The role of anatomic and functional staging in myeloma: description of Durie/Salmon plus staging system

CXCR4-Targeted PET Imaging in Hematologic Malignancies: A Systematic Review and Meta-analysis

PURPOSE

The aims of this study were to perform a comprehensive review and meta-analyses and to report pooled diagnostic results on CXCR4-targeted PET, particularly considering detection, visualization, and prognostication.

PATIENTS AND METHODS

This study followed PRISMA-DTA. A systematic search was conducted on major medical literature databases up to March 1, 2024. The search strategy was designed to include CXCR4 PET studies in hematologic malignancies. A random-effects model combined sensitivity values derived from 2-by-2 contingency tables. Pooled means for SUV max were computed. Analyses were performed by R software.

RESULTS

The initial search resulted in a total of 1428 studies. Ultimately, 18 were eligible for systematic review and meta-analytic calculations. Twelve studies (320 patients) included B-cell lymphoma. The pooled detection rate of CXCR4 PET was 99.4% (95% confidence interval [CI]: 88.3%-100%). Marginal zone lymphoma was investigated in 5 studies (209 patients), with a pooled sensitivity of 97.6% (95% CI: 79.7%-99.8%). In studies on central nervous system lymphoma, CXCR4 PET demonstrated 100% accuracy at both patient and lesion levels. Also, it demonstrated a significantly higher tumor-to-background ratio than 18 F-FDG PET. For multiple myeloma, 5 studies (116 patients) showed a patient-level pooled sensitivity of 77.8% (95% CI: 64.4%-87.2%), whereas 18 F-FDG PET had 65.0% (95% CI: 55.2%-73.7%). The pooled SUV max for CXCR4 PET was 13.6 (95% CI: 9.3-17.8) versus 9.0 (95% CI: 6.3-11.7) for 18 F-FDG PET. Additionally, CXCR4 PET-derived parameters were significant predictors of survival in multiple myeloma.

CONCLUSIONS

CXCR4 PET can be a helpful imaging tool for evaluating hematologic malignancies, particularly in B-cell lymphoma and multiple myeloma patients. In specific clinical scenarios, it appears to be superior compared with the current standard-of-care imaging.

Role of Novel Quantitative Imaging Techniques in Hematological Malignancies

Hematological malignancies exhibit a widespread distribution, necessitating evaluation of disease activity over the entire body. In clinical practice, visual analysis and semiquantitative parameters are used to assess 18F-FDGPET/CT imaging, which solely represents measurements of disease activity from limited area and may not adequately reflect global disease assessment. An efficient method for assessing the global disease burden of hematological malignancies is to employ PET/computed tomography based novel quantitative parameters. In this article, we explored novel quantitative parameters on PET/CT imaging for assessing global disease burden and the potential role of artificial intelligence (AI) to determine these parameters in evaluation of hematological malignancies.

Coefficient of variation and texture analysis of 18F-FDG PET/CT images for the prediction of outcome in patients with multiple myeloma

In multiple myeloma (MM) bone marrow infiltration by monoclonal plasma cells can occur in both focal and diffuse manner, making staging and prognosis rather difficult. The aim of our study was to test whether texture analysis of 18 F-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) images can predict survival in MM patients. Forty-six patients underwent 18 F-FDG-PET/CT before treatment. We used an automated contouring program for segmenting the hottest focal lesion (FL) and a lumbar vertebra for assessing diffuse bone marrow involvement (DI). Maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean) and texture features such as Coefficient of variation (CoV), were obtained from 46 FL and 46 DI. After a mean follow-up of 51 months, 24 patients died of myeloma and were compared to the 22 survivors. At univariate analysis, FL SUVmax (p = 0.0453), FL SUVmean (p = 0.0463), FL CoV (p = 0.0211) and DI SUVmax (p = 0.0538) predicted overall survival (OS). At multivariate analysis only FL CoV and DI SUVmax were retained in the model (p = 0.0154). By Kaplan-Meier method and log-rank testing, patients with FL CoV below the cut-off had significantly better OS than those with FL CoV above the cut-off (p = 0.0003), as well as patients with DI SUVmax below the threshold versus those with DI SUVmax above the threshold (p = 0.0006). Combining FL CoV and DI SUVmax by using their respective cut-off values, a statistically significant difference was found between the resulting four survival curves (p = 0.0001). Indeed, patients with both FL CoV and DI SUVmax below their respective cut-off values showed the best prognosis. Conventional and texture parameters derived from 18F-FDG PET/CT analysis can predict survival in MM patients by assessing the heterogeneity and aggressiveness of both focal and diffuse infiltration.

Metabolomic biomarkers of multiple myeloma: A systematic review

Multiple myeloma (MM) is an incurable malignancy of clonal plasma cells. Various diagnostic methods are used in parallel to accurately determine stage and severity of the disease. Identifying a biomarker or a panel of biomarkers could enhance the quality of medical care that patients receive by adopting a more personalized approach. Metabolomics utilizes high-throughput analytical platforms to examine the levels and quantities of biochemical compounds in biosamples. The aim of this review was to conduct a systematic literature search for potential metabolic biomarkers that may aid in the diagnosis and prognosis of MM. The review was conducted in accordance with PRISMA recommendations and was registered in PROSPERO. The systematic search was performed in PubMed, CINAHL, SciFinder, Scopus, The Cochrane Library and Google Scholar. Studies were limited to those involving people with clinically diagnosed MM and healthy controls as comparators. Articles had to be published in English and had no restrictions on publication date or sample type. The quality of articles was assessed according to QUADOMICS criteria. A total of 709 articles were collected during the literature search. Of these, 436 were excluded based on their abstract, with 26 more removed after a thorough review of the full text. Finally, 16 articles were deemed relevant and were subjected to further analysis of their data. A number of promising candidate biomarkers was discovered. Follow-up studies with large sample sizes are needed to determine their suitability for clinical applications.

Recent advances in imaging and artificial intelligence (AI) for quantitative assessment of multiple myeloma

Multiple myeloma (MM) is a malignant blood disease, but there have been significant improvements in the prognosis due to advancements in quantitative assessment and targeted therapy in recent years. The quantitative assessment of MM bone marrow infiltration and prognosis prediction is influenced by imaging and artificial intelligence (AI) quantitative parameters. At present, the primary imaging methods include computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). These methods are now crucial for diagnosing MM and evaluating myeloma cell infiltration, extramedullary disease, treatment effectiveness, and prognosis. Furthermore, the utilization of AI, specifically incorporating machine learning and radiomics, shows great potential in the field of diagnosing MM and distinguishing between MM and lytic metastases. This review discusses the advancements in imaging methods, including CT, MRI, and PET/CT, as well as AI for quantitatively assessing MM. We have summarized the key concepts, advantages, limitations, and diagnostic performance of each technology. Finally, we discussed the challenges related to clinical implementation and presented our views on advancing this field, with the aim of providing guidance for future research.

Quantitative Analysis of Whole-Body MRI for Accessing the Degree of Diffuse Infiltration Patterns and Identifying High Risk Cases of Newly Diagnosed Multiple Myeloma

BACKGROUND

Accurate identification of high-risk multiple myeloma (HRMM) is important for prognostication. The degree of diffuse infiltration patterns on magnetic resonance imaging (MRI) is associated with patient prognosis in multiple myeloma. However, objective indexes to determine the degree of diffuse infiltration patterns are unavailable.

PURPOSE

To investigate whether qualitative and quantitative evaluations of diffuse infiltration patterns on MRI could identify HRMM.

STUDY TYPE

Retrospective.

SUBJECTS

Totally, 180 patients (79 HRMM and 101 standard-risk MM) were assessed. The presence of del(17p), t(4;14), t(14;16), t(14;20), gain 1q, and/or p53 mutations was considered to indicate HRMM.

FIELD STRENGTH/SEQUENCE

3.0 T/diffusion-weighted whole-body imaging with background body signal suppression (DWIBS), modified Dixon chemical-shift imaging Quant (mDIXON Quant), and short TI inversion recovery (STIR).

