International Urology and Nephrology 8 (1), pp. 17--26 (1976)

Four-Channel Radioisotope Renography* (Complex Investigations) L. SZOMOR,** F. BALOGH, P. ZILLICH*** (With the technical assistance of E. Sztile jr.) Department of Urology, University Medical School, P6cs~ and * * * M E D I C O R Works, Budapest (Received December 9, 1972)

A n attempt has been made at a fuller utilization of the information content of 13q-Hippurate in four-channel renography, recording the activities over the kidneys, heart and bladder. The four-channel system was supplemented with a digital scaler, which enabled also the volume of residual urine to be determined after renography. In functional disorder of the upper outflow tract, the examinations were performed in b o t h supine and sitting positions. The expanded procedure has rendered the familiar method of renography more valuable and has often given essential diagnostic help when used in combination with other clinical data.

After thyroid studies, radiorenography, a routine diagnostic procedure, is the second commonest isotope examination. Most of those who have been employing it over the past seventeen years use only two nuclear "channels", as indicated in the original description. By the term channel is here meant a system of scintillation probes with rate meters and recorders. The amount of information obtainable during the whole renal transit of lalI-Hippurate is, however, larger than what can be utilized by the usual twochannel procedure. The character of the three-phase renogram depends on the blood supply of the kidney, the ability of the tubular cells to take up and secrete radioactive Hippurate as well as on whether the urine outflow is normal or not. In addition, the curve contains the activity of the Hippurate present in non-renal tissues and vessels which are caught in the field of view of the radiation detector, and also the changes of this activity. The contribution of the individual "Hippurate compartments" to the total activity recorded varies with time [22]. Corresponding to the aim of the examination, what is to be measured is the activity of the kidney and, within this, the contribution of the renal parenchyma and the renal cavities is of primary importance. * Read at the annual meeting of the National Society of Hungarian Urologists and Nephrologists, at Szeksz~ird, Hungary, June 1972. ** Current address: Department of Urology and Nephrology, Central Hospital of Borsod County, 3501 Miskolc, Szentp6teri kapu, Hungary. 2

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Szomor et al.: Four-channel radioisotope renography

Thus if only renal activity is to be determined (excluding the activity of non-renal tissue), background activity has to be subtracted from the renogram. It is the activity measured over the right lung and that over the chest which best correspond to the tissue background of an empty kidney bed and the lumbar region, respectively [I 1, 20, 24, 26]. However, several authors measure activity over the heart mainly for circulatory reasons [3-5, 9, 12, 18, 19]. Actually, the tissue background curve corresponds to the Hippurate clearance curve. The recording of background activity renders the method a three-channel procedure. Simultaneous administration of radioactive iodoalbumin (R.I.H.S.A.) permits also the activity of the intravascular compartment seen by the detector to be measured. The curve and pulse values so obtained can be subtracted section by section [8], however, procedures have also been elaborated for automatic subtraction. Using a digital, and later an analogue computer, Brown and Britton [3-5] developed and apply a method for automatic background subtraction, which they term "computer assisted blood background subtraction" (C.A.B.B.S.). The same result was achieved by Takd et al. [21] without a computer. The "'cleaned" renogram obtained by automatic background subtraction is undoubtedly more informative but very expensive. However, in practice a simple comparison of the clearance curve with the renogram, e.g. by placing one on top of the other, will also suffice. When the activity of the bladder is also to be recorded the procedure can be supplemented with one more channel. In connection with the value of the supplementary channel three factors are mentioned in the literature: (a) in low urine flow rate in the upper urinary tract it can characterize this condition itself and also filling of the bladder [17]; (b) it is suitable for demonstrating vesicorenal or vesicoureteral reflux [1, 10]; (c) it can differentiate distortions of the renogram which originate in mobile kidneys from those due to real functional disorder of urinary flow [20]. It is only by adding the cystogram curve that some authors make the procedure a three-channel one [1, 10, 14, 17, 20]; others use four channels by supplementing it with background and bladder curves [3 5, 9, 12, 18, 23, 24]. The radioactive urine accumulated in the bladder provides a further possibility for uroflowmetry [25]. Measurement of radioactivity of urine in the bladder before and after urination and volume of urine voided permits the volume of residual urine to be determined without catheterization, for which a method has been described by Claunch et al. [6] and Mulrow et al. [13], nearly simultaneously. The radioactivities measured over the bladder before and after urination being proportional to the volume of urine present in the bladder, the volume of residual urine can be calculated from the former values and from the volume of urine voided simply by means of the rule of three (see Fig. 9). The procedure is considered accurate by many authors [2, 6, 7, 13, 15, 25]. Bladder activity can be determined from both digital [2, 25] and analogue [6, 7, 13, 15, 16] values. International

