Imaging in a Pandemic: How Lack of Intravenous Contrast for Computed Tomography Affects Emergency Department Throughput.

Introduction: During the coronavirus 2019 pandemic, hospitals in the United States experienced a shortage of contrast agent, much of which is manufactured in China. As a result, there was a significantly decreased amount of intravenous (IV) contrast available. We sought to determine the effect of restricting the use of IV contrast on emergency department (ED) length of stay (LOS). Methods: We conducted a single-institution, retrospective cohort study on adult patients presenting with abdominal pain to the ED from March 7-July 5, 2022. Of 26,122 patient encounters reviewed, 3,028 (11.6%) included abdominopelvic CT with a complaint including "abdominal pain." We excluded patients with outside imaging and non-ED scans. Routine IV contrast agent was administered to approximately 74.6% of patients between March 7-May 6, 2022, when we altered usage guidelines due to a nationwide shortage. Between May 6-July 5, 2022, 32.8% of patients received IV contrast after institutional recommendations were made to limit contrast use. We compared patient demographics and clinical characteristics between groups with chi-square test for frequency data. We analyzed ED LOS with nonparametric Wilcoxon rank-sum test for continuous measures with focus before and after new ED protocols. We also used statistical process control charts and plotted the 1, 2 and 3 sigma control limits to visualize the variation in ED LOS over time. The charts include the average (mean) of the data and upper and lower control limits, corresponding to the number of standard deviations away from the mean. Results: After use of routine IV contrast was discontinued, ED LOS (229.0 vs 212.5 minutes, P = <0.001) declined by 16.5 minutes (95% confidence interval -10, -22). Conclusion: Intravenous contrast adds significantly to ED LOS. Decreased use of routine IV contrast in the ED accelerates time to CT completion. A policy change to limit IV contrast during a national shortage significantly decreased ED LOS.

Anomalous origin of the circumflex artery from the right pulmonary artery.

Anomalous origin of the circumflex artery from the pulmonary artery (ACxAPA) is a rare but clinically significant condition in which the circumflex artery arises from either the main pulmonary artery or one of its main branches. Untreated patients with ACxAPA may develop severe heart failure or sudden cardiac death. Diagnosis is established with either catheter or CT angiography. We present a case of an adult male with no prior known cardiac history who was found to have ACxAPA after presenting to our institution in acute decompensated heart failure.

Multi-Modality Imaging in Vasculitis.

Systemic vasculitides are a rare and complex group of diseases that can affect multiple organ systems. Clinically, presentation may be vague and non-specific and as such, diagnosis and subsequent management are challenging. These entities are typically classified by the size of vessel involved, including large-vessel vasculitis (giant cell arteritis, Takayasu's arteritis, and clinically isolated aortitis), medium-vessel vasculitis (including polyarteritis nodosa and Kawasaki disease), and small-vessel vasculitis (granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis). There are also other systemic vasculitides that do not fit in to these categories, such as Behcet's disease, Cogan syndrome, and IgG4-related disease. Advances in medical imaging modalities have revolutionized the approach to diagnosis of these diseases. Specifically, color Doppler ultrasound, computed tomography and angiography, magnetic resonance imaging, positron emission tomography, or invasive catheterization as indicated have become fundamental in the work up of any patient with suspected systemic or localized vasculitis. This review presents the key diagnostic imaging modalities and their clinical utility in the evaluation of systemic vasculitis.

Top down and bottom up: A review of strategies for wellness programs in academic radiology.

Formal physician-wellness programs have come into vogue in professional organizations in recent years. Wellness programs in academic centers vary from institution to institution but foundational to all is their aim to reduce burnout and increase professional fulfillment. As radiologists in charge of wellness program implementation in different academic institutions, we describe existing academic radiology wellness programs with two detailed examples. Physician well-being programs need to be both leadership-driven (i.e., "top down") and receptive to feedback ("bottom up").

Cardiac Allograft Vasculopathy: Challenges and Advances in Invasive and Non-Invasive Diagnostic Modalities.

Cardiac allograft vasculopathy (CAV) is a distinct form of coronary artery disease that represents a major cause of death beyond the first year after heart transplantation. The pathophysiology of CAV is still not completely elucidated; it involves progressive circumferential wall thickening of both the epicardial and intramyocardial coronary arteries. Coronary angiography is still considered the gold-standard test for the diagnosis of CAV, and intravascular ultrasound (IVUS) can detect early intimal thickening with improved sensitivity. However, these tests are invasive and are unable to visualize and evaluate coronary microcirculation. Increasing evidence for non-invasive surveillance techniques assessing both epicardial and microvascular components of CAV may help improve early detection. These include computed tomography coronary angiography (CTCA), single-photon emission computed tomography (SPECT), positron emission tomography (PET), and vasodilator stress myocardial contrast echocardiography perfusion imaging. This review summarizes the current state of diagnostic modalities and their utility and prognostic value for CAV and also evaluates emerging tools that may improve the early detection of this complex disease.

