Renal Scintigraphy :Renal Scintigraphy


Indications :Indications Renal perfusion and function Obstruction (Lasix renal scan) Renovascular HTN (Captopril renal scan) Infection (renal morphology scan) Pre-surgical quantitation (nephrectomy) Renal transplant Congenital anomalies, masses (renal morphology scan) Evaluation of:


Renal Function :Renal Function Blood flow - 20% cardiac output to kidneys (1200 ml/min blood, 600 ml/min plasma) Filtration - 20% renal plasma flow filtered by glomeruli (120 ml/min, 170 L/d) Tubular secretion Tubular reabsorption (1% ultrafiltrate - urine) Endocrine functions


Renal RadiotracersExcretion Mechanisms :Renal RadiotracersExcretion Mechanisms GF TS TFTc-99m DTPA >95% Tc-99m MAG3 <5% 95% I-131 OIH 20% 80% Tc-99m GHA 40%-60% 20% Tc-99m DMSA some 60% Semin NM Apr.92


Renal Radiopharmaceuticals :Renal Radiopharmaceuticals Extract. fraction Clearance Tc-99m DTPA 20% 100-120 ml/min Tc-99m MAG3 40-50% ~ 300 ml/min I-131 OIH ~100% 500-600 ml/min


Renal RadiopharmaceuticalsDosimetry :Renal RadiopharmaceuticalsDosimetry DTPA MAG3 GHA DMSA I-131OIH rad/10 mCi rad/5mCi rad/300µCi Kidney 0.2 0.15 1.6 3.5 0.01 Bladder 2.8 5.1 2.7 0.3 0.3 EDE (rem) 0.3 0.4 0.4 0.3 0.03


Choosing Renal Radiotracers :Choosing Renal Radiotracers Perfusion MAG3, DTPA, GHA Morphology DMSA, GHA Obstruction MAG3, DTPA, OIH Relative function All GFR quantitation I-125 iothalamate, Cr-51 EDTA, DTPA ERPF quantitation MAG3, OIH Clin. Question Agent


Basic Renal ScanProcedure :Basic Renal ScanProcedure


Basic Renal ScintigraphyPatient Preparation :Basic Renal ScintigraphyPatient Preparation Patient must be well hydrated Give 5-10 ml/kg water (2-4 cups) 30-60 min. pre-injection Can measure U - specific gravity (<1.015) Void before injection Void @ end of study Int’l Consens. Comm. Semin NM ‘99:146-159


Basic Renal Scintigraphy Acquisition :Basic Renal Scintigraphy Acquisition Supine position preferred Do not inject by straight stick Flow (angiogram) : 2-3 sec / fr x 1 min Dynamic: 15-30 sec / frame x 20-30 min (display @ 1-3 min/frame)


Basic Renal Scintigraphy Acquisition (cont’d) :Basic Renal Scintigraphy Acquisition (cont’d) Obtain a 30-60 sec. image over injection site @ end of study if infiltration >0.5% dose do not report clearance Obtain post-void supine image of kidneys @ end of study Taylor, SeminNM 4/99:102-127


International Consensus Committee Recommendations for Basic Renogram :International Consensus Committee Recommendations for Basic Renogram Tracer: MAG3, (DTPA) Dose: 2 - 5 mCi adult, minimum 0.5 mCi peds Pt. position: supine (motion, depth issues) Include bladder, heart Collimator: LEAP Image over injection site Int’l Consens. Comm. Semin NM ‘99:146-159


DTPA normal :DTPA normal


DTPA normal :DTPA normal


Relative (split) functionROI’s :Relative (split) functionROI’s


Relative uptake :Relative uptake Contribution of each kidney to the total fct net cts in Lt ROI % Lt kid = --------------------------------------- x 100% net cts Lt + net cts Rt ROI Normal 50/50 - 56/44 Borderline 57/43 - 59/41 Abnormal > 60/40 Taylor, SeminNM Apr 99


Basic Renal Scintigraphy Processing :Basic Renal Scintigraphy Processing Time to peak Best from cortical ROI Normal < 5 min Residual Cortical Activity (RCA20 or 30) Ratio of cts @ 20 or 30 min / peak cts Use cortical ROI Normal RCA20 for MAG3 < 0.3 Residual Urine Volume (post-void cts x void. vol)  (pre-void cts - post void cts)


