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Dynamic Renal Scan in the Non-Visualizing Kidney
0022-5347/79/1212-0148$02. 00/0
THE JOURNAL OF UROLOGY Copyright © 1979 by The Williams & Wilkins Co.
Vol. 121, February
Printed in U.S.A.
DYNAMIC RENAL SCAN IN THE NON-VISUALIZING KIDNEY LEON G. LOME, STEVEN PINSKY
AND
LAWRENCE LEVY
From the Divisions of Urology and Nuclear Medicine, Michael Reese Hospital and Medical Center, Chicago, Illinois
ABSTRACT
Thirty-one patients with 35 non-visualizing kidneys on excretory urography were studied with mtechnetium-diethylenetriaminepentaacetic acid scintiscanning. In 11 cases good renal blood flow and concentration were demonstrated on nucleide scanning. All patients had significant parenchyma and recoverable renal function after appropriate surgical management. In 20 cases there was little or no blood flow on the scan. These patients either had a congenitally absent kidney or severely destroyed parenchyma. The 99mtechnetium-diethylenetriaminepentaacetic acid dynamic renal scan is a sensitive method for predicting renal salvageability of a kidney that fails to visualize on excretory urography.
99
The excretory urogram (IVP) serves as the primary investigative tool for the urologist. However, non-visualization of one or both kidneys is encountered often in a number of uropathic conditions. Retrograde pyelography, angiography, venography and sonography have been used to· evaluate further the non-visualizing kidney. More recently, radioisotope renal scintiscanning has been suggested for this purpose. 1 The dynamic renal scan is a series of continuous integrated images detected and recorded on a gamma camera after a bolus injection of the radiopharmaceutical 99mtechnetium-diethylenetriaminepentaacetic acid (99mTc-DTPA). This chelate is not metabolized and is excreted exclusively in the urine by glomerular filtration. 2 The role of 99mTc-DTPA renal scintiscanning in assessing the non-visualizing kidney is evaluated herein.
dynamic renal scan were scrutinized carefully. Two groups were identified. In 1 group of non-visualizing kidneys the dynamic renal scan showed normal or nearly normal renal blood flow and concentration with 99mTc-DTPA. In the second group the dynamic renal scan showed significantly diminished to absent renal blood flow and concentration. There were 11 kidneys in group 1 and 20 kidneys in group 2. CASE REPORTS: GROUP 1 Case 1. L. R., a 74-year-old-white man, had undergone cystectomy and ileal conquit diversion for carcinosarcoma of the prostate. Early post-diversion IVPs were normal. An IVP 8 months later showed non-visualization on the left side. The loopogram showed no reflux on the left side (fig. 2, A). The dynamic renal scan showed good blood flow and concentration to the left kidney (fig. 2, B). After a left ureteroileal anastomotic revision the IVP showed return of function in a slightly smaller kidney (fig. 2, C). Case 2. W. S., a 63-year-old black man, had locally exten-
MATERIALS AND METHODS
From 1974 through the present 244 99mTc-DTPA dynamic renal scans have been performed for a variety of nephrological and urological conditions. In 31 cases such nucleide scanning had been done because one or both kidneys had failed to visualize on a routine IVP. These patients are the substance of this report. Patients with chronic renal failure are excluded from this review. Non-visualizing kidneys also were evaluated by means of cystoscopy, retrograde pyelography, angiography and venography. When indicated surgical exploration was undertaken. The findings of these investigations are correlated with the 99mTc-DTPA dynamic renal scan. A bolus of 20 me. 99mTc-DTPA is injected intravenously. Images within the first seconds after injection represent the vascular stage of distribution of radioactivity. The aorta and renal arteries are identified readily (phase 1). Relative blood flow to each kidney also may be identified. Subsequently, the concentration and the distribution of the chelate depend on the functional status of each kidney. Images up to 2 minutes best evaluate regional distribution of functioning renal parenchyma (phase 2). Five-minute views show systematic clearing of radioactivity from the kidney and demonstrate excretory pathways (phase 3). 2 Thus, 3 components of renal physiology are depicted: 1) renal blood flow, 2) distribution of functioning renal mass and 3) renal excretion (fig. 1).
