Diagnostic performance of MRI in differentiating metastatic from acute osteoporotic compression fractures of the spine

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1 Diagnostic performance of MRI in differentiating metastatic from acute osteoporotic compression fractures of the spine Poster No.: C-1399 Congress: ECR 2013 Type: Scientific Exhibit Authors: J. Martel, A. Bueno, M. Nogueras, M. Barxias, E. Pérez; Alcorcón/ ES Keywords: Musculoskeletal spine, Oncology, MR, MR-Diffusion/Perfusion, Diagnostic procedure, Comparative studies, Metastases, Osteoporosis DOI: /ecr2013/C-1399 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 17

2 Purpose Differentiating benign from malignant vertebral marrow processes is a frequent and sometimes difficult problem, especially distinction between metastatic and acute osteoporotic compression fractures. Morphologic criteria may accurately predict benign from malignant fractures of the spine in up to 90% of cases, however it is not perfect and conventional MR sequences are nonspecific. Our purpose is to determine the contribution of the new sequences(diffusion, ADC values and in-phase/out-of-phase sequences) in differentiating between malignant and benign bone marrow lesions. Images for this section: Page 2 of 17

3 Fig. 1 Page 3 of 17

4 Methods and Materials Patient selection A total of 85 consecutive patients included 60 women and 25 men, ranging in age from 33 to 90 years old (mean 67) were prospectively studied. The patients presented vertebral collapse and/or altered signal intensity in one or more vertebral bodies on conventional MR sequences. A total of 213 vertebral bodies were analysed. From each patient, one normal vertebral body and one, two or three pathologic verterbal bodies were recorded. 26 patients had an history of a known primary tumor The different pathologies are showed in the table: Fig. 2: Table show diagnosis distribution Page 4 of 17

5 References: Diagnóstico por Imagen, Hospital Universitario Fundación Alcorcón Alcorcón/ES MR Images All MR studies were performed by using a 1.5 T unit (Signa Excite; GE Medycal Systems). The following pulse sequences were used for all patients: axial and sagittal T1-weighted spin-echo imaging; axial and sagittal T2-weighted fast spin-echo imaging; sagittal STIR imaging; sagittal in-phase and out-of-phase imaging and sagittal diffusion-weighted sequences (Echo planar imaging, b=400). Postprocessing and pathologic analysis All the images of each patient were interpreted in consensus by two radiologists. The signal intensity of the vertebral bodies were qualitatively evaluated on T1-weighted and T2-weighted images, STIR images and diffusion-weight images and were described as hypointense, isointense or hyperintense signal. The signal intensity values for in-phased an out-of-phase images were measured for each vertebral body or lesion. A cut-off of 0.8 was chosen with <0.8 defined as benign, defined as indeterminated an >1 defined as malignant. A computation of the bone marrow signal intensity ratio (SIR) measured on out-of-phase/ in-phase images was made. Apparent diffusion coefficent (ADC) values were also determined. Statistical analysis Sensibility, specificity and accuracy were estimated with 95% confidence interval. To evaluate discriminant capacity of ratio out-of-phase/in-phase and ADC values, area under ROC curve was estimated and the cut point with maximum sensibility and specificity were calculated. Results Page 5 of 17

6 Summary values of sensitivity, specificity and accuracy for changes in signal intensity and ratio (SIR) values, and ADC values for the diagnosis of metastasis are represented in the next table Fig. 3 References: Diagnóstico por Imagen, Hospital Universitario Fundación Alcorcón Alcorcón/ES The area under the curve shows the signal intentisity ratio (SIR) having better discriminant capacity than ADC values. Page 6 of 17

7 Fig. 4 References: Diagnóstico por Imagen, Hospital Universitario Fundación Alcorcón Alcorcón/ES A lesion in a vertebral body that shows hypointensity in T1-wi, hyperintensity on STIR and T2-wi, and a signal intensity ratio >0.8 has a sensitivity of 97.2%, specificity of 90% and accuracy of 91.2% respect the diagnosis of a malignat lesion. We summarize our results in the normal vertebra and different lesions: Normal vertebral bodies Page 7 of 17

8 All cases showed normal signal intensity in vertebral marrow on T1-weighted images, T2-weighted, diffusion-weighted or STIR images. Signal Intensity Ratio (SIR) were < ADC values were less than 0.6x10 mm /s Haemangioma Hemangiomas had high intensity on both T1- and T2-weighted images Fig. 5 on page 10. Three cases appeared as hypointense on T1-weighted images and hypo- or hyperintese on T2-weighted images (these cases were biopsied). Diffusion-weighted images were normal in all cases but three of them with a subtle high signal. SIR were > 0.8 in 50% of patients. Fig. 6 on page ADC values were > than 1x10 mm /s but < than 1.5x10 mm /s Fig. 7 on page 10 Espondilosis (endplate degeneration) All cases showed normal signal intensity on T1-weighted images, T2-weighted, diffusionweighted or STIR images, or showed typical findings of Modic lesions. SIR were < ADC values were less than 0.6x10 mm /s Osteoporotic fracture (chronic) Chronic osteoporotic fractures had low intensity on T1-weighted images. Signal on T2weighted images were variable. Page 8 of 17

