|Year : 2018 | Volume
| Issue : 1 | Page : 39-42
Comparison of the F+20 and F-15 diuresis technetium-99m diethylenetriaminepentacetate renography protocols for diagnosis of ureteropelvic junction obstruction in adult patients with hydronephrosis
Majhi Tapas Kumar, Singh Hanuwant
Department of Urology, Nil Ratan Sircar Medical College and Hospital, West Bengal, India
|Date of Web Publication||16-Jan-2018|
Dr. Singh Hanuwant
Department of Urology, Nil Ratan Sircar Medical College and Hospital, 138, AJC Bose Road, Kolkata - 700 014, West Bengal
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Hydronephrosis (HDN) in adults is a common presentation and may be due to congenital ureteropelvic junction obstruction. Diuresis renography is the method of choice for differentiating a dilated unobstructed urinary system from a true obstruction. The aim of this study was to compare the F+20 protocol with F-15 protocol and see whether this new protocol can reduce inconclusive results. Materials and Methods: It was a prospective, comparative study included 51 adult patients of primary HDN. Each patient underwent both F+20 and F-15 diuretic Technetium-99m diethylenetriaminepentacetate (Tc-DTPA) renography protocol studies. The results of diuretic Tc-DTPA renography studied in terms of obstructive, nonobstructive, or equivocal. Results: A total 60 renal units (RU) with HDN were included in this study. The mean age of patients was 25.25 years. 36 RU presented with specific symptoms and 24 RU with vague symptoms or diagnosed incidentally. The equivocal results were significantly lower in F-15 protocol than F+20 protocol. The equivocal results in F+20 protocol were significantly higher with incidentally diagnosed HDN and patients presented with vague symptoms. Most of the equivocal results of F+20 protocol were converted into either obstructive or nonobstructive by the F-15 protocol. Conclusion: The F-15 diuretic renogram protocol was associated with significantly less equivocal results than F+20 protocol. Moreover, F-15 protocol allowed clarification in cases of equivocal results of F+20 protocol. Therefore, we suggest the F-15 diuresis protocol as a single test for confirmation or exclusion of obstruction especially in the adult patient of HDN presented with vague symptoms or diagnosed incidentally.
Keywords: Adult, diuresis, F+20, F-15, hydronephrosis, protocol, Technetium-99m diethylenetriaminepentacetate renography, ureteropelvic junction obstruction
|How to cite this article:|
Kumar MT, Hanuwant S. Comparison of the F+20 and F-15 diuresis technetium-99m diethylenetriaminepentacetate renography protocols for diagnosis of ureteropelvic junction obstruction in adult patients with hydronephrosis. Indian J Nucl Med 2018;33:39-42
|How to cite this URL:|
Kumar MT, Hanuwant S. Comparison of the F+20 and F-15 diuresis technetium-99m diethylenetriaminepentacetate renography protocols for diagnosis of ureteropelvic junction obstruction in adult patients with hydronephrosis. Indian J Nucl Med [serial online] 2018 [cited 2019 Dec 8];33:39-42. Available from: http://www.ijnm.in/text.asp?2018/33/1/39/223241
| Introduction|| |
Hydronephrosis (HDN) in adults is a common presentation and may be due to congenital ureteropelvic junction obstruction. The patient presentation may vary from incidental diagnosis on routine ultrasound; or with vague symptoms to frank symptoms of obstruction. Diuresis renography is the method of choice for differentiating a dilated unobstructed urinary system from a true obstruction. In traditional F+20 diuresis Technetium-99m diethylenetriaminepentacetate (Tc-DTPA) renography protocol, many hydronephrotic kidneys show inconclusive results. This poses difficulty in management decision, especially in asymptomatic patients and patients with vague symptoms. The aim of this study was to compare the F+20 protocol with F-15 protocol and see whether this new protocol can reduce inconclusive results.
