Hypersensitivity Reactions to Iodinated Contrast Media: A Multicenter Study of 196 081 Patients

Value of orthogonal axial MR images in preoperative T staging of gastric cancer

PURPOSE

To assess the value of orthogonal axial images (OAI) of MRI in gastric cancer T staging.

METHODS

This retrospective study enrolled 133 patients (median age, 63 [range, 24-85] years) with gastric adenocarcinoma who underwent both CT and MRI followed by surgery. MRI lacking or incorporating OAI and CT images were evaluated, respectively. Diagnostic performance (accuracy, sensitivity, and specificity) for each T stage, overall diagnostic accuracy and rates of over- and understaging were quantified employing pathological T stage as a reference standard. The McNemar's test was performed to compare the overall accuracy.

RESULTS

Among patients with pT1-pT4 disease, MRI with OAI (accuracy: 88.7-94.7%, sensitivity: 66.7-93.0%, specificity: 91.5-100.0%) exhibited superior diagnostic performance compared to MRI without OAI (accuracy: 81.2-88.7%, sensitivity: 46.2-83.1%, specificity: 85.5-99.1%) and CT (accuracy: 88.0-92.5%, sensitivity: 53.3-90.1%, specificity: 88.7-98.1%). The overall accuracy of MRI with OAI was significantly higher (83.5%) than that of MRI without OAI (67.7%) (p < .001). However, there was no significant difference in the overall accuracy of MRI with OAI and CT (78.9%) (p = .35). The over- and understaging rates of MRI with OAI (12.0, 4.5%) were lower than those of MRI without OAI (21.8, 10.5%) and CT (12.8, 8.3%).

CONCLUSION

OAI play a pivotal role in the T staging of gastric cancer. MRI incorporating OAI demonstrated commendable performance for gastric cancer T-staging, with a slight tendency toward its superiority over CT.

N-(2,3-dihydroxypropyl) carbamoyl side chain: a potentially significant factor for recurrent iodinated contrast medium-related adverse drug reactions

PURPOSE

To determine whether switching to contrast media based on the sharing of N-(2,3-dihydroxypropyl) carbamoyl side chain reduces the recurrence of iodinated contrast media (ICM)-associated adverse drug reactions (ADRs).

MATERIALS AND METHODS

This single-center retrospective study included 2133 consecutive patients (mean age ± SD, 56.1 ± 11.4 years; male, 1052 [49.3%]) who had a history of ICM-associated ADRs and underwent contrast-enhanced CT examinations. The per-patient and per-exam-based recurrence ADR rates were compared between cases of switching and non-switching the ICM from ICMs that caused the previous ADRs, and between cases that used ICMs with common and different carbamoyl side chains from ICMs that caused the previous ADRs. Downgrade rates (no recurrence or the occurrence of ADR less severe than index ADRs) were also compared. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analysis were additionally performed.

RESULTS

In per-patient analysis, switching of ICM showed a lower recurrence rate (switching, 10.4% [100/965] vs. non-switching, 28.4% [332/1168]), with the adjusted odds ratio (OR) of 0.27 (95% CI: 0.21, 0.34; p < 0.001). The result was consistent in PSM (OR, 0.29 [95% CI: 0.22, 0.39]; p < 0.001), IPTW (OR, 0.28 [95% CI: 0.22, 0.36]; p < 0.001), and in per-exam analysis (5.5% vs. 13.8%; OR, 0.32 [95% CI: 0.27, 0.37]; p < 0.001). There was lower per-exam recurrence (5.0% [195/3938] vs. 7.8% [79/1017]; OR, 0.63 [95% CI: 0.47, 0.83]; p = 0.001) and higher downgrade rates (95.6% [3764/3938] vs. 93.3% [949/1017]; OR, 1.51 [95% CI: 1.12, 2.03]; p = 0.006) when using different side chain groups.

CONCLUSION

Switching to an ICM with a different carbamoyl side chain reduced the recurrent ADRs and their severity during subsequent examinations.

CLINICAL RELEVANCE STATEMENT

Switching to an iodinated contrast media with a different carbamoyl side chain reduced the recurrent adverse drug reactions and their severity during subsequent examinations.

Update on Gadolinium-Based Contrast Agent Safety, From the AJR Special Series on Contrast Media

Since its introduction more than 35 years ago, gadolinium-enhanced MRI has fundamentally changed medical practice. Although extraordinarily safe, gadolinium-based contrast agents (GBCAs) may have side effects. Four distinct safety considerations include acute allergiclike reactions, nephrogenic systemic fibrosis (NSF), gadolinium deposition, and symptoms associated with gadolinium exposure. Acute reactions after GBCA administration are uncommon-far less than with iodinated contrast agents-and, although rare, serious reactions can occur. NSF is a rare but serious sclerodermalike condition occurring in patients with kidney failure after exposure to American College of Radiology (ACR) group I GBCAs. Group II and III GBCAs are considered lower risk, and, through their use, NSF has largely been eliminated. Unrelated to NSF, retention of trace amounts of gadolinium in the brain and other organs has been recognized for over a decade. Deposition occurs with all agents, although linear agents appear to deposit more than macrocyclic agents. Importantly, to date, no data show any adverse biologic or clinical effects from gadolinium deposition, even with normal kidney function. This article summarizes the latest safety evidence of commercially available GBCAs with a focus on new agents, discusses updates to the ACR NSF GBCA safety classifications, and describes approaches for strengthening the evidence needed for regulatory decisions.

The Effect of Iodinated Contrast Media Sensitivity on the Prognosis of Patients with STEMI

Background and Objectives: Iodinated Contrast Media (ICM) is used daily in many imaging departments worldwide. The main risk associated with ICM is hypersensitivity. When a severe hypersensitivity reaction is not properly managed and treated swiftly, it may be fatal. Currently, there is no data to demonstrate how ICM sensitivity affects the prognosis of cardiac patients, especially those diagnosed with ST elevation myocardial infarction (STEMI), in whom urgent coronary angiography is indicated. This study aimed to identify and characterize this relationship. Materials and Methods: We included patients hospitalized with STEMI between 2016 and 2019 from the National Inpatient Sample. The population was compared based on ICM sensitivity status, sensitive vs. non-sensitive. The primary endpoint was in-hospital mortality, with additional endpoints: length of stay and in-hospital complications. Results: The study included 664,620 STEMI patients, of whom 4905 (0.7%) were diagnosed with ICM sensitivity. ICM-sensitive patients were older, more often white, females, and had more comorbidities and cardiovascular risk factors. Both groups show similarities in management but are slightly less probable to undergo PCI or CABG. Multivariable logistic regression models found that the ICM-sensitive population had similar odds of in-hospital mortality (OR: 1.02, 95% CI: 0.89-1.16) and MACCE (OR: 1.05, 95% CI: 0.95-1.16), and less major bleeding (OR: 0.73, 95% CI: 0.60-0.87). Conclusions: Our study found that ICM sensitivity status was not a significant factor for worse prognosis in patients hospitalized with STEMI.

Analysis of Allergy and Hypersensitivity Reactions to COVID-19 Vaccines According to the EudraVigilance Database

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic presented a new challenge in modern medicine: the development of vaccines was followed by massive population vaccinations. A few reports on post-vaccination allergic reactions have made patients and medical personnel uneasy as to COVID-19 vaccines' allergic potential. Most of the studies in this area to date have been small, and some that were based on global databases skipped most of the allergic diseases and concentrated only on anaphylaxis. We aimed to analyze the incidence of serious allergic reactions based on the EudraVigilance (EV) database, regardless of the reported symptoms and allergy mechanism.

METHODS

The total number of administrated vaccine doses was extracted on 5 October 2023 from Vaccine Tracker and included all administrations since vaccinations began in the European Economic Area (EEA). Data on serious allergic reactions to COVID-19 vaccines were extracted from the EudraVigilance database with the same time point. The code names of 147 allergic symptoms or diseases were used.

