Nuclear imaging in kidney disease

USE OF NUCLEAR USE OF NUCLEAR IMAGING IN KIDNEY IMAGING IN KIDNEY

DISEASES : DISEASES : INDICATIONS AND INDICATIONS AND INTERPRETATIONSINTERPRETATIONS

20-5-1320-5-13

IsotopesIsotopes

Any given element may have many isotopesAny given element may have many isotopes All isotopes of a given element have the same All isotopes of a given element have the same

no of protons and differ only in the no of no of protons and differ only in the no of neutronsneutrons

Some of these isotopes have unstable nuclear Some of these isotopes have unstable nuclear configuration and seek greater stability by configuration and seek greater stability by decay/disintegration to a more stable formdecay/disintegration to a more stable form

Isotopes attempting to reach stability by Isotopes attempting to reach stability by emitting radiation are called emitting radiation are called radionuclides/radioisotopesradionuclides/radioisotopes

RadionuclidesRadionuclides

Photon Emitting(imaging) – TcPhoton Emitting(imaging) – Tc99m99m; ; MoMo9999;I;I123123;Ga;Ga6767;In;In113113;Kr;Kr8181;Th;Th201201

Positron Emitting(imaging) Positron Emitting(imaging) CC1111;N;N1313;O;O1515;F;F1818;Rb;Rb8282

Used for therapy- Used for therapy- PP3232;Sr;Sr8989;Y;Y9090;I;I131131;Sm;Sm153153

Radionuclides for Radionuclides for ImagingImaging

Desirable characteristics Desirable characteristics

Minimum particulate emissionMinimum particulate emission

Primary photon energy between 50-500 keVPrimary photon energy between 50-500 keV

Physical T1/2 > time reqd to prepare Physical T1/2 > time reqd to prepare materialmaterial

Effective T1/2 longer than examination timeEffective T1/2 longer than examination time

Low toxicityLow toxicity

Stability or near stability of the productStability or near stability of the product

TechnetiumTechnetium99m99m

Fulfills many criteria of ideal Fulfills many criteria of ideal radionuclideradionuclide

No particulate emissionNo particulate emission 6 hour half life6 hour half life A predominant (98%) 148KeV A predominant (98%) 148KeV

photon conversionphoton conversion Used in > 70% of nuclear imaging Used in > 70% of nuclear imaging

procedures in United Statesprocedures in United States

Nuclear medicineNuclear medicine is a branch of is a branch of medicinemedicine and and imagingimaging that uses that uses radionuclides and relies on the radionuclides and relies on the process of process of radioactive decayradioactive decay in the in the diagnosis and treatment of disease.diagnosis and treatment of disease.

Used in Nephro-Urology since Used in Nephro-Urology since 1960s1960s

Functional and anatomic informationFunctional and anatomic information

More organ / tissue specific c/t whole More organ / tissue specific c/t whole body scansbody scans

RADIOPHARMACEUTICALS = RADIOPHARMACEUTICALS = RADIONUCLIDES + PHARMACEUTICALRADIONUCLIDES + PHARMACEUTICAL

NUCLEAR NUCLEAR SCINTIGRAPHYSCINTIGRAPHY

TECHNIQUESTECHNIQUES 2D2D Scintigraphy - use of internal radionuclides - use of internal radionuclides

to create two-dimensionalto create two-dimensional images.images.

3D3D SPECT - tomographic technique using - tomographic technique using gamma camera data from many projections gamma camera data from many projections and reconstructed in different planesand reconstructed in different planes

HYBRID SCAN HYBRID SCAN - SPECT/CT and PET/CT- SPECT/CT and PET/CT

TOPICSTOPICS Renal ScintigraphyRenal Scintigraphy

ACEI renal scanACEI renal scan

Renal Transplant Scintigraphy

Radionuclide cystogramRadionuclide cystogram

Renal scintigraphy Renal scintigraphy

INDICATIONSINDICATIONS Renal perfusion and functionRenal perfusion and function Urinary Tract Obstruction (Furosemide renal Urinary Tract Obstruction (Furosemide renal

scan)scan) Reno-vascular HTN (Captopril renal scan)Reno-vascular HTN (Captopril renal scan) Infection (renal morphology Infection (renal morphology

scan)scan) Pre-surgical quantitation (nephrectomy) Pre-surgical quantitation (nephrectomy) Renal transplantationRenal transplantation Congenital anomalies/masses(renal morphology Congenital anomalies/masses(renal morphology

scan)scan)

