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Articles 1 - 7 of 7
Full-Text Articles in Biomedical Engineering and Bioengineering
Quantification Of Bronchial Circulation Perfusion In Rats, Christian Wieholt, Robert C. Molthen, Steven Thomas Haworth, David L. Roerig, Christopher A. Dawson, Anne V. Clough
Quantification Of Bronchial Circulation Perfusion In Rats, Christian Wieholt, Robert C. Molthen, Steven Thomas Haworth, David L. Roerig, Christopher A. Dawson, Anne V. Clough
Biomedical Engineering Faculty Research and Publications
The bronchial circulation is thought to be the primary blood supply for pulmonary carcinomas. Thus, we have developed a method for imaging and quantifying changes in perfusion in the rat lung due to development of the bronchial circulation. A dual-modality micro-CT/SPECT system was used to detect change in perfusion in two groups of rats: controls and those with a surgically occluded left pulmonary artery. Both groups were imaged following injections on separate days i) 2mCi of Tc99m labeled macroaggregated albumin (MAA) into the left carotid artery (IA) and ii) a similar injection into the femoral vein (IV). The IA injection …
Post-Acquisition Small-Animal Respiratory Gated Imaging Using Micro Cone-Beam Ct, Jicun Hu, Steven Thomas Haworth, Robert C. Molthen, Christopher A. Dawson
Post-Acquisition Small-Animal Respiratory Gated Imaging Using Micro Cone-Beam Ct, Jicun Hu, Steven Thomas Haworth, Robert C. Molthen, Christopher A. Dawson
Biomedical Engineering Faculty Research and Publications
On many occasions, it is desirable to image lungs in vivo to perform a pulmonary physiology study. Since the lungs are moving, gating with respect to the ventilatory phase has to be performed in order to minimize motion artifacts. Gating can be done in real time, similar to cardiac imaging in clinical applications, however, there are technical problems that have lead us to investigate different approaches. The problems include breath-to-breath inconsistencies in tidal volume, which makes the precise detection of ventilatory phase difficult, and the relatively high ventilation rates seen in small animals (rats and mice have ventilation rates in …
Measuring The Effect Of Airway Pressure On Pulmonary Arterial Diameter In The Intact Rat Lung, Robert C. Molthen, Steven Thomas Haworth, Amy Heinrich, Christopher A. Dawson
Measuring The Effect Of Airway Pressure On Pulmonary Arterial Diameter In The Intact Rat Lung, Robert C. Molthen, Steven Thomas Haworth, Amy Heinrich, Christopher A. Dawson
Biomedical Engineering Faculty Research and Publications
To study the relationship between transpulomnary [sic] pressure (Ptp), intravascular pressure (Pv), and the pulmonary arterial tree structure, morphometric measurements of pulmonary arterial trees were made in intact lungs from Sprague-Dawley rats. Using cone beam micro-CT and techniques we developed for imaging small animal lungs, volumetric CT data were acquired for Ptp from 0 - 12 mmHg and Pv from 5 - 30 mmHg. The diameter, D (measured range approximately 0.08-2.0 mm), vs. pressure, P, relation can be described by D(P) = D(0)(1+ α P), where α is a distensibility coefficient. Unlike studies performed in larger animals, where changes in …
Spect Imaging Of Pulmonary Blood Flow In A Rat, Christian Wieholt, Robert C. Molthen, Roger H. Johnson, Christopher A. Dawson, Anne V. Clough
Spect Imaging Of Pulmonary Blood Flow In A Rat, Christian Wieholt, Robert C. Molthen, Roger H. Johnson, Christopher A. Dawson, Anne V. Clough
Biomedical Engineering Faculty Research and Publications
Small animal imaging is experiencing rapid development due to its importance in providing high-throughput phenotypic data for functional genomics studies. We have developed a single photon emission computed tomography (SPECT) system to image the pulmonary perfusion distribution in the rat. A standard gamma camera, equipped with a pinhole collimator, was used to acquire SPECT projection images at 40 sec/view of the rat thorax following injection of Tc99m labeled albumin that accumulated in the rat's lungs. A voxel-driven, ordered-subset expectation maximization reconstruction was implemented. Following SPECT imaging, the rat was imaged using micro-CT with Feldkamp conebeam reconstruction. The two reconstructed image …
Estimation Of Pulmonary Arterial Volume Changes In The Normal And Hypertensive Fawn-Hooded Rat From 3d Micro-Ct Data, Robert C. Molthen, Christian Wieholt, Steven Thomas Haworth, Christopher A. Dawson
Estimation Of Pulmonary Arterial Volume Changes In The Normal And Hypertensive Fawn-Hooded Rat From 3d Micro-Ct Data, Robert C. Molthen, Christian Wieholt, Steven Thomas Haworth, Christopher A. Dawson
Biomedical Engineering Faculty Research and Publications
In the study of pulmonary vascular remodeling, much can be learned from observing the morphological changes undergone in the pulmonary arteries of the rat lung when exposed to chronic hypoxia or other challenges which elicit a remodeling response. Remodeling effects include thickening of vessel walls, and loss of wall compliance. Morphometric data can be used to localize the hemodynamic and functional consequences. We developed a CT imaging method for measuring the pulmonary arterial tree over a range of pressures in rat lungs. X-ray micro-focal isotropic volumetric imaging of the arterial tree in the intact rat lung provides detailed information on …
Micro-Ct Image-Derived Metrics Quantify Arterial Wall Distensibility Reduction In A Rat Model Of Pulmonary Hypertension, Roger H. Johnson, Kelly L. Karau, Robert C. Molthen, Steven Thomas Haworth, Christopher A. Dawson
Micro-Ct Image-Derived Metrics Quantify Arterial Wall Distensibility Reduction In A Rat Model Of Pulmonary Hypertension, Roger H. Johnson, Kelly L. Karau, Robert C. Molthen, Steven Thomas Haworth, Christopher A. Dawson
Biomedical Engineering Faculty Research and Publications
We developed methods to quantify arterial structural and mechanical properties in excised rat lungs and applied them to investigate the distensibility decrease accompanying chronic hypoxia-induced pulmonary hypertension. Lungs of control and hypertensive (three weeks 11% O2) animals were excised and a contrast agent introduced before micro-CT imaging with a special purpose scanner. For each lung, four 3D image data sets were obtained, each at a different intra-arterial contrast agent pressure. Vessel segment diameters and lengths were measured at all levels in the arterial tree hierarchy, and these data used to generate features sensitive to distensibility changes. Results indicate …
Quantification Of Pulmonary Arterial Wall Distensibility Using Parameters Extracted From Volumetric Micro-Ct Images, Roger H. Johnson, Kelly Lynn Karau, Robert C. Molthen, Christopher A. Dawson
Quantification Of Pulmonary Arterial Wall Distensibility Using Parameters Extracted From Volumetric Micro-Ct Images, Roger H. Johnson, Kelly Lynn Karau, Robert C. Molthen, Christopher A. Dawson
Biomedical Engineering Faculty Research and Publications
Stiffening, or loss of distensibility, of arterial vessel walls is among the manifestations of a number of vascular diseases including pulmonary arterial hypertension. We are attempting to quantify the mechanical properties of vessel walls of the pulmonary arterial tree using parameters derived from high-resolution volumetric x-ray CT images of rat lungs. The pulmonary arterial trees of the excised lungs are filled with a contrast agent. The lungs are imaged with arterial pressures spanning the physiological range. Vessel segment diameters are measured from the inlet to the periphery, and distensibilities calculated from diameters as a function of pressure. The method shows …