Urology and Nephrology 8, 1976.

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The dependence of renal outflow on bodily posture, and the disorders of outflow are common knowledge. The sensitive method of renography, in its two-, three-, or four-channel versions, deserves special attention in the demonstration of these alterations. Most authors perform renography with the patient sitting [24], others in supine position [1], possibly half-sitting [5], and even comparative examinations are carried out [23].

Method

On the basis of the above censiderations, the literature data and their own experiences, the authors have developed the following procedure. Four-channel examinations were performed with the administration of 0.5 ILCi/kg b.w. of l'~iI-Hippurate. Two Hungarian-made, two-channel "Radiorenographs" type MB 7104 were used. Radiation detectors type ND-131, containing NaI(T1) cubic crystals 40 mm in diameter, were applied in " G a m m a " collimators type NZ-136 with an asymmetrical diaphragm. A special examination table, designed and constructed by one of the authors, which allowed examinations in both sitting and supine positions, was employed. One detector was placed over each kidney, one over the heart and a fourth over the urinary bladder. A time constant of 3 sec and fivefold amplification were used. Our energy-selective apparatus permitted both integral and differential energy discrimination. With the parameters chosen, the respective activities over the kidneys and heart were under 500 imp/sec, while over the bladder a maximum of 2000 imp/sec was occasionally recorded, in the case of good renal function. Paper speed was 5 ram/rain. No automatic background subtraction or R.I.H.S.A. was used because of the exceedingly large amount of work and the expenses they demand. Evaluation by placing the two curves on top of each other proved to be satisfactory for clinical routine. However, the authors do not regard automatic background subtraction as superfluous, in fact they intend to use it themselves. With the aid of a four-way switch the pulses delivered by the detector of any of the four channels could also be sent to a digital scaler type G a m m a N K 108 (see Fig. 10). Determination of the residual urine was performed by means of this scaler as follows. After 30 rain renography, the patient was allowed to get up and walk at will. Re-examination followed at 60, 90 or 120 min after the intravenous administration of Hippurate, when a few minutes' recording revealed if the cystogram had reached the so-called plateau phase of filling. This was followed by two 1-min measurements each over the bladder and over the heart. The result of the latter was considered tissue background and subtracted from the value measured over the bladder. Then the patient emptied the bladder, and the volume of the urine voided was determined in a measuring tube. Thereafter, a new measurement was made over the bladder, the background being subtracted also in this case. The volume of the residual urine was calculated by 2*

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Szomor et al.: Four-channel radioisotope renography

substituting in the known formula the pulse number obtained after subtraction of the background, as well as the volume of urine voided. Although many authors had found good agreement between the values obtained by the residual test and those by control catheterization, as a check the latter procedure was considered indispensable during the development of the method. The calculated values were checked by determination of the residual urine by catheterization in twenty patients. A maximum difference of -+-10 ml was found between the calculated values and those obtained by catheterization. The control examinations by catheterization were performed on subjects in whom catheterization or endoscopic examination was necessary also for some other reason. Discussion

In the case of a so-called "normal" renographic curve, the background or cystographic curves, i.e. the three- or four-channel examinations, are not of great importance. However, in clinical practice such a normal curve will occur only relatively rarely (Fig. 1). As is seen in Fig. 2, the use of Hippurate, as a bolus, results in a somewhat higher activity over the heart in the first minutes after administration. Later, owing to the uniform distribution of Hippurate in the circulating blood, the activity practically corresponds to that recorded over a nephrectomized, " e m p t y " lumbar region.

