Identification of the Normal Jugular Foramen and Lower Cranial Nerve Anatomy: Contrast-Enhanced 3D Fast Imaging Employing Steady-State Acquisition MR Imaging

SUMMARY: Conventional imaging protocols are unable to visualize the intraforaminal/canalicular seg-ments of the lower cranial nerves (IX–XII). On the basis of previous successful demonstration of individual cranial nerves within the cavernous sinus by constructive interference in steady-state MR imaging, we describe the use of contrast-enhanced 3D fast imaging employing steady-state acquisition MR imaging to demonstrate normal in vivo intraforaminal and canalicular segments of cranial nerves IX–XII in 10 patients by using a standardized imaging protocol. The detection of individual cranial nerves in the intrafo-raminal portion of the jugular foramen and hypoglossal canal is useful in diagnostic imaging1; however, visualization by using conventionalMR imaging protocols does not provide adequate detail of individual nerves.2,3 Recently, contrast-enhanced 3D constructive interference in steady state (CISS) MR imaging has successfully demonstrated the trigeminal ganglion and its divisions and individual cranial nerves within the cavernous sinus.4,5 3D fast imaging employing steady-state acquisition (FIESTA) is a similar form of steady-state se