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Renal Scintigraphy. Materials for medical students. Helena Balon, MD Wm. Beaumont Hospital Royal Oak, Michigan Charles University 3rd School of Medicine Dept Nucl Med, Prague. Renal perfusion and function Obstruction (Lasix renal scan) Renovascular HTN (Captopril renal scan)

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Renal scintigraphy l.jpg

Renal Scintigraphy

Materials for medical students

Helena Balon, MD

Wm. Beaumont Hospital

Royal Oak, Michigan

Charles University

3rd School of Medicine

Dept Nucl Med, Prague


Indications l.jpg

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)

Indications

Evaluation of:


Renal function l.jpg
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 radiotracers excretion mechanisms l.jpg
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 DMSAsome 60%

Semin NM Apr.92


Renal radiopharmaceuticals l.jpg
Renal Radiopharmaceuticals

Extract. fractionClearance

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 radiopharmaceuticals dosimetry l.jpg
Renal RadiopharmaceuticalsDosimetry

DTPA MAG3 GHA DMSA I-131OIH rad/10 mCirad/5mCi rad/300µCi

Kidney 0.2 0.15 1.6 3.5 0.01

Bladder 2.85.1 2.7 0.3 0.3

EDE (rem) 0.3 0.4 0.4 0.3 0.03


Choosing renal radiotracers l.jpg

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

Choosing Renal Radiotracers

Clin. Question Agent



Basic renal scintigraphy patient preparation l.jpg
Basic Renal ScintigraphyPatientPreparation

  • 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 l.jpg
Basic Renal ScintigraphyAcquisition

  • 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 l.jpg
Basic Renal ScintigraphyAcquisition (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 l.jpg
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 l.jpg
DTPA normal Renogram


Dtpa normal14 l.jpg
DTPA normal Renogram


Relative split function roi s l.jpg
Relative (split) function RenogramROI’s


Relative uptake l.jpg
Relative uptake Renogram

  • 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 l.jpg
Basic Renal Scintigraphy RenogramProcessing

  • 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)


Slide18 l.jpg

DTPA flow + scan Renogram

GFR = 29 ml/’

Creat = 2.0

L= 33%

R= 67%




Renogram phases l.jpg
Renogram Phases Renogram

  • I. Vascular phase (flow study): Ao-to-Kid ~ 3”

  • II. Parenchymal phase (kidney-to-bkg): Tpeak < 5’

  • III. Washout (excretory) phase


Renogram curves l.jpg
Renogram curves Renogram


Evaluation of hydronephrosis l.jpg
Evaluation of Hydronephrosis Renogram

Diuretic (Lasix) Renal Scan


Obstruction l.jpg
Obstruction Renogram

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


Diuretic renal scan principle l.jpg
Diuretic Renal Scan RenogramPrinciple

  • 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 l.jpg
Diuretic Renal Scan RenogramIndications

  • 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 l.jpg
Diuretic Renal Scan RenogramRequirements

  • Rapidly cleared tracer

  • Well hydrated patient

  • Good renal function


Diuretic renal scan procedure l.jpg
Diuretic Renal Scan RenogramProcedure

  • 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 l.jpg
Diuretic Renal Scan RenogramProcedure (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 d30 l.jpg
Diuretic Renal Scan RenogramProcedure (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 d31 l.jpg
Diuretic Renal Scan RenogramProcedure (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 l.jpg
pre-Lasix Renogram


Post lasix l.jpg
post-Lasix Renogram


No upj obstruction l.jpg
No UPJ obstruction Renogram

T1/2

R = 6’

L = 2’



Pre lasix36 l.jpg
Pre-Lasix Renogram

10 y/o M


Post lasix37 l.jpg
Post-Lasix Renogram


Rt upj obstruction l.jpg
Rt UPJ obstruction Renogram

T1/2

R = N/A

F/U - nephrostomy tube placed


Slide39 l.jpg

Lt hydronephrosis Renogram

3-wk old baby

3164897


Slide40 l.jpg

Lt UPJ obstruction Renogram

3164897


Rt upj obstruction41 l.jpg
Rt UPJ obstruction Renogram

T1/2

R = N/A

F/U - nephrostomy tube placed


Slide42 l.jpg

Lt UPJ obstruction Renogram

3164897


Diuretic renal scan processing l.jpg
Diuretic Renal Scan RenogramProcessing

  • 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 l.jpg
Diuretic Renal Scan RenogramWashout(diuretic response)

T1/2time required for 50% tracer to leave the dilated unit i.e. time required for activity to fall

to 50% of peak


T 1 2 washout l.jpg
T Renogram1/2 washout

cts

100%

50%

T1/2 min


T 1 2 value l.jpg
T Renogram1/2 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)


T 1 2 l.jpg
T Renogram1/2

  • Normal < 10 min

  • Obstructed > 20 min

  • Indeterminate 10 - 20 min

  • Best to obtain own normals for each institution, depending on protocol used


Diuretic renal scan interpretation l.jpg
Diuretic Renal Scan RenogramInterpretation

  • Interpret whole study, not T1/2 alone

  • Visual (dynamic images)

  • Washout curve shape (concave vs. convex)

