Abstracts – ANZSNR ASM 2024

Introduction: Endovascular clot retrieval (ECR) exists as the gold standard for the management of acute ischaemic stroke secondary to large vessel occlusion. There is a direct correlation between reduced time to reperfusion and improved patient outcomes. Our study aimed to optimise processes and reduce the time from patient's arrival at hospital to vascular puncture for mechanical thrombectomy (DTG time) through simulation-based staff training. Methods: This single-centre prospective study involved simulation-based training completed during three months from March to May 2023. Simulations were conducted involving multidisciplinary staff where an ECR patient's hyperacute journey through the hospital was simulated followed by formal debriefing and highlighting areas for improvement. Patients at our hospital who underwent ECR in the six-month period pre- and post-simulation training were included in our observation. We recorded patient characteristics and timestamps including time of arrival to hospital, CT imaging, arrival to angiography suite, intubation and groin puncture. The primary outcome measured was the DTG time. For statistical analysis, a paired t-test was used to compare values. Results: In the period prior to the simulation training, our hospital recorded 19 direct to hospital presentations for patients requiring ECR, where we recorded a mean DTG time of 132.38 min. Post the simulation training, we recorded 26 direct to hospital presentations, with a mean DTG time of 104.52 min (a reduction of 27.86 minutes, p = 0.02). This time reduction was most significant from time between CT imaging to arrival at the angiogram suite. There was no significant difference between time from arrival at hospital to CT imaging, or time spent on intubation. Our study did not find any statistically significant difference in DTG time for patients who were inter-hospital transfer presentations. Conclusions: We validated simulation-based training as an effective intervention for reducing time to reperfusion for patients undergoing ECR. Implementation of regular training for staff can improve patient outcomes. Introduction: Each year, traumatic head injuries account for nearly half a million ED presentations in Australia, with a significant proportion requiring no further treatment post-observation. However, neurosurgical intervention is necessary in a critical subset of these patients, underscoring the importance of timely and accurate detection of intracranial pathology through CT head scans. Despite the availability of joint RANCZR and ACEM recommendations for appropriate diagnostic imaging in blunt head injury, adherence remains suboptimal. This retrospective audit examines compliance with and the effectiveness of these guidelines in a tertiary emergency service. Methods: All CT head requests from 1 Jan 2023 to 31 March 2023 in a tertiary and urban ED were obtained (n = 1,322). From this, adults (≥16 years) presenting with head injury secondary to blunt trauma in the preceding 24 hours (n = 539) were selected for analysis. Data on clinical variables (e.g., age, gender, GCS, and mechanism of injury) and outcomes were collected via medical record and radiology data base review. Following established guidelines, patients were classified into three categories: those at high risk requiring CT, those with minimal head injuries not needing further workup and those with minor head injuries who underwent further risk stratification based on a retrospective application of the Canadian CT head rule. Results: Of the 539 included studies, we identified 138 patients with high-risk head injuries, 296 with minor injuries and 105 with minimal injuries. The application of the Canadian CT head rules to those categorised as minor injuries placed 180 in the high-risk category, 26 as medium risk and 90 as low risk. Notably, among the nine scans that revealed intracranial haemorrhage, none were from patients initially considered a minimal head injury or classified as low-risk postapplication of the Canadian CT head rule. This analysis suggests adherence to clinical guidelines could have avoided 195 unnecessary scans without compromising patient outcomes. Conclusion: This study underscores the efficacy of the joint RANCZR and ACEM guidelines for diagnostic imaging in blunt head trauma yet reveals a gap in adherence. Enhancing compliance through education or integrating these recommendations into electronic medical systems may improve utilisation. A follow-up audit after implementing these measures is expected to show positive outcomes. Guideline used (joint RANCZR and ACEM recommendation) Osmotic demyelination syndrome (ODS) is an encephalopathy that commonly, but not always, occurs after rapid correction of serum sodium in a patient with hyponatremia. MRI remains the imaging standard of diagnosis, and this study aimed primarily to describe the MR features of ODS in cases managed in a tertiary training institution. Secondarily, this study also aimed to describe the associated clinical features. A total of 22,200 indexed MRI reports between 01 January 2014 and 31 December 2023 from a single tertiary training institution/end-referral centre were searched, and 14 clinically diagnosed cases of osmotic demyelination syndrome with complete MR images and laboratory records were identified. The study was conducted with the approval of the institutional research ethics board. Osmotic demyelination syndrome consistently presents with T1W-hypointense, T2W−/T2-FLAIR- hyperintense signals with restricted diffusion with an average absolute diffusion coefficient of 456.82 ± 65.04 × 10–6 mm2/s. No enhancement is seen in any of the cases and no magnetic susceptibility artefacts that may suggest haemorrhage are noted. These scans were obtained at a median of 3 days from onset of symptoms, with altered mental status being the most common presentation (86%). Combined pontine and extrapontine involvement is seen in majority of cases (64%); moreover, the morphology of the pontine lesions can be grouped into one of four characteristic appearances – linear streaks (17%), central triangular patches (17%), ventral tract-sparing patterns (‘piglet sign’ or ‘trident sign’) (58%) and diffuse pontine patches (8%) – likely correlating with varying degrees of involvement of the pontine white matter tracts. Of these, the ‘trident’ appearance is the most common (50%), further establishing the utility of the sign in diagnosis. Of the extrapontine sites, the lentiform nucleus (43%) and thalamus (36%) were most commonly affected. Other sites involved include the caudate nucleus, midbrain, cerebellum, external capsule, internal capsule, corona radiata, corpus callosum, and hippocampus, in descending order of frequency. The clinical data gleaned also show that ODS can develop in patients receiving sodium correction of <12 mEq/L, corroborating more recent recommendations of correcting at rates slower than 8 mEq/L per day. Background: Internal carotid artery (ICA) extracranial dissection is a leading cause of ischaemic stroke in younger patients. Currently, there is no consensus on the role of endovascular therapy management of acute ischaemia caused by ICA dissection due to a paucity of evidence. Flow diverting stents (FDS) may be a reasonable treatment alternative to standard carotid stents when they are unsuitable due to vascular tortuosity in high cervical and skull base segments. Objectives: To report a case series of patients treated with FDS for cervical dissections presenting with acute ischaemic stroke where traditional stents were unsuitable, with a focus on reviewing perioperative antithrombotic therapy. Methods: We retrospectively reviewed all patients presenting to a tertiary academic hospital from 2017 to 2023 with acute ischaemic stroke secondary to extracranial carotid artery dissection treated with FDS. Patient clinical characteristics, presentation, procedural and follow-up imaging, as well as clinical outcomes were analysed. Results: We treated 21 patients with a total of 22 dissections with FDS of whom 12 patients were male and 9 were female. All patients had a prestroke mRS of 0. Four dissections were traumatic, one was iatrogenic following elective intracranial aneurysm treatment, two were secondary to vasculitis and the remaining 14 were spontaneous. Seven patients required ICA thrombectomy, and 10 required middle cerebral artery (MCA) thrombectomy. All patients presented with clinical or radiological evidence of acute cerebral ischaemia. Seventeen of 21 patients had large vessel occlusion (LVO), all of which achieved recanalisation of mTICI 2b or better. Three patients suffered stent occlusion within 48 hours. Five patients had haemorrhagic complications, of whom two were symptomatic. Four patients had in-stent stenosis on follow up imaging. 90% (18 of 21) patients achieved mRS score of 0–1 at 3 months of follow-up. Conclusions: Our initial experience with FDS in acute ischaemic stroke shows that FDS is a technique that potentially provides a safe alternative when traditional stents are not suitable. Larger case series are needed to better establish optimal patient selection, and the ideal periprocedural antiplatelet therapy. Background: Punctate white matter injury (PWMI) is frequently observed in infants as discrete localised areas of high signal intensity on T1- and low-signal intensity on T2-weighted MRI. However, their aetiology remains unclear. Our aim was to delineate the anatomical distribution of PWMI on MRI and quantitatively assess brain lesion volumes in three groups – preterm infants, infants with congenital heart disease (CHD) and healthy term controls. Methods: The location and volume of PWMI was assessed on MRI in 109 infants scanned at 37–43 weeks’ gestation. Punctate lesions were manually segmented, and probabilistic lesion maps were developed for each group of infants from a neonatal specific brain template. Results: Preterm infants had greater whole-brain PWMI volume (p < 0.001) and greater