Magnetic Resonance Imaging of the Bone Marrow in Hematologic Malignancies

Sensitivity and Specificity of Whole-body MRI for the Detection of Pediatric Malignancy

Children with cancer often present with general and nonspecific symptoms leading to initial diagnostic workup inclusive of clinical imaging. Various sequences of magnetic resonance imaging (MRI) are becoming more available for diagnostic imaging. However, there is currently a dearth of literature quantifying the sensitivity and specificity of whole-body MRI in identifying pediatric malignancy. In this study, a retrospective analysis was performed of pediatric whole-body MRI inclusive of short tau inversion recovery sequence conducted at an academic pediatric medical center from 2013 to 2018. Kappa statistics were used to evaluate the diagnostic agreement between MRI results and the gold standard diagnostic study of the respective final diagnosis. Sensitivity, specificity, false-positive, and false-negative estimates were provided with joint 90% confidence regions. One hundred forty-two patients received a whole-body MRI during the study period. The sensitivity of whole-body MRI in detecting malignancy was found to be 93.8% with a specificity of 93.4%. The positive and negative predictive values were determined to be 65.2% and 99.1%, respectively. Our findings suggest that whole-body MRI may be of value as an initial diagnostic tool for pediatric malignancy. Larger multicenter collaboration will be needed to further support these data.

Study of bone marrow microstructure in healthy young adults using intravoxel incoherent motion diffusion-weighted MRI

Bone marrow is one of the most important organs in the human body. The evaluation of bone marrow microstructure and gender-related cellular and capillary networks in healthy young adults can help to better understand the process of bone metabolism. Intravoxel incoherent motion (IVIM) provides both diffusion and perfusion quantifications without requiring intravenous contrast agent injection. In this prospective study, 60 healthy young age-matched volunteers (30 men and 30 women) underwent MRI scans at 1.5 T using multi-b-value diffusion-weighted imaging on sagittal planes covering the lumbar bone marrow. The apparent diffusion coefficient (ADC), true ADC (D), pseudo-ADC (D*), and perfusion fraction (f) were calculated from the diffusion-weighted images using the mono- and bi-exponential models. Lumbar cancellous bone (L2-L4) was selected as the region of interest. An independent t-test was used to detect significant differences in ADC values and IVIM parameters between men and women. The differences in IVIM parameters among the L2, L3, and L4 groups were compared with analysis of variance. The D and f values in women were significantly higher than that in men (p = 0.001, 0.026). However, D* was significantly lower in women than that in men (p = 0.001). Furthermore, there was no significant gender difference for the conventional ADC value (p = 0.186). Moreover, there were no significant differences in the D, f, and D* values among the L2, L3, and L4 vertebras of women or men. IVIM parameters can show differences in bone marrow between young women and men. As a non-invasive method, it can assess bone marrow microstructure, such as cellularity and perfusion.

The Pediatric Spine

The spine, a frequently investigated site in children, has a complex development in relation to both nervous and bone/cartilaginous structures and shows several particular features in children compared with adults. We report the main normal variants and pathologies of the pediatric spine, from the prenatal period to adolescence, focusing on a multimodality imaging approach.

"Wrap-Around Sign" in Non-Hodgkin Lymphoma of the Spine: A Common yet Overlooked Imaging Feature?

BACKGROUND

Anecdotal cases of the so-called "wrap-around" appearance in non-Hodgkin lymphoma (NHL) of the spine exist in the medical literature. In this paper, we looked at the prevalence of this imaging feature in our institutional cases.

MATERIALS AND METHODS

We screened our institutional database for biopsy-proven NHL. Our inclusion criteria were the histologically confirmed diagnosis of NHL involving any vertebra, available magnetic resonance imaging of the affected site, and a positive wrap-around sign. Exclusion criteria included lymphoma cases without the wrap-around sign and/or histology other than NHL. We subdivided the cases into 3 groups: 1) lymphoma wrapped around the vertebral body; 2) the posterior elements alone; or 3) both the vertebral body and posterior elements.

RESULTS

Our search identified 147 cases of NHL in which a confirmatory biopsy at the primary tumor site was available. Of those, 23 cases fulfilled the inclusion criteria (16 men and 7 women with average age at diagnosis of 63.3 years), yielding prevalence of 15.6% in our series. Most commonly the lymphoma involved the vertebral body with or without some involvement of the posterior vertebral elements (n = 20, 86.9%), followed by posterior vertebral elements (n = 2, 8.7%). One remaining case (4.4%) had lymphoma involving the anterior vertebral body and posterior elements.

CONCLUSIONS

Findings of our pilot study indicated that the wrap-around sign in cases of NHL could be helpful diagnostically. This sign may be frequently under-recognized, leading to potential for a diagnostic dilemma on imaging. Larger studies are necessary to obtain more precise information about the prevalence of the wrap-around sign.

