RT Journal Article
SR Electronic
T1 A Simplified Model for Intravoxel Incoherent Motion Perfusion Imaging of the Brain
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 2251
OP 2257
DO 10.3174/ajnr.A4929
VO 37
IS 12
A1 J. Conklin
A1 C. Heyn
A1 M. Roux
A1 M. Cerny
A1 M. Wintermark
A1 C. Federau
YR 2016
UL http://www.ajnr.org/content/37/12/2251.abstract
AB BACKGROUND AND PURPOSE: Despite a recent resurgence, intravoxel incoherent motion MRI faces practical challenges, including limited SNR and demanding acquisition and postprocessing requirements. A simplified approach using linear fitting of a subset of higher b-values has seen success in other organ systems. We sought to validate this method for evaluation of brain pathology by comparing perfusion measurements using simplified linear fitting to conventional biexponential fitting.MATERIALS AND METHODS: Forty-nine patients with gliomas and 17 with acute strokes underwent 3T MRI, including DWI with 16 b-values (range, 0–900 s/mm2). Conventional intravoxel incoherent motion was performed using nonlinear fitting of the standard biexponential equation. Simplified intravoxel incoherent motion was performed using linear fitting of the log-normalized signal curves for subsets of b-values >200 s/mm2. Comparisons between ROIs (tumors, strokes, contralateral brain) and between models (biexponential and simplified linear) were performed by using 2-way ANOVA. The root mean square error and coefficient of determination (R2) were computed for the simplified model, with biexponential fitting as the reference standard.RESULTS: Perfusion maps using simplified linear fitting were qualitatively similar to conventional biexponential fitting. The perfusion fraction was elevated in high-grade (n = 33) compared to low-grade (n = 16) gliomas and was reduced in strokes compared to the contralateral brain (P < .001 for both main effects). Decreasing the number of b-values used for linear fitting resulted in reduced accuracy (higher root mean square error and lower R2) compared with full biexponential fitting.CONCLUSIONS: Intravoxel incoherent motion perfusion imaging of common brain pathology can be performed by using simplified linear fitting, with preservation of clinically relevant perfusion information.Ddiffusion coefficientD*pseudo-diffusion coefficientfperfusion fractionIVIMintravoxel incoherent motionrCBVrelative cerebral blood volume