Resting state effective connectivity between inferior parietal lobe (IPL) and inferior temporal gyrus (ITG) in the left and right hemispheres

Inferior parietal lobule (IPL) and inferior temporal gyrus (ITG) are two important brain regions for the default mode network (DMN). IPL has been known to be involved in the control of attention and responding to given information while ITG is involved in the processing and perception awakened by visual stimuli. These two key DMN regions are highly interconnected as determined from white matter and fiber tracking studies. However, little is known about their nature of connectivity while the brain is at rest, whether it is linear, bilinear or nonlinear and whether it is of mono- or bi-direction. Resting state functional magnetic resonance imaging (rsfMRI) data were obtained from 7 healthy male and female participants (average age = 20.7 ± 4.5 years) and were concatenated. Data were analyzed using statistical parametric mapping (SPM12). Endogenous brain signals were modelled by Fourier series at 0.01 – 0.08 Hz. IPL-ITG connected linear, bilinear and non-linear causal models in both hemispheres were constructed and estimated by means of stochastic 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 significant level (pFWE 1000) which has the best balance between model accuracy and difficulty. The minimum free energy (F) = -4.41 × 104 and -4.09 × 104 for left and right hemisphere bilinear models respectively. From BMS and DCM results, it was found that IPL and ITG do have a dynamic collaboration between each other, a connectivity that belongs to a greater network when the brain is at rest. The intrinsic connections between them are negative in both directions i.e. IPL and ITG mutually inhibited each other. The effective connectivity was modulated by the endogenous fluctuation of the brain signal

First Reported Case of Neuroleptospirosis Complicated With Anton's Syndrome

Leptospirosis is a spirochetal zoonotic disease with a wide clinical spectrum, often underdiagnosed especially when presented as an acute neurological manifestation. We report a case of a 24-year-old man with serologically positive leptospirosis, who presented with altered sensorium, seizures and subsequently developed cortical blindness. His brain MRI revealed bilateral occipital and later parietal lobe cerebritis

Resting-state fMRI: comparing default mode network connectivity between normal and low auditory working memory groups

The relationship between resting effective connectivity (EC) among default mode network (DMN) regions and auditory working memory (AWM) performance is still poorly understood. In this work, resting-state functional magnetic resonance imaging (rsfMRI) was used to determine the optimum connectivity model between posterior cingulate cortex (PCC) and medial prefrontal cortex (mPFC) in 40 healthy male volunteers. in low and normal working memory groups of subjects. Correlation between EC with AWM performance and AWM-capacity was also studied. The participants were divided into two groups which are normal and low AWM-capacity groups based on Malay Version Auditory Verbal Learning Test. The AWM performance was assessed using a word-based backward recall task. Both assessments were conducted outside the MRI scanner. The participants were scanned using a 3-T MRI system and the data were analyzed using statistical parametric mapping (SPM12) and spectral Dynamic Causal Modelling (spDCM). Results revealed that PCC and mPFC were significantly interconnected in both groups. Group analyses showed that the connection between PCC and mPFC exhibits an anti-correlated network. The results also indicated that the AWM performance and AWM-capacity were not associated with EC. These findings suggest that EC at rest between the two regions may not significantly influence cognitive abilities important for this AWM task

Successful intravenous thrombolysis of a wake-up stroke with underlying valvular atrial fibrillation

A 42-year-old female admitted with new-onset atrial fibrillation had a wake-up stroke on the high-dependency unit and the time last seen well (TLSW) was 6.5 h. She suffered left-sided body weakness and her National Institutes of Health Stroke Scale (NIHSS) score was 17. An emergency CT perfusion showed right M1 segment occlusion with more than 50% penumbra. She was given recombinant tissue plasminogen activator (r-tPA) at 9 h from TLSW. An immediate diagnostic angiogram with intention to treat, owing to the presence of large vessel occlusion, showed complete reperfusion after intravenous r-tPA. She was discharged with NIHSS of 2, and at 3-month follow up her Modified Rankin Scale was 0. We demonstrated a successful reperfusion and excellent clinical recovery with intravenous thrombolysis in a patient who presented with a wake-up stroke with underlying valvular atrial fibrillation despite evidence of large vessel occlusion. © 2018, Royal College of Physicians of Edinburgh. All rights reserved

