Vasodilating in MR-Angiography: a comparison of techniques

Purpose: To verify the hypothesis that a drug that causes vasodilation can contribute to improvement in MRA spatial resolution. To test this hypothesis, a comparison was made between the images obtained using the high resolution time-of-flight (TOF HR 3D) technique and the TOF 3D MTC TONE technique. Methods: From November 1993 to December 1994, we studied 40 patients, of which 20 patients (16 males and 4 females; agerage age of 10 years; range from 3 to 20 years) we examined after they had inhaled Isoflurane (experimental group), and 20 patients (16 males and 4 females ; average age 9.7 years; range from 3 to 12 years) were examined with standard MRA (control group). Results: The vasodilator in both HR MRA and MTC TONE MRA permits a better spatial visualization with respect to the clinical routine MRA. On the other hand, it is true that MTC TONE gives better visualization of the small vessels. Discussion: In our experience, this preliminary study indicates that with respect to routine MR, the spatial resolution is notably increased when isoflurane is used. The signal-to-noise ratio is increased but, moreover, the ability to visualize small vessels is increased. Conclusion: The preliminary results obtained in this study indicate that a pharmacological drugs is capable of increasing the vascular detail of MRA images of the intracranial vessels and that continued research this direction is called for.