Chemical shift imaging: An indispensable tool in diagnosing musculoskeletal pathologies

Chemical shift imaging (CSI) is an important fat-suppression technique in magnetic resonance imaging (MRI); it is used routinely in abdominal imaging to detect the presence of intralesional fat. Its utility in musculoskeletal imaging has recently gained interest as a technique that is complementary to routine imaging. It is believed to aid in diagnosing and differentiating various osseous pathologies. This review describes the role of CSI as an imaging technique for diagnosing various osseous and periarticular pathologies in different clinical scenarios.

Role of Diffusion-Weighted and Chemical Shift Magnetic Resonance Imaging in Differentiation of Benign and Malignant Spinal Fractures

Atraumatic spinal compression fractures are common clinical problem. Differentiating benign osteoporotic fractures from pathological fractures due to malignant/metastatic lesions affects the management and prognoses in patients with known extraspinal malignancy. The objective of the research was to assess the role of conventional magnetic resonance imaging sequences with diffusion-weighted imaging and chemical-shift imaging in differentiating benign and malignant acute spinal compression fractures. Materials and Methods. The study included 40 patients with acute spinal compression fractures. Patients were evaluated using magnetic resonance imaging with diffusion-weighted imaging and chemical-shift imaging to differentiate benign etiology from malignant one. The results obtained were compared with histopathological follow-up for 6 months for definite clinical diagnoses. Results. No significant difference was noted in signal characteristics of benign and malignant fractures on T1, T2 and short-tau inversion recovery. However, posterior element involvement, soft tissue component and post-contrast enhancement were seen more frequently in malignant fractures (p<0.05). On diffusion-weighted images, 77.8% of malignant fractures were hyperintense and 59.1% of benign fractures were hypointense (p<0.05). The mean apparent diffusion coefficient value was 0.81 ± 0.19 for malignant and 1.24 ± 0.24 for benign fractures (p<0.5). The mean signal intensity ratio for malignant fractures was 0.91 ± 0.125, whereas the signal intensity ratio for benign fractures was 0.64 ± 0.096 (p<0.001). Conclusions. Signal characteristics on T1, T2 and short-tau inversion recovery sequences do not differentiate benign from malignant fractures; however, posterior element involvement, soft tissue and post contrast enhancement help in differentiating the etiology. Diffusion-weighted imaging and apparent diffusion coefficient values, as well as using chemical shift imaging further improve the diagnostic accuracy of magnetic resonance imaging.