Slide 18:DTPA flow + scan GFR = 29 ml/’ Creat = 2.0 L= 33% R= 67%


Renal artery occlusion :Renal artery occlusion


Rt renal infarct :Rt renal infarct


Renogram Phases :Renogram Phases I. Vascular phase (flow study): Ao-to-Kid ~ 3” II. Parenchymal phase (kidney-to-bkg): Tpeak < 5’ III. Washout (excretory) phase


Renogram curves :Renogram curves


Evaluation of Hydronephrosis :Evaluation of Hydronephrosis Diuretic (Lasix) Renal Scan


Obstruction :Obstruction Obstruction to urine outflow leads to obstructive uropathy (hydronephrosis, hydroureter) and may lead to obstructive nephropathy (loss of renal function)


Diuretic Renal ScanPrinciple :Diuretic Renal ScanPrinciple Hydronephrosis - tracer pooling in dilated renal pelvis Lasix induces increased urine flow If obstructed >>> will not wash out If dilated, non-obstructed >>> will wash out Can quantitate rate of washout (T1/2)


Diuretic Renal Scan Indications :Diuretic Renal Scan Indications Evaluate functional significance of hydronephrosis Determine need for surgery obstructive hydronephrosis - surgical Rx non-obstructive hydronephrosis - medical Rx Monitor effect of therapy


Diuretic Renal Scan Requirements :Diuretic Renal Scan Requirements Rapidly cleared tracer Well hydrated patient Good renal function


Diuretic Renal Scan Procedure :Diuretic Renal Scan Procedure Pt. preparation: prehydration adults - oral or 360ml/m2 iv over 30’ peds - 10-15 ml/kg D5 0.3-0.45%NS void before injection bladder catheterization ?


Diuretic Renal Scan Procedure (cont’d) :Diuretic Renal Scan Procedure (cont’d) Tracers: Tc-99m MAG3 5-10 mCi (preferred over DTPA) Acquisition: supine until pelvis full (can switch to sitting post- Lasix) Flow (angiogram) : 2-3 sec / fr x 1 min Dynamic: 15-30 sec / frame x 20-30 min


Diuretic Renal Scan Procedure (cont’d) :Diuretic Renal Scan Procedure (cont’d) Void before Lasix Lasix: 40mg adult, 1mg/kg child iv @ ~10-20 min (when pelvis full) or @ -15min (“F-15” method) Acquisition for 30 min post Lasix Assess adequacy of diuresis Measure voided volume Adults produce ~200-300 ml urine post-Lasix


Diuretic Renal Scan Procedure (cont’d) :Diuretic Renal Scan Procedure (cont’d) Don’t give Lasix if Collecting system still filling Collecting system not full by 60 min Collecting system drains spontaneously Poor ipsilateral fct (< 20%)


pre-Lasix :pre-Lasix


post-Lasix :post-Lasix


No UPJ obstruction :No UPJ obstruction T1/2 R = 6’ L = 2’


Post-Lasix curve :Post-Lasix curve


Pre-Lasix :Pre-Lasix 10 y/o M


Post-Lasix :Post-Lasix


Rt UPJ obstruction :Rt UPJ obstruction T1/2 R = N/A F/U - nephrostomy tube placed


Slide 39:3164897 3-wk old baby Lt hydronephrosis


Slide 40:3164897 Lt UPJ obstruction


Rt UPJ obstruction :Rt UPJ obstruction T1/2 R = N/A F/U - nephrostomy tube placed


Slide 42:3164897 Lt UPJ obstruction


Diuretic Renal Scan Processing :Diuretic Renal Scan Processing ROI placement around whole kidney or around dilated renal collecting system T/A curve T1/2 from Lasix injection vs. from diuretic response linear vs. exponential fit of washout curve


Diuretic Renal Scan Washout(diuretic response) :Diuretic Renal Scan Washout(diuretic response) T1/2 time required for 50% tracer to leave the dilated unit i.e. time required for activity to fall to 50% of peak


T1/2 washout :T1/2 washout cts 100% 50% T1/2 min


T1/2 value :T1/2 value Variables influencing T1/2 value: Tracer State of hydration Volume of dilated pelvis Bladder catheterization Dose of Lasix Renal function (response to Lasix) ROI (kidney vs. pelvis) T1/2 calculation (from inj. vs. response, curve fit)


