Wavelet-Based Fractal Analysis of rs-fMRI for Classification of Alzheimer's Disease.

The resting-state functional magnetic resonance imaging (rs-fMRI) modality has gained widespread acceptance as a promising method for analyzing a variety of neurological and psychiatric diseases. It is established that resting-state neuroimaging data exhibit fractal behavior, manifested in the form of slow-decaying auto-correlation and power-law scaling of the power spectrum across low-frequency components. With this property, the rs-fMRI signal can be broken down into fractal and nonfractal components. The fractal nature originates from several sources, such as cardiac fluctuations, respiration and system noise, and carries no information on the brain's neuronal activities. As a result, the conventional correlation of rs-fMRI signals may not accurately reflect the functional dynamic of spontaneous neuronal activities. This problem can be solved by using a better representation of neuronal activities provided by the connectivity of nonfractal components. In this work, the nonfractal connectivity of rs-fMRI is used to distinguish Alzheimer's patients from healthy controls. The automated anatomical labeling (AAL) atlas is used to extract the blood-oxygenation-level-dependent time series signals from 116 brain regions, yielding a 116 × 116 nonfractal connectivity matrix. From this matrix, significant connections evaluated using the p-value are selected as an input to a classifier for the classification of Alzheimer's vs. normal controls. The nonfractal-based approach provides a good representation of the brain's neuronal activity. It outperformed the fractal and Pearson-based connectivity approaches by 16.4% and 17.2%, respectively. The classification algorithm developed based on the nonfractal connectivity feature and support vector machine classifier has shown an excellent performance, with an accuracy of 90.3% and 83.3% for the XHSLF dataset and ADNI dataset, respectively. For further validation of our proposed work, we combined the two datasets (XHSLF+ADNI) and still received an accuracy of 90.2%. The proposed work outperformed the recently published work by a margin of 8.18% and 11.2%, respectively.

Non-alcoholic fatty liver disease (NAFLD) and the cardiovascular disease (CVD) risk categories in primary care: is there an association?

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is an emerging novel cardiovascular disease (CVD) risk factor. It's prevalence is increasing globally. However, there is paucity in the evidence showing the association between NAFLD and CVD risk in primary care setting. Therefore, the objectives of this study were to determine the prevalence and factors associated with NAFLD among patients with ≥1 risk factor for NAFLD or CVD attending primary care clinics. METHODOLOGY: A cross sectional study was conducted in two clinics at a university primary care centre. Patients aged ≥18 years with ≥1 risk factor for NAFLD or CVD were recruited. Participants with history of established liver disease or chronic alcohol use were excluded. Socio-demographics, clinical related data, anthropometric measurements and blood investigation results were recorded in a proforma. Diagnosis of NAFLD was made using abdominal ultrasound. The 10-year CVD risk was calculated using the general Framingham Risk Score (FRS). Multiple logistic regression (MLogR) was performed to identify independent factors associated with NAFLD. RESULTS: A total of 263 participants were recruited. The mean age was 52.3 ± 14.7 years old. Male and female were equally distributed. Majority of the participants were Malays (79.8%). The overall prevalence of NAFLD was 54.4% (95%CI 48,60%). Participants in the high FRS category have higher prevalence of NAFLD (65.5%), followed by those in the moderate category (55.4%) and the low category (46.3%), p = 0.025. From MLogR, independent factors associated with NAFLD were being employed (OR = 2.44, 95%CI 1.26,4.70, p = 0.008), obesity with BMI ≥27.5 (OR = 2.89, 95%CI 1.21,6.91, p = 0.017), elevated fasting glucose ≥5.6 mmol/L (OR = 2.79, 95%CI 1.44,5.43, p = 0.002), ALT ≥34 U/L (OR = 3.70, 95%CI 1.85,7.44, p < 0.001) and high FRS category (OR = 2.82, 95%CI 1.28,6.23, p = 0.010). CONCLUSION: NAFLD is highly prevalent among patients with ≥1 risk factor for NAFLD or CVD in these primary care clinics. Patients who were obese, have elevated fasting glucose, elevated ALT and in the high FRS category were more likely to have NAFLD. This study underscores the importance of targeted screening for NAFLD in those with risk factors in primary care. Aggressive intervention must be executed in those with NAFLD in order to reduce CVD complications and risk of progression.

Onyx in Brain Arteriovenous Malformation Embolisation.