RESULTS

The frequency of serious allergic reactions per 100,000 administered vaccine doses was 1.53 for Comirnaty, 2.16 for Spikevax, 88.6 for Vaxzevria, 2.11 for Janssen, 7.9 for Novavax, 13.3 for VidPrevtyn Beta, and 3.1 for Valneva. The most prevalent reported reactions were edema (0.46) and anaphylaxis (0.40). Only 6% of these reactions were delayed hypersensitivity-oriented.

CONCLUSIONS

The overall frequency of potential serious allergic reactions to COVID-19 is very rare. Therefore, COVID-19 vaccines seem to be safe for human use. The lowest frequency of allergic reaction was observed for Comirnaty and the highest for Vaxzevria.

Adverse reactions after intravascular iodinated contrast media administration and their management

Endovascular interventions and diagnostic examinations using iodinated contrast media (ICM) are standard of care in current vascular medicine. Although ICM use is generally considered safe, it may be associated with adverse reactions, vary from minor disturbances to rare, but severe life-threatening complications. This position paper of European Society of Vascular Medicine integrates current knowledge and summarizes the key information related to the use of intravascular ICM, serving as recommendation on prevention and management of acute, late, and very late adverse reactions. It should help the health professionals in all fields of vascular medicine to make decisions in daily practice for safe use of contrast media.

Role of Computed Tomography in Cardiac Electrophysiology

With the increasing prevalence of arrhythmias, the use of electrophysiology (EP) procedures has increased. Recent advancements in computed tomography (CT) technology have expanded its use in pre-assessments and post-assessments of EP procedures. CT provides high-resolution images, is noninvasive, and is widely available. This article highlights the strengths and weaknesses of cardiac CT in EP.

How to Define and Manage Low-Risk Drug Allergy Labels

Risk stratification in drug allergy implies that specific risk categories (eg, low, moderate, and high) classify historical drug hypersensitivity reactions. These risk categories can be based on reaction phenotypic characteristics, the timing of the reaction and evaluation, the required reaction management, and individual characteristics. Although a multitude of frameworks have been described in the literature, particularly for penicillin allergy labels, there has yet to be a global consensus, and approaches continue to vary between allergy centers. Immune-mediated drug allergies can sometimes be confirmed using skin testing, but a negative drug challenge is required to demonstrate tolerance and remove the allergy from the electronic health record ("delabel" the allergy). Even for quintessential IgE-mediated drug allergy, penicillin allergy, recent data reveal that a direct oral challenge, without prior skin testing, is an appropriate diagnostic strategy in those who are considered low-risk. Drug allergy pathogenesis and clinical manifestations may vary depending on the culprit drug, and as such, the optimal approach should be based on risk stratification that considers individual patient and reaction characteristics, the likely hypersensitivity reaction phenotype, the drug class, and the patient's clinical needs. This article will describe low-risk drug allergy labels, focusing on β-lactam and sulfonamide antibiotics, nonsteroidal anti-inflammatory drugs, iodinated contrast media, and common chemotherapeutics. This review will also address practical management approaches using currently available risk stratification and clinical decision tools.

Detection of iodixanol-induced allergic reaction signals in Chinese inpatients: a multi-center retrospective database study using prescription sequence symmetry analysis

Objective

This study aimed to explore the signal detection method for allergic reactions induced by inpatient iodixanol injection.

Methods

A database of 3,719,217 hospitalized patients from 20 large Chinese general hospitals was processed and analyzed using the prescription sequence symmetry analysis (PSSA) method.

Results

126,680 inpatients who used iodixanol and were concurrently treated with anti-allergic drugs were analyzed. In the medical records of these patients, only 32 had documented iodixanol allergies. Statistical analysis identified 22 drugs in 4 categories-calcium preparations, adrenergic/dopaminergic agents, glucocorticoids, and antihistamines-as marker drugs. With time intervals of 3, 7, and 28 days, the adjusted sequence ratios (aSRs) for all anti-allergics and the 4 categories were greater than 1. The 7-day aSRs were 2.12 (95% CI: 2.08-2.15), 1.70 (95% CI: 1.68-1.73), 3.85 (95% confidence interval [CI]: 3.75-2.30), 2.30 (95% CI: 2.26-2.35), and 1.95 (95% CI: 1.89-2.02), respectively. The proportions of adverse drug events indicated by each signal were as follows: all anti-allergics (2.92%-3%), calcium gluconate (0.19%-0.52%), adrenergic/dopaminergic agents (2.20%-3.37%), glucocorticoids (3.13%-3.76%), and antihistamines (1.05%-1.32%).

Conclusion

This first multi-center Chinese inpatient database study detected iodixanol-induced allergy signals, revealing that reactions may be much higher than those in collected spontaneous reports. Iodixanol risk exposure was closer to actual pharmaceutical care findings. PSSA application with ≤7-day intervals appears better suited for monitoring late allergic reaction signals with these drugs.

A retrospective study on adverse events of intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications in 83,778 patients

OBJECTIVES

To investigate the rate of adverse events (AEs) caused by intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications retrospectively and to explore practical measures for prevention and treatment of them.

MATERIALS AND METHODS

This study enrolled 83,778 contrast-enhanced ultrasound (CEUS) examinations using sulfur hexafluoride microbubbles intravenously performed during 11 years. Age, gender, and target organs of all CEUS patients were recorded. For cases of AEs, their medical history and laboratory results were also collected. The process of AEs was assessed and categorized. Besides, the management of AEs were recorded.

RESULTS

Twenty patients had sulfur hexafluoride microbubbles-related AEs. The AE rate was 0.024%. No significant difference was observed between patients with AEs and the whole group for age and sex distribution. All AEs happened in liver examinations. Among them, 7 (35%) were mild, 8 (40%) were moderate, and 5 (25%) were severe. They were categorized into 15 allergic-like reactions and 5 physiologic reactions. The manifestations of mild and moderate AEs mainly include urticaria, chills, and mild hypoxia, which could be eased by simple management. Severe cases had anaphylactic shock, generalized convulsions, and diffuse erythema with hypotension respectively. They need close monitoring and oxygen inhalation with anti-shock and anti-anaphylactic treatment. Most cases started within 30 min and recovered within 1 day.

CONCLUSIONS

Intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications was safe with rare AEs. AEs were more likely to happen in abdominal applications than superficial ones. A well-designed emergency plan should be available for clinical use of sulfur hexafluoride microbubbles to reduce AEs and to deal with AEs properly.

CRITICAL RELEVANCE STATEMENT

Intravenous administration of sulfur hexafluoride microbubbles in abdominal and superficial applications reported few AEs and could be considered safe but severe AEs are life-threatening. We analyzed the influence factors of AEs and propose some methods for prevention and treatment of them, which can further improve the safety of sulfur hexafluoride microbubbles in clinical practice.

KEY POINTS

• The AE rate of sulfur hexafluoride microbubbles in abdominal and superficial applications was 0.024%. • Patients were more likely to have AEs in abdominal applications than superficial ones. • Severe AEs are life-threatening and need prompt identification and treatment. • We summarized some detailed suggestions for clinical prevention and treatment of AEs.

Monolacunary Wells-Dawson Polyoxometalate as a Novel Contrast Agent for Computed Tomography: A Comprehensive Study on In Vivo Toxicity and Biodistribution

Polyoxotungstate nanoclusters have recently emerged as promising contrast agents for computed tomography (CT). In order to evaluate their clinical potential, in this study, we evaluated the in vitro CT imaging properties, potential toxic effects in vivo, and tissue distribution of monolacunary Wells-Dawson polyoxometalate, α2-K10P2W17O61.20H2O (mono-WD POM). Mono-WD POM showed superior X-ray attenuation compared to other tungsten-containing nanoclusters (its parent WD-POM and Keggin POM) and the standard iodine-based contrast agent (iohexol). The calculated X-ray attenuation linear slope for mono-WD POM was significantly higher compared to parent WD-POM, Keggin POM, and iohexol (5.97 ± 0.14 vs. 4.84 ± 0.05, 4.55 ± 0.16, and 4.30 ± 0.09, respectively). Acute oral (maximum-administered dose (MAD) = 960 mg/kg) and intravenous administration (1/10, 1/5, and 1/3 MAD) of mono-WD POM did not induce unexpected changes in rats' general habits or mortality. Results of blood gas analysis, CO-oximetry status, and the levels of electrolytes, glucose, lactate, creatinine, and BUN demonstrated a dose-dependent tendency 14 days after intravenous administration of mono-WD POM. The most significant differences compared to the control were observed for 1/3 MAD, being approximately seventy times higher than the typically used dose (0.015 mmol W/kg) of tungsten-based contrast agents. The highest tungsten deposition was found in the kidney (1/3 MAD-0.67 ± 0.12; 1/5 MAD-0.59 ± 0.07; 1/10 MAD-0.54 ± 0.05), which corresponded to detected morphological irregularities, electrolyte imbalance, and increased BUN levels.

Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Incidence of Bowel Wall Swelling Induced by Iodine-Contrast Media and Its Association With Gastrointestinal Manifestation

PURPOSE

The aim of this study was to investigate the incidence of bowel wall swelling after iodine-contrast media injection and its relationship with gastrointestinal symptoms.

METHODS

The incidence of bowel wall swelling was examined in 75 patients who showed adverse reactions to iodine-contrast media (AR[+] group) and 75 controls without adverse reactions (AR[-] group). Bowel wall swelling was identified if there was increased wall thickness on postcontrast computed tomography when compared with precontrast computed tomography. Swelling less than 2-fold of the original wall thickness was defined as grade 1 bowel angioedema, and swelling more than 2-fold was defined as grade 2.

RESULTS

The incidence of bowel wall swelling was significantly higher in the AR(+) group (26.6%) than in the AR(-) group (10.6%) ( P = 0.01). Grade 1 bowel wall swelling was observed in 12.0% and 10.7% of AR(+) and AR(-) groups, respectively, whereas grade 2 was observed in 14.7% and 0%, respectively. Bowel wall swelling was observed in the duodenum and jejunum but not in the stomach, ileum, or colon in any patient in either group. In the AR(+) group, nausea and/or vomiting was observed in 15 patients, among whom bowel wall swelling was observed in 9 patients (60%). The frequency of nausea and/or vomiting was significantly higher in the patients with bowel wall swelling (45.0%, 9/20) compared with those without (10.9%, 6/55).

CONCLUSION

Bowel wall swelling was more frequent and severe in patients with adverse reactions to iodine-contrast media than those without and was associated with nausea and/or vomiting.

Acute Adverse Events After Iodinated Contrast Agent Administration of 359,977 Injections: A Single-Center Retrospective Study

OBJECTIVE

To assess the effects of patient variables, examination variables, and seasonality on allergic-like and physiologic reactions to iodinated contrast material (ICM).

PATIENTS AND METHODS

All ICM-enhanced computed tomography (CT) examinations performed from June 1, 2009, to May 9, 2017, at our institution were included. Reactions were identified and categorized as allergic-like or physiologic and mild, moderate, or severe. The effect of patient and examination variables on reactions was evaluated by logistic regression models.

RESULTS

A total of 359,977 CT examinations performed on 176,886 unique patients were included. A total of 1150 allergic-like reactions (0.32%; 19 severe [0.005%]) and 679 physiologic reactions (0.19%; 3 severe [0.0008%]) occurred. On multivariable analysis, iopromide had higher rates of reactions compared with iohexol (allergic-like reactions: odds ratio [OR], 3.07 [95% CI, 2.37 to 3.98], P<.0001; physiologic reactions: OR, 2.60 [1.92 to 3.52], P<.0001). Non-White patients had higher rates of reactions compared with White patients (allergic-like reactions: OR, 1.77 [1.36-2.30], P<.0001; physiologic reactions: OR, 1.76 [1.27-2.42], P=.0006). Patient age, sex, prior ICM reaction, ICM dose, CT location, and CT type were also significantly associated with reactions. No significant seasonality trend was observed (P=.07 and .80).

CONCLUSION

Non-White patients and patients administered iopromide had higher rates of acute reactions compared with White patients and patients administered iohexol. Younger patients (<50 years vs 51 to 60 years), female sex, history of ICM allergy or other allergies, ICM dose, and contrast-enhanced CT location and type also correlated with higher acute reaction rates.

Hidden risk of gadolinium-based contrast agents during interventional pain medicine procedures: a retrospective chart review

INTRODUCTION

Epidural steroid injections and epidural blood patches commonly involve the injection of a small amount of radiocontrast media under fluoroscopy to properly identify the target tissue or anatomic space and prevent off-target or intravascular delivery of therapeutic or diagnostic drugs. Iodinated low osmolar non-ionic contrast media is the standard preparation used as it is considered safe and cost-effective, but gadolinium-based preparations have been used as an alternative for patients with an 'iodine'-related or radiocontrast media allergy label to prevent hypersensitivity reactions. The risk of neurotoxic events when gadolinium is inadvertently injected into the intrathecal space has been reported in recent years, raising concerns when gadolinium-based contrast media is used in lieu of iodinated low osmolar non-ionic contrast media.

METHODS

A retrospective review was conducted of patients who received gadolinium-based contrast media for procedures with risk of inadvertent intrathecal access from January 1, 2019 to May 1, 2022. Information on patient demographics, allergy label information, and procedure description was documented for all patients who received gadolinium-based contrast media for axial spine procedures (including epidural steroid injections, epidural blood patch procedures, and selective nerve root blocks), and all side effects reported within 1 month of the procedure were recorded. Saved fluoroscopy images of all procedures for which there was concern for possible gadolinium-based contrast media-related side effect were reviewed for evidence of inadvertent intrathecal gadolinium-based contrast media administration. Descriptive statistical analysis was performed using REDCap and IBM SPSS Statistics V.28.

RESULTS

We identified 508 patients who received gadolinium-based contrast media during a fluoroscopically guided axial spine procedure. These patients underwent 697 epidural procedures and 23 patients were identified as experiencing an adverse event that could be consistent with possible, probable, or clear signs of exposure to intrathecal gadolinium. Our calculated adverse event rate was 3.3%. Ten patients required additional medical evaluation or treatment.

DISCUSSION

Almost all patients in our cohort had an allergy label on their chart that guided the provider to switch to gadolinium-based contrast media, but most were incomplete, ill-defined, or related to allergy to iodine but not iodinated contrast media. Such practice is not recommended based on current guidelines. The current study raises concern regarding the use of gadolinium-based contrast media in axial spine procedures, with the risk of potential severe adverse events, without evidence-based need for avoiding iodinated contrast media.

Pulmonary embolism diagnostic strategies in patients with COPD exacerbation: Post-hoc analysis of the PEP trial

BACKGROUND

The prevalence of pulmonary embolism (PE) is approximately 11-17 % in patients with an acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). The optimal diagnostic strategy for PE in these patients remains undetermined.

AIMS

To evaluate the safety and efficacy of standard (revised Geneva and Wells PE scores combined with fixed D-dimer cut-off) and computed tomography pulmonary angiogram (CTPA)-sparing diagnostic strategies (ADJUST-PE, YEARS, PEGeD, 4PEPS) in patients with AE-COPD.

METHOD

Post-hoc analyses of data from the multicenter prospective PEP study were performed. The primary outcome was the diagnostic failure rate of venous thromboembolism (VTE) during the entire study period. Secondary outcomes included diagnostic failure rate of PE and deep venous thrombosis (DVT), respectively, during the entire study period and the number of CTPA needed per diagnostic strategy.

RESULTS

740 patients were included. The revised Geneva and Wells PE scores combined with fixed D-dimer cut-off had a diagnostic failure rate of VTE of 0.7 % (95%CI 0.3 %-1.7 %), but >70.0 % of the patients needed imaging. All CTPA-sparing diagnostic algorithms reduced the need for CTPAs (-10.1 % to -32.4 %, depending on the algorithm), at the cost of an increased VTE diagnosis failure rate of up to 2.1 % (95%CI 1.2 %-3.4 %).

