The ureteral pressure/flow perfusion study has lately been repopularized and its use demonstrated in many forms of suspected obstructive uropathy. The present study was undertaken to compare the ureteral pressure/flow perfusion study with a radioisotopic method of investigating ureteral obstruction. The 2 methods were evaluated with a mongrel canine laboratory model. Both diagnostic modalities were employed concomitantly on intact renoureteral units; first with the ureter unobstructed, then after submission to varying degrees of ureteral occlusion. Analysis of data from these studies shows that the curve pattern produced by the computer generated 99mTc-DTPA renogram is as accurate as ureteral pressure/flow perfusion study in determining the presence and degree of ureteral obstruction.

Animals↗

PubMed1982

A simplified in vivo autoradiographic strategy for the determination of regional cerebral blood flow by positron emission tomography: theoretical considerations and validation studies in the rat.

A simplified mathematical model is described for the measurement of regional cerebral blood flow by positron emission tomography in man, based on a modification of the autoradiographic strategy originally developed for experimental animal studies. A modified ramp intravenous infusion of radiolabeled tracer is used; this results in a monotonically increasing curvilinear arterial activity curve that may be accurately described by a polynomial of low degree (= zeta). Integrated cranial activity CB is measured in regions of interest during the latter portion of the tracer infusion period (times T1 to T2). It is shown that (See formula: text) where each of the terms A chi is a readily evaluated function of the blood flow rate constant kappa, the brain:blood partition coefficient for the tracer, the cranial activity integration limits T1 and T2, the coefficients of the polynomial describing the arterial curve, and an iteration factor n that is chosen to yield the desired degree of precision. This relationship permits generation of a table of CB vs. kappa, thus facilitating on-line computer solution for blood flow. This in vivo autoradiographic paradigm was validated in a series of rats by comparing it to the classical autoradiographic strategy developed by Kety and associates. Excellent agreement was demonstrated between blood flow values obtained by the two methods: CBF in vivo = CBF classical X 0.99 - 0.02 (units in ml g-1 min-1; correlation coefficient r = 0.966).

Animals↗

PubMed1982

A microtechnique for radioisotopic determination of glomerular filtration rate in infants and children.

Our experience with a microtechnique using 99mTc-DTPA for determination of glomerular filtraton rate in 172 children is presented. It is a simple finger-stick method carried out in a four-hour time period by trained nuclear medical personnel. The procedure meets all criteria for precise measurement of glomerular filtration rate, and the radiation dose is low. Proof of accuracy was obtained by comparison of this technique with concomitant 24-hour urinary creatinine clearance in a subset of children.

Adolescent↗

PubMed1981

Ataxia and deafness in children due to bacterial meningitis.

Eight children with postmeningitis ataxia had detailed neurologic, audiologic, and neurovestibular evaluations. Prolonged fever, prolonged hyponatremia, or septic arthritis occurred in six during hospitalization. Severe to profound sensorineural hearing losses were present in seven of the children. Electronystagmography was abnormal in three of seven children. In seven children, the ataxia has persisted, but steady improvement has been observed during the course of repeated examinations. Hearing should be evaluated routinely in any child who develops meningitis.

Ataxia↗