Acute vertebral body compression fractures: discrimination between benign and malignant causes using apparent diffusion coefficients

Rate of Unexpected Malignancy in Patients Undergoing Percutaneous Vertebroplasty after Implementing a New Scanning Protocol

STUDY DESIGN

Retrospective quality improvement study.

OBJECTIVE

To investigate if the rate of unsuspected malignancy in biopsies in patients with VCF who underwent percutaneous vertebroplasty (PVP) at the same orthopedic department has changed after the implementation of a new MRI scanning protocol.

SUMMARY OF BACKGROUND DATA

Discrimination between benign and malign vertebral compression fracture (VCF) can be difficult. However, early diagnosis of malignant VCF is crucial to further treatment and prognosis. An earlier study at an orthopedic department reported a rate of unsuspected malignancy of 4.9% in patients with VCF who underwent PVP when biopsies were obtained during the procedure. The MRI scanning protocol was changed in this period.

METHODS

Retrospective on 427 patients with vertebral compression fracture undergoing PVP from April 28, 2017 to April 28, 2022, identifying operated patients from the Danish national DaneSpine registry. Subsequently, individual clinical information was collected in journal records.

RESULTS

The rate of unsuspected malignancy was 0.9% (4/427), and the overestimation of malignant VCF was 50% (16/32).

CONCLUSION

During the last 5 years, the rate of unsuspected malignancy in patients with VCF undergoing PVP has improved considerably from 4.9% to 0.9%. Furthermore, MRI is over-diagnosing malignancies. Thus, the new scanning procedure is effective in differentiating between benign and malign VCFs.

LEVEL OF EVIDENCE

3.

Echo-planar DWI variants: A comparative study in vertebral marrow pathology

PURPOSE

Single-shot echo-planar imaging (ss-EPI) has limited application in vertebral column imaging due to numerous artifacts. Therefore, we aimed to compare readout-segmented echo-planar imaging (rs-EPI) to ss-EPI and assess its value in the differential diagnosis of vertebral infectious, tumoral infiltrative, and degenerative disorders.

MATERIALS AND METHODS

Sixty-six adult patients with spondylodiscitis (SD, n = 26), tumoral infiltration (TI, n = 20), or Modic type I degeneration (DE, n = 20) findings on spinal magnetic resonance imaging (MRI) included in this retrospective study. Two radiologists scored images for quality on a 4-point scale (image resolution, degree of geometric distortion, lesion selectivity, and diagnostic reliability) and measured signal intensity (SI), apparent diffusion coefficient (ADC), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). DE and SD groups also united to form the benign group.

RESULTS

In all groups, rs-EPI performed better than ss-EPI in image quality, SNR, and CNR (p < .05). The difference between mean pathological ADC (ADCP) in the two sequences was statistically significant (p < .05). There was no significant difference between the groups in terms of ADCP in rs-EPI (p = .229), unlike ss-EPI (p = .025). Pathological SI (SIP) and CNR in rs-EPI were significantly higher in the malignant group than benign group (p = .002, p < .001). In rs-EPI, no significant difference was found between malignant and benign groups' ADCP (p = .13).

CONCLUSION

The rs-EPI is a diffusion-weighted imaging (DWI) method with higher image quality that diminishes motion-induced phase errors and increases resolution through phase corrections. However, the distinction of malignant and benign vertebral bone marrow pathologies is unsatisfactory for rs-EPI compared with ss-EPI.

Multiparametric quantification of T1 and T2 relaxation time of bone metastasis in comparison with red or fatty bone marrow using magnetic resonance fingerprinting

OBJECTIVES

To assess the T1 and T2 values of bone marrow lesions in spine and pelvis derived from magnetic resonance fingerprinting (MRF) and to evaluate the differences in values among bone metastasis, red marrow and fatty marrow.

METHODS

Sixty patients who underwent lumbar spine and pelvic MRI with magnetic resonance fingerprinting were retrospectively included. Among eligible patients, those with bone metastasis, benign red marrow deposition and normal fatty marrow were identified. Two radiologists independently measured the T1 and T2 values from metastatic bone lesions, fatty marrow, and red marrow deposition on three-dimensional-magnetic resonance fingerprinting. Intergroup comparison and interobserver agreement were analyzed.

RESULTS

T1 relaxation time was significantly higher in osteoblastic metastasis than in red marrow (1674.6 ± 436.3 vs 858.7 ± 319.5, p < .001). Intraclass correlation coefficients for T1 and T2 values were 0.96 (p < 0.001) and 0.83 (p < 0.001), respectively. T2 relaxation time of osteoblastic metastasis and red marrow deposition had no evidence of a difference (osteoblastic metastasis, 57.9 ± 25.0 vs red marrow, 58.0 ± 34.4, p = 0.45), as were the average T2 values of osteolytic metastasis and red marrow deposition (osteolytic metastasis, 45.3 ± 15.1 vs red marrow, 58.0 ± 34.4, p = 0.63).

CONCLUSIONS

We report the feasibility of three-dimensional-magnetic resonance fingerprinting based quantification of bone marrow to differentiate bone metastasis from red marrow. Simultaneous T1 and T2 quantification of metastasis and red marrow deposition was possible in spine and pelvis and showed significant different values with excellent inter-reader agreement.

ADVANCE IN KNOWLEDGE

T1 values from three-dimensional-magnetic resonance fingerprinting might be a useful quantifier for evaluating bone marrow lesions.

Comparison between ZOOMit DWI and conventional DWI in the assessment of foot and ankle infection: a prospective study

OBJECTIVE

The study aimed to compare ZOOMit diffusion-weighted imaging (DWI) MRI with conventional DWI MRI for visualizing small bones in the foot, soft tissue abscesses, and osteomyelitis.

MATERIALS AND METHODS

The cohort consisted of a consecutive series of patients with potential foot and ankle infections referred for MR imaging. Patients were imaged using both conventional and ZOOMit DWI in the same setting. Blinded reads were then conducted in separate settings and independent of known clinical diagnosis by two expert radiologists. The results from the reads were compared statistically using paired t-tests and with biopsy specimen analysis, both anatomopathological and microbiological.

RESULTS

There was improvement in fat suppression using ZOOMit sequence compared to conventional DWI (p = .001) with no significant difference in motion artifacts (p = .278). ZOOMit had a higher rate of concordance with pathology findings for osteomyelitis (72%, 31/43 cases) compared with conventional DWI (60%, 26/43 cases). ZOOMit also identified 46 additional small bones of the foot and ankle (405/596, 68.0%) than conventional DWI (359/596, 60.2%). Conventional DWI however exhibited a more negative contrast-to-noise ratio (CNR) than ZOOMit (p = 0.001).

CONCLUSION

ZOOMit DWI improves distal extremity proton diffusion assessment and helps visualize more bones in the foot, with less image distortion and improved fat saturation at the expense of reduced CNR. This makes it a viable option for assessing lower extremity infections.

CLINICAL RELEVANCE STATEMENT

This study highlights the novel utilization of ZOOMit diffusion-weighted imaging (DWI) for the assessment of lower extremity lesions compared to conventional DWI.

KEY POINTS

• Distal extremity diffusion-weighted imaging (DWI) is often limited. • ZOOMit DWI displayed improved fat suppression with less motion artifacts and better visualization of the lower extremity bones than conventional DWI. • ZOOMit shows decreased contrast-to-noise ratio than conventional DWI.

