Point Spread Function Reconstruction for Integrated 18F-FET PET/MRI in Patients With Glioma: Does It Affect SUVs and Respective Tumor-to-Background Ratios?. (April 2019)

• Record Type: Journal Article
• Authors: Rogasch, Julian Manuel Michael; Albers, Josefine; Steinkrüger, Ferdinand L.; Lukas, Mathias; Wedel, Florian; Amthauer, Holger; Furth, Christian
• Is Part Of: Clinical nuclear medicine. Volume 44:Number 4(2019)
• Publication Date: 2019-04
• Subjects: glioma -- 18F-FET -- PET/MRI -- PSF -- reconstruction -- tumor-to-background ratios; Nuclear medicine -- Periodicals; Radioisotope scanning -- Periodicals; Nuclear Medicine -- Periodicals; 616.07575
• DOI: 10.1097/RLU.0000000000002423
• Languages: English
• ISSNs: 0363-9762

Abstract

Abstract : Purpose: Semiquantitative 18 F-FET PET assessment using the tumor's SUV or tumor-to-background ratios (TBRs) can separate gliomas from peritumoral tissue or progression from pseudoprogression. This study investigated if point spread function (PSF) reconstruction of 18 F-FET PET data affects SUV-based dignity assessment. Materials and Methods: This study is a retrospective analysis of 87 glioma patients (female, 36; male, 51; age, 48 [13–81] years) undergoing 18 F-FET PET/MRI for staging (n = 17) or restaging (n = 70). PET was reconstructed using ordered-subset expectation maximization with and without PSF. Lesions were delineated with semiautomated background-adapted thresholding relative to SUVmax ; background was delineated contralaterally. Comparative measurements with a National Electrical Manufacturers Association International Electrotechnical Commission PET body phantom (sphere-to-background ratios, 8:1 and 4:1) were performed. Results: PSF showed significantly higher tumor SUVmax (median difference, +0.1; interquartile range, 0.04–0.18), SUVmean (+0.05; 0.03–0.08), TBRmax|mean (+0.1; 0.04–0.2), and TBRmean|mean (+0.06; 0.03–0.09) than non-PSF ( P < 0.001). Background SUVmean was unaffected. In patients and phantom, differences between PSF and non-PSF increased with TBR and decreased with lesion's PET volume. Differences only exceeded 0.2 SUV for SUVmax or 0.1 SUV for SUVmean if TBR was greater than 3 and lesion's PET volume was less than 10 mL (d = 27 mm). Dignity assessment by PSF and non-PSF was concordant in all patients examined for staging (cutoff, TBRmean|mean > 1.6; positive, 14; negative, 3) and restaging (cutoff, TBRmax|mean > 2.0; positive, 67; negative, 3). Conclusions: PSF increased tumor SUVmax and SUVmean compared with non-PSF 18 F-FET PET/MRI data, especially in small lesions with high TBR (>3). However, dignity assessment using established TBR cutoffs was not affected.