ASSESSMENT

Qualitative analysis involved assessing the degree of diffuse marrow infiltration (mild, moderate, or severe), and quantitative analysis involved evaluating apparent diffusion coefficient (ADC), fat fraction (FF), and T2* values. Clinical data such as sex, age, hemoglobin, serum albumin, serum calcium, serum creatinine, serum lactate dehydrogenase, β2-microglobulin, and bone marrow plasma cells (BMPCs) were also included.

STATISTICAL TESTS

Univariate and multivariate analyses, receiver operating characteristic (ROC) curve. P < 0.05 was considered statistically significant.

RESULTS

The high-risk group had significantly higher ADC and T2* and lower FF compared with the standard-risk group. Multivariate analysis indicated BMPCs as a significant independent risk factor for HRMM (odds ratio (OR) = 1.019, 95% CI 1.004-1.033), while FF was a significant independent protective factor associated with HRMM (OR = 0.972, 95% CI 0.946-0.999). The combination of BMPCs and FF achieved the highest areas under the curve (AUC) of 0.732, with sensitivity and specificity of 70.9% and 68.3%, respectively.

DATA CONCLUSION

Compared with qualitative analysis, FF value was independently associated with HRMM. The quantitative features of diffuse marrow infiltration on MRI scans are more effective in detecting HRMM.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

[68Ga]Pentixafor PET/CT for staging and prognostic assessment of newly diagnosed multiple myeloma: comparison to [18F]FDG PET/CT

PURPOSE

To evaluate the prognostic performance of [68Ga]Pentixafor PET/CT at baseline for staging of patients with newly diagnosed multiple myeloma (MM) and to compare it with [18F]FDG PET/CT and the Revised-International Staging System (R-ISS).

METHODS

Patients who underwent [68Ga]Pentixafor and [18F]FDG PET/CT imaging were retrospectively included. Patient staging was performed according to the Durie-Salmon PLUS staging system based on [68Ga]Pentixafor PET/CT and [18F]FDG PET/CT images, and the R-ISS. Progression-free survival (PFS) at patient follow-up was estimated using the Kaplan-Meier estimator and compared using the log-rank test. Area under the receiver operating characteristic curve (AUC) was calculated to assess predictive performance.

RESULTS

Fifty-five MM patients were evaluated. Compared with [18F]FDG PET, [68Ga]Pentixafor PET detected 25 patients as the same stage, while 26 patients were upstaged and 4 patients were downstaged (P = 0.001). After considering the low-dose CT data, there was no statistically significant difference in the number of patients classified in each stage using [68Ga]Pentixafor PET/CT and [18F]FDG PET/CT (P = 0.091). [68Ga]Pentixafor PET/CT-based staging discriminated PFS outcomes in patients with different disease stages (stage I vs. stage II, stage I vs. stage III, and stage II vs. stage III; all P < 0.05), whereas for [18F]FDG PET/CT, there was only a difference in median PFS between stage I and III (P = 0.021). When staged by R-ISS, the median PFS for stage III was significantly lower than that for stage I and II (P = 0.008 and 0.035, respectively). When predicting 2-year PFS based on staging, the AUC of [68Ga]Pentixafor PET/CT was significantly higher than that of [68Ga]Pentixafor PET (0.923 vs. 0.821, P = 0.002), [18F]FDG PET (0.923 vs. 0.752 P = 0.002), and R-ISS (0.923 vs. 0.776, P = 0.005).

CONCLUSIONS

[68Ga]Pentixafor PET/CT-based staging possesses substantial potential to predict disease progression in newly diagnosed MM patients.

Value of third-generation of VNCa dual-energy CT for differentiating diffuse marrow infiltration of multiple myeloma from red bone marrow

This study aims to investigate the ability of bone marrow imaging using third-generation dual-energy computed tomography (CT) virtual noncalcium (VNCa) to differentiate between multiple myeloma (MM) with diffuse bone marrow infiltration and red bone marrow (RBM). Bone marrow aspiration or follow-up results were used as reference. We retrospectively reviewed 188 regions of interests (ROIs) from 21 patients with confirmed MM and diffuse bone marrow infiltrations who underwent VNCa bone marrow imaging between May 2019 and September 2022. At the same time, we obtained 98 ROIs from 11 subjects with RBM for comparative study, and 189 ROIs from 20 subjects with normal yellow bone marrow for the control group. The ROIs were delineated by 2 radiologists independently, the interobservers reproducibility was evaluated by interclass correlation coefficients. The correlation with MRI grade results was analyzed by Spearman correlation coefficient. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal threshold for differentiating between these groups and to assess diagnostic performance. There were statistically significant differences in VNCa CT values of bone marrow among the MM, RBM, and control groups (all P < .001), with values decreasing sequentially. A strong positive rank correlation was observed between normal bone marrow, subgroup MM with moderately and severe bone marrow infiltration divided by MRI and their corresponding CT values (ρ = 0.897, 95%CI: 0.822 to 0.942, P < .001). When the CT value of VNCa bone marrow was 7.15 HU, the area under the curve (AUC) value for differentiating RBM and MM was 0.723, with a sensitivity of 50.5% and a specificity of 89.8%. When distinguishing severe bone marrow infiltration of MM from RBM, the AUC value was 0.80 with a sensitivity 70.9% and a specificity 78.9%. The AUC values for MM, RBM, and the combined group compared to the control group were all >0.99, with all diagnostic sensitivity and specificity exceeding 95%. VNCa bone marrow imaging using third-generation dual-energy CT accurately differentiates MM lesions from normal bone marrow or RBM. It demonstrates superior diagnostic performance in distinguishing RBM from MM with diffuse bone marrow infiltration.

Prognostic significance of extramedullary disease (EMD) detected on pre-transplant 18F-FDG PET/CT in patients with multiple myeloma: Results of PIPET-M trial

Background

It is difficult to prognosticate the post-Autologous Stem Cell Transplant (ASCT) responses in multiple myeloma (MM) with the currently available prognostication models. 18F-FDGPET/CT has numerous advantages to prognosticate the post-transplant responses by assessing extramedullary disease (EMD) in addition to the extent of active disease. We aimed at identifying the prognostic value of EMD in predicting progression-free survival (PFS) and overall survival (OS).

Methods

This is a single centre prospective study from western India during a study period of 2014-2022 (with a median follow-up of patients of 6 years). All ASCT patients underwent 18F-FDG-PET/CT as part of pre-transplant workup. The conditioning and treatment protocols were not modified based on PET/CT findings. EMD on PET/CT was correlated with pre-transplant biochemical markers and post-ASCT survival/ progression (as defined by revised IMWG criteria). Statistical analysis was done using SPSS ver. 20.

Results

Patients with pre-ASCT EMD had a hazard-ratio for post-transplant all-cause mortality of 5.46 (p-0.045). Pre-transplant β2M and LDH were significantly higher in patients with EMD (p-0.036). The 6-year median OS in patients with and without EMD were 57.1%, and 80.6% respectively. Kaplan-Meier analysis showed poorer OS in patients with EMD χ2 (1-0.496, p-0.481). There was no significant difference in clinical or biochemical EFS among patients with EMD.

Conclusion

EMD detected on 18F-FDG-PET/CT has a higher hazard for mortality and is significantly correlated with pre-transplant higher β2M and LDH levels. Thus, EMD by pre-transplant 18F-FDG-PET/CT has a significant prognostic role.

