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Evidence review for imaging to investigate the cause of pulsatile tinnitus
Evidence review K
NICE Guideline, No. 155
National Guideline Centre (UK).
1. Imaging to investigate the cause of pulsatile tinnitus
1.1. Review question: What is the most clinical and cost-effective imaging method to investigate the cause of pulsatile tinnitus?
1.2. Introduction
In certain groups of individuals with tinnitus, it is important to image the head and neck to exclude an organic cause for their symptoms. The role of imaging is to detect specific pathology that is treatable. A variety of imaging modalities may be considered depending on the type of tinnitus and/or associated symptoms reported, particularly if the tinnitus is considered to be pulsatile in nature. Imaging modalities include ultrasound, computerised tomography, magnetic resonance imaging and angiography. A thorough history and clinical examination can direct the decision for imaging and the type of imaging.
Pulsatile tinnitus is heard as a regular rhythmical noise. It can occur at the same time as the heart beat (synchronous) or at a different interval (non-synchronous). Synchronous pulsatile tinnitus can be caused by a number of different causes such as irregular blood vessels, high blood pressure, raised intracranial pressure, anaemia and atherosclerosis. Vascular causes may be systemic, for example anaemia, or due to a vascular anomalies or pathology, for example arteriovenous malformation or fistula. Non-vascular pulsatile causes include paragangliomas, intracranial hypertension, osseous pathology and somatic causes. Middle ear pathology such as glomus tumours can also give rise to synchronous tinnitus. Non-synchronous pulsatile tinnitus may be caused by palatal myoclonus. If these conditions are identified they can then be treated, which should also improve the tinnitus.
Whilst it is crucial not to miss significant pathology, it is also important not to over-scan people where significant pathology is unlikely. Not only is this cost unnecessary, it maybe unpleasant and stressful for the person and possibly expose them to an unnecessary dose of ionising radiation or risk of adverse effects from the contrast agent.
1.3. PICO table
For full details see the review protocol in appendix A.
Table 1
PICO characteristics of review question.
1.4. Clinical evidence
1.4.1. Included studies
No relevant randomised controlled trial evidence comparing imaging methods with other imaging methods or with no imaging method were identified. Consequently, non-randomised comparative studies were also assessed. However, no relevant studies were identified for inclusion.
1.4.2. Excluded studies
See the excluded studies list in appendix I.
1.5. Economic evidence
1.5.1. Included studies
No relevant health economic studies were identified.
1.5.2. Excluded studies
No health economic studies that were relevant to this question were excluded due to assessment of limited applicability or methodological limitations.
See also the health economic study selection flow chart in appendix G.
1.6. Unit Costs
Table 2
Unit costs of imaging techniques for non-pulsatile tinnitus.
1.7. Evidence statements
1.7.1. Clinical evidence statements
- No relevant published evidence was identified.
1.7.2. Health economic evidence statements
- No relevant economic evaluations were identified.
1.8. The committee’s discussion of the evidence
1.8.1. Interpreting the evidence
1.8.1.1. The outcomes that matter most
Tinnitus distress, annoyance and tinnitus severity were critical outcomes as they were thought to be common factors for people with tinnitus and impact their quality of life. Quality of life (tinnitus-related) and general quality of life were also critical outcomes due to their impact on the person with tinnitus. Mortality was another critical outcome.
Tinnitus loudness, anxiety, depression, sleep, safety, tolerability and side effects were thought to be important outcomes.
The committee did not prioritise diagnostic accuracy outcomes such as sensitivity and specificity because they felt it was more useful to know about the effect on tinnitus outcomes and cost effectiveness of including these scans in the pathway compared to each other or no scanning.
There was no outcome data for any of the outcomes.
1.8.1.2. The quality of the evidence
Randomised controlled trials (RCTs) and systematic reviews of RCTs were searched for and assessed for eligibility but no relevant RCT evidence was identified which matched the review protocol. Consequently, non-randomised comparative studies were also searched for and assessed for eligibility. No relevant non-randomised comparative studies were identified.
1.8.1.3. Benefits and harms
The committee noted that whilst no evidence was identified, the use of imaging to investigate pulsatile tinnitus is a crucial part of the management pathway and therefore consensus recommendations were made. The committee discussed that there is a risk of anxiety with any scan and healthcare professionals should take this into consideration when offering scans to people with tinnitus. Pulsatile tinnitus may be due to a benign cause, but it can also be due to a vascular malformation or abnormal intracranial pressure that can be potentially significant or life-threatening. Therefore, the committee agreed that imaging should be offered to all age groups with pulsatile tinnitus in order to detect significant and treatable lesions.
