Monitoring neurointerventional radiation doses using dose-tracking software: implications for the establishment of local diagnostic reference levels.

OBJECTIVES: There is potential for high radiation exposure during neurointerventional procedures. Increasing regulatory requirements mandate dose monitoring of patients and staff, and justification of high levels of radiation exposure. This paper demonstrates the potential to use radiation dose-tracking software to establish local diagnostic reference levels. METHODS: Consecutive neurointerventional procedures, performed in a single institution within a one-year period, were retrospectively studied. Dose area product (DAP) data were collected using dose-tracking software and clinical data obtained from a prospectively generated patient treatment database. RESULTS: Two hundred and sixty-four procedures met the selection criteria. Median DAP was 100 Gy.cm2 for aneurysm coiling procedures, 259 Gy.cm2 for arteriovenous malformation (AVM) embolisation procedures, 87 Gy.cm2 for stroke thrombolysis/thrombectomy, and 74 Gy.cm2 for four-vessel angiography. One hundred and nine aneurysm coiling procedures were further studied. Six significant variables were assessed using stepwise regression analysis to determine effect on DAP. Aneurysm location (anterior vs posterior circulation) had the single biggest effect (p = 0.004). CONCLUSIONS: This paper confirms variable radiation exposures during neurointerventional procedures. The 75th percentile (used to define diagnostic reference levels) of DAP measurements represents a reasonable guidance metric for monitoring purposes. Results indicate that aneurysm location has the greatest impact on dose during coiling procedures and that anterior and posterior circulation coiling procedures should have separate diagnostic reference levels. KEY POINTS: • Dose-tracking software is useful for monitoring patient radiation dose during neurointerventional procedures • This paper provides a template for methodology applicable to any interventional suite • Local diagnostic reference levels were defined by using the 75th percentile of DAP as per International Commission on Radiological Protection recommendations • Aneurysm location is the biggest determinant of radiation dose during coiling procedures. • Anterior and posterior circulation coiling procedures should have separate diagnostic reference levels.

Subarachnoid and parenchymal haemorrhages as a complication of severe diabetic ketoacidosis in a preadolescent with new onset type 1 diabetes.

Diabetic ketoacidosis (DKA) is one of the most common causes of morbidity and mortality in new onset type 1 diabetes mellitus (T1DM). Children have a higher rate of neurological complications from DKA when compared to adults. The differential for sudden focal neurological deterioration in the setting of DKA is cerebral oedema followed by ischaemic and haemorrhagic stroke. Spontaneous intracranial haemorrhages can present with non-specific features frequently, for example, impaired consciousness, even when biochemical parameters are improving in the setting of DKA. We report the case of a girl with new onset T1D who presented in severe DKA and subsequently developed intracerebral parenchymal and subarachnoid haemorrhages. Our patient is unique in that no focal neurological or neuropsychological deficits have been found at 1-year follow up, compared to the literature which suggests poor outcomes. Our case contrasts with these previous cases as none of the other case reports demonstrated subarachnoid haemorrhages with survival.

Low-Dose Carotid Computed Tomography Angiography Using Pure Iterative Reconstruction.

UNLABELLED: The aim of this study was to assess if a low-dose carotid computed tomography angiography (CTA) performed with pure iterative reconstruction (IR) is comparable to a conventional dose CTA protocol. METHODS: Twenty patients were included. Radiation dose was divided into a low-dose acquisition reconstructed with pure IR and a conventional dose acquisition reconstructed with 40% hybrid IR. Dose, image noise, contrast resolution, spatial resolution, and carotid artery stenosis were measured. RESULTS: Mean effective dose was significantly lower for low-dose than conventional dose studies (1.84 versus 3.71 mSv; P < 0.001). Subjective image noise, contrast resolution, and spatial resolution were significantly higher for the low-dose studies. There was excellent agreement for stenosis grading accuracy between low- and conventional dose studies (Cohen κ = 0.806). CONCLUSIONS: A low-dose carotid CTA protocol reconstructed with pure IR is comparable to a conventional dose CTA protocol in terms of image quality and diagnostic accuracy while enabling a dose reduction of 49.6%.

Auditory hallucination in basilar occlusion: I heard it was the basilar.

