Related Experiment Video
Updated: May 2, 2026
Percutaneous Contrast Echocardiography-guided Intramyocardial Injection and Cell Delivery in a Large Preclinical Model
Published on: January 21, 2018
Perflutren lipid microspheres for echocardiogram contrast: a clinical case of anaphylaxis not caused by PEG
Chloe Wang1,2, Jackie Campbell2, Harriet Lea-Banks3,4
1Faculty of Science and Schulich School of Medicine & Dentistry, Western University, London, ON, Canada.
Background:
Perflutren lipid microsphere suspension, sold under the brand name Definity®, is a microbubble ultrasound contrast agent. The microspheres contain octafluoropropane (C3F8) gas encapsulated by an outer lipid shell of phospholipids and a polyethylene glycol (PEG)ylated phospholipid. Anaphylaxis to perflutren lipid microsphere is very rare, with only one case report clearly attributing the reaction to the PEG excipient. We report a novel case of anaphylaxis likely caused by a non-PEGylated component of Definity®.
Case Presentation:
Our patient is a healthy 54-year-old female, who underwent an exercise stress transthoracic echocardiogram using Definity® as an enhancing agent. She experienced anaphylaxis within 15 min of injection. Symptoms resolved after she was treated with diphenhydramine and epinephrine, followed by a systemic corticosteroid and ondansetron in the Emergency Department. The patient underwent allergy testing at our clinic for Definity® and various PEG-containing substances. While all PEG products tested negative, she had positive intradermal tests to Definity®. She also had negative skin prick testing to PEG 8000 and passed an oral challenge to PEG 3350, thus ruling out PEG as the causative agent of anaphylaxis.
Conclusions:
Our case report highlights a previously undocumented instance of anaphylaxis to Definity® not caused by PEG. We suspect the reaction to be an IgE-mediated response to a non-PEGylated component of Definity®. An alternative explanation for the reaction could be a complement activation-related pseudoallergy. This report provides critical information to physicians on the potential risks of using Definity® and contributes to growing research surrounding the profile of Definity®.
Insights
Anaphylaxis to Definity®, an ultrasound contrast agent, can occur due to non-polyethylene glycol (PEG) components. Allergy testing confirmed Definity® as the cause, not PEG, suggesting a novel hypersensitivity reaction.
Area of Science:
- Allergy and Immunology
- Radiology
- Pharmacology
Background:
- Perflutren lipid microsphere suspension (Definity®) is an ultrasound contrast agent composed of octafluoropropane gas, phospholipids, and PEGylated phospholipids.
- Anaphylaxis to Definity® is rare, with previous reports suggesting polyethylene glycol (PEG) as a potential allergen.
- This report details a case where anaphylaxis was likely caused by a non-PEGylated component of Definity®.
Purpose of the Study:
- To report a novel case of anaphylaxis to Definity®.
- To investigate the causative agent of anaphylaxis in a patient who received Definity®.
- To differentiate between PEG-mediated and non-PEG-mediated hypersensitivity to Definity®.
Main Methods:
- A 54-year-old female experienced anaphylaxis post-Definity® injection during an echocardiogram.
- Allergy testing included intradermal tests for Definity® and various PEG-containing substances, as well as skin prick testing and oral challenge for PEG.
- Treatment involved standard anaphylaxis management, including diphenhydramine, epinephrine, corticosteroids, and ondansetron.
Main Results:
- The patient developed anaphylaxis within 15 minutes of Definity® injection.
- Allergy testing was negative for PEG-containing substances but positive for Definity® via intradermal testing.
- Symptoms resolved with appropriate medical treatment.
Conclusions:
- This case highlights a previously undocumented cause of anaphylaxis to Definity®, unrelated to PEG.
- The reaction is suspected to be an IgE-mediated response or complement activation-related pseudoallergy to a non-PEGylated component.
- Physicians should be aware of potential non-PEG-related hypersensitivity reactions to Definity®.
Related Concept Videos
02:06Allergic Reactions
01:25Antiasthma Drugs: Mast Cell Stabilizers and Anti-IgE Drugs
Mast cell stabilizers, such as cromolyn (also known as sodium cromoglycate) and nedocromil (Tilade), are effective drugs in asthma management. These stabilizers hinder histamine release by skillfully obstructing the activation of mast cells and other cellular entities. Notably, they navigate this task without...
01:17Imaging Studies for Cardiovascular System I:Echocardiography
Indications: Echocardiography is utilized to diagnose heart failure, valve disorders, and myocardial infarction. It also assesses cardiac structures' size, shape, and motion,...
01:20Imaging Studies for Cardiovascular System II:Types of Echocardiography
Types of Echocardiography
Transthoracic Echocardiography (TTE)
TTE is the most common type of echocardiogram which involves placing a transducer on the patient's chest, emitting sound waves to create heart images. TTE is invaluable for evaluating the heart's size, structure, and motion, making it particularly useful for...