Bone marrow necrosis in pediatric malignancies: 10-Year retrospective review and review of literature

Bone marrow necrosis (BMN) is a rare pathologic finding, but when encountered is most often associated with malignancy. In adults, its presence correlates with an inferior prognosis, however in children the prognostic implication is unclear. We performed a retrospective review of 3,760 bone marrow specimens in patients ≤18 years over a 10-year period. BMN was identified in less than 1% of specimens and only in patients with leukemia, lymphoma, or neuroblastoma. BMN contributed to a delay in diagnosis; however, advanced medical imaging may serve as a tool to localize nonnecrotic areas for bone marrow sampling, facilitating an expedited diagnosis.

Comparison of PET/CT and MRI in the Diagnosis of Bone Metastasis in Prostate Cancer Patients: A Network Analysis of Diagnostic Studies

BACKGROUND

Accurate diagnosis of bone metastasis status of prostate cancer (PCa) is becoming increasingly more important in guiding local and systemic treatment. Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) have increasingly been utilized globally to assess the bone metastases in PCa. Our meta-analysis was a high-volume series in which the utility of PET/CT with different radioligands was compared to MRI with different parameters in this setting.

MATERIALS AND METHODS

Three databases, including Medline, Embase, and Cochrane Library, were searched to retrieve original trials from their inception to August 31, 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. The methodological quality of the included studies was assessed by two independent investigators utilizing Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). A Bayesian network meta-analysis was performed using an arm-based model. Absolute sensitivity and specificity, relative sensitivity and specificity, diagnostic odds ratio (DOR), and superiority index, and their associated 95% confidence intervals (CI) were used to assess the diagnostic value.

RESULTS

Forty-five studies with 2,843 patients and 4,263 lesions were identified. Network meta-analysis reveals that 68Ga-labeled prostate membrane antigen (68Ga-PSMA) PET/CT has the highest superiority index (7.30) with the sensitivity of 0.91 and specificity of 0.99, followed by 18F-NaF, 11C-choline, 18F-choline, 18F-fludeoxyglucose (FDG), and 18F-fluciclovine PET/CT. The use of high magnetic field strength, multisequence, diffusion-weighted imaging (DWI), and more imaging planes will increase the diagnostic value of MRI for the detection of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT was performed in the detection of bone metastasis on patient-based level (sensitivity, 0.94 vs. 0.91; specificity, 0.94 vs. 0.96; superiority index, 4.43 vs. 4.56).

CONCLUSIONS

68Ga-PSMA PET/CT is recommended for the diagnosis of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT should be performed in the detection of bone metastasis.

Autoimmune myelofibrosis associated with systemic lupus erythematosus: a case report

A 66-year-old woman presented with severe anaemia, thrombocytopenia and lymphopenia. The bone marrow biopsy demonstrated hypocellular marrow with myelofibrosis (MF); there was no evidence of malignancy, but infiltration of peripheral T and B cells were noticed. Magnetic resonance imaging (MRI) revealed that bone marrow of the spine exhibited low signal intensity (SI) with spotty high SI in T1- and T2-weighted images. Because there was evidence of autoimmune abnormality, she had fulfilled the classification criteria for systemic lupus erythematosus (SLE). She was diagnosed with autoimmune myelofibrosis (AIMF) associated with SLE and was treated with corticosteroid. Cytopenia improved after 1 month of corticosteroid therapy. A repeated bone marrow biopsy demonstrated that cellularity had increased and that the amount of reticulin fibre had reduced after treatment. Compared with primary MF, AIMF has generally a favourable prognosis and is often associated with autoimmune diseases, especially SLE. Bone marrow biopsy, but not aspiration, was useful for diagnosing bone marrow fibrosis. Although the association between SLE and MF has been rarely reported, we should pay attention to MF as a possible cause of pancytopenia.

Multiple Myeloma Associated Bone Disease

The lytic bone disease is a hallmark of multiple myeloma, being present in about 80% of patients with newly diagnosed MM, and in more during the disease course. The myeloma associated bone disease (MBD) severely affects the morbidity and quality of life of the patients. MBD defines treatment demanding MM. In recent years, knowledge of the underlying pathophysiology has increased, and novel imaging technologies, medical and non-pharmaceutical treatments have improved. In this review, we highlight the major achievements in understanding, diagnosing and treating MBD. For diagnosing MBD, low-dose whole-body CT is now recommended over conventional skeletal survey, but also more advanced functional imaging modalities, such as diffusion-weighted MRI and PET/CT are increasingly important in the assessment and monitoring of MBD. Bisphosphonates have, for many years, played a key role in management of MBD, but denosumab is now an alternative to bisphosphonates, especially in patients with renal impairment. Radiotherapy is used for uncontrolled pain, for impeding fractures and in treatment of impeding or symptomatic spinal cord compression. Cement augmentation has been shown to reduce pain from vertebral compression fractures. Cautious exercise programs are safe and feasible and may have the potential to improve the status of patients with MM.

