Seo Youngduk, Lee Won Won, Kang Gimun, Shong Min Ho, Joung Kyong Hye, Kim Seong Min, Jun Sungmin
Department of Nuclear Medicine, Chungnam National University Sejong Hospital, Sejong, Republic of Korea.
Hell J Nucl Med. 2023 May-Aug;26(2):84-93. doi: 10.1967/s002449912570. Epub 2023 Aug 4.
In previous fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) studies, tumor segmentation using peritumoral halo layer (PHL; SegPHL) was shown to be reliable and accurate segmentation method in various malignant tumors. We found that the halo layer also was observed on the Tc-pertechnetate (TcO) thyroid single photon emission computed tomography (SPECT)/CT. In the present study, we attempted to apply thyroid segmentation using the perithyroidal halo layer (PTHL; SegPTHL) on TcO thyroid SPECT/CT and compared SegPTHL with CT-based thyroid segmentation (SegCT).
A total of 33 patients (19 females, 14 males; mean age, 46.91±15.7 years old) were enrolled in this study. For SegCT, three-dimensional volume of interest (VOI) of the thyroid was generated via multiple 2-dimensional regions of interest (ROI) along the thyroid margin on transaxial CT images that were manually drawn slice by slice. The PTHL was easily identified by an abrupt increase in layer thickness with minimal or mild distortion of the main thyroid contour, and the thyroid margin for SegPTHL was determined at the innermost portion of PTHL. An automated VOI generation for SegPTHL was performed using the Q. Volumetrix software. The correlation and reliability tests were performed between the quantification parameters of SegPTHL and SegCT.
The PTHL threshold adjusted according to maximal SUV of thyroid were similar to the results of previous SegPHLstudies of F-FDG PET/CT. A good correlation was observed between the thyroid volumes of SegCT and SegPTHL (r=0.725; P<0.0001), although the thyroid volume of SegPTHL was slightly larger than that of SegCT (P=0.0017). The % thyroid uptake (TcTU), total lesion activity (TLA), and mean standardized uptake value (SUVmean) of SegPTHL correlated well with those of SegCT (r=0.9877, 0.9883, 0.9875, respectively; P<0.0001). No significant error was observed between the parameters (i.e., TcTU, TLA, and SUVmean) of SegPTHL and SegCT.
Thyroid segmentation PTHL may be a useful method for reliable quantification of thyroid uptake, because the SPECT/CT parameters of SegPTHL were strongly correlated with those of SegCT, as well as the process of SegPTHL is easier and faster than that of SegCT.
在以往的氟-18-氟脱氧葡萄糖正电子发射断层扫描/计算机断层扫描（F-FDG PET/CT）研究中，使用瘤周晕层（PHL；SegPHL）进行肿瘤分割在各种恶性肿瘤中被证明是一种可靠且准确的分割方法。我们发现，在高锝酸盐（TcO）甲状腺单光子发射计算机断层扫描（SPECT）/CT上也观察到了晕层。在本研究中，我们尝试在TcO甲状腺SPECT/CT上应用甲状腺周晕层（PTHL；SegPTHL）进行甲状腺分割，并将SegPTHL与基于CT的甲状腺分割（SegCT）进行比较。
本研究共纳入33例患者（19例女性，14例男性；平均年龄46.91±15.7岁）。对于SegCT，通过在横轴位CT图像上沿着甲状腺边缘逐片手动绘制多个二维感兴趣区（ROI）来生成甲状腺的三维感兴趣区（VOI）。PTHL可通过层厚度突然增加且甲状腺主要轮廓仅有最小程度或轻度变形来轻松识别，SegPTHL的甲状腺边缘在PTHL的最内侧部分确定。使用Q. Volumetrix软件对SegPTHL进行自动VOI生成。对SegPTHL和SegCT的量化参数进行相关性和可靠性测试。
根据甲状腺最大SUV调整的PTHL阈值与以往F-FDG PET/CT的SegPHL研究结果相似。SegCT和SegPTHL的甲状腺体积之间观察到良好的相关性（r = 0.725；P < 0.0001），尽管SegPTHL的甲状腺体积略大于SegCT（P = 0.0017）。SegPTHL的甲状腺摄取百分比（TcTU）、总病变活性（TLA）和平均标准化摄取值（SUVmean）与SegCT的相关性良好（分别为r = 0.9877、0.9883、0.9875；P < 0.0001）。SegPTHL和SegCT的参数（即TcTU、TLA和SUVmean）之间未观察到显著误差。
甲状腺分割PTHL可能是一种用于可靠量化甲状腺摄取的有用方法，因为SegPTHL的SPECT/CT参数与SegCT的参数高度相关，并且SegPTHL的过程比SegCT更容易、更快。
