ABSTRACT
Inferior parietal lobule (IPL) and inferior temporal gyrus (ITG) are two important brain regions for the default modenetwork (DMN). IPL has been known to be involved in the control of attention and responding to given information whileITG is involved in the processing and perception awakened by visual stimuli. These two key DMN regions are highlyinterconnected as determined from white matter and fiber tracking studies. However, little is known about their natureof connectivity while the brain is at rest, whether it is linear, bilinear or nonlinear and whether it is of mono- or bidirection.Resting state functional magnetic resonance imaging (rsfMRI) data were obtained from 7 healthy male andfemale participants (average age = 20.7 ± 4.5 years) and were concatenated. Data were analyzed using statisticalparametric mapping (SPM12). Endogenous brain signals were modelled by Fourier series at 0.01 – 0.08 Hz. IPL-ITGconnected linear, bilinear and non-linear causal models in both hemispheres were constructed and estimated by means ofstochastic dynamic causal modelling (sDCM) and were compared using Bayesian Model Selection (BMS) for group studies.Group fixed-effects results indicated that bilateral IPL and ITG exhibited high neural activity at a corrected significantlevel (pFWE 1000) which has the best balance betweenmodel accuracy and difficulty. The minimum free energy (F) = -4.41 × 104 and -4.09 × 104 for left and right hemispherebilinear models respectively. From BMS and DCM results, it was found that IPL and ITG do have a dynamic collaborationbetween each other, a connectivity that belongs to a greater network when the brain is at rest. The intrinsic connectionsbetween them are negative in both directions i.e. IPL and ITG mutually inhibited each other. The effective connectivitywas modulated by the endogenous fluctuation of the brain signal.
ABSTRACT
Cerebral amyloid angiopathy (CAA) accounts for approximately 10–20% of spontaneous intracerebral haemorrhage (ICH). This figure is thought to be higher in the elderly population. With the increasing life expectancy of our population, we anticipate that the prevalence of CAA- related ICH will increase in tandem. Although CAA-related ICH and hypertension-related ICH are distinct entities based on histopathology and imaging, the clinical presentation of the two conditions is similar. The use of brain computed tomography (CT) scans remain the ICH imaging modality of choice in Malaysia due to its availability, cost, and sensitivity in detecting acute bleeds. On the other hand, the use of brain magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) sequencing enables the clinician to determine the presence of chronic blood products in the brain, especially clinically silent microbleeds associated with CAA. However, the use of brain MRI scans in our country is limited and leads to a blurring of lines when differentiating between hypertension-related ICH and CAA-related ICH. How this misrepresentation affects the management of these conditions is unclear. In this study, we present two cases of ICH to illustrate this point and to serve as a springboard to question current practice and promote discussion.
ABSTRACT
Background and Objective: Intravenous thrombolysis service for stroke was introduced at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in 2009, based on the recommendations of a multidisciplinary team of clinicians. We report the experience at our center in establishing a stroke protocol incorporating computed tomography perfusion (CTP) of the brain, to assess the feasibility of incorporating CTP in the stroke protocol. Methods: A retrospective review of all patients who had a CTP between January 2010 and December 2011 was performed. Results: Of 272 patients who were admitted with acute ischemic stroke, 44 (16.2%) arrived within 4.5 hours from symptom onset and had a CTP performed with the intention to treat. The median time for symptom-to-door, symptom-to-scan and door-to-scan was 90.0 minutes (62.5 – 146.3), 211.0 minutes (165.5 – 273.5) and 85.0 minutes (48.0 – 144.8) respectively. Eight patients (2.9%) were thrombolysed of whom five received IV thrombolysis and three underwent mechanical thrombolysis. The median symptom-to-needle and door-to-needle times were 290.5 minutes (261.3 – 405.0) and 225.0 minutes (172.5 – 316.8) respectively. Four patients were thrombolysed despite being outside the window of treatment based on the CTP findings. Six of the thrombolysed patients had a Modified Rankin Score (MRS) of 1-2 at 5 months post procedure. Conclusions: CTP provides a benefit to management decisions and subsequent patient outcome. It is feasible to incorporate CTP as a standard imaging modality in a stroke protocol. The delays in the time-dependent pathways are due to our work flow and organisational process rather than performing the CTP per se.
ABSTRACT
Background: Acute urinary retention (AUR) is one of the most serious complications of benign prostatic hypertrophy. This study was done to predict the outcome of trial of voiding without catheter (TWOC) in patients with AUR with intravesical prostatic protrusion (IPP) detected on transabdominal ultrasound. Other factors such as prostatic volume and patient’s age were also assessed. Method: Patients with a first episode of AUR secondary to benign prostatic hypertrophy were assessed with ultrasound following bladder catheterization. The IPP was measured and graded (grade 1 is 5 mm or less, grade 2 is 5–10 mm and grade 3 is more than 10 mm). Success of TWOC was then correlated with the degree of IPP. Results: A total of 32 patients with AUR were included in the study. Patients with grade 3 IPP were found to have a significant failure rate compared to grade 1 (P = 0.022) and grade 2 (P = 0.041). Conclusion: Intravesical prostatic protrusion is a useful predictor of success of TWOC in patients with AUR. Patients with grade 3 IPP on ultrasound would benefit from TWOC and warrant earlier definitive surgical treatment.
ABSTRACT
Giant-cell arteritis is an infl ammatory disease of blood vessels most commonly involving large and medium arteries of the head, predominately the branches of the external carotid artery. It is a form of vasculitis. Giant-cell arteritis of the temporal artery is referred to as “temporal arteritis”. Giant cell arteritis is rare among Asians. Diagnosis is based on American College of Rheumatology (ACR) classifi cation criteria for giant-cell arteritis with gold standard temporal artery biopsy.1 Blindness is a feared complication, mostly caused by anterior ischaemic optic neuropathy. High-resolution magnetic resonance imaging (MRI) has started to play a role in the diagnosis of giant cell arteritis. Evidence of arteritis involving the superfi cial temporal arteries with mural thickening and even the ophthalmic arteries can be seen on MRI, which further increase the diagnostic confi dence prior to biopsy.2,3 Optic perineuritis is a rare association with giant cell arteritis. MRI is required for diagnosis especially for differentiation from optic neuritis.4 We report a case of giant cell arteritis with optic perineuritis to demonstrate the role of MRI in the diagnosis.
ABSTRACT
We report a case of a 13-year-old boy who complained of progressive abdominal distension and symptoms of anaemia. Radiological investigations revealed that the child had a hypervascular tumour of the inferior vena cava (IVC). Unfortunately, the child presented with acute lower gastrointestinal bleed soon after the investigation. He underwent an urgent pre-operative embolisation, aimed to reduce the tumour vascularity. A total resection of the tumour, right nephrectomy, and partial duodenal resection were done within 24 hours post-embolisation. The child was stable postoperatively. The histopathological examination revealed chromogranin-positive paraganglioma originating from the IVC. We highlight the radiological findings of rare primary IVC paraganglioma and the role of embolisation prior to surgical removal of the tumour.