Comparison of imaging with FDG PET/CT with other imaging modalities in myeloma

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

Background

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

Methods

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

Results

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

Conclusion

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

Whole body imaging in musculoskeletal oncology: when, why, and how

The use of whole-body imaging has become increasingly popular in oncology due to the possibility of evaluating total tumor burden with a single imaging study. This is particularly helpful in cases of widespread disease where dedicated regional imaging would make the evaluation more expensive, time consuming, and prone to more risks. Different techniques can be used, including whole-body MRI, whole-body CT, and PET-CT. Common indications include surveillance of cancer predisposing syndromes, evaluation of osseous metastases and clonal plasma cell disorders such as multiple myeloma, and evaluation of soft tissue lesions, including peripheral nerve sheath tumors. This review focuses on advanced whole-body imaging techniques and their main uses in musculoskeletal oncology.

Comparison of [68Ga]-FAPI PET/CT and [18F]-FDG PET/CT in Multiple Myeloma: Clinical Experience

Objective: In this study, we aimed to compare [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging to detect lesions in multiple myeloma. Methods: A total of 14 patients with multiple myeloma who underwent [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging were included in this retrospective study. SUVmax values of [68Ga]FAPI and [18F]FDG were compared according to lesion locations. Also, lesion localization ability of both imaging methods was compared on the patient basis. Results: In 4 of 14 patients, [68Ga]FAPI PET/CT and [18F]FDG PET/CT have not detected any bone lesions. In 8 of the remaining 10 patients [18F]FDG PET/CT detected bone lesions but in this group, 6 patients showed more higher SUVmax values than [18F]FDG PET/CT in [68Ga]FAPI PET/CT.In contrast, 2 of 8 patients showed more higher SUVmax values than [68Ga]FAPI PET/CT in [18F]FDG PET/CT. Moreover, [68Ga]FAPI PET/CT detected bone lesions in two patients, which werenot detected by [18F]FDG PET/CT. Also, in five patients, [68Ga]FAPI PET/CT showed more bone lesions in comparison with[18F]FDG PET/CT. Only one patient, [18F]FDG PET/CT showed more bone lesions. Three extramedullary involvements were observed in the following locations: lung, presacral lymph node, and soft tissue mass lateral to the right maxillary sinus. Among these involvements, higher SUVmax values were observed in the lung and presacral lymph node with [68Ga]FAPI compared to [18F]FDG. However, the soft tissue mass showed a higher SUVmax value in [18F]FDG than [68Ga]FAPI. Conclusions: No significant superiority was observed in [68Ga]FAPI PET/CT over [18F]FDG PET/CT in patients with MM. However, [68Ga]FAPI PET/CT can be utilized as a complementary imaging method to [18F]FDG PET/CT in some settings, especially in low-[18F]FDG affinity and inconclusive cases. Considering the favorable aspects of [68Ga]FAPI PET/CT in MM, such as low background activity, absence of non-specific bone marrow, and physiological brain involvement, further studies with a larger sample size should be conducted.

Role of FDG PET in the staging of multiple myeloma

¹⁸F-Fluorodeoxyglucose (FDG) PET has been used for staging of hematologic malignancies for years. In multiple myeloma, this imaging modality can be used in many different scenarios, including initial staging, evaluation of treatment response, and investigation of residual disease or early relapse. FDG PET-CT has excellent diagnostic performance, similar to other advanced imaging modalities such as whole-body CT and MRI, and it is particularly helpful for the assessment of extramedullary disease. It also offers important prognostic information on survival and risk of relapse, both at baseline and after therapy. This review will cover the main applications, advantages, and limitations of FDG PET-CT in multiple myeloma and related clonal plasma cell proliferative disorders, such as smoldering multiple myeloma and plasmacytoma.

Metabolic Volume Measurements in Multiple Myeloma

Multiple myeloma (MM) accounts for 10-15% of all hematologic malignancies, as well as 20% of deaths related to hematologic malignant tumors, predominantly affecting bone and bone marrow. Positron emission tomography/computed tomography with 18F-fluorodeoxyglucose (FDG-PET/CT) is an important method to assess the tumor burden of these patients. It is often challenging to classify the extent of disease involvement in the PET scans for many of these patients because both focal and diffuse bone lesions may coexist, with varying degrees of FDG uptake. Different metrics involving volumetric parameters and texture features have been proposed to objectively assess these images. Here, we review some metabolic parameters that can be extracted from FDG-PET/CT images of MM patients, including technical aspects and predicting MM outcome impact. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are volumetric parameters known to be independent predictors of MM outcome. However, they have not been adopted in clinical practice due to the lack of measuring standards. CT-based segmentation allows automated, and therefore reproducible, calculation of bone metabolic metrics in patients with MM, such as maximum, mean and standard deviation of the standardized uptake values (SUV) for the entire skeleton. Intensity of bone involvement (IBI) is a new parameter that also takes advantage of this approach with promising results. Other indirect parameters obtained from FDG-PET/CT images, such as visceral adipose tissue glucose uptake and subcutaneous adipose tissue radiodensity, may also be useful to evaluate the prognosis of MM patients. Furthermore, the use and quantification of new radiotracers can address different metabolic aspects of MM and may have important prognostic implications.

Optimization of whole-body 2-[18F]FDG-PET/MRI imaging protocol for the initial staging of patients with myeloma

OBJECTIVE

To determine the optimal 2-[¹⁸F]FDG-PET/MRI imaging protocol for the initial staging of patients with suspected or confirmed multiple myeloma.

METHODS

Radiologists and nuclear medicine specialists reviewed all PET/MRI exams of 104 patients with a monoclonal gammopathy (MG). The presence of focal and diffuse bone marrow involvement (BMI) was assessed using 4 different image datasets: WB-MRI, PET, WB-PET/MRI, and WB-DCE-PET/MRI. A reference standard was established by a panel review of all baseline and follow-up imaging, and biological and pathological information. The diagnostic performance for each image dataset to detect BMI was evaluated and compared (Fisher's exact test).

RESULTS

Sensitivity, specificity, and accuracy for focal BMI of WB-MRI was 87%, 97%, and 92%; of PET was 78%, 97%, and 95%; of WB-PET/MRI was 93%, 97%, and 95%; and of WB-DCE-PET/MRI was 93%, 97%, and 95%, respectively. WB-PET/MRI and WB-DCE-PET/MRI were statistically superior to PET (p = 0.036) without decreasing specificity. The sensitivity, specificity, and accuracy of WB-MRI for diffuse BMI detection was 91%, 80%, and 85%; of 3DT1-PET was 53%, 89%, and 74%; of WB-PET/MRI was 98%, 66%, and 79%; and of WB-DCE-PET/MRI was 98%, 59%, and 75%, respectively. PET lacked sensitivity compared to all other dataset studies (p < 0.0001). WB-MRI had the best accuracy without reaching statistical significance when compared to the other datasets.

CONCLUSION

The WB-PET/MRI dataset including T1 and T2 Dixon, WB-DWI, and PET images provides optimal diagnostic performance to detect both focal lesions and diffuse BMI, with limited added value of WB-DCE for baseline staging of patients with MG. Key Points • The combination of morphological and functional MRI sequences and metabolic (2-[¹⁸F]FDG-PET) images increases the diagnostic performance of PET/MRI to detect focal bone lesions. • The adjunction of dynamic contrast-enhanced sequences did not improve diagnostic performance.

Skeletal Survey in Multiple Myeloma: Role of Imaging

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

Comparison of the diagnostic performance and impact on management of 18F-FDG PET/CT and whole-body MRI in multiple myeloma

PURPOSE

Comparative data on the impact of imaging on management is lacking for multiple myeloma. This study compared the diagnostic performance and impact on management of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and whole-body magnetic resonance imaging (WBMRI) in treatment-naive myeloma.

METHODS

Forty-six patients undergoing 18F-FDG PET/CT and WBMRI were reviewed by a nuclear medicine physician and radiologist, respectively, for the presence of myeloma bone disease. Blinded clinical and imaging data were reviewed by two haematologists in consensus and management recorded following clinical data ± 18F-FDG PET/CT or WBMRI. Bone disease was defined using International Myeloma Working Group (IMWG) criteria and a clinical reference standard. Per-patient sensitivity for lesion detection was established. McNemar test compared management based on clinical assessment ± 18F-FDG PET/CT or WBMRI.

RESULTS

Sensitivity for bone lesions was 69.6% (32/46) for 18F-FDG PET/CT (54.3% (25/46) for PET component alone) and 91.3% (42/46) for WBMRI. 27/46 (58.7%) of cases were concordant. In 19/46 patients (41.3%) WBMRI detected more focal bone lesions than 18F-FDG PET/CT. Based on clinical data alone, 32/46 (69.6%) patients would have been treated. Addition of 18F-FDG PET/CT to clinical data increased this to 40/46 (87.0%) patients (p = 0.02); and WBMRI to clinical data to 43/46 (93.5%) patients (p = 0.002). The difference in treatment decisions was not statistically significant between 18F-FDG PET/CT and WBMRI (p = 0.08).

