British Journal of Urology (1992), 69, I 2 6 1 3 I
01992 British Journalof Urology
The F- 15 Diuresis Renogram in Suspected Obstruction of the Upper Urinary Tract S . M. UPSDELL, H. J. TESTA and R. S. LAWSON Departments of Nuclear Medicine and Urology, Manchester Royal Infirmary, Manchester
Summary-The results are presented of the first long-term follow-up study of patients with suspected obstruction of the upper urinary tract investigated by a modified form of diuresis renography (F- 15 renography). The incidence of equivocal results from diuresis renography is significantly reduced by the use of the F- 15 renogram. F- 15 renography provides a reliable assessment of the upper urinary tract in patients with suspected obstruction and is recommended in the investigation of equivocal upper urinary tract dilatation.
Diuresis renography is widely accepted in clinical practice for the investigation of dilated upper urinary tracts. Despite over 12 years’ experience with this technique, however, equivocal results are still obtained in up to 17% of cases (Upsdell et af., 1990). For several years we have been investigating a modified method of diuresis renography in which frusemide is given intravenously 15 min before the radiopharmaceutical (English et af., 1987), a technique which we refer to as F-15 renography. This timing of frusemide has been shown to maximise urinary flow rates (Upsdell et al., 1988; Brown et af., 1992). We report the results of the first longterm follow-up study of 50 patients investigated by this technique and discuss the clinical indications for F-15 diuresis renography. Patients and Methods All patients under the care of a single Department of Urology who were initially investigated for suspected obstruction of the upper urinary tract by both standard and F-15 diuresis renography were entered into the study. Between 1982 and 1987 70 such patients were seen in this department. On follow-up, 2 had died of non-renal causes, 1 was pregnant, 1 declined further follow-up owing to severe arthritis and reduced mobility and 16 had Accepted for publication 3 September 1991
either moved out of the area or defaulted. This left 50 patients, 13 male and 37 female, with 55 symptomatic kidneys available for review. Their ages ranged from 22 to 69 years (mean 40). All patients had suspected obstruction of the upper urinary tract on clinical and/or radiological grounds. All underwent initial assessment by standard gamma camera renography (O’Reilly et al., 1978), followed by F-15 renography in which frusemide is given intravenously in a dose of 0.5 mg/kg bodyweight 15 min beforethe radiopharmaceutical (English et af., 1987). All scans were performed using 231-Hippuran (0.2 MBq/kg body weight) with the patient sitting in front of a gamma camera. The acquired data were analysed using an MDS computer. Four patterns of elimination were identified during the standard diuresis renograms asdescribed by O’Reilly et af. (1978), i.e. unobstructed (type I), obstructed (Type 11), hypotonic (Type IIIa) and equivocal (Type IIIb). In F-15 renography only 3 types of washout curve are identified, namely unobstructed, obstructed and equivocal. The subsequent management of all patients was based on clinical signs and symptoms and the results of the initial F-15 renogram. At the conclusion of the study all patients underwent further clinical, biochemical and renographic assessment. The time between the initial F-15 renogram and the final renographic assessment ranged from 1 to 7 years,
126
SUSPECTED OBSTRUCTION OF T H E UPPER URINARY TRACT
with a mean follow-up of just over 4 years (50 months). Only 4 patients had a follow-up period of less than 24 months. Results Initial renographic assessment and management There were 32 cases of unequivocal washout on standard diuresis renography (9 unobstructed, 19 hypotonic and 4 obstructed). The results of the F15 renogram agreed with the standard diuresis renogram in all 9 unobstructed cases and these patients were all treated conservatively. Of the 19 patients thought to have hypotonic washout by standard diuresis renography, 16 were confirmed as unobstructed by F-15 renography and all were initially treated conservatively, although 1 patient re-presented after 3 years with recurrent loin pain and underwent pyeloplasty without further renographic assessment. However, 2 kidneys thought to have hypotonic washout on standard diuresis renography were judged to have equivocal washout by F-15 renography