RENAL RADIONUCLIDE STUDIES Kateřina Michalová

Klinika nukleární medicíny a endokrinologie UK 2. LF a FN Motol

RENALRADIONUCLIDE STUDIES

Kateřina Michalová


Radionuclide diagnostics methods

Noninvasive

Are primarily physiologicFunctional

Does not provide the same anatomic details as morphologic method (X-ray,US,CT,MRI)

Kupka K .a kol: Nukleární medicína, 2002


Nuclear renal imagingincludes these methods

1. Renal dynamic scintigraphy

2. Renal cortical scintigraphy

3. Radionuclide Cystography


Dynamic renal scintigraphy

Is a functional examinationProviding information about intrarenal kinetics

Of the i.v. applied radiopharmaceuticalAnd of its transport via the efferent urinary tracts

The specific information obtained depends of radiopharmaceutic injected.


Dynamic renal scintigraphy

There are two kinds of

Radiopharmaceticals: a) Tubular agents 99mTc-MAG3 Mercapto-acetyltriglycin 131I -,123I-Ortoiodhippurate b) Glomerular filtration rate agens 99mTc-DTPA Diethylentriamine pentaacetic acid


RadiopharmaceuticalsMechanisms of excretion

you can see in the picture

Glomerular filtration• 99mTc DTPA• Tubular secretion• 99mTc MAG3• 131I, 123I – OIH

Tubular fixation• 99mTc DMSA• 99mTc glucoheptonate


Radiopharmaceticals

99mTc-DTPA – Diethylentriamine pentaacetic acid

belongs to the group of chelate compounds is excreted from kidneys through glomerular filtration with a half-life of 70 minutes it is the most suitable substance for measuring glomerular filtration (GFR) and good imaging of renal parenchyma

Vižďa J. a kol : Atlas of Renal Scintigraphy, 2002.


Radiopharmaceticals

99mTc-MAG3 - Mercapto-acetyltriglycine -is one of the newly developed radiopharmaceuticals-is rapidly excreted by the kidneys via active tubular secretion and minor part via glomerular filtration -organic anions (which include MAG3) have a carboxyl group which specifically binds to the receptors of tubular cells mediating the active transport of MAG3 into the cells of the proximal tubulus-with normaI renal function 70% of the administered activity of the radiopharmaceutical (RP) is excreted within 30 minutes after the application


Dynamic renal study

Radiopharmaceutical 99mTc - MAG3

Patient Preparation adequately hydration prior to the examination it is recommended to drink 100 ml of liquids per 10 kg of the body weight 30 min prior the examination empty bladder p.are requested to void completely prior to the study


Dynamic renal study Image Acquisition p.is usually examined in the supine position sometimes in sitting position detector of the gamma camera is in the posterior projection field of view includes the area of kidneys, ureters and the area of the bladder

data recording starts immediatelly before the intravenous injection

as serial 15 sec images for 20 min radionuclide angiography 1 s frames are recorded for a period 1 minut after the administration of the RF can be used in examination of kidney grafts



Evaluation

• visuel

• parenchymal phase

• position

• size

• shape

• distribution RF

• excretory phase

• dilatation of the collecting system


Summed image of all frames during the clearance phase

ROI (regions of interest) are drawnRenal ROI – arround the kidneyBackground ROI–below the kidney

Computer processing of the study


Renogram curves

Computer processing of the study

Parameters of the curves

Tmax = time ofachieving the peakof the curve

T1/2 = intervalbetween the time ofachieving the peakof the curveand the decreaseto 50% of the peaklevel

Time activity curves derived from renal ROI


Computer processing of the study quantitation of the individual renal functiondifferential renal function DRFcalculated within 1 to 3 minutes post injection of RPphysiological range is 45%-55%


Normal renogram curve

A

II. III.

I.

I. Vascular phase II. Secretory

III. Excretory

čas


A

čas

normal

obstructed pattern

impaired renal functionparenchymal lesion pattern

renal failure patternwithout measurable kidney uptake

renal failure patern

Patterns of renographic curves


Dynamic renal study

Indications All uropaties, which require evaluation of individual renal

function at diagnosis and during the different phases of surgical or conservative treatment

and evaluation of the drainage function

Examples include dilatation of the cause (e.g.Pelvi-Ureteric and Vesico-Ureteric dilatation), bladder dysfunction, complicated duplex kidney, post trauma, asymetrical renal function and reflux nefropathy.


Diuretic Renography The purpose of diuretic renography is to differentiate a true obstruction from a dilated non obstructed system (stasis) by serial imaging after intravenous administration of furosemide (Lasix)) 1) Standart renogram When dilatation of the collecting system exists, standart renogram should be complemented by a diuretic renogram 2) Diuretic renogram – additional 15-20 min acquisition, using the same technique as above Furosemid - 1mg/kg with a maximum dose 20mg (40 mg dle *SNM) *Society of Nuclear Medicine Procedure Guadeline for Diuretic Renography in Children


A

čas

non obstruction dilatation (hypotonie stasis)rapid washout fromthe collecting system

obstruction no response to a diureticno washout of RP from the collecting system

Furosemid i.v.


