Imaging of dizziness

Cerebral blood flow in patients recovered from mild COVID-19

BACKGROUND AND PURPOSE

Cerebral hypoperfusion has been described in both severe and mild forms of symptomatic Coronavirus Disease 2019 (COVID-19) infection. The purpose of this study was to investigate global and regional cerebral blood flow (CBF) in asymptomatic COVID-19 patients.

METHODS

Cases with mild COVID-19 infection and age-, sex-, and race-matched healthy controls were drawn from the Aging Brain Consortium at The University of South Carolina data repository. Demographics, risk factors, and data from the Montreal Cognitive Assessment were collected. Mean CBF values for gray matter (GM), white matter (WM), and the whole brain were calculated by averaging CBF values of standard space-normalized CBF image values falling within GM and WM masks. Whole brain region of interest-based analyses were used to create standardized CBF maps and explore differences between groups.

RESULTS

Twenty-eight cases with prior mild COVID-19 infection were compared with 28 controls. Whole-brain CBF (46.7 ± 5.6 vs. 49.3 ± 3.7, p = .05) and WM CBF (29.3 ± 2.6 vs. 31.0 ± 1.6, p = .03) were noted to be significantly lower in COVID-19 cases as compared to controls. Predictive models based on these data predicted COVID-19 group membership with a high degree of accuracy (85.2%, p < .001), suggesting CBF patterns are an imaging marker of mild COVID-19 infection.

CONCLUSION

In this study, lower WM CBF, as well as widespread regional CBF changes identified using quantitative MRI, was found in mild COVID-19 patients. Further studies are needed to determine the reliability of this newly identified COVID-19 brain imaging marker and determine what drives these CBF changes.

The Vestibulocochlear Nerve: Anatomy and Pathology

The vestibulocochlear nerve is the eighth cranial nerve, entering the brainstem in the medullopontine sulcus after crossing the internal auditory canal and cerebellopontine angle cistern. It is a purely sensitive nerve, originating from the Scarpa's and spiral ganglions, responsible for balance and hearing. It has 6 nuclei located in the lower pons. Magnetic resonance imaging (MRI) is useful for evaluating the vestibulocochlear nerve, although computed tomography may have a complementary role in assessing bone lesions. A heavily T2-weighted sequence, such as fast imaging employing steady-state acquisition (FIESTA) or constructive interference steady state (CISS), is crucial in imaging exams to depict the canalicular and cisternal segments of the vestibulocochlear nerve, as well as the fluid signal intensity in the membranous labyrinth. The vestibulocochlear nerve can be affected by several diseases, such as congenital malformations, trauma, inflammatory or infectious diseases, vascular disorders, and neoplasms. The purpose of this article is to review the vestibulocochlear nerve anatomy, discuss the best MRI techniques to evaluate this nerve and demonstrate the imaging aspect of the main diseases that affect it.

Use of Neuroimaging for Patients With Dizziness Who Present to Outpatient Clinics vs Emergency Departments in the US

Importance

Overuse of costly neuroimaging technology is associated with low-value care for the prevalent symptom of dizziness. Although quality improvement initiatives have focused on the overuse of computed tomography (CT) scans in emergency departments (EDs), most patients with dizziness present to outpatient clinics. To inform practice and policy, a comprehensive understanding of the uses and costs of neuroimaging across settings and episodes of care is needed.

Objective

To characterize neuroimaging use, timing, and spending as well as factors associated with imaging acquisition within 6 months of presentation for dizziness in outpatient vs ED settings.

Design, Setting, and Participants

This cross-sectional study of commercial and Medicare Advantage claims for 805 454 adults (≥18 years of age) with new diagnoses of dizziness was conducted from January 1, 2006, through December 31, 2015. Data were analyzed from October 1, 2020, to September 30, 2021.

Main Outcomes and Measures

Use of neuroimaging (CT scan, magnetic resonance imaging [MRI], angiography, and ultrasonography) and total spending on neuroimaging were measured. Kaplan-Meier analysis was performed. The associations of neuroimaging with setting, sociodemographic characteristics, and clinicians were estimated with multivariable analyses.

Results

A total of 805 454 individuals with dizziness (502 055 women [62%]; median age, 52 years [range, 18-87 years]) were included in this study; 156 969 (20%) underwent neuroimaging within 6 months of presentation (65 738 of 185 338 [36%] presented to EDs and 91 231 of 620 116 [15%] presented to outpatient clinics). The median time to neuroimaging was 0 days (95% CI, 0-2 days) after ED presentation and 10 days (95% CI, 9-10 days) after outpatient presentation. Neuroimaging was independently associated with advanced age, comorbidity, race and ethnicity, ED presentation, and outpatient clinician specialty. Across sites, a head CT scan was the most used test on presentation date (92% of tests [46 852 of 51 022]). Within 6 months of presentation, a head CT scan was the most used test (47% of all tests [177 949 of 376 149]), followed by brain MRI (25% [93 130 of 376 149]), cerebrovascular ultrasonography (15% [56 175 of 376 149]), and magnetic resonance angiography (9% [34 026 of 376 149]). Of $88 646 047.03 in total neuroimaging spending, MRI accounted for 70% ($61 730 251.95), CT scans for 19% ($16 910 506.24), and ultrasonography for 11% ($10 005 288.84). Per-test median spending ranged from $68.97 (CT scan of the head) to $319.63 (MRI of the brain) among commercially insured individuals and $43.21 (CT scan of the head) to $362.02 (MRI of the orbit, face, and neck) among Medicare Advantage beneficiaries.

