Radiographic Contrast
RTEC - A 2010
•SUBJECT & FILM CONTRAST
•CONTRAST MEDIA
2 types of Radiographic “Contrast”
Contrast defined as Range of density variations (differences from black to white)
•Subject contrast
–patient
•Film contrast
–Inherent in equipment
–The BLACKS & WHITES ON THE FILM / IMAGE
What is good contrast ?
•High contrast (black and white)
•Low contrast (more shades of gray)
“Subject” Contrast
Subject Contrast
•Range of differences in the intensity of the x-ray beam, after it has been attenuated by
the subject.
Radiographic Contrast : Influenced by…
•Radiation Quality (KVP)
•Film Contrast
•Radiographic object (Patient)
RADIOGRAPHIC IMAGE
Radiation Quality = kVp
•High kVp ↑ 80
•Low contrast
•Many shades of gray
•Long Scale
•Little differences in adjacent structures
•Low kVp ↓ 70
•High contrast
•Black and White
•Short Scale
•Great differences in adjacent structures
QUALITY – KVP
•A visible change in contrast will not be seen until kVp is changed 4-12 %, depending on
kVp range
–kVp level
•
•
•
30-50 kVp
50-90 kVp
90-130 kVp
change
change in kVp
4-5 %
1-3 kVp
8-9 %
4-8 kVp
10-12 % 9-16 kVp
SUBJECT CONTRAST
Radiographic object - influenced by
•Atomic Number of object
•Density of object
•Thickness of object
•5 materials seen on a radiograph,
–Gas/air, fat, soft tissue (muscle/organs),
–bone and metals
Tissue
Subject Contrast
•Atomic # of object
•Density of object
•Thickness of object
•Higher atomic # = more attenuation
•Denser = more attenuation
•Thicker = more attenuation
Atomic Number
•Fat = 6.46
•Water = 7.51
•Muscle = 7.64
•Bone = 12.31
Low Subject Contrast
•What can be done to attain medical information?
•EX: You want to see the difference between muscle & fat & organs?
•Define organ structure and function
•USE CONTRAST MEDIA
Purpose of Contrast Media
•To enhance subject contrast or
render high subject contrast
•in a tissue
that normally has low subject contrast.
•(bigger differences in z#)
Contrast Media changes the density of the organs
Subject Contrast Using
CONTRAST MEDIA
•RADIOLUCENT
- dark on image
–AIR, CO2
•RADIOPAQUE –BARIUM
white on image
–IODINE
Contrast Media
Negative contrast
•(AIR OR CO2)
•Radiolucent
•Low atomic # material
•Black on film
Positive contrast
•(all others)
•Radiopaque
•High atomic # material
•White on film
TYPES OF CONTRAST USED IN
RADIOLOGY NEGATIVE DENSITY
 AIR / CO2
Naturally seen in the
 LUNGS
 STOMACH
(gas in intestines)
TYPES OF CONTRAST USED IN
RADIOLOGY NEGATIVE DENSITY
 AIR / CO2
Mixing with other contrast media (barium or iodine)
Can give more information about the area under examiniation
“DOUBLE CONTRAST” studies with Barium
Air used with other contrast agents
Better to see internal structures
DOUBLE CONTRAST
WITH IODINE
Iodine mixed with air of a bladder (canine)
Changing Subject Contrast
with CONTRAST MEDIA
POSTIVE CONTRAST MEDIA
•IODINE OR
BARIUM
•X-RAY “DYE”
•INCORRECT
TERM
•COLORLESS OR WHITE
2 BASIC TYPES OF
‘”Positive” CONTRAST MEDIA
BARIUM Z# 56
KVP 90 – 120*
•NON WATER SOLUABLE
•GI TRACT ONLY INGESTED OR RECTALLY
IODINE Z# 53
KVP BELOW 90*
USUALLY 70 – 80 KvP
•WATER SOLUABLE
•POWDER
•LIQUID
•INTRAVENOUS OR
•GI TRACT
•or OIL BASED
•DUCTS /ORGANS
Contrast Material
INGESTED /INSTILLED
–(ORALLY OR RECTALLY)
•BARUIM
•IODINES
–GASTROGRAFIN
–HYPAQUE POWDER
INJECTED
–IV – INTO BLOOD VESSELLS
– Organs and ducts
•IODINES
–IONIC OR NON-IONIC
•VESSELLS & ORGANS
•OIL BASED
–DUCTS /ORGANS ONLY
Methods of Administration
of Contrast Material
•INGESTED / INSTILLED
–(ORALLY
OR RECTALLY)
•INJECTED
–IV
– INTO BLOOD VESSELLS
•RETROGRADE
–AGAINST NORMAL FLOW (Vessels & Organs)
•INTRATHECAL
–Spinal canal
•PARENTERAL
• (IV, Intrathecal)
–Injecting into bloodstream
–(anything other than oral)
BARIUM
BARIUM SULFATE
HISTORY OF BARIUM BaSo 4
•LEAD SUBSTRATE – TOXIC
•BISMUTH SUBNITRATE – TOXIC
•THORIUM – RADIOACTIVE
•BARIUM SULFATE - INERT
–(goes in and comes out the same – not absorbed)
• NOTE SOME PATIENT MAY SHOW ALLERGY TO SUSPENSION SOL.
