Dynamic contrast-enhanced magnetic resonance imaging identifies a subgroup of patients with asymptomatic monoclonal plasma cell disease and pathologic microcirculation

DCE-MRI to distinguish all monoclonal plasma cell disease stages and correlation with diffusion-weighted MRI/PET-based biomarkers in a hybrid simultaneous whole body-2-[18F]FDG-PET/MRI imaging approach

BACKGROUND

Dynamic contrast-enhanced-MRI (DCE-MRI) is able to study bone marrow angiogenesis in patients with multiple myeloma (MM) and asymptomatic precursor diseases but its role in the management of MM has not yet been established. The aims of this prospective study was to compare DCE-MRI-based parameters between all monoclonal plasma cell disease stages in order to find out discriminatory parameters and to seek correlations with other diffusion-weighted MRI and positron emission tomography (PET)-based biomarkers in a hybrid simultaneous whole-body-2-[18F]fluorodeoxyglucose (FDG)-PET/MRI (WB-2-[18F]FDG-PET/MRI) imaging approach.

METHODS

Patients with newly diagnosed Monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM) or symptomatic MM according to international myeloma working group and underwent WB-2-[18F]FDG-PET/MRI imaging including bone marrow DCE sequences at the Nantes University Hospital were prospectively enrolled in this study before receiving treatment.

RESULTS

One hundred and sixty-seven patients (N = 167, mean age: 64 years ± 11 [Standard deviation], 66 males) were considered for the analysis. DCE-MRI-based Peak Enhancement Intensity (PEI), Time to PEI (TPEI) and their maximum intensity time ratio (MITR: PEI/TPEI) values were significantly different between the different monoclonal plasma cell disease stages, PEI values increasing and TPEI values decreasing progressively along the spectrum of plasma cell disorders, from MGUS stage to symptomatic multiple myeloma. PEI values were significantly higher in patients with diffuse bone marrow involvement (either in PET or in MRI images) than in those without diffuse bone marrow involvement, unlike TPEI values. PEI and TPEI values were not significantly different between patients with or without focal bone lesions.

CONCLUSION

Different DCE-MRI-based parameters (PEI, TPEI, MITR) could significantly differentiate all monoclonal plasma cell disease stages and complemented conventional MRI and PET-based biomarkers.

Predicting cytogenetic risk in multiple myeloma using conventional whole-body MRI, spinal dynamic contrast-enhanced MRI, and spinal diffusion-weighted imaging

OBJECTIVES

Cytogenetic abnormalities are predictors of poor prognosis in multiple myeloma (MM). This paper aims to build and validate a multiparametric conventional and functional whole-body MRI-based prediction model for cytogenetic risk classification in newly diagnosed MM.

METHODS

Patients with newly diagnosed MM who underwent multiparametric conventional whole-body MRI, spinal dynamic contrast-enhanced (DCE-)MRI, spinal diffusion-weighted MRI (DWI) and had genetic analysis were retrospectively included (2011-2020/Ghent University Hospital/Belgium). Patients were stratified into standard versus intermediate/high cytogenetic risk groups. After segmentation, 303 MRI features were extracted. Univariate and model-based methods were evaluated for feature and model selection. Testing was performed using receiver operating characteristic (ROC) and precision-recall curves. Models comparing the performance for genetic risk classification of the entire MRI protocol and of all MRI sequences separately were evaluated, including all features. Four final models, including only the top three most predictive features, were evaluated.

RESULTS

Thirty-one patients were enrolled (mean age 66 ± 7 years, 15 men, 13 intermediate-/high-risk genetics). None of the univariate models and none of the models with all features included achieved good performance. The best performing model with only the three most predictive features and including all MRI sequences reached a ROC-area-under-the-curve of 0.80 and precision-recall-area-under-the-curve of 0.79. The highest statistical performance was reached when all three MRI sequences were combined (conventional whole-body MRI + DCE-MRI + DWI). Conventional MRI always outperformed the other sequences. DCE-MRI always outperformed DWI, except for specificity.

CONCLUSIONS

A multiparametric MRI-based model has a better performance in the noninvasive prediction of high-risk cytogenetics in newly diagnosed MM than conventional MRI alone.

CRITICAL RELEVANCE STATEMENT

An elaborate multiparametric MRI-based model performs better than conventional MRI alone for the noninvasive prediction of high-risk cytogenetics in newly diagnosed multiple myeloma; this opens opportunities to assess genetic heterogeneity thus overcoming sampling bias.

KEY POINTS

• Standard genetic techniques in multiple myeloma patients suffer from sampling bias due to tumoral heterogeneity. • Multiparametric MRI noninvasively predicts genetic risk in multiple myeloma. • Combined conventional anatomical MRI, DCE-MRI, and DWI had the highest statistical performance to predict genetic risk. • Conventional MRI alone always outperformed DCE-MRI and DWI separately to predict genetic risk. DCE-MRI alone always outperformed DWI separately, except for the parameter specificity to predict genetic risk. • This multiparametric MRI-based genetic risk prediction model opens opportunities to noninvasively assess genetic heterogeneity thereby overcoming sampling bias in predicting genetic risk in multiple myeloma.

Whole-body magnetic resonance imaging (WBMRI) versus whole-body computed tomography (WBCT) for myeloma imaging and staging

Myeloma-associated bone disease (MBD) develops in about 80-90% of patients and severely affects their quality of life, as it accounts for the majority of mortality and morbidity. Imaging in multiple myeloma (MM) and MBD is of utmost importance in order to detect bone and bone marrow lesions as well as extraosseous soft-tissue masses and complications before the initiation of treatment. It is required for determination of the stage of disease and aids in the assessment of treatment response. Whole-body low-dose computed tomography (WBLDCT) is the key modality to establish the initial diagnosis of MM and is now recommended as reference standard procedure for the detection of lytic destruction in MBD. In contrast, whole-body magnetic resonance imaging (WBMRI) has higher sensitivity for the detection of focal and diffuse plasma cell infiltration patterns of the bone marrow and identifies them prior to osteolytic destruction. It is recommended for the evaluation of spinal and vertebral lesions, while functional, diffusion-weighted MRI (DWI-MRI) is a promising tool for the assessment of treatment response. This review addresses the current improvements and limitations of WBCT and WBMRI for diagnosis and staging in MM, underlining the fact that both modalities offer complementary information. It further summarizes the corresponding radiological findings and novel technological aspects of both modalities.

