Whole-body low-dose multidetector row-CT in the diagnosis of multiple myeloma: an alternative to conventional radiography

Current concepts in the evaluation of multiple myeloma with MR imaging and FDG PET/CT

Multiple myeloma is a heterogeneous group of plasma cell neoplasms that primarily involve bone marrow but also may occur in the soft tissue. Although the disease varies in its manifestations and its course, it is eventually fatal in all cases. Over the past 2 decades, significant advances have been made in our understanding of the genetics and pathogenesis of multiple myeloma and in its treatment. The use of magnetic resonance (MR) imaging and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT) has improved sensitivity for the detection of this disease. PET aids in the identification of active multiple myeloma on the basis of FDG uptake, and MR imaging helps identify multiple myeloma from its infiltration of normal fat within the bone marrow, which occurs in characteristic patterns that correlate with the disease stage. The increased sensitivity of these advanced cross-sectional imaging techniques has led to further refinement of the classic Durie and Salmon staging system. In addition, these imaging techniques allow a more reliable assessment of the disease response to treatment with current regimens, which may include autologous stem cell transplantation as well as various medications. In lesions that respond to chemotherapeutic agents, the replacement of previously infiltrated marrow by fat is seen at MR imaging and decreased FDG uptake is seen at FDG PET; however, a lengthy and intensive regimen may be necessary before the MR imaging appearance of marrow normalizes. Lytic lesions seen at CT almost always persist even after successful treatment. To provide an accurate assessment, radiologists must be familiar not only with the appearances of multiple myeloma and its mimics but also with common treatment-related findings.

Image quality in low-dose multidetector computed tomography: a pilot study to assess feasibility and dose optimization in whole-body bone imaging

OBJECTIVE

To study the impact of dose parameters on image quality at whole-body low-dose multidetector computed tomography (CT) in an attempt to derive parameters that allow diagnostic quality images of the skeletal system without incurring significant radiation dose in patients referred for investigation of plasma cell dyscrasias.

METHODS

By using a single cadaver, 14 different whole-body low-dose CT protocols were individually assessed by 2 radiologists, blinded to acquisition parameters (kVp and mAs, reconstruction algorithm, dose reduction software). Combinations of kVps that range from 80-140 kVp, and tube current time product from 14-125 mAs were individually scored by using a Likert scale from 1-5 in 4 separate anatomical areas (skull base, thoracic spine, pelvis, and distal femora). Correlation between readers scores and effective doses were obtained by using correlation coefficient statistical analysis, statistical significance was considered P < .01. Interobserver agreement was assessed by using a Bland and Altman plot. Interobserver agreement in each of the 4 anatomical areas was assessed by using kappa statistics. A single set of parameters was then selected for use in future clinical trials in a cohort of patients referred for investigation of monoclonal gammopathy, including multiple myeloma.

RESULTS

Several sets of exposure parameters allowed low-dose whole-body CT to be performed with effective doses similar to skeletal survey while preserving diagnostic image quality. Individual reader's and average combined scores showed a strong inverse correlation with effective dose (reader 1, r = -0.78, P = .0001; reader 2, r = -0.75, P = .0003); average combined scores r = -0.81, P < .0001). Bland and Altman plot of overall scores shows reasonable interobserver agreement, with a mean difference of 1.055.

CONCLUSION

Whole-body low-dose CT can be used to obtain adequate CT image quality to assess normal osseous detail while delivering effective doses similar to those associated with conventional radiographic skeletal survey.

Prognostic significance of focal lesions in whole-body magnetic resonance imaging in patients with asymptomatic multiple myeloma

PURPOSE

With whole-body magnetic resonance imaging (wb-MRI), almost the whole bone marrow compartment can be examined in patients with monoclonal plasma cell disease. Focal lesions (FLs) detected by spinal MRI have been of prognostic significance in symptomatic multiple myeloma (sMM). In this study, we investigated the prognostic significance of FLs in wb-MRI in patients with asymptomatic multiple myeloma (aMM).

PATIENTS AND METHODS

Wb-MRI was performed in 149 patients with aMM. The prognostic significance of the presence and absence, as well as the number, of FLs for progression into sMM was analyzed.

