Imaging
MRI was performed using a 3T Achieva MR system (Philips
Healthcare, Cleveland, OH) with an 8-channel Sense head coil.
The protocol included a transverse 3D T -weighted (T w) volumet-
ric isotropically reconstructed turbo spin echo Acquisition (VIRTA)
sequence,13 before and after (83% of patients) contrast administration,
and a time-of-flight magnetic resonance angiography (TOF-MRA)