Susceptibility-based analysis of dynamic gadolinium bolus perfusion MRI

Purpose: An algorithm is developed for the reconstruction of dynamic, gadolinium (Gd) bolus MR perfusion images of the human brain, based on quantitative susceptibility mapping (QSM). Methods: The method is evaluated in five perfusion scans obtained from four different patients scanned at 3 Tesla, and compared with the conventional analysis based on changes in the transverse relaxation rate ΔR₂∗ and to theoretical predictions. QSM images were referenced to ventricular cerebrospinal fluid (CSF) for each dynamic of the perfusion sequence. Results: Images of cerebral blood flow and blood volume were successfully reconstructed from the QSM-analysis, and were comparable to those reconstructed using ΔR₂∗. The magnitudes of the Gd-associated susceptibility effects in gray and white matter were consistent with theoretical predictions. Conclusion: QSM-based analysis may have some theoretical advantages compared with DR2∗, including a simpler relationship between signal change and Gd concentration. However, disadvantages are its much lower contrast-to-noise ratio, artifacts due to respiration and other effects, and more complicated reconstruction methods. More work is required to optimize data acquisition protocols for QSM-based perfusion imaging.