A prospective comparison of 18F-fluorodeoxyglucose positron emission tomography-computed tomography, magnetic resonance imaging and whole-body planar radiographs in the assessment of bone disease in newly diagnosed multiple myeloma

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.

Myeloma today: Disease definitions and treatment advances

There have been major advances in the diagnosis, staging, risk-stratification, and management of multiple myeloma (MM). In addition to established CRAB (hypercalcemia, renal failure, anemia, and lytic bone lesions) features, new diagnostic criteria include three new biomarkers to diagnose the disease: bone marrow clonal plasmacytosis ≥60%, serum involved/uninvolved free light chain ratio ≥100, and >1 focal lesion on magnetic resonance imaging. MM can be classified into several subtypes based on baseline cytogenetics, and prognosis varies according to underlying cytogenetic abnormalities. A Revised International Staging System has been developed which combines markers of tumor burden (albumin, beta-2 microglobulin) with markers of aggressive disease biology (high-risk cytogenetics and elevated serum lactate dehydrogenase). Although the approach to therapy remains largely the same, the treatment options at every stage of the disease have changed. Carfilzomib, pomalidomide, panobinostat, daratumumab, elotuzumab, and ixazomib have been approved for the treatment of the disease. These drugs combined with older agents such as cyclophosphamide, dexamethasone, thalidomide, bortezomib, and lenalidomide dramatically increase the repertoire of regimens available for the treatment of MM. This review provides a concise overview of recent advances in MM, including updates to diagnostic criteria, staging, risk-stratification, and management.

Updated Diagnostic Criteria and Staging System for Multiple Myeloma

There has been remarkable progress made in the diagnosis and treatment of multiple myeloma (MM). The median survival of the disease has doubled as a result of several new active drugs. These advances have necessitated a revision of the disease definition and staging of MM. Until recently, MM was defined by the presence of end-organ damage, specifically hypercalcemia, renal failure, anemia, and bone lesions (CRAB features) that can be attributed to the clonal process. In 2014, the International Myeloma Working Group (IMWG) updated the diagnostic criteria for MM to add three specific biomarkers that can be used to diagnose the disease in patients who did not have CRAB features: clonal bone marrow plasma cells greater than or equal to 60%, serum free light chain (FLC) ratio greater than or equal to 100 provided involved FLC level is 100 mg/L or higher, or more than one focal lesion on MRI. In addition, the definition was revised to allow CT and PET-CT to diagnose MM bone disease. These changes enable early diagnosis and allow the initiation of effective therapy to prevent the development of end-organ damage for patients who are at the highest risk. A new staging system has been developed that incorporates high-risk cytogenetic abnormalities in addition to standard laboratory markers of prognosis.

Whole body diffusion weighted MRI--a new view of myeloma

The recent consensus statement from the International Myeloma Working Group has introduced the role of whole body (WB) magnetic resonance imaging (MRI) into the management pathway for patients with multiple myeloma. The speed, coverage and high sensitivity of WB diffusion weighted (DW)-MRI and the unique capability to quantify both burden of disease and response to treatment has led to increasing implementation at leading centres worldwide for imaging malignant marrow disease, both primary and metastatic. WB DW-MRI is likely to have a significant impact on management decisions and pathways for patients with multiple myeloma. This review will introduce the basic principles of DW-MRI, present current evidence for patients with myeloma and will discuss practicalities and exciting future applications.

Diagnostic and Prognostic Implications of Spine Magnetic Resonance Imaging at Diagnosis in Patients with Multiple Myeloma

PURPOSE

The aim of this study is to determine the diagnostic and prognostic role of baseline spinal magnetic resonance imaging (MRI) in patients with multiple myeloma.

MATERIALS AND METHODS

We enrolled patients newly diagnosed with multiple myeloma from 2004-2011 at a single center. Abnormal MRI findings that were not detected in radiographs have been analyzed and categorized as malignant compression fractures or extramedullary plasmacytoma. The bone marrow (BM) infiltration patterns on MRI have been classified into five categories.

