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Simultaneous T 2 and lipid quantitation using IDEAL‐CPMG
Author(s) -
Janiczek Robert L.,
Gambarota Giulio,
Sinclair Christopher D. J.,
Yousry Tarek A.,
Thornton John S.,
Golay Xavier,
Newbould Rexford D.
Publication year - 2011
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.22916
Subject(s) - ideal (ethics) , nuclear magnetic resonance , chemistry , physics , philosophy , epistemology
Muscle damage, edema, and fat infiltration are hallmarks of a range of neuromuscular diseases. The T 2 of water, T 2,w , in muscle lengthens with both myocellular damage and inflammation and is typically measured using multiple spin‐echo or Carr–Purcell–Meiboom–Gill acquisitions. However, microscopic fat infiltration in neuromuscular diseases prevents accurate T 2,w quantitation as the longer T 2 of fat, T 2,f , masks underlying changes in the water component. Fat saturation can be inconsistent across the imaging volume and removes valuable physiological fat information. A new method is presented that combines iterative decomposition of water and fat with echo asymmetry and least squares estimation with a Carr–Purcell–Meiboom–Gill–sequence. The sequence results in water and fat separated images at each echo time for use in T 2,w and T 2,f quantification. With knowledge of the T 2,w and T 2,f , a T 2 ‐corrected fat fraction map can also be calculated. Monte‐Carlo simulations and measurements in phantoms, volunteers, and a patient with inclusion body myositis are demonstrated. In healthy volunteers, uniform T 2,w and T 2 ‐corrected fat fraction maps are present within all muscle groups. However, muscle‐specific patterns of fat infiltration and edema are evident in inclusion body myositis, which demonstrates the power of separating and quantifying the fat and water components. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.