Radiopharmaceutical Radiopharmaceutical AgentsAgents

Grouped into three categories: Grouped into three categories:

1.1. Those excreted by glomerular Those excreted by glomerular filtration,filtration,

1.1. Those excreted by tubular secretion, Those excreted by tubular secretion, andand

2.2. Those retained in the renal tubules for Those retained in the renal tubules for long periods long periods

Radiopharmaceutical Radiopharmaceutical AgentsAgents

Glomerular AgentsGlomerular Agents

Tc 99m DTPATc 99m DTPA

5151Cr-EDTACr-EDTA

I 125 IothalamateI 125 Iothalamate

Glomerular Filtrating AgentsGlomerular Filtrating AgentsTc-99m DTPA Tc-99m DTPA

(Diethylenetriamine pentaacetic (Diethylenetriamine pentaacetic acid)acid) COOH COOH N

N

N COOH

COOH

HOOC

Tc 99m DTPATc 99m DTPA

• Inulin clearance remains the gold Inulin clearance remains the gold standard to measure GFR, but it is standard to measure GFR, but it is expensive, time consuming, and requires a expensive, time consuming, and requires a steady-state plasma concentration and steady-state plasma concentration and accurate and timed urine collectionaccurate and timed urine collection

• 99m99mTc-DTPA is recommended agent is for Tc-DTPA is recommended agent is for GFR measurement.GFR measurement.

• 5- 10% plasma protein binding, so it tends 5- 10% plasma protein binding, so it tends to underestimate the GFR(insignificant)to underestimate the GFR(insignificant)

• Peak renal activity after 3 – 4 min.Peak renal activity after 3 – 4 min.• 90 % filtered within 4 hours.90 % filtered within 4 hours.• The extraction fraction of The extraction fraction of 99m99mTc-DTPA is Tc-DTPA is

approximately 20 per cent; for this approximately 20 per cent; for this reason, not useful for imaging , in reason, not useful for imaging , in patients with patients with impaired renal functionimpaired renal function..

• In such cases, agents with higher In such cases, agents with higher extraction efficiencies such as extraction efficiencies such as 99m99mTc-Tc-MAG3 more appropriate.MAG3 more appropriate.

5151Cr-EDTA, which may provide more Cr-EDTA, which may provide more accurate values for GFR, but accurate values for GFR, but cannot cannot be used for imaging.be used for imaging.

Tubular secreting agents:Tubular secreting agents:

I131/I123 OIHI131/I123 OIH Tc99m MAG3Tc99m MAG3 Tc99m ECTc99m EC

Proximal convoluted tubules

p-Aminohippuric acid (PAH) is the p-Aminohippuric acid (PAH) is the gold standard for the measurement gold standard for the measurement of ERPF. of ERPF.

However, it is not well suited for However, it is not well suited for routine studies.routine studies.

I-131/I-123 I-131/I-123 OrthoiodohippurateOrthoiodohippurate

-C-NH-CH2-COOH

O

I

Chemical structure similar to the Paraaminohippuric acid

I-131 OIHI-131 OIH

Secreted by tubules – 80% & Secreted by tubules – 80% & glomerular filtration - 20%glomerular filtration - 20%

Chemically & pharmacokinetically Chemically & pharmacokinetically similar to PAHsimilar to PAH

Plasma protein binding – 70%Plasma protein binding – 70%

Cortical peak time = 3-5 minCortical peak time = 3-5 min

Radiation absorbed dose to Radiation absorbed dose to bladder= 0.74 rad/mCibladder= 0.74 rad/mCi

The main disadvantages of The main disadvantages of 131131I-OIH I-OIH are the suboptimal imaging are the suboptimal imaging characteristics of characteristics of 131131I.I.

123123I-OIH has better imaging qualities, I-OIH has better imaging qualities, but but 123123I is more expensive and less I is more expensive and less available.available.