Aortic Valve Calcium Score by Computed Tomography as an Adjunct to Echocardiographic Assessment-A Review of Clinical Utility and Applications.

Aortic valve stenosis (AS) is increasing in prevalence due to the aging population, and severe AS is associated with significant morbidity and mortality. Echocardiography remains the mainstay for the initial detection and diagnosis of AS, as well as for grading of severity. However, there are important subgroups of patients, for example, patients with low-flow low-gradient or paradoxical low-gradient AS, where quantification of severity of AS is challenging by echocardiography and underestimation of severity may delay appropriate management and impart a worse prognosis. Aortic valve calcium score by computed tomography has emerged as a useful clinical diagnostic test that is complimentary to echocardiography, particularly in cases where there may be conflicting data or clinical uncertainty about the degree of AS. In these situations, aortic valve calcium scoring may help re-stratify grading of severity and, therefore, further direct clinical management. This review presents the evolution of aortic valve calcium score by computed tomography, its diagnostic and prognostic value, as well as its utility in clinical care.

Dual Energy Technique Adds Value to Solitary Pulmonary Nodule Analysis with Dynamic Contrast-Enhanced CT: A 100 Nodule Experience.

A highly sensitive test for evaluation of solitary pulmonary nodules (SPN) involves a 5-phase, contrast enhanced CT evaluation which can be fraught with technical error. The goal of this study is to determine if qualitative evaluation of iodine maps with dual energy CT (DECT) can add value to SPN evaluation.100 patients had their SPN evaluated with traditional quantitative analysis and qualitative evaluation with iodine maps generated from DECT data acquired at 80 kVp and 140 kVp. Quantitative analysis served as the gold standard. Quantitative analysis was performed at 1, 2, 3, and 4 minutes. Qualitative Iodine maps analysis was performed at 1 and 2 minutes. Sensitivity and specificity were 63% and 95%, and 73% and 91%, respectively, at 1 and 2 minutes. Combined analysis resulted in sensitivity of 67% and specificity of 94%. Six of 7 false negatives on combined analysis were stable for 2 years and the seventh was lost to follow up after 1 year. Of 5 false positives on combined analysis; 2 were due to 'bleed-through of calcium' on iodine maps, 2 were positive on 3 and 4-minute quantitative analysis with one biopsy-proven adenocarcinoma. Qualitative analysis of Iodine maps generated using DECT data can be easily performed and may provide more effective evaluation of the solitary pulmonary nodule when combined with traditional analysis. This method warrants further investigation with larger patient populations, comparison with PET-CT, and evaluation of outcomes including long-term nodule stability and tissue diagnosis.

Improving Turnaround Time in a Hospital-based CT Division with the Kaizen Method.

The Kaizen method is an approach to lean process improvement that is based on the idea that small ongoing positive changes can lead to major improvements in efficiency and reduction of waste. The hospital-based CT division at Mayo Clinic Arizona had been receiving numerous concerns of delays in the performance of examinations from inpatients, outpatients, and patients presenting to the emergency department. These concerns, along with a planned hospital expansion, provided the impetus to perform a process improvement project with the goal of reducing inpatient, emergency department, and outpatient turnaround times by 20%. Kaizen process improvement was chosen because of the emphasis on reduction of waste, standardization, and empowerment of frontline staff. The project was led by a process improvement coach who was trained in lean process improvement and A3 thinking. At the end of a weeklong Kaizen event, inpatient turnaround time decreased by 54%, emergency department turnaround time decreased by 29%, and outpatient turnaround time decreased by 45%. These results were achieved and sustained by establishing standardized work, developing frontline problem solvers, instituting visual management, aligning with relevant metrics, emphasizing patient and staff satisfaction, and reducing lead time and non-value-added work. When done properly, a Kaizen event can be an effective tool for process improvement in the health care setting. Online supplemental material is available for this article. ©RSNA, 2022.

Kaizen Process Improvement in Radiology: Primer for Creating a Culture of Continuous Quality Improvement.