POSTERIOR
3 SEC.
5 SEC.
10 SEC.
10 MIN.
RESULTS
In 31 patients with 35 non-visualizing kidneys on a routine IVP phases 1 and 2 (renal blood flow and concentration) of the Accepted for publication April 14, 1978. Read at annual meeting of North Central Section, American Urological Association, San Diego, California, November 6-12, 1977.
Fm. 1. Normal ••mTc-DTPA dynamic renal scans. Posterior views (patient's left is on reader's left). 148
DYNAMIC RENAL SCAN IN NON-VISUALIZING KIDNEY
149
r I I
Fm. 2. Case 1. A, loopogram shows no reflux into left ureter. B, dynamic renal scan shows good blood flow and concentration to left kidney. C, IVP after left anastomotic revision shows recovery of function.
A
Fm. 3. Case 2. A, dynamic renal scan shows good blood flow and concentration to left kidney. B, IVP shows recovery of function after cutaneous ureterostomy.
sive prostatic carcinoma. He presented with a 24-hour history of oliguria. Catheterization produced 20 cc urine. An IVP showed bilateral non-visualization. A dynamic renal scan showed good blood flow and concentration on the left side (fig. 3, A). Left cutaneous ureterostomy resulted in prompt recovery ofrenal function (fig. 3, B).
Comment. All patients with non-visualizing kidneys on IVP in whom the dynamic renal scan showed normal or nearly normal renal blood flow and concentration underwent definitive surgical procedures in an attempt to salvage the nonfunctioning kidney (table 1). In 3 patients calculi were removed with subsequent recovery of renal function. In 3 pa-
150
LOME, PINSKY AND LEVY
tion on the right side (fig. 4, A). A retrograde pyelogram showed ureteropelvie junction obstruction. Right nephrectomy was performed. Pathology revealed a hydronephrotic shell of kidney (fig. 4, B) with hyalinization of virtually all glomeruli. Case 4. R. A., a 34-year-old black man, had sustained a gunshot wound to the abdomen 3 months earlier. The patient presented with a mass in the left flank and abdomen. An IVP showed non-visualization of the left kidney. The dynamic renal scan showed virtually no renal blood flow or concentration to the left kidney (fig. 5). A urinoma was drained and left nephrectomy was performed. Pathology showed hydronephrosis with severe acute and chronic pyelonephritis. Case 5. J. P., a 62-year-old black man, presented with urinary frequency. An IVP showed left hydroureteronephrosis in a horseshoe kidney with non-visualization of the right segment (fig. 6, A). The dynamic renal scan showed no blood
tients reconstructive procedures (pyeloplasty, ureteroileal anastomotic revision and cutaneous ureterostomy) were done to correct obstructive uropathy and renal function returned in all. In 4 patients nephrostomy drainage was used to bypass the obstruction and renal function returned in all. In 1 patient renal function returned after resection of a bladder tumor from the trigone. CASE REPORTS: GROUP 2 Case 3. R. M., a 14-year-old black boy, presented with a 6month history of recurring right flank pain. An IVP showed a normal left kidney and non-visualization on the right side. A dynamic renal scan showed no renal blood flow or concentraTABLE
1. Non-visualizing kidneys. Group 1. Normal renal blood
flow and perfusion Pt.
Non-Vis.
CA CA PC BE
Rt. Rt. Lt. Lt.
LR
Lt.
ws
Bilat.
JB
Lt.
TM
Bilat. Bilat. Bilat. Rt.
BJ JS JE
Pathology Ureteral calculus Ureteral calculus Staghorn calculus U reteropelvie junction obstruction Ureteroileal anastomosis obstruction Infiltrative prostatic Ca Papillary necrosis, obstruction Infiltrative bladder Ca Infiltrative bladder Ca Infiltrative rectal Ca Bladder Ca rt. hemitrigone
* All kidneys regained function postoperatively.
Operation*
POST
POST
8-10 SEC.
15 min.
Ureterolithotomy Ureterolithotomy Anatropic nephrotomy Pyeloplasty Anastomotic revision Lt. cutaneous ureterostomy Lt. nephrostomy Lt. nephrostomy Rt. nephrostomy Rt. nephrostomy Transurethral resection of bladder tumor
Fm. 5. Case 4. Dynamic renal scan shows no renal blood flow on left side at 8 to 10 seconds.
A
.
.
F,. : • ·...
..