Recent Advances in the Management of Smoldering Multiple Myeloma

There is remarkable progress in the treatment of multiple myeloma (MM) with significant improvement in survival in the past 10 years. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) can evolve into symptomatic multiple myeloma (sy-MM) with organ involvement. SMM has associated with a much higher progression to MM compared to MGUS. In 2014, International Myeloma Working Group (IMWG) reclassified ultra-high-risk smoldering myeloma patients with bone marrow plasma cells > 60% or serum-free light chain ratio (FLCr) > 100 or > 1 focal bone lesion on the magnetic resonance imaging as MM. SMM is a heterogeneous disorder with probability for progression to myeloma up to 50% in the first 5 years. Several risk models and clinical features have been identified to stratify the risk of progression to MM. Thanks to advances in our understanding of the genomic profile of MM, there are several ongoing clinical trials, and genomic studies are being done to assess the risk of progression to MM and early intervention. There is still no standard criterion regarding when to start therapy. This review discusses identifying SMM patients who are at high risk of progression to sy-MM and recent development of new and early treatment strategies and ongoing clinical trials for these high-risk SMM patients.

Contrast agents in dynamic contrast-enhanced magnetic resonance imaging

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a noninvasive method to assess angiogenesis, which is widely used in clinical applications including diagnosis, monitoring therapy response and prognosis estimation in cancer patients. Contrast agents play a crucial role in DCE-MRI and should be carefully selected in order to improve accuracy in DCE-MRI examination. Over the past decades, there was much progress in the development of optimal contrast agents in DCE-MRI. In this review, we describe the recent research advances in this field and discuss properties of contrast agents, as well as their advantages and disadvantages. Finally, we discuss the research perspectives for improving this promising imaging method.

Prognostic Biomarkers in the Progression From MGUS to Multiple Myeloma: A Systematic Review

Multiple myeloma (MM), characterized by malignant plasma cells in the bone marrow, is consistently preceded by asymptomatic premalignant stage monoclonal gammopathy of undetermined significance (MGUS). These MGUS patients have an annual risk of 1% to progress to MM. Clinical, imaging, and genomic (genetic and epigenetic) factors were identified, whose presence increased the risk of progression from MGUS to MM. In this systematic review we summarize the currently identified clinical, imaging, and genomic biomarkers suggested to increase the progression risk or shown to be differentially expressed/present between both cohorts of patients. Despite the wide range of proposed markers, there are still no reliable biomarkers to individually predict which MGUS patient will progress to MM and which will not. Research on biomarkers in the progression from MGUS to MM will give more insight in the unknown pathogenesis of this hematological malignancy. This would improve research by elucidating new pathways and potential therapeutic targets as well as clinical management by closer follow-up and earlier treatment of high-risk MGUS patients.

Functional and molecular MRI of the bone marrow in multiple myeloma

MRI plays an important role in the management of patients with plasma cell neoplasms and has been recognized as a biomarker of malignancy in the novel criteria for the diagnosis of multiple myeloma. Functional and molecular MRI techniques such as diffusion-weighted imaging (spinal or whole body), intravoxel incoherent motion, and dynamic contrast enhanced MRI, provide additional information related to tumor cellularity and angiogenesis, which may have prognostic implications for patients with smoldering and symptomatic myeloma. These non-invasive functional techniques are also being evaluated as imaging biomarkers for response assessment in myeloma patients. The purpose of this article is to provide a comprehensive critical review on the current use and potential future applications of these advanced MRI techniques in multiple myeloma. In addition, we will address the technologies involved and describe the qualitative and quantitative characteristics of normal bone marrow with these techniques.

Dynamic contrast-enhanced magnetic resonance imaging parameters correlate with advanced revised-ISS and angiopoietin-1/angiopoietin-2 ratio in patients with multiple myeloma

The aim of the study was to assess the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with newly diagnosed multiple myeloma (MM) who were treated with novel anti-myeloma agents. We studied 60 previously untreated MM patients at diagnosis, 14 with smoldering MM (SMM) and 5 with MGUS. All patients underwent MRI of the thoracolumbar spine and pelvis before the administration of any kind of therapy, and DCE-MRI was performed. The MRI perfusion parameters evaluated were wash-in (WIN), washout (WOUT), time-to-peak (TTPK), time-to-maximum slope (TMSP), and the WIN/TMSP ratio. The following serum levels of angiogenic cytokines were measured on the day of MRI: VEGF, angiogenin (Ang), angiopoietin-1 (Angp-1), and -2 (Angp-2). Symptomatic MM patients had increased WIN compared to SMM (p < 0.05) and MGUS patients (p = 0.001). TTPK was decreased, and WIN/TMSP was increased in both symptomatic and SMM patients compared to MGUS patients (p < 0.05). Symptomatic MM patients had decreased TMSP compared to MGUS patients. The Angp-1/Angp-2 ratio was reduced in symptomatic MM compared to SMM (p = 0.017) and MGUS patients (p < 0.001). TTPK correlated with Angp-1/Angp-2 ratio and importantly with R-ISS. Patients with R-ISS-3 had lower TTPK median value (23 s, range 18-29 s) compared to patients with R-ISS-2 (48 s, range 27-68 s) and patients with R-ISS-1 MM (54 s, range 42-76 s; p ANOVA = 0.01). A subset of patients with low TTPK (lower quartile) had shorter time to progression compared to all other patients. These data suggest that certain DCE-MRI parameters correlate with R-ISS and adverse prognostic features of angiogenesis, such as the ratio of Angp-1/Angp-2.

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.

