Management of Severe Allergic-Like Contrast Media Reactions: Pitfalls and Strategies, From the AJR Special Series on Contrast Media.

Adverse reactions to contrast media are often high-acuity events that are uncommon potentially life-threatening. Nonetheless, these events are treatable, and radiologists may be called upon to manage a contrast media reaction. However, because these events are infrequent, they are prone to management errors. This article highlights common pitfalls and practical tips for the management of acute contrast media reactions in children and adults. Recognition of frequent management errors and implementation of the mitigation strategies presented can ameliorate risk and improve patient outcomes. These measures include proper training on reaction management and medication administration, the prompt use of IM epinephrine autoinjectors whenever a severe allergic-like reaction is suspected, the use of visual aids for quick reference in the setting of a reaction, and the recognition of adverse events that are not allergic-like reactions, which commonly require only supportive care.

Clinical Importance of Incidental Homogeneous Renal Masses That Measure 10-40 mm and 21-39 HU at Portal Venous Phase CT: A 12-Institution Retrospective Cohort Study.

BACKGROUND. Incidental homogeneous renal masses are frequently encountered at portal venous phase CT. The American College of Radiology Incidental Findings Committee's white paper on renal masses recommends additional imaging for incidental homogeneous renal masses greater than 20 HU, but single-center data and the Bosniak classification version 2019 suggest the optimal attenuation threshold for detecting solid masses should be higher. OBJECTIVE. The purpose of this article is to determine the clinical importance of small (10-40 mm) incidentally detected homogeneous renal masses measuring 21-39 HU at portal venous phase CT. METHODS. We performed a 12-institution retrospective cohort study of adult patients who underwent portal venous phase CT for a nonrenal indication. The date of the first CT at each institution ranged from January 1, 2008, to January 1, 2014. Consecutive reports from 12,167 portal venous phase CT examinations were evaluated. Images were reviewed for 4529 CT examinations whose report described a focal renal mass. Eligible masses were 10-40 mm, well-defined, subjectively homogeneous, and 21-39 HU. Of these, masses that were shown to be solid without macroscopic fat; classified as Bosniak IIF, III, or IV; or confirmed to be malignant were considered clinically important. The reference standard was renal mass protocol CT or MRI, ultrasound of definitively benign cysts or solid masses, single-phase contrast-enhanced CT or unenhanced MRI showing no growth or morphologic change for 5 years or more, or clinical follow-up 5 years or greater. A reference standard was available for 346 masses in 300 patients. The 95% CIs were calculated using the binomial exact method. RESULTS. Eligible masses were identified in 4.2% of patients (514/12,167; 95% CI, 3.9-4.6%). Of 346 masses with a reference standard, none were clinically important (0%; 95% CI, 0-0.9%). Mean mass size was 17 mm; 72% (248/346) measured 21-30 HU, and 28% (98/346) measured 31-39 HU. CONCLUSION. Incidental small homogeneous renal masses measuring 21-39 HU at portal venous phase CT are common and highly likely benign. CLINICAL IMPACT. The change in attenuation threshold signifying the need for additional imaging from greater than 20 HU to greater than 30 HU proposed by the Bosniak classification version 2019 is supported.

Platinum response characteristics of patients with pancreatic ductal adenocarcinoma and a germline BRCA1, BRCA2 or PALB2 mutation.

BACKGROUND: Retrospective studies suggest a survival benefit when platinum-based chemotherapy is administered to patients with pancreatic cancer harbouring a germline mutation in BRCA1, BRCA2 or PALB2 (mut-positive PDAC). However, the objective response rate (ORR) and real-world progression free survival (rwPFS) achieved with such treatment remain ill-defined. METHODS: Twenty-six patients with advanced-stage mut-positive PDAC who had been treated with platinum-based therapy were matched by age, race and sex to 52 platinum-treated control PDAC patients. Responses to therapy were determined by RECIST v1.1, performed by blinded radiology review. Measured outcomes included ORR and rwPFS. RESULTS: The ORR in mut-positive patients was 58% compared to 21% in the control group (p = 0.0022). There was no significant difference in ORR between platinum regimens in mut-positive patients (p = 0.814), whereas in control patients, the only observed responses were to FOLFIRINOX. rwPFS was 10.1 mo. for mut-positive patients and 6.9 mo. for controls (HR 0.43; 95% CI 0.25-0.74; 0.0068). CONCLUSION: Mut-positive PDAC has a high ORR and prolonged rwPFS to platinum-based chemotherapy. These findings may have implications particularly in the neoadjuvant setting, and for future clinical trial design, and highlight the importance of early germline testing in patients with PDAC.

Benefit of a Visual Aid in the Management of Moderate-Severity Contrast Media Reactions.