.'-!·;·'.~-·--
Fm. 4. Case 3. A, dynamic renal scan shows no renal blood flow to right kidney. B, hydronephrotic shell secondary to ureteropelvic junction obstruction.
151
DYNAMIC RENAL SCAN IN NON-VISUALIZING KIDNEY
B POSTERIOR
LT.
I
I
I
LIVER
!!
20 MIN.
Fm. 6. Case 5. A, IVP shows left hydronephrosis and non-visualization of right segment of horseshoe kidney. B, dynamic ~,nal scan shows no blood flow on right side at 5 and 17 seconds. Delayed excretion is seen on left side at 20 minutes. · ,
flow or perfusion on the right side and diminished flow and excretion on the left side (fig. 6, B). Renal angiography showed a dysplastic, multicystic right renal segment (fig. 7). Comment. Eleven patients with non-visualizing kidneys on IVP, in whom the dynamic renal scan showed severely diminished or absent renal blood flow and perfusion, underwent surgical exploration and/or nephrectomy (table 2). In 2 cases the kidneys were congenitally dysplastic. In 3 they were hydronephrotic shells of destroyed renal parenchyma behind congenital ureteropelvic junction obstruction. In 3 cases the kidneys had undergone prolonged obstruction, resulting in end stage hydronephrosis and severe pyelonephritis. In 3 patients the renal parenchyma was totally replaced: 1 by infiltrating squamous cell carcinoma of the renal pelvis, 1 by metastatic prostatic carcinoma and 1 by xanthogranulomatous pyelonephritis. In none of the 11 surgical specimens was it believed that there was any potentially salvageable renal parenchyma. Six non-visualizing kidneys with absent renal blood flow and perfusion on 99 mTc-DTPA scanning were found to be congenitally absent (table 2). This finding was confirmed by the absence of the respective ureteral orifice and hemitrigone on cystoscopy and by aortography or venacavography. Three additional kidneys were demonstrated on aortography to be multicystic or dysplastic. DISCUSSION
Radioisotope renal scintiscanning has been suggested as a method to assess the potential reversibility in functional impairment of renal tissue damaged by obstructive disease. However, question has been raised regarding the reliability of these techniques. Kiviat and Griep reported a case in which a 197 Hg chlormerodrin scan showed minimal activity in a nonvisualizing kidney obstructed by a ureteral calculus. 3 On this basis nephrectomy was anticipated. At exploration a healthy appearing kidney was found and ureterolithotomy yielded a normal functioning kidney. These authors caution that scintiscanning in obstruction will give a deceivingly poor impression of renal salvageability but this is in sharp contrast to our
Fm. 7. Case 5. Renal angiogram shows multicystic segment on right side.
experience using 99 mTc-:bTPA scintiscanning. Devenny and associates observed that in early obstruction renal tubular function is altered minimally and tubular agents, such as orthoidiohippurate and chlormerodrin, may be useful in docu-
152
LOME, PINSKY AND LEVY TABLE
Pt.
Non-Vis.
KL BM RM SA NH AI
Rt. Lt. upper pole Rt. Rt. Rt. Rt.
RA
Lt.
JG LP NM
Lt. Rt. Lt. Rt. Rt. Rt. Lt. Rt. Lt. Lt. Rt. Rt. Lt.