The Role of Imaging in the Treatment of Patients With Multiple Myeloma in 2016

The novel criteria for the diagnosis of symptomatic multiple myeloma have revealed the value of modern imaging for the management of patients with myeloma. Whole-body low-dose CT (LDCT) has increased sensitivity over conventional radiography for the detection of osteolytic lesions, and several myeloma organizations and institutions have suggested that whole-body LDCT should replace conventional radiography for the work-up of patients with myeloma. MRI is the best imaging method for the depiction of marrow infiltration by myeloma cells. Whole-body MRI (or at least MRI of the spine and pelvis if whole-body MRI is not available) should be performed for all patients with smoldering multiple myeloma with no lytic lesions to look for occult disease, which may justify treatment. In addition, MRI accurately illustrates the presence of plasmacytomas, spinal cord, and/or nerve compression for surgical intervention or radiation therapy; it is also recommended for the work-up of solitary bone plasmacytoma, and it may distinguish malignant from benign fractures (which is very important in cases of patients in biochemical remission with no other signs of progression). Diffusion weighted imaging (DWI) seems to improve MRI diagnosis in patients with myeloma. PET/CT is a functional imaging technique, more sensitive than conventional radiography for the detection of lytic lesions, which probably allows better definition of complete response and minimal residual disease compared with all other imaging methods. PET/CT has shown the best results in the follow-up of patients with myeloma and has an independent prognostic value both at diagnosis and following treatment. PET/CT can also be used for the work-up of solitary bone plasmacytoma and nonsecretory myeloma.

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.

Increased microcirculation detected by dynamic contrast-enhanced magnetic resonance imaging is of prognostic significance in asymptomatic myeloma

This prospective study aimed to investigate the prognostic significance of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) as a non-invasive imaging technique delivering the quantitative parameters amplitude A (reflecting blood volume) and exchange rate constant kep (reflecting vascular permeability) in patients with asymptomatic monoclonal plasma cell diseases. We analysed DCE-MRI parameters in 33 healthy controls and 148 patients with monoclonal gammopathy of undetermined significance (MGUS) or smouldering multiple myeloma (SMM) according to the 2003 IMWG guidelines. All individuals underwent standardized DCE-MRI of the lumbar spine. Regions of interest were drawn manually on T1-weighted images encompassing the bone marrow of each of the 5 lumbar vertebrae sparing the vertebral vessel. Prognostic significance for median of amplitude A (univariate: P < 0·001, hazard ratio (HR) 2·42, multivariate P = 0·02, HR 2·7) and exchange rate constant kep (univariate P = 0·03, HR 1·92, multivariate P = 0·46, HR 1·5) for time to progression of 79 patients with SMM was found. Patients with amplitude A above the optimal cut-off point of 0·89 arbitrary units had a 2-year progression rate into symptomatic disease of 80%. In conclusion, DCE-MRI parameters are of prognostic significance for time to progression in patients with SMM but not in individuals with MGUS.

Differentiation of tuberculosis and metastatic cancer in the spine using dynamic contrast-enhanced MRI

PURPOSE

To investigate the differences between imaging features of spinal tuberculosis (TB) and metastatic cancer measured by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The presentation of TB on convention MRI may not show the typical TB signs, and they may be mis-diagnosed as malignant diseases. DCE-MRI may provide additional information to help making differential diagnosis.

MATERIALS AND METHODS

DCE-MRI was performed in 24 TB and 22 metastatic cancer patients. The DCE kinetic pattern was determined as "wash-out", "plateau" or "persistent enhancement". The characteristic DCE parameters were calculated from the signal intensity time course. The two-compartmental pharmacokinetic model was used to obtain K (trans), which is the parameter associated with the delivery of MR contrast agents into the lesion, and k ep, which is the parameter associated with the distribution and clearance of contrast agents from the lesion.

RESULTS

Of the 24 TB, one case showed the wash-out kinetic pattern, 12 cases showed the plateau pattern, and 11 cases showed the persistent enhancement pattern. Of the 22 metastatic cancers, 12 cases showed wash-out, 7 cases showed plateau, and 3 cases showed persistent enhancement patterns. Compared to the metastatic cancer group, the TB group had a lower k ep (0.27 ± 0.15 vs. 0.49 ± 0.23 min(-1), P < 0.001). The ROC analysis showed that the area under the curve was 0.780 for k ep.

CONCLUSIONS

DCE-MRI may provide additional information for differentiation between spinal TB and metastasis, when their manifestations on conventional imaging were similar.

[Imaging in smoldering (asymptomatic) multiple myeloma. Past, present and future]

CLINICAL ISSUE

Emerging clinical trial data support treatment of high-risk smoldering multiple myeloma (SMM) upon diagnosis, and not only at the time of progression to symptomatic complications (multiple myeloma). Early detection of bone and/or bone marrow involvement by sensitive imaging modalities may help define SMM patients at a high risk of progression.

STANDARD RADIOLOGICAL METHODS

Current (2011) consensus guidelines recognize skeletal survey as a cornerstone modality for assessment of bone involvement at initial diagnosis and during follow-up of SMM. Skeletal survey has severe limitations related to underdetection of bone lesions and also provides no information on bone marrow abnormalities.

METHODICAL INNOVATIONS

Modern imaging strategies such as fluorodeoxyglucose positron-emission tomography/CT (FDG PET/CT) and MRI, in conjunction with functional innovations, provide improved estimates of global abnormalities in the bone marrow and bone compartments. These methods have the potential to objectively quantify early transformation from SMM to multiple myeloma.

PERFORMANCE

Although frequently used for staging and risk prognostication in multiple myeloma, modern imaging techniques have only been evaluated to a limited extent in SMM. Scant data in SMM indicate the prognostic value of two or more MRI-detected focal bone marrow abnormalities, which, if present, predict rapid progression to multiple myeloma. Data evaluating the role of FDG PET/CT in detecting early bone marrow abnormalities as an aid to predicting risk or directing treatment in SMM is currently lacking.

ACHIEVEMENTS

The superior specificity and sensitivity of modern imaging techniques compared to skeletal survey suggest that these should have a place in standard practice management of patients at a high risk of SMM progression. The model imaging of the future should be an all-in-one strategy offering high diagnostic performance for bone marrow abnormalities and low-volume bone lesions, as well as allowing monitoring by minimizing radiation exposure and the need for contrast agents.

PRACTICAL RECOMMENDATIONS

Newer imaging techniques need to be validated in prospective clinical trials assessing the SMM to multiple myeloma transition, with the aim of enabling appropriate management decisions. Efforts are also needed to improve the costs and availability of whole-body MRI and/or FDG PET/CT, in order to facilitate their widespread adoption as first-line detection modalities. Future clinical trials of therapeutic agents using earlier detection strategies will have to be carefully designed and take into consideration the risk of lead-time and length-time biases, which might falsely demonstrate longer overall survival. The English full text version of this article is available at SpringerLink (under "Supplemental").

