Comparison of Phase-contrast MRA with TCD, with Special Reference to the Ophthalmic Artery and Superior Ophthalmic Vein.

Transcranial Doppler sonography (TCD) is a useful method for investigating the hemodynamics of cerebral arteries. Phase-contrast (PC) MRA measures a vector quantity that contains information about blood flow direction and velocity. The purpose of this study was to evaluate the clinical usefulness of these modalities for investigating the hemodynamics of the ophthalmic artery (OA) and superior ophthalmic vein (Soy) . Between 1991 and 1996, ten patients with moyamoya disease and 6 patients with carotid-cavernous fistula (CCF) were evaluated using both methods. TCD was carried out through the orbital window. On the other hand, three-dimensional PC MRA and two-dimensional PC cine MRI were used with various velocity encoding gradient, and the flow direction in the OA and SOV was evaluated from the phase image. The results were as follows: (1) In moyamoya disease, the mean flow velocity (MFV) in the ophthalmic artery was relatively high, and reverse flow was seen in 3 of the 20 affected sides in both the TCD and PC MRA. (2) In CCF, the MFV in the SOV by TCD was elevated, although the level of the optimal velocity by PC MRA was relatively low. In conclusion, both TCD and PC MRA are clinically useful for evaluating the hemodynamics of the OA and SOV in moyamoya disease and CCF. Comprehensive evaluation using these two modalities should be done to understand the hemodynamics of these diseases.