Effects of temporal resolution on blood-brain barrier permeability measurement with Dynamic Contrast Enhanced MRI in multiple sclerosis enhancing lesions

Discussion: Experimental data and simulations show that the temporal resolution of the acquisition during the first pass bolus has an important impact on (Ktrans, ve) estimates in the lesions, even though the contrast uptake in the lesions occurs at a later time. The associated changes were quantitatively consistent between experimental data and simulation. Simulations show that an acquisition at 5 s resolution for the first 50 s provides accurate estimates of BBB permeability over the range of Ktrans encountered in MS enhancing lesions. Acquiring at a 32 s resolution throughout results in accurate Ktrans estimates in slowly enhancing lesions (Ktrans ≤ 0.02 min -1 ), but provides systematic overestimates at higher permeability values, up to 12% in the case illustrated in Figure 2. Acquisitions at a resolution of 64 s or lower, found in literature (5) , result in much poorer accuracy and precision, despite the gain in SNR. The "dual-temporal resolution" acquisition method therefore yielded encouraging results: good accuracy in BBB permeability estimates was achieved over a wide range of potential values, with no cost in terms of SNR and spatial resolution. The study is on-going and analysis in a larger pool of enhancing lesions should allow full experimental validation of the method.