The application of Gadopentate-Dimeneglumin has no impact on progression free and overall survival as well as renal function in patients with monoclonal plasma cell disorders if general precautions are taken

OBJECTIVES

The current analysis investigated the prognostic significance of gadopentetate dimeglumine on survival and renal function in patients with monoclonal plasma cell disorders.

METHODS

In this study 263 patients who had received gadopentetate dimeglumine within a prospective trial investigating dynamic contrast-enhanced magnetic resonance imaging (MRI) were compared with 335 patients who had undergone routine, unenhanced MRI.

RESULTS

We found no significant prognostic impact of the application of contrast agent on progression-free survival in patients with either monoclonal gammopathy of undetermined significance, smouldering or symptomatic myeloma and no significant prognostic impact on overall survival in patients with symptomatic myeloma. Since renal impairment is a frequent complication of myeloma, and decreased renal function is associated with a higher risk of complications in patients receiving contrast agents, we evaluated the impact of contrast agent on renal function after 1 year. In the present analysis the only significant adverse impact on kidney function occurred in symptomatic myeloma patients who already had impaired renal parameters at baseline. Here, the renal function did not recover during therapy, whereas it did so in patients with normal or only slightly impaired renal function.

CONCLUSION

If general recommendations are adhered to, gadopentetate dimeglumine can be safely applied in patients with monoclonal plasma cell disease.

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.

Imaging of multiple myeloma: Current concepts

Medical imaging is of crucial importance for diagnosis and initial staging as well as for differentiation of multiple myeloma (MM) from other monoclonal plasma cell diseases. Conventional radiography represents the reference standard for diagnosis of MM due to its wide availability and low costs despite its known limitations such as low sensitivity, limited specificity and its inability to detect extraosseous lesions. Besides conventional radiography, newer cross-sectional imaging modalities such as whole-body low-dose computed tomography (CT), whole-body magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT are available for the diagnosis of osseous and extraosseous manifestations of MM. Whole-body low-dose CT is used increasingly, replacing conventional radiography at selected centers, due to its higher sensitivity for the detection of osseous lesions and its ability to diagnose extraosseous lesions. The highest sensitivity for both detection of bone marrow disease and extraosseous lesions can be achieved with whole-body MRI and ¹⁸F-FDG PET/CT. According to current evidence, MRI is the most sensitive method for initial staging while ¹⁸F-FDG PET/CT allows monitoring of treatment of MM. There is an evolving role for assessment of treatment response using newer MR imaging techniques. Future studies are needed to further define the exact role of the different imaging modalities for individual risk stratification and therapy monitoring.

The role of positron emission tomography-computed tomography and magnetic resonance imaging in diagnosis and follow up of multiple myeloma

Multiple myeloma is the second most common hematologic malignancy and occurs most commonly in elderly patients. Almost all multiple myeloma patients develop bone lesions in the course of their disease or have evidence of bone loss at initial diagnosis. Whole-body conventional radiography remains the gold standard in the diagnostic evaluation, but computed tomography, magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography are increasingly used as complementary techniques in the detection of bone lesions. Moreover, the number of lesions detected and the presence of extramedullary disease give strong prognostic information. These new techniques may help to assess treatment response in solitary plasmacytoma or in multiple myeloma. In this article, we review recent data on the different imaging techniques used at diagnosis and in the assessment of treatment response, and discuss some current issues.

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.

Role of dynamic contrast-enhanced sonography for characterization and monitoring of extramedullary myeloma: comparison with serologic data

OBJECTIVE

To measure blood perfusion in extramedullary myeloma by contrast-enhanced sonography, correlate it with specific hematologic parameters, and determine their utility for local and systemic response monitoring.

METHODS

Twenty-five consecutive patients (14 male and 11 female; median age, 68 years) with extramedullary myeloma were included. After intravenous administration of 2.4 mL of sulfur hexafluoride, extramedullary myeloma masses were examined for 60 seconds. All patients underwent contrast-enhanced sonography at baseline, and 15 were monitored additionally (3 weeks during therapy). Average peak perfusion, regional blood flow (RBF), and regional blood volume (RBV) were calculated. Baseline perfusion parameters were compared with short-term follow-up sonographic data and serologic biomarkers (M gradient). For validation of extramedullary myeloma and systemic myeloma, patients underwent midterm (<3 months) imaging and serologic diagnosis.

RESULTS

Patients with baseline β2-microglobulin (B2M) greater than 3.5 mg/L (n = 17) showed higher perfusion parameters compared with baseline B2M less than 3.5 mg/L (n = 8). At short-term follow-up, patients were classified by serologic criteria as responders (n = 9) and nonresponders (n = 6) and by sonographic criteria as responders (n = 10) and nonresponders (n = 5). In sonographic responders, mean peak, RBV, and RBF dropped from 59.13, 1446.09, and 71.52 (artificial units) at baseline to 29.30, 364.19, and 34.64 at follow-up (P < .05), whereas in nonresponders, perfusion parameters increased from 33.18, 789.82, and 36.92 at baseline to 51.14, 1491.06, and 65.34 at follow-up (P > .05). Prediction of a midterm course of systemic myeloma using serologic data yielded sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 0.66, 0.77, 0.66, and 0.77, whereas sonographic results (judged by RBV) yielded values of 0.66, 0.55, 0.5, and 0.71. Separate prediction of a local (extramedullary myeloma) response by sonography yielded sensitivity, specificity, PPV, and NPV of 0.8, 1.0, 1.0, and 0.71.

CONCLUSIONS

Contrast-enhanced sonography is a valuable tool for short-term monitoring of the treatment response in extramedullary myeloma.