| Materials and Methods|| |
It was a prospective, comparative study conducted in a tertiary care center after the institute ethical committee clearance. Informed consent was taken from all patients. Adult patients more than 18 years of age presenting with primary HDN in ultrasound were included in the study. The patients with very poor renal function (glomerular filtration rate [GFR] <15 ml/min), secondary ureteropelvic junction obstruction, patients with dilated ureter, lower urinary symptoms, pregnancy and delivery in the last 2 years, patients having any contraindications to diuretic therapy, and pregnant and lactating women were excluded from the study. In the study period of 1½ years (January 2014–June 2015), totaly 64 adult patients with primary HDN reported to our institute. Thirteen patients were excluded from the study because of very poor function of hydronephrotic renal unit (RU) and 51 patients (21 males and 30 females) were studied in this study.
Each patient underwent both F+20 and F-15 diuresis Tc-DTPA renography protocol studies. The time interval between two studies was kept 2 days because the half-life of the radioactive Technetium-99 m is 6 h, and after 2 days, it leaves no significant residual radioactivity. All the studies were done at single nuclear medicine center with identical equipment and analyzed by the single expert analyzer. Adequate hydration was vital to ensure good diuresis. Patients were asked to void before the study. A typical adult dose of 50–120 MBq Tc-DTPA radiopharmaceutical agent was carefully injected intravenously to avoid local extravasation. The patients were asked to void at the end of the procedure (to minimize radiation to the bladder). The amount of radiation exposure in this study is roughly equivalent to that which received from natural background radiation in about 6 months.
An intravenous bolus of furosemide (40 mg) was used as diuretic. The two protocols were identical, except for the time of injection of furosemide. In the conventional F+20 diuresis Tc-DTPA renography protocol, furosemide was administered 20 min after injection of the radiopharmaceutical. The study was continued for at least 20 min following furosemide injection. In the modified F-15 diuresis renography protocol, furosemide was given 15 min before radiopharmaceutical injection.
Diuretic renography is a noninvasive test and based on a high endogenous urine flow rate stimulated by the administration of furosemide. The diagnosis of obstruction is based on an abnormally slow washout of the tracer from a dilated collecting system. If the collecting system is only dilated but nonobstructed, the tracer will wash out rapidly. It can also quantitate rate of washout by measuring the T1/2 (time for the activity in the collecting system to fall to 50% of its original value). Prompt clearance of the tracer from the renal pelvis with a T1/2 <10 min is a normal response and excludes obstruction. Values between 10 and 20 min are often considered to be equivocal, and a T1/2 >20 min is considered for obstruction.
The results of diuretic Tc-DTPA renography studied in terms of the curve pattern, GFR, split renal function, and diuretic T1/2 measurement, and the interpretation was done accordingly.
Continuous data were expressed as mean (±SD). Comparative analyses were done by Chi-square test and Fisher's exact tests. IBM SPSS Statistics v20.0 software (International Business Machines Corp.2011 New Orchard Road Armonk, New York 10504) was used for statistical analysis. P < 0.05 was considered statistically significant.
| Results|| |
A total 60 RU with HDN (42 patients with unilateral and 9 patients with bilateral HDN) were included in this study. The mean age of patients was 25.25 ± 5.2 years. Thirty-six (60%) RU presented with specific symptoms and 24 (40%) RU with vague symptoms or diagnosed incidentally. The equivocal results were significantly lower in F-15 protocol than F+20 protocol [Table 1]. The equivocal results in F+20 protocol were significantly higher with incidentally diagnosed HDN and patients presented with vague symptoms [Table 2]. Most of the equivocal results of F+20 protocol were conclusively categorized into either obstructive or nonobstructive by F-15 protocol [Table 3].
|Table 1: Comparison of the results of F+20 and F-15 protocols: Significantly low equivocal results in F-15 protocol|
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|Table 2: Patient presentation and results of F+20 protocol: The equivocal results significantly higher with vague symptoms or incidental diagnosis|
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| Discussion|| |
Not all patients demonstrating HDN require intervention, but HDN which is secondary to urinary tract obstruction, if untreated, may lead to progressive renal damage. Hence, the results of diuretic renogram are vital because inconclusive results create a dilemma in patient management. A diuretic renogram protocol giving more conclusive results is the need of the hour.
