Paediatric neurovascular anomalies associated with the vein of Galen (VG) comprise of a spectrum of rare, complex, and life-threatening conditions. In this group, the “vein of Galen aneurysmal dilatation” (VGAD) is a distinct entity that often presents with progressive neurological symptoms in older children. Acute haemorrhage in VGAD is uncommon. We present an unusual presentation of VGAD in a neonate and discuss the challenges faced in the management.

Introduction Aneurysmal subarachnoid haemorrhage (aSAH) is a condition with significant morbidity and mortality. Traditional markers of aSAH have established their utility in the prediction of aSAH outcomes while frailty markers have been validated in other surgical specialties. We aimed to compare the predictive value of frailty indices and markers of sarcopaenia and osteopaenia, against the traditional markers for aSAH outcomes. Methods An observational study in a tertiary neurosurgical unit on 51 consecutive patients with ruptured aSAH was performed. The best performing marker in predicting the modified Rankin scale (mRS) on discharge was selected and an appropriate threshold for the definition of frail and non-frail was derived. We compared various frailty indices (modified frailty index 11, and 5, and the National Surgical Quality Improvement Program score [NSQIP]) and markers of sarcopaenia and osteopaenia (temporalis [TMT] and zygoma thickness), against traditional markers (age, World Federation of Neurological Surgery and modified Fisher scale [MFS]) for aSAH outcomes. Univariable and multivariable analysis was then performed for various inpatient and long-term outcomes. Results TMT was the best performing marker in our cohort with an AUC of 0.82, Somers’ D statistic of 0.63 and Tau statistic 0.25. Of the frailty scores, the NSQIP performed the best (AUC 0.69), at levels comparable to traditional markers of aSAH, such as MFS (AUC 0.68). The threshold of 5.5 mm in TMT thickness was found to have a specificity of 0.93, sensitivity of 0.51, positive predictive value of 0.95 and negative predictive value of 0.42. After multivariate analysis, patients with TMT ≥ 5.5 mm (defined as non-frail), were less likely to experience delayed cerebral ischaemia (OR 0.11 [0.01 – 0.93], p = 0.042), any complications (OR 0.20 [0.06 – 0.069], p = 0.011), and had a larger proportion of favourable mRS on discharge (95.0% vs. 58.1%, p = 0.024) and at 3-months (95.0% vs. 64.5%, p = 0.048). However, the gap between unfavourable and favourable mRS was insignificant at the comparison of 1-year outcomes. Conclusion TMT, as a marker of sarcopaenia, correlated well with the presenting status, and outcomes of aSAH. Frailty, as defined by NSQIP, performed at levels equivalent to aSAH scores of clinical relevance, suggesting that, in patients presenting with acute brain injury, both non-neurological and neurological factors were complementary in the determination of eventual clinical outcomes. Further validation of these markers, in addition to exploration of other relevant frailty indices, may help to better prognosticate aSAH outcomes and allow for a precision medicine approach to decision making and optimization of best outcomes.

Purpose To assess the difference in optic nerve tortuosity during eye movements and globe proptosis between primary open angle glaucoma and normal subjects using orbital magnetic resonance imaging. Methods 10 Chinese subjects matched for age, ethnicity and refractive errors were recruited, including five normal controls and five patients with primary open angle glaucoma. All subjects underwent magnetic resonance imaging to assess their optic nerves and globes for three eye positions: primary gaze, adduction and abduction. Optic nerve tortuosity (optic nerve length divided by the distance between two ends) and globe proptosis (maximum distance between cornea and interzygomatic line) were measured from magnetic resonance imaging images. Results In adduction, the tortuosity of normal eyes was significantly larger than that of the glaucomatous eyes. Optic nerve tortuosity in adduction in the control and glaucoma groups were 1.004±0.003 (mean ± standard deviation) and 1.001±0.001, respectively (p=0.037). Globe proptosis (primary gaze) in glaucoma subjects (19.14±2.11 mm) was significantly higher than that in control subjects (15.32±2.79 mm; p = 0.046). Conclusions In this sample, subjects with glaucoma exhibited more taut optic nerves and more protruding eye globes compared to normal eyes. This may impact optic nerve head deformations in anatomically predisposed patients. Précis Eyes with glaucoma have tauter optic nerves compared with normal eyes, which may exert more force on the optic nerve head tissues during eye movements.