9 STIR and diffusion-weighted images were normal. Fig. 8 on page 11 SIR were < ADC values were < than 1x10 mm /s Fig. 9 on page 11 Osteoporotic fracture (acute) Acute osteoporotic fractures had low intensity on T1-weighted images. Signal on T2weighted images were variable. STIR showed high signal and diffusion-weighted images showed subtle high signal. SIR were variable, almost 50% > 0.8 Fig. 10 on page ADC values were > than 1.5 x10 mm /s Fig. 11 on page 13 Metastasis Metastatic fractures had a low intensity on T1-weighted images. Signal on T2-weighted images were variable. STIR and diffusion-weighted images showed high signal. SIR > 0.8 in all cases ADC values were >than 1x10 mm /s but < 1.5x10 mm /s Fig. 12 on page 13 Miscellany Spondylodiscitis, Schmörl s nodes (Fig. 13 on page 14 Fig. 14 on page 15), calcified intraspongious disk herniation, and other entitys may simulate malignant lesion, but we have few cases to get statistical analysis. Page 9 of 17

10 Images for this section: Fig. 5: T2-(left) and T1-weighted images (right) show a hyperintense lesion in the vertebral body. Fig. 6: Out-of-phase (left) and in-phase MR images of the same patient. In this case, SIR was % of hemangiomas had SIR>0.8 Page 10 of 17

11 Fig. 7: Difussion-weighted image (left) shows a very subtle hyperintensity in th vertebral body. ADC value (right) was 1.35 Fig. 8: Chronic fracture: T1-weighted, STIR and T2-weighted images. Lesion is hypointense in all sequences Page 11 of 17

12 Fig. 9: From left-to-right: out-of-phase and in-phase images. Lesion has a SIR of DW-EPI is normal and ADC values is 1.55 Fig. 10: Patient with breast cancer. T1-weighted image (left) shows a hypo intense lesion en L3 and another lesion in T1. In-phase and out-of-phase images (right). SIR is 0.52 Page 12 of 17

13 Fig. 11: 63-year-old woman with acute osteoporotic fracture. DW-EPI shows hyperintense signal at b value of 400 s/mm2 Page 13 of 17

14 Fig. 12: 78-year-old man with lung cancer. T2-weighted image show an acute fracture in T12 and a hypointense lesion in L3. DW-EPI show hyperintense signal in both lesion. Biopsy was performed to confirm malignant fracture of T12 vertebral body. Page 14 of 17

15 Fig. 13: T2-, T1-weighted images; STIR and T1-weighted after gadolinium administration. A Schmörl s node is seen in the superior endplate. Fig. 14: Out-of-phase and in-phase images (left): SIR is 1.2 DW-EPI shows hyperintense lesion in the vertebral body. ADC is 1.5. Page 15 of 17

16 Conclusion MRI is crucial in the diagnosis and management of patients with vertebral lesions. The radiologist should know the semiology to make the differential diagnosis between osteoporotic fracture and metastasis, and the role of the new sequences. Distinction between metastatic and acute osteoporotic compression fractures could be made on the basis of these MR imaging findings in metastasis: Typically well marginated, hypointense on T1-weighted images and hyperintense on T2-weighted images A convex posterior border of the vertebral body Abnormal signal intensity of the pedicle or posterior element An epidural mass An encasing epidural mass A focal paraspinal mass Other spinal metastasis But acute osteoportic fractures (and some other lesions) may mimic the signal alterations observed in vertebra metastases. We have studied the utility of signal characteristics on T1-weighted images, STIR and diffusion-weighted images, out-of-phase/in-phase signal intensity ratio and apparent diffusion coefficent values to differentiate benign from malignant processes in the spine. MR imaging findings suggestive of malignat lesion were as follows: Hypointensity on T1-weighted images Hyperintensity on STIR Hyperintensity on diffsuion-weighted images Signal intensity ratio >0.8. Morphological aspects combined with all these findings are strongly suggestive of malignant etiology. ADC values play little role in distinguishing between malignat from benign lesions although increased values (>1.5) are more specific for acute osteoporotic fractures. Page 16 of 17

17 In our experience, the diagnosis of benign versus malignat lesion in a vertebral body is possible in more than 97% of patients. Biopsy is needed in certain selected cases. References Balliu E, Vilanova JC, Peláez I,et al. Diagnostic value of apparent diffusion coefficients to differentiate benign from malignant vertebral bone marrow lesions. European Journal of Radiology 2009; 69: Baur A, Stabler A, Brunning R,et al. Diffusion-weighted MR imaging of bone marrow: differentiation of benign versus pathologic compression fractures. Radiology 1998;207: Erly WK, Oh ES, Outwater EK. The Utility of In-Phase/Opposed-Phase Imaging in Differentiating Malignancy from Acute Benign Compression Fractures of the Spine. AJNR Am J Neuroradiol 2006; 27: Jung et al. Discriminationination of Metastatic from Acute Osteoporotic Compression Spinal Fractures with MR Imaging. RadioGraphics 2003; 23: Karchevsky Can diffusion-weighted imaging be used to differentiate benign from pathologic fractures? A meta-analysis. Skeletal Radiol 2008; 37: Khoo MMY et al. Diffsuion-weighted imaging (DWI) in musculoskeletal MRI: a critical review. Skeletal Radiol 2011; 40: Oztekin et al. SSH-EPI diffusion-weighted MR imaging of the spine with low b values: is it useful in differentiating malignant metastatic tumor infiltration from benign fracture edema?. Skeletal Radiol 2009; 38: Yuh WT, Zachar CK, Barloon TJ, et al. Vertebral compression fractures: distinction between benign and malignat causes with MR imaging. Radiology 1989;172: Zajick DC Jr, Morrison WB, Schweitzer ME,et al. Benign and malignant processes:normal Values and Differentiation with Chemical Shift MR Imaging in Vertebral marrow. Radiology 2005; 237: Personal Information Page 17 of 17