The incidence of symptoms consistent with cerebellopontine angle lesions in a general ENT out-patient clinic

Finding more than what you are looking for: a retrospective study of incidental findings in magnetic resonance imaging (MRI) scans performed for patients suspicious of vestibular schwannoma

Background

Nearly 20% of the patients presenting to ENT department with audiovestibular symptoms are considered potential candidates for vestibular schwannoma screening. MRI scan done on these patients can also detect a large number of incidental findings. We did a retrospective descriptive study of incidental findings identified on MRI scans done on patients presenting to the ENT department in a county hospital in United Kingdom from April 2020 to April 2021. All MRI reports were scrutinised and various incidental findings tabulated. The further management of patients with these findings were also analysed.

Results

A total of 159 MRIs were reviewed. The most common incidental finding was small vessel disease followed by old infarcts. Fifteen patients were found to have significant incidental findings. The detection rate of vestibular schwannoma was 3.1%.

Conclusion

With the increased use of imaging technology, the incidence of incidental findings has risen. Understanding the significance of these findings is important so that clinicians can counsel their patients and make appropriate management plans. Categorising the incidental findings into groups based on their level of significance may help in making these clinical decisions.

Imaging of the Vestibular Schwannoma: Diagnosis, Monitoring, and Treatment Planning

Appropriate imaging strategies for the detection, treatment planning, and posttreatment monitoring of vestibular schwannomas will be discussed. The typical and variant imaging appearances of vestibular schwannomas, as well as the imaging features that should prompt consideration of differential diagnoses, will be illustrated. Understanding the natural history of vestibular schwannomas, optimal measurement and definition of tumour growth helps the radiologist evaluate for the failure of conservative management and requirement for surgery or radiotherapy. In order to determine the success of conservative management, the radiologist is required to understand the natural history of vestibular schwannomas and how tumour growth is defined. Finally, the imaging features which help guide appropriate treatment with surgery or radiotherapy will be highlighted, and the expected posttreatment imaging changes will be described.

Predictors of Postoperative Complications in Vestibular Schwannoma Surgery-A Population-Based Study

OBJECTIVE

To investigate preoperative patient demographics and comorbidities in relation with postsurgical complications following vestibular schwannoma surgery.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING

All hospitals in the Canadian province of Ontario.

PATIENTS

This study includes 1,456 patients who underwent vestibular schwannoma surgery from April 1, 2002 to March 31, 2018 in Ontario, Canada.

INTERVENTION/OUTCOME MEASURES

For all surgical patients, the demographic data, preoperative comorbidities, and postoperative complications were evaluated. Postoperative complications were examined immediately following surgery in the hospital as well as 1 year following the hospital discharge.

RESULTS

The most common comorbidities in this cohort were hypertension (30.22%), diabetes (9.48%), asthma (13.53%), and chronic obstructive pulmonary disease (6.73%). Diabetes was the most impactful comorbidity and was associated with higher risk of myocardial infarction (RR = 4.58, p < 0.01), pneumonia (RR = 1.80, p = 0.02), dysphagia (RR = 1.58, p < 0.01), and meningitis (RR = 3.62, p < 0.01). Analysis of surgical approaches revealed that the translabyrinthine approach, compared with the open craniotomy approach, was negatively associated with postoperative complications including pneumonia (RR = 0.43, p < 0.01), urinary tract infection (RR = 0.55, p = 0.01), dysphagia (RR = 0.66, p < 0.01), and readmission (RR = 0.45, p < 0.01).

CONCLUSION

This study examines patient demographics, preoperative comorbidities, and postoperative complications in patients who have undergone vestibular schwannoma surgery. The results highlight associations between patient characteristics and postoperative outcomes that can aid in preoperative decision-making and counselling.

The use of magnetic resonance imaging in the investigation of patients with unilateral non-pulsatile tinnitus without asymmetrical hearing loss

BACKGROUND

Tinnitus is a common condition presenting to the ENT out-patient clinic. Vestibular schwannomas are benign cerebellopontine angle tumours that usually present with unilateral sensorineural hearing loss. Magnetic resonance imaging of the internal auditory meatus is the definitive investigation in their detection. The current recommendation is for unilateral tinnitus patients to undergo magnetic resonance imaging of the internal auditory meatus to exclude vestibular schwannoma.

OBJECTIVE

To evaluate magnetic resonance imaging in the investigation of patients with unilateral non-pulsatile tinnitus without asymmetrical hearing loss.

METHOD

A retrospective case series was conducted of all patients who underwent magnetic resonance imaging of the internal auditory meatus to investigate unilateral non-pulsatile tinnitus without asymmetrical hearing loss, from 1 January 2014 to 1 January 2019.

