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C A Mistretta

Publications and source records attributed to C A Mistretta.

94 records · Page 6Linked to original sources
PubMedDate not supplied

Coronary blood flow measurement using an angiographic first pass distribution technique: a feasibility study.

Due to the well-documented problems associated with visual interpretation of coronary angiograms, more physiologic means of assessing coronary artery stenosis are being investigated. One physiologic parameter that has been suggested is coronary flow reserve (CFR). A digital subtraction angiographic technique based on first pass distribution analysis (FPA) is proposed as a means of measuring CFR and absolute coronary flow. The theory of the FPA method is first outlined, and the implementation of a preliminary version of the FPA algorithm is described. Experiments verifying the utility of this algorithm for measuring absolute flow through a flow phantom, and through the canine circumflex artery are reported. It was determined that the preliminary FPA algorithm is capable of measuring canine coronary flow ratios (R) with accuracy and precision characteristics meeting or exceeding those reported for the parametric imaging technique (RFPA = 0.933.Rtrue, SEE = 0.16, r = 0.984). Accurate absolute flow (Q) measurements were obtained in all of the phantom experiments (QFPA = 1.054.Qtrue, r = 0.993), and in one of the three dogs that were studied (QFPA = 0.977.Qtrue, r = 0.935). The difficulty encountered in the other two dog experiments is attributed to the effects of system temporal lag, and would likely be corrected through the use of improved cameras. The feasibility of the general FPA method for measuring relative flow is established, and the potential for routine, absolute flow measurement is demonstrated.

Algorithms↗
PubMedDate not supplied

Considerations regarding the application of capillary optics to medical radiography.

The generation of monoenergetic or quasimonoenergetic x-ray spectra has been accomplished by several methods including the use of K-edge filtration, characteristic radiation, crystal monochromators, and multilayer mirrors. In this paper some practical questions are discussed regarding the possibility of obtaining narrow-band spectra using x-ray reflection in glass capillary optics which have been reported recently in connection with the focusing and generation of parallel x-ray beams. Derivation of formulas for double and triple reflection with and without additional K-edge filtration imply that these methods are superior to the use of filtration alone. It is shown that the double reflection scheme is most sensitive to the angular divergence of the beam emanating from the capillary array used to generate the incident parallel beam. Simulations using three reflections predict output spectra which are relatively insensitive to blurring due to angular divergence. A small amount of K-edge filtration in combination with three reflections provides considerable sharpening of the x-ray spectrum. Aside from the spectral selectivity provided by the capillary array, the reduced divergence of the primary transmission may have advantages for scatter rejection in situations where the air gap between the patient and detector is increased by an amount consistent with the resolution requirements of the application. In parallel beam situations, the use of capillary arrays between the patient and detector may also be useful for the rejection of divergent scattered radiation.

Capillary Action↗
PubMedDate not supplied

Intravenous video arteriography of the intracranial vasculature: early experience.

A computerized fluoroscopic apparatus developed by members of the University of Wisconsin Medical Physics Section was used for 12 months to perform intravenous video arteriography. In previous papers, the apparatus was described and its use was illustrated for performing time subtraction intravenous video arteriography of the extracranial carotid arteries, the arteries of the abdomen and extremities, as well as angiocardiography. In this report, the use and current limitations of this technique for evaluation of the intracranial vasculature are described and illustrated.

Aged↗