Use of fuzzy edge single-photon emission computed tomography analysis in definite Alzheimer's disease - a retrospective study

<p>Abstract</p> <p>Background</p> <p>Definite Alzheimer's disease (AD) requires neuropathological confirmation. Single-photon emission computed tomography (SPECT) may enhance diagnostic accuracy, but due to restricted sensitivity and specificity, the role of SPECT is largely limited with regard to this purpose.</p> <p>Methods</p> <p>We propose a new method of SPECT data analysis. The method is based on a combination of parietal lobe selection (as regions-of-interest (ROI)), 3D fuzzy edge detection, and 3D watershed transformation. We applied the algorithm to three-dimensional SPECT images of human brains and compared the number of watershed regions inside the ROI between AD patients and controls. The Student's two-sample t-test was used for testing domain number equity in both groups.</p> <p>Results</p> <p>AD patients had a significantly reduced number of watershed regions compared to controls (<it>p </it>< 0.01). A sensitivity of 94.1% and specificity of 80% was obtained with a threshold value of 57.11 for the watershed domain number. The narrowing of the SPECT analysis to parietal regions leads to a substantial increase in both sensitivity and specificity.</p> <p>Conclusions</p> <p>Our non-invasive, relatively low-cost, and easy method can contribute to a more precise diagnosis of AD.</p

The Durban stroke data bank with special emphasis on higher cortical function deficits.

Thesis (M.D.)-University of Natal, Durban, 1998.Background: Stroke is a leading cause of death and morbidity in all countries, yet treatment options are few. Numerous agents that were successful in animal models, failed in humans. Establishing the cause of stroke in the individual patient from the heterogeneous stroke mechanisms and measurement of clinical deficit including cognitive impairment in stroke are pivotal in successful treatment. An indigenous stroke data bank was established with specific emphasis on aetiology of stroke and higher cortical function measurement. Aim: 1. Establishment of an indigenous stroke data bank using contemporary neuroinvestigative modalities to determine stroke mechanism as precisely as possible. 2. To determine in this population, the frequency and extent of cognitive disorders in the acute and subacute stroke period, using a battery of predefined higher cortical function tests applied to all patients. 3. Collation of a comprehensive array of epidemiological, clinical, investigative and prognostic variables in complete digitised storage form. Methods: The patient population was a hospital based consecutive case series with an inpatient and outpatient stroke service in association with an acute stroke unit. A three tier investigative protocol was devised to incorporate contemporary neuroinvestigative modalities. All patients had mandatory investigations of stroke relevant blood tests, electrocardiogram, chest radiograph and brain scan. All patients were evaluated with a comprehensive battery of predefined, bedside higher cortical function tests. Standardised neurological deficit, clinical stroke scales, aetiological scales and disability scales were incorporated to quantitate deficit, stroke subtype and handicap at presentation. All patients were evaluated by the author and all information digitised by the author into the computerised registry - Durban Stroke Data Bank (DSDB). Results 1. Stroke Data Bank Issues: The first 1000 patients evaluated comprised of 561 men, 439 women, 781 Whites, 103 Asian Indians, 100 Blacks, 14 of Mixed Race and 2 other race groups. All patients had either a CT brain scan (698;69.8%), MRI brain scan (426;42.6%) or both (124;12.4%). Single Photon Emission Computed Tomography scans were performed in 104 (10.4%). Among the 23 different symptoms coded for, long tract signs, vision abnormalities and speech impairment predominated but 150 (15%) had additional other symptoms not coded for. Among the 29 different risk factors coded for, hypertension (42.1%), smoking (26.7%), cardiac illness (17.7%), Diabetes Mellitus (10.4%) and carotid stenosis (25.1%) were the most numerous. Approximately 96 different causes and possible causes of stroke were identified. The clinical ischaemic stroke classification (OCSP) revealed partial anterior circulation strokes in 447 (44.7%), posterior circulation in 258 (25.8%), total anterior circulation in 185 (18.5%) and lacunar in 82 (8.2%). The aetiological classification identified a large proportion of strokes due to "other" (253;25.3%) causes as opposed to large (264;26.4%) and small vessel disease (262;26.2%) or cardioembolism (122;12.2%). In 99 (9.9%) patients no cause could be established. The haemorrhage group was small (48;4.8%). Comparison of the clinical and aetiological classifications showed a significant difference overall (Chi square p-value=0.001). Black race had relatively higher other causes (39%) and unknown (20%) causes as did the young stroke (8-49 years) population; other (46.5%) and unknown (19.1%). Final aetiological classification differed significantly in young versus old in all categories (p=0.001) except cardioembolism (p=0.884). Admission neurological deficit (CNS) score compared to admission disability score (Rankin) showed moderate correlation with a Kappa value of 0.543. 2. Cognitive issues: One or more higher cortical function abnormalities was detected in 60.7% of non drowsy (drowsy, coma or delirious n=45) patients. The most numerous categories were aphasias (25.2%), apraxias (14.5%), amnesias (11.6%) and frontal systems syndromes (9.2%). In 76 patients, neuropsychological testing, (used as the gold standard) was performed and comparison to the HCFD test revealed a sensitivity of 80.2% (CI: 72-88%) and specificity of 100%. Cognitive impairment occurred without elementary neurological deficits (motor, sensory or visual i mpairment) in 137/608 (22.5%). Univariate and multivariate analyses of risk factors and likelihood of developing a HCFD revealed that increasing age, black race, being overweight and recent infection were independent variables at a p value of 0.05. HCFD did not differ significantly in younger versus older patients (p=0.194). Frontal system syndromes were more common in subcortical (32.3%) versus cortical (23.5%) lesions and more common in younger versus older patients (p=0.001) Conclusions: I. Cognitive disturbance is present in the majority of all types of stroke. This necessitates a reliable appraisal of this form of neurological deficit in all stroke patients in order to measure the true extent of deficit and monitor treatment and rehabilitation. This has important consequences for acute treatment trials that depend on changes in quantifiable deficit. 2. At times cognitive disturbance may be the sole presentation of stroke, unaccompanied by long tract signs. Therefore inadequate HCFD assessment may miss the deficit altogether. 3. Subcortical stroke is commonly associated with cognitive impairment - usually of a frontal system impairment. Such deficits are best correlated with functional brain scanning and not anatomical brain scanning. This is consistent with the network theory of brain functioning. 4. Risk factors for developing cognitive impairment in the indigenous stroke population included increasing age, black race, overweight body habitus and recent infection. This is an important message for the local population as the latter two are amenable to preventative measures. 5. In the young stroke population, although causes of stroke were numerous, prothrombotic states, infection associated strokes and dissection were the most numerous. All are amenable to primary preventative measures and treatable in the acute phase of stroke. 6. The Durban Stroke Data Bank showed that at least two dozen symptoms in stroke are important. In some instances, the diagnosis of stroke may be missed altogether if a wide array of symptoms are not entertained on presentation. 7. There were important black white differences in stroke with black people being younger with an increasing rate of HIV associated stroke being, documented. 8. Clinical and aetiological post investigative classification is useful in the management of stroke patients with significant differences found in all subgroups. This guides early, emergent stroke investigations and management