lesion load in the corticospinal tracts (p = 0.003) compared with healthy term controls. Punctate lesion volumes in preterm infants were also higher in the temporal lobes than in term controls (p < 0.001) and infants with CHD (p = 0.016). Lesion distribution among infants with CHD was more similar to that of term controls. Infants with CHD had greater whole-brain PWMI volume (p = 0.012) and relative PWMI volumes (p = 0.009) compared to term controls. Conclusion: Differences in PWMI distribution between preterm infants, infants with CHD and healthy term controls is in line with the regional maturational stage of oligodendrocytes and white matter development. Our findings support the role of vulnerable premyelinating oligodendrocytes as a key component in the pathophysiology of punctate lesion formation. Background: Dural venous sinus stenting (VSS) is an effective treatment for select patients with idiopathic intracranial hypertension (IIH); however, over time, these patients can develop a new juxta-stent stenosis with a pressure gradient resulting in a recurrence of intracranial hypertension and symptoms. Re-stenting may be performed although there is limited evidence base to guide management. In this study, we evaluated the efficacy and long-term outcomes of repeat stenting in patients treated at one Australian institute. Methods: A retrospective review of a database of 274 patients treated at our institution for IIH with VSS over a span of 16 years (from 2006 to 2023) identified 17 patients who underwent re-stenting for treatment failure. Clinical features, outcomes and venographic data were collated for each patient from their first stent to the second with clinical outcome data obtained from each patient's latest available follow up after their second stent. Results: The mean time to repeat stenting was 4 years and 4 months with a range of 1 month to 13 years and 7 months. At the time of first stent treatment failure, there were 15 patients (88.2%) with headache, 7 (41.2%) with tinnitus and 4 (23.5%) with papilledema. Follow-up time after second stent placement ranged from 2 months to 9 years (Mean ± SD, 3.78 ± 2.93 years). At latest follow-up, 3 patients (17.6%) were asymptomatic following second stenting, 12 (70.6%) had ongoing headaches and 1 patient (5.88%) had ongoing tinnitus. Patients with persistent symptoms did not have evidence of elevated pressure or any further treatable sinus stenosis on imaging. There were three patients (17.6%) who developed recurrent elevated pressures and papilledema during follow-up, of these patients, 2 (11.8%) underwent surgical shunting and one patient (5.88%) developed further juxta-stent stenosis and received a third stent. There were no major complications in any patient. Conclusions: Repeat VSS can be an efficacious and safe treatment for IIH patients who develop new juxta-stent stenosis after initial stenting. Treatment failure requiring another intervention following re-stenting occurred in three of 17 patients (17.6%). Persistent headaches is common but is likely due to mechanisms aside from IIH. Objectives: To discuss the diagnostic and therapeutic contributions of interventional neuroradiology in the treatment of head and neck mycotic aneurysms in children. To describe different treatment options for paediatric head and neck mycotic aneurysms. To describe the patient related factors that determine the outcome of treatment. Methodology: Retrospective study reviewing clinical and radiological data of children diagnosed with mycotic aneurysms. Results: A total of eight patients over the last 8 years diagnosed with head and neck mycotic aneurysms were included. Age of the patients ranged from 3 months to 10 years. All patients underwent biplane digital subtraction angiography (DSA) in addition to CT and MRI imaging. The smallest aneurysm was 2 mm and the largest was 16 mm. Five patients underwent endovascular treatment, two underwent surgical treatment and one had a combination of endovascular and surgical treatment. Follow-up imaging was done with CT / MRI and DSA. Seven of eight patients had a favourable treatment outcome. One child with background lymphoma, on immunosuppression and with systemic fungal sepsis, succumbed due to progressive fungal encephalopathy. Conclusion: Interventional neuroradiology has a significant role in the diagnosis and treatment of head and neck mycotic aneurysms in the paediatric population. Endovascular treatment can be effective in suitable cases while valuable anatomical information can be obtained in cases planned for surgical treatment. Both liquid embolic agents such as Onyx and coils (with or without balloon assistance) can be used to successfully treat such aneurysms. Patient factors such as immunosuppression, coexisting malignancy or sepsis can potentially have an adverse effect on the outcome of the treatment. Background: When planning for an operation, a conundrum faced by neurosurgeons is that tissue samples are not obtained until the time of surgery, and