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Aim: To evaluate the potential role of signal intensities calculated in T 2 images as an adjunctive parameter in the analysis of mass-like enhancements classified as BIRADS Breast Imaging Reporting and Data System assessment categories 2, 3, 4 or 5 with the standard T1 criteria. Materials and methods: After a retrospective review of breast Magnetic Resonance Imaging MRI performed for the evaluation of a suspicious lesion we selected a group of 65 mass-like enhancements ranging from 5 to 20 mm, classified as BIRADS assessment categories 2, 3, 4 or 5, histologically proved.
In all cases we calculated the ratio between the signal intensity SI of the nodule and the pectoralis major muscle LMSIR, lesion to muscle signal intensity ratio with a multiROIs region of interest analysis on T 2 images. Results: Histological examination assessed 34 malignant lesions This sequence was used in more than patients. Retrospective analysis of 80 patients with cerebrovascular and inflammatory disease was carried out.
The IR -RARE sequence proved to be particularly suitable for identifying small lesions in the neighbourhood of the subarachnoid space. We illustrate the typical contrast provided by this sequence , and describe its characteristics, exemplifying the advantages it offers for the diagnosis of multiple sclerosis, cerebral microangiopathy and brain infarction.
Basic evaluation of the new pulse sequence for simultaneous acquisition of T1- and T 2 -weighted images. A novel pulse sequence that enables simultaneous acquisition of T1-weighted T1W and T 2 -weighted T 2 W images is presented. By using a shorter T1 and independent k-space ordering, the first part of the sequence provides T 2 W images and the second part provides T1W images, thereby enabling simultaneous acquisition in a single scan time comparable to that of Fast IR.
Signal simulation also was conducted, and this was compared with conventional scanning techniques using normal volunteers. In the human studies, both T1W and T 2 W images showed the same image quality as conventional images, suggesting the potential for this technique to replace the combination of Fast IR and T 2 W FSE for scan-time reduction.
High signals in the uterine cervix on T 2 -weighted MRI sequences. The aim of this pictorial review was to illustrate the normal cervix appearance on T 2 -weighted images, and give a review of common or less common disorders of the uterine cervix that appear as high signal intensity lesions on T 2 -weighted sequences.
Numerous aetiologies dominated by cervical cancer are reviewed and discussed. This gamut is obviously incomplete; however, radiologists who perform MR women's imaging should perform T 2 -weighted sequences in the sagittal plane regardless of the indication for pelvic MR. Those sequences will diagnose some previously unknown cervical cancers as well as many other unknown cervical or uterine lesions.
Aim: To compare three-dimensional 3D isotropic T 2 -weighted magnetic resonance imaging MRI sequences and reformation with two-dimensional 2D T 2 -weighted sequences regarding image quality of the cervical spine at 3 T. Materials and methods: A phantom study was performed using a water-filled cylinder. The signal-to-noise and image homogeneity were evaluated. Multiplanar reformation MPR of the 3D T 2 -weighted sagittal dataset was performed simultaneously with image evaluation.
In addition to artefact assessment, the visibility of anatomical structures in the 3D and 2D sequences was qualitatively assessed by two radiologists independently. Result: The 3D isotropic T 2 -weighted sequence resulted in the highest signal-to-noise ratio SNR and lowest non-uniformity NU among the sequences in the phantom study.
Conclusion: A 3D T 2 weighted sequence is superior to conventional 2D sequences for the delineation of intradural nerve rootlets and neural foramina and is less affected by CSF flow artefacts. Sax, S.
Each image contributes unique information. SD-weighted images optimally display anatomy and often best highlight pathology. T1-weighted images are critical in assessing cerebral hemorrhages. All three types of ''weighted'' images are necessary to optimally display anatomy and fully characterize a lesion. Computerized calculations and simulations suggest that no other combination of pulse sequences yields equal information for a given examination time.
High-field magnetization measurements at 4. An antiferromagnetic ground state of U 2 Pt 2 Sn is corroborated by a metamagnetic transition at 22 T with very small hysteresis going up and down with field. U 2 Co 2 Sn and U 2 Ir 2 Sn show no metamagnetic transition up to 57 T which is in agreement with the non-magnetic ground state of these compounds.
In all cases, the maximum applied field is not sufficient to achieve saturation. The short-pulse measurements presented here are compared with previous results obtained in quasi-static fields up to 35 T. To evaluate diagnostic precision of the axial TSE- T 2 sequence in the diagnosis of choledocholithiasis. Retrospective analysis of all those MR cholangiography studies performed in our center between January and June which were later subjected to conventional cholangiography intraoperative as a golden standard.
A total of 39 patients was studied. Without having been informed as to the cholangiography result, two radiologists independently analyzed this sequence in order to determine the presence of choledocholithiasis. Their results were latter compared with those of the conventional cholangiography.
The sensitivity, specificity and agreement between results were all calculated. The axial sequence TSE- T 2 is reliable for choledocholithiasis diagnosis. Author 9 refs. Soils are natural porous media of highest importance for food production and sustainment of water resources. For these functions, prominent properties are their ability of water retainment and transport, which are mainly controlled by pore size distribution.
The latter is related to NMR relaxation times of water molecules, of which the longitudinal relaxation time can be determined non-invasively by fast-field cycling relaxometry FFC and both are obtainable by inversion recovery - multi-echo- imaging IR -MEMS methods. The advantage of the FFC method is the determination of the field dependent dispersion of the spin-lattice relaxation rate, whereas MRI at high field is capable of yielding spatially resolved T1 and T 2 times.