Intravital imaging of megakaryocytes

The dynamics of platelet formation could only be investigated since the development of two-photon microscopy in combination with suitable fluorescent labeling strategies. In this review paper, we give an overview of recent advances in fluorescence imaging of the bone marrow that have contributed to our understanding of platelet biogenesis during the last decade. We make a brief survey through the perspectives and limitations of today's intravital imaging, but also discuss complementary methods that may help to piece together the puzzle of megakaryopoiesis and platelet formation.

Evaluating and monitoring bone marrow hypoplasia in adults with aplastic anemia via high-resolution iliac magnetic resonance imaging in the current era

The diagnosis and monitoring of aplastic anemia (AA) rely heavily on a complete blood count (CBC), and multiple-site bone marrow (BM) aspirations and biopsies. However, these approaches have certain limitations. We aimed to assess high-resolution magnetic resonance imaging (MRI) as a complementary approach for evaluating BM hypoplasia and monitoring treatment response in adults with AA in the current era.Twelve newly diagnosed AA patients and 12 sex- and age-matched healthy controls were enrolled in this study from January 2017 to August 2018. A bilateral iliac 3.0T MRI was used to collect data for each subject, and the signal intensity on the T1-weighted images (T1WIs) were expressed as a contrast-to-noise ratio (CNR). The MRI, CBC, and BM biopsy data were analyzed and compared.A qualitative analysis identified a significant difference in MRI signal characteristics between the AA group and the healthy control group. The clinical classifications of very severe aplastic anemia (VSAA) and severe aplastic anemia (SAA) corresponded to pattern I and pattern II on the MR images, respectively. However, this imaging classification did not correlate with the biopsy-based BM cellularity measure. A quantitative analysis showed a significantly higher signal intensity in AA patients than in controls. A within-group comparison revealed that more severe types of AA, based on the clinical classification, corresponded to stronger signals. Notably, MRI could detect treatment response earlier than CBC, regardless of whether there were improvements in hematopoiesis.MRI can be used to predict the therapeutic effects in patients with AA and is an important complementary tool for evaluating and monitoring BM hypoplasia.

Bone Marrow Adipose Tissue Quantification by Imaging

PURPOSE OF REVIEW

The significance and roles of marrow adipose tissue (MAT) are increasingly known, and it is no more considered a passive fat storage but a tissue with significant paracrine and endocrine activities that can cause lipotoxicity and inflammation.

RECENT FINDINGS

Changes in the MAT volume and fatty acid composition appear to drive bone and hematopoietic marrow deterioration, and studying it may open new horizons to predict bone fragility and anemia development. MAT has the potential to negatively impact bone volume and strength through several mechanisms that are partially described by inflammaging and lipotoxicity terminology. Evidence indicates paramount importance of MAT in age-associated decline of bone and red marrow structure and function. Currently, MAT measurement is being tested and validated by several techniques. However, purpose-specific adaptation of existing imaging technologies and, more importantly, development of new modalities to quantitatively measure MAT are yet to be done.

Imaging the Vascular Bone Marrow Niche During Inflammatory Stress

RATIONALE

Inflammatory stress induced by exposure to bacterial lipopolysaccharide causes hematopoietic stem cell expansion in the bone marrow niche, generating a cellular immune response. As an integral component of the hematopoietic stem cell niche, the bone marrow vasculature regulates the production and release of blood leukocytes, which protect the host against infection but also fuel inflammatory diseases.

OBJECTIVE

We aimed to develop imaging tools to explore vascular changes in the bone marrow niche during acute inflammation.

METHODS AND RESULTS

Using the TLR (Toll-like receptor) ligand lipopolysaccharide as a prototypical danger signal, we applied multiparametric, multimodality and multiscale imaging to characterize how the bone marrow vasculature adapts when hematopoiesis boosts leukocyte supply. In response to lipopolysaccharide, ex vivo flow cytometry and histology showed vascular changes to the bone marrow niche. Specifically, proliferating endothelial cells gave rise to new vasculature in the bone marrow during hypoxic conditions. We studied these vascular changes with complementary intravital microscopy and positron emission tomography/magnetic resonance imaging. Fluorescence and positron emission tomography integrin αVβ3 imaging signal increased during lipopolysaccharide-induced vascular remodeling. Vascular leakiness, quantified by albumin-based in vivo microscopy and magnetic resonance imaging, rose when neutrophils departed and hematopoietic stem and progenitor cells proliferated more vigorously.

CONCLUSIONS

Introducing a tool set to image bone marrow either with cellular resolution or noninvasively within the entire skeleton, this work sheds light on angiogenic responses that accompany emergency hematopoiesis. Understanding and monitoring bone marrow vasculature may provide a key to unlock therapeutic targets regulating systemic inflammation.

