Regional Mechanical Thrombectomy Imaging Protocol in Patients Presenting with Acute Ischemic Stroke during the COVID-19 Pandemic.

BACKGROUND AND PURPOSE: Chest CT is a rapid, useful additional screening tool for coronavirus disease 2019 (COVID-19) in emergent procedures. We describe the feasibility and interim outcome of implementing a modified imaging algorithm for COVID-19 risk stratification across a regional network of primary stroke centers in the work-up of acute ischemic stroke referrals for time-critical mechanical thrombectomy. MATERIALS AND METHODS: We undertook a retrospective review of 49 patients referred to the regional neuroscience unit for consideration of mechanical thrombectomy between April 14, 2020, and May 21, 2020. During this time, all referring units followed a standard imaging protocol that included a chest CT in addition to a head CT and CT angiogram to identify Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) infective pulmonary changes. RESULTS: Overall, 2 patients had typical COVID-19 radiologic features and tested positive, while 7 patients had indeterminate imaging findings and tested negative. The others had normal or atypical changes and were not diagnosed with or suspected of having COVID-19. There was an overall sensitivity of 100%, specificity of 74.1%, negative predictive value of 100%, and positive predictive value of 22.2% when using chest CT to diagnose COVID-19 in comparison with the real-time reverse transcriptase-polymerase chain reaction test. The mean additional time and radiation dose incurred for the chest CT were 184 ± 65.5 seconds and 2.47 ± 1.03 mSv. Multiple cardiovascular and pulmonary incidental findings of clinical relevance were identified in our patient population. CONCLUSIONS: Chest CT provides a pragmatic, rapid additional tool for COVID-19 risk stratification among patients referred for mechanical thrombectomy. Its inclusion in a standardized regional stroke imaging protocol has enabled efficient use of hospital resources with minimal compromise or delay to the overall patient treatment schedule.

Outcome of embolised vascular metastatic renal cell tumours causing spinal cord compression.

PURPOSE: To present the results of the surgical management of metastatic renal cell tumours of the spine with cord compression who underwent pre-operative embolisation. METHODS: We conducted a retrospective cohort study of all embolised vascular metastatic renal cell tumours of the spine that underwent urgent surgical intervention over a 7-year period (2005-2011). All medical notes, images and angiography/embolisation details were studied. We recorded the timing (immediate vs. delayed) and grade of embolisation and compared this to the estimated blood loss (EBL); extent of metastatic spinal cord compression (using the Tomita score and Bilsky scores) was also compared to EBL. Finally, neurological (Frankel grade), surgical outcome and complications were reviewed in all patients. RESULTS: During the study period, we operated on 25 emergency patients with metastatic renal cell carcinoma causing spinal cord compression who had received pre-operative embolisation (mean age 59.6 (24-78) years; 8 females, 17 males). All but one of our patients had hypervascularisation/arterio-venous fistulae on angiography. We were able to achieve greater than 90 % embolisation in the majority (17/25, 68 %) The estimated blood loss was 1,696 (400-5,000) ml; mean operating time was 276 (90-690) min and an average of 2.3 (0-7) units of whole blood was transfused. Nine patients had a posterior only decompression/stabilisation, nine patients had a posterior decompression ± cement augmentation, six had combined anterior/posterior procedures and one had anterior corpectomy/reconstruction alone. There was no statistical difference in the EBL between immediate versus delayed surgery after embolisation or the grade of embolisation. Immediate surgery after embolisation and interestingly less complete embolisation showed a trend towards less EBL. The extent of the tumour as graded by the Bilsky score correlated with increased EBL (p = 0.042). No complications occurred during the embolisation procedure. The surgical complication rate was 32 % (8/25) including two major complications (septicaemia (1) and metal work failure (2)) and five minor complications. Postoperatively, 52 % (13/25) had no change in neurological status, 36 % (9/25) improved by at least one Frankel grade and 12 % (3/25) had neurological deterioration by one Frankel grade. The average survival following surgery was 14.1 (0.5-72) months. CONCLUSION: Blood loss (mean 1,696 ml) and complications (32 %) remain a concern in the operative treatment of vascular metastatic spinal cord compression. Most patients remained the same neurologically or improved by at least 1 grade (22/25, 88 %). Paradoxically, greater embolisation showed a trend to more blood loss which could be due to more extensive surgery in this group, a rebound 'reperfusion' phenomena or even the presence of arterio-venous fistulae. Interestingly, we also found that the extent of the tumour, as graded by the Bilsky score, correlated with increased blood loss suggesting that more extensive cord compression by metastases could lead to more blood loss intra-operatively.

Primary care direct access MRI for the investigation of chronic headache.

AIM: To assess the efficacy of a primary-care imaging pathway for neurology outpatients, from inception to deployment, compared with traditional outpatient referral. MATERIALS AND METHODS: After local agreement, guidelines were generated providing pathways for diagnosis and treatment of common causes of headache, highlighting "red-flag" features requiring urgent neurology referral, and selecting patients for direct magnetic resonance imaging (MRI) referral. In addition, reports were clarified and standardized. To evaluate the efficacy of the access pathway, a retrospective sequential review of 100 MRI investigations was performed comparing general practitioner (GP) referral, with traditional neurology referral plus imaging, acquired before the pathway started. RESULTS: No statistically significant difference in rates of major abnormalities, incidental findings or ischaemic lesions were identified between the two cohorts. Reported patient satisfaction was high, with a cost reduction for groups using the pathway. CONCLUSION: The findings of the present study suggest that a defined access pathway for imaging to investigate chronic headache can be deployed appropriately in a primary-care setting.

The role of magnetic resonance imaging in the identification of suspected acoustic neuroma: a systematic review of clinical and cost effectiveness and natural history.

