Search results for "radio"
showing 10 items of 8895 documents
RCBF-quantification with 99mTc-HMPAO-SPECT: theory and first results.
1989
The activity concentrations of 99mTc-HMPAO in brain after intravenous injection were evaluated in 25 patients using SPECT. With additional first pass studies of heart and brain with the short lived isotope 195mAu, the cardiac output and the mean cerebral transit times of the patients were measured a short time before the HMPAO injection. The time dependence of 99mTc-HMPAO activity in the brain was registered during the first 5 min after injection over both hemispheres. Using a simplified three compartment model it was possible to calculate the mean retention fraction of HMPAO in brain from the time activity curves. It could be shown that the regional cerebral blood flow in ml/min per 100 g …
Carotid artery intima-media thickness: normal and percentile values in the Italian population (camp study)
2011
AIMS: Carotid intima-media thickness (IMT) is one of the best non-invasive parameters for evaluating previous vascular lesions and could be used to identify a preclinical stage of the atherosclerotic process. The aim of our research was to develop an epidemiological study of the normal mean values of IMT of the common carotid artery, adjusted for age and sex, in the Italian population. METHODS AND RESULTS: In this multicenter study, a total of 1017 patients (596 males, mean age: 58.5 + 13.2 years) were enrolled at four different Italian centers. Inclusion criteria were the absence of cardiovascular risk factors or presence of not more than one. Patients underwent two-dimensional echo-color …
Relation between diagnosis of atheromatous plaque from orthopantomographs and cardiovascular risk factors. A study of cases and control subjects.
2014
Background In recent years the use of orthopantomography has been proposed as a low-cost, reliable and non-invasive diagnostic medium for detecting atheromatous plaque. The purpose of this study was to correlate the presence of carotid calcifications (atheroma) in orthopantomographs with specific risk factors for cerebrovascular accidents (previous cerebrovascular accidents, arterial hypertension, and diabetes). Material and Methods The methods used in this observational study of cases and control subjects followed STROBE (Strengthening the Reporting of Observational studies in Epidemiology) recommendations. The study analyzed a total of 1,602 panoramic radiographs taken for dental diagnost…
Pre- and intraoperative methods of controlling cerebral circulation in giant aneurysm surgery.
1995
The surgical treatment of giant aneurysms usually requires temporary clipping of the aneurysmatic vessel. In planning the surgical approach and in applying temporary clips, the surgeon must consider collateral circulations. The functional integrity of the collateral vessels frequently decides the patient's outcome. In 8 patients with internal carotid artery giant aneurysm, measurements of blood flow velocities in the ipsilateral middle cerebral artery were performed preoperatively with transcranial Doppler ultrasound (TCD) during manual occlusion of the carotid artery at the neck. Three different perfusion patterns were established, and each collateral capacity was rated as insufficient, te…
Calcified carotid artery atheromas on panoramic radiographs of head and neck cancer patients before and after radiotherapy
2017
Background The aims of this study were to verify if head and neck radiotherapy (RT) is able to induce calcified carotid artery atheroma (CCAA) in a large head and neck cancer (HNC) population and also to compare the socio-demographic and clinical findings of patients with and without CCAA detected on panoramic radiographs. Material and Methods Panoramic radiographs taken before and after head and neck radiotherapy (RT) of 180 HNC patients were selected and analyzed in order to identify the presence of CCAA. In addition, CCAA presence or absence on panoramic radiographs were compared and correlated with clinicopathological findings. Results A high overall prevalence of CCAA was found on pano…
Cerebral blood flow, computerized tomography and angiography in 562 cases of cerebrovascular insufficiency
1987
The measurement of cerebral blood flow (CBF) in addition to cerebral computerized tomography (CT) and angiography is most reliable in cases of transient ischemic attacks (TIA) and prolonged reversible ischemic neurologic deficits (PRIND). Alterations of CBF can be detected in symptom-free intervals. The cerebrovascular reactivity to CO2 stimulus is regarded as an especially suitable tool to prove the cerebrovascular reserve. If it is diminished, cerebral angiography should be carried out since it will often show major obstructive lesions. Angiography shows no sure correlation between CBF and collateral circulation. Strong opthalmic pathways in unilateral occlusion of the internal carotid ar…
Reproducibility of imaging human knee cartilage by delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) at 1.5 Tesla
2009
Summary Objective The purpose of this study was to investigate the day-to-day reproducibility of the delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) measurement at different knee joint surfaces in healthy subjects at 1.5 Tesla (T). Methods The dGEMRIC experiment was repeated for 10 asymptomatic volunteers three times with an average interval of 5 days between scans. The measurement was performed from a single sagittal slice through the center of the lateral femoral condyle and from the center of the patella in the axial plane. Cartilage was manually segmented into superficial, deep and full-thickness regions of interests (ROIs) at different topographical locations of the femur, tibia…
Assessment of normal patellar cartilage volume and thickness using MRI: an analysis of currently available pulse sequences.
1996
Objective. The objective of this study was to analyse the potential of magnetic resonance imaging for valid determination of patellar cartilage thickness, comparing currently available pulse sequences. Design. In six patients and one cadaver the cartilage was repetitively imaged employing three spin-echo and six three-dimensional gradient-echo sequences. In the cadaveric specimen the total volume and the regional distribution of cartilage thickness were assessed and compared with the values obtained from anatomical sections by image analysis. Results and conclusions. The FLASH and fat-suppressed FLASH sequences allowed the most accurate determination of the cartilage volume and thickness. F…
Facilitating cartilage volume measurement using MRI.
2010
To compare quantitative cartilage volume measurement (CVM) using different slice thicknesses.Ten knees were scanned with a 1.5T MRI (Sonata, Siemens, Erlangen, Germany) using a 3D gradient echo sequence (FLASH, fast low-angle shot). Cartilage volume of the medial and lateral tibial plateau was measured by two independent readers in 1.5mm, 3.0mm and 5.0mm slices using the Argus software application. Accuracy and time effectiveness served as control parameters.Determining cartilage volume, time for calculation diminished for the lateral tibial plateau from 384.6+/-127.7s and 379.1+/-117.6s to 214.9+/-109.9s and 213.9+/-102.2s to 122.1+/-60.1s and 126.8+/-56.2s and for the medial tibial platea…
Magnetic resonance chondro-crassometry (MR CCM): a method for accurate determination of articular cartilage thickness?
1996
A method for the assessment of articular cartilage thickness based on MRI is presented and its accuracy and reproducibility tested. Six specimens of human patellae were imaged, using a fat-suppressed FLASH 3D sequence, and sectioned with a high-precision band saw. The regional distribution of articular cartilage thickness was determined from the MR images and from the anatomical sections (intervals of 0.5 mm). With image analysis 50-90% of the image points were found to lie within exactly the same thickness interval in corresponding patterns, and less than 17% deviated more than 0.5 mm. More than 85% of all pixels were reproducible with MRI after new positioning of the joint. No influence o…