Dual-energy CT: a promising new technique for assessment of the musculoskeletal system.

OBJECTIVE: Dual-energy CT (DECT) characterizes the chemical composition of material according to its differential x-ray attenuation at two different energy levels. Applications of DECT in musculoskeletal imaging include imaging of bone marrow edema, tendons, and ligaments and the use of monoenergetic techniques to minimize metal prosthesis beam-attenuating artifacts. CONCLUSION: The most validated application of DECT is undoubtedly its noninvasive and highly specific ability for confirming the presence of monosodium urate deposits in the assessment of gout.

Detecting lesions in multiple sclerosis at 4.7 tesla using phase susceptibility-weighting and T2-weighting.

PURPOSE: To demonstrate 4.7 Tesla (T) imaging methods for visualizing lesions in multiple sclerosis in the human brain using phase susceptibility-weighting and T2 weighting. MATERIALS AND METHODS: Seven patients with relapsing-remitting multiple sclerosis were imaged at 4.7T using three-dimensional (3D) susceptibility-weighted imaging (SWI) with 0.90 mm(3) voxel volumes, and with 2D T2-weighted fast spin echo (T2WFSE) with 0.34 mm(3) voxels and 1.84 mm(3) voxels. The visibility of MS lesions at 4.7T with phase SWI and T2WFSE was assessed by independent lesion counts made by an experienced neuroradiologist, and by quantitative measures. RESULTS: High resolution T2WFSE at 4.7T provided excellent depiction of hyperintense lesions. When combined with phase SWI, 124 total lesions were identified of which 18% were only visible on phase SWI and not on T2WFSE. The phase lesions had a mean phase shift relative to local background of -11.15 +/- 5.97 parts per billion. CONCLUSION: Imaging at 4.7T can provide both high quality, high resolution T2WFSE and SWI for visualization of lesions in multiple sclerosis. Phase susceptibility-weighting can identify additional lesions that are not visible with high resolution T2WFSE.