Radiographic Contrast
RTEC - A 2010
1. SUBJECT & FILM CONTRAST
2. CONTRAST MEDIA
2 types of Radiographic “Contrast”
1. Subject contrast
patient
1. Film contrast
Inherent in equipment
The BLACKS & WHITES ON THE FILM / IMAGE
“Subject” Contrast
Subject Contrast
Range of differences in the intensity of the x-ray beam
After it has been attenuated by the subject.
SUBJECT CONTRAST
Radiographic object - influenced by
1. Atomic Number of object
2. Density of object
3. Thickness of object
4. 5 materials seen on a radiograph,
Gas/air, fat, soft tissue (muscle/organs),
bone and metals
Atomic Number
1. Fat = 6.46
2. Water = 7.51
3. Muscle = 7.64
4. Bone = 12.31
Tissue
Subject Contrast
1. Atomic # of object
2. Density of object
3. Thickness of object
4. Higher atomic # = more attenuation
5. Denser = more attenuation
6. Thicker = more attenuation
Film Contrast
AKA Radiographic Contrast
Radiographic Contrast influenced by:
1. Radiation Quality (KVP)
2. Film attributes
3. Radiographic object (Patient)
What is good contrast ?
1. High contrast (black and white)
2. Low contrast (more shades of gray)
RADIOGRAPHIC IMAGE
Radiation Quality = kVp
1. High kVp ↑ 80
2. Low contrast
3. Lots shades of gray
4. Long Scale
5. Little differences in adjacent structures
6. Low kVp ↓ 70
7. High contrast
8. Black and White
9. Short Scale
10. Great differences in adjacent structures
QUALITY – KVP
A visible change in contrast will not be seen until kVp is changed 4-12 %
kVp level
change
change in kVp
30-50 kVp
4-5 %
1-3 kVp
50-90 kVp
8-9 %
4-8 kVp
90-130 kVp
10-12 %
9-16 kVp
Scenario
Low subject contrast in the area of interest.
You want to see the difference between muscle & fat & organs?
What can be done to attain medical information and define organ structure and function?
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Scenario
Low subject contrast in the area of interest.
You want to see the difference between muscle & fat & organs?
What can be done to attain medical information and define organ structure and function?
USE CONTRAST MEDIA
Changing Subject Contrast
with CONTRAST MEDIA
Barium has a higher z#
more asorbtion of photons
Contrast Media changes the density of the organs
Purpose of Contrast Media
1. To enhance subject contrast or
render high subject contrast
1. In a tissue that normally has low subject contrast.
2. Creates bigger differences in atomic number (z #’s)
Categories of
Contrast Media
Negative contrast
1. (AIR OR CO2)
2. Radiolucent
3. Low atomic # material
4. Black on film
Positive contrast
1. (all others)
2. Radiopaque
3. High atomic # material
4. White on film
1. RADIOLUCENT - dark on image
AIR, CO2
1. RADIOPAQUE - white on image
BARIUM
IODINE
Negative Contrast
1.
AIR / CO2
2. Naturally seen in the
LUNGS
STOMACH
(gas in intestines)
POSTIVE CONTRAST MEDIA
2 BASIC TYPES OF
‘”Positive” CONTRAST MEDIA
BARIUM Z# 56
KVP 90 – 120*
1. NON WATER SOLUABLE
2. GI TRACT ONLY INGESTED OR RECTALLY
IODINE
Z# 53
KVP BELOW 90*
USUALLY 70 – 80 KvP
1. WATER SOLUABLE
1. POWDER
2. LIQUID
3. INTRAVENOUS OR
4. GI TRACT
2. OIL BASED
1. DUCTS /ORGANS
Positive Contrast Material
INGESTED /INSTILLED
(ORALLY OR RECTALLY)
1. BARUIM
2. IODINES
GASTROGRAFIN
HYPAQUE POWDER
INJECTED
IV – INTO BLOOD VESSELLS
Organs and ducts
1. IODINES
IONIC OR NON-IONIC
VESSELLS & ORGANS
1. OIL BASED
DUCTS /ORGANS ONLY
Methods of Administration
of Contrast Material
1. INGESTED / INSTILLED
(ORALLY OR RECTALLY)
1. INJECTED
IV – INTO BLOOD VESSELLS
1. RETROGRADE
AGAINST NORMAL FLOW (Vessels & Organs)
1. INTRATHECAL
Spinal canal
1. PARENTERAL
2.
(IV, Intrathecal)
Injecting into bloodstream
(anything other than oral)
BARIUM
BARIUM SULFATE
HISTORY OF BARIUM BaSo 4
1. LEAD SUBSTRATE – TOXIC
2. BISMUTH SUBNITRATE – TOXIC
3. THORIUM – RADIOACTIVE
4. BARIUM SULFATE - INERT
1. (goes in and comes out the same – not absorbed)
5.
