description of the IV and oral contrast used in the CT ( diagnostic imaging )

1. Presented by DR Laith
fadhel
MBchB , P.G.C.R
Contrast media used
with CT

2. Contrast media used with CT
Presented by DR Laith fadhel

3. Information About Intravenous and
Oral Contrast Used in CT
• During many CT examinations, patients may be asked to
take a special contrast agent (orally, rectally or via
injection). Intravenous, oral , rectal and intra articular CT
contrast are pharmaceutical agents (liquids) and are
sometimes referred to as "dye".
• CT contrast is used to make specific organs, blood vessels
and/or tissue types "stand out" with more image contrast
to better show the presence of disease or injury. Thus CT
contrast highlights specific areas of the resultant CT image
or "dyes" it.
• In 1923 1st report of opacification of urinary tract after IV
injection of Sodium iodide solution as treatment of syphilis
by Osborne

4. Types of contrast
There are four types of contrast agent used in CT
1. The type that is given via intravenous injection
2. The type that is given orally
3. The type that is given rectally
4. A much less common type of contrast used in CT
as intra articular ( arthrography ) or inhaled as a
gas and used for special lung and brain imaging.
This technique (called Xenon CT) is only available
at a small number of locations throughout the
world and is only performed for rare cases.

5. How does CT Contrast Work?
Iodide ( intravenous , other )
•
Once the iodine contrast has been
injected into the blood stream, it
circulates through the heart and
passes into the arteries, through
the body's capillaries and then into
the veins and back to the heart. As
CT images are being acquired, the
CT's x-ray beam is attenuated
(weakened) as they pass through
the blood vessels and organs flush
with the contrast. This causes the
blood vessels and organs filled with
the contrast to "enhance" and show
up as white areas on the x-ray or CT
images. The kidneys and liver
eliminate the contrast from the
blood.
Barium sulphate , Gastrografin (oral )
•
Barium and Gastrografin are made
up of substances which weaken
(attenuate) x-rays. The oral contrast
is swallowed and travels into the
stomach and then into
gastrointestinal tract. During the CT
exam which follows, the CT x-ray
beam is attenuated (weakened) as
it passes through the organs
containing the contrast, for
example, the large intestine. The
organs filled with the contrast are
then "enhanced" and appear as
highlighted white areas on the CT
images.

6. Iodide compound contrast
Its mainly classify according to the
osmolarity , ionic or none ionic
The osmolarity of blood about { 290
moSml/kg
• Ionic – HOCM
1- Diatrizole ( urograffin hypaque ) 1500
moSml/kg
2- Metrizoate ( Isopaque )
3- Iothalamate ( Conray )
1500
1500
1- Ioxaglate ( hexabrix )
490
1- HOCM (high osmolar contrast media ) • Ionic -- LOCM
1200-2000 moSml/kg
2- LOCM ( low osmolar contrast media ) • None Ionic – LOCM
350-500 moSml/kg
3- IOCM ( Iso osmolar contrast media )
300 moSml/kg
Note / Iso and Low osmolar are safer 5-10
than HOCM , and well tolerate
1- Iopamidole ( Niopam , Isovue )
2- Iohexol ( Ominpaque )
3- Iomeprol ( Iomeron )
4- Ioversol ( Optiray )
5- Iopromide ( Ultravist )
• None Ionic – ISO
1- Iotrolan ( Isovist )
2- Iodixanol ( visipaque )
• Chapman / page 27
470
“
“
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•
Chapman / page 25
300
“

8. Dose of IV contrast and
time of scan
Using { 300 mg / ml } will
depending of area examine -- ex
• Head
150 ml
• Chest or abdomen 100 ml
• Children
2ml / kg
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•
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•
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•
•
•Chapman / page 12 , 85,106,109,140,269
In the scanning of abdomen the contrast inject 2ml/s
Chest scanned after 20 s of start injection of contrast
In abdomen or pelvis scanned after 30 s in arterial phase ,
60 s in portal venous phase
For CT angiography bolus tracking of contrast injected
giving optimal acquisition timing
In CT of pancreas , we use –Ve contrast like water , + Ve
contrast ( iodinated ) , oral contrast / scan after 40 s
In cholangiography , contrast infusion for 50 minute / scan
after 35 minute
In T-tube use( LOCM 150 , HOCM) 20ml during operation ,
and 10 day post op
In CT urogram ( LOCM 300 ) 100-150 ml san with 3 mm
slice thickness in 2 minute and 10 minute after contrast
injection
In CT arthrography ( LOCM ) 15 ml in shoulder , 6ml in
elbow , 3 ml in wrist , double –contrast 4ml iodine + 40ml
air
CT contrast injectors

9. Adverse effect of IV contrast
media
• Adverse effect of none ionic iodinated CM are
rare , occurring less than 1%
• Sever or very sever adverse reaction occur in
about 0.044%
• The toxicity is due to function of osmolarity ,
and chemical structure of ionic CM
•This reaction include
1- flushing , nausea , metal taste in moth ,
2- peripheral burning , rigors
3- urticaria , warm , pain , abdominal pain
4- bronchospasm , none cardiac pulmonary
edema
5- arrhythmias , hypotension
6- nephrotoxicity , CIN
7- hematological crisis in sickle cell patient
8- neurotoxicity , thyroid crisis in thyrotoxicosis
patient
9- fetal reaction occurring in about 1.1-1.2 per
million
Identification of patient in high risk of
anaphylactic reaction to IV CM
•
•
•
Previous reaction to CM
Asthma
previous allergic reaction
•
Special concern in patient
complying from
•
•
•
•
•
renal insufficiency GFR < 30 ml/min ,
Serum creatinine > 130 µ mol/l
DM , metformin drug
Old age , Cardiovascular disease
Thyrotoxicosis ,myasthenia gravis
pheochromcytoma , sickle cell disease
•
Chapman / page 27-30

10. Barium compound contrast
• Its made
from barium sulphate
with small particles size ( 0.1-3
mm ) none ionic suspension of
5.3 pH
• barium carbonate is poisonous
• mainly classify according to
the density
* E-Z Cat 1-2% is used in all GIT
CT scan
• Chapman / page 50
• Baritop 100 ( 100% all part of GIT )
• EPI -C
( 150% large bowel )
• E-Z HD
( 250 % esophagus ,
stomach and duodenum )
• E-Z paque ( 100% small bowel )
• Micropaque DC ( 100% eso , stoma
, duo )
• Micropaque liquid ( 100% small and
large bowel )
• Micropaque powder ( 76% small
and large bowel )
• Polibar ( 115% large bowel )
• Polibar rapid ( 100% large bowel )
•
Chapman / page 50

11. Dose of oral contrast and time of scan
• Using of water -soluble 20 ml {Urograffin 150 , gastromiro } diluted in 1
litter
orange squash
• Barium suspension – low density ( 2% w/v )
• Adult dose for abdomen & pelvis ( 1000 ml ) gradually over 1 h before scan
• upper abdomen , pancreas ( 500 ml ) gradually ½ h before scan
• In Large bowel scan we must give the contrast before 4 h or before night / also use
of CO2 for distention of bowel +20 mg buscopan + 1mg glucagon IV using IV contrast
and low dose ( 80 mA ) CT technique scan at 70 s
• in children over 10 years as adult
• newborn 60-90 ml
• below 1 year 120-240 ml
• 1—5 years 240-360 ml
• 5 –10 tears 360- 480 ml
• Full dose 1 h before scan and ½ dose immediately
prior scan
•Chapman / page 13 ,86