title: Subacute clot mimicking flow in a thrombosed arterial bypass graft on two-dimensional time-of-flight and three-dimensional contrast-enhanced MRA.
abstract: Subacute intravascular thrombus can contain methemoglobin, which results in very short spin-lattice (T1) relaxation times. We describe a case of a 78-year-old man with increasing right lower extremity claudication. The patient had a thrombosed arterial bypass graft showing high signal intensity that mimicked flow on both two-dimensional time-of-flight and three-dimensional contrast-enhanced MR angiography. Misinterpretation of the high signal thrombus as flowing blood can be avoided by obtaining a precontrast T1-weighted sequence.
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104-4283, USA.
authors.forename: E K
authors.initials: EK
authors.lastname: Insko
authors.forename: E S
authors.initials: ES
authors.lastname: Siegelman
authors.forename: A H
authors.initials: AH
authors.lastname: Stolpen
mesh_terms: D000368:Aged; D006083:Graft Occlusion, Vascular / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007866:Leg / Q000098:blood supply; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012039:Regional Blood Flow; D013927:Thrombosis / Q000175:diagnosis*