Efficacy of fat quantification methods used in MRI to distinguish between normal, benign, and malignant bone marrow pathologies in children.

BACKGROUND: Fat quantification methods in magnetic resonance imaging (MRI) have been studied to differentiate bone marrow pathologies in adult patients; however, scarce literature is available in pediatric patients. PURPOSE: To evaluate the efficacy of the T1 signal intensity value (T1-SIV), out-of-phase/in-phase signal ratio (OP/IP SR), and fat fraction (FF) to differentiate between normal, benign, and malignant pathological processes. MATERIAL AND METHODS: A total of 48 pediatric patients with lumbar and pelvic MRI were classified into three groups according to bone marrow pathology (group 1, normal; group 2, benign pathology/reconversion; group 3, malignant). The efficacy of T1-SIV, OP/IP SR, and FF values in differentiating these pathologies was evaluated using Kruskal-Wallis or analysis of variance and followed by Bonferroni or Dunn-Bonferroni tests. Cutoff values for malignant infiltration were defined using ROC analysis. RESULTS: Although these values were significantly different in all three groups (P = 0.001-0.008), this difference was not sufficient to discriminate between all groups. Subgroup analyses showed significant differences in T1-SIV between groups 1-3, in OP/IP SR between groups 1-3, 2-3, and 1-2, in FF between groups 1-2 and 1-3 in various regions (P = 0.001-0.049). Cutoff values had a sensitivity and specificity of 90%-100% for OP/IP SR and FF. CONCLUSION: T1-SIV, OP/IP SR, and FF may potentially distinguish normal from pathological bone marrow. OP/IP SR and FF values detected malignant infiltration with high sensitivity and specificity in this study. However, only OP/IP SR may significantly differentiate benign and malignant bone marrow pathologies which needs to be confirmed in the future study with a larger patient population.

Bone marrow disease in rhabdomyosarcoma visualized by 2-[18F]fluorodeoxyglucose positron emission tomography/computed tomography.

Bone marrow metastases-noted in 6% of patients with rhabdomyosarcoma-have been linked to very poor outcomes. Bilateral bone marrow sampling from iliac crests has been the gold standard for bone marrow examination in rhabdomyosarcoma, but sampling errors due to patchy bone marrow involvement may limit its sensitivity. Here, we report the case of a 6-year-old boy with embryonal rhabdomyosarcoma of the skull base and multiple 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG)-avid bone marrow metastases visualized by positron emission tomography and computed tomography (2-[18F]FDG PET/CT). His bone marrow aspirates were tumor-free. This case illustrates the diagnostic value of 2-[18F]FDG PET/CT in the detection of bone marrow metastases in rhabdomyosarcoma patients, which may re-shape the definition of bone marrow disease and, ultimately, alter disease staging and risk stratification.

Whole-body three-dimensional short tau inversion recovery and T1-weighted in/opposed phase MRI in the detection of neuroblastoma bone marrow metastasis: comparative study with PET/CT utilising bone marrow biopsy as the reference standard.

AIM: To evaluate the diagnostic accuracy of whole-body (WB) magnetic resonance imaging (MRI) utilising three-dimensional (3D) short tau inversion recovery (STIR) and T1-weighted in/opposed-phase MRI in the detection of neuroblastoma bone marrow metastasis compared to 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT). MATERIALS AND METHODS: A prospective study of 20 consecutive histopathologically proven neuroblastoma patients enrolled in this study from January 2021 to August 2022. WB MRI and FDG-PET/CT were performed for all cases. Bone marrow biopsy served as the standard of reference. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy were calculated. In addition, lesion-by-lesion analysis was performed and the number of bone marrow metastatic lesions in different body segments using both imaging methods was recorded and compared. RESULTS: WB MRI correctly identified true positives and true negatives in all cases with a sensitivity and specificity of 100%. In contrast, FDG-PET/CT showed two false-negative cases that resulted in a sensitivity, specificity, PPV, NPV, and accuracy of 86.7%, 100%, 100%, 71.4%, and 92%, respectively. In the lesion-by-lesion analysis, WB MRI detected more (24.3%) bone marrow metastatic lesions than FDG-PET/CT. CONCLUSION: Whole-body MRI can reliably identify neuroblastoma bone marrow infiltration, and could be an alternative to PET/CT in that regard.