Spinal Schwannomatosis Mimicking Metastatic Extramedullary Spinal Tumor

Intradural extramedullary (IDEM) tumors are the most commonly observed intraspinal tumors, comprising over 60% of tumors found within the spinal canal, and the vast majority of these lesions are benign lesions. IDEM metastases are rare, but if they occur, they commonly manifest as leptomeningeal disease, secondary to drop lesions from intracranial metastases from adenocarcinomas of the lung, prostate cancer, breast cancer, melanoma, or rarely, as a result of lymphomas. The purely non-neurogenic origin of IDEM metastases is rare. Herein, we describe a patient with a previous history of treated colon cancer who presented with a progressive neurological deficit and whose imaging revealed multiple intradural, extramedullary and osseous lesions at the cervical and thoracolumbar spines. With the previous known primary and multiplicity of the lesions, an initial diagnosis of spinal metastasis was made, But it was proven to be schwannoma on histology. We emphasize the diagnostic dilemma in this case and the importance of detecting subtle imaging findings, which may be helpful to differentiate between metastatic disease and a second primary tumor

Predicting Outcome of Trial of Voiding Without Catheter in Acute Urinary Retention with Intravesical Prostatic Protrusion

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

A Comparison of Dynamic Contrast-Enhanced Magnetic Resonance Imaging and T2-Weighted Imaging in Determining the Depth of Myometrial Invasion in Endometrial Carcinoma—A Retrospective Study

This study aims to compare dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with T2-weighted imaging (T2WI) in defining the depth of myometrial invasion in endometrial carcinoma. This retrospective study included 32 subjects with endometrial carcinoma who underwent 3.0T magnetic resonance imaging (MRI) prior to hysterectomy. DCE-MRI and T2WI were evaluated to determine the depth of myometrial invasion in endometrial carcinoma. A set of data consisting of the sensitivity, specificity, predictive values, and accuracy of DCE-MRI and T2WI were obtained and compared with the histopathological results. Out of the 32 cases included, the histopathological examination revealed that 50% myometrial invasion was found in 11 patients and ≥50% myometrial invasion was found in 21 patients. In the assessment of the tumor invasion, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of T2WI were 45.45%, 90.48 %, 71.43%, 76.0%, and 75.0%, respectively. The corresponding values for DCE-MRI were 81.82%, 76.19%, 64.29%, 88.89 %, and 78.12%, respectively. When T2WI were read together with DCE-MRI, the values were 90.91%, 90.48%, 83.33%, 95.0%, and 90.62%, respectively. Thus, the sensitivity and accuracy of DCE-MRI were greater compared to T2WI in defining the depth of myometrial invasion. However, the merging of T2WI and DCE-MRI increased the specificity and PPV value and improved the sensitivity, NPV and accuracy in detecting myometrial invasion. DCE-MRI was more sensitive but less specific than T2WI in defining the depth of myometrial invasion. In conclusion, combining DCE-MRI and T2WI further improves the diagnostic performance for myometrial invasion in endometrial carcinoma

Evaluation of time-dependent pathways in an acute ischemic stroke protocol that incorporates CT perfusion: A tertiary referral center experience

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

Pituitary apoplexy: a rare cause of middle cerebral artery infarction

Pituitary apoplexy is a well-known complication of a pituitary adenoma. However, an ischaemic event caused by pituitary apoplexy is rare. We reported a case of pituitary apoplexy with middle cerebral artery infarction in a 44-year old man who presented with a sudden onset of altered sensorium. Vasospasm is the most likely underlying cause of the infarction in this case secondary to transdiaphragmatic rupture of the sella tumour into the subarachnoid space

Sellar and parasellar lesions: a pictorial illustration

Learning Objective: To present imaging characteristics of various common and uncommon Sellar and Parasellar lesions. Brief Content: The Sella Turcica and adjacent area is a small but complex part of the central nervous system. It contains many structures that can give rise to myriad of pathological lesion. This pictorial exhibit will review common and some uncommon types of pathological processes that occur in this region. Some of the lesions that will be displayed will include: Pituitary Microadenoma, Macroadenoma, Pituitary Apoplexy, Rathke cleft cyst, empty Sella, Aneurysms, Epidermoid/Dermoid, Metastases, Craniopharyngioma, Germinoma, Arachnoid Cyst, Tuber Cinerium Hamartoma, Chiasmatic Glioma, , Lymphocytic Hypophysitis, and Infundibular Histiocytosi