RSNA 2016

Abstract Archives of the RSNA, 2016


SST08-05

Optimized Image Acquisition and Leakage Correction Post-Processing of Dynamic Susceptibility Contrast (DSC) MRI for Highest Accuracy of Relative Cerebral Blood Volume (rCBV) Quantification in Human Brain Tumors

Friday, Dec. 2 11:10AM - 11:20AM Room: E353A



Kevin Leu, Los Angeles, CA (Presenter) Nothing to Disclose
Jerrold L. Boxerman, MD, PhD, Providence, RI (Abstract Co-Author) Medical Advisor, Imaging Biometrics, LLC
Benjamin M. Ellingson, MS, PhD, Los Angeles, CA (Abstract Co-Author) Research Consultant, MedQIA Imaging Core Laboratory Research Consultant, F. Hoffmann-La Roche Ltd Research Consultant, Tocagen Inc Research Consultant, Boston Scientific Corporation Research Consultant, Amgen Inc Research Grant, Siemens AG Research Grant, F. Hoffmann-La Roche Ltd
PURPOSE

Various strategies have been employed to combat T1 or T2* leakage artifacts resulting from contrast agent extravasation in brain tumors, including adjusting the flip angle, use of a preload, and diverse post-processing leakage correction algorithms. The current study uses DSC simulations and experimental testing to optimize the image acquisition parameters and leakage correction algorithms to obtain rCBV measurements with the highest accuracy.

METHOD AND MATERIALS

DSC data was simulated using developments from Quarles et al.(1). Flip angle, TE, TR, and preload dosages were varied to simulate various MRI protocols.  Monte Carlo simulation of 100 tumors, with varying Ktrans, ve, and T10, was used to test each protocol. Uncorrected rCBV, unidirectional leakage correction, and bidirectional leakage correction(2) estimates were compared to a gold standard (tumor without contrast extravasation).

RESULTS

Low flip angles, high TE, high TR, and preload dosage increase T2*-weighting.  The smaller the deviation of the uncorrected deltaR2* curve from the gold standard, as measured by uncorrected rCBV error, the smaller the residual error was after leakage correction. Furthermore, rCBV estimates with bidirectional correction had lower percentage error than those with unidirectional correction both with and without preload by a factor of 2.0±0.2. Optimal protocols had flip angle 60 degrees with TE = 35 ms, TR ranging from 1.5-2 s, and preload dosage varying from 0 to ½, with the DSC-MRI injection using the remaining portion of a full dose.  

CONCLUSION

Results suggest that the best performance occurs when the acquisition protocol yields approximately equal T1 and T2* contributions from contrast agent extravasation, rather than a DSC-MRI signal with dominant T1- or T2*-weighting.  The bidirectional rCBV estimates consistently outperform the unidirectional and uncorrected rCBV estimates.

CLINICAL RELEVANCE/APPLICATION

Clinical trials using DSC-MRI perfusion should focus on using protocols that minimize errors for the uncorrected rCBV to best recover “true” rCBV.1) Quarles et al., Phys Med Biol, 2009; 2) Leu et al., JMRI, 2016