Diuretic renography Indications differentiation obstructive from non obstructive causes of hydronephrosis and hydroureteronephrosis

Ureteropelvic or ureterovesical obstruction Prenatal ultrasound diagnosis of hydronephrosis Post-surgical evaluation of the previously obstructed system Distension of pelvicalyceal system as an etiology of back pain


no obstruction

non obstruction dilatation (hypotonie stasis)rapid washout fromthe collecting system

furosemidverticalposition

Left kidney -enlarged-dilated collecting systemwith pronouncedretention of urine-response tothe diuretic israpid

Right kidneynormal shapecollecting systemwith pronouncedretentin of urine-response to the diuretic is rapid


obstructionpoor response to a diureticno washout of RP from the collecting system

Left kidney -enlarged-dilated collecting systemwith pronouncedretention of urine-poor response tothe diuretic

Right kidneywashoutof urine is freeby nefrostomy

furosemidverticalposition


obstructionno response to a diuretic

Right kidney -enlargedhypofunctionalimpresionof dilatated collecting isseen, but no good fiilingno response to a diuretic

Left kidney normal

severe obstructionno response to a diureticno washout of RP from the collecting system


Renal Cortical Scintigraphy

Static imaging of the kidney

Radiofarmaceutical : 99mTc-DMSA Dimercaptosuccinic acid

Following iv injection is taken up into the renal cortex in the proximal convoluted tubule.The main site of accumulation are the micro somes of the cells of

proximal tubules.

It is cleared slowly , urine exrection is low.


Renal cortical scintigraphy

Patient Preparation no

Image Acquisition static high resolution images of kidneys (ANT, POST, RPO, LPO projection) SPECT in the supine position

2,5 h after injection DMSA cleared slowly (high radiation dose versus DRS !!!)



Common Indications1. Acute pyelonephritis2. Renal scarring3. Relativ functioning renal mass 4. Solitary or ectopic renal tissue (e.g.,pelvic kidney)4. Horseshoe and pseudohorseshoe kidneys5. Allergie to iodinated contrast agents

Society of Nuclear Medicine Procedure Guideline for Renal Cortical Scintigraphy in Children



- is used for detection of cortical defects of acute pyelonephritis (loss of function) and scarring related to chronic pyelonephritis.

- is able to detect twice as many defects as ultrasound 4 times as many defects as intravenous urography- computed tomography has sensitivity and specificity similar but adds to the risk of contrast reaction and has a higher radiationexposure- magnetic resonance imaging is promising but expensive nonionizing method of vizualizing pyelonephritis

Society of Nuclear Medicine Procedure Guideline for Renal Cortical Scintigraphy in Children


ANT POST

RPO LPO

Normal renal scan


Evaluation- number of kidneys- position- size- shape- the size, number and location of areas cortical loss- split renal function

Note!

Cortical „cold“ defect may be due to

different etiology :

tumor, abscess, cysts ….

alrealdy is necesarry to compare with US


Evaluation of split renal function- for determination of percent differential function regions of interest of each kidney and background area are outlined on the computerized posterior and anterior images.

- split renal function normally varies from 45%-55%


Acute pyelonephritis(multifocal)

-more foci of reduced accumulation of the RP

-diffuse damage to the parenchyma


Scarring

2-years old girl after repeated infection of uropoetic system

ANT POST

RPO LPO

characterized as :-wedshaped defects-with thinningor flattening of the cortex-irregularmargins-loss of volumeof the kidney


ANT POST

dystopia

Anomalies of position and number


Direct Radionuclide CystographyMicturating cystography (MCG)

-The examination is performed in the same way as X-ray MCG-Requires catheterization of the bladder and instilation of radionuclide and fluid for maximal physiological distension of the bladder, -Allowing imaging (dynamic scintigraphy) during filling, voiding, and after voiding. Radiopharmaceutical 99mTc- MAG3 Patient preparation no Time of examination 1 h


Direct Radionuclide Cystography

Common Indication Screening and therapy monitoring vesicoureteral reflux Diagnostic of familiar reflux

Evaluation of vesicoureteral reflux after medical management Assesment of resuls of antireflux surgery

Comparing with conventional radiographic technique (X-ray MCG)• less gonadal radiation (100-200x lower than X-ray MCG)

• higher sensitivity for detection of vesicoureteral reflux• does not provide the same anatomic details as X-ray MCG

Society of Nuclear Medicine Procedure Guideline for Radionuclide Cystography in Children


Direct Radionuclide Cystography

Vezikoureteral reflux

Interpretation criteria

Grade

I. with activity limited to the ureter II. with activity reaching the collecting system with none or minimal activity in ureter III. with a dilatation of the collecting system and dilated ureter

Society of Nuclear Medicine Procedure Guideline for Radionuclide Cystography in Children


Visual evaluationNormal patternno activity is recorded in the ureters


VUR grade I (into ureter)


VUR grade II (into collecting system of the kidney)


VUR grade III (into collecting system of the kidney with a dilatation)

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RENAL RADIONUCLIDE STUDIES Kateřina Michalová

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