T1/2 :T1/2 Normal 20 min Indeterminate 10 - 20 min Best to obtain own normals for each institution, depending on protocol used


Diuretic Renal Scan Interpretation :Diuretic Renal Scan Interpretation Interpret whole study, not T1/2 alone Visual (dynamic images) Washout curve shape (concave vs. convex) T1/2


Diuretic Renal Scan Pitfalls :Diuretic Renal Scan Pitfalls False positive for obstruction Distended bladder Gross hydronephrosis T(transit time) = V (volume)  F (flow) Poorly functioning / immature kidney Dehydration False negative Low grade obstruction Poorly functioning / immature kidney


Effect of catheterization (1) :Effect of catheterization (1) full bladder,no catheter


Effect of catheterization (2) :with catheter in bladder Effect of catheterization (2)


Effect of catheterization (3) :Effect of catheterization (3) with catheter without catheter


“F minus 15” Diuretic Renogram :“F minus 15” Diuretic Renogram Furosemide (Lasix) injected 15 min before radiopharmaceutical Rationale: kidney in maximal diuresis,under maximal stress Some equivocals will become clearly positive, some clearly negative English, Br JUrol 1987:10-14Upsdell, Br JUrol 1992:126-132


Evaluation of Renovascular Hypertension :Captopril Renal Scan (ACEI Renography) Evaluation of Renovascular Hypertension


Renovascular Disease :Renovascular Disease Renal artery stenosis (RAS) Ischemic nephropathy Renovascular hypertension (RVH) RAS  RVH


Renovascular Hypertension :Renovascular Hypertension Caused by renal hypoperfusion Atherosclerosis Fibromuscular dysplasia Mediated by renin - AT - aldosterone system Potentially curable by renal revascularization


Renovascular Hypertension :Renovascular Hypertension Prevalence 50y Severe HTN resistant to medical Rx Unexplained or post-ACEI impairment in ren fct HTN + abdominal bruits If these present - moderate risk of RVH (20-30%)


Renin-Angiotensin System :Renin-Angiotensin System RAS Captopril Angiotensinogen Angiotensin I Angiotensin II Aldosterone Vasoconstriction HTN Renin ACE


Effect of RAS on GFR :Effect of RAS on GFR


Diagnosis of RAS :Diagnosis of RAS Gold std: angiography Initial non-invasive tests: ACEI renography Duplex sonography Other tests: MRA - insensitive for distal / segmental RAS Captopril test (PRA post-C.) - low sensitivity Renal vein renin levels


ACEI Renography :ACEI Renography


Slide 62:Off ACEI & ATII receptor blockers x 3-7 days Off diuretics x 5-7d No solid food x 4 hrs Patient well hydrated 10 ml/kg water 30-60 min pre- and during test ACEI Captopril 25-50 mg po (crushed), 1 hr pre-scan Enalaprilat 40 µg/kg iv (2.5 mg max), 15 min pre-scan Monitor BP q 15 min ACEI Renography Patient Preparation


ACEI RenographyProcedure :ACEI RenographyProcedure Tracer: Tc-99m MAG3 (or DTPA) Protocol: 1 day vs. 2 day test 1 day test: baseline scan (1-2 mCi) followed by post-Capto scan (8-10 mCi) 2 day test: post-Capto scan, only if abnormal >> baseline Acquisition: flow & dynamic x 20-30 min.


ACEI RenographyProcessing :ACEI RenographyProcessing Relative renal uptake (bkg corrected) Time to peak (Tp) - from cortical ROI normal < 5 min RCA20 (20 min/peak ratio) - from cortical ROI normal < 0.3


Slide 66:ACEI RenographyGrading renogram curves


ACEI RenographyDiagnostic Criteria :ACEI RenographyDiagnostic Criteria MAG3: ipsilateral parenchymal retention p.C. change in renogram curve by  1 grade RCA20 increase by  15% (e.g. from 30% to 45%) Tp increase by  2 min or 40% (e.g. from 5 to 7’) DTPA: ipsilateral decreased uptake Decrease in relative uptake  10% (e.g.from 50/50 to 40/60), change of 5-9% - intermediate change in renogram curve by  2 grades Consens. report JNM ‘96:1876Semin NM 4/99:128-145


ACEI RenographyInterpretation :ACEI RenographyInterpretation High probability RVH (>90%) Marked C-induced change Low probability RVH (<10%) Normal Captopril scan Abnormal baseline, improved p-C. Type I curve - pre- and post-C. Intermediate probability RVH Abnl baseline, no change p-C.