Osteoporosis influences osteogenic but not angiogenic response during bone defect healing in a rat model

Angiogenesis is pivotal for bone metabolism and bone defect healing. Yet the role of vascularization in osteoporosis and osteoporotic bone repair mechanisms is unclear. Here we investigated effects of osteoporotic phenotype on vascularization during bone defect healing in a rodent osteotomy model using volumetric computed tomography (VCT), dynamic contrast-enhanced VCT (DCE-VCT), dynamic contrast-enhanced MRI (DCE-MRI) and histology. In 16 rats, 8 with physiological bone status (SHAM) and 8 with osteoporotic bone status induced by ovariectomy (OVX) in combination with a vitamin D- and low calcium diet, wedge-shaped defects were created at the left distal femur and stabilized internally by T-shaped miniplate. MRI and VCT were performed in all animals 6 weeks after this procedure. By VCT, relative bone density in the defect was evaluated. Using DCE-VCT and DCE-MRI, parameters associated with regional blood volume were calculated in the bone defect, vicinity of the defect, surrounding muscles and bone marrow: Amplitude A and exchange rate constant Kep (DCE-MRI, respectively) as well as peak enhancement PE and area under the curve AUC (DCE-VCT, respectively). In animals of osteoporotic phenotype, bone density within the osseous defect was significantly reduced as compared to SHAM rats. Vascularization parameters determined by DCE-MRI and DCE-VCT in the defect were significantly elevated compared to the adjacent tissues for both SHAM and OVX groups. However, comparing SHAM and OVX rats, no statistically different values were found by DCE-MRI and DCE-VCT concerning any determined vascularization parameter within the bone defect. Furthermore, parameters of vascularization were increased for OVX as compared to SHAM rats within the bone marrow although significant difference was only found for A. In a rat osteotomy model we showed that at the reparative healing stage, osteoporotic phenotype did influence osteogenic but not angiogenic response within bone defect as imaged by DCE-MRI and DCE-VCT. This study provides insight into the relationship between angiogenesis and osteogenesis during osteoporosis-related compromised bone healing.

Value of whole body MRI and dynamic contrast enhanced MRI in the diagnosis, follow-up and evaluation of disease activity and extent in multiple myeloma

PURPOSE

To evaluate the significance of dynamic contrast enhanced MRI (DCE-MRI) and whole body MRI (WB-MRI) in the diagnosis, prognosis and assessment of therapy for patients with monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM).

MATERIALS AND METHODS

The retrospective study includes 219 patients providing 463 WB-MRI and DCE-MRI investigations for the subgroups MGUS (n=70), MM active disease (n=126; this includes 70 patients with new diagnosis of MM, according to the International Staging System (ISS): 41.4% ISS stage I, 20.0% ISS stage II, 7.1% ISS stage III, 31.4% insufficient for staging; and 56 patients with '(re-)active disease': 16.07% relapse, 32.14% progressive disease and 51.79% stable disease) and MM remission (n=23; 60.87% complete remission, 17.39% very good partial remission and 21.74% partial remission). Investigations of patients with hereditary multiple exostoses (n=5), neurofibromatosis (n=7) and healthy persons (n=9) were added as control subjects (n=21). WB-MRI evaluation was done by evaluating thirteen skeletal regions, providing a 'skeletal score'. DCE-MRI images of the spine, were analyzed with regions-of-interest and time-intensity-curves (TIC).

RESULTS

All TIC parameters can significantly differentiate between the predefined subgroups (p<0.001). One hundred days after autologous stem cell transplantation a 75% decrease of the slope wash-in value (p<0.001) can be seen. A cubic regression trend between 'skeletal score' and slope wash-in (adj.R(2)=0.412) could demonstrate a significant increase bone marrow perfusion if MM affects more than 10 skeletal regions (p<0.001), associated with a poorer prognosis (p<0.001).

CONCLUSION

DCE-MRI evaluation of the spine is useful for diagnosis of MM, follow-up after stem cell transplantation and evaluation of disease activity. A combined evaluation with WB-MRI and DCE-MRI provides additional micro-vascular information on the morphologic lesions and could help categorize patients with MM in two different groups to offer useful therapeutic and prognostic advise.

Differentiation of myeloma and metastatic cancer in the spine using dynamic contrast-enhanced MRI

Spinal myeloma and metastatic cancer cause similar symptoms and show similar imaging presentations, thus making them difficult to differentiate. In this study, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed to differentiate between 9 myelomas and 22 metastatic cancers that present as focal lesions in the spine. The characteristic DCE parameters, including the peak signal enhancement percentage (SE%), the steepest wash-in SE% during the ascending phase and the wash-out SE%, were calculated by normalizing to the precontrast signal intensity. The two-compartmental pharmacokinetic model was used to obtain K(trans) and kep. All nine myelomas showed the wash-out DCE pattern. Of the 22 metastatic cancers, 12 showed wash-out, 7 showed plateau, and 3 showed persistent enhancing patterns. The fraction of cases that showed the wash-out pattern was significantly higher in the myeloma group than the metastatic cancer group (9/9=100% vs. 12/22=55%, P=.03). Compared to the metastatic cancer group, the myeloma group had a higher peak SE% (226%±72% vs. 165%±60%, P=.044), a higher steepest wash-in SE% (169%±51% vs. 111%±41%, P=.01), a higher K(trans) (0.114±0.036 vs. 0.077±0.0281/min, P=.016) and a higher kep (0.88±0.26 vs. 0.49±0.23 1/min, P=.002). The receiver operating characteristic analysis to differentiate between these two groups showed that the area under the curve was 0.798 for K(trans), 0.864 for kep and 0.919 for combined K(trans) and kep. These results show that DCE-MRI may provide additional information for making differential diagnosis to aid in choosing the optimal subsequent procedures or treatments for spinal lesions.

Parametric histogram analysis of dynamic contrast-enhanced MRI in multiple myeloma: a technique to evaluate angiogenic response to therapy?

RATIONALE AND OBJECTIVES

From dynamic contrast-enhanced magnetic resonance imaging, it is known that microcirculation patterns in multiple myeloma differ depending on the infiltration pattern. The purpose of this study was to evaluate histogram analysis of dynamic contrast-enhanced magnetic resonance imaging in MM to monitor early treatment response on the basis of microcirculation patterns.

MATERIALS AND METHODS

A total of 51 patients with multiple myeloma requiring therapy were examined. Dynamic contrast-enhanced magnetic resonance imaging of the lumbar spine was performed before and after conventional or high-dose chemotherapy with autologous stem cell transplantation. Statistical analysis included 245 vertebrae and dynamic microcirculation parameters as displayed in histograms. Resulting parameters (amplitude, exchange rate constant, skewness, kurtosis, and left shift) were correlated with therapeutic response.

RESULTS

More than 70% of histograms derived from the microcirculation parameters showed a difference between the maximum peak before and after therapy (left shift). However, there was no significant difference between the particular treatment. Significantly different skewness of amplitude in 98% and kurtosis of exchange rate constant (94.1% and 98%) were seen in the patients who responded to treatment (P for each < .05).