cs
EB KO AT CA JE NG JP
cc
BA
2. Non-visualizing kidneys. Group 2. Diminished to absent renal blood fiow and perfusion Pathology
Renal dysplasia, urethral valves Dysplastic segment, ureterocele Ureteropelvic junction obstruction Ureteropelvic junction obstruction Ureteropelvic junction obstruction Hydronephrosis, pyelonephritis, ureteral strict.ure Hydronephrosis, pyelonephritis, ureteral stricture Hydronephrosis, pyelonephritis, bladder Ca Squamous Ca, infiltrating kidney Metastatic prostatic Ca, infiltrating kidney Xanthogranulomatous pyelonephritis Congenitally absent Congenitally absent Congenitally absent Congenitally absent Congenitally absent Congenitally absent Multicystic segment, horseshoe kidney Hypoplastic, dysplastic kidney Hypoplastic, dysplastic kidney
menting decreasing renal function. 4 However, in advanced stages of obstruction in which tubular function is altered maximally a glomerular agent, such as 99mTc-DTPA, is the choice for evaluation of recoverable renal function. These investigators showed that 99mTc-DTPA scintiscan images demonstrated residual function in advanced chronically obstructed kidneys in which 175Hg-chlormerodrin, 1311-hippuran and IVP all had been negative. We have used 99 mTc-DTPA renal scintiscanning to evaluate the non-visualizing kidney on an IVP. In 11 patients good renal blood flow and concentration were demonstrated in the non-visualizing kidney on the scintiscan. Restoration of renal function was observed in each instance after appropriate surgical correction of the obstruction. The dynamic renal scan was of particular value in azotemic patients with bilateral ureteral obstruction. The kidney demonstrating the best renal blood flow and concentration was selected for nephrostomy drainage. In each instance renal function was restored. There appears to be a significant correlation between residual and/ or recoverable renal function in the non-visualizing kidney, and normal or nearly normal renal blood flow and concentration as detected by phases 1 and 2 of the dynamic renal scan. In 20 patients severely diminished to absent renal blood flow and perfusion were demonstrated in the non-visualizing kidney. In 11 of these patients the decision was made to perform a nephrectomy, in preference to a more conservative operation, on the basis of severely impaired renal blood flow and perfusion. In each case the renal parenchyma was found to be hopelessly destroyed or replaced by infiltrative disease. A similar pattern of absent renal blood flow and perfusion was observed when the non-visualizing kidney was congenitally absent. The dynamic renal scan coupled with cystoscopy and retrograde pyelography was a reliable non-invasive method, documenting that a non-visualizing kidney was in fact congenitally absent. Diminished to absent blood flow and perfusion also were observed in these congenitally hypoplastic and dysplastic kidneys. Thus, it appears that the 99mTc-DTPA dynamic renal scan may be a sensitive method for identifying
Operation Rt. Lt. Rt. Rt. Rt. Rt.
Other
nephrect.omy upper pole nephrect.omy nephrectomy nephrectomy nephrectomy nephrectomy
Rt. nephrectomy, drainage urinoma Lt. nephrectomy Rt. radical nephrectomy Exploration, inoperable Rt. nephrectomy No rt. hemitrigone No rt. hemitrigone No It. hemitrigone No rt. hemitrigone, arteriogram No It. hemitrigone, arteriogram No It. hemitrigone, venogram Arteriogram Ureteral atresia, arteriogram Ureteral aplasia, venogram
irretrievable renal destruction or functional impairment in a kidney that fails to visualize on an IVP. REFERENCES 1. Raynaud, C., Koutoulidis, C., Cendron, J. and Freeman, L. M.:
Preoperative identification of a hydronephrotic sac with sequential 99mTc DTPA imaging: case report. J. Urol., 109: 1033, 1973. 2. Reba, R. C., Poulose K. P. and Kirchna, P. T.: Radiolabeled chelates for visualization of kidney function and structure with emphasis on their use in renal insufficiency. Semin. Nucl. Med., 4: 151, 1974. 3. Kiviat, M. D. and Griep, R. J.: Pyonephrosis complicating ureteral obstruction: a limitation of renal scintiscanning in predicting reversibility of renal damage. J. Urol., 109: 339, 1973. 4. Devenny, J., Morales, J. 0. and Kuhl, D. E.: Early sequential and delayed images of technetium-99mSnDTPA in chronic obstructive renal disease. J. Nucl. Med., 16: 525, 1975. EDITORIAL COMMENT Dynamic renal scanning with an agent excreted exclusively by glomerular filtration is a useful new tool for the clinical urologist. The material presented is most convincing for kidneys with total failure to concentrate 99mTc-DTPA (the absent or non-salvageable kidney) and for kidneys with excellent concentration of 99mTc-DTPA (the potentially salvageable kidney). Rather than such a sharp dichotomy, however, a group of patients with non-visualization of the kidneys during IVP is apt to comprise a spectrum with varying degrees of impaired function. One may have difficulty in separating the "nearly normal" from the "significantly decreased". Whenever there is a question of potential renal function additional diagnostic studies, including renal angiography, are indicated. Most modern nuclear medicine facilities use computers to quantify information obtained during examinations. It should be possible to use a computer to analyze the data during dynamic renal scanning and to calculate the relative activity of each kidney. If such a study were combined with serial measurements of radioactivity in the plasma it would be possible to calculate the actual glomerular infiltration rate of each kidney. Such investigations of quantitative analysis of renal function using 99mTc-DTPA are actually in progress at several institutions. S.S.S.
