The primary limitation of CT cisternography is that the patient needs to have an active CSF leak at the time of this examination for the study to be potentially diagnostic. Studies comparing CT cisternography with MRI have demonstrated CT cisternography to have a lower sensitivity of 33% to 72% versus 67% to 93% for MRI with a heavily T2-weighted sequence (MR cisternogram) and 80% for contrast-enhanced MR cisternogram [13,59,60]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of sinonasal CSF leak. HRCT also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. HRCT can identify the skull base defect even in the absence of an active leak; however, it is limited in identifying a specific site of the leak if the patient has multiple osseous defects because it is not clear which defect is the source of the leak [12]. A combination of HRCT and MRI with a heavily T2-weighted sequence has a reported sensitivity of 90% to 96% [13,55,61]. HRCT alone is sufficient if only 1 osseous defect is identified and corresponds with the clinical symptoms [12]. HRCT may also be the only study required in patients with iatrogenic CSF leaks for preoperative planning, because the surgical site of leak is known [12]. There is no relevant literature to support the use of contrast-enhanced CT or combined pre- and postcontrast CT in the evaluation of CSF leak. CTA Head There is no relevant literature to support the use of CTA head in the evaluation of sinonasal CSF leak. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of sinonasal CSF leak. MRA Head There is no relevant literature to support the use of MRA head in the evaluation of sinonasal CSF leak.
Sinonasal Disease. The primary limitation of CT cisternography is that the patient needs to have an active CSF leak at the time of this examination for the study to be potentially diagnostic. Studies comparing CT cisternography with MRI have demonstrated CT cisternography to have a lower sensitivity of 33% to 72% versus 67% to 93% for MRI with a heavily T2-weighted sequence (MR cisternogram) and 80% for contrast-enhanced MR cisternogram [13,59,60]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of sinonasal CSF leak. HRCT also enables surgical planning given its detailed depiction of sinonasal anatomy and can be used with surgical image-guidance systems when acquired with the appropriate protocol. HRCT can identify the skull base defect even in the absence of an active leak; however, it is limited in identifying a specific site of the leak if the patient has multiple osseous defects because it is not clear which defect is the source of the leak [12]. A combination of HRCT and MRI with a heavily T2-weighted sequence has a reported sensitivity of 90% to 96% [13,55,61]. HRCT alone is sufficient if only 1 osseous defect is identified and corresponds with the clinical symptoms [12]. HRCT may also be the only study required in patients with iatrogenic CSF leaks for preoperative planning, because the surgical site of leak is known [12]. There is no relevant literature to support the use of contrast-enhanced CT or combined pre- and postcontrast CT in the evaluation of CSF leak. CTA Head There is no relevant literature to support the use of CTA head in the evaluation of sinonasal CSF leak. FDG-PET/CT Skull Base to Mid-Thigh There is no relevant literature to support the use of FDG-PET/CT in the evaluation of sinonasal CSF leak. MRA Head There is no relevant literature to support the use of MRA head in the evaluation of sinonasal CSF leak.