Atlas based image reconstruction for diffuse optical imaging of the human brain

Diffuse Optical Tomography (DOT) has been applied to imaging functional activations in the adult brain. Registered-atlas models are acceptable alternative forward models for the subject-specific models. In this work, different landmark-based rigid registration methods are quantitatively evaluated and compared in geometrical accuracy of the registration result, accuracy of light propagation approximation and recovery accuracy of the brain activations based on the whole head and localized head regions. The most suitable registration methods are selected based on accuracy and efficiency and they vary based on region of interest. For example, the most suitable registration method for recovery of whole cortex activation is the registration method based on 19 landmarks from the EEG 10/20 system and non-iterative Point to Point algorithms (EEG19nP2P registration). Efficiency of the recovery process is another popular research area in DOT. In this work, a modified generation approach of the light propagation approximation is designed based on a reduced sensitivity matrix and parallelisation process. It improves the storage efficiency by >1000% and time efficiency by ~400%. Based on this approach, the brain activation recovery of DOT can be processed on a normal laptop without large memory requirements within 45 minutes which is more suitable for a portable system

Applications and Experiences of Quality Control

The rich palette of topics set out in this book provides a sufficiently broad overview of the developments in the field of quality control. By providing detailed information on various aspects of quality control, this book can serve as a basis for starting interdisciplinary cooperation, which has increasingly become an integral part of scientific and applied research

Case series of breast fillers and how things may go wrong: radiology point of view

INTRODUCTION: Breast augmentation is a procedure opted by women to overcome sagging breast due to breastfeeding or aging as well as small breast size. Recent years have shown the emergence of a variety of injectable materials on market as breast fillers. These injectable breast fillers have swiftly gained popularity among women, considering the minimal invasiveness of the procedure, nullifying the need for terrifying surgery. Little do they know that the procedure may pose detrimental complications, while visualization of breast parenchyma infiltrated by these fillers is also deemed substandard; posing diagnostic challenges. We present a case series of three patients with prior history of hyaluronic acid and collagen breast injections. REPORT: The first patient is a 37-year-old lady who presented to casualty with worsening shortness of breath, non-productive cough, central chest pain; associated with fever and chills for 2-weeks duration. The second patient is a 34-year-old lady who complained of cough, fever and haemoptysis; associated with shortness of breath for 1-week duration. CT in these cases revealed non thrombotic wedge-shaped peripheral air-space densities. The third patient is a 37‐year‐old female with right breast pain, swelling and redness for 2- weeks duration. Previous collagen breast injection performed 1 year ago had impeded sonographic visualization of the breast parenchyma. MRI breasts showed multiple non- enhancing round and oval shaped lesions exhibiting fat intensity. CONCLUSION: Radiologists should be familiar with the potential risks and hazards as well as limitations of imaging posed by breast fillers such that MRI is required as problem-solving tool

