PET/MRI assessment of lung nodules in primary abdominal malignancies: sensitivity and outcome analysis

• Published in: European journal of nuclear medicine and molecular imaging Vol. 48; no. 6; pp. 1976 - 1986
• Main Authors: Biondetti, Pierpaolo, Vangel, Mark G., Lahoud, Rita M., Furtado, Felipe S., Rosen, Bruce R., Groshar, David, Canamaque, Lina G., Umutlu, Lale, Zhang, Eric W., Mahmood, Umar, Digumarthy, Subba R., Shepard, Jo-Anne O., Catalano, Onofrio A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2021; Springer Nature B.V
• Subjects: Abdomen; Avidity; Cardiology; Chest; Computed tomography; Fluorine isotopes; Gastric cancer; Imaging; Lung nodules; Lungs; Magnetic resonance imaging; Malignancy; Medicine; Medicine & Public Health; Metastases; Nodules; Nuclear Medicine; Oncology; Oncology - Chest; Original Article; Orthopedics; Position (location); Positron emission; Radiology; Sensitivity analysis; Thorax; Tomography; PET/MRI; PET/MR; Pulmonary nodule; PET/CT; Lung nodule
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-020-05113-1

Purpose To evaluate PET/MR lung nodule detection compared to PET/CT or CT, to determine growth of nodules missed by PET/MR, and to investigate the impact of missed nodules on clinical management in primary abdominal malignancies. Methods This retrospective IRB-approved study included [18F]-FDG PET/MR in 126 patients. All had standard of care chest imaging (SCI) with diagnostic chest CT or PET/CT within 6 weeks of PET/MR that served as standard of reference. Two radiologists assessed lung nodules (size, location, consistency, position, and [18F]-FDG avidity) on SCI and PET/MR. A side-by-side analysis of nodules on SCI and PET/MR was performed. The nodules missed on PET/MR were assessed on follow-up SCI to ascertain their growth (≥ 2 mm); their impact on management was also investigated. Results A total of 505 nodules (mean 4 mm, range 1–23 mm) were detected by SCI in 89/126 patients (66M:60F, mean age 60 years). PET/MR detected 61 nodules for a sensitivity of 28.1% for patient and 12.1% for nodule, with higher sensitivity for > 7 mm nodules (< 30% and > 70% respectively, p  < 0.05). 75/337 (22.3%) of the nodules missed on PET/MR (follow-up mean 736 days) demonstrated growth. In patients positive for nodules at SCI and negative at PET/MR, missed nodules did not influence patients’ management. Conclusions Sensitivity of lung nodule detection on PET/MR is affected by nodule size and is lower than SCI. 22.3% of missed nodules increased on follow-up likely representing metastases. Although this did not impact clinical management in study group with primary abdominal malignancy, largely composed of extra-thoracic advanced stage cancers, with possible different implications in patients without extra-thoracic spread.