RESULTS

A total of 113 patients with a median age of 65 years (range, 40 to 89 years) were enrolled in the study. Malignant compression fractures not detected in the bone survey were found in 26 patients (23.0%), including three patients (2.6%) with no related symptoms or signs. Extramedullary plasmacytoma was detected in 22 patients (19.5%), including 15 (13.3%) with epidural extension of the tumor. Of these 22 patients, 11 (50.0%) had no relevant symptoms or signs. The presence of malignant compression fractures did not influence overall survival; whereas non-epidural extramedullary plasmacytoma was associated with poor overall survival in the multivariate analysis (hazard ratio, 3.205; 95% confidence interval [CI], 1.430 to 9.845; p=0.042). During the follow-up for a median of 21 months (range, 1 to 91 months), overall survival with the mixed BM infiltrative pattern (median, 24.0 months; 95% CI, 22.9 to 25.1 months) was shorter than those with other patterns (median 56 months; 95% CI, 48.9 to 63.1 months; p=0.030).

CONCLUSION

These results indicate that spine MRI at the time of diagnosis is useful for detecting skeletal lesions and predicting the prognosis in patients with multiple myeloma.

Improvement of diagnostic confidence for detection of multiple myeloma involvement of the ribs by a new CT software generating rib unfolded images: Comparison with 5- and 1-mm axial images

OBJECTIVE

To investigate the performance of a new CT software generating rib unfolded images for improved detection of rib osteolyses in patients with multiple myeloma.

MATERIALS AND METHODS

One hundred sixteen patients who underwent whole-body reduced-dose multidetector computed tomography (WBRD-MDCT) for multiple myeloma diagnosis and during follow-up were retrospectively evaluated. Nonenhanced CT scans with 5- and 1-mm slice thickness were interpreted by two readers with focus on detection of rib involvement (location, number, fracture). Image analysis of "unfolded," 1-mm-based CT rib images was subsequently undertaken. We classified the number of lytic bone lesions into 0, 1, 2, <5, <10 and ≥10. For all three data sets the reading time was registered.

RESULTS

An approximated sum of 6,727 myeloma-related rib lesions was found. On a patient-based analysis, CT (5 mm), CT (1 mm) and CT (1 mm "unfolded rib") yielded a sensitivity, specificity and accuracy of 79.7/94.7/87.1, 88.1/93/90.5 and 98.3/96.5/97.4, respectively. In a lesion-based analysis, the sensitivity, specificity and accuracy of the three evaluations were 69.7/87.2/70.5, 79.8/55.9/78 and 96.5/89.7/96.1. Mean reading time for 5 mm/1 mm axial images and unfolded images was 178.7/215.1/90.8 s, respectively.

CONCLUSION

The generation of "unfolded rib" images improves detection of rib involvement in patients with multiple myeloma and significantly reduces reading time.

Assessing myeloma bone disease with whole-body diffusion-weighted imaging: comparison with x-ray skeletal survey by region and relationship with laboratory estimates of disease burden

AIM

To estimate and compare the extent of myeloma bone disease by skeletal region using whole-body diffusion-weighted imaging (WB-DWI) and skeletal survey (SS) and record interobserver agreement, and to investigate differences in imaging assessments of disease extent and apparent diffusion coefficient (ADC) between patients with pathological high versus low disease burden.

MATERIALS AND METHODS

Twenty patients with relapsed myeloma underwent WB-DWI and SS. Lesions were scored by number and size for each skeletal region by two independent observers using WB-DWI and SS. Observer scores, ADC, and ADC-defined volume of tumour-infiltrated marrow were compared between patients with high and low disease burden (assessed by serum paraproteins and marrow biopsy).

RESULTS

Observer scores were higher on WB-DWI than SS in every region (p<0.05) except the skull, with greater interobserver reliability in rating the whole skeleton (WB-DWI: ICC = 0.74, 95% CI: 0.443-0.886; SS: ICC = 0.44, 95% CI: 0.002-0.730) and individual body regions. WB-DWI scores were not significantly higher in patients with high versus low disease burden (observer 1: mean ± SD: 48.8 ± 7, 38.6 ± 14.5, observer 2: mean ± SD: 37.3 ± 13.5, 30.4 ± 15.5; p = 0.06, p = 0.35).

CONCLUSION

WB-DWI demonstrated more lesions than SS in all regions except the skull with greater interobserver agreement. Sensitivity is not a limiting factor when considering WB-DWI in the management pathway of patients with myeloma.

A magnetic resonance imaging-based prognostic scoring system to predict outcome in transplant-eligible patients with multiple myeloma

Diffuse and focal bone marrow infiltration patterns detected by magnetic resonance imaging have been shown to be of prognostic significance in all stages of monoclonal plasma cell disorders and have, therefore, been incorporated into the definition of the disease. The aim of this retrospective analysis was to develop a rapidly evaluable prognostic scoring system, incorporating the most significant information acquired from magnetic resonance imaging. Therefore, the impact of bone marrow infiltration patterns on progression-free and overall survival in 161 transplant-eligible myeloma patients was evaluated. Compared to salt and pepper/minimal diffuse infiltration, moderate/severe diffuse infiltration had a negative prognostic impact on both progression-free survival (P<0.001) and overall survival (P=0.003). More than 25 focal lesions on whole-body magnetic resonance imaging or more than seven on axial magnetic resonance imaging were associated with an adverse prognosis (progression-free survival: P=0.001/0.003 and overall survival: P=0.04/0.02). A magnetic resonance imaging-based prognostic scoring system, combining grouped diffuse and focal infiltration patterns, was formulated and is applicable to whole-body as well as axial magnetic resonance imaging. The score identified high-risk patients with median progression-free and overall survival of 23.4 and 55.9 months, respectively (whole-body-based). Multivariate analyses demonstrated that the magnetic resonance imaging-based prognostic score stage III (high-risk) and adverse cytogenetics are independent prognostic factors for both progression-free and overall survival (whole-body-based, progression-free survival: hazard ratio=3.65, P<0.001; overall survival: hazard ratio=5.19, P=0.005). In conclusion, we suggest a magnetic resonance imaging-based prognostic scoring system which is a robust, easy to assess and interpret parameter summarizing significant magnetic resonance imaging findings in transplant-eligible patients with multiple myeloma.

Role of Magnetic Resonance Imaging in the Management of Patients With Multiple Myeloma: A Consensus Statement

Purpose

The aim of International Myeloma Working Group was to develop practical recommendations for the use of magnetic resonance imaging (MRI) in multiple myeloma (MM).

Methods

An interdisciplinary panel of clinical experts on MM and myeloma bone disease developed recommendations for the value of MRI based on data published through March 2014.

Recommendations

MRI has high sensitivity for the early detection of marrow infiltration by myeloma cells compared with other radiographic methods. Thus, MRI detects bone involvement in patients with myeloma much earlier than the myeloma-related bone destruction, with no radiation exposure. It is the gold standard for the imaging of axial skeleton, for the evaluation of painful lesions, and for distinguishing benign versus malignant osteoporotic vertebral fractures. MRI has the ability to detect spinal cord or nerve compression and presence of soft tissue masses, and it is recommended for the workup of solitary bone plasmacytoma. Regarding smoldering or asymptomatic myeloma, all patients should undergo whole-body MRI (WB-MRI; or spine and pelvic MRI if WB-MRI is not available), and if they have > one focal lesion of a diameter > 5 mm, they should be considered to have symptomatic disease that requires therapy. In cases of equivocal small lesions, a second MRI should be performed after 3 to 6 months, and if there is progression on MRI, the patient should be treated as having symptomatic myeloma. MRI at diagnosis of symptomatic patients and after treatment (mainly after autologous stem-cell transplantation) provides prognostic information; however, to date, this does not change treatment selection.

[PET-CT for nuclear medicine diagnostics of multiple myeloma]

BACKGROUND

Functional or morphofunctional imaging modalities are used in myeloma patients for the diagnosis and therapy management within research protocols. Despite new staging criteria, which take into account the viability of a myeloma lesion, positron emission tomography (PET) is not used routinely.

OBJECTIVES

The impact of PET is therefore open. The role of PET and PET computed tomography (PET-CT) for the diagnosis and therapy management is discussed.