International EANM-SNMMI-ISMRM consensus recommendation for PET/MRI in oncology

PREAMBLE

The Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM) is a professional non-profit medical association that facilitates communication worldwide between individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. The merged International Society for Magnetic Resonance in Medicine (ISMRM) is an international, nonprofit, scientific association whose purpose is to promote communication, research, development, and applications in the field of magnetic resonance in medicine and biology and other related topics and to develop and provide channels and facilities for continuing education in the field.The ISMRM was founded in 1994 through the merger of the Society of Magnetic Resonance in Medicine and the Society of Magnetic Resonance Imaging. SNMMI, ISMRM, and EANM members are physicians, technologists, and scientists specializing in the research and practice of nuclear medicine and/or magnetic resonance imaging. The SNMMI, ISMRM, and EANM will periodically define new guidelines for nuclear medicine practice to help advance the science of nuclear medicine and/or magnetic resonance imaging and to improve the quality of service to patients throughout the world. Existing practice guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each practice guideline, representing a policy statement by the SNMMI/EANM/ISMRM, has undergone a thorough consensus process in which it has been subjected to extensive review. The SNMMI, ISMRM, and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging and magnetic resonance imaging requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline by those entities not providing these services is not authorized. These guidelines are an educational tool designed to assist practitioners in providing appropriate care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, the SNMMI, the ISMRM, and the EANM caution against the use of these guidelines in litigation in which the clinical decisions of a practitioner are called into question. The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by the physician or medical physicist in light of all the circumstances presented. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the guidelines. The practice of medicine includes both the art and the science of the prevention, diagnosis, alleviation, and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment. Therefore, it should be recognized that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources, and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.

Development of a Semiquantitative Whole-Body MRI Scoring System for Multiple Myeloma

Background In patients with multiple myeloma (MM), the serum marker β2-microglobulin does not always accurately reflect tumor load. In contrast, whole-body (WB) MRI has shown high sensitivity for detecting bone lesions. Purpose To develop and validate a semiquantitative WB MRI scoring system for newly diagnosed MM and to compare it with the International Staging System (ISS) and Revised ISS (R-ISS). Materials and Methods This study included two retrospective groups (group 1, July 2015 to September 2021; group 2, February 2020 to September 2021) and one prospective group (group 3, October 2021 to February 2022) of patients with newly diagnosed MM. A new scoring system for MM was developed using spine MRI scans in group 1 and WB MRI scans in group 2 that integrated three features: (a) background marrow pattern, (b) number of focal bone lesions, and (c) presence of extramedullary or paramedullary lesions. The summed total score ranged from zero to nine. The interobserver agreement for each feature was assessed using Fleiss or Cohen weighted κ. WB MRI total scores in group 3 were compared across ISS and R-ISS stages using two-way analysis of variance. Results Groups 1, 2, and 3 included 103 patients (mean age, 62.1 years ± 9.1 [SD]; 60 men), 36 patients (mean age 65.4 years ± 11.3 [SD]; 19 women), and 39 participants (mean age, 62.0 years ± 11.7 [SD]; 20 men), respectively. The interobserver agreements for the three features composing the scoring system were substantial (κ range, 0.69-0.80). WB MRI total score increased with increasing ISS stage (mean score for ISS 1, 2, and 3 was 2.2, 4.2, and 5.8, respectively; P = .009) and R-ISS stage (mean score for R-ISS 1, 2, and 3 was 2.1, 3.8, and 5.9, respectively; P = .005). Conclusion The developed WB MRI scoring system for MM demonstrated substantial observer agreement and corresponded well with ISS and R-ISS stages. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Dragan and Messiou in this issue.

The role of staging in multiple myeloma

INTRODUCTION

The importance of cancer staging is determined by how accurately it can predict prognosis, and how useful it is for treatment decisions. Compared to other malignancies, multiple myeloma (MM) staging proved more challenging because of unreliable prognostic factors and wide-ranging life expectancy. As traditional MM staging continues to evolve, it requires reassessment of its prognostic and predictive value.

AREAS COVERED

The studies that included prognostic and predictive value of MM stages from 1975 through 2023 were selected for this review using PubMed, MEDLINE platforms. The history and evolution of MM staging are revisited, including its role in predicting survival, treatment planning and potential practical implications for the future. The role of MM staging for oncological practice and patient counseling is discussed.

EXPERT OPINION

The utility of the traditional MM staging remains unsatisfactory because it lacks a strong connection with the disease biology, prognosis or treatment planning. Additionally, it demonstrates a modest value for patient counseling because individual prognosis is subject to under- or overestimation, and the median survival or survival rates are difficult concepts to grasp. Although the role of MM stages may change in the future, the current research upholds the notion that MM staging benefits more medical research and clinical trials than oncological practice.

Clinical Value of FDG-PET/CT in Multiple Myeloma: An Update

FDG-PET/CT is a standardized imaging technique that has reached a great importance in the management of patients affected by Multiple Myeloma. It is proved, in fact, that it allows a deep evaluation of therapy efficacy and provides several prognostic indexes both at staging and after therapy. For this reason, it is now recognised as a gold standard for therapy assessment. Beside this, in reacent years FDG-PET/CT contribution to the understanding of Multiple Myeloma has progressively grown. Papers have been published analyzing the prognostic value of active disease volume measurement and standardization issues, the meaning of FDG positive paramedullary and extrameduallary disease, the prognostic impact of FDG positive minimal residual disease, the relation between focal lesions and clonal eterogenity of this disease and the comparison with whole body DWI-MR in terms of detection and therapy assessment. These newer aspects not of clinical impact yet, of FDG-PET/CT in Multiple Myeloma will be presented and discussed in this review.

Current Main Topics in Multiple Myeloma

Multiple Myeloma (MM) remains a difficult to treat disease mainly due to its biological heterogeneity, of which we are more and more knowledgeable thanks to the development of increasingly sensitive molecular methods that allow us to build better prognostication models. The biological diversity translates into a wide range of clinical outcomes from long-lasting remission in some patients to very early relapse in others. In NDMM transplant eligible (TE) patients, the incorporation of mAb as daratumumab in the induction regimens, followed by autologous stem cell transplantation (ASCT) and consolidation/maintenance therapy, has led to a significant improvement of PFS and OS.; however, this outcome remains poor in ultra-high risk MM or in those who did not achieve a minimal residual disease (MRD) negativity. Several trials are exploring cytogenetic risk-adapted and MRD-driven therapies in these patients. Similarly, quadruplets-containing daratumumab, particularly when administered as continuous therapies, have improved outcome of patients not eligible for autologous transplant (NTE). Patients who become refractory to conventional therapies have noticeably poor outcomes, making their treatment a difficult challenge in need of novel strategies. In this review, we will focus on the main points regarding risk stratification, treatment and monitoring of MM, highlighting the most recent evidence that could modify the management of this still incurable disease.

FDG-PET/CT and new radiopharmaceuticals in patients with multiple myeloma

Multiple myeloma is a monoclonal gammopathy, a clonal proliferative disorder of plasma cells that produces a protein called M or myeloma protein in the bone marrow, usually IgG or IgA. It accounts for 1% in the general cancer statistics and represents 10% of all hematologic tumours, with a cumulative incidence in Spain of about 5/100,000/year. The incidence increases with age, so that 50% of cases are diagnosed in patients over 75 years of age, being infrequent in the population under 40 years of age. This publication details the indications of FDG PET/CT for the staging and response assessment in patients with MM, accepted by the international working group on myeloma, as well as new molecular imaging radiopharmaceuticals with potential value for personalised medicine.

[Clinical Application and Limitations of Myeloma Response Assessment and Diagnosis System (MY-RADS)]

Multiple myeloma, which is a proliferative disease of plasma cells that originate from a single clone, is the second most common hematologic malignancy following non-Hodgkin lymphoma. In the past, its diagnosis was made based on clinical findings (so-called "CRAB") and a skeletal survey using radiographs. However, since the implementation of the International Myeloma Working Group's revised guideline regarding the radiologic diagnosis of multiple myeloma, whole-body (WB) MRI has emerged to play a central role in the early diagnosis of multiple myeloma. Diffusion-weighted imaging and fat quantification using Dixon methods enable treatment response assessment by MRI. In keeping with the trend, a multi-institutional and multidisciplinary consensus for standardized image acquisition and reporting known as the Myeloma Response Assessment and Diagnostic System (MY-RADS) has recently been proposed. This review aims to describe the clinical application of WB-MRI based on MY-RADS in multiple myeloma, discuss its limitations, and suggest future directions for improvement.

