Subtraction images: A really helpful tool in non-vascular MRI

Abstract

Subtraction imaging is a technique whereby an unenhanced T1-weighted sequence is digitally subtracted from the identical sequence performed after gadolinium administration. This study will highlight the role of subtraction imaging for non-vascular MRI applications. The study included 40 patients presenting with lesions in different parts of the body, that are initially hyperintense on T1W sequences. We used post-processing software (Osirix) to digitally subtract the pre-enhancement from the post enhancement sequences. Based on subtraction imaging findings 5 patients were diagnosed with intraocular melanomas, two patients were diagnosed with hemorrhagic cysts in the masseter muscle, two patients were diagnosed with hemorrhagic cysts in the parotid gland, two patients were diagnosed with dysplastic hepatic nodules, 5 patients were diagnosed with post-ablation necrosis following hepatocellular carcinoma (HCC) treatment, two patients showed recurrent HCC after chemoembolisation, 3 patients showed chemoembolised HCC without recurrence, 4 patients showed intraluminal gall bladder sludge, 4 patients showed hemorrhagic renal cysts, one patient showed solid papillary neoplasm of the pancreas, 6 patients showed chocolate ovarian cysts, two patient showed ovarian cystadenoma and two patients showed ovarian cystadenocarcinoma. Subtraction MRI is very helpful tool in non-vascular MRI applications.