In response to the demands of an ageing nation, the postgraduate medical education in Singapore is currently in the early stage of transition into the American-styled residency programme. This study assessed the expectations of both radiology trainees and faculty on their ideal clinical learning environment (CLE) which facilitates the programme development. A modified 23-item questionnaire was administered to both trainees and faculty at a local training hospital. All items were scored according to their envisioned level of importance and categorised into 5 main CLE domains supervision, formal training programme, work-based learning, social atmosphere and workload. 'Supervision' was identified as the most important domain of the CLE by both trainees and faculty, followed by 'formal training programmes', 'work-based learning' and 'social atmosphere'. 'Workload' was rated as the least important domain. For all domains, the reported expectation between both trainees and faculty respondents did not differ significantly. Intragroup comparison also showed no significant difference within each group of respondents. This study has provided valuable insights on both respondents' expectations on their ideal CLE that can best train competency in future radiologists. Various approaches to address these concerns were also discussed. The similarities in findings between ours and previous studies suggest that the 'supervision', 'formal training programmes' and 'work-based learning' domains are crucial for the success of a postgraduate medical training and should be emphasised in future curriculum. 'Workload' remains a challenge in postgraduate medical training, but attempts to address this will have an impact in future radiology training.

This article will review the uncommon locations and morphological features of meningiomas, which are important to recognize in order to avoid misdiagnosis. Uncommon locations will be demonstrated at the cerebellopontine angle, pineal, optic, intraventricular, and intradiploic regions. Unusual imaging features including cysts, metaplastic changes, and peritumoural oedema will also be discussed.

Objectives: Cone-beam computed tomography (CBCT) in sinonasal imaging is fairly novel and remains limited to date. This study aimed to compare (1) the image quality of CBCT and multidetector computed tomography (MDCT), and (2) the eye lens dose for paranasal sinus imaging between these two modes of imaging. Methods: This study was approved by an institutional ethics review board. Sixteen patients underwent CT imaging of their paranasal sinuses for the evaluation of chronic rhinosinusitis using both CBCT and MDCT. The eye lens dose was measured using lithium fluoride thermoluminescent dosimeters during each scan. The scans were read independently by two readers for the presence of sinonasal opacification, artefacts, clarity of osseous structures and soft tissues (based on 5-point grading scales). The interclass coefficient was used to assess interobserver variability. Results: The mean eye lens dose was 1.0 mGy on CBCT and 1.4 mGy on MDCT. Respective grading scores for opacification, artefacts, osseous structures, and soft tissues were 4.3, 3.9, 4.0 and 2.0 on CBCT compared with 4.2, 4.3, 4.6 and 4.2 on MDCT. Score differences between CBCT and MDCT for artefacts, osseous structures, and soft tissues were statistically significant (p < 0.05). Conclusion: The image quality of CBCT scans was generally inferior, but adequate for screening purposes in the assessment of opacification and osseous detail. Compared with MDCT scans, the mean eye lens dose with CBCT was also lowered by 25%.

microcatheters using a mixture of tissue glue and lipiodol, a radio-opaque oil-based contrast agent that can alter the viscosity and polymerisation time of tissue glue based on the percentage of dilution.2 Based on preand post-embolisation angiograms, the proportion of AVM nidus obliterated and parenchymal loss of the treated kidney were estimated, performed with simple eyeballing by an experienced radiologist. The patients were followed-up clinically for recurrence of symptoms, and by imaging when necessary.

