contrast media radiology

1. Contrast media
Pankaj yadav
180528042
Submitted to :- Mr Prashnat Sir
Contrast media are a group of chemical agents developed to aid in the characterization of
pathology by improving the contrast resolution of an imaging modality. Specific contrast media
have been developed for every structural imaging modality, and every conceivable route of
administration. Contrast media are those substances that temporarily change the way light
interacts with the body and/or detectors .Contrast Agents also increases the contrast of targeted
areas of the body on imaging.
Radiography Procedures
 X-rays
 Computed Tomography (CT) Scans
 Fluoroscopy
 Magnetic Resonance Imaging (MRI)
 Ultrasound Contrast Media and etc.
Types of Contrast Media
NEGATIVE CONTRAST :-
 Contrast material that is not radiopaque .
 Low atomic number material .
 Black on film Example: 1) Water, Air and carbon dioxide CONTRAST MEDIA FOR X-
RAY AND CT
POSITIVE CONTRAST
o Contrast material is radiopaque .
o High atomic number material
o White on film Example: 1) Barium sulfate 2) Iodine compounds.
 Iodine-Based :- Given orally, rectally or IV
(Used to enhance contrast on CT scans on all parts of the body, including fluoroscopy)
 Barium-Based :- Given orally or rectally to image the GI tract
(Used to enhance contrast during fluoroscopy)
 Gadolinium-Based :- Given IV only , Paramagnetic
(Alters the magnetic properties of water molecules, enhancing the contrast of MRIs)

2.  Echo Enhancing Agents:- Inject able by a peripheral vein
(Blood pool agents, Liver specific agents, Necrosis specific agents (bis-gadolinium-
mesoporphyrin) used to enhance the contrast of ultrasound)
Contrast reaction
Types of reactions:
1. Anaphylactoid
2. Non-anaphylactoid
Anaphylactoid:- Anaphylactoid reactions occur unexpectedly and the specific cause is
uncertain. Therefore, anaphylactoid reactions are often referred to as “idiosyncratic”. • Other
reactions relating to osmotic, chemotoxic , direct organ toxicity, or vasomotor effects are more
predictable and better understood.
Non-anaphylactoid:- These reactions do not have the characteristics of an
anaphylactoid reaction and are therefore referred to as nonanaphylactoid. • In some
patients, both types of reactions occur, and the result is a combined reaction.
Categories of Reactions
o Mild: nausea, vomiting, cough, sneezing, warmth, headache, dizziness, shaking, altered taste,
itching, pallor, flushing, chills, sweats, rash, hives, nasal stuffiness, anxiety, sneezing,
swelling – eyes, face.
o Moderate: tachycardia / bradycardia, hypertension / hypotension, pronounced cutaneous
reaction, dyspnea, bronchospasm / wheezing.
o Severe: laryngeal edema, convulsions, profound hypotension , clinically manifest
arrhythmias, unresponsiveness, cardiopulmonary arrest.
TYPES AND MANAGEMENT OF ACUTE IDIOSYNCRATIC REACTIONS
Management of mild reactions
Use of ABCDE rule
A – Airway B – Breathing C – Circulation D – Disability E – Exposure Call for help
immediately while resuscitating – do not hesitate INITIAL APPROACH – ABCDE of Critical
care

3. Management of moderate reactions URTICARIA ,Discontinue the injection if not completed
,No Rx in most cases , H1-receptor blocker: Diphenhydramine IV/IM/PO 25-50 mg ,Severe or
widely disseminated urticaria –Adrenaline (1:1000) 0.1- 0.3 ml SC (if no contraindications)
Management of Severe Reactions Oxygen @6-10 L/min (mask) Rapid IV fluids [ Ringer
Lactate/NS) • If poorly responsive, IV Adrenaline 1:10000 1 ml upto max 1 mg dose,
Appropriate assisstance must be sought Secure airway. Oxygen 6-10 L/min ,Monitor vitals ,
Atropine 0.6-1 mg IV slow , max dose upto 0.04mg/kg (2-3 mg) in adult ,Complete resolution
of bradycardia and hypotension before discharge