CONCLUSION

Revised Geneva and Wells PE scores combined with fixed D-dimer cut-off were safe, but a high number of CTPA remained needed. CTPA-sparing algorithms would reduce imaging, at the cost of an increased VTE diagnosis failure rate that exceeds the safety threshold. Further studies are needed to improve diagnostic management in this population.

Utility of Carbon Dioxide Venography and Intraprocedural CT for Adrenal Venous Sampling in Patients with an Allergy to Iodinated Contrast Media

PURPOSE

To assess the diagnostic performance of carbon dioxide (CO2) and intraprocedural unenhanced computed tomography (CT) for adrenal venous sampling (AVS) (CO2-intraprocedural unenhanced CT-AVS) in patients with primary aldosteronism (PA) and a history of iodine contrast medium allergy.

MATERIALS AND METHODS

CO2-intraprocedural unenhanced CT-AVS was performed in 18 patients with iodine contrast media allergies at the authors' hospital between December 2015 and January 2021. CT and noncontrast magnetic resonance angiography were used to evaluate the preoperative adrenal vein anatomy. CO2 venography was performed to confirm adrenal vein catheterization. Additionally, intraprocedural unenhanced CT was also performed to confirm catheter position in the right adrenal gland.

RESULTS

In all cases in which CO2-intraprocedural unenhanced CT-AVS was performed, the right and left adrenal veins were catheterized appropriately, leading to a localized diagnosis. Catheterization of the left adrenal vein was confirmed using CO2 venography in all cases. In 7 of the 18 cases, CO2 venography demonstrated selection of the right adrenal vein. In 15 of 18 cases, intraprocedural unenhanced CT demonstrated selection of the right adrenal vein.

CONCLUSIONS

CO2-intraprocedural unenhanced CT-AVS demonstrated the same diagnostic ability for PA localization as conventional AVS with iodine contrast media. The proposed method is clinically feasible for AVS, in which iodine contrast media use is restricted.

Preventing post-contrast acute kidney injury and hypersensitivity reactions: UK national audit

AIM

To audit UK radiology departmental protocols related to the prevention of Iodine-based contrast media (ICM) adverse drug reactions (ADRs) and to assess their compliance with the Royal College of Radiologists (RCR) endorsed Royal Australian and New Zealand College of Radiologists' 2018 Iodinated Contrast Guidelines.

MATERIALS AND METHODS

Questionnaires were sent to all UK acute National Health Service (NHS) providers treating adult patients with an audit lead registered with the RCR (162 providers encompassing 211 hospital radiology departments). The questionnaire included three main sections: renal function screening, renal protection regimens, and hypersensitivity reactions prevention and follow-up. Data collection was conducted between April and July 2022.

RESULTS

Sixty-one per cent (129/211) of departments responded, representing 67% of eligible providers. An independent imaging services provider supplied one additional set of data (n=130 overall). Of the responding departments, for post-contrast acute kidney injury (PC-AKI), 41% and 56% had the recommended risk assessment for inpatients and outpatients, respectively. Renal function testing was often over-utilised, and their results were applied improperly. Sixty-eight per cent of departments used the advised threshold for considering renal protection. For hypersensitivity reactions, 9% of departments had the correct risk assessment. Thirty-six per cent of departments had the correct risk mitigation protocol for identified high-risk patients. The documentation and follow-up for hypersensitivity reactions were similarly inadequate.

CONCLUSION

Local protocols on preventing ICM ADRs were largely non-compliant with RCR guidelines. Departments need to update their protocols in line with current evidence to avoid iatrogenic morbidity or unnecessary tests and over-precaution.

Simulation Training in the Management of Adverse Contrast Reactions: A Systematic Review

BACKGROUND

Simulation-based training has become increasingly prominent within medical education, but its utility within radiology remains underexplored.

OBJECTIVE

To appraise the evidence for the effectiveness of simulation on the management of adverse reactions to contrast media.

METHODS

A systematic search of the literature was conducted. Eligible studies recruited radiology residents, provided simulation-based training focused on contrast reaction management, and measured any effectiveness outcome compared with any nonsimulation training or no training. The quality of studies was appraised and outcomes were classified according to Kirkpatrick's hierarchy and the strength of evidence.

RESULTS

Out of 146 screened results, 15 articles were included that described 17 studies-3 randomized trials and 14 pretest-posttest studies of hands-on or, less commonly, computer-based simulation. In all 16 studies that assessed knowledge before and after intervention, written test scores improved after simulation. Most studies noted improvements in comfort or confidence managing contrast reactions as well. In all three studies that assessed knowledge after simulation and after didactic lecture as a control, posttest scores were not statistically significantly better in the simulation groups than the lecture groups. Common study limitations included single-group designs, measuring only learning outcomes using unvalidated instruments, modest sample sizes, and limited assessment of long-term retention.

CONCLUSION

Simulation produces subjective improvements and knowledge gain relevant to contrast reaction management. Further research is required to demonstrate superiority of simulation-based contrast reaction management training over traditional didactic lecture-based instruction.

Enhanced CT combined with texture analysis for differential diagnosis of pleomorphic adenoma and adenolymphoma

OBJECTIVE

This study sought to evaluate the worth of the general characteristics of enhanced CT images and the histogram parameters of each stage in distinguishing pleomorphic adenoma (PA) and adenolymphoma (AL).

METHODS

The imaging features and histogram parameters of preoperative enhanced CT images in 20 patients with PA and 29 patients with AL were analyzed. Tumor morphology and histogram parameters of PA and AL were compared. Area under the curve (AUC), sensitivity, and subject operational feature specificity (ROC) analysis were used to determine the differential diagnostic effect of single-stage or multi-stage parameter combinations.

RESULTS

The difference in CT value and net enhancement value of arterial phase (AP) were significant (p < 0.05); Flat sweep phase (FSP), AP mean, percentiles, 10th, 50th, 90th, 99th and arterial period variance and venous phase (VP) kurtosis in the nine histogram parameters of each period (p < 0.05). An analysis of the ROC curve revealed a maximum area beneath the curve (AUC) in the 90th percentile of FSP for a single-parameter differential diagnosis to be 0.870. The diagnostic efficacy of the mean value of FSP + The 90th percentile of AP + Kurtosis of VP was the best in multi-parameter combination diagnosis, with an AUC of 0.925, and the sensitivity and specificity of 0.900 and 0.850, respectively.

CONCLUSION

The histogram analysis of enhanced CT images is valuable for the differentiation of PA and AL. Moreover, the combination of single-stage parameters or multi-stage parameters can improve the differential diagnosis efficiency.

Substitution with Low-Osmolar Iodinated Contrast Agent to Minimize Recurrent Immediate Hypersensitivity Reaction

Background The recurrence of hypersensitivity reaction (HSR) to low-osmolar iodinated contrast media (LOCM) remains challenging despite premedication and substitution of the LOCM. Purpose To determine the optimal practical preventive strategy for LOCM substitution in patients with a history of prior immediate HSR to LOCM. Materials and Methods In a retrospective study, patients with an immediate HSR to LOCM before February 2020 and who underwent subsequent exposure to LOCM until March 2021 were enrolled in five tertiary referral hospitals in South Korea. The association of recurrence of an HSR after subsequent LOCM exposures was assessed using multivariate general estimating equation analysis according to age, sex, the severity of the index HSR, premedication, and substituting LOCM based on common carbamoyl side chains, including the N-(2,3-dihydroxypropyl)-carbamoyl and N-(2,3-dihydroxypropyl)-N-methyl-carbamoyl moieties. Results The evaluation included 3800 subsequent LOCM exposures in 1066 patients (mean age, 56.2 years ± 13.5 [SD]; 567 [53%] female and 499 [47%] male patients). The general estimating equation analysis, using 1:1 propensity score matched data for age, sex, HSR severity, and LOCM selection, showed that premedication with corticosteroids significantly reduced recurrent HSR (odds ratio [OR], 0.72; 95% CI: 0.52, 1.00; P = .049). The change to another LOCM with a common side chain had a similar recurrence rate as using the same LOCM (OR, 0.98; 95% CI: 0.64, 1.50; P = .93), whereas the use of a different LOCM without a common side chain significantly lowered HSR recurrence (OR, 0.51; 95% CI: 0.37, 0.69; P < .001) in multivariate general estimating equation analysis. Substitution of an LOCM without a common side chain was effective regardless of the index HSR severity but was more pronounced in moderate-to-severe reactions (OR, 0.30; 95% CI: 0.16, 0.55; P < .001). Conclusion For patients with a previous immediate HSR of any severity to LOCM, alternative LOCM without a common carbamoyl side chain reduced recurrent HSR during subsequent exposures. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by McDonald in this issue.

