Binse I, Poeppel T D, Ruhlmann M, Gomez B, Umutlu L, Bockisch A, Rosenbaum-Krumme S J
Medical Faculty, Department of Nuclear Medicine, University of Duisburg-Essen, Hufelandstr. 55, 45122, Essen, Germany.
Medical Faculty, Department of Radiology, University of Duisburg-Essen, Essen, Germany.
Eur J Nucl Med Mol Imaging. 2016 Jun;43(6):1011-7. doi: 10.1007/s00259-015-3288-y. Epub 2015 Dec 19.
The aim of this study was to compare integrated PET/CT and PET/MRI for their usefulness in detecting and categorizing cervical iodine-positive lesions in patients with differentiated thyroid cancer using (124)I as tracer.
The study group comprised 65 patients at high risk of iodine-positive metastasis who underwent PET/CT (low-dose CT scan, PET acquisition time 2 min; PET/CT2) followed by PET/MRI of the neck 24 h after (124)I administration. PET images from both modalities were analysed for the numbers of tracer-positive lesions. Two different acquisition times were used for the comparisons, one matching the PET/CT2 acquisition time (2 min, PET/MRI2) and the other covering the whole MRI scan time (30 min, PET/MRI30). Iodine-positive lesions were categorized as metastasis, thyroid remnant or inconclusive according to their location on the PET/CT images. Morphological information provided by MRI was considered for evaluation of lesions on PET/MRI and for volume information.
PET/MRI2 detected significantly more iodine-positive metastases and thyroid remnants than PET/CT2 (72 vs. 60, p = 0.002, and 100 vs. 80, p = 0.001, respectively), but the numbers of patients with at least one tumour lesion identified were not significantly different (21/65 vs. 17/65 patients). PET/MRI30 tended to detect more PET-positive metastases than PET/MRI2 (88 vs. 72), but the difference was not significant (p = 0.07). Of 21 lesions classified as inconclusive on PET/CT, 5 were assigned to metastasis or thyroid remnant when evaluated by PET/MRI. Volume information was available in 34 % of iodine-positive metastases and 2 % of thyroid remnants on PET/MRI.
PET/MRI of the neck was found to be superior to PET/CT in detecting iodine-positive lesions. This was attributed to the higher sensitivity of the PET component, Although helpful in some cases, we found no substantial advantage of PET/MRI over PET/CT in categorizing iodine-positive lesions as either metastasis or thyroid remnant. Volume information provided by MRI for some iodine-positive lesions might be useful in dosimetry.
本研究旨在比较PET/CT和PET/MRI在以（124）I作为示踪剂检测和分类分化型甲状腺癌患者颈部碘阳性病变中的应用价值。
研究组包括65例有碘阳性转移高风险的患者，他们在服用（124）I后24小时先接受PET/CT（低剂量CT扫描，PET采集时间2分钟；PET/CT2），随后进行颈部PET/MRI检查。分析两种检查方式的PET图像上示踪剂阳性病变的数量。比较时采用了两种不同的采集时间，一种与PET/CT2的采集时间匹配（2分钟，PET/MRI2），另一种涵盖整个MRI扫描时间（30分钟，PET/MRI30）。根据PET/CT图像上碘阳性病变的位置，将其分类为转移灶、甲状腺残留或不确定病变。在评估PET/MRI上的病变以及获取体积信息时，考虑了MRI提供的形态学信息。
PET/MRI2检测到的碘阳性转移灶和甲状腺残留明显多于PET/CT2（分别为72个对60个，p = 0.002，以及100个对80个，p = 0.001），但至少发现一处肿瘤病变的患者数量无显著差异（21/65例对17/65例）。PET/MRI30检测到的PET阳性转移灶倾向于多于PET/MRI2（88个对72个），但差异不显著（p = 0.07）。在PET/CT上分类为不确定的21个病变中，经PET/MRI评估后，有5个被归类为转移灶或甲状腺残留。PET/MRI上34%的碘阳性转移灶和2%的甲状腺残留可获得体积信息。
发现颈部PET/MRI在检测碘阳性病变方面优于PET/CT。这归因于PET部分更高的灵敏度。虽然在某些情况下有帮助，但我们发现PET/MRI在将碘阳性病变分类为转移灶或甲状腺残留方面相对于PET/CT没有实质性优势。MRI为一些碘阳性病变提供的体积信息可能在剂量测定中有用。
