What do radiologists need to know about contrast media?
Which of the following acute reactions to contrast media usually requires no medical treatment? a. bronchospasm b. laryngeal edema c. urticaria d. convulsions
Is contrast media safe to use?
Mar 21, 2022 · As a precaution, gadolinium-based agents considered at high risk of nephrogenic systemic fibrosis should be avoided in the breastfeeding woman. There is no need to discontinue breastfeeding for 12–48 h after the administration of contrast media and no use in expressing and discarding breast milk following the imaging’.
What are the signs and symptoms of contrast media reactions?
Contrast media reactions may be classified as anaphylactoid, vasomotor, severe or life threatening, and fatal. Anaphylactoid reactions mimic immunoglobulin E-mediated hypersensitivity in that signs may consist of urticaria, angioedema, wheezing, dyspnea, hypotension, or shock. These reactions occur in 2% to 8% of all contrast media infusions.
Can contrast media cause renal failure?
Which of the following reactions to contrast media does NOT usually require treatment? A. Laryngeal edema. B. Nausea and vomiting. C. Dyspnea. D. Bronchospasm.
Which contrast medium is safe?
Iodinated and gadolinium-based contrast media are used on a daily basis in most radiology practices. These agents often are essential to providing accurate diagnoses, and are nearly always safe and effective when administered correctly.Oct 14, 2015
What are the 4 types of contrast media?
Many forms of contrast (gas, liquid, suspension) with many forms of delivery (by mouth, per rectum, intra-luminal, intravenous, and intra-arterial) CT most often uses water-soluble contrast; iodine bound to pharmacologic agents.
What are the three types of contrast media?
What will I experience before and after receiving contrast material?Barium-Sulfate Oral and Rectal Contrast Material. ... Iodine-based Contrast Material. ... Gadolinium-based Contrast Material. ... For all the above administrations of contrast material (barium sulfate, iodine-based, and gadolinium-based):
What is medical term contrast?
A dye or other substance that helps show abnormal areas inside the body. It is given by injection into a vein, by enema, or by mouth. Contrast material may be used with x-rays, CT scans, MRI, or other imaging tests.
What are the five types of contrast?
5 Types of Contrast to Enhance Your Travel PhotosTonal contrast: dark vs. light. Also known as tonal contrast, this is probably the most known type of contrast. ... Colour contrast: warm vs. cold. ... Colour intensity: bright vs. subdued. ... Size matters: big vs. small. ... Meaning: old vs. new.Aug 24, 2016
What are types of contrast?
There are three broad kinds of contrast available: IV, PO, and PR (rectal). IV contrast is either gadolinium for MRI or iodinated contrast for CT. PO contrast for all ER and inpatient CT scans is dilute iodinated contrast (same agent used for IV contrast in CT).
How many types of contrast media are there?
The two main types of iodine-based contrast media are ionic and nonionic. The development of ionic contrast media in the 1920s and 1930s allowed radiologists to visualize vessels and organs on various imaging studies.
What is the most commonly used contrast media?
MRI contrast media are most commonly gadolinium-based contrast agents (GBCAs), which are the agents used for the vast majority of contrast-enhanced MRI scans.Jun 27, 2019
What type of contrast media is used most angiographic procedures?
The radiologist needs to know how your kidneys are functioning before giving contrast. Both gadolinium contrast (used for MRI) and iodinated contrast (used for CT, angiography and other procedures that involve X-rays) leave the body in the urine, which is made by your kidneys.Jul 26, 2017
What does without contrast mean in medical terms?
MRI without contrast is the usual MRI procedure which is done without the use of the contrast agent. The results of the MRI procedure are as valuable and relevant as those done with the use of a contrast agent.
What is negative contrast media?
Negative contrast agents (radiolucent) include air and other gasses. These do not block any x-ray photons, allowing x-rays to easily penetrate tissues containing the air. For example, the air filled lungs appear black on an x-ray because air easily penetrates through the lungs and travel on to expose the x-ray film.
What is the name of contrast dye?