Barium Sulfate
BaSO+
•High atomic number
•Not soluble in water
•Used to coat the lining of organs
•Supplied in different thicknesses
•Used
–Esophogram, UGI, Small Bowel,Lower GI or BE
Barium Sulfate
BaSO+
•Because it is not water soluble – it must be mixed in a SUSPENSION with water
•FLOCCULATION – when barium clumps (separates from the water)
•Barium residue in the colon can dry and cause an obstruction
•Drink plenty of fluids after exam
BARIUM CONCENTRATION
•DIFFERENT FOR EXAMS
•W/W RATIO (weight/weight)
•Mixture of barium to water – 100 g suspension
•“THICK” VS “THIN” BARIUM
BARIUM “THICK & THIN”
•THICK – USED FOR
•DOUBLE CONTRAST
•THIN – SINGLE CONTRAST
BARIUM
ORAL OR RECTAL
•LABELS ARE DIFFERENT
•CHECK CAREFULLY BEFORE GIVING TO THE PATIENT
BARIUM SULFATE
Palatability OF BARIUM
•Chalky taste with barium sulphate/water mixture
•Contain a flavoring agent, sweetners
•To disguise the unpleasant taste
•Thicker or thinner suspensions may be used
•Many commercial preparations contain carboxymethyl cellulose (Raybar, Barosperse),
•Which retains fluid and prevents precipitation of the barium suspension in the normal
small bowel
DOUBLE CONTRAST EXAMS
•To achieve double contrast examination of the stomach, air or carbon dioxide gas must
be introduced
• Most radiologists use effervescent tablets (sodium bicarbonate , tartaric acid & calcium
carbonate)
•to react with the gastric contents to produce carbon dioxide
GASTOINTESTINAL exams
•BARIUM COATS LINING OF INTESTINE
–SINGLE CONTRAST - BARIUM ONLY
–DOUBLE CONTRAST – WITH AIR
•CARBON DIOXIDE TABLETS –
• FIZZIES / CRYSTALS
–SODA
–ROOM AIR (LOWER GI)
“DOUBLE CONTRAST” studies with Barium
–Air used with other contrast agents
–Better to see internal structures
BARIUM
•MIXED IN A SUSPENSION
•MUST BE SHAKEN
•CHECK THE CAP (LID)
FIRST !!!!!!!
•SUSPENSION – sodium citrate, vegetal gums, flavoring and sweeteners to improve
palatability
ADVERSE REACTIONS
•SUSPENSION MAY CAUSE ALLERGY
•OCG TABLETS (IODINE) ALLERGY
•AFTER EXAM – MAY SOLIDIFY DIFFICULT TO EVACUATE
•INCREASE FLUIDS, MILD LAXATIVE
•EXTRAVASATION OF CONTRAST INTO PERITONEUM
EXTRAVASATION
•LEAKAGE THROUGH A DUCT OR VESSEL OR ORGAN INTO THE
SURROUNDING TISSUE
•Barium should not be given in cases of suspected perforation
GASTROINTENSTIAL
CONTRAST
MEDIA
PROCEDURES
•ESOPHOGRAM / OPMS
•UPPER GI (UGI)
•SMALL BOWEL (SMBFT)
•BARIUM ENEMA (BE)
•GASTRO ENEMA
Drinking Ba for Esophogram
Hiatal Hernia
UGI
double contrast
Reflux “heartburn”
single contrast
Be Kind to your patientsoffer them a wet towel for the Ba mustache !
