18F-FDG, 11C-Methionine, and 68Ga-Pentixafor PET/CT in Patients with Smoldering Multiple Myeloma: Imaging Pattern and Clinical Features

• Main Authors: Xiang Zhou, Alexander Dierks, Olivia Kertels, Malte Kircher, Andreas Schirbel, Samuel Samnick, Andreas K. Buck, Sebastian Knorz, David Böckle, Lukas Scheller, Janin Messerschmidt, Mohammad Barakat, K. Martin Kortüm, Leo Rasche, Hermann Einsele, Constantin Lapa
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Cancers
• Subjects: 18F-FDG PET/CT; 11C-Methionine PET/CT; 68Ga-Pentixafor PET/CT; smoldering myeloma
• Online Access: https://www.mdpi.com/2072-6694/12/8/2333

This study aimed to explore the correlation between imaging patterns and clinical features in patients with smoldering multiple myeloma (SMM) who simultaneously underwent 18F-FDG, 11C-Methionine, and 68Ga-Pentixafor positron emission tomography/computed tomography (PET/CT). We retrieved and analyzed clinical characteristics and PET imaging data of 10 patients with SMM. We found a significant correlation between bone marrow (BM) plasma cell (PC) infiltration and mean standardized uptake values (SUV_mean) of lumbar vertebrae L2-L4 on 11C-Methionine PET/CT scans (<i>r</i> = 0.676, <i>p</i> = 0.031) and 68Ga-Pentixafor PET/CT scans (<i>r</i> = 0.839, <i>p</i> = 0.002). However, there was no significant correlation between BM involvement and SUV_mean of lumbar vertebrae L2-L4 on 18F-FDG PET/CT scans (<i>r</i> = 0.558, <i>p</i> = 0.093). Similarly, mean target-to-background ratios (TBR_mean) of lumbar vertebrae L2-L4 also correlated with bone marrow plasma cell (BMPC) infiltration in 11C-Methionine PET/CT (<i>r</i> = 0.789, <i>p</i> = 0.007) and 68Ga-Pentixafor PET/CT (<i>r</i> = 0.724, <i>p</i> = 0.018) PET/CT. In contrast, we did not observe a significant correlation between BMPC infiltration rate and TBR_mean in 18F-FDG PET/CT (<i>r</i> = 0.355, <i>p</i> = 0.313). Additionally, on 11C-Methionine PET/CT scans, we found a significant correlation between BMPC infiltration and TBR_max of lumbar vertebrae L2-L4 (<i>r</i> = 0.642, <i>p</i> = 0.045). In conclusion, 11C-Methionine and 68Ga-Pentixafor PET/CT demonstrate higher sensitivity than 18F-FDG PET/CT in detecting BM involvement in SMM.