thin slice CT with bone window is definitely investigation of choice for choice for looking for integrity of bony wall of sinus, delineating moulding or distortion by mass effect , however may not be appropriate for Investigation of CSF leak. During active phase of CSF leak CT Cisternography is definitely investigation of choice
In cases with intermittent CSF leak, presenting during non-active CSF leak, MRI may better in delineating soft tissue morphology an probable site of CSF leak.