Micro-balloon-assisted embolization of anterior cranial fossa dural arteriovenous fistula via a trans-ophthalmic approach - a technical report and case series.

PURPOSE: Dural arteriovenous fistulas (dAVF) account for approximately 10-15% of all intracranial arteriovenous abnormalities. dAVFs carry a significant risk of mortality, particularly in cases of acute hemorrhage, of up to 10%. A small proportion of these dAVFs are found in the anterior cranial fossa (ACF), of which the rate of hemorrhage can be as high as up to 91%. The Scepter Mini (SM) is the smallest dual-lumen micro-balloon (MB) available for neurointerventional practice. It consists of a 2.8 French outer diameter, with a 2.2 mm × 9 mm semi-compliant balloon providing a working length of 165 cm. The SM is navigated with a 0.008-inch wire making it a particularly attractive tool accessible to the pedicles normally reached with liquid embolization micro-catheters. METHODS: Five consecutive patients over a 1-year period between 2020 and 2021 were evaluated and treated for ACF dAVF using a liquid embolization approach using the SM balloon. All patients were treated using ethylene-vinyl alcohol copolymer (EVOH), of which Squid 18 and/or Squid 12 were the chosen viscosities. Control angiograms were performed for all patients post-embolization. RESULTS: All patients demonstrated complete occlusion of the ACF dAVF on immediate post-treatment angiography. No immediate complications were encountered; particularly, there were no reports of visual field deficit in any of the patients. CONCLUSION: The MB is a valuable adjunctive tool that can enhance the safety and efficacy of trans-ophthalmic embolization of ACF dAVFs, providing additional protection to the retinal and posterior ciliary arteries against unwanted reflux of liquid embolic agent.

Foetal radiation exposure caused by mechanical thrombectomy in large-vessel ischaemic stroke in pregnancy.

PURPOSE: There is overwhelming evidence for the clinical benefits that are derived following mechanical thrombectomy in large-vessel acute ischaemic stroke. The risk of stroke is elevated in pregnancy due to many factors. To date, there have been two reports, totalling five patients, who have undergone mechanical thrombectomy in pregnancy, thus demonstrating the feasibility of the procedure; however, there is no data on the radiation exposure to the mother or foetus related to this therapy. METHODS: We highlight the important technical considerations to minimise the risk of the procedure and report the estimated dose received by mother and foetus. We also compare these doses with those received during whole-body CT in trauma and CT pulmonary angiogram (CTPA) examinations. RESULTS: Three cases of mechanical thrombectomy were performed at separate tertiary referral neuroscience centres in the UK. Following diagnostic CT and mechanical thrombectomy, the total whole-body effective dose to the pregnant patient was significantly higher than in patients undergoing CTPA (p < 0.05), but not significant different compared to whole-body CT imaging in trauma patients. The estimated dose received by the foetus following diagnostic CT and mechanical thrombectomy was significantly lower than in whole-body imaging in trauma patients at p < 0.05, with no difference in estimated foetal dose compared to CTPA imaging. CONCLUSION: The estimated doses received by the foetus during diagnostic stroke imaging and mechanical thrombectomy are equivalent to, or less than, purely diagnostic imaging in emergency situations.

Ruptured intracranial dermoid cysts: a pictorial review.

Intracranial dermoid cysts are rare, benign, congenital, slow-growing cystic lesions. They are composed of mature squamous epithelium and can contain apocrine, eccrine, and sebaceous glands as well as other exodermal structures. Rupture of intracranial dermoid cysts is a relatively uncommon phenomenon but can cause more serious complications such as chemical meningitis, vasospasm, and cerebral infarction. Understanding of the appearance of both unruptured and ruptured dermoid cysts on computed tomography and MRI, especially awareness of existing low signal "blooming artefacts" on certain sequences, aids diagnosis and referral to the proper specialty for appropriate treatment.

Vascular and plaque imaging with ultrasmall superparamagnetic particles of iron oxide.

Cardiovascular Magnetic Resonance (CMR) has become a primary tool for non-invasive assessment of cardiovascular anatomy, pathology and function. Existing contrast agents have been utilised for the identification of infarction, fibrosis, perfusion deficits and for angiography. Novel ultrasmall superparamagnetic particles of iron oxide (USPIO) contrast agents that are taken up by inflammatory cells can detect cellular inflammation non-invasively using CMR, potentially aiding the diagnosis of inflammatory medical conditions, guiding their treatment and giving insight into their pathophysiology. In this review we describe the utilization of USPIO as a novel contrast agent in vascular disease.

Systematic review of mouse kidney transplantation.

