Image subtraction in gadolinium-enhanced MR imaging.

Image subtraction in gadolinium-enhanced MR imaging is a broadly applicable postprocessing technique that can be used with any field strength and T1-weighted sequence. This technique is typically a quick and efficient means of obtaining fat suppression that avoids the limitations of incomplete fat saturation due to field inhomogeneity and increased imaging times associated with conventional fat-suppression techniques. In particular, image subtraction may be valuable on lower strength magnetic field systems that lack effective chemical-shift fat-suppression techniques. Because source data are viewed in conjunction with subtracted images, image subtraction is unlikely to introduce errors in interpretation. By performing unenhanced and enhanced sequences in a manner amenable to image subtraction, radiologists should find this technique to be a useful and almost cost-free option.