RESULTS

Of 2066 scans, 566 (27 per cent) were performed to investigate patients (335 female, 231 male) with unilateral non-pulsatile tinnitus without asymmetrical hearing loss. Three vestibular schwannomas were detected on imaging, and 134 incidental findings were discovered.

CONCLUSION

The detection rate of vestibular schwannoma in this group was just 0.3 per cent. This paper questions the utility of magnetic resonance imaging evaluation in these patients.

Vestibular Schwannoma: What We Know and Where We are Heading

Vestibular schwannoma (VS) is a Schwann cell-derived tumour arising from the vestibulocochlear nerve. Although benign, it represents a threat to intracranial structures due to mass effect and carries a small risk of malignant transformation. VS therefore represents an important healthcare burden. We review the literature regarding pathogenesis, risk factors, and diagnosis of VS. The current and future potential management strategies are also discussed. A narrative review of all relevant papers known to the authors was conducted. The majority of VS remain clinically stable and do not require interventional procedures. Nevertheless, various surgical techniques exist for removing VS, the most common of which are translabyrinthine and retrosigmoid approaches. Due to surgical risks such as hearing loss, facial nerve dysfunction, post-operative headache, and cerebrospinal fluid leakage, a "watch and rescan" approach is adopted for most patients. Radiotherapy is a useful alternative and has been shown to have a similar response for growth restriction. Due to the heterogeneous nature of VS, there is a lack of consensus regarding management of tumours that are too large for conservative management but too small to indicate surgery. Emerging biologic therapies, such as Bevacizumab, Everolimus, and Lapatinib, as well as anti-inflammatories like aspirin are promising potential treatments; however, long-term evidence of their efficacy is required. The knowledge base regarding VS continues to improve. With increased understanding of the pathogenesis of these tumors, we believe future work should focus on pharmacologic intervention. Biologic therapies aimed toward improved patient outcomes are particularly promising.

Incidence of vestibular schwannoma and incidental findings on the magnetic resonance imaging and computed tomography scans of patients from a direct referral audiology clinic

OBJECTIVE

To identify the incidence of vestibular schwannoma amongst patients referred from a direct referral audiology clinic, and also the number of incidental findings, as seen on magnetic resonance imaging or computed tomography scans.

METHOD

Prospective data collection for patients referred from a direct referral audiology clinic due to audiological evidence of asymmetrical hearing loss. The audiograms, magnetic resonance imaging and computed tomography scans of patients with diagnosed vestibular schwannoma were subsequently reviewed.

RESULTS

A total of 4100 patients were seen during the study period, with 396 scans performed. Six (1.5 per cent) patients had vestibular schwannoma, while 12 (3 per cent) had significant incidental findings.

CONCLUSION

Patients referred from the direct referral audiology clinic had a low incidence of vestibular schwannoma detection. Their detection rate for significant incidental findings was similar to previous reports. If the current protocol had not been in place, over 300 patients would have been needlessly added to the ENT clinic list. Thus, general practitioner referral to direct referral audiology clinics provides a cost-effective way of managing asymmetrical sensorineural hearing loss in older patients. The number of such clinics could be expanded.

Should all patients referred for magnetic resonance imaging scans of their internal auditory meatus be followed up in ENT clinics?

Magnetic resonance imaging (MRI) is recognised as the "Gold Standard" investigation for symptoms pertaining to the inner ear and detection of retro-cochlear pathology. There is still no accurate clinical predictor for cerebellopontine angle lesions and increasingly more normal scans are being performed. With constantly increasing demands on ENT outpatient clinics, our aim was to investigate whether all patients referred for MRI of their internal auditory meatus (IAM) require follow-up in ENT clinics. A retrospective study was carried out in a tertiary referral centre referring patients for MRI IAM from ENT clinics and neurotology clinics on 153 patients referred for MRI IAM performed over a 4-month period. The MRI reports and the case notes of the patients were reviewed. MRI results and patient symptoms with patient follow-up schedule and follow-up situation for at least 6 months post-scan were compared. There were two patient groups, those referred from main outpatients (81) and those referred by the audiological physicians (72). Of the total number of scans, 101 were reported as normal, 45 had incidental findings, and 7 showed pathology of the cerebellopontine angle. The presenting complaints of the patients, the scan results and the follow-up since were compared. Six months later 63% of those referred from outpatients were no longer being followed up in clinic. We suggest that 56.8% of patients referred for MRI IAM do not require ENT follow-up. Their symptoms and concerns could be dealt with at the first consultation where onward referral could be made if necessary. Once checked by the requesting clinician, uncomplicated scan results could be sent to the patients and general practitioners by post or email. This would reduce the burden on general otolaryngology outpatient clinics and improve resource utilisation.

Change in hearing during ‘wait and scan’ management of patients with vestibular schwannoma

Aim:

To evaluate hearing changes during ‘wait and scan’ management of patients with vestibular schwannoma.

