ENTRY TEARS OF THORACIC AORTIC DISSECTIONS - MR APPEARANCE ON GATED SE IMAGING

Objective: The purpose of this study was to assess the ability of gated SE MR to demonstrate entry tears of thoracic aortic dissections and to elucidate their MR appearance. Materials and Methods: Gated SE MR images of nine consecutive patients with nonthrombosed aortic dissection on aortography were retrospectively analyzed. Results: Magnetic resonance consistently depicted an intimal flap and a double lumen in all nine patients. A focal intimal flap discontinuity suggesting an intimal tear was shown in eight patients. This intimal flap discontinuity was confirmed to be the entry tear by operation in five patients and by aortography in three. In five of eight patients with a focal intimal flap discontinuity, rapid influx of blood across an intimal defect produced a localized signal void area within the false lumen, which was surrounded by slow flow signal showing even-echo rephasing. This MR sign of a localized jet of flow void within the false lumen was very useful in determining the significance of a focal intimal flap discontinuity. Conclusion: Familiarity with these MR appearances of entry tears may enable their preoperative localization in a large proportion of aortic dissections on routine gated SE MRI.