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Objective: To determine whether updated guidance by the ACR in 2017 advocating use of intravenous (IV) premedication in emergency department (ED) patients and inpatients with reported iodinated contrast allergy was associated with a change in clinical practice., Methods: An anonymous survey was distributed via e-mail in October 2020 to practicing radiologist members of the ACR interrogating use of corticosteroid premedication for two clinical vignettes: an indicated routine (perform within 24 hours) inpatient contrast-enhanced CT (CE-CT) and an indicated urgent (perform within 6 hours) ED CE-CT. In both scenarios, the patient had a prior moderate hypersensitivity reaction to iodinated contrast media. Clinical management was evaluated. Data were compared to historical controls from 2009., Results: The response rate was 11% (724 of 6,616). For the inpatient scenario, 72% (518 of 724) would use corticosteroid premedication with CE-CT, and 28% (200 of 724) would perform noncontrast CT. For the ED scenario, 67% (487 of 724) would use corticosteroid premedication with CE-CT, and 30% (217 of 724) would perform noncontrast CT. Oral premedication (85%, 439 of 518) was preferred for routine inpatients, and rapid IV premedication (89%, 433 of 487) was preferred for urgent ED patients. Of those who provided rapid IV dosing data in the ED, two doses of corticosteroids were used by 53% (216 of 410) and one dose was used by 45% (185 of 410), with academic radiologists more likely than private or hybrid practice radiologists to administer two doses (74% [74 of 100] versus 48% [151 of 312], P < .001, odds ratio, 3.03; 95% confidence interval, 1.84-5.00). Rapid IV premedication was more commonly used in 2020 than in 2009 (60% [433 of 724] versus 29% [20 of 69], P < .001, odds ratio, 3.65; 95% confidence interval, 2.12-6.26). Antihistamine use was common in both inpatient (93%, 480 of 518) and ED settings (92%, 447 of 487). Only 32% (229 of 721) of radiologists practiced in accordance with ACR guidelines, suggesting no need for routine premedication before CE-CT in patients with prior severe hypersensitivity reaction to gadolinium-based contrast media. Nonetheless, most (93%, 670 of 724) said the ACR Manual on Contrast Media was a major determinant of their practice., Conclusions: Use of rapid IV premedication in urgent settings has increased since 2009, following updated ACR guidelines, but there is disagreement over whether one or two corticosteroid doses is required. Despite reported high reliance on ACR guidelines, deviations from those guidelines remain common. In general, when ACR guidelines were not followed, it was in a risk-averse direction., (Copyright © 2023 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Purpose To determine if the allergic-like breakthrough reaction rate of intravenous corticosteroid prophylaxis administered 5 hours before contrast material-enhanced computed tomography (CT) is noninferior to that of a traditional 13-hour oral regimen. Materials and Methods Institutional review board approval was obtained and informed consent waived for this retrospective noninferiority cohort study. Subjects (n = 202) who completed an accelerated 5-hour intravenous corticosteroid premedication regimen before low-osmolality contrast-enhanced CT for a prior allergic-like or unknown-type reaction to iodine-based contrast material from June 1, 2008, to June 30, 2016, were identified. The breakthrough reaction rate was compared by using the Farrington and Manning noninferiority likelihood score to test subjects premedicated with a traditional 13-hour oral regimen (2.1% [13 of 626]). All subjects were premedicated for a prior allergic-like or unknown-type reaction to iodine-based contrast material. A noninferiority margin of 4.0% was selected to allow for no more than a clinically negligible 6.0% breakthrough reaction rate in the cohort that received 5-hour intravenous corticosteroid prophylaxis. Results The breakthrough reaction rate for 5-hour intravenous prophylaxis was 2.5% (five of 202 patients; 95% confidence interval: 0.8%, 5.7%), which was noninferior to the 2.1% (13 of 626 patients; 95% confidence interval: 1.1%, 3.5%) rate for the 13-hour regimen (P = .0181). The upper limits of the confidence interval for the difference between the two rates was 3.7% (0.4%; 95% confidence interval: -1.6%, 3.7%), which was within the 4.0% noninferiority margin. All breakthrough reactions were of equal or lesser severity to those of the index reactions (two severe, one moderate, and one mild reaction). Conclusion Accelerated intravenous premedication with corticosteroids beginning 5 hours before contrast-enhanced CT has a breakthrough reaction rate noninferior to that of a 13-hour oral premedication regimen. © RSNA, 2017.

