Duplex US may be performed when there is a bruit in the neck and carotid stenosis is suspected. However, most other conditions which cause PT cannot be evaluated by US. US can also detect parameters of low flow resistance, high-flow velocity and high-flow volume in external carotid arteries in patients with suspected dAVF as a cause of PT [69]. However, sensitivity is lower than CTA, MRA, and conventional angiography. US Duplex Doppler Transcranial There is no relevant literature to support the use of US duplex Doppler transcranial for evaluation of PT when otoscopy does not show a vascular retrotympanic lesion. US Head There is no relevant literature to support the use of US head for evaluation of PT when otoscopy does not show a vascular retrotympanic lesion. Variant 2: Pulsatile tinnitus, unilateral or bilateral; suspected retrotympanic lesion on otoscopy. Initial imaging. PT has many causes, and no single imaging study is appropriate for all patients. A diagnostic algorithm based on detailed history and clinical evaluation should progress from less invasive to more invasive imaging studies, and a targeted history and clinical assessment can have implications on the choice of imaging modality [12,19]. Otoscopic examination is extremely useful to guide the correct imaging in evaluation of the PT. When a vascular retrotympanic lesion is seen, the main differential diagnoses are glomus tympanicum, glomus jugulotympanicum, and vascular variants like aberrant ICA, dehiscent jugular foramen, and persistent stapedial artery (PSA). Otosclerosis can also appear as a pinkish retrotympanic lesion (Schwartz sign). It is extremely important to diagnose the vascular variants because inadvertent biopsy can have devastating complications. High-resolution thin-section temporal bone CT (HRCT) without IV contrast has excellent accuracy to make these diagnoses by carefully evaluating the contour of the bone and air spaces. IV contrast is not necessary to diagnose these conditions.
Tinnitus. Duplex US may be performed when there is a bruit in the neck and carotid stenosis is suspected. However, most other conditions which cause PT cannot be evaluated by US. US can also detect parameters of low flow resistance, high-flow velocity and high-flow volume in external carotid arteries in patients with suspected dAVF as a cause of PT [69]. However, sensitivity is lower than CTA, MRA, and conventional angiography. US Duplex Doppler Transcranial There is no relevant literature to support the use of US duplex Doppler transcranial for evaluation of PT when otoscopy does not show a vascular retrotympanic lesion. US Head There is no relevant literature to support the use of US head for evaluation of PT when otoscopy does not show a vascular retrotympanic lesion. Variant 2: Pulsatile tinnitus, unilateral or bilateral; suspected retrotympanic lesion on otoscopy. Initial imaging. PT has many causes, and no single imaging study is appropriate for all patients. A diagnostic algorithm based on detailed history and clinical evaluation should progress from less invasive to more invasive imaging studies, and a targeted history and clinical assessment can have implications on the choice of imaging modality [12,19]. Otoscopic examination is extremely useful to guide the correct imaging in evaluation of the PT. When a vascular retrotympanic lesion is seen, the main differential diagnoses are glomus tympanicum, glomus jugulotympanicum, and vascular variants like aberrant ICA, dehiscent jugular foramen, and persistent stapedial artery (PSA). Otosclerosis can also appear as a pinkish retrotympanic lesion (Schwartz sign). It is extremely important to diagnose the vascular variants because inadvertent biopsy can have devastating complications. High-resolution thin-section temporal bone CT (HRCT) without IV contrast has excellent accuracy to make these diagnoses by carefully evaluating the contour of the bone and air spaces. IV contrast is not necessary to diagnose these conditions.