Fat Fraction Extracted from Whole-Body Magnetic Resonance (WB-MR) in Bone Metastatic Prostate Cancer: Intra- and Inter-Reader Agreement of Single-Slice and Volumetric Measurements
Giorgio Maria Agazzi,
Nunzia Di Meo,
Paolo Rondi,
Chiara Saeli,
Alberto Dalla Volta,
Marika Vezzoli,
Alfredo Berruti,
Andrea Borghesi,
Roberto Maroldi,
Marco Ravanelli,
Davide Farina
Affiliations
Giorgio Maria Agazzi
Neuroradiology Department, ASST Santi Paolo e Carlo, 20142 Milan, Italy
Nunzia Di Meo
Radiology Unit, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Paolo Rondi
Radiology Unit, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Chiara Saeli
Department of Radiology, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Alberto Dalla Volta
Department of Oncology, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Marika Vezzoli
Department of Molecular and Translational, University of Brescia, Piazza del Mercato 15, 25123 Brescia, Italy
Alfredo Berruti
Department of Oncology, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Andrea Borghesi
Radiology Unit, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Roberto Maroldi
Radiology Unit, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Marco Ravanelli
Radiology Unit, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Davide Farina
Radiology Unit, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
Background: This study evaluates the repeatability and reproducibility of fat-fraction percentage (FF%) in whole-body magnetic resonance imaging (WB-MRI) of prostate cancer patients with bone metastatic hormone naive disease. Methods: Patients were selected from the database of a prospective phase-II trial. The treatment response was assessed using the METastasis Reporting and Data System for Prostate (MET-RADS-P). Two operators identified a Small Active Lesion (SAL, <10 mm) and a Large Active Lesion (LAL, ≥10 mm) per patient, performing manual segmentation of lesion volume and the largest cross-sectional area. Measurements were repeated by one operator after two weeks. Intra- and inter-reader agreements were assessed via Interclass Correlation Coefficient (ICC) on first-order radiomics features. Results: Intra-reader ICC showed high repeatability for both SAL and LAL in a single slice (SS) and volumetric (VS) measurements with values ranging from 0.897 to 0.971. Inter-reader ICC ranged from 0.641 to 0.883, indicating moderate to good reproducibility. Spearman’s rho analysis confirmed a strong correlation between SS and VS measurements for SAL (0.817) and a moderate correlation for LAL (0.649). Both intra- and inter-rater agreement exceeded 0.75 for multiple first-order features across lesion sizes. Conclusion: This study suggests that FF% measurements are reproducible, particularly for larger lesions in both SS and VS assessments.
