• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.239-247
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• 1993

Differentiating the various causes of hydronephrosis from that of obstruction can be very difficult. The decision-making process for those instances of urinary tract dilatation that require surgical correction and those that do not is based in part on the findings of diuresis renography. The methodology for performing this test has differed among nuclear medicine practitioners and the surgical findings are occasionally discrepant from the diuretic renogram interpretation. Consequently we made an automatic computer software program that calculates the slope of the response curve. The quantitative indices, such as the injection and response t1/2 by linear-fitting and monoexponential-fitting, were compared with the visual assessment of the diuretic cinerenography and clinical outcome in 50 children (62 kidneys) with ureteropelvic junction obstruction. Pooled diuresis renogram data indicated that: (1) Visual evaluation of the diuretic cinerenography is a sensitive (87%, 54/62) tool to differentiate obstruction in suspected ureteropelvic junction obstruction. (2) The cut-off value (maximum washout t1/2 with non-obstruction) of injection and response t1/2 by linear-fitting were 40 min. (3) The sensitivity and specificity using injection and response t1/2 by linear-fitting for obstruction were 89%(23/26) and 100%(30/30), respectively. (4) Response t1/2 as well as injection t1/2 by monoexponential-fitting do not stratify children with possible ureteropelivic junction obstruction. In conclusion, quantitative assessment of diuretic renography as well as visual assessment of diuretic cinerenography correlate well with surgical and clinical outcome of suspected ureteropelvic junction obstruction.

• Childhood Kidney Diseases
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• v.19 no.1
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• pp.14-22
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• 2015

Renal scintigraphic methods, which are physiologic and minimally invasive, have played important role in the management of various renal diseases in children, providing sensitive tool for early detection of disease even before structural changes become prominent and giving valuable functional and anatomical information to aid medical decision makings in the treatment and follow-up of patients. This review article focuses on the concept and advantages of renal scintigraphy in pediatric patients with various urologic diseases.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.75-84
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• 1994

The need for assessment of ureteric function in the patient with an obviousely dilated ureter has increased particularly with the added spectrum of asymptomatic patients presenting with hydrone-phrosis and hydroureter on antenatal and perinatal ultrasound. To assess the influence of ureteral status on kidney washout during $^{99m}Tc$-DTPA diuretic renography, ureteral images were reviewed in 80 children referred for hydronephrosis. A scintigraphically abnormal ureter was defined as an intense and continuous image of > 10 min during diuretic renography. Out of them, a total of 16 nephroureteral systems in 12 children with scintigraphically abnormal ureter were analyzed. A diuretic washout index using response half time (t1/2) by linear fitting after lasix injection, was determined on renal (Kt1/2) and ureteral (Ut1/2) curves (diuretic renogram vs. diuretic ureterogram). Diuretic ureterogram curve patterns corresponding to normal (type I), obstructive (II) and non-obstructive (III) cases were described. Compared with X-ray data, diuretic renography was highly sensitive (88%) and specific (99%) for detecting any ureteral abnormality. Despite an obstructive Kt1/2 (>20 min), no patient with an abnormal ureter underwent therapy at the ureteropelvic junction because the hydronephrosis regressed after surgery at the lower level. Our data indicate that the abnormal ureter findings during diuretic renography have to be recognized before therapy for children with hydeonephrosis.

• The Korean Journal of Nuclear Medicine
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• v.36 no.5
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• pp.306-313
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• 2002

Purpose: Diuretic renography (DR) can be false negative in patients with upper urinary tract obstruction due to low compliance of the renal pelvis. Delayed parenchymal transit (DPT) may be a valuable sign in case of false negative DR. We compared the diagnostic values of DR and DPT during Tc-99m MAG3 diuretic scan in adults with suspected unilateral obstructive uropathy. Materials and Methods: Fifty-four patients(male:female=30:24, age: $40.7{\pm}15.5$ yrs) who underwent Tc-99m MAG3 diuretic scan due to suspicious unilateral obstructive uropathy were analyzed. DR with a $T_{1/2}\;of\;>\;15min$ was considered as positive for obstruction. DPT was considered to be present when there was delayed appearance of radioactivity in the renal pelvis and prolonged retention of radioactivity in the renal parenchyma. The renal area ratio was defined as the ratio of pixel number of hydronephrotic kidney over that of normal contralateral at $1{\sim}2min$ images. Definition of obstruction was improved hydronephrosis after intervention, or aggravated hydronephrosis without intervention. Non-obstruction was defined as unchanged hydronephrosis over 6 months. Results: Twenty-six renal units had obstruction and 28 no obstruction. The sensitivities of DR and DPT were 69% (18/26) and 50% (13/26) respectively. Two renal units with DPT but negative DR showed the renal area ratio of <1.1. Among the 20 obstructive renal units with DPT or positive DR, 13 with DPT had lower renal area ratio than 7 renal units without DPT ($0.97{\pm}0.20\;vs\;1.30{\pm}0.41,\;p<0.05$). Differential renal function was not significantly different between these groups. DPT correctly diagnosed all renal units with non-obstruction (specificity 100%), while the specificity of DR was 89% (25/28). Conclusion: DPT during Tc-99m MAG3 diuretic scan may be a valuable sign in diagnosing urinary obstruction especially in patients with false negative DR and early HN.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.57-64
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• 1999