TcTc99m99m MAG3 MAG3(Mercaptoacetyl triglycine)(Mercaptoacetyl triglycine)

S O N

Tc

N N

O

O

CH2-COO

TcTc99m99m MAG3 MAG3

70 – 90 % PROTEIN BINDING70 – 90 % PROTEIN BINDING 89% TUBULAR SECRETION89% TUBULAR SECRETION 11% 11% GLOMERULARGLOMERULAR FILTRATION FILTRATION Extraction fraction of 40-50%.Extraction fraction of 40-50%. Provides a high target-to-background Provides a high target-to-background

ratio, good image quality, and more ratio, good image quality, and more accurate numerical values, particularly accurate numerical values, particularly when the kidney function is low or when the kidney function is low or immature immature

5 TO 10 mCi i.v. ( ADULTS) 5 TO 10 mCi i.v. ( ADULTS)

TcTc99m99m L,L-EC L,L-EC(Ethylene dicysteine)(Ethylene dicysteine)

N NN N

-ooc coo--ooc coo-

TcTc

S SS S

Exists in 4 different forms D,D-EC; L,L-EC; D,L-EC & L,D-EC

EC:EC:

Metabolite of the L,L-ECD(ethylene Metabolite of the L,L-ECD(ethylene cystine dimer) with cortical uptakecystine dimer) with cortical uptake

Secretion in proximal convoluted Secretion in proximal convoluted tubulestubules

Plasma protein binding is 50%Plasma protein binding is 50% Exact excretion mechanism is not Exact excretion mechanism is not

knownknown Clearance is 69-85% of OIHClearance is 69-85% of OIH

Cortical Binding Agents:Cortical Binding Agents:

Tc99m DMSATc99m DMSA

Tc99m GHATc99m GHA

Tc-99m DMSA Tc-99m DMSA (Dimercaptosuccinic Acid)(Dimercaptosuccinic Acid)

H

HS COOH

HS COOH

H

Cortical agentsCortical agents TcTc99m99m DMSA- DMSA-PYELONEPHRITIS, INFARCTS, SCARS, PYELONEPHRITIS, INFARCTS, SCARS,

ANOMALIESANOMALIES 75% protien binding in 6 hrs75% protien binding in 6 hrs 5- 20 % excretion 2 hrs5- 20 % excretion 2 hrs 37% excretion in 24 hrs37% excretion in 24 hrs 40-50% cortical localisation40-50% cortical localisation Maximum activity at 3-6 hrs Maximum activity at 3-6 hrs 2 TO 5 mCi i.v.2 TO 5 mCi i.v. Images at 2 – 4 hrsImages at 2 – 4 hrs

Importantly, acute infection can Importantly, acute infection can produce abnormalities in the scan; produce abnormalities in the scan; and if the test is being performed to and if the test is being performed to evaluate for cortical scarring, it evaluate for cortical scarring, it should be done at least 3 months should be done at least 3 months after an acute infection ( Rosenberg after an acute infection ( Rosenberg et al, 1992 ). et al, 1992 ).

Tc 99m GHATc 99m GHA(Glucoheptonate)(Glucoheptonate)

O O O

C Tc C

CH CH O O (CHOH)4

CH2OH CH2OH

(CHOH)4

OO

CONTD..CONTD..

Tc 99m GHTc 99m GH It is both filtered by the glomerulus and It is both filtered by the glomerulus and

bound by the tubules.bound by the tubules. Glomerular filtration 80-90%Glomerular filtration 80-90% Tubular secretion 10-20%Tubular secretion 10-20% 25-40% in 1 hr & 70% in 24 hrs in urine25-40% in 1 hr & 70% in 24 hrs in urine 15% bound to PCT15% bound to PCT EARLY DYNAMIC FUNCTIONAL imagingEARLY DYNAMIC FUNCTIONAL imaging