Corticosteroid prophylaxis is commonly used for the prevention of allergiclike reactions to iodinated and gadolinium-based contrast material in patients at highest risk of an allergiclike reaction. However, it has only a weak mitigating effect on allergiclike reactions, probably does not affect the severity of subsequent reactions, and does not prevent all reactions. Breakthrough reactions occur, are usually the same severity as the index reaction, and can occasionally be life threatening. Premedication of inpatients is likely associated with substantial cost and harm because of hospital length-of-stay prolongation; these indirect effects may exceed the benefits of premedication in this population., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: To evaluate the effect of available intravenous (IV) access on the accuracy and timeliness of epinephrine administration during a surprise mock severe contrast reaction., Methods: Informed consent was waived for this prospective randomized IRB-approved study. Radiology trainees with previous annual hands-on contrast reaction training (n = 46) were randomized to one of two surprise mock contrast reactions over a 23-month period: Group 1-severe laryngeal edema with IV access present (n = 27) or Group 2-severe laryngeal edema without IV access present (n = 19). Both intramuscular (IM, Epi-Pen(®)) and IV epinephrine were available in both scenarios. Time-to-treat and epinephrine administration error rates were compared by study group and by route of administration using two-tailed Student's t test or χ (2) test. Epinephrine administration errors were correlated with training experience using Pearson's correlation., Results: Mean time to epinephrine administration was significantly faster for scenarios without IV access (Group 2: 35 ± 16 s vs. Group 1: 62 ± 49 s, p = 0.03), and for intramuscular administrations overall (IM: 42 ± 34 s vs. IV: 98 ± 46 s, p < 0.001). Epinephrine administration errors were common: (63% [17/27, Group 1] vs. 61% [11/18, Group 2], p = 1.00), had no relationship with time to most recent hands-on training (r = 0.24, p = 0.11), and were not predicted by year of post-graduate training (r = 0.04, p = 0.79)., Conclusions: Lack of IV access is associated with a faster epinephrine administration time but no improvement in epinephrine administration error rate among radiology trainees responding to a surprise mock severe contrast reaction. Annual hands-on training appears to have little effect on epinephrine administration accuracy.

Objective: The purpose of this study was to determine the rate of allergiclike breakthrough reactions among inpatients at high risk receiving premedication before undergoing CT with IV iodinated low-osmolality contrast material (LOCM)., Materials and Methods: Inpatients (n = 1051) completing a 13-hour corticosteroid and diphenhydramine premedication regimen before LOCM-enhanced CT from January 1, 2010, through December 31, 2013, were included in the study. Breakthrough reaction rates were compared with the ordinary allergiclike reaction rate in the general population (0.6% [545/84,928]) by use of chi-square tests. Multivariate logistic regression was performed. Number needed to treat (NNT) was calculated for patients premedicated for a previous contrast reaction., Results: Sixty percent (626/1051) of premedicated patients had had a previous reaction to iodinated contrast material, and 40% (425/1051) were premedicated for other reasons. The overall breakthrough reaction rates were 1.2% (13/1051) (p < 0.0001 vs the general population), 2.1% (13/626) for those with a previous iodinated contrast reaction (p < 0.0001), and 0% (0/425) for those premedicated for other reasons (p = 0.18). There were no severe breakthrough reactions. Younger age (p = 0.046; odds ratio, 1.03 per year; 95% CI, 1.001-1.07) and multiple indications for premedication (p < 0.0001; odds ratio, 2.7 per indication; 95% CI, 1.5-4.8) significantly increased the likelihood of a breakthrough reaction. The estimated NNTs were 69 (95% CI, 39-304) to prevent a reaction of any severity and 569 (95% CI, 389-1083) to prevent a severe reaction., Conclusion: Patients premedicated for a previous reaction to iodinated contrast material have a breakthrough reaction rate 3-4 times the ordinary reaction rate in the general population. Patients receiving premedication for other reasons have a breakthrough reaction rate near 0%. Many patients must receive premedication to prevent one reaction.