Subjects:

Over a 10-year period, 636 patients have prospectively been allocated to ‘wait and scan’ management, with annual magnetic resonance scanning and audiological examination.

Results:

At the time of diagnosis, 334 patients (53 per cent) had good hearing and speech discrimination of better than 70 per cent; at the end of the 10-year observation period, this latter percentage was 31 per cent. In 17 per cent of the patients, speech discrimination at diagnosis was 100 per cent; of these, 88 per cent still had good hearing at the end of the observation period. However, in patients with even a small initial speech discrimination loss, only 55 per cent maintained good hearing at the end of the observation period.

Conclusion:

After comparing the hearing results of hearing preservation surgery and of radiation therapy with those of ‘wait and scan’ management, it appears that, in vestibular schwannoma patients with a small tumour and normal speech discrimination, the main indication for active treatment should be established tumour growth.

Screening patients with sensorineural hearing loss for vestibular schwannoma using a Bayesian classifier

OBJECTIVES

Selecting patients with asymmetrical sensorineural hearing loss for further investigation continues to pose clinical and medicolegal challenges, given the disparity between the number of symptomatic patients, and the low incidence of vestibular schwannoma as the underlying cause. We developed and validated a diagnostic model using a generalisation of neural networks, for detecting vestibular schwannomas from clinical and audiological data, and compared its performance with six previously published clinical and audiological decision-support screening protocols.

DESIGN

Probabilistic complex data classification using a neural network generalization.

SETTINGS

Tertiary referral lateral skull base and a computational neuroscience unit.

PARTICIPANTS

Clinical and audiometric details of 129 patients with, and as many age and sex-matched patients without vestibular schwannomas, as determined with magnetic resonance imaging.

MAIN OUTCOME MEASURES

The ability to diagnose a patient as having or not having vestibular schwannoma.

RESULTS

A Gaussian Process Ordinal Regression Classifier was trained and cross-validated to classify cases as 'with' or 'without' vestibular schwannoma, and its diagnostic performance was assessed using receiver operator characteristic plots. It proved possible to pre-select sensitivity and specificity, with an area under the curve of 0.8025. At 95% sensitivity, the trained system had a specificity of 56%, 30% better than audiological protocols with closest sensitivities. The sensitivities of previously-published audiological protocols ranged between 82-97%, and their specificities ranged between 15-61%.

DISCUSSION

The Gaussian Process ORdinal Regression Classifier increased the flexibility and specificity of the screening process for vestibular schwannoma when applied to a sample of matched patients with and without this condition. If applied prospectively, it could reduce the number of 'normal' magnetic resonance (MR) scans by as much as 30% without reducing detection sensitivity. Performance can be further improed through incorporating additional data domains. Current findings need to be reproduced using a larger dataset.

The compliance, true positive and false negative rates of the Charing Cross protocol for magnetic resonance imaging screening for cerebellopontine angle lesions

OBJECTIVES

To assess the effectiveness and determine the compliance to a local protocol for requesting magnetic resonance imaging scans to screen for the presence of cerebellopontine angle lesions.

METHODS

A combined retrospective study of all patients who had magnetic resonance imaging scans requested six months prior to and one year following introduction of the protocol and assessment of the true positive and false negative rate of the protocol by assessment of its sensitivity in cases referred from outside the department.

RESULTS

Comparison of the number of scans in each period showed a reduction in annualised rate of 142 to 46. The incidence of positive scans was the same in both periods, increasing the true positive rate from 1.4 to 4.3 per cent. The false negative rate was 1.1 per cent.

CONCLUSIONS

The Charing Cross protocol has a good compliance rate within the department, has reduced the cost of screening for cerebellopontine angle lesions and has an acceptable true positive and false negative rate.

[Magnetic resonance: first choice test in the screening of internal auditory canal and cerebellopontine angle tumors]

Although internal auditory canal (IAC) and cerebellopontine angle (CPA) tumors are rare, their clinical suspicion is quite common in the otolaryngology office. MRI is the imaging modality of choice in diagnosing these tumors. Perceived high costs may prevent clinicians from using it as a screening tool. A protocol designed to improve cost-effectiveness in such diagnosis results in a more rationale clinical practice. Our aim was to evaluate the usefulness of MRI as screening tool in diagnosis of IAC and CPA tumors in our population. Between March 1998 and March 2000, a prospective series of 200 cases had a MRI screening requested. MRI were performed following Fast Spin Echo technique, providing T2-weighted images. Gadolinium enhanced MRI was reserved for selected cases. We report on 190 MRI done. We found 7 neuromas (3.5%), one CPA metastasis, one epidermoid cyst and 9 IAC vascular anomalies. Only 138 cases (69%) had normal MRI images. When used following a designed protocol, MRI is our procedure of choice while screening IAC and CPA tumors because it is a cost-effective tool.