A mouse model of kidney transplantation was first described in 1973 by Skoskiewicz et al. Although the mouse model is technically difficult, it is attractive for several reasons: the mouse genome has been characterized and in many aspects is similar to man and there is a greater diversity of experimental reagents and techniques available for mouse studies than other experimental models. We reviewed the literature on all studies of mouse kidney transplantation to report the donor and recipient strain combinations that have been investigated and the resultant survival and histological outcomes. Some models of kidney transplantation have used the transplanted kidney as a life-supporting organ, however, in many studies the recipient mouse's native kidney has been left in situ. Several different combinations of inbred mouse strains have been reported, with varying degrees of injury, survival or tolerance because of haplotype differences. This model has been exceptionally useful as an investigational tool to understand multiple aspects of transplantation including acute rejection, cellular and humoral rejection mechanisms and their treatment. Furthermore, this model has been used to investigate disease mechanisms beyond transplant rejection including intrinsic renal disease and infection-associated pathology.

Successful resuscitation after out-of-hospital cardiac arrest.

A 66-year-old woman presented to the emergency department after a witnessed cardiac arrest, having had compression-only cardiopulmonary resuscitation initiated by her son on the backseat of his car. She was resuscitated in the emergency department for 1 hour before the return of spontaneous circulation. She then underwent primary percutaneous coronary intervention and therapeutic hypothermia. She was discharged without significant neurological deficit. This case illustrates better survival and neurological outcome can be achieved by prompt implementation of a 'chain of survival' interventions and therapeutic hypothermia.

Chronic fusiform extracranial vertebral artery aneurysm with recurrent posterior circulation emboli: Case report and review of the literature.

We report a case of a 64-year-old man with a fusiform right extracranial vertebral artery aneurysm, spanning over half the extra-cranial V2 (foraminal) segment, presenting with recurrent multi-focal posterior circulation embolic ischaemic stroke. The patient was treated with endovascular embolisation of the right vertebral artery to prevent further thrombo-embolic events. Distal and proximal occlusion of the aneurysmal vertebral artery was performed with a micro-vascular plug with partial aneurysm sack embolisation to aid thrombosis and reduce the risk of recanalisation. Two months post procedure MR angiography confirmed successful aneurysm occlusion with no post-procedural complication. The patient returned to his normal independent life. Endovascular treatment with vessel sacrifice is an effective treatment with low morbidity and we believe the MVP device to be a efficacious option in the vertebral artery.

Acute haemorrhage rate in 28,000 Out-of-Hours CT heads.

OBJECTIVES: The aim of this paper is to assess the acute haemorrhage rate in patients who had CT head investigation out-of-hours with and without trauma and compare the rates of haemorrhage between warfarin and DOACs, at a busy teritary teaching hospital. METHODS: All CT heads performed between January 2008 and December 2019 were identified from the radiology information system (RIS) at Sheffield Teaching Hospitals (STH), with the requesting information being available from January 2015. The clinical information was assessed for the mention of trauma or anticoagulation, and the reports were categorised into acute and non-acute findings. RESULTS: Between 2008 and 2019 the number of scans increased by 63%, with scans performed out of hours increasing by 278%. Between 2015 and 2019, the incidence of acute ICH was similar over the 5-year period, averaging at 6.9% and ranging from 6.1 to 7.6%. The rate of detection of acute haemorrhage following trauma was greater in those not anticoagulated (6.8%), compared with patients on anticoagulants such as warfarin (5.2%) or DOACs (2.8%). CONCLUSIONS: Over 12 years, there has been a significant increase in the number of CT heads performed at STH. The rate of ICH has remained steady over the last 5 years indicating a justified increase in imaging demand. However, the incidence of ICH in patients prescribed DOACs is lower than the general population and those on warfarin. ADVANCES IN KNOWLEDGE: This finding in a large centre should prompt discussion of the risk of bleeding with DOACs in relation to CT head imaging guidelines.

Skull base aneurysmal bone cyst presenting with hydrocephalus: progressive residuum obliterated by Gamma Knife stereotactic radiosurgery in a pediatric patient.

Aneurysmal bone cysts (ABCs) are an uncommon entity predominantly encountered in the pediatric population. The skull is rarely involved, but these cysts have been reported to arise in the skull base. Traditional treatment has been with surgery alone; however, there is a gathering body of literature that reports alternative treatments that can achieve long-term disease-free survival. However, these therapies are predominantly directed at peripheral skeletal lesions. To the authors' knowledge, this report is the first to describe long-term follow-up of the efficacy of Gamma Knife stereotactic radiosurgery for treatment of ABC residuum in the skull base that resulted in long-term patient stability and likely ABC obliteration.

