Sigmoid sinus diverticulum and pulsatile tinnitus: analysis of CT scans from 15 cases

Flow Analysis of Central Venous Outflow Tract: A New Approach to Understanding Pulse-Synchronous Tinnitus

OBJECTIVE

Pulse-synchronous tinnitus (PST) has been linked to multiple anatomical variants of the central venous outflow tract (CVOT) including sigmoid sinus (SS) dehiscence and diverticulum. This study investigates flow turbulence, pressure, and wall shear stress along the CVOT and proposes a mechanism that results in SS dehiscence and PST.

STUDY DESIGN

Case series.

SETTING

Tertiary Academic Center.

METHODS

Venous models were reconstructed from computed tomography scans of 3 patients with unilateral PST. Two models for each patient are obtained: a symptomatic and contralateral asymptomatic side. A turbulent model-enabled commercial flow solver was used to simulate the pulsatile blood flow over the cardiac cycle through the models. Fluid flow through the transverse and SS junction was analyzed to observe the velocity, pressure, turbulent kinetic energy (TKE), and shear stress over a simulated cardiac cycle.

RESULTS

Fluid flow on the symptomatic side showed increased vorticity in the presence of an SS diverticulum. Higher TKE with periodicity following the cardiac cycle was observed on the symptomatic side, and a sharp increase was observed if SS diverticulum was present. Shear stress was highest near the narrowest segments of the vessel. Pressure was observed to be lower on the symptomatic side at the transverse-SS junction for all 3 patients.

CONCLUSION

Computational fluid dynamics modeling of blood flow through the CVOT in PST suggests that low pressure may be the cause of dehiscence, and tinnitus may result from periodic increases in TKE.

Sigmoid sinus diverticulum without pulsatile tinnitus occurring concurrently with chronic otitis media mucosal type

Sigmoid sinus diverticulum is a rare vascular anomaly often associated with pulsatile tinnitus. It can occur in cases of chronic otitis media squamous type (unsafe type) due to dehiscence of the sigmoid sinus plate caused by cholesteatoma. The presentation of which is that of pulsatile tinnitus. However, we present an unusual case of sigmoid sinus diverticulum occurring concurrently with chronic otitis media mucosal type (safe type) but in the absence of pulsatile tinnitus. This case report highlights the diagnostic challenges and management of this rare clinical scenario.

ACR Appropriateness Criteria® Tinnitus: 2023 Update

Tinnitus is abnormal perception of sound and has many subtypes. Clinical evaluation, audiometry, and otoscopy should be performed before ordering any imaging, as the choice of imaging will depend on various factors. Type of tinnitus (pulsatile or nonpulsatile) and otoscopy findings of a vascular retrotympanic lesion are key determinants to guide the choice of imaging studies. High-resolution CT temporal bone is an excellent tool to detect glomus tumors, abnormal course of vessels, and some other abnormalities when a vascular retrotympanic lesion is seen on otoscopy. CTA or a combination of MR and MRA/MRV are used to evaluate arterial or venous abnormalities like dural arteriovenous fistula, arteriovenous malformation, carotid stenosis, dural sinus stenosis, and bony abnormalities like sigmoid sinus wall abnormalities in cases of pulsatile tinnitus without a vascular retrotympanic lesion. MR of the brain is excellent in detecting mass lesions such as vestibular schwannomas in cases of unilateral nonpulsatile tinnitus. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Dynamic Volume Computed Tomography for Characterizing Pulsatile Tinnitus Caused by Sigmoid Sinus Diverticulum with Bone Defects: Clinical Implications

OBJECTIVE

The objective of this study is to investigate the diagnosis of dynamic volume computed tomography (CT) for pulsatile tinnitus caused by sigmoid sinus diverticulum (SSD) and bone defects.

METHODS

Data obtained by dynamic volume CT from 35 patients with SSD were retrospectively collected. Then the ear morphological parameters, including bone defect, transverse sinus stenosis, position of the jugular bulb, jugular bulb diverticulum, defect of the jugular bulb wall, gross venous sinus thrombosis and SSD, and blood perfusion parameters, including cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT), were evaluated and compared between the tinnitus side and the asymptomatic side of the ear.

RESULTS

The maximum diameters of the bone defects on the tinnitus side were greater than those on the asymptomatic side (Horizontal 6.36±2.35mm vs. 1.12±0.78mm; Longitudinal 4.87±1.25 vs. 0.88±0.06mm). Dynamic volume CT visually displayed the SSD herniated into the adjacent mastoid via the bone defect. Transverse sinus stenosis, high position of the jugular bulb, jugular bulb diverticulum, defect of the jugular bulb wall, and gross venous sinus thrombosis were present more frequently on the tinnitus side than on the asymptomatic side (P < 0.05). Moreover, CBF, CBV, and MTT were significantly greater on the tinnitus side than on the asymptomatic side (P < 0.05).

CONCLUSION

Dynamic volume CT examination is an effective method for the diagnosis of pulsatile tinnitus caused by SSD with bone defects.

State of the Art: Venous Causes of Pulsatile Tinnitus and Diagnostic Considerations Guiding Endovascular Therapy

Venous variants and pathologic abnormalities are the most common causes of pulsatile tinnitus. These conditions include causes of turbulence within normally located veins and sinuses, and abnormally enlarged or abnormally located veins in close transmissive proximity to the conductive auditory pathway. Such disorders include pathologic abnormalities of the lateral sinus (transverse sinus stenosis and sigmoid sinus wall anomalies), abnormalities and variants of the emissary veins, and anomalies of the jugular bulb and jugular vein. Despite being the most common causes for pulsatile tinnitus, venous variants and pathologic abnormalities are often overlooked in the workup of pulsatile tinnitus. Such oversights can result in delayed patient care and prolonged patient discomfort. Advances in both cerebrovascular imaging and endovascular techniques allow for improved diagnostic accuracy and an increasing range of endovascular therapeutic options to address pulsatile tinnitus. This review illustrates the venous causes of pulsatile tinnitus and demonstrates the associated endovascular treatment. © RSNA, 2021.

Detecting causes of pulsatile tinnitus on CT arteriography-venography: A pictorial review

Pulsatile tinnitus (PT) can be a mild or debilitating symptom. Following clinical examination and otoscopy, when the underlying aetiology is not apparent, radiological imaging can be used to evaluate further. CT arteriography-venography (CT A-V) of the head and neck has recently been introduced as a single 'one catch' modality for identifying the many causes of PT including those which are treatable and potentially serious whilst also providing reassurance through negative studies or studies with benign findings. CT A-V is performed as a single phase study allowing both arterial and venous assessment, hence limiting radiation exposure. Additional multiplanar reformats and bone reconstructions are desirable. Understanding the limitations of CT A-V is also required, with an awareness of the scenarios where other imaging modalities should be considered. The causes of PT can be divided into systemic and non-systemic categories. Non-systemic aetiologies in the head and neck should be carefully reviewed on CT A-V and include a variety of vascular causes (arteriovenous malformations/fistulas, venous or arterial aetiologies) and non-vascular causes (tumours and bony dysplasias). Venous causes (dominant, aberrant, stenosed or thrombosed venous vessels) are more common than arterial aetiologies (aberrant or stenosed internal carotid artery, aneurysms or a persistent stapedial artery). Glomus tumours that are not visible on otoscopy and osseous pathologies such as bony dehiscence and otospongiosis should also be excluded. Careful assessment of all the potential vascular and non-vascular causes should be reviewed in a systematic approach, with correlation made with the clinical history. A structured reporting template for the reporting radiologist is provided in this review to ensure all the potential causes of PT are considered on a CT A-V study. This will help in providing a comprehensive radiological evaluation, hence justifying the radiation dose and for patient assessment and prognostication.

Hemodynamic Changes in the Sigmoid Sinus of Patients With Pulsatile Tinnitus Induced by Sigmoid Sinus Wall Anomalies

OBJECTIVE

This study is to investigate the hemodynamic changes of pulsatile tinnitus (PT) patients induced by sigmoid sinus wall anomalies (SSWA).

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral university hospital.

PATIENTS

Fifteen unilateral PT patients with SSWA identified on computed tomography images and surgery and 15 age-, sex-, and body mass index-matched healthy volunteers underwent velocity-encoded, cine magnetic resonance imaging.

INTERVENTION

Hemodynamic data in sigmoid sinus were obtained from velocity-encoded, cine magnetic resonance imaging, and compared between PT patients and controls.

MAIN OUTCOME MEASURES

Heart rate was recorded. Cross-sectional area (CSA), peak positive velocity (PPV), average positive flow volume per beat (APFV/beat), average flow volume per beat (AFV/beat), peak negative velocity (PNV), and average negative flow volume per beat (ANFV/beat) were measured. Average flow volume per minute (AFV/min), average positive flow volume per minute (APFV/min), average negative flow volume per minute (ANFV/min), average positive velocity (APV), average negative velocity (ANV), and regurgitation fraction (RF) were calculated.

RESULTS

APV at PT side of patients was 13.4 ± 3.3 cm/s, which was significantly slower than that at corresponding side of controls (15.8 ± 2.6 cm/s). PNV and RF at PT side of patients were 21.0 ± 15.4 cm/s and 2.4% respectively, which were significantly higher than those values at corresponding side of controls (both of them were 0). HR, CSA, PPV, APFV/beat, APFV/min, AFV/beat, AFV/min, ANV, ANFV/beat, and ANFV/min were 69.8 ± 9.4 beat/min, 48.4 ± 17 mm, 31.4 ± 5.9 cm/s, 5.4 ± 1.8 ml/beat, 373.9 ± 117.7 ml/min, 5.1 ± 2.0 ml/beat, 352.0 ± 134.6 ml/min, 2 (0-4.9) cm/s, 1 (0-2.7) ml/beat, and 4.1 (0-141.3) ml/min at PT side of patients, and 67.4 ± 7.8 beat/min, 38.2 ± 18 mm, 29.9 ± 3.9 cm/s, 5.3 ± 2.0 ml/beat, 350.3 ± 125.3 ml/min, 5.1 ± 1.9 ml/beat, 340.5 ± 117.9 ml/min, 0 (0-2.1) cm/s, 0 (0-0.8) ml/beat, and 0 (0-55.4) ml/min at corresponding side of controls. These hemodynamics were not significantly different between groups.

CONCLUSION

APV, PNV, and RF changes take place in SSWA patients, which may be associated with the occurrence of PT and have the potential value to improve accurate etiological diagnosis and predict treatment success.

Prevalence of Sigmoid Sinus Dehiscence and Diverticulum among Adults with Skull Base Cephaloceles

BACKGROUND AND PURPOSE

Cephaloceles are relatively rare conditions caused by a congenital and/or acquired skull defect. The incidence of associated venous brain anomalies with regard to cephaloceles remains to be fully elucidated. Accordingly, we sought to assess the prevalence of sigmoid sinus dehiscence and diverticula in patients with spontaneous skull base cephaloceles.

MATERIALS AND METHODS

Our institutional data base was retrospectively queried from 2005 to 2018. Patients in whom spontaneous skull base cephaloceles were identified were ultimately included in the study cohort. These patients subsequently had their sigmoid sinuses re-evaluated with focused attention on the possible presence of dehiscence and/or diverticula.

RESULTS

We identified 56 patients: 12 men and 44 women. After re-evaluation of the sigmoid sinuses, evidence of dehiscence and/or diverticula was noted in 21 patients. The right sigmoid sinus was involved in 11 patients, and the left sigmoid sinus was involved in 7 patients, including 3 cases of diverticulum. In 3 patients, evidence of bilateral sigmoid sinus dehiscence and diverticula was noted. Female sex was associated with sigmoid sinus dehiscence and diverticula by univariate analysis (P = .019). By linear regression, cephalocele volume was negatively associated with sigmoid sinus dehiscence and diverticula (coefficient, -2266, P value < .007, adjusted R ² = 0.1077). By univariate logistic regression using average cephalocele volume as a cutoff, we demonstrate a statistically significant finding of lower volumes being associated with sigmoid sinus dehiscence and diverticula with an odds ratio of 3.58 (P = .05).

CONCLUSIONS

The prevalence of sigmoid sinus dehiscence and diverticula in patients with cephalocele is high. Female sex is associated with sigmoid sinus dehiscence and diverticula. The cephalocele volume appears to be inversely proportional to sigmoid sinus dehiscence and diverticula.

Treatment of pulsatile tinnitus caused by anomalies of the sigmoid sinus wall via combined internal and external sigmoid sinus wall reconstruction with 3D temporal bone CT guidance

PURPOSE

The present analysis aims to describe a surgical approach wherein pulsatile tinnitus (PT) arising due to sigmoid sinus wall anomalies (SSWA) can be treated via combination internal and external sigmoid sinus wall reconstruction. We further evaluated the utility of temporal bone 3D-CT imaging during both the pre- and post-operative assessments of all treated patients.

METHODS

Data pertaining to 11 patients that had undergone sigmoid sinus wall reconstruction were retrospectively analyzed. All of these patients underwent preoperative 3D-CT imaging assessment. These patients were additionally subjected to sigmoid sinus wall reconstruction via a combined internal and external layer approach. Postoperatively, all patients underwent a radiological assessment of auricular cartilage and autologous bone powered displacement. Patients were additionally asked about any subjective changes in PT or associated symptoms at follow-up time points.

RESULTS

SSWA in the 3D-CT imaging from these patients were all distinct. In 10/11 patients, PT fully resolved following reconstruction of the sinus wall. The remaining patients exhibited significant improvements in symptoms postoperatively, with PT fully resolving within a 1-month follow-up period. No patients suffered any major complications.

CONCLUSIONS

Temporal bone 3D-CT imaging allow for effective visualization of SSWA, enabling effective pre- and post-operative assessments of treated patients. A combined internal and external layer approach to sigmoid sinus wall reconstruction can be implemented safely and effectively, yielding high rates of satisfactory outcomes and achieving rigid reconstruction of this surface. As such, there is clear value in the consideration of this approach when treating individuals suffering from PT as a result of SSWA.

Sound Measurement in Patient-Specific 3D Printed Bench Models of Venous Pulsatile Tinnitus

HYPOTHESIS

We hypothesize patient-specific flow models to be an adequate in vitro surrogate to allow for characterization of pulsatile tinnitus (PT) that affects three to five million Americans.

BACKGROUND

PT, rhythmic sounds without an extracorporeal source that patients appreciate, can be caused by aberrant blood flow in large cerebral veins near the cochlea. To investigate the sound production mechanism, we created 3D printed flow models based on patient-specific cerebral venous anatomies.

METHODS

Magnetic resonance angiography datasets from two patients with PT were used to generate patient-specific 3D printed flow models. A flow circuit connecting the patient-specific models to a pulsatile, continuous flow pump simulating cardiac cycle was created. Sound recordings were made along the surface of the models using an electronic stethoscope. Peak-to-rms amplitude, and area under the power spectral density (PSD) curve values were computed to evaluate the sound measurements. Wilcoxon rank sum test was used to statistically determine the differences in measurements between the patient-specific models.

RESULTS

In patient-1, the recordings (peak-to-rms) from the internal jugular vein stenosis of baseline model (4.29 ± 1.26 for 146 samples) were significantly louder (p < 0.001) than that of the altered model (3.29 ± 0.96 for 143 samples). In patient-2, the sound measured at the transverse sinus stenosis in the pre-lumbar puncture model (4.84 ± 1.11 for 148 samples) was significantly louder (p < 0.0001) than that of the post-lumbar puncture model (3.14 ± 0.87 for 135 samples).

CONCLUSIONS

The models are able to generate sounds very similar to those appreciated by patients and examiners in the cases of objective PT.

A study on relationship between pulsatile tinnitus and temporal bone pneumatization grade

Pulsatile tinnitus (PT) is a common symptom in otology. In some cases, the venous flow in the sigmoid sinus (SS) is the source of PT. It is suggested that the venous sound is propagated into the tympanic cavity through the air pathway of temporal bone air cells (TBAC). The hyperpneumatization of TBAC was hypothesized as a direct pathology of PT through amplifying the venous sound, but there is no quantitative analysis. This study aims to quantify the relationship between the venous sound amplification and the pneumatization grade of TBAC. The acoustic numerical simulation and statistical analysis were performed based on the radiology data of 21 pulsatile tinnitus patients. The TBAC of these patients were classified into hypopneumatization, normal pneumatization and hyperpneumatization grades according to three standards. The in vitro acoustic experiment was done as the validation of simulation. It is indicated that the SS standard is effective for the clinical evaluation of venous sound amplification. The TBAC amplifies the venous sound due to the acoustic resonance at the first mode frequency, regardless of the pneumatization grades. The normal pneumatic TBAC exhibits the highest sound amplification effect on the venous sound amongst the three grades, contributing mostly to PT, but would not induce PT without any other causes.

An in vitro experimental study on the relationship between pulsatile tinnitus and the dehiscence/thinness of sigmoid sinus cortical plate

Pulsatile tinnitus (PT), characterized as pulse-synchronous, is generally objective. Sigmoid sinus (SS) venous sound is widely suggested to be a possible sound source of PT. The dehiscence and thinness of SS cortical plate (CP) was commonly reported as PT pathology in previous studies, but lack quantitative or biomechanical analysis. In this study, it was aimed to quantify the relationship between venous sound and CP dehiscence/thinness using in vitro experiment. The in vitro models of SS and CP were established based on 3D-printing, with the developed pulsatile venous flow in the SS model. The generated sound signal and the vibration response at the dehiscent/thinned area were analyzed. The sound signal generated in the normal-sized dehiscence model was pulse-synchronous within 100--400 Hz, which had similar acoustic characteristics as the clinical PT sounds. It was concluded that the pulsatile venous sound is produced at TS-SS junction in case of CP dehiscence. The CP, even a thinned one can effectively diminish the venous sound and sound-generating pulsatile vibration at TS-SS junction. The CP dehiscence would induce pulse-synchronous and high pressure venous sound, as well as pulse-synchronous vibration above 20 Hz, regardless of the dehiscence size. On the contrary, the CP thinness would not induce obvious venous sound or pulsatile vibration above 20 Hz.

Temporal bone contrast-enhanced high-resolution CT evaluation of pulsatile tinnitus after sigmoid sinus wall reconstruction

BACKGROUND

Sigmoid sinus wall reconstruction (SSWR) is a proven effective treatment for pulsatile tinnitus (PT) caused by sigmoid sinus wall dehiscence (SSWD) with or without sigmoid sinus diverticulum (SSD); however, comprehensive analysis of the postoperative imaging manifestations has not yet been reported.

PURPOSE

To analyze temporal bone computed tomography (CT) imaging features following SSWR in patients with PT.

MATERIAL AND METHODS

Following SSWR, temporal bone contrast-enhanced high-resolution CT (HRCT) images from 33 PT cases were retrospectively analyzed. Patients were divided into two groups based on follow-up interval: a short-interval group (≤18 months, 12 cases) and a long-interval group (>18 months, 21 cases). The mending material density and morphology was analyzed. Postoperative changes of the venous sinus were evaluated. Imaging manifestations of the normal temporal bone and mastoid air cells adjacent to the operative field were observed.

RESULTS

The order of CT values of mending materials was significantly lower in the short-interval group than in the long-interval group (Z = -4.716, P < 0.001); the incidence of complete newly remodeled cortical bone on the rim of the mending materials was significantly higher in the long-interval group than in the short-interval group ( P < 0.001). Eleven patients (33.3%) showed varying degrees of remnant SSWD. The mending materials and normal mastoid bone structure showed complete fusion (n = 12, 36.4%), partial fusion (n = 16, 48.5%), or complete separation (n = 5, 15.2%).

CONCLUSION

Temporal bone contrast-enhanced HRCT can be used to observe imaging features of the mending materials, venous sinus, adjacent normal temporal bone and mastoid air cells following SSWR.

MR Venous Flow in Sigmoid Sinus Diverticulum

BACKGROUND AND PURPOSE

Case reports demonstrate that coiling of a sigmoid sinus diverticulum can treat pulsatile tinnitus. We hypothesized that MR imaging 4D flow and computational fluid dynamics would reveal distinct blood flow patterns in the venous outflow tract in these patients.

MATERIALS AND METHODS

Patients with pulsatile tinnitus of suspected venous etiology underwent MR imaging at 3T, using venous phase contrast-enhanced MR angiography, 4D flow, and 2D phase contrast. The contrast-enhanced MRA contours were evaluated to determine the presence and extent of a sigmoid sinus diverticulum. Computational fluid dynamics analysis was performed using the 4D flow inlet flow and the luminal contours from contrast-enhanced MRA as boundary conditions. In addition, computational fluid dynamics was performed for the expected post treatment conditions by smoothing the venous geometry to exclude the sigmoid sinus diverticulum from the anatomic boundary conditions. Streamlines were generated from the 4D flow and computational fluid dynamics velocity maps, and flow patterns were examined for the presence of rotational components.

RESULTS

Twenty-five patients with pulsatile tinnitus of suspected venous etiology and 10 control subjects were enrolled. Five (20%) of the symptomatic subjects had sigmoid sinus diverticula, all associated with an upstream stenosis. In each of these patients, but none of the controls, a stenosis-related flow jet was directed toward the opening of the sigmoid sinus diverticulum with rotational flow patterns in the sigmoid sinus diverticulum and parent sigmoid sinus on both 4D flow and computational fluid dynamics.

CONCLUSIONS

Consistent patterns of blood flow can be visualized in a sigmoid sinus diverticulum and the parent sinus using 4D flow and computational fluid dynamics. Strong components of rotational blood flow were seen in subjects with sigmoid sinus diverticula that were absent in controls.

Hemodynamic assessments of venous pulsatile tinnitus using 4D-flow MRI

OBJECTIVE

To use 4D-flow MRI to characterize hemodynamics of transverse and sigmoid sinus in venous pulsatile tinnitus (PT) patients and to investigate their differences vs healthy controls.

METHODS

A total of 21 patients with venous PT and 11 healthy controls were included in the retrospective study. All participants underwent 4D-flow and magnetic resonance venography scan in a 3.0T magnetic resonance scanner. All visualization, quantification, and analysis of 4D-flow data were performed using dedicated software. Two independent reviewers evaluated the existence of vortex or turbulence. Covariance analysis adjusted for age was used to compare average through-plane velocity (V_{tp_avg}), maximum through-plane velocity (V_{tp_max}), average velocity (V_avg), maximum velocity (V_max), average blood flow (Flow_avg), and pulsatility index (PI) between PT and control group.

RESULTS

There were hemodynamic differences between PT patients and healthy controls. Compared with the control group, the PT group showed significantly higher V_{tp_avg}, V_{tp_max}, V_avg, V_max, and Flow_avg, and slightly higher PI. For the assessment of flow pattern, inter-reader reproducibility was excellent (κ = 1.00). Vortex or turbulence was observed in PT patients with good sensitivity (86.4%) and specificity (90.9%). Drainage dominance was more frequently observed in patients (15/21, 71.4%) than healthy controls (4/11, 36.4%).

CONCLUSIONS

Significant hemodynamic differences were found between venous PT patients and healthy controls with 4D-flow MRI. Hemodynamic conditions could serve as noninvasive biomarkers for diagnosis and treatment evaluation of venous PT.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that 4D-flow MRI accurately identifies patients with venous PT.

Evaluation and treatment of pulsatile tinnitus associated with sigmoid sinus wall anomalies

OBJECTIVE

Describe clinical and radiographic features of sigmoid sinus wall anomalies (SSWA) associated with pulsatile tinnitus (PT) and determine factors predictive of response to surgery.

METHODS

Preoperative diagnostic imaging and treatment response were reviewed after surgical repair of 40 ears among 38 consecutive patients presenting with PT associated with SSWA who underwent transtemporal sinus wall reconstruction.

RESULTS

Twenty-three ears had isolated sigmoid sinus dehiscence, and 17 had diverticulum. The rates of transverse sinus stenosis (TSS) and empty sella, 66% and 32% respectively, were significantly higher than in historical controls (P = 0.02 and 0.001). Thirty-six out of 40 subjects (90%) had complete resolution of their PT following surgery, including all those with a diverticulum. For subjects with dehiscence alone without diverticulum, a favorable response to surgery was strongly associated with the presence of TSS (P = 0.01) and empty sella (P = 0.02).

CONCLUSION

Sigmoid sinus diverticulum and dehiscence are a clinically important cause of PT. Women of childbearing age with an elevated body mass index (BMI) are commonly affected, and there is a high rate of associated TSS and empty sella. Transtemporal sinus wall reconstruction has a high rate of success in appropriately selected patients. Patients with isolated sinus wall dehiscence without diverticulum, TSS, or empty sella are less likely to respond to transtemporal sinus wall reconstruction. These data imply a multifactorial cause of PT in at least some patients with SSWA.

LEVEL OF EVIDENCE

4 Laryngoscope, 128:S1-S13, 2018.

CTA/V detection of bilateral sigmoid sinus dehiscence and suspected idiopathic intracranial hypertension in unilateral pulsatile tinnitus

PURPOSE

This aimed to evaluate the prevalence and extent of bilateral sigmoid sinus dehiscence (SSD) and to explore the presence of idiopathic intracranial hypertension (IIH) in patients with unilateral pulsatile tinnitus (PT) with CTA/V.

METHODS

Sixty PT patients (52 females; 40.4 ± 11.6 years [20-72]) who underwent CTA/V and 30 non-PT patients (27 females; 38.4 ± 14.7 years [12-62]) were enrolled in this study. The primary outcome measure was the radiographic presence of SSD. The index of transverse sinus stenosis (ITSS) was obtained by multiplying the stenosis scale values for each transverse sinus, and once was ≥ 4, the presence of IIH was suspected.

RESULTS

The prevalence and extent of SSD on symptomatic side (78%; maximum transverse diameter, MTD 0.49 ± 0.23; maximum vertical diameter, MVD 0.50 ± 0.26 cm) were significantly higher and larger than those on asymptomatic side (50%, P < 0.001; MTD 0.35 ± 0.18, P = 0.006; MVD 0.30 ± 0.15 cm, P < 0.001) in the study group and those (20%, P < 0.001; MTD 0.36 ± 0.18, P = 0.073; MVD 0.30 ± 0.22 cm, P < 0.048) in the control group. The presence of SSD showed significant correlation with both PT (logistic regression analysis, OR 4.167 [1.450-11.97]; P = 0.008) and suspected IIH (OR 16.25 [1.893-139.5]; P = 0.011).

CONCLUSION

In PT patients, SSD has a significant correlation with PT and a potential correlation with IIH.

Radiologic features of vascular pulsatile tinnitus - suggestion of optimal diagnostic image workup modalities

OBJECTIVES

The aim of this study was to determine the optimal diagnostic workup modalities for vascular pulsatile tinnitus through analysis of clinical and radiologic findings.

MATERIALS AND METHODS

A total of 49 patients diagnosed with vascular pulsatile tinnitus along with their medical records and radiologic findings were thoroughly reviewed.

RESULTS

Of these patients, 84% had venous lesions. The jugular bulb variants (67%) were the most common venous lesions followed by sigmoid sinus variants (12%). About 88% (43/49) of these lesions were detected with computed tomography of the temporal bone (TBCT) alone and the lesions were either venous or intratemporal artery in origin. Simple manual neck compression test was 93% sensitive in predicting venous lesions. A high suspicion for venous lesion coupled with manual neck compression test and selection of the optimal imaging technique are useful for the proper evaluation of vascular pulsatile tinnitus at the initial visit.

CONCLUSION

Our stepwise strategy may increase the cost-effectiveness of the chosen imaging workup by reducing redundancy of multiple and simultaneous radiologic tests in patients with vascular pulsatile tinnitus.

Aberrant sylvian vein: A newly described cause of pulsatile tinnitus

We herein report a newly described cause of venous pulsatile tinnitus: protrusion of an aberrant sylvian vein into the tympanum. A 60-year-old woman presented with a 4-month history of objective persistent pulsatile tinnitus in the right ear with no other complaints. The pulsatile tinnitus diminished with rotation of the head to the right side or by compression of the right cervical vascular structures. The frequency and intensity of the tinnitus were 125 Hz and 20 dB HL, respectively. Audiometry and otoscopic examination findings were normal. Radiologic examination showed that the right sylvian vein protruded into the tympanum through the dehiscent anterior cortical plate of the tympanum.

