Audit of the appropriateness of MRI IAM referrals in patients presenting with tinnitus and the subsequent imaging investigations carried out

Audit of the appropriateness of MRI IAM referrals in patients presenting with tinnitus and the subsequent imaging investigations carried out.

The increased availability and easy accessibility of MRI have resulted in a rise in imaging requests for patients experiencing tinnitus (1). However, clinical data often fails to specify the type of tinnitus (pulsatile or non-pulsatile), leading to the referral of all cases for Magnetic Resonance Imaging (MRI) of the internal auditory meati (IAM) as a screening test for vestibular schwannoma (1). Pulsatile tinnitus is typically caused by vascular abnormalities or middle ear tumours, for which contrast-enhanced CT scans were traditionally preferred (2).  On the other hand, non-pulsatile tinnitus is more likely to be caused by functional injuries from environmental noise exposure or iatrogenic through toxicity from certain medications (2, 3). It rarely indicates vestibular schwannoma, which is best diagnosed using MRI according to the RCR iRefer guidelines (4).

The updated 2020 NICE guidelines have made recommendations on changing criteria for when MRI of the IAM is indicated and considered while taking into account clinical context (5).

MRI of the IAM is indicated in those with non-pulsatile tinnitus who have associated neurological, otological, or head and neck signs and symptoms. However, MRI of IAM remains indicated in those with unilateral tinnitus even without associated symptoms as this is considered a red flag symptom of acoustic or intracranial pathology (5).

In regards to pulsatile tinnitus, NICE advises for synchronous pulsatile tinnitus to consider magnetic resonance angiogram or MRI of the head, neck, temporal bone and IAM if clinical and audiological examinations are normal. In cases where patients cannot tolerate MR or is contraindicated, to utilise contrast-enhanced CT. Additionally, contrast-enhanced CT of temporal bone is indicated in those with suspected osseous or middle ear abnormalities. NICE advises to utilise MRI in those patient cohort if further investigation and visualisation of soft tissues is necessary (5).

As for asynchronous pulsatile tinnitus, to consider MRI of the head or contrast-enhanced CT in those where MR is contraindicated (5).

The standard:

The standard: Imaging requests should clearly state: 1. Type of tinnitus (pulsatile or non-pulsatile) 2. Side affected (unilateral/bilateral) 3. Associated neurological, audiological, otological or head and neck signs and symptoms. 4. Type of investigation carried out.

Target:

Target 100% compliance

Indicators:

1. Percentage of imaging requests for tinnitus which do not specify its type (pulsatile/non-pulsatile)

2. Percentage of imaging requests for tinnitus which do not specify associated symptoms or where associated symptoms are included, they are normal.

Data items to be collected:

 1. Patients who have been referred for MRI IAM with “pulsatile tinnitus”, “non-pulsatile tinnitus” or “tinnitus” in clinical information.

2. Otoscopy findings on examination

3. Poor hearing and laterality on audiology assessment

4. Self-reported poor hearing and laterality

5. Focal neurological examination findings

Suggested number:

100 patients

Suggestions for change if target not met:

1. Discuss audit results with local radiologists and the referring clinicians.

2. Identify the cases in which the NICE guidelines were not followed and the outcome of their imaging.

3. Consider further education for the referrers of the new guidelines and/or modify MRI vetting process to decline requests without sufficient clinical information.

4. Use of mandatory prompts for electronic imaging request service.

5. Consider creating a bespoke pathway in clinical decision support (such as RCR iRefer CDS Authoring Suite) in organisations where this is available.

1. Vandervelde C, Connor SE. Diagnostic yield of MRI for audiovestibular dysfunction using contemporary referral criteria: correlation with presenting symptoms and impact on clinical management. Clin Radiol. 2009;64(2):156-63.

2. Vattoth S, Shah R, Curé JK. A compartment-based approach for the imaging evaluation of tinnitus. AJNR Am J Neuroradiol. 2010;31(2):211-8.

3. Hoang JK LL. Evaluation of Tinnitus and Hearing Loss in the Adult. In: Hodler J K-HR, von Schulthess GK, editor. Diseases of the Brain, Head and Neck, Spine 2020-2023: Diagnostic Imaging: Springer; 2020.

4. iRefer. Sensorineural hearing loss guidelines (Available from irefer.org,uk)

5. NICE. Tinnitus: assessment and management. 2020 (https://www.nice.org.uk/guidance/ng155)

1. Vandervelde C, Connor SE. Diagnostic yield of MRI for audiovestibular dysfunction using contemporary referral criteria: correlation with presenting symptoms and impact on clinical management. Clin Radiol. 2009;64(2):156-63.

2. Vattoth S, Shah R, Curé JK. A compartment-based approach for the imaging evaluation of tinnitus. AJNR Am J Neuroradiol. 2010;31(2):211-8.

3. Hoang JK LL. Evaluation of Tinnitus and Hearing Loss in the Adult. In: Hodler J K-HR, von Schulthess GK, editor. Diseases of the Brain, Head and Neck, Spine 2020-2023: Diagnostic Imaging: Springer; 2020.

4. iRefer. Sensorineural hearing loss guidelines (Available from irefer.org,uk)

5. NICE. Tinnitus: assessment and management. 2020 (https://www.nice.org.uk/guidance/ng155)

Submitted by:

Dr Antony Antypas

Co-authors:

Dr Antony Antypas