Comparison of the diagnostic performance and impact on management of 18F-FDG PET/CT and whole-body MRI in multiple myeloma.

PURPOSE: Comparative data on the impact of imaging on management is lacking for multiple myeloma. This study compared the diagnostic performance and impact on management of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and whole-body magnetic resonance imaging (WBMRI) in treatment-naive myeloma. METHODS: Forty-six patients undergoing 18F-FDG PET/CT and WBMRI were reviewed by a nuclear medicine physician and radiologist, respectively, for the presence of myeloma bone disease. Blinded clinical and imaging data were reviewed by two haematologists in consensus and management recorded following clinical data ± 18F-FDG PET/CT or WBMRI. Bone disease was defined using International Myeloma Working Group (IMWG) criteria and a clinical reference standard. Per-patient sensitivity for lesion detection was established. McNemar test compared management based on clinical assessment ± 18F-FDG PET/CT or WBMRI. RESULTS: Sensitivity for bone lesions was 69.6% (32/46) for 18F-FDG PET/CT (54.3% (25/46) for PET component alone) and 91.3% (42/46) for WBMRI. 27/46 (58.7%) of cases were concordant. In 19/46 patients (41.3%) WBMRI detected more focal bone lesions than 18F-FDG PET/CT. Based on clinical data alone, 32/46 (69.6%) patients would have been treated. Addition of 18F-FDG PET/CT to clinical data increased this to 40/46 (87.0%) patients (p = 0.02); and WBMRI to clinical data to 43/46 (93.5%) patients (p = 0.002). The difference in treatment decisions was not statistically significant between 18F-FDG PET/CT and WBMRI (p = 0.08). CONCLUSION: Compared to 18F-FDG PET/CT, WBMRI had a higher per patient sensitivity for bone disease. However, treatment decisions were not statistically different and either modality would be appropriate in initial staging, depending on local availability and expertise.

Added Value of Contrast-Enhanced T1-Weighted and Diffusion-Weighted Sequences for Characterization of Incidental Findings on Whole Body Magnetic Resonance Imaging in Plasma-Cell Disorders.

BACKGROUND: Whole body magnetic resonance imaging (WBMRI) is currently recommended by guidelines for the assessment of myeloma. This will inevitably result in incidental findings. We aimed to assess the frequency of extraskeletal incidental findings and the added value of contrast-enhanced (CE) T1-weighted (T1-W) and diffusion-weighted (DWI) sequences for their characterization in a single WBMRI examination. PATIENTS AND METHODS: We performed 1.5 T WBMRI in 100 patients (53 female; median age, 65 years) with plasma-cell disorders from January 2014 to July 2017. T2-weighted sequences were reviewed initially for incidental findings, followed by sequential review of T1-W, CE T1-W, and DWI sequences for lesion characterization. Descriptive statistics were undertaken. RESULTS: A total of 348 incidental findings were detected in 97 (97%) of 100 patients; only 38 (10.9%) of 348 findings were indeterminate. T1-W sequences increased diagnostic confidence in the characterization of 12 (31.6%) of 38; CE T1-W sequences in the characterization of 16 (50%) of 32; and DWI increased diagnostic confidence in 21 (55.3%) of 38 compared to the T2-weighted sequence alone. CONCLUSION: Incidental findings are common, but the majority are of no clinical consequence. No additional cancers were noted in our series. DWI and CE T1-W sequences increased diagnostic confidence in 50% of indeterminate findings and may reduce the need for further investigation.

National survey of imaging practice for suspected or confirmed plasma cell malignancies.

OBJECTIVE:: Cross-sectional imaging is now recommended by the National Institute for Health and Care Excellence (NICE) for patients with suspected and newly diagnosed myeloma instead of skeletal survey. The objectives of this study were: (1) To evaluate compliance of current UK imaging practice with reference to National Institute for Health and Care Excellence best-practice clinical guidelines for plasma cell malignancies. (2) To identify factors which may influence diagnostic imaging choices. METHODS:: We conducted a national online survey to assess compliance with guidelines and to identify challenges to implementation (endorsed by Myeloma UK, UK Myeloma Forum and the British Society of Skeletal Radiologists). RESULTS:: Responses were received from 31 district general and 28 teaching hospitals. For suspected and confirmed myeloma, skeletal survey remained the most frequent first-line imaging test (suspected myeloma 44.3%, confirmed myeloma 37.7%). Only 9.8 % of responders offered first-line whole body MRI. CONCLUSION:: Significant challenges remain to standardisation of imaging practice in accordance with national best-practice guidelines. ADVANCES IN KNOWLEDGE:: This is the first publication to date evaluating current UK imaging practice for assessing myeloma since the publication of new guidelines recommending use of advanced cross-sectional imaging techniques. Skeletal survey remains the most commonly performed first-line imaging test in patients with suspected or confirmed myeloma and this is largely due to resource limitations within radiology departments.

The value of semiquantitative analysis in identifying diffuse bone marrow involvement in follicular lymphoma.

AIM: The aim of the study was to investigate the value of fluorine-18-fluorodeoxyglucose ((18)F-FDG)-PET/computed tomography (CT) in identifying diffuse bone marrow (BM) involvement in follicular lymphoma using semiquantitative assessment. METHODS: This is a retrospective analysis of 41 patients with grade 1-3a follicular lymphoma who underwent (18)F-FDG-PET/CT, contrast-enhanced CT and bone marrow trephine biopsy (BMB) as part of staging. BM involvement on PET/CT was assessed by visual and semiquantitative analysis. Standardized uptake values (SUVmax) were measured at the sternum, at both iliac blades and at the T12 vertebra. An average of these four measurements was recorded as SUVav. The single highest overall SUVmax for the four bone sites, the SUVav and the ratios SUVav/mediastinal blood pool (MBP) and SUVav/liver were compared with the BMB result. RESULTS: Focal bone uptake was identified on (18)F-FDG-PET/CT by visual analysis in six patients, including two cases in which the BMB was negative. Assessment of diffuse BM involvement on (18)F-FDG-PET/CT by visual analysis had a sensitivity and specificity of 31 and 92%, respectively. Semiquantitative analysis resulted in an improved sensitivity and specificity of 58 and 96%, respectively, when using SUVav greater than or equal to 2 as the cutoff. Using the ratio SUVav/MBP greater than or equal to 1 the sensitivity of (18)F-FDG-PET/CT to detect BM involvement improved to 83%. CONCLUSION: Visual analysis is useful in determining focal bone involvement, whereas semiquantitative analysis using SUVav/MBP has a high sensitivity and specificity for predicting BM involvement in patients lacking focal bone lesions.