RESULTS

The use of PET with 18F-fluorodeoxyglucose (FDG) allows the measurement of viable myeloma lesions and correlates with the stage of disease. A negative FDG examination correlates with a better prognosis. Furthermore, the number of focal lesions as well as the whole functional volume of myeloma lesions in FDG have a prognostic impact. Several studies have demonstrated the impact of FDG for the assessment of therapy monitoring and show that FDG is an earlier indicator for therapy response as compared to magnetic resonance imaging (MRI). The CT component of the new hybrid systems allows the assessment of osteolytic lesions in CT and their viability in FDG. The combination of PET with an MRT scanner allows the simultaneous measurement of bone marrow infiltration, focal lesions and their viability.

CONCLUSION

The use of modern hybrid scanners, such as PET-CT and PET-MRT facilitates the simultaneous measurement of viable myeloma lesions, osteolytic lesions and bone marrow infiltration in the whole body; therefore, it is expected that these imaging modalities will play a greater role both in diagnosis and therapy management.

Multiple myeloma

This article presents a review of multiple myeloma, precursor states, and related plasma cell disorders. The clinical roles of fluorodeoxyglucose PET/computed tomography (CT) and the potential to improve the management of patients with multiple myeloma are discussed. The clinical and research data supporting the utility of PET/CT use in evaluating myeloma and other plasma cell dyscrasias continues to grow.

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.

International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma

This International Myeloma Working Group consensus updates the disease definition of multiple myeloma to include validated biomarkers in addition to existing requirements of attributable CRAB features (hypercalcaemia, renal failure, anaemia, and bone lesions). These changes are based on the identification of biomarkers associated with near inevitable development of CRAB features in patients who would otherwise be regarded as having smouldering multiple myeloma. A delay in application of the label of multiple myeloma and postponement of therapy could be detrimental to these patients. In addition to this change, we clarify and update the underlying laboratory and radiographic variables that fulfil the criteria for the presence of myeloma-defining CRAB features, and the histological and monoclonal protein requirements for the disease diagnosis. Finally, we provide specific metrics that new biomarkers should meet for inclusion in the disease definition. The International Myeloma Working Group recommends the implementation of these criteria in routine practice and in future clinical trials, and recommends that future studies analyse any differences in outcome that might occur as a result of the new disease definition.

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.

Identification of the potential risk factors for monoclonal gammopathy of undetermined significance of progression

BACKGROUNDS

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant plasma cell disorder. The etiology of MGUS progression remains unclear and is a current topic of investigation.

METHODS

This review summarizes the essential features of MGUS and the potential risk factors for MGUS of progression.

RESULTS

Many clinical studies have been conducted to identify the critical risk markers that play important roles in progression. Some clinical variables, such as immunophenotypic markers and cytogenetic changes, have been recognized as potential risk factors.

CONCLUSIONS

In this review, we discuss novel insights from recent studies of potential risk factors, and we propose future directions for clinical management and additional studies.

Infiltration patterns in monoclonal plasma cell disorders: correlation of magnetic resonance imaging with matched bone marrow histology

OBJECTIVES

To investigate how plasma cell infiltration patterns detected by MRI match the plasma cell distribution in bone marrow biopsy.

METHODS

We assessed 50 patients with monoclonal plasma cell disorders of all clinical stages. MRI infiltration pattern was compared with matched BM histology from the same anatomic region.

RESULTS

MRI revealed a minimal (n=11, 22%), focal (n=5, 10%), diffuse (n=14, 28%) and mixed (n=20, 40%) infiltration pattern. Diffuse MRI pattern was predominant in smoldering myeloma patients whereas the MRI patterns with "focal component" (i.e. focal and mixed) were most common in symptomatic myeloma (p<0.01). In histology an interstitial (n=13, 26%), nodular (n=23, 46%) and packed marrow (n=14, 28%) was found respectively. All three histological types of infiltration were observed in patients with diffuse and mixed MRI patterns. Minimal MRI pattern was found in all MGUS patients and was associated with an interstitial BM infiltration. In two patients with minimal MRI pattern an extensive micro-nodular BM infiltration was found in histology.

CONCLUSIONS

Infiltration patterns in MRI represent different histological growth patterns of plasma cells, but the MRI resolution is not sufficient to visualize micro-nodular aggregates of plasma cells.

International Myeloma Working Group consensus statement for the management, treatment, and supportive care of patients with myeloma not eligible for standard autologous stem-cell transplantation

PURPOSE

To provide an update on recent advances in the management of patients with multiple myeloma who are not eligible for autologous stem-cell transplantation.