RESULTS

FLs were present in 28% of patients. The presence per se of FLs and a number of greater than one FL were the strongest adverse prognostic factors for progression into sMM (P < .001) in multivariate analysis. A diffuse infiltration pattern in MRI, a monoclonal protein of 40 g/L or greater, and a plasma cell infiltration in bone marrow of 20% or greater were other adverse prognostic factors for progression-free survival in univariate analysis.

CONCLUSION

We recommend use of wb-MRI for risk stratification of patients with asymptomatic multiple myeloma.

Multiple myeloma

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

Role of radiography, MRI and FDG-PET/CT in diagnosing, staging and therapeutical evaluation of patients with multiple myeloma

Multiple myeloma is a malignant B-cell neoplasm that involves the skeleton in approximately 80% of the patients. With an average age of 60 years and a 5-years survival of nearly 45% Brenner et al. (Blood 111:2516–2520, 35) the onset is to be classified as occurring still early in life while the disease can be very aggressive and debilitating. In the last decades, several new imaging techniques were introduced. The aim of this review is to compare the different techniques such as radiographic survey, multidetector computed tomography (MDCT), whole-body magnetic resonance imaging (WB-MRI), fluorodeoxyglucose positron emission tomography- (FDG-PET) with or without computed tomography (CT), and ^99mTc-methoxyisobutylisonitrile (^99mTc-MIBI) scintigraphy. We conclude that both FDG-PET in combination with low-dose CT and whole-body MRI are more sensitive than skeleton X-ray in screening and diagnosing multiple myeloma. WB-MRI allows assessment of bone marrow involvement but cannot detect bone destruction, which might result in overstaging. Moreover, WB-MRI is less suitable in assessing response to therapy than FDG-PET. The combination of PET with low-dose CT can replace the golden standard, conventional skeletal survey. In the clinical practise, this will result in upstaging, due to the higher sensitivity.

Pathologic fractures in patients with multiple myeloma undergoing bisphosphonate therapy: incidence and correlation with course of disease

OBJECTIVE

The purposes of this study were single-center analysis of the incidence of pathologic fractures in patients with multiple myeloma undergoing bisphosphonate therapy and correlation of the occurrence of pathologic fractures with the course of disease.

MATERIALS AND METHODS

One hundred ninety-one patients with multiple myeloma consecutively underwent unenhanced whole-body low-dose MDCT in parallel with hematologic follow-up. Only patients undergoing at least two whole-body low-dose MDCT examinations were included in this retrospective study, resulting in 561 survey intervals. The median analysis period per patient was 23 months (range, 3-53 months). Fracture incidence and the relation between newly occurring fractures and course of the disease were assessed.

RESULTS

Forty-nine pathologic fractures were detected in 49 of the 561 survey intervals (8.7%) and in 36 of the 191 patients (19%). Fractures were found on MDCT images irrespective of disease course. They were found in 25 of 202 intervals (12.4%) of progressive disease, in 14 of 171 intervals (8.2%) of disease remission, and in 10 of 188 intervals (5.3%) of stable disease. The overall calculated annual incidence of pathologic fractures in patients with multiple myeloma was 14%. Eleven patients had more than one fracture, all of which were vertebral compression fractures. Three patients had three episodes of bone fracture, and eight patients had two episodes.

CONCLUSION

Pathologic fractures in patients with multiple myeloma undergoing bisphosphonate therapy occur independently of myeloma activity and therefore should not be considered a sign of disease progression.

Imaging response to systemic therapy for bone metastases

In patients with osteotropic primary tumours such as breast and prostate cancer, imaging treatment response of bone metastases is essential for the clinical management. After treatment of skeletal metastases, morphological changes, in particular of bone structure, occur relatively late and are difficult to quantify using conventional X-rays, CT or MRI. Early treatment response in these lesions can be assessed from functional imaging techniques such as dynamic contrast-enhanced techniques by MRI or CT and by diffusion-weighted MRI, which are quantifiable. Among the techniques within nuclear medicine, PET offers the acquisition of quantifiable parameters for response evaluation. PET, therefore, especially in combination with CT and MRI using hybrid techniques, holds great promise for early and quantifiable assessment of treatment response in bone metastases. This review summarises the classification systems and the use of imaging techniques for evaluation of treatment response and suggests parameters for the early detection and quantification of response to systemic therapy.

