Molecular imaging in myeloma precursor disease

Current Status and Future of Artificial Intelligence in MM Imaging: A Systematic Review

Artificial intelligence (AI) has attracted increasing attention as a tool for the detection and management of several medical conditions. Multiple myeloma (MM), a malignancy characterized by uncontrolled proliferation of plasma cells, is one of the most common hematologic malignancies, which relies on imaging for diagnosis and management. We aimed to review the current literature and trends in AI research of MM imaging. This study was performed according to the PRISMA guidelines. Three main concepts were used in the search algorithm, including "artificial intelligence" in "radiologic examinations" of patients with "multiple myeloma". The algorithm was used to search the PubMed, Embase, and Web of Science databases. Articles were screened based on the inclusion and exclusion criteria. In the end, we used the checklist for Artificial Intelligence in Medical Imaging (CLAIM) criteria to evaluate the manuscripts. We provided the percentage of studies that were compliant with each criterion as a measure of the quality of AI research on MM. The initial search yielded 977 results. After reviewing them, 14 final studies were selected. The studies used a wide array of imaging modalities. Radiomics analysis and segmentation tasks were the most popular studies (10/14 studies). The common purposes of radiomics studies included the differentiation of MM bone lesions from other lesions and the prediction of relapse. The goal of the segmentation studies was to develop algorithms for the automatic segmentation of important structures in MM. Dice score was the most common assessment tool in segmentation studies, which ranged from 0.80 to 0.97. These studies show that imaging is a valuable data source for medical AI models and plays an even greater role in the management of MM.

Whole-body diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient values as prognostic factors in multiple myeloma

Multiple myeloma (MM) is a neoplasm of the B lymphocytes characterized by the uncontrolled proliferation of a plasmocyte clone. Magnetic resonance imaging (MRI) remains the most sensitive and specific imaging method for the detection of bone marrow infiltration, before macroscopic bone changes are visible, with evidence that the detection rate and overall performance of MRI could be enhanced by applying diffusion-weighted imaging (DWI). The aim of our research was to evaluate whether measuring apparent diffusion coefficient (ADC) values in newly diagnosed patients with MM could be a prognostic factor for the course of the disease and to ascertain whether there is any correlation with other prognostic factors in MM. A retrospective study was performed on a group of 32 patients with newly diagnosed MM that underwent at least two whole-body (WB)-MRIs; one before and one after induction therapy. Patients with advanced stage of disease showed an increased ADC value: Stage 2 vs. stage 1 (1.162 vs. 0.289, P=0.033), respectively, stage 3 vs. stage 1 (0.867 vs. 0.289, P=0.041). In addition, ADC values were inversely correlated with survival time: r=-0.641, P<0.001. According to the multivariate linear regression model, we observed that for every point of ADC value (before treatment) the survival was decreased/reduced by 14.5 months. Moreover, bortezomib therapy predicted an increase in the survival length/duration by 7.9 months. Our regression equation proved to be a good fit for the model, explaining 57.8% of survival duration (adjusted R²=0.578). In conclusion, the negative prognostic factors associated with WB-MRI are represented by high ADC values before treatment (for every point of ADC the survival was decreased by 14.5 months) and focal/diffuse marrow involvement.

Diagnostic performance of 18 F-FDG-PET/CT compared to standard skeletal survey for detecting bone destruction in smouldering multiple myeloma: time to move forward

Skeletal survey (SS) continues to be used in the community to detect bone disease in patients with multiple myeloma (MM). While the false-negative rate is high, the specificity of SS is less well characterised. Here, we compare the diagnostic accuracy of SS compared to ¹⁸ F-FDG-PET/CT (positron emission tomography/computed tomography) in 79 patients referred to our tertiary centre with a diagnosis of smouldering MM. SS had a specificity of 83·1% (95% confidence interval: 72·0-90·5%). This study reinforces the importance of using more specific imaging techniques to avoid inaccurate diagnosis that could lead to the risks associated with unnecessary therapy in patients with smouldering MM.

Differential diagnostic value of 18F-FDG PET/CT in osteolytic lesions

Background

Both bone metastases and multiple myeloma (MM) are malignant diseases that can appear osteolytic on imaging and are difficult to differentiate. While positron emission tomography/computed tomography (PET/CT) has been demonstrated useful for the diagnosis of various bone lesions, correlations between PET/CT and histopathology and these diseases are unclear. This retrospective study investigated the optimal cutoff standardized uptake value (SUV) to differentiate MM and bone metastasis.

