Fig. 3 

Perivenous hyperenhancement is identified upon BBB opening. FUS target map shown on axial T2-weighted sequence A. Post-contrast T1-weighted image immediately after FUS intervention shows contrast material extravasation due to BBB opening focally at the precuneus targeted site B. Note heterogeneous enhancement pattern within the targeted zone C, with contrast predominating along perivenous spaces (PVS), and less intense contrast enhancement in the remainder of the treatment zone interstitial fluid space (ISF). Pre-contrast MRI at 24 h post FUS showed complete clearance of contrast tracer (not shown). Post-contrast T1-weighted images in the same patient at 24–48 h revealed venous permeabilization manifesting as linear and curvilinear contrast enhancement within the FUS-treated zone, however there was no longer enhancement within the remaining interstitial fluid space D–F. This venous permeabilization enhancement corresponded anatomically to intraparenchymal and extraparenchymal parietal venous architecture, shown on SWI images G. See Additional files 3, 4 for additional images