钟采集上可见。31 个（33.0%）淋巴结直径为 5.1-10mm，其中 8 个（25.8%）仅在 15 分钟采集上可见。在为初始分期成像的 17 名受试者中，11 名（64.7%）因 PET 采集时间延长而被升级分期（10 名从 N1 升级为 N2，1 名从 N0 升级为 N1）。
在直肠癌的 PET/MRI 中延长 PET 采集时间可增加 FDG 摄取淋巴结的检出数量，而不会增加扫描时间。