Synchronous pulsatile tinnitus
Synchronous pulsatile tinnitus can originate from a number of different causes such as raised intracranial pressure, irregular blood vessels, high blood pressure, anaemia and atherosclerosis. If these conditions are identified they can then be treated which should also improve the tinnitus.
Contrast-enhanced CT scan is more effective at detecting osseous pathology, while MR imaging is more suitable for detecting soft tissue or intracranial pathology. Therefore, the choice of initial imaging method will depend on the clinical suspicion of underlying pathology. For example, middle ear pathology or osseous abnormality such as glomus tumours can give rise to synchronous tinnitus. If this is suspected at examination and audiological assessment, a contrast enhanced CT scan of the temporal bone was considered by the committee to be the best next step to identify the cause.
Magnetic resonance angiography (MRA) can be used to identify or exclude significant and/or treatable disease such as vascular problems. The committee noted that it can also be used to assess the risk of stroke as well as other serious vascular and neurological complications. MRA does not involve ionising radiation, unlike CT scans, and therefore the committee considered this to be the first choice of investigation. Some people may not be able to have or to tolerate an MRA due to metal implants such as pacemakers, or claustrophobia. In these cases, contrast enhanced CT scans of the head, neck, temporal bone and IAM should be considered. CT scans are however associated with a risk from the radiation dose and a risk of sustaining a reaction from the contrast medium. The committee agreed that MRI of the head, neck, temporal bone and IAM with contrast should also be considered. The selection of MRA or MRI is based on experience and equipment available.
There may be instances (e.g. glomus tumour) when both CT and MR imaging can be helpful in improving diagnostic accuracy as they can be complementary in diagnosing and assessing the extent of the medical condition.
Angiography was not recommended by the committee because the committee considered that angiography is associated with a risk of stroke or heart attack, a risk of allergic reaction to the contrast medium and risk from the radiation dose.
Non-synchronous pulsatile tinnitus
Non- synchronous pulsatile tinnitus may be caused by palatal myoclonus. The committee considered that where this is a suspected pathology, an MRI of the head could be considered. MRI provides the most accurate method for investigating non-synchronous pulsatile tinnitus to exclude significant and/or treatable disease. The committee noted that the incidence of this medical condition is very low. Again, where MRI is not suitable, contrast enhanced CT of the head should be considered, although the risk from radiation dose and potential for adverse reaction to the contrast media means that MRI is preferred where possible.
1.8.1.4. Cost effectiveness and resource use
There were no economic evaluations available for this review question. The view of the committee was that all people with pulsatile tinnitus should be offered a scan because pulsatile tinnitus can occur due to serious causes such as irregular blood vessels, high blood pressure, raised intracranial pressure, anaemia and atherosclerosis, paragangliomas, osseous pathology and glomus tumours. A scan would be able to help identify the underlying cause of tinnitus and avoid later expenditure and morbidity that might occur if these conditions were left untreated.
The committee judged that a scan was imperative for the pulsatile tinnitus population but they were also mindful of the potential resource impact. One way that the committee considered cost-effectiveness in their recommendations is by ensuring clinicians are directed towards the most appropriate tests and thereby limiting unnecessary use of more expensive imaging modalities such as an MRI. For example, the committee has recommended using a contrast CT as the primary imaging test in people suspected for an osseous or middle ear abnormality.
Synchronous pulsatile tinnitus
The committee noted that examinations and audiological assessments may indicate suspicion of osseous or middle ear abnormality in people with synchronous pulsatile tinnitus. In these cases, the committee formed a consensus view that a contrast-enhanced CT scan of the temporal bone would be the preferred and more sensitive imaging modality for this abnormality. The committee were of the view that this recommendation would aid in preventing clinicians immediately opting for the more expensive MRI scan and thus help generate cost-savings.