METHODS

A comprehensive review of the literature on diagnostic criteria is provided, and treatment options and management of adverse events are summarized.

RESULTS

Patients with symptomatic disease and organ damage (ie, hypercalcemia, renal failure, anemia, or bone lesions) require immediate treatment. The International Staging System and chromosomal abnormalities identify high- and standard-risk patients. Proteasome inhibitors, immunomodulatory drugs, corticosteroids, and alkylating agents are the most active agents. The presence of concomitant diseases, frailty, or disability should be assessed and, if present, treated with reduced-dose approaches. Bone disease, renal damage, hematologic toxicities, infections, thromboembolism, and peripheral neuropathy are the most frequent disabling events requiring prompt and active supportive care.

CONCLUSION

These recommendations will help clinicians ensure the most appropriate care for patients with myeloma in everyday clinical practice.

The utility of newer imaging techniques as predictors of clinical outcomes in multiple myeloma

The 14th International Myeloma Workshop Kyoto, Japan, 3-7 April 2013 The International Myeloma Workshop (IMW) is a biannual meeting that gathers experts in multiple myeloma (MM) from all over the world and scientists interested in clinical and biological aspects of myeloma. The 2013 IMW was held in Kyoto, Japan and presented an interesting program with an appealing section on newer imaging techniques as predictor of outcome in asymptomatic and symptomatic MM. During the meeting, the importance of newer functional imaging techniques as new ways of assessing bone disease and the extent of marrow infiltration by myeloma cells was highlighted. This short meeting report will provide a review of new and/or functional imaging techniques, such as magnetic resonance imaging (MRI), both axial and whole body (WB-MRI), dynamic contrast enhanced (DCE) MRI, diffusion weighted imaging (DWI) and PET integrated with computed tomography.

Positive correlation between baseline PET or PET/CT findings and clinical parameters in multiple myeloma patients

Recently, positron emission tomography (PET) has been incorporated into a series of prospective studies as a predictor of outcomes in multiple myeloma (MM), and the number of (18)F-fluorodeoxuglucose (FDG)-avid focal lesions (FLs) and the intensity of tumor metabolism have been designated as important surrogate markers for predicting prognosis. Here, we compared initial clinical characteristics of MM patients with baseline PET parameters: the number of FLs and the maximum standardized uptake value (SUVmax). A total of 59 patients diagnosed with MM between August 2004 and February 2012 were reviewed. At diagnosis, 23 patients (40.0%) had ≤3 FLs, 11 patients (18.6%) 4-9 FLs, and 25 patients (42.4%) ≥10 FLs. The median SUVmax was 5.3 (range 0-24.3), and 40 patients (67.8%) showed a SUVmax >4. No clinical characteristics were significantly different between groups with a SUVmax ≤4 and a SUVmax >4. However, there were significant differences in several clinical indices between the FLs ≤3 and FLs >3 groups; elevated β2-microglobulin, elevated lactate dehydrogenase, anemia and more advanced disease by the Durie-Salmon stage corresponded to FLs >3 at baseline PET. Adverse baseline PET findings are positively correlated with prognostically relevant clinical parameters. Regarding PET parameters, FLs are more likely to be well correlated with disease aggressiveness and pathophysiology compared to SUVmax.

(11)C-acetate as a new biomarker for PET/CT in patients with multiple myeloma: initial staging and postinduction response assessment

PURPOSE

We investigated the potential value of (11)C-acetate (ACT) PET/CT in characterizing multiple myeloma (MM) compared with (18)F-FDG PET/CT. Bone marrow histological and whole-body (WB) MRI findings served as the reference standards.

METHODS

In this prospective study, 15 untreated MM patients (10 men and 5 women, age range 48-69 years) underwent dual-tracer (11)C-ACT and (18)F-FDG PET/CT and WB MRI for pretreatment staging, and 13 of them had repeated examinations after induction therapy. Diffuse and focal bone marrow uptake was assessed by visual and quantitative analyses, including measurement of the maximum standardized uptake value (SUVmax). Between-group differences and correlations were assessed with the Mann-Whitney U test and the Pearson test.

