Comparison of apparent diffusion coefficients and distributed diffusion coefficients in high-grade gliomas.
OBJECTIVE
To compare apparent diffusion coefficients (ADCs) with distributed diffusion coefficients (DDCs) in high-grade gliomas.


METHODS
Twenty patients with high-grade gliomas prospectively underwent diffusion-weighted MRI. Traditional ADC maps were created using b-values of 0 and 1000 s/mm(2). In addition, DDC maps were created by applying the stretched-exponential model using b-values of 0, 1000, 2000, and 4000 s/mm(2). Whole-tumor ADCs and DDCs (in 10(-3) mm(2)/s) were measured and analyzed with a paired t-test, Pearson's correlation coefficient, and the Bland-Altman method.


RESULTS
Tumor ADCs (1.14 +/- 0.26) were significantly lower (P = 0.0001) than DDCs (1.64 +/- 0.71). Tumor ADCs and DDCs were strongly correlated (R = 0.9716; P < 0.0001), but mean bias +/- limits of agreement between tumor ADCs and DDCs was -0.50 +/- 0.90. There was a clear trend toward greater discordance between ADC and DDC at high ADC values.


CONCLUSIONS
Under the assumption that the stretched-exponential model provides a more accurate estimate of the average diffusion rate than the mono-exponential model, our results suggest that for a little diffusion attenuation the mono-exponential fit works rather well for quantifying diffusion in high-grade gliomas, whereas it works less well for a greater degree of diffusion attenuation.
Kwee
Thomas C
TC
Department of Radiology, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA.
Galbán
Craig J
CJ
Tsien
Christina
C
Junck
Larry
L
Sundgren
Pia C
PC
Ivancevic
Marko K
MK
Johnson
Timothy D
TD
Meyer
Charles R
CR
Rehemtulla
Alnawaz
A
Ross
Brian D
BD
Chenevert
Thomas L
TL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001932:Brain Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D003198:Computer Simulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005910:Glioma / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity