Department Of Nuclear Medicine, First Affiliated Hospital Of Zhengzhou University

Urinary System Nuclear Medicine Department of Nuclear Medicine, First Affiliated Hospital of Zhengzhou University 郑州大学第一附属医院核医学科 程 兵 Cheng bing [email protected] Tel: 65035772

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Urinar y System Nuclear Medicine

Part 1

Renogram

Key point ❚ The principle of the

Very important

I-OIH

131

renogram. ❚ How many kinds of abnormal renogram patterns? And their names? 3

Simplified Diagram of nephron

4

nephron sketch image

Principle ❚

Very important

A renogram is recording of the timeactivity curve obtained from the renal areas following the intravenous injection of a suitable radiopharmaceutical.

❚

Two alternatively detcetors attached to a ratemeter and recorder are posited to record radioactive information from each kidney. 7

❚

The compound of choice(

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I-o-iodo-Hippuran

,OIH)is injected intravenously. ❚ About 90% of the Hippuran injected can be uptaken and plasma )

excreted (removed from

to urine by the the renal proximal

convoluted

tubule cells at each

passage through the kidney. 8

❚

The normal kidney accumulates Hippuran quite quickly.It traverses the tubular cells in a few seconds and travels along the nephrons to the renal pelvis In 2-4 min. Hippuran normally drains from the renal pelvis via the ureter almost immediately. At any given moment,activity recorded over a kidney is the sum of renal and extra-renal activity within the field of view. 9

❚

During these proceeding the recorder can record the variety of radioactivity and draws a time activity curve (TAC) on plotting paper outside of the body of the patient. The TAC is the renogram what we name. 10

❚ This test has the distinct advantage of giving an overall index of renal function and a pointer to the relative function of each kidney. 11

et a ni dr o

x-coordinate

Abscissa

The Advantage of the Test ❚

The renogram can give an overall index of renal function and a pointer to the relative function of each kidney . ( the differential function between the two kidneys) ❚ The test is timesaving, It takes only about 20 -30min ; ( we can quickly get the results and make our diagnosis) ❚ It is very easy to test and usually no special preparation is needed; 13

❚

It

is

a

outpatient small

non-impairment procedure .

radiation

exposure

clinicians to use

the test

method

and

a

Zero mortality and have

encouraged

to monitor serially

the effect of treatment and surgery. ❚

It is very with

other

cheap and cost much less compared methods

,e.g

X

ray

intravenous

pyelography (IVP).

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Pharmaceuticals and Methods ❚

I-Hippuran (Orthoiodohippurate)is given intravenously to the patient in a dose of 550μCi at a bolus state.

❚

In normal adults ,it is satisfactory to place the probe 6-6.5cm to each side of the midline. parallel to each other and centered mid-way between twelfth rib and iliac crest. An unusually mobile kidney may be too low to be included fully.giving a low,rounded curve.

131

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❚

The test may be done with the patient lying down or sitting up . But ureteric drainage is better observed erect. If the third phase falls ,the patient should walk slowly for 1-2 min,and then resume his position to ensure that the impairment is not postural.

❚

If it is difficult to localizing the kidneys the ultrasound or CT examine is necessary prior to the test. 16

Indications 1.Detecting relative function of each kidneys; 2. Obstruction of the urinary tract ; 3.Any parenchymal or vascular renal disease; 4.Ureteric reflux; 5.Inspecting renal transplantation and monitor of rejection in kidney graft; 6.Assessment of renal function; 7.Investigation of kidney function in patients allergic to contrast media with IVP.

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Normal renogram

Left : Sketch Map

Right : Real renogram

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a segment: the period of tracer appearance b segment: the period of tracer extraction c segment: the period of tracer elimination

❚ Tracer appearance describes the period of blood flow beneath the detector. ❚ tracer extraction is proportional to renal plasma flow or glomerular filtration rate according to used tracer . ❚ tracer elimination is related to drainage of the urine from the renal .

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❚ The kidney is limited in the number of ways it can handle a tracer in response to disease; it may accumulate less of the tracer, accumulate it at a slower rate, or eliminate it at a slower rate. Tracer kinetics can be altered by disease as well as by the level of hydration or dehydration. Proper interpretation of the renogram curve requires the clinician to understand what the curve implies in terms of renal function and then to relate that functional information to potential disease processes.

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❚ Nowadays

mathematical

function

called

deconvolution is also used for renogram curve evaluation. It can better detect renal artery stenosis and distinguish between obstruction and nonobstructed pelvic dilation and detect transplant rejection.

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Abnormal renogram Patterns Rapidly ascending Curve

1

High level extending Curve

2 Parabola

Ladder Pattern descenging Curve

3 low level extending curve

4 Low Level descending Curve

5

6 Small renogram

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Rapidly Ascending Curve

High Level Extending Curve

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Rapidly Ascending Curve ❚

If double kidneys represent the

same

type of the Rapidly ascending curve

the

patient may be have acute renal failure and it is within the phase of uropenia, or with the secondary affection of the lower urethremphraxis . ❚

A single side kidney has the type reveal that there is a obstruction

on the upper

ureter. 27

High Level Extending Curve ❚

High

level extending

curve

always

being found on the patient with a upper ureter obstruction accompanied by hydronephrosis. ❚ This curve clarifies that the time of obstruction is short and the renal function is good right now.But urine can not drain out of the kidneys. 28

❚

Urinary tract obstruction is a very common problem, which if untreated may lead to progressive renal damage and renal failure. Early and accurate diagnosis is therefore of paramount importance. The obstruction may be acute or chronic, persistent or intermittent. hence, the assessment of renal function and its changes with time are important in selecting the therapeutic intervention. 29

Parabola

low level extending curve

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Parabola ❚

Parabola type frequently being found on the patient with renal ischemia, renal dysfunction, upper ureter accompanied

by

slight or

obstruction intergrade

hydronephrosis. The pre-renal, renal and post renal factor can all influence the type of the curve.

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Low Level Descending Curve

Ladder Pattern descenging Curve

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❚

Low level extending curve

❚

The curve reveals that the renal function was severely damaged by any cause , and often found on the patients with uraemia.

❚ ❚

Low level descending curve If the curve appears that the function of the kidney vanished.

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Ladder Type descending Curve ❚

Ladder type descending curve itself in the nervous patients

presents

and

the

patients with urinary system inflammation, pain and uropenia due to ureter of

these

patients

the

upper

contracts or

spreads convulsively .

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Small renogram

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❚

Small renogram

is defined by the

ratio : the counts of segment b segment b

right

left

minus

to the average counts of

segment b >30%,and the shape of the small renogram is normal. ❚

The kidney of Small renogram side must have a renal artery stenosis , but

you must

excludes postural factor effect. 37

Specificity ❚

Patterns and

often

of a

the strength

abnormality definite of

are

usually nonspecific

diagnosis cannot

be

the renogram alone. The

made on patient

with a certain disease may reveal several abnormal patterns and a certain abnormal patterns may represent in many diseases. ❚ so you must tightly combine the case history to make a correct diagnosis.

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❚

However the

test may be specific in such

conditions as ureteric obstruction or reflux. It also may be relatively following

some

conditions

urinary

specific in

such as

renal

transplantation. In such cases, although the pattern may be not specific,the changes with a return to normality may be most informative.

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postural factor effect the curve shape

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To be continued…

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