Validity of Carotid Duplex Sonography in Screening for Intracranial Dural Arteriovenous Fistula among Patients with Pulsatile Tinnitus

Toward a Diagnostic Imaging Algorithm for Undifferentiated Pulsatile Tinnitus

OBJECTIVE

Decisions around the diagnostic evaluation for pulsatile tinnitus (PT) remain challenging. We describe the usage patterns and diagnostic accuracy of imaging modalities and propose an evidence-based diagnostic approach for undifferentiated PT.

STUDY DESIGN

Retrospective.

SETTING

Single otology/neurotology clinic.

SUBJECTS

Patients with PT presenting between 2009 and 2020.

MAIN OUTCOME MEASURES

Sensitivity, specificity, diagnostic yield, and diagnostic accuracy.

RESULTS

A total of 315 subjects met inclusion criteria (74% female, mean ± SD age = 52 ± 17 years). Subjects were divided into four cohorts based on exam findings: normal (n = 229), venous cohort (n = 34), arterial cohort (n = 16), and outer/middle ear pathology cohort (n = 40). In total, 53% of patients received a nonidiopathic diagnosis for PT. The most common identifiable cause was sigmoid sinus dehiscence (78%) in the venous cohort, carotid stenosis (36%) in the arterial cohort, and glomus tumor (56%) in the outer/middle ear pathology cohort. There was a higher diagnostic rate among patients with positive exam findings compared to those with unrevealing exams (p = 0.04). Imaging studies with the highest diagnostic yield were computed tomography (CT) venography (44%), formal angiography (42%), and magnetic resonance venography (40%); studies with the highest specificity were formal angiography (0.82), CT angiography (0.67), and CT venography (0.67). A diagnostic algorithm is proposed.

CONCLUSIONS

Reaching a diagnosis in patients with PT requires a systematic approach, taking into account both clinical and radiographic information. Physical examination is a key first step for differentiating patients into venous, arterial, and other cohorts to narrow down the likely pathology and determine which radiographic studies have the highest yield and accuracy.

Quantitative Analysis of Occipital Artery Bypass Donor Vessels by Ultrasonography and DSA

BACKGROUND

Occipital artery (OA) acts as a vital donor vessel in intra-cranialand extra-cranial bypass. Ultrasonography and digital subtracted angiography (DSA) are becoming increasingly important in the assessment of vascular morphology and hemodynamically; however, quantitative analysis of occipital artery bypass donor vessels by Ultrasonography and DSA are seldom discussed.

METHODS

A retrospective study involving 62 cases accepted occipital artery bypass to treat posterior circulation aneurysms or artery occlusion/stenosis. The characteristics of OA are collected and analyzed.

RESULTS

Occipital artery bypasses were performed to treat posterior circulation aneurysms in 34 patients and to treat posterior circulation artery occlusion or stenosis in 28 patients. Compared with the ultrasonography group, the DSA group had a greater diameter of OA, and Bland Altman analysis indicated that the discrepancy between the 2 groups was about 0.555 mm. Ultrasonography showed the characteristics of OA: the mean Peak Systolic Velocity (PSV) was 42.98 cm/s, the mean End Diastolic Velocity (EDV) was 8.811 cm/s, and the mean Resistance Index (RI) was 1.46. There were no statistical differences in the diameter of OA, PSV, EDV, and RI between the male group and female group, the elderly group and younger adult group or the left occipital artery group and right occipital artery group. However, compared with patients with posterior circulation aneurysms, patients with artery occlusion or stenosis were older and had higher PSV, RI, and greater diameter in occipital arteries. The mean diameter of occipital arteries was increased in the first postoperative years but reduced in 3 patients during 1 year follow-up.

CONCLUSIONS

Both ultrasonography and DSA were effective assessment methods of occipital artery bypasses, and the DSA group had a greater diameter of OA. Age, gender, and left or right sides had little effect on the diameter of OA, PSV, EDV, and RI. Posterior circulation occlusion or stenosis had higher PSV, RI, and greater diameter of the occipital artery when compared with posterior circulation aneurysms. Occipital artery bypasses could increase the diameter of OA in most cases.

Diagnostic Yield and Utility of Radiographic Imaging in the Evaluation of Pulsatile Tinnitus: A Systematic Review

Objective

The objective of this study is to assess diagnostic yield of imaging modalities used to evaluate patients presenting with pulsatile tinnitus (PT).

Databases Reviewed

PubMed, Embase, and Scopus were queried using the search terms "pulsatile tinnitus," "pulse-synchronous tinnitus," and "pulse synchronous tinnitus" with no date limitations.

Methods

Studies that reported diagnostic imaging for patients presenting with PT were included. Data were reviewed for sample size, gender, age, imaging study, indications, and diagnoses. The primary outcome measure from aggregated data was the yield of positive diagnoses made with each imaging modality. The quality of evidence was assessed for risk of bias.

Results

From an initial search of 1145 articles, 17 manuscripts met inclusion criteria, of which 12 studies evaluated individual imaging modalities. The number of unique patients included was 1232. The diagnostic yield varied between modalities: carotid ultrasound (21%, 95% confidence interval [CI]: 12%-35%), CT temporal bone (65%, CI: 20%-93%), computed tomographic angiography (86%, CI: 80%-90%), and MRI/magnetic resonance angiography (58%, CI: 43%-72%).

Conclusion

Studies on the diagnostic approach to PT are limited by heterogeneity in both inclusion criteria and reporting standards. A wide range of imaging modalities are used in practice during the initial evaluation of PT, and the diagnostic yield for imaging can be improved by utilizing more specific clinical indications.

Diagnostic Ultrasonography in Neurology

OBJECTIVE

Ultrasonography allows neurologists to complement clinical information with additional useful, easily acquired, real-time data. This article highlights its clinical applications in neurology.

LATEST DEVELOPMENTS

Diagnostic ultrasonography is expanding its applications with smaller and better devices. Most indications in neurology relate to cerebrovascular evaluations. Ultrasonography contributes to the etiologic evaluation and is helpful for hemodynamic diagnosis of brain or eye ischemia. It can accurately characterize cervical vascular atherosclerosis, dissection, vasculitis, or other rarer disorders. Ultrasonography can aid in the diagnosis of intracranial large vessel stenosis or occlusion and evaluation of collateral pathways and indirect hemodynamic signs of more proximal and distal pathology. Transcranial Doppler (TCD) is the most sensitive method for detecting paradoxical emboli from a systemic right-left shunt such as a patent foramen ovale. TCD is mandatory for sickle cell disease surveillance, guiding the timing for preventive transfusion. In subarachnoid hemorrhage, TCD is useful in monitoring vasospasm and adapting treatment. Some arteriovenous shunts can be detected by ultrasonography. Cerebral vasoregulation studies are another developing field of interest. TCD enables monitoring of hemodynamic changes related to intracranial hypertension and can diagnose cerebral circulatory arrest. Optic nerve sheath measurement and brain midline deviation are ultrasonography-detectable signs of intracranial hypertension. Most importantly, ultrasonography allows for easily repeated monitoring of evolving clinical conditions or during and after interventions.

ESSENTIAL POINTS

Diagnostic ultrasonography is an invaluable tool in neurology, used as an extension of the clinical examination. It helps diagnose and monitor many conditions, allowing for more data-driven and rapid treatment interventions.

Dual-phase contrast-enhanced CT evaluation of dural arteriovenous fistula in patients with pulsatile tinnitus as an initial symptom

PURPOSE

Intracranial dural arteriovenous fistula (DAVF) can cause pulsatile tinnitus (PT). The purpose of this study was to investigate the diagnostic performance of dual-phase contrast-enhanced CT (DP-CECT) for DAVF in PT patients compared with digital subtraction angiography (DSA).

METHOD

From February 2015 to April 2021, PT patients undergoing routine DSA examination were prospectively analyzed. Patients with and without DAVF diagnosed by DSA were included. In DP-CECT, the radiological signs related to DAVF were assessed as follows: asymmetric external carotid artery (ECA) branches, asymmetric enhancement of intracranial or extracranial veins, asymmetric venous collaterals in extracranial space, and shaggy tentorium or venous sinus on CTA; asymmetric enhancement of intracranial or extracranial veins on CTV; numerous transcalvarial channels and asymmetric size of foramen spinosum on high-resolution CT (HRCT).

RESULTS

253 PT patients receiving DSA were enrolled, and these patients had previously been screened by DP-CECT. Forty-six patients were diagnosed as DAVF by DSA. Therefore, the prevalence of DAVF was 18% (46/253) in patients with PT as the initial symptom. The sensitivity and specificity of DP-CECT for diagnosis of DAVF were 96% and 100%. The sensitivity of individual CTA signs ranged from 65% to 93%, and specificities ranged from 83% to 100%. The sensitivity of CTV sign was 80%, and specificity was 100%. The sensitivity of individual HRCT signs ranged from 48 to 52% and specificities from 61 to 100%.

CONCLUSIONS

DAVF is not rare in patients with PT as the initial symptom. DP-CECT can be used for screening DAVF in patients with PT.

Elevated end-diastolic ratio of the common carotid artery due to cerebral arteriovenous malformation: Two case reports

An elevated end-diastolic (ED) ratio of the common carotid artery (CCA) is an indicator of occlusive lesions of the distal portion of the internal carotid artery. We report 2 cases of cerebral arteriovenous malformation (AVM) showing an elevated ED ratio of the CCA, which decreased after surgery. Case 1 was a 28-year-old man with chronic recurrent headache with aura, and case 2 was a 29-year-old woman with sudden-onset headache and intracerebral hemorrhage without neurologic abnormality. In both cases, digital subtraction angiography revealed a Spetzler-Martin Grade IV AVM, which was mainly fed by branches of the left middle cerebral artery with venous drainage into superficial and deep cerebral veins. Preoperative carotid ultrasonography showed an elevated CCA ED ratio (1.38 in case 1 and 1.47 in case 2; left > right) without atherosclerotic lesions. Patients' AVMs were successfully resected. In both cases, the ED ratio was decreased after surgery (to 1.05 in case 1 and 1.20 in case 2). A decrease in vascular resistance on 1 side caused by cerebral AVM can result in an increase in the CCA ED ratio comparable to that of carotid axis occlusion.

Usefulness of end-diastolic ratio in carotid ultrasonography for the screening of dural arteriovenous fistula: a case series

We report three cases in which carotid ultrasonography was useful for the diagnosis of dural arteriovenous fistula (dAVF). In all cases, dAVFs were fed by branches of the external carotid artery (ECA) and had retrograde leptomeningeal venous drainage. Carotid ultrasonography revealed high end-diastolic ratio (ED ratio) of the common carotid artery (CCA) (1.49-2.16) and low resistance index (RI) of the ECA (0.59-0.66). They were normalized after endovascular treatment (ED ratio of CCA 1.02-1.06, RI of ECA 0.75-0.87). In conclusion, high ED ratio of the CCA and low RI of the ECA might be a useful indicator for both screening and follow-up of dAVF.

Pulsatile Tinnitus: Differential Diagnosis and Radiological Work-Up

PURPOSE OF REVIEW

Identification of the underlying cause of pulsatile tinnitus is important for treatment decision making and for prognosis estimation. For this, an adequate diagnostic imaging strategy is crucial.

RECENT FINDINGS

Both CT and MRI can be useful, and in general, these modalities provide complementary diagnostic information. The scanning protocol can be optimized based on the estimated a priori chance for finding specific pathology, or the need to rule out more rare but clinical significant disease. In recent years, dynamic CTA, also referred to as 4D-CTA, has become available as a new technique that enables non-invasive evaluation of hemodynamics for the detection, classification, and follow-up of vascular malformations.

SUMMARY

The value of different diagnostic imaging modalities in the work-up of pulsatile tinnitus is discussed in relation to the differential diagnosis. Furthermore, imaging findings of different diseases are presented, both for CT and MRI.

[A dural arteriovenous fistula detected during the chronic phase of cerebral venous sinus thrombosis]

A 47-year-old woman developed a headache and tinnitus in her right ear followed by sudden-onset left hemiparesis. She had no history of trauma or thrombophilia. Arteriography showed an occlusion of the superior sagittal sinus, and a stenosis of the right transverse sinus. She was treated with anticoagulants; thereafter her deficits and sinus thrombosis immediately improved. However, 7 months after the onset, she noticed tinnitus in her left ear. Arteriography showed a dural arteriovenous fistula extending from the left occipital artery to the left transverse and sigmoid sinus, but no recurrence of the cerebral venous sinus thrombosis. After manual compression of the left occipital artery was initiated, the tinnitus and dural arteriovenous fistula did not worsen. A dural arteriovenous fistula may be detected in patients with cerebral venous sinus thrombosis during the chronic phase.

Diagnosis and management of intracranial dural arteriovenous fistulas

Dural arteriovenous fistula (DAVF) is a rare type of acquired intracranial vascular malformation. Recent progress in neuroimaging technology, such as advanced MRI and CT, provides non-invasive methods to accurately diagnose DAVF, including evaluation of the hemodynamics of the drainage veins. The clinical manifestations of DAVFs vary widely and depend on the location and venous drainage pattern of arteriovenous shunting. Patients with high grade DAVFs having cortical venous reflux should receive aggressive treatment to prevent the occurrence of intracranial hemorrhage and other neurological deficits related to venous congestion. Intra-arterial or intravenous endovascular embolization remains the primary therapy for high grade DAVF, while open surgery and stereotactic radiosurgery can serve as alternative treatment options. Early and accurate diagnosis with appropriate treatment is the goal for clinical management of DAVFs to reduce symptoms and prevent the development of venous congestion and stroke.