Curs Engleza Renal Scintigraphy Final

8/13/2019 Curs Engleza Renal Scintigraphy Final

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RENAL SCINTIGRAPHY


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Definition

Administration of small amounts of

radioactive substances, called

radiotracers, into the body and then

imaging the kidneys and bladder with adetector- gammacamera.

The images obtained can help in the

diagnosisand treatmentof certainkidney diseases.


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Purpose

It reveals size, position, shape and

function of the kidneys


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Precautions

pregnancy

breastfeeding


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Method Description radiopharmaceuticals.

emit radioactive signals, gamma rays, which can

be collected and counted by a special device,

called gamma camera.

The images of the kidney that the camera

produces are called renal scans.


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Preparation

No preparation is necessary for a kidney

nuclear medicine scan.

to study renal artery stenosis, the patient

must not take angiotensin converting enzyme

inhibitors one week before the scan

drinking fluids


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Risks

Nuclear medicine procedures are very

safe.


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Advantages of renal scintigraphy

include:

minimal radiation exposure

non-invasive easily reproduced

no adverse effects reported


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The most commonly performed

investigations are:

dynamic renal imaging(renography) -

for functionalinformation static renal imaging-

for morphologicalinformation


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Radionuclides

For dinamic study Tc-99m DTPA : the measurement of clearance

corresponds to the glomerular filtration rate- GFR

Tc-99m MAG3 : the measurement of clearance

evaluates the effective renal plasma flow - ERPFFor static study

Tc-99m DMSA : the capacity of renal tubuly totake up those molecules; affords a kidney scanand an evaluation of renal function


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Major indications include:

obstructive uropathy - before and after

surgery

renovascular hypertension - before andafter angioplasty

acute renal failure after treatment

vesicoureteral reflux in children kidney transplant


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STATIC RENAL SCINTIGRAPHY provides morphologicalinformation on each

kidney. TC 99m DMSA: fixed in the proximal renal tubular

cells.

DMSA imaging enables assessment of:

size and position of the kidneys

differential function- expressed as a percentage of the total

function. The upper limit of normal is 5% either side of 50%.

A kidney functioning at 15% of more is still useful; one

whose function is less than 7% is not.

parenchymal defects- scars, cysts, tumors, ischemic areasin renal hypertension

morphological abnormalitiessuch as duplex and horseshoe

kidney


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Figura 1. Scintigrama renal normal Figura 2. Scintigram renal cu Tc99mGH -

rinichi stng mut scintigrafic

Figura 3.Scintigram renal cu Tc99m DMSA - polichistoz renal


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RENOGRAM

The production and excretion of urine is a dynamic

physiological process which can be easily assessed byperforming a Dynamic Renogram study.

This involves taking serial images of the urinary systemfor 25 minutes.

This test is extremely useful in evaluating:

the gross anatomical architecture of the kidneys,

their relative function,

individual GFR and the pattern of urine excretion.

The observations can be displayed in a movie like fashion

or "cine mode" which is useful in identifying organicobstructions to the urine outflow system.

Procedure: Good oral hydration is essential. There is noneed for overnight fasting. Patients need to lie down onthe camera for a period of 25 minutes after an IV injection


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Segments of renogram;

OAvascular phase;

AB- parenchimal uptake phase (evaluation of tubular secretion);

BCDexcretion phase.

Criteria for interpretation: - Renal activity to Peak (RAP)

- Time to peaknormal 3-5 min

- Renal residual activity (RA)less 50%

- T1/2 of peaknormal 16-20 min

Elementary semiology:

Increased transit time: delayed Peak, increased RSA

Impaired secretion: decreased renal activity at peak,

decreased maximal activity

Obstructive pattern: increased residual activity


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16Figura 7. Diverse aspecte ale curbelor nefrografice


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VESICO-URETERIC REFLUX

SCINTIGRAPHY(VUR)

Is indicated in the diagnosis of reflux

vesico-ureteral.

Dinamic renal scan Tc 99m DTPA:

evacuation segment with irregularities;

Static scan by using the cortical imaging

agent Tc 99m DMSA - show diffusebilateral renal scarring;

Mictional nephrography: returning the RF.

back to the kidney .


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Figura 11.Nefroscintigrama micional (reapariia radiotrasorului n

sistemul pielo-ureteral, n timpul evacurii vezicii urinare)


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CAPTOPRIL RENAL

SCINTIGRAPHY (1)

This test is used to evaluate presence of renal artery

stenosis and its physiological sig-nificance, which is one of

the important etio-logical factors in young hypertensives.

The test consists of a Baseline and Post captopril study; Adequate oral hydration;

No antihypertensives based on angiotensin converting

enzyme inhibitors (ACE), one week before the scan;

The sensitivity and specificity of this test is 85% and 80%

respectively.


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CAPTOPRIL RENAL

SCINTIGRAPHY (2) Renal scintigraphy after ACE inhibition

demonstrates a decrease in glomerular filtration in

the presence of a physiologically significant renal

artery stenosis. Renal scintigraphy may be performed using

radiolabeled agents that are excreted primarily by

glomerular filtration (e.g., technetium 99m

diethylenetriamine pentaacetic acid - 99mTc-DTPA) or tubular secretion (orthoiodohippurate-

131 - IOH, or 99mTc-mercapto-acetyltriglycine -

99mTc - MAG.3).


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CAPTOPRIL RENAL

SCINTIGRAPHY (3)

Renal function in an ischemic kidney is abruptly reducedafter one dose of an ACE in-hibitor.

With 99mTc-DTPA, the postcaptopril study demonstratesa marked reduction in uptake of DTPA on the affectedside.

Tubular agents like 99mTc-Mag.3 on the other hand,demonstate progressive accumulation in the affectedkidney during the course of the study.

Reduced glomerular filtration rate causes slow transit oftubular fluid through the tubules, which leads toretention of radio-tracing agent in the tubules.


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Figura 15.Stadializarea nefrogramei n HTA renovascular


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Figura 16.Nefroscintigrama

n HTA renovascular (n

condiii bazale i la captopril)


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Transplant Renogram

evaluation of kidney donors andrecipients.

differentiating Acute Tubular Necrosis

(ATN) from Graft Rejections.

hyperacu te or acute reject ion :

Reduced perfusion while function is

relatively maintained.


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Radionuclide Evaluation of Renal

Function

Estimation of glomerular filtration rate (GFR),

Effective Renal Plasma Flow (ERPF)

Tubular Extraction Rate (TER)


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Curs Engleza Renal Scintigraphy Final