Transarterial CT angiography for surgical planning of spinal dural arteriovenous fistula.

OBJECTIVE: We report a novel method to provide excellent anatomical depiction of a dural arteriovenous fistula (dAVF) for surgical planning. METHODS: A 78-year-old female presented with progressive back pain, deteriorating mobility and urinary incontinence with a background of obesity and severe osteoarthritis. Initial MRI suspected dAVF and subsequent spinal angiography encountered an extremely tortuous and arteriosclerotic aorta, hence catheterisation of the segmental-intercostal and lumbar vessels proved challenging. Contrast injection into the aortic arch via a pigtail catheter for arterial-phase CT angiogram of the descending aorta was performed. RESULTS: This modality of imaging delineated the dAVF showing extensive involvement of the whole spine accounting for the patient's symptoms. Furthermore this allowed characterisation of bony anatomy in relation to the fistula facilitating precise surgical approach. The dAVF was successfully disconnected through a localised laminectomy centred over the lesion. CONCLUSION: This specific technique for dAVF characterisation has not been previously reported, although trans-venous angiography has been used to some effect. In view of diagnostic and therapeutic technical difficulties that are often faced in such patients, this technique may be a useful alternative that is not only helpful in accurate diagnosis but helps in providing an invaluable guide for the surgical approach. ADVANCES IN KNOWLEDGE: This case highlights the difficulties that one may be faced within cases of tortuous vasculature and the obese patient population. With this in mind we demonstrate how a unique hybridised technique may provide valuable alternative to the neurosciences team should such a future scenario arise.

Mechanical thrombectomy for acute stroke in pregnancy.

Several recent randomised control trials have shown adjunctive endovascular mechanical thrombectomy to be an effective and safe treatment for acute stroke superior to medical therapy alone. Despite this, questions remain over certain groups of patients that have been excluded from these studies, such as pregnant women. We believe this is a topic of increasing clinical significance with minimal data in the literature. In this article we discuss stroke in pregnancy and highlight the important technical considerations of endovascular mechanical thrombectomy, including minimising radiation exposure to the mother and fetus.

A Pictorial Review of Intracranial Haemorrhage Revisited.

BACKGROUND: The many causes of Intracerebral Haemorrhage (IH) can be difficult to differentiate. However, there are imaging features that can provide useful clues. This paper aims to provide a pictorial review of the common causes of IH, to identify some distinguishing diagnostic features and to provide guidance on subsequent imaging and follow up. It is hoped that this review would benefit radiology and non-radiology consultants, multi-professional workers and trainees who are commonly exposed to unenhanced CT head studies but are not neuroradiology specialists. DISCUSSION: In the absence of trauma, Spontaneous Intracerebral Haemorrhage (SIH) can be classified as idiopathic or secondary. Secondary causes of IH include hypertension and amyloid angiopathy (75-80%) and less common pathologies such as vascular malformations (arteriovenous malformations, aneurysms and cavernomas), malignancy , venous sinus thrombosis and infection. SIH causes between 10 to 15% of all strokes and has a higher mortality than ischaemic stroke. Trauma is another cause of IH with significant mortality and some of the radiological features will be reviewed. CONCLUSION: Unenhanced CT is a mainstay of acute phase imaging due to its availability and, sensitivity and specificity for detecting acute haemorrhage. Several imaging features can be identified on CT and, along with clinical information, can provide some certainty in diagnosis. For those suitable and where diagnostic uncertainty remains CT angiogram, time-resolved CT angiography and catheter angiography can help identify underlying AVMs, aneurysms, cavernomas and vasculitides. MRI is more sensitive for the detection of subacute and chronic haemorrhage and identification of underlying mass lesions.

Persistent hypoglossal artery aneurysm: Case report and qualitative systematic review.

A persistent hypoglossal artery was first described in 1889 and is one of the more common anatomical variations arising from aberration in normal development. Endovascular coiling has been recognised as a robust treatment for acutely ruptured intracranial arterial aneurysms, although specific data regarding an aneurysm arising from a persistent hypoglossal artery is lacking due to the low incidence. Here we report both the oldest patient reported to be treated with a persistent hypoglossal artery-associated aneurysm and also explicitly report endovascular treatment of a persistent hypoglossal artery aneurysm arising at the posterior inferior cerebellar artery origin. Qualitative systematic review of the available medical literature demonstrates limited evidence regarding treatment of persistent hypoglossal artery-associated aneurysms with the majority being carried out via open surgery. Ruptured posterior inferior cerebellar artery aneurysm arising from a persistent hypoglossal artery can be successfully and safely treated by endovascular therapy via the persistent hypoglossal artery. Randomised study of this situation is unlikely to be feasible; however, qualitative review of the literature reveals six such aneurysms that have been treated surgically, and this case appears to be the first via an endovascular means.

