Apparent diffusion coefficient of vertebral haemangiomas allows differentiation from malignant focal deposits in whole-body diffusion-weighted MRI

Vertebral hemangiomas: a review on diagnosis and management

BACKGROUND

Vertebral hemangiomas (VHs) are the most common benign tumors of the spinal column and are often encountered incidentally during routine spinal imaging.

METHODS

A retrospective review of the inpatient and outpatient hospital records at our institution was performed for the diagnosis of VHs from January 2005 to September 2023. Search filters included "vertebral hemangioma," "back pain," "weakness," "radiculopathy," and "focal neurological deficits." Radiographic evaluation of these patients included plain X-rays, CT, and MRI. Following confirmation of a diagnosis of VH, these images were used to generate the figures used in this manuscript. Moreover, an extensive literature search was conducted using PubMed for the literature review portion of the manuscript.

RESULT

VHs are benign vascular proliferations that cause remodeling of bony trabeculae in the vertebral body of the spinal column. Horizontal trabeculae deteriorate leading to thickening of vertical trabeculae which causes a striated appearance on sagittal magnetic resonance imaging (MRI) and computed tomography (CT), "Corduroy sign," and a punctuated appearance on axial imaging, "Polka dot sign." These findings are seen in "typical vertebral hemangiomas" due to a low vascular-to-fat ratio of the lesion. Contrarily, atypical vertebral hemangiomas may or may not demonstrate the "Corduroy" or "Polka-dot" signs due to lower amounts of fat and a higher vascular component. Atypical vertebral hemangiomas often mimic other neoplastic pathologies, making diagnosis challenging. Although most VHs are asymptomatic, aggressive vertebral hemangiomas can present with neurologic sequelae such as myelopathy and radiculopathy due to nerve root and/or spinal cord compression. Asymptomatic vertebral hemangiomas do not require therapy, and there are many treatment options for vertebral hemangiomas causing pain, radiculopathy, and/or myelopathy. Surgery (corpectomy, laminectomy), percutaneous techniques (vertebroplasty, sclerotherapy, embolization), and radiotherapy can be used in combination or isolation as appropriate. Specific treatment options depend on the lesion's size/location and the extent of neural element compression. There is no consensus on the optimal treatment plan for symptomatic vertebral hemangioma patients, although management algorithms have been proposed.

CONCLUSION

While typical vertebral hemangioma diagnosis is relatively straightforward, the differential diagnosis is broad for atypical and aggressive lesions. There is an ongoing debate as to the best approach for managing symptomatic cases, however, surgical resection is often considered first line treatment for patients with neurologic deficit.

Surgical management of symptomatic vertebral hemangiomas: a single institution experience and literature review

Vertebral hemangiomas (VHs), formed from a vascular proliferation in bone marrow spaces limited by bone trabeculae, are the most common benign tumors of the spine. While most VHs remain clinically quiescent and often only require surveillance, rarely they may cause symptoms. They may exhibit active behaviors, including rapid proliferation, extending beyond the vertebral body, and invading the paravertebral and/or epidural space with possible compression of the spinal cord and/or nerve roots ("aggressive" VHs). An extensive list of treatment modalities is currently available, but the role of techniques such as embolization, radiotherapy, and vertebroplasty as adjuvants to surgery has not yet been elucidated. There exists a need to succinctly summarize the treatments and associated outcomes to guide VH treatment plans. In this review article, a single institution's experience in the management of symptomatic VHs is summarized along with a review of the available literature on their clinical presentation and management options, followed by a proposal of a management algorithm.

Diagnostic value of WB-DWI versus 18F-FDG PET/CT for the detection of multiple myeloma

Background

Whole-body diffusion-weighted imaging (WB-DWI) is commonly used for the detection of multiple myeloma (MM). Comparative data on the efficiency of WB-DWI compared with F-18 fluoro-2-deoxy-d-glucose positron emission tomography-computed tomography (18F-FDG PET/CT) to detect MM is limited.