International myeloma working group consensus statement and guidelines regarding the current role of imaging techniques in the diagnosis and monitoring of multiple Myeloma

Several imaging technologies are used for the diagnosis and management of patients with multiple myeloma (MM). Conventional radiography, computed tomography (CT), magnetic resonance imaging (MRI) and nuclear medicine imaging are all used in an attempt to better clarify the extent of bone disease and soft tissue disease in MM. This review summarizes all available data in the literature and provides recommendations for the use of each of the technologies. Conventional radiography still remains the 'gold standard' of the staging procedure of newly diagnosed and relapsed myeloma patients. MRI gives information complementary to skeletal survey and is recommended in MM patients with normal conventional radiography and in all patients with an apparently solitary plasmacytoma of bone. Urgent MRI or CT (if MRI is not available) is the diagnostic procedure of choice to assess suspected cord compression. Bone scintigraphy has no place in the routine staging of myeloma, whereas sequential dual-energy X-ray absorptiometry scans are not recommended. Positron emission tomography/CT or MIBI imaging are also not recommended for routine use in the management of myeloma patients, although both techniques may be useful in selected cases that warrant clarification of previous imaging findings, but such an approach should ideally be made within the context of a clinical trial.

Myeloma bone disease: recent advances in biology, diagnosis, and treatment

Bone disease is a hallmark of multiple myeloma (MM). Occurring in the majority of MM patients, it is associated with bone pain, fractures, and hypercalcemia and has major impacts on quality of life. Furthermore, bone resorption activity has been shown to be an independent risk factor for overall survival in patients with symptomatic MM. Myeloma is characterized by a unique form of bone disease with lytic bone destruction that is not followed by reactive bone formation (uncoupling). This review focuses on recent advances in our understanding of the biology of osteoclast activation and osteoblast inhibition in MM, diagnostic standards, and recent progress in treatment options for myeloma bone disease. Translational research has enabled a rapid transfer of mechanistic insights from the bench to the bedside and will hopefully result in better treatment options and outcome for patients in near future.

Accuracy of whole-body low-dose multidetector CT (WBLDCT) versus skeletal survey in the detection of myelomatous lesions, and correlation of disease distribution with whole-body MRI (WBMRI)

AIM

The aim of the study is to assess the feasibility of whole-body low-dose computed tomography (WBLDCT) in the diagnosis and staging of multiple myeloma and compare to skeletal survey (SS), using bone marrow biopsy and whole-body magnetic resonance imaging (WBMRI; where available) as gold standard.

MATERIALS AND METHODS

Patients referred over an 18-month period for investigation of suspected multiple myeloma or restaging of myeloma were randomized to undergo one of two WBLDCT protocols using high kVp, low mAs technique (140 kVp, 14 mAs; or 140 kVp, 25 mAs). Recent WBMRI scans were reviewed in 23 cases. Each imaging modality was assessed by two radiologists in consensus and scored from 0-3 (0 = normal, 1 = 1-4 lesions, 2 = 5-20 lesions, 3 >or= 20 lesions/diffuse disease) in ten anatomical areas. Overall stage of disease, image quality score, and the degree of confidence of diagnosis were recorded. Diagnostic accuracy of skeletal survey and WBLDCT were determined using a gold standard of bone marrow biopsy and distribution of disease was compared to WBMRI.

RESULTS

Thirty-nine patients were evaluated. WBLDCT identified more osteolytic lesions than skeletal survey with a greater degree of diagnostic confidence and led to restaging in 18 instances (16 upstaged, two downstaged). In those with recent WBMRI, distribution of disease on WBLDCT showed superior correlation with WBMRI when compared with SS. Overall reader impression of stage on WBLDCT showed significant correlation with WBMRI (kappa = 0.454, p < 0.05). WBLDCT provided complementary information to WBMRI in nine patients with normal marrow signal following treatment response, but which were shown to have diffuse residual cortical abnormalities on CT.

CONCLUSION

WBLDCT at effective doses lower than previously reported, is superior to SS at detecting osteolytic lesions and at determining overall stage of multiple myeloma, and provides complementary information to WBMRI.