and underwent pyeloplasty for continuing symptoms. Furthermore, one kidney considered to have hypotonic unobstructed washout by standard diuresis renography was shown to be obstructed on F-15 renography (Fig. 1) and underwent pyeloplasty, at which time prominent aberrant lower pole vessels were demonstrated crossing the pelviureteric junction. Obstructed washout (Type 11) was seen in 4 kidneys on the initial standard diuresis renogram and all of these were confirmed as obstructed by the F- 15renogram. Two of these kidneys underwent pyeloplasty, 1 percutaneous pyelolithotomy and 1 nephrectomy after failed pyeloplasty. Equivocal washout (Type IIIb) was demonstrated in 23 cases using standard diuresis renography. The F-15 renogram clarified washout in 21 of these. Thirteen were shown to be unobstructed by the F-15 renogram (Fig. 2) and were treated conservatively. Eight kidneys were shown to be obstructed by the F-15 renogram; 4 of these underwent pyeloplasty, 2 required nephrectomy, 1 patient passed an obstructing stone, and 1 patient with spina bifida and multiple medical problems was treated conservatively. Only 2 kidneys remained equivocal after F-15 renography and both of these were treated conservatively. Final outcome, including renographic assessment and symptoms A total of 39 cases were considered to be unobstructed on the initial F-15 renogram. All of these
127
were treated conservatively and at final assessment the elimination pattern had changed in only 1 patient; this was due to an undiagnosed asymptomatic stone moving down into the ureter causing obstruction. The remaining 38 cases with an unobstructed F-15 renogram remained unobstructed. There was a significant loss of relative function (>5%) in 4 patients. However, 2 of these had chronic stone disease and 1 had undergone surgery to that kidney, leaving only 1 with an unexplained loss of relative function. The drop in relative function in this case was 7% which, although renographically significant, is unlikely to have any clinical significance. 21 patients who had unobstructed F- 15 renograms were completely symptom-free at follow-up. A further 9 patients had identifiable non-renal disease as the cause of their original symptoms (5 orthopaedic, 2 gynaecological and 2 gastrointestinal). Nine patients had persistent symptoms suggesting a renal origin; in 5 of these the symptoms were due to identifiable renal disease (3 recurrent urinary tract infections, 2 recurrent stone formers), and a further patient, who has already been mentioned, underwent a pyeloplasty but continues to have intermittent loin pain. This leaves 3 patients with persistent unexplained pain of presumed renal origin in whom there has been no change in drainage pattern or deterioration in relative function since initial assessment. All patients with obstructed F-15 renograms at initial assessment who underwent corrective surgery showed an improvement in drainage, with relative function either improved or stable at followup assessment. Furthermore, all of these patients were free of renal pain except for one who was passing “gravel” intermittently in his urine. The 2 stone patients (1 passed his stone spontaneously and the other required percutaneous nephrolithotomy) were symptom-free with improvement in both drainage and function. The spina bifida patient who was unfit for surgery, and was therefore treated conservatively, remains obstructed with loss of renal function in that kidney. The 2 patients with equivocal F-15 renograms who were treated conservatively had stable renal function and stable or improved drainage. One was completely symptom-free whilst the other suffered from recurrent urinary tract infections and abdominal pain thought to be gastrointestinal in origin. The remaining 2 equivocal patients underwent pyeloplasty. One of these had a good result in terms of increased relative function but continued to complain of recurrent renal pain. The drainage pattern of the F-15 renogram remained equivocal
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Fig. 1 (A) Standard diuresis renogram showing hypotonic washout from left kidney. (B) F-15 renogram in same patient showing obstructed left kidney at high urine flow rates.
129
SUSPECTED OBSTRUCTION OF THE UPPER URINARY TRACT
30
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Fig. 2 (A) Standard diuresis renogram showing equivocal washout from left kidney. (B) F-15 renogram in same patient showing unobstructed left kidney.
