Correlation of CTU with renal scintigraphy in assessing split Renal function .pptx

Correlation of CTU with renal scintigraphy in assessing split Renal function in resource limited set up

1. Correlation of CTU with renal scintigraphy in assessing split Renal function Abiy T.PGY-IV AAU,department of surgery,Urology division.

2. Functional imaging of kidney Split Renal function Differential renal function, is a determination of the relative contribution of each of the two kidneys to total renal function. Nuclear renal scan is currently the gold standard imaging study to determine differential renal function

3. IVU Once it was main stay of imaging Bowel prep clear liquids for 12 to 24 hours and an enema 2 hours before the procedure a scout radiograph or KUB allows determination of adequate bowel prep, confirms correct positioning, and exposes kidney stones or bladder stones. Nephrogenic phase-immediately after injecting contrast Film every 5min interval Positioning 24 hour film Post Void film

4. Indications Demonstration of the renal collecting systems and ureters Investigation of the level of ureteral obstruction Intraoperative opacification of collecting system during extracorporeal shock wave lithotripsy or percutaneous access to the collecting system Demonstration of renal and ureteral anatomy in special circumstances (e.g., ptosis, after transureteroureterostomy, and after urinary diversion)

5. CTU To evaluate the kidney, upper tract collecting system, and ureter. Definition diagnostic examination optimized for imaging the kidneys, ureters and bladder. Phases Precontract Arterial phase(20-30sec) Corticomedullary(30-70sec) Nephrogenic phase(80-120sec) Excretory phase(¬3’) Early Delay Radiation dose

6. Indications for CTU Workup of Hematuria , Kidney stones, Renal masses, Renal colic, Urothelial tumors . Ureteral injury Recurrent UTI Variant anatomy

7. Techniques No special preparation No oral contrast agent Hydration Positioning Contrast Media injection-Iodine commonly used Single bolus injection Split bolus injection “triple bolus single CTU” Low dose Lasix assisted version

8. MRU Static-fluid T2-weighted sequences and excretory T1-weighted sequences (excretory MRU)with IV contrast Can be used to evaluate the Renal parenchyma, T he pelvicaliceal system, and The rest of the urinary tract in a single imaging study as in CT urography Adv -without radiation exposure and IV contrast administration. pediatric and pregnant patients and patients with renal impairment Disadv - MRU is limited by longer examination times than for CT urography, Decreased spatial resolution, and Inability to reliably depict calcifications and calculi.

9. Renal scintigraphy Radiotracers are designed to accumulate in tissues or organs on the basis of underlying functions unique to that organ . blood flow , renal uptake, and excretion Indications for imaging Evaluation of Functional obstruction Asses GFR Evaluation of Renal Vascular Hypertension Infection imaging Evaluation of renal transplant donor/receivers VUR Adv scintigraphy does not damage the kidney, has no lingering toxicity, results in minimal absorbed radiation, free from allergic reactions It is very sensitive to changes that induce focal or global changes in kidney function Types

10. 99mTc-DTPA Freely filtered by glomerulus and excreted without absorption Assess RPF to the kidneys functional renal obstruction Renal vascular HTN-captopril scintigraphy-decreased use over time

11. 99mTc-MAG3 Clearance-Secreted for tubules Low radiation High extraction efficiency -Good image quality Low cost, Ease of preparation 10% extra renal excretion and protein bound Less ability to measure GFR Dynamic study of kidney Perfusion to kidney and drainage assessment Study of choice in pts with renal insufficiency and urinary obstruction.

12. 99mTcDMSA Primarily cleared by GF Endocytosis by proximal tubular cells Identifying cortical defects or ectopic kidneys . Static study of kidney Pyelonephritis Renal scaring

13. Patient preparation Well hydration Medications Diuretics Patient positioning Any anatomic abnormalities Patients with ,BOO, nephrostomy tube

14. Image Acquisition and Interpretation Dynamic renal imaging is performed in two phases Perfusion phase, RPF to each individual renal unit is measured and compared with aorta Data are plotted on a time activity curve (TAC), A curve with a slow rise to peak suggests poor flow Brisk Upstroke Functional phase Measuring the area under the TACs-transit of radiotracer through kidney parenchyma and into the collecting system, with drainage to the bladder Normal split renal function. The curves for each kidney are roughly parallel in both shape and a split function difference of up to 10% is considered to be within normal limit Flow phase , Renal phase, Excretory phase

15. Diuretic Renography Diuretic Delayed clearance Protocol Initial phase The flow phase

16. Can we assess split renal function from CTU?

17. Calculating split renal function Frennby et al. in 1995, which we modified only to account for volume instead of cross-sectional area. 173 renal donor pt who have CTU and renal scan b/n march 2005 and feb 2006 @ University of Alabama at Birmingham ,US. Creating the 3D Kidney Model A workstation (Advantage Workstation, version 4.1, GE Healthcare) was used by one author to generate 3D Results-SRF assessment from 3D CT models showed correlation with no significant difference from renal scan’ Conclusion- CTU can give as one stop evaluation for both anatomic and functional characteristics of kidney

18. MATERIALS AND METHODS Between February 2011 and August 2011, 21 patients with unilateral obstructive uropathy were enrolled in this prospective comparative study. Exclusion criteria s.creatinine > 2 mg/dl and acute obstruction 21 pts with unilateral OUP subjected to both 99mTC - DTPA renal scan 64 slice helical CT scan ( CTU) CTU The volume estimation done with software GE medical system,light speed VCT Ct99) workstation (ADW 4.3). Individual renal split function by %=individual renal volume/Total renal volume Conclusions-Measurement of differential renal function by CT-based parenchymal volume correlates strongly with differential renal function estimated by 99mTC - DTPA renal scan in both obstructed and nonobstructed renal units

19. Advantages over Renal scan Reduces the cost of the evaluation. Conducting only one study also speeds up the evaluation process and reduces radiation exposure. Even more accurate than radionuclide renography– Measured split function because the latter varies significantly with patient habitus, kidney position, and the operator

20. How/where can we get ‘volume calculating’ software?

21. References Campbell and Wallace 12th edition, 2012 Determination of Split Renal Function by 3D Reconstruction of CT Angiograms: A Comparison with Gamma Camera Renography Authors :  Adam L. Summerlin ,  Mark E. Lockhart ,  Andrew M. Strang ,  Peter N.  Kolettis ,  Naomi S.  Fineberg , and  J. Kevin  Smith ,Nov 2008 Correlation between differential renal function estimation using CT-based functional renal parenchymal volume and 99mTc - DTPA renal scan Debanga Sarma , Sasanka K. Barua , Rajeev T. P., Saumar J. Baruah, Department of Urology, Gauhati Medical College and Hospital, Bhangagharh , Assam, India(pub Med) MRU,American Journal of Roentgenology September 195(3):W201

22. Thank You!