In those instances where there are no such suspicions but a person has synchronous pulsatile tinnitus, the committee formed a consensus view that an MRA or MRI of head, neck, temporal bone and IAM should be provided. This is because in these cases, MRI and MRA imaging techniques are more able to pick up soft tissue, vascular and other abnormalities and are associated with less harm than CT. The committee suggested that a CT of head, neck, temporal bone and IAM should however be used if MRI or MRA is not possible or cannot be tolerated. While a CT scan would be less sensitive than the MRA, the committee noted that it was still important for clinicians to rule out significant pathology as this would reduce later expenditure and avoidable complications.
The committee noted that the consensus recommendations on imaging modalities for synchronous tinnitus has the potential to be cost saving because it will limit the unnecessary use of more expensive imaging modalities (e.g. MRA or MRI).
Non-synchronous pulsatile tinnitus
Current practice for investigating non-synchronous pulsatile tinnitus is for an MRI of the head to be performed in cases where palatal myoclonus is thought to be the cause of the tinnitus. Therefore, the recommendation is not a change to practice and is expected to be cost-neutral to the NHS. Again, the committee noted that it was important all people with non-synchronous tinnitus are considered for imaging (preferably an MRI of the head or CT of the head if an MRI is contraindicated) to prevent avoidable complications and later expenditure.
1.8.2. Other factors the committee took into account
Whilst individuals may become anxious whilst waiting for scans and results, the clinician can minimise this anxiety by discussing openly the reasons for the scan, the risks and benefits of the scan and the possible outcomes. Most people with pulsatile tinnitus will appreciate having an investigation which will either indicate a condition to be treated or rule out any serious underlying cause for the tinnitus.
The committee noted that MRI is loud and some people may find this noise can affect their tinnitus. Radiology departments provide earplugs, if this is the case.
References
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- Dawes PJ, Basiouny HE. Outcome of using magnetic resonance imaging as an initial screen to exclude vestibular schwannoma in patients presenting with unilateral tinnitus. Journal of Laryngology and Otology. 1999; 113(9):818–22 [PubMed: 10664684]
- 2.
- De Ridder D, De Ridder L, Nowe V, Thierens H, Van De Heyning P, Moller A. Pulsatile tinnitus and the intrameatal vascular loop: Why do we not hear our carotids? Neurosurgery. 2005; 57(6):1213–1217 [PubMed: 16331169]
- 3.
- Fortnum H, O’Neill C, Taylor R, Lenthall R, Nikolopoulos T, Lightfoot G et al. The role of magnetic resonance imaging in the identification of suspected acoustic neuroma: A systematic review of clinical and cost-effectiveness and natural history. Health Technology Assessment. 2009; 13(18) [PubMed: 19358774]
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- Mundada P, Singh A, Lingam RK. CT arteriography and venography in the evaluation of pulsatile tinnitus with normal otoscopic examination. Laryngoscope. 2015; 125(4):979–984 [PubMed: 25379666]
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- National Institute for Health and Care Excellence. Developing NICE guidelines: the manual [Updated October 2018] London. National Institute for Health and Care Excellence, 2014. Available from: https://www
.nice.org .uk/process/pmg20/chapter /introduction-and-overview - 6.
- NHS Improvement. NHS reference costs 2017-18. 2017. Available from: https://improvement
.nhs .uk/resources/reference-costs/#rc1718 Last accessed: 29/05/19 - 7.
- Remley KB, Coit WE, Harnsberger HR, Smoker WR, Jacobs JM, McIff EB. Pulsatile tinnitus and the vascular tympanic membrane: CT, MR, and angiographic findings. Radiology. 1990; 174(2):383–9 [PubMed: 2296650]
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- Seemann MD, Beltle J, Heuschmid M, Lowenheim H, Graf H, Claussen CD. Image fusion of CT and MRI for the visualization of the auditory and vestibular system. European Journal of Medical Research. 2005; 10(2):47–55 [PubMed: 15817422]
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- Simonetti P, Oiticica J. Tinnitus neural mechanisms and structural changes in the brain: The contribution of neuroimaging research. International Archives of Otorhinolaryngology. 2015; 19(3):259–265 [PMC free article: PMC4490922] [PubMed: 26157502]
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- Song JJ, De Ridder D, Van De Heyning P, Vanneste S. Mapping tinnitus-related brain activation: An activation-likelihood estimation metaanalysis of PET studies. Journal of Nuclear Medicine. 2012; 53(10):1550–1557 [PubMed: 22917883]
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- Waldvogel D, Mattle HP, Sturzenegger M, Schroth G. Pulsatile tinnitus - A review of 84 patients. Journal of Neurology. 1998; 245(3):137–142 [PubMed: 9553842]
Appendices
Appendix A. Review protocols
Table 3. Review protocol: Imaging method to investigate the cause of pulsatile tinnitus (PDF, 356K)
Appendix B. Literature search strategies
The literature searches for this review are detailed below and complied with the methodology outlined in Developing NICE guidelines: the manual.5
For more detailed information, please see the Methodology Review.