Fig. 1 International Urology and Nephrology 8, 1976

Fig. 2

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Szomor et al.: Four-channel radioisotope renography

Fig. 3

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Fig. 4

Fig. 3. S. P. male, aged 17 years. Bilateral renal tuberculosis; left kidney completely destroyed ("putty"). Distorted renogram, prolonged renal transit time, excretion maximum at 8 rain. Over the left kidney there is only a background curve which, after 2 min, is identical with the clearance curve used as background proper. The bladder curve is a nearly exact mirror image of the renogram taken over the functioning right kidney Fig. 4. M. Sz. male, aged 43 years, after acute left pyelonephritis. In the first minute the placing of the detector over each kidney was corrected in accordance with the situation of the respective kidney. Right: normal curve; left: periodic, irregular outflow mirrored in the cystogram. F r o m min 17 on, the bladder curve was recorded in a higher measuring range

Fig. 1. F. B. male, aged 22 years. Chronic prostatitis. Normal renogram on both sides. The "spike" on the curve, recorded over the heart after the injection of Hippurate as a bolus, is caused by the Hippurate passing in front of the detector. Complete mixing is achieved in about 1 rain. F r o m that time on, the curve can be regarded as representative of the background. A steep rise is seen on the bladder curve. The short time constant used permits the assumption that the short delays in time to peak on the bladder curve at 6, 7 and 8 minutes might correspond to discontinuities in ureteric function. F r o m minutes 12 and 25 on, the bladder curve was recorded in higher measuring ranges (1000 and 2000 c/s, respectively) Fig. 2. A. P. male, aged 52 years, left nephrectomy for apostematous pyelonephritis. The renogram of the right kidney is normal. The curves recorded over the empty left kidney bed and the heart are nearly identical from minutes 3-4 on. The cystogram is a nearly exact mirror image of Phase III of the renogram recorded over the solitary right kidney International Urology and Nephrology 8, 1976

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Szomor et al.: Four-channel radioisotope reno#raphy

The most i m p o r t a n t field of application of the clearance or b a c k g r o u n d curve recorded over the heart proved to be cases of strongly impaired function of one kidney, a n d uncharacteristic renograms, sometimes referred to as "isosthenuric". Exact localization taken for granted, identity of the curve recorded over the heart, at 3 minutes, with that over the kidney in question is sufficient for determining the type of b a c k g r o u n d , i.e. the absence of f u n c t i o n i n g renal tissue. T h e m e t h o d is of no less importance in the exact d e t e r m i n a t i o n of the extent of functional asymmetry in bilaterally strongly impaired renal function. On such occasions it can be helpful in the indication of surgery (see Fig. 5). A cystographic curve recorded over the bladder is not characteristic. Theoretically, it would correspond to a graphic representation of chromoscopy, which was widely used earlier. I n most cases, it can be divided into three phases.

Fig. 5

Fig. 6

Fig. 5. Gy. N. female, aged 45 years, after left nephrotomy. Bilateral staghorn calculi. No urinary secretion was demonstrated by infusion urography. The patient had moderate azotaemia. The curve recorded over the operated left kidney is practically identical with the background curve. The renogram of the right side is compatible with obstruction to outflow. Up to rain 22 the cystogram corresponds to the background and it is only then that it exhibits a minimal elevation. The extremely prolonged transit time of the right kidney, solitary from the point of view of function, called for surgery Fig. 6. J. R. male, aged 69 years, benign prostatic hypertrophy with a moderate volume of residual urine. Both renograms are distorted, with periodic disordered outflow on both sides, which is mirrored in the bladder curve International Urology and Nephrology 8, 1976

S z o m o r et al. : Four-channel radioisotope renography

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Phase I: Background curve for 2 3 rain, i.e. during Phases I and I! of the renogram. Phase H: After the peak of the renogram, Phase If of the cystographic curve shows a nearly logarithmic rise - a mirror image of Phase III of the renogram in a normal case. The steepness of the rise is a function of the minute diureses of the individual kidney, as well as of total renal function.