Methods

This was a retrospective, single-center study of 22 patients with MM enrolled from January 2018 to December 2019. All patients underwent WB-DWI and 18F-FDG PET/CT. Pathological and clinical manifestations, as well as radiologic follow-up, were used for diagnosis. The overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of both methods were compared. The apparent diffusion coefficient (ADC) values of MM lesions and false-positive lesions were estimated.

Results

A total of 214 MM bone lesions were evaluated. There was no significant difference in the accuracy of WB-DWI and PET/CT (86.92 versus 88.32%). Though WB-DWI had a higher sensitivity (99.26% versus84.56%) and PET-CT had a higher specificity (96.10% versus 64.56%), these differences were not statistically significant. There was a statistically significant difference in PPV (83.33% versus 96.64%) and NPV (98.08% versus 77.89%) of WB-DWI and PET/CT, respectively. The ADC value for MM lesions was significantly lower than that for false-positive lesions (P < 0.001). Receiver operating curve analysis showed that the AUC was 0.846, and when the cut-off value was 0.745 × 10-3 mm2/s, the sensitivity and specificity were 86.3 and 83.4%, respectively, which distinguished MM lesions from non-MM lesions.

Conclusion

WB-DWI and PET-CT scans have similar overall accuracy for detecting MM lesions. The higher PPV of PET-CT and NPV of WB-DWI make them complementary imaging modalities. The ADC value for MM lesions is significantly lower than that for false-positive lesions. An ADC cutoff value of 0.745 × 10-3 mm2/s results in sensitivity and specificity of 86.3 and 83.4%, respectively.

Pitfalls of Diffusion-Weighted Imaging: Clinical Utility of T2 Shine-through and T2 Black-out for Musculoskeletal Diseases

Diffusion-weighted imaging (DWI) with an apparent diffusion coefficient (ADC) value is a relatively new magnetic resonance imaging (MRI) sequence that provides functional information on the lesion by measuring the microscopic movement of water molecules. While numerous studies have evaluated the promising role of DWI in musculoskeletal radiology, most have focused on tumorous diseases related to cellularity. This review article aims to summarize DWI-acquisition techniques, considering pitfalls such as T2 shine-through and T2 black-out, and their usefulness in interpreting musculoskeletal diseases with imaging. DWI is based on the Brownian motion of water molecules within the tissue, achieved by applying diffusion-sensitizing gradients. Regardless of the cellularity of the lesion, several pitfalls must be considered when interpreting DWI with ADC values in musculoskeletal radiology. This review discusses the application of DWI in musculoskeletal diseases, including tumor and tumor mimickers, as well as non-tumorous diseases, with a focus on lesions demonstrating T2 shine-through and T2 black-out effects. Understanding these pitfalls of DWI can provide clinically useful information, increase diagnostic accuracy, and improve patient management when added to conventional MRI in musculoskeletal diseases.

Diffusion-weighted imaging (DWI) in diagnosis, staging, and treatment response assessment of multiple myeloma: a systematic review and meta-analysis

OBJECTIVE

To evaluate the role of diffusion-weighted imaging (DWI) in the initial diagnosis, staging, and assessment of treatment response in patients with multiple myeloma (MM).

MATERIALS AND METHODS

A systematic literature review was conducted in PubMed, the Cochrane Library, EMBASE, Scopus, and Web of Science databases. The primary endpoints were defined as the diagnostic performance of DWI for disease detection, staging of MM, and assessing response to treatment in these patients.

RESULTS

Of 5881 initially reviewed publications, 33 were included in the final qualitative and quantitative meta-analysis. The diagnostic performance of DWI in the detection of patients with MM revealed pooled sensitivity and specificity of 86% (95% CI: 84-89) and 63% (95% CI: 56-70), respectively, with a diagnostic odds ratio (OR) of 14.98 (95% CI: 4.24-52.91). The pooled risk difference of 0.19 (95% CI: - 0.04-0.42) was reported in favor of upstaging with DWI compared to conventional MRI (P value = 0.1). Treatment response evaluation and ADC_mean value changes across different studies showed sensitivity and specificity of approximately 78% (95% CI: 72-83) and 73% (95% CI: 61-83), respectively, with a diagnostic OR of 7.21 in distinguishing responders from non-responders.