PET-CT in Clinical Adult Oncology: I. Hematologic Malignancies

PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging and evaluation of suspected recurrence. The goal of this 6-part series of review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for the more common adult malignancies. In the first article of this series, hematologic malignancies are addressed. The classification of these malignancies will be outlined, with the disclaimer that the classification of lymphomas is constantly evolving. Critical applications, potential pitfalls, and nuances of PET-CT imaging in hematologic malignancies and imaging features of the major categories of these tumors are addressed. Issues of clinical importance that must be reported by the imaging professionals are outlined. The focus of this article is on [¹⁸F] fluorodeoxyglucose (FDG), rather that research tracers or those requiring a local cyclotron. This information will serve as a resource for the appropriate role and limitations of PET-CT in the clinical management of patients with hematological malignancy for health care professionals caring for adult patients with hematologic malignancies. It also serves as a practical guide for imaging providers, including radiologists, nuclear medicine physicians and their trainees.

Unexpected Heterogeneity of Newly Diagnosed Multiple Myeloma Patients with Plasmacytomas

In multiple myeloma (MM), malignant plasma cells infiltrate the bone marrow. In some cases, plasma cells migrate out of the bone marrow creating either para-skeletal plasmacytomas (PS) or infiltrating soft tissues as extramedullary plasmacytomas (EMD). The aim of this study was to define risk groups in newly diagnosed MM (NDMM) patients with PS and EMD plasmacytomas. In total, 523 NDMM patients with PS plasmacytomas and 196 NDMM patients with EMD plasmacytomas were diagnosed in the Czech Republic between 2004 and 2021 using modern imaging methods. Patients’ data were analyzed from the Registry of Monoclonal Gammopathies of the Czech Myeloma Group. In NDMM patients with PS plasmacytomas, we found a subgroup with <5% of bone-marrow plasma cells to have the best prognosis (mPFS: 58.3 months (95% CI: 33.0−NA); mOS: not reached). The subgroup with >5% of bone-marrow plasma cells and ≥3 plasmacytomas had the worst prognosis (mPFS: 19.3 months (95% CI: 13.4−28.8), p < 0.001; mOS: 27.9 months (95% CI: 19.3−67.8), p < 0.001). Our results show association between tumor burden and prognosis of NDMM patients with plasmacytomas. In the case of PS plasmacytomas, NDMM patients with low BM PC infiltration have an excellent prognosis.

Advanced Imaging in Multiple Myeloma: New Frontiers for MRI

Plasma cell dyscrasias are estimated to newly affect almost 40,000 people in 2022. They fall on a spectrum of diseases ranging from relatively benign to malignant, the malignant end of the spectrum being multiple myeloma (MM). The International Myeloma Working Group (IMWG) has traditionally outlined the diagnostic criteria and therapeutic management of MM. In the last two decades, novel imaging techniques have been employed for MM to provide more information that can guide not only diagnosis and staging, but also treatment efficacy. These imaging techniques, due to their low invasiveness and high reliability, have gained significant clinical attention and have already changed the clinical practice. The development of functional MRI sequences such as diffusion weighted imaging (DWI) or intravoxel incoherent motion (IVIM) has made the functional assessment of lesions feasible. Moreover, the growing availability of positron emission tomography (PET)–magnetic resonance imaging (MRI) scanners is leading to the potential combination of sensitive anatomical and functional information in a single step. This paper provides an organized framework for evaluating the benefits and challenges of novel and more functional imaging techniques used for the management of patients with plasma cell dyscrasias, notably MM.

Recent developments on the application of molecular probes in multiple myeloma: Beyond [18F]FDG

Multiple myeloma (MM) is a neoplastic plasma cell proliferative disorder characterized by various osteolytic bone destruction as a radiological morphological marker. Functional imaging, particularly nuclear medicine imaging, is a promising method to visualize disease processes before the appearance of structural changes by targeting specific biomarkers related to metabolism ability, tumor microenvironment as well as neoplastic receptors. In addition, by targeting particular antigens with therapeutic antibodies, immuno-PET imaging can support the development of personalized theranostics. At present, various imaging agents have been prepared and evaluated in MM at preclinical and clinical levels. A summary overview of molecular functional imaging in MM is provided, and commonly used radiotracers are characterized.

Bone Disease in Multiple Myeloma: Biologic and Clinical Implications

Multiple Myeloma (MM) is a hematologic malignancy characterized by the proliferation of monoclonal plasma cells localized within the bone marrow. Bone disease with associated osteolytic lesions is a hallmark of MM and develops in the majority of MM patients. Approximately half of patients with bone disease will experience skeletal-related events (SREs), such as spinal cord compression and pathologic fractures, which increase the risk of mortality by 20–40%. At the cellular level, bone disease results from a tumor-cell-driven imbalance between osteoclast bone resorption and osteoblast bone formation, thereby creating a favorable cellular environment for bone resorption. The use of osteoclast inhibitory therapies with bisphosphonates, such as zoledronic acid and the RANKL inhibitor denosumab, have been shown to delay and lower the risk of SREs, as well as the need for surgery or radiation therapy to treat severe bone complications. This review outlines our current understanding of the molecular underpinnings of bone disease, available therapeutic options, and highlights recent advances in the management of MM-related bone disease.

18F-FDG Versus Non-FDG PET Tracers in Multiple Myeloma

Multiple myeloma (MM) accounts for 0.9% of cancer diagnoses, and incidence and mortality rate have increased in previous years. 18F-fluorodeoxyglucose (FDG) PET-computed tomography (CT) is an established modality for MM evaluation. MR imaging is helpful where 18F-FDG PET-CT is lacking. To standardize PET reporting, methods like Italian Myeloma Criteria for PET Use and Deauville criteria have been studied. Tracers like 11C-acetate and 11C-choline/18F-fluoromethylcholine (FCH) have shown higher sensitivity and detected more focal lesions and diffuse involvement than 18F-FDG PET-CT. 18F-FCH showed higher maximum standardized uptake value than 18FDG. 11C-methionine appears to be the best radiopharmaceutical, apart from 18F-FDG, for evaluating MM.

Histogram Analysis Based on Apparent Diffusion Coefficient Maps of Bone Marrow in Multiple Myeloma: An Independent Predictor for High-risk Patients Classified by the Revised International Staging System

RATIONALE AND OBJECTIVES

The revised International Staging System (R-ISS) is the current risk stratifier for patients with newly diagnosed multiple myeloma (NDMM). We used histogram analysis based on apparent diffusion coefficient (ADC) maps of bone marrow to predict high-risk NDMM patients staged as R-ISS stage III.

MATERIAL AND METHODS

Sixty-one NDMM patients were recruited prospectively and underwent whole-body diffusion-weighted MRI. Mean ADC and four ADC-based histogram parameters of representative background bone marrow were quantified with TexRAD software, including ADC entropy, ADC standard deviation (SD), ADC skewness and ADC kurtosis. Diagnostic performance to discriminate R-ISS III from I/II disease was evaluated by receiver-operating characteristics curve (ROC). Univariate and multivariate analysis using stepwise logistic regression model was performed to identify predictors for R-ISS III.

RESULTS

ADC entropy of background marrow showed the highest areas under the ROC (0.784, sensitivity = 93.3%, specificity = 63.0%) for the detection of R-ISS stage III disease. Multivariate analysis showed that increased ADC entropy (>3.612) of background marrow can independently predict R-ISS stage III disease in the overall patients (Model 1 corrected for diffuse infiltration [DI] pattern: odds ratio [OR], 10.647; p = 0.008; Model 2 corrected for mean ADC: OR, 10.485; p = 0.010) and in the subgroup with DI pattern (OR, 7.043; p = 0.037).

CONCLUSION

ADC entropy of background marrow may serve as a sensitive imaging biomarker facilitating the detection of high-risk NDMM patients staged as R-ISS stage III. Increased ADC entropy of background marrow can independently predict R-ISS stage III in the overall patients and in the subgroup with DI pattern.

