Imaging for Plasma Cell Dyscrasias: What, When, and How?

Abstract

Imaging plays a vital role in the diagnosis, response assessment, and follow-up of patients with plasma cell bone disease. The radiologic diagnostic paradigm has thus far evolved with developing technology and availability of better imaging platforms; however, the skewed availability of these imaging modalities in developed vis-à-vis the developing countries along with the lack of uniformity in reporting has led to a consensus on the imaging criteria for diagnosing and response assessment in plasma cell dyscrasia. Therefore, it is imperative for not only the radiologists but also the treating oncologist to be aware of the criteria and appropriate imaging modality to be used in accordance with the clinical question. The review will allow the treating oncologist to answer the following questions on the diagnostic, prognostic, and predictive abilities of various imaging modalities for plasma cell dyscrasia: a) What lesions can look like multiple myeloma (MM) but are not?; b) Does the patient have MM? To diagnose MM in a high-risk SMM patient with clinical suspicion, which modality should be used and why?; c) Is the patient responding to therapy on follow-up imaging once treatment is initiated?; d) To interpret commonly seen complications post-therapy, when is it a disease and when is the expected sequel to treatment? Fractures, red marrow reconversion?; and e) When is the appropriate time to flag a patient for further workup when interpreting MRI spine done for back pain in the elderly? How do we differentiate between commonly seen osteoporosis-related degenerative spine versus marrow infiltrative disorder?

Imaging Recommendations for Diagnosis, Staging, and Management of Hematological Malignancies

“…Plasma cell disorders range from the spectrum of the mostly benign monoclonal gammopathy of unknown significance to the intermediate smoldering multiple myeloma to the frankly malignant MM. 19 Imaging of bone lesions forms a major stay in the diagnosis and management of MM. The CRAB criteria: Hyper c alcemia, R enal insufficiency, A naemia and B one lesions—at least one or more bone lesions on X-Ray/CT/PET-CT—form the four pillars upon which a diagnosis is made in patients with clonal bone marrow plasma cells more than 10%.…”

“…The CRAB criteria: Hyper c alcemia, R enal insufficiency, A naemia and B one lesions—at least one or more bone lesions on X-Ray/CT/PET-CT—form the four pillars upon which a diagnosis is made in patients with clonal bone marrow plasma cells more than 10%. 19…”

“…The CRAB criteria: Hypercalcemia, Renal insufficiency, Anaemia and Bone lesions-at least one or more bone lesions on X-Ray/CT/PET-CT-form the four pillars upon which a diagnosis is made in patients with clonal bone marrow plasma cells more than 10%. 19 At least one well-defined lytic lesion of diameter greater than 5mm is necessary to satisfy the bony lesion category of CRAB lesions. 4 Advances in cross-sectional imaging have led the IMWG to form newer guidelines with the definition of myeloma-defining events) in which at least two or more focal lesions in the marrow of size greater than 5 mm can be used to make the diagnosis, in the absence of focal lytic lesions on X-ray or CT. 4 Newer advanced sequences like diffusionweighted imaging with background suppression (DWIBS) have also helped to increase sensitivity and specificity of bony lesion detection; however, their inclusion into a formal role as defining criteria is awaited pending further research.…”