Diffusion-Weighted Imaging and Chemical Shift Imaging to Differentiate Benign and Malignant Vertebral Lesion: A Hospital-Based Cross-Sectional Study

Objective  The aim of this study was to evaluate the role of diffusion-weighted imaging (DWI) and chemical shift imaging (CSI) for the differentiation of benign and malignant vertebral lesions. Methods  Patients with vertebral lesions underwent routine magnetic resonance imaging (MRI) along with DWI and CSI. Qualitative analysis of the morphological features was done by routine MRI. Quantitative analysis of apparent diffusion coefficient (ADC) from DWI and fat fraction (FF) from CSI was done and compared between benign and malignant vertebral lesions. Results  Seventy-two patients were included. No significant difference was noted in signal intensities of benign and malignant lesions on conventional MRI sequences. Posterior element involvement, paravertebral soft-tissue lesion, and posterior vertebral bulge were common in malignant lesion, whereas epidural/paravertebral collection, absence of posterior vertebral bulge, and multiple compression fractures were common in benign vertebral lesion ( p  < 0.001). The mean ADC value was 1.25 ± 0.27 mm 2 /s for benign lesions and 0.9 ± 0.19 mm 2 /s for malignant vertebral lesions ( p ≤ 0.001). The mean value of FF was 12.7 ± 7.49 for the benign group and 4.04 ± 2.6 for the malignant group ( p  < 0.001). A receiver operating characteristic (ROC) curve analysis showed that an ADC cutoff of 1.05 × 10 -3 mm 2 /s and an FF cutoff of 6.9 can differentiate benign from malignant vertebral lesions, with the former having 86% sensitivity and 82.8% specificity and the latter having 93% sensitivity and 96.6% specificity. Conclusion  The addition of DWI and CSI to routine MRI protocol in patients with vertebral lesions promises to be very helpful in differentiating benign from malignant vertebral lesions when difficulty in qualitative interpretation of conventional MR images arises.

The advancement of MRI in differentiating Modic type I degenerative changes from early spinal infections

MRI is the most sensitive and specific imaging method for the detection of advanced spinal infections. However, the differential diagnosis of early spinal infection and Modic Type I degenerative changes based on conventional MRI is difficult clinically, as they both may mimic each other by showing hypointensity on T1 weighted images and hyperintensity on T2 weighted spine MRI images. This review summarizes recent advancements in MRI, which may be useful in discriminating degenerative Modic Type I endplate changes from early spinal infection, and evaluates the diagnostic accuracy and limitations of MRI. We aim to provide indications for early differential diagnosis to help initiate appropriate treatment in a timely manner so that associated complications can be avoided.

Role of advanced MRI techniques for sacroiliitis assessment and quantification

The introduction of MRI was supposed to be a qualitative leap for the evaluation of Sacroiliac Joint (SIJ) in patients with Axial Spondyloarthropathies (AS). In fact, MRI findings such as bone marrow edema around the SIJ has been incorporated into the Assessment in SpondyloArthritis International Society (ASAS criteria). However, in the era of functional imaging, a qualitative approach to SIJ by means of conventional MRI seems insufficient. Advanced MRI sequences, which have successfully been applied in other anatomical areas, are demonstrating their potential utility for a more precise assessment of SIJ. Dixon sequences, T2-mapping, Diffusion Weighted Imaging or DCE-MRI can be properly acquired in the SIJ with promising and robust results. The main advantage of these sequences resides in their capability to provide quantifiable parameters that can be used for diagnosis of AS, surveillance or treatment follow-up. Further studies are needed to determine if these parameters can also be integrated into ASAS criteria for reaching a more precise classification of AS based not only on visual assessment of SIJ but also on measurable data.

Diffusion-weighted magnetic resonance imaging in differentiation between different vertebral lesions using ADC mapping as a quantitative assessment tool

Background

Diffusion-weighted imaging is one of the most useful clinical MRI techniques. Including this technique with other sequences used for routine spine scanning improves sensitivity and the capacity to characterize lesions. This study aims to evaluate the utility of apparent diffusion coefficient obtained from diffusion-weighted MR imaging in differentiating between benign and malignant vertebral lesions according to the optimal cutoff ADC value.

Results

This study included 30 patients at Ain Shams University hospitals; all of them were subjected to full clinical assessment and magnetic resonance imaging. Patients were classified into 4 groups: inflammatory lesions (12 cases) followed by malignant lesions (7 cases), then benign neoplastic lesions (6 cases), then traumatic lesions (3 cases) and osteoporosis (two cases). Inflammatory lesions revealed restricted diffusion. Benign neoplastic lesions/hemangioma showed low signal at DWIs due to free diffusion, while malignant/metastatic lesions showed restricted diffusion. Traumatic lesions showed restricted diffusion. The osteoporotic lesions showed iso- to hyper-intense signal at DWIs. The mean ADC value of the benign lesions was 1.8 ± 0.43 mm2/s, while metastatic tumors was 0.96 ± 0.5 × 10–3 mm2/s; however, overlapping values may be present.

Conclusions

Compared with benign tumors, malignant tumors have lower ADC values; nevertheless, some lesions, such as tuberculosis, have low ADC values that are like those of malignant tumors. Diffusion MRI and ADC values should always be analyzed in conjunction with standard MRI sequences as well as a thorough clinical history and examination.

Intravoxel incoherent motion to differentiate spinal metastasis: A pilot study

Background

To investigate the value of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) to discriminate spinal metastasis from tuberculous spondylitis.

Methods

This study included 50 patients with spinal metastasis (32 lung cancer, 7 breast cancer, 11 renal cancer), and 20 with tuberculous spondylitis. The IVIM parameters, including the single-index model (apparent diffusion coefficient (ADC)-stand), double exponential model (ADCslow, ADCfast, and f), and the stretched-exponential model parameters (distributed diffusion coefficient (DDC) and α), were acquired. Receiver operating characteristic (ROC) and the area under the ROC curve (AUC) analysis was used to evaluate the diagnostic performance. Each parameter was substituted into a logistic regression model to determine the meaningful parameters, and the combined diagnostic performance was evaluated.

Results

The ADCfast and f showed significant differences between spinal metastasis and tuberculous spondylitis (all p &lt; 0.05). The logistic regression model results showed that ADCfast and f were independent factors affecting the outcome (P &lt; 0.05). The AUC values of ADCfast and f were 0.823 (95% confidence interval (CI): 0.719 to 0.927) and 0.876 (95%CI: 0.782 to 0.969), respectively. ADCfast combined with f showed the highest AUC value of 0.925 (95% CI: 0.858 to 0.992).

Conclusions

IVIM MR imaging might be helpful to differentiate spinal metastasis from tuberculous spondylitis, and provide guidance for clinical treatment.

Semi-automatic quantitative analysis of the pelvic bony structures on apparent diffusion coefficient maps based on deep learning: establishment of reference ranges

BACKGROUND

Apparent diffusion coefficient (ADC) maps provide quantitative information on both normal and abnormal tissues. However, it is difficult to distinguish between these tissues unless consistent and precise ADC values can be obtained from normal tissues. For this study we developed a deep learning-based convolutional neural network (CNN) for pelvic bony structure segmentation and established the reference ranges of ADC parameters for normal pelvic bony structures.

METHODS

We retrospectively enrolled 767 prostate cancer (PCa) patients for quantitative ADC analyses of normal pelvic bony structures. A subset of 288 patients who did not receive treatment for PCa (S1) were used to develop a CNN model for the segmentation of 8 pelvic bony structures (lumbar vertebra, sacrococcyx, ilium, acetabulum, femoral head, femoral neck, ischium, and pubis). The proposed CNN was used for the automated segmentation of these pelvic bony structures from a subset of 405 patients who did not receive treatment (S2) and 74 patients who received treatment [radiotherapy (S3) or endocrine therapy (S4)]. The 95% confidence interval (CI) was used to establish reference ranges for the ADC values from the normal pelvic bony structures of S1 and S2.

