Renogram Research Articles

Comparison of Camera-Based 99mTc-MAG3 and 24-Hour Creatinine Clearances for Evaluation of Kidney Function

The 24-hour creatinine clearance is the standard clinical technique for measuring kidney function; however, this measurement is cumbersome and inconvenient for patients. We hypothesized that a camera-based technetium-99m mercaptoacetyltriglycine (MAG3) clearance obtained simultaneously with a standard MAG3 scan would correlate well with the 24-hour creatinine clearance and could serve as a simple marker of kidney function. Data were obtained from a retrospective analysis of 28 patients with varying degrees of kidney dysfunction and 85 subjects evaluated for kidney donation. The MAG3 clearance was calculated using a camera-based technique without blood or urine sampling. The creatinine clearance was measured using the plasma creatinine and a 24-hour urine collection. The MAG3 and creatinine clearances were corrected for body surface area, and clearance values in healthy subjects and patients were compared using the paired Student's t test. The linear association between the MAG3 and creatinine clearances was expressed by Pearson's correlation coefficient. The mean MAG3 clearance in the potential kidney donors was 321 +/- 95 mL/min/1.73 m2 (95% CI, 171-546 mL/min/1.73 m2), significantly higher than the mean creatinine clearance of 152 +/- 51 mL/min/1.73 m2 (79-278 mL/min/1.73 m2, p < 0.001). The mean MAG3 clearance in patients was 153 +/- 70 mL/min/1.73 m2 (32-316 mL/min/1.73 m2) and was also significantly higher than the mean creatinine clearance of 74 +/- 36 mL/min/1.73 m2 (21-138 mL/min/1.73 m2, p < 0.001). The ratio of the mean creatinine clearance to the mean MAG3 clearance was essentially the same for volunteers and patients, 0.47 and 0.48, respectively. The Pearson's correlation between the MAG3 and creatinine clearances was 0.80 (0.72-0.86). The camera-based 99mTc-MAG3 clearance correlates well with the 24-hour creatinine clearance and can provide a simple and convenient index of kidney function.

Incidental DTPA and DMSA uptake during renal scanning in unknown bone metastases

We report a patient with DTPA and DMSA uptake on unsuspected bone metastases. He had severe pain due to grade 3 hydronephrosis of his left kidney. When Tc-99m DTPA and DMSA renal scanning were performed for preoperative evaluation, abnormal radiopharmaceutical uptake on the iliac area was noted. Pancreatic adenocarcinoma metastases to bone were subsequently defined. This patient is a very demonstrative case in respect of having all DTPA, DMSA and HDP uptakes in bone metastases. The type of the tumor has to be added to the list of extrarenal uptake of DTPA and DMSA as a rare cause.

A randomized study comparing an antireflux system with a direct ureteric anastomosis in patients with orthotopic ileal neobladders

To assess the benefit of an antireflux system in patients with orthotopic ileal neobladders, as there is controversy about whether reflux prevention offers any advantages. We conducted a randomized prospective study between January 2002 and March 2004, on 60 patients (53 men and seven women) with a mean (sd) age of 52.7 (7.3) years, who were candidates for orthotopic neobladders. Patients with comorbidities were excluded. Preoperative evaluation included intravenous urography (IVU), cystoscopic biopsy and radioisotope renography to evaluate the differential glomerular filtration rates (GFRs). Cases with normal kidneys and ureters, and with similar GFRs, were enrolled. Surgery comprised a standard radical cystectomy with pelvic lymphadenectomy. The ureters were randomized to either a direct anastomosis into a 5-cm ileal chimney on one side, or to be implanted using the antireflux serous-lined extramural tunnel on the contralateral side in the same patient. Regular follow-up included IVU and renography every 6 months in cancer-free patients. The mean (sd) follow-up was 23 (9.6) months. There was prolonged urinary leak from a refluxing ureter in one patient that was treated with a temporary percutaneous nephrostomy. Symptomatic pelvic collections required tube drainage in six cases. Six ureters developed early anastomotic strictures (one direct and five antirefluxing), and were treated with endoscopic ureterotomy in three and open revision in three. Serum creatinine levels were normal in all patients throughout the observation period. GFRs were similar in the two groups. The mean GFRs before surgery and at 6, 12, 18, and 24 months after cystectomy were: 55.1, 50.7, 49.4, 52.2 and 53.9 mL/min for the direct side; and 56.1, 53, 52.4, 53.2 and 50.4 mL/min for renal units with antirefluxing implantation. There was a significant deterioration of the GFRs due to anastomotic strictures, from 48.6 (6.7) mL/min before surgery to 31.8 (15.9) mL/min after the revision (P = 0.01). The antireflux procedures were associated with a higher incidence of anastomotic strictures than the direct methods and there was a significant deterioration of renal function after obstruction. The long-term follow-up data are awaited.