At present, the widely practiced F+20 protocol has very high incidence of inconclusive results ranging from 10 to 40%.,,,, In view of this confusion, many studies have been done comparing F+20 protocol with F-15 and F+0 protocols.
Obstruction can be assessed by measuring the clearance curves, either from a visual assessment of the pattern or quantitate rate of washout by measuring the T1/2 (time for the activity in the collecting system to fall to 50% of its original value). Prompt clearance of the tracer from the renal pelvis with a T1/2 <10 min is a normal response and excludes obstruction. Values between 10 and 20 min are often considered to be equivocal, and a T1/2 >20 min is considered for obstruction.
Foda et al. reported a study in which 72 children were randomly assigned to 1 of 2 standardized diuresis renography protocols. The F-15 scan showed 7 times more obstruction than the F+20 scan on the investigated side, and this difference was statistically significant.
Similarly, in our study, 40% (24) RU were equivocal in F+20 protocol. The F-15 protocol conclusively categorized 23 RU as either obstructed or nonobstructed leaving only 1 RU as equivocal. Hence, in F-15 protocol, equivocal results were significantly lower than F+20 protocol.(p 0.001)
Four RU which were evaluated as an obstructive in the F+20 protocol showed a nonobstructive pattern in the F-15 protocol. Rest all of the RU showing obstructive or nonobstructive patterns in the F+20 study also revealed the same in the F-15 investigation.
Babu et al. studied 148 diuretic renograms in infants and children to evaluate unilateral Grade 3–4 HDN. The number of interrupted studies was significantly less in F+0 compared with F-15 and F+20. The F+0 and F-15 protocols are superior to the F+20 protocol in reducing the number of equivocal curves.
In our study, no interruption of the study reported possibly due to high bladder capacity in adults compared to children.
Türkölmez et al. published a study of 22 adult patients (28 kidneys) with upper urinary tract dilatation. None of the patients showed equivocal results in F-15 protocols. In the F+20 studies, 7 of the 28 kidneys were evaluated as equivocal, of these 5 kidneys showed nonobstructive and 2 kidneys revealed obstructive renogram patterns with the F-15 protocol.
Most of the earlier studies were done on pediatric patients. In our study, we included only adult patients because adult primary HDN is a common presentation in developing country like India and management of primary HDN in adults is significantly different from children.
In our study, all the patients underwent both the renography protocols which excluded the selection bias, a possibility in earlier studies where patients were divided into groups.
This is the first study in English literature (as per our knowledge) where we studied clinical presentation of patients with comparison of two diuresis protocols. Incidental diagnosis of HDN and HDN with vague symptoms is a common presentation in adults (40% in our study). Inconclusive results of diuresis renography in these patients create a dilemma for the treating clinician regarding the management. The important observation of our study is that the more than 60% (15/24) RU diagnosed incidentally and presented with vague symptoms resulted as inconclusive results in F+20 protocol. The F-15 protocol categorized all of the equivocal results as nonobstructive. This shows that results of F-15 protocol were mostly conclusive and could be correlated with patients presentation. This also suggests that HDN in these patients may not be due to obstruction but may be a normal variant of the pelvicalyceal system in adults, thereby helping in decision-making for the patients.
| Conclusion|| |
In our study, F-15 diuresis renogram protocol was associated with significantly less equivocal results than F+20 protocol. Moreover, F-15 protocol allowed clarification in cases of equivocal results of F+20 protocol. Therefore, we suggest the F-15 diuresis protocol as a single test for confirmation or exclusion of obstruction.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]