Small vessels in the human brain: MR venography with deoxyhemoglobin as an intrinsic contrast agent.

Abstract
To assess a magnetic resonance (MR) imaging method for depicting small veins in the brain, a three-dimensional, long echo time, gradient-echo sequence that depended on the paramagnetic property of deoxyhemoglobin was used. Veins with diameters smaller than a pixel were depicted. This MR imaging method is easy to implement and may prove helpful in the evaluation of venous diseases.