Vascular B1 kinin receptors in patients with congestive heart failure.

Animal models suggest a vasomotor role for the B1 kinin receptor in cardiovascular disease states. In patients with heart failure treated with angiotensin-converting enzyme inhibition (ACEi), or combined B1/B2 receptor antagonism, but not B2 receptor antagonism alone, causes vasoconstriction. However, B1 agonism has no effect on vasomotor or fibrinolytic function. Findings from transgenic animals lacking the B2 receptor suggest that these conflicting data may be explained by cross-talk between B1 and B2 receptors. We hypothesized that B1 stimulation causes vasodilatation and tissue plasminogen activator release in the human forearm when B2 receptor signaling is inhibited. Forearm blood flow was measured in 16 patients with heart failure receiving ACEi. In double-blinded crossover studies, intrabrachial Lys-[Leu8]-des-Arg9-bradykinin (B1 antagonist), lys-des-Arg9-bradykinin (B1 agonist), bradykinin (B2 agonist), and sodium nitroprusside (endothelium-independent vasodilator) were infused alone or with HOE-140 (B2 antagonist). HOE-140 did not affect basal vascular tone or t-PA release, but it abolished bradykinin-induced vasodilatation and t-PA release (P < 0.0001). Blood flow and t-PA release were unaffected by B1 agonism or antagonism in the presence and absence HOE-140. Our findings do not support a role for crosstalk between the B1 and B2 kinin receptors in the human peripheral circulation.

Ten-year experience of retrievable inferior vena cava filters in a tertiary referral center.

PURPOSE: A significant proportion of patients undergoing surgery have an increased incidence of acute pulmonary embolus (PE). We analyzed all patients who had a retrievable inferior vena cava (IVC) filter placed preoperatively for PE prophylaxis and investigated the long-term outcomes of the patients who did not have their filter removed. METHODS: Patients who underwent retrievable IVC filter insertion and attempted removal were identified from the radiology information systems database in a large tertiary referral university teaching hospital. Results of all clinical investigations (including computed tomography, magnetic resonance imaging, ultrasonography, and plain radiography) while the IVC filters were in situ were reviewed. RESULTS: In total, 393 retrievable IVC filters were inserted, 254 with the indication of preoperative thromboembolic prophylaxis. Recurrent PE was reported in five patients (1.9%) despite the IVC filter. Of the 254 retrievable filters inserted prior to surgery, an attempt at retrieval was made in 168 filters (66.1%). Successful retrieval at the first attempt occurred in 143 cases (85.1%), while 25 cases failed or were aborted (14.9%). No attempt at retrieval was made in 86 (33.9%) patients and a significant proportion of these patients had undergone cancer surgery (P < 0.0107). In those patients where there was no attempt at retrieval, there was an association between cancer surgery and a shorter absolute survival time (P < 0.0001). CONCLUSION: The majority of attempted filter retrievals were successful, and a proportion of nonretrieved IVC filters are accounted for in patients who underwent cancer surgery and ultimately died with the filter in situ. A departmental protocol is recommended to ensure the filter is removed where appropriate and possible.

Cervical cord decompression following embolisation of a giant cervical vertebro-vertebral arteriovenous fistula.

Arteriovenous fistulation between the vertebral arteries to extradural (epidural) veins, termed vertebro-vertebral arteriovenous fistulae, are uncommon diagnoses without established diagnostic algorithms or treatment options. Minimal evidence exists describing the management of this pathology. Endovascular treatment was performed under general anaesthesia by coil occlusion of the vertebral artery from the point of the fistula to the mid-vertebral artery. Repeat magnetic resonance angiographic imaging one week following the procedure confirmed an 80% reduction in the size of the epidural vein and decompression of the cervical spinal cord. At four-week follow-up there was significant qualitative improvement in the myelopathic symptoms including walking distance and pain. Normal physiological filling of the collapsed extradural vein was observed on follow-up digital subtraction angiography at five months. Catheter angiography by an experienced interventional neuro-radiologist is critical in defining the anatomy and providing minimally invasive treatment.

B1 kinin receptor does not contribute to vascular tone or tissue plasminogen activator release in the peripheral circulation of patients with heart failure.