Purpose: To study the clinical course with regard to both the angiographic and visual outcomes of carotid cavernous fistulas (CCFs). Background: Carotid cavernous sinus fistulas (CCFs) are conditions which often present with ocular signs and symptoms. The clinical presentation of CCFs is varied according to the anatomy, haemodynamics and size of the CCF. CCFs causing significant symptoms or vision loss should be treated with embolization.Methods: This is a retrospective review of the medical records of all CCF cases seen in the Singapore National Eye Centre from September 2002 to December 2011.Results: 45 patients who had confirmed CCF on conventional cerebral angiography were included. Anterior draining CCFs presented with orbital congestion while posterior draining CCFs presented with pain, diplopia and cranial nerve palsies. Mild residual symptoms were still present in 85% of treated direct CCFs despite complete angiographic closure however 52% of treated dural CCFs had complete resolution of symptoms despite only half of those achieving angiographic closure. Treated and untreated dural CCFs had similar outcomes (87% versus 76% recovered or improved (p > 0.05)). Poor outcomes can result from residual diplopia or vision loss from complications of the CCF itself (e.g. compressive optic neuropathy, glaucoma, retinopathy) or complications from CCF embolization treatment (e.g. central retinal artery occlusion).Conclusion: Presenting symptoms and signs are related to the angiographic drainage of CCFs. Angiographic outcomes after embolization treatment may not always correlate with clinical outcomes.

Spinal perimedullary arteriovenous fistula (AVF) or dural arteriovenous fistula (DAVF) presenting as intracranial subarachnoid haemorrhage (SAH) is uncommon. A total of 16 cases have been reported to date. A majority of the reports described cervical spinal DAVF, while two other case reports described intracranial SAH secondary to lumbar and thoracic DAVF, respectively. We report a 61-year-old Chinese man with intracranial SAH secondary to thoracic DAVF aneurysm, who presented with sudden, severe chest pain, initially suggestive of aortic dissection/acute myocardial infarction. However, a careful examination of the history and physical signs, followed by appropriate and timely investigations enabled effective treatment to be administered promptly with a good outcome. This serves to illustrate the importance of investigating the entire cerebrospinal system when neurological symptoms and clinical signs suggest extracranial primary pathology.

Background: A tumefactive demyelinating lesion (TDL) often masquerades as a brain tumour and poses a diagnostic dilemma which may result in unnecessary surgery in some rare cases. This case emphasizes the need for caution when confronted with a patient whose differential diagnosis is between TDL and neoplasm.Summary of report: A 31-year-old woman was diagnosed as having a brain neoplasm. She was referred to our institution for further diagnostic imaging and treatment. Structural and physiologic scan were performed and these findings suggested a TDL rather than a neoplasm. Stereotactic biopsy of the lesion showed findings in keeping with demyelinating disease. The patient received steroid treatment, and showed improvement.Conclusion: The utility of the physiologic technique with structural scan may lead to an increased accuracy in differentiating TDL from neoplasm. (C) 2010 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

INTRODUCTION This study aims to analyse the results of carotid stenting in a tertiary referral centre in Singapore. MATERIALS AND METHODS Retrospective analysis of all carotid artery stenting (CAS) cases in a single centre from March 1997 to December 2008 was performed. Sixty successful procedures were performed in 61 patients, with bilateral stenting in 1 patient, and 2 failed procedures. The majority were Chinese (78.7%) and males (77.0%), with a high proportion having hypertension (82.0%) and hypercholesterolaemia (78.7%). The majority (91.8%) of patients were high surgical risk candidates, primarily due to cardiac risk factors. Ten patients (16.4%) had prior neck irradiation for nasopharyngeal carcinoma, and 3 patients each (4.9%) had previous endarterectomy and contralateral occlusion. A distal embolic protection device was used in 71.7% of cases. RESULTS Technical success was 96.8%. The 30-day stroke and death rate was 13.8%, comparable to reported results for this high surgical risk population. CONCLUSION CAS is a technically feasible and a relatively safe alternative to endarterectomy to treat extracranial carotid stenosis, especially in patients who are inoperable or at high surgical risk.

The dual energy CT (DECT) technology has been recently employed in the form of two X-ray sources of different energies to enhance the contrast between adjacent structures. Its use in the cardiac arena has been widely highlighted due to the higher temporal resolution. However, it may also be used in the craniocervical and peripheral vasculature for better differentiation between contrast-enhanced vascular lumina and calcified plaques, in the characterisation of ureteric stones, and in the evaluation of hepatic lesions. The objective of this paper is to revisit DECT physics, review the literature and discuss its use in CT neuroangiography with case illustrations from our institution, and impact on dose savings.

