Magnetic Resonance Imaging (MRI) With Artifact-Free T2 Mapping

摘要

Example apparatus and methods provide improved quantitative T2 mapping for magnetic resonance imaging (MRI). Conventional T2 (spin-spin) mapping in MRI may employ a spin echo with multiple echoes (SEMC) approach like the Carr-Purcell-Meiboom-Gill (CPMG) spin echo sequence. These conventional approaches may be negatively impacted by a slice profile effect that incorrectly and undesirably lowers the signal of a first echo and by a stimulated echo effect that incorrectly and undesirably raises the signal for even echoes. Example apparatus mitigate these issues by using a T2 preparation phase that uses three dimensional (3D) non-slice selective block RF pulses followed by a multi-echo data acquisition that uses an in-out k-space trajectory. The multi-echo acquisition may employ k-space segmentation to acquire one line of partition encodings per T2 preparation phase. While conventional systems mix T2 preparation and multi-echo acquisition, example apparatus and methods separate T2 preparation and multi-echo acquisition.

主权项

1. A non-transitory computer-readable storage medium storing instructions that when performed by a computer control the computer to perform a method to control a magnetic resonance imaging (MRI) apparatus, the method comprising:
controlling the MRI apparatus to apply gradients and radio frequency (RF) energy to a sample according to a pulse sequence, where the gradients and RF energy produce nuclear magnetic resonance (NMR) in the sample; controlling the MRI apparatus to acquire NMR signals produced by the sample in response to the applied gradients and RF energy; and producing an artifact free T2 parameter map from the acquired NMR signals, where the pulse sequence includes a T2 preparation phase followed by a data acquisition phase, where the T2 preparation phase and the data acquisition phase do not overlap in time, where the T2 preparation phase includes three or more three dimensional (3D) block non-slice selective RF pulses, where the acquired NMR signals include two or more spin echoes per T2 preparation phase, and where the two or more spin echoes are produced in response to the same applied gradients and RF energy.