DELAYED CORTICAL imagingDELAYED CORTICAL imaging 10-15 mCi10-15 mCi

Choosing Renal Choosing Renal RadiotracersRadiotracers

PerfusionPerfusion MAG3, DTPA, GHAMAG3, DTPA, GHA

MorphologyMorphology DMSA, GHA DMSA, GHA

Obstruction Obstruction MAG3, DTPA, OIHMAG3, DTPA, OIH

GFR quantitationGFR quantitation I-125 I-125 iothalamate, iothalamate,

Cr-51 EDTA, DTPACr-51 EDTA, DTPA

ERPF quantitationERPF quantitation MAG3, OIH MAG3, OIH

Clin. Question Agent

Basic Renal ScanBasic Renal Scan

ProcedureProcedure

Basic Renal ScintigraphyBasic Renal Scintigraphy

PatientPatient PreparationPreparation

Patient must be well hydratedPatient must be well hydrated Give 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-injection Can measure U - specific gravity Can measure U - specific gravity

(<1.015)(<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 Flow (angiogram) : 2-3 sec / fr x 1 Flow (angiogram) : 2-3 sec / fr x 1

minmin Dynamic: 15-30 sec / frame x 20-Dynamic: 15-30 sec / frame x 20-

30 min30 min (display @ 1-3 (display @ 1-3

min/frame)min/frame)

Basic Renal ScintigraphyBasic Renal Scintigraphy Acquisition Acquisition (cont’d)(cont’d)

Obtain a 30-60 sec. image over injection Obtain a 30-60 sec. image over injection site @ end of study site @ 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 Committee International Consensus Committee Recommendations for Basic Recommendations for Basic

RenogramRenogram

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 site

Int’l Consens. Comm.Int’l Consens. Comm.Semin NM ‘99:146-159Semin NM ‘99:146-159

Radionuclide Renal Radionuclide Renal EvaluationEvaluation

Functional Imaging(visual Functional Imaging(visual assessment of perfusion and assessment of perfusion and function)function)

Renography (time activity curve Renography (time activity curve representative of renal function)representative of renal function)

Quantification of renal function(GFR Quantification of renal function(GFR & ERPF)& ERPF)

Anatomic imaging( cortical imaging)Anatomic imaging( cortical imaging)

Functional ImagingFunctional Imaging Perfusion imaging Perfusion imaging –– Evaluation of renal blood flow and Evaluation of renal blood flow and

function of native kidneys – posterior function of native kidneys – posterior projection ; transplanted kidneys – projection ; transplanted kidneys – anterior projectionanterior projection

10-20mCi of radiopharmaceutical injected 10-20mCi of radiopharmaceutical injected iv in antecubital vein.iv in antecubital vein.

Imaging renal perfusion is usually begun Imaging renal perfusion is usually begun as soon as bolus is seen in abd. Aortaas soon as bolus is seen in abd. Aorta

Subsequent images are taken every 1-5 Subsequent images are taken every 1-5 secssecs

In normal renal blood flowIn normal renal blood flow

By 3 sec aorta is fully visualized.By 3 sec aorta is fully visualized.

By 5-6 sec, both kidneys are seen.By 5-6 sec, both kidneys are seen.

Maximal kidney activity is reached Maximal kidney activity is reached in 30-60 sec.in 30-60 sec.

DTPA normalDTPA normal

Renal functional imagingRenal functional imaging

At the end of perfusion sequence , At the end of perfusion sequence , imaging for function begins.imaging for function begins.

Dynamic or sequential static; 3-5 Dynamic or sequential static; 3-5 min Tcmin Tc99m 99m DTPA or MAG3 are then DTPA or MAG3 are then obtained over 20-30 mins.obtained over 20-30 mins.

Evaluation is similar to an IVP with – Evaluation is similar to an IVP with – anatomy, position, symmetry and anatomy, position, symmetry and adequacy of function & collecting adequacy of function & collecting system patency. system patency.

With TcWith Tc99m99m MAG3 maximal MAG3 maximal parenchymal activity is seen at 3-5 parenchymal activity is seen at 3-5 min min

Activity in collecting system and Activity in collecting system and bladder by 4-8 mins.bladder by 4-8 mins.

DTPA normalDTPA normal

RenographyRenography

A Time Activity CurveA Time Activity Curve

Graphic representation of uptake Graphic representation of uptake and excretion of and excretion of radiopharmaceuticalradiopharmaceutical

Information is displayed from time of Information is displayed from time of injection to abt 20-30 mins injection to abt 20-30 mins

Renogram PhasesRenogram Phases FLOW / VASCULAR FLOW / VASCULAR

PHASE PHASE

(RADIONUCLETIDE (RADIONUCLETIDE

ANGIOGRAM)ANGIOGRAM)

• Last for 30-60 sec.Last for 30-60 sec.

