PubMed Health⌕ Search

Biomedical subjects

D J McIntyre

Publications and source records attributed to D J McIntyre.

16 recordsLinked to original sources
PubMed1991

The design of practical selective pulses for magnetic resonance imaging and spectroscopy using SPINCALC.

Recently, we introduced a new numerical approach to the design and optimization of NMR selective pulses, which we have christened "SPINCALC" (J. T. Ngo and P. G. Morris, Biochem. Soc. Trans. 14, 1271 (1986); J. T. Ngo and P. G. Morris, Magn. Reson. Med. 5, 217 (1987]. The first practical application of pulses generated by SPINCALC is demonstrated on a standard 0.5-T clinical MRI system. Results are shown for single phase pi pulses suitable both for selective inversion and for selective refocusing. The extension of SPINCALC to multidimensional pulses is illustrated by the design of a two-dimensional pi pulse.

Algorithms↗
PubMed1989

Rational approaches to the design of NMR selective pulses.

The need for NMR selective pulses in magnetic resonance imaging and spectroscopy is reviewed. The shortcomings of the current generation of pulses are discussed and the need for new categories of pulse identified. Strategies for selective pulse design are outlined and two numerical optimization methods, simulated annealing and SPINCALC (a method recently introduced by us: J. T. Ngo and P. G. Morris, Magn. Reson. Med. 5, 217 (1987], are discussed in detail. Their use is illustrated and compared for the design of pi/2 phase-compensated pulses. Both methods require substantial amounts of CPU time, with simulated annealing the more demanding. Unconstrained, simulated annealing also tends to produce pulses with discontinuous waveforms. A crude two-dimensional pulse derived from a low flip angle approximation is illustrated.

Magnetic Resonance Imaging↗
PubMed1986

Pathologic findings of an explanted silicone intraocular lens.

We present a clinicopathological analysis of an explanted STAAR model B silicone intraocular lens (IOL) that was sent to the Center for Intraocular Lens Research for evaluation. Extracapsular cataract extraction (ECCE), using phacoemulsification and insertion of the silicone IOL, had been accomplished through a 3-mm scleral tunnel incision. The IOL was folded and inserted into the ciliary sulcus. Complications, including blurred vision, movement of the IOL within the eye, and glaucoma, eventually led to IOL exchange at three months post-ECCE. After removal of the silicone IOL, a modified J-loop IOL was placed in the intact capsular bag, with subsequent resolution of the increased intraocular pressure and a 20/20 + 3 visual acuity. Pathologic examination of the explanted silicone lens revealed grooves indented into the optic, extensive molding flash, and opalescence of the optic.

Aged↗
PubMed1985

Phototoxicity. The eclipse filter.

In conjunction with ultraviolet filtration and to further minimize the risk of phototoxic retinal damage during anterior segment surgery, the operation microscope has been modified to eliminate on demand all light entering the eye by eclipsing the pupil when the red reflex is not required. Retinal light exposure may be reduced as much as 75%.

Anterior Chamber↗
PubMed1979

IOL terminology.

Explore the source record for details and available documents.

Humans↗
PubMed1979

Comparative endothelial biomicroscopy.

Calibrating comparative endothelial biomicroscopy with a corneal endothelial microscope (Heyer-Schulte Medical Optics), we have obtained clinically useful estimates of endothelial cell density. This simple and inexpensive technique allows rapid examination and evaluation of a large number of endothelial cells across various corneal diameters. It is, however, a clinical rather than investigative procedure and is not intended to replace the quantitative features of endothelial specular photomicrography for scientific studies.

Calibration↗
PubMed1979

The McCannel suture: a bimanual technique.

The bimanual technique utilizing the iris manipulator and a full air bubble allows excellent control of anterior chamber depth and IOL position. It also minimizes the risk of trauma to the underlying lens, posterior capsule or vitreous during placement of iris sutures; and its use may prevent the tragedy of severe endothelial damage during insertion of the McCannel suture.

Humans↗
PubMed1979

Irrigating instruments for intraocular lens implantation.

A series of small instruments to assist with insertion of intraocular lenses and placement of lens fixation sutures has been described. Added to the main function of each, is the capability for infusion of fluid or injection of air and medication.

Anterior Chamber↗
PubMed1978

Save the endothelium.

The health of the corneal endothelium is a critical factor in the final outcome of intraocular surgery . With the advent of intraocular lens implantation, the hazard of inadvertent endothelial trauma is greatly increased. A rigorous technique has been presented which will minimize the risk of such trauma in extracapsular cataract surgery with implantation of Binkhorst type intraocular lenses.

Cornea↗
PubMedDate not supplied

Capsulophine.

Explore the source record for details and available documents.

Cataract Extraction↗