Purpose: To evaluate the effect of abruptly substituting gadobenate dimeglumine for gadopentetate dimeglumine on allergic-like reactions., Materials and Methods: The institutional review board approved and waived patient consent for this HIPAA-compliant retrospective study. Allergic-like reactions related to gadolinium-based contrast media were assessed 2 years before and 3.5 years after gadobenate dimeglumine was substituted for gadopentetate dimeglumine. Reaction rates and severity were compared by using χ(2) tests, Fisher exact tests, odds ratios (ORs), and confidence intervals (CIs)., Results: Allergic-like reactions (137 mild, 19 moderate, and six severe) occurred in 162 (0.15%) of 105 607 injections of gadolinium-based contrast media (gadopentetate dimeglumine, 31 540; gadobenate dimeglumine, 66 152; other, 7915). Gadobenate dimeglumine was associated with significantly more overall (0.19% [123 of 66 152] vs 0.08% [24 of 31 540]; OR, 2.4; 95% CI: 1.6, 3.8; P < .0001) and mild (0.16% [107 of 66 152] vs 0.06% [18 of 31 540]; OR, 2.8; 95% CI: 1.7, 4.7; P < .0001) allergic-like reactions than was gadopentetate dimeglumine. The reaction rate for gadobenate dimeglumine peaked (maximum per quarter, 0.38% [16 of 4262]; minimum per quarter, 0.07% [three of 4237]) in the 2nd year after it replaced gadopentetate dimeglumine (maximum per quarter, 0.10% [four of 4122]; minimum per quarter, 0.05% [two of 4222]) and then declined in the 3rd year. The final gadobenate dimeglumine reaction rate (last 3 quarters, 0.12% [17 of 14 387]) did not significantly differ from the original baseline reaction rate with gadopentetate dimeglumine., Conclusion: After gadobenate dimeglumine was substituted for gadopentetate dimeglumine, a significant transient increase occurred in the frequency of reported allergic-like reactions that demonstrated a temporal pattern suggestive of the Weber effect (a transient increase in adverse event reporting that tends to peak in the 2nd year after a new agent or indication is introduced). © RSNA, 2012.

Background: There are few data available concerning the use of intravenous contrast materials in children., Objective: To assess patterns of intravenous iodinated/gadolinium-based contrast material (ICM/GBCM) use in children., Materials and Methods: Society of Chairs of Radiology in Children's Hospitals (SCORCH) members were invited to complete a Web-based survey regarding intravenous contrast material use at their institutions., Results: Sixty-six percent (42/64) of SCORCH member institutions responded, 76% of which are academic hospitals. Ioversol and gadopentetate dimeglumine are the most commonly used ICMs and GBCMs (52% and 81%, respectively). Premedication policies to mitigate risk of allergic-like contrast reactions are more common for ICMs than GBCMs (71% vs. 32%). For both ICMs and GBCMs, most institutions premedicate or avoid contrast material in the setting of a prior allergic-like contrast reaction of any severity. Policies regarding ICM and GBCM use in children with renal insufficiency are in place at 74% and 88% of institutions, respectively, but are variable., Conclusion: Policies concerning premedication for prevention of allergic-like contrast agent reactions and administration of contrast materials in children with renal insufficiency are variable and not consistently present at all pediatric institutions. This highlights the need for standardization of practice patterns and pediatric-specific research on these topics.