Detection of bone marrow metastases in children and young adults with solid cancers with diffusion-weighted MRI.

OBJECTIVE: To compare the diagnostic accuracy of diffusion-weighted (DW)-MRI with b-values of 50 s/mm2 and 800 s/mm2 for the detection of bone marrow metastases in children and young adults with solid malignancies. METHODS: In an institutional review board-approved prospective study, we performed 51 whole-body DW-MRI scans in 19 children and young adults (14 males, 5 females; age range: 1-25 years) with metastasized cancers before (n = 19 scans) and after (n = 32 scans) chemotherapy. Two readers determined the presence of focal bone marrow lesions in 10 anatomical areas. A third reader measured ADC and SNR of focal lesions and normal marrow. Simultaneously acquired 18F-FDG-PET scans served as the standard of reference. Data of b = 50 s/mm2 and 800 s/mm2 images were compared with the Wilcoxon signed-rank test. Inter-reader agreement was evaluated with weighted kappa statistics. RESULTS: The SNR of bone marrow metastases was significantly higher compared to normal bone marrow on b = 50 s/mm2 (mean ± SD: 978.436 ± 1239.436 vs. 108.881 ± 109.813, p < 0.001) and b = 800 s/mm2 DW-MRI (499.638 ± 612.721 vs. 86.280 ± 89.120; p < 0.001). On 30 out of 32 post-treatment DW-MRI scans, reconverted marrow demonstrated low signal with low ADC values (0.385 × 10-3 ± 0.168 × 10-3mm2/s). The same number of metastases (556/588; 94.6%; p > 0.99) was detected on b = 50 s/mm2 and 800 s/mm2 images. However, both normal marrow and metastases exhibited low signals on ADC maps, limiting the ability to delineate metastases. The inter-reader agreement was substantial, with a weighted kappa of 0.783 and 0.778, respectively. CONCLUSION: Bone marrow metastases in children and young adults can be equally well detected on b = 50 s/mm2 and 800 s/mm2 images, but ADC values can be misleading.

Diagnostic Accuracy of 2-[18F]FDG-PET and whole-body DW-MRI for the detection of bone marrow metastases in children and young adults.

OBJECTIVES: To compare the diagnostic accuracy of 2-[18F]fluoro-2-deoxy-D-glucose-enhanced positron emission tomography (2-[18F]FDG-PET) and diffusion-weighted magnetic resonance imaging (DW-MRI) for the detection of bone marrow metastases in children and young adults with solid malignancies. METHODS: In this cross-sectional single-center institutional review board-approved study, we investigated twenty-three children and young adults (mean age, 16.8 years ± 5.1 [standard deviation]; age range, 7-25 years; 16 males, 7 females) with 925 bone marrow metastases who underwent 66 simultaneous 2-[18F]FDG-PET and DW-MRI scans including 23 baseline scans and 43 follow-up scans after chemotherapy between May 2015 and July 2020. Four reviewers evaluated all foci of bone marrow metastasis on 2-[18F]FDG-PET and DW-MRI to assess concordance and measured the tumor-to-bone marrow contrast. Results were assessed with a one-sample Wilcoxon test and generalized estimation equation. Bone marrow biopsies and follow-up imaging served as the standard of reference. RESULTS: The reviewers detected 884 (884/925, 95.5%) bone marrow metastases on 2-[18F]FDG-PET and 893 (893/925, 96.5%) bone marrow metastases on DW-MRI. We found different "blind spots" for 2-[18F]FDG-PET and MRI: 2-[18F]FDG-PET missed subcentimeter lesions while DW-MRI missed lesions in small bones. Sensitivity and specificity were 91.0% and 100% for 18F-FDG-PET, 89.1% and 100.0% for DW-MRI, and 100.0% and 100.0% for combined modalities, respectively. The diagnostic accuracy of combined 2-[18F]FDG-PET/MRI (100.0%) was significantly higher compared to either 2-[18F]FDG-PET (96.9%, p < 0.001) or DW-MRI (96.3%, p < 0.001). CONCLUSIONS: Both 2-[18F]FDG-PET and DW-MRI can miss bone marrow metastases. The combination of both imaging techniques detected significantly more lesions than either technique alone. KEY POINTS: • DW-MRI and 2-[18F]FDG-PET have different strengths and limitations for the detection of bone marrow metastases in children and young adults with solid tumors. • Both modalities can miss bone marrow metastases, although the "blind spot" of each modality is different. • A combined PET/MR imaging approach will achieve maximum sensitivity and specificity for the detection of bone marrow metastases in children with solid tumors.