THE JOURNAL OF UROLOGY Copyright © 1979 by The Williams & Wilkins Co.
Vol. 121, February
Printed in U.S.A.
DYNAMIC RENAL SCAN IN THE NON-VISUALIZING KIDNEY LEON G. LOME, STEVEN PINSKY
AND
LAWRENCE LEVY
From the Divisions of Urology and Nuclear Medicine, Michael Reese Hospital and Medical Center, Chicago, Illinois
ABSTRACT
Thirty-one patients with 35 non-visualizing kidneys on excretory urography were studied with mtechnetium-diethylenetriaminepentaacetic acid scintiscanning. In 11 cases good renal blood flow and concentration were demonstrated on nucleide scanning. All patients had significant parenchyma and recoverable renal function after appropriate surgical management. In 20 cases there was little or no blood flow on the scan. These patients either had a congenitally absent kidney or severely destroyed parenchyma. The 99mtechnetium-diethylenetriaminepentaacetic acid dynamic renal scan is a sensitive method for predicting renal salvageability of a kidney that fails to visualize on excretory urography.
99
The excretory urogram (IVP) serves as the primary investigative tool for the urologist. However, non-visualization of one or both kidneys is encountered often in a number of uropathic conditions. Retrograde pyelography, angiography, venography and sonography have been used to· evaluate further the non-visualizing kidney. More recently, radioisotope renal scintiscanning has been suggested for this purpose. 1 The dynamic renal scan is a series of continuous integrated images detected and recorded on a gamma camera after a bolus injection of the radiopharmaceutical 99mtechnetium-diethylenetriaminepentaacetic acid (99mTc-DTPA). This chelate is not metabolized and is excreted exclusively in the urine by glomerular filtration. 2 The role of 99mTc-DTPA renal scintiscanning in assessing the non-visualizing kidney is evaluated herein.
dynamic renal scan were scrutinized carefully. Two groups were identified. In 1 group of non-visualizing kidneys the dynamic renal scan showed normal or nearly normal renal blood flow and concentration with 99mTc-DTPA. In the second group the dynamic renal scan showed significantly diminished to absent renal blood flow and concentration. There were 11 kidneys in group 1 and 20 kidneys in group 2. CASE REPORTS: GROUP 1 Case 1. L. R., a 74-year-old-white man, had undergone cystectomy and ileal conquit diversion for carcinosarcoma of the prostate. Early post-diversion IVPs were normal. An IVP 8 months later showed non-visualization on the left side. The loopogram showed no reflux on the left side (fig. 2, A). The dynamic renal scan showed good blood flow and concentration to the left kidney (fig. 2, B). After a left ureteroileal anastomotic revision the IVP showed return of function in a slightly smaller kidney (fig. 2, C). Case 2. W. S., a 63-year-old black man, had locally exten-
MATERIALS AND METHODS
From 1974 through the present 244 99mTc-DTPA dynamic renal scans have been performed for a variety of nephrological and urological conditions. In 31 cases such nucleide scanning had been done because one or both kidneys had failed to visualize on a routine IVP. These patients are the substance of this report. Patients with chronic renal failure are excluded from this review. Non-visualizing kidneys also were evaluated by means of cystoscopy, retrograde pyelography, angiography and venography. When indicated surgical exploration was undertaken. The findings of these investigations are correlated with the 99mTc-DTPA dynamic renal scan. A bolus of 20 me. 99mTc-DTPA is injected intravenously. Images within the first seconds after injection represent the vascular stage of distribution of radioactivity. The aorta and renal arteries are identified readily (phase 1). Relative blood flow to each kidney also may be identified. Subsequently, the concentration and the distribution of the chelate depend on the functional status of each kidney. Images up to 2 minutes best evaluate regional distribution of functioning renal parenchyma (phase 2). Five-minute views show systematic clearing of radioactivity from the kidney and demonstrate excretory pathways (phase 3). 2 Thus, 3 components of renal physiology are depicted: 1) renal blood flow, 2) distribution of functioning renal mass and 3) renal excretion (fig. 1).
POSTERIOR
3 SEC.
5 SEC.
10 SEC.
10 MIN.
RESULTS
In 31 patients with 35 non-visualizing kidneys on a routine IVP phases 1 and 2 (renal blood flow and concentration) of the Accepted for publication April 14, 1978. Read at annual meeting of North Central Section, American Urological Association, San Diego, California, November 6-12, 1977.