Purpose: To determine the frequency, type, and severity of breakthrough and repeat breakthrough reactions to iodinated low-osmolality contrast medium (LOCM) in patients who were premedicated with corticosteroids and antihistamines., Materials and Methods: Institutional review board approval was obtained, and informed consent was waived for this retrospective HIPAA-compliant analysis. One hundred ninety breakthrough allergic-like reactions to intravenous LOCM in 175 patients with a history of contrast medium reactions were reviewed. The repeat breakthrough reactions that resulted from 197 additional LOCM-enhanced examinations performed in 58 patients after the initial breakthrough reaction were also reviewed. The Fisher exact test was used to determine if certain risk factors were associated with an increased risk of a moderate or severe breakthrough reaction. Subgroup analysis was performed to determine if the contrast medium type, contrast medium volume, and/or time between the initial (index) and breakthrough reactions affected the breakthrough reaction severity., Results: Of 128 breakthrough reactions in which the index reaction severity was known, 103 (81%) were of a severity similar to that of the index reaction, 15 (12%) were less severe, and 10 (8%) were more severe. The severity of the breakthrough reactions in the patients with a mild index reaction was usually (in 94 [91%] of 103 reactions) mild. When the index reaction was severe, the breakthrough reaction was usually moderate or severe (in eight [42%] of 19 cases and four [67%] of six cases, respectively). The majority (174 [88%] of 197) of LOCM injections after the initial breakthrough reaction did not result in a repeat breakthrough reaction. Breakthrough reactions were significantly more likely to be moderate or severe in patients with a history of chronic oral corticosteroid use (P = .01), drug (P = .04) or severe (P < .001) allergies, or allergies to four or more allergens (P = .01)., Conclusion: Breakthrough reactions are usually similar in severity to the index reaction, and subsequent contrast medium injections usually do not induce repeat breakthrough reactions. Breakthrough reactions are more likely to be moderate or severe in patients with certain risk factors., ((c) RSNA, 2009.)

Objective: The objective of our study was to evaluate the frequency, outcome, and appropriateness of treatment of adults with acute allergiclike reactions related to IV-administered nonionic iodinated contrast media., Materials and Methods: For IV injections of nonionic iodinated contrast media between January 1, 1999, and December 31, 2005, contrast reaction reports and medical records of patients in whom contrast reactions occurred were reviewed. Data collected included patient sex and age, symptoms, reaction manifestations, treatment, and long-term sequelae. The appropriateness and efficacy of patient management were assessed., Results: Allergic-type reactions occurred in 545 (0.6%) of patients injected with nonionic iodinated contrast media: 418 (77%) reactions were mild, 116 (21%) were moderate, and 11 (2%) were severe. Two hundred twenty-one patients (41%) received treatment. The most commonly administered medication was diphenhydramine (145 patients or 27%). Corticosteroids were administered to 17 patients, nebulized albuterol to 16, and epinephrine to 15. Although 99% of the treatments did not result in any complication, three patients may have had short-term sequelae as a result of receiving a nonrecommended treatment., Conclusion: Patients usually do well after developing acute allergiclike reactions to nonionic iodinated contrast media. Fortunately, in our series, this was true even in the rare cases in which the instituted treatment was considered to be inappropriate. Reacting patients rarely develop serious long-term sequelae.

Objective: The objective of our study was to determine the number and severity of allergic-like breakthrough reactions to i.v. gadolinium-containing contrast agents in children and adults after premedication with corticosteroids and antihistamines., Materials and Methods: Contrast material reaction forms from the department of radiology for pediatric (under 19 years old) and adult patients were reviewed for the time period from January 1, 2001, through December 31, 2006. All documented allergic-like reactions to i.v. gadolinium-containing contrast media after premedication with corticosteroids and antihistamines were identified. Forms were evaluated for reaction manifestations, management, and patient outcome. Our institutional electronic medical record system was accessed for each individual patient to identify pertinent medical history, including demographic information, history of allergic-like reaction to contrast media (gadolinium- or iodine-containing), and additional factors that led to prophylactic premedication., Results: Eight patients experienced nine allergic-like reactions after the i.v. administration of gadolinium-containing contrast media despite premedication. A single patient had two breakthrough reactions. Six breakthrough reactions were mild, and three were moderate. No severe or fatal breakthrough reaction occurred. Eight of nine breakthrough reactions occurred in adults. All patients who experienced breakthrough reactions had a history of allergic-like reaction to either gadolinium- or iodine-containing contrast media., Conclusion: Allergic-like reactions to gadolinium-containing contrast media can occur despite premedication with corticosteroids and antihistamines.