RESULTS

At staging, all 15 patients had diffuse myeloma involvement upon bone marrow examination with 30-90 % of plasma cell infiltrates. Diffuse infiltration was detected in all of them (100 %) using (11)C-ACT with a positive correlation between bone marrow uptake values and percentages of plasma cell infiltrates (r = +0.63, p=0.01). In contrast, a diagnosis of diffuse infiltration could be established using (18)F-FDG in only six patients (40 %). Focal lesions were shown in 13 patients on both (11)C-ACT PET/CT and WB MRI, and in 10 patients on (18)F-FDG PET/CT. Focal lesions demonstrated (11)C-ACT uptake with a mean SUVmax of 11.4 ± 3.3 (range 4.6-19.6, n=59), which was significantly higher than the (18)F-FDG uptake (mean SUVmax 6.6 ± 3.1, range 2.3-13.7, n=29; p<0.0001). After treatment, the diffuse bone marrow (11)C-ACT uptake showed a mean SUVmax reduction of 66 % in patients with at least a very good partial response versus 34 % in those with at most a partial response only (p=0.01).

CONCLUSION

PET/CT using (11)C-ACT as a biomarker showed a higher detection rate for both diffuse and focal myeloma lesions at diagnosis than using (18)F-FDG, and may be valuable for response assessment.

Soft-tissue extramedullary multiple myeloma prognosis is significantly worse in comparison to bone-related extramedullary relapse

Even in the era of new drugs, multiple myeloma patients with extramedullary relapse have a poor prognosis. Our goal was to analyze the frequency and outcome of extramedullary relapse occurring in relapsed multiple myeloma patients. In total, we analyzed the prognosis of 226 relapsed multiple myeloma patients treated between 2005 and 2008 and evaluated them for presence of extramedullary relapse. We found evidence of extramedullary relapse in 24% (55 of 226) of relapsed multiple myeloma patients. In 14% (32 of 226) of patients, the lesions were not adjacent to the bone, while extramedullary relapse adjacent to the bone was documented in 10% (23 of 226) of cases. Patients without extramedullary relapse had significantly longer overall survival than patients with extramedullary relapse (109 vs. 38 months; P<0.001). Moreover, patients with soft tissue-related extramedullary relapse had significantly poorer overall survival compared to bone-related extramedullary relapse patients (30 vs. 45 months; P=0.022). Also, overall survival from diagnosis was as low as five months for soft tissue-related extramedullary relapse patients when compared to 12 months overall survival for bone-related extramedullary relapse. This is the first study that shows a significant difference in prognosis for different types of extramedullary relapse. If the extramedullary myeloma infiltration was not bone-related, overall survival after relapse was extremely short (5 months).

Role of positron emission tomography/computed tomography in bone malignancies

This article presents an overview of positron emission tomography combined with computed tomography (PET/CT) imaging of bone tumors for the practicing radiologist. The clinical roles and utility of (18)F-labeled fluorodeoxyglucose PET/CT in patients with primary bone tumors, osseous metastases, and multiple myeloma are reviewed. The clinical and research data supporting the utility of PET/CT in the evaluation of skeletal malignancies continues to grow.

Evolving role of FDG PET/CT in multiple myeloma imaging and management

OBJECTIVE

Multiple myeloma is the most common cause of primary malignancy in bones. Radiography has been the imaging reference standard for decades. However, the growing use of CT, MRI, and PET technology has led to earlier diagnosis of multiple myeloma, more accurate therapy assessment, and better prediction of patient outcome. This article is focused on the evolving role of (18)F-FDG PET/CT in multiple myeloma diagnosis, therapy assessment, and prognosis.

CONCLUSION

FDG PET/CT is a valuable imaging modality in diagnosis, therapy assessment, and prognosis of multiple myeloma.

Diagnosis and therapy of multiple myeloma

Many advances in the treatment of multiple myeloma have been made due to the use of transplantation and the introduction of novel agents including thalidomide, lenalidomide, and bortezomib. The first step is recognizing the symptoms and starting prompt treatment. Different strategies should be selected for young and elderly subjects. Young patients are commonly eligible for transplantation, which is now considered the standard approach for this setting, and various inductions therapies containing novel agents are available before transplantation. Elderly patients are usually not eligible for transplantation, and gentler approaches with new drugs combinations are used for their treatment.

