Multiresolution MRI temperature monitoring in a reduced field of view |
| |
Authors: | Aljallad Mohammed H Yuan Jing Pilatou Magdalini C McDannold Nathan J Panych Lawrence P |
| |
Institution: | aDepartment of Physics, University of Massachusetts Lowell, Lowell, MA, USA;bDepartment of Radiology, Wilford Hall Medical Center, US Air Force;cDepartment of Imaging and1 Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong;dDepartment of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, USA |
| |
Abstract: | PurposeThe purpose was to develop a new magnetic resonance imaging technique for fast temperature monitoring with extended volume coverage.Materials and MethodsThe Multiple Resolutions Along Phase-Encode and Slice-Select Dimensions (MURPS) method was implemented in both a two-dimensional (2D) spoiled gradient echo (SPGR) sequence and a multishot echo-planar imaging (EPI) sequence. Both modified sequences were used to acquire image data from three slices with variable phase-encode resolution and slice thickness. In the SPGR sequence, a 2D resonant frequency pulse was also implemented to enable imaging within a reduced field of view, and this was used to monitor (at 1.5 T) the temperature changes in a live rabbit and in gel phantoms heated by focused ultrasound. A modified EPI sequence was tested during heating of a phantom undergoing motion.ResultsThe in vivo experiments demonstrated that temperature changes in unexpected locations away from the focal plane, such as near bone structures, could be detected due to the extra volume coverage afforded by the MURPS method. Temperature changes in a moving phantom were resolved using the MURPS EPI sequence with an acquisition rate of three slices every 300 ms.ConclusionThe MURPS method enables temperature monitoring over multiple slices without loss of temporal resolution compared with single-slice imaging and, if combined with multishot EPI, enables volume temperature monitoring in moving organs. |
| |
Keywords: | MRI Temperature mapping Reduced field of view MURPS Focused ultrasound 2DRF excitation |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|