OBJECTIVE: The purpose of this study was to compare management of moderate-severity reactions with and without a visual aid or flowchart in contrast medium reaction simulations. SUBJECTS AND METHODS: All attending radiologists and trainees were requested to participate in a contrast medium reaction simulation program, including a moderate-severity reaction scenario, and were randomized to groups having or not having a visual aid. The time to administer intramuscular (IM) epinephrine via automated injector and errors in administration were recorded. After the simulation, all participants completed a survey assessing their comfort in treating reactions to contrast media with and without a visual aid. RESULTS: A total of 138 participants were divided into 21 sessions in the program, with 68 participants in the moderate-severity reaction scenario. Eleven groups were provided a visual aid; 10 groups were not. Errors in management occurred in 18.2% (2 of 11) of groups with visual aids versus 40% (4 of 10) in groups without (p = 0.35), with epinephrine self-administration reflecting the most common error. Excluding the groups with errors, the mean time to administration of IM epinephrine was 97 seconds with versus 152 seconds without the visual aid (p = 0.04). Of the 138 participants, 97.8% agreed that the poster would aid in medication administration, and 87% agreed that it would help decrease time to administer medications. CONCLUSION: A visual aid increased the subjective confidence of radiologists in the dose and route of medication administration in the contrast medium reaction simulation and led to faster administration of epinephrine. Self-administration IM epinephrine errors were common and seen in both groups.

JOURNAL CLUB: Benefit of Epinephrine Autoinjector for Treatment of Contrast Reactions: Comparison of Errors, Administration Times, and Provider Preferences.

OBJECTIVE: Given the rarity of contrast reactions in practice, most radiologists have little to no experience in their management, and errors are common. The purpose of this study was to compare treatment of a moderate-severity reaction with intramuscular epinephrine by either the traditional manual method of drawing up and delivering epinephrine with a needle and syringe or the use of an epinephrine autoinjector. SUBJECTS AND METHODS: All diagnostic radiologists at the study institution were requested to participate in an annual contrast reaction simulation program, which consisted of three simulation scenarios in a high-fidelity simulation laboratory. During the moderate-severity simulation scenario, the time to administer intramuscular epinephrine and any errors in administration were recorded. Groups were randomized to use an autoinjector device or manual delivery. All participants completed a survey assessing the experience with epinephrine and their comfort in treating contrast reactions using a traditional manual approach versus an epinephrine autoinjector. RESULTS: Among 189 participants in the contrast reaction simulation program, 76 participated in a moderate-severity reaction simulation two to five at a time in 25 sessions. Mean total time to administration was significantly longer for manual (108.8 seconds) than for autoinjector (38.7 seconds) delivery (p < 0.001). There were 11 errors in the manual group and one error in the autoinjector group (p = 0.005). Ninety-four percent of participants reported feeling very comfortable or comfortable with the autoinjector as opposed to 60% for manual delivery (p < 0.001). Overall, 96% of participants thought the autoinjector was easier to use. CONCLUSION: Use of an epinephrine autoinjector for treatment of contrast reactions was associated with a significantly greater degree of provider comfort, shorter time to administration, and fewer errors.

Deferral of Estimated Glomerular Filtration Rate Testing Before Contrast-Enhanced CT in Low-Risk Emergency Department Patients: Assessment of Safety and Impact on Throughput.

OBJECTIVE: To assess the safety and utility of deferring estimated glomerular filtration rate (eGFR) testing before contrast-enhanced CT (CECT) in low-risk emergency department (ED) patients. METHODS: A new question was added to CECT order screens, allowing ordering ED providers to defer eGFR testing in patients deemed low risk for contrast-induced acute kidney injury (AKI). Low risk was defined as no known chronic kidney disease (CKD) or risk factors for AKI or CKD. Patients on chronic dialysis were deemed low risk. The project included three phases: baseline, pilot (optional order question), and full implementation (required order question). Outcomes were operational throughput metrics of CECT order to protocol (O to P) and order to begin (O to B) times. As a balancing safety measure, the proportion of patients deemed to be "low risk" and subsequently found to have eGFR value less than 30 mL/min/1.73 m2 was reported. RESULTS: A total of 16,446 CECT studies were included from four EDs. In the pilot phase, provider engagement rates with the question were low (5%-14%). After full implementation, median O to P time improved from 23.93 min at baseline to 13.02 (P < .0001) and median O to B time improved from 80.34 min to 76.48 (P = .0002). In 0.3% (2 of 646) studies, CECT was completed in patients categorized as low risk by the ED provider with subsequently resulted eGFR <30 mL/min/1.73 m2. DISCUSSION: Upfront clinical risk assessment for AKI and CKD by ED providers can be used to safely defer eGFR testing and improve operational performance for patients requiring CECT.