Tc-99m Ciprofloxacin (Infecton) in Abdominal Tuberculosis

Abstract: A 25-year-old man presented with a 2-month history of night fever, sweating, abdominal pain, and swelling. He tended livestock and frequently consumed unpasteurized milk. Examination revealed wasting and a “doughy” distended abdomen. Ultrasound showed matted loops of bowel and a pelvic fluid collection. An Infecton scan demonstrated abnormal abdominal uptake. A 35-year-old woman was admitted with fever, acute urinary retention, abdominal distension, and progressive weight loss. The patient was wasted and had gross ascites. The right kidney was not seen on a Tc-99m DTPA scan, and there was a scar in the left upper pole. Abnormal abdominal and pelvic activity was seen on Infecton scintigraphy. Both patients had negative chest radiographs and responded dramatically to antitubercular therapy.

Comparison of the Effectiveness of the Renogram, the Serial Renal Scan and the Diuretic Half Time according to the Renal Function for Interpreting a Diuretic DTPA Scan following Pyeloplasty

Purpose: The diuretic renal scan has been considered to be a good tool for evaluating the postoperative renal function in the patients with ureteropelvic junction obstruction (UPJO). We evaluated the diagnostic accuracy of the renogram, the serial renal scan and the diuretic half time according to the differential renal function (DRF) on the diuretic renal scan. Materials and Methods: We reviewed the diuretic renal scans of 27 pediatric patients (25 males and 2 females) who underwent pyeloplasty due to unilateral UPJO. Diuretic renal scanning was done using the TcDTPA (diethylenetriaminepentaacetic acid) standardized protocol. We compared the diagnostic accuracy of the renogram, the serial renal scan and the diuretic half time according to the DRF (group I: above 40%, group II: below 40%). Results: The mean age of the patients was 48.0±59.2 months (range: 2-210 months). The diuretic half time, renogram, serial renal scan and each combination demonstrated statistical significance for the interpretation of ureteral obstruction (generalized estimation equation, p=0.003). The interpretation of the diuretic renal scan was not affected by the DRF (McNemar test, p=0.598). The false positive rate and specificity of the renogram, serial renal scan and diuretic half time were 22.2%, 29.6%, 59.3% and 77.8%, 70.4%, 40.7%, respectively. In addition, the false positive rate and specificity of a combination of the diuretic half time and renogram, the diuretic half time and serial renal scan, the renogram and serial renal scan, the diuretic half time and renogram, and serial renal scan were 22.2%, 25.9%, 14.8%, 14.8%, and 77.8%, 74.1%, 85.2%, 85.2%, respectively. Conclusions: The diuretic half time, renogram and serial renal scan were individually correlated with the postoperative status of the UPJO. However, a combination of various factors of the renal scan should be considered for evaluating the postoperative status of UPJO. (Korean J Urol 2006;47:402-406)

The change of the split renal function before and after a nephrectomy using Tc-mercaptoacetyltriglycine (MAG3).

We examined the change in the renal function in the normal side kidney before and after a nephrectomy, by means of a newly developed diuretic renography technique utilizing Tc 99m-mercaptoacetyltriglycine (MAG3). Forty patients who underwent a nephrectomy were evaluated using MAG3 diuretic renography. We measured the effective renal plasma flow (ERPF) and Tmax time before and after a nephrectomy. The effects of the patient age and the preoperative ERPF of ill side kidney on the post operative ERPF were then assessed statistically. The ERPF increased by an average of 44.8 ml/min at 2 weeks after a nephrectomy, but it decreased by an average of 24.3 ml/min at 3 months after a nephrectomy. The Tmax time decreased by an average of 0.58 min at 2 weeks, but thereafter increased by an average of 0.58 min at 3 months after a nephrectomy. The correlation coefficient between the rate of increase in the ERPF and the patient age was 0.197. The rise of renal function in terms of ERPF and the Tmax time was observed at 2 weeks post-nephrectomy. However, this effect disappeared at 3 months post-nephrectomy. These data demonstrated that the rise in the renal function of the normal-side kidney in such patients was only temporary.