3D Monte Carlo bone marrow dosimetry for Lu-177-PSMA therapy with guidance of non-invasive 3D localization of active bone marrow via Tc-99m-anti-granulocyte antibody SPECT/CT

BACKGROUND

The bone marrow (BM) is a main risk organ during Lu-177-PSMA ligand therapy of metastasized castration-resistant prostate cancer (mCRPC) patients. So far, BM dosimetry relies on S values, which are pre-computed for reference anatomies, simplified activity distributions, and a physiological BM distribution. However, mCRPC patients may show a considerable bone lesion load, which leads to a heterogeneous and patient-specific activity accumulation close to BM-bearing sites. Furthermore, the patient-specific BM distribution might be significantly altered in the presence of bone lesions. The aim was to perform BM absorbed dose calculations through Monte Carlo (MC) simulations and to investigate the potential value of image-based BM localization. This study is based on 11 Lu-177-PSMA-617 therapy cycles of 10 patients (10 first cycles), who obtained a pre-therapeutic Ga-68-PSMA-11 PET/CT; quantitative Lu-177 SPECT acquisitions of the abdomen 24 (+CT), 48, and 72 h p.i.; and a Lu-177 whole-body planar acquisition at 24 h post-therapy. Patient-specific 3D volumes of interest were segmented from the Ga-68-PSMA-11 PET/CT, filled with activity information from the Lu-177 data, and imported into the FLUKA MC code together with the patient CT. MC simulations of the BM absorbed dose were performed assuming a physiological BM distribution according to the ICRP 110 reference male (MC1) or a displacement of active BM from the direct location of bone lesions (MC2). Results were compared with those from S values (SMIRD). BM absorbed doses were correlated with the decrease of lymphocytes, total white blood cells, hemoglobin level, and platelets. For two patients, an additional pre-therapeutic Tc-99m-anti-granulocyte antibody SPECT/CT was performed for BM localization.

RESULTS

Median BM absorbed doses were 130, 37, and 11 mGy/GBq for MC1, MC2, and SMIRD, respectively. Significant strong correlation with the decrease of platelet counts was found, with highest correlation for MC2 (MC1: r = - 0.63, p = 0.04; MC2: r = - 0.71, p = 0.01; SMIRD: r = - 0.62, p = 0.04). For both investigated patients, BM localization via Tc-99m-anti-granulocyte antibody SPECT/CT indicated a displacement of active BM from the direct location of lesions similar to model MC2 and led to a reduction in the BM absorbed dose of 40 and 41% compared to MC1.

CONCLUSION

Higher BM absorbed doses were observed for MC-based models; however, for MC2, all absorbed doses were still below 2 Gy. MC1 resulted in critical values for some patients, but is suspected to yield strongly exaggerated absorbed doses by neglecting bone marrow displacement. Image-based BM localization might be beneficial, and future studies are recommended to support an improvement for the prediction of hematoxicities.

Bone marrow abnormalities detected by magnetic resonance imaging as initial sign of hematologic malignancies

The increasing use of radiological examination, especially magnetic resonance imaging (MRI), will probably increase the risk of unintended discovery of bone marrow abnormalities in patients where a hematologic disease would not be expected. In this paper we present four patients with different hematologic malignancies of nonplasma cell types. In all patients the MRI bone marrow abnormalities represent an initial presentation of the disease. These case reports illustrate the importance of a careful diagnostic follow-up without delay of patients with MRI bone marrow abnormalities, because such abnormalities can represent the first sign of both acute promyelocytic leukemia as well as other variants of acute leukemia.

Age- and Sex-dependent Frequency of Fat Metaplasia and Other Structural Changes of the Sacroiliac Joints in Patients without Axial Spondyloarthritis: A Retrospective, Cross-sectional MRI Study

OBJECTIVE

To determine the prevalence of fat metaplasia and other structural lesions of the sacroiliac joints associated with axial spondyloarthritis in a nonrheumatological patient population.

METHODS

Magnetic resonance imaging examinations that included the pelvis and were performed in patients without known rheumatological disease were used for this retrospective cross-sectional study. These images were evaluated for sacroiliac fat metaplasia, sclerosis, osteophytes, and joint space alterations such as erosions or ankylosis. Patients were divided into 7 age groups (15-24 to ≥ 75 yrs). Prevalence of lesions across age groups was calculated. Possible clinical confounders (e.g., status post radiation, suspected inflammatory bowel disease) were investigated regarding their effect on lesion prevalence and extent, to exclude bias.

RESULTS

A total of 485 patients were enrolled. Fat metaplasia was very common and increased with age, from a prevalence of 50.6% in the age groups < 45, to 94.4% in patients ≥ 75 years. Erosions were uncommon: 0.6% of patients < 45, and 2.6% of the entire study population exhibited this feature, with no detectable age-dependent increase. Sclerosis and osteophytes were detected in 13.7% and 37.0% of patients, respectively. None of the investigated clinical confounders had a significant effect on lesion prevalence.