CONCLUSION

Compared to 18F-FDG PET/CT, WBMRI had a higher per patient sensitivity for bone disease. However, treatment decisions were not statistically different and either modality would be appropriate in initial staging, depending on local availability and expertise.

Role of imaging in multiple myeloma

With rapid advancements in the diagnosis and treatment of multiple myeloma (MM), imaging has become instrumental in detection of intramedullary and extramedullary disease, providing prognostic information, and assessing therapeutic efficacy. Whole-body low dose computed tomography (WBLDCT) has emerged as the study of choice to detect osteolytic bone disease. Positron emission tomography/computed tomography (PET/CT) combines functional and morphologic information to identify MM disease activity and assess treatment response. Magnetic resonance imaging (MRI) has excellent soft-tissue contrast and is the modality of choice for bone marrow evaluation. This review focuses on the imaging modalities available for MM patient management, highlighting advantages, disadvantages, and applications of each.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

KEY POINTS

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

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

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

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

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

National survey of imaging practice for suspected or confirmed plasma cell malignancies

OBJECTIVE:

Cross-sectional imaging is now recommended by the National Institute for Health and Care Excellence (NICE) for patients with suspected and newly diagnosed myeloma instead of skeletal survey. The objectives of this study were: (1) To evaluate compliance of current UK imaging practice with reference to National Institute for Health and Care Excellence best-practice clinical guidelines for plasma cell malignancies. (2) To identify factors which may influence diagnostic imaging choices.

METHODS:

We conducted a national online survey to assess compliance with guidelines and to identify challenges to implementation (endorsed by Myeloma UK, UK Myeloma Forum and the British Society of Skeletal Radiologists).

RESULTS:

Responses were received from 31 district general and 28 teaching hospitals. For suspected and confirmed myeloma, skeletal survey remained the most frequent first-line imaging test (suspected myeloma 44.3%, confirmed myeloma 37.7%). Only 9.8 % of responders offered first-line whole body MRI.

CONCLUSION:

Significant challenges remain to standardisation of imaging practice in accordance with national best-practice guidelines.

ADVANCES IN KNOWLEDGE:

This is the first publication to date evaluating current UK imaging practice for assessing myeloma since the publication of new guidelines recommending use of advanced cross-sectional imaging techniques. Skeletal survey remains the most commonly performed first-line imaging test in patients with suspected or confirmed myeloma and this is largely due to resource limitations within radiology departments.

Management of Primary Osseous Spinal Tumors with PET

Knowledge of the PET imaging findings of osseous spinal neoplasms is essential, because they are common incidental findings on PET scans done for staging of unrelated primary malignancies. Additionally, PET can help differentiate lesions that are not clearly defined by anatomic modalities alone. PET can also be used for follow-up of aggressive tumors to assess response to treatment, often proving superior to CT or MR imaging alone for this purpose. This review discusses the role of PET/CT and PET/MR imaging in the diagnosis and management of primary benign and malignant osseous tumors of the spine.

Applications of PET/CT and PET/MR Imaging in Primary Bone Malignancies

Primary bone malignancies are characterized with anatomic imaging. However, in recent years, there has been an increased interest in PET/computed tomography scanning and PET/MRI with fludeoxyglucose F 18 for evaluating and staging musculoskeletal neoplasms. These hybrid imaging modalities have shown promise largely owing to their high sensitivity, ability to perform more thorough staging, and ability to monitor treatment response. This article reviews the current role of PET/computed tomography scanning and PET/MRI in primary malignancies of bone, with an emphasis on imaging characteristics, clinical usefulness, and current limitations.

Diagnostic performance of 18F-FDG PET/CT and whole-body MRI before and early after treatment of multiple myeloma: a prospective comparative study

OBJECTIVE

To determine the diagnostic accuracy of WB-MRI and ¹⁸F-FDG PET/CT in detecting infiltration pattern, disease activity, and response to treatment in patients with multiple myeloma (MM).

MATERIALS AND METHODS

Fifty-six patients with confirmed MM were included in the present study for pre-treatment evaluation. Among these individuals, 22 patients were available for the post-treatment evaluation of response to therapy. All patients were imaged with both WB-MRI and ¹⁸F-FDG PET/CT. All radiographic findings of infiltration pattern, disease activity, and response to therapy were compared. The diagnostic performance of both modalities was estimated using bone marrow aspirate and biopsy as the reference test.