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BRITISH JOURNAL OF UROLOGY
designed to increase urine flow rates during renography have been described by Sukhai et al. (1986) and English et al. (1987). The rationale behind these modifications is that the diuresis produced by standard diuresis renography may be insufficient to produce washout in grossly dilated systems (Zechman, 1988; Kletter and Nurnberger, 1989) or in kidneys with impaired renal function (O’Reilly, 1986; Hjortso et al., 1988). This may result in an Discussion equivocal or even obstructed curve in the absence The diuresis renogram was introduced into clinical of true obstruction. Furthermore, a false negative practice by O’Reilly in 1978. The purpose of the result may be obtained in cases of intermittent test is to distinguish between the dilated but pelviureteric obstruction that obstruct only at high unobstructed upper urinary tract and the truly urine flow rates (O’Reilly, 1989). We have demonobstructed kidney. In the majority of cases the strated in other studies that diuretic-induced uristandard diuresis renogram will do just that. nary flow rates reach a maximum 16 to 18 min after However, in up to 17% of cases the results of an intravenous injection of frusemide and that even diuresis renography will be equivocal (O’Reilly, at creatinine clearances as low as 40 ml/min the 1987; Upsdell er al., 1990) and the question “is the urine flow rates 15 min after frusemide are sufficient kidney significantly obstructed?” will not be an- to produce unequivocal washout curves (Upsdell et swered. In an attempt to improve the accuracy of al., 1988; Brown et al., 1992). The timing of the diuresis renogram in the diagnosis of obstructive frusemide in F-15 renography, 15 min before the uropathy various modifications of technique or injection of radiopharmaceutical, therefore results analysis have been introduced. Deconvolution in maximal urinary flow rates occurring at the start analysis of the renogram with calculation of of the renogram. This should ensure that the parenchymal transit time (PTT) is said to be a more incidence of false positive results is minimised in sensitive indicator of obstruction than standard grossly dilated or poorly functioning systems. In diuresis renography (Cosgriff and Berry, 1982; addition, the increase in urine flow rates may be Britton et al., 1987). However, other authors have sufficient to cause obstruction in those systems that demonstrated little advantage over standard di- obstruct only at high urine flow rates. uresis renography (Lupton et al., 1984) and the The results of the present study have shown that complexity of deconvolution analysis, the difficul- there was generally good agreement between standties in analysing the renogram, particularly in ard renography and F-15 renography when the children (Vivian et al., 1985), and the availability results of the standard renogram were unequivocal. of the simpler diuresis renogram have restricted the However, it is of interest that 1 patient who use of PTT in the investigation of dilated upper demonstrated an unobstructed hypotonic pattern tracts. on standard diuresis renography was shown to be Attempts to improve the diagnostic accuracy of obstructed at high flow rate using modified renogthe diuresis renogram by quantifying the response raphy, and subsequently required surgery. This of the renogram curve have been made using a patient presented with typical symptoms of internumber of methods. The diuresis excretion index mittent pelviureteric obstruction with loin pain (DEI) was introduced by O’Reilly in 1978 for use after alcohol consumption and represents one of with probe renograms and was later adapted to the the group of patients who obstruct only at high gamma camera renogram (English et al., 1987). urine flow rate and who may not be identified by Radionuclide clearance half times, which measure conventional radiographic or renographic investithe time taken to clear half of the activity present gations. In the vast majority of cases a nonin the kidneys after the injection of frusemide, have obstructed result on standard diuresis renography been calculated for obstructed and unobstructed will be a reliable assessment of upper tract drainage kidneys (Maizels et al., 1986). Unfortunately, both and management decisions can be taken without the DEI and clearance half times suffer from the need for modified renography. However, in problems in defining the normal and obstructed those patients whose clinical presentation is ranges and both indices have a considerable range strongly suggestive of upper tract obstruction, an F-15 renogram should be performed even in the of equivocal results. Modfications of the diuresis renogram which are presence of an unobstructed standard diuresis
and she therefore underwent further renal exploration at which no significant renal cause for her pain could be identified. The second patient who underwent pyeloplasty was more successful and showed symptomatic as well as renographic improvement following surgery.
SUSPECTED OBSTRUCTION OF THE UPPER URINARY TRACT
renogram, to exclude high flow, intermittent, pelviureteric junction obstruction. An obstructed F-15 renogram appears to be an indication for surgery, and all of the patients in this study who underwent reconstructive surgery on this basis showed both symptomatic and renographic improvement at follow-up. All but 2 of the 39 patients with unobstructed F15 renograms remained unobstructed on conservative management. One obstructed with an undiagnosed asymptomatic ureteric stone and the other underwent pyeloplasty 3 years after an unobstructed F-15 renogram without further renographic assessment; it is therefore difficult to comment on the significance of this case. There was no significant unexplained loss of relative function in this unobstructed group, and only 3 patients with persistent unexplained symptoms likely to be of renal origin. It would therefore appear safe to recommend conservative management in this group with unobstructed F-15 renograms. Equivocal washout occurred in 23 of 55 cases using standard diuresis renography in this highly selective group with suspected obstruction of the upper urinary tract. F-15 renography clarified washout in 21 cases. An additional 2 cases of equivocal washout were revealed by F-15 renography, making a total of only 4 cases (7%) using this technique. It was concluded that the F-15 renogram, in which frusemide is given 15 min before the test, appears to provide an accurate assessment of the drainage of the upper urinary tract. The incidence of equivocal results in the renographic assessment of suspected upper tract obstruction is significantly reduced by F-15 renography and this technique is recommended in either renographically or clinically equivocal cases.