CONCLUSIONS

DWI is not only a promising tool for the diagnosis of MM, but it is also useful in the initial staging and re-staging of the disease and treatment response assessment. This can aid clinicians with earlier initiation or change in treatment strategy, which could have prognostic significance for patients.

Vertebral Hemangiomas: Prevalence, new classification and natural history. magnetic resonance imaging-based retrospective longitudinal study

BACKGROUND AND PURPOSE

To determine the prevalence of vertebral hemangiomas (VHs), establish a new classification of VHs based on their MRI-signal pattern, and study their natural history.

METHODS

MRI of 1000 consecutive patients who underwent at least two MRI with an interval of at least 3 years. Growth rate and change of MRI-signal pattern during the follow-up period were the parameters included in studying the natural history of VHs.

RESULTS

The prevalence of VHs was 41%. VHs were classified as type I-IV with fat-rich VHs (type I), constituted 79% of all VHs. VHs were more common among females 43% versus males 39%, p = .22. The most affected vertebra was L1. Occurrence rates for cervical (1%), thoracic (7%), and lumbar spine (10%) differed significantly (p < .001). The prevalence of VHs increased with age regardless of gender or spinal part involved (p < .001). Only 26% of VHs changed their size and 4% changed their signal during the average follow-up of 7 years. All VHs were slowly growing lesions (average expected growth of <3 mm/10 years). No significant difference between growth rate of VHs type I (0.25 mm/year) and other types of VHs. None of the VHs that were initially reported as "metastases cannot be rule out" showed alarming change in signal or size.

CONCLUSIONS

VH can be classified into four types based on their MRI-signal pattern. Regardless of their type, VHs are slowly growing lesions. The presence of typical morphological pattern should enable radiologists to confidently differentiate them from vertebral metastases.

[Clinical Application and Limitations of Myeloma Response Assessment and Diagnosis System (MY-RADS)]

Multiple myeloma, which is a proliferative disease of plasma cells that originate from a single clone, is the second most common hematologic malignancy following non-Hodgkin lymphoma. In the past, its diagnosis was made based on clinical findings (so-called "CRAB") and a skeletal survey using radiographs. However, since the implementation of the International Myeloma Working Group's revised guideline regarding the radiologic diagnosis of multiple myeloma, whole-body (WB) MRI has emerged to play a central role in the early diagnosis of multiple myeloma. Diffusion-weighted imaging and fat quantification using Dixon methods enable treatment response assessment by MRI. In keeping with the trend, a multi-institutional and multidisciplinary consensus for standardized image acquisition and reporting known as the Myeloma Response Assessment and Diagnostic System (MY-RADS) has recently been proposed. This review aims to describe the clinical application of WB-MRI based on MY-RADS in multiple myeloma, discuss its limitations, and suggest future directions for improvement.

Review of diffusion-weighted imaging and dynamic contrast-enhanced MRI for multiple myeloma and its precursors (monoclonal gammopathy of undetermined significance and smouldering myeloma)