Acute basilar artery occlusion is a neurological emergency. Unlike anterior circulation stroke presenting with hemiparesis, the symptoms of basilar artery occlusion are challenging to recognise in the emergency setting. Basilar artery occlusion can rarely lead to ischaemia of the auditory pathways, resulting in bizarre, positive auditory hallucinations. Here, we report two cases of basilar artery occlusion presenting with positive auditory phenomena; in both cases the auditory phenomenon resolved upon arterial recanalisation. We discuss the phenomenology of this unusual and distinctive neurological symptom. Acute auditory hallucinosis in the setting of sudden vomiting, dizziness, visual disturbance or other posterior circulation symptoms should prompt emergency imaging of the basilar artery, to avoid a potentially devastating posterior circulation stroke.

A single centre retrospective analysis of short- and medium-term outcomes using the Woven EndoBridge (WEB) device and identification of the device-to-aneurysm volume ratio as a potential predictor of aneurysm occlusion status.

BACKGROUND: The Woven EndoBridge (WEB) is a potential treatment option in patients with wide-necked bifurcation aneurysms (WNBAs). We analysed our WEB device outcomes (occlusion rates and complications) and studied factors that may predict aneurysm occlusion status at short- and medium-term follow-up. METHODS: 74 patients with ruptured and unruptured aneurysms underwent treatment with the WEB device over a 5-year period. Simple hypothesis tests assessed differences between treated ruptured and unruptured aneurysms. Univariable binary logistic regression was used to assess the effect of age, gender, and aneurysm location on the likelihood of adequate occlusion at six months. Aneurysm dimentions including device-to-aneurysm volume (DAV) ratios were compared between adequately and inadequately occluded aneurysms. RESULTS: The mean age at the time of the procedure was 58.2 years (SD 12.2; range 34-88) and the male to female ratio was 1:2.7. Middle cerebral artery (MCA) was the most commonly treated aneurysm. There was no significant difference in occlusion rates between ruptured and unruptured aneurysms. The six- and 18-month angiographic follow-up data was available for 61 and 32 patients respectively with adequate occlusion rates of 78.7% (48/61) and 78.1% (25/32). Procedure-related complications occurred in 6 patients (8.1%). Baseline DAV ratio was found to be significantly higher in aneurysms that were adequately occluded at both short- (p-value 0.015) and medium-term (p-value 0.047) follow-up. CONCLUSIONS: WEB devices are a safe and effective endovascular treatment option for WNBAs. WEB device selection incorporating the peri-procedural DAV ratio may help improve the accuracy of device sizing thereby improving the successful occlusion rate.

Superior cerebellar aneurysm causing subarachnoid haemorrhage in a 17-year-old with alagille syndrome.

Alagille syndrome is a rare autosomal dominant condition characterised by mutation in Jagged1 gene. Intracranial aneurysms may be seen in this condition and may present as subarachnoid hemorrhage. We describe the first case of superior cerebellar aneurysm rupture causing WFNS grade 1 subarachnoid haemorrhage in a 17-year-old girl. The clinical condition and management of this rare occurrence is discussed with a review of literature.

Clinical audit comparing radiation dose metrics between WEB and coil embolisation in the treatment of intracranial aneurysms.