INTRODUCTION: Embolisation has long been used as an adjunct to surgical resection in the treatment of brain arteriovenous malformation (bAVM). The most commonly used embolic material, n-butylcyanoacrylate glue, requires experience and skill to handle its quick and unpredictable flow and polymerisation. A new liquid embolic agent, ethylene vinyl alcohol copolymer (Onyx), is less adhesive and polymerises slowly, which provides better control for radiologists performing embolisation. OBJECTIVE: To report our experience in embolisation using Onyx alone or in combination with histoacryl for bAVM embolisation in our tertiary referral centre. METHODS: We retrospectively reviewed the anatomy, technical conditions, complications and clinical outcome of all bAVM patients embolised at our centre using Onyx alone or in combination with n-butylcyanoacrylate glue. RESULTS: Between 2010 and 2013, 13 patients [6 (46.2%) male; 7 (53.8%) female; aged, 14-57 years] were included, and a total of 31 embolisations were performed. Clinical presentation included hemorrhage [9 (69.2%)], seizures [2 (15.4%)], and headache [2 (15.4%)]. Most AVMs were located in the brain hemispheres [12 (92.3%)] and measured <3 cm [7 (53.8%]. Complete occlusion of the AVM was obtained in 2 (15.4%) patients; 11 (84.6%) patients had partial occlusion [6 (54.5%) had <50% nidus occlusion]. Complications occurred in four procedures involving 3 patients (morbidity, 23.1%). This resulted in the death of 1 patient (mortality, 7.7%) and complete recovery with no disability in 2 patients. CONCLUSION: The total nidal occlusion achieved herein is comparable to other similar studies. Our morbidity and mortality were higher compared to other studies which may be attributed to the small number of patients. More data is being collected which may better reflect on our experience.

Atypical Clival Chordoma in an Adolescent without Imaging Evidence of Bone Involvement.

Clival chordoma is a rare primary bone tumour that arises from the remnant of the notochord and typically occurs in older adults. Upon imaging, the tumour can be seen arising from the clivus and causes clival destruction. This usually provides insight for a diagnosis. Here we present a case of a non-enhancing, pre-pontine mass that was hypointense on T1W and hyperintense on T2W in an adolescent. No clival bone erosion was observed. Based on the age group, imaging findings, and lack of clival erosion, a provisional diagnosis of epidermoid cyst was made and the tumour was resected. This patient was eventually diagnosed with a clival chordoma based on histopathological examination.

Suprasellar pilocytic astrocytoma with leptomeningeal dissemination.

Leptomeningeal dissemination is a rare manifestation of pilocytic astrocytoma. It may occur with higher-grade tumours like medulloblastoma, ependymoma and high-grade glioma, but is extremely rare with low-grade glioma. There has been a growing number of reported cases documenting leptomeningeal dissemination of pilocytic astrocytoma in the medical literature. Contribution: Description of a World Health Organization (WHO) Grade I suprasellar pilocytic astrocytoma with leptomeningeal dissemination in the brain and spinal cord which showed progression of the leptomeningeal nodules without tumour upgrading on long-term follow-up.

Uterine arteriovenous malformation.

Uterine arteriovenous malformation (AVM) is a rare condition, with fewer than 100 cases reported in the literature. Despite it being rare, it is a potentially life-threatening condition. This case report describes a 33-year-old woman who presented with secondary post-partum hemorrhage. Transabdominal ultrasound (US) of the pelvis showed increased vascularity with multidirectional flow of the uterus and a prominent vessel, located on the left lateral wall. She also had retained product of conception, which complicated the diagnosis. A uterine artery angiogram confirmed an AVM in the fundal region with an early draining vein. Embolisation of the AVM was performed successfully.

Tumefactive demyelinating lesions versus CNS neoplasms, a comparative study.

BACKGROUND: Differentiating tumefactive demyelinating lesions (TDL) from neoplasms of the central nervous system continues to be a diagnostic dilemma in many cases. OBJECTIVE: Our study aimed to examine and contrast the clinical and radiological characteristics of TDL, high-grade gliomas (HGG) and primary CNS lymphoma (CNSL). METHOD: This was a retrospective review of 66 patients (23 TDL, 31 HGG and 12 CNSL). Clinical and laboratory data were obtained. MRI brain at presentation were analyzed by two independent, blinded neuroradiologists. RESULTS: Patients with TDLs were younger and predominantly female. Sensorimotor deficits and ataxia were more common amongst TDL whereas headaches and altered mental status were associated with HGG and CNSL. Compared to HGG and CNSL, MRI characteristics supporting TDL included relatively smaller size, lack of or mild mass effect, incomplete peripheral rim enhancement, absence of central enhancement or restricted diffusion, lack of cortical involvement, and presence of remote white matter lesions on the index scan. Paradoxically, some TDLs may present atypically or radiologically mimic CNS lymphomas. CONCLUSION: Careful evaluation of clinical and radiological features helps in differentiating TDLs at first presentation from CNS neoplasms.

