State-of-the-art of bone marrow imaging in multiple myeloma

Review of diffusion-weighted imaging and dynamic contrast-enhanced MRI for multiple myeloma and its precursors (monoclonal gammopathy of undetermined significance and smouldering myeloma)

The last decades, increasing research has been conducted on dynamic contrast-enhanced and diffusion-weighted MRI techniques in multiple myeloma and its precursors. Apart from anatomical sequences which are prone to interpretation errors due to anatomical variants, other pathologies and subjective evaluation of signal intensities, dynamic contrast-enhanced and diffusion-weighted MRI provide additional information on microenvironmental changes in bone marrow and are helpful in the diagnosis, staging and follow-up of plasma cell dyscrasias. Diffusion-weighted imaging provides information on diffusion (restriction) of water molecules in bone marrow and in malignant infiltration. Qualitative evaluation by visually assessing images with different diffusion sensitising gradients and quantitative evaluation of the apparent diffusion coefficient are studied extensively. Dynamic contrast-enhanced imaging provides information on bone marrow vascularisation, perfusion, capillary resistance, vascular permeability and interstitial space, which are systematically altered in different disease stages and can be evaluated in a qualitative and a (semi-)quantitative manner. Both diffusion restriction and abnormal dynamic contrast-enhanced MRI parameters are early biomarkers of malignancy or disease progression in focal lesions or in regions with diffuse abnormal signal intensities. The added value for both techniques lies in better detection and/or characterisation of abnormal bone marrow otherwise missed or misdiagnosed on anatomical MRI sequences. Increased detection rates of focal lesions or diffuse bone marrow infiltration upstage patients to higher disease stages, provide earlier access to therapy and slower disease progression and allow closer monitoring of high-risk patients. Despite promising results, variations in imaging protocols, scanner types and post-processing methods are large, thus hampering universal applicability and reproducibility of quantitative imaging parameters. The myeloma response assessment and diagnosis system and the international myeloma working group provide a systematic multicentre approach on imaging and propose which parameters to use in multiple myeloma and its precursors in an attempt to overcome the pitfalls of dynamic contrast-enhanced and diffusion-weighted imaging.Single sentence summary statementDiffusion-weighted imaging and dynamic contrast-enhanced MRI provide important additional information to standard anatomical MRI techniques for diagnosis, staging and follow-up of patients with plasma cell dyscrasias, although some precautions should be taken on standardisation of imaging protocols to improve reproducibility and application in multiple centres.

The Critical Role of Imaging in the Management of Multiple Myeloma

Multiple myeloma (MM) is characterized by abnormal proliferation of plasma cells in the bone marrow leading to symptoms of anemia, renal failure, hypercalcemia, and bone lesions. Bone imaging is critical for the diagnosis, staging, assessment for the presence and extent of bone lesions, and initial treatment of MM. Skeletal survey is the preferred initial imaging modality due to its availability and low cost. However, it has poor sensitivity and patients with occult myeloma may escape detection, delaying their diagnosis and treatment. New cross-sectional imaging modalities such as low-dose whole body CT, MRI, and PET-CT have high sensitivity and specificity for detecting lytic lesions and extramedullary relapse in MM. The combined use of cross-sectional imaging may provide complimentary information for staging, prognosis, and disease monitoring. In this review, we will discuss commonly used imaging modalities and their advantages and disadvantages in the management of MM.

Diagnostic value of whole-body ultra-low dose computed tomography in comparison with spinal magnetic resonance imaging in the assessment of disease in multiple myeloma

This study compared the diagnostic value of Whole-Body Ultra Low-Dose computed tomography (WBULDCT) with that of Spinal Magnetic Resonance Imaging (SMRI) in identification of spinal bone marrow involvement in patients with Multiple Myeloma (MM). Thirty-five patients with histologically proven MM underwent WBULDCT and dedicated SMRI. Unenhanced WBULDCT was performed on a 256-slice scanner, with 120 kV and 40 mAs. SMRI was performed on a 1·5T magnet, with T1-turbo spin echo and T2-short tau inversion recovery sequences on sagittal plane. WBULDCT was compared with SMRI in terms of lesion detection, pattern and bone marrow involvement. The overall concordance between WBULDCT and SMRI in lesion detection was 76·7%, detecting (25/35) or excluding (8/35) involvement of the axial skeleton, while in 2/35 patients WBULDCT and SMRI were discordant in terms of axial skeleton involvement. The concordance in spinal distribution of lesions was 61·6% on cervical, 71·5% on dorsal, 86·4% on lumbar and 94·4% on sacral, while for the pattern of disease, it was 56·1% for the focal and 88·7% for the combined pattern. Cohen's kappa index was 0·85 (P < 0·001) assessing an excellent agreement. WBULDCT represents a useful diagnostic tool in the detection of spinal involvement of MM patients, offering detailed information about extra-axial involvement, which could be potentially missed with dedicated SMRI.