Diagnostic Accuracy and Prognostic Relevance of Immunoglobulin Heavy Chain Rearrangement and 18F-FDG-PET/CT Compared With Unilateral Bone Marrow Trephination for Detecting Bone Marrow Involvement in Patients With Diffuse Large B-Cell Lymphoma.

BACKGROUND: In diffuse large B-cell lymphoma (DLBCL), bone marrow involvement (BMI) has an important clinical implication as a component of staging and International Prognostic Index. This study aimed to determine whether molecular analysis of immunoglobulin heavy chain (IgH) genes and positron emission tomography-computed tomography (PET/CT) could overcome the limitation of defining morphologic BMI by trephination biopsy and could increase the diagnostic accuracy or prognostic prediction. METHODS: A total of 94 de novo patients with DLBCL underwent PET/CT, polymerase chain reaction (PCR) test for detection of IgH gene rearrangement, and unilateral bone marrow (BM) trephination at diagnosis. RESULTS: A total of 9 patients (9.6%) were confirmed to present morphologic BMI (mBMI) based on trephination biopsy. On the other hand, 21 patients (22.3%) were confirmed to have IgH clonality (IgH BMI), while 16 (17.0%) were classified with BMI based on the assessment of PET/CT (PET BMI). Each IgH rearrangement PCR and PET/CT showed the high negative predictive value of detecting the BMI. However, the combined assessment of IgH rearrangement and PET/CT could increase the diagnostic accuracy and specificity with 87.2% and 97.0%, respectively. The survival outcome of patients with double positive PET BMI and IgH BMI was significantly worse than that with either single positive PET BMI or IgH BMI, and even less than patients with neither PET BMI nor IgH BMI (3-year PFS: 50.0% vs. 75.4% vs. 97.9%, P = 0.007, 3-year OS: 50.0% vs. 75.6% vs. 80.1%, P = 0.035, respectively). CONCLUSION: This study suggests that the combined evaluation of PET/CT and IgH rearrangement could give additional information for predicting therapeutic outcomes in patients with negative morphologic BMI as an important part of the prognosis.

Magnetic resonance imaging for assessing treatment response in bone marrow metastases.

Cancer metastasis to bone is a frequent observation in malignancy that may result in complications such as pathological fractures and spinal cord compression. Monitoring treatment effects is the main concern in oncology; however, the evaluation of treatment response in bone is particularly challenging as it lacks well-established criteria. In addition, bone metastases have traditionally been considered non-measurable manifestations of cancer. Magnetic resonance imaging (MRI) is one of the most specific and sensitive methods for imaging skeletal metastases. The aim of this article is to highlight the diagnostic performance of MRI in the treatment monitoring of bone metastases, to review the current literature, and to provide an overview of recommendations for the evaluation of treatment response in bone.

Advanced MR imaging of bone marrow: quantification of signal alterations on T1-weighted Dixon and T2-weighted Dixon sequences in red marrow, yellow marrow, and pathologic marrow lesions.