Captopril Renal ScanMAG 3 :Captopril Renal ScanMAG 3


Slide 70:Captopril Renal Scan MAG3


Slide 71:Captopril Renal ScanMAG 3


Slide 73:Captopril Renal ScanMAG 3


ACEI Renography :ACEI Renography In normal renal function - sens/spec ~ 90% In poor renal fct / ischemic nephropathy, ACEI renography often indeterminate >>> do MRA, Duplex US, angio


Evaluation of Renal Infection :Renal Morphology Scan (Renal Cortical Scintigraphy) Evaluation of Renal Infection


UTI :UTI VUR risk factor for PN, not all pts w PN have VUR PN may lead to scarring >>> ESRD, HTN early Dx and Rx necessary Clinical & laboratory Dx of renal involvement in UTI unreliable


Renal Cortical ScintigraphyIndications :Renal Cortical ScintigraphyIndications Determine involvement of upper tract (kidney) in acute UTI (acute pyelonephritis) Detect cortical scarring (chronic pyelonephr.) Follow-up post Rx


Renal Cortical Scintigraphy Procedure :Renal Cortical Scintigraphy Procedure Tracers Tc-99m DMSA Tc-99m GHA Acquisition 2-4 hrs post-injection parallel hole posterior pinhole post. + post. oblique (or SPECT) Processing: relative fct


Renal Cortical ScintigraphyInterpretation :Renal Cortical ScintigraphyInterpretation Acute PN single or multiple “cold” defects renal contour not distorted diffuse decreased uptake diffusely enlarged kidney or focal bulging Chronic PN volume loss, cortical thinning defects with sharp edges Differentiation of AcPN vs. ChPN unreliable


Renal Cortical Scintigraphy“Cold Defect “ :Renal Cortical Scintigraphy“Cold Defect “ Acute or chronic PN Hydronephrosis Cyst Tumors Trauma (contusion, laceration, rupture, hematoma) Infarct


DMSA parallel hole collimator :DMSA parallel hole collimator


Slide 85:Normal DMSA pinhole LPO RPO


DMSA :DMSA


Acute pyelonephritisDMSA :Acute pyelonephritisDMSA post L LPO pinhole post R RPO LEAP


Renal Cortical ScintigraphyCongenital Anomalies :Renal Cortical ScintigraphyCongenital Anomalies Agenesis Ectopy Fusion (horseshoe, crossed fused ectopia) Polycystic kidney Multicystic dysplastic kidney Pseudomasses (fetal lobulation, hypertrophic column of Bertin)


DMSAhorseshoe kidney :DMSAhorseshoe kidney parallel pinhole


DMSALt Agenesis :DMSALt Agenesis parallel


Slide 91:GHACrossed ectopia 74%26%


Radionuclide Cystogram :Radionuclide Cystogram


Indications :Indications Evaluation of children with recurrent UTI 30-50% have VUR F/U after initial VCUG Assess effect of therapy / surgery Screening of siblings of reflux pts.


Methods :Methods Tc-99m S.C. or TcO4 via Foley can do at any age VUR during filling catheterization Tc-99m DTPA or Tc-99m MAG3 i.v. no catheter info on kidneys need pt cooperation need good renal fct Advant. Disadv. Direct Indirect


Direct Cystography :Direct Cystography 1 mCi S.C. in saline via Foley Fill bladder until reversal of flow (bladder capacity = (age+2) x 30 Continuous imaging during filling & voiding Post void image Record volume instilled volume voided pre- and post- void cts


RN Cystogram vs. VCUG :RN Cystogram vs. VCUG Lower radiation dose(5 vs 300 mrad to ovary) Smaller amount of reflux detectable Quantitation of post-void residual volume Cannot detect distal ureteral reflux No anatomic detail Grading difficult Advantages Disadvantages


Normal cystogram :Normal cystogram filling voiding post-void


VUR - filling phase :VUR - filling phase A


VUR - voiding phase & post-void :VUR - voiding phase & post-void B


Post void residual volume :Post void residual volume voided vol x post-void cts pre-void cts - post void cts RV =


Slide 102:Reflux nephropathy 16% 84%