Fm. 1. Normal ••mTc-DTPA dynamic renal scans. Posterior views (patient's left is on reader's left). 148
DYNAMIC RENAL SCAN IN NON-VISUALIZING KIDNEY
149
r I I
Fm. 2. Case 1. A, loopogram shows no reflux into left ureter. B, dynamic renal scan shows good blood flow and concentration to left kidney. C, IVP after left anastomotic revision shows recovery of function.
A
Fm. 3. Case 2. A, dynamic renal scan shows good blood flow and concentration to left kidney. B, IVP shows recovery of function after cutaneous ureterostomy.
sive prostatic carcinoma. He presented with a 24-hour history of oliguria. Catheterization produced 20 cc urine. An IVP showed bilateral non-visualization. A dynamic renal scan showed good blood flow and concentration on the left side (fig. 3, A). Left cutaneous ureterostomy resulted in prompt recovery ofrenal function (fig. 3, B).
Comment. All patients with non-visualizing kidneys on IVP in whom the dynamic renal scan showed normal or nearly normal renal blood flow and concentration underwent definitive surgical procedures in an attempt to salvage the nonfunctioning kidney (table 1). In 3 patients calculi were removed with subsequent recovery of renal function. In 3 pa-
150
LOME, PINSKY AND LEVY
tion on the right side (fig. 4, A). A retrograde pyelogram showed ureteropelvie junction obstruction. Right nephrectomy was performed. Pathology revealed a hydronephrotic shell of kidney (fig. 4, B) with hyalinization of virtually all glomeruli. Case 4. R. A., a 34-year-old black man, had sustained a gunshot wound to the abdomen 3 months earlier. The patient presented with a mass in the left flank and abdomen. An IVP showed non-visualization of the left kidney. The dynamic renal scan showed virtually no renal blood flow or concentration to the left kidney (fig. 5). A urinoma was drained and left nephrectomy was performed. Pathology showed hydronephrosis with severe acute and chronic pyelonephritis. Case 5. J. P., a 62-year-old black man, presented with urinary frequency. An IVP showed left hydroureteronephrosis in a horseshoe kidney with non-visualization of the right segment (fig. 6, A). The dynamic renal scan showed no blood
tients reconstructive procedures (pyeloplasty, ureteroileal anastomotic revision and cutaneous ureterostomy) were done to correct obstructive uropathy and renal function returned in all. In 4 patients nephrostomy drainage was used to bypass the obstruction and renal function returned in all. In 1 patient renal function returned after resection of a bladder tumor from the trigone. CASE REPORTS: GROUP 2 Case 3. R. M., a 14-year-old black boy, presented with a 6month history of recurring right flank pain. An IVP showed a normal left kidney and non-visualization on the right side. A dynamic renal scan showed no renal blood flow or concentraTABLE
1. Non-visualizing kidneys. Group 1. Normal renal blood
flow and perfusion Pt.
Non-Vis.
CA CA PC BE
Rt. Rt. Lt. Lt.
LR
Lt.
ws
Bilat.
JB
Lt.
TM
Bilat. Bilat. Bilat. Rt.
BJ JS JE
Pathology Ureteral calculus Ureteral calculus Staghorn calculus U reteropelvie junction obstruction Ureteroileal anastomosis obstruction Infiltrative prostatic Ca Papillary necrosis, obstruction Infiltrative bladder Ca Infiltrative bladder Ca Infiltrative rectal Ca Bladder Ca rt. hemitrigone
* All kidneys regained function postoperatively.
Operation*
POST
POST
8-10 SEC.
15 min.
Ureterolithotomy Ureterolithotomy Anatropic nephrotomy Pyeloplasty Anastomotic revision Lt. cutaneous ureterostomy Lt. nephrostomy Lt. nephrostomy Rt. nephrostomy Rt. nephrostomy Transurethral resection of bladder tumor
Fm. 5. Case 4. Dynamic renal scan shows no renal blood flow on left side at 8 to 10 seconds.
A
.
.
F,. : • ·...
..
.'-!·;·'.~-·--
Fm. 4. Case 3. A, dynamic renal scan shows no renal blood flow to right kidney. B, hydronephrotic shell secondary to ureteropelvic junction obstruction.