Characterization of alar ligament on 3.0T MRI: a cross-sectional study in IIUM Medical Centre, Kuantan

INTRODUCTION: The main purpose of the study is to compare the normal anatomy of alar ligament on MRI between male and female. The specific objectives are to assess the prevalence of alar ligament visualized on MRI, to describe its characteristics in term of its course, shape and signal homogeneity and to find differences in alar ligament signal intensity between male and female. This study also aims to determine the association between the heights of respondents with alar ligament signal intensity and dimensions. MATERIALS & METHODS: 50 healthy volunteers were studied on 3.0T MR scanner Siemens Magnetom Spectra using 2-mm proton density, T2 and fat-suppression sequences. Alar ligament is depicted in 3 planes and the visualization and variability of the ligament courses, shapes and signal intensity characteristics were determined. The alar ligament dimensions were also measured. RESULTS: Alar ligament was best depicted in coronal plane, followed by sagittal and axial planes. The orientations were laterally ascending in most of the subjects (60%), predominantly oval in shaped (54%) and 67% showed inhomogenous signal. No significant difference of alar ligament signal intensity between male and female respondents. No significant association was found between the heights of the respondents with alar ligament signal intensity and dimensions. CONCLUSION: Employing a 3.0T MR scanner, the alar ligament is best portrayed on coronal plane, followed by sagittal and axial planes. However, tremendous variability of alar ligament as depicted in our data shows that caution needs to be exercised when evaluating alar ligament, especially during circumstances of injury

[¹⁸F]fluorination of biorelevant arylboronic acid pinacol ester scaffolds synthesized by convergence techniques

Aim: The development of small molecules through convergent multicomponent reactions (MCR) has been boosted during the last decade due to the ability to synthesize, virtually without any side-products, numerous small drug-like molecules with several degrees of structural diversity.(1) The association of positron emission tomography (PET) labeling techniques in line with the “one-pot” development of biologically active compounds has the potential to become relevant not only for the evaluation and characterization of those MCR products through molecular imaging, but also to increase the library of radiotracers available. Therefore, since the [18F]fluorination of arylboronic acid pinacol ester derivatives tolerates electron-poor and electro-rich arenes and various functional groups,(2) the main goal of this research work was to achieve the 18F-radiolabeling of several different molecules synthesized through MCR. Materials and Methods: [18F]Fluorination of boronic acid pinacol esters was first extensively optimized using a benzaldehyde derivative in relation to the ideal amount of Cu(II) catalyst and precursor to be used, as well as the reaction solvent. Radiochemical conversion (RCC) yields were assessed by TLC-SG. The optimized radiolabeling conditions were subsequently applied to several structurally different MCR scaffolds comprising biologically relevant pharmacophores (e.g. β-lactam, morpholine, tetrazole, oxazole) that were synthesized to specifically contain a boronic acid pinacol ester group. Results: Radiolabeling with fluorine-18 was achieved with volumes (800 μl) and activities (≤ 2 GBq) compatible with most radiochemistry techniques and modules. In summary, an increase in the quantities of precursor or Cu(II) catalyst lead to higher conversion yields. An optimal amount of precursor (0.06 mmol) and Cu(OTf)2(py)4 (0.04 mmol) was defined for further reactions, with DMA being a preferential solvent over DMF. RCC yields from 15% to 76%, depending on the scaffold, were reproducibly achieved. Interestingly, it was noticed that the structure of the scaffolds, beyond the arylboronic acid, exerts some influence in the final RCC, with electron-withdrawing groups in the para position apparently enhancing the radiolabeling yield. Conclusion: The developed method with high RCC and reproducibility has the potential to be applied in line with MCR and also has a possibility to be incorporated in a later stage of this convergent “one-pot” synthesis strategy. Further studies are currently ongoing to apply this radiolabeling concept to fluorine-containing approved drugs whose boronic acid pinacol ester precursors can be synthesized through MCR (e.g. atorvastatin)

Brain Tumors

Brain tumors comprise a spectrum of histological patterns. Their presentation and management depend on their location, size, and grade of lesions. This book is a collection of high-quality research work from global experts on brain tumors, including meningiomas, and their treatment