CONCLUSION

Our study shows a very high prevalence of fat metaplasia adjacent to the sacroiliac joint in asymptomatic patients, while erosions are extremely uncommon.

Whole-body MRI, dynamic contrast-enhanced MRI, and diffusion-weighted imaging for the staging of multiple myeloma

Magnetic resonance imaging (MRI) is the most sensitive imaging technique for the detection of bone marrow infiltration, and has therefore recently been included in the new diagnostic myeloma criteria, as proposed by the International Myeloma Working Group. Nevertheless, conventional MRI only provides anatomical information and is therefore only of limited use in the response assessment of patients with multiple myeloma. The additional information from functional MRI techniques, such as diffusion-weighted imaging and dynamic contrast-enhanced MRI, can improve the detection rate of bone marrow infiltration and the assessment of response. This can further enhance the sensitivity and specificity of MRI in the staging of multiple myeloma patients. This article provides an overview of the technical aspects of conventional and functional MRI techniques with practical recommendations. It reviews the diagnostic performance, prognostic value, and role in therapy assessment in multiple myeloma and its precursor stages.

Measurement of vertebral bone marrow proton density fat fraction in children using quantitative water-fat MRI

OBJECTIVES

To investigate the feasibility of employing a 3D time-interleaved multi-echo gradient-echo (TIMGRE) sequence to measure the proton density fat fraction (PDFF) in the vertebral bone marrow (VBM) of children and to examine cross-sectional changes with age and intra-individual variations from the lumbar to the cervical region in the first two decades of life.

MATERIALS AND METHODS

Quantitative water-fat imaging of the spine was performed in 93 patients (49 girls; 44 boys; age median 4.5 years; range 0.1-17.6 years). For data acquisition, a six-echo 3D TIMGRE sequence was used with phase correction and complex-based water-fat separation. Additionally, single-voxel MR spectroscopy (MRS) was performed in the L4 vertebrae of 37 patients. VBM was manually segmented in the midsagittal slice of each vertebra. Univariable and multivariable linear regression models were calculated between averaged lumbar, thoracic and cervical bone marrow PDFF and age with adjustments for sex, height, weight, and body mass index percentile.

RESULTS

Measured VBM PDFF correlated strongly between imaging and MRS (R ² = 0.92, slope = 0.94, intercept = -0.72%). Lumbar, thoracic and cervical VBM PDFF correlated significantly (all p < 0.001) with the natural logarithm of age. Differences between female and male patients were not significant (p > 0.05).

CONCLUSION

VBM development in children showed a sex-independent cross-sectional increase of PDFF correlating with the natural logarithm of age and an intra-individual decrease of PDFF from the lumbar to the cervical region in all age groups. The present results demonstrate the feasibility of using a 3D TIMGRE sequence for PDFF assessment in VBM of children.

Radiographic features of plasma cell leukemia in the maxilla: A case report

Plasma cell leukemia (PCL) is an aggressive form of multiple myeloma where there is hematogenous spread of abnormal plasma cells into the periphery. This is opposed to multiple myeloma, where the abnormal plasma cells stay in the bone marrow. PCL is more common in males than females, and is also more common in African-Americans than Caucasians. Signs and symptoms of PCL include, but are not limited to, renal insufficiency, hypercalcemia, anemia, lytic bone lesions, thrombocytopenia, hepatomegaly, and splenomegaly. Here, we discussed a case of a 71-year-old Caucasian female recently diagnosed with primary PCL with radiographic features of this disease throughout the body, with an emphasis on the maxillofacial skeleton and relevance from a dental standpoint.

New Landmark for Localizing the Site of the Subdental Synchondrosis Remnant: Application to Discerning Pathology from Normal on Imaging

OBJECTIVE

We hypothesized that the entry site of the basivertebral vein into the basivertebral foramen of C2 might localize the subdental synchondrosis between the odontoid process and body of C2, which may be helpful for odontoid fracture classification.

METHODS

Twenty-five dry adult C2 specimens underwent thin-cut computed tomography and were sectioned sagittally. The basivertebral foramen was then correlated to internal bony anatomy. Fifty magnetic resonance images were reviewed, and the location of the subdental synchondrosis was determined.

RESULTS

A basivertebral foramen was identified on the posterior surface of all dry C2 specimens. The openings were found at a distance of 30%-44% on an inferosuperior point along the vertical height of C2. For bony specimens with a subdental synchondrosis remnant (75%), entry of acupuncture needles into the basivertebral foramen was always directly at the level of the synchondrosis remnant. For magnetic resonance imaging (MRI), a subdental synchondrosis or its remnants were seen on all studies. The distance from the base of C2 to the subdental synchondrosis ranged from 9-13 mm. This equated to an inferosuperior point 32%-43% along the vertical height of C2. A strong correlation existed when comparing the location of the basivertebral foramen of bony specimens and the subdental synchondrosis location on MRI.