RESULTS

The Dice scores (Sørensen-Dice coefficient) for the CNN segmentation of the 8 pelvic bones on the ADC maps ranged from 0.90±0.02 (ilium) to 0.95±0.03 (femoral head) in the S1 testing set. In the S2 data set, the Dice scores showed no significant difference among the different scanners (P>0.05), and no significant differences were found among the S2, S3, and S4 data sets. The correlation analysis revealed that the b value and field strength were significantly correlated with ADC values (all P<0.001), while age and treatment were not significant variables (all P>0.05). The ADC reference ranges (95% CI) were as follows: lumbar vertebra, 1.11 (0.90-1.54); sacrococcyx, 0.82 (0.61-1.15); ilium, 0.57 (0.45-0.62); acetabulum, 0.59 (0.40-0.69); femoral head, 0.46 (0.25-0.58); femoral neck, 0.43 (0.25-0.48); ischium, 0.45 (0.26-0.55); and pubis, 0.57 (0.45-0.65).

CONCLUSIONS

This study preliminarily established reference ranges for the ADC values of normal pelvic bony structures. The image acquisition parameters had an influence on the ADC values.

Radiation-induced occult insufficiency fracture or bone metastasis after radiotherapy for cervical cancer? The nomogram based on quantitative apparent diffusion coefficients for discrimination

Background

Radiation-induced insufficiency fractures (IF) is frequently occult without fracture line, which may be mistaken as metastasis. Quantitative apparent diffusion coefficient (ADC) shows potential value for characterization of benign and malignant bone marrow diseases. The purpose of this study was to develop a nomogram based on multi-parametric ADCs in the differntiation of occult IF from bone metastasis after radiotherapy (RT) for cervical cancer.

Methods

This study included forty-seven patients with cervical cancer that showed emerging new bone lesions in RT field during the follow-up. Multi-parametric quantitative ADC values were measured for each lesion by manually setting region of interests (ROIs) on ADC maps, and the ROIs were copied to adjacent normal muscle and bone marrow. Six parameters were calculated, including ADC_mean, ADC_min, ADC_max, ADC_std, ADC_mean ratio (lesion/normal bone) and ADC_mean ratio (lesion/muscle). For univariate analysis, receiver operating characteristic curve (ROC) analysis was performed to assess the performance. For combined diagnosis, a nomogram model was developed by using a multivariate logistic regression analysis.

Results

A total of 75 bone lesions were identified, including 48 occult IFs and 27 bone metastases. There were significant differences in the six ADC parameters between occult IFs and bone metastases (p < 0.05), the ADC ratio (lesion/ muscle) showed an optimal diagnostic efficacy, with an area under ROC (AUC) of 0.887, the sensitivity of 95.8%, the specificity of 81.5%, respectively. Regarding combined diagnosis, ADC_std and ADC_mean ratio (lesion/muscle) were identified as independent factors and were selected to generate a nomogram model. The nomogram model showed a better performance, yielded an AUC of 0.92, the sensitivity of 91.7%, the specificity of 96.3%, positive predictive value (PPV) of 97.8% and negative predictive value (NPV) of 86.7%, respectively.

Conclusions

Multi-parametric ADC values demonstrate potential value for differentiating occult IFs from bone metastasis, a nomogram based on the combination of ADC_std and ADC_mean ratio (lesion/muscle) may provide an improved classification performance.

Dixon or DWI - Comparing the utility of fat fraction and apparent diffusion coefficient to distinguish between malignant and acute osteoporotic vertebral fractures

PURPOSE

To compare fat fraction (FF) and apparent diffusion coefficient (ADC) as discriminators distinguishing malignant from acute/subacute osteoporotic vertebral fractures.

METHOD

1.5 T MRIs of 42 malignant and 27 acute/subacute osteoporotic vertebral fractures (38 patients) were retrospectively reviewed. Two readers independently classified fractures as malignant or osteoporotic based on conventional imaging morphology. Diagnostic reader confidence was rated as confident or not confident. FF was derived from axial T1 gradient-echo 2-point Dixon MRI. ADC maps were calculated from axial b50 and b900 images. Both readers independently performed ROI measurements of mean FF and ADC of the same fractured vertebrae. FF and ADC values, corresponding ROC curves and optimized cut-off value performance were compared. Inter-reader agreement was analysed by calculation of intraclass correlation coefficients (ICCs). A p-value < 0.05 was deemed significant.

RESULTS

Mean FF and ADC were significantly lower in malignant (9.5 % and 1.05 × 10^-3 mm²/s) compared to osteoporotic fractures (32 % and 1.34 × 10^-3 mm²/s, all p < 0.001). The optimal cut-off FF was 11.5 %, detecting malignant fractures with 86 %/89 % sensitivity/specificity. The optimal ADC cut-off of 1.04 × 10^-3 mm/s² yielded 62 %/96 % sensitivity/specificity. FF AUC (0.93) was significantly larger than ADC AUC (0.82, p = 0.03). In the subgroup of nine cases reported with low expert reader confidence, the optimized cut-off specificities of FF (83 %) and ADC (83 %) exceeded reader specificity (50 %). There was excellent inter-reader agreement for mean FF (ICC = 0.99) and good agreement for mean ADC (ICC = 0.86) measurements.

CONCLUSION

FF and ADC can improve reader specificity to distinguish between malignant and acute or subacute osteoporotic vertebral fractures. As single discriminator, FF was superior to ADC.

Pelvic insufficiency fracture or bone metastasis after radiotherapy for cervical cancer? The added value of DWI for characterization

OBJECTIVES

We sought to determine the added value of diffusion-weighted magnetic resonance imaging (DWI) in the differentiation of pelvic insufficiency fracture (PIF) from bone metastasis after radiotherapy in cervical cancer patients.

METHODS

In the present study, 42 cervical cancer patients after radiotherapy with 61 bone lesions (n = 40, PIFs; n = 21, bone metastasis) were included. Conventional MRI and DWI were performed in all patients. For qualitative imaging diagnosis, two sets of images were reviewed independently by three observers, including a conventional MRI set (unenhanced T1-weighted, T2-weighted, and enhanced T1-weighted images) and a DWI set (conventional MRIs, DW images, and ADC maps). The mean ADC value of each lesson was measured on ADC maps. The diagnostic performance was assessed by using the area under the receiver operating characteristic curve (A_z), and sensitivity and specificity were determined.

RESULTS

For all observers, the A_z value and sensitivity of the DWI set showed improvement compared with the conventional MRI set. The observer who had the least experience (3 years) demonstrated significant improvement in diagnostic performance with the addition of DWI; A_z value increased from 0.804 to 0.915 (p = 0.042) and sensitivity increased from 75.0 to 92.5% (p = 0.035). The mean ADCs of the PIFs were significantly higher than the bone metastases (p < 0.001); ADC values > 0.97 × 10^-3 mm²/s yielded an A_z of 0.887, a sensitivity of 92.5%, and a specificity of 76.2%.

CONCLUSIONS

The addition of DWI to conventional MRI improved the differentiation of PIF from bone metastasis after RT in patients with cervical cancer.

KEY POINTS

• DWI showed additive value to conventional MRI in the differentiation of PIF from bone metastasis after RT. • For qualitative diagnosis, the addition of DWI can improve diagnostic performance compared with conventional MRI alone and can particularly improve the sensitivity. • Quantitative ADC assessment showed potential value for identifying PIF from bone metastasis.

