Xu Weina, Yu Shupeng, Ma Ying, Liu Changping, Xin Jun
aRadiology Department bPathology Department, Shenging Hospital of China Medical University, Sanhao Street, Heping District, Shenyang, China.
Nucl Med Commun. 2017 Mar;38(3):259-265. doi: 10.1097/MNM.0000000000000641.
It is known that fluorine-18 fluorodeoxyglucose PET/computed tomography (CT) segmentation algorithms have an impact on the metabolic tumor volume (MTV). This leads to some uncertainties in PET/CT guidance of tumor radiotherapy. The aim of this study was to investigate the effect of segmentation algorithms on the PET/CT-based MTV and their correlations with the gross tumor volumes (GTVs) of cervical primary squamous cell carcinoma.
Fifty-five patients with International Federation of Gynecology and Obstetrics stage Ia∼IIb and histologically proven cervical squamous cell carcinoma were enrolled. A fluorine-18 fluorodeoxyglucose PET/CT scan was performed before definitive surgery. GTV was measured on surgical specimens. MTVs were estimated on PET/CT scans using different segmentation algorithms, including a fixed percentage of the maximum standardized uptake value (20∼60% SUVmax) threshold and iterative adaptive algorithm. We divided all patients into four different groups according to the SUVmax within target volume. The comparisons of absolute values and percentage differences between MTVs by segmentation and GTV were performed in different SUVmax subgroups. The optimal threshold percentage was determined from MTV20%∼MTV60%, and was correlated with SUVmax. The correlation of MTViterative adaptive with GTV was also investigated.
MTV50% and MTV60% were similar to GTV in the SUVmax up to 5 (P>0.05). MTV30%∼MTV60% were similar to GTV (P>0.05) in the 5<SUVmax≤10 group. MTV20%∼MTV60% were similar to GTV (P>0.05) in the 10<SUVmax≤15 group. MTV20% and MTV30% were similar to GTV (P>0.05) in the SUVmax of at least 15 group. MTViterative adaptive was similar to GTV in both total and different SUVmax groups (P>0.05). Significant differences were observed among the fixed percentage method and the optimal threshold percentage was inversely correlated with SUVmax. The iterative adaptive segmentation algorithm led to the highest accuracy (6.66±50.83%). A significantly positive correlation was also observed between MTViterative adaptive and GTV (Pearson's correlation r=0.87, P<0.0001).
MTViterative adaptive is independent of SUVmax, more accurate, and correlated with GTV. Iterative adaptive algorithm segmentation may be more suitable than the fixed percentage threshold method to estimate the tumor volume of cervical primary squamous cell carcinoma.
已知氟 - 18氟脱氧葡萄糖正电子发射断层显像/计算机断层扫描（PET/CT）分割算法会对代谢肿瘤体积（MTV）产生影响。这导致在肿瘤放疗的PET/CT引导中存在一些不确定性。本研究的目的是探讨分割算法对基于PET/CT的MTV的影响及其与宫颈原发性鳞状细胞癌大体肿瘤体积（GTV）的相关性。
纳入55例国际妇产科联盟分期为Ia∼IIb期且经组织学证实为宫颈鳞状细胞癌的患者。在确定性手术前进行氟 - 18氟脱氧葡萄糖PET/CT扫描。在手术标本上测量GTV。使用不同的分割算法在PET/CT扫描上估计MTV，包括最大标准化摄取值的固定百分比（20∼60% SUVmax）阈值和迭代自适应算法。根据靶区内的SUVmax将所有患者分为四个不同组。在不同的SUVmax亚组中对分割后的MTV与GTV之间的绝对值和百分比差异进行比较。从MTV20%∼MTV60%中确定最佳阈值百分比，并与SUVmax相关联。还研究了迭代自适应MTV与GTV的相关性。
在SUVmax高达5时，MTV50%和MTV60%与GTV相似（P>0.05）。在5<SUVmax≤10组中，MTV30%∼MTV60%与GTV相似（P>0.05）。在10<SUVmax≤15组中，MTV20%∼MTV60%与GTV相似（P>0.05）。在SUVmax至少为15组中，MTV20%和MTV30%与GTV相似（P>0.05）。在总体和不同的SUVmax组中，迭代自适应MTV与GTV相似（P>0.05）。在固定百分比方法之间观察到显著差异，并且最佳阈值百分比与SUVmax呈负相关。迭代自适应分割算法导致最高的准确性（6.66±50.83%）。在迭代自适应MTV与GTV之间也观察到显著的正相关（Pearson相关系数r = 0.87，P<0.0001）。
迭代自适应MTV独立于SUVmax，更准确，并且与GTV相关。对于估计宫颈原发性鳞状细胞癌的肿瘤体积，迭代自适应算法分割可能比固定百分比阈值方法更合适。