18 F-FDG PET/CT and MRI in the Management of Multiple Myeloma: A Comparative Review

During the last two decades, the imaging landscape of multiple myeloma (MM) has evolved with whole-body imaging techniques such as fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) and MRI replacing X-ray skeletal survey. Both imaging modalities have high diagnostic performance at the initial diagnosis of MM and are key players in the identification of patients needing treatment. Diffusion-weighted MRI has a high sensitivity for bone involvement, while 18F-FDG PET/CT baseline parameters carry a strong prognostic value. The advent of more efficient therapeutics, such as immunomodulatory drugs and proteasome inhibitors, has called for the use of sensitive imaging techniques for monitoring response to treatment. Diffusion-weighted MRI could improve the specificity of MRI for tumor response evaluation, but questions remain regarding its role as a prognostic factor. Performed at key time points of treatment in newly diagnosed MM patients, 18F-FDG PET/CT showed a strong association with relapse risk and survival. The deployment of minimal residual disease detection at the cellular or the molecular level may raise questions on the role of these imaging techniques, which will be addressed. This review summarizes and outlines the specificities and respective roles of MRI and 18F-FDG PET/CT in the management of MM.

Amino Acid and Proliferation PET/CT for the Diagnosis of Multiple Myeloma

Multiple myeloma (MM) is a hematologic malignancy characterized by infiltration of monoclonal plasma cells in the bone marrow (BM). The standard examination performed for the assessment of bone lesions has progressed from radiographic skeletal survey to the more advanced imaging modalities of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT). The Durie-Salmon PLUS staging system (upgraded from the Durie-Salmon staging system) applies 2-[18F]-fluoro-2-deoxy-glucose (18F-FDG) PET/CT, and MRI findings to the staging of MM, and 18F-FDG PET/CT has been incorporated into the International Myeloma Working Group (IMWG) guidelines for the diagnosis and staging of MM. However, 18F-FDG PET/CT has significant limitations in the assessment of diffuse BM infiltration and in the differentiation of MM lesions from inflammatory or infectious lesions. The potential of several new PET tracers that exploit the underlying disease mechanism of MM has been evaluated in terms of improving the diagnosis. L-type amino acid transporter 1 (LAT1), a membrane protein that transports neutral amino acids, is associated with cell proliferation and has strong ability to represent the status of MM. This review evaluates the potential of amino acid and proliferation PET tracers for diagnosis and compares the characteristics and accuracy of non-FDG tracers in the management of patients with MM.

Imaging of treatment response and minimal residual disease in multiple myeloma: state of the art WB-MRI and PET/CT

Bone imaging has been intimately associated with the diagnosis and staging of multiple myeloma (MM) for more than 5 decades, as the presence of bone lesions indicates advanced disease and dictates treatment initiation. The methods used have been evolving, and the historical radiographic skeletal survey has been replaced by whole body CT, whole body MRI (WB-MRI) and [¹⁸F]FDG-PET/CT for the detection of bone marrow lesions and less frequent extramedullary plasmacytomas.Beyond diagnosis, imaging methods are expected to provide the clinician with evaluation of the response to treatment. Imaging techniques are consistently challenged as treatments become more and more efficient, inducing profound response, with more subtle residual disease. WB-MRI and FDG-PET/CT are the methods of choice to address these challenges, being able to assess disease progression or response and to detect "minimal" residual disease, providing key prognostic information and guiding necessary change of treatment.This paper provides an up-to-date overview of the WB-MRI and PET/CT techniques, their observations in responsive and progressive disease and their role and limitations in capturing minimal residual disease. It reviews trials assessing these techniques for response evaluation, points out the limited comparisons between both methods and highlights their complementarity with most recent molecular methods (next-generation flow cytometry, next-generation sequencing) to detect minimal residual disease. It underlines the important role of PET/MRI technology as a research tool to compare the effectiveness and complementarity of both methods to address the key clinical questions.

Diffuse vertebral marrow changes at MRI: Multiple myeloma or normal?

Five MRI patterns of marrow involvement (diffuse, focal, combined diffuse and focal, variegated, and normal) are observed in patients with a marrow proliferative disorder including MM. The wide range of marrow involvement patterns in monoclonal plasma cell proliferative disorders mirrors that of their natural histories that can vary from indolent to rapidly lethal. MRI of the axial bone marrow contributes to stage these disorders, but it should not be obtained for disease detection and characterization because of its limited specificity and sensitivity. At MRI, diffuse benign hematopoietic marrow hyperplasia and marrow heterogeneities in elderly patients mimic the diffuse and variegated patterns observed in MM patients. Careful analysis of fat- and fluid-sensitive MR images and quantitative marrow assessment by using MRI and FDG-PET can contribute in differentiating these changes from those associated with neoplastic marrow infiltration, with some residual overlapping findings.

11C-acetate positron emission tomography is more precise than 18F-fluorodeoxyglucose positron emission tomography in evaluating tumor burden and predicting disease risk of multiple myeloma

The optimal method of tumor burden evaluation in newly diagnosed multiple myeloma (NDMM) is yet to be determined. This study aimed to compare the value of ¹¹C-acetate positron-emission tomography (PET)/computed tomography (CT) (AC-PET and ¹⁸F-fluorodeoxyglucose PET/CT (FDG-PET) in the assessment of tumor burden in NDMM. This study evaluated 64 NDMM patients between February 2015 and July 2018. AC-PET and FDG-PET were used to assess myeloma lesions. The clinical data, imaging results, and their correlations were analyzed. Diffuse bone marrow uptake in AC-PET was significantly correlated with biomarkers for tumor burden, including serum hemoglobin (P = 0.020), M protein (P = 0.054), the percentage of bone marrow plasma cells (P < 0.001), and the Durie–Salmon stage of the disease (P = 0.007). The maximum standard uptake value (SUV_max) of focal lesions and high diffuse bone marrow uptake in AC-PET showed stronger correlations with high-risk disease (P = 0.017, P = 0.013) than those in FDG-PET. Moreover, the presence of diffuse bone marrow uptake, more than ten focal lesions, and an SUV_max of focal lesions of > 6.0 in AC-PET, but not in FDG-PET, predicted a higher probability of disease progression and shorter progression-free survival (P < 0.05). AC-PET outperformed FDG-PET in tumor burden evaluation and disease progression prediction in NDMM.

Comparison between tumour metabolism derived from 18F-FDG PET/CT and accurate cytogenetic stratification in newly diagnosed multiple myeloma patients

Background

¹⁸F-fluorodeoxyglucose positron emission tomography integrated with computed tomography (¹⁸F-FDG PET/CT) is a useful tool for baseline staging in newly diagnosed multiple myeloma (MM) but also for prognostic stratification. This monocentric retrospective study aimed at examining the relation between baseline tumour metabolism assessed by ¹⁸F-FDG PET/CT and linear predictor (LP) score, a new cytogenetic stratification score.

Methods

From March 2012 to March 2019, 57 patients with newly diagnosed MM addressed to our institution for baseline ¹⁸F-FDG PET/CT were included. LP score was determined on systematic iliac crest bone marrow samples. Obtained on CD138-sorted bone marrow plasma cells, this recent composite cytogenetic stratification is a 6-marker based weighted score using fluorescence in situ hybridization (FISH) ± single nucleotide polymorphism (SNP) arrays. We compared quantitative metabolic parameters and LP score using a Kruskal-Wallis test and visual suspicion of diffuse bone marrow involvement (DBI; based on hepatic background as threshold of positivity) and cytogenetic data using a Chi-squared test.

Results

The distribution of total metabolic tumour volume (TMTV) and total lesion glycolysis (TLG) values among the three LP score categories was almost stochastic, with no significant association (P=0.70). Additionally, no significant association between TMTV/TLG and any of the six cytogenetic abnormalities included in LP score calculation. A significant association was found between visual high suspicion of DBI and LP score (P=0.036), and between this visual parameter and the presence of 1q gain (P=0.049).

Conclusions

There is no significant association between quantitative metabolic parameters assessed with ¹⁸F-FDG PET/CT and LP score in patients with newly diagnosed MM, suggesting a potential complementarity of these biomarkers for prognostic stratification. A significant association was found between high visual suspicion of DBI and LP score.