Objective: The purpose of our study was to determine the frequency and severity of acute allergic-like reactions to i.v.-administered gadolinium-containing contrast media in children and adults., Materials and Methods: Pediatric (younger than 19 years) and adult department of radiology contrast material reaction forms involving patients who experienced acute allergic-like reactions to gadolinium-containing contrast media from January 1, 2001, through December 31, 2006, were retrospectively evaluated for the specific types of acute allergic-like reactions, reaction management, and patient outcomes. Relevant patient medical information, including documentation of prior gadolinium- or iodine-containing contrast material reaction, premedication before acute allergic-like reaction to i.v. gadolinium-containing contrast material, previous allergic reactions to substances other than contrast media, and history of asthma, was obtained by reviewing electronic medical records., Results: Seventy-eight thousand three hundred fifty-three (65,009 adult and 13,344 pediatric) i.v. administrations of gadolinium-containing contrast material were performed during the study period. Acute allergic-like reactions were documented after 54 injections (reaction frequency, 0.07%). Forty-eight reactions involved adult patients (adult reaction frequency, 0.07%), and six reactions occurred in pediatric patients (pediatric reaction frequency, 0.04%). Forty (74%) acute allergic-like reactions were mild, 10 (19%) were moderate, and four (7%) were severe. No gadolinium-containing contrast material-related death occurred during the study period. Twenty-six (50%) of 52 patients had one or more presumed risk factors for contrast material reaction., Conclusion: Adult and pediatric acute allergic-like reactions to i.v.-administered gadolinium-containing contrast media are rare. Most of these reactions are mild; however, moderate and severe reactions that require immediate management do occur.

Objective: The purpose of this study was to evaluate the incidence and severity of acute allergic-like reactions related to i.v. administration of low-osmolality nonionic iodinated contrast material in children., Materials and Methods: Department of radiology contrast material reaction forms involving pediatric (younger than 19 years) imaging examinations performed from January 1, 1999, through June 30, 2006, were retrospectively evaluated for type of acute allergic-like reaction, severity of reaction, and patient outcome. The electronic medical record was reviewed for pertinent medical history related to each acute reaction, including previous contrast material reaction, premedication before administration of i.v. iodinated contrast material, previous allergic-like reaction to substances other than contrast material, and history of asthma., Results: In our department during the time period specified, 11,306 pediatric i.v. administrations of low-osmolality nonionic iodinated contrast material were performed. Acute allergic-like reactions to the contrast material were documented in 20 (0.18%) of the patients. Sixteen (80%) of the acute allergic-like reactions were categorized as mild, one (5%) as moderate, and three (15%) as severe. No deaths were attributed to i.v. nonionic iodinated contrast material. Six (30%) of the patients had a history of allergic-like reaction, including two patients who had a history of reaction to iodinated contrast material. Five (25%) of the patients had a history of asthma., Conclusion: Acute allergic-like reactions to i.v. administration of low-osmolality nonionic iodinated contrast material in children are rare. As in the adult population, most pediatric reactions are mild; however, severe reactions do occur.

Many conditions seen by urologists require imaging examinations with iodinated radiographic contrast material as a key part of the primary evaluation of the patient. A basic understanding of contrast media, risks of administration, choice of agents, and premedication regimens for high-risk patients, is beneficial in helping patients prepare for their examinations. Urologists may be the primary physicians administering contrast material or may be working with radiologists in the care of patients receiving contrast agents. Because contrast reactions may occur unexpectedly, even during examinations in which the agents are not given intravenously, urologists should be able to recognize and treat the various types of adverse reactions.

Prompt recognition and treatment can be invaluable in blunting an adverse response of a patient to radiographic contrast material and may prevent a reaction from becoming severe or even life-threatening. Radiologists and their staff should review treatment procedures regularly (at least annually) so that each staff in attendance can accomplish his or her role efficiently. Knowledge, training, and preparation are crucial in guaranteeing appropriate and aggressive therapy in the event of an adverse contrast-related event.