Comparison of proton density fat fraction, simultaneous R2*, and apparent diffusion coefficient for assessment of focal vertebral bone marrow lesions

AIM

To investigate the diagnostic performance of proton density fat fraction (PDFF) and simultaneous R2* for focal vertebral bone marrow lesion (VBML) assessment, compared with the apparent diffusion coefficient (ADC).

MATERIALS AND METHODS

One hundred and ninety-two spinal magnetic resonance imaging (MRI) examinations performed in 126 patients with focal VBMLs from March 2016 to November 2018 were reviewed retrospectively. The lesions were divided into metastases and benign VBMLs. The protocol consisted of routine morphological MRI sequences, followed by complex-based chemical shift imaging (CSE)-MRI and diffusion-weighted (DW)-MRI with a 1.5 T system. PDFF, R2*, and the ADC values were compared using the Mann-Whitney U-test. Receiver operating characteristic curve analysis was carried out to assess the diagnostic performance for differentiating metastases from focal benign VBMLs.

RESULTS

PDFF, R2*, and mean ADC values in metastases were significantly lower than those in benign VBMLs (p<0.05). The PDFF (area under the curve [AUC]= 0.968; 95% confidence interval [CI]=0.932-0.988) showed a significantly larger AUC compared with R2* (AUC=0.670; 95% CI=0.599-0.736) and ADC (AUC=0.801; 95% CI=0.738-0.855). The optimal cut-off value of the PDFF for predicting metastases was 9%; this threshold corresponded to a sensitivity of 96.67%, specificity of 90.28%, and accuracy of 94.27%.

CONCLUSION

PDFF is significantly more accurate than ADC and R2* for differentiating focal benign VMBLs from metastases.

Intravoxel incoherent motion MR imaging for differentiating malignant lesions in spine: A pilot study

PURPOSE

To determine the diagnostic potential of Intravoxel Incoherent Motion (IVIM) MRI for differentiating malignant spinal tumours from acute vertebral compression fractures and tuberculous spondylitis, and to compare IVIM with diffusion-weighted imaging (DWI) and chemical shift imaging (CSI).

METHODS

The Institutional Review Board approved this prospective study, and informed consent was obtained. IVIM MRI, DWI, and CSI at 1.5 T were performed in 25 patients with 12 acute compression fractures, 14 tuberculous spondylitis, and 18 malignant spinal tumours. The parameters of these techniques were assessed using the Kruskal-Wallis test. The diagnostic performance of the parameters was evaluated using receiver operating characteristic (ROC) analysis.

RESULTS

ADC, SIR, D_slow, D_fast, and f values of malignant tumours were significantly different from those of acute compression fracture (for all, p < 0.05). The mean D_slow and D_fast values of malignant spinal tumours had significant differences compared with those of tuberculous spondylitis (for all, p < 0.05). However, no significant differences were observed in any quantitative parameters between the acute compression fracture and the tuberculous spondylitis (p > 0.05). D_slow•f showed the highest AUC value of 0.980 (95%CI: 0.942-1.000) in differentiating acute compression fracture and malignant spinal tumours. D_slow showed the highest AUC value of 0.877 (95%CI: 0.713-0.966) in differentiating tuberculous spondylitis and malignant spinal tumours.

CONCLUSIONS

IVIM MR imaging may be helpful for differentiating malignant spinal tumours from acute vertebral compression fractures and tuberculous spondylitis.

MRI biomarkers in osseous tumors

Although radiography continues to play a critical role in osseous tumor assessment, there have been remarkable advances in cross-sectional imaging. MRI has taken a lead in this assessment due to high tissue contrast and spatial resolution, which are well suited for bone lesion assessment. More recently, although somewhat lagging other organ systems, quantitative parameters have shown promising potential as biomarkers for osseous tumors. Among these sequences are chemical shift imaging (CSI), apparent diffusion coefficient (ADC), and intravoxel incoherent motion (IVIM) from diffusion-weighted imaging (DWI), quantitative dynamic contrast enhanced (DCE)-MRI, and magnetic resonance spectroscopy (MRS). In this article, we review the background and recent roles of these quantitative MRI biomarkers for osseous tumors. Level of Evidence: 3 Technical Efficacy Stage: 3 J. MAGN. RESON. IMAGING 2019. J. Magn. Reson. Imaging 2019;50:702-718.

The META score for differentiating metastatic from osteoporotic vertebral fractures: an independent agreement assessment

BACKGROUND CONTEXT

Differentiating osteoporotic vertebral fractures (OVFs) from metastatic vertebral fractures (MVFs) is an important clinical challenge. A novel magnetic resonance imaging (MRI)-based score (the META score) was described, aiming to differentiate OVF from MVF. This score showed an almost perfect agreement by the group developing it, but an independent agreement evaluation is pending.

PURPOSE

We aimed to perform an independent inter- and intraobserver agreement evaluation of the META score and to test the score's capability of differentiating OVF from MVF.

STUDY DESIGN

This is an agreement study of the META score.

METHODS

Sixty-four patients with confirmed OVF or MVF were assessed by six independent evaluators (three spine surgeons and three fellowship-trained radiologists) using the META score. We used the intraclass correlation coefficient (ICC) to determine the overall inter-and intraobserver agreement, and the kappa statistic (κ) to express the agreement for each individual score criterion. The score accuracy was determined by calculating the area under the receiver operating characteristic curve. Finally, we used κ to evaluate the agreement among raters to determine whether the fracture was OVF or MVF.

RESULTS

The overall interobserver agreement was poor [ICC=0.10 (0.02-0.20)]; spine surgeons [ICC=0.75 (0.66-0.83)] had better agreement than radiologists did [ICC=0.05 (-0.08 to 0.21)]. The intraobserver agreement was poor [ICC=0.17 (0.01-0.32)]; both spine surgeons [ICC=0.21 (0.05-0.41)] and radiologists had a poor agreement [ICC=0.03 (-0.29 to 0.27)]. The agreement for each specific criterion varied from κ=0.24 to κ=0.60. The area under the receiver operating characteristic curve was 0.58 (0.64 for spine surgeons and 0.52 for radiologists, p<.01).

CONCLUSIONS

The interobserver agreement using the META score was adequate for spine surgeons but not for other potential users (radiologists); the intraobserver agreement was poor. Further studies are thus necessary before the use of this score is recommended.

The impact of magnetic resonance imaging in the diagnostic and classification process of osteoporotic vertebral fractures

INTRODUCTION

Standard radiographs are still considered as the gold standard for the early assessment of thoraco-lumbar osteoporotic vertebral fractures (OVFs), although several studies demonstrated superior accuracy of magnetic resonance imaging (MRI) in the diagnostic process of OVFs. The aim of this study was to quantify the misdiagnosis rate of OVFs and analyse the impact of MRI on early diagnosis and classification, compared to standard radiographs alone.

MATERIALS AND METHODS

A total of 173 patients were enrolled in this study. All participants were 55 years of age or older (60 years for men) and complained acute back pain with suspected thoracolumbar OVFs without history of high-energy trauma. Diagnosis of OVF was initially performed on standard radiographs obtained in the emergency room. Then, all the patients underwent MRI scan with short-tau inversion recovery (STIR) sequencing within 7 days. We compared the level and number of fractures identified on standard radiographs with the MRI scan results. The discordance between radiographic and MRI diagnosis was quantified. Fractures were classified according to AO Spine Classification.

