title: Molecular MRI of intracranial thrombus in a rat ischemic stroke model.
abstract: OBJECTIVE
  Intracranial thrombus is a principal feature in most ischemic stroke, and thrombus location and size may correlate with outcome and response to thrombolytic therapy. EP-2104R is a fibrin-specific molecular MR agent that has previously been shown to enhance extracranial and venous sinus thrombi in animal models and, recently, in clinical trials. In this study, we examined whether this fibrin-specific MR probe could noninvasively characterize intracranial arterial thrombi.
  
  
  METHODS
  Embolic stroke was induced in adult rats by occlusion of the right internal carotid artery with an aged thrombus. We used diffusion-weighted imaging, time of flight angiography, and high-resolution 3-dimensional T1-weighted MRI at 4.7 T before and after use of contrast agents EP-2104R (n=6) and gadopentetate dimeglumine (n=5).
  
  
  RESULTS
  In all animals, MR angiography revealed a flow deficit and diffusion-weighted imaging showed hyperintensity consistent with ischemia. Using EP-2104R-enhanced MRI, we saw occlusive thrombi and vessel wall enhancement in all 6 animals with high contrast to noise relative to blood, whereas gadopentetate dimeglumine-injected animals showed no occlusive thrombus or vessel wall enhancement. The concentration of gadolinium in the thrombus after EP-2104R was 18 times that in the blood pool.
  
  
  CONCLUSIONS
  EP-2104R-enhanced MRI successfully identifies intracranial thrombus in a rat embolic stroke model.
authors.affiliation: Department of Radiology, Massachusetts General Hospital-East, 149 13th Street, Suite 2301, Charlestown, MA 02129, USA.
authors.forename: Ritika
authors.initials: R
authors.lastname: Uppal
authors.forename: Ilknur
authors.initials: I
authors.lastname: Ay
authors.forename: Guangping
authors.initials: G
authors.lastname: Dai
authors.forename: Young Ro
authors.initials: YR
authors.lastname: Kim
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
authors.forename: Peter
authors.initials: P
authors.lastname: Caravan
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000494:pharmacology*; D004195:Disease Models, Animal; D005682:Gadolinium / Q000494:pharmacology*; D020767:Intracranial Thrombosis / Q000000981:diagnostic imaging*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D020521:Stroke / Q000000981:diagnostic imaging*; D015912:Thrombolytic Therapy
chemical_list: D003287:Contrast Media; C503783:EP-2104R; D010455:Peptides; D005682:Gadolinium
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