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ISSN: Print -2349-0977, Online - 2349-4387


 
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ORIGINAL CONTRIBUTION - CLINICS IN NUCLEAR MEDICINE
Year : 2016  |  Volume : 3  |  Issue : 1  |  Page : 15-18

Role of renal cortical scintigraphy with Tc99m-DMSA in diagnosing renal scarring in patients undergoing staged reconstruction of classical urinary bladder exstrophy


1 Department of Nuclear Medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
2 Department of Paediatric Surgery, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India

Date of Web Publication20-Oct-2016

Correspondence Address:
Ravinder S Sethi
Department of Nuclear Medicine, V.M.M.C. and Safdarjung Hospital, New Delhi - 110 029
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2349-0977.192711

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  Abstract 

Objectives: The purpose of this study was to find out incidence of renal cortical scintigraphy done with Technetium-99m (Tc-99m) dimercaptosuccinic acid III (DMSA-III), scan to diagnose cortical scarring in patients undergoing staged reconstruction of exstrophy bladder. Patients and Methods: We retrospectively reviewed 29 post operative patients who were referred to our department for Tc99m-DMSA scan to look for renal cortical scarring from January 2012 to April 2016. Tc-99m DMSA(III) scan was done in all 29 patients (58 kidneys). Tc-99m DTPA and Tc-99m L, L-EC scans were done in 9 (18 kidneys) and 2 (4 kidneys) patients respectively. Results: Out of 29 patients male comprised 69% of cases (n = 20) and female comprised 31% of cases (n = 09).The mean age of the presentation of patients with exstrophy bladder was 7.8 years. Tc-99m DMSA(III) scan was done in 29 patients (58 kidneys).Scarring was noted in 28/58 kidneys (48.27%) on Tc-99m DMSA(III) scan. Tc-99m DTPA scan was done in 9 patients (18 kidneys). In Tc-99m DTPA scan mean GFR (standardized Gates gamma camera method) was 71.91ml/min. Micturating cystouretherography(MCU) was done in 10 patients which revealed vesicoureteric reflux(VUR) in all the patients. DRCG was done in 1 patient which showed unilateral high grade VUR. Ultrasonography (USG) was done in 29 patients. Eighteen patients were found to have normal USG findings. Four patients had bilateral hydroureteronephrosis (HDUN) and one had unilateral HDUN. Three had mild hydronephrosis (HDN) and 3 had gross HDN. Conclusion: Preservation of renal function is one of the major goals of staged reconstruction of bladder exstrophy. Renal cortical scintigraphy with Tc-99m DMSA-III has become the “the gold standard” for renal cortical scarring imaging. Hence Tc-99m DMSA scan offers a significant diagnostic advantage over other diagnostic modalities to diagnose and follow up renal cortical scarring in patients with exstrophy bladder thus help in management.

Keywords: Exstrophy bladder, renal cortical scintigraphy, renal scarring, Technetium-99m (Tc-99m) dimercaptosuccinic acid III (DMSA-III)


How to cite this article:
Namgyal PA, Sethi RS, Bagga D, Sehgal AK, Kumar D. Role of renal cortical scintigraphy with Tc99m-DMSA in diagnosing renal scarring in patients undergoing staged reconstruction of classical urinary bladder exstrophy. Astrocyte 2016;3:15-8

How to cite this URL:
Namgyal PA, Sethi RS, Bagga D, Sehgal AK, Kumar D. Role of renal cortical scintigraphy with Tc99m-DMSA in diagnosing renal scarring in patients undergoing staged reconstruction of classical urinary bladder exstrophy. Astrocyte [serial online] 2016 [cited 2021 Nov 30];3:15-8. Available from: http://www.astrocyte.in/text.asp?2016/3/1/15/192711