• Max activity 4-6 Max activity 4-6

secs after peak secs after peak

aortic activityaortic activity

FUNCTIONAL PHASE FUNCTIONAL PHASE

( 30 MIN )( 30 MIN )

II.II. Parenchymal Parenchymal

phase(uptakephase(uptake))

• Max activity 3to 5 minMax activity 3to 5 min

• UPTAKE AT 2 TO 3 MIN UPTAKE AT 2 TO 3 MIN

FOR SPLIT FUNCTIONFOR SPLIT FUNCTION

III.III. Washout (excretory) phaseWashout (excretory) phase

no activity after 30 minno activity after 30 min

RENOGRAM PHASES

Data obtained from Data obtained from renogramrenogram

Time to peak cortical activity- 3-5Time to peak cortical activity- 3-5 min min

Half-time excretion- time for half of Half-time excretion- time for half of peak activity to be cleared from kidney. peak activity to be cleared from kidney. N – 8-12 minsN – 8-12 mins

Cortical activity at 20 min/ peak Cortical activity at 20 min/ peak activity : activity :

< 0.30 on MAG3 renogram. < 0.30 on MAG3 renogram.

RELATIVE/SPLIT RELATIVE/SPLIT FUNCTIONFUNCTION

Contribution of each kidney to the Contribution of each kidney to the total functiontotal function

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

ROI: Region of interestROI: Region of interestNormalNormal 50/50 - 56/44 50/50 - 56/44

BorderlineBorderline 57/43 - 59/4157/43 - 59/41

AbnormalAbnormal > 60/40> 60/40 Taylor, SeminNM Apr 99

Relative (split) functionRelative (split) functionROI’sROI’s

Quantitation of Renal Quantitation of Renal Function Function

GFR & ERPF measurementGFR & ERPF measurement Two methods :Two methods : Plasma sample based clearances Plasma sample based clearances : : The amt of activity remaining in blood at The amt of activity remaining in blood at

prefixed times is a measurement of activity not prefixed times is a measurement of activity not yet cleared – indirect measure of activity yet cleared – indirect measure of activity already cleared.already cleared.

More accurate ,but requires determination of More accurate ,but requires determination of pharmaceuticals levels in plasma and some pharmaceuticals levels in plasma and some times in urine.times in urine.

Camera based clearances Camera based clearances : : Counts are obtained from syringe Counts are obtained from syringe

before inj. & subsequently over before inj. & subsequently over kidneys after injection.kidneys after injection.

No blood and urine collection.No blood and urine collection. Sufficiently reliable method.Sufficiently reliable method.

Anatomic(Cortical) ImagingAnatomic(Cortical) Imaging(Tc99m DMSA or GH )(Tc99m DMSA or GH )

Images obtained after 2 to 4 hrs of injectionImages obtained after 2 to 4 hrs of injection Posterior/ right post. Oblique/ left post. Posterior/ right post. Oblique/ left post.

ObliqueOblique

NORMAL FINDINGSNORMAL FINDINGS Smooth contour with Homogeneous Smooth contour with Homogeneous

activityactivity Less uptake in medullaLess uptake in medulla No activity in PCS No activity in PCS

Diuretic (Furosemide) Renal Diuretic (Furosemide) Renal ScanScan

Obstructive uropathyObstructive uropathy (hydronephrosis, (hydronephrosis, hydroureter) may lead to hydroureter) may lead to obstructive obstructive nephropathynephropathy (loss of renal function) (loss of renal function)Indications:Indications:

Evaluate functional significance of hydronephrosisEvaluate functional significance of hydronephrosis Determine need for surgeryDetermine need for surgery

obstructive hydronephrosis - surgical Rxobstructive hydronephrosis - surgical Rx non-obstructive hydronephrosis - medical Rx/ non-obstructive hydronephrosis - medical Rx/

follow upfollow up Monitor effect of therapyMonitor effect of therapy

PRINCIPLEPRINCIPLE

Hydronephrosis - tracer pooling in Hydronephrosis - tracer pooling in dilated renal pelvisdilated renal pelvis