The last decades, increasing research has been conducted on dynamic contrast-enhanced and diffusion-weighted MRI techniques in multiple myeloma and its precursors. Apart from anatomical sequences which are prone to interpretation errors due to anatomical variants, other pathologies and subjective evaluation of signal intensities, dynamic contrast-enhanced and diffusion-weighted MRI provide additional information on microenvironmental changes in bone marrow and are helpful in the diagnosis, staging and follow-up of plasma cell dyscrasias. Diffusion-weighted imaging provides information on diffusion (restriction) of water molecules in bone marrow and in malignant infiltration. Qualitative evaluation by visually assessing images with different diffusion sensitising gradients and quantitative evaluation of the apparent diffusion coefficient are studied extensively. Dynamic contrast-enhanced imaging provides information on bone marrow vascularisation, perfusion, capillary resistance, vascular permeability and interstitial space, which are systematically altered in different disease stages and can be evaluated in a qualitative and a (semi-)quantitative manner. Both diffusion restriction and abnormal dynamic contrast-enhanced MRI parameters are early biomarkers of malignancy or disease progression in focal lesions or in regions with diffuse abnormal signal intensities. The added value for both techniques lies in better detection and/or characterisation of abnormal bone marrow otherwise missed or misdiagnosed on anatomical MRI sequences. Increased detection rates of focal lesions or diffuse bone marrow infiltration upstage patients to higher disease stages, provide earlier access to therapy and slower disease progression and allow closer monitoring of high-risk patients. Despite promising results, variations in imaging protocols, scanner types and post-processing methods are large, thus hampering universal applicability and reproducibility of quantitative imaging parameters. The myeloma response assessment and diagnosis system and the international myeloma working group provide a systematic multicentre approach on imaging and propose which parameters to use in multiple myeloma and its precursors in an attempt to overcome the pitfalls of dynamic contrast-enhanced and diffusion-weighted imaging.Single sentence summary statementDiffusion-weighted imaging and dynamic contrast-enhanced MRI provide important additional information to standard anatomical MRI techniques for diagnosis, staging and follow-up of patients with plasma cell dyscrasias, although some precautions should be taken on standardisation of imaging protocols to improve reproducibility and application in multiple centres.

Bone Metastases Are Measurable: The Role of Whole-Body MRI and Positron Emission Tomography

Metastatic tumor deposits in bone marrow elicit differential bone responses that vary with the type of malignancy. This results in either sclerotic, lytic, or mixed bone lesions, which can change in morphology due to treatment effects and/or secondary bone remodeling. Hence, morphological imaging is regarded unsuitable for response assessment of bone metastases and in the current Response Evaluation Criteria In Solid Tumors 1.1 (RECIST1.1) guideline bone metastases are deemed unmeasurable. Nevertheless, the advent of functional and molecular imaging modalities such as whole-body magnetic resonance imaging (WB-MRI) and positron emission tomography (PET) has improved the ability for follow-up of bone metastases, regardless of their morphology. Both these modalities not only have improved sensitivity for visual detection of bone lesions, but also allow for objective measurements of bone lesion characteristics. WB-MRI provides a global assessment of skeletal metastases and for a one-step "all-organ" approach of metastatic disease. Novel MRI techniques include diffusion-weighted imaging (DWI) targeting highly cellular lesions, dynamic contrast-enhanced MRI (DCE-MRI) for quantitative assessment of bone lesion vascularization, and multiparametric MRI (mpMRI) combining anatomical and functional sequences. Recommendations for a homogenization of MRI image acquisitions and generalizable response criteria have been developed. For PET, many metabolic and molecular radiotracers are available, some targeting tumor characteristics not confined to cancer type (e.g. 18F-FDG) while other targeted radiotracers target specific molecular characteristics, such as prostate specific membrane antigen (PSMA) ligands for prostate cancer. Supporting data on quantitative PET analysis regarding repeatability, reproducibility, and harmonization of PET/CT system performance is available. Bone metastases detected on PET and MRI can be quantitatively assessed using validated methodologies, both on a whole-body and individual lesion basis. Both have the advantage of covering not only bone lesions but visceral and nodal lesions as well. Hybrid imaging, combining PET with MRI, may provide complementary parameters on the morphologic, functional, metabolic and molecular level of bone metastases in one examination. For clinical implementation of measuring bone metastases in response assessment using WB-MRI and PET, current RECIST1.1 guidelines need to be adapted. This review summarizes available data and insights into imaging of bone metastases using MRI and PET.