Sigmoid Sinus Wall Reconstruction for Pulsatile Tinnitus Caused by Sigmoid Sinus Wall Dehiscence: A Single-Center Experience

OBJECTIVE

To evaluate clinical characteristics and present surgical outcomes of PT caused by sigmoid sinus wall dehiscence (SSWD).

METHODS

This study retrospectively reviewed 34 patients with PT who were diagnosed with SSWD in our institution between December 2008 and July 2013. Among them, 27 patients underwent sigmoid sinus wall reconstruction (surgery group) and 7 patients refused surgery (non-surgery group). Preoperative data were obtained from the patients' medical records. All patients were followed up regularly for at least 25 months. Preoperative and postoperative computed tomography angiography (CTA) images were compared. Student's t-tests were used to compare age, body mass index (BMI) and preoperative Tinnitus Handicap Inventory (THI) scores between the surgery and the non-surgery groups and to compare pre- and follow-up THI scores.

RESULTS

There was no significant difference in age, body mass index, or preoperative THI scores between groups. Following surgery, 14 patients had complete resolution, 5 had partial resolution, 7 experienced no change and PT was aggravated in 1 patient. The difference between preoperative and postoperative THI scores was significant. No severe complications were found postoperatively. Comparison of the preoperative and postoperative CTA images revealed that remnant unrepaired dehiscences were the cause of unsatisfactory outcomes following surgery. In the non-surgery group, PT remained largely unchanged.

CONCLUSIONS

Sigmoid sinus wall reconstruction is an effective and safe treatment for PT caused by SSWD. It is imperative that all regions of the dehiscence are sufficiently exposed and resurfaced during surgery.

Association between the extent of sigmoid sinus dehiscence and an occurrence of pulsatile tinnitus: a retrospective imaging study

AIM

To assess the extent of sigmoid sinus dehiscence (SSD) on high-resolution computed tomography venography (HRCTV) or high-resolution computed tomography (HRCT) images in pulsatile tinnitus (PT) and non-PT groups to determine whether there is an association between the extent of SSD and occurrence of PT.

MATERIALS AND METHODS

Twenty-eight SSD patients with ipsilateral PT and 28 age- and gender-matched SSD patients without PT who underwent HRCTV or HRCT were enrolled in this study and categorised into two groups: "PT group" and "non-PT group". The extent of SSD in each group was calculated and compared.

RESULTS

The largest transverse diameter and largest vertical diameter of SSD in the PT group were 6.21±1.7 and 6.15±2.19 mm, respectively. The largest transverse diameter and largest vertical diameter of SSD in the non-PT group were 3.06±1.38 and 2.51±1.03 mm, respectively. The extent of SSD was statistically different between the two groups (p<0.001; p<0.001).

CONCLUSIONS

As a cause of PT, SSD can also occur in individuals without PT symptoms. Preliminary findings suggest that there may be a potential correlation between the extent of SSD and an occurrence of PT.

CT characteristics of dehiscent sigmoid plates presenting as pulsatile tinnitus: a study of 23 patients

BACKGROUND

Although some features of dehiscent sigmoid plates as a cause of pulsatile tinnitus (PT) have been reported, detailed imaging findings have not been evaluated.

PURPOSE

To retrospectively evaluate the computed tomography (CT) features of dehiscent sigmoid plates associated with PT.

MATERIAL AND METHODS

The CT images of 23 PT patients were assessed to evaluate the features of the dehiscent sigmoid plates, lateral sinuses, and temporal bone pneumatization.

RESULTS

A total of 31 defects were found on the PT side. Twenty-five defects involved the superior curve or the descending segment, four involved above both sites, and only two involved the inferior curve. Twenty-six defects involved the anterior border or the anterolateral border, and only five involved the lateral border of the sigmoid sinus. The dehiscent sigmoid plate was on the dominant side in all 18 patients with a unilateral dominant lateral sinus, and on the right side in two patients and on the left side in three patients with co-dominant lateral sinuses. Fourteen patients had hyperpneumatization and nine had good pneumatization of temporal bone. Fifteen of the 17 patients with resolution of PT after surgery had a single defect. Four of the six patients with persistence of PT after surgery had more than one defect.

CONCLUSION

Sigmoid plate dehiscence often involves the anterior or anterolateral border of the superior curve or the descending segment of the sigmoid sinus on the side of the dominant lateral sinus, which often coexists with extensive pneumatization of the temporal bone.

Superior semicircular canal dehiscence in relation to the superior petrosal sinus: a potential cause of pulsatile tinnitus

AIM

To examine the association between superior semicircular canal dehiscence (SSCD) and pulsatile tinnitus (PT).

MATERIALS AND METHODS

Two SSCD groups included 408 unilateral persistent PT patients, and 511 controls undergoing head and neck dual-phase contrast-enhanced computed tomography (DP-CECT) for reasons other than PT. The prevalence of type I (no the superior petrosal sinus running through the dehiscence) and type II (superior semicircular canal dehiscence in relation to the superior petrosal sinus) SSCD was analysed using chi-square test.

RESULTS

SSCD was identified in 5.1% (21/408) of PT ears, significantly different from 2% (8/408) of non-PT ears and 0.7% (7/1022) of controls. There was no significant difference in SSCD prevalence between non-PT ears in the PT group and controls. In the PT group, 15/21 ears were type II SSCD; 6/21 ears were type I. Fifteen combined non-PT and control ears with SSCD included two type II and 13 type I SSCD. The prevalence of type II SSCD in PT ears was significantly higher than that of non-PT ears in both groups, and the prevalence of type I SSCD in PT ears was similar to that of non-PT ears in both groups.

