Vascular permeability precedes spontaneous intracerebral hemorrhage in stroke-prone spontaneously hypertensive rats

BACKGROUND AND PURPOSE - Stroke-prone spontaneous hypertensive rats (SHRsp) fed a high-salt diet develop malignant hypertension, blood-brain barrier breakdown, and spontaneous intracerebral hemorrhage (ICH). The precise spatial and temporal relationship between these events has not been well-delineated. METHODS - Ten SHRsp male rats, fed a high-salt diet, were imaged weekly using MRI, starting at 12 weeks of age. T1-weighted (with and without Gd), T2-weighted, and T2* sequences were acquired. Permeability maps were calculated. RESULTS - Seven SHRsp rats had spontaneous ICH develop before death. Five of the 7 rats had focally increased vascular permeability at the site of the ICH; 3 of these rats had vascular permeability 1 to 2 weeks before spontaneous ICH. CONCLUSIONS - Salt-loaded SHRsp rats have increased vascular permeability up to 2 weeks before ICH, predicting hemorrhage both in space and time. These results suggest that hypertensive ICH is preceded by focal vasculopathy detectable by Gd leak.