Oncologically Relevant Findings Reporting and Data System (ONCO-RADS): Guidelines for the Acquisition, Interpretation, and Reporting of Whole-Body MRI for Cancer Screening

Acknowledging the increasing number of studies describing the use of whole-body MRI for cancer screening, and the increasing number of examinations being performed in patients with known cancers, an international multidisciplinary expert panel of radiologists and a geneticist with subject-specific expertise formulated technical acquisition standards, interpretation criteria, and limitations of whole-body MRI for cancer screening in individuals at higher risk, including those with cancer predisposition syndromes. The Oncologically Relevant Findings Reporting and Data System (ONCO-RADS) proposes a standard protocol for individuals at higher risk, including those with cancer predisposition syndromes. ONCO-RADS emphasizes structured reporting and five assessment categories for the classification of whole-body MRI findings. The ONCO-RADS guidelines are designed to promote standardization and limit variations in the acquisition, interpretation, and reporting of whole-body MRI scans for cancer screening. Published under a CC BY 4.0 license Online supplemental material is available for this article.

Repeatability and reproducibility of ADC measurements: a prospective multicenter whole-body-MRI study

OBJECTIVES

Multicenter oncology trials increasingly include MRI examinations with apparent diffusion coefficient (ADC) quantification for lesion characterization and follow-up. However, the repeatability and reproducibility (R&R) limits above which a true change in ADC can be considered relevant are poorly defined. This study assessed these limits in a standardized whole-body (WB)-MRI protocol.

METHODS

A prospective, multicenter study was performed at three centers equipped with the same 3.0-T scanners to test a WB-MRI protocol including diffusion-weighted imaging (DWI). Eight healthy volunteers per center were enrolled to undergo test and retest examinations in the same center and a third examination in another center. ADC variability was assessed in multiple organs by two readers using two-way mixed ANOVA, Bland-Altman plots, coefficient of variation (CoV), and the upper limit of the 95% CI on repeatability (RC) and reproducibility (RDC) coefficients.

RESULTS

CoV of ADC was not influenced by other factors (center, reader) than the organ. Based on the upper limit of the 95% CI on RC and RDC (from both readers), a change in ADC in an individual patient must be superior to 12% (cerebrum white matter), 16% (paraspinal muscle), 22% (renal cortex), 26% (central and peripheral zones of the prostate), 29% (renal medulla), 35% (liver), 45% (spleen), 50% (posterior iliac crest), 66% (L5 vertebra), 68% (femur), and 94% (acetabulum) to be significant.

CONCLUSIONS

This study proposes R&R limits above which ADC changes can be considered as a reliable quantitative endpoint to assess disease or treatment-related changes in the tissue microstructure in the setting of multicenter WB-MRI trials.

KEY POINTS

• The present study showed the range of R&R of ADC in WB-MRI that may be achieved in a multicenter framework when a standardized protocol is deployed. • R&R was not influenced by the site of acquisition of DW images. • Clinically significant changes in ADC measured in a multicenter WB-MRI protocol performed with the same type of MRI scanner must be superior to 12% (cerebrum white matter), 16% (paraspinal muscle), 22% (renal cortex), 26% (central zone and peripheral zone of prostate), 29% (renal medulla), 35% (liver), 45% (spleen), 50% (posterior iliac crest), 66% (L5 vertebra), 68% (femur), and 94% (acetabulum) to be detected with a 95% confidence level.

Detection and Characterization of Musculoskeletal Cancer Using Whole-Body Magnetic Resonance Imaging

Whole-body magnetic resonance imaging (WB-MRI) is gradually being integrated into clinical pathways for the detection, characterization, and staging of malignant tumors including those arising in the musculoskeletal (MSK) system. Although further developments and research are needed, it is now recognized that WB-MRI enables reliable, sensitive, and specific detection and quantification of disease burden, with clinical applications for a variety of disease types and a particular application for skeletal involvement. Advances in imaging techniques now allow the reliable incorporation of WB-MRI into clinical pathways, and guidelines recommending its use are emerging. This review assesses the benefits, clinical applications, limitations, and future capabilities of WB-MRI in the context of other next-generation imaging modalities, as a qualitative and quantitative tool for the detection and characterization of skeletal and soft tissue MSK malignancies.

