Purpose
Traditional metastatic spine surveys employ a combination of T1, T2, STIR and if there are no contraindications, contrast enhanced sequences. Despite thismulti-modalassessment, studies are often difficult to interpret. This is particularly true in elderly patients with heterogeneous bone marrow composition/signal and when lesions occur in such locations as the pedicles, articulating facets and vertebral endplates where degenerative changes and Schmorl nodes complicate detection and characterization.From a microscopic perspective, metastases are composed of densely packed cells that impede water diffusivity in surrounding bone matrix. On the...
Methods and Materials
We retrospectively reviewed spinal surveys performed at our institution from June to Novermber 2009. All patients were known to have spinal metastases at the time of imaging by prior pathologic confirmation. All spinal surveys employed sagittal T1, STIR and T2 weighted sequences. A contrast enhanced sequence was obtained if there were no contraindications to gadolinium based agents. In addition, an echo-planar (EPI) diffusion weighted sequence (DWI) was obtained (3-6 directions, B value 500-800) in the sagittal plane.Studies were consensus reviewed twice by 2 experienced radiologists...
Results
9 patients with 85 spinal lesions were evaluated. 1 patient had colon cancer, 2 patients had hepatocellular carcinoma, 2 patients had non small cell lung cancer, 2 patients had breast cancer, 1 had bladder cancer and 1 had poorly differentiated adenocarcinomaIn terms of conspicuity on diffusion weighted imaging compared to conventional imaging: 23/85 were deemed similar or unchanged, 40/85 were more conspicuous on the diffusion sequence and 16/85 weremore conspicuous on conventional sequences.In addition, 6 lesions that were identified on the DWI sequence were intitially...
Conclusion
DWI is a rapid pulse sequence that may practicallybe added to the routine MR imaging regimen in patients with suspected spinal metastases. It can improve sensitivityof lesion detection and assist inlesion characterization, especially in problematic locations.While previous studies showed mixed results with diffusion based imaging of the spine, new MRI machineswith stronger and faster gradients as well as new coils can improve the signal to noise of acquired images while using intermediate b values of 500-800.Our study has shown that diffusion weighted imaging can improve...
References
1. Dietrich O, Biffar A, Reiser MF, Baur-Melnyk A. Diffusion-weighted imaging of bone marrow. Semin Musculoskelet Radiol. 2009 Jun;13(2):134-442. Karchevsky M, Babb JS, Schweitzer ME. Can diffusion-weighted imaging be used to differentiate benign from pathologic fractures? A meta-analysis. Skeletal Radiol. 2008 Sep;37(9):791-53. Castillo M. Diffusion-weighted imaging of the spine: is it reliable? AJNR Am JNeuroradiol. 2003 Jun-Jul;24(6):1251-334. Balliu E, Vilanova JC, Peláez I, Puig J, Remollo S, Barceló C, Barceló J, Pedraza S. Diagnostic value of apparent diffusion coefficients to differentiate benign from malignant vertebral...