Hyperattenuating bone marrow abnormalities in myeloma patients using whole-body non-enhanced low-dose MDCT: correlation with haematological parameters

We aimed to establish the role of hyperattenuating medullary abnormalities detected by whole-body non-enhanced low-dose multidetector CT (WBLD-MDCT) in multiple myeloma (MM) patients referred for primary evaluation. 50 consecutive patients with untreated Stage I (n(I) = 11), Stage II (n(II) = 10) and Stage III (n(III) = 29) MM underwent WBLD-MDCT for staging. The number and size of osteolysis, as well as haematologic parameters including paraprotein and beta2-microglobulin levels, were assessed and related to the number, size and density of medullary abnormalities assumed to represent myeloma involvement. Bone marrow abnormalities were found in 2/11 (18%) Stage I, 6/10 (60%) Stage II and 20/29 (69%) Stage III myeloma patients, and did not parallel the incidence of osteolysis. Patients with medullary lesions had higher levels of immunoglobulin A (median, 4730 mg dl(-1) vs 1520 mg dl(-1)), light-chain proteinuria (median, 690 mg dl(-1) vs 214 mg dl(-1)) and IgG paraprotein (median, 3270 mg dl(-1) vs 2610 mg dl(-1)) compared with patients without medullary lesions. In patients with medullary abnormalities, levels of serum beta2-microglobulin were significantly higher than in patients without detectable marrow infiltrates (median, 4.3 mg dl(-1) vs 2.4 mg dl(-1); p = 0.0015). In conclusion, medullary abnormalities visualized by WBLD-MDCT are encountered in all stages of myeloma, including cases without osteolysis. They are associated with significantly elevated serum levels of paraprotein (reflecting tumour mass) and beta2-microglobulin, a prospective prognostic marker for myeloma. The nature and possible prognostic significance of medullary abnormalities detected by WBLD-MDCT therefore warrants further investigation.

Comparison of whole-body 64-slice multidetector computed tomography and conventional radiography in staging of multiple myeloma

This study compares the sensitivity of whole-body multidetector CT (MDCT) and conventional radiography (CR) in the staging of multiple myeloma (MM). Twenty-nine patients with MM underwent a staging examination both by MDCT and CR. CT examination was performed with a collimation of 64x0.6 mm, a tube potential of 100 kVp, an effective tube current-time product of 100 mAs and automatic dose modulation as low-dose protocol. Number, size and diagnostic confidence of osteolytic lesions were determined and compared. The effective dose of MDCT and CR was assessed. Using MDCT, the detection of osteolysis was increased seven-fold concerning the spine. Ninety-seven lesions in 18 patients were detected exclusively by MDCT. The detection rate concerning the spine, pelvic skeleton and thoracic cage was significantly higher (p< or =0.001), and diagnostic confidence was increased by MDCT (p<0.02) compared to CR. Therapy was changed after MDCT in 18.2% of the patients with a clinical suspicion of progressive disease. The estimated effective dose of MDCT (4.8 mSv) and CR (1.7 mSv) was comparable. In conclusion, MDCT has a significantly higher sensitivity and reliability in the detection of osteolysis than CR and can be recommended as standard imaging method in the staging of MM.

Can low-dose computed tomographic scan of the spine replace conventional radiography? An evaluation based on imaging myelomas, bone metastases, and fractures from osteoporosis

We evaluated and compared the radiological images of the spine of 111 patients affected by myeloma, bone metastases, and fractures secondary to osteoporosis demonstrated in low-dose computed tomographic (CT) scans and those demonstrated in conventional radiographic studies. From the analysis of the data obtained, it appears that the duration of the CT procedure is definitely shorter and that its diagnostic sensitivity is superior to that of conventional radiography. We should mention that the dose of radiation delivered by CT scanning does not constitute an unfavorable element in patients, usually elderly, for whom CT scanning was indicated.

Efficacy of multidetector row computed tomography of the spine in patients with multiple myeloma: comparison with magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography

PURPOSE

The aim of our study was to compare the efficacy of multidetector row computed tomography (MDCT) with magnetic resonance imaging (MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET) for detection of spinal bone marrow involvement in patients with multiple myeloma.

