Experimental Study on Visualization of Renal Parenchyma by Scintiscanning with Hg203 Neohydrin to Dog

Cho, Kyu Wan; Kim, Kee Soo

Abstract

The detection of renal disorders now involves a series of complicated diagnostic procedure such as radiologic pyelography, function studies in laboratory and others These add up to a painful, expensive, and time consuming experience for the patient, others may be spared the discomfort of unnecessary. Consequently, the development of methods for preliminary screening of patients is significant both with regard to the diagnostic information obtained and to the selection of those patients requiring complete urologic work up. In particular, a reliable screening test is important in establishing or ruling out renal pathology as an underlying factor in hypertension the finding of a disorder of one kidney in the hypertensive patient may be at indication for nephrectomy or other surgical measures of renal artery. A positive preliminary investigation warrants precise diagnosis by aortography and confirmation by individual renal clearance tests. Finally the primary objective of the screening test is the restriction of more exacting procedures such as aortography with its inherent risk of serious complications to the preoperative evaluation of a demonstrated lesions. The visualization of an internal structure by determining the spatial distribution of a gamma radiation-emitting isotope was started in 1950 when Cassen and his associates utilized newly developed scintillation counters to print mechanically the spatial distribution of radioactive iodine in the thyroid gland. Visual and functional informations referable to each kidney separately may be obtained by radioisotopes and tracer or by scanning techniques rapidly and without trauma. The renogram or tracing of the renal uptake and excretion of a labeled contrast medium is a clinically useful measure of renal vascularity, tubular cell function, and the patency of the upper urinary passage, and especially valuable as a screening test for the hypertensive patient with suspected unilateral disease of the kidney. Similarly, scanning images are achieving an important place in medical diagnosis of irregularities effecting the kidneys and other specific organs. Radioactive contrast media, such as I131 labeled diodrast, miokon, Urokon, or hippuran have been widely used for renal function studies. They are entirety unsatisfactory, however, for renal scintillation scanning because they are rapidly excreted by the kidneys without retention in the renal parenchyma in contrast but mercurial diuretics labeled with radioactive mercury are concentrated to a high degree in the renal tubular cells, chiefly in the cortex, prior to their appearance in the urine (Borghgraef 1956.MaAfee and Wagner 1960). Following the report of these letter writers, scintillation scanning of the kidney after the intravenous injection of Hg Neohydrin have been widely used in urological clinics for preliminary screening method of renal disease such as delineating the parenchyma of the kidney and space-occupying lesions by Krevitz, Berk, and others(Reley, Blahd, Mins, Morgan, Kuhl, Bender, Simmons, Blau, Kim) and remained several problems which is anticipated to improvements in resolution for further using of renal scan. The main purposes of this experimental study were: 1) to learn at which period of time it is best to visualize the renal parenchyma following the intravenous administration of Hg Neohydrin, 2) to learn the minimal detectable size of space-occupying lesion within the kidney phantom, and 3) to compare the renal scan with aortography and pyelography on various period of hydronephrosis for visualization of renal parenchyma, 4) to compare the renal scan with aortography on various degree of narrowing of the renal artery for visualization of renal parenchyma.
MATERIALS AND METHODS
These experiments have been performed on 17 normal adult mongrel dogs anesthetized with intravenous injection of sodium amycal. Ofthese 3 dogs were used for determining the optimal time of visualization of the renal parenchyma. 8 dogs for the visualization of the parenchyma of hydronephrotic kidneys as created by partial ligation of the left ureter for the period of 1. 2. 3 and 4 weeks as devided in 4 groups, and 6 dogs were used for the visualization of the narrowed renal artery produced by partial obstruction to various degrees. A wax phantom of the kidney was utilized for the study of detectable minimal size of the intrarenal space occupying lesion, the phantom measures 12.5 X 6.2 X 3.5cm. All animals underwent renal scintiacan received 80 microcuri of Hg neohydrin intravenously, they were placed in a prone position and the study was carried out using a Nuclear-Chicago dual scanner with a 62-hole coarse focusing collimator containing a 3x3 inch sodium iodide crystal, the collimator was passed back and forth over the target are at a rate of 12-15cm, per minute. The scan usually required 30 minutes for complete of scan. The pyelography was performed in retrograde way with 30% diodrast injected through ureteral catheter and the amount of dye injected was adjusted to replace the urine from renal pelvis. The aortography was performed by transfemoral arterial catheterization technique as described by Seldinge.
RESULTS
1. The optimal opacification period of renal parenchyma after injection of Hg 203 neohydrin was found to range from 1 to 6 hours 2. By kidney phantom study it was demonstrated that the space-occupying lesion measuring 2cm. in diameter can not be detected on scan. While the lesion measuring 3cm, or more can be successfully visualized. 3. The effect of partial obstruction of the ureter upon the renal scintiscan for visualization of renal parenchyma was not. dependable, the renal scintiscan continued to appear up to at least the 2 weeks after partial obstruction of ureter whereas the retrogredepyelography and aortography showed the definite picture of hydronephrosis to various degree. 4. The renal scan is inconsistent in many instances of renal artery stenosis, the scan showed a diminished concentration of mercury in the kidney with stenotic main renal artery and complete failure of visualization of the renal substance in cases with completely obstructed renal artery. 5. It is possible to demonstrate the value and usefulness of renal scan of Hg neohydrin as a routine preliminary screening test for renal pathology, the alteration of the concentration of the mercury can might be expected to give additional information.