B.1. Clinical search literature search strategy
Searches were constructed using a PICO framework where population (P) terms were combined with Intervention (I) and in some cases Comparison (C) terms. Outcomes (O) are rarely used in search strategies for interventions as these concepts may not be well described in title, abstract or indexes and therefore difficult to retrieve. Search filters were applied to the search where appropriate.
Table 5. Database date parameters and filters used
B.2. Health Economics literature search strategy
Health economic evidence was identified by conducting a broad search relating to the tinnitus population in NHS Economic Evaluation Database (NHS EED – this ceased to be updated after March 2015) and the Health Technology Assessment database (HTA) with no date restrictions. NHS EED and HTA databases are hosted by the Centre for Research and Dissemination (CRD). Additional searches were run on Medline and Embase for health economics and quality of life studies.
Appendix C. Clinical evidence selection
Appendix D. Clinical evidence tables
No evidence identified.
Appendix E. Forest plots
No evidence identified.
Appendix F. GRADE tables
No evidence identified.
Appendix G. Health economic evidence selection
Figure 2. Flow chart of health economic study selection for the guideline
Appendix H. Excluded studies
H.1. Excluded clinical studies
H.2. Excluded health economic studies
None.
Appendix I
This appendix is not available from the publisher at this time.
Final
Diagnostic test and treat evidence review
This evidence review was developed by the National Guideline Centre
Disclaimer: The recommendations in this guideline represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, professionals are expected to take this guideline fully into account, alongside the individual needs, preferences and values of their patients or service users. The recommendations in this guideline are not mandatory and the guideline does not override the responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and, where appropriate, their carer or guardian.
Local commissioners and providers have a responsibility to enable the guideline to be applied when individual health professionals and their patients or service users wish to use it. They should do so in the context of local and national priorities for funding and developing services, and in light of their duties to have due regard to the need to eliminate unlawful discrimination, to advance equality of opportunity and to reduce health inequalities. Nothing in this guideline should be interpreted in a way that would be inconsistent with compliance with those duties.
NICE guidelines cover health and care in England. Decisions on how they apply in other UK countries are made by ministers in the Welsh Government, Scottish Government, and Northern Ireland Executive. All NICE guidance is subject to regular review and may be updated or withdrawn.
- Review Evidence review for imaging to investigate the cause of non-pulsatile tinnitus: Tinnitus: assessment and management: Evidence review J[ 2020]Review Evidence review for imaging to investigate the cause of non-pulsatile tinnitus: Tinnitus: assessment and management: Evidence review JNational Guideline Centre (UK). 2020 Mar
- Review Imaging of tinnitus: a review.[Radiology. 2000]Review Imaging of tinnitus: a review.Weissman JL, Hirsch BE. Radiology. 2000 Aug; 216(2):342-9.
- Review Detecting causes of pulsatile tinnitus on CT arteriography-venography: A pictorial review.[Eur J Radiol. 2021]Review Detecting causes of pulsatile tinnitus on CT arteriography-venography: A pictorial review.Kumar R, Rice S, Lingam RK. Eur J Radiol. 2021 Jun; 139:109722. Epub 2021 Apr 14.
- [Pulsatile tinnitus. Causes, diagnostic procedures, case presentation].[Laryngorhinootologie. 1991][Pulsatile tinnitus. Causes, diagnostic procedures, case presentation].Mahlo HW, Kellermann S. Laryngorhinootologie. 1991 Dec; 70(12):675-7.
- Review [Pulsating tinnitus].[Wien Klin Wochenschr. 2000]Review [Pulsating tinnitus].Reiss M, Reiss G. Wien Klin Wochenschr. 2000 Jan 28; 112(2):84-91.
- Evidence review for imaging to investigate the cause of pulsatile tinnitusEvidence review for imaging to investigate the cause of pulsatile tinnitus
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