Acknowledgements This study was supported in part by the North West Kidney Research Association. We are indebted to Messrs E. Charlton Edwards, R. N . P. Carroll and S. R. Payne for permission to study their patients.
References Britton, K. E., Nawaz, M. K., Whitfield, H. N. et d. (1987). Obstructive nephropathy ; comparison between parenchymal transit time index and frusemide diuresis. Br. J. Urol., 59, 127-132. Brown, S. C. W., Upsdell, S, M. and O’Reilly, P. H. (1992). The importance of renal function in the interpretation of diuresis renography. Br. J. Uro1.,69, 121-125.
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Cosgriff, P. S. and Berry, J. M. (1982).A comparative assessment of deconvolution and diuresis renography in equivocal upper urinary tract obstruction. Nucl. Med. Commun., 3, 377-384. English, P. J., Testa, H. J., Lawson, R. S. et d. (1987). Modified method of diuresis renography for the assessment of equivocal pelviureteric obstruction. Br. J. Urol.,59, 10-14. Hjortso, E., Fugleberg, S., Nielsen, L. et d. (1988). Diuresis renography in patients with reduced renal function. Dan. Med. Bull., 35,294-295. Kletter, K. and Nurnberger, N. (1989). Diagnostic potential of diuresis renography ; limitation by the severity of hydronephrosis and by impairment of renal function. Nucl. Med. Commun., 10,5141. Lupton, E. W., Lawson, R. S., Shields, R. A. et d. (1984).Diuresis renography and parenchymal transit times in the assessment of renal pelvic dilatation. Nucl. Med. Commun., 5,451459. Maizels, M., Firlit, C. F., Conway, J. J. et (II. (1986). Trouble shooting the diuresis renogram. J. Urol., 28,355-363. O’Reilly, P. H. (1986). Diuresis renography 8 years later; an update. J. Urol., 136,993-999. OReilly, P. H. (1987). Current status of diuretic renography. In Nuclear Medicine Annual, ed. Freeman, L. H. and Weissman, H. S. Pp. 173-192. New York: Raven Press. O’Reilly, P. H. (1989). Relationship between intermittent hydronephrosis and megacalicosis. Br. J. Urol., 64, 125-129. O’Reilly, P. H., Testa, H. J., Lawson, R. S. etd. (1978). Diuresis renography in equivocal urinary tract obstruction. Br. J. Urol., 50,76-80. Sukhai, R. N., Kooy, P. P. M., Wolff, E. D. et d. (1986). Predictive value of 99m Tc-DTPA renography studies under conditions of maximal diuresis for the functional outcome of reconstructive surgery in children with obstructive uropathy. Br. J. Urol., 58,596-600. Upsdell, S. M., Leeson, S. M., Brooman, P. J. C. et d. (1988). Diuretic-induced urinary flow rates at varying clearances and their relevance to the performance and interpretation of diuresis renography. Br. J. Urol., 61, 14-18. Upsdell, S. M., Testa, H. J., Lawson, R. S. et al. (1990). The uses and interpretation of modified diuresis renography. In Radionuclides in Nephro-urology, ed. Blaufox, M. D., Hollenberg, N. K. and Raynaud, C. Volume 79, pp. 103-107. Basel: Karger. Vivian, G., Barratt, T. M., Todd-Pokropek, A. et d. (1985). Physiological variations of normal transit time in children. Eur. J. Nucl. Med., 11, 179-181. Zechmann, w . (1988). An experimental approach to explain some misinterpretations of diuresis renography. Nucl. Med. Commun., 9,283-294.
The Authors S. M. Upsdell, MD, FRCS, formerly Research Fellow in Urology, Manchester Royal Infirmary. Now Senior Registrar in Urology, University Hospital of South Manchester. H. J. Testa, MD, PhD, FRCP, FRCR, Consultant and Head of Department of Nuclear Medicine, Manchester Royal Infirmary. R. S. Lawson, BSc, PhD, Principal Physicist, Department of Nuclear Medicine, Manchester Royal Infirmary Requests for reprints to: S. M. Upsdell, Department of Urology, University Hospital of South Manchester, Nell Lane, West Didsbury, Manchester M20 8LR.