INTRODUCTION: Intrasaccular flow disruption is a new and effective endovascular treatment for intracranial aneurysms. While endovascular treatment is a minimally invasive procedure, it does carry a radiation risk. As radiation dose should be kept as low as reasonably achievable (ALARA), the main objective of this study was to analyse KAP (kerma area product), fluoroscopy and procedure time during the treatment of aneurysms treated with coiling and the Woven-EndoBridge (WEB) device. A secondary objective was to look at the reference air kerma (RAK) to determine if the patient receives a dose that could cause tissue effects. METHODS: KAP, fluoroscopy and procedure time were retrospectively analysed in patients who had an aneurysm treatment. Aneurysms with diameters of 4-11mm, over a four-year period, in the anterior and posterior circulation of the brain were analysed in this study. Patients were treated by coiling or WEB. RAK were summed together in the working projection to give an estimated entrance surface dose (ESD) in cases with the highest KAP. RESULTS: A total of 47 aneurysms treated with WEB and 104 aneurysms treated with coiling techniques met the inclusion criteria. The average KAP was 6884.1 ± 2774.4µGym2 with coiling techniques and 5658.7 ± 1602.5µGym2 with WEB (p=0.006; CI =363-2086µGym2). This demonstrates an 18% reduction with WEB. Mean fluoroscopy time for coiling was 63.5 ± 42.6minutes and 33.8 ± 28.8minutes for WEB (p=<0.001; CI=16-43minutes). Fluoroscopy time was reduced by nearly 50% with WEB. On average, there was a 27-minute reduction of procedure time when using WEB compared to coiling. The RAK determined for the working projections did not exceed the 2Gy threshold for tissue effects. CONCLUSION: Treatment of aneurysms using the WEB shows a reduction in KAP, fluoroscopy, and procedure time. This study further demonstrates the benefits of intrasaccular flow disruption for treatment of intracranial aneurysms.

Case report: BRAF-inhibitor therapy in BRAF-mutated primary CNS tumours including one case of BRAF-mutated Rosai-Dorfman disease.

BRAF V600E oncogene mutations have been reported in multiple central nervous system (CNS) tumor types, and emerging evidence supports the use of targeted therapy in BRAF-mutated gliomas. BRAF oncogene mutations have been recently identified in Rosai-Dorfman disease (RDD)-a rare non-Langerhans cell histiocytosis. This series describes three patients from two neurosurgical centers in Ireland with BRAF V600E-mutated CNS tumors. The study participants include a 19-year-old male patient with ganglioglioma with anaplastic features, a 21-year-old male patient with CNS involvement of RDD, and a 28-year-old female patient with ganglioglioma with anaplastic features. Two patients received radiation with concurrent temozolomide before BRAF-targeted therapy. This case series describes clinical and radiological responses to BRAF-targeted therapy in BRAF V600E-mutated gliomas across multiple tumor grades and is only the second published report of response to targeted therapy in BRAF-mutated RDD. The durability of disease control with BRAF-targeted therapy was generally superior to that achieved with chemoradiation; one patient has experienced ongoing disease control for 5 years. The reported case of treatment response in BRAF-mutated RDD supports the strategy of genotyping and utilization of targeted therapy in this rare disease. The optimal sequencing of BRAF-targeted therapy in BRAF-mutated gliomas/glioneuronal tumors remains unclear, and further prospective studies are required to guide the use of genome-matched therapy in this patient population.

Development and implementation of an ultralow-dose CT protocol for the assessment of cerebrospinal shunts in adult hydrocephalus.

BACKGROUND: Cerebrospinal fluid shunts in the treatment of hydrocephalus, although associated with clinical benefit, have a high failure rate with repeat computed tomography (CT) imaging resulting in a substantial cumulative radiation dose. Therefore, we sought to develop a whole-body ultralow-dose (ULD) CT protocol for the investigation of shunt malfunction and compare it with the reference standard, plain radiographic shunt series (PRSS). METHODS: Following ethical approval, using an anthropomorphic phantom and a human cadaveric ventriculoperitoneal shunt model, a whole-body ULD-CT protocol incorporating two iterative reconstruction (IR) algorithms, pure IR and hybrid IR, including 60% filtered back projection and 40% IR was evaluated in 18 adult patients post new shunt implantation or where shunt malfunction was suspected. Effective dose (ED) and image quality were analysed. RESULTS: ULD-CT permitted a 36% radiation dose reduction (median ED 0.16 mSv, range 0.07-0.17, versus 0.25 mSv (0.06-1.69 mSv) for PRSS (p = 0.002). Shunt visualisation in the thoracoabdominal cavities was improved with ULD-CT with pure IR (p = 0.004 and p = 0.031, respectively) and, in contrast to PRSS, permitted visualisation of the entire shunt course (p < 0.001), the distal shunt entry point and location of the shunt tip in all cases. For shunt complications, ULD-CT had a perfect specificity. False positives (3/22, 13.6%) were observed with PRSS. CONCLUSIONS: At a significantly reduced radiation dose, whole body ULD-CT with pure IR demonstrated diagnostic superiority over PRSS in the evaluation of cerebrospinal fluid shunt malfunction.