Methods

Patients with newly diagnosed osteolytic lesions (n = 344) and suspected malignancy underwent both fluorodeoxyglucose (FDG) PET/CT and biopsy/surgery. FDG uptake and morphologic changes (e.g., soft tissue mass formation) were compared with pathological results.

Results

A total of 8896 osteolytic lesions were evaluated. The SUVmax of MM osteolytic lesions (1.6 ± 0.7) was significantly lower than that of bone metastases (5.5 ± 2.7; p = 0.000). The best cutoff SUVmax for differentiating MM and bone metastasis was 2.65 (sensitivity 86.1%, specificity 94.7%; p = 0.000). The SUVmax of bone lesions of soft tissue mass was higher than that for pure osteolytic lesions (p = 0.000). A greater percentage of patients with bone metastasis had a soft tissue mass (7%) than did patients with MM (2%). The mean SUVmax of bone metastases was 5.5 ± 2.7 (0.4-30.4); that of primary tumors was 7.5 ± 4.2 (1.0-28.5). The SUVmax of bone metastases significantly correlated with the SUVmax of primary tumors (r = 0.532; p = 0.000).

Conclusions

FDG PET/CT is a valuable tool to differentiate osteolytic lesions. The best cutoff value of SUVmax for differentiating MM from bone metastasis is 2.65. The significant correlation between the SUVmax of bone metastasis and that of primary tumors is helpful for detecting primary tumors.

Whole-body MRI, dynamic contrast-enhanced MRI, and diffusion-weighted imaging for the staging of multiple myeloma

Magnetic resonance imaging (MRI) is the most sensitive imaging technique for the detection of bone marrow infiltration, and has therefore recently been included in the new diagnostic myeloma criteria, as proposed by the International Myeloma Working Group. Nevertheless, conventional MRI only provides anatomical information and is therefore only of limited use in the response assessment of patients with multiple myeloma. The additional information from functional MRI techniques, such as diffusion-weighted imaging and dynamic contrast-enhanced MRI, can improve the detection rate of bone marrow infiltration and the assessment of response. This can further enhance the sensitivity and specificity of MRI in the staging of multiple myeloma patients. This article provides an overview of the technical aspects of conventional and functional MRI techniques with practical recommendations. It reviews the diagnostic performance, prognostic value, and role in therapy assessment in multiple myeloma and its precursor stages.

MRI in multiple myeloma: a pictorial review of diagnostic and post-treatment findings

Magnetic resonance imaging (MRI) is increasingly being used in the diagnostic work-up of patients with multiple myeloma. Since 2014, MRI findings are included in the new diagnostic criteria proposed by the International Myeloma Working Group. Patients with smouldering myeloma presenting with more than one unequivocal focal lesion in the bone marrow on MRI are considered having symptomatic myeloma requiring treatment, regardless of the presence of lytic bone lesions. However, bone marrow evaluation with MRI offers more than only morphological information regarding the detection of focal lesions in patients with MM. The overall performance of MRI is enhanced by applying dynamic contrast-enhanced MRI and diffusion weighted imaging sequences, providing additional functional information on bone marrow vascularization and cellularity.

This pictorial review provides an overview of the most important imaging findings in patients with monoclonal gammopathy of undetermined significance, smouldering myeloma and multiple myeloma, by performing a ‘total’ MRI investigation with implications for the diagnosis, staging and response assessment.

Main message

• Conventional MRI diagnoses multiple myeloma by assessing the infiltration pattern.

• Dynamic contrast-enhanced MRI diagnoses multiple myeloma by assessing vascularization and perfusion.

• Diffusion weighted imaging evaluates bone marrow composition and cellularity in multiple myeloma.

• Combined morphological and functional MRI provides optimal bone marrow assessment for staging.

• Combined morphological and functional MRI is of considerable value in treatment follow-up.