Furesemide induces increased urine flowFuresemide induces increased urine flow If obstructed >>> will not wash outIf obstructed >>> will not wash out If dilated, non-obstructed >>> will wash If dilated, non-obstructed >>> will wash

out out Can quantitate rate of washout (Can quantitate rate of washout (TT1/21/2))

PROTOCOLPROTOCOL

Oral hydration prior to studyOral hydration prior to study NS @ 15ml/kg over 30 min 15 min prior to NS @ 15ml/kg over 30 min 15 min prior to

injection & continued in study @ 200ml/kg/24 injection & continued in study @ 200ml/kg/24 hrhr

Bladder catheterization is required in childrenBladder catheterization is required in children Tc 99m MAG3 – agent of choice in children Tc 99m MAG3 – agent of choice in children

with limited functionwith limited function high target-to-background ratio, good image high target-to-background ratio, good image

quality, and more accurate numerical valuesquality, and more accurate numerical values

PROTOCOLPROTOCOL Pre requisite – residual function to Pre requisite – residual function to

respondrespond Diuretic given Diuretic given ( infants- 1mg/kg, ( infants- 1mg/kg,

children 0.5 mg/kg, 40 mg adults ) children 0.5 mg/kg, 40 mg adults ) 20-30 min 20-30 min after radiotracer injectionafter radiotracer injection

Imaging for 20 – 30 minutes, post Imaging for 20 – 30 minutes, post micturition imagemicturition image

Functional images, renogram Functional images, renogram time/activity curve( before & after ), time/activity curve( before & after ), wash out half time calculated wash out half time calculated

symmetric uptake and good washout symmetric uptake and good washout is by definition not obstructedis by definition not obstructed

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

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

Showing non-obstructive hydronephrosis of the left kidney, The arrow indicating a brisk response to intravenous diuretic.

Scintigraphic evaluation of Hydronephrosis

Scintigraphic evaluation of Hydronephrosis

Showing obstructive hydronephrosis of the right kidney, The arrow indicating a no response to intravenous diuretic.

““F minus 15” F minus 15” Diuretic Diuretic RenogramRenogram

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

Captopril Renal ScanCaptopril Renal Scan (ACEI Renography) (ACEI Renography)

Renovascular Disease Renovascular Disease

Renal artery stenosis (RAS)Renal artery stenosis (RAS)

Ischemic nephropathyIschemic nephropathy

Renovascular hypertension (RVH)Renovascular hypertension (RVH)

RAS RAS RVH RVH

Renin-Angiotensin Renin-Angiotensin SystemSystem

RAS

CaptoprilCaptopril

Angiotensinogen

Angiotensin I

Angiotensin II

Aldosterone Vasoconstriction

HTN

Renin

ACE

Effect of RAS on GFREffect of RAS on GFR

Renovascular Renovascular HypertensionHypertension

PrevalencePrevalence <1% unselected population with HTN<1% unselected population with HTN

Clinical featuresClinical features Abrupt onset HTN in child, adult < 30 or > Abrupt onset HTN in child, adult < 30 or >

60y60y Severe HTN resistant to medical RxSevere HTN resistant to medical Rx Unexplained or post-ACEI impairment in Unexplained or post-ACEI impairment in

ren fctren fct HTN + abdominal bruitsHTN + abdominal bruits

If these present - moderate risk of RVH (20-If these present - moderate risk of RVH (20-30%)30%)

Diagnosis of RASDiagnosis of RAS

Gold standard: angiographyGold standard: angiography Initial non-invasive tests:Initial non-invasive tests:

ACEI renographyACEI renography Duplex sonographyDuplex sonography

Other tests: Other tests: MRA - insensitive for distal / segmental MRA - insensitive for distal / segmental

RASRAS Renal vein renin levelsRenal vein renin levels

Captopril Renal ScanMAG 3Captopril Renal ScanMAG 3

Tc 99m MAG 3 = gold standardTc 99m MAG 3 = gold standard

Stop ACE inhibitors 48 hrs prior and no Stop ACE inhibitors 48 hrs prior and no solid food before 4 hrssolid food before 4 hrs

Before procedure, orally fluid – 10 ml/kgBefore procedure, orally fluid – 10 ml/kg