RESULTS

Mean age of the study participant was 74.2 years (range 55-92). They were 100 males and 73 females. MRI modified initial diagnosis in 52% (90/173) of our patients: in 43.9% of patients MRI identified one or more new thoracolumbar fracture. In 14 cases (8.1%) MRI disproved the evidence of any thoracolumbar fracture, even those recognized at plain X-rays. Bone bruise was detected by MRI in 19 vertebral bodies in 8 patients (4.6%) at levels that were classified as unremarkable on X-ray alone. In addition, 63 patients (36.4%) presented a total of 93 old fractures. The classification of fracture pattern after MRI changed in 28.90% of the patients (changes mostly involved AO type A1 patterns).

CONCLUSIONS

Underdiagnosis of osteoporotic vertebral fractures is a common problem due to a lack of radiographic detection. Our results showed that the extensive use of MRI imaging allows better accuracy in the diagnostic process and in the classification assessment, compared to conventional radiographs. Further investigation should provide additional information about the impact of early MRI on treatment and management of elderly patients with suspected OVFs, including the decision to hospitalize or not, and how it could affect clinical outcome and social costs.

Does the META score evaluating osteoporotic and metastatic vertebral fractures have enough agreement to be used by orthopaedic surgeons with different levels of training?

PURPOSE

Differentiating osteoporotic vertebral fractures (OVF) from metastatic vertebral fractures (MVF) is difficult. A magnetic resonance imaging (MRI)-based score (META score) aiming to differentiate OVF and MVF was recently published; however, an independent agreement assessment is required before the score is used. We performed such independent agreement evaluation, including raters with different levels of training.

METHODS

Sixty-four patients with confirmed OVF or MVF were evaluated by six raters (three spine surgeons and three orthopaedic residents) using the META score. We used the intra-class correlation coefficient (ICC) to evaluate inter- and intra-observer agreement and the kappa statistic (κ) to determine the agreement for individual score criteria. We calculated the area under the receiver-operating characteristic curve (AUC) to establish the score accuracy.

RESULTS

The inter-observer agreement was poor [ICC = 0.22 (0.12-0.33)]; spine surgeons [ICC = 0.75 (0.66-0.83)] had better agreement than that of residents [ICC = 0.06 (- 0.07 to 0.23)]. The intra-observer agreement was poor [ICC = 0.15 (- 0.04 to 0.30)]; both spine surgeons [ICC = 0.21 (0.05-0.41)] and residents exhibited poor agreement [ICC = - 0.06 (- 0.40 to 0.20)]. The agreement for each specific criterion varied from κ = 0.24 to κ = 0.38. The AUC was 0.57 (0.64 for spine surgeons and 0.51 for residents, p < 0.01).

CONCLUSION

The inter-observer agreement using the META score was adequate for spine surgeons but not for residents; the intra-observer agreement was poor. These results do not support the standard use of the META score to differentiate OVF and MVF. These slides can be retrieved under Electronic Supplementary Material.

ACR Appropriateness Criteria® Osteoporosis and Bone Mineral Density

Osteoporosis is a considerable public health risk, with 50% of women and 20% of men >50 years of age experiencing fracture, with mortality rates of 20% within the first year. Dual x-ray absorptiometry (DXA) is the primary diagnostic modality by which to screen women >65 years of age and men >70 years of age for osteoporosis. In postmenopausal women <65 years of age with additional risk factors for fracture, DXA is recommended. Some patients with bone mineral density above the threshold for treatment may qualify for treatment on the basis of vertebral body fractures detected through a vertebral fracture assessment scan, a lateral spine equivalent generated from a commercial DXA machine. Quantitative CT is useful in patients with advanced degenerative bony changes in their spines. New technologies such as trabecular bone score represent an emerging role for qualitative assessment of bone in clinical practice. It is critical that both radiologists and referring providers consider osteoporosis in their patients, thereby reducing substantial morbidity, mortality, and cost to the health care system. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

High Signal in Bone Marrow on Diffusion-Weighted Imaging of Female Pelvis: Correlation With Anemia and Fibroid-Associated Symptoms

BACKGROUND

The diffusion-weighted imaging (DWI) signals of the female pelvic bone marrow show great variability and are usually high in female patients with fibroid-associated symptoms and anemia.

PURPOSE

To ascertain clinical factors contributing to high signal intensity in the bone marrow of the female pelvis on DWI.

STUDY TYPE

Retrospective case-control study.

SUBJECTS

A single-institution review of 221 female patients underwent a pelvic magnetic resonance study from December 2012 to July 2014.

FIELD STRENGTH/SEQUENCE

1.5T/DWI (b = 0 and 1000) and apparent diffusion coefficient (ADC).

ASSESSMENT

The ADC of pelvic bone marrow and the muscle-normalized signal intensity (SI) on DWI (mnDWI) were measured. A brightness grading scale ranging from 0 to 4 was used for pelvic bone assessment. Clinical factors, namely, age, the lowest hemoglobin level in the last 6 months, the presence of large uterine fibroids, and/or adenomyosis and fibroid-associated symptoms were recorded.

STATISTICAL TESTS

The relationships between the brightness grade and clinical factors were evaluated through multinomial logistic regression, and correlations of mnDWI and the ADC with the clinical factors were analyzed through the Kruskal-Wallis test, Jonckheere's trend test, and the Mann-Whitney U-test with Bonferroni correction.

RESULTS

Age and the hemoglobin level were inversely associated with the bone marrow brightness grade on DWI (both P < 0.05), whereas the presence of fibroid-associated symptoms showed a positive association (P = 0.028). The ADC and mnDWI in women younger than 50 years were significantly higher than those in older women (both P < 0.0001). The ADC had no significant correlation with anemia (P = 0.511), whereas mnDWI increased as the severity of anemia increased (P = 0.00154).

DATA CONCLUSION

Our study showed an association of high DWI SI of pelvic bone marrow with anemia in premenopausal women.

LEVEL OF EVIDENCE

4 Technical Efficacy Stage 3 J. Magn. Reson. Imaging 2018;48:1024-1033.

Vertebral Imaging in the Diagnosis of Osteoporosis: a Clinician's Perspective

PURPOSE OF REVIEW

Vertebral fractures are the most common osteoporotic fracture and result in functional decline and excess mortality. Dual-energy x-ray absorptiometry (DXA) is the gold standard for the diagnosis of osteoporosis to identify patients at risk for fragility fractures; however, advances in imaging have expanded the role of computed tomography (CT) and magnetic resonance imaging (MRI) in evaluating bone health.

RECENT FINDINGS

The utility of CT and MRI in the assessment of bone density is starting to gain traction, particularly when used opportunistically. DXA, conventional radiography, CT, and MRI can all be used to assess for vertebral fractures, and MRI can determine the acuity of fractures. Finally, advances in imaging allow for non-invasive assessment of measures of bone quality, including microarchitecture, bone strength, and bone turnover, to help identify and treat at-risk patients prior to sustaining a vertebral fracture. CT and MRI techniques remain primarily research tools to assess metabolic bone dysfunction, while use of DXA can be clinically expanded beyond measurement of bone density to assess for vertebral fractures and bone architecture to improve fracture risk assessment and guide treatment.