CONCLUSIONS

Histogram analysis revealed early changes after therapy resulting in a shift toward more (kurtosis) and lower values (skewness) of microcirculation parameters. Therefore, histogram analysis can determine and describe if a chosen therapy works at all. However, there were no differences between the chosen therapies. This needs to be reevaluated in a larger number of treated patients. Histogram analysis can also be an adjunct to a subjective visual analysis but is hampered by heterogeneous infiltration pattern seen in multiple myeloma.

Current and future imaging modalities for multiple myeloma and its precursor states

Traditionally, the skeletal survey has been the standard modality for the detection of osteolytic bone disease in multiple myeloma. In addition to its poor sensitivity for the detection of osteolytic lesions, this modality is not able to identify extramedullary lesions and focal bone marrow involvement, nor measure response to therapy. The application of novel imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), and molecular imaging such as fluorine-18 fluorodeoxyglucose positron emission tomography CT ((18)F-FDG PET/CT) and fluorine-18 sodium fluoride positron emission tomography CT ((18)F-NaF PET/CT) has the potential to overcome these limitations as well as provide prognostic information in precursor states and multiple myeloma. Also promising is the use of dynamic contrast enhanced magnetic resonance imaging (DCE MRI) to measure vascular permeability, an important feature of myelomagenesis. This review summarizes the current status and possible future role of novel imaging modalities in multiple myeloma and its precursor states.

Molecular imaging in myeloma precursor disease

Multiple myeloma (MM) is consistently preceded by its pre-malignant states, monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering multiple myeloma (SMM). By definition, precursor conditions do not exhibit end-organ disease (anemia, hypercalcemia, renal failure, skeletal lytic lesions, or a combination of these). However, new imaging methods are demonstrating that some patients in the MGUS or SMM category are exhibiting early signs of MM. Although MGUS/SMM patients are currently defined as low-risk versus high-risk based on clinical markers, we currently lack the ability to predict the individual patient's risk of progression from MGUS/SMM to MM. Given that the presence of gross lytic bone lesions is a hallmark of MM, it is reasonable to believe that less severe bone changes defined by more sensitive imaging may be predictive of MM progression. Indeed, since bone disease is such an essential aspect of MM, imaging techniques directed at the detection of early bone lesions, have the potential to become increasingly more useful in the setting of MGUS/SMM. Current guidelines for the radiological assessment of MM still recommend the traditional skeletal survey, although its limitations are well documented, especially in early phases of the disease when radiographs can significantly underestimate the extent of bone lesions and bone marrow involvement. Newer, more advanced imaging modalities, with higher sensitivities, including whole-body low-dose computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are being employed. Also various imaging techniques have been used to provide an assessment of bone involvement and identify extra-osseous disease. This review emphasizes the current state of the art and emerging imaging methods, which may help to better define high-risk versus low-risk MGUS/SMM. Ultimately, improved imaging could allow more tailored clinical management, and, most likely play an important role in the development of future treatment strategies for high-risk precursor disease.

Myelomagenesis: capturing early microenvironment changes

Plasma cell neoplasms result from the clonal expansion of terminally differentiated, immunoglobulin heavy-chain class switched B cells that typically secrete a monoclonal immunoglobulin. The 2008 World Health Organization (WHO) classification of plasma cell neoplasms encompasses a broad spectrum of disorders, from the precursor disorder monoclonal gammopathy of undetermined significance (MGUS) to plasma cell leukemia. The classification includes, in addition to precursor lesion MGUS, plasma cell myeloma, plasmacytoma, immunoglobulin deposition diseases, and osteosclerotic myeloma. Plasma cell myeloma is further divided into symptomatic plasma cell myeloma or multiple myeloma (MM), asymptomatic smoldering myeloma (SMM), non-secretory myeloma, and plasma cell leukemia. Although histopathologic cut-off criteria are incorporated into the classification schema, distinction between MGUS, SMM, and MM depends primarily on the presence or absence of end-organ damage, as defined by "CRAB" criteria (hypercalcemia, renal insufficiency, anemia, lytic bone lesions, or a combination of these). Systematic evaluation of pathogenetic differences between MGUS and MM should offer invaluable insights into early myelomagenesis. Given the complex, intertwined nature of the malignant plasma cell and its surroundings, multiple pathogenetic mechanisms play a critical role in interactions between neoplastic cells and their microenvironment. Understanding the events leading to end-organ damage, like anemia and bone remodeling, is a critical part of investigating early myelomagenesis and should provide us with better tools for early identification and treatment of these patients.

Bone disease in multiple myeloma and precursor disease: novel diagnostic approaches and implications on clinical management

The manifestations of bone involvement in patients with multiple myeloma (MM) can have devastating clinical effects and increase mortality. Recent studies demonstrate that patients with the precursor conditions smoldering MM (SMM) and monoclonal gammopathy of undetermined significance (MGUS) show evidence of bone disease and increased risk of fractures. The understanding of the pathogenesis of bone disease in MM has expanded in recent years. The traditional skeletal survey will probably be replaced by newer and more sensitive imaging techniques, which may have a prognostic impact and change our definition of MGUS and SMM. Bisphosphonates are recommended to prevent skeletal events in patients with MM, and have also been studied in SMM and MGUS. This article summarizes the current knowledge of bone disease in plasma cell disorders, and discusses the current standard and future role of novel imaging techniques, as well as the evidence and current guidelines for bisphosphonates in MM, SMM and MGUS.