CONCLUSIONS

The basivertebral foramen is a consistently present anatomic reference point for the subdental synchondrosis even if the latter cannot be seen on conventional radiographic imaging. Our MRI data might also be useful in helping differentiate lesions affecting C2 from normal subdental cartilaginous remnants that can be encountered on imaging.

The trends and challenges in orthopaedic simulation

Generally, in some universities of medicine, orthopaedic training procedures represent a difficult task due to the inadequacies of the systems, the resources, and the use of technologies. This article explains the challenges and the needs for more research in the issue of orthopaedic simulation around the world.

18F-FDG PET/CT, 99mTc-MIBI, and MRI in the prediction of outcome of patients with multiple myeloma: a comparative study

PURPOSE

The aim of this study was to compare the relative contribution of 18F-FDG PET/CT, 99mTc-MIBI, and MRI in predicting progression-free survival (PFS) and overall survival (OS) in multiple myeloma (MM) patients.

PATIENTS AND METHODS

Thirty-three newly diagnosed MM patients had been evaluated in a previous study by 18F-FDG PET/CT, 99mTc-MIBI, and spine and pelvis MRI reporting focal lesions and diffuse bone marrow involvement. Twenty-seven patients were then subjected to a mean follow-up period of 58 months, whereas 6 patients were lost.

RESULTS

18F-FDG PET/CT, 99mTc-MIBI, and MRI were positive in 26, 24, and 22 patients, respectively, showing diffuse bone marrow involvement in 12, 21, and 17 patients and a total of 185, 56, and 39 focal lesions, respectively. At follow-up, 18 patients showed complete or partial remission, whereas 9 patients developed progressive disease, 7 of which died of myeloma. Univariate and subsequent multivariate analysis showed that F-FDG PET/CT focal uptake and Tc-MIBI focal and diffuse uptake predicted PFS (P = 0.0006), whereas 18F-FDG PET/CT focal uptake and 99mTc-MIBI focal uptake predicted OS (P = 0.0010). Although MRI diffuse pattern predicted PFS at univariate analysis (P = 0.0376), it was not retained in the model at multivariate analysis. Receiver operating characteristic curve analysis showed that the number of focal lesions best discriminating for PFS and OS prediction was 4 and 11 for 18F-FDG PET/CT and 2 in both cases for 99mTc-MIBI, respectively. By Kaplan-Meier analysis and log-rank testing, PFS and OS at follow-up were significantly better in patients showing a number of focal lesions at F-FDG PET/CT or Tc-MIBI lower than the respective cutoff (P = 0.03, P = 0.004, and P < 0.0001, respectively). Finally, PFS was significantly better in patients showing absent/faint diffuse Tc-MIBI uptake than in those having moderate/intense diffuse uptake (P = 0.0012).

CONCLUSIONS

18F-FDG PET/CT and 99mTc-MIBI may be useful in predicting PFS and OS in myeloma patients.

Quantitative Analysis of MR Imaging to Assess Treatment Response for Patients with Multiple Myeloma by Using Dynamic Intensity Entropy Transformation: A Preliminary Study

PURPOSE

To develop a quantitative measure of bone marrow changes in magnetic resonance (MR) images and investigate its capability for assessment of treatment response for patients with multiple myeloma (MM).

MATERIALS AND METHODS

This study was retrospective, institutional review board approved, and HIPAA compliant. Informed consent was waived. Patients (n = 64; mean age, 58.8 years [age range, 27-75 years]) who were diagnosed with MM and underwent autologous bone marrow stem cell transplantation (BMT) were evaluated. A pair of spinal MR examinations performed before and after BMT was collected from each patient's records. A three-dimensional dynamic intensity entropy transformation (DIET) method was developed to transform MR T1-weighted signal voxel by voxel to a quantitative entropy enhancement value (qEEV), from which predictor variables were derived to train a linear discriminant analysis classifier by using a leave-one-out method. The output of the linear discriminant analysis provided a qEEV-based response index for quantitative assessment of treatment response. The performance of quantitative response index for the discrimination of responder and nonresponder patients was evaluated by receiver operating characteristic curve analysis.

RESULTS

Among the 46 and 18 clinically diagnosed responder and nonresponder patients, the quantitative response index at a chosen decision threshold correctly identified 42 responder and 17 nonresponder patients. The agreement between the DIET method and the clinical outcome reached 0.922 (59 of 64; κ = 0.816; area under the receiver operating characteristic curve, 0.886 ± 0.042).

CONCLUSION

This study demonstrated the feasibility of quantitative response index to differentiate responder and nonresponder patients and had substantial agreement with clinical outcomes, which indicated that this quantitative measure has the potential to be an image biomarker to assess MM treatment response.

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.