01992 British Journalof Urology
The F- 15 Diuresis Renogram in Suspected Obstruction of the Upper Urinary Tract S . M. UPSDELL, H. J. TESTA and R. S. LAWSON Departments of Nuclear Medicine and Urology, Manchester Royal Infirmary, Manchester
Summary-The results are presented of the first long-term follow-up study of patients with suspected obstruction of the upper urinary tract investigated by a modified form of diuresis renography (F- 15 renography). The incidence of equivocal results from diuresis renography is significantly reduced by the use of the F- 15 renogram. F- 15 renography provides a reliable assessment of the upper urinary tract in patients with suspected obstruction and is recommended in the investigation of equivocal upper urinary tract dilatation.
Diuresis renography is widely accepted in clinical practice for the investigation of dilated upper urinary tracts. Despite over 12 years’ experience with this technique, however, equivocal results are still obtained in up to 17% of cases (Upsdell et af., 1990). For several years we have been investigating a modified method of diuresis renography in which frusemide is given intravenously 15 min before the radiopharmaceutical (English et af., 1987), a technique which we refer to as F-15 renography. This timing of frusemide has been shown to maximise urinary flow rates (Upsdell et al., 1988; Brown et af., 1992). We report the results of the first longterm follow-up study of 50 patients investigated by this technique and discuss the clinical indications for F-15 diuresis renography. Patients and Methods All patients under the care of a single Department of Urology who were initially investigated for suspected obstruction of the upper urinary tract by both standard and F-15 diuresis renography were entered into the study. Between 1982 and 1987 70 such patients were seen in this department. On follow-up, 2 had died of non-renal causes, 1 was pregnant, 1 declined further follow-up owing to severe arthritis and reduced mobility and 16 had Accepted for publication 3 September 1991
either moved out of the area or defaulted. This left 50 patients, 13 male and 37 female, with 55 symptomatic kidneys available for review. Their ages ranged from 22 to 69 years (mean 40). All patients had suspected obstruction of the upper urinary tract on clinical and/or radiological grounds. All underwent initial assessment by standard gamma camera renography (O’Reilly et al., 1978), followed by F-15 renography in which frusemide is given intravenously in a dose of 0.5 mg/kg bodyweight 15 min beforethe radiopharmaceutical (English et af., 1987). All scans were performed using 231-Hippuran (0.2 MBq/kg body weight) with the patient sitting in front of a gamma camera. The acquired data were analysed using an MDS computer. Four patterns of elimination were identified during the standard diuresis renograms asdescribed by O’Reilly et af. (1978), i.e. unobstructed (type I), obstructed (Type 11), hypotonic (Type IIIa) and equivocal (Type IIIb). In F-15 renography only 3 types of washout curve are identified, namely unobstructed, obstructed and equivocal. The subsequent management of all patients was based on clinical signs and symptoms and the results of the initial F-15 renogram. At the conclusion of the study all patients underwent further clinical, biochemical and renographic assessment. The time between the initial F-15 renogram and the final renographic assessment ranged from 1 to 7 years,
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with a mean follow-up of just over 4 years (50 months). Only 4 patients had a follow-up period of less than 24 months. Results Initial renographic assessment and management There were 32 cases of unequivocal washout on standard diuresis renography (9 unobstructed, 19 hypotonic and 4 obstructed). The results of the F15 renogram agreed with the standard diuresis renogram in all 9 unobstructed cases and these patients were all treated conservatively. Of the 19 patients thought to have hypotonic washout by standard diuresis renography, 16 were confirmed as unobstructed by F-15 renography and all were initially treated conservatively, although 1 patient re-presented after 3 years with recurrent loin pain and underwent pyeloplasty without further renographic assessment. However, 2 kidneys thought to have hypotonic washout on standard diuresis renography were judged to have equivocal washout by F-15 renography and underwent pyeloplasty