Late adverse events to iodinated contrast media in patients treated with IL-2: a safety report from the Danish Renal Carcinoma Group (DaRenCa) study - 1

BACKGROUND

A higher incidence of late adverse events (LAEs) to iodinated contrast media in interleukin-2 (IL-2)-treated patients has been reported.

PURPOSE

To assess the incidence of LAEs after administration of iodinated contrast media in patients with metastatic renal cell carcinoma (mRCC) treated with IL-2.

MATERIAL AND METHODS

Patients were randomized to treatment with IL-2 and interferon-α with/without bevacizumab in the Danish Renal Carcinoma Group study - 1. Patients underwent a computed tomography (CT) scan at baseline, at one month, at three months, and every third month until RECIST 1.1 defined progression. LAEs due to iodinated contrast media were systematically registered according to the Common Terminology Criteria for Adverse Events classification.

RESULTS

In total, 89 patients were included and underwent a total of 507 contrast-enhanced CT scans. An overall incidence of 46 (9.1%) LAEs was observed in 38 of 89 (42.7%) patients; 3 LAEs at baseline (3.4% of all baseline scans), 39 (13.9%) LAEs during IL-2-based therapies, and 4 (2.9%) LAEs after termination of IL-based therapies. There was no difference in progression-free survival, overall survival, and treatment response in patients experiencing LAEs compared to patients without LAEs (P = 0.2, P = 0.5, and P = 0.6, respectively).

CONCLUSION

Patients with mRCC demonstrated a higher incidence of LAEs after administration of iodinated contrast during ongoing IL-2 therapy, indicating that iodinated contrast media may cause a recall phenomenon of IL-2 toxicities in patients with mRCC. Treatment with IL-2 should not be a contraindication for contrast-enhanced scans in patients with mRCC but expertise and vigilance are required.

Exploring Factors Affecting the Occurrence of Hypersensitivity Reactions Induced by Nonionic Iodine Contrast Media

Hypersensitivity reactions induced by nonionic iodine contrast media sometimes occur and can be life threatening. However, independent factors affecting their occurrence remain to be fully established. Therefore, the purpose of this study was to clarify independent factors affecting the occurrence of hypersensitivity reactions induced by nonionic iodine contrast media. Patients who received nonionic iodine contrast media at Keiyu Hospital from April 2014 to December 2019 were included. The adjusted odds ratio (OR) and 95% confidence interval (CI) for factors affecting hypersensitivity reactions induced by contrast media were calculated by logistic regression analysis. The multiple imputation method was used to impute missing data. Hypersensitivity reactions occurred in 0.72% (163 cases) of 22,695 cases enrolled in this study. In univariate analysis, 10 variables met the criteria of P < .05 and proportion of missing data <50%. In multivariate analysis, age (OR, 0.98; 95% CI, 0.97-0.99), outpatient status (OR, 2.08; 95% CI, 1.20-3.60), contrast medium iodine content (OR, 1.02; 95% CI, 1.01-1.04), history of drug allergy (OR, 2.41; 95% CI, 1.50-3.88), and asthma (OR, 17.4; 95% CI, 7.53-40.1) were identified as independent factors affecting contrast media-induced hypersensitivity reactions. Among these factors, history of drug allergy and asthma appear to be clinically relevant and reliable due to their high OR and plausible biological mechanisms, but the other three factors require further validation.

Sex differences in guideline-consistent diagnostic testing for acute pulmonary embolism among adult emergency department patients aged 18-49

BACKGROUND

Pulmonary embolism (PE) is a frequent diagnostic consideration in emergency department (ED) patients, yet diagnosis is challenging because symptoms of PE are nonspecific. Guidelines recommend the use of clinical decision tools to increase efficiency and avoid harms from overtesting, including D-dimer screening in patients not at high risk for PE. Women undergo testing for PE more often than men yet have a lower yield from testing. Our study objective was to determine whether patient sex influenced the odds of received guideline-consistent care.

METHODS

We performed a retrospective cohort study at two large U.S. academic EDs from January 1, 2016, to December 31, 2018. Nonpregnant patients aged 18-49 years were included if they presented with chest pain, shortness of breath, hemoptysis, or syncope and underwent testing for PE with D-dimer or imaging. Demographic and clinical data were exported from the electronic medical record (EMR). Pretest risk scores were calculated using manually abstracted EMR data. Diagnostic testing was then compared with recommended testing based on pretest risk. The primary outcome was receipt of guideline-consistent care, which required an elevated screening D-dimer prior to imaging in all non-high-risk patients.

RESULTS

We studied 1991 discrete patient encounters; 37% (735) of patients were male and 63% (1256) were female. Baseline characteristics, including revised Geneva scores, were similar between sexes. Female patients were more likely to receive guideline-consistent care (70% [874/1256] female vs. 63% [463/735] male, p < 0.01) and less likely to be diagnosed with PE (3.1% [39/1256] female vs. 5.3% [39/735] male, p < 0.05). The most common guideline deviation in both sexes was obtaining imaging without a screening D-dimer in a non-high-risk patient (75% [287/382] female vs. 75% [205/272] male).

CONCLUSIONS

In this cohort, females were more likely than males to receive care consistent with current guidelines and less likely to be diagnosed with PE.

Clinical features and risk factors of iodinated contrast media (ICM)-induced anaphylaxis

PURPOSE

To evaluate the clinical features and risk factors of iodinated contrast media (ICM)-induced anaphylaxis.

METHODS

This retrospective study included all patients undergoing contrast-enhanced computed tomography (CT) with intravenous ICM administration (iopamidol, iohexol, iomeprol, iopromide, ioversol) at our hospital between April 2016 and September 2021. Medical records of patients who experienced anaphylaxis were reviewed, and the multivariable regression model using generalized estimating equations was employed to eliminate the effect of intrapatient correlation.

RESULTS

Of the 76,194 ICM administrations (44,099 men [58 %] and 32,095 women; age, median, 68 years) to 27, 696 patients, anaphylaxis occurred in 45 cases in 45 different patients (0.06 % of administration and 0.16 % of patients), all with onset within 30 min after administration. Thirty-one (69 %) had no risk factors for ADRs, including 14 (31 %) who had previously used the same ICM that caused anaphylaxis. Thirty-one patients (69 %) had a history of ICM use without any ADRs. Four patients (8.9 %) received oral steroid premedication. The only factor associated with anaphylaxis was the type of ICM, with an odds ratio (OR) of 6.8 (p < 0.001) for iomeprol with iopamidol as a reference. No significant differences in OR of anaphylaxis were found for patients' age, sex, or premedication.

CONCLUSION

The overall incidence of anaphylaxis due to ICM was very low. More than half of the cases had no risk factors for ADRs and had no ADRs on past ICM administration, although the ICM type was associated with a higher OR.