Fig. 7. I. R. female, aged 20 years. Left chronic pyelonephritis. Decreased excretion on right, with periodic disordered outflow on b o t h sides, which can easily be followed on the bladder curve. F r o m min 11 a n d 18 on, the bladder curve was recorded in higher measuring ranges (1000 and 2000 c/s respectively)

Phase III: After nearly complete clearance of the Hippurate, the cystogram shows the character of almost a plateau. This is the time for a residual test to be performed. If Phase III of a renogram of one or both sides is abnormal, so is the cystogram. If the latter is like a mirror image of the former (Figs 4, 6, 7), it definitely speaks against the possibility of a technical error or disappearance of a mobile kidney from the field of view of the radiation detector. However, a cystogram strikingly flattened out, even in the case of isosthenuria, is a sign of severe stagnation in the upper urinary tract which calls for urgent repair rather than a sign of low minute diuresis (Fig. 5). The examinations in various bodily postures were considered necessary not only in renal ptosis but also in any distortion of Phase Ill that did not correspond International Urology and Nephrology 8, 1976

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S z o m o r et al. : Four-channel radioisotope renography

to the morphological picture (Fig. 8a, b). O u r work in that direction will be the subject of a separate c o m m u n i c a t i o n . D e t e r m i n a t i o n of the volume of residual urine without catheterization is a m o d e r n d e m a n d , which is met by our method. Because of its accuracy a n d simplicity we have been using it extensively. It can be performed also indepen-

a

b

Fig. 8a. V. V. male, aged 44 years, after Hynes-Anderson's right pyeloplasty. The examination was performed in supine position. Distorted renogram on both sides and especially on the left. b. The same patient in sitting position. Normal curves on both sides. Theexamination performed in the two positions showed disorder of urine flow observed in supine position to be of functional origin

A,cpm

X,ml

B,cpm

Fig. 9. The principle of determining residual urine volume by the isotope method without catheterization International Urology and Nephrology 8, 1976

Szomor et al. : Four-channel radioisotope renography

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dently of renography, the necessary equipment being only a scintillation probe and a scaler. It is, however, more economical to combine it with renography. More than 1800 complex four-channel examinations have been performed with the method outlined above in the Department of Urology of the University Scint deL

Rodionephrogroph

-o

Digital scoIer

/ Fig. 10. Block diagram of the four-channel system described. By means of a four-way switch the pulses delivered by each individual detector are also sent to a digital scaler

Medical School of Pdcs since the beginning of 1971. In our experience the expanded procedure, as described above, has proved useful and has considerably increased the diagnostic value of renography.