Drip and ship versus direct to endovascular thrombectomy: The impact of treatment times on transport decision-making.

INTRODUCTION: In ischaemic stroke care, fast reperfusion is essential for disability free survival. It is unknown if bypassing thrombolysis centres in favour of endovascular thrombectomy (mothership) outweighs transport to the nearest thrombolysis centre for alteplase and then transfer for endovascular thrombectomy (drip-and-ship). We use conditional probability modelling to determine the impact of treatment times on transport decision-making for acute ischaemic stroke. MATERIALS AND METHODS: Probability of good outcome was modelled using a previously published framework, data from the Irish National Stroke Register, and an endovascular thrombectomy registry at a tertiary referral centre in Ireland. Ireland was divided into 139 regions, transport times between each region and hospital were estimated using Google's Distance Matrix Application Program Interface. Results were mapped using ArcGIS 10.3. RESULTS: Using current treatment times, drip-and-ship rarely predicts best outcomes. However, if door to needle times are reduced to 30 min, drip-and-ship becomes more favourable; even more so if turnaround time (time from thrombolysis to departure for the endovascular thrombectomy centre) is also reduced. Reducing door to groin puncture times predicts better outcomes with the mothership model. DISCUSSION: This is the first case study modelling pre-hospital transport for ischaemic stroke utilising real treatment times in a defined geographic area. A moderate improvement in treatment times results in significant predicted changes to the optimisation of a national acute stroke patient transport strategy. CONCLUSIONS: Modelling patient transport for system-level planning is sensitive to treatment times at both thrombolysis and thrombectomy centres and has important implications for the future planning of thrombectomy services.

CT of the head for acute stroke: Diagnostic performance of a tablet computer prior to intravenous thrombolysis.

INTRODUCTION: The authors propose that tablet computers could benefit patients with acute stroke in the remote care setting, where time to and accuracy of CT interpretation greatly influences patient outcome. METHODS: One hundred and fifty consecutive patients who presented to the Emergency Department of a tertiary referral neurosciences centre within a time window suitable for intravenous thrombolytic therapy were included. Images were wirelessly transmitted to a tablet computer (iPad 3rd Generation, model = A1430, Apple, Cupertino, CA) and were reviewed by radiologists with three levels of experience for signs of intracranial haemorrhage, large vessel occlusion and parenchymal infarction. Reference standard interpretation was performed by two neuroradiologists using a diagnostic monochrome display. RESULTS: Consensus neuroradiologist review on the tablet display found and correctly classified all of the 23 cases of intracranial haemorrhage including 21 cases of parenchymal haematoma, two cases of petechial haemorrhage and one patient with an acute subdural haematoma. Less experienced readers missed cases of petechial and subdural haematomas. There was excellent agreement between the tablet and diagnostic monochrome display in cases with no infarct or extensive parenchymal infarction. CONCLUSIONS: Tablet computers can be used to facilitate rapid preliminary CT interpretation in patients with acute stroke in the remote setting.

Brain dead or not? CT angiogram yielding false-negative result on brain death confirmation.

We describe a case of severe traumatic brain injury with multiple facial and skull fractures where CT angiogram (CTA) failed to yield a definite result of brain death as an ancillary test. A 28-year-old man was admitted following a road traffic accident with a Glasgow Coma Score (GCS) of 3/15 and fixed pupils. CT brain revealed uncal herniation and diffuse cerebral oedema with associated multiple facial and skull fractures. 72 h later, his clinical condition remained the same with high intracranial pressure refractory to medical management. Clinical confirmation on brain death was not feasible owing to facial injuries. A CTA, performed to determine brain perfusion, yielded a 'false-negative' result. Skull fractures have possibly led to venous prominence in the cortical and deep venous drainage system. This point needs to be borne in mind while considering CTA as an ancillary test to confirm brain death.

Solitaire FR stent as an adjunctive tool for pipeline stent deployment in the treatment of giant intracranial aneurysms.