What is gadolinium contrast medium? Gadolinium contrast media (sometimes called a MRI contrast media, agents or 'dyes') are chemical substances used in magnetic resonance imaging (MRI) scans.Jul 26, 2017
What is diagnostic agent?
diagnostic agents instilled into body orifices or injected into vascular system, joints, and ducts to enhance subject contrast in anatomic areas where low subject contrast (similar density to their surrounding structures) exists.
What causes an allergic reaction to shellfish?
Note: shellfish/iodine mith: there is correlation between iodine contrast and allergic reaction; the allergic reaction to shellfish is caused by a protein present in the fish called: tropomyosin. Ionic iodine contrast. Higher-osmolality contrast media; Iodine atoms bonded with sodium or meglumine; Contrast is alien to the body;
How to prevent renal insufficiency?
Renal insufficiency induced by contrast material may be prevented by ensuring adequate hydration and discontinuing other nephrotoxic medications before the procedure. Low-osmolar, nonionic agents are helpful in patients with known conditions associated with adverse reactions.
How many times more likely is a patient to have renal failure before contrast material is administered?
A patient who has renal insufficiency before the administration of contrast material is five to 10 times more likely to develop contrast-induced renal failure than patients in the general population. 6, 7 Patients with a history of anaphylactic reaction to contrast material are more likely to have a similar reaction if they are again exposed to contrast material, but even these patients may not experience repeat reactions on reexposure.
How long does it take for creatinine to rise after contrast?
However, the serum creatinine level often rises within the first 24 hours and peaks in three to five days. The patient's creatinine level usually returns to baseline by seven to 10 days after the procedure.
How is osmolality determined?
The osmolality of a particular contrast agent is determined by the number of osmotically active particles formed when it is dissolved in solution. Ionic agents dissociate into ions when dissolved in water and contain an iodinated benzene ring. As a result, ionic agents have a higher osmolality than blood.
Why are nonionic contrast agents used universally?
Some physicians suggest that nonionic, low-osmolality agents be used universally because fewer adverse reactions are associated with them. Unfortunately, the higher cost of non-ionic agents prohibits their widespread use. Nonionic contrast agents cost up to 10 times more than high-osmolality ionic agents.
What is the risk of renal failure in patients with myeloma?
The risk of renal failure in patients with myeloma is caused by an interaction of light chains and contrast material. How contrast materials cause renal failure is unclear, but direct cellular toxicity and intrarenal vasoconstriction are believed to be the primary causes of renal function changes. 4, 5.
What are the adverse reactions to contrast?
Adverse reactions to contrast agents range from a mild inconvenience, such as itching associated with hives, to a life-threatening emergency. Renal toxicity is a well known adverse reaction associated with the use of intravenous contrast material. Other forms of adverse reactions include delayed allergic reactions, anaphylactic reactions, ...
What is nonionic agent?
Nonionic agents, or low-osmolar/isoosmolar CM, do not dissociate into charged particles when dissolved in water and have one-half the osmolality of ionic agents. As a result, nonionic agents are associated with a considerably lower incidence of ARs, particularly cardiovascular and allergic-like reactions.
How many GBCM are there?
Currently, there are nine gadolinium-based CM (GBCM) approved by the US Food and Drug Administration (FDA) that differ in a number of properties ( Table 20.2 ). Generally, most GBCM present a distribution in the body similar to that of ICM.
What is the osmolality of CM?
Traditional ionic agents, or high-osmolar CM, dissociate into charged particles when dissolved in water and, as a result, have an osmolality 5 to 8 times that of blood (normal blood osmolality is 285–295 mOsm/kg in adults). Charged particles are toxic irritants and can cause allergic reactions.
What happens if you inject air into the venous system?
Unintentional injection of large amounts of air into the venous system may result in dyspnea, expiratory wheezing, chest pain, cough, tachycardia, pulmonary edema, and hypotension. Stroke leading to neurologic deficits may also occur due to decreased cardiac output or paradoxical air embolism.
