[18F]FDG PET/MRI combined with chest HRCT in early cancer detection: a retrospective study of 3020 asymptomatic subjects

Abstract

Purpose: PET/MRI has become an important medical imaging approach in clinical practice. In this study, we retrospectively investigated the detectability of fluorine-18 (¹⁸F)-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging ([¹⁸F]FDG PET/MRI) combined with chest computerized tomography (CT) for early cancer in a large cohort of asymptomatic subjects.

Methods: This study included a total of 3020 asymptomatic subjects who underwent whole-body [¹⁸F]FDG PET/MRI and chest HRCT examinations. All subjects received a 2-4-year follow-up for cancer development. Cancer detection rate, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the [¹⁸F]FDG PET/MRI with or without chest HRCT were calculated and analyzed.

Results: Sixty-one subjects were pathologically diagnosed with cancers, among which 59 were correctly detected by [¹⁸F]FDG PET/MRI combined with chest HRCT. Of the 59 patients (32 with lung cancer, 9 with breast cancer, 6 with thyroid cancer, 5 with colon cancer, 3 with renal cancer, 1 with prostate cancer, 1 with gastric cancer, 1 with endometrial cancer, and 1 with lymphoma), 54 (91.5%) were at stage 0 or stage I (according to the 8th edition of the tumor-node-metastasis [TNM] staging system), 33 (55.9%) were detected by PET/MRI alone (27 with non-lung cancers and 6 with lung cancer). Cancer detection rate, sensitivity, specificity, PPV, and NPV for PET/MRI combined with chest CT were 2.0%, 96.7%, 99.6%, 83.1%, and 99.9%, respectively. For PET/MRI alone, the metrics were 1.1%, 54.1%, 99.6%, 73.3%, and 99.1%, respectively, and for PET/MRI in non-lung cancers, the metrics were 0.9%, 93.1%, 99.6%, 69.2%, and 99.9%, respectively.

Conclusions: [¹⁸F]FDG PET/MRI holds great promise for the early detection of non-lung cancers, while it seems insufficient for detecting early-stage lung cancers. Chest HRCT can be complementary to whole-body PET/MRI for early cancer detection.

Trial registration: ChiCTR2200060041. Registered 16 May 2022. Public site: https://www.chictr.org.cn/index.html.

Keywords: Early detection of cancer; Glucose metabolism; Positron emission tomography/magnetic resonance imaging (PET/MRI).

Fig. 1

Flowchart describing the study of [¹⁸F]FDG PET/MRI combined with chest HRCT. The diagnostic path indicates how cancers in asymptomatic subjects were detected and identified

Fig. 2

Distribution of cancers detect by PET/MRI combined with chest HRCT. Nine types of cancers were detected using PET/MR combined with chest CT, with various-colored dots representing distinctive types of cancers, and each dot representing 1 case. A total of 59 subjects were detected with cancers, including 25 males and 34 females

Fig. 3

Types and sizes of the 32 lung cancers. Diagnostic performance of the PET/MR for solid (yellow dot), part-solid (blue dot), and ground-glass (red dot) lung cancers

Fig. 4

Axial PET/MRI images of a 65-year-old man with renal clear cell carcinoma. A lesion (arrow) was seen in the left kidney as an area of low signal intensity on the T1-weighted image (a, in phase; b, out of phase) and diffusion-weighted image (f), with cystic necrosis on the T2-weighted image (c). Mild FDG uptake was observed on the PET image (d) and on the fused T2-weighted and PET image (e)

Fig. 5

Axial CT and PET/MRI images of a 48-year-old woman with lung cancer. A ground-glass density nodule (arrow) is seen in the anterior upper lobe of the right lung with a size of 1.0 × 0.8 cm (a), which is negative on the T1-weighted image (b), diffusion-weighted image (c), T2-weighted image (d), PET (e), and fused T2-weighted and PET image (f). Pathology confirmed to be adenocarcinoma