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Rapid estimation of cartilage T2 based on double echo at steady state (DESS) with 3 Tesla
Author(s) -
Welsch Goetz H.,
Scheffler Klaus,
Mamisch Tallal C.,
Hughes Timothy,
Millington Steven,
Deimling Michael,
Trattnig Siegfried
Publication year - 2009
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.22036
Subject(s) - flip angle , imaging phantom , echo (communications protocol) , cartilage , nuclear magnetic resonance , steady state (chemistry) , signal (programming language) , echo time , spin echo , signal to noise ratio (imaging) , magnetic resonance imaging , contrast (vision) , algorithm , mathematics , biomedical engineering , computer science , nuclear medicine , physics , chemistry , medicine , statistics , artificial intelligence , anatomy , radiology , computer network , programming language
The double‐echo‐steady‐state (DESS) sequence generates two signal echoes that are characterized by a different contrast behavior. Based on these two contrasts, the underlying T2 can be calculated. For a flip‐angle of 90°, the calculated T2 becomes independent of T1, but with very low signal‐to‐noise ratio. In the present study, the estimation of cartilage T2, based on DESS with a reduced flip‐angle, was investigated, with the goal of optimizing SNR, and simultaneously minimizing the error in T2. This approach was validated in phantoms and on volunteers. T2 estimations based on DESS at different flip‐angles were compared with standard multiecho, spin‐echo T2. Furthermore, DESS‐T2 estimations were used in a volunteer and in an initial study on patients after cartilage repair of the knee. A flip‐angle of 33° was the best compromise for the combination of DESS‐T2 mapping and morphological imaging. For this flip angle, the Pearson correlation was 0.993 in the phantom study (∼20% relative difference between SE‐T2 and DESS‐T2); and varied between 0.429 and 0.514 in the volunteer study. Measurements in patients showed comparable results for both techniques with regard to zonal assessment. This DESS‐T2 approach represents an opportunity to combine morphological and quantitative cartilage MRI in a rapid one‐step examination. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.