Skeletal Survey in Multiple Myeloma: Role of Imaging

Bone disease is the hallmark of multiple myeloma. Skeletal lesions are evaluated to establish the diagnosis, to choose the therapies and also to assess the response to treatments. Due to this, imaging procedures play a key role in the management of multiple myeloma. For decades, conventional radiography has been the standard imaging modality. Subsequently, advances in the treatment of multiple myeloma have increased the need for an accurate evaluation of skeletal disease. The introduction of new high performant imaging tools, such as whole-body lowdose computed tomography, different types of magnetic resonance imaging studies, and 18F-fluorodeoxyglucose positron emission tomography, replaced the conventional radiography. In this review, we analyze the diagnostic potentials, indications of use, and applications of the imaging tools nowadays available. Whole-body low-dose CT should be considered as the imaging modality of choice for the initial assessment of multiple myeloma lytic bone lesions. MRI is the gold-standard for the detection of bone marrow involvement, while PET/CT is the preferred technique in the assessment of response to therapy. Both MRI and PET/CT are able to provide prognostic information.

Learning curves in radiological reporting of whole-body MRI in plasma cell disease: a retrospective study

BACKGROUND

The plasma cell disease is been studying by the whole-body MRI technology. However, the time requested to learn this radiological technique is unknown.

PURPOSE

To esteem, quantitatively and qualitatively, the essential time to learn the whole-body MRI diffusion-weighted imaging with background body signal suppression in patients with plasma cell disease.

MATERIALS AND METHODS

Between January 2015 and February 2017, three readers in-training with different levels of experience examined the anonymised and randomised whole-body MRI images of 52 patients with a diagnosis of plasma cell disease and analysed their morphological (T1w, T2w with and without fat suppression) and functional sequences. Reports of an expert radiologist were considered the standard of reference. Images were analysed in two sessions, during which each reader was timed. Readers reported the number of segments with lesions and staged the disease using the Durie-Salmon PLUS staging system. Weighted Cohen's ĸ and Z-test were used to compare the trainees' reports with those of the expert radiologist, and learning curves were drawn up to show changes between the two sessions.

RESULTS

Weighted Cohen's ĸ of number of lesioned segments increased from 0.536 ± 0.123 to 0.831 ± 0.129 (Prob > Z under 0.005), thus approaching the goal of ĸ > 0.8. Trainees reached the level of experienced radiologist in terms of time by the 33rd patient. Agreement concerning the Durie-Salmon PLUS increased from 0.536 ± 0.123 to 0.831 ± 0.129 (Prob > Z under 0.005).

CONCLUSIONS

The findings of this study demonstrate that whole-body MRI with DWIBS can be learned in about 80 reports and leads to a high level of inter-observer concordance when using the Durie-Salmon PLUS staging system.

The Prevalence of Euthyroid Hypertriiodothyroninemia in Newly Diagnosed Multiple Myeloma and its Clinical Characteristics

OBJECTIVE

To evaluate the prevalence of euthyroid hypertriiodothyroninemia and/or hyperthyroxinemia and its clinical characteristics in multiple myeloma (MM) patients.

METHODS

Previously untreated, newly diagnosed patients with MM were enrolled at the Beijing Chao-yang Hospital between January 2016 and December 2019. Thyroid function and clinical characteristics were analyzed.

RESULTS

A total of 105 patients were enrolled in this study. Thirteen (12.38%) patients exhibited euthyroid hypertriiodothyroninemia with strikingly elevated total triiodothyronine (TT3) levels (>8 ng/mL). Among these 13 patients, 12 patients were immunoglobulin (Ig) G type (92.31%), and 1 patient was light-chain κ type (7.69%). Compared with other patients with MM, patients with hypertriiodothyroninemia were more likely to be IgG type and had higher serum globulin and lower albumin levels and more advanced International Staging System stage (all P < .05). Among the 13 euthyroid hypertriiodothyroninemia patients, 8 patients have been followed up and checked for thyroid function. The TT3 levels in all 8 patients were normalized to the reference range after antimyeloma chemotherapy.

CONCLUSION

About 12% of patients with MM had euthyroid hypertriiodothyroninemia. Their strikingly elevated TT3 was normalized after chemotherapy. Clinicians should be aware of the possibility of high TT3 levels in euthyroid patients with MM and the potential risk of MM in patients with strikingly elevated TT3.

Socioeconomic Factors and Survival of Multiple Myeloma Patients

BACKGROUND

Outcome of Multiple Myeloma (MM) patients has improved as the result of the introduction of novel medications and use of autologous hematopoietic cell transplantation. However, this improvement comes at the expense of increased financial burden. It is largely unknown if socioeconomic factors influence MM survival.

METHODS

We used the National Cancer Database, a database that houses data on 70% of cancer patients in the US, to evaluate the effect of socioeconomic factors on the survival of 117,926 MM patients diagnosed between 2005 and 2014.

RESULTS

Patients aged ≥65 years who were privately insured lived longer than patients with Medicare (42 months vs. 31 months, respectively, p < 0.0001). Treatment in academic institutions led to better survival (HR: 1.49, 95% CI: 1.39, 1.59). Younger age, fewer comorbidities, treatment in academic centers, and living in a higher median income area were significantly associated with improved survival. After adjusting for confounders, survival of Medicare patients was similar to those with private insurance. However, the hazard of death remained higher for patients with Medicaid (HR: 1.59, 95% CI: 1.36, 1.87) or without insurance (HR: 1.62, 95% CI: 1.32, 1.99), compared to privately insured patients.

CONCLUSION

Economic factors and treatment facility type play an important role in the survival of MM patients.

Virtual calcium-suppression in dual energy computed tomography predicts metabolic activity of focal MM lesions as determined by fluorodeoxyglucose positron-emission-tomography

PURPOSE

Recent studies showed that dual energy CT (DECT) allows for detection of bone marrow infiltration in multiple myeloma (MM) by obtaining virtual non-calcium (VNCa) images. This feasibility study investigated, if VNCa imaging might discriminate metabolically active, focal lesions in MM against avital lesions in MM patients, considering fluorodeoxyglucose positron-emission-tomography CT (FDG PET/CT) as the standard of reference.

METHOD

The study included 60 osteolytic lesions in 10 consecutive low-dose whole body CT scans of patients with MM, who underwent both FDG PET/CT and DECT at a tertiary care university hospital. Circular ROI measurements were performed in predefined lesions on the monoenergetic CT (MECT) and VNCa images by three blinded radiologists. Each lesion was rated vital or avital by a blinded specialist of nuclear medicine, based on their FDG metabolism.

RESULTS

Each of the three readers could separate FDG PET/CT negative and positive MM lesions when analyzing the VNCa images, while MECT did not show a significant difference. Best results were yielded by high calcium suppression with excellent inter-rater reliability (average sensitivity 0.91, specificity 0.88, cutoff -46.9 HU), followed by medium and low calcium suppression.

CONCLUSIONS

In contrast to MECT imaging, VNCa imaging in DECT appears to be feasible to assess metabolic activity of focal MM lesions as defined by the standard of reference, FDG PET/CT. Considering the higher cost and radiation exposure of FDG PET/CT, DECT VNCa imaging might develop to be the modality of choice to assess metabolic activity of focal MM lesions.

Whole-Body Functional MRI and PET/MRI in Multiple Myeloma

Simple Summary

Whole-body magnetic resonance imaging (MRI) is recognized as the most sensitive imaging technique for the detection of bone marrow infiltration, and was therefore, recently included in the new diagnostic myeloma criteria, as proposed by the International Myeloma Working Group. The use of diffusion-weighted MRI further improved the performances of whole-body MRI in the setting of multiple myeloma, and its systematic implementation in general clinical practice is now recommended. Whole-body, dynamic, contrast-enhanced MRI might provide further information on lesions vascularity and might help evaluate response to treatment. Hybrid PET/MRI might act as the optimal imaging modality, owing to the association of the best techniques for both detecting bone marrow involvement and evaluating treatment response, providing one-stop-shop imaging in a whole-body scale. This review provides an overview on the value of whole-body MRI, including diffusion-weighted and dynamic contrast-enhanced MRI and whole-body ¹⁸F-FDG PET/MRI in diagnosis, staging, and response evaluation in multiple myeloma.