Incidence and severity of nonionic low-osmolar iodinated contrast medium-related adverse drug reactions in the Republic of Korea: Comparison by generic

We aimed to report the incidence and severity of nonionic low-osmolar iodine contrast medium (ICM)-related adverse drug reactions (ADRs) in the Republic of Korea, by analyzing data from our single tertiary institution and published Korean reports, and to determine whether there is a difference in the incidence of ICM-related ADR by ICM generics. A total of 1,161,419 consecutive contrast-enhanced computed tomography (CT) examinations between January 2016 and December 2021 at Asan Medical Center were included. A systematic search of the literature investigating the incidence of ICM-related ADR in the Republic of Korea published up to December 31, 2021 was performed. We pooled these outcomes with those of our study using a binomial-normal model, and the pooled incidences of ADRs were compared among ICM generics using chi-square tests. Seven studies with a total of 2,570,986 contrast-enhanced CT examinations from 12 institutions were included. The pooled incidences of overall, mild, moderate, and severe ICM-related ADRs in the Republic of Korea were 0.82% (95% CI: 0.61%-1.10%), 0.72% (95% CI: 0.50%-1.04%), 0.11% (95% CI: 0.08%-0.15%), and 0.013% (95% CI: 0.010%-0.018%), respectively. In multiple pairwise comparisons, there were no significant differences in the overall incidence of ADRs between ICM generics, except iomeprol versus iobitridol and iomeprol versus iohexol. For moderate and severe ADRs, there were no significant differences in ADR incidence between ICM generics. The incidence of moderate and severe ICM-related ADRs did not differ among ICM generics. Our results suggest that no restriction is required for selection among nonionic low-osmolar ICMs.

Reducing contrast agent residuals in hospital wastewater: the GREENWATER study protocol

The potential enviromental impact of iodinated (ICAs) and gadolinium-based contrast agents (GBCAs) have recently come under scrutiny, considering the current nonselective wastewater treatment. However, their rapid excretion after intravenous administration could allow their potential recovery by targeting hospital sewage. The GREENWATER study aims to appraise the effective quantities of ICAs and GBCAs retrievable from patients' urine collected after computed tomography (CT) and magnetic resonance imaging (MRI) exams, selecting ICA/GBCA per-patient urinary excretion and patients' acceptance rate as study endpoints. Within a prospective, observational, single-centre, 1-year framework, we will enrol outpatients aged ≥ 18 years, scheduled to perform contrast-enhanced CT or MRI, willing to collect post-examination urine in dedicated canisters by prolonging their hospital stay to 1 h after injection. Collected urine will be processed and partially stored in the institutional biobank. Patient-based analysis will be performed for the first 100 CT and 100 MRI patients, and then, all analyses will be conducted on the pooled urinary sample. Quantification of urinary iodine and gadolinium will be performed with spectroscopy after oxidative digestion. The evaluation of the acceptance rate will assess the "environmental awareness" of patients and will aid to model how procedures to reduce ICA/GBCA enviromental impact could be adapted in different settings. Key points • Enviromental impact of iodinated and gadolinium-based contrast agents represents a growing point of attention.• Current wastewater treatment is unable to retrieve and recycle contrast agents.• Prolonging hospital stay may allow contrast agents retrieval from patients' urine.• The GREENWATER study will assess the effectively retrievable contrast agents' quantities.• The enrolment acceptance rate will allow to evaluate patients' "green sensitivity".

Histogram analysis of ultrasonographic images in the differentiation of benign and malignant parotid gland tumors

OBJECTIVE

We evaluated the diagnostic value of histogram analysis (HA) using ultrasonographic (US) images for differentiation among pleomorphic adenoma (PA), adenolymphoma (AL), and malignant tumors (MT) of the parotid gland.

STUDY DESIGN

Preoperative US images of 48 patients with PA, 39 patients with AL, and 17 patients with MT were retrospectively analyzed for gray-scale histograms. Nine first-order texture features derived from histograms of the tumors were compared. Area under the receiver operating characteristic curve (AUC) was used to evaluate the diagnostic performance of texture features. The Youden index maximum exponent was used to calculate sensitivity and specificity.

RESULTS

Statistically significant differences were discovered in Mean and Skewness HA values between PA and AL (P<0.001), and in Mean values between AL and MT (P<0.001). However, comparison of PA and MT showed no statistically significant differences (P>0.01). Excellent discrimination was detected between PA and AL (AUC=0.802), and between AL and MT (AUC=0.822). The combination of Mean plus Skewness improved discrimination between PA and AL (AUC=0.823) with sensitivity values reaching 1.00. However, Mean plus Skewness applied to differentiate PA from AL and Mean values applied to distinguish AL and MT resulted in low specificity, indicating many false positive interpretations.

CONCLUSIONS

Histogram analysis is useful for differentiating PA from AL and AL from MT but not PA from MT.

Perfusion-Dependent Focal Neurologic Deficits in a Critically Ill Heart Transplant Recipient: A Case of Tacrolimus-Associated Reversible Cerebral Vasospasm Syndrome?

TACROLIMUS, a mainstay of immunosuppression after orthotopic heart transplantation (OHT), is associated with a broad range of side effects. Vasoconstriction caused by tacrolimus has been proposed as a mechanism underlying common side effects such as hypertension and renal injury. Neurologic side effects attributed to tacrolimus include headaches, posterior reversible encephalopathy syndrome (PRES), or reversible cerebral vasospasm syndrome (RCVS). Six case reports have been published describing RCVS in the setting of tacrolimus administration after OHT. The authors report a case of perfusion-dependent focal neurologic deficits attributed to tacrolimus-induced RCVS in an OHT recipient.

Contrast Agent Selection to Prevent Recurrent Severe Hypersensitivity Reaction to Iodinated Contrast Media Based on Nationwide Database

OBJECTIVE

To investigate the incidence of severe iodinated contrast media (ICM)-related hypersensitivity reaction (HSR) and to find the optimal alternative ICM to reduce the risk of severe HSR recurrence.

METHODS

We retrospectively reviewed 23,383,183 cases of ICM administration between January 2015 and December 2019 from the nationwide health insurance database. We classified ICMs based on generic profiles and the presence of N-(2,3-dihydroxypropyl) carbamoyl side chains. The incidence of severe and recurrent severe HSRs was calculated, and χ2 tests were performed to compare the prevalence of severe HSR according to ICM groups. In addition, logistic regression analyses were used to assess differences between ICM groups.

RESULTS

The incidence of severe HSRs was 1.92% (450,067 of 23,282,183). Among 1,875,245 individuals who received ICM twice on different days, severe HSR occurred in 40,850 individuals, and severe HSR recurred in 3319 individuals (8.12%). The risk of recurrence significantly decreased when the ICM changed (9.24% vs 7.08%, P < 0.001), especially when the ICM changed to one with a different side chain (6.74%, P < 0.001). In addition, compared with the reuse of the culprit agent, using combinations of iobitridol/iohexol (odds ratio [OR], 0.696; P = 0.04), iohexol/iopamidol (OR, 0.757; P = 0.007), iopamidol/iohexol (OR, 0.447; P < 0.001), and ioversol/iohexol (OR, 0.683; P = 0.04) reduced the risk of recurrence of severe HSR.

CONCLUSIONS

Changing the culprit ICM to that with a different side chain can reduce severe HSR recurrence. The optimal choice of an alternative ICM depends on the causative agent.

Time-of-Flight Angiography in Ultra-High-Field 7 T MRI for the Evaluation of Peroneal Perforator Arteries Before Osseomyocutaneous Flap Surgery

OBJECTIVES

Presurgical identification and morphologic characterization of the peroneal perforator arteries (PPAs) are essential for osseomyocutaneous flap surgery. The aim of this study was to evaluate PPAs using time-of-flight (TOF) angiography in 7 T magnetic resonance imaging in comparison with dual-energy computed tomographic angiography (CTA).

MATERIALS AND METHODS

In this prospective study, TOF angiography and CTA of both lower legs were acquired before flap surgery from 07/2019 to 02/2020. Magnetic resonance imaging was performed using a dedicated 28-channel knee coil with an acquisition time of 9:55 minutes (voxel size: 0.4 × 0.4 × 0.8 mm). Computed tomographic angiography was acquired with a third-generation dual-source computed tomography on the same day. Virtual monoenergetic reconstructions at 40 keV photon energy served as the standard of reference for PPA identification and subtyping. Two independent readers assessed the image quality, quantity, length assessment, and classification according to surgical considerations of PPAs for TOF angiography and CTA. Both TOF angiography and CTA were used for presurgical flap design and were evaluated by an orofacial surgeon.