Differentiating atypical hemangiomas and vertebral metastases: a field-of-view (FOV) and FOCUS intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) study

PURPOSE

Some atypical vertebral hemangiomas (VHs) may mimic metastases on routine MRI and can result in misdiagnosis and ultimately to additional imaging, biopsy and unnecessary costs. The purpose of this study is to assess the utility of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) on account of field-of-view optimized and constrained undistorted single shot (FOCUS) in distinguishing atypical VHs and vertebral metastases.

METHODS

A total of 25 patients with vertebral metastases and 25 patients with atypical VHs were confirmed by clinical follow-up or pathology. IVIM-DWI imaging was performed at different b values (0, 30, 50, 100, 150, 200, 400, 600, 800, 1000 mm²/s). IVIM parameters [the true diffusion coefficient (D), pseudodiffusion coefficient (D*), standard apparent diffusion coefficient (ADC), and perfusion fraction (f)] were calculated and compared between two groups by using Student's t test. A receiver operating characteristic analysis was performed.

RESULTS

Quantitative analysis of standard ADC and D parameters showed significantly lower values in vertebral metastases when compared to atypical hemangiomas [ADC value: (0.70 ± 0.12) × 10^-3 mm²/s vs (1.14 ± 0.28) × 10^-3 mm²/s; D value: (0.47 ± 0.07) × 10^-3 mm²/s vs (0.76 ± 0.14) × 10^-3 mm²/s, all P < 0.01]. The sensitivity and specificity of D value were 93.8% and 92.3%, respectively.

CONCLUSION

The standard ADC value and D value may be used as an indicator to distinguish vertebral metastases from atypical VHs. FOCUS IVIM-derived parameters provide potential value in the quantitatively differentiating vertebral metastases from vertebral atypical hemangiomas.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

KEY POINTS

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

THE ROLE OF DIFFUSION-WEIGHTED MRI OF PATIENTS WITH SPINE METASTASES

ABSTRACT Objective: The role of diffusion-weighted MRI in differential diagnostics and predicting the survival of patients with spine metastases was studied. Methods: The study included data from MRI and morphological studies of 23 patients with spine metastases. Results: The values obtained for the apparent diffusion coefficient (ADC) of tumors were compared with their histological type, cell density and Ki-67 proliferation index. The effect of ADC values on overall patient survival was also assessed. A reliable inverse correlation was established between ADC values and Ki-67 proliferation index for various types of spine metastases (r=-0.753, p=0.017). The dependence of ADC values and overall survival of patients with metastases in the spine is shown. Conclusion: The technique of diffusion-weighted MRI can be used as part of a comprehensive assessment in the preoperative planning of surgical treatment, and as a prognostic factor of overall survival for this group of patients. Level of Evidence II. Prognostic retrospective study,

Usefulness of Diffusion-Weighted Magnetic Resonance Imaging Using Apparent Diffusion Coefficient Values for Diagnosis of Infantile Hemangioma

OBJECTIVE

The objective of this study was to determine whether apparent diffusion coefficient (ADC) values obtained from diffusion-weighted imaging allow differentiation between infantile hemangiomas (IHs) and malignant soft tissue tumors.

METHODS

A retrospective review was performed on magnetic resonance images of pediatric patients with IHs and malignant soft tissue tumors from January 2014 to December 2016, which comprised 7 patients with 8 IHs and 6 patients with 6 malignant soft tissue tumors. We calculated and compared the ADC values of each lesion. Receiver operating characteristic curve analysis was performed to determine a cutoff value for the ADC.

RESULTS

There was a statistically significant difference between the ADC values of IHs and those of malignant soft tissue tumors (1.32 [1.27-1.72] × 10 mm/s vs 0.67 [0.57-0.79] × 10 mm/s; P < 0.001), with no overlap between the 2 groups.

CONCLUSIONS

The ADC values obtained from diffusion-weighted imaging were useful in differentiating IHs from malignant soft tissue tumors in pediatric patients.