Purpose: The purpose of this study was to evaluate the accuracy of Tc-99m DTPA diuretic renal scans in children with dilated upper urinary tract. Materials and Methods: We reviewed diuretic renal scans of 14 pediatric patients (age range: 3 days to 4 years) with unilateral hydronephrosis diagnosed by ultrasonography. Diuretic renal scan was done using Tc-99m DTPA and standardized protocol. In 3 neonates, diuretic renal scans were performed within 1 week and 3-7 months after birth. Results: Six patients required Pyeloplasty and eight were managed conservatively. All 6 patients requiring Pyeloplasty were diagnosed as having ureteropelvic junction obstruction in the diuretic renal scan. In these 6 patients, post-operative renal scans at 3-12 months after surgery were converted to nonobstructive pattern in 5 and a nonfunctioning pattern in 1. In 3 patients who underwent diuretic renal scan within 1 week after birth, nonobstructive patterns of initial scan were converted to obstructive patterns in the follow-up scan. However, all patients with nonobstructive diuretic renal scans performed after the neonatal period did well on serial ultrasonography and showed favorable clinical outcome without progression to obstruction. Conclusion: Tc-99m DTPA diuretic renal scan with standardized protocol is useful in assessing suspected ureteropelvic junction obstruction in children as an initial diagnostic or post-operative follow-up modality. Nonobstructive or indeterminate scan results in the neonatal period requires follow-up scan to monitor development of the obstructive pattern.

• The Korean Journal of Nuclear Medicine
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• v.17 no.2
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• pp.57-62
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• 1983

Diuretic renal scan, a modified method of conventional radionuclide renography by administration of intravenous furosemide was performed in 54 patients with suspected urinary tract obstruction. Two showed normal responses, 41 showed increased washout patterns, and the remainder 15 revealed no changes in response to the furosemide administration. IVP was done in 34 patients. In comparision to the diuretic renal scan, the following results were obtained. 1) Patients with normal results by the scan, showed normal IVP findings also. 2) 10 patients who showed delayed excretory patterns not influenced by the diuretics administration. 9 patients revealed obstructive lesions and hydronephrotic changes, and CPN was diagnosed for the remainder one and the one patient without obstruction was diagnosed as chronic pyelonephritis. 3) 22 patients showed positive results to the diuretics. Among them 10 patients had positive results in IVP. but, were not related to the speed of decrement of the renal activity after the furosemide administration.

• Childhood Kidney Diseases
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• v.4 no.1
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• pp.57-62
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• 2000

Purpose: Unilateral ureteropelvic junction obstruction with high grade of hydronephrosis an obstructed diuretic renogram but good differential renal function were studied to evaluate the natural history of untreated obstruction. Materials and Methods: During the last three years, we encountered 18 kidneys with hydronephrosis detected on prenatal ultrasound. In all these patients other urologic abnormalities were excluded by voiding cystourethrography and other radiological studies. Diuretic renography was initially performed at an age ranging from 2 weeks to 4 weeks. Five had high degree of hydronephrosis and obstructed diuretic renogram despite good relative renal function. Periodic urine examination, ultrasonography and diuretic renogram were done at regular intervals. Results: We have followed 5 neonates with unilateral hydronephrosis and suspected ureteropelvic junction obstruction with noroperative treatment for 15 months. During followup, percentage and relative renal function were maintained in all patients and hydronephrosis improved. Obstructive patterns on diuretic renogram were variable. Conclusions: These findings help to define the natural history of untreated good functioning hydronephrotic kidneys. Many newborn kidneys with severe hydronephrosis are not obstructed despite even high grade of hydronephrosis and obstructed diuretic renogram.