Assessment of regional kidney function may provide new clinical understanding and assist in treatment of children with prenatal hydronephrosis.

As calculated from a (99m)technetium (Tc)-mercaptoacetyltriglycine (MAG3) renogram, differential renal function is an important parameter affecting the clinical treatment of children with prenatal unilateral hydronephrosis. We determined whether value is potentially added by calculating a functional image from MAG3 renograms that represents proximal tubule ability to clear tracer from the blood, that is the MAG3 clearance image. MAG3 clearance image findings and differential renal function at presentation and followup in 59 nonsurgically and 42 surgically treated children with prenatally diagnosed unilateral hydronephrosis were retrospectively reviewed. All patients underwent at least 3 99mTc-MAG3 renograms. In the surgical and nonsurgical groups there was no significant difference in followup (p = 0.11), age at presentation (p = 0.98) or age at last visit (p = 0.97), whereas differential renal function was significantly different (p = 0.01). A large affected kidney with focal defects was the most frequent finding in each group, including kidneys with a normal differential renal function of 45% to 55%. In the nonsurgical group the most common observation was improvement in the MAG3 clearance image in 26 of 59 cases (44%) and stabilized differential renal function in 41 (70%). Postoperatively the MAG3 clearance image improved in 31 of 42 cases (74%) and differential renal function remained stable in 25 (60%), while no significant increase in differential renal function was noted at the last visit (p = 0.74). This study shows that it is possible to assess regional parenchymal function using the MAG3 clearance image in children with unilateral hydronephrosis. This information is available in addition to 99mTc-MAG3 information on the whole kidney, that is differential renal function. The majority of affected kidneys with normal differential renal function showed parenchymal defects, suggesting regional renal dysfunction. However, functional improvement on a regional basis occurred in each group of children during followup.

Contradictory Supranormal Function in Hydronephrotic Kidneys: Fact or Artifact on Pediatric MAG-3 Renal Scans?

Contradictory supranormal renal function (SRF) in unilateral hydronephrosis is a debatable subject resulting from the methodology of nuclear renography or the characteristics of the patient. In this study, we aimed to investigate the frequency and comparison of SRF with MAG-3 scans by 8 different technical analyses in pediatric hydronephrosis. We reviewed Tc-99m MAG-3 scans in 82 children with unilateral hydronephrosis (52 male, 30 female, mean age: 47.7 +/- 64.5 months). Of 82, 34 also had Tc-99m DMSA scans. Data were reprocessed with 4 different regions of background activity (subrenal, perirenal C-type, perirenal ring, and lateral) at 2 different time intervals (1-2 and 2-3 minute), and 8 different estimates of MAG-3 differential renal function (DRF) were obtained in 67 patients. SRF was defined as DRF greater than 55% in the hydronephrotic kidney. The routine processing protocol showed only 3 renal units with SRF, and all were on the right side (3.6%). After reprocessing, a total of 10 dilated kidneys had SRF in 1 or more of DRF estimates (5.2% of all estimations). These cases were significantly younger (8.1 +/- 6.7 vs. 42.5 +/- 52.5, P < 0.05) and had a larger renal area ratio (1.25 +/- .24 vs. 1.07 +/- .21, P < 0.05). There was no SRF with DMSA. In comparison between MAG-3 and DMSA DRF in 20 children who underwent both tests within 3 months, the best correlation was obtained when C-type correction was used for both agents at 2 time intervals (r: .86 and .84 for early and late time intervals, P < 0.00001, respectively). SRF in unilateral hydronephrosis is, at least, in part, technical in origin in this particular pediatric patient population with tubular immaturity (ie, physiological high background activity) and asymmetric kidney size.