Patterns of monoclonal immunoglobulins and serum free light chains are significantly different in black compared to white monoclonal gammopathy of undetermined significance (MGUS) patients

Monoclonal gammopathy of undetermined significance (MGUS), the precursor to multiple myeloma, is more common in blacks than whites. The serum free light chain (sFLC) assay is an important prognostic test in MGUS, but no study has evaluated sFLC levels and ratios in black MGUS patients. One-hundred and twenty-five black MGUS patients at two urban centers were compared to the white population of the Mayo Clinic. The median age for blacks was 73 years [41-94] and 75% were male. The M-protein isotype in blacks was 81% IgG, 13% IgA, 2% IgM, and 4% biclonal compared to 70%, 12%, 16%, and 2%, respectively, in whites, (P < 0.0005). The median M-protein concentration for blacks was 0.44 gm/dL (trace-2.33) compared to 1.2 gm/dl in whites. An abnormal sFLC ratio was present in 45% of black compared to 33% of white (P = 0.01) patients. Using the Mayo Clinic risk model, black patients had a significantly lower proportion of higher risk MGUS compared to whites: low 43%, low-intermediate 45%, high-intermediate 10%, and high 2% (P = 0.014). Black patients with MGUS have significantly different laboratory findings compared to whites. The biologic basis for these disparities and their effect on prognostic assessment is unknown. Prognostic models based on these biomarkers should be used cautiously in nonwhite populations.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging of bone marrow in healthy individuals

BACKGROUND

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) displays microcirculation and permeability by application of contrast-media and diffusion-weighted imaging (DWI) is a tool for quantification of cellularity in the investigated area. Recently published examples cover breast cancer, CNS tumors, head and neck cancer, gastrointestinal cancer, prostate cancer as well as hematologic malignancies.

PURPOSE

To investigated the influence of age, sex, and localization of the investigated region on findings of DCE-MRI and DWI.

MATERIAL AND METHODS

DCE-MRI-parameters amplitude A and exchange rate constant kep as well as the DWI-parameter ADC of the bone marrow of the lumbar vertebral column of 30 healthy individuals covering the typical range of age of tumor patients were evaluated. ADC was calculated using b=0 and a maximal b value of either 400 or 750 s/mm(2).

RESULTS

Amplitude A of DCE-MRI decreased with age (P = 0.01) and amplitude A, exchange rate constant kep as well as ADC based on b = 400 s/mm(2) and b = 750 s/mm(2,) respectively, decreased significantly from the first to the fifth lumbar vertebra with P = 0.02, P = 0.05, P = 0.003, and P = 0.002, respectively.

CONCLUSION

Quantitative parameters of functional imaging techniques in bone marrow are influenced by the age of the examined individual and the anatomical location of the investigated region.

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM): novel biological insights and development of early treatment strategies

Monoclonal gammopathy of unknown significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic plasma cell dyscrasias, with a propensity to progress to symptomatic MM. In recent years there have been improvements in risk stratification models (involving molecular markers) of both disorders, which have led to better understanding of the biology and probability of progression of MGUS and SMM. In the context of numerous molecular events and heterogeneous risk of progression, developing individualized risk profiles for patients with MGUS and SMM represents an ongoing challenge that has to be addressed by prospective clinical monitoring and extensive correlative science. In this review we discuss the current standard of care of patients with MGUS and SMM, the use of risk models, including flow cytometry and free-light chain analyses, for predicting risk of progression. Emerging evidence from molecular studies on MGUS and SMM, involving cytogenetics, gene-expression profiling, and microRNA as well as molecular imaging is described. Finally, future directions for improving individualized management of MGUS and SMM patients, as well as the potential for developing early treatment strategies designed to delay and prevent development of MM are discussed.

Tracer kinetic modelling of tumour angiogenesis based on dynamic contrast-enhanced CT and MRI measurements

PURPOSE

Technical developments in both magnetic resonance imaging (MRI) and computed tomography (CT) have helped to reduce scan times and expedited the development of dynamic contrast-enhanced (DCE) imaging techniques. Since the temporal change of the image signal following the administration of a diffusible, extracellular contrast agent (CA) is related to the local blood supply and the extravasation of the CA into the interstitial space, DCE imaging can be used to assess tissue microvasculature and microcirculation. It is the aim of this review to summarize the biophysical and tracer kinetic principles underlying this emerging imaging technique offering great potential for non-invasive characterization of tumour angiogenesis.

METHODS

In the first part, the relevant contrast mechanisms are presented that form the basis to relate signal variations measured by serial CT and MRI to local tissue concentrations of the administered CA. In the second part, the concepts most widely used for tracer kinetic modelling of concentration-time courses derived from measured DCE image data sets are described in a consistent and unified manner to highlight their particular structure and assumptions as well as the relationships among them. Finally, the concepts presented are exemplified by the analysis of representative DCE data as well as discussed with respect to present and future applications in cancer diagnosis and therapy.

RESULTS

Depending on the specific protocol used for the acquisition of DCE image data and the particular model applied for tracer kinetic analysis of the derived concentration-time courses, different aspects of tumour angiogenesis can be quantified in terms of well-defined physiological tissue parameters.

CONCLUSIONS

DCE imaging offers promising prospects for improved tumour diagnosis, individualization of cancer treatment as well as the evaluation of novel therapeutic concepts in preclinical and early-stage clinical trials.

Multiple myeloma precursor disease

Recent data indicate that multiple myeloma is consistently preceded by the precursor states of monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma. Currently, multiple myeloma is a clinical diagnosis based on manifestations including hypercalcemia, renal failure, anemia, and bone lesions, whereas MGUS and smoldering myeloma are diagnosed based on laboratory abnormalities. Current clinical markers allow for more individualized risk stratification and counseling of these patients. However, there is a dearth of biomarkers and molecular imaging techniques capable of (1) accurately identifying patients with disease biology corresponding with high risk of progression; (2) elucidating the mechanism of transformation to multiple myeloma; and (3) forming a framework for development of targeted therapies. This case presentation and review discusses the current understanding of myeloma precursor disease and future opportunities for improving personalized management of patients with MGUS or smoldering myeloma, as well as the potential for developing early treatment strategies designed to delay and prevent development of multiple myeloma.

Response assessment in patients with multiple myeloma during antiangiogenic therapy using arterial spin labeling and diffusion-weighted imaging: a feasibility study

RATIONALE AND OBJECTIVES

To determine whether response to anti-angiogenic therapy in patients with multiple myeloma can be assessed by noncontrast perfusion magnetic resonance imaging (MRI) (ie, arterial-spin-labeling [ASL]), and diffusion-weighted [DWI] MRI.

MATERIALS AND METHODS

The study protocol was approved by the local institutional ethic board. Ten consecutive patients (eight men, two women; mean age 60.5 ± 8.5 years) with Stage III multiple myeloma were prospectively included. MRI was performed at baseline, as well as 3 and 8 weeks after onset of antiangiogenic therapy. Functional MRI data were compared with clinical outcome and conventional lesion size and signal-intensity measurements. Differences between baseline and follow-up values for ASL-MRI and DWI-MRI were assessed using a paired Student t-test.