NOTE SOME PATIENT MAY SHOW ALLERGY TO SUSPENSION SOL.
Barium Sulfate
BaSO+
1. High atomic number
2. Not soluble in water
3. Used to coat the lining of organs
4. Supplied in different thicknesses
5. Used
1. Esophogram, UGI, Small Bowel,Lower GI or BE
Barium Sulfate
BaSO+
1. Because it is not water soluble – it must be mixed in a SUSPENSION with water
2. FLOCCULATION – when barium clumps (separates from the water)
3. Barium residue in the colon can dry and cause an obstruction
4. Drink plenty of fluids after exam
BARIUM
1. MIXED IN A SUSPENSION
2. MUST BE SHAKEN
3. CHECK THE CAP (LID) FIRST !!!!!!!
4. SUSPENSION – sodium citrate, vegetal gums, flavoring and sweeteners to improve palatability
ADVERSE REACTIONS
1. SUSPENSION MAY CAUSE ALLERGY
2. OCG TABLETS (IODINE) ALLERGY
3. AFTER EXAM – MAY SOLIDIFY DIFFICULT TO EVACUATE
4. INCREASE FLUIDS, MILD LAXATIVE
5. EXTRAVASATION OF CONTRAST INTO PERITONEUM
BARIUM CONCENTRATION
1. DIFFERENT FOR EXAMS
2. W/W RATIO (weight/weight)
3. Mixture of barium to water – 100 g suspension
4. “THICK” VS “THIN” BARIUM
BARIUM “THICK & THIN”
1. THICK –
1. DOUBLE CONTRAST
2. THIN –
1. SINGLE CONTRAST
BARIUM
ORAL OR RECTAL
1. LABELS ARE DIFFERENT
2. CHECK CAREFULLY BEFORE GIVING TO THE PATIENT
Palatability OF BARIUM
1. Chalky taste with barium sulphate/water mixture
2. Contain a flavoring agent, sweetners
1. To disguise the unpleasant taste
3. Thicker or thinner suspensions may be used
3. Many commercial preparations contain carboxymethyl cellulose (Raybar, Barosperse)
1. Which retains fluid and prevents precipitation of the barium suspension in the normal small bowel
GASTOINTESTINAL exams
BARIUM COATS LINING OF INTESTINE
1. SINGLE CONTRAST - BARIUM ONLY
2. DOUBLE CONTRAST – WITH AIR
CARBON DIOXIDE TABLETS –
FIZZIES / CRYSTALS
1. SODA
2. ROOM AIR (LOWER GI)
EXTRAVASATION
1. LEAKAGE THROUGH A DUCT OR VESSEL OR ORGAN INTO THE SURROUNDING TISSUE
2. Barium should not be given in cases of suspected perforation
Extravasation
1. Following a Colonoscopy with biopsy
Extravasation of BA in abd
GASTROINTENSTIAL
CONTRAST
MEDIA
PROCEDURES
1. ESOPHOGRAM / OPMS
2. UPPER GI (UGI)
3. SMALL BOWEL (SMBFT)
4. BARIUM ENEMA (BE)
5. GASTRO ENEMA
Drinking Ba for Esophogram
Hiatal Hernia
Reflux “heartburn”
Supplies for BE
“DOUBLE CONTRAST” studies with Barium
1. Air used with other contrast agents
2. Better to see internal structures
DOUBLE CONTRAST EXAMS
1. To achieve double contrast examination of the stomach, air or carbon dioxide gas must be
introduced
2.
