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Renal Renal ScintigraphyScintigraphy
Helena Balon, MDHelena Balon, MDWm. Beaumont HospitalWm. Beaumont Hospital
Royal Oak, MichiganRoyal Oak, MichiganCharles UniversityCharles University
3rd School of Medicine3rd School of Medicine
Dept Nucl Med, PragueDept Nucl Med, Prague
Materials for medical studentsMaterials for medical students
IndicationsIndications
Renal perfusion and functionRenal perfusion and function Obstruction (Lasix renal scan)Obstruction (Lasix renal scan) Renovascular HTN (Captopril renal scan)Renovascular HTN (Captopril renal scan) Infection (renal morphology scan)Infection (renal morphology scan) Pre-surgical quantitation (nephrectomy) Pre-surgical quantitation (nephrectomy) Renal transplantRenal transplant Congenital anomalies, masses Congenital anomalies, masses
(renal morphology scan)(renal morphology scan)
Evaluation of:
Renal FunctionRenal Function
Blood flowBlood flow - 20% cardiac output to kidneys - 20% cardiac output to kidneys (1200 ml/min blood, 600 ml/min plasma)(1200 ml/min blood, 600 ml/min plasma)
FiltrationFiltration - 20% renal plasma flow filtered by - 20% renal plasma flow filtered by glomeruli glomeruli (120 ml/min, 170 L/d)(120 ml/min, 170 L/d)
Tubular secretionTubular secretion Tubular reabsorptionTubular reabsorption (1% ultrafiltrate - urine) (1% ultrafiltrate - urine) EndocrineEndocrine functions functions
Renal RadiotracersRenal Radiotracers
Excretion MechanismsExcretion 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 Renal RadiopharmaceuticalsRadiopharmaceuticals
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 RadiopharmaceuticalsRenal Radiopharmaceuticals
DosimetryDosimetry
DTPA MAG3 GHA DMSA DTPA MAG3 GHA DMSA I-I-
131131OIH OIH rad/10 mCirad/10 mCi rad/5mCi rad/5mCi rad/300µCirad/300µCi
KidneyKidney 0.2 0.2 0.15 0.15 1.61.6 3.5 3.5 0.010.01
BladderBladder2.82.8 5.1 5.1 2.72.7 0.3 0.3 0.30.3
EDE EDE (rem)(rem) 0.30.3 0.4 0.4 0.40.4 0.3 0.3 0.030.03
Choosing Renal Choosing Renal RadiotracersRadiotracers
PerfusionPerfusion MAG3, DTPA, GHAMAG3, DTPA, GHA
MorphologyMorphology DMSA, GHADMSA, GHA
Obstruction Obstruction MAG3, DTPA, OIHMAG3, DTPA, OIH
Relative functionRelative function AllAll
GFR quantitationGFR quantitation I-125 iothalamate, I-125 iothalamate,
Cr-51 EDTA, DTPACr-51 EDTA, DTPA
ERPF quantitationERPF quantitation MAG3, OIHMAG3, OIH
Clin. Question Agent
Basic Renal ScintigraphyBasic Renal Scintigraphy
PatientPatient PreparationPreparation
Patient must be well hydratedPatient must be well hydratedGive 5-10 ml/kg water (2-4 cups) Give 5-10 ml/kg water (2-4 cups)
30-60 min. pre-injection30-60 min. pre-injectionCan measure U - specific gravity (<1.015)Can measure U - specific gravity (<1.015)
Void before injectionVoid before injection Void @ end of studyVoid @ end of study
Int’l Consens. Comm.Int’l Consens. Comm.Semin NM ‘99:146-159Semin NM ‘99:146-159
Basic Renal ScintigraphyBasic Renal Scintigraphy AcquisitionAcquisition
Supine position preferredSupine position preferred Do not inject by straight stickDo not inject by straight stick Flow (angiogram) : 2-3 sec / fr x 1 minFlow (angiogram) : 2-3 sec / fr x 1 min Dynamic: 15-30 sec / frame x 20-30 minDynamic: 15-30 sec / frame x 20-30 min
(display @ 1-3 min/frame)(display @ 1-3 min/frame)
Basic Renal ScintigraphyBasic Renal Scintigraphy Acquisition Acquisition (cont’d)(cont’d)
Obtain a 30-60 sec. image over injection site Obtain a 30-60 sec. image over injection site @ end of study @ end of study if infiltration >0.5% dose if infiltration >0.5% dose do not report do not report
clearanceclearance
Obtain post-void supine image of kidneys Obtain post-void supine image of kidneys @ end of study@ end of study
Taylor, SeminNM 4/99:102-127