OBJECTIVE: Vascular expression of the B1 kinin receptor is markedly upregulated with left ventricular dysfunction and angiotensin-converting enzyme (ACE) inhibition, but its function remains unclear. Inhibitors of ACE potentiate bradykinin-mediated B2 receptor-dependent vasodilatation and tissue plasminogen activator (tissue-type plasminogen activator [t-PA]) release. We investigated the contribution of the B1 receptor to the maintenance of vascular tone and t-PA release in patients with heart failure. METHODS AND RESULTS: Eleven patients were treated with enalapril (10 mg twice daily) or losartan (50 mg twice daily) in a randomized double-blind crossover trial. During week 6 of each treatment, patients received an intrabrachial infusion of Lys-des-Arg9-bradykinin (B1 agonist; 1 to 10 nmol/min), bradykinin (30 to 300 pmol/min), Lys-[Leu8]-des-Arg9-bradykinin (B1 antagonist; 1 to 10 nmol/min), and norepinephrine (60 to 540 pmol/min). Blood flow and t-PA release were measured using venous occlusion plethysmography and blood sampling. Bradykinin (P<0.001 for all), but not Lys-des-Arg9-bradykinin, caused vasodilatation and t-PA antigen and activity release. Norepinephrine (P<0.001), but not Lys-[Leu8]-des-Arg9-bradykinin, caused vasoconstriction. Compared with losartan, enalapril augmented bradykinin-mediated vasodilatation (P<0.05) and t-PA release (P<0.01 for all) but had no effect on B(1) receptor-mediated responses. CONCLUSIONS: The B1 kinin receptor does not have a major vasomotor or fibrinolytic role in patients with heart failure. Augmentation of kinin-mediated vasodilatation and t-PA release by ACE inhibition is restricted to the B2 receptor.

Dispelling the nice or naughty myth: retrospective observational study of Santa Claus.

OBJECTIVE:  To determine which factors influence whether Santa Claus will visit children in hospital on Christmas Day. DESIGN:  Retrospective observational study. SETTING:  Paediatric wards in England, Northern Ireland, Scotland, and Wales. PARTICIPANTS:  186 members of staff who worked on the paediatric wards (n=186) during Christmas 2015. MAIN OUTCOME MEASURES:  Presence or absence of Santa Claus on the paediatric ward during Christmas 2015. This was correlated with rates of absenteeism from primary school, conviction rates in young people (aged 10-17 years), distance from hospital to North Pole (closest city or town to the hospital in kilometres, as the reindeer flies), and contextual socioeconomic deprivation (index of multiple deprivation). RESULTS:  Santa Claus visited most of the paediatric wards in all four countries: 89% in England, 100% in Northern Ireland, 93% in Scotland, and 92% in Wales. The odds of him not visiting, however, were significantly higher for paediatric wards in areas of higher socioeconomic deprivation in England (odds ratio 1.31 (95% confidence interval 1.04 to 1.71) in England, 1.23 (1.00 to 1.54) in the UK). In contrast, there was no correlation with school absenteeism, conviction rates, or distance to the North Pole. CONCLUSION:  The results of this study dispel the traditional belief that Santa Claus rewards children based on how nice or naughty they have been in the previous year. Santa Claus is less likely to visit children in hospitals in the most deprived areas. Potential solutions include a review of Santa's contract or employment of local Santas in poorly represented regions.

Heat shock protein 90 inhibition abrogates TLR4-mediated NF-κB activity and reduces renal ischemia-reperfusion injury.

Renal ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury. Toll-like receptor 4 (TLR4) mediates sterile inflammation following renal IRI. Heat shock protein 90 (Hsp90) inhibition is a potential strategy to reduce IRI, and AT13387 is a novel Hsp90 inhibitor with low toxicity. This study assessed if pre-treatment with AT13387 could reduce renal IRI and established if the mechanism of protection involved a reduction in inflammatory signalling. Mice were pre-treated with AT13387 prior to renal IRI. 24 h later, renal function was determined by serum creatinine, kidney damage by tubular necrosis score, renal TLR4 expression by PCR and inflammation by cytokine array. In vitro, human embryonic kidney cells were co-transfected to express TLR4 and a secreted alkaline phosphatase NF-κB reporter. Cells were pre-treated with AT13387 and exposed to endotoxin-free hyaluronan to stimulate sterile TLR4-specific NF-κB inflammatory activation. Following renal IRI, AT13387 significantly reduced serum creatinine, tubular necrosis, TLR4 expression and NF-κB-dependent chemokines. In vitro, AT13387-treatment resulted in breakdown of IκB kinase, which abolished TLR4-mediated NF-κB activation by hyaluronan. AT13387 is a new agent with translational potential that reduces renal IRI. The mechanism of protection may involve breakdown of IκB kinase and repression of TLR4-mediated NF-κB inflammatory activity.