Abdominal ImagingT1 Pseudohyperintensity on Fat-Suppressed Magnetic Resonance Imaging: A Potential Diagnostic PitfallHuynh, Tuan N. BA; Johnson, Thor MD, PhD; Poder, Liina MD; Joe, Bonnie N. MD, PhD; Webb, Emily M. MD; Coakley, Fergus V. MD, MB, BChAuthor Information From the Department of Radiology and Biomedical Imaging, University of California San Francisco, CA. Received for publication April 8, 2011; accepted April 29, 2011. Reprints: Fergus V. Coakley, MD, MB, BCh, Box 0628, M-372, 505 Parnassus Ave, San Francisco, CA 94143-0628 (e-mail: Fergus.Coakley@radiology.ucsf.edu). T.J. was supported by the National Institute of Biomedical Imaging and Bioengineering T32 training grant T32 EB001631. Journal of Computer Assisted Tomography: July-August 2011 - Volume 35 - Issue 4 - p 459-461 doi: 10.1097/RCT.0b013e31822227c3 Buy Metrics Abstract Magnetic resonance imaging findings in 2 patients with misleading T1 hyperintensity seen only on fat-suppressed images are presented; one with a renal cell carcinoma that was misinterpreted as a hemorrhagic cyst and the other with an ovarian serous cystadenocarcinoma that was misinterpreted as a complicated endometrioma. The apparent T1 hyperintensity on fat-suppressed images in these cases was likely due to varying perception of image signal dependent on local contrast, an optical effect known as the checker-shadow illusion. T1 pseudohyperintensity should be considered when apparently high T1 signal intensity is seen only on fat-suppressed images; review of non-fat-suppressed images may help prevent an erroneous diagnoses of blood-containing lesions. © 2011 Lippincott Williams & Wilkins, Inc.