International Consensus International Consensus Committee Recommendations for Committee Recommendations for
Basic RenogramBasic Renogram
Tracer: MAG3, (DTPA)Tracer: MAG3, (DTPA) Dose: 2 - 5 mCi adult, minimum 0.5 mCi pedsDose: 2 - 5 mCi adult, minimum 0.5 mCi peds
Pt. position: supine (motion, depth issues)Pt. position: supine (motion, depth issues) Include bladder, heartInclude bladder, heart
Collimator: LEAPCollimator: LEAP
Image over injection siteImage over injection siteInt’l Consens. Comm.Int’l Consens. Comm.Semin NM ‘99:146-159Semin NM ‘99:146-159
Relative uptakeRelative uptake
Contribution of each kidney to the total fctContribution of each kidney to the total fct
net cts in Lt ROInet cts in Lt ROI
% Lt kid% Lt kid = --------------------------------------- x 100% = --------------------------------------- x 100% net cts Lt + net cts Rt ROInet cts Lt + net cts Rt ROI
NormalNormal 50/50 - 56/4450/50 - 56/44BorderlineBorderline 57/43 - 59/4157/43 - 59/41AbnormalAbnormal > 60/40> 60/40
Taylor, SeminNM Apr 99
Basic Renal ScintigraphyBasic Renal Scintigraphy ProcessingProcessing
Time to peakTime to peakBest from cortical ROIBest from cortical ROINormal < 5 minNormal < 5 min
Residual Cortical Activity (RCAResidual Cortical Activity (RCA20 or 3020 or 30))Ratio of cts @ 20 or 30 min / peak ctsRatio of cts @ 20 or 30 min / peak ctsUse cortical ROIUse cortical ROINormal RCANormal RCA2020 for MAG3 < 0.3 for MAG3 < 0.3
Residual Urine VolumeResidual Urine Volume (post-void cts x void. vol) (post-void cts x void. vol) (pre-void cts - post void cts) (pre-void cts - post void cts)
Renogram PhasesRenogram Phases
I.I. Vascular phase Vascular phase (flow study):(flow study):Ao-to-Kid ~ 3”Ao-to-Kid ~ 3”
II.II. Parenchymal phase Parenchymal phase (kidney-to-bkg): (kidney-to-bkg): TTpeakpeak < <
5’5’
III.III. Washout (excretory) phaseWashout (excretory) phase
Evaluation of Evaluation of HydronephrosisHydronephrosis
Diuretic (Lasix) Renal ScanDiuretic (Lasix) Renal Scan
ObstructionObstruction
Obstruction to urine outflow leads to Obstruction to urine outflow leads to obstructive uropathyobstructive uropathy
(hydronephrosis, hydroureter) (hydronephrosis, hydroureter) andand
may lead to may lead to obstructive nephropathyobstructive nephropathy (loss of renal function)(loss of renal function)
Diuretic Renal ScanDiuretic Renal Scan
PrinciplePrinciple Hydronephrosis - tracer pooling in dilated Hydronephrosis - tracer pooling in dilated
renal pelvisrenal pelvis Lasix induces increased urine flowLasix induces increased urine flow If obstructed >>> will not wash outIf obstructed >>> will not wash out If dilated, non-obstructed >>> will wash out If dilated, non-obstructed >>> will wash out
Can quantitate rate of washout (TCan quantitate rate of washout (T1/21/2))
Diuretic Renal ScanDiuretic Renal Scan
IndicationsIndications Evaluate functional significance of Evaluate functional significance of
hydronephrosishydronephrosis
Determine need for surgeryDetermine need for surgeryobstructive hydronephrosis - surgical Rxobstructive hydronephrosis - surgical Rx
non-obstructive hydronephrosis - medical Rxnon-obstructive hydronephrosis - medical Rx
Monitor effect of therapyMonitor effect of therapy
Diuretic Renal ScanDiuretic Renal Scan
RequirementsRequirements
Rapidly cleared tracerRapidly cleared tracer
Well hydrated patientWell hydrated patient
Good renal functionGood renal function
Diuretic Renal ScanDiuretic Renal Scan ProcedureProcedure
Pt. preparation: Pt. preparation: prehydration prehydration
adults - oral or 360ml/madults - oral or 360ml/m2 2 iv over 30’ iv over 30’ peds - 10-15 ml/kg D5 0.3-0.45%NSpeds - 10-15 ml/kg D5 0.3-0.45%NS
void before injectionvoid before injection
bladder catheterization ?bladder catheterization ?