OBJECTIVES: To quantify and compare signal intensity (SI) changes on T1-weighted (W) and T2W Dixon imaging in yellow marrow, red marrow, and bone marrow lesions. MATERIALS AND METHODS: A total of 141 patients (77 controls, 64 lesions-33 benign, 31 malignant) between January 2016 and December 2017 were retrospectively identified. For the control group, fixed 2-cm2 region of interests (ROI) were drawn at L5, bilateral ilium and femurs on in-phase and opposed-phase T1W and T2W Dixon images. For the lesion group, ROIs of best fit were drawn around each lesion on in-phase and opposed-phase T2W Dixon images. SI changes between in-phase and opposed phase maps for each group were compared. Inter-reader analysis was performed. RESULTS: Yellow marrow exhibited smaller SI changes as compared to red marrow on both T1W and T2W Dixon imaging at all locations (p < 0.0001) except at L5 on T2W Dixon imaging (p = 0.206). Both benign and malignant lesions showed significantly smaller SI changes as compared to both yellow (p = 0.0087, p < 0.0001) and red marrow (p = 0.0004, p < 0.0001) on T2W Dixon imaging. Malignant lesions exhibited smaller SI change as compared to benign lesions on T2W Dixon imaging (p = 0.0005). Signal intensity loss on both red and yellow marrow were smaller on T1W Dixon as compared to T2W Dixon (0.49-0.64, 0.27-0.31 vs. 0.70-0.74, 0.48-0.71). Inter-reader agreements were excellent (0.91-0.97). CONCLUSIONS: SI change calculated from T2-weighted Dixon imaging can adequately differentiate between yellow marrow, red marrow, and osseous lesions, both benign and malignant.

Bone marrow biopsy in the initial staging of Ewing sarcoma: Experience from a single institution.

BACKGROUND: Ewing sarcoma (ES) is the second most common bone tumor in adolescents and children. Staging workup for ES includes imaging and bone marrow biopsy (BMB). The effective role of BMB is now under discussion. PROCEDURE: A monoinstitutional retrospective analysis reviewed clinical charts, imaging, and histology of patients with diagnosis of ES treated at the Rizzoli Institute between 1998 and 2017. RESULTS: The cohort included 504 cases of ES of bone; 137 (27%) had metastases at diagnosis, while the remaining 367 had localized disease. Twelve patients had a positive BMB (2.4%). Eleven had distant metastases detected at initial workup staging with imaging assessment: six patients presented with bone metastases, five with both bone and lung metastases. Only one patient with ES of the foot (second metatarsus) was found to have bone marrow involvement with negative imaging evaluation (0.3%). CONCLUSIONS: On the basis of our data, we suggest reconsidering the effective role of BMB in initial staging workup for patients with ES with no signs of metastases by modern imaging techniques. In metastatic disease, the assessment of the bone marrow status may remain useful to identify a group of patients at very high risk who could benefit from different treatment strategies.

Detection of Lumbar Spine Osseous Metastases Using Dual-Energy CT: Phantom Results and Preliminary Clinical Validation.

OBJECTIVE: The purpose of this study was to evaluate the sensitivity, tumor conspicuity, and image quality of different material decomposition images of phantoms and patients with nearly isodense bone metastases using rapid-kilovoltage-switching dual-energy CT (DECT). MATERIALS AND METHODS: Fifty-one semianthropomorphic lumbar spine phantoms embedded with 75 simulated tumors were scanned without and with outer torso-attenuating encasement under the same scan settings. Two radiologists independently reviewed the 70-keV virtual monochromatic and material decomposition images (hydroxyapatite-water, water-hydroxyapatite, cortical bone-water, water-cortical bone). The sensitivity of tumor detection, tumor conspicuity (on a 3-point scale), and image quality (on a 3-point scale) were recorded by two independent readers. McNemar and Wilcoxon signed rank tests were used to compare results between the image reconstructions. Six clinical abdominopelvic DECT scans (three men, three women; mean age, 52 years) with nine nearly isodense lumbar spine tumors missed in the clinical report but confirmed on other scans were also evaluated. RESULTS: The hydroxyapatite-water material decomposition algorithm showed improved sensitivity for isodense lesion detection (without torso phantom encasement, 94% vs 82%, p = 0.031; with torso phantom encasement, 38% vs 18%, p = 0.013), and higher tumor conspicuity scores (p < 0.0001) compared with 70-keV virtual monoenergetic images. Artifacts were more prevalent with all material decomposition images than with 70-keV virtual monoenergetic images. Similar results were seen in the patient study. CONCLUSION: Dual-energy CT with hydroxyapatite-water material decomposition may improve the detection of bone marrow metastases, especially for subtle isodense tumors. Further study in prospective clinical scans is warranted.