Treatment of Emphysematous Pyelonephritis with Broad-spectrum Antibacterials and Percutaneous Renal Drainage: An Analysis of 10 Patients

This retrospective study was designed to determine the efficacy of broad-spectrum antibacterials combined with percutaneous renal drainage in the treatment of emphysematous pyelonephritis (EPN). From July 1992 to September 2002, 10 patients (nine females and one male) with EPN were managed at our institution. All patients had diabetes and presented with fever and chills, flank pain or tenderness, vomiting, and altered consciousness. The diagnosis of EPN was confirmed by the presence of intraparenchymal and/or perinephric gas in imaging studies (kidney-ureter-bladder film, sonogram, and/or computed tomography scan). Broad-spectrum antibacterial therapy, combined with percutaneous renal drainage, was started in all patients. Follow-up studies consisted of computed tomography scan and technetium-labeled diethylenetriaminepentaacetic acid (DTPA) radioisotope renography. The outcome was good in all patients. Three patients underwent delayed nephrectomy due to non-functioning of the involved kidney. The DTPA radioisotope renography results (glomerular filtration rate of the diseased kidney/ contralateral healthy kidney) were 0/57 mL/min, 2.7/68.1 mL/min and 3.7/63.9 mL/min. Combined broad-spectrum antibacterial therapy and percutaneous renal drainage is a safe and effective treatment for EPN, especially in high-risk patients for whom nephrectomy under general anesthesia is not feasible.

Is screening ultrasound of the urinary tract indicated in infants with hypertrophic pyloric stenosis?

Few retrospective studies have evaluated infants with hypertrophic pyloric stenosis (HPS) for associated urological anomalies. They have led to contradictory conclusions. The aim of this study was to evaluate the incidence of urinary tract anomalies in infants with HPS and to establish the clinical significance of this association. One hundred and twenty-two infants (100 boys) who underwent pyloromyotomy between 1992 and 2002 were prospectively evaluated. Screening ultrasound (Us) of the urinary tract was performed in 107 infants, while 15 did not attend their ultrasound appointment. Renal ultrasound was abnormal in 4 (4%) of 107 screened patients with HPS. Three patients were found to have mild hydronephrosis and, in one patient, a small, normal kidney was detected. Two patients with hydronephrosis had Us follow-up and the third patient underwent Tc-99 mercaptoacetyl triglycine (MAG 3) scan. In all three patients, the hydronephrosis resolved completely on follow-up scan. The incidence of abnormal renal ultrasound in children with HPS is similar to the reported incidence of 3-6% determined with routine ultrasound screening of healthy newborns. The abnormalities detected were not clinically relevant and did not require surgical intervention. We do not recommend screening of the urinary tract in infants with HPS.

A large renal pelvic diverticulum, presenting incomplete excretion during tc-99m mag-3 scintigraphy and tracer accumulation on tc-99m dmsa scintigraphy; a case report

This case report illustrates the dynamic and static renal scintigraphic images of a patient with an unusual large diverticulum of the renal pelvis. The initial diagnosis by intravenous pyelography (IVP) and ultrasonographic (US) examination was a renal pelvic diverticulum of the left kidney, and the patient was referred to the nuclear medicine department for exploration of the effect of the pelvic diverticulum on renal functions. We performed dynamic renal scintigraphy with technetium-99m (Tc-99m) labeled mercaptoacetyl triglycine (MAG-3) and static renal scintigraphy with Tc-99m labeled dimercaptosuccinic acid (DMSA). In dynamic renal scintigraphy, bilaterally normal concentration function was observed. While right kidney excretion function was normal, an incomplete excretion pattern was seen on the left side. Complete urinary flow obstruction occurred approximately at the 10th minute of the acquisition, which did not seem to respond to the i.v. furosemide application. However, when only the renal cortex was included in the region of interest, the obstructive pattern disappeared. In static renal scintigraphy, a large renal pelvic diverticulum localized antero-medially was clearly visualized in the left-anterior oblique projection, most probably due to accumulation of radiopharmaceutical inside it. This case showed that a renal pelvic diverticulum should be thought of when an incomplete excretion pattern is seen on dynamic renal scintigraphy. Using only a cortical region of interest may also help to distinguish other types of obstructive pattern from diverticulum. Additionally, Tc-99m DMSA scintigraphy may show diverticulum localization with antero-oblique projections in addition to routine projections.