Idiopathic Normal Pressure Hydrocephalus (NPH) is a debilitating condition of the elderly. The patient is typically "wet, wobbly and wonky", to different degrees of the triad. The diagnosis is supported by the radiologic finding of dilated ventricles, determined by an elevated Evan's Index (EI) without a demonstrable cause. Patients with newly diagnosed NPH typically respond to ventriculo-peritoneal shunting (VPS). NPH-related dementia is possibly the only surgically reversible dementia. An elevated cerebrospinal fluid (CSF) fl ow rate (FR) is associated with a positive response to shunting. However, post-shunting EI and FRs are unpredictable. Of late, intracranial apparent diffusion coefficient (ADC) quantification via Diffusion Weighted Imaging (DWI) has been emerging as a possible marker in NPH diagnosis. A local study, conducted on a national level, to study the relationship of EI, FR and ADC to pre- and post-shunt clinical measurements has just ended. This review seeks to reconcile the current thinking of NPH, magnetic resonance imaging (MRI) quantification and clinical evaluation, and in the process shed some light on major pathophysiological determinants of the disease.

INTRODUCTION:Functional magnetic resonance imaging (fMRI) is a neuroradiological technique for the localisation of cortical function. FMRI made its debut in cognitive neuroscience and then eventually to other clinical applications. We report our experience with pre-surgical fMRI on a high field scanner, based purely on a clinical platform.MATERIALS AND METHODS:The protocols included motor, auditory, visual and language fMRI. The choice of protocols was dependant on clinical request and lesion locale.RESULTS:Retrospective analysis and audit of the fi rst 30 consecutive patients over a 12-month period revealed that about 85% of patients had a successful examination. In a pictorial essay, we demonstrate that patients with weakness in performing a motor task showed abnormal activations of the pre-motor and supplementary motor areas.CONCLUSION:FMRI data greatly enhances the pre-surgical planning process and the conduct of surgery when it is incorporated into the surgical navigation system in the operating theatre.

INTRODUCTION:Systemic and local intra-arterial thrombolysis in patients with large vessel ischaemic stroke is hampered by poor re-canalisation rates and risk of haemorrhage. The Merci Retrieval System is an endovascular device for removal of acute intracranial thrombus. We present our initial experience using this device in conjunction with existing thrombolytic therapy already in place in our institute.MATERIALS AND METHODS:Prospective data in all patients presenting with large vessel ischaemic stroke treated using the Merci Retrieval System from July 2007 to March 2009 were analysed. Selection criteria for patients were similar to the multi- Merci trial of 2008. We compared re-canalisation rate, National Institutes of Health Stroke Score (NIHSS) and modified Rankin score (mRS) outcomes to the published trial results.RESULTS:Seventeen patients were reviewed; none suffered immediate post-procedural complications. Fifteen underwent successful thrombus retrieval but in 2 cases the device failed due to technical considerations. Sites of vascular occlusion included: ICA/ICA-'T' junctions 27%, middle cerebral artery 13% and vertebrobasilar artery 60%. Of the 15 patients treated by MERCI with or without adjuvant thrombolytic therapy, complete re-canalisation was achieved in 60%, partial re-canalisation in 20%, partial re-canalisation with persistent distal vessel occlusion in 6% and failure of re-canalisation in 14%. Asymptomatic haemorrhage occurred in 33% and there was 1 death (6%) from symptomatic haemorrhage. Pre-treatment median NIHSS was 17.88 and 9.5 immediately post-treatment. Median mRS at 30 days was 2.6 for patients who achieved complete re-canalisation and 4.5 in failure or partial re-canalisation with or without persistent distal vessel occlusion.CONCLUSION:Re-canalisation rates using the Merci Retrieval System was comparable to the multi-Merci trial. Haemorrhagic complications and safety were also found to be satisfactory. Importantly, treatment success with eventual good clinical outcome hinges strongly on the ability of the device to achieve complete re-canalisation.