Miwa Kenta, Inubushi Masayuki, Wagatsuma Kei, Nagao Michinobu, Murata Taisuke, Koyama Masamichi, Koizumi Mitsuru, Sasaki Masayuki
Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan; Division of Medical Quantum Science, Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Department of Nuclear Medicine, Kawasaki Medical School, 577 Matsushima Kurashiki, Okayama 701-0192, Japan.
Eur J Radiol. 2014 Apr;83(4):715-9. doi: 10.1016/j.ejrad.2013.12.020. Epub 2013 Dec 27.
The present study aimed to determine whether fractal analysis of morphological complexity and intratumoral heterogeneity of FDG uptake can help to differentiate malignant from benign pulmonary nodules.
We retrospectively analyzed data from 54 patients with suspected non-small cell lung cancer (NSCLC) who were examined by FDG PET/CT. Pathological assessments of biopsy specimens confirmed 35 and 19 nodules as NSCLC and inflammatory lesions, respectively. The morphological fractal dimension (m-FD), maximum standardized uptake value (SUV(max)) and density fractal dimension (d-FD) of target nodules were calculated from CT and PET images. Fractal dimension is a quantitative index of morphological complexity and tracer uptake heterogeneity; higher values indicate increased complexity and heterogeneity.
The m-FD, SUV(max) and d-FD significantly differed between malignant and benign pulmonary nodules (p<0.05). Although the diagnostic ability was better for d-FD than m-FD and SUV(max), the difference did not reach statistical significance. Tumor size correlated significantly with SUV(max) (r=0.51, p<0.05), but not with either m-FD or d-FD. Furthermore, m-FD combined with either SUV(max) or d-FD improved diagnostic accuracy to 92.6% and 94.4%, respectively.
The d-FD of intratumoral heterogeneity of FDG uptake can help to differentially diagnose malignant and benign pulmonary nodules. The SUV(max) and d-FD obtained from FDG-PET images provide different types of information that are equally useful for differential diagnoses. Furthermore, the morphological complexity determined by CT combined with heterogeneous FDG uptake determined by PET improved diagnostic accuracy.
本研究旨在确定对FDG摄取的形态复杂性和肿瘤内异质性进行分形分析是否有助于鉴别肺恶性结节与良性结节。
我们回顾性分析了54例疑似非小细胞肺癌（NSCLC）患者的FDG PET/CT检查数据。活检标本的病理评估分别证实35个和19个结节为NSCLC和炎性病变。从CT和PET图像计算目标结节的形态分形维数（m-FD）、最大标准化摄取值（SUV(max)）和密度分形维数（d-FD）。分形维数是形态复杂性和示踪剂摄取异质性的定量指标；值越高表明复杂性和异质性增加。
恶性和良性肺结节之间的m-FD、SUV(max)和d-FD有显著差异（p<0.05）。虽然d-FD的诊断能力优于m-FD和SUV(max)，但差异未达到统计学意义。肿瘤大小与SUV(max)显著相关（r=0.51，p<0.05），但与m-FD或d-FD均无相关性。此外，m-FD与SUV(max)或d-FD联合使用分别将诊断准确性提高到92.6%和94.4%。
FDG摄取的肿瘤内异质性的d-FD有助于鉴别诊断恶性和良性肺结节。从FDG-PET图像获得的SUV(max)和d-FD提供了不同类型的信息，这些信息对鉴别诊断同样有用。此外，CT确定的形态复杂性与PET确定的异质性FDG摄取相结合提高了诊断准确性。