Recoverability of renal function after treatment of adult patients with unilateral obstructive uropathy and normal contralateral kidney: A prospective study

Objectives To study the methods of prediction of recoverability of renal function after the treatment of adult patients with unilateral obstructive uropathy and a normal contralateral kidney. Methods This prospective study included 91 consecutive adult patients with the diagnosis of unilateral obstructive uropathy and a normal contralateral kidney. All patients had a nonequivocal cause of obstruction that was successfully relieved after treatment. All patients underwent plain abdominal x-ray, gray-scale ultrasonography, Doppler ultrasonography, excretory urography, and technetium-99m-diethylenetriamine pentaacetic acid radioisotope renography before and after treatment. Patients were seen regularly at 3, 6, and 12 months for a mean duration of 13 ± 6 months (range 6 to 36). At each visit, ultrasonography and renography were performed, and excretory urography was performed at least once during follow-up. Several renographic and ultrasound parameters were studied before and after treatment to evaluate their value in predicting the recoverability of renal function. The difference between the selective renographic glomerular filtration rate (GFR) of the ipsilateral kidney before treatment and its mean value after treatment was considered as the reference variable to which all other variables were compared. All prognostic parameters were evaluated by both univariate and multivariate analyses. Results On univariate analysis, the factors that significantly affected the recoverability of renal function after the relief of obstruction included preoperative renographic GFR, renal perfusion, parenchymal thickness, parenchymal echogenicity, corticomedullary differentiation, reduction of the renal resistive index of the corresponding kidney, and compensatory hypertrophy of the contralateral normal kidney. However, using multivariate analysis, only the preoperative selective renographic GFR and renal perfusion of the corresponding kidney sustained their statistical significance as independent factors affecting renal functional recovery. A preoperative GFR value of 10 mL/min/1.73 m 2 was estimated as the cutoff point that can determine the best prediction of stabilization or improvement of renal function after the relief of obstruction. Conclusions Preoperative renographic clearance and perfusion of the corresponding kidney were the only predictors of recoverability of unilateral renal obstruction. Kidneys with a renographic GFR of less than 10 mL/min/1.73 m 2 were irreversibly damaged. Improvement or stabilization of function can be expected after relief of obstruction of kidneys with a renographic GFR of 10 mL/min/1.73 m 2 or greater.

Application of renal doppler sonography in the diagnosis of obstructive uropathy in patients with spinal cord injury

Tseng F-F, Bih L-I, Tsai S-J, Huang Y-H, Wu Y-T, Chen Y-Z. Application of renal Doppler sonography in the diagnosis of obstructive uropathy in patients with spinal cord injury. Arch Phys Med Rehabil 2004;85:1509–12. Objectives To assess renal resistive index (RI) changes in patients with spinal cord injury (SCI) who have obstructive uropathy and to determine if an RI of 0.7 or more is useful in identifying such patients. Design Prospective cross-sectional study. Setting Rehabilitation hospital affiliated with a medical university. Participants A convenience sample of 99 kidneys of 51 SCI patients (38 men, 13 women; mean age, 38.8±14.0y) with neuropathic bladder dysfunction. Interventions Ultrasonic examination to assess the degree of hydronephrosis, Doppler sonography to calculate renal vascular RIs, and radioisotopic renography to assess renal function and to determine excretory curves. Kidneys were assigned to control or obstructive uropathy groups, and RIs were compared for statistical significance (Student t test) and to assess whether an RI of 0.7 is a distinguishing criterion. Main Outcome Measures RI and sensitivity. Results Average RIs were .58±.07 in the control group (71 kidneys) and .65±.08 in the uropathy group (28 kidneys) ( P<.001). The sensitivity of using an RI of 0.7 or more to identify patients with obstructive uropathy was 39%. The c statistic of the receiver operating characteristic curve was .72. Conclusions RIs increased in SCI patients with obstructive uropathy. In patients with SCI, urinary findings fit the chronic partial obstruction pattern. A renal RI of 0.7 or more was a poor indicator of obstructive uropathy in such patients.

Renal Artery Stenting for Renal Artery Stenosis: Interventional Approach and Initial Clinical Results

Background. Significant renal artery stenosis is being increasingly diagnosed and interventional cardiologists are taking on the unfamiliar role of deploying renal stents. We describe our technique for renal artery stenting using techniques and equipment similar to that used in coronary stenting and present early results. Methods. Thirty-two patients with significant renal artery stenosis (diameter stenosis 60–95%) and difficult to control hypertension or renal impairment were referred for renal stenting. Renal DTPA scans were performed before intervention. All the procedures were attempted from the femoral artery approach using guides, low profile wires and balloon catheters similar to those used for coronary work. The lowest profile renal or coronary stents were deployed using a monorail technique. Results. Atherosclerosis was the cause of the renal artery stenosis in 31 patients. Stents were successfully deployed in 30 of these patients (97%). One patient required a second procedure from the brachial artery approach. An additional patient with fibromuscular dysplasia underwent angioplasty only. Angiographic diameter stenosis was reduced from a mean of 79 to 1%. Translesional mean pressure gradients were reduced from 22 to 1 mmHg. There were no major procedural or in-hospital complications. Anti-hypertensive drugs were reduced from a mean of 3 prior to stenting to 0.7 at discharge. Renal DTPA scans were a poor predictor of severity of stenosis. Renal DTPA scans suggested functionally significant renal artery stenosis in only 48% of patients but the clinical responses suggested that this was an underestimate. Conclusions. Stenting of renal arteries using coronary like techniques and equipment results in a high rate of procedural success and good early clinical outcomes.