Abstract

Bone disease is one of the major features of multiple myeloma (MM), and imaging has a pivotal role in both diagnosis and follow-up. Whole-body magnetic resonance imaging (MRI) is recognized as the gold standard for the detection of bone marrow involvement, owing to its high sensitivity. The use of functional MRI sequences further improved the performances of whole-body MRI in the setting of MM. Whole-body diffusion-weighted (DW) MRI is the most attractive functional technique and its systematic implementation in general clinical practice is now recommended by the International Myeloma Working Group. Whole-body dynamic contrast-enhanced (DCE) MRI might provide further information on lesions vascularity and help evaluate response to treatment. Whole Body PET/MRI is an emerging hybrid imaging technique that offers the opportunity to combine information on morphology, fat content of bone marrow, bone marrow cellularity and vascularization, and metabolic activity. Whole-body PET/MRI allows a one-stop-shop examination, including the most sensitive technique for detecting bone marrow involvement, and the most recognized technique for treatment response evaluation. This review aims at providing an overview on the value of whole-body MRI, including DW and DCE MRI, and combined whole-body ¹⁸F-FDG PET/MRI in diagnosis, staging, and response evaluation in patients with MM.

Use of disease embedding technique to predict the risk of progression to end-stage renal disease

The accurate prediction of progression of Chronic Kidney Disease (CKD) to End Stage Renal Disease (ESRD) is of great importance to clinicians and a challenge to researchers as there are many causes and even more comorbidities that are ignored by the traditional prediction models. We examine whether utilizing a novel low-dimensional embedding model disease2disease (D2D) learned from a large-scale electronic health records (EHRs) could well clusters the causes of kidney diseases and comorbidities and further improve prediction of progression of CKD to ESRD compared to traditional risk factors. The study cohort consists of 2,507 hospitalized Stage 3 CKD patients of which 1,375 (54.8%) progressed to ESRD within 3 years. We evaluated the proposed unsupervised learning framework by applying a regularized logistic regression model and a cox proportional hazard model respectively, and compared the accuracies with the ones obtained by four alternative models. The results demonstrate that the learned low-dimensional disease representations from EHRs can capture the relationship between vast arrays of diseases, and can outperform traditional risk factors in a CKD progression prediction model. These results can be used both by clinicians in patient care and researchers to develop new prediction methods.

Osteoclast stimulatory transmembrane protein (OC-STAMP) is a promising molecular prognostic indicator for multiple myeloma

BACKGROUND

Currently, the prognostic stratification and therapeutic evaluation systems for multiple myeloma (MM) lack specific molecular indicators. OC-STAMP is a new gene and is also highly expressed in MM.

METHODS

A total of 160 MM patients have been investigated with both quantitative reverse transcription PCR (RT-qPCR), flow cytometry (FCM) and cytogenetic FISH on the same mononuclear cells isolated from bone marrow specimens.

RESULTS

We found that OC-STAMP mRNA levels were significantly higher in newly diagnosed cases of MM than in healthy donors (median, 0.52% vs. 0.02%, P < .001). Moreover, the changes in the OC-STAMP mRNA levels paralleled the disease stages and minimal residual disease, as detected by FCM. Furthermore, we found that patients with high OC-STAMP mRNA levels were more likely to develop ≥3 bone lesions, be diagnosed with Durie-Salmon stages III, and have the P53 (17p13) deletion. In addition, advanced stage patients with high OC-STAMP mRNA levels had a lower 4-year progression-free survival (5.6% vs. 22.9%, P = .0055) and a worse 4-year overall survival (25.8% vs. 48.8%, P = .0137) compared to patients with low mRNA levels of this indicator.

CONCLUSIONS

OC-STAMP may be a promising molecular indicator to monitor treatment effects and participate in the prognostic stratification of MM.

Tumor load in patients with multiple myeloma: β₂-microglobulin levels versus low-dose whole-body CT

OBJECTIVE

Beta-2-microglobulin is a serum marker of tumor burden in multiple myeloma (MM). Our aim was to correlate serum β₂-microglobulin levels in patients with MM to tumor burden determined by low-dose whole-body CT (LDWBCT).

MATERIALS AND METHODS

A total of 52 patients with newly diagnosed, untreated MM who underwent LDWBCT were included. LDWBCT scans were assessed by two musculoskeletal radiologists in consensus for focal lesions. The Durie and Salmon PLUS staging system was used for staging patients in stages I-III. β₂-microglobulin was also subdivided into stages I-III on the basis of the multiple myeloma International Staging System (ISS).

RESULTS

Using the Durie and Salmon PLUS staging system criteria for image evaluation, we were able to identify stage I MM in 17 patients, stage II MM in nine patients, and stage III MM in 26 patients. Eight of nine patients with stage II MM and 16 of 26 patients with stage III MM had normal β₂-microglobulin levels. Thus, 24 of 35 patients (68.6%) had 5 or more focal lesions and false-negative β₂-microglobulin levels.

CONCLUSION

Serum β₂-microglobulin levels alone may not indicate the full extent of tumor burden in a significant subset of myeloma patients.

MRI versus 18F-FDG-PET/CT for detecting bone marrow involvement in multiple myeloma: diagnostic performance and clinical relevance

PURPOSE

To compare the diagnostic performance of MRI and ¹⁸F-FDG-PET/CT in detecting bone marrow involvement (BMI) in patients with multiple myeloma (MM).

MATERIALS AND METHODS

This retrospective study was approved by our Institutional Review Board. Two radiologists and two nuclear medicine specialists independently and blindly reviewed 84 pairs of MRI and PET/CT scans obtained in 73 MM patients. Readers assessed the presence and patterns of BMI. The best valuable comparator (BVC) for BMI was established by a panel review of all baseline and follow-up imaging, and biological and pathological information. Intra- and inter-reader agreement and correlation between MRI and PET/CT were assessed using the prevalence-adjusted bias-adjusted kappa (k) coefficient. Diagnostic performance of MRI and PET/CT in detecting BMI was evaluated from ROC characteristics. Association between imaging and biological, pathological, and clinical findings was assessed using Wilcoxon rank-sum and chi-square tests.

RESULTS

Intra- and inter-reader agreement was very good for MRI (k = 0.90 [0.81; 1.00] and 0.88 [0.78; 0.98]). Intra- and inter-reader agreement was good for PET/CT (k = 0.80 [0.69; 0.91] and 0.71 [0.56; 0.86]). The sensitivity of MRI to detect BMI (97% [90%; 100%]) was significantly superior to that of PET/CT (76% [64%; 85%]) (p < 0.001). The specificity of MRI (86% [57%; 98%]) was lower than that of PET/CT (93% [66%; 100%]), without reaching statistical significance (p = 0.32). There was a strong correlation between decisions regarding patient management and PET/CT findings (p < 0.001).

CONCLUSION

MRI is significantly more sensitive than PET/CT to detect BMI in MM. Patient management is more strongly correlated with PET/CT findings.

KEY POINTS

• MRI and PET/CT have very close diagnostic value for the detection of bone marrow involvement in multiple myeloma. • MRI has a significantly higher sensitivity and better reproducibility. • PET/CT findings appear to have a higher impact on clinical decisions.

Whole-body diffusion-weighted MRI for evaluation of response in multiple myeloma patients following bortezomib-based therapy: A large single-center cohort study

PURPOSE

To determine the feasibility of whole-body diffusion-weighted imaging (WB-DWI) MRI for evaluation of response in patients with multiple myeloma (MM) following bortezomib-based therapy and to explore the direction of apparent diffusion coefficient (ADC) changes upon treatment.

METHOD

Seventy-two MM patients who underwent WB-DWI MRI before and after bortezomib-based chemotherapy (21 weeks) were evaluated retrospectively. The estimated tumor volume (eTV) and ADC_mean values before and after chemotherapy were calculated and compared between deep and non-deep responders. Predictive value of baseline ADC_mean was calculated to predict the trend of ADC_mean change following treatment.

