(Wednesday, 8/1/2018) 7:30 AM - 9:30 AM
Room: Room 202
Purpose: To use an anthropomorphic phantom device to quantify the absolute accuracy and precision of DCE-MRI measurements made using a continuous golden-angle radial k-space sampling trajectory, with under-sampled data reconstructed using parallel imaging combined with compressed sensing (PICS).
Methods: Ground truth tissue concentration-time curves (CTCs) and arterial input function (AIF) curve-shapes (based on patient data) were established in the phantom using a highly-precise optical imaging system. The ground truth curves were subsequently repeatedly measured using DCE-MRI (3T scanner (Achieva; Philips, Netherlands), 32-channel detector coil). A multi-slice 2D turbo-field-echo imaging sequence was employed, with a stack-of-stars golden-angle radial trajectory (TR/TE=10.5/1.6ms, α=38°, FOV=224x224x18mm³, voxels=1.75x1.75x6mm³). Each of the five intra-/inter-session experiments consisted of two measurements of the AIF and either the ‘tumor’ or ‘healthy’ CTC. B1+ maps were also acquired using a dual-steady-state sequence (TR1/TR2/TE=30ms/150ms/2ms,�α=60°) and used to correct for B1+ field non-uniformities. Data were reconstructed using the PICS approach at radial sampling densities (RSDs) ranging from 100% to 4.68%. Pharmacokinetic (PK) modeling was performed using a linear version of the standard Toft's model, with results compared against precisely known ground truth values.
Results: Data reconstructed at RSD=100% provided calculated PK parameters (Kᵗʳᵃ�ˢ, vₑ and kep) with all errors ≤2% and intra-/inter-session standard deviation ≤4%. Both accuracy and precision reduced with reduced RSD, however even at the lowest RSD tested (RSD=4.68%) all PK parameters were calculated with errors ≤12%, intra-session standard deviation ≤11%, and inter-session standard deviation ≤7%.
Conclusion: The data presented herein demonstrate that a continuous golden-angle radial k-space trajectory for data acquisition, combined with PICS image reconstruction, holds promise for improving the accuracy and precision of PK modeling of DCE-MRI data, even for highly-accelerated acquisitions. This knowledge of quantification errors may contribute towards the standardization of DCE-MRI acquisition protocols and hence to greater clinical adoption of the technique.
Funding Support, Disclosures, and Conflict of Interest: This work was funded by Irish Cancer Society Research Scholarship CRS13KNI supported by the Movember Foundation. M Clemence is an employee of Philips Healthcare UK.
Keywords
Quantitative Imaging, Validation, Phantoms
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