Preservation of sickle cell blood-flow patterns during MR imaging: an in vivo study.

Magnetic fields and RF energy have been shown to affect sickle erythrocytes in vitro. Because both strong magnetic fields and RF energy are used in MR imaging, it has been suggested that capillary blood flow in patients with sickle cell disease may be altered during MR imaging. In order to examine sickle cell blood flow during MR imaging in vivo, laser-Doppler velocimetry was performed in normal control subjects and in sickle cell subjects before, during, and after MR imaging at 0.35 and 1.5 T. Mean blood flow and patterns of blood-flow variability were compared by two hematologists. No differences were found on the recordings from each subject made before, during, and after MR imaging were compared. Blood-flow patterns generally differed between control and sickle cell subjects. Periodic oscillatory blood flow, reportedly a specific finding in sickle cell subjects, was observed in one control subject and was not consistently found in sickle cell subjects. Although energies employed during MR imaging have effects on sickle erythrocytes in vitro, our data show no changes in sickle cell blood flow during MR imaging in vivo.