How long should a patient wait between CM injections?
The American College of Radiology (ACR) recommends that the delay in CM readministration be balanced with the patients severity of renal disease and the medical urgency, whereas the European Society for Urological Radiology (ESUR) recommends the duration of delay be at least 7 days between two injections.
Is GBCM safer than ICM?
However, the mean dose of GBCM delivered is typically 5 to 15 times lower (ranges between 10 and 20 mL) than ICM. This is certainly one of the reasons why GBCM are considered safer to use, and their molecular structure and osmolality are less significant as far as safety is concerned in comparison with ICM .
Why is radiographic CM used?
Radiographic CM are used in imaging examinations to aid in the characterization, detection, and staging of disease. Although the CM currently in use have strong documented safety profiles, their use is not completely without risk.
Introduction
Classification of Contrast Agents and Frequency of Acute Adverse Events
- Iodine-based contrast agents can be divided according to osmolarity (high, low, or iso-), ionicity (ionic or nonionic), and the number of benzene rings (monomer or dimer) (7). Nonionic contrast agents cause less discomfort and fewer adverse reactions compared with ionic agents (7). In current practice, nonionic low or iso-osmolar preparations are used almost exclusively for intrav…
Patient Selection and Preparation
- For any diagnostic procedure, the referring physician and radiologist should consider the risk-to-benefit profile of the proposed contrast material–enhanced examination and potential imaging alternatives that would provide the same or better diagnostic information and confirm a valid clinical indication. Unless state or local regulations require it, obtaining consent for the injection …
Risk Factors
- Although certain patients are at increased risk for an adverse reaction after intravascular contrast media exposure, contrast material reactions remain sporadic and unpredictable (6).
Ct Contrast Agents and Shellfish Allergies
- It is now well established that there is no specific link between shellfish allergy and allergy to contrast agents; there is an increased risk of adverse reactions to contrast agents in patients with any history of allergy (27). The major allergens in shellfish are tropomyosins, which are unrelated to iodine. Iodine is an essential element with no potential to cause an allergic response. If a pati…
Acute Adverse Reactions
- Classification
General adverse reactions to contrast agents remain incompletely understood and are likely multifactorial. Anaphylactoid (idiosyncratic) reactions are unpredictable but constitute most clinically important reactions and involve the release of histamine and other biologic mediators (… - Allergic-like Reactions
The classic allergic reaction requires a sensitizing exposure; however, many patients have allergic-like reactions at initial exposure (29). Serious reactions to contrast media are mediated by type 1 hypersensitivity reaction (anaphylaxis) mechanisms in which the reaction begins within m…
Timing of Reaction Occurrence
- Although most reactions occur in the first hour after administration, and many occur within the first 5 minutes (4), there are rare instances of late adverse reactions that occur between 1 hour and 1 week after injection of iodinated contrast agents (38). Delayed reactions are more common in young adults, women, and patients with a history of allergy (18). The incidence of delayed adv…
Treatment of Acute Nonrenal Adverse Reactions to Contrast Agents
- Treating an acute reaction to a contrast agent can provoke anxiety for all involved. Authors of several recent studies (39–41) have found that many radiologists do not feel well prepared or confident in handing these incidents, particularly the rare severe reactions. Therefore, training to maintain familiarity with methods for evaluation and treatment of reactions and indications for a…
Premedication For Administration of Contrast Material
- Premedication may be considered in patients at risk, but it has not been proven to prevent acute allergic-like reactions (44). Glucocorticoids bind and block proinflammatory genes, such as interleukin-1, to produce anti-inflammatory effects (28). These agents also impair migration of neutrophils, macrophage function, and both cytokine production and degranulation by mast cell…
Breakthrough Reactions
- Sometimes a breakthrough reaction occurs with injection of iodinated contrast agents despite adequate premedication with corticosteroids. These are rare in premedicated patients who are given injections of a low-osmolar contrast agent and usually develop in those already identified as being at high risk. Reaction severity, signs, and symptoms are often reported to be similar to tho…