Detection of subtle white matter lesions in MRI through texture feature extraction and boundary delineation using an embedded clustering strategy.

White matter lesions (WML) underlie multiple brain disorders, and automatic WML segmentation is crucial to evaluate the natural disease course and effectiveness of clinical interventions, including drug discovery. Although recent research has achieved tremendous progress in WML segmentation, accurate detection of subtle WML present early in the disease course remains particularly challenging. Here we propose an approach to automatic WML segmentation of mild WML loads using an intensity standardisation technique, gray level co-occurrence matrix (GLCM) embedded clustering technique, and random forest (RF) classifier to extract texture features and identify morphology specific to true WML. We precisely define their boundaries through a local outlier factor (LOF) algorithm that identifies edge pixels by local density deviation relative to its neighbors. The automated approach was validated on 32 human subjects, demonstrating strong agreement and correlation (excluding one outlier) with manual delineation by a neuroradiologist through Intra-Class Correlation (ICC = 0.881, 95% CI 0.769, 0.941) and Pearson correlation (r = 0.895, p-value < 0.001), respectively, and outperforming three leading algorithms (Trimmed Mean Outlier Detection, Lesion Prediction Algorithm, and SALEM-LS) in five of the six established key metrics defined in the MICCAI Grand Challenge. By facilitating more accurate segmentation of subtle WML, this approach may enable earlier diagnosis and intervention.

An Infratemporal Meningioma: A Diagnostic Dilemma.

A 46-year-old male presented with painless, recurrent bilateral ear discharge and an enlarging right temporal swelling. There were no neurological deficits. Imaging revealed an enhancing, soft tissue mass at the right infratemporal region involving the right temporalis muscle with a small, enhancing intradural component and associated hyperostosis of the greater wing of the right sphenoid bone. Tumour debulking of the right temporalis tumour was performed. Tumour invasion of the right temporalis muscle was noted intraoperatively. Histopathological result was consistent with fibrous meningioma WHO Grade 1 involving surgical resection margins. Follow-up MRI revealed residual right temporal extracranial component. Thus, plans were made for a second stage tumour debulking, however at time of writing, surgery had not been performed. This case highlights the differing appearances of the common meningioma occurring extracranially with elaboration of its differential diagnosis and management.

Clival Chordoma in an Adolescent: A Perspective from Primary Care.

Clival chordoma is a rare malignant tumor of the brain that typically occurs in older adults. It has a high local recurrence rate and is hence associated with poor prognosis. Here, we report a case of an adolescent who presented with a 1-month history of worsening headache and blurring of vision, as well as a 6-month history of left-sided facial and body numbness. Clinical findings were consistent with left upper motor neuron lesion of the seventh cranial nerve with involvement of the fifth cranial nerve. He was also found to have a sixth cranial nerve palsy demonstrated by diplopia upon lateral gaze with no evidence of papilledema. Magnetic resonance imaging of the brain suggested clival chordoma. He was subsequently referred to the neurosurgical team, and he successfully underwent an endoscopic trans-sphenoidal surgery to excise the lesion. He recovered well, continued his follow-ups with the neurosurgical team, and showed good progress. He also attended regular follow-ups with his primary care physician to ensure ongoing psychosocial support and monitoring of his overall health status. This case demonstrates the importance of prompt identification and treatment of clival chordoma in an adolescent. Long-term follow-ups and shared care between primary and secondary care physicians are essential to monitor recurrence of tumor and to provide psychosocial support.

Metastatic hepatocellular carcinoma presenting as a sphenoid sinus mass and meningeal carcinomatosis.

We report the case of a 30-year-old woman who was referred to us for evaluation of a 2-week history of fever, headache, vomiting, bilateral ptosis, and blurred vision. Imaging obtained by the referring institution had identified a sphenoid sinus mass and diffuse meningeal infiltration, which was thought to represent an infective process. We subsequently identified the mass as a metastatic hepatocellular carcinoma (HCC). The patient was placed under palliative care, and she died 1 month later. Metastases to the sphenoid sinus from any primary source are very rare, and they are generally not considered in the radiologic differential diagnosis. HCC is known to metastasize to the lung, lymph nodes, and musculoskeletal system; again, reported cases of metastasis to the sphenoid sinus are rare. Indeed, our review of the English-language literature found only 6 previously reported cases of sinonasal metastasis of a primary HCC. A diagnosis of a sinonasal metastasis is more difficult in a patient who has no previous diagnosis of a primary malignancy. In presenting this case, our aim is to remind readers of this possibility.