Diuretic Renal ScanDiuretic Renal Scan Procedure Procedure (cont’d)(cont’d)
Tracers: Tracers: Tc-99m MAG3 5-10 mCi Tc-99m MAG3 5-10 mCi (preferred over DTPA) (preferred over DTPA)
Acquisition: supine until pelvis fullAcquisition: supine until pelvis full(can switch to sitting post- Lasix) (can switch to sitting post- Lasix)
Flow (angiogram) : 2-3 sec / fr x 1 minFlow (angiogram) : 2-3 sec / fr x 1 min Dynamic: Dynamic: 15-30 sec / frame x 20-30 min15-30 sec / frame x 20-30 min
Diuretic Renal ScanDiuretic Renal Scan Procedure Procedure (cont’d)(cont’d)
Void before LasixVoid before Lasix
Lasix: Lasix: 40mg adult, 1mg/kg child iv40mg adult, 1mg/kg child iv
@ ~10-20 min (when pelvis full)@ ~10-20 min (when pelvis full)
oror @ -15min (“F-15” method) @ -15min (“F-15” method)
Acquisition for 30 min post LasixAcquisition for 30 min post Lasix
Assess adequacy of diuresis Assess adequacy of diuresis Measure voided volume Measure voided volume
Adults produce ~200-300 ml urine post-LasixAdults produce ~200-300 ml urine post-Lasix
Diuretic Renal ScanDiuretic Renal Scan Procedure Procedure (cont’d)(cont’d)
Don’t give Lasix ifDon’t give Lasix if
Collecting system still fillingCollecting system still filling
Collecting system not full by 60 minCollecting system not full by 60 min
Collecting system drains spontaneouslyCollecting system drains spontaneously
Poor ipsilateral fct (< 20%)Poor ipsilateral fct (< 20%)
Diuretic Renal ScanDiuretic Renal Scan ProcessingProcessing
ROI placementROI placementaround whole kidney around whole kidney ororaround dilated renal collecting system around dilated renal collecting system
T/A curveT/A curve TT1/21/2
from Lasix injection from Lasix injection vs. vs. from diuretic responsefrom diuretic responselinear linear vsvs. exponential fit of washout curve. exponential fit of washout curve
Diuretic Renal ScanDiuretic Renal Scan WashoutWashout
(diuretic response)(diuretic response)
TT1/21/2
time required for 50% tracer to leave time required for 50% tracer to leave the dilated unit the dilated unit
i.e. time required for activity to fall i.e. time required for activity to fall
to 50% of peakto 50% of peak
TT1/21/2 value value Variables influencing TVariables influencing T1/21/2 value: value:
TracerTracerState of hydrationState of hydrationVolume of dilated pelvisVolume of dilated pelvisBladder catheterizationBladder catheterizationDose of LasixDose of LasixRenal function (response to Lasix)Renal function (response to Lasix)ROI (kidney vs. pelvis)ROI (kidney vs. pelvis)TT1/21/2 calculation (from inj. vs. response, curve fit) calculation (from inj. vs. response, curve fit)
TT1/21/2
Normal Normal < 10 min< 10 min Obstructed Obstructed > 20 min> 20 min Indeterminate Indeterminate 10 - 20 min10 - 20 min
Best to obtain own normals for each Best to obtain own normals for each institution, depending on protocol usedinstitution, depending on protocol used
Diuretic Renal ScanDiuretic Renal Scan InterpretationInterpretation
Interpret whole study, not TInterpret whole study, not T1/2 1/2 alone alone
Visual (dynamic images)Visual (dynamic images)
Washout curve shape Washout curve shape (concave vs. convex)(concave vs. convex)
TT1/21/2
Diuretic Renal ScanDiuretic Renal Scan PitfallsPitfalls
False positive for obstructionFalse positive for obstructionDistended bladderDistended bladderGross hydronephrosisGross hydronephrosis
TT(transit time)(transit time) = V = V (volume)(volume) F F (flow)(flow)
Poorly functioning / immature kidneyPoorly functioning / immature kidneyDehydrationDehydration
False negativeFalse negativeLow grade obstructionLow grade obstructionPoorly functioning / immature kidneyPoorly functioning / immature kidney