CONCLUSION

Compared with type I SSCD, there may be a causal relationship between type II SSCD and PT.

Sinus Wall Resurfacing for Patients With Temporal Bone Venous Sinus Diverticulum and Ipsilateral Pulsatile Tinnitus

BACKGROUND:

Pulsatile tinnitus (PT) caused by venous sinus diverticulum is a relatively common, potentially incapacitating condition. Although treatment via an external approach or endovascular coiling has been reported, much remains unknown about the possible pathophysiological mechanisms and appropriate management of PT.

OBJECTIVE:

To review our case series of PT resulting from either sigmoid sinus diverticulum (SSD) or middle cranial fossa venous sinus diverticulum (MFD-VS) and to discuss the possible pathophysiological mechanisms and desirable treatment options.

METHODS:

Four PT patients with either SSD or MFD-VS were treated with transmastoid resurfacing. In 1 case, a revision operation was performed as a result of recurrence of PT 4.5 years after the initial operation. The medical records and temporal bone imaging findings were retrospectively reviewed.

RESULTS:

PT was resolved in all cases immediately after transmastoid resurfacing, but 1 patient in whom bone wax was used for initial resurfacing experienced PT 4.5 years later. The PT was successfully managed with revision resurfacing with autologous bone chips/bone cement. In the other cases, the resolution of PT lasted throughout a median follow-up of 5.75 years. Notably, 2 of 4 cases had preoperative low-frequency hearing loss (LFHL) and experienced immediate postoperative improvement in LFHL.

CONCLUSION:

PT resulting from either SSD or MFD-VS can be treated successfully with transmastoid resurfacing of the venous wall. Preoperative ipsilesional LFHL and the improvement of hearing threshold after surgical intervention may be preoperative and postoperative surrogate objective signatures of PT. To ensure the resolution of symptoms, secure reconstruction with firm materials and long-term follow-up are mandatory.

Association between idiopathic intracranial hypertension and sigmoid sinus dehiscence/diverticulum with pulsatile tinnitus: a retrospective imaging study

INTRODUCTION

The mechanism of occurrence of sigmoid sinus dehiscence/diverticulum (SSDD) in pulsatile tinnitus (PT) patients remains under debate. Its association with idiopathic intracranial hypertension (IIH) lacks evidence, which is important for therapeutic planning and improving the clinical outcome. This study aimed to evaluate the association between SSDD and IIH by comparing the prevalence of several established imaging features of IIH between PT patients with SSDD and healthy volunteers.

METHODS

Thirty-three unilateral PT patients with SSDD identified on CT images and 33 age- and sex-matched healthy volunteers underwent T1-weighted volumetric magnetic resonance imaging (MRI). The optic nerve, pituitary gland, transverse sinus, and ventricles were assessed. The prevalence of established IIH imaging features was compared between the two groups. Furthermore, the PT patients were divided into two subgroups: PT patients with dehiscence only and PT patients with diverticulum. The same statistical analysis was performed on each pathophysiologic entity respectively.

RESULTS

The PT patients with SSDD showed a significantly higher prevalence of empty sella (P < 0.001), flattened posterior sclera (P = 0.001), vertical tortuosity of the optic nerve (P = 0.001), protrusion of the optic nerve (P = 0.006), transverse sinus stenosis (P = 0.011), and distension of the optic nerve sheath (P = 0.000). There were no significant differences between the PT and control groups in the maximum widths of the third and fourth ventricles and the lateral ventricle size. In contrast to controls, the imaging findings persisted in both of pathophysiologic entities, except for transverse sinus stenosis.

CONCLUSIONS

Several IIH imaging features occur more frequently in PT patients with SSDD than in healthy individuals, which suggests a potential correlation between SSDD with PT and IIH.

Sigmoid plate dehiscence: congenital or acquired condition?

BACKGROUND AND PURPOSE

The imaging features of sigmoid plate dehiscence-induced pulsatile tinnitus have been presented. The origin of the sigmoid plate dehiscence, however, remains unclear. Our aim was to assess the prevalence and extent of sigmoid plate dehiscence on computed tomography (CT) images in multiple age groups to determine whether this condition is more likely to be congenital or acquired.

MATERIALS AND METHODS

We retrospectively reviewed contrast-enhanced CT images of sigmoid plates of temporal bones in 504 patients. Each temporal bone was characterized as normal or dehiscent. Patients were then subcategorized into four age groups, and the prevalence and extent of dehiscent sigmoid plates in each group were calculated and compared.

RESULTS

Overall, 80 patients had sigmoid plate dehiscence, nine of whom had it bilaterally. In successively older age groups, the prevalences of sigmoid plate dehiscence were 18.9%, 20.1%, 14.5%, and 12.7%, respectively. Respective average anteroposterior bony defect diameters were 3.7±1.7, 3.0±1.3, 3.1±1.5, and 3.0±1.1 mm. Respective average vertical bony defect diameters were 3.6±2.3, 2.6±1.2, 3.2±1.5, and 3.0±1.7 mm. The prevalence and extent of sigmoid plate dehiscence were not statistically different among the four age groups.

CONCLUSIONS

The similar radiologic prevalence and extent of dehiscent sigmoid plates among the age groups suggest that the dehiscence is more commonly a congenital than an acquired condition.