Kaizen process improvement is an element of lean production that is an approach to creating continuous improvement. Kaizen is based on the idea that small ongoing positive changes in workflow and elimination of waste can yield major improvements over time. A focused Kaizen event, or rapid process improvement event, can lead to sustainable process improvement in health care settings that are resistant to change. This approach has been proven to be successful in health care. These events are led by a trained facilitator and coach who provides appropriate team education and engagement. To ensure success, the team must embrace the Kaizen culture, which emphasizes the development of a "learning organization" that is focused on relentless pursuit of perfection. The culture empowers all staff to improve the work they perform, with an emphasis on the process and not the individual. Respect for individual people is key in Kaizen. In radiology, this method has been successful in empowering frontline staff to improve their individual workflows. A 5-day Kaizen event has been successful in increasing on-time starts, decreasing lead time, increasing patient and staff satisfaction, and ensuring sustainability. Sustainable success can occur when the team stays true to lean principles, engages leaders, and empowers team members with the use of timely data to drive decision making. Online supplemental material is available for this article. ©RSNA, 2022.

Safety of magnetic resonance imaging in patients with cardiac implantable electronic devices with generator and lead(s) brand mismatch.

Magnetic resonance imaging (MRI) is a valuable imaging modality for the assessment of both cardiac and non-cardiac structures. With a growing population of patients with cardiovascular implantable electronic devices (CIEDs), 50%-75% of these patients will need an MRI. MRI-conditional CIEDs have demonstrated safety of MRI scanning with such devices, yet non-conditional devices such as hybrid CIEDs which have generator and lead brand mismatch may pose a safety risk. In this retrospective study, we examined the outcomes of patients with hybrid CIEDs undergoing MRI compared to those patients with non-hybrid CIEDs. A total of 349 patients were included, of which 24 patients (7%) had hybrid CIEDs. The primary endpoint was the safety of MRI for patients with hybrid CIEDs as compared to those with non-hybrid devices, measured by the rate of adverse events, including death, lead or generator failure needing immediate replacement, loss of capture, new onset arrhythmia, or power-on reset. Secondary endpoints consisted of pre- and post-MRI changes of decreased P-wave or R-wave sensing by ≥50%, changes in pacing lead impedance by ≥50 ohms, increase in pacing thresholds by ≥ 0.5 V at 0.4 ms, and decreasing battery voltage of ≥ 0.04 V. The primary endpoint of any adverse reaction was present in 1 (4.2%) patient with a hybrid device, and consistent of atrial tachyarrhythmia, and in 10 (3.1%) patients with a non-hybrid device, and consisted of self-limited atrial and non-sustained ventricular arrhythmias; this was not statistically significant. No significant differences were found in the secondary endpoints. This study demonstrates that MRI in patients with hybrid CIEDs does not result in increased patient risk or significant device changes when compared to those patients who underwent MRI with non-hybrid CIEDs.

Myocardial Cut-off Sign is a Sensitive and Specific Cardiac Computed Tomography and Magnetic Resonance Imaging Sign to Distinguish Left Ventricular Pseudoaneurysms From True Aneurysms.

PURPOSE: The purpose of this study was to describe the myocardial cut-off sign, assess its ability to distinguish left ventricular pseudoaneurysms (LV PSAs) from true aneurysms (LVAs), and compare its performance with other imaging findings and quantitative measurements used to differentiate LV PSAs from LVAs. MATERIALS AND METHODS: This retrospective single-center study identified patients with preoperative cardiac computed tomography (CT) or magnetic resonance imaging (MRI) and surgically confirmed LVAs or LV PSAs over a 10-year period. Seventeen LV PSAs (11 MRI, 6 CT) and 18 LVAs (10 MRI, 8 CT) were included. The myocardial cut-off sign was objectively a >50% decrease in aneurysm sac wall thickness measured at 1 cm from the aneurysmal neck (measurements at 2 cm were also assessed) and subjectively an abrupt "cut-off" of myocardium for the aneurysm sac for PSA compared with a gradual tapering of sac wall thickness for LVA. Two radiologists independently evaluated images for the subjective presence of this sign. RESULTS: The myocardial cut-off sign was 91% sensitive and 97% specific when measured 1 cm from the aneurysm neck. When measured at 2 cm from the neck, the sign was 100% sensitive and 69% specific. Subjective analysis of whether the myocardium appeared "cut-off" was 94% to 100% sensitive and 78% to 94% specific with excellent agreement for both PSA (κ=0.94) and LVA (κ=0.83). CONCLUSIONS: The myocardial cut-off sign on cardiac CT and MRI is a sensitive and specific finding of LV PSA. Specificity is improved with objective measurements compared with subjective assessment (97% vs. 78% to 94%). This sign may help radiologists distinguish between LV PSAs and LVAs.

Successful Treatment of Steroid-Refractory Checkpoint Inhibitor Myocarditis with Globulin Derived-Therapy: A Case Report and Literature Review.