BACKGROUND AND IMPORTANCE: The use of flow-diverting stents has gained acceptance during the past few years for the treatment of numerous intracranial aneurysms, especially large or giant ones. However, successful catheterization of the distal parent artery in giant intracranial aneurysms with a microcatheter can be extremely challenging. Forming a microcatheter loop in the aneurysm sac can aid distal catheterization. CLINICAL PRESENTATION: We report the use of a Solitaire FR stent as an adjunctive tool in the successful treatment of 2 giant intracranial unruptured aneurysms with a Pipeline Embolization Device. After having formed a loop inside the aneurysm sac, the microcatheter was anchored distally by a Solitaire FR stent. With the Solitaire FR device opened, the loop in the giant aneurysm sac was completely reduced without loss of the microcatheter position in the distal parent artery. A Pipeline Embolization Device could be delivered in both cases without any difficulty. There were no complications. CONCLUSION: The technique described results in ideal microcatheter alignment with a secure distal position before deployment of a flow-diverting stent.

Bronchogenic adenocarcinoma presenting as a synchronous solitary lytic skull lesion with ischaemic stroke--case report and literature review.

The authors describe a rare case of metastatic bronchogenic adenocarcinoma in a 55-year-old man presenting with concomittant solitary lytic skull lesion and ischaemic stroke. Metastatic bronchogenic carcinoma is known to present as lytic skull lesions. Primary brain tumours are also known to cause ischaemic brain injury. An underlying stroke risk may be exagerated by cranial tumour surgery. Patients with brain tumours are well known to be predisposed to an increased risk of developing thromboembolic disease. It is unusual to see metastatic bronchogenic adenocarcinoma presenting as ischaemic stroke with a background of concomittant cerebral metastasis. The aetio-pathogenesis of this rare occurrence is discussed with a review of literature.

Percutaneous thermal ablation in the head and neck: current role and future applications.

Patients with recurrent head and neck cancer have poor quality of life and suffer dismally from debilitating symptoms. Ablative techniques offer patients an alternative, minimally invasive treatment option. As a palliative treatment, they improve quality of life with decreased pain, improved function and appearance. In addition, there is a reduction in tumor bulk and analgesia requirements. Advantages include a reduction in procedural cost, avoidance of complex repetitive surgeries, and an ability to visualize the treated area at the time of the procedure. Ablation therapies are an evolving and exciting treatment option in the head and neck, but a consensus on appropriate indications is currently unclear.

Neurointervention for the peripheral radiologist: tips and tricks.

Interventional neuroradiology is a high-risk, high-yield field with small margins for catastrophic errors. A wider range of complex vascular disorders of the brain, spine, head, and neck are now treatable with new endovascular technology. This article describes new tools and techniques in this ever-expanding field.

Limitations of magnetic resonance imaging and magnetic resonance angiography in the diagnosis of intracranial aneurysms.

OBJECTIVE: Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) are being used with increasing frequency for the diagnosis of intracranial aneurysms. Although the literature suggests that MRI and MRA are accurate, we have observed that both are associated with a high likelihood of false-positive results in the diagnosis of aneurysms. We prospectively evaluated and compared the accuracy of MRI/MRA versus digital subtraction angiography (DSA) for the diagnosis of intracranial aneurysms. METHODS: Over the course of 2 years, 133 patients diagnosed with one or more unruptured intracranial aneurysms by MRI/MRA were prospectively evaluated in an outpatient setting. The patients were advised to undergo cerebral four-vessel DSA, and the results from DSA were compared with MRI/MRA findings. RESULTS: In 59% of cases, the DSA and MRI/MRA findings were markedly different. Specifically, in 38% of MRI/MRA-positive cases, DSA findings were completely normal, showing no aneurysms. In an additional 21% of cases, although DSA confirmed the presence of an aneurysm, it differed substantially from MRI/MRA findings in terms of aneurysm location, number of aneurysms, or aneurysm type. In general, the false-positive aneurysms by MRI/MRA were smaller than 5 mm and were most commonly identified in the anterior communicating artery region. CONCLUSION: MRI/MRA studies are often inaccurate in the diagnosis of intracranial aneurysms and should not be used as the sole diagnostic studies for intracranial aneurysms. Other radiographic modalities should be further investigated as alternatives to MRI/MRA for the diagnosis of intracranial aneurysms.