title: Experimental intracerebral and subarachnoid/intraventricular haemorrhages.
abstract: OBJECTIVE
  To compare the detectability of small experimental intracranial haemorrhages on MR imaging at 0.5 T and 1.5 T, from hyperacute to subacute stages.
  
  
  METHODS
  1 ml of autologous blood was injected into the brain of 15 rabbits to create intraparenchymal haematomas. Since the blood partially escaped into the cerebrospinal fluid (CSF) spaces, detectability of subarachnoid and intraventricular blood was also evaluated. MR imaging at 0.5 T and at 1.5 T was repeated up to 14 days, including T1-, proton density- and T2-weighted (w) spin-echo (SE), FLAIR and T2*-w gradient echo (GE) pulse sequences. The last MR investigation was compared to the formalin-fixed brain sections in 7 animals.
  
  
  RESULTS
  The intraparenchymal haematomas were best revealed with T2*-w GE sequences, with 100% of sensitivity at 1.5 T and 90-95% at 0.5 T. Blood in the CSF spaces was significantly (p < 0.05) better detected at 1.5 T with T2*-w GE sequences and detected best during the first 2 days. The next most sensitive sequence for intracranial blood was FLAIR. SE sequences were rather insensitive.
  
  
  CONCLUSIONS
  1.5 T equipment is superior to 0.5 T in the detection of intracranial haemorrhages from acute to subacute stages. T2*-w GE sequences account for this result but other sequences are also needed for a complete examination.
authors.affiliation: Department of Radiology, Uppsala University Hospital, Sweden.
authors.forename: M Alemany
authors.initials: MA
authors.lastname: Ripoll
authors.forename: R
authors.initials: R
authors.lastname: Raininko
mesh_terms: D000818:Animals; D002543:Cerebral Hemorrhage / Q000473:pathology*; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods; D011817:Rabbits; D013345:Subarachnoid Hemorrhage / Q000473:pathology*