A voluminous mass as an initial clinical symptom of multiple myeloma: A case report

Extramedullary multiple myeloma (EMM) is a type of multiple myeloma (MM) that is defined by the presence of extraskeletal (soft tissue or visceral) clonal plasma cell infiltrates, which may be present at the time of initial diagnosis or at the time of relapse. Although extramedullary lesions may be present with other clinical features at the time of diagnosis, the onset of a solid formation as a first clinical symptom of MM is unusual. The present study reports the case of a 77-year-old male who was admitted to the Hematology Unit of the National Cancer Research Center, Istituto Tumori 'Giovanni Paolo II' (Bari, Italy) with a mass protruding from the right side of his lower back. Serum immunofixation revealed positivity for monoclonal protein (M-protein) and Bence Jones proteinuria was positive. In addition, a computed tomography scan of the abdomen, which was confirmed by magnetic resonance imaging, revealed a voluminous solid formation resembling a sarcoma. M-protein is known to be present in numerous diseases encountered in clinical practice, including hematological or other diseases; thus, a Tru-Cut biopsy of the lesion was performed, which revealed an infiltration of plasma cells. In addition, a bone marrow biopsy revealed the presence of 70% plasma cells, and a diagnosis of primary EMM was established. In conclusion, EMM should be included in the differential diagnosis of a mass, particularly in patients where M-protein is detected in the blood and/or urine.

Diagnostic and prognostic utility of non-invasive imaging in diabetes management

Medical imaging technologies are acquiring an increasing relevance to assist clinicians in diagnosis and to guide management and therapeutic treatment of patients, thanks to their non invasive and high resolution properties. Computed tomography, magnetic resonance imaging, and ultrasonography are the most used imaging modalities to provide detailed morphological reconstructions of tissues and organs. In addition, the use of contrast dyes or radionuclide-labeled tracers permits to get functional and quantitative information about tissue physiology and metabolism in normal and disease state. In recent years, the development of multimodal and hydrid imaging techniques is coming to be the new frontier of medical imaging for the possibility to overcome limitations of single modalities and to obtain physiological and pathophysiological measurements within an accurate anatomical framework. Moreover, the employment of molecular probes, such as ligands or antibodies, allows a selective in vivo targeting of biomolecules involved in specific cellular processes, so expanding the potentialities of imaging techniques for clinical and research applications. This review is aimed to give a survey of characteristics of main diagnostic non-invasive imaging techniques. Current clinical appliances and future perspectives of imaging in the diagnostic and prognostic assessment of diabetic complications affecting different organ systems will be particularly addressed.

Understanding biology to tackle the disease: Multiple myeloma from bench to bedside, and back

Multiple myeloma (MM) is a cancer of antibody-producing plasma cells. The pathognomonic laboratory finding is a monoclonal immunoglobulin or free light chain in the serum and/or urine in association with bone marrow infiltration by malignant plasma cells. MM develops from a premalignant condition, monoclonal gammopathy of undetermined significance (MGUS), often via an intermediate stage termed smoldering multiple myeloma (SMM), which differs from active myeloma by the absence of disease-related end-organ damage. Unlike MGUS and SMM, active MM requires therapy. Over the past 6 decades, major advancements in the care of MM patients have occurred, in particular, the introduction of novel agents (ie, proteasome inhibitors, immunomodulatory agents) and the implementation of hematopoietic stem cell transplantation in suitable candidates. The effectiveness and good tolerability of novel agents allowed for their combined use in induction, consolidation, and maintenance therapy, resulting in deeper and more sustained clinical response and extended progression-free and overall survival. Previously a rapidly lethal cancer with few therapeutic options, MM is the hematologic cancer with the most novel US Food and Drug Administration-approved drugs in the past 15 years. These advances have resulted in more frequent long-term remissions, transforming MM into a chronic illness for many patients.

Dynamic contrast-enhanced magnetic resonance imaging for assessment of antiangiogenic treatment effects in multiple myeloma

PURPOSE

To noninvasively assess bone marrow microcirculation before and after therapy in patients with newly diagnosed multiple myeloma with dynamic contrast-enhanced MRI (DCE-MRI).

EXPERIMENTAL DESIGN

Ninety-six patients received DCE-MRI before and after primary treatment for newly diagnosed multiple myeloma. For the 91 evaluable patients, treatment consisted of high-dose therapy (HDT) with autologous stem cell transplantation (ASCT) in 82 patients and chemotherapy without ASCT in 9 patients. In addition, 33 healthy volunteers were imaged as the control group. Analysis of DCE-MRI was performed according to the two-compartment model by Brix to quantify amplitude A (associated with blood volume) and exchange rate constant kep (reflecting vessel permeability and perfusion).

