Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) of the wrist and finger at 3T: comparison with chemical shift selective fat suppression images.
OBJECTIVE
To compare fat-suppressed magnetic resonance imaging (MRI) quality using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) with that using chemical shift selective fat-suppressed T1-weighted spin-echo (CHESS) images for evaluating rheumatoid arthritis (RA) lesions of the hand and finger at 3T.


METHODS
MRI was performed in eight healthy volunteers and eight RA patients with a 3.0T MR system (Signa HDxt GE healthcare) using an eight-channel knee coil. FS-CHESS-T1-SE and IDEAL imaging were acquired in the coronal planes covering the entire structure of the bilateral hands with a slice thickness of 2 mm. In the RA patients both images were obtained after intravenous gadolinium administration. Image quality was evaluated on a five-point scale (1 = excellent to 5 = very poor). Synovitis and bone marrow contrast uptake on MR images were reviewed by two musculoskeletal radiologists using the Rheumatoid Arthritis MRI Scoring System (RAMRIS) of the Outcome Measures in Rheumatoid Arthritis Clinical Trials (OMERACT) group.


RESULTS
IDEAL showed uniform FS unaffected by magnetic field inhomogeneity and challenging geometry of hand and fingers, while CHESS-T1-SE often showed FS failure within the first metacarpal joint, tip of the finger, and ulnar aspect of the wrist joint. Overall image quality was significantly better with IDEAL than CHESS-T1-SE images (4.43 vs. 3.43, P < 0.01). Interobserver agreement (κ value) for synovitis and bone marrow contrast uptake was good to excellent with IDEAL (0.74-0.91, 0.62-0.89, respectively).


CONCLUSIONS
IDEAL could compensate for the effects of field inhomogeneities, providing uniform FS of the hand and finger than did the CHESS-T1-SE sequence.
Department of Radiology, University of Occupational and Environmental Health, Kitakyushu, Japan. a-taka@med.uoeh-u.ac.jp
Takatoshi
T
Aoki
Yoshiko
Y
Yamashita
Hodaka
H
Oki
Hiroyuki
H
Takahashi
Yoshiko
Y
Hayashida
Kazuyoshi
K
Saito
Yoshiya
Y
Tanaka
Yukunori
Y
Korogi
D000273:Adipose Tissue; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000473:pathology*; D001853:Bone Marrow / Q000473:pathology; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D005385:Fingers / Q000473:pathology*; D005682:Gadolinium / Q000008:administration & dosage; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016018:Least-Squares Analysis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D013585:Synovitis / Q000473:pathology; D014867:Water; D014955:Wrist Joint / Q000473:pathology*
D003287:Contrast Media; D014867:Water; D005682:Gadolinium