RESULTS

For detection of active myelomatous tissue at diagnosis, WB-MRI achieved higher sensitivity (94%) than ¹⁸F-FDG PET/CT (75%) (p = 0.0039), whereas both modalities achieved the same specificity (80%). For detection of residual myelomatous tissue after treatment, ¹⁸F-FDG PET/CT achieved higher specificity (86%) than WB-MRI (43%) (p = 0.0081), whereas both modalities achieved the same sensitivity (75%).

CONCLUSION

WB-MRI is more sensitive than ¹⁸F-FDG PET/CT in the diagnosis of MM before treatment; however, ¹⁸F-FDG PET/CT is more specific than WB-MRI in detecting residual involvement in treated patients.

Comparison of whole body magnetic resonance imaging (WBMRI) to whole body computed tomography (WBCT) or 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) in patients with myeloma: Systematic review of diagnostic performance

OBJECTIVES

To undertake a systematic review to determine the diagnostic performance of whole body MRI (WBMRI) including diffusion weighted sequences (DWI) compared to whole body computed tomography (WBCT) or 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) in patients with myeloma.

METHODS

Two researchers searched the primary literature independently for WBMRI studies of myeloma. Data were extracted focusing on the diagnostic ability of WBMRI versus WBCT and 18F-FDG PET/CT. Meta-analysis was intended.

RESULTS

6 of 2857 articles were eligible that included 147 patients, published from 2008 to 2016. Studies were heterogeneous including both newly diagnosed & relapsed patients. All were single centre studies. Four of the six studies (66.7%) accrued prospectively and 5/6 (83.3%, 3 prospective) included WBMRI and 18F-FDG PET/CT. Three of seven (42.9%) included DWI. The lack of an independent reference standard for individual lesions was noted in 5/6 (83.3%) studies. Studies reported that WBMRI detected more lesions than 18F-FDG PET/CT (sensitivity 68-100% versus 47-100%) but was less specific (specificity 37-83% versus 62-85.7%). No paper assessed impact on management.

CONCLUSIONS

Studies were heterogeneous, the majority lacking an independent reference standard. Future prospective trials should address these limitations and assess the impact of WBMRI on management.

Solitary Osteogenic Sternum Plasmacytoma on Bone Scintigraphy and FDG PET/CT

We reported a rare solitary osteogenic sternum plasmacytoma case. A 49-year-old woman experienced progressing pain in the sternum for 2 years. Abnormal Tc-MDP accumulation and increase in F-FDG uptake (SUVmax, 4.4) were co-localized with the osteogenic lesion in the sternum body detected by diagnostic CT. The lesion was histologically confirmed as plasma cell neoplasm suggestive of plasmacytoma. The patient had good response to radiotherapy.

Guidelines for the use of imaging in the management of patients with myeloma

The role of imaging in myeloma has gained increasing importance over the past few years. The recently revised definition of myeloma from the International Myeloma Working Group (IMWG) includes cross sectional imaging as a method to define bone disease and also incorporates its use in the disease definition for patients with suspected smouldering myeloma. The National Institute for Health and Care Excellence myeloma guidelines also recommend cross sectional imaging for patients with suspected myeloma. There is also increasing use of imaging in disease assessments and the International Myeloma Working Group has recently incorporated imaging in defining new response categories of minimal residual disease negativity, with or without imaging-based evidence of disease. Plain X-rays have previously been the standard imaging modality included in a myeloma work up at presentation but evidence is mounting for use of cross-sectional modalities such as computed tomography (CT), magnetic resonance imaging (MRI) and 18 fluoro-deoxyglucose (18 F-FDG) positron emission tomography (PET)/CT. Funding and therefore availability of newer imaging techniques remains a barrier. Here, we propose an evidence-based approach to the use and technical application of the latest imaging modalities at diagnosis and in the follow-up of patients with myeloma and plasmacytoma.

