1,720,995 research outputs found
Joint Metabonomic and Instrumental Analysis for the Classification of Migraine Patients with 677-MTHFR Mutations
Full text linkMigraine is a neurological disorder that correlates with an increased risk of cerebrovascular lesions. Genetic mutations of the MTHFR gene are correlated to migraine and to the increased risk of artery pathologies. Also, migraine patients show altered hematochemical parameters, linked to an impaired platelet aggregation mechanism. Hence, the vascular assessment of migraineurs is of primary importance.
Transcranial Doppler sonography (TCD) is used to measure cerebral blood flow velocity (CBFV) and vasomotor reactivity (by an index measured during breath-holding – BHI). Aim of this study was the metabolic profiling of migraine subjects with T/T677-MTHFR and C/T677-MTHFR mutations and its correlation with CBFV and BHI.
Metabonomic multidimensional techniques were used to describe and cluster subjects. Fifty women suffering from migraine (age: 18-64; 21 with aura) underwent TCD examination, hematochemical blood analysis, Born test, and genetic tests for MTHFR mutation. Fourteen (7 with aura) had T/T677, 18 (8 with aura) had C/T677, and 18 (6 with aura) had no mutation. The total number of variables was 24.
Unsupervised and supervised techniques_showed the correlation between CBFV and BHI with mutation. Discriminant analysis allowed for classifying the subjects with 95.9% sensitivity and 89.0% specificity. Aura was not correlated to mutation or variations of instrumental data.
Our study showed that metabonomics could be effectively applied in clinical problems to show the overall correlation structure of complex systems in pathology. Specifically, our results confirmed the importance of TCD in the metabolic profiling and follow-up of migraine patients.</jats:p
"CALSFOAM - completed automated local statistics based first order absolute moment" for carotid wall recognition, segmentation and IMT measurement: validation and bench-marking on a 300 patient database.
No full textAIM: In this work we present a novel methodology (called CALSFOAM) for the automated segmentation of ultrasound carotid images and intima-media thickness (IMT) measurement. CALSFOAM was developed in order to overcome limitations of a previously developed snake-based technique.
METHODS: CALSFOAM consists of two stages: Stage-I is an automatic recognition of the carotid artery system in an image frame and Stage-II is a combination of segmentation and IMT measurement sub-system. Stage-I is performed by using local statistics and by automatically tracing the profile of the distal adventitia. Stage-II takes the traced adventitia boundary and builds an ROI for distal wall segmentation that uses a first order absolute moment (FOAM) technique. CALSFOAM was benchmarked against our previous snake based technique and validated on a 300-image multi-institutional dataset.
RESULTS: CALSFOAM’s lumen-intima (LI) segmentation error was 0.049±0.039 mm, the media-adventitia (MA) error was 0.088±0.054 mm; the IMT measurement bias was 0.125±0.103 mm. To reduce CALSFOAM error, we adopted a GREEDY approach for fusing the boundaries from the two techniques and obtained LI and MA errors equal to 0.02±0.014 mm, 0.023±0.013 mm, and an IMT bias of 0.074±0.068 mm.
CONCLUSION: Even though CALSFOAM’s performance was lower than snake-based segmentation techniques, it helped in avoiding possible inaccuracies of snakes and its parameter sensitivities. The very accurate performance obtained by the GREEDY approach demonstrated that the two techniques could be considered as complementary
NIRS applied to the analysis of cerebral hemodynamics in normal and pathological subjects
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Cerebral Hemodynamics Assessed by means of Trasncranial Doppler and Near - Infrared Spectroscopy in Healthy Smokers and non-Smokers
No full textThe assessment of cerebral vasomotor reactivity (VMR) is a valuable tool for the early detection of risk condition in healthy subjects and for the non-invasive bedside evaluation of patients. Typically, cerebral hemodynamics assessment is performed in correspondence of CO2 reactivity. We studied the VMR of a population of young healthy non-smokers (n=10, age 27 plusmn 4.1) and healthy smokers (n=4, age 28 plusmn 4.5) using a joint approach based on transcranial Doppler ultrasonography and near-infrared spectroscopy, to monitor cerebral blood flow velocity (CBFV) and concentrations of oxygenated (O2Hb) and reduced (CO2Hb) haemoglobin. VMR was induced by means of voluntary breath-holding (BH). We quantified VMR using the breath-holding index (BHI). Smokers BH duration was significantly lower than that of non-smokers (p < 10-4; their BHI did not significantly differ from that of non-smokers in terms of CBFV, but differed in terms of O2Hb and CO2Hb concentrations changes. Specifically, with respect to non-smokers, smokers presented a delayed VMR that took place only around 60% of the apnoea phase. This delayed response could reveal an impaired autoregulatory mechanism and could be a risk condition when the subjects need to compensate an abrupt change in the cerebral blood flo
Ultrasonography and MR Imaging in Progressive Supranuclear Palsy
