Affiliation:
1. School of Electronic Systems & Automation Digital University Kerala Trivandrum Kerala India
2. High Field Magnetic Resonance Max‐Planck‐Institute for Biological Cybernetics Tübingen Germany
3. Biomedical Magnetic Resonance, Department of Radiology Eberhard Karl's University and University Hospital Tübingen Germany
4. School of Informatics Digital University Kerala Trivandrum Kerala India
Abstract
AbstractPurposeTo develop a method for unwrapping temporally undersampled and nonlinear gradient recalled echo (GRE) phase.Theory and MethodsTemporal unwrapping is performed as a sequential one step prediction of the echo phase, followed by a correction to the nearest integer wrap‐count. A spatio‐temporal extension of the 1D predictor corrector unwrapping (PCU) algorithm improves the prediction accuracy, and thereby maintains spatial continuity. The proposed method is evaluated using numerical phantom, physical phantom, and in vivo brain data at both 3 T and 9.4 T. The unwrapping performance is compared with the state‐of‐the‐art temporal and spatial unwrapping algorithms, and the spatio‐temporal iterative virtual‐echo based Nyquist sampled (iVENyS) algorithm.ResultsSimulation results showed significant reduction in unwrapping errors at higher echoes compared with the state‐of‐the‐art algorithms. Similar to the iVENyS algorithm, the PCU algorithm was able to generate spatially smooth phase images for in vivo data acquired at 3 T and 9.4 T, bypassing the use of additional spatial unwrapping step. A key advantage over iVENyS algorithm is the superior performance of PCU algorithm at higher
echoes.ConclusionPCU algorithm serves as a robust phase unwrapping method for temporally undersampled and nonlinear GRE phase, particularly in the presence of high field gradients.
Funder
Science and Engineering Research Board
Subject
Radiology, Nuclear Medicine and imaging