RESULTS

Nonresponders showed significantly higher A-values before the start of therapy compared with responders (P = 0.02). In both responders and nonresponders to therapy, A-values dropped significantly (P = 0.004 and <0.001, respectively) after primary therapy, whereas lower values for kep were found only in responders (P < 0.001). Depth of remission was significantly correlated to decreased bone marrow microcirculation: Patients in near complete response (nCR) or complete remission (CR) after treatment showed significantly lower values for A compared with patients not achieving nCR+CR. The application of HDT or novel agents had no significant effect on DCE-MRI parameters after therapy, although patients treated with novel agents more often achieved nCR+CR (42%/12.5%; P < 0.002). Higher kep-values at second MRI were positively correlated to shorter overall survival (HR 3.53; 95% confidence intervals, 1.21-10.33; P = 0.02).

CONCLUSION

Parameters from DCE-MRI are correlated to remission after primary therapy and outcome in newly diagnosed multiple myeloma.

[Use of whole-body diffusion-weighted magnetic resonance imaging for the diagnosis of and therapeutic response in multiple myeloma]

INTRODUCTION

Multiple myeloma is an incurable neoplastic disorder of B cells characterized by diffuse bone marrow infiltration, circumscribed bone lesions, and soft-tissue spreading. The role of novel functional imaging techniques in multiple myeloma includes initial staging of the disease, detection and characterization of complications, and evaluation of the response to treatment.

AIM

The authors present their 2 and a half-year experience with diffusion-weighted magnetic resonance imaging in staging and follow up of patients with multiple myeloma.

METHOD

Conventional T1 weighted, T2 weighted fat suppressed and 2 b-values diffusion-weighted sequences were performed from skull base to symphysis in 27 patients suspected to have multiple myeloma. Apparent diffusion coefficient calculation was carried out in 3 cases. The final diagnosis of multiple myeloma was verified by bone-marrow biopsy.

RESULTS

In 13 cases magnetic resonance imaging revealed the suspected disease. In one patient magnetic resonance imaging failed to detect the disease because of metallic artifacts. In 6 cases diffusion-weighted sequences showed additional information about bone-marrow infiltration.

CONCLUSIONS

Diffusion-weighted magnetic resonance imaging with conventional sequences is a useful and promising functional imaging modality in the early diagnosis of myeloma multiple.

Smoldering multiple myeloma: present position and potential promises

Since smoldering multiple myeloma (SMM) was first described over three decades ago based on a case series of six patients, its definition and our understanding of the entity have evolved considerably. The risk of progression to symptomatic myeloma (MM) varies greatly among individuals diagnosed with myeloma precursor disease. Epidemiologic, molecular, flow cytometric and radiological techniques have demonstrated that this transformation to MM from precursor states is not sudden but rather a continuous overlapping series of events with evidence of end-organ damage that could manifest in the earliest stages of disease. Contemporary antimyeloma therapies can yield rapid, deep, and durable responses with manageable toxicities, and molecular-cell-based measures are now available to rule out minimal residual disease. With this information, clinical studies with correlative measures can now be developed to test the fundamental hypothesis that intervention in early myeloma may provide a measurable clinical benefit to patients by either delaying progression or eradicating plasma cell clones.

Differential diagnosis of monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic plasma cell disorder occurring in 4.2% of adults > 50 years of age, which can progress into symptomatic diseases either through proliferation of the plasma cell clone, giving rise to multiple myeloma and other lymphoplasmacellular neoplasms, or through organ damage caused by the monoclonal protein, as seen in light-chain amyloidosis and related conditions. Differential diagnosis of asymptomatic and symptomatic monoclonal gammopathies is the determinant for starting therapy. The criteria for determining end-organ damage should include markers of organ injury caused by the monoclonal protein. Patient assessment and optimal follow-up are now performed using risk stratification models that should also take into account the risk of developing AL amyloidosis. Patients with low-risk MGUS (approximately 40% of all MGUS patients) need limited assessment and very infrequent follow-up. The ongoing development of novel molecular biomarkers and advanced imaging techniques will improve the identification of high-risk patients who may benefit from early therapeutic intervention through innovative clinical trials.

Does my patient with a serum monoclonal spike have multiple myeloma?

A monoclonal spike on serum protein electrophoresis is a frequent finding in the general population and pathognomonic of a plasma cell dyscrasia. In otherwise healthy individuals, it is diagnostic of two asymptomatic, premalignant conditions called monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) which carry a lifelong risk of progression to multiple myeloma (MM) or related malignancy. This article discusses the criteria for diagnosis of MGUS, SMM, and MM; current recommendations for follow-up and risk factors for progression to MM of patients with MGUS and SMM; and diagnostic evaluation of suspected MM transformation.