RESULTS

Ten patients (mean age, 59.9 ± 14.9 years; 7 men) were included. Time-of-flight angiography and CTA identified 53 and 51 PPAs in total, respectively. Time-of-flight angiography showed superior image quality (both readers, P < 0.05). Time-of-flight angiography enabled specific classification of PPA subtypes more often (53 vs 39; P < 0.05), and both readers reported higher diagnostic confidence for TOF angiography than CTA in all patients (interrater agreement κ = 0.8; P < 0.05). Regarding length assessment, PPAs were significantly more conspicuous with TOF angiography (TOF mean , 50 ± 11 mm; CTA mean , 40 ± 9 mm; P = 0.001). In comparison with CTA, TOF angiography prospectively changed the orofacial surgeon's final decision on the presurgical selected PPAs in 60% of cases.

CONCLUSIONS

Presurgical assessment of PPAs is feasible using TOF in 7 T magnetic resonance imaging. Moreover, TOF angiography was superior to CTA for classifying and identifying PPAs, which may facilitate the planning of reconstructive surgery.

Safety findings after intravenous administration of sulfur hexafluoride microbubbles to 463,434 examinations at 24 centers

OBJECTIVES

We aimed to evaluate the safety of the ultrasound contrast agent sulfur hexafluoride microbubbles in a large group of patients referred for routine contrast-enhanced ultrasound (CEUS).

METHODS

A retrospective assessment was made of all patients that received sulfur hexafluoride microbubbles intravenously for CEUS at 24 centers between January 2006 and April 2019. Patient demographic details, examination type, and the dose of sulfur hexafluoride microbubbles administered were recorded with specific adverse events (AEs) documentation tools at each center. All AEs were recorded as serious or non-serious. Non-serious AEs were classified by intensity as mild, moderate, or severe according to ACR criteria. The frequencies of AEs across patient subgroups were compared using the chi-square test.

RESULTS

A total of 463,434 examinations were evaluated. Overall, 157 AEs (153 [0.033%] non-serious; 4 [0.001%] serious) were reported after sulfur hexafluoride microbubbles administration, giving an AE frequency of 0.034% (157/463,434). Among the non-serious AEs, 66 (0.014%) were mild, 70 (0.015%) moderate, and 17 (0.004%) severe in intensity. The liver was the most common examination site, presenting an AE frequency of 0.026%. The highest AE frequency (0.092%) was for patients undergoing CEUS for vascular disease. There were no significant gender differences in either the total number or the severity of non-serious AEs (chi-square = 2.497, p = 0.287). The onset of AEs occurred within 30 min of sulfur hexafluoride microbubbles administration in 91% of cases.

CONCLUSION

The frequency of AEs to sulfur hexafluoride microbubbles is very low and severe reactions are rare, confirming that sulfur hexafluoride microbubbles are appropriate for routine CEUS applications.

KEY POINT

• The frequency of AEs to sulfur hexafluoride microbubbles is very low and severe reactions are rare.

German Radiological Society and the Professional Association of German Radiologists Position Paper on Coronary computed tomography: Clinical Evidence and Quality of Patient Care in Chronic Coronary Syndrome

This position paper is a joint statement of the German Radiological Society (DRG) and the Professional Association of German Radiologists (BDR), which reflects the current state of knowledge about coronary computed tomography. It is based on preclinical and clinical studies that have investigated the clinical relevance as well as the technical requirements and fundamentals of cardiac computed tomography. CITATION FORMAT: · Langenbach MC, Sandstede J, Sieren M et al. DRG and BDR Position Paper on Coronary CT: Clinical Evidence and Quality of Patient Care in Chronic Coronary Syndrome. Fortschr Röntgenstr 2023; 195: 115 - 133.

[German Radiological Society and the Professional Association of German Radiologists position paper on coronary computed tomography: clinical evidence and quality of patient care in chronic coronary syndrome]

This position paper is a joint statement of the German Radiological Society (DRG) and the Professional Association of German Radiologists (BDR), which reflects the current state of knowledge about coronary computed tomography (CT). It is based on preclinical and clinical studies that have investigated the clinical relevance as well as the technical requirements and fundamentals of cardiac computed tomography.

Stratified assessment and warning regimen for prevention of acute adverse reactions to iodinated contrast media: results of 150,343 cases in a tertiary hospital

For contrast-enhanced CT examinations, there is a lack of comprehensive optimal management strategies of risk factors to reduce the risk of iodinated contrast media (ICM)-induced acute adverse reactions (AAR). Here, we determine the relationship between the rate of ICM-AAR and a stratified assessment and warning (SAW) regimen, which integrated risk identification, stratification, early warning, and prevention. A total of 120,822 cases in the conventional assessment period (58 years ± 15, 55.25% men) and 150,343 cases (58 years ± 14, 55.83% men) in the SAW period were enrolled. The results showed that the total AAR incidence in the SAW period (414/150,343, 0.28%) was lower than that in the conventional assessment period (506/120,822, 0.42%, P < 0.001), in which the proportion of AAR patients decreased by one-third. It mainly presented as decreases in mild and moderate reactions (P < 0.001), and a decrease in the proportion of moderate AAR patients (P = 0.001). Subgroup analysis showed lower mild and moderate AAR incidence in patients with different risk levels and with different ICM injection parameters following SAW regimen. We concluded that SAW regimen was associated with lower incidence of mild and moderate AAR, and decreased proportion of moderate AAR patients, which held potential for improved ICM safety.

Multiple Adversarial Learning based Angiography Reconstruction for Ultra-low-dose Contrast Medium CT

Iodinated contrast medium (ICM) dose reduction is beneficial for decreasing potential health risk to renal-insufficiency patients in CT scanning. Due to the lowintensity vessel in ultra-low-dose-ICM CT angiography, it cannot provide clinical diagnosis of vascular diseases. Angiography reconstruction for ultra-low-dose-ICM CT can enhance vascular intensity for directly vascular diseases diagnosis. However, the angiography reconstruction is challenging since patient individual differences and vascular disease diversity. In this paper, we propose a Multiple Adversarial Learning based Angiography Reconstruction (i.e., MALAR) framework to enhance vascular intensity. Specifically, a bilateral learning mechanism is developed for mapping a relationship between source and target domains rather than the image-to-image mapping. Then, a dual correlation constraint is introduced to characterize both distribution uniformity from across-domain features and sample inconsistency with domain simultaneously. Finally, an adaptive fusion module by combining multiscale information and long-range interactive dependency is explored to alleviate the interference of high-noise metal. Experiments are performed on CT sequences with different ICM doses. Quantitative results based on multiple metrics demonstrate the effectiveness of our MALAR on angiography reconstruction. Qualitative assessments by radiographers confirm the potential of our MALAR for the clinical diagnosis of vascular diseases. The code and model are available at https://github.com/HIC-SYSU/MALAR.

Discrepancy of echocardiography and computed tomography in initial assessment and 2-year follow-up for monitoring Marfan syndrome and related disorders

Patients with Marfan syndrome and related disorders are at risk for aortic dissection and aortic rupture and therefore require appropriate monitoring. Computed tomography (CT) and transthoracic echocardiography (TTE) are routinely used for initial diagnosis and follow-up. The purpose of this study is to compare whole-heart CT and TTE aortic measurement for initial work-up, 2-year follow-up, and detection of progressive aortic enlargement. This retrospective study included 95 patients diagnosed with Marfan syndrome or a related disorder. All patients underwent initial work-up including aortic diameter measurement using both electrocardiography-triggered whole-heart CT and TTE. Forty-two of these patients did not undergo aortic repair after initial work-up and were monitored by follow-up imaging within 2 years. Differences between the two methods for measuring aortic diameters were compared using Bland-Altman plots. The acceptable clinical limit of agreement (acLOA) for initial work-up, follow-up, and progression within 2 years was predefined as <  ± 2 mm. Bland-Altman analysis revealed a small bias of 0.2 mm with wide limits of agreement (LOA) from + 6.3 to - 5.9 mm for the aortic sinus and a relevant bias of - 1.6 mm with wide LOA from + 5.6 to - 8.9 mm for the ascending aorta. Follow-up imaging yielded a small bias of 0.5 mm with a wide LOA from + 6.7 to - 5.8 mm for the aortic sinus and a relevant bias of 1.1 mm with wide LOA from + 8.1 to - 10.2 mm for the ascending aorta. Progressive aortic enlargement at follow-up was detected in 57% of patients using CT and 40% of patients using TTE. Measurement differences outside the acLOA were most frequently observed for the ascending aorta. Whole-heart CT and TTE measurements show good correlation, but the frequency of measurement differences outside the acLOA is high. TTE systematically overestimates aortic diameters. Therefore, whole-heart CT may be preferred for aortic monitoring of patients with Marfan syndrome and related disorders. TTE remains an indispensable imaging tool that provides additional information not available with CT.

