High Dynamic Range Processing for Magnetic Resonance Imaging

Purpose: To minimize feature loss in T-1- and T-2-weighted MRI by merging multiple MR images acquired at different T-R and T-E to generate an image with increased dynamic range. Materials and Methods: High Dynamic Range (HDR) processing techniques from the field of photography were applied to a series of acquired MR images. Specifically, a method to parameterize the algorithm for MRI data was developed and tested. T-1- and T-2-weighted images of a number of contrast agent phantoms and a live mouse were acquired with varying T-R and TE parameters. The images were computationally merged to produce HDR-MR images. All acquisitions were performed on a 7.05 T Bruker PharmaScan with a multi-echo spin echo pulse sequence. Results: HDR- MRI delineated bright and dark features that were either saturated or indistinguishable from background in standard T-1- and T-2-weighted MRI. The increased dynamic range preserved intensity gradation over a larger range of T-1 and T-2 in phantoms and revealed more anatomical features in vivo. Conclusions: We have developed and tested a method to apply HDR processing to MR images. The increased dynamic range of HDR- MR images as compared to standard T-1- and T-2-weighted images minimizes feature loss caused by magnetization recovery or low SNR.