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Rapid 3D‐T 1ρ mapping of the knee joint at 3.0T with parallel imaging
Author(s) -
Pakin S. Kubilay,
Xu Jian,
Schweitzer Mark E.,
Regatte Ravinder R.
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20982
Subject(s) - reproducibility , imaging phantom , flip angle , biomedical engineering , scanner , nuclear medicine , nuclear magnetic resonance , repeatability , materials science , magnetic resonance imaging , physics , medicine , radiology , mathematics , optics , statistics
Three‐dimensional spin‐lattice relaxation time in the rotating frame (3D‐T 1ρ ) with parallel imaging at 3.0T was implemented on a whole‐body clinical scanner. A 3D gradient‐echo sequence with a self‐compensating spin‐lock pulse cluster was combined with generalized autocalibrating partially parallel acquisitions (GRAPPA) to acquire T 1ρ ‐weighted images. 3D‐T 1ρ maps of an agarose phantom and three healthy subjects were constructed using an eight‐channel phased‐array coil without parallel imaging and with parallel imaging acceleration factors of 2 and 3, in order to assess the reproducibility of the method. The coefficient of variation (CV) of the median T 1ρ of the agarose phantom was 0.44%, which shows excellent reproducibility. The reproducibility of in vivo 3D‐T 1ρ maps was also investigated in three healthy subjects. The CV of the median T 1ρ of the patellar cartilage varied between ∼1.1% and 4.3%. Similarly, the CV varied between ∼2.1–5.8%, ∼1.4–8.7%, and ∼1.5–4.1% for the biceps femoris and lateral and medial gastrocnemius muscles, respectively. The preliminary results demonstrate that 3D‐T 1ρ maps can be constructed with good reproducibility using parallel imaging. 3D‐T 1ρ with parallel imaging capability is an important clinical tool for reducing both the total acquisition time and RF energy deposition at 3T. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.