Neuroimaging clinics of North America
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Paragangliomas of the head and neck are rare vascular skull-base tumors derived from the paraganglionic system with an estimated incidence of 1:30,000 accounting for 3% of all paragangliomas. The most common paraganglioma locations of the head and neck in descending order are the carotid body, jugular, tympanic, and vagal paragangliomas. This article discusses the clinical characterics, normal anatamy, imaging findings and protocols, pathology, staging, and differential diagnosis for paragangliomas of the head and neck.
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Neuroimaging Clin. N. Am. · May 2016
ReviewVenous Abnormalities Leading to Tinnitus: Imaging Evaluation.
Venous anomalies are the most commonly identified abnormality by imaging in the work-up for pulse synchronous tinnitus. Potential diagnoses include idiopathic intracranial hypertension, sigmoid sinus wall anomalies, transverse and sigmoid sinus stenosis, jugular bulb anomalies, and prominent posterior fossa emissary veins. These causes are discussed in detail along with the association between sigmoid sinus wall anomalies and idiopathic intracranial hypertension.
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Tinnitus is a common symptom that usually originates in the middle ear. Vascular causes of pulsatile tinnitus are categorized by the location of the source of the noise within the cerebral-cervical vasculature: arterial, arteriovenous, and venous. Arterial stenosis secondary to atherosclerotic disease or dissection, arterial anatomic variants at the skull base, and vascular skull base tumors are some of the more common causes of arterial and arteriovenous pulsatile tinnitus. Noninvasive imaging is indicated to evaluate for possible causes of pulsatile tinnitus, and should be followed by catheter angiography if there is a strong clinical suspicion for a dural arteriovenous fistula.
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Tinnitus is a consequence of changes in auditory and nonauditory neural networks following damage to the cochlea. Homeostatic compensatory mechanisms occur after hearing loss and these mechanisms alter the balance of excitatory and inhibitory neurotransmitters. ⋯ When auditory network dysfunction is coupled with limbic-gating dysfunction, an otherwise meaningless auditory percept such as tinnitus may acquire negative emotional features. The development of effective treatment options is enhanced by the understanding of the neural networks underpinning tinnitus.