Rationale and Objectives. Knowledge of the in vivo relaxivity of paramagnetic contrast agents is important in the accurate measurement of the permeability of the blood-brain barrier (BBB). This study was aimed at developing an animal model for the magnetic resonance (MR) imaging investigation of injuries to the BBB. Methods. MR imaging (1.9 T) was performed in 18 rats with acute, stable injuries to the brain caused by freezing. After injection of gadodiamide (0.05-0.20 mmol/kg), estimates were made of BBB permeability, leakage space, and relaxivity (also measured in saline). Results. The BBB was always disrupted at the injured site (permeability = 0.038 min-1 ± 0.0006). The central area of necrosis and the periphery of edema showed substantial differences in leakage space and relaxivity. The relaxivity of gadodiamide was much greater at the injured site than in saline. Conclusion. The in vivo relaxivity at a site of pathologic change in the brain may be substantially greater than that measured in aquo.
- Blood-brain barrier
- Brain, MR
- Brain, injuries
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging