PT has many causes, and no single imaging study is appropriate for all patients. A diagnostic algorithm based on a detailed history and clinical evaluation should progress from less invasive to more invasive imaging studies. The history and clinical assessment have implications on the choice of imaging modality [12,19]. For example, an otoscopic examination is extremely useful to help guide optimal imaging evaluation of PT. Tinnitus Sigmoid sinus wall dehiscence and sigmoid sinus diverticulum are collectively called sigmoid sinus wall abnormalities (SSWA) and are increasingly recognized causes of PT [19,25-27]. Structural and anatomic causes of PT can be found in up to 44% to 91% of patients; however, in some studies, many patients remained idiopathic even after extensive workup [28,29]. The history and physical examination may also suggest PT due to systemic causes such as pregnancy-related hemodynamic changes, anemia, thyrotoxicosis, or due to mechanical causes like palatal or tympanic myoclonus, Eustachian tube contractions, or temporomandibular joint problems [30-34]. Arteriography Cervicocerebral Arteriography is an invasive test, which can diagnose many conditions causing PT, and is used when noninvasive tests like CTA and MRA are inconclusive and there is persistent clinical suspicion for a vascular lesion. It is particularly useful for detecting dAVFs and other lesions with arteriovenous shunts such as AVM and carotid cavernous sinus fistulas [35]. These lesions may cause PT, and arteriography has a higher sensitivity and specificity than MRA or CTA, which are used for screening. Therefore, arteriography is still useful if CTA/MRA is negative but dAVF remains suspected to be the cause of PT [23,29]. It is also useful for preoperative planning and embolization for paragangliomas [36]. A study found an incidence of 24% for arteriovenous shunts in patients who were referred for digital subtraction angiography (DSA) for evaluation of PT.
Tinnitus. PT has many causes, and no single imaging study is appropriate for all patients. A diagnostic algorithm based on a detailed history and clinical evaluation should progress from less invasive to more invasive imaging studies. The history and clinical assessment have implications on the choice of imaging modality [12,19]. For example, an otoscopic examination is extremely useful to help guide optimal imaging evaluation of PT. Tinnitus Sigmoid sinus wall dehiscence and sigmoid sinus diverticulum are collectively called sigmoid sinus wall abnormalities (SSWA) and are increasingly recognized causes of PT [19,25-27]. Structural and anatomic causes of PT can be found in up to 44% to 91% of patients; however, in some studies, many patients remained idiopathic even after extensive workup [28,29]. The history and physical examination may also suggest PT due to systemic causes such as pregnancy-related hemodynamic changes, anemia, thyrotoxicosis, or due to mechanical causes like palatal or tympanic myoclonus, Eustachian tube contractions, or temporomandibular joint problems [30-34]. Arteriography Cervicocerebral Arteriography is an invasive test, which can diagnose many conditions causing PT, and is used when noninvasive tests like CTA and MRA are inconclusive and there is persistent clinical suspicion for a vascular lesion. It is particularly useful for detecting dAVFs and other lesions with arteriovenous shunts such as AVM and carotid cavernous sinus fistulas [35]. These lesions may cause PT, and arteriography has a higher sensitivity and specificity than MRA or CTA, which are used for screening. Therefore, arteriography is still useful if CTA/MRA is negative but dAVF remains suspected to be the cause of PT [23,29]. It is also useful for preoperative planning and embolization for paragangliomas [36]. A study found an incidence of 24% for arteriovenous shunts in patients who were referred for digital subtraction angiography (DSA) for evaluation of PT.