Paediatric Nuclear Medicine - Higher Education AP diameter of the pelvis on ultrasound and DRF...

Anita Brink

Nephro –urology: • DMSA Scans

• MAG3 renograms

• Indirect Cystograms

Gastro oesophageal studies “Milkscans”

Oncology topics

The “missing” kidney: • Multicystic dysplastic kidney

• Agenesis

• Ectopic kidneys

• Fused kidney

The “scarred” kidney: • Hypertension

• Urinary tract infections

Probable multicystic dysplastic kidney:

Ultrasound findings: • No or thin cortex

• No communication between cysts

• Ureter not seen

• Bladder normal

DMSA done when baby 6 weeks.

Multicystic dysplastic kidney:

Acute infection- within 10 to 14 days after

onset of symptoms.

To assess for permanent defects – wait at

least 6 months after infection.

The patient has hydro-nephrosis, MAG3

is the agent of choice.

Pelvic kidney/s = MAG3 is better in

theses cases

The new born baby you are seeing had

an antenatal ultrasound that showed

hydronephrosis.

Where do you go from here?

Prenatal hydronephrosis is found in

approximately 0.25% of pregnancies(1).

There is spontaneous resolution in:

50% of cases with mild

15% with moderate and

0% with severe hydronephrosis(2).

1.Helin I, Person P.H. Prenatal diagnosis of urinary tract abnormalities by

ultrasound. Pediatrics, 78:879, 1986.

2.Feldman, D.M. et al: Evaluation and follow-up of fetal hydronephrosis.

J Ultrasound Med, 20: 1065,2001.

A post natal ultrasound is performed to confirm the antenatal findings.

This should not be performed in the first five

days of life unless the antenatal ultrasound is grossly abnormal.

Once hydronephrosis is conformed on

postnatal ultrasound a MAG3 study is

done in all cases.

Timing of MAG3 depends on: 1. The size of the renal pelvis.

2. Thickness of cortex.

3. Renal pelvis intra/ extra renal.

NOT done in the first week of life.

Ideally after 6/52.

Preferably after 3/52.

Only done between 7 and 21 days if

there is severe hydronephrosis – can this

kidney be salvaged?

Differential renal function (DRF) is the

most important information obtained

from the renogram.

The AP diameter of the pelvis on

ultrasound and DRF determine the

treatment and follow-up investigations of

the patient.

1. Infections/Complications.

2. Fall in differential renal function.

3. Increasing AP pelvis (relative

indication).

DRF 50/50%.

AP pelvis Calyceal

dilatation

Baseline

MAG3 at

Follow-up

MAG3 at

< 20 mm Seldom

marked

3/12 9/12

20 – 30mm Not marked 9/52 6/12 - 9/12

20 – 30mm Marked 6/52 3/12 – 6/12

30 - 40mm Not marked 6/52 6/52 – 3/12

30 – 40mm Marked 3/52 3/52 - 6/52

> 40 mm uncommon at 50/50% DRF

Ultrasound studies are booked between

two MAG3 studies. If the ultrasound

results are of concern the MAG3 study is

moved forward.

DRF 30/70% follow-up MAG3 and

ultrasound studies are done earlier

because the one kidney is already

compromised

As with DRF 50/50% the MAG3 renogram

is moved forward if the ultrasound results

are of concern .

DRF 15/85% - 20/80%.

The follow-up MAG3 is done 2/52 - 4/52

after initial study.

Consider doing a MCUG here.

These patients are candidates for nephrostomy

early surgery

early stent.

DRF of affected kidney < 10%.

Probably not salvageable, surgery often

technically very difficult.

Probably not worth saving.

Do MCUG if the

ureter is visible or

bladder abnormal

Follow-up depends on the result of each study.

E.g. no change on the 3 month follow-up do the repeat MAG3 renogram in 6 months time, with an intervening ultrasound.

Children with stable total renal function and DRF for 3 years very unlikely to need intervention.

Follow-up is determined by:

1. Renal function, serum creatinine or GFR

2. AP diameter.

3. Cortical thickness.

4. Communication between calyces and

pelvis, pelvis and ureter and also ureter

and bladder.

5. Bladder morphology.

Investigations are done earlier and more frequent.

The timing of the investigations depends mostly on the

serum creatinine/ GFR and AP pelvis.

If the bladder morphology is deranged

MCUG is done in the neonatal period.

Please note that the absence or presence

of a Lasix response is not used to make

any treatment decisions.

90% of 474 neonates allocated to

watchful waiting were not operated on.

Only 10 % were subjected to delayed

pyeloplasty, mostly because of an

increase in pelvic size and/or decreasing

renal function.(4)

Josephson S. Antenatal detected, unilateral dilatation of the renal pelvis: a

critical review. 1 post natal non-operative treatment 20 years on is it safe?

Scand J Urol Nephrol 2002;36: 243-250.

The child needs to be potty trained!!

A basic renogram is done.

In most children the bladder will be full

of activity, and the kidneys would have

cleared 40 minutes after injecting the

tracer.

We take 2- 5 ml of the child’s own milk and label it with 99m Tc tin colloid.

The child drinks this in front of the camera. Preferably on mommy’s lap.

The child then drinks the rest of their normal feed.

The child is burped. The reflux and aspiration search is then

done for 35 min. One hour brake, no eating no drinking. The one last 5 minute image for aspiration

check and gastric emptying calculation.

Two 5 minute static images, one after the

reflux search and another two hours after

the feed.

Normal Glucose:

Plasma

Glucose Glucose-6-PO4

Glucose

Glycolysis

GLUT-1

Hexokinase

G-6-P

Tumor cell:

FDG

FDG FDG-6-PO4

Glycolysis

GLUT-1

Hexokinase

G-6-P

3 03 2011 13 01 2011