Diffusion imaging of the vertebral bone marrow

Diffusion-weighted MRI (DWI) of the vertebral bone marrow is a clinically important tool for the characterization of bone-marrow pathologies and, in particular, for the differentiation of benign (osteoporotic) and malignant vertebral compression fractures. DWI of the vertebral bone marrow is, however, complicated by some unique MR and tissue properties of vertebral bone marrow. Due to both the spongy microstructure of the trabecular bone and the proximity of the lungs, soft tissue, or large vessels, substantial magnetic susceptibility variations occur, which severely reduce the magnetic field homogeneity as well as the transverse relaxation time T^*₂ , and thus complicate MRI in particular with echoplanar imaging (EPI) techniques. Therefore, alternative diffusion-weighting pulse sequence types such as single-shot fast-spin-echo sequences or segmented EPI techniques became important alternatives for quantitative DWI of the vertebral bone marrow. This review first describes pulse sequence types that are particularly important for DWI of the vertebral bone marrow. Then, data from 24 studies that made diffusion measurements of normal vertebral bone marrow are reviewed; summarizing all results, the apparent diffusion coefficient (ADC) of normal vertebral bone marrow is typically found to be between 0.2 and 0.6 × 10^-3  mm² /s. Finally, DWI of vertebral compression fractures is discussed. Numerous studies demonstrate significantly greater ADCs in osteoporotic fractures (typically between 1.2 and 2.0 × 10^-3  mm² /s) than in malignant fractures or lesions (typically 0.7-1.3 × 10^-3  mm² /s). Alternatively, several studies used the (qualitative) image contrast of diffusion-weighted acquisitions for differentiation of lesion etiology: a very good lesion differentiation can be achieved, particularly with diffusion-weighted steady-state free precession sequences, which depict malignant lesions as hyperintense relative to normal-appearing vertebral bone marrow, in contrast to hypointense or isointense osteoporotic lesions. Copyright © 2015 John Wiley & Sons, Ltd.

Evaluation of Diffusion-weighted MR Imaging as a Technique for Detecting Bone Marrow Edema in Patients with Osteitis Pubis

Purpose:

Our aims were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bone marrow edema (BME) and explore the apparent diffusion coefficient (ADC) alterations in patients with osteitis pubis (OP).

Materials and Methods:

42 consecutive patients clinically suspected to have athletic pubalgia and 31 control subjects were enrolled in the study. All subjects underwent diagnostic focused magnetic resonance imaging (MRI) and DWI at b values of 0 and 600 s/mm². Two radiologists reviewed the images for the presence of active OP. The presence of subchondral BME and contrast enhancement were considered to indicate active OP. ADC values were measured from public bodies of both groups. DWI results were correlated with routine MRI findings. Receiver-operating-characteristic curves were formed. Cut-off values for ADC, sensitivity and specificity values were measured.

Results:

36/42 (85%) of the cases had BME/enhancement on routine MRIs and identified as active OP. ADC measurements of the patients were greater than the controls (P < 0.05). For the optimal cut-off values DWI showed sensitivity and specificity values of 97.3%, and 90.3%, for the right, and 97.1%, and 96.7% for the left side, respectively (Area under the curve 0.965 and 0.973). Intra-and inter-rater reliability for readers were substantial-perfect for all sessions.

Conclusion:

DWI is fast, accurate, and highly reproducible technique for the detection of BME in patients with active OP. It allows distinct bone marrow contrast without the use of gadolinium contrast, increases visual perception of active lesions, gives objective information by quantifying the diffusion coefficients, thus increase diagnostic confidence. We suggest the use of DWI as a cost-effective adjunctive tool for the diagnosis of active OP particularly in early cases and inconclusive diagnostic MRI. Future studies are necessary to determine the utility of DWI to evaluate severity of the disease and treatment response before returning athletes to play.

Evaluation of Apparent Diffusion Coefficient Values in Spinal Tuberculosis by MRI

INTRODUCTION

Spinal tuberculosis presents a radiological challenge in many cases when it presents with atypical pattern of involvement and has to be distinguished from various differentials, which include metastases. In such cases Diffusion Weighted Imaging (DWI) with Apparent Diffusion Co-efficient (ADC) value may play a role in reaching towards a conclusion, thereby preventing unnecessary biopsy in such patients.

AIM

Measurement of mean ADC values in tubercular vertebrae and associated collection.

MATERIALS AND METHODS

The study was comprised of 55 patients and was conducted on 3.0 TESLA Siemens machine Magnetom Verio. Patients either known to have tuberculosis or those with classic tuberculous findings were included in the study. All these patients were followed up for post-treatment confirmation and ADC value. All the patients underwent routine MRI along with DW-MRI sequence, ADC values and FNAC/ Biopsy if required. The ADC values were calculated from the involved vertebral bodies and surrounding soft tissue and also from normal vertebrae preferably from one above and below the affected vertebrae to establish ADC of normal vertebrae, which was helpful in treatment response in patients with antitubercular therapy. At least six ADC value was taken from affected vertebrae and soft tissue.

RESULTS

The mean ADC value of tubercular vertebrae was found out to be 1.47 ± 0.25 x 10(-3) mm(2)/sec, of adjacent soft tissue collection (abscess) was 1.94 ± 0.30 x 10(-3) mm(2)/sec and normal vertebrae was 0.48 ± 0.16 x 10(-3) mm(2)/sec. ADC value of post treated vertebrae decreased and complete resolution showed ADC near normal vertebrae.

CONCLUSION

Normal range of the ADC values in spinal tuberculosis and associated paravertebral collection may be helpful in the differentiation of spinal tuberculosis from lesions with spinal involvement which are not proven to be tuberculosis and who did not have the classical appearance of either tuberculosis or metastasis. But there exists a zone of overlap of ADC values in metastatic and tubercular vertebrae, which can lead to false negative results. Therefore, in overlap cases there should be correlation with clinical history, other related investigations or biopsy.

Diffusion-weighted magnetic resonance imaging in differentiating acute infectious spondylitis from degenerative Modic type 1 change; the role of b-value, apparent diffusion coefficient, claw sign and amorphous increased signal

OBJECTIVE

To examine the effect of using different b-values on the utility of diffusion-weighted (DW) MRI in differentiating acute infectious spondylitis from Modic type 1 and the discriminative accuracy of related apparent diffusion coefficient (ADC), claw-sign and amorphous increased signal.

METHODS

43 patients with equivocal diagnosis of acute infectious spondylitis/Modic type 1 by using MR images were prospectively studied. The discriminative accuracy of DW MRI using three b-values of 50, 400, 800 s mm(-2), ADC, claw sign and amorphous increased signal was examined.

RESULTS

DW MRI differentiated infectious spondylitis from Modic type 1 change most accurately when a b-value of 800 s mm(-2) was chosen [sensitivity, 91.7%; specificity, 96.8%; positive-predictive value (PPV), 91.7%; negative-predictive value (NPV), 96.8%; and accuracy, 95.3%]. The optimal cut-off ADC value was 1.52 × 10(-3) mm(2) s(-1) (sensitivity, 91.7%; specificity, 100%; PPV, 100%; NPV, 96.9%; and accuracy, 97.7%). Best visualized at a b-value of 50 s mm(-2), claw sign (for degeneration) and amorphous increased signal (for infection) were 100% accurate.

CONCLUSION

Should DW MRI be used in differentiating acute infectious spondylitis from degeneration, large b-values are required. With low b-values, however, claw sign and amorphous increased signal are very accurate in this regard.

ADVANCES IN KNOWLEDGE

DW MRI using large b-values could be used in differentiating acute infectious spondylitis from Modic type I.