  • T1/2


Diuretic renal scan pitfalls l.jpg
Diuretic Renal Scan RenogramPitfalls

  • 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 l.jpg
Effect of catheterization Renogram(1)

full bladder,no catheter


Effect of catheterization 2 l.jpg
Effect of catheterization Renogram(2)

with catheter in bladder


Effect of catheterization 3 l.jpg
Effect of catheterization Renogram(3)

without catheter

with catheter


F minus 15 diuretic renogram l.jpg
“F minus 15” RenogramDiuretic 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 l.jpg
Evaluation of Renovascular Hypertension Renogram

Captopril Renal Scan (ACEI Renography)


Renovascular disease l.jpg
Renovascular Disease Renogram

  • Renal artery stenosis (RAS)

  • Ischemic nephropathy

  • Renovascular hypertension (RVH)

    RAS  RVH


Renovascular hypertension l.jpg
Renovascular Hypertension Renogram

  • Caused by renal hypoperfusion

    • Atherosclerosis

    • Fibromuscular dysplasia

  • Mediated by renin - AT - aldosterone system

  • Potentially curable by renal revascularization


Renovascular hypertension57 l.jpg
Renovascular Hypertension Renogram

  • Prevalence

    • <1% unselected population with HTN

  • Clinical features

    • Abrupt onset HTN in child, adult < 30 or > 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 l.jpg
Renin-Angiotensin System Renogram

RAS

Angiotensinogen

Renin

Angiotensin I

Captopril

ACE

Angiotensin II

Aldosterone Vasoconstriction

HTN



Diagnosis of ras l.jpg
Diagnosis of RAS Renogram

  • 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 l.jpg
ACEI Renography Renogram


Slide62 l.jpg

ACEI Renography RenogramPatient Preparation

  • 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 procedure l.jpg
ACEI Renography RenogramProcedure

  • 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 renography processing l.jpg
ACEI Renography RenogramProcessing

  • 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


Slide66 l.jpg

ACEI Renography RenogramGrading renogram curves


Acei renography diagnostic criteria l.jpg
ACEI Renography RenogramDiagnostic 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 renography interpretation l.jpg
ACEI Renography RenogramInterpretation

  • 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 scan mag 3 l.jpg
Captopril Renal Scan RenogramMAG 3



Slide71 l.jpg

Captopril Renal Scan RenogramMAG 3


Slide73 l.jpg

Captopril Renal Scan RenogramMAG 3


Acei renography77 l.jpg
ACEI Renography Renogram

  • 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 l.jpg
Evaluation of Renal Infection Renogram

Renal Morphology Scan (Renal Cortical Scintigraphy)


Slide79 l.jpg
UTI Renogram

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 scintigraphy indications l.jpg
Renal Cortical Scintigraphy RenogramIndications

Determine involvement of upper tract (kidney) in acute UTI (acute pyelonephritis)

Detect cortical scarring (chronic pyelonephr.)

Follow-up post Rx


Renal cortical scintigraphy procedure l.jpg
Renal Cortical Scintigraphy RenogramProcedure

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 scintigraphy interpretation l.jpg
Renal Cortical Scintigraphy RenogramInterpretation

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 l.jpg
Renal Cortical Scintigraphy Renogram“Cold Defect “

Acute or chronic PN

Hydronephrosis

Cyst

Tumors

Trauma (contusion, laceration, rupture, hematoma)

Infarct


Dmsa parallel hole collimator l.jpg
DMSA Renogramparallel hole collimator


Slide85 l.jpg

Normal DMSA Renogram

pinhole

LPO RPO


Slide86 l.jpg
DMSA Renogram


Acute pyelonephritis dmsa l.jpg
Acute pyelonephritis RenogramDMSA

post L

postR

LEAP

LPO pinhole

RPO


Renal cortical scintigraphy congenital anomalies l.jpg
Renal Cortical Scintigraphy RenogramCongenital Anomalies

Agenesis

Ectopy

Fusion (horseshoe, crossed fused ectopia)

Polycystic kidney

Multicystic dysplastic kidney

Pseudomasses (fetal lobulation, hypertrophic column of Bertin)


Dmsa horseshoe kidney l.jpg
DMSA Renogramhorseshoe kidney

parallel pinhole


Dmsa lt agenesis l.jpg
DMSA RenogramLt Agenesis

parallel


Slide91 l.jpg

GHA RenogramCrossed ectopia

74%26%



Indications94 l.jpg
Indications Renogram

  • 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 l.jpg

Tc-99m S.C. or TcO4 Renogram

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

Methods

DirectIndirect

Advant.

Disadv.


Direct cystography l.jpg
Direct Cystography Renogram

  • 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 l.jpg

Lower radiation dose Renogram(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

RN Cystogram vs. VCUG

AdvantagesDisadvantages


Normal cystogram l.jpg
Normal cystogram Renogram

filling voiding post-void



Vur voiding phase post void l.jpg
VUR - Renogramvoiding phase & post-void

B


Post void residual volume l.jpg
Post void residual volume Renogram

voided vol x post-void cts pre-void cts - post void cts

RV =


Slide102 l.jpg

Reflux nephropathy Renogram

16%

84%


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