Cerebrovascular Disorders ; diagnostic imaging ; Clinical Medicine ; Humans ; Neuroradiography ; methods ; trends ; utilization ; Stroke ; diagnostic imaging

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.
Cerebral Angiography ; Constriction, Pathologic ; diagnosis ; Humans ; Image Interpretation, Computer-Assisted ; Intracranial Aneurysm ; diagnosis ; Radiation Dosage ; Radiography, Dual-Energy Scanned Projection ; methods ; Review Literature as Topic ; Tomography, X-Ray Computed ; methods

INTRODUCTIONSystemic 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 METHODSProspective 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.

RESULTSSeventeen 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.

CONCLUSIONRe-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.

Acute Disease ; Aged ; Cerebral Arteries ; diagnostic imaging ; physiopathology ; Cerebral Revascularization ; Female ; Humans ; Intracranial Thrombosis ; radiotherapy ; Male ; Middle Aged ; Outcome Assessment (Health Care) ; Prospective Studies ; Radiography ; Singapore ; Stroke ; pathology ; radiotherapy ; Thrombectomy ; instrumentation

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.
Attitude of Health Personnel ; Competency-Based Education ; Curriculum ; Education, Medical, Graduate ; methods ; organization & administration ; Faculty, Medical ; Female ; Humans ; Internship and Residency ; methods ; organization & administration ; Male ; Radiology ; education ; Singapore ; Students, Medical ; psychology ; Surveys and Questionnaires ; Workload

INTRODUCTIONFunctional 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 METHODSThe protocols included motor, auditory, visual and language fMRI. The choice of protocols was dependant on clinical request and lesion locale.

RESULTSRetrospective 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.

CONCLUSIONFMRI 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.

Adult ; Aged ; Diagnostic Techniques, Neurological ; Female ; Hospitals, General ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Preoperative Period ; Psychomotor Performance ; physiology ; Retrospective Studies ; Singapore

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.
Biomarkers ; cerebrospinal fluid ; Cerebrospinal Fluid ; physiology ; secretion ; Diffusion Magnetic Resonance Imaging ; Humans ; Hydrocephalus, Normal Pressure ; diagnosis ; physiopathology

INTRODUCTIONThis study aims to analyse the results of carotid stenting in a tertiary referral centre in Singapore.

MATERIALS AND METHODSRetrospective 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.

RESULTSTechnical success was 96.8%. The 30-day stroke and death rate was 13.8%, comparable to reported results for this high surgical risk population.

CONCLUSIONCAS 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.

Aged ; Aged, 80 and over ; Angioplasty ; methods ; Angioplasty, Balloon, Coronary ; methods ; Carotid Artery Diseases ; surgery ; Female ; Hospitals, General ; Humans ; Male ; Middle Aged ; Outcome Assessment (Health Care) ; Retrospective Studies ; Risk ; Singapore ; Stents

Adult ; Arteriovenous Malformations ; therapy ; Embolization, Therapeutic ; methods ; Enbucrilate ; therapeutic use ; Female ; Humans ; Kidney ; blood supply ; Male ; Middle Aged