Comparison of modern and conventional imaging techniques in establishing multiple myeloma-related bone disease: a systematic review

This systematic review of studies compared magnetic resonance imaging (MRI), (18) F-fluorodeoxyglucose positron emission tomography (FDG-PET), FDG-PET with computerized tomography (PET-CT) and CT with whole body X-Ray (WBXR) or (whole body) CT in order to provide evidence-based diagnostic guidelines in multiple myeloma bone disease. A comprehensive search of 3 bibliographic databases was performed; methodological quality was assessed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria (score 1-14). Data from 32 directly comparative studies were extracted. The mean QUADAS score was 7·1 (3-11), with quality hampered mainly by a poor description of selection and execution criteria. All index tests had a higher detection rate when compared to WBXR, with up to 80% more lesions detected by the newer imaging techniques; MRI (1·12-1·82) CT (1·04-1·33), PET (1·00-1·58) and PET-CT (1·27-1·45). However, the modern imaging techniques detected fewer lesions in the skull and ribs. In a direct comparison CT and MRI performed equally with respect to detection rate and sensitivity. This systematic review supports the International Myeloma Working Group guidelines, which recommend that WBCT can replace WBXR. In our opinion, the equal performance of MRI also indicates that it is a valuable alternative. As lesions of the skull and ribs are underdiagnosed by modern imaging techniques we advise additional X-rays of these regions. The consequences of this approach are discussed.

Clinical value of ¹¹C-methionine PET/CT in patients with plasma cell malignancy: comparison with ¹⁸F-FDG PET/CT

PURPOSE

PET/CT using FDG has been widely used for the imaging of various malignant tumours, including plasma cell malignancy (PCM), but (11)C-methionine (MET), as a radiolabelled amino acid tracer, may also be useful because PCM is able to activate protein synthesis. The purpose of this study was to evaluate the clinical value of PET/CT imaging using MET in PCM, including multiple myeloma, compared with that of FDG PET/CT.

METHODS

The study group comprised 20 patients with histologically proven PCM who underwent FDG PET/CT and MET PET/CT scans before (n = 6) or after (n = 14) treatment. Semiquantitative analysis was performed on a lesion basis. We also visually evaluated the scans qualitatively using a five-point scale (0, negative; 1, probably negative; 2, equivocal; 3, probably positive; 4, positive) on a lesion and a patient basis. The results were compared between the two scans.

RESULTS

Active PCM was confirmed in 15 patients, including two patients with extramedullary lesions. Uptake of MET tended to be higher (maximum standardized uptake value 10.3 ± 5.6, mean ± SD) than that of FDG (3.4 ± 2.7, p < 0.001), and more lesions of grade 3 or 4 were depicted by MET (MET 156 lesions vs. FDG 58 lesions). On a patient basis, two patients were accurately diagnosed only by MET. In the remaining 18 patients, consistent results were obtained, but potential upgrade of staging or restaging was necessary in 6 of 11 positive patients because more abnormal lesions were demonstrated by MET. The patient-based sensitivity, specificity and accuracy of MET for restaging were 89 %, 100 % and 93 %, respectively, while those of FDG were 78 %, 100 % and 86 %, respectively.

CONCLUSION

MET revealed an equal or greater number of lesions in PCM than FDG. MET may be especially useful when negative or inconclusive findings are obtained by FDG despite highly suspicious indications of recurrence.

Diagnosis and treatment of bone disease in multiple myeloma: spotlight on spinal involvement

Bone disease is observed in almost 80% of newly diagnosed symptomatic multiple myeloma patients, and spine is the bone site that is more frequently affected by myeloma-induced osteoporosis, osteolyses, or compression fractures. In almost 20% of the cases, spinal cord compression may occur; diagnosis and treatment must be carried out rapidly in order to avoid a permanent sensitive or motor defect. Although whole body skeletal X-ray is considered mandatory for multiple myeloma staging, magnetic resonance imaging is presently considered the most appropriate diagnostic technique for the evaluation of vertebral alterations, as it allows to detect not only the exact morphology of the lesions, but also the pattern of bone marrow infiltration by the disease. Multiple treatment modalities can be used to manage multiple myeloma-related vertebral lesions. Surgery or radiotherapy is mainly employed in case of spinal cord compression, impending fractures, or intractable pain. Percutaneous vertebroplasty or balloon kyphoplasty can reduce local pain in a significant fraction of treated patients, without interfering with subsequent therapeutic programs. Systemic antimyeloma therapy with conventional chemotherapy or, more appropriately, with combinations of conventional chemotherapy and compounds acting on both neoplastic plasma cells and bone marrow microenvironment must be soon initiated in order to reduce bone resorption and, possibly, promote bone formation. Bisphosphonates should also be used in combination with antimyeloma therapy as they reduce bone resorption and prolong patients survival. A multidisciplinary approach is thus needed in order to properly manage spinal involvement in multiple myeloma.