Hydration continued i.v. 4ml/ minHydration continued i.v. 4ml/ min

Baseline BP & PR recorded→ captopril 50 Baseline BP & PR recorded→ captopril 50 mgmg

Protocol: Protocol: 1 day 1 day vsvs. 2 day test. 2 day test 1 day test: 1 day test: baseline scan (1-2 mCi) baseline scan (1-2 mCi)

followed by followed by post-Capto post-Capto scan (8-10 mCi)scan (8-10 mCi)

2 day test: 2 day test: post-Capto scan, post-Capto scan, only if abnormal >> only if abnormal >>

baseline baseline

Abnormal captopril Abnormal captopril RenographyRenography

Delayed time to maximal activity >11 Delayed time to maximal activity >11 minutes(normal -5min)minutes(normal -5min)

Significant asymmetry of peak activity of Significant asymmetry of peak activity of each kidneyeach kidney

Marked cortical retention of radionuclide Marked cortical retention of radionuclide A marked decrease in the GFR of the A marked decrease in the GFR of the

ipsilateral kidney. ipsilateral kidney. 20-minute counts /peak counts [N <0.3 ], 20-minute counts /peak counts [N <0.3 ],

0.15 change is considered significant.0.15 change is considered significant.

Captopril Renal Captopril Renal ScanMAG 3ScanMAG 3

MAG3 RENOGRAMMAG3 RENOGRAMCAPTOPRIL RENOGRAM CAPTOPRIL RENOGRAM TIME/ACTIVITY CURVETIME/ACTIVITY CURVE

AFTER 48 HOURSAFTER 48 HOURS

MAG3 RENOGRAMMAG3 RENOGRAM CAPTOPRIL RENOGRAM CAPTOPRIL RENOGRAM TIME/ACTIVITY CURVETIME/ACTIVITY CURVE

AORTOGRAMAORTOGRAM

ACEI RenographyACEI Renography

In normal renal function - sens/spec ~ 90%In normal renal function - sens/spec ~ 90% In poor renal function / ischemic nephropathy, In poor renal function / ischemic nephropathy,

ACEI renography often indeterminate ACEI renography often indeterminate >>> do MRA, Duplex US, angiogram>>> do MRA, Duplex US, angiogram

Renal Cortical ScintigraphyRenal Cortical Scintigraphy

Indications Indications

Determine involvement of upper tractDetermine involvement of upper tract

(kidney) in acute UTI (acute (kidney) in acute UTI (acute

pyelonephritis)pyelonephritis)

Detect cortical scarring (chronic Detect cortical scarring (chronic

pyelonephr.)pyelonephr.)

Follow-up post RxFollow-up post Rx

CONTD..CONTD..

gold standard gold standard 99m99mTc DMSATc DMSA The radiotracer is taken up only by The radiotracer is taken up only by

functioning PCT mass functioning PCT mass Pyelonephritis impairs tubular uptake Pyelonephritis impairs tubular uptake

of radiotracer, these areas appear as of radiotracer, these areas appear as unexposed or underexposed unexposed or underexposed

Persisting areas on follow up indicates Persisting areas on follow up indicates irreversible renal damage or scarring.irreversible renal damage or scarring.


Cold Defect Cold Defect Acute or chronic PNAcute or chronic PN CystCyst TumorsTumors InfarctInfarct Trauma (contusion, laceration,hematoma)Trauma (contusion, laceration,hematoma)

Cortical defects are not always d/t Cortical defects are not always d/t infection & allinfection & all

DMSA defects are not necessarily scars.DMSA defects are not necessarily scars.


Congenital Anomalies Congenital Anomalies AgenesisAgenesis EctopyEctopy Fusion Fusion (horseshoe, crossed fused ectopia)(horseshoe, crossed fused ectopia) Polycystic kidneyPolycystic kidney Multicystic dysplastic kidneyMulticystic dysplastic kidney Pseudotumors Pseudotumors (fetal lobulation, (fetal lobulation,

hypertrophic column of Bertin , lobar hypertrophic column of Bertin , lobar nephronia)nephronia)

NORMAL DMSA SCANNORMAL DMSA SCAN

HORSE SHOE KIDNEYHORSE SHOE KIDNEY

Horseshoe kidney with normal function

RENAL AGENESISRENAL AGENESIS

Patient with Recurrent UTI

Tc99m-DMSA renal SPECT scintigraphy Ectopic left kidney with multiple scars

Renal Transplant Evaluation:

Anterior images are obtained.Anterior images are obtained. Normal perfusion study: radioactive Normal perfusion study: radioactive

bolus reaches the renal transplant bolus reaches the renal transplant simultaneously with iliac vessels. simultaneously with iliac vessels.