RESULTS

Fifty-five patients were classified as deep responders, and 17 cases were assigned as non-deep responders. For 327 focal lesions (FLs), the ADC_mean value was significantly increased from baseline to post-treatment. However, the ADC_mean value was significantly decreased following treatment in 846 representative diffuse lesions. Diffuse lesions showed a significantly decreased ADC_mean value in deep responders, whereas no significant variation in ADC_mean value in FLs was found between deep and non-deep responders. Baseline ADC_mean at a specific value (0.808 × 10^-3  mm²/s) yielded a maximum specificity (68.05%) and sensitivity (54.09%) in predicting increase of post-treatment ADC_mean.

CONCLUSIONS

The ADC_mean value was significantly decreased in MM patients with diffuse pattern, while it was significantly increased in those with focal pattern following bortezomib-based treatment. WB-DWI MRI could be used to discriminate deep response to induction treatment in MM patients with diffuse infiltration pattern. Baseline ADC_mean value might have a potential to predict the trend of ADC_mean change following treatment.

Multiple myeloma of young adult presented with paraplegia, rare case report in Saudi Arabia

Multiple myeloma is the second most common hematologic malignancy. It is characterized by the neoplastic proliferation of plasma cells in the bone marrow, leading to excessive production of monoclonal immunoglobulin. The mean age at diagnosis is 65 years. There are only a few cases of Multiple Myeloma arising in young population reported in the literature. We present a case of 33-years-old male presented with complete bilateral lower limbs paralysis and loss of sensation which were gradual in onset and accompanied by upper and lower back pain for 1 month. MRI of the whole spine show multiple infiltrative bone marrow high signal in T2 and STIR sequences involve C4 and the upper dorsal vertebral bodies and the spinous process of D4 with left para-spinal and large posterior epidural mass compress the spinal cord. CT guidance obtains three samples from the mass and placed in formalin in separate containers. Histopathology examination revealed neoplastic growth composed of Sheet of diffuse atypical plasma cells infiltrating fibro collagenous and adipose tissue. Although Multiple myeloma is a disease of elderly; it still could present in young age group. Histopathology examination is the gold standard for diagnosis.

Outcome of paraosseous extra-medullary disease in newly diagnosed multiple myeloma patients treated with new drugs

Extramedullary disease is relatively frequent in multiple myeloma, but our knowledge on the subject is limited and mainly relies on small case series or single center experiences. Little is known regarding the role of new drugs in this setting. We performed a meta-analysis of eight trials focused on the description of extramedullary disease characteristics, clinical outcome, and response to new drugs. A total of 2,332 newly diagnosed myeloma patients have been included; 267 (11.4%) had extramedullary disease, defined as paraosseous in 243 (10.4%), extramedullary plasmocytoma in 12 (0.5%), and not classified in 12 (0.5%) patients. Median progression-free survival was 25.3 months and 25.2 in extramedullary disease and non-extramedullary disease patients, respectively. In multivariate analysis the presence of extramedullary disease did not impact on progression-free survival (hazard ratio 1.15, P=0.06), while other known prognostic factors retained their significance. Patients treated with immunomodulatory drugs, mainly lenalidomide, or proteasome inhibitors had similar progression-free survival and progression-free survival-2 regardless of extramedullary disease presence. Median overall survival was 63.5 months and 79.9 months (P=0.01) in extramedullary and non-extramedullary disease patients, respectively, and in multivariate analysis the presence of extramedullary disease was associated with a reduced overall survival (hazard ratio 1.41, P<0.001), in line with other prognostic factors. With the limits of the use of low sensitivity imaging techniques, that lead to an underestimation of extramedullary disease, we conclude that in patients treated with new drugs the detrimental effect of extramedullary disease at diagnosis is limited, that lenalidomide is effective as are proteasome inhibitors, and that these patients tend to acquire a more aggressive disease in later stages. (EUDRACT2005-004714-32, NCT01063179 NCT00551928, NCT01091831, NCT01093196, NCT01190787, NCT01346787, NCT01857115).

Fludeoxyglucose F 18 PET/Computed Tomography Evaluation of Therapeutic Response in Multiple Myeloma

Multiple myeloma is a malignancy of terminally differentiated plasma cells representing the second most common hematological malignancy. The recognition that disease outside the marrow can significantly influence the outcome of patients has highlighted the importance of imaging to define presence of tumor. Recent studies have demonstrated an added value of using imaging to assess presence of disease both inside and outside the marrow. To this end, the response criteria have been revised to include PET/computed tomography to be used in conjunction with bone marrow assessment to determine minimal residual disease status.

PET with Fluorodeoxyglucose F 18/Computed Tomography as a Staging Tool in Multiple Myeloma

In the past decade novel treatment options have dramatically prolonged the survival of patients with multiple myeloma. PET combined with computed tomography (CT) is a sensitive and reliable functional imaging tool that enables diagnosis and assessment of response to chemotherapy/radiotherapy, and combines high sensitivity in identifying both lytic lesions and extramedullary soft-tissue masses with the ability to provide reliable prognostic information in the management of patients with myeloma. This review comprises a comprehensive overview of PET with fluorodeoxyglucose F 18/CT imaging in combination with other convenient imaging procedures, and attempts at standardization with emphasis on post-therapy findings in patients with myeloma.

Phase I study of the anti-FcRH5 antibody-drug conjugate DFRF4539A in relapsed or refractory multiple myeloma

FcRH5 is a cell surface marker enriched on malignant plasma cells when compared to other hematologic malignancies and normal tissues. DFRF4539A is an anti-FcRH5 antibody-drug conjugated to monomethyl auristatin E (MMAE), a potent anti-mitotic agent. This phase I study assessed safety, tolerability, maximum tolerated dose (MTD), anti-tumor activity, and pharmacokinetics of DFRF4539A in patients with relapsed/refractory multiple myeloma. DFRF4539A was administered at 0.3-2.4 mg/kg every 3 weeks or 0.8-1.1 mg/kg weekly as a single-agent by intravenous infusion to 39 patients. Exposure of total antibody and antibody-conjugate-MMAE analytes was linear across the doses tested. There were 37 (95%) adverse events (AEs), 8 (21%) serious AEs, and 15 (39%) AEs ≥ grade 3. Anemia (n = 10, 26%) was the most common AE considered related to DFRF4539A. Two cases of grade 3 acute renal failure were attributed to DFRF4539A. There were no deaths; the MTD was not reached. DFRF4539A demonstrated limited activity in patients at the doses tested with 2 (5%) partial response, 1 (3%) minimal response, 18 (46%) stable disease, and 16 (41%) progressive disease. FcRH5 was confirmed to be expressed and occupied by antibody post-treatment and thus remains a valid myeloma target. Nevertheless, this MMAE-based antibody-drug-conjugate targeting FcRH5 was unsuccessful for myeloma.

Comparison of bone lesion distribution between prostate cancer and multiple myeloma with whole-body MRI

PURPOSE

To assess the distribution of bone lesions in patients with prostate cancer (PCa) and those with multiple myeloma (MM) using whole-body magnetic resonance imaging (MRI); and to assess the added value of four anatomical regions located outside the thoraco-lumbo-pelvic area to detect the presence of bone lesions in a patient-based perspective.

MATERIALS AND METHODS

Fifty patients (50 men; mean age, 67±10 [SD] years; range, 59-87 years) with PCa and forty-seven patients (27 women, 20 men; mean age, 62.5±9 [SD] years; range, 47-90 years) with MM were included. Three radiologists assessed bone involvement in seven anatomical areas reading all MRI sequences.

RESULTS

In patients with PCa, there was a cranio-caudal increasing prevalence of metastases (22% [11/50] in the humeri and cervical spine to 60% [30/50] in the pelvis). When the thoraco-lumbo-pelvic region was not involved, the prevalence of involvement of the cervical spine, proximal humeri, ribs, or proximal femurs was 0% in patients with PCa and≥4% (except for the cervical spine, 0%) in those with MM.

CONCLUSION

In patients with PCa, there is a cranio-caudal positive increment in the prevalences of metastases and covering the thoraco-lumbo-pelvic area is sufficient to determine the metastatic status of a patient with PCa. In patients with MM, there is added value of screening all regions, except the cervical spine, to detect additional lesions.