nuclear medicine for urogenital and GI disease

Question 1

What ligand is excreted specifically by glomerular filtration

and by tubular secretion

Answer 1

DTPA is only by filtration

MAG-3 or EC Ethylenedicysteine, only by tubular secretion.

Question 2

What measures are performed when analysing kidnesy by nuclear medicine

Answer 2

The relative excretion by each kidney,

The relative excretion in the early phase by filtration, and in the second phase by predominantly the secretion.

Is there an obstruction or is the kidney not functioning.

Question 3

Effect of ACE-inhibitors on a kidney with a stenotic renal artery

Answer 3

Will have not be able to increase their blood flow in response to the inhibitor, but the efferent artery vessel will still dilate, and it will have even further decreased funciton.

Question 4

DMSA Scan

Answer 4

(DMSA) demonstrates a similar reduction in renal perfusion and function, which appears as one or more patchy scintigraphy defects in the outline of the kidneys,

Regions of reduced activity on a long static scan
indicate pyelonephritis or scars

Question 5

Radionuclide cystography

Answer 5

To evaluate vesicoureteral reflux

Isotope delivered via catheter into the bladder, then imaged during and after urination.

Question 6

Imaging the liver and biliary sysem

Answer 6

Colloid liver-spleen scintigraphy,
A solution containing Tc labeled molecules that are taken up by reticuloendothelial cells and Kuppfer cells.

lighting up the spleen and liver

the purpose is to scan for focal nodular hyperplasia or regenerative nodules associated with Cirrhosis.
Both appear as well-circumscribed hypodensities/defects.

Question 7

Cholescintigraphy

Answer 7

Tc labeled HIDA, or BrIDA tracers, competes with bilirubin.
Used with SPECT to evaluate liver function and gall bladder emptying.

and to locate focal nodular hyperplasia.

Question 8

Focal nodular hyperplasia

Answer 8

In colloid scintigraphy,
These nodules will be uptake excessive tracer, but lack normal biliary tracts to secrete it, trapping the tracer which is the slowly redispersed back to the rest of the liver and secreted.

This can in some cases be mimiced by very well differentiated HCC.

Question 9

Three phase blood pool scntigraphy

Answer 9

For hemangiomas, and for localizing GI bleeding, especially for meckels diverticula bleeding in infants.

RBCs are labeled with Tc-Pertechnetate.

• Cavernous hemangioma have decreased activity in the perfusion phase
• In the early blood content phase, this persists, as it gradually fills up the cavernous spaces.
• In late phase, there is higher signal from the cavernous hemangioma as it slowly empties.

Question 10

IBD scintigraphy

Answer 10

Tc labeled White blood cells are used, to locate inflammatory lesions.

Question 11

GI motility can be done by scintigraphy with labeled food or liquid that is ingested, why do it?

Answer 11

In infnants or children because it is very non-invasive and has a low radiation burden.