Ureteropelvic junction obstruction: does CT angiography allow better selection of therapeutic modalities and better patient outcome?

To determine whether preoperative helical CT angiography (CTA) with three-dimensional (3D) reconstructed images improves outcome in patients with ureteropelvic junction obstruction (UPJO) by identifying crossing vessels that may lead to surgical failure. Twenty-five patients with UPJO underwent imaging with CTA to identify crossing vessels. Patients with crossing vessels or severe hydronephrosis underwent laparoscopic dismembered pyeloplasty. In the absence of crossing vessels, and with >25% renal function on MAG-3 scan, the patient underwent an endopyelotomy. Procedures were assessed as successful by resolution of patient symptoms as well as relief of obstruction on renal scintography. Twenty-seven procedures (14 laparoscopic dismembered pyeloplasties [9 in the setting of a crossing vessel], 11 ureteroscopic endopyelotomies, and two antegrade endopyelotomy procedures) were performed. Follow-up ranged from 2.4 to 40 months (mean 21.6 months). Twenty-three of the primary procedures (92.0%) were successful. Primary laparoscopic pyeloplasty was successful in 100% of patients, while primary endopyelotomy had a success rate of 83.3%. Both secondary procedures were successful rendering the patients unobstructed and pain free. No complications occurred. The sensitivity and specificity of CTA in determining crossing vessels was 78% and 40%, respectively. Helical CT angiography with 3D reconstructed images provides valuable preoperative information in patients with UPJO scheduled for surgical intervention. This study may be used in selecting patients for proper operative intervention according to the anatomy of crossing vessels to attain high treatment success rates.

Synthesis, radiolabeling and in vitro and in vivo characterization of a technetium-99m-labeled alpha-M2 peptide as a tumor imaging agent.

In an effort to develop a peptide-based radiopharmaceutical for the detection of breast cancer, we have prepared an analog of alphaM2 peptide, modified to incorporate an N3S chelate system. Mercaptoacetyltriglycine (MAG)(3)-derivatized alphaM2 peptide was prepared by solid-phase synthesis and radiolabeled with (99m)Tc by an exchange method. In vitro cell-binding on human breast cancer cell lines, MDA-MB-231 and MCF-7, indicated the affinity and specificity of (99m)Tc-MAG(3)-alphaM2 toward breast cancer cells. Additionally, the radiolabeled peptide showed rapid internalization into human breast cancer cells. In vivo biodistribution in mice showed that the radiolabeled peptide cleared rapidly from the blood and most non-target tissues and was excreted significantly via the kidneys. Uptake of (99m)Tc-MAG(3)-alphaM2 in the tumor was moderate. The radiochemical and in vitro and in vivo characterization indicates that the radiolabeled peptide has certain favorable properties and it might be a useful radiopharmaceutical for the detection of breast cancer in vivo.

Laparoscopic partial nephrectomy with temporary arterial occlusion: description of technique and renal functional outcomes