““F minus 15” F minus 15” Diuretic RenogramDiuretic Renogram
Furosemide (Lasix) injected 15 min Furosemide (Lasix) injected 15 min before before radiopharmaceuticalradiopharmaceutical
Rationale: kidney in maximal diuresis,Rationale: kidney in maximal diuresis,under maximal stressunder maximal stress
Some equivocals will become clearly Some equivocals will become clearly positive, some clearly negativepositive, some clearly negative
English, Br JUrol 1987:10-14Upsdell, Br JUrol 1992:126-132
Captopril Renal ScanCaptopril Renal Scan (ACEI Renography) (ACEI Renography)
Evaluation of Evaluation of Renovascular Renovascular HypertensionHypertension
Renovascular DiseaseRenovascular Disease
Renal artery stenosis (RAS)Renal artery stenosis (RAS)
Ischemic nephropathyIschemic nephropathy
Renovascular hypertension (RVH)Renovascular hypertension (RVH)
RAS RAS RVH RVH
Renovascular Renovascular HypertensionHypertension
Caused by renal hypoperfusionCaused by renal hypoperfusionAtherosclerosisAtherosclerosis
Fibromuscular dysplasiaFibromuscular dysplasia
Mediated by renin - AT - aldosterone systemMediated by renin - AT - aldosterone system
Potentially curable by renal revascularizationPotentially curable by renal revascularization
Renovascular Renovascular HypertensionHypertension
PrevalencePrevalence<1% unselected population with HTN<1% unselected population with HTN
Clinical featuresClinical featuresAbrupt onset HTN in child, adult < 30 or > 50yAbrupt onset HTN in child, adult < 30 or > 50y
Severe HTN resistant to medical RxSevere HTN resistant to medical Rx
Unexplained or post-ACEI impairment in ren fctUnexplained or post-ACEI impairment in ren fct
HTN + abdominal bruitsHTN + abdominal bruits
If these present - moderate risk of RVH (20-30%)If these present - moderate risk of RVH (20-30%)
Renin-Angiotensin SystemRenin-Angiotensin System
RAS
CaptoprilCaptopril
Angiotensinogen
Angiotensin I
Angiotensin II
Aldosterone Vasoconstriction
HTN
Renin
ACE
Diagnosis of RASDiagnosis of RAS
Gold std: angiographyGold std: angiography Initial non-invasive tests:Initial non-invasive tests:
ACEI renographyACEI renography
Duplex sonographyDuplex sonography
Other tests: Other tests: MRA - insensitive for distal / segmental RASMRA - insensitive for distal / segmental RAS
Captopril test (PRA post-C.) - low sensitivityCaptopril test (PRA post-C.) - low sensitivity
Renal vein renin levelsRenal vein renin levels
Off ACEI & ATII receptor blockers x 3-7 days Off ACEI & ATII receptor blockers x 3-7 days
Off diuretics x 5-7dOff diuretics x 5-7d
No solid food x 4 hrsNo solid food x 4 hrs
Patient well hydratedPatient well hydrated 10 ml/kg water 30-60 min pre- and during test10 ml/kg water 30-60 min pre- and during test
ACEIACEI Captopril 25-50 mg po (crushed), 1 hr pre-scanCaptopril 25-50 mg po (crushed), 1 hr pre-scan
Enalaprilat 40 µg/kg iv (2.5 mg max), 15 min pre-scanEnalaprilat 40 µg/kg iv (2.5 mg max), 15 min pre-scan
Monitor BP q 15 minMonitor BP q 15 min
ACEI Renography ACEI Renography
Patient PreparationPatient Preparation
ACEI RenographyACEI Renography
ProcedureProcedure
Tracer: Tracer: Tc-99m MAG3 (or DTPA)Tc-99m MAG3 (or DTPA) Protocol: Protocol: 1 day 1 day vsvs. 2 day test. 2 day test
1 day test: 1 day test: baseline scan (1-2 mCi) followed by baseline scan (1-2 mCi) followed by post-Capto scan (8-10 mCi)post-Capto scan (8-10 mCi)
2 day test: 2 day test: post-Capto scan, post-Capto scan, only if abnormal >> baseline only if abnormal >> baseline
Acquisition: Acquisition: flow & dynamic x 20-30 min.flow & dynamic x 20-30 min.