Most radiologists use effervescent tablets (sodium bicarbonate , tartaric acid & calcium
carbonate)
3. To react with the gastric contents to produce carbon dioxide
BE
SINGLE
DOUBLE (AC)
UGI
double contrast
single contrast
DOUBLE CONTRAST
WITH IODINE
Iodine mixed with air of a bladder (canine)
IODINE CONTRAST
Iodine
1. Water Soluble
2. High atomic # 53
3. Radiopaque
4. Used to radiograph
Vessels
Arteries
Veins
Function of internal organs
Gastrointestinal system
Ducts
IODINATED CONTRAST
WATER BASED
1. INJECTED
2. VESSELLS/DUCTS
1. Ionic
2. Non-ionic
3. INGESTED or instilled
4. OPEN WOUNDS
OIL BASED
1. INJECTED
2. NEVER VESSELLS
3. ONLY DUCTS
4. NOT INGESTED
5. OPEN WOUNDS
Gastrointestinal studies:
Gastrograffin or Hypaque (Iodine)
1. High atomic #
Close to iodine
1. Water soluble
2. Similar usage as Barium
Gastrograffin
Water soluble iodine-containing contrast media are of value when there is a suspected perforation or
leakage of an anastomosis after operation
Oral or Rectal use
GASTROGRAFIN
POWDERED FORM – MIXED WITH H20
LIQUID IN BOTTLE – MAY BE MIXED
USED WHEN PATIENTS ARE ILL,
SUSPECTED PERFORATIONS
PRE-OPERATIVELY
(BITTER TASTE)
CAN INCREASE PERISTALSIS (SMB STUDY)
GASTROGRAFIN
1. Bitter taste
2. Better if chilled or mixed with ice
3. Monitor patient closely
Gastrograffin via NG tube
Peptic ulcer
1. Use Gastro
2. Contrast may leak
3. Into the peritoneum
4. Causing peritonitis
Gastric neoplasm w/ perforation
EXTRAVASATION OF CONTAST INTO THE PERITONEUM
Gastrografin
enema
SINGLE CONTRAST ENEMA
BARIUM (110 KVP) GASTROGRAFIN (90 KVP)
GASTROGRAFIN
Adverse Reactions
1. Water soluble, safe in the abdominal cavity
Safe to use if perforation is suspected
1. Very harmful to the lung tissue
Do not use if aspiration is possible
Never force contrast
Patient might aspirate into the lungs!
INJECTABLE
CONTRAST MEDIA
INVASIVE PROCEDURES
IVP / IVU
Intravenous injections are INVASIVE
ALWAYS GET PATIENT’S HISTORY AND CONSENT BEFORE BEGINNING
OR GIVING ANY CONTRAST MEDIA
Patient Assessment Check List
Information update !!
INJECTED CONTRAST
1. IODINE BASED
1. IONIC
2. NON IONIC
IODINATED Contrast Agents
IONIC
High Osmolality (Higher risk of complications)
1. (Hypaque)
2. (Conray)
NON-IONIC
Low Osmolality (Lower risk of complications)
1. (Isovue)
Iodine Contrast Material
1. Ionic Contrast
Anion Cation +
More patient allergic reactions
1. Ionic contrast media dissociates into two molecular particles in blood plasma =
2. Causing pt reactions
Newer
Contrast Agents Balance
Safety and Visualization
IODINE WATER BASED CONTRAST
1. IONIC
2. LESS $$$
$25 per bottle
1. MORE REACTIONS
2. NON IONIC
3.
MORE $$$
$200 per bottle
1. LESS REACTIONS
CONTRAST REACTIONS
1. > 10 million diagnostic procedures / year
2. Conventional ionic contrast reactions - 10%
3. 1 in 1000 severe
Allergic to Iodine
General Rule:
1. No Iodine Contrast will be given
1. Pre – medication is available
2. May or may not react if previous iodine given
REACTIONS & Treatment
USUALLY** WITHIN FIRST 5 MINUTES
1. Nausea & Vomiting & Urticaria
2. Hypotension (bradycardia)
3. Hypotension (tachycardia)
4. Bronchospasm
5. Anaphylactoid
6. Seizures
7. Extravasation
ALWAYS –know the location
of drug trays and crash carts
INJECTED IODINE STUDIES
GENITOURINARY
Contrast injected into the VEIN
1. IVP / IVU
2. CYSTOGRAMS
3. (Retrograde may use a foley catheter)
4. GASTROINTESTINAL
5. ERCP – (CBD)
15 MIN POST CONTRAST INJECTION - IVP
Cholelithiasis
GB STONES
Normal ERCP
(checks for stones/blockage in bile duct)
GB STONES
Other Injected
Contrast Studies
Cerebral Angiogram
Renal Arteriogram
MYELOGRAM (SPINAL CORD)
INTRATHECAL INJECTION
Extravasation
“To BE or not to BE”
1. Massive retroperitoneal air
2. pneumomediastinum
3.
subcutaneous air
4.
secondary to bowel perforation
5. after barium enema
Extravasation of Contrast
into soft tissue of arm
Contrast leaking from bladder
OIL – BASED
IODINE
CONTRAST
Oil Based Iodine
1. Fatty Acids
2. Insoluble in water
1. White on the radiograph = Radiopaque
3. Uses
1. Bronchography (lungs)
2. Tear ducts
3. Salivary glands
4. Lymphatic system
5. Hysterrosalpingogram
6. Galactography (breast ducts)
To check fertility
LYMPHANGIOGRAM
Galactography - Breast Duct
Oral & IV contrast
CT Scan
CT showing Abnormal GB
ORAL & IV CONTRAST
(CT/ MRI)