  Introduction Top


The most common congenital urinary bladder lesion is exstrophy. It is the result of a deficiency in the development of the lower abdominal wall musculature such that the bladder is open and the mucosa of the bladder is continuous with the skin. There is associated epispadias in which the urethra is open dorsally and the urethral mucosa covers the dorsum of a short penis. The incidence of this condition varies between 1:10000 and 1:50000 live births, and has a male/female ratio of 2:1. Skeletal and gastrointestinal anomalies are commonly associated with exstrophy. Separation of the symphysis pubis correlates directly with the severity of the exstrophy-epispadias complex. In full blown exstrophy, the pubic bones are widely separated. The exstrophy-epispadias complex may be associated with ureteric obstruction and unilateral or bilateral pelvicaliectasis due to fibrosis at the ureterovesical junction. However, in most cases, the upper urinary tracts are normal, however, there may be widening of the distal ureters. Radiologic assessment in such patients is required at periodic intervals to exclude the adenocarcinoma of the colon that may develop at the ureterosigmoid anastomosis.[1] The exposed bladder mucosa may undergo colonic glandular metaplasia and is subject to infections that often spread to the upper levels of the urinary system.[2] One of the methods of treatment of these patients is by the staged reconstruction of bladder exstrophy. Preservation of renal function is one of the major goals of staged reconstruction of bladder exstrophy.[3] Technitium99m(Tc-99m) DMSA-III has become the “the gold standard” for renal cortical scarring imaging because a significant fraction of the injected radiotracer localizes to the renal cortex via binding within the proximal tubules.[4]


  Patients and Methods Top


We retrospectively reviewed 29 patients [Table 1], undergoing staged reconstruction of classical bladder exstrophy from January 2012 to April 2016 who were referred to our department for Tc99m-DMSA scan to rule out renal cortical scarring. Some of these patients were also referred for Tc99m-DTPA (diethylene triamine pentaacetic acid) or Tc99m-L, L-EC (ethylene dicysteine) scans to look for renal function and drainage pattern.
Table 1: Table depicting the age, sex distribution and various investigations in patients undergoing staged repair of Urinary Bladder Exstrophy

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Tc-99m DMSA(III), Tc-99m DTPA, and Tc-99m L, L-EC were prepared from BRIT (Board of Radiation Isotope Technology) and BARC (Bhabha Atomic Research Centre, Mumbai) kits. All the children were injected with a weight-adjusted dose of the radiopharmaceutical based on the maximal dose of 3 mCi (111 MBq). The minimum administered dose was 1 mCi (37 Mbq).

DMSA scan was acquired 3 h after Tc-99m DMSA(III) injection in a supine position using a rotating large field-of-view, dual head gamma camera (Precedence 16 SPECT-CT, Philips) fitted with low energy, high resolution collimator, set at 140 keV with a 20% energy window. Planar images were acquired in four projections including anterior, posterior, right posterior oblique, and left posterior oblique views of kidneys, for 500,000 counts/image in 256 × 256 matrix. Differential function in Tc-99m DMSA scan was acquired using the geometric mean of both anterior and posterior images.

In Tc-99m DTPA and Tc-99m L, L-EC scans, flow/perfusion images of 2 s per frame for 60 s were acquired followed by dynamic/cortical phase of 30 s per frame for 25 min. Then, pre-void, post-void, and delayed images were acquired. Processing involved drawing the region of interest around the kidneys and background, generating time activity curves for flow and dynamic phases. Differential function and glomerular filtration rate (GFR) for individual kidneys were determined.


  Results Top


Age of presentation of the 29 patients with exstrophy bladder ranged between 5 months and 15 years, with a mean age of 7.8 years. Out of the 29 patients, males comprised 69% of the cases (n = 20) and female comprised 31% of the cases (n = 9). Range of age at presentation in males was 5 months to 15 years and in females 3–12 years of age. The patients were undergoing staged reconstruction, as being practised in this hospital, as follows:

Stage I: Primary bladder turn in

Stage II: Epispadias repair

Stage III: Bladder neck repair

Stage IV: Bladder augmentation.

Kidney function tests (KFT), blood urea, and serum creatinine (Sr. Creat.) done in these patients were within normal limits in 26 out of 29 patients. Three patients had raised Sr. Creat. (1.2–1.8 mg/dl; mean: 1.56 mg/dl).