Guidelines for Acquisition, Interpretation, and Reporting of Whole-Body MRI in Myeloma: Myeloma Response Assessment and Diagnosis System (MY-RADS)

Acknowledging the increasingly important role of whole-body MRI for directing patient care in myeloma, a multidisciplinary, international, and expert panel of radiologists, medical physicists, and hematologists with specific expertise in whole-body MRI in myeloma convened to discuss the technical performance standards, merits, and limitations of currently available imaging methods. Following guidance from the International Myeloma Working Group and the National Institute for Clinical Excellence in the United Kingdom, the Myeloma Response Assessment and Diagnosis System (or MY-RADS) imaging recommendations are designed to promote standardization and diminish variations in the acquisition, interpretation, and reporting of whole-body MRI in myeloma and allow response assessment. This consensus proposes a core clinical protocol for whole-body MRI and an extended protocol for advanced assessments. Published under a CC BY 4.0 license. Online supplemental material is available for this article.

Whole-body MRI to assess bone involvement in prostate cancer and multiple myeloma: comparison of the diagnostic accuracies of the T1, short tau inversion recovery (STIR), and high b-values diffusion-weighted imaging (DWI) sequences

PURPOSE

To compare the diagnostic accuracy of whole-body T1, short tau inversion recovery (STIR), high b-value diffusion-weighted imaging (DWI), and sequence combinations to detect bone involvement in prostate cancer (PCa) and multiple myeloma (MM) patients.

MATERIALS AND METHODS

We included 50 consecutive patients with PCa at high risk for metastasis and 47 consecutive patients with a histologically confirmed diagnosis of MM who received whole-body MRI at two institutions from January to December 2015. Coronal T1, STIR, and reconstructed coronal high b-values DWI were obtained for all patients. Two musculoskeletal radiologists read individual sequences, pairs of sequences (T1-DWI, T1-STIR, and STIR-DWI), and all combined (T1-STIR-DWI) to detect bone involvement. Receiver operating characteristic curve analysis was used to assess diagnostic performance according to a "best valuable comparator" combining baseline and 6-month imaging and clinical and biological data. Interobserver agreement was calculated.

RESULTS

Interobserver agreement for individual and combined MRI sequences was very good in the PCa group and ranged from good to very good in the MM group (0.76-1.00). In PCa patients, T1-DWI, T1-STIR, and T1-STIR-DWI showed the highest performance (sensitivity = 100% [95% CI = 90.5-100%], specificity = 100% [75.3-100%]). In MM patients, the highest performance was achieved by T1-STIR-DWI (sensitivity = 100% [88.4-100%], specificity = 94.1% [71.3-100%]). T1-STIR-DWI significantly outperformed all sequences (p < 0.05) except T1-DWI (p = 0.49).

CONCLUSION

In PCa patients, a combination of either T1-DWI or T1-STIR sequences is not inferior to a combination of three sequences to detect bone metastases. In MM, T1-STIR-DWI and T1-DWI had the highest diagnostic performance for detecting bone involvement.

KEY POINTS

• The sequences used in Whole Body MRI studies to detect bone involvement in prostate cancer and myeloma were evaluated. • In prostate cancer, any pairwise combinations of T1, STIR, and DWI have high diagnostic value. • In myeloma, the combinations T1-STIR-DWI or T1-DWI sequences should be used.

Quantitative Whole-Body Diffusion-Weighted MR Imaging

Whole-body diffusion-weighted MRI has emerged as a powerful diagnostic tool for disease detection and staging mainly used in systemic bone disease. The large field-of-view functional imaging technique highlights cellular tumor and suppresses normal tissue signal, allowing quantification of an estimate of total disease burden, summarized as the total diffusion volume (tDV), as well as global apparent diffusion coefficient (gADC) measurements. Both tDV and gADC have been shown to be repeatable quantitative parameters that indicate tumor heterogeneity and treatment effects, thus potential, noninvasive, imaging biomarkers informing on disease prognosis and therapy response.