ACEI RenographyACEI Renography
ProcessingProcessing
Relative renal uptake (bkg corrected)Relative renal uptake (bkg corrected)
Time to peak (TTime to peak (Tpp) - from cortical ROI) - from cortical ROInormal < 5 minnormal < 5 min
RCARCA2020 (20 min/peak ratio) - from cortical ROI (20 min/peak ratio) - from cortical ROInormal < 0.3normal < 0.3
ACEI RenographyACEI Renography
Diagnostic CriteriaDiagnostic Criteria MAG3:MAG3: ipsilateral parenchymal retention ipsilateral parenchymal retention
p.C.p.C. change in renogram curve by change in renogram curve by 1 grade 1 grade
RCARCA20 20 increase by increase by 15% (e.g. from 30% to 45%) 15% (e.g. from 30% to 45%)
TTp p increase by increase by 2 min or 40% (e.g. from 5 to 7’) 2 min or 40% (e.g. from 5 to 7’)
DTPA:DTPA: ipsilateral decreased uptake ipsilateral decreased uptake Decrease in relative uptake Decrease in relative uptake 10% 10%
(e.g.from 50/50 to 40/60), change of 5-9% - intermediate(e.g.from 50/50 to 40/60), change of 5-9% - intermediate
change in renogram curve by change in renogram curve by 2 grades 2 gradesConsens. report JNM ‘96:1876Semin NM 4/99:128-145
ACEI RenographyACEI Renography
InterpretationInterpretation
High probability RVH (>90%)High probability RVH (>90%)Marked C-induced changeMarked C-induced change
Low probability RVH (<10%)Low probability RVH (<10%)Normal Captopril scanNormal Captopril scan
Abnormal baseline, improved p-C.Abnormal baseline, improved p-C.
Type I curve - pre- and post-C. Type I curve - pre- and post-C.
Intermediate probability RVHIntermediate probability RVHAbnl baseline, no change p-C. Abnl baseline, no change p-C.
ACEI RenographyACEI Renography
In normal renal function - sens/spec ~ 90%In normal renal function - sens/spec ~ 90% In poor renal fct / ischemic nephropathy, In poor renal fct / ischemic nephropathy,
ACEI renography often indeterminate ACEI renography often indeterminate >>> do MRA, Duplex US, angio>>> do MRA, Duplex US, angio
Renal Morphology Scan Renal Morphology Scan (Renal Cortical (Renal Cortical Scintigraphy)Scintigraphy)
Evaluation of Renal Evaluation of Renal InfectionInfection
UTIUTI
VURVURrisk factor for PN, risk factor for PN,
not all pts w PN have VUR not all pts w PN have VUR
PN may lead to scarring >>> ESRD, HTNPN may lead to scarring >>> ESRD, HTNearly Dx and Rx necessaryearly Dx and Rx necessary
Clinical & laboratory Dx of renal involvement Clinical & laboratory Dx of renal involvement in UTI unreliablein UTI unreliable
Renal Cortical ScintigraphyRenal Cortical Scintigraphy
IndicationsIndications
Determine involvement of upper tractDetermine involvement of upper tract
(kidney) in acute UTI (acute pyelonephritis) (kidney) in acute UTI (acute pyelonephritis)
Detect cortical scarring (chronic pyelonephr.)Detect cortical scarring (chronic pyelonephr.)