Objectives To report our laparoscopic partial nephrectomy experience and the impact of temporary arterial occlusion during laparoscopic partial nephrectomy on postoperative renal function. Laparoscopic partial nephrectomy is increasingly popular but remains technically challenging. Methods Laparoscopic partial nephrectomy was performed in 27 patients, with arterial occlusion in 15 cases. Postoperative renal function was evaluated with serum creatinine in all patients and postoperative technetium-99m mercaptoacetyl triglycine renal scans in a subset of patients after arterial occlusion. Results The group with arterial occlusion (n = 15) did not differ from those without arterial occlusion (n = 12) with respect to age, body mass index, American Society of Anesthesiologists score, lesion size, operative time, blood loss, or complications. In patients undergoing arterial occlusion, the mean warm ischemia time was 43 ± 10 minutes (range 25 to 65). The preoperative and postoperative serum creatinine levels were unchanged in patients with (1.07 ± 0.4 to 1.15 ± 0.4 ng/dL; P = 0.24) and without (0.96 ± 0.22 to 1.07 ± 0.27 ng/dL; P = 0.14) arterial occlusion. The tumor size on imaging correlated with postoperative serum creatinine ( r 2 = 0.450, P = 0.04). Nuclear renography was performed in 9 patients (60%) after renal artery occlusion. The mean differential renal function of the operated kidney (49%) was similar to that of the contralateral kidney (51%) and was not associated with warm ischemic time or tumor size. Conclusions Temporary arterial occlusion during laparoscopic partial nephrectomy does not appear to affect short-term renal function adversely. We believe that this technique can be safely performed when significant bleeding or entry into the collecting system is anticipated. Additional study is warranted to identify the maximal time of warm ischemia and ways to reduce potential renal injury.

Open Pyeloplasty in Children: Experience with an Improved Stenting Technique

Objective: To describe the use of an alternative and improved nephrostostent in open pyeloplasty procedures. Materials and Methods: A series of 27 consecutive patients (between 4 months and 14 years of age) undergoing an open pyeloplasty procedure had their urinary system drained via a nephrostostent which passes from the ureteric anastomosis to the skin and which unlike other described nephrostostents does not cross the vesico-ureteric junction. All children received an ultrasound and MAG3 scan 3 months post-operatively and were followed up for 18–24 months. Results: The use of this stent was associated with no serious complications. There was a decreased incidence of vesico-ureteric reflux, post-operative urinary tract infection and stent displacement compared to previously described methods of drainage. Conclusion: This method of open pyeloplasty drainage, which has not been described before, could be associated with fewer complications than existing stenting techniques.

Revisiting the role of nephrectomy for advanced renovascular disease

Background Despite the advances in antihypertensive therapy and renal revascularization, there remains a group of patients in whom renovascular disease leads to renal atrophy and treatment-resistant hypertension. Methods We performed an observational cohort study in which we reviewed blood pressures, renal function, and predictors of response in 74 patients who underwent nephrectomy of a small kidney for uncontrolled hypertension between 1990 and 2000. Results The median age of the patients was 65 years; 43 (58%) were women. Thirty-five patients (47%) underwent nephrectomy as part of combined revascularization of the contralateral kidney. Associated atherosclerotic diseases were common (28% to 49%), as were prior renal revascularization (21 [28%]) and hypertensive urgency/emergencies (23 [31%]). The mean (± SD) long axis of the affected kidney was 8 ± 2 cm, and the mean function of the kidney (based on radioisotope renography) was 12% ± 11% of total renal function. The average systolic blood pressure fell from 168 ± 19 mm Hg to 136 ± 18 mm Hg ( P <0.0001) and diastolic blood pressure declined from 88 ± 10 mm Hg to 76 ± 9 mm Hg ( P <0.0001) at the most recent available clinic visit (mean follow-up, 4.1 ± 2.6 years). In addition, the number of antihypertensive medications decreased from 3.2 ± 1.1 to 2.2 ± 1.5 ( P <0.0001). Renal function remained stable. Results were similar (preoperative blood pressure of 165/88 mm Hg taking three medications to 137/77 mm Hg taking two medications) among the 39 patients who had a nephrectomy without contralateral revascularization. Conclusion Our results suggest that in selected patients with resistant hypertension and renal artery disease that has resulted in atrophic kidneys with reduced function, nephrectomy can improve blood pressure control without further loss in overall renal function.

Vesicoureteral reflux causing misinterpretation of a Tc-99m DTPA scan.

The authors examined a 10-year-old girl to determine the functional status of an atrophic kidney resulting from chronic pyelonephritis. A Tc-99m DTPA scan revealed an atrophic right kidney with an 11.8% split renal function. On DMSA images, severe cortical loss was visualized in the right kidney, and the right relative function was 2%. Vesicoureteric reflux was thought to be a possible cause, leading to misinterpretation of the DTPA study. Direct radionuclide ureterocystography showed severe vesicoureteric reflux on the right side. This case indicates that DTPA and DMSA studies are complementary in measurements of the differential function of an atrophic kidney. If any uncertainty exists, additional studies should be performed to identify the underlying cause.