151
DYNAMIC RENAL SCAN IN NON-VISUALIZING KIDNEY
B POSTERIOR
LT.
I
I
I
LIVER
!!
20 MIN.
Fm. 6. Case 5. A, IVP shows left hydronephrosis and non-visualization of right segment of horseshoe kidney. B, dynamic ~,nal scan shows no blood flow on right side at 5 and 17 seconds. Delayed excretion is seen on left side at 20 minutes. · ,
flow or perfusion on the right side and diminished flow and excretion on the left side (fig. 6, B). Renal angiography showed a dysplastic, multicystic right renal segment (fig. 7). Comment. Eleven patients with non-visualizing kidneys on IVP, in whom the dynamic renal scan showed severely diminished or absent renal blood flow and perfusion, underwent surgical exploration and/or nephrectomy (table 2). In 2 cases the kidneys were congenitally dysplastic. In 3 they were hydronephrotic shells of destroyed renal parenchyma behind congenital ureteropelvic junction obstruction. In 3 cases the kidneys had undergone prolonged obstruction, resulting in end stage hydronephrosis and severe pyelonephritis. In 3 patients the renal parenchyma was totally replaced: 1 by infiltrating squamous cell carcinoma of the renal pelvis, 1 by metastatic prostatic carcinoma and 1 by xanthogranulomatous pyelonephritis. In none of the 11 surgical specimens was it believed that there was any potentially salvageable renal parenchyma. Six non-visualizing kidneys with absent renal blood flow and perfusion on 99 mTc-DTPA scanning were found to be congenitally absent (table 2). This finding was confirmed by the absence of the respective ureteral orifice and hemitrigone on cystoscopy and by aortography or venacavography. Three additional kidneys were demonstrated on aortography to be multicystic or dysplastic. DISCUSSION
Radioisotope renal scintiscanning has been suggested as a method to assess the potential reversibility in functional impairment of renal tissue damaged by obstructive disease. However, question has been raised regarding the reliability of these techniques. Kiviat and Griep reported a case in which a 197 Hg chlormerodrin scan showed minimal activity in a nonvisualizing kidney obstructed by a ureteral calculus. 3 On this basis nephrectomy was anticipated. At exploration a healthy appearing kidney was found and ureterolithotomy yielded a normal functioning kidney. These authors caution that scintiscanning in obstruction will give a deceivingly poor impression of renal salvageability but this is in sharp contrast to our
Fm. 7. Case 5. Renal angiogram shows multicystic segment on right side.
experience using 99 mTc-:bTPA scintiscanning. Devenny and associates observed that in early obstruction renal tubular function is altered minimally and tubular agents, such as orthoidiohippurate and chlormerodrin, may be useful in docu-
152
LOME, PINSKY AND LEVY TABLE
Pt.
Non-Vis.
KL BM RM SA NH AI
Rt. Lt. upper pole Rt. Rt. Rt. Rt.
RA
Lt.
JG LP NM
Lt. Rt. Lt. Rt. Rt. Rt. Lt. Rt. Lt. Lt. Rt. Rt. Lt.
cs
EB KO AT CA JE NG JP
cc
BA
2. Non-visualizing kidneys. Group 2. Diminished to absent renal blood fiow and perfusion Pathology
Renal dysplasia, urethral valves Dysplastic segment, ureterocele Ureteropelvic junction obstruction Ureteropelvic junction obstruction Ureteropelvic junction obstruction Hydronephrosis, pyelonephritis, ureteral strict.ure Hydronephrosis, pyelonephritis, ureteral stricture Hydronephrosis, pyelonephritis, bladder Ca Squamous Ca, infiltrating kidney Metastatic prostatic Ca, infiltrating kidney Xanthogranulomatous pyelonephritis Congenitally absent Congenitally absent Congenitally absent Congenitally absent Congenitally absent Congenitally absent Multicystic segment, horseshoe kidney Hypoplastic, dysplastic kidney Hypoplastic, dysplastic kidney
menting decreasing renal function. 4 However, in advanced stages of obstruction in which tubular function is altered maximally a glomerular agent, such as 99mTc-DTPA, is the choice for evaluation of recoverable renal function. These investigators showed that 99mTc-DTPA scintiscan images demonstrated residual function in advanced chronically obstructed kidneys in which 175Hg-chlormerodrin, 1311-hippuran and IVP all had been negative. We have used 99 mTc-DTPA renal scintiscanning to evaluate the non-visualizing kidney on an IVP. In 11 patients good renal blood flow and concentration were demonstrated in the non-visualizing kidney on the scintiscan. Restoration of renal function was observed in each instance after appropriate surgical correction of the obstruction. The dynamic renal scan was of particular value in azotemic patients with bilateral ureteral obstruction. The kidney demonstrating the best renal blood flow and concentration was selected for nephrostomy drainage. In each instance renal function was restored. There appears to be a significant correlation between residual and/ or recoverable renal function in the non-visualizing kidney, and normal or nearly normal renal blood flow and concentration as detected by phases 1 and 2 of the dynamic renal scan. In 20 patients severely diminished to absent renal blood flow and perfusion were demonstrated in the non-visualizing kidney. In 11 of these patients the decision was made to perform a nephrectomy, in preference to a more conservative operation, on the basis of severely impaired renal blood flow and perfusion. In each case the renal parenchyma was found to be hopelessly destroyed or replaced by infiltrative disease. A similar pattern of absent renal blood flow and perfusion was observed when the non-visualizing kidney was congenitally absent. The dynamic renal scan coupled with cystoscopy and retrograde pyelography was a reliable non-invasive method, documenting that a non-visualizing kidney was in fact congenitally absent. Diminished to absent blood flow and perfusion also were observed in these congenitally hypoplastic and dysplastic kidneys. Thus, it appears that the 99mTc-DTPA dynamic renal scan may be a sensitive method for identifying
Operation Rt. Lt. Rt. Rt. Rt. Rt.
Other
nephrect.omy upper pole nephrect.omy nephrectomy nephrectomy nephrectomy nephrectomy
Rt. nephrectomy, drainage urinoma Lt. nephrectomy Rt. radical nephrectomy Exploration, inoperable Rt. nephrectomy No rt. hemitrigone No rt. hemitrigone No It. hemitrigone No rt. hemitrigone, arteriogram No It. hemitrigone, arteriogram No It. hemitrigone, venogram Arteriogram Ureteral atresia, arteriogram Ureteral aplasia, venogram
irretrievable renal destruction or functional impairment in a kidney that fails to visualize on an IVP. REFERENCES 1. Raynaud, C., Koutoulidis, C., Cendron, J. and Freeman, L. M.:
Preoperative identification of a hydronephrotic sac with sequential 99mTc DTPA imaging: case report. J. Urol., 109: 1033, 1973. 2. Reba, R. C., Poulose K. P. and Kirchna, P. T.: Radiolabeled chelates for visualization of kidney function and structure with emphasis on their use in renal insufficiency. Semin. Nucl. Med., 4: 151, 1974. 3. Kiviat, M. D. and Griep, R. J.: Pyonephrosis complicating ureteral obstruction: a limitation of renal scintiscanning in predicting reversibility of renal damage. J. Urol., 109: 339, 1973. 4. Devenny, J., Morales, J. 0. and Kuhl, D. E.: Early sequential and delayed images of technetium-99mSnDTPA in chronic obstructive renal disease. J. Nucl. Med., 16: 525, 1975. EDITORIAL COMMENT Dynamic renal scanning with an agent excreted exclusively by glomerular filtration is a useful new tool for the clinical urologist. The material presented is most convincing for kidneys with total failure to concentrate 99mTc-DTPA (the absent or non-salvageable kidney) and for kidneys with excellent concentration of 99mTc-DTPA (the potentially salvageable kidney). Rather than such a sharp dichotomy, however, a group of patients with non-visualization of the kidneys during IVP is apt to comprise a spectrum with varying degrees of impaired function. One may have difficulty in separating the "nearly normal" from the "significantly decreased". Whenever there is a question of potential renal function additional diagnostic studies, including renal angiography, are indicated. Most modern nuclear medicine facilities use computers to quantify information obtained during examinations. It should be possible to use a computer to analyze the data during dynamic renal scanning and to calculate the relative activity of each kidney. If such a study were combined with serial measurements of radioactivity in the plasma it would be possible to calculate the actual glomerular infiltration rate of each kidney. Such investigations of quantitative analysis of renal function using 99mTc-DTPA are actually in progress at several institutions. S.S.S.