The effect of hypertonic saline solution on vasodilatation of the superior sagittal sinus using magnetic resonance imaging in normovolemic dogs

Several animal studies have demonstrated the beneficial effects of hypertonic saline (HSS) on cerebral blood flow, intracranial pressure and brain water content. This study aimed to investigate, using magnetic resonance imaging, whether a small volume of HSS is superior to dextran in vasodilatation of cerebral vessels and reduction of cerebrospinal fluids in dogs. HSS induced a significant expansion of the cross-section of the superior sagittal sinus in the axial transverse section of the pituitary and a decrease in cerebrospinal fluid area in the axial transverse section of the epencephalon more than dextran 40 did (p < 0.001, respectively). However, the relative plasma volume in the dog which received dextran 40 was significantly higher after t = 30 min than in the HSS group (p < 0.001). Therefore, it is suggested that HSS might be superior to colloid solutions in improving cerebral circulation, whereas dextran 40 is superior to HSS in enhancing systemic circulation in dogs.