• Childhood Kidney Diseases
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• v.19 no.1
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• pp.8-13
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• 2015

Antenatal hydronephrosis (ANH) is one of the most common abnormal findings detected on prenatal ultrasound (US), and it has been reported in 1-5% of all pregnancies. The likelihood of significant postnatal pathologic abnormality in the urinary tract correlates with the degree of anterior-posterior diameter (APD) according to the gestational age. Detection of urologic anomalies prenatally permits fetal interventions that avoid complications in rare cases of bladder outlet obstruction with oligohydramnios even though their final benefits still remain controversial. There is no clear consensus on the extent and mode of postnatal imaging after a diagnosis of ANH. US is the mainstay of the postnatal evaluation and helps guide further testing with voiding cystourethrography (VCUG) and diuretic renography. Although most algorithms continue to recommend generous VCUG for identification of lower urinary tract anomalies, VCUG may be safely reserved for high grade ANH cases or any grade of ANH with dilated distal ureter without increasing the risk of urinary tract infection (UTI). There are conflicting studies about efficacy of postnatal prophylactic antibiotics. It still seems reasonable to consider use of a prophylactic antibiotic to prevent infant UTIs in high-risk populations, such as females and uncircumcised males with high grades of hydronephrosis, hydroureteronephrosis, or vesicouretral reflux.

• Clinical and Experimental Pediatrics
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• v.45 no.2
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• pp.223-231
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• 2002

Purpose : We review our experience with pyeloplasty for unilateral ureteropelvic junction obstruction of moderate to severe hydronephrosis observed by prenatal ultrasonography to assess the appropriate timing of operation for recovery of renal function and obstruction. Methods : We retrospectively reviewed the records of the total 28 patients who underwent pyeloplasty between 1995 and 2001 at Asan Medical Center. We compared pre and postoperative differentials in renal function and diuretic renogram as measured by technetium-99m-mercaptoacetyl-triglycerine scan and the degree of hydronephrosis by renal ultrasonography. Results : In all 28 patients postoperative follow-up renal ultrasonography revealed significant improvement in hydronephrosis. In 10 poorly functioning hydronephrotic kidneys in which relative renal function function was less than 35%, renal function was improved postoperatively in 3 cases, but not improved in 7 cases. In all 28 patients postoperative follow-up diuretic renogram revealed significant improvement. Conclusion : We believe that the early pyeloplasty should be considered when ultrasonography and diuretic renography suggest obstruction because renal function does not improve significantly after pyeloplasty over preoperative value.

• Childhood Kidney Diseases
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• v.2 no.2
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• pp.161-168
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• 1998

Purpose : Lots of congenital anomalies of urinary tract including hydronephrosis are detected in fetus and neworn by popular use of prenatal ultrasonography. But there are little data available in Korea about natural course of hydronephrosis diagnosed antenatally by ultrasonography. So we intended to help management of these patients by analizing the follow up data of the neonates with hydronephrosis diagnosed antenatally. Methods : We evaluated 22 patients with neonatal hydronephrosis(33 renal units) who were diagnosed prenatally and confirmed postnatally. Especially patients with suspected ureteropelvic junction obstruction were followed regulary with renal ultrasonography and diuretic renography for 8-24 months. Results : 1) The etiologies of neonatal hydronephrosis diagnosed prenatally were suspected ureteropelvic junction obstruction($69.9\%$), vesicoureteral reflux($15.1\%$), primary megaureter($3.0\%$), double ureter with ureterocele($3.0\%$), ureteral stricture($3.0\%$), multicystic dysplastic kidney(3.0$\%$), and ureterovesical junction obstruction(3.0$\%$). 2) The follow up results of 23 renal units of suspected ureteropelvic junction obsruction: Except 4 renal units with palpable abdominal mass, of the remained 19 renal units, 14 units($73.6\%$) were improved spontaneously, 3 units($15.7\%$) remained stable, only2 units($10.5\%$) were aggravated. Conclusion : We concluded that in most cases of hydronephrosis there is no need for immediate surgery, and that nonoperative approach, using serial ultrasonography and diuretic renogram, is safe management of neonatal hydronephrosis diagnosed anteratally.