Max parenchymal phase :3-5 minMax parenchymal phase :3-5 min Bladder activity appears : 4-8 minBladder activity appears : 4-8 min Up to 2 weeks after Tx, prominent Up to 2 weeks after Tx, prominent

visualisation of ureter due to edema visualisation of ureter due to edema at UV anastomotic site.at UV anastomotic site.


Transplant kidney is showing good perfusion, uptake and drainage of radiotracer- Normal Study

Tc99m-DTPA renal dynamic scintigraphy

POST OP 1 WEEKPOST OP 1 WEEK POST OP 2 WEEKSPOST OP 2 WEEKS

Acute Tubular Necrosis: Acute Tubular Necrosis: Preserved or mildly reduced renal perfusion but Preserved or mildly reduced renal perfusion but

diminished renal function and progressive diminished renal function and progressive cortical retention of tubular agents.cortical retention of tubular agents.

Acute Rejection :Acute Rejection :

Poor perfusion than function in early stagePoor perfusion than function in early stage

Renogram demonstrates a diminished nephrogram phase and delayed Renogram demonstrates a diminished nephrogram phase and delayed appearance of bladder activity.appearance of bladder activity.



Acute Rejection Acute Tubular Necrosis

Transplant kidney is showing poor perfusion, uptake and drainage of radiotracer- Chronic Rejection



Cyclosporin nephrotoxicity :Cyclosporin nephrotoxicity : Scintigraphic appearance similar to Scintigraphic appearance similar to

ATN, with relative good transplant ATN, with relative good transplant perfusion and poor tubular function.perfusion and poor tubular function.

Compared to ATN ,it occurs several Compared to ATN ,it occurs several weeks after transplatation.weeks after transplatation.

Renal transplants scintigraphy Renal transplants scintigraphy Surgical complicationsSurgical complications

Urinary leak-Urinary leak-Initial photopenic defect with Initial photopenic defect with progressive accumulation of radiotracer progressive accumulation of radiotracer

Hematoma/ Abscess-Hematoma/ Abscess- Initial photopenic Initial photopenic defect not changing with time.defect not changing with time.

Lymphocele-Lymphocele- Initial photopenic defect- equal Initial photopenic defect- equal to background activity in delayed images.to background activity in delayed images.

Ureteral obstructionUreteral obstruction

Arterial stenosis and hypertensionArterial stenosis and hypertension


10th Post operative day of renal transplant decreased urine output and pelvic collection

Urinary leak


2nd Post operative day of renal transplant Hematoma / abscess


7th Post operative day of renal transplant c/o Increased serum creatinine and pelvic collection

Lymphocele

Radionuclide CystogramRadionuclide Cystogram

INDICATIONSINDICATIONS Assess effect of Assess effect of

therapy / surgerytherapy / surgery Screening of Screening of

siblings of reflux siblings of reflux ptspts

Evaluation of Evaluation of children with children with recurrent UTIrecurrent UTI(30-50% have VUR)(30-50% have VUR)

PROsPROs More sensitiveMore sensitive 100 times less 100 times less

radiationradiationCONsCONs Inferior anatomic Inferior anatomic

deleniationdeleniation

Radionuclide CystogramRadionuclide Cystogram

RefrencesRefrences

Oxford text book of clnilcal Oxford text book of clnilcal nephrology-3nephrology-3rdrd ed. ed.

Essentials of Nuclear Medicine Essentials of Nuclear Medicine Imaging – Mettler & GuiberteauImaging – Mettler & Guiberteau

Brenner and Rector’s The kidney– 9Brenner and Rector’s The kidney– 9thth ed.ed.

www.google.comwww.google.com

Nuclear imaging in kidney disease

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