Prospective Evaluation of Magnetic Resonance Imaging and [18F]Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography at Diagnosis and Before Maintenance Therapy in Symptomatic Patients With Multiple Myeloma Included in the IFM/DFCI 2009 Trial: Results of the IMAJEM Study

Purpose Magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) are important imaging techniques in multiple myeloma (MM). We conducted a prospective trial in patients with MM aimed at comparing MRI and PET-CT with respect to the detection of bone lesions at diagnosis and the prognostic value of the techniques. Patients and Methods One hundred thirty-four patients received a combination of lenalidomide, bortezomib, and dexamethasone (RVD) with or without autologous stem-cell transplantation, followed by lenalidomide maintenance. PET-CT and MRI were performed at diagnosis, after three cycles of RVD, and before maintenance therapy. The primary end point was the detection of bone lesions at diagnosis by MRI versus PET-CT. Secondary end points included the prognostic impact of MRI and PET-CT regarding progression-free (PFS) and overall survival (OS). Results At diagnosis, MRI results were positive in 127 of 134 patients (95%), and PET-CT results were positive in 122 of 134 patients (91%; P = .33). Normalization of MRI after three cycles of RVD and before maintenance was not predictive of PFS or OS. PET-CT became normal after three cycles of RVD in 32% of the patients with a positive evaluation at baseline, and PFS was improved in this group (30-month PFS, 78.7% v 56.8%, respectively). PET-CT normalization before maintenance was described in 62% of the patients who were positive at baseline. This was associated with better PFS and OS. Extramedullary disease at diagnosis was an independent prognostic factor for PFS and OS, whereas PET-CT normalization before maintenance was an independent prognostic factor for PFS. Conclusion There is no difference in the detection of bone lesions at diagnosis when comparing PET-CT and MRI. PET-CT is a powerful tool to evaluate the prognosis of de novo myeloma.

Role of 18F-FDG PET/CT in the diagnosis and management of multiple myeloma and other plasma cell disorders: a consensus statement by the International Myeloma Working Group

The International Myeloma Working Group consensus aimed to provide recommendations for the optimal use of ¹⁸fluorodeoxyglucose (¹⁸F-FDG) PET/CT in patients with multiple myeloma and other plasma cell disorders, including smouldering multiple myeloma and solitary plasmacytoma. ¹⁸F-FDG PET/CT can be considered a valuable tool for the work-up of patients with both newly diagnosed and relapsed or refractory multiple myeloma because it assesses bone damage with relatively high sensitivity and specificity, and detects extramedullary sites of proliferating clonal plasma cells while providing important prognostic information. The use of ¹⁸F-FDG PET/CT is mandatory to confirm a suspected diagnosis of solitary plasmacytoma, provided that whole-body MRI is unable to be performed, and to distinguish between smouldering and active multiple myeloma, if whole-body X-ray (WBXR) is negative and whole-body MRI is unavailable. Based on the ability of ¹⁸F-FDG PET/CT to distinguish between metabolically active and inactive disease, this technique is now the preferred functional imaging modality to evaluate and to monitor the effect of therapy on myeloma-cell metabolism. Changes in FDG avidity can provide an earlier evaluation of response to therapy compared to MRI scans, and can predict outcomes, particularly for patients who are eligible to receive autologous stem-cell transplantation. ¹⁸F-FDG PET/CT can be coupled with sensitive bone marrow-based techniques to detect minimal residual disease (MRD) inside and outside the bone marrow, helping to identify those patients who are defined as having imaging MRD negativity.

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.

FDG-PET imaging in hematological malignancies

The majority of aggressive lymphomas is characterized by an up regulated glycolytic activity, which enables the visualization by F-18 FDG-PET/CT. One-stop hybrid FDG-PET/CT combines the functional and morphologic information, outperforming both, CT and FDG-PET as separate imaging modalities. This has resulted in several recommendations using FDG-PET/CT for staging, restaging, monitoring during therapy, and assessment of treatment response as well as identification of malignant transformation. FDG-PET/CT may obviate the need for a bone marrow biopsy in patients with Hodgkin's lymphoma and diffuse large B cell lymphoma. FDG-PET/CT response assessment is recommended for FDG-avid lymphomas, whereas CT-based response evaluation remains important in lymphomas with low or variable FDG avidity. The treatment induced change in metabolic activity allows for assessment of response after completion of therapy as well as prediction of outcome early during therapy. The five-point scale Deauville Criteria allows the assessment of treatment response based on visual FDG-PET analysis. Although the use of FDG-PET/CT for prediction of therapeutic response is promising it should only be conducted in the context of clinical trials. Surveillance FDG-PET/CT after complete remission is discouraged due to the relative high number of false-positive findings, which in turn may result in further unnecessary investigations. Future directions include the use of new PET tracers such as F-18 fluorothymidine (FLT), a surrogate biomarker of cellular proliferation and Ga-68 CXCR4, a chemokine receptor imaging biomarker as well as innovative digital PET/CT and PET/MRI techniques.