Conclusions and Relevance

The findings of this cross-sectional study suggest that use of neuroimaging for dizziness is prevalent across settings. Interventions to optimize the use of neuroimaging must occur early in the patient care journey to discourage guideline-discordant use of CT scans, advocate for judicious MRI use (particularly in ambulatory settings), and account for the effects of price transparency.

Limited usefulness of routine head and neck CT angiogram in the imaging assessment of dizziness in the emergency department

OBJECTIVE

To assess the usefulness of head and neck computed tomography angiogram for the investigation of isolated dizziness in the emergency department in detecting significant acute findings leading to a change in management in comparison to non-contrast computed tomography scan of the head.

METHODS

Patients presenting with isolated dizziness in the emergency department investigated with non-contrast computed tomography and computed tomography angiogram over the span of 36 months were included. Findings on non-contrast computed tomography were classified as related to the emergency department presentation versus unrelated/no significant abnormality. Similarly, computed tomography angiogram scans were classified as positive or negative posterior circulation findings.

RESULTS

One hundred and fifty-three patients were imaged as a result of emergency department presentation with isolated dizziness. Fourteen cases were diagnosed clinically as of central aetiology. Non-contrast computed tomography was positive in three patients, all with central causes with sensitivity 21.4%, specificity 100%, positive predictive value 100%, negative predictive value 92.6% and accuracy 92.8%. Computed tomography angiogram was positive for angiographic posterior circulation abnormalities in five cases, and only two of them had a central cause of dizziness, with sensitivity 14.3%, specificity 97.7%, positive predictive value 40%, negative predictive value 91.46% and accuracy 92.1%.

CONCLUSION

Both non-contrast computed tomography and computed tomography angiogram of the head and neck have low diagnostic yield for the detection of central causes of dizziness, However, non-contrast computed tomography has higher sensitivity and positive predictive value than computed tomography angiogram, implying a lack of diagnostic advantage from the routine use of computed tomography angiogram in the emergency department for the investigation of isolated dizziness. Further studies are required to determine the role of computed tomography angiogram in the work-up of isolated dizziness in the emergency department.

Economic burden of vertigo: a systematic review

BACKGROUND

Vertigo, a highly prevalent disease, imposes a rising burden on the health care system, exacerbated by the ageing of the population; and further, contributes to a wide span of indirect burden due to reduced capacity to work or need of assistance in activities of daily living. The aim of this review was to summarise the evidence on the economic burden of vertigo.

METHODS

All original studies published between 2008 and 2018 about the economic evaluation of peripheral or central vestibular vertigo in developed countries were considered eligible, unrestricted to setting, health care provider, or study type.

RESULTS

The electronic search in three databases identified 154 studies from which 16 qualified for inclusion. All studies presented partial economic evaluation referring to a variety of vestibular vertigo including unspecified vertigo. Nine studies presented monetised cost results and seven studies reported health care utilization. Direct costs derived mainly from repeated and not well-targeted consultations at all levels of health care, excessive use of diagnostic imaging, and/or of emergency care. Considerable societal burden was caused by decreased productivity, mainly due to work absenteeism.

CONCLUSION

To the best of our knowledge, this is the first systematic review of the existing evidence of the economic burden of vertigo. The lack of conclusive evidence revealed apparent targets of future research. First, studies of diagnostics and therapies for vestibular disease should include cost-effectiveness considerations. Population-based studies of health services utilization should include simple vestibular assessments to get more reliable estimates of the burden of disease and associated costs on the level of the general population. Further, clinical and population-based registries that include patients with vestibular disease, should consider collecting long-term data of societal burden. Primary data collection should increasingly include assessment of health care utilization e.g. by linking their diagnoses and outcomes to routine data from health insurances.

Cervical spine radiographs in patients with vertigo and dizziness

OBJECTIVE

The purpose of this study is to investigate the role of cervical radiography in the study of patients with vertigo and dizziness.

PATIENTS

This is a retrospective single-institution case series study of 493 patients suffering from vertigo and dizziness who were referred (from January 2011 to December 2012) to the hospital to study those symptoms.

METHODS

We studied cervical radiographies, CT and MRI of the cervical spine made in the sample and the radiological findings. We analyzed demographic characteristics, presence of psychiatric pathology and emergency assistance due to vertigo in patients who have undergone cervical study.

RESULTS

A total of 57% of patients had cervical radiography made; this was more frequent in women, Spanish people, with psychiatric pathology and who have gone to the emergency department for vertigo (p < 0.05). Degenerative changes were found in 74.1% of the patients with radiography made, more frequently at an older age, osteophytes in 49.5% and abnormal cervical lordosis in 37.1%.

CONCLUSIONS

There are sociodemographic factors that influence in the request for cervical radiographs in patients with vertigo and dizziness. Given the suspicion of cervical vertigo, we do not consider that the findings in the radiographs help in the diagnosis. In our opinion, an excessive use of cervical radiography is made in patients with vertigo and dizziness.

The diagnostic challenge of dizziness: computed tomography and magnetic resonance imaging findings

Dizziness is a prevalent symptom in the general population, accounting for a considerable share of physician office visits, and most causes are clinically treatable. It is also a common indication for neuroimaging studies, in order to identify a specific etiology and exclude surgical causes. Here, we illustrate the main peripheral and central causes of dizziness, discussing their possible differential diagnoses, as well as their most important image aspects.