Fig 5. Increase of the tracts (FT_6d) after embolization (patient 6, DTI_6d). A 21-year-old woman with cervical spinal cord arteriovenous malformation first presented with a sudden tetraplegia when she was 12 years old. The neurologic status gradually improved (the McCormick score was grade I at the time of referral to our hospital). MR imaging, angiograms, fiber tracking before (A, C, and E) and after embolization (B, D, and F), and FA and ADC images (G and H) are shown.

At the level of the nidus (arrow), located within the cord, there was partial discontinuity of the tracts (E). Above and below the nidus, conventional T2-weighted images (A,B) showed a central cavity in the cord. Here, FT_6d showed both a global thinning of the beam (double arrow in E) and separated tracts around the central cavity. When we compared the evolution after embolization, angiography demonstrated decrease of flow inside the nidus and the draining veins (D). T2-weighted images did not show any modification of the appearance of the perinidal cord. The FT_6d showed (F) an increased number of tracts at the level (arrow) and just above (double arrow) the nidus, presumably due to a reduction of venous congestion with concomitant higher FA values and therefore better visualization of fiber tracts. Panels G and H demonstrate the FA values and the ADC map with the ROI placements (white areas) at 3 different levels.