Search results for " Scanning"
showing 10 items of 988 documents
Cocaine abuse determination by ion mobility spectrometry using molecular imprinting
2016
A cocaine-based molecular imprinted polymer (MIP) has been produced by bulk polymerization and employed as selective solid-phase extraction support for the determination of cocaine in saliva samples by ion mobility spectrometry (IMS). The most appropriate conditions for washing and elution of cocaine from MIPs were studied and MIPs were characterized in terms of analyte binding capacity, reusability in water and saliva analysis, imprinting factor and selectivity were established and compared with non-imprinted polymers. The proposed MIP-IMS method provided a LOD of 18μgL-1 and quantitative recoveries for blank saliva samples spiked from 75 to 500μgL-1 cocaine. Oral fluid samples were collec…
Reproducibility of multiphase pseudo-continuous arterial spin labeling and the effect of post-processing analysis methods
2015
Arterial spin labeling (ASL) is an emerging MRI technique for non-invasive measurement of cerebral blood flow (CBF). Compared to invasive perfusion imaging modalities, ASL suffers from low sensitivity due to poor signal-to-noise ratio (SNR), susceptibility to motion artifacts and low spatial resolution, all of which limit its reliability. In this work, the effects of various state of the art image processing techniques for addressing these ASL limitations are investigated. A processing pipeline consisting of motion correction, ASL motion correction imprecision removal, temporal and spatial filtering, partial volume effect correction, and CBF quantification was developed and assessed. To fur…
Usefulness of quantitative peritumoural perfusion and proton spectroscopic magnetic resonance imaging evaluation in differentiating brain gliomas fro…
2016
Objectives The purpose of our study was to evaluate whether peritumoural perfusion weighted and proton spectroscopic magnetic resonance imaging can be used in differentiating between primary gliomas and solitary metastases. Methods Ten low-grade gliomas, eight high-grade gliomas and 10 metastases were prospectively evaluated with magnetic resonance imaging, dynamic susceptibility contrast enhanced perfusion imaging and single-voxel proton magnetic resonance spectroscopy before surgical resection or stereotactic biopsy. Maximal relative cerebral blood volume values were calculated drawing three regions of interest of 2 cm2 in the non-enhancing peritumoural areas. Maximal relative cerebral bl…
Collagen ultrastructure in ruptured cruciate ligaments
1992
The ultrastructure of collagen fibrils was investigated in normal (n 39) and ruptured (n 23) human anterior cruciate ligaments. The normal ligament had a complex three-dimensional structure. Collagen fibrils predominantly had a unidirectional course with parallel arrangement and a mean diameter of 75 (20-185) nm. Four days after anterior cruciate ligament rupture, the mean fibril diameter was increased; it later decreased, probably due to synthesis of young, thin 30-40 nm fibrils. Interfibrillar dysplastic collagen fibrils were detected in the extracellular matrix of ruptured ligaments. They were more frequently found later than 3 days after rupture and were seen also at a distance of 2-3 c…
Scanning electron microscopic and X ray microanalysis study of the mineral deposits in pseudoxanthoma elasticum.
1977
A skin biopsy of a 37 year old man with typical lesions of pseudoxanthoma clasticum (P.E.) associated with angioid streaks (Groenblad-Strandberg Syndrom) was examined with a scanning E. M. (SEM) and a SEM provided with a X ray micro-analyser. The SEM provided with X ray microanalyser enabled us to see the correspondence between the crystalline deposits and a calcium salt. The potassium, sodium and magnesium analysis of the specimen permits us to verify that the P.E. dermis is rich in K and poor in Mg.
Clinicopathological and ultrastructural characterization of periapical actinomycosis
2019
Background The aim of the present study was to analyze the clinicopathological and the ultrastructural features of periapical actinomycosis (PA) cases. Material and Methods Data from the files of an oral pathology laboratory were retrieved and the findings of histopathological analysis were evaluated. Hematoxylin–eosin (HE), a modified Brown & Brenn, and Grocott stains as well as ultrastructural analysis using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were utilized. Results Six cases were obtained, 4 females and 2 males, with a mean age of 34 year-old. Two cases were symptomatic, lower teeth and the anterior region were more commonly affected, and all…
Infrequent early recanalization of greater saphenous vein after endovenous laser treatment
2003
Abstract Objective The frequency of recanalization of the greater saphenous vein (GSV) after endovenous laser treatment (ELT) is unclear. This study was undertaken to establish the incidence of early recanalization after ELT and to study the histopathologic features of reperfused and excised GSV. Methods One hundred nine GSV in 85 consecutive patients with clinical stage C 2-6 E P,S A S,P,D P R disease were treated with ELT. Twelve months of follow-up with duplex scanning at regular intervals was possible in 104 treated veins (95.4%) in 82 patients (96.5%). Recanalized vessels were removed surgically and examined at histopathology. Results ELT-induced occlusion proved permanent at duplex sc…
Flicker Defined Form Perimetry in Glaucoma Suspects with Normal Achromatic Visual Fields
2014
To evaluate if repeated flicker-defined form (FDF) perimetry can detect visual field (VF) defects in glaucoma suspects with normal findings in achromatic standard automated perimetry (SAP).Patients with optic nerve heads (ONHs) or retinal nerve fiber layer (RNFL) findings clinically suspicious for glaucoma and normal SAP were enrolled. Patients underwent VF testing with FDF perimetry (Heidelberg Edge Perimetry, HEP) at two consecutive visits (HEP I and HEP II) and confocal scanning laser ophthalmoscopy with the Heidelberg Retina Tomograph (HRT). Abnormal HEP was defined by cluster-point analysis (CPA) and by the HEP specific glaucoma hemi-field test (GHT). Results were compared with an age-…
Ultrastructural study by backscattered electron imaging and elemental microanalysis of biomaterial-to-bone interface and mineral degradation of bovin…
2012
Objectives The aim of this study was to perform an ultrastructural study of the bone-to-biomaterial interface and biomaterial mineral degradation in retrieved bone biopsies following maxillary sinus augmentation using bovine xenografts (Endobon®) in 15 clinical cases. Materials and methods Nine months after sinus lifting, bone cores were harvested from the maxillary sinus. The specimens were processed for observation under a scanning electron microscope with backscattered electron imaging (SEM-BSE). In addition, chemical analysis and elemental mapping of the mineral composition were generated using a microanalytical system based on energy-dispersive X-ray spectrometry (EDX). Results No clin…
FAIR and dynamic susceptibility contrast-enhanced perfusion imaging in healthy subjects and stroke patients.
2002
Purpose To compare dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) and the flow-sensitive alternating inversion recovery (FAIR) technique for measuring brain perfusion. Materials and Methods We investigated 12 patients with acute stroke, and 10 healthy volunteers with FAIR and DSC maps of regional cerebral blood volume (rCBV), mean transit time (MTT), and regional cerebral blood flow (rCBF). Results In volunteers good gray/white-matter contrast was observed in FAIR, rCBF, and rCBV maps. Regions with high signal intensities in FAIR matched well with high values of rCBV and rCBF. In ischemic stroke patients a high correlation (r = 0.78) of the ipsi- to contralate…