Incidence and evaluation of incidental abnormal bone marrow signal on magnetic resonance imaging

Purpose. The increased use of magnetic resonance imaging (MRI) has resulted in reports of incidental abnormal bone marrow (BM) signal. Our goal was to determine the evaluation of an incidental abnormal BM signal on MRI and the prevalence of a subsequent oncologic diagnosis. Methods. We conducted a retrospective cohort study of patients over age 18 undergoing MRI between May 2005 and October 2010 at Tufts Medical Center (TMC) with follow-up through November 2013. The electronic medical record was queried to determine imaging site, reason for scan, evaluation following radiology report, and final diagnosis. Results. 49,678 MRIs were done with 110 patients meeting inclusion criteria. Twenty two percent underwent some evaluation, most commonly a complete blood count, serum protein electrophoresis, or bone scan. With median follow-up of 41 months, 6% of patients were diagnosed with malignancies including multiple myeloma, non-Hodgkins lymphoma, metastatic non-small cell lung cancer, and metastatic adenocarcinoma. One patient who had not undergone evaluation developed breast cancer 24 months after the MRI. Conclusions. Incidentally noted abnormal or heterogeneous bone marrow signal on MRI was not inconsequential and should prompt further evaluation.

Gradient-echo in-phase and opposed-phase chemical shift imaging: role in evaluating bone marrow

Chemical shift imaging (CSI) provides valuable information for assessing the bone marrow, while adding little to total examination time. In this article, we review the uses of CSI for evaluating bone marrow abnormalities. CSI can be used for differentiating marrow-replacing lesions from a range of non-marrow-replacing processes, although the sequence is associated with technical limitations and pitfalls. Particularly at 3 T, susceptibility artefacts are prevalent, and optimal technical parameters must be implemented with appropriate choices for echo times.

(18)F-FDG-PET/CT imaging in an IL-6- and MYC-driven mouse model of human multiple myeloma affords objective evaluation of plasma cell tumor progression and therapeutic response to the proteasome inhibitor ixazomib

(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography (CT) are useful imaging modalities for evaluating tumor progression and treatment responses in genetically engineered mouse models of solid human cancers, but the potential of integrated FDG-PET/CT for assessing tumor development and new interventions in transgenic mouse models of human blood cancers such as multiple myeloma (MM) has not been demonstrated. Here we use BALB/c mice that contain the newly developed iMyc(ΔEμ) gene insertion and the widely expressed H2-L(d)-IL6 transgene to demonstrate that FDG-PET/CT affords an excellent research tool for assessing interleukin-6- and MYC-driven plasma cell tumor (PCT) development in a serial, reproducible and stage- and lesion-specific manner. We also show that FDG-PET/CT permits determination of objective drug responses in PCT-bearing mice treated with the investigational proteasome inhibitor ixazomib (MLN2238), the biologically active form of ixazomib citrate (MLN9708), that is currently in phase 3 clinical trials in MM. Overall survival of 5 of 6 ixazomib-treated mice doubled compared with mice left untreated. One outlier mouse presented with primary refractory disease. Our findings demonstrate the utility of FDG-PET/CT for preclinical MM research and suggest that this method will play an important role in the design and testing of new approaches to treat myeloma.

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.

Fat fraction bias correction using T1 estimates and flip angle mapping

PURPOSE

To develop a new method of reducing T1 bias in proton density fat fraction (PDFF) measured with iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL).

MATERIALS AND METHODS

PDFF maps reconstructed from high flip angle IDEAL measurements were simulated and acquired from phantoms and volunteer L4 vertebrae. T1 bias was corrected using a priori T1 values for water and fat, both with and without flip angle correction. Signal-to-noise ratio (SNR) maps were used to measure precision of the reconstructed PDFF maps. PDFF measurements acquired using small flip angles were then compared to both sets of corrected large flip angle measurements for accuracy and precision.

RESULTS

Simulations show similar results in PDFF error between small flip angle measurements and corrected large flip angle measurements as long as T1 estimates were within one standard deviation from the true value. Compared to low flip angle measurements, phantom and in vivo measurements demonstrate better precision and accuracy in PDFF measurements if images were acquired at a high flip angle, with T1 bias corrected using T1 estimates and flip angle mapping.

CONCLUSION

T1 bias correction of large flip angle acquisitions using estimated T1 values with flip angle mapping yields fat fraction measurements of similar accuracy and superior precision compared to low flip angle acquisitions.

