Comparison of 99mTc complexes for renal imaging.
The distribution of 17 different agents for renal imaging was compared in the rabbit by organ radioassay at 1 hr. Similarly, 99mTc complexes of iron-ascorbate, glucoheptonate (GHA) and 2,3-dimercaptosuccinic acid (DMS), and 203Hg-chlormerodrin were compared in the dog. The distribution of 99mTc-GHA and DMS was assessed in the human by blood and urinary clearance, external renal measurements, and scintillation camera imaging, and compared with older renal radiopharmaceuticals. Radiation dose estimates, based chiefly on human data, were calculated. Technetium-99m-DMS reaches a high concentration in the renal cortex and its urinary excretion rate and blood clearance are slow. It is excellent for imaging the renal parenchyma without activity in pelvocalyceal collecting system. However, it readily oxidizes and must be used within 30 min of preparation. The biologic distribution of 99mTc-GHA is similar to gluconate and iron-ascorbate complex. Its renal concentration is not as great as that of DMS but its blood and urinary clearances are much faster, resulting in lower radiation doses to most organs. Early camera images with this agent usually demonstrate both the renal parenchyma and collecting system. In later images, ther is excellent demonstration of the parenchyma alone, superior to that obtained with 99mTc-Sn-DTPA. It is a very stable complex and may be used for at least 5 hr after preparation. All radioactive renal agents examined to date have a significant concentration in the liver, making an accurate quantitative comparison between the two kidneys difficult. (+info)
Combination of renal and adrenal scanning in the diagnosis of renovascular hypertension: case report.
Superimposition of an adrenal scan on a renal scan revealed a kidney defect not appreciated on the renal scan alone. The defect proved to be ischemia of the upper pole of the kidney. Resection of the lesion alleviated the patient's hypertension. (+info)
THE ROLE OF RADIOISOTOPE RENAL SCANNING IN THE ASSESSMENT OF RENAL DISEASE.
Experience with 500 radio-chlormerodrin renal scans has shown that the technique can detect (1) altered renal function, both focal and generalized, (2) space-occupying kidney lesions, and (3) renal size and disease in some cases in which the blood urea nitrogen is elevated and the excretory urogram inconclusive.The technique is valuable as an adjunct to the intravenous pyelogram since it may discriminate more disease than was thought to be present or may distinguish between anomalous variations in renal outline and calyceal displacement from parenchymal disease. The technique is completely harmless and there are no known contraindications to the test agent, radio-chlormerodrin. (+info)
LOCALIZATION OF ERYTHROCYTE MEMBRANE SULFHYDRYL GROUPS ESSENTIAL FOR GLUCOSE TRANSPORT.
The reactions of three organic mercurial compounds, chlormerodrin, parachloromercuribenzoate (PCMB), and parachloromercuribenzenesulfonate (PCMBS) with intact red blood cells, hemolyzed red cells, hemoglobin solutions, and hemoglobin-free ghosts have been characterized. Both PCMB and PCMBS react with only 2 to 3 sulfhydryl groups per mole of hemoglobin in solution, whereas chlormerodrin reacts with 6 to 7. In hemoglobin-free ghosts, however, all three reagents react with a similar number of sulfhydryl groups, approximately 4 x 10(-17) moles per cell, or about 25 per cent of the total stromal sulfhydryl groups, which react with inorganic mercuric chloride. In the intact cell the membrane imposes a diffusion barrier; chlormerodrin and PCMB penetrate slowly, whereas PCMBS does not. Kinetic studies of chlormerodrin binding to intact cells reveal that the majority of stromal sulfhydryl groups is located inside the diffusion barrier, with only 1 to 1.5 per cent (or 1 to 1,400,000 sites per cell) located outside of this barrier. Reaction of PCMBS with intact cells is limited to this small fraction on the outer membrane surface. All three reagents are capable of inhibiting glucose transport in the red cell. With chlormerodrin and PCMBS it was demonstrated that the inhibition results from interactions with the sulfhydryl groups located on the outer surface of the membrane. (+info)
Computer-assisted static/dynamic renal imaging: a screening test for renovascular hypertension?
Computer-assisted static/dynamic renal imaging with [197Hg] chlormerodrin and [99mTc]pertechnetate was evaluated prospectively as a screening test for renovascular hypertension. Results are reported for 51 patients: 33 with benign essential hypertension and 18 with renovascular hypertension, and for 21 normal controls. All patients underwent renal arteriography. Patients with significant obesity, renal insufficiency, or renoparenchymal disease were excluded from this study. Independent visual analyses of renal gamma images and time-activity transit curves identified 17 of the 18 patients with renovascular hypertension; one study was equivocal. There were five equivocal and three false-positive results in the essential hypertension and normal controls groups. The sensitivity of the method was 94% and the specificity 85%. Since the prevalence of the renovascular subset of hypertension is approximately 5%, the predictive value is only 25%. Inclusion of computer-generated data did not improve this result. Accordingly, this method is not recommended as a primary screening test for renovascular hypertension. (+info)
Brain tumor-scanning agents compared in an animal model.
Sixteen radiopharmaceuticals for brain tumor localization have been compared in a mouse brain tumor model. A rating system is presented for such intercomparison. The rusults indicate that 111-in-chloride injected at pH 1.5 has the most favorable biologic characterisTICS FOR BRAIN TUMOR IMAGING. (+info)
The 131-I ortho-iodohippurate photoscan in human renal allografts.
Nine examples, in seven patients, from a large cadaver renal allograft program, illustrate the value of radio-hippuran photoscans in differentiating causes of post-implant oliguria. Hippuran scans are shown to be more valuable than chlormerodrin scans when renal function is acutely depressed. Hippuran scans aided in the decision to remove kidneys in four cases of severe oliguria and to retain kidneys in two others. In two further examples, extravasation of urine was detected by scanning after radio-hippuran injection when other tests had failed to do so.The technique of radio-hippuran scanning has a place in the differentiation of acute and subacute renal dysfunction and has proved particularly valuable in the early oliguric complications of a cadaver renal transplant program. (+info)
Radiopertechnetate renography with the gamma ray scintillation camera.
Radiopertechnetate renography merits consideration as another intravenous screening procedure for renovascular hypertension. Thus far in our experience it has yielded fewer falsely negative results than the radiohippurate renogram, and it takes less than one minute to complete. Applications of this method to the assessment of renal perfusion in other renal afflictions are described. The examination requires a stationary imaging device interfaced with a storage device and a data processor. It has the advantage of providing a comparison of renal transit of the test agent with its transit through the systemic circulation, e.g. the aorta. (+info)