for continuing symptoms. Furthermore, one kidney considered to have hypotonic unobstructed washout by standard diuresis renography was shown to be obstructed on F-15 renography (Fig. 1) and underwent pyeloplasty, at which time prominent aberrant lower pole vessels were demonstrated crossing the pelviureteric junction. Obstructed washout (Type 11) was seen in 4 kidneys on the initial standard diuresis renogram and all of these were confirmed as obstructed by the F- 15renogram. Two of these kidneys underwent pyeloplasty, 1 percutaneous pyelolithotomy and 1 nephrectomy after failed pyeloplasty. Equivocal washout (Type IIIb) was demonstrated in 23 cases using standard diuresis renography. The F-15 renogram clarified washout in 21 of these. Thirteen were shown to be unobstructed by the F-15 renogram (Fig. 2) and were treated conservatively. Eight kidneys were shown to be obstructed by the F-15 renogram; 4 of these underwent pyeloplasty, 2 required nephrectomy, 1 patient passed an obstructing stone, and 1 patient with spina bifida and multiple medical problems was treated conservatively. Only 2 kidneys remained equivocal after F-15 renography and both of these were treated conservatively. Final outcome, including renographic assessment and symptoms A total of 39 cases were considered to be unobstructed on the initial F-15 renogram. All of these
127
were treated conservatively and at final assessment the elimination pattern had changed in only 1 patient; this was due to an undiagnosed asymptomatic stone moving down into the ureter causing obstruction. The remaining 38 cases with an unobstructed F-15 renogram remained unobstructed. There was a significant loss of relative function (>5%) in 4 patients. However, 2 of these had chronic stone disease and 1 had undergone surgery to that kidney, leaving only 1 with an unexplained loss of relative function. The drop in relative function in this case was 7% which, although renographically significant, is unlikely to have any clinical significance. 21 patients who had unobstructed F- 15 renograms were completely symptom-free at follow-up. A further 9 patients had identifiable non-renal disease as the cause of their original symptoms (5 orthopaedic, 2 gynaecological and 2 gastrointestinal). Nine patients had persistent symptoms suggesting a renal origin; in 5 of these the symptoms were due to identifiable renal disease (3 recurrent urinary tract infections, 2 recurrent stone formers), and a further patient, who has already been mentioned, underwent a pyeloplasty but continues to have intermittent loin pain. This leaves 3 patients with persistent unexplained pain of presumed renal origin in whom there has been no change in drainage pattern or deterioration in relative function since initial assessment. All patients with obstructed F-15 renograms at initial assessment who underwent corrective surgery showed an improvement in drainage, with relative function either improved or stable at followup assessment. Furthermore, all of these patients were free of renal pain except for one who was passing “gravel” intermittently in his urine. The 2 stone patients (1 passed his stone spontaneously and the other required percutaneous nephrolithotomy) were symptom-free with improvement in both drainage and function. The spina bifida patient who was unfit for surgery, and was therefore treated conservatively, remains obstructed with loss of renal function in that kidney. The 2 patients with equivocal F-15 renograms who were treated conservatively had stable renal function and stable or improved drainage. One was completely symptom-free whilst the other suffered from recurrent urinary tract infections and abdominal pain thought to be gastrointestinal in origin. The remaining 2 equivocal patients underwent pyeloplasty. One of these had a good result in terms of increased relative function but continued to complain of recurrent renal pain. The drainage pattern of the F-15 renogram remained equivocal
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Fig. 1 (A) Standard diuresis renogram showing hypotonic washout from left kidney. (B) F-15 renogram in same patient showing obstructed left kidney at high urine flow rates.
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30
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Fig. 2 (A) Standard diuresis renogram showing equivocal washout from left kidney. (B) F-15 renogram in same patient showing unobstructed left kidney.
