Neuroimaging clinics of North America
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Neuroimaging Clin. N. Am. · Nov 2021
ReviewNew and Advanced Magnetic Resonance Imaging Diagnostic Imaging Techniques in the Evaluation of Cranial Nerves and the Skull Base.
The skull base and cranial nerves are technically challenging to evaluate using magnetic resonance (MR) imaging, owing to a combination of anatomic complexity and artifacts. However, improvements in hardware, software and sequence development seek to address these challenges. This section will discuss cranial nerve imaging, with particular attention to the techniques, applications and limitations of MR neurography, diffusion tensor imaging and tractography. Advanced MR imaging techniques for skull base pathology will also be discussed, including diffusion-weighted imaging, perfusion and permeability imaging, with a particular focus on practical applications.
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Neuroimaging Clin. N. Am. · Nov 2021
ReviewImaging of Acquired Skull Base Cerebrospinal Fluid Leaks.
Acquired skull base cerebrospinal fluid (CSF) leaks can result from trauma, tumors, iatrogenic causes, or may be spontaneous. Spontaneous skull base CSF leaks are likely a manifestation of underlying idiopathic intracranial hypertension. ⋯ Imaging with high-resolution CT is performed to locate osseous defects, while high-resolution T2w MRI may detect CSF traversing the dura and bony skull base. When leaks are multiple or if samples of fluid cannot be obtained for testing, then recourse to invasive cisternography may be necessary.
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The sellar and parasellar region is complex, with a unique meningeal, neural, vascular, and bony anatomy. Understanding the imaging anatomy is critical for accurate imaging interpretation. resonance (MR) imaging is the primary modality for pituitary imaging, whereas computed tomography may be used when MR imaging is contraindicated, and provides complementary bony anatomic information. This article reviews embryology and anatomy of the sellar and parasellar region. Imaging appearances of pituitary adenomas, Rathke cleft cysts, meningiomas, craniopharyngiomas, arachnoid cysts, vascular disorders, infectious abnormalities, and pituitary apoplexy are discussed and illustrated.
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Neuroimaging Clin. N. Am. · Nov 2021
ReviewPatterns of Perineural Skull Base Tumor Extension from Extracranial Tumors.
Perineural extension is an increasingly recognized pathway of extension of cutaneous, mucosal, and salivary gland neoplasms associated with a severe adverse prognosis. Imaging identification is feasible by MR imaging 3-dimensional contrast-enhanced submillimetric sequences. ⋯ PET with computed tomography may aid in the identification of the primary tumor location or recognition of recurrence, but only in conjunction with MR imaging does it achieve similar detection rates for perineural extension. Computed tomography scanning is an adjunct to MR imaging to increase specificity and for surgical treatment planning.