RESULTS

Nine patients responded well to therapy, whereas one patient was classified a nonresponder. Temporary changes in signal intensity between baseline and follow-up examinations were inconsistent on T1-weighted (w) and T2w images. Likewise, determination of lesion size at follow-up proved unreliable. ASL showed a marked decrease in perfusion from baseline (251 ± 159 mL/(min*100g)) to follow-up at 3 weeks (115 ± 85 mL/(min*100g), P = .01) and 8 weeks (101 ± 90 mL/(min*100g, P = .01), respectively. Relative to the baseline examination, mean diffusion increased from 0.68 ± 0.19 × 10(-3) s/mm(2) at baseline to 0.94 ± 0.24 × 10(-3) s/mm(2) after 3 weeks (P = .04), and 0.96 ± 0.40 × 10(-3) s/mm(2) after 8 weeks (P = .049). Both methods were able to correctly classify 9/10 patients as responder or nonresponder.

CONCLUSION

ASL perfusion as well as DWI-MRI provide accurate, clinically relevant information regarding tumor viability and can predict response already early after therapy onset, as opposed to classical lesion size and MRI signal-intensity measurements.

Molecular and biologic markers of progression in monoclonal gammopathy of undetermined significance to multiple myeloma

Multiple myeloma (MM) is a malignant plasma cell dyscrasia localized in the bone marrow. Recent studies have shown that MM is preceded in virtually all cases by a premalignant state called monoclonal gammopathy of undetermined significance (MGUS). This review focuses on non-IgM MGUS and its progression to MM. Although certain clinical markers of MGUS progression have been identified, it currently is not possible to accurately determine individual risk of progression. This review focuses on the various biologic and molecular markers that could be used to determine the risk of MM progression. A better understanding of the pathogenesis will allow us to define the biological high-risk precursor disease and, ultimately, to develop early intervention strategies designed to delay and prevent full-blown MM.

Smoldering (asymptomatic) multiple myeloma: revisiting the clinical dilemma and looking into the future

Recent studies show that multiple myeloma (MM) is consistently preceded by an asymptomatic precursor state. Smoldering MM (SMM) is a MM precursor defined by an M-protein concentration >or= 3 g/dL and/or >or= 10% bone marrow plasma cells, in the absence of end-organ damage. Compared with individuals diagnosed with monoclonal gammopathy of undetermined significance (MGUS), patients with SMM have a much higher annual risk of developing MM. However, based on clinical observations, the natural history of SMM varies greatly, from stable MGUS-like disease to highly progressive disease. Using conventional clinical markers, SMM patients can be stratified into 3 risk groups. Importantly, because of considerable molecular heterogeneity, we currently lack reliable markers to predict prognosis for individual SMM patients. Furthermore, until recently, potent drugs with reasonable toxicity profiles have not been available for the development of early MM treatment strategies. Consequently, current clinical guidelines emphasize the application of close clinical monitoring followed by treatment when the patient develops symptomatic MM. This review focuses on novel biomarkers, molecular profiles, and microenvironmental interactions of interest in myelomagenesis. We also discuss how the integration of novel biologic markers and clinical monitoring of SMM could facilitate the development of early treatment strategies for high-risk SMM patients in the future.

Beta-2-microglobulin is an independent predictor of progression in asymptomatic multiple myeloma

BACKGROUND

Although serum beta-2 microglobulin (B2M) represents a key variable for symptomatic multiple myeloma (MM) prognostication, its role in predicting the risk of progression of asymptomatic MM to symptomatic disease has not been explored.

METHODS

This study was bases on a consecutive series of 148 patients with asymptomatic MM and explored the cumulative probability of progression to symptomatic MM as the primary endpoint.

RESULTS

In univariate analysis, a serum B2M level >2.5 mg/L was associated with an increased probability of disease progression (5-year risk, 64.5%; P < .001) along with serum monoclonal component (sMC) (P < .001), urinary monoclonal component (uMC) (P < .001), and bone marrow plasma cells (BMPCs) (P < .001). In multivariate analysis, serum B2M was selected as an independent predictor of progression (hazard ratio, 3.30; P = .002). Serum B2M was combined with sMC, uMC, and BMPC to create a risk-stratification model based on 4 groups with different risk of progression: very low (5-year risk, 0%), low-intermediate (5-year risk, 19.6%), high-intermediate (5-year risk, 60.7%), and high (5-year risk, 80.7%). The model that included serum B2M along with sMC, uMC, and BMPC was able to predict disease progression better than the model that was based on sMC, uMC, and BMPC without serum B2M (C statistics, 0.760 vs 0.726).

CONCLUSIONS

The current results indicated that 1) serum B2M is an independent predictor of asymptomatic MM progression, and 2) serum B2M adds prognostic information when combined with the most widely used prognosticators of asymptomatic MM progression.

Multiple myeloma

Advances in the imaging and treatment of multiple myeloma have occurred over the past decade. This article summarises the current status and highlights how an understanding of both is necessary for optimum management.

Monoclonal gammopathy of undetermined significance and smoldering myeloma: new insights into pathophysiology and epidemiology

Routine screening for monoclonal gammopathy of undetermined significance (MGUS) is not indicated. Despite this fact, MGUS is a common finding in medical practice. Almost all individuals diagnosed with MGUS represent incidental cases diagnosed when physicians order serum protein electrophoresis, immunofixation, or both, as part of the work-up of a number of common symptoms and laboratory abnormalities. In the absence of reliable molecular predictors of outcome, the detection of an early precursor state typically imposes a complex situation for the patient and the responsible physician-usually, it leads to a lot of questions that lack clear answers. In the past years, several novel insights have been gained in the area of multiple myeloma (MM) precursor disease. This review focuses on results from recent investigations and discusses implications for diagnostic work-up, clinical management, and patient counseling. More specifically, it sheds light on the following commonly asked questions by patients and physicians: i) what is the risk of progression from precursor to full-blown MM, and are there ways to risk-stratify patients?; ii) is MM always preceded by a precursor state, and is there anything that could or should be done to delay or prevent progression?; and iii) why do some individuals develop MM precursor diseases, and is there a reason to screen the family?