Three-dimensional, isotropic MRI: a unified approach to quantification and visualization in congenital heart disease

Abstract

Current standards in magnetic resonance imaging of congenital heart disease are based mostly on anisotropic protocols to image both morphology and function. Operator-dependent acquisition planning is typically needed to obtain the desired images. We propose to instead use operator-independent, three-dimensional, isotropic imaging protocols to acquire both morphology and function (cine and flow) of the entire heart in a few standardized acquisitions. Subsequently, due to the isotropic property of the data, any desired imaging plane can be "imaged" offline by interactive planar reformatting and used for qualitative and quantitative diagnostic evaluation. Morphological data was acquired in patients using 3D steady state free precession (SSFP) protocols, and functional data in volunteers using multislice 2D or 3D cine SSFP as well as 3D, three-component phase-contrast velocity mapping with EPI readouts. Tools to integrate morphological and functional offline image evaluation based on interactive planar reformatting, volume rendering, and corresponding quantification tools were implemented and discussed. We successfully acquired and integrated morphology and flow and demonstrated potential clinical applications. User independent acquisitions of morphological and functional isotropic 3D datasets with real-time, interactive planar reformatting, volume rendering, and integration of morphology and function, have the potential to replace conventional, user dependent, anisotropic 2D imaging in patients with cardiac malformations.