Diffuse pattern of bone marrow involvement on magnetic resonance imaging is associated with high risk cytogenetics and poor outcome in newly diagnosed, symptomatic patients with multiple myeloma: a single center experience on 228 patients

Magnetic Resonance Imaging (MRI) and specific cytogenetic abnormalities offer important prognostic information for myeloma patients. However, limited data are available about the association between cytogenetic abnormalities and MRI patterns of marrow infiltration. To address this issue, we analyzed 228 consecutive newly diagnosed, symptomatic patients who were diagnosed and treated in a single center. On bone marrow MR images, 95 (41%) patients had diffuse, 94 (41%) had focal, 35 (15%) were normal, and 4 (1.7%) patients had variegated pattern of marrow infiltration. High risk cytogenetics were more commonly observed with diffuse MRI pattern (50% vs. 31% in focal and normal patterns). Patients with diffuse MRI pattern had poorer survival compared to others and responded better to novel agent-based therapies than to conventional chemotherapy (objective response: 88% vs. 46%, P < 0.001). There was a significant improvement of patients' survival with a diffuse MRI pattern when treated upfront with novel agents compared to conventional chemotherapy (47 vs. 24 months; P < 0.001). Diffuse MRI pattern along with ISS-3 and high risk cytogenetics could identify a very high risk group of patients with extremely poor median survival (21 months) and an only 35% probability of 3-year OS. Our study shows that symptomatic myeloma patients with a diffuse MRI pattern at diagnosis very often show high risk cytogenetic abnormalities and are benefiting from upfront novel agent-based therapies. Diffuse MRI pattern in combination with high risk cytogenetics and ISS-3 can identify a subset of myeloma patients with very poor prognosis who may need innovative treatment strategies and possibly more aggressive therapies.

The role of imaging techniques in the management of multiple myeloma

Bone disease is the major feature of multiple myeloma (MM). Imaging is required for correct staging, in the follow-up after treatment and, as recently highlighted, is predictor of prognosis. In the near future, whole-body X-Ray may be replaced by more sensitive techniques, such as whole-body low-dose computerized tomography (CT). Magnetic resonance imaging (MRI) is the gold standard method for assessing bone marrow infiltration of the spine, predicting the risk of vertebral fracture and distinguishing between benign and malignant osteoporosis. Positron emission tomography (PET) with CT (PET/CT) provides important information about the extent of whole-body disease, including soft tissue masses, and is the best tool to distinguish between active or inactive disease after therapy. Both MRI and PET/CT are predictors of clinical outcome. A prospective use of these newer imaging techniques in both clinical trials and clinical practice may help optimize MM management in the near future.

Quantitative MRI analysis of craniofacial bone marrow in patients with sickle cell disease

BACKGROUND AND PURPOSE

Assessment of bone marrow is most commonly performed qualitatively in the spine or other large long bones. The craniofacial bones are less ideal for bone marrow analysis because of the relatively small bone marrow volume. Because patients with SCD often undergo repeated brain imaging to evaluate for cerebral vaso-occlusive disease, quantitative assessment of craniofacial bone marrow is a reasonable possibility in these patients. The purpose of this study was to investigate specific sickle cell disease changes in craniofacial bone marrow quantitatively by analyzing T1, T2, and secular-T2 relaxation times and volume with the use of quantitative MRI.

MATERIALS AND METHODS

Fourteen patients with SCD and 17 control subjects were imaged with the mixed TSE pulse sequence at 1.5T. The craniofacial bones were manually segmented by using 3D Slicer to generate bone marrow volumes and to provide T1, T2, and secular-T2 relaxation times.

RESULTS

All subjects exhibited a bimodal T1 histogram. In the SCD group, there was a decrease in amplitude in the first T1 peak and an increase in amplitude in the second T1 peak. The first T1 peak showed a significant increase in relaxation time compared with control subjects (P < .0001), whereas there was no significant difference in the second T1 peak. T2 and secular-T2 relaxation times were significantly shorter in the SCD group (T2, P < .0001; secular-T2, P < .0001). Increasing numbers of blood transfusions resulted in a decrease in T2 and secular-T2 times. Patients with SCD exhibited a larger bone marrow volume compared with control subjects, even after standardization.

CONCLUSIONS

Patients with SCD exhibited significant quantifiable changes in the craniofacial bone marrow because of failure of red-to-yellow marrow conversion and iron deposition that can be identified by qMRI relaxometry and volumetry. Both qMRI relaxometry and volumetry may be used as noninvasive tools for assessment of disease severity.

Unusual presentation of tuberculosis with multiple spinal deposits

We discuss the relevant imaging of an unusual case of disseminated tuberculosis presenting with multifocal spinal deposits.

Leukemia and lymphoma

Leukemia and lymphoma are the most common and third most common pediatric malignancies, respectively, and share cell lineages, but the clinical and imaging manifestations of these malignancies vary substantially. Along with providing pertinent details on classification, epidemiology, and treatment, this article reviews the current roles of imaging in the management of childhood leukemia and lymphoma, with attention to diagnosis, staging, risk stratification, therapy response assessment, and surveillance for disease relapse and adverse effects of therapy. Advances in functional imaging are also discussed to provide insights into future applications of imaging in the management of pediatric patients with leukemia and lymphoma.