MR imaging and PET/CT in diagnosis and management of multiple myeloma

Multiple myeloma is a common hematologic malignancy among the elderly population. Although there have been many advances in treatment over the past few decades, the overall prognosis for the disease remains poor. Conventional radiography has long been the standard of reference for the imaging of multiple myeloma. However, 10%-20% of patients with multiple myeloma do not have evidence of disease at conventional radiography. There is a growing body of evidence supporting use of magnetic resonance (MR) imaging and 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in diagnosis and management of multiple myeloma. MR imaging is useful in detection of bone marrow infiltration, a finding often missed at conventional radiography. FDG PET/CT is especially sensitive for the detection of extramedullary disease and can help detect the metabolically active lesions that often precede evidence of osseous destruction at conventional radiography. MR imaging and FDG PET/CT are useful tools that can provide essential information for diagnosis and management of patients with multiple myeloma. Both modalities allow accurate localization of disease after chemotherapy or autologous stem cell transplantation and can provide important prognostic information that can influence further clinical decision making regarding therapy, particularly when tumor serum markers may be a less reliable indicator of disease burden after repeated treatments.

Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) magnetic resonance imaging as a biomarker for symptomatic multiple myeloma

Introduction

To evaluate the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) magnetic resonance imaging (MRI) to discriminate between symptomatic and asymptomatic myeloma in lumbar bone marrow without visible focal lesions.

Materials and Methods

The lumbar spine was examined with 3-T MRI in 11 patients with asymptomatic myeloma and 24 patients with symptomatic myeloma. The fat-signal fraction was calculated from the ratio of the signal intensity in the fat image divided by the signal intensity of the corresponding ROI in the in-phase IDEAL image. The t test was used to compare the asymptomatic and symptomatic groups. ROC curves were constructed to determine the ability of variables to discriminate between symptomatic and asymptomatic myeloma.

Results

Univariate analysis showed that β2-microglobulin and bone marrow plasma cell percent (BMPC%) were significantly higher and fat-signal fraction was significantly lower with symptomatic myeloma than with asymptomatic myeloma. Areas under the curve were 0.847 for β₂;-microglobulin, 0.834 for fat-signal fraction, and 0.759 for BMPC%.

Conclusion

The fat-signal fraction as a biomarker for multiple myeloma enables discrimination of symptomatic myeloma from asymptomatic myeloma. The fat-signal fraction offers superior sensitivity and specificity to BMPC% of biopsy specimens.

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.

State of the art imaging of multiple myeloma: comparative review of FDG PET/CT imaging in various clinical settings

18-Flurodeoxyglucose Positron Emission Tomography with computed tomography (FDG PET/CT) and Magnetic Resonance Imaging (MRI) have higher sensitivity and specificity than whole-body X-ray (WBXR) survey in evaluating disease extent in patients with multiple myeloma (MM). Both modalities are now recommended by the Durie-Salmon Plus classification although the emphasis is more on MRI than PET/CT. The presence of extra-medullary disease (EMD) as evaluated by PET/CT imaging, initial SUVmax and number of focal lesions (FL) are deemed to be strong prognostic parameters at staging. MRI remains the most sensitive technique for the detection of diffuse bone marrow involvement in both the pre and post-therapy setting. Compression fractures are best characterized with MRI signal changes, for determining vertebroplasty candidates. While PET/CT allows for earlier and more specific evaluation of therapeutic efficacy compared to MRI, when signal abnormalities persist years after treatment. PET/CT interpretation, however, can be challenging in the vertebral column and pelvis as well as in cases with post-therapy changes. Hence, a reading approach combining the high sensitivity of MRI and superior specificity of FDG PET/CT would be preferred to increase the diagnostic accuracy. In summary, the established management methods in MM, mainly relying on biological tumor parameters should be complemented with functional imaging data, both at staging and restaging for optimal management of MM.

Imaging of multiple myeloma: usefulness of MRI and PET/CT

Multiple myeloma is a heterogeneous hematologic disorder of plasma cells with varied bone marrow imaging appearances. With advancements in both treatment and use of advanced imaging over the last several decades, it is important for radiologists to recognize the imaging presentation of the disease and the staging implications of imaging. This paper reviews the staging as it relates to imaging, consensus recommendations for imaging, expected imaging appearances of myeloma, pitfalls, and complications associated with treatment that are demonstrable on imaging.

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.

