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E1117. Make Your Flow Glow! Renal Scintigraphy for the Radiology Resident
Authors
  1. Nandakumar Menon; West Los Angeles VA Medical Center
  2. Suzan Parhizgar; West Los Angeles VA Medical Center
  3. Sipan Mathevosian; UCLA Medical Center, David Geffen School of Medicine
  4. Matilda Jude; West Los Angeles VA Medical Center
  5. Chiayi Ni; Olive View UCLA Medical Center
  6. Diego Davila; Olive View UCLA Medical Center
  7. Karoly Viragh; Olive View UCLA Medical Center
Background
Renal scintigraphy is an important diagnostic tool in the imaging armamentarium in spite of recent underutilization in favor of CT/MR. Our goal is to provide an interactive review of renal scintigraphy with cross-sectional imaging and surgical-pathologic correlation through selected cases for general clinical practice and board examinations.

Educational Goals / Teaching Points
1. Overview of nuclear imaging of the genitourinary system to introduce available techniques and their utility/performance in comparison to cross-sectional imaging modalities (renal scintigraphy, SPECT, and PET compared to US/CT/MR). 2. Review renal scintigraphy indications and technique (radiopharmaceuticals, patient preparation, positioning, and image acquisition). 3. Teach algorithmic interpretation of renal scintigraphy with illustrative cases.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
The indications of renal scintigraphy will be presented. The most important application is functional evaluation of the urinary system, including renal perfusion, parenchymal uptake and transit, and excretion. Anatomic evaluation of the kidneys is a less frequent application. A clinically-relevant review of the general renal scintigraphy technique will be discussed. Imaging is performed on a gamma camera, most commonly with Tc-99m MAG3. Tc99-DTPA and Tc99-DMSA will be briefly discussed. An algorithmic approach to interpretation will be provided. Renal scintigrams are evaluated first qualitatively, then quantitatively. Qualitative evaluation of perfusion and parenchyma will be explained. Quantitative evaluation includes generation of a renogram, from which multiple parameters can be derived. Multiple cases will be presented for practice in a quiz-like format. (1) Diuretic renal scintigraphy will be reviewed. Multiple examples will be provided to illustrate the range of pathologies (obstructive hydronephrosis due to strictures, stones, masses, as well as functional hydronephrosis from dilation and atony in the setting of infection, reflux) with troubleshooting pearls and pitfalls (nephrostomy/stent, leakage, poor hydration, underlying parenchymal renal disease, very full bladder, incontinence). (2) Additional cases: ACE-inhibitor scintigraphy, parenchymal evaluation with split function, renal transplant evaluation for rejection and vascular patency, cortical imaging, pyelonephritis in children.

Conclusion
Renal scintigraphy remains an important diagnostic tool with its most significant application being functional evaluation of the urinary system.