Follow-up post RxFollow-up post Rx
Renal Cortical ScintigraphyRenal Cortical Scintigraphy
ProcedureProcedure Tracers Tracers
Tc-99m DMSA Tc-99m DMSA Tc-99m GHATc-99m GHA
AcquisitionAcquisition2-4 hrs post-injection2-4 hrs post-injectionparallel hole posteriorparallel hole posteriorpinhole post. + post. oblique (or SPECT)pinhole post. + post. oblique (or SPECT)
Processing: relative fctProcessing: relative fct
Renal Cortical ScintigraphyRenal Cortical Scintigraphy
InterpretationInterpretation Acute PNAcute PN
single or multiple “cold” defectssingle or multiple “cold” defectsrenal contour not distortedrenal contour not distorteddiffuse decreased uptakediffuse decreased uptakediffusely enlarged kidney or focal bulgingdiffusely enlarged kidney or focal bulging
Chronic PNChronic PNvolume loss, cortical thinningvolume loss, cortical thinningdefects with sharp edgesdefects with sharp edges
Differentiation of AcPNDifferentiation of AcPN vs vs. ChPN unreliable. ChPN unreliable
Renal Cortical ScintigraphyRenal Cortical Scintigraphy
“Cold Defect ““Cold Defect “
Acute or chronic PNAcute or chronic PN HydronephrosisHydronephrosis CystCyst TumorsTumors Trauma (contusion, laceration, rupture, Trauma (contusion, laceration, rupture,
hematoma)hematoma) InfarctInfarct
Renal Cortical ScintigraphyRenal Cortical Scintigraphy
Congenital AnomaliesCongenital Anomalies
AgenesisAgenesis EctopyEctopy Fusion Fusion (horseshoe, crossed fused ectopia)(horseshoe, crossed fused ectopia)
Polycystic kidneyPolycystic kidney Multicystic dysplastic kidneyMulticystic dysplastic kidney Pseudomasses Pseudomasses (fetal lobulation, hypertrophic (fetal lobulation, hypertrophic
column of Bertin)column of Bertin)
IndicationsIndications
Evaluation of children with recurrent UTIEvaluation of children with recurrent UTI30-50% have VUR30-50% have VUR
F/U after initial VCUGF/U after initial VCUG Assess effect of therapy / surgeryAssess effect of therapy / surgery Screening of siblings of reflux pts.Screening of siblings of reflux pts.
MethodsMethods
Tc-99m S.C. or Tc-99m S.C. or TcO4TcO4
via Foleyvia Foley
can do at any agecan do at any age VUR during fillingVUR during filling
catheterizationcatheterization
Tc-99m DTPA or Tc-99m DTPA or Tc-99m MAG3Tc-99m MAG3
i.v.i.v.
no catheterno catheter info on kidneysinfo on kidneys
need pt need pt cooperationcooperation
need good renal need good renal fctfct
Advant.Advant.
Disadv.Disadv.
Direct Indirect
Direct CystographyDirect Cystography
1 mCi S.C. in saline via Foley1 mCi S.C. in saline via Foley Fill bladder until reversal of flowFill bladder until reversal of flow
(bladder capacity = (age+2) x 30(bladder capacity = (age+2) x 30 Continuous imaging during filling & Continuous imaging during filling &
voidingvoiding Post void imagePost void image RecordRecord
volume instilled volume instilled volume voidedvolume voidedpre- and post- void ctspre- and post- void cts
RN Cystogram vs. RN Cystogram vs. VCUGVCUG
Lower radiation Lower radiation dosedose(5 (5 vs vs 300 mrad to 300 mrad to ovary)ovary)
Smaller amount of Smaller amount of reflux detectablereflux detectable
Quantitation of Quantitation of post-void residual post-void residual volumevolume
Cannot detect distal Cannot detect distal ureteral refluxureteral reflux
No anatomic detailNo anatomic detail Grading difficult Grading difficult
Advantages Disadvantages
Post void residual Post void residual volumevolume
voided vol x post-void ctsvoided vol x post-void cts
pre-void cts - post void ctspre-void cts - post void ctsRV =RV =