The Value of 18F-FDG PET/CT in Detecting Bone Marrow Involvement in Childhood Cancers.

BACKGROUND: The aim of this study was to assess the utility of F-fluoro-2-deoxy-D-glucose (F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing bone marrow involvement (BMI) compared with bone marrow biopsy (BMB) in the initial staging of pediatric patients with non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL), Ewing sarcoma (ES), and neuroblastoma (NB). PROCEDURE: A total of 94 patients (57 boys, 37 girls, median age 7 y, range 1 to 18 y) with newly diagnosed NHL, HL, ES, and NB between July 2014 and December 2017, who underwent BMB and F-FDG PET/CT before chemotherapy were included in this study. There were 36 patients with NHL, 27 HL, 16 ES, and 15 NB. F-FDG PET/CT and BMB results were reviewed and compared retrospectively. FINDINGS: Retrospective analysis of data from 94 pediatric patients (57 boys, 37 girls, median age 7 y, range 1 to 18 y) was performed. Of the 94 patients, 29 had BMI on F-FDG PET/CT. BMB was positive in 14, negative in 13, and insufficient in 2 of these 29 patients. In 65 patients negative on F-FDG PET/CT, BMB was also negative in 54 and insufficient in 7. For the whole group, sensitivity, specificity, and positive and negative predictive values of F-FDG PET/CT in detecting bone marrow metastasis at the time of diagnosis were 90.6%, 100%, 100%, and 95.4% and those of BMB were 53.1%, 87.1%, 94.4%, and 80.6%, respectively. CONCLUSION: Our study demonstrates that F-FDG PET/CT predicts BMI better than BMB. F-FDG PET/CT may be used at initial staging of pediatric patients with NHL, HL, ES, and NB.

Neuroblastoma of the Bone and Bone Marrow Without an Apparent Primary Site: Report of 4 Cases With Long-term Follow-up.

Children with neuroblastoma rarely present with metastatic disease without identifiable primary tumors. We describe the clinical and histopathologic characteristics of 4 patients aged 1, 7, 7, and 11 years with neuroblastoma involving bone or bone marrow without an apparent primary site. One patient presented with a periorbital bone lesion, 1 presented with a distal femoral lesion, and 2 presented with diffuse bone marrow involvement. All tumors were negative for MYCN amplification. All patients were alive without evidence of disease 5 years after completion of multimodality therapy. Patients with neuroblastoma of the bone and bone marrow without an apparent primary site may constitute a unique group characterized by older age at diagnosis, nonamplified MYCN tumors, and good response to treatment.

Myeloproliferative Neoplasms: A Primer for Radiologists.

The myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases including polycythemia vera, essential thrombocythemia, and primary myelofibrosis. Knowledge of the radiological and clinical features of MPNs and their associated complications is critical for interpreting radiologists. The purpose of this article is to provide a primer to radiologists summarizing the modern understanding of MPNs from an imaging-based perspective, including common disease-related findings and complications related to hematopoietic cell transplant.

The new international neuroblastoma response criteria.

Over recent years significant advances in histopathology and functional imaging techniques for the diagnosis and restaging of children with neuroblastoma have led to better quantification of disease and assessment of disease response, allowing for better treatment stratification. In this review we summarise recent changes to the International Neuroblastoma Response Criteria including the use of RECIST (Response Evaluation Criteria in Solid Tumours) guidance for measurable soft-tissue disease, replacement of technetium-99 m-methylene diphosphonate (MDP) bone scans with metaiodobenzylguanidine (MIBG) scan or [F-18]2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET)/CT scanning, and a new category of minimal residual bone marrow disease.

