Volume rendered 3D reconstruction of MRA images vs MRA MIP reconstruction in the evaluation of aortic dissection

Purpose: To evaluate the potential advantages of the volume rendering (VR) 3D algorithm vs maximum intensity projection (MIP) reconstruction in the MR evaluation of aortic dissection. Materials and Methods: Thirty-four patients affected by aortic dissection underwent MRA evaluation employing a 1.5 T superconductive magnet (GE Signa Horizon 8.3) with phased-array coil. The examination was performed using a 3D SPGR sequence acquired during automatic injection of 0.2 mmol/kg of Gd-BOPTA. Images were double-blindly reviewed by two radiologists after MIP and VR reconstruction algorithm. Evidence of intimal flap, aortic branch involvement and extension of the aortic dissection were analyzed. Interobserver agreement was obtained after source image evaluation. Results: Both algorithms required at least 3 min of post-processing. VR reconstruction provided better 3D effects compared with MIP reconstruction, with more precise detection of the intimal flap (VR x/34 p= x; MIP x/34 p=x) and its aortic extension (VR x/34 p= x; MIP x/34 p=x). Aortic branch involvement was better seen on VR reconstructions (VR x/34 p= x; MIP x/34 p=x). Conclusion: VR reconstruction is an efficient technique for generation of 3D images from MR data set. It provides a better comprehension of the intimal flap, especially when there is an involvement of tortuous vessels, in comparison with MIP reconstruction.