Its sensitivity for contrast leakage from the subarachnoid space into the sinonasal or tympanomastoid cavities depends on the rate of CSF leak and ranges between 85% and 92% in patients with an active leak versus 40% in patients with an inactive or intermittent leak [64]. Noninvasive noncontrast HRCT has a high sensitivity of 84% to 95% and has replaced traditional use of minimally invasive contrast-enhanced CT cisternography in the initial imaging evaluation of suspected CSF leak with laboratory confirmation [64,65]. No additional preoperative neuroimaging is necessary when a single skull base defect is identified on the HRCT; when there are multiple potential CSF leak sites, then follow-up CT cisternography is indicated [58,64]. Head Trauma FDG-PET/CT Brain There is no relevant literature to support the use of FDG-PET/CT in the initial imaging evaluation of suspected CSF leak. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of SPECT in the initial imaging evaluation of suspected CSF leak. MR Spectroscopy Head There is no relevant literature to support the use of MRS in the initial imaging evaluation of suspected CSF leak. MRI Functional (fMRI) Head There is no relevant literature to support the use of fMRI in the initial imaging evaluation of suspected CSF leak. MRI Head MR cisternography is the use of high-resolution T2-weighted or steady-state free precession sequences to look for CSF communication or meningoencephalocele across a defect in the skull base. It is a second-line noninvasive imaging option in the setting of suspected CSF leak with laboratory confirmation that has a reported accuracy of 89% and sensitivity of 87%, which is lower than HRCT [66]. It may be useful as a follow-up study when there is a suspected meningoencephalocele on HRCT (eg, soft-tissue mass with bone erosion) or when preoperative HRCT is unable to pinpoint a single osseous defect in the skull base.
Head Trauma PCAs. Its sensitivity for contrast leakage from the subarachnoid space into the sinonasal or tympanomastoid cavities depends on the rate of CSF leak and ranges between 85% and 92% in patients with an active leak versus 40% in patients with an inactive or intermittent leak [64]. Noninvasive noncontrast HRCT has a high sensitivity of 84% to 95% and has replaced traditional use of minimally invasive contrast-enhanced CT cisternography in the initial imaging evaluation of suspected CSF leak with laboratory confirmation [64,65]. No additional preoperative neuroimaging is necessary when a single skull base defect is identified on the HRCT; when there are multiple potential CSF leak sites, then follow-up CT cisternography is indicated [58,64]. Head Trauma FDG-PET/CT Brain There is no relevant literature to support the use of FDG-PET/CT in the initial imaging evaluation of suspected CSF leak. HMPAO SPECT or SPECT/CT Brain There is no relevant literature to support the use of SPECT in the initial imaging evaluation of suspected CSF leak. MR Spectroscopy Head There is no relevant literature to support the use of MRS in the initial imaging evaluation of suspected CSF leak. MRI Functional (fMRI) Head There is no relevant literature to support the use of fMRI in the initial imaging evaluation of suspected CSF leak. MRI Head MR cisternography is the use of high-resolution T2-weighted or steady-state free precession sequences to look for CSF communication or meningoencephalocele across a defect in the skull base. It is a second-line noninvasive imaging option in the setting of suspected CSF leak with laboratory confirmation that has a reported accuracy of 89% and sensitivity of 87%, which is lower than HRCT [66]. It may be useful as a follow-up study when there is a suspected meningoencephalocele on HRCT (eg, soft-tissue mass with bone erosion) or when preoperative HRCT is unable to pinpoint a single osseous defect in the skull base.