Anaplastic oligodendroglioma metastasizing to the bone marrow: a unique case report and literature review.

Oligodendrogliomas are a rare type of primary brain tumor. They are genetically defined as diffuse gliomas carrying mutation in isocitrate dehydrogenase type 1 (IDH1) or type 2 (IDH2) and codeletion of chromosomes 1p and 19q. The WHO grading system distinguishes two histopathologic grades of ODs: grade II (low-grade) and grade III (anaplastic oligodendroglioma or AO). These tumors rarely metastasize outside of central nervous system with only few cases reported in the literature. Here we present a case of an AO, which metastasized to the bone marrow and other sites within a year of diagnosis despite aggressive treatment measures. Our patient eventually succumbed to his disease, raising many questions about this rare condition, its natural course and optimal management strategy.

Efficacy of chemical shift MRI for differentiating diffuse red bone marrow reconversion and hematological malignancies

Background/aim: The main purpose of our study was to determine the efficacy of chemical shift imaging (CSI) for differentiating diffuse red bone marrow reconversion (RBMR) and hematological malignancies. We also aimed to calculate the cut-off value for these entities with similar imaging features in routine magnetic resonance (MR) sequences. Materials and methods: A total of 54 patients were included: 17 patients (31.4%) with hematological malignancies (group 1), 16 patients (29.6%) with RBMR (group 2), and 21 patients (38.0%) with no clinical and hematological malignancies (control group). Patients with no pathological data or completed two-year follow-up and children were excluded from the study. An experienced radiologist on MRI evaluated the images blindly for final diagnosis. Pathologic results were determined as gold standard. Regions of interests (ROI) were placed on the vertebrae in CSI and signal intensity ratios (SIR) were calculated. The cut-off value was calculated using receiver operating characteristic (ROC) analysis. Results: SIR values were 0.97 ± 0.16, 0.69 ± 0.31 and 0.28 ± 0.35 (P < 0.001) for GI, G2, and G3, respectively. The cut-off value was 0.82 (P < 0.001). The sensitivity rate was 83.3% (AUC: 58%­96%), specificity was 87% (AUC: 58­98). Conclusion: CSI may be a valuable diagnostic tool for differentiating diffuse RBMR and hematological malignancies.

Bone Marrow Metastases: T2-weighted Dixon Spin-Echo Fat Images Can Replace T1-weighted Spin-Echo Images.

Purpose To test the potential of Dixon T2-weighted fat-only sequences to replace T1-weighted sequences for the detection of bone metastases, with the hypothesis that diagnostic performance with an alternative magnetic resonance (MR) imaging protocol (sagittal spin-echo Dixon T2-weighted fat-only and water-only imaging) would not be inferior to that with the standard protocol (sagittal spin-echo T1-weighted and spin-echo Dixon T2-weighted water-only imaging). Materials and Methods A total of 121 consecutive whole-spine MR imaging examinations (63 men; mean age ± standard deviation, 61.4 years ± 11.8) performed for suspected vertebral bone metastases were included in this retrospective, institutional review board-approved study. Quantitative image analysis was performed for 30 randomly selected spine levels. Qualitative analysis was performed separately by two musculoskeletal radiologists, who registered the number of metastases for each spine level. Areas under the curve with the protocols were compared on the basis of nonparametric receiver operating characteristic curve estimations by using a noninferiority test on paired data, with a best valuable comparator as a reference. Interobserver and interprotocol agreement was assessed by using κ statistics. Results Contrast-to-noise ratio was significantly higher on the alternative protocol images than on the standard protocol images (181.1 [95% confidence interval: 140.4, 221.7] vs 84.7 [95% confidence interval: 66.3, 103.1] respectively; P < .001). Diagnostic performance was not significantly inferior with the alternative protocol than with the standard protocol for both readers in a per-patient analysis (sensitivity, 97.9%-98.9% vs 93.6%-97.9%; specificity, 85.2%-92.6% vs 92.6%-96.3%; area under the curve, 0.92-0.96 vs 0.95, respectively; all P ≤ .02) and a per-spine level analysis (all P < .01). Interobserver and interprotocol agreement was good to very good (κ = 0.70-0.81). Conclusion Dixon T2-weighted fat-only and water-only imaging provide, in one sequence, diagnostic performance similar to that of the standard combination of morphologic sequences for the detection of probable spinal bone metastases, thereby providing an opportunity to reduce imaging time by eliminating the need to perform T1 sequences. © RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on November 6, 2017.