Computed Tomography and Magnetic Resonance Imaging in the Differentiation of Osteoporotic Fractures From Neoplastic Metastatic Fractures

Determining whether a low-intensity vertebral fracture in an older person, particularly one with a history of cancer, is due to osteoporosis (OP) or is the result of a metastasis, is a not infrequent clinical problem that has important prognostic and therapeutic implications. The 2 types of fracture are usually indistinguishable on plain radiographs and require higher order imaging for diagnosis. Magnetic resonance imaging is the modality of choice because of its unique ability to depict the bone marrow, which becomes transiently edematous in an acute OP fracture. Preservation of at least part of the normal marrow signal, the visualization of a fracture line parallel to the end plates, the presence of an intravertebral cleft, lack of pedicle involvement, and no extra-osseous mass all favor a benign OP fracture. Absence of the preceding signs, particularly if there is complete replacement of the normal bone marrow and a convex posterior contour of the vertebral body, favors a fracture of malignant origin. Non-routine magnetic resonance sequences using diffusion-weighted imaging and/or chemical shift imaging may be helpful in difficult cases.

Diffusion-weighted imaging in musculoskeletal radiology-clinical applications and future directions

Diffusion-weighted imaging (DWI) is an established diagnostic tool with regards to the central nervous system (CNS) and research into its application in the musculoskeletal system has been growing. It has been shown that DWI has utility in differentiating vertebral compression fractures from malignant ones, assessing partial and complete tears of the anterior cruciate ligament (ACL), monitoring tumor response to therapy, and characterization of soft-tissue and bone tumors. DWI is however less useful in differentiating malignant vs. infectious processes. As of yet, no definitive qualitative or quantitative properties have been established due to reasons ranging from variability in acquisition protocols to overlapping imaging characteristics. Even with these limitations, DWI can still provide clinically useful information, increasing diagnostic accuracy and improving patient management when magnetic resonance imaging (MRI) findings are inconclusive. The purpose of this article is to summarize recent research into DWI applications in the musculoskeletal system.

Standard-b-value vs low-b-value DWI for differentiation of benign and malignant vertebral fractures: a meta-analysis

OBJECTIVE

To determine the comparative diagnostic performance of standard-b-value (≥500 mm(2)) vs low-b-value (<500s mm(-2)) diffusion-weighted imaging (DWI) for discriminating malignant from benign vertebral compression fractures.

METHODS

12 studies with a total of 350 malignant and 312 benign vertebral fractures were included.

RESULTS

The apparent diffusion coefficient (ADC) value of benign vertebral compression fractures was lower than that of malignant vertebral compression fractures (SMD = 1.81, 95% CI 0.98 to 2.64 Z = 4.27, p < 0.05). ADC value difference was more pronounced in the group of low-b-value DWI (SMD = 2.31, 95% CI 1.02 to 3.60 Z = 3.51, p < 0.05) than in the group of standard-b-value DWI (SMD = 1.38, 95% CI 0.18 to 2.59 Z = 2.25, p < 0.05). Ethnicity stratified analysis demonstrated higher ADC values in benign vertebral compression fractures in comparison to malignant tissues in both the Asian and Caucasian subgroups (Asians: SMD = 2.400, 95%CI 1.45 to approximately 3.35, p<0.05; Caucasians: SMD = 0.592, 95 % CI -0.848 to approximately 2.032, p < 0.05). And the ADC value difference was more pronounced in the Asian subgroup.

CONCLUSION

ADC value appears to be a reliable method to differentiate benign from malignant fractures. Low-b-value DWI was more a valuable parameter than standard-b-value DWI for discriminating malignant from benign vertebral compression fractures. And the diffusion characteristics of the benign vertebral fractures such as osteoporosis, trauma and infection have rarely been investigated separately.

ADVANCES IN KNOWLEDGE

The use of low-b-value DWI for differentiation of benign and malignant vertebral fractures is recommended.

Diffusion-weighted magnetic resonance imaging of femoral head osteonecrosis in two groups of patients: Legg-Perthes-Calve and Avascular necrosis

INTRODUCTION

The aim of this prospective study was to evaluate the value of diffusion-weighted magnetic resonance imaging (DW-MRI) in patients with osteonecrosis. Patients were divided into two subgroups as avascular necrosis (AVN) of femoral head for adult group and Legg-Calvé-Perthes (LCP) patients for children.

PATIENTS AND METHODS

Seventeen patients with femoral head AVN (mean age 42.3 years) and 17 patients with LCP (mean age 8.2 years) were included in this study. Diagnosis confirmed with clinical and other imaging procedures among the patients complaining hip pain. DW images were obtained using the single-shot echo planar sequence and had b values of 0, 500, 1000 s/mm(2). The apparent diffusion coefficient (ADC) values were measured from ADC maps in epiphysis of patients with AVN, both from metaphysis and epiphysis in patients with LCP, respectively. Mann-Whitney U test was used to compare ADC values.

RESULTS

The mean ADC value of femoral heads (1.285 ± 0.204 × 10(-3) mm(2)/s) was increased in patients with AVN when compared to normal bone tissue (0.209 ± 0.214 × 10(-3) mm(2)/s) (p < 0.01). The mean ADC values (×10(-3) mm(2)/s) of both metaphysis (0.852 ± 0.293) and epiphysis (0.843 ± 0.332) were also increased in patients with LCP and differences were statistically significant (p < 0.01).

CONCLUSIONS

As a result, osteonecrosis shows increased ADC values. But it is a controversial concept that DWI offers a valuable data to conventional MRI or not. However, as there are report states, there is a correlation between the stage of the disease with ADC values in the LCP disease. DWI is a fast, without-contrast administration technique and provides quantitative values additional to conventional MR techniques; we believe DWI may play an additional assistance to the diagnosis and treatment for LCP patients. Multicentric larger group studies may provide additional data to this issue.

META: an MRI-based scoring system differentiating metastatic from osteoporotic vertebral fractures

BACKGROUND CONTEXT

Magnetic resonance imaging (MRI) is useful for the differential diagnosis of osteoporotic vertebral fractures (OVFs) and metastatic vertebral fractures (MVFs), but no single finding is absolutely conclusive.

PURPOSE

The purpose of the present study was to create a scoring system to facilitate the correct diagnosis of MVFs by integrating several MRI findings.

STUDY DESIGN

This is a retrospective and single-center observational study that attempts to create a diagnostic scoring system by discriminant analysis.

PATIENTS SAMPLE

We included 100 OVFs and 100 MVFs in thoracolumbar vertebrae of which MR images were obtained within 60 days from the suspected time of fractures.

OUTCOME MEASURES

The sensitivity and specificity of known important MRI findings were assessed, and the classification accuracy of the scoring system was investigated.

METHODS

Seven MRI findings of these fractures were analyzed to evaluate their sensitivity and specificity. Using these findings as variables, discriminant analysis was performed in 140 fractures as a training set, and the classification accuracy was calculated in the remaining 60 fractures as a test set. Additionally, the images of these 60 fractures were reviewed by another blinded reviewer to investigate the interobserver reliability of each finding.

RESULTS

All findings had high specificity with low-to-moderate sensitivity. Eight variables were selected in the final discriminant function. A simpler scoring system (MRI Evaluation Totalizing Assessment [META]) was created by approximating the coefficients and the constant term by integral numbers. The classification accuracy was calculated to be 96.6% in the test set. The interobserver reliability of the key findings varied, but the final discrimination conducted by META had the high agreement between the two reviewers (κ=0.93).

CONCLUSIONS

This novel scoring system, META, could prove to be a useful tool for the differential diagnosis of OVFs and MVFs. It is simple and physician friendly, yet highly accurate.

[Differentiation between acute osteoporotic and metastatic vertebral body fractures by imaging]

OBJECTIVES

This article discusses the morphological criteria for the differentiation between acute osteoporotic and metastatic vertebral body fractures and new imaging methods, such as diffusion-weighted and chemical shift magnetic resonance imaging (MRI) are presented.

