Case Author(s): Jayson R. St. Jacques, M.D. and Barry A. Siegel, M.D. , . Rating: #D3, #Q3
Diagnosis: Renal transplant infarction, acute tubular necrosis, and acute hematoma
Brief history:
37-year-old woman with recent renal transplant
Images:
Renal scintigraphy images, including radionuclide angiogram, sequential images, and delayed spot images.
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View second image(rs).
Renal scintigraphy images obtained 2 days later, including radionuclide angiogram, sequential images, and 4-hour delayed image.
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Renal sonograms
Full history/Diagnosis is available below
Diagnosis: Renal transplant infarction, acute tubular necrosis, and acute hematoma
Full history:
37-year-old woman with end-stage renal disease due to hypertensive nephropathy. Six months ago, she received a living-related-donor kidney transplant, which failed secondary to renal vein thrombosis and was removed. She now has a new transplanted cadaveric kidney in the left iliac fossa. The transplanted kidney had two renal arteries, and a lower pole artery reconstruction was necessary as part of the transplant procedure. The patient has poor urine output, and renal scintigraphy was thus requested to evaluate renal function.
Radiopharmaceutical:
7.4 mCi Tc-99m MAG3 i.v. for first study
7.9 mCi Tc-99m MAG3 i.v. for second study
Findings:
Initial transplant renal scintigraphy study:
The radionuclide angiogram images demonstrate hypoperfusion of the upper pole of the transplanted kidney. Sequential images show slowly increasing activity in the renal cortex as well as a wedge-shaped defect in the lower pole of the kidney. There is overall poor function and poor excretion of the tracer. The findings were considered consistent with moderately severe acute tubular necrosis with a focal infarct in the lateral aspect of the lower pole of the kidney.
Second transplant renal scintigraphy performed two days later:
Given the findings of the initial study and the patient's history of renal vein thombosis causing one failed tranplant in the past, the patient was put on intravenous heparin therapy to prevent further infarcts or renal vein thombosis. The patient had an additional drop in her urine output, and repeat imaging was performed to evaluate the renal transplant. This repeat study demonstrated a new large photopenic region medial to the transplant suggestive of an acute hematoma, urine leak, or other fluid collection. 4-hour delayed images demonstrate no significant accummulation of tracer in this region to suggest a urine leak, and an acute hematoma was thus considered most likely. Again noted are wedge-shaped defects in the renal transplant most consistent with infarcts and significant activity remaining within the renal cortex at 4 hours compatible with acute tubular necrosis. The Foley catheter drainage bag was placed along side the patient.
Ultrasonography of the renal transplant demonstates a large, heterogeneous complex mass-like collection adjacent to the renal transplant suggestive of an acute hematoma.
Discussion:
Renal transplant scintigraphy imaging is a useful tool to evaluate the dynamic processes of the urinary system. Early dynamic imaging (radionuclide angiography) at the time of injection of the radiopharmaceutical demonstates blood flow to the transplant relative to iliac vessel flow. Sequential images demonstate cortical function and morphology, and then show excretion into the reanl calyces, pelvis, ureter and bladder. Evaluation for obstuction or urine leak can be performed non-invasively at this stage. Usually acute hematoma or urine leak is seen soon after transplantation, in contrast to lymphocele formation usually seen weeks to months after transplantation.
ACR Codes and Keywords:
References and General Discussion of Renal Scintigraphy (Anatomic field:Genitourinary System, Category:Misc)
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Case number: rs030
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