References 1. Asano, M.: A b n o r m a l hydrodynamics during vesico-ureteral regurgitation. J. Urol. 104, 402 (1970). 2. Blaufox, M. Donald: Evaluation of renal function and disease with radionuclides. In: Progress in Nuclear Medicine, Vol. 2. S. Karger, Basel 1972. 3. Britton, K. E., Brown, N. J. G. : The use of the radioactive renogram in the reticuloses. Brit. J. Radiol. 42, 34 (1969). 4. Brown, N. J. G., Britton, K. E.: The renogram and its quantitation. Brit. g. Urol. 41, Suppl. 15 (1969). 5. Brown, N. J. G., Britton, K. E.: A new system of renography. Bio-Med. Eng. 4, 268 (1969). 6. Claunch, B. C., Barnes, W. T., O'Hara, V.: Determination of the volume of residual urine using diodrast 131I. J. Urol. 86, 551 (1961). 7. Epstein, I. M., Glaiser, Ju. Ja. : Opredelenie ostatotchnoi motchi radioisotopnym methodom. Urol. i Nefrol. (Moskva) 6, 19 (1965). 8. Gazs6, J., Somogyi, Gy.: A v6ractivit~is levonfisfival k~sz~ilt radiorenogramm. Orv. Hetil. 111, 1825 (1970). 9. Harvey, R. F., Keeling, D. H.: Investigation of ureteric function by isotope renography. Lancet 847 (1969). 10. Kapuscinski, A.: Isotopen-Nephrozystographie als Methode zur Aufdeckung des H a r n blasen-Ureter-Reflux. Rad. diagn. 9, 53 (1968). 11. Kooman, A., A1, N., van Hinsbergh, W. C. M., van Stekelenburg, L. H. M., Truyens, J. H. J., van Vals, G. H.: Renogram and clinician. Urol. int. 24, 37 (1969). 12. Motchalova, T. P.: Radioisotopnie metody issledovania v diagnostice tuberculesa motchevoi systemy. Probl. Tuberk. (Moskva) 48, 11 (1970). International Urology and Nephrology 8, 1976

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13. Mulrow, P. J., Huvos, A., Buchanan, D. L.: Measurement of residual urine with l:*lIlabeled Diodrast. J. Lab. Clin. Med. 57, 109 (1961). 14. Pytel, A. Ja., Bagdasarov, M. B.: Radioisotopnaja diagnostica chirurgichescih zabolevani potschek. Ajastan, Jerevan 1970. 15. Rosenthall, L.: Residual urine determination by roentgenographic and isotope means. Radiology 80, 454 (1963). 16. Shand, D. G., MacKenzie, J. C., Gatell, W. R., Jocelyn Cato: Estimation of residual urine volume with 13q-Hippuran. Brit. J. Urol. 40, 196 (1968). 17. Sigman, E. M., Kutzman, N., Brown, B.: Serial radioisotope renocystography in acute renal failure following retrograde pyelography. J. Urol. 90, 28 (1963). 18. Soskine, A. M., Motchalova, T. P., Chapiro, A. L.: Znatsenie radioisotopnoi renographii v diagnostice tuberculesa motschevoi systemi. Probl. Tuberk. (Moskva) 45, 710 (1967). 19. Spesibcheva, B. G., Zolotarev, I. I., Gleiser, Ju. Ja., Schlevcov, B. A.: Radioisotopnoe scennirovanie i renographia pri necotoryh zabolevanija potshek. Ther. Arch. (Moskva) 39, 53 (1967). 20. Szomor, L.: Clinical value of radiorenography based on 1000 examinations. Lecture held at the Congr. Urol. et Nephrol., Budapest 1968. 21. Tak6, J., Krasznai, I., B~nos, Cs., Pog~iny, Gy., Kapus, I.: Automatikus berendez6s a v6ractivit~.s kikfisz6b616s~vel k6szitett radiorenographi~ihoz. Orv. Hetil. 113, 1669 (1972). 22. Vax, S. H., McDonald, D. F.: Analysis of the *a*I sodium o-iodohipputare renogram. J A M A 179, 140 (1962). 23. Winkel, K.: Nierendiagnostik mit Radioisotopen. Thieme Verlag, Stuttgart 1964. 24. Winter, C. C.: Radioisotope Renography. Williams and Wilkins Co., Baltimore 1963. 25. Winter, C. C.: Radioisotope uroflowmetry and bladder residual test. Trans. Am. Ass. Gen.-urin. Sur#. 55, 50 (1963). 26. Winter, C. C.: Radioisotope renography -- the first decade. Proc. Roy. Soc. Med. 58, 351 (1965).

International Urology and Nephrotogy 8, 1976

Four-channel radioisotope renography (complex investigations).

International Urology and Nephrology 8 (1), pp. 17--26 (1976) Four-Channel Radioisotope Renography* (Complex Investigations) L. SZOMOR,** F. BALOGH,...
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