Out of the 29 patients, 6 patients with mean age of 3.9 years were referred for Tc-99m DMSA scan after Stage I repair; 2 of these 6 patients, i.e., 4/12 kidneys (33.3%) showed scarring on Tc-99m DMSA scan. Out of the 29 patients, 9 patients with a mean age of 8.2 years were referred for Tc-99m DMSA scan after Stage II repair; scarring was noted in 6 of the 9 patients, i.e., 10/18 kidneys (55.5%). Out of the 29 patients, 8 patients with a mean age of 7.9 years were referred after Stage III repair; scarring was noted in 5 of these 8 patients, i.e., 7/16 kidneys (43.75%). Out of the 29 patients, 6 patients with mean age of 11.6 years were referred after Stage IV repair; scarring was noted in 4 out of these 6 patients, i.e., 7/12 kidneys (58.3%). In all, Tc-99m DMSA (III) scan was done in 29 patients (58 kidneys). Renal scarring was noted in 16 patients, i.e., 28/58 kidneys (48.27%).

Tc-99m DTPA scans were done in 9 patients (18 kidneys) to look for GFR and drainage pattern. Standardized gates gamma camera method GFR ranged from 48.71–105.1 ml/min and the mean GFR was 71.91 ml/min. Out of the 18 kidneys, 13 showed good cortical function with good subrenal drainage. Five kidneys showed impaired cortical function. One patient showed bilateral and 1 patient showed unilateral hydroureteronephrosis (HDUN). All these 3 kidneys with HDUN showed scarring. Two kidneys out of 18 were small with impaired function, with both showing scarring on the Tc-99m DMSA scan. One kidney out of 18 was ectopic in position and revealed a scar on the Tc-99m DMSA scan.

Tc-99m L, L-EC scan was done in 2 patients to ascertain function and drainage pattern. Results showed good cortical function and good subrenal drainage in 1 patient; Tc-99m DMSA scan of this patient was normal. Bilateral HDUN with impaired function and slow drainage was noted in another patient whose Tc-99m DMSA scan revealed scarring in both the kidneys. Direct radionuclide cystography (DRCG) was done in 1 patient. High grade vesicoureteric reflux (VUR) was noted in the left kidney. Subsequently Tc-99m DMSA scan done in this patient revealed scar at the upper pole of left kidney. Corresponding micturating cystouretherography (MCU) of this patient showed bilateral VUR, with grade 2 on the right side and grade 3 on the left side. Ultrasonography (USG) in this patient revealed normal kidneys.

USG was done in all 29 patients. Eighteen patients (36 kidneys) were found to have normal kidneys on USG. However, on corresponding Tc-99m DMSA (III) scans, 13/36 kidneys (36%) showed scarring. Four patients (8 kidneys) had bilateral HDUN. Out of these 4 patients, scarring was noted on USG in 2 patients (4/8 kidneys) whereas Tc99m DMSA (III) scan in these patients showed scarring in 6/8 kidneys (75%). One patient had unilateral HDUN and showed scarring in Tc-99m DMSA(III) scan in the kidney while no scar was noted on USG. Three patients (6 kidneys) had mild hydronephrosis (HDN) which on Tc-99m DMSA(III) scan revealed scarring in 5/6 kidneys (83.3%) while USG showed scarring in 2/6 kidneys. Three patients (6 kidneys) showed gross HDN in both the kidneys and showed scarring in 4/6 kidneys (66.6%) on Tc-99m DMSA scan while no scar was noted in USG. Therefore, on USG 10.3% (03/29 patients or 6/58 kidneys) showed scarring whereas scarring was noted in 48.27% (16/29 patients or 28/58 kidneys) on Tc-99m DMSA (III) scan. USG showed 1 patient with an absent kidney, while on DMSA scan this was found to be ectopically located with adequate function and cortical scar.

MCU was done in 10 patients. All of them revealed small capacity urinary bladder (approximate volume of 50 cc) with VUR. Tc-99m DMSA (III) scan of these patients revealed scarring in 05/10 patients.


  Discussion Top


In our study, there were 69% males and 31% females who were referred to our department at various stages of operation to look for cortical scarring. The exstrophy-epispadias complex may be associated with ureteric obstruction and unilateral or bilateral pelvicaliectasis due to fibrosis at the ureterovesical junction.[1] Few studies are available regarding the role of renal scintigraphy in the follow up of staged reconstruction of exstrophy bladder. In known literature, there is less involvement of kidneys/upper urinary tract at birth in patients with exstrophy bladder.[1] There is increased incidence of VUR and pyelonephritis.