histological analysis is not available until the post-operative period. Neurosurgeons thus rely heavily on neuroimaging for operative planning. A scenario that frequently poses a diagnostic dilemma for radiologists and neurosurgeons is distinguishing between brain metastases and high-grade glioma on MRI. Magnetic resonance fingerprinting (MRF) is a novel MRI technique that allows quantification of multiple tissue properties by dynamically varying the pulse sequence parameters during a single acquisition. Currently, little is known about the ability of MRF to define brain tumours; thus, the purpose of this study was to help address the gap in this knowledge. Methods: MRF acquisitions were performed in 20 patients with intra-axial brain tumours: 11 high-grade gliomas and nine metastases. Regions of interest (ROIs) were manually drawn on MRF scans to delineate enhancing solid tumour, non-enhancing solid tumour, peritumour oedema, distant oedema and cystic areas, with diagnostic T1, T2, FLAIR and post-contrast sequences for reference. T1 and T2 relaxometry times from segmented voxels were extracted. Statistical comparisons of the means for each ROI were performed by using the univariate Wilcoxon rank sum test. A Naive Bayes classifier was used to predict tumour type based on T1/T2 relaxometry times. Results: Mean T2 relaxometry time across the enhancing solid tumour region could differentiate high-grade gliomas from metastases (mean, 75 ± 11 ms, and 58 ± 12 ms, respectively; p = 0.0044, significant after Bonferroni correction). The Naive Bayes classifier sorted glioblastomas and metastases with an AUC of 79%. Conclusion: MRF has the potential to improve diagnosis of brain pathologies and help overcome dilemmas differentiating between metastasis and high-grade glioma. Its application may further be applicable to differentiate between pathologies such as tumour recurrence and radiation necrosis. MRF has the potential to aid neurosurgeons when planning operations and guide them towards the correct treatment, thus improving patient outcomes. Background: Pre-treatment rebleeding of a ruptured cerebral aneurysm complicates nearly 9% of aneurysmal subarachnoid haemorrhage (aSAH) cases, increasing the 30-day case fatality rate by at least 50%. Over one quarter of survivors experience moderate to severe disability. Routine emergency treatment would reduce rebleeding but is impractical and existing predictive models show poor performance. Rebleeding occurs when aneurysm wall tension exceeds strength which can be computed. We demonstrate a semi-automated work-flow applied to admission CT imaging for patient-specific wall tension analysis that shows promise for distinguishing cases which re-bled from matched controls that did not. Methods: An illustrative case of saccular aSAH due to a 10 mm ACOM aneurysm complicated by rebleeding was identified from a 14-year state-wide database. This was matched to a control case which did not rebleed with similar size, location and re-bleeding propensity based on logistic regression of evidence-based risk factors. Non-contrast CT and CT-A DICOM images were in medical imaging analysis where images were and and semi-automated using the validated the were to a volume by a wall of was performed using the in the This volume was for an internal pressure of and of The including maps of distribution that internal was for the case than for the matched Conclusion: this case not a statistically significant we demonstrate a technique requiring and with clinical A propensity matched study is being performed to statistical prior to prospective of Introduction: are an that most commonly as tinnitus or an on imaging may also with intracranial haemorrhage or a where there is via of the subarachnoid have a risk of haemorrhage rate in the of between and per are there is limited available and ongoing the risk of haemorrhage of high-grade The aim of this study is to further assess this risk based on retrospective data from a centre in Methods: selected from to 2023 were by a The for follow-up was from the of first or the was the of complete or the latest MRI high or the of intracranial with follow-up than or to a and those without a or MRI were with intracranial haemorrhage on first presentation without prior imaging diagnosis were also Results: A total of cases were were initially 1 of prior to diagnosis, 1 paediatric patient and 1 due to 16 were due to haemorrhage on first presentation and were due to follow-up of 1 or A total of patients had years of follow-up = median = 4 patients suffered haemorrhage after diagnosis. The haemorrhage rate was as per per Of the cases due to follow-up a all had 16 of which were performed Conclusions: This retrospective analysis of high in patients with over one of follow up an haemorrhage risk of This is at the of range in the research into of high at risk for haemorrhage is The data that support the findings of this study are available from the reasonable

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