Risk factors of anaphylaxis in Korea: Identifying drug-induced anaphylaxis culprits using big data

Drug-induced anaphylaxis is a fatal medical condition whose incidence has been increasing continuously. Due to differences between genetic backgrounds and health care systems, different populations may be prone to various causative drugs. Using the Health Insurance Service and Assessment Service database, we investigated culprit drugs for drug-induced anaphylaxis and common medication risk factors in the Korean general population. We collected medical prescription histories within 3 days prior to anaphylaxis between January 2011 and December 2019 from the HIRA database. Designed as a case-crossover study, the attributable visits (case visits) were matched to medical visits (control visits) with the drug sets for each visit. We collected a list of medication risk factors for anaphylaxis and calculated the risk ratio of each agent using the chi-square test and conditional logistic regression analysis. A total of 159,473 individuals were listed in the database with a diagnosis of anaphylaxis in the HIRA from 2011 to 2019. After evaluating the suitability of control visits for matching with a case visit, 8168 subjects and 767 drugs were analyzed. The chi-square analysis identified 31 drugs as potential risk factors for drug-induced anaphylaxis in Korea. After applying a conditional logistic regression analysis for each agent, 5 drugs were found to be the common medication risk factors for drug-induced anaphylaxis: cefaclor, iopromide, iohexol, iomeprol, and tolperisone. We found 5 medication risk factors that showed the highest risk of drug-induced anaphylaxis and their degree of risk using an objective methodology in the Korean general population.

Hypersensitivity reactions to iodinated radiocontrast media: Cluster analysis reveals distinct clinical phenotypes

Background

Drug hypersensitivity reaction (DHR) to iodinated radiocontrast media (iRCM) is reported in 1%–3% of injections. Risk assessment of patients with suspicion of DHR to iRCM relies solely on clinical phenotyping and drug allergy workup. Using a novel unsupervised TwoStep cluster analysis, we aimed to identify prototypic patterns within a large cohort of patients evaluated for a potential iRCM DHR.

Methods

A retrospective study was conducted using data from the Drug Allergy and Hypersensitivity Database of the Allergy Unit, University Hospital of Montpellier, Montpellier, France. All referred patients during February 2001 to December 2019 with suspicion of iRCM DHR with either confirmed positive or confirmed negative skin tests were included in the analysis.

Results

A total of 1439 patients were evaluated. The chronology of the index reaction was immediate and nonimmediate in 77.1% and 22.4%, respectively. Cluster analysis categorized the total study population in 5 clusters. Cluster 1 compiled all nonimmediate and cluster 2–5 almost all immediate reactors. Cluster 1 and 2 had recent reactions (<1 y) with mostly known iRCMs and the highest iRCM allergy prevalence (16–17%). In the other clusters, more remote reactions, unknown iRCMs and a lower allergy prevalence (3–8%) was observed. Chronology and semiology of the index reaction were the factors most strongly differentiated among clusters. History of anaphylactic shock and chronology of immediate hypersensitivity reactions were shown to be independent predictors of allergy with adjusted OR (aOR) of 4.68 (95%CI: 3.01–7.27, p < 0.001) and 2.51 (95%CI: 1.67–3.78, p < 0.001), respectively.

Conclusions

Unsupervised cluster analysis identified 5 prototypic patterns within patients with a suspected DHR to iRCMs. Well-phenotyped patients cluster together in 2 groups in which the prevalence of allergy is approximately 1 in 6. However, this value decreases for patients with reactions dating back to more than a decade.

Incidence and Risk Factors of Immediate Hypersensitivity Reactions and Immunization Stress-related Responses With COVID-19 mRNA Vaccine

Background

With the implementation of mass vaccination campaigns against COVID-19, the safety of vaccine needs to be evaluated.

Objective

We aimed to assess the incidence and risk factors for immediate hypersensitivity reactions (IHSR) and immunization stress–related responses (ISRR) with the Moderna COVID-19 vaccine.

Methods

This nested case-control study included recipients who received the Moderna vaccine at a mass vaccination center, Japan. Recipients with IHSR and ISRR were designated as cases 1 and 2, respectively. Controls 1 and 2 were selected from recipients without IHSR or ISRR and matched (1 case: 4 controls) with cases 1 and cases 2, respectively. Conditional logistic regression analysis was used to identify risk factors associated with IHSR and ISRR.

Results

Of the 614,151 vaccine recipients who received 1,201,688 vaccine doses, 306 recipients (cases 1) and 2478 recipients (cases 2) showed 318 events of IHSR and 2558 events of ISRR, respectively. The incidence rates per million doses were estimated as IHSR: 266 cases, ISRR: 2129 cases, anaphylaxis: 2 cases, and vasovagal syncope: 72 cases. Risk factors associated with IHSR included female, asthma, atopic dermatitis, thyroid diseases, and a history of allergy; for ISRR, the risk factors were younger age, female, asthma, thyroid diseases, mental disorders, and a history of allergy and vasovagal reflex.

Conclusion

In the mass vaccination settings, the Moderna vaccine can be used safely owing to the low incidence rates of IHSR and anaphylaxis. However, providers should be aware of the occurrence of ISRR. Although recipients with risk factors are associated with slightly increased risks of IHSR and ISRR, this is not of sufficient magnitude to warrant special measures regarding their vaccination.

Differences in the Recurrence Rate of Immediate Adverse Drug Reactions According to the Components of Alternative Contrast Media: Analysis of Repetitive Computed Tomography Cases in a Single Tertiary Hospital

INTRODUCTION

The recurrence rates of immediate adverse drug reactions (ADRs) to the alternative radiocontrast media (RCM) are not well known. Previous studies suggest selection of alternative RCM considering carbamoyl side chains; however, its usefulness for preventing the recurrence of ADRs has not been clearly verified.

OBJECTIVE

The aim of this study was to verify the recurrence rate of immediate ADRs according to the alternative RCM.

METHOD

This retrospective study analyzed 6420 contrast-enhanced computed tomography (CT) cases of 2009 patients registered in the ADR system from 861,664 CT cases in a single tertiary hospital between 2015 and 2020. Iohexol, iopromide, iobitridol, and iopamidol were used for CT. According to the carbamoyl side chains present, iohexol belongs to group 1, iopromide belongs to groups 1 and 2, iobitridol belongs to group 2, and iopamidol belongs to group 3.

RESULTS

Replacing iobitridol with iopamidol (odds ratio [OR] 2.595, 95% confidence interval [CI] 1.48-4.550) or iopromide (OR 3.354, 95% CI 1.420-7.926) as the subsequent RCM was associated with increased recurrence, while replacing iopamidol with iobitridol (OR 0.506, 95% CI 0.282-0.908) and iopromide with iohexol (OR 0.355, 95% CI 0.177-0.711) was associated with decreased recurrence. Other changes did not influence the recurrence of ADRs.

CONCLUSIONS

The recurrence of immediate ADRs increased in certain RCM combinations of preceding and subsequent CT scans, and the RCMs did not show cross-reactivity. Therefore, the clinical benefit of the alternative RCM considering cross-reactivity is limited. This result suggests that the side chains of RCM do not have an important role in the recurrence of immediate ADRs.