FDG-PET in the evaluation of myeloma in 2012

Multiple myeloma (MM) is a malignant haematological disease characterised by clonal proliferation of malignant plasma cells in the bone marrow. MM is expressed by diffuse infiltration of the bone marrow, focal bone lesions and extra-medullary lesions. Conventional staging follows the Salmon and Durie classification, which was recently revised (Salmon and Durie plus) to include MRI and FDG-PET examinations. FDG-PET is being evaluated for initial staging and therapeutic monitoring and its place still needs to be validated, particularly in comparison with MRI of the pelvis and spine, the reference examination for diagnosis, which is systematically combined with X-rays of the skeleton. Certain recent data in the literature suggest that FDG-PET provides better staging of the disease at the time of diagnosis than MRI, and that the examination has considerable prognostic value when it normalises after the initial courses of chemotherapy and at the end of treatment. As for the evaluation of lymphomas, the interpretation criteria should be standardised.

Metabolic tumor volume assessed by 18F-FDG PET/CT for the prediction of outcome in patients with multiple myeloma

(18)F-FDG PET/CT allows the direct measurement of metabolic tumor burden in a variety of different malignancies. The aim of this study was to assess whether metabolic tumor volume (MTV) determined by (18)F-FDG PET/CT could be used in the prediction of progression-free and overall survival in multiple myeloma patients.

METHODS

Forty-seven patients (18 women, 29 men; mean age ± SD, 63 ± 11 y) with stage IIIA disease who had undergone whole-body (18)F-FDG PET/CT were retrospectively evaluated. Images underwent a 3-dimensional region-of-interest analysis including all focal lesions with a maximum standardized uptake value > 2.5. The MTV of each lesion was calculated using an automated contouring program based on the standardized uptake value and developed with a threshold of 40% of the maximum standardized uptake value. The total MTV of each patient was defined as the sum of metabolic volume of all focal lesions. Patients were treated and then subjected to a mean follow-up period of 24 mo.

RESULTS

In the 47 patients studied, MTV range was 1.3-316.3 mL, with a median of 23.7 mL. A direct, significant correlation was found between MTV and the percentage of diffuse infiltration of bone marrow by plasma cells (r = 0.46, P = 0.006), whereas hemoglobin levels were inversely correlated with MTV (r = -0.56, P = 0.0001). At follow-up, patients who developed progressive disease (n = 18) showed a significantly higher MTV (74.7 ± 19.3 vs. 29.8 ± 5.1 mL, P = 0.009) than patients without progressive disease (n = 29). Furthermore, patients who died of myeloma (n = 9) had a significantly higher MTV (123.2 ± 30.6 vs. 28.9 ± 4.2 mL, P = 0.0001) than survivors (n = 38). No differences in age, plasma cell infiltration, M protein, albumin, β2-microglobulin, performance status, International Staging System score, and presence or absence of a bone marrow transplant were found between groups. The MTV cutoff level was determined by receiver-operating-characteristic curve analysis, and the best discriminative value found for predicting progression-free and overall survival was 42.2 and 77.6 mL, respectively. By Kaplan-Meier analysis and log-rank testing, progression-free and overall survival at follow-up were significantly better in patients showing an MTV lower than the cutoff than in those having an MTV higher than the cutoff (χ(2) = 3.9, P = 0.04, and χ(2) = 56.3, P < 0.0001, respectively).

CONCLUSION

The direct measurement of tumor burden obtained by calculating MTV on (18)F-FDG PET/CT images may be used in the prediction of progression-free and overall survival in myeloma patients.