OBJECTIVE(S): To evaluate the clinical effectiveness and cost-effectiveness of a range of diagnostic strategies for investigating patients with unilateral hearing loss and/or tinnitus, with a view to confirming or eliminating a diagnosis of acoustic neuroma, and to describe the natural history of acoustic neuroma. DATA SOURCES: Major electronic databases were searched from January 1980 to August 2008. REVIEW METHODS: Selected studies were assessed and subjected to data extraction and quality assessment using standard methods. RESULTS: Studies comparing auditory brainstem response (ABR) with magnetic resonance (MR) imaging were highly heterogeneous. ABR has high sensitivity compared with MR imaging for acoustic neuromas greater than 1 cm in size but not for smaller neuromas. The sensitivities of T2-weighted (T2W) and T2-star-weighted (T2*W) imaging strategies compared with gadolinium-enhanced T1-weighted (GdT1W) MR imaging (gold standard) were high and relatively homogeneous. The specificity of T2W and T2*W studies ranged from 90% to 100% and from 86% to 99% respectively. The review of cost-effectiveness showed that GdT1W MR imaging immediately or in conjunction with ABR appears to be more cost-effective than 'traditional' protocols; ABR/GdT1W MR imaging protocols were more cost-effective than going directly to GdT1W MR imaging. Non-contrast-enhanced MR imaging was found to be a more cost-effective test for acoustic neuroma than GdT1W MR imaging. The incidence of acoustic neuroma has increased over the last 30 years, with the median age at diagnosis remaining at 55 years. Most patients present with insidious symptoms of unilateral hearing impairment, tinnitus and/or vertigo. The pattern and rate of growth of acoustic neuroma are highly variable and currently unpredictable. At least 50% of tumours do not grow, at least for some years after diagnosis. Some studies have found large initial size to be a determinant of later growth, with the opposite also being reported. The mean growth rate for all tumours varies between 1 and 2 mm/year, with a rate of 2-4 mm/year for only those that grow; however, there are cases with significant regression (5%) or exceptional growth (which may exceed 18 mm/year). CONCLUSIONS: The majority of the evidence reviewed was poorly reported and there is therefore an inherent risk of bias. Given the recent improvement in resolution and reduction in cost of MR imaging, ABR can no longer be considered appropriate as the primary test used to screen for acoustic neuroma. T2W or T2*W sequences enable accurate evaluation of the VIIIth and VIIth cranial nerves within the cerebellopontine angle and internal auditory canal as well as evaluation of the cochlea and labyrinth, and inclusion of GdT1W sequences is unlikely to contribute information that would alter patient management in the screening population. The quality of the imaging chain and experience of the reporting radiologist are key factors determining the efficacy of a non-contrast screening strategy. Based on a cost-effectiveness model developed to reflect UK practice it was concluded that a diagnostic algorithm that deploys non-contrast MR imaging as an initial imaging screen in the investigation of acoustic neuroma is less costly than and likely to be as effective as available contrast MR imaging.

Cerebral manifestations in liver disease and transplantation.

Patients with liver disease frequently develop cerebral complications. The brain may be affected directly by the pathological process or agent responsible for the liver disease, as a consequence of the metabolic and haemodynamic derangement caused by hepatic dysfunction, or as a complication of the treatment of liver disease. Computed tomography (CT) and magnetic resonance imaging (MRI) can be helpful in the diagnosis and management of these complications, and advanced techniques such as diffusion weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) are providing new insights into the underlying pathophysiological processes. We present a radiological overview of the cerebral manifestations of liver disease, categorized as acute presentations, chronic presentations, and conditions occurring in the context of liver transplantation.

Imaging of acute neurological conditions in pregnancy and the puerperium.

Eclampsia is one of the most common acute neurological events occurring during pregnancy. However, there are many other conditions that can present during pregnancy and the puerperium and that may either mimic eclampsia or produce other acute neurological manifestations. Frequently the symptoms and signs are non-specific, and it can be difficult to differentiate between these conditions on clinical grounds alone. Neuroradiological studies can provide valuable diagnostic information, and interventional radiological procedures may play a part in the subsequent management of these conditions. This review focuses on the imaging of acute neurological conditions which may be associated with, or present during, pregnancy and the puerperium.

Internal carotid artery dissection presenting with ipsilateral tenth and twelfth nerve palsies and apparent mass lesion on MRI.

We report the case of a 47-year-old man who presented with a few months' history of right-sided headache and dysphagia, with ipsilateral tenth and twelfth cranial nerve palsies on examination. The initial MRI showed an enhancing mass lesion in relation to the right carotid sheath and jugular foramen, and was reported as a possible paraganglioma. Subsequent angiography performed to assess tumour vascularity demonstrated a dissection involving a tonsillar loop of the right internal carotid artery (ICA). Imaging findings at MRI and angiography and the presentations and mechanisms of ICA dissection are briefly discussed.

Aneurysmal sub-arachnoid haemorrhage in patients with Noonan syndrome: a report of two cases and review of neurovascular presentations in this syndrome.

To date, intracranial aneurysms have been reported in two patients with Noonan syndrome. We report two unrelated patients with Noonan syndrome who presented with sub-arachnoid haemorrhage secondary to intracranial aneurysms. These cases are discussed and other cerebrovascular abnormalities that have been described in association with Noonan syndrome are reviewed. Ultrastructural and genetic factors contributing to these associations are considered.

Third ventricular plasma-cell lesion with delayed intraventricular transudation of contrast medium.

We report a patient presenting with hydrocephalus secondary to a posterior third ventricular plasma-cell lesion which exhibited delayed transudation of contrast medium into the adjacent aqueduct and fourth ventricle.