SMB
Enteroclysis
BARIUM
BARIUM ENEMA
Supplies for BE
BE
SINGLE
DOUBLE (AC)
SINGLE VS DOUBLE CONTRAST
BARIUM ENEMA
Extravasation
–Following a Colonoscopy with biopsy
IODINE CONTRAST
•INGESTED FOR
INTESTINAL STUDIES
Alternative to BA contrast:
Gastrograffin or Hypaque (Iodine)
•High atomic #
–Close to iodine
•Water soluble
•Similar usage as Barium
Gastrografin
•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
Bitter taste
Better if chilled or mixed with ice
Monitor patient closely
Gastrografin via NG tube
Peptic ulcer
•Use Gastro
•Contrast may leak
•Into the peritoneum
•Causing peritonitis
Gastric neoplasm w/ perforation
•EXTRAVASATION OF CONTAST INTO THE PERITONEUM
Gastrografin
enema
SINGLE CONTRAST ENEMA
BARIUM (110 KVP) GASTROGRAFIN (90 KVP)
“To BE or not to BE”
•Massive retroperitoneal air
•pneumomediastinum
• subcutaneous air
• secondary to bowel perforation
•after barium enema
Extravasation of BA in abd
GASTROGRAFIN
Adverse Reactions
•Water soluble, safe in the abdominal cavity
–Safe to use if perforation is suspected
•Very harmful to the lung tissue
–Do not use if aspiration is possible
Never force contrast
Patient might aspirate into the lungs!
KVP
RANGE
BARIUM
90 – 120 kVp
(Range due to: Thick vs thin vs double contrast)
IODINES 70 – 80 kVp
(Ionic / Nonionic Water or Oil)
INJECTABLE
CONTRAST MEDIA
INVASIVE PROCEDURES
IVP / IVU
Iodine
•Water Soluble
•High atomic # 53
•Radiopaque
•Used to radiograph
–Vessels
–Arteries
–Veins
–Function of internal organs
INJECTABLE
IODINE - NONIONIC
Newer
Contrast Agents Balance
Safety and Visualization
IODINATED CONTRAST
WATER BASED
•INJECTED
•
• VESSELLS/DUCTS
•INGESTED
•OPEN WOUNDS
OIL BASED
•INJECTED
•NEVER VESSELLS
•ONLY DUCTS
•
•NOT INGESTED
•OPEN WOUNDS
IODINE WATER BASED CONTRAST
•IONIC
•LESS $$$
–$25 per bottle
•MORE REACTIONS
•NON IONIC
• MORE $$$
–$200 per bottle
•LESS REACTIONS
Iodine Contrast Material
•Ionic Contrast
–Anion –Cation +
–More patient allergic reactions
•Ionic contrast media dissociates into two molecular particles in blood plasma =
•Causing pt reactions
CONTRAST MEDIA
•IONIC CONTRAST
benzene ring
•NON IONIC CONTRAST
IODINATED Contrast Agents
IONIC
•High Osmolality (Higher risk of complications)
–(Hypaque)
–(Conray)
NON-IONIC
•Low Osmolality (Lower risk of complications)
•(Isovue)
Intravenous injections are INVASIVE
ALWAYS GET PATIENT’S HISTORY AND CONSENT BEFORE BEGINNING
OR GIVING ANY CONTRAST MEDIA
Patient Assessment Check List
•Information update !!
CONTRAST REACTIONS
> 10 million diagnostic procedures / year
Conventional ionic contrast reactions - 10%
1 in 1000 severe
Allergic to Iodine
General Rule:
•No Iodine Contrast will be given
–Pre – medication is available
•May or may not react
if previous iodine given
INJECTED CONTRAST
•IODINE BASED
•IONIC OR
•NON IONIC
INJECTED IODINE STUDIES
GENITOURINARY
Contrast injected into the VEIN
IVP / IVU
CYSTOGRAMS
(Retrograde may use a foley catheter)
GASTROINTESTINAL
ERCP – (CBD)
15 MIN POST CONTRAST INJECTION - IVP
REACTIONS & Treatment
USUALLY** WITHIN FIRST 5 MINUTES
•Nausea & Vomiting & Urticaria
•Hypotension (bradycardia)
•Hypotension (tachycardia)
•Bronchospasm
•Anaphylactoid
•Seizures
•
•Extravasation
ALWAYS –know the location
of drug trays and crash carts
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 of Contrast
into soft tissue of arm
Contrast leaking from bladder
OIL – BASED
IODINE
CONTAST
Oil Based Iodine
•Fatty Acids
•Insoluble in water
–White on the radiograph = Radiopaque
•Uses
–Broncography (lungs)
–Tear ducts
–Salivary glands
–Lymphatic system
–Hysterrosalpingogram
–Galactography (breast ducts)
To check fertility
LYMPHANGIOGRAM
Galactography - Breast Duct
Oral & IV contrast
CT Scan
CT showing Abnormal GB
ORAL & IV CONTRAST
(CT/ MRI)
CAT SCAN
The end of contrast &
Contrast media
RT A - 2009