BACKGROUND

The differential diagnostics of osteoporotic and metastatic vertebral body fractures can be difficult in some cases. Both entities normally occur without adequate trauma and predominantly in elderly patients.

IMAGING

Conventional X-ray examination is the initial imaging method of choice but is not able to reliably differentiate between the osteoporotic or metastatic etiology of a fracture. Computed tomography (CT) clearly depicts osseous destruction in metastatic fractures but lacks specificity. Magnetic resonance imaging (MRI) shows a higher sensitivity and specificity in differentiating osteoporotic and metastatic fractures.

DIFFERENTIAL DIAGNOSTICS

The combination CT and MRI allows an accurate diagnosis with respect to an osteoprorotic or metastatic etiology in most of cases but bone marrow edema in acute fractures sometimes leads to ambiguous results and differential diagnostic problems.

Quantitative evaluation of benign and malignant vertebral fractures with diffusion-weighted MRI: what is the optimum combination of b values for ADC-based lesion differentiation with the single-shot turbo spin-echo sequence?

OBJECTIVE

The purpose of our study was to determine the optimum combination of b values for calculating the apparent diffusion coefficient (ADC) using a diffusion-weighted (DW) single-shot turbo spin-echo (TSE) sequence in the differentiation between acute benign and malignant vertebral body fractures.

SUBJECTS AND METHODS

Twenty-six patients with osteoporotic (mean age, 69 years; range, 31.5-86.2 years) and 20 patients with malignant vertebral fractures (mean age, 63.4 years; range, 24.7-86.4 years) were studied. T1-weighted, STIR, and T2-weighted sequences were acquired at 1.5 T. A DW single-shot TSE sequence at different b values (100, 250, 400, and 600 s/mm(2)) was applied. On the DW images for each evaluated fracture, an ROI was manually adapted to the area of hyperintense signal intensity on STIR-hypointense signal on T1-weighted images. For each ROI, nine different combinations of two, three, and four b values were used to calculate the ADC using a least-squares algorithm. The Student t test and Mann-Whitney U test were used to determine significant differences between benign and malignant fractures. An ROC analysis and the Youden index were used to determine cutoff values for assessment of the highest sensitivity and specificity for the different ADC values. The positive (PPV) and negative predictive values (NPV) were also determined.

RESULTS

All calculated ADCs (except the combination of b = 400 s/mm(2) and b = 600 s/mm(2)) showed statistically significant differences between benign and malignant vertebral body fractures, with benign fractures having higher ADCs than malignant ones. The use of higher b values resulted in lower ADCs than those calculated with low b values. The highest AUC (0.85) showed the ADCs calculated with b = 100 and 400 s/mm(2), and the second highest AUC (0.829) showed the ADCs calculated with b = 100, 250, and 400 s/mm(2). The Youden index with equal weight given to sensitivity and specificity suggests use of an ADC calculated with b = 100, 250, and 400 s/mm(2) (cutoff ADC, < 1.7 × 10(-3) mm(2)/s) to best diagnose malignancy (sensitivity, 85%; specificity, 84.6%; PPV, 81.0%; NPV, 88.0%).

CONCLUSION

ADCs calculated with a combination of low to intermediate b values (b = 100, 250, and 400 s/mm(2)) provide the best diagnostic performance of a DW single-shot TSE sequence to differentiate acute benign and malignant vertebral body fractures.

Bone marrow lesions: A systematic diagnostic approach

Bone marrow lesions on magnetic resonance (MR) imaging are common and may be seen with various pathologies. The authors outline a systematic diagnostic approach with proposed categorization of various etiologies of bone marrow lesions. Utilization of typical imaging features on conventional MR imaging techniques and other problem-solving techniques, such as chemical shift imaging and diffusion-weighted imaging (DWI), to achieve accurate final diagnosis has been highlighted.

ACR appropriateness criteria management of vertebral compression fractures

This is an updated review of management of vertebral compression fracture for both benign osteoporotic and malignant causes. Vertebral compression fracture radiologic imaging evaluation is discussed. A literature review is provided of current indications for vertebral augmentation with percutaneous vertebroplasty and kyphoplasty as well as medical management. Limitations and potential benefits of these procedures are discussed. Variant tables describing various clinical situations are also provided to assist in determining appropriate use of these treatments for patient care. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to formulate recommendations for imaging or treatment.

Therapy monitoring of skeletal metastases with whole-body diffusion MRI

Current methods of assessing tumor response at skeletal sites with metastatic disease use a combination of imaging tests, serum and urine biochemical markers, and symptoms assessment. These methods do not always enable the positive assessment of therapeutic benefit to be made but instead provide an evaluation of progression, which then guides therapy decisions in the clinic. Functional imaging techniques such as whole-body diffusion magnetic resonance imaging (MRI) when combined with anatomic imaging and other emerging "wet" biomarkers can improve the classification of therapy response in patients with metastatic bone disease. A range of imaging findings can be seen in the clinic depending on the type of therapy and duration of treatment. Successful response to systemic therapy is usually depicted by reductions in signal intensity accompanied by apparent diffusion coefficient (ADC) increases. Rarer patterns of successful treatment include no changes in signal intensity accompanying increases in ADC values (T2 shine-through pattern) or reductions in signal intensity without ADC value changes. Progressive disease results in increases in extent/intensity of disease on high b-value images with variable ADC changes. Diffusion MRI therapy response criteria need to be developed and tested in prospective studies in order to address current, unmet clinical and pharmaceutical needs for reliable measures of tumor response in metastatic bone disease.

Differentiation of acute osteoporotic and malignant compression fractures of the spine: use of additive qualitative and quantitative axial diffusion-weighted MR imaging to conventional MR imaging at 3.0 T

PURPOSE

To retrospectively determine the value of adding qualitative and quantitative axial diffusion-weighted (DW) imaging to standard spine magnetic resonance (MR) imaging to differentiate between acute osteoporotic and malignant compression fractures at 3.0 T.

MATERIALS AND METHODS

The institutional ethics committee approved this retrospective study and waived the requirement to obtain informed consent. The authors retrospectively analyzed 3.0-T MR images, including DW images (b values: 0, 800, and 1400 sec/mm(2)), in 62 patients with acute compression fractures. Three radiologists independently interpreted MR images for the presence of malignancy by using conventional MR images alone and in combination with axial DW images with qualitative and quantitative analysis. Apparent diffusion coefficients (ADCs) were measured within solid portion with careful use of a small region of interest (ROI). The Mann-Whitney U test was performed.

RESULTS

There were 30 malignant and 32 acute osteoporotic compression fractures. At qualitative analysis, hyperintensity relative to spinal cord was more frequent in malignant compression fractures than in acute osteoporotic compression fractures (87% vs 22%, respectively; P < .001). Median ADCs of malignant fractures were significantly lower than those of benign fractures (P < .001). With conventional MR imaging alone, sensitivity, specificity, and accuracy were 100%, 94%, and 97%, respectively, for reader 1; 97%, 78%, and 87% for reader 2; and 100%, 84%, and 92% for reader 3. With conventional and DW MR imaging combined, sensitivity, specificity, and accuracy were 100%, 97%, and 98% for all three readers. The addition of DW imaging led to correct changes in diagnosis: Reader 1 improved by 1.6% (one of 62 fractures), reader 2 improved by 11% (seven of 62 fractures), and reader 3 improved by 6.5% (four of 62 fractures).

CONCLUSION

The addition of axial DW imaging to a conventional MR imaging protocol improved diagnostic accuracy in the differentiation of acute osteoporotic from malignant compression fractures by measuring ADCs in the solid portion with careful use of a small ROI.