No full textProgressive supranuclear palsy (PSP) also known as Steele, Richardson and Olszewski disorder is a neurodegenerative brain disease that has no known cause, treatment or cure. PSP has no known geographical, occupational or racial preference and affects brain cells that control walking, balance, mobility, vision, speech and swallowing. Symptoms begin on average in the early 60s, but may start as early as in the 40s: a good history and physical examination support the clinical diagnosis and latency of each feature makes us suspect a probable PSP, an atypical Parkinsonism. The diagnosis of a large number of cases of PSP is missed or delayed: 75% of the patients are never clinically diagnosed by neurologist and in most cases the median interval between onset and diagnosis is three years. Notwithstanding such differences in clinical presentation, there remains an overlap in symptoms making the differential diagnosis between such neurodegenerative disorders challenging. A few imaging techniques developed to evaluate brain anatomy and function are used extensively to improve the diagnostic accuracy of different forms of Parkinsonism. Noninvasive and safe methods can now document brain structures. Transcranial sonography (TCS) is a very low cost tool to assess the basal ganglia and mesencephalic echogenicity. Conventional magnetic resonance imaging (MRI) is a valuable tool to exclude secondary Parkinsonism. Our purpose is to define characteristic objectively measured imaging markers that point out normal biological processes, and pathogenic processes in PSP. Such markers should be sufficiently sensitive and specific to show the underlying biological disease and the pharmacological responses to therap
Relationship between oxygen supply and cerebral blood flow assessed by transcranial Doppler and near-infrared spectroscopy in healthy subjects during breath-holding
Full text linkAbstract Background Breath – holding (BH) is a suitable method for inducing cerebral vasomotor reactivity (VMR). The assessment of VMR is of clinical importance for the early detection of risk conditions and for the follow-up of disabled patients. Transcranial Doppler ultrasonography (TCD) is used to measure cerebral blood flow velocity (CBFV) during BH, whereas near-infrared spectroscopy (NIRS) measures the concentrations of the oxygenated (O2Hb) and reduced (CO2Hb) hemoglobin. The two techniques provide circulatory and functional-related parameters. The aim of the study is the analysis of the relationship between oxygen supply and CBFV as detected by TCD and NIRS in healthy subjects performing BH. Methods 20 healthy subjects (15 males and 5 females, age 33 ± 4.5 years) underwent TCD and NIRS examination during voluntary breath – holding. VMR was quantified by means of the breath-holding index (BHI). We evaluated the BHI based on mean CBFV, O2Hb and CO2Hb concentrations, relating the baseline to post-stimulus values. To quantify VMR we also computed the slope of the linear regression line of the concentration signals during BH. From the NIRS signals we also derived the bidimensional representation of VMR, plotting the instantaneous O2Hb concentration vs the CO2Hb concentration during the BH phase. Two subjects, a 30 years old current smoker female and a 63 years old male with a ischemic stroke event at the left middle cerebral artery, were tested as case studies. Results The BHI for the CBFV was equal to 1.28 ± 0.71 %/s, the BHI for the O2Hb to 0.055 ± 0.037 μmol/l/s and the BHI for CO2Hb to 0.0006 ± 0.0019 μmol/l/s, the O2Hb slope was equal to 0.15 ± 0.09 μmol/l/s and the CO2Hb slope to 0.09 ± 0.04 μmol/l/s. There was a positive correlation between the CBFV and the O2Hb increments during BH (r = 0.865). The bidimensional VMR pattern shows common features among healthy subjects that are lost in the control studies. Conclusion We show that healthy subjects present a common VMR pattern when counteracting cerebral blood flow perturbations induced by voluntary BH. The proposed methodology allows for the monitoring of changes in the VMR pattern, hence it could be used for assessing the efficacy of neurorehabilitation protocols.</p
CULEX - Completely User-independent Layers EXtraction: Ultrasonic carotid artery images segmentation
No full textThe analysis of the carotid wall is of paramount importance in clinical practice. In fact, the intima-media thickness is a risk index for some of the most severe acute cerebrovascular pathologies; hence, the need for an accurate segmentation of the different layers of the carotid artery. In the past ten years, a wide variety of algorithms for the carotid tunica segmentation have been proposed, but they require a certain degree of user interaction. In this paper we propose a novel approach to the completely user-independent segmentation of the carotid artery wall. Our algorithm has been designed for the extraction of the intima and media layers of the distal carotid wall, based on ultrasonic B-mode images. We evaluated the performance of the algorithm on a set of 63 images and compared the automatic segmentation to that traced by a trained operator. We obtained a mean error lower than 1.3 pixel both on the intima and media layers, which is comparable to that obtained by means of operator dependent technique
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