Immune checkpoint inhibitor (ICI) monoclonal antibody drugs are an important interface of immunology and cancer biology with the intended goal to create cancer specific treatments with less systemic toxicity. Recognition of immune-related adverse events is critical and these include significant cardiovascular toxicity and myocarditis. Compared with other immune-related events, ICI associated myocarditis is rare but is associated with high mortality. The majority of cases present early in the course of therapy and patients can rapidly progress to fulminant myocarditis. Initially, the mainstay of treatment in patients with ICI-associated myocarditis is immunosuppressive therapy with glucocorticoids. For those who do not respond to steroids, the optimal treatment is unclear. This review summarizes the potential adjunctive treatment options for patients with steroid-refractory myocarditis by illustrating a case of myocarditis that was treated with Thymoglobulin and immunoglobulin.

Comparison of echocardiographic parameters with cardiac magnetic resonance imaging in the assessment of right ventricular function.

INTRODUCTION: The right ventricle (RV) strain measured by speckle tracking (RVS) is an echocardiographic parameter used to assess RV function. We compared RVS to RV fractional area change (FAC%), tricuspid annular plane systolic excursion (TAPSE) and Doppler tissue imaging-derived peak systolic velocity (S') in the assessment of right ventricular (RV) systolic function measured using cardiac magnetic resonance imaging (MRI). METHODS: We enrolled consecutive patients who underwent cardiac MRI between Jan 2012 and Dec 2017 and a transthoracic echocardiogram (TTE) within 1 month of the MRI with no interval event. Baseline clinical characteristics and MRI parameters were extracted from chart review. Echocardiographic parameters were measured prospectively. TTE parameters including RVS, TAPSE, S', and FAC% were tested for accuracy to identify impaired RV EF (EF < 45% & <30%) using receiver operator curves. RESULTS: The study cohort included 500 patients with mean age 55 years ± 18 and peak tricuspid regurgitation velocity 2.7 ± 1.4 m/s. The area under ROC for RVS was 0.69 (95% CI 0.63-0.75) and 0.78 (95% CI 0.70-0.88) to predict RVEF < 45% & RVEF < 30%, respectively. The RV FAC% had second highest accuracy of predicting RVEF among all the TTE parameters tested in study. CONCLUSION: Right ventricular strain is the most accurate echocardiographic method to detect impaired right ventricular systolic function when using MRI as the gold standard.

A Unique Compensatory Mechanism for Total Pulmonary Vein Occlusion Post Atrial Fibrillation Catheter Ablation Visualized by Multimodality Imaging.

Pulmonary vein (PV) stenosis is a rare and serious complication of radiofrequency catheter ablation (RFCA) for atrial fibrillation. However, it can be asymptomatic or mildly symptomatic depending on the severity of the stenosis and the development of compensatory mechanisms. This study provides a detailed description and visualization of a unique type of venous collaterals that bypass the PV stenosis and drain directly in the left atrium alleviating PV stenosis sequelae. This study reports a case of a 61-year-old male who presented with mild dyspnea and fatigue 3 years post atrial fibrillation RFCA. After a thorough evaluation of the case, a redo-ablation was planned. As a part of the preablation workup, a transesophageal echocardiography (TEE), a ventilation-perfusion (V/Q) scan of the lungs, and a chest computed tomography angiogram (CTA) were performed. The TEE revealed total obstruction of the left superior PV, with no color Doppler flow detected. It also showed evidence of multiple collateral flows at the os of the left superior PV. The V/Q scan showed a large perfusion defect involving the entire left upper lobe consistent with a compromised left upper PV flow. The CTA with 3D volume rendering revealed the total occlusion of the left superior PV at its ostium. Moreover, the scan confirmed the pulmonary venous drainage via small collateral channels that was suggested by the TEE.

Multimodality Imaging Demonstrating an Apical Variant Hypertrophic Cardiomyopathy in an Uncommon Pentad.

A 79-year-old man was admitted for a transcatheter aortic valve replacement due to severe aortic stenosis. A preoperative chest computed tomography with angiography revealed an apical variant hypertrophic cardiomyopathy with a prominent apical pouch. In addition, there was near-complete obliteration of the left ventricle in the mid to apical aspect during systole suggesting a midventricular gradient. Postoperative transthoracic echocardiography confirmed the apical variant hypertrophic cardiomyopathy with an apical aneurysm and a gradient with a peak velocity of 2 m/s, and mid-cavitary gradient with a peak velocity of 3 m/s. It also revealed a fusiform aneurysmal dilatation of the ascending aorta.