Surgical treatment of pulsatile tinnitus caused by the sigmoid sinus diverticulum: a preliminary study

The sigmoid sinus diverticulum (SSD) is an increasingly recognized cause of pulsatile tinnitus (PT). Surgical reconstruction of the sigmoid sinus wall has been found to be highly effective for SSD; however, surgical techniques still need to be refined to reduce the incidence of serious postoperative complications. Moreover, scrutinizing more cases of SSD is desirable for establishing the diagnostic criteria and standardizing the surgical technique. This study was retrospectively undertaken in 28 patients who were diagnosed with SSD upon computed tomography angiography (CTA) and digital subtraction angiography findings at Beijing Tongren Hospital in China. A majority of patients (20/28) presented with SSD and accompanying sigmoid sinus wall dehiscence (SSWD). Twenty-five patients opted to undergo sigmoid sinus wall reconstruction, and 3 patients refused surgery. Following surgery, 17 patients experienced complete resolution of PT, 3 patients experienced partial resolution, and 5 patients experienced no change in PT. No serious complications were found postoperatively. A comparative analysis of the preoperative and postoperative CTA findings suggested that completely resolving SSD and the accompanying SSWD resulted in the elimination of PT. In conclusion, SSD is generally accompanied by SSWD. Sigmoid sinus wall reconstruction is a safe and effective approach for the treatment of SSD. During surgery, completely resolving both SSD and SSWD is advisable, and maintaining the normal diameter of the sigmoid sinus is imperative.

Incidence of vascular anomalies and variants associated with unilateral venous pulsatile tinnitus in 242 patients based on dual-phase contrast-enhanced computed tomography

BACKGROUND

A comprehensive assessment of various vascular anomalies and variants associated with venous pulsatile tinnitus (PT) by radiography is essential for therapeutic planning and improving the clinical outcome. This study evaluated the incidence of various vascular anomalies and variants on the PT side and determined whether these lesions occurred as multiple or single entities.

METHODS

The dual-phase contrast-enhanced computed tomography images of 242 patients with unilateral venous PT were retrospectively reviewed. The vascular anomalies and variants on the symptomatic and asymptomatic sides were analyzed, and the incidences of anomalies or variants on each side were compared. The number of anomalies and variants on the symptomatic side in each patient was calculated.

RESULTS

(1) A total 170 patients (170/242) had more than one anomaly or variant on the symptomatic side, and 58 patients (58/242) had a single lesion on tomography. (2) There was a statistically significant difference in the incidence of dehiscent sigmoid plate (P = 0.000), lateral sinus stenosis (P = 0.014), high jugular bulb (P = 0.000), sigmoid sinus diverticulum (P = 0.000), jugular bulb diverticulum (P = 0.000), dehiscent jugular bulb (P = 0.000), and a large emissary vein (P = 0.006) between the symptomatic and asymptomatic sides. (3) Dehiscent sigmoid plate (86.4%) was the most frequent lesion on the symptomatic side, followed by lateral sinus stenosis (55.8%), high jugular bulb (47.1%), sigmoid sinus diverticulum (34.3%), jugular bulb diverticulum (13.6%), dehiscent jugular bulb (13.6%), large emissary vein (4.1%), sinus thrombosis (1.2%), and petrosquamosal sinus (0.8%).

CONCLUSIONS

Various vascular anomalies and variants occur more frequently on the venous PT side. Preliminary findings suggest that venous PT patients may have multiple vascular anomalies or variants on the symptomatic side.

Temporal Bone Pneumatization and Pulsatile Tinnitus Caused by Sigmoid Sinus Diverticulum and/or Dehiscence

BACKGROUND

Although air cells within temporal bone may play an important role in the transmission of pulsatile tinnitus (PT) noise, it has not been studied systematically.

PURPOSE

To evaluate the difference in temporal bone pneumatization between PT patients with sigmoid sinus diverticulum and/or dehiscence (SSDD) and healthy people.

MATERIAL AND METHODS

A total of 199 unilateral persistent PT patients with SSDD and 302 control subjects underwent dual-phase contrast-enhanced CT (DP-CECT), to assess the grade of temporal bone pneumatization in each ear.

RESULTS

In the bilateral temporal bone of 302 controls, 16 ears were grade I, 53 were grade II, 141 were grade III, and 394 were grade IV. Among the affected ears of 199 PT cases, 1 ear was grade I, 18 were grade II, 53 were grade III, and 127 were grade IV. There was no significant difference in the pneumatization grade between the affected PT ear and either ear in the healthy subjects (p > 0.05).

CONCLUSION

Although air cells within the temporal bone are an important factor in the occurrence of PT, its severity does not differ significantly from the pneumatization of healthy people.

CT arteriography and venography in the evaluation of Pulsatile tinnitus with normal otoscopic examination

OBJECTIVES/HYPOTHESIS

Our retrospective study aims to assess the ability of computed tomography arteriography and venography (CT A/V) to detect various findings that suggest a potential cause of pulsatile tinnitus and to examine the association between these findings and the side of pulsatile tinnitus.

STUDY DESIGN

A retrospective review of CT arteriography and venography of 32 patients with established pulsatile tinnitus and normal otoscopic examination was performed. The scans were performed using a 64-slice multidetector scanner and were reviewed to look for findings that are known to cause pulsatile tinnitus.

RESULTS

One or more findings that are known to cause pulsatile tinnitus were detected on the symptomatic side in 30 patients; on the asymptomatic side in 3 patients, one patient with bilateral pulsatile tinnitus showed a potential cause of symptoms only on one side, and in one patient no potential cause could be identified. There is a significant association seen between the side of pulsatile tinnitus and various potential causes of pulsatile tinnitus detected (P < 0.001), between the side of pulsatile tinnitus and various potential venous cause detected (P < 0.001), and between the side of pulsatile tinnitus and the side of dominant venous system (P = 0.02).

CONCLUSION

CT arteriography and venography is a useful tool in detecting many described potential causes of pulsatile tinnitus. Significant association is demonstrated between the side of pulsatile tinnitus and the potential causes of pulsatile tinnitus detected by CT arteriography and venography when the otoscopic examination is normal.