PET/CT predicts bone marrow involvement in paediatric non-Hodgkin lymphoma and may preclude the need for bone marrow biopsy in selected patients.

OBJECTIVES: To investigate the role of 18F-FDG PET/CT to detect bone marrow (BM) involvement in paediatric non-Hodgkin lymphoma (NHL). METHODS: Pretreatment PET/CT scans from 93 consecutive paediatric patients with NHL were retrospectively reviewed. Patterns of BM FDG uptake and standardized uptake value of the fifth lumbar vertebra (SUVBM) were compared with bone marrow biopsy (BMB) for diagnosis of BM involvement. RESULTS: Of 93 patients, 41 were judged to have BM involvement. Thirty-nine were identified by PET/CT, versus 23 by BMB. Sensitivity and specificity were 95 % and 98 % for PET/CT and 56 % and 100 % for BMB, respectively. None of the patients with BM FDG uptake lower than liver had positive BMB. In 45 patients presenting homogeneously increased BM uptake, positive BMB was achieved in 93 % (14/15) of patients with FDG uptake expanding to the distal portion of extremities, compared to 7 % (2/30) of those without. A multifocal pattern was observed in 25 patients and 18 had negative BMB. SUVBM differentiated BM involvement from benign BM activation with an area under the curve of 0.885 (p < 0.001). CONCLUSIONS: PET/CT had a high level of accuracy for detecting BM involvement in paediatric NHL. BMB might be omitted in selected patients. KEY POINTS: • PET/CT allows for accurate detection of bone marrow involvement. • Patterns of bone marrow FDG uptake are highly correlated with marrow disease. • Bone marrow biopsy could be omitted in selected paediatric patients.

The Ability of Dual-Energy Computed Tomography to Distinguish Normal Bone Marrow From Metastases Using Bone Marrow Color Maps.

OBJECTIVE: The objective of this study was to determine if dual-energy computed-tomography bone marrow color maps can improve sensitivity, specificity, accuracy, and confidence of detection of bone metastases. METHODS: Institutional review board approved this retrospective review of a consecutive series of cancer patients. Two radiologists first evaluated the fused 120 kV computed tomography images and recorded a number of suspicious lesions, confidence level, and Hounsfield units for each lesion. After a time gap, the studies were randomized for a second review with dual-energy computed-tomography bone marrow color maps. RESULTS: Eighteen patients and 1105 bones were reviewed. A total of 227 true metastatic lesions were present. With bone marrow color map review, sensitivity increased from 76.2% to 86.8%, for reader 1, and from 80.2% to 92.8%, for reader 2. Specificity and accuracy also increased. Confidence level increased for 12 lesions. CONCLUSIONS: Dual-energy computed-tomography bone marrow color map analysis of patients with metastatic cancers can improve the sensitivity, specificity, accuracy, and confidence level for the detection of bone metastases.

Usefulness of positron emission tomography-CT for diagnosis of primary bone marrow lymphoma in children.

Primary bone marrow lymphoma (PBML) is hard to diagnose in children, due to the difficult identification of malignant cells in bone marrow. The first case, a 5-year-old boy, showed knee swelling with an intermittent fever. The second case, a 12-year-old girl, showed fever of unknown origin without lymphadenopathy or hepatosplenomegaly. In both cases, the diagnosis was not confirmed despite the repeated bone marrow aspirations. Finally, bone marrow aspiration and biopsy at the positive site by positron emission tomography (PET)-CT contributed to definitive diagnosis of PBML. The PET-CT is useful for the accurate diagnosis of PBML in children with non-specific symptoms.