Biomedical subjects
Publications and source records attributed to R W Holt.
A 17-year-old girl with cholelithiasis associated with mitral valve replacement four years earlier is presented. The potential for the development of cholelithiasis after cardiac valve replacement in children and adolescents is emphasized.
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A novel method for estimating the susceptibility of an object by using the magnetic resonance (MR) imaging field distortions in an external-reference water bath next to the object is described. The field measurement was obtained with a phase reconstruction from a gradient-echo acquisition. A field model of an arbitrary object in a static magnetic field was discretely calculated from geometry determined from the magnitude reconstruction. Least-squares estimation yields the susceptibility of the object. Required (and proven) assumptions include validity of superposition, object homogeneity, negligible higher-order field terms, field-model accuracy, geometric-model accuracy, and correlation of gradient-echo phase to field distortion. MR susceptometry estimation of phantoms yielded susceptibility estimates that correlated well with known values (r > .9975). This MR susceptometry method is a first step toward quantitation of iron levels through MR imaging phase information in patients with iron overload.
Peutz-Jeghers syndrome is a familial disease characterized by mucocutaneous pigmentation and intestinal polyposis. Small-intestinal intussusception is a common complication. Preservation otion technique to prevent intussusception is described.
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The use of the Cordis shunt tunneler has simplified the creation of the subcutaneous tunnel for chronic venous access catheters. The tunneling maneuver is rapid, is associated with little patient discomfort, and in a series of 25 consecutive patients has not been associated with hematoma formation.
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