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designed to increase urine flow rates during renography have been described by Sukhai et al. (1986) and English et al. (1987). The rationale behind these modifications is that the diuresis produced by standard diuresis renography may be insufficient to produce washout in grossly dilated systems (Zechman, 1988; Kletter and Nurnberger, 1989) or in kidneys with impaired renal function (O’Reilly, 1986; Hjortso et al., 1988). This may result in an Discussion equivocal or even obstructed curve in the absence The diuresis renogram was introduced into clinical of true obstruction. Furthermore, a false negative practice by O’Reilly in 1978. The purpose of the result may be obtained in cases of intermittent test is to distinguish between the dilated but pelviureteric obstruction that obstruct only at high unobstructed upper urinary tract and the truly urine flow rates (O’Reilly, 1989). We have demonobstructed kidney. In the majority of cases the strated in other studies that diuretic-induced uristandard diuresis renogram will do just that. nary flow rates reach a maximum 16 to 18 min after However, in up to 17% of cases the results of an intravenous injection of frusemide and that even diuresis renography will be equivocal (O’Reilly, at creatinine clearances as low as 40 ml/min the 1987; Upsdell er al., 1990) and the question “is the urine flow rates 15 min after frusemide are sufficient kidney significantly obstructed?” will not be an- to produce unequivocal washout curves (Upsdell et swered. In an attempt to improve the accuracy of al., 1988; Brown et al., 1992). The timing of the diuresis renogram in the diagnosis of obstructive frusemide in F-15 renography, 15 min before the uropathy various modifications of technique or injection of radiopharmaceutical, therefore results analysis have been introduced. Deconvolution in maximal urinary flow rates occurring at the start analysis of the renogram with calculation of of the renogram. This should ensure that the parenchymal transit time (PTT) is said to be a more incidence of false positive results is minimised in sensitive indicator of obstruction than standard grossly dilated or poorly functioning systems. In diuresis renography (Cosgriff and Berry, 1982; addition, the increase in urine flow rates may be Britton et al., 1987). However, other authors have sufficient to cause obstruction in those systems that demonstrated little advantage over standard di- obstruct only at high urine flow rates. uresis renography (Lupton et al., 1984) and the The results of the present study have shown that complexity of deconvolution analysis, the difficul- there was generally good agreement between standties in analysing the renogram, particularly in ard renography and F-15 renography when the children (Vivian et al., 1985), and the availability results of the standard renogram were unequivocal. of the simpler diuresis renogram have restricted the However, it is of interest that 1 patient who use of PTT in the investigation of dilated upper demonstrated an unobstructed hypotonic pattern tracts. on standard diuresis renography was shown to be Attempts to improve the diagnostic accuracy of obstructed at high flow rate using modified renogthe diuresis renogram by quantifying the response raphy, and subsequently required surgery. This of the renogram curve have been made using a patient presented with typical symptoms of internumber of methods. The diuresis excretion index mittent pelviureteric obstruction with loin pain (DEI) was introduced by O’Reilly in 1978 for use after alcohol consumption and represents one of with probe renograms and was later adapted to the the group of patients who obstruct only at high gamma camera renogram (English et al., 1987). urine flow rate and who may not be identified by Radionuclide clearance half times, which measure conventional radiographic or renographic investithe time taken to clear half of the activity present gations. In the vast majority of cases a nonin the kidneys after the injection of frusemide, have obstructed result on standard diuresis renography been calculated for obstructed and unobstructed will be a reliable assessment of upper tract drainage kidneys (Maizels et al., 1986). Unfortunately, both and management decisions can be taken without the DEI and clearance half times suffer from the need for modified renography. However, in problems in defining the normal and obstructed those patients whose clinical presentation is ranges and both indices have a considerable range strongly suggestive of upper tract obstruction, an F-15 renogram should be performed even in the of equivocal results. Modfications of the diuresis renogram which are presence of an unobstructed standard diuresis
and she therefore underwent further renal exploration at which no significant renal cause for her pain could be identified. The second patient who underwent pyeloplasty was more successful and showed symptomatic as well as renographic improvement following surgery.
SUSPECTED OBSTRUCTION OF THE UPPER URINARY TRACT
renogram, to exclude high flow, intermittent, pelviureteric junction obstruction. An obstructed F-15 renogram appears to be an indication for surgery, and all of the patients in this study who underwent reconstructive surgery on this basis showed both symptomatic and renographic improvement at follow-up. All but 2 of the 39 patients with unobstructed F15 renograms remained unobstructed on conservative management. One obstructed with an undiagnosed asymptomatic ureteric stone and the other underwent pyeloplasty 3 years after an unobstructed F-15 renogram without further renographic assessment; it is therefore difficult to comment on the significance of this case. There was no significant unexplained loss of relative function in this unobstructed group, and only 3 patients with persistent unexplained symptoms likely to be of renal origin. It would therefore appear safe to recommend conservative management in this group with unobstructed F-15 renograms. Equivocal washout occurred in 23 of 55 cases using standard diuresis renography in this highly selective group with suspected obstruction of the upper urinary tract. F-15 renography clarified washout in 21 cases. An additional 2 cases of equivocal washout were revealed by F-15 renography, making a total of only 4 cases (7%) using this technique. It was concluded that the F-15 renogram, in which frusemide is given 15 min before the test, appears to provide an accurate assessment of the drainage of the upper urinary tract. The incidence of equivocal results in the renographic assessment of suspected upper tract obstruction is significantly reduced by F-15 renography and this technique is recommended in either renographically or clinically equivocal cases.