A Survey of Practicing Radiologists on the Use of Premedication Before Intravenous Iodinated Contrast Medium Administration.

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.

Polyethylene glycol-based gels for treatment of prostate cancer: pictorial review of normal placement and complications.

Rectal spacers are commonly used in the radiotherapy for prostate cancers, serving as a means to protect the rectum and surrounding structures from radiation toxicity. Polyethylene Glycol-Based Gels (SpaceOAR ™ and Space-OAR Vue™, Boston Scientific) are the most commonly used rectal spacers. Given their increasingly widespread use and the relative paucity of radiology literature on this topic, it is imperative for the radiologist to recognize both the normal and abnormal placement of these polyethylene glycol-based rectal spacers, particularly as the latter may be associated with suboptimal therapy and/or complications.

Diseases of the pulmonary arteries: imaging appearances and pearls.

A wide spectrum of pathology, both congenital and acquired, can affect the pulmonary arteries. While some of these are commonly seen in everyday clinical practice, some are rare. These entities may be discovered incidentally at imaging for other reasons in an asymptomatic patient, however patients may go on to develop symptoms over the course of their lifetime. Although an enlarged pulmonary artery can be visualized on chest X-ray (CXR), for the most part, CXR is insensitive for detecting abnormalities of the pulmonary arteries. Contrast-enhanced chest CT (CECT) is a better test to evaluate the pulmonary arteries as it is readily available, quick to perform, able to provide multiplanar reformatted images, and noninvasive. CECT is not only able to assess the lumen and wall of the pulmonary artery, but also provides a detailed evaluation of the entire thorax, including the heart, mediastinal structures, and lungs, often times picking up associated findings, and is the mainstay for evaluating disorders of the pulmonary vasculature. MRI allows for detailed evaluation of the vessel wall which can be especially helpful in cases where malignancy or vasculitis are suspected, and is also able to provide useful physiologic data such as quantification of flow. It is important for the radiologist to be aware of the many conditions which affect the pulmonary arteries, as some may require urgent treatment. This article will review normal pulmonary artery anatomy and physiology, as well as the various imaging findings of pulmonary vascular pathologies.

Incidental Breast Findings on Computed Tomography and MR Imaging.

Computed tomography (CT) and magnetic resonance (MR) imaging may demonstrate a wide variety of incidental findings in the breast, including primary breast carcinoma, the second most common cancer in women. It important to recognize the spectrum of pathologic conditions in order to properly assess the need for further workup. Some findings may be diagnosed as benign on the basis of CT/ MR imaging and clinical history alone, whereas others will require evaluation with dedicated breast imaging and possibly biopsy. This article serves to guide radiologists' management of the wide spectrum of incidental breast findings encountered on cross-sectional imaging.

Does MR enterography offer added value after a recent CT in the evaluation of abdominal pain in Crohn's disease patients?

PURPOSE: To determine if there is added value in performing MR enterography shortly after a contrast-enhanced CT of the abdomen and pelvis in patients with Crohn's disease presenting with acute abdominal pain. MATERIALS AND METHODS: A total of 45 consecutive patients who underwent MRE examination <7 days after a CT met our strict inclusion criteria. Independent and blinded review of both MRE and CT exams was performed by two abdominal radiologists. RESULTS: There were no significant differences in detection of various findings associated with Crohn's disease between modalities. These findings included abscess, fistula, bowel wall thickening, free fluid, stricture, and bowel obstruction. There was moderate interobserver agreement with CT (Kappa: 0.52, 95% CI: [0.4-0.6]) and fair with MRE (Kappa: 0.36, 95% CI:[0.3 = 0.5]). CONCLUSION: The routine use of MRE after a diagnostic CT should be avoided, as it provides no additional valuable information, at the expense of extra patient risks, discomfort, and higher health care costs.

Neuroprotective and antiretroviral effects of the immunophilin ligand GPI 1046.

HIV infection results in a neurodegenerative disorder for which currently there is no effective therapy available. Currently, available antiretroviral therapy has no impact on the production of early regulatory HIV proteins once the virus is integrated. Of these proteins, Tat was shown to be toxic to neurons. We, thus, used an in vitro neuronal culture system to determine if immunophilin ligands could protect against Tat-induced neurotoxicity. We found that GPI 1046 had potent neuroprotective effects in this model. The compound was able to protect the neurons even though it only partially obliterated Tat-induced oxidative stress in neurons, suggesting that other mechanisms may be important in mediating its neuroprotective effect. Furthermore, GPI 1046 showed inhibition of HIV replication and Tat-mediated long terminal repeat (LTR) activation suggesting that this class of compounds may be worthy of further exploration as a potential treatment for HIV dementia.