Imaging of myeloma: beyond lytic lesions

SUMMARY This review will focus on the imaging findings present in patients with typical symptomatic multiple myeloma. The emphasis will be on recent developments related to advanced imaging techniques. There are several different ways to stage or risk-stratify patients with symptomatic multiple myeloma after the diagnosis has been established. The International Myeloma Working Group issued a consensus statement regarding imaging of myeloma patients in 2009. The consensus was that the conventional radiographic survey should still be carried out as the baseline imaging study and that MRI should be added whenever possible. Many other imaging exams are available including: CT, PET/CT, MRI and sestamibi. The strengths and weaknesses of all of the available imaging techniques will be summarized.

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.

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 challenges of an oligosecretory plasma cell dyscrasia

Light chain deposition disease (LCDD) and immunoglobulin light chain (AL) amyloidosis are uncommon, and heterogeneous clonal plasma cell (PC) proliferative disorders defined by the different biochemical characteristics of the underlying anomalous immunoglobulin. The deposits are usually multisystemic and the two diseases can coexist. The diagnosis is sometimes made difficult by the absence of a detectable paraprotein by routine immunofixation techniques, and the use of serum-free light chain (FLC) immunoassay brought new value in terms of their diagnosis, prognosis and assessment of treatment response. Association of LCDD and AL amyloidosis with multiple myeloma (MM) at the time of diagnosis is common, but further progression to this condition is considered rare. We present a case of a patient diagnosed with systemic LCDD and AL amyloidosis of atypical biochemical characteristics, with no paraprotein detected in immunoelectrophoresis and immunofixation techniques, who progressed to MM in the later course of her disease.

Multiple myeloma lesion detection with whole body CT versus radiographic skeletal survey

OBJECTIVE

To compare accuracy of CT versus radiographs in detecting myeloma lesions.

MATERIALS AND METHODS

Retrospective review of patients who were simultaneously evaluated with radiographs and PET/CT scans. Two radiologists independently assessed each modality.

RESULTS

Total number of lesions detected with CT was 968 versus 248 for radiographs (p < .001). Nine patients (18%) had no lesions on either CT or radiographs. Of the remaining 42 patients, 39 had more lesions on CT. CT could have resulted in upstaging of disease in 31 cases (61%).

CONCLUSION

CT is superior for detecting myeloma lesions.

Very late antigen-4 (α(4)β(1) Integrin) targeted PET imaging of multiple myeloma

Biomedical imaging techniques such as skeletal survey and (18)F-fluorodeoxyglucose (FDG)/Positron Emission Tomography (PET) are frequently used to diagnose and stage multiple myeloma (MM) patients. However, skeletal survey has limited sensitivity as it can detect osteolytic lesions only after 30-50% cortical bone destruction, and FDG is a marker of cell metabolism that has limited sensitivity for intramedullary lesions in MM. Targeted, and non-invasive novel probes are needed to sensitively and selectively image the unique molecular signatures and cellular processes associated with MM. Very late antigen-4 (VLA-4; also called α(4)β(1) integrin) is over-expressed on MM cells, and is one of the key mediators of myeloma cell adhesion to the bone marrow (BM) that promotes MM cell trafficking and drug resistance. Here we describe a proof-of-principle, novel molecular imaging strategy for MM tumors using a VLA-4 targeted PET radiopharmaceutical, (64)Cu-CB-TE1A1P-LLP2A. Cell uptake studies in a VLA-4-positive murine MM cell line, 5TGM1, demonstrated receptor specific uptake (P<0.0001, block vs. non-block). Tissue biodistribution at 2 h of (64)Cu-CB-TE1A1P-LLP2A in 5TGM1 tumor bearing syngeneic KaLwRij mice demonstrated high radiotracer uptake in the tumor (12±4.5%ID/g), and in the VLA-4 rich organs, spleen (8.8±1.0%ID/g) and marrow (11.6±2.0%ID/g). Small animal PET/CT imaging with (64)Cu-CB-TE1A1P-LLP2A demonstrated high uptake in the 5TGM1 tumors (SUV 6.6±1.1). There was a 3-fold reduction in the in vivo tumor uptake in the presence of blocking agent (2.3±0.4). Additionally, (64)Cu-CB-TE1A1P-LLP2A demonstrated high binding to the human MM cell line RPMI-8226 that was significantly reduced in the presence of the cold targeting agent. These results provide pre-clinical evidence that VLA-4-targeted imaging using (64)Cu-CB-TE1A1P-LLP2A is a novel approach to imaging MM tumors.

