Diffusion-weighted MR imaging of upper abdominal organs: field strength and intervendor variability of apparent diffusion coefficients.
OBJECTIVE
To determine the variability of apparent diffusion coefficient (ADC) values in various anatomic regions in the upper abdomen measured with magnetic resonance (MR) systems from different vendors and with different field strengths.


METHODS
Ten healthy men (mean age, 36.6 years ± 7.7 [standard deviation]) gave written informed consent to participate in this prospective ethics committee-approved study. Diffusion-weighted (DW) MR imaging was performed in each subject with 1.5- and 3.0-T MR systems from each of three vendors at two institutions. Two readers independently measured ADC values in seven upper abdominal regions (left and right liver lobe, gallbladder, pancreas, spleen, and renal cortex and medulla). ADC values were tested for interobserver differences, as well as for differences related to field strength and vendor, with repeated-measures analysis of variance; coefficients of variation (CVs) and variance components were calculated.


RESULTS
Interreader agreement was excellent (intraclass coefficient, 0.876). ADC values were (77.5-88.8) ×10(-5) mm(2)/sec in the spleen and (250.6-278.5) ×10(-5) mm(2)/sec in the gallbladder. There were no significant differences between ADC values measured at 1.5 T and those measured at 3.0 T in any anatomic region (P >.10 for all). In two of seven regions at 1.5 T (left and right liver lobes, P < .023) and in four of seven regions at 3.0 T (left liver lobe, pancreas, and renal cortex and medulla, P < .008), intervendor differences were significant. CVs ranged from 7.0% to 27.1% depending on the anatomic location.


CONCLUSIONS
Despite significant intervendor differences in ADC values of various anatomic regions of the upper abdomen, ADC values of the gallbladder, pancreas, spleen, and kidney may be comparable between MR systems from different vendors and between different field strengths.
From the Institute of Diagnostic and Interventional Radiology (O.F.D., D.N., A.B.) and University School of Medicine (E.A.), University Hospital Zurich, Zurich, Switzerland; Department of Radiology, Neuroradiology and Nuclear Medicine, Institute of Diagnostic, Interventional and Pediatric Radiology, University of Bern, Inselspital, Freiburgstrasse 10, CH-3010 Bern, Switzerland (D.C., J.M.F., H.C.T.); and Division of Biostatistics, Institute of Social and Preventive Medicine, University of Zurich, Zurich, Switzerland (B.S.).
Olivio F
OF
Donati
Daniel
D
Chong
Daniel
D
Nanz
Andreas
A
Boss
Johannes M
JM
Froehlich
Erik
E
Andres
Burkhardt
B
Seifert
Harriet C
HC
Thoeny
D000005:Abdomen / Q000033:anatomy & histology*; D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005704:Gallbladder / Q000033:anatomy & histology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000033:anatomy & histology; D008099:Liver / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000033:anatomy & histology; D011446:Prospective Studies; D012016:Reference Values; D013154:Spleen / Q000033:anatomy & histology