|Year : 2019 | Volume
| Issue : 1 | Page : 57-59
Gall bladder activity on technetium99m-ethylenedicysteine renogram masquerading as ectopic kidney
Sailaja Aka, J Sai Moulika, VS Krishna Mohan, R Ramya Priya, Ranadheer Manthri, TC Kalawat
Department of Nuclear Medicine and PET CT, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
|Date of Web Publication||17-Jan-2019|
Dr. Ranadheer Manthri
Department of Nuclear Medicine, Sri Venkateswara Institute of Medical Sciences, Tirupati - 517 501, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
99mTc-EC (Technetium-99m-ethylenedicysteine) is a renal tubular imaging agent introduced as an alternative to 99mTc-MAG3 (Technetium-99m-mercaptoacetyltriglycine) (1). This radiopharmaceutical can be easily labeled at room temperature and has high radiochemical purity and long stability for at least 8 h. Within 1 h 70% of 99mTc-EC is excreted in the urine (2). 99mTc-EC provides the same Scintigraphic information as 99mTc-MAG3. The Hepato biliary excretion of 99mTc-EC is very low and usually does not affect image interpretation on routine imaging, the possibility of visualization of the gall bladder should be kept in mind while reporting the 99mTc-EC renogram (1). We present a case of 99mTc-EC renogram, a suspected case of hypoplastic/ectopic right kidney, to look for ectopic kidney. In this case, there was unexpected visualization of gallbladder in delayed images. We herewith present this case, so that physician should be careful while reporting 99mTc-EC renogram, as there may be chances for gall bladder to be masquerading as Ectopic kidney.
Keywords: Diuretic renogram, ectopic kidney, gallbladder, technetium-99 m-ethylenedicysteine
|How to cite this article:|
Aka S, Moulika J S, Krishna Mohan V S, Priya R R, Manthri R, Kalawat T C. Gall bladder activity on technetium99m-ethylenedicysteine renogram masquerading as ectopic kidney. Indian J Nucl Med 2019;34:57-9
|How to cite this URL:|
Aka S, Moulika J S, Krishna Mohan V S, Priya R R, Manthri R, Kalawat T C. Gall bladder activity on technetium99m-ethylenedicysteine renogram masquerading as ectopic kidney. Indian J Nucl Med [serial online] 2019 [cited 2020 Feb 24];34:57-9. Available from: http://www.ijnm.in/text.asp?2019/34/1/57/250345
| Introduction|| |
Technetium99m-ethylenedicysteine (99m Tc-EC) was first introduced as a potential renal tubular imaging agent alternative to technetium-99 m mercapto-acetyl-triglycine (99m Tc-MAG3). The hepatobiliary excretion of 99m Tc-EC is very low and usually does not affect image interpretation on routine imaging. However, the possibility of visualization of the gallbladder, which might mimic an ectopic kidney, should be kept in mind while reporting the 99m Tc-EC renogram study. Here, we present an interesting case of a 4-year-old child suspected for ectopic right kidney in whom 99m Tc-EC renogram study was performed, and the scan revealed abnormal visualization of gallbladder simulating as an ectopic kidney.
A 4-year-old male child presented with left loin pain and fever. On ultrasound abdomen, the right kidney was not visualized, and right ureterocele was present. The patient was referred for 99m Tc-EC renogram for localization of ectopic kidney, function, and subsequent drainage of kidneys. After intravenous administration of 1.4 mCi 99m Tc-EC with 10 mg furosemide, the patient was placed in supine position, and dynamic images were acquired using Symbia E dual head Gamma camera (Siemens).
Renogram study showed that the left kidney was normal in size and shape and located slightly inferior to normal position. Perfusion and initial dynamic images showed mildly reduced radiotracer uptake in renal parenchyma, with normal intrarenal transit time. Drainage into collecting system and subsequent clearance were appropriate, with increase in counts during delayed images and showing double peak which was suspicious for vesicoureteric reflux. The right kidney was not visualized in the right renal fossa [Figure 1].
|Figure 1: Posterior dynamic images of Technetium-99m-ethylenedicysteine renogram for a 4-year-old boy, suspected for hypoplastic/ectopic right kidney|
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Delayed static images were acquired for 60 s on 128 × 128 matrix at 2 and 4 h postinjection [Figure 2]. There was focally increased tracer concentration in the right hypochondrium in delayed 2 h image and another focus of increased radiotracer concentration just below it. In view of suspected ectopic kidney, abnormal radiotracer localization in the right hypochondrium was initially thought as ectopic kidney and to confirm it a single-photon emission computed tomography (SPECT) CT scan was done. The abnormal foci of increased radiotracer uptake in the right hypochondrium corresponded to gallbladder and bowel on axial fused SPECT CT images [Figure 3]. With the aid of SPECT CT images, we were able to confirm the two abnormal foci of radiotracer concentration as gallbladder and bowel rather than ectopic kidney.
|Figure 2: (a and b) Immediate images after dynamic study (prevoid) both anterior and posterior. (c and d) 2-h delayed images. (e and f) 4-h delayed images. Delayed images showing hepatobiliary excretion (visualization of gallbladder and bowel)|
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|Figure 3: Fused SPECT/CT axial (a) and coronal (b) images shows abnormal radio tracer uptake in right hypochondrium corresponds to uptake in gall bladder on CT|
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| Discussion|| |
99m Tc-EC has efficient extraction fraction and excretion through the kidneys and is closer to 99m Tc-MAG3 in function., It provides high-quality images due to negligible liver accumulation and high kidney to background ratio., Different authors had shown significantly low accumulation of 99m Tc-EC in the liver and intestine than that of 99m Tc-MAG3 in animals as well as in humans. The lower liver activity makes 99m Tc-EC particularly attractive in patients with renal failure. The presence of different stereoisomers of 99m Tc-EC in different kits may result in different excretion characteristics of EC.
However, the visualization of gallbladder with non-hepatobiliary radiopharmaceuticals was also reported in many studies, and it was not always pathological. Previous authors had documented hepatobiliary excretion of 99m Tc-EC as a region of normal biodistribution of the tracer., Another cause for altered biodistribution of a radiopharmaceutical was thought to be as a result of its low radiochemical purity., Gallbladder visualization in the present study cannot be attributed to the quality of 99m Tc-EC because gallbladder activity was not seen in any other patient injected with the same preparation of 99m Tc-EC on the same day.
Arora et al. reported a case of dual cadaveric renal transplant, who underwent an EC renogram and showed incidental uptake in gallbladder on delayed images, confirmed on SPECT/CT images.
Jain et al. reported a case with liver uptake on EC renogram. The initial perfusion images showed liver activity in the right abdominal region, which was thought to be due to high blood flow to the liver, but persistence of activity in the delayed image raised the suspicion for normally located impaired functioning enlarged right kidney. SPECT CT images acquired had confirmed the radiotracer localization in liver.
| Conclusion|| |
The possibility of visualization of the gallbladder should be kept in mind while reporting the 99m Tc-EC renogram. It might masquerade an ectopic kidney; hence, such cases need to be interpreted with caution.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]