Acknowledgements This study was supported in part by the North West Kidney Research Association. We are indebted to Messrs E. Charlton Edwards, R. N . P. Carroll and S. R. Payne for permission to study their patients.
References Britton, K. E., Nawaz, M. K., Whitfield, H. N. et d. (1987). Obstructive nephropathy ; comparison between parenchymal transit time index and frusemide diuresis. Br. J. Urol., 59, 127-132. Brown, S. C. W., Upsdell, S, M. and O’Reilly, P. H. (1992). The importance of renal function in the interpretation of diuresis renography. Br. J. Uro1.,69, 121-125.
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Cosgriff, P. S. and Berry, J. M. (1982).A comparative assessment of deconvolution and diuresis renography in equivocal upper urinary tract obstruction. Nucl. Med. Commun., 3, 377-384. English, P. J., Testa, H. J., Lawson, R. S. et d. (1987). Modified method of diuresis renography for the assessment of equivocal pelviureteric obstruction. Br. J. Urol.,59, 10-14. Hjortso, E., Fugleberg, S., Nielsen, L. et d. (1988). Diuresis renography in patients with reduced renal function. Dan. Med. Bull., 35,294-295. Kletter, K. and Nurnberger, N. (1989). Diagnostic potential of diuresis renography ; limitation by the severity of hydronephrosis and by impairment of renal function. Nucl. Med. Commun., 10,5141. Lupton, E. W., Lawson, R. S., Shields, R. A. et d. (1984).Diuresis renography and parenchymal transit times in the assessment of renal pelvic dilatation. Nucl. Med. Commun., 5,451459. Maizels, M., Firlit, C. F., Conway, J. J. et (II. (1986). Trouble shooting the diuresis renogram. J. Urol., 28,355-363. O’Reilly, P. H. (1986). Diuresis renography 8 years later; an update. J. Urol., 136,993-999. OReilly, P. H. (1987). Current status of diuretic renography. In Nuclear Medicine Annual, ed. Freeman, L. H. and Weissman, H. S. Pp. 173-192. New York: Raven Press. O’Reilly, P. H. (1989). Relationship between intermittent hydronephrosis and megacalicosis. Br. J. Urol., 64, 125-129. O’Reilly, P. H., Testa, H. J., Lawson, R. S. etd. (1978). Diuresis renography in equivocal urinary tract obstruction. Br. J. Urol., 50,76-80. Sukhai, R. N., Kooy, P. P. M., Wolff, E. D. et d. (1986). Predictive value of 99m Tc-DTPA renography studies under conditions of maximal diuresis for the functional outcome of reconstructive surgery in children with obstructive uropathy. Br. J. Urol., 58,596-600. Upsdell, S. M., Leeson, S. M., Brooman, P. J. C. et d. (1988). Diuretic-induced urinary flow rates at varying clearances and their relevance to the performance and interpretation of diuresis renography. Br. J. Urol., 61, 14-18. Upsdell, S. M., Testa, H. J., Lawson, R. S. et al. (1990). The uses and interpretation of modified diuresis renography. In Radionuclides in Nephro-urology, ed. Blaufox, M. D., Hollenberg, N. K. and Raynaud, C. Volume 79, pp. 103-107. Basel: Karger. Vivian, G., Barratt, T. M., Todd-Pokropek, A. et d. (1985). Physiological variations of normal transit time in children. Eur. J. Nucl. Med., 11, 179-181. Zechmann, w . (1988). An experimental approach to explain some misinterpretations of diuresis renography. Nucl. Med. Commun., 9,283-294.
The Authors S. M. Upsdell, MD, FRCS, formerly Research Fellow in Urology, Manchester Royal Infirmary. Now Senior Registrar in Urology, University Hospital of South Manchester. H. J. Testa, MD, PhD, FRCP, FRCR, Consultant and Head of Department of Nuclear Medicine, Manchester Royal Infirmary. R. S. Lawson, BSc, PhD, Principal Physicist, Department of Nuclear Medicine, Manchester Royal Infirmary Requests for reprints to: S. M. Upsdell, Department of Urology, University Hospital of South Manchester, Nell Lane, West Didsbury, Manchester M20 8LR.
