Emergency department imaging utilization of cancer patients treated with bevacizumab: single-institution 8-year experience.

PURPOSE: This study aims to highlight the presentations, imaging, and clinical outcomes of cancer patients presenting to the emergency department (ED) while receiving bevacizumab (Avastin) therapy. METHODS: Our retrospective study was based on data from a single institution to identify cancer patients who presented acutely to the ED between 2014 and 2021 within 3 months of beginning bevacizumab who subsequently received diagnostic imaging with CT, MRI, ultrasound, and/or nuclear medicine ventilation/perfusion (VQ) scans. Data gathered included presenting symptoms grouped by body system, imaging impressions, and clinical outcomes, including hospitalization and discontinuation of bevacizumab after each ED visit. Imaging examinations and patient charts were reviewed by a team of fellowship-trained radiologists, radiology residents, and medical students. RESULTS: A total of 84 patients who presented to the ED were included for analysis. This included 32 (38.1%) males and 52 (61.9%) females, with a mean age of 61.2 years and an age range of 29-91 years. Neurological symptoms were the most common presenting symptoms, followed by abdominal symptoms and respiratory symptoms. Head imaging with CT and MRI was the most common imaging ordered with 55 total examinations, followed by abdominal imaging with 37 CT abdomen/pelvis (A/P) examinations, and then CT chest imaging with 22 examinations. Imaging revealed a serious adverse drug reaction in 21 (25.0%) patients, disease progression in 19 (22.6%), and no acute imaging findings in 44 (52.4%) patients. Imaging diagnoses were significantly associated with treatment planning, with a positive determination of bevacizumab-related serious adverse reaction on imaging leading to discontinuation of bevacizumab (p = 0.001). CONCLUSION: Multimodality imaging was a commonly used assessment tool for cancer patients receiving bevacizumab who presented to the ED. Imaging played a crucial role in diagnosis in these patients, especially of treatment-related serious adverse reactions and disease progression. Positive imaging findings of serious adverse reactions affected patient management including discontinuation of bevacizumab.

Comparative Performance of Whole-Body MRI and FDG PET/CT in Evaluation of Multiple Myeloma Treatment Response: Systematic Review and Meta-Analysis.

BACKGROUND. Traditional approaches for evaluating multiple myeloma (MM) treatment response have low sensitivity for residual disease. Recent studies highlight the utility of whole-body MRI or FDG PET/CT in evaluating treatment response, with increasing emphasis on DWI. OBJECTIVE. This systematic review was conducted to assess the diagnostic accuracy of whole-body MRI and FDG PET/CT for MM treatment response assessment. EVIDENCE ACQUISITION. Studies in which whole-body MRI or FDG PET/CT was used to evaluate MM treatment response were identified through search of the PubMed and EMBASE databases through June 30, 2021. Pooled sensitivity and specificity for detecting response were calculated by bivariate modeling. The diagnostic performances of whole-body MRI and FDG PET/CT were compared. Subgroup analyses were conducted to assess studies comparing the modalities and studies in which whole-body MRI included DWI. EVIDENCE SYNTHESIS. Twelve studies comprising 373 patients were included: six evaluated both modalities, four evaluated whole-body MRI only, and two evaluated FDG PET/CT only. Of studies of MRI, five included DWI. Pooled sensitivity and specificity were 87% (95% CI, 75-93%) and 57% (95% CI, 37-76%) for whole-body MRI versus 64% (95% CI, 45-79%) and 82% (95% CI, 75-88%) for FDG PET/CT (sensitivity, p = .29; specificity, p = .01). For studies directly comparing the modalities, pooled sensitivity and specificity were 90% (95% CI, 80-100%) and 56% (95% CI, 44-68%) for whole-body MRI versus 66% (95% CI, 47-85%) and 81% (95% CI, 72-90%) for FDG PET/CT (sensitivity, p = .18; specificity, p < .001). Sensitivity and specificity were 93% (95% CI, 75-98%) and 57% (95% CI, 21-87%) for DWI versus 74% (95% CI, 60-85%) and 56% (95% CI, 38-73%) for whole-body MRI without DWI (sensitivity, p = .27; specificity, p = .99). The AUC values were 0.84 for whole-body MRI, 0.83 for FDG PET/CT, and 0.92 for DWI. CONCLUSION. FDG PET/CT had significantly higher specificity, and whole-body MRI had higher sensitivity (though nonsignificant). DWI may contribute to the high sensitivity of whole-body MRI. CLINICAL IMPACT. The results of this meta-analysis suggest potential complementary roles of whole-body MRI and FDG PET/CT in assessment of MM treatment response. Future studies should explore their combination through PET/MRI.

A Decade of Success in Melanoma Immunotherapy and Targeted Therapy: What Every Radiologist Should Know.

ABSTRACT: Treatment strategies for malignant melanoma have rapidly evolved over the past decade. Because of its propensity to develop advanced stage and metastatic disease, melanoma has contributed to the majority of mortalities among patients with skin cancer. The development of novel therapeutics such as immunotherapy and targeted molecular therapies has revolutionized the treatment of patients with advanced stage and metastatic malignant melanoma. Immune checkpoint inhibitors, BRAF/MEK inhibitors, and other revolutionary therapies have demonstrated remarkable success in the treatment of this common malignancy. Along with these advancements in systemic therapies, imaging has continued to play a critical role in the diagnosis and follow-up of patients with malignant melanoma. As the use of these novel therapies continues to expand, knowledge of the evolving therapeutic landscape of melanoma is becoming critical for radiologists. In this review, we provide a primer for radiologists outlining the evolution of immunotherapy and targeted therapy in the treatment of melanoma. We discuss the critical role of imaging in evaluation of treatment response, including a summary of current imaging response guidelines. Last, we summarize the essential role of imaging in the evaluation of potential adverse events seen in patients with malignant melanoma undergoing treatment with immune checkpoint inhibitors.

Gas Where It Shouldn't Be! Imaging Spectrum of Emphysematous Infections in the Abdomen and Pelvis.

OBJECTIVE. The purpose of this article is to review the spectrum, etiopathogenesis, clinical presentation, imaging features, differential diagnoses, and management of emphysematous infections of the abdomen and pelvis. CONCLUSION. Emphysematous infections are associated with high morbidity and mortality and thus need urgent medical and surgical interventions. CT is the most sensitive modality to detect gas; CT provides definitive diagnosis in most cases and can depict the extent of involvement.

Role of Key Guidelines in an Era of Precision Oncology: A Primer for the Radiologist.

OBJECTIVE. The purpose of this article is to familiarize radiologists with the evidence-based imaging guidelines of major oncologic societies and organizations and to discuss approaches to effective implementation of the most recent guidelines in daily radiology practice. CONCLUSION. In an era of precision oncology, radiologists in practice and radiologists in training are key stakeholders in multidisciplinary care, and their awareness and understanding of society guidelines is critically important.

Cancer Clinical Trials: What Every Radiologist Wants to Know but Is Afraid to Ask.

OBJECTIVE. The purpose of this article is to provide radiologists with a guide to the fundamental principles of oncology clinical trials. The review summarizes the evolution and structure of modern clinical trials with an emphasis on the relevance of clinical trials in the field of oncologic imaging. CONCLUSION. Understanding the structure and clinical relevance of modern clinical trials is beneficial for radiologists in the field of oncologic imaging.

Past, Present, and Future of Serum Tumor Markers in Management of Ovarian Cancer: A Guide for the Radiologist.

The ability to accurately detect early ovarian cancer and subsequently monitor treatment response is essential to improving survival for patients with ovarian malignancies. Several serum tumor markers (STMs)-including cancer