Kaldenkirchen soil shows relatively broad bimodal distribution functions D T1 which shift to higher relaxation rates with increasing relaxation field. The distribution of T1 corresponds well to that obtained by FFC. Agreement between T 2 and haste sequences in the evaluation of thoracolumbar intervertebral disc disease in dogs.
The purpose of this study was to compare half-Fourier-acquisition single-shot turbo spin-echo HASTE and T 2 -weighted T 2 -W sequences in dogs with thoracolumbar disc extrusion.
MRI studies in 60 dogs individual intervertebral disc spaces were evaluated. Agreement between T 2 -W and HASTE sequences was assessed for two criteria: presence of an extradural lesion and treatment recommendation. HASTE was in agreement in Acquisition of a HASTE sequence in addition to conventional sequences may be beneficial in determining the severity of spinal cord compression in some cases when evaluating the canine spine. Bruine, Francisca T. Six infants with post-hemorrhagic ventricular dilatation detected by US in the neonatal period were excluded.
Infants were seen for follow-up at 2 years. Univariate and regression analysis assessed the relation between presence and location of hemosiderin, white matter injury and neurodevelopmental outcome.
The magnetic resonance imaging MRI sequences that obtain all the data using a sole excitation pulse of 90 degree centigrade, filling the K space in a single repetition time TR is known as snap shot or single shot SS. A comparison with the conventional T 2 -weighted spin-echo sequence ]. T 2 -weighted spin-echo imaging is the standard screening procedure in MR imaging of the neurocranium. We evaluated fast spin-echo T 2 -weighted imaging TT2 of the neurocranium in comparison to conventional spin-echo T 2 -weighted imaging T 2.
Signal-to-noise and contrast-to-noise ratio of normal brain tissues basal ganglia, grey and white matter, CSF fluid and different pathologies were calculated. Signal-to-noise ratio and contrast-to-noise ratio were significantly higher in TT2 than in T 2 with the exception of gray-to-white matter contrast. Tissues with increased content of water protons mobile protons showed the highest contrast to surrounding tissues. The increased signal intensity of fat must be given due attention in fatty lesions.
Because the contrast-to-noise ratio between white matter and basal ganglia is less in TT2, Parkinson patients have to be examined by conventional T 2.
If these limitations are taken into account, fast spin-echo T 2 -weighted imaging is well appropriate for MR imaging of the neurocranium, resulting in heavy T 2 -weighting achieved in a short acquisition time. Although magnetic resonance imaging MRI of the fetus is considered an established adjunct to fetal ultrasound, stacks of images alone cannot provide an overall impression of the fetus.
The present study evaluates the use of thick-slab T 2 -weighted MR images to obtain a three-dimensional impression of the fetus using MRI. A thick-slab T 2 -weighted sequence was added to the routine protocol in fetal MRIs obtained for various indications 19th to 37th gestational weeks on a 1.
Slice thickness adapted to fetal size and uterine geometry varied between 25 and 50 mm, as did the field of view mm. Acquisition of one image took less than 1 s. The pictorial essay shows that these images visualize fetal anatomy in a more comprehensive way than is possible with a series of mm thick slices.
These thick-slab images facilitate the assessment of the whole fetus, fetal proportions, surface structures, and extremities. Fetal pathology may be captured in one image. Thick-slab T 2 -weighted images provide additional information that cannot be gathered from a series of images and are considered a valuable adjunct to conventional 2D MR images. Brugger, Peter C. E-mail: peter. Therefore, two new measurement techniques were developed that acquire a smoother k-space than generic multi shot echo planar imaging sequences.
One is based on the principle of echo train shifting, the other on the reversed gradient method. Simulations and phantom measurements demonstrate that echo train shifting works properly and reduces artifacts in multi shot echo planar imaging.
For maximum SNR-efficiency this technique was further improved by adding a second contrast. Both contrasts can be acquired within a prolongation in measurement time by a factor of 1. Furthermore it is demonstrated that the reversed gradient method remarkably reduces artifacts caused by a discontinuous k-space weighting.
The value of fat-suppressed T 2 or STIR sequences in distinguishing lipoma from well-differentiated liposarcoma.
Galant, J. Peset, Valencia Spain ; Saez, F. The objective of this study was to evaluate the diagnostic value of fat-suppressed T 2 -weighted FS- T 2 images or short tau inversion recovery STIR imaging in distinguishing lipoma from lipoma-like subtype of well-differentiated liposarcoma. Fourteen lipomas Overdiagnoses of well-differentiated liposarcoma can occur due to the presence of non-lipomatous areas within lipomas.
Cardiac T 2 -mapping using a fast gradient echo spin echo sequence - first in vitro and in vivo experience. Background: The aim of this study was the evaluation of a fast Gradient Spin Echo Technique GraSE for cardiac T 2 -mapping, combining a robust estimation of T 2 relaxation times with short acquisition times. The sequence was compared against two previously introduced T 2 -mapping techniques in a phantom and in vivo.
Methods: Phantom experiments were performed at 1. Child dermoid cyst mimicking a craniopharyngioma: the benefit of MRI T 2 -weighted diffusion sequence. Brain dermoid cysts are very rare lesions.
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