Noltes Milou E, Kruijff Schelto, Noordzij Walter, Telenga Eef D, Vállez García David, Trofimiuk-Müldner Malgorzata, Opalińska Marta, Hubalewska-Dydejczyk Alicja, Luurtsema Gert, Dierckx Rudi A J O, El Moumni Mostafa, Boellaard Ronald, Brouwers Adrienne H
Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, P.O. Box 30 001, 9700, RB, Groningen, The Netherlands.
EJNMMI Res. 2019 Jul 31;9(1):73. doi: 10.1186/s13550-019-0534-5.
To evaluate the optimal tracer uptake time, the minimal amount of radioactivity and the inter-observer agreement for C-choline positron emission tomography/computed tomography (PET/CT) in patients with primary hyperparathyroidism (pHPT).
Twenty-one patients with biochemically proven pHPT were retrospectively studied after injection of 6.3 ± 1.2 MBq/kg C-choline. PET data of the first nine patients, scanned for up to 60 min, were reconstructed in 10-min frames from 10- to 60-min postinjection (p.i.), mimicking varying C-choline uptake times. Parathyroid adenoma to background contrast ratios were calculated and compared, using standardized uptake values (SUVs). Data was reconstructed with varying scan durations (1, 2.5, 5, and 10 min) at 20-30-min p.i. (established optimal uptake time), mimicking less administered radioactivity. To establish the minimal required radioactivity, the SUVs in the shorter scan durations (1, 2.5, and 5 min) were compared to the 10-min scan duration to determine whether increased variability and/or statistical differences were observed. Four observers analyzed the C-choline PET/CT in four randomized rounds for all patients.
SUVpeak of the adenoma decreased from 30 to 40 p.i. onwards. All adenoma/background contrast ratios did not differ from 20- to 30-min p.i. onwards. The SUVs of adenoma in the scan duration of 1, 2.5, and 5 min all differed significantly from the same SUV in the 10-min scan duration (all p = 0.012). However, the difference in absolute SUV adenoma values was well below 10% and therefore not considered clinically significant. The inter-observer analysis showed that the Fleiss' kappa of the 1-min scan were classified as "moderate," while these values were classified as "good" in the 2.5-, 5-, and 10-min scan duration. Observers scored lower certainty scores in the 1- and 2.5-min scans compared to the 5- and 10-min scan durations.
The optimal time to start PET/CT scanning in patients with pHPT is 20 min after mean injection of 6.3 MBq/kg C-choline, with a recommended scan duration of at least 5 min. Alternatively, the radioactivity dose can be lowered by 50% while keeping a 10-min scan duration without losing the accuracy of C-choline PET/CT interpretation.
评估原发性甲状旁腺功能亢进症（pHPT）患者进行碳-胆碱正电子发射断层扫描/计算机断层扫描（PET/CT）的最佳示踪剂摄取时间、最小放射性剂量以及观察者间的一致性。
对21例经生化检查证实为pHPT的患者进行回顾性研究，这些患者注射了6.3±1.2 MBq/kg的碳-胆碱。对前9例患者进行了长达60分钟的PET扫描，在注射后10至60分钟以10分钟的时间间隔重建PET数据，模拟不同的碳-胆碱摄取时间。使用标准化摄取值（SUV）计算并比较甲状旁腺腺瘤与背景的对比率。在注射后20至30分钟（确定的最佳摄取时间），以不同的扫描时长（1、2.5、5和10分钟）重建数据，模拟减少的放射性剂量。为确定所需的最小放射性剂量，将较短扫描时长（1、2.5和5分钟）的SUV与10分钟扫描时长的SUV进行比较，以确定是否观察到变异性增加和/或统计学差异。四位观察者对所有患者的碳-胆碱PET/CT进行了四轮随机分析。
腺瘤的SUVpeak从注射后30分钟起开始下降。从注射后20至30分钟起，所有腺瘤/背景对比率均无差异。1、2.5和5分钟扫描时长的腺瘤SUV与10分钟扫描时长的同一SUV均有显著差异（均p = 0.012）。然而，腺瘤绝对SUV值的差异远低于10%，因此不认为具有临床意义。观察者间分析显示，1分钟扫描的Fleiss' kappa分类为“中等”，而在2.5、5和10分钟扫描时长时这些值分类为“良好”。与5和10分钟扫描时长相比，观察者在1和2.5分钟扫描中的确定性评分较低。
pHPT患者开始PET/CT扫描的最佳时间是平均注射6.3 MBq/kg碳-胆碱后20分钟，建议扫描时长至少为5分钟。或者，放射性剂量可降低50%，同时保持10分钟扫描时长，而不会丧失碳-胆碱PET/CT解读的准确性。