In our study of 29 patients (58 kidneys) who underwent Tc-99m DMSA (III) scan, cortical scarring was noted in 48.27% kidneys (28/58 kidneys). Maximum scarring was noted in patients after stage IV repair, i.e., 58.3%, and minimum scarring was seen in patients after stage I repair, i.e., 33.3%. Cortical scarring in stages II and III was 55.5 and 43.75%, respectively. Incidence of renal scarring/pyelonephritis in this study was high. Furthermore, it was noted that renal scarring increased in patients who had undergone stage-II reconstruction compared to patients who had undergone stage-III reconstruction. This discrepancy and the high incidence of renal cortical scarring may be due to small sample size, patients not having access to antibiotics, as per requirement, and bias in the referral of symptomatic patients. Mouriquand et al. observed that 65% presented with recurrent urinary tract infections after bladder neck reconstruction after a Young-Dees-Leadbetter procedure.[5]

In our study, VUR was noted in all 10 patients who had undergone MCU. Tc-99m DMSA (III) scan of these patients revealed scarring in 5/10 patients (50%). Computed tomography (CT) scan can often identify the inflammatory change in the kidney, as can radiolabelled white blood cells and gallium-67 citrate. However, these tests are not for frequent use, especially in children.[6]

In this study, on USG, 10.3% (3/29 patients or 6/58 kidneys) showed scarring, whereas on Tc-99m DMSA (III) scan scarring was noted in 48.27% kidneys (16/29 patients or 28/58 kidneys). Therefore, in this study USG proved to be less sensitive than Tc99m DMSA scan in diagnosing renal cortical scarring. USG is frequently performed as a first line imaging tool for suspected pyelonephritis, although there is lower sensitivity for early infection. Renal cortical scintigraphy with Tc-99m DMSA-III is significantly more sensitive than sonography.[6] This study also showed similar results. In addition, DMSA scan localized an ectopic kidney reported as absent on USG.

In these 29 patients, there was 1 ectopic kidney, however, there were no absent, horse shoe, or duplex kidneys were noted, which coincides with the known literature.[1]


  Conclusion Top


Patients with exstrophy bladder have high incidence of VUR and are predisposed to pyelonephritis. Preservation of renal function is one of the major goals of staged reconstruction of bladder exstrophy.[3] This study shows that the incidence of pyelonephritis may increase with the stage of reconstruction or time. Hence, Tc-99m DMSA-III scan offers a significant diagnostic advantage over other diagnostic modalities in exstrophy bladder patients in diagnosis and postoperative management. Therefore, it is recommended that a further study with more number of patients may be undertaken to determine the incidence of renal scarring in patients with exstrophy bladder undergoing staged repair.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Congenital Anomalies. In: Dunnick NR, Sandler CM, Newhouse JH, Amis ES, editors. Text book of Uroradiology. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2001. p. 36.  Back to cited text no. 1
    
2.
Kumar V, Abbas AK, Aster JC, Pathologic Basis of Disease, South Asia Edition, 2015, pg 962 Elsevier.  Back to cited text no. 2
    
3.
Husmann DA, Mclorie GA, Churchill BM. Factors predisposing to renal scarring: Following staged reconstruction of classical bladder exstrophy. J Pediatr Surg 1990 may; 25:500-4.  Back to cited text no. 3
    
4.
MacKenzie JR. DMSA-The new “gold standard”. Nucl Med Commun 1990;11:725-6.  Back to cited text no. 4
    
5.
Genitourinary System. In: Zeissman HA, O'Malley JP, Thrall JH, Fahey FH, editors. Nuclear Medicine: The Requisites. 4th ed. Philadelphia: W.B. Saunders; 2010. p.168-203.  Back to cited text no. 5
    
6.
Mouriqunad PD, Bubanj T, Feyaerts A, Jandric M. Long Term results of baladder neck reconstruction ofr inconteinence in children with classical bladder exstrophy or incontinent epispadias. BJU Int 2003;92:997-1001.  Back to cited text no. 6
    



 
 
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