MATERIALS AND METHODS

Ten patients with multiple myeloma stage III underwent MDCT and MRI of the spine and FDG-PET. The number and location of lesions detected by 3 modalities were recorded, and a lesion-by-lesion analysis was completed, using McNemar test. For MDCT, image analysis was performed according to the type of lesion (established by Laroche et al), and the efficacy of lesion detection was compared with that of the MRI and FDG-PET. P values less than 0.05 were considered statistically significant.

RESULTS

The MDCT, MRI, and FDG-PET detected the following numbers of lesions: 102 of 140 vertebrae, 95 of 140 vertebrae, and 84 of 140 vertebrae, respectively. The difference between the abilities of MDCT and MRI to detect lesions was not statistically significant (P = 0.289). However, the difference in effectiveness between MDCT and FDG-PET was statistically significant (P < 0.001). For small osteolytic lesions, less than 5 mm, the difference in effectiveness between MDCT and MRI was also statistically significant (P = 0.031).

CONCLUSIONS

The MDCT is very sensitive in detecting small osteolytic lesions in the spine, as compared with MRI and FDG-PET.

The benefit of using whole-body, low-dose, nonenhanced, multidetector computed tomography for follow-up and therapy response monitoring in patients with multiple myeloma

BACKGROUND

The objectives of this study were to assess the status and clinical course of patients with multiple myeloma based on the direct visualization of changes in medullary, extramedullary, and focal osteolytic myeloma involvement by using whole-body, low-dose, multidetector computed tomography (WBLD-MDCT) and to compare those results with an assessment based on conventional hematologic parameters.

METHODS

Between June 2002 and December 2005, WBLD-MDCT scans were obtained from 131 consecutive multiple myeloma patients with or without therapy, resulting in a total of 439 examinations. The number and size of osteolytic lesions and the number, size, and density of focal or diffuse medullary and extramedullary lesions were analyzed. Those results and the results at follow-up were related to current laboratory tests for myeloma. Validation was achieved by the combined reading of both hematologic and radiologic parameters at follow-up.

RESULTS

Association between both diagnostic modalities was assessed by using European Group for Blood and Marrow Transplantation response criteria, resulting in an agreement of kappa = 0.70. Hematologic parameters proved correct in 84% of all examinations, whereas WBLD-MDCT resulted in correct assessment in 94% of all examinations. Among 91 of 439 examinations that produced discrepant findings (21%), WBLD-MDCT proved correct in 68 of 91 examinations (75%), as determined at further follow-up (95% confidence interval, 66-83%; P = .000003; sign test). The combination of WBLD-MDCT with conventional, laboratory-based follow-up resulted in significantly greater diagnostic accuracy compared with laboratory testing alone.

CONCLUSIONS

The results from this study indicated that WBLD-MDCT represents a reliable, imaging-based method for the direct monitoring of the course of patients with myeloma under specific therapy, and it showed good concordance with established hematologic parameters. It is noteworthy that, in the current investigation, WBLD-MDCT proved to be even more reliable than conventional, laboratory-based follow-up.

Guidelines for the use of imaging in the management of myeloma

In 2001, reference to the use of imaging in the British Committee for Standards in Haematology guidelines for the diagnosis and management of myeloma was confined to the standard use of plain X-rays in the diagnostic skeletal survey and emergency use of computed tomography (CT) and magnetic resonance (MR) imaging in the setting of cord compression. Since then, there has been a steady rise in interest in the use of various imaging techniques in the management of myeloma. The purpose of imaging in the management of myeloma includes the assessment of the extent and severity of the disease at presentation, the identification and characterisation of complications, and the assessment of response to therapy. Plain radiography, CT, and MR imaging are generally established examination techniques in myeloma whilst positron emission tomography (PET) and (99)Technetium sestamibi (MIBI) imaging are promising newer scanning techniques under current evaluation. These stand-alone imaging guidelines discuss recommendations for the use of each modality of imaging at diagnosis and in the follow up of patients with myeloma.

Problems monitoring response in multiple myeloma

There has been a revolution in the treatment of multiple myeloma over the past decade. This article seeks to correlate advances in imaging with advances in treatment and to highlight how proper understanding of both is necessary for optimum management.