Diagnostic imaging for spinal disorders in the elderly: a narrative review

The high prevalence of neck and low back pain in the rapidly aging population is associated with significant increases in health care expenditure. While spinal imaging can be useful to identify less common causes of neck and back pain, overuse and misuse of imaging services has been widely reported. This narrative review aims to provide primary care providers with an overview of available imaging studies with associated potential benefits, adverse effects, and costs for the evaluation of neck and back pain disorders in the elderly population. While the prevalence of arthritis and degenerative disc disease increase with age, fracture, infection, and tumor remain uncommon. Prevalence of other conditions such as spinal stenosis and abdominal aortic aneurysm (AAA) also increase with age and demand special considerations. Radiography of the lumbar spine is not recommended for the early management of non-specific low back pain in adults under the age of 65. Aside from conventional radiography for suspected fracture or arthritis, magnetic resonance imaging (MRI) and computed tomography (CT) offer better characterization of most musculoskeletal diseases. If available, MRI is usually preferred over CT because it involves less radiation exposure and has better soft-tissue visualization. Use of subspecialty radiologists to interpret diagnostic imaging studies is recommended.

Hematopoietic tumors and metastases involving bone

This review explores in depth the most common malignant process involving the bone, namely metastatic disease, as well as some of the more common proliferative forms of hematopoietic disease of bone marrow. These are commonly encountered pathologic processes that often have vague nonspecific symptoms. Imaging findings are frequently subtle on initial radiographs; however, advanced imaging techniques, including CT, MR, and positron emission tomography, allow for accurate diagnosis, staging, and follow-up in most cases.

18F-FDG PET/CT for detection and localization of residual or recurrent disease in patients with multiple myeloma after stem cell transplantation

PURPOSE

The aim of the study was to determine the diagnostic performance of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT for the detection and localization of residual or recurrent disease in patients with multiple myeloma (MM) after stem cell transplantation.

METHODS

A total of 197 whole-body (18)F-FDG PET/CT scans were performed in 99 patients with MM at different time points in the course of disease after autologous or allogeneic stem cell transplantation. Post-transplant PET/CT scans and clinical remission status as determined by the clinical gold standard (Uniform Response Criteria) were analysed and compared.

RESULTS

A total of 576 focal osseous and extramedullary lesions were detected in 79 scans. Additional diffuse bone marrow involvement was detected in 17 patients. (18)F-FDG PET/CT had a sensitivity of 54.6%, a specificity of 82.1%, a positive predictive value of 82.3%, a negative predictive value of 54.2% and an overall accuracy of 65.5%. The sensitivity of (18)F-FDG PET/CT was shown to depend on the disease category according to the Uniform Response Criteria for myeloma.

CONCLUSION

In patients with MM in the post-transplant setting, (18)F-FDG PET/CT may (1) contribute to the detection and localization of disease, (2) provide information about the extent of distinct myeloma manifestations and the total disease burden and (3) add information about the metabolic activity of disease, but (4) has substantially lower sensitivity for this purpose compared to the pretreatment setting.

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.

The value of FDG PET/CT in the initial staging and bone marrow involvement of patients with multiple myeloma

OBJECTIVE

The aim of this study was to describe the role of positron emission tomography/computed tomography (PET/CT) with fluorine-18 fluorodeoxyglucose (FDG) in the detection of skeletal and visceral involvement in patients with MM (multiple myeloma) at the initial diagnosis and to evaluate the relation between maximum standardized uptake values (SUVmax) of FDG with bone marrow cellularity and plasma cell ratios.

MATERIALS AND METHODS

The study population consisted of 42 patients (15 F, 28 M; mean ± SD age; 47 ± 12 years). Thirty-two patients were referred for initial diagnosis and ten patients were referred for assessment of therapy response. PET/CT scan was obtained 60 min after the administration of 5.4 MBq/kg FDG. The SUVmax of FDG uptake was measured from the region of interest, which was placed at the site of most prominent lesion in bone marrow in PET/CT images.

RESULTS

Thirty patients were positive (29 of 32 initially diagnosed, one of ten previously treated) and 12 patients were negative on PET/CT scan. Conventional radiological methods were negative in three of 30 FDG PET/CT-positive patients and these methods did not show any pathological finding in 12 FDG PET/CT-negative patients. The sensitivity of FDG PET in detecting bone marrow involvement at initial diagnosis was 90%. There was a significant correlation between SUVmax values and bone marrow biopsy cellularity and plasma cell ratios, (r = 0.54 and r = 0.74, p < 0.01).

CONCLUSIONS

The results of this study demonstrated that FDG-PET is a useful technique for the assessment of MM and the correlation between SUVmax and plasma cell ratios in bone marrow biopsy may avoid repeated bone marrow biopsies in the follow-up period.