MR-Cisternography with T2-Weighted Single-Shot Fast Spin Echo Sequence in the Diagnosis of a Spontaneous CSF Fistula of the Sphenoid Sinus Causing Massive Pneumocephalus.

A spontaneous CSF fistula of the sphenoid sinus was preoperatively diagnosed in a young woman presenting with massive pneumocephalus and rhinorrhea. Diagnosis was established by MR cisternography using a heavily T2-weighted 3D single-shot FSE sequence with half-Fourier analysis (3D-EXPRESS(®)), originally developed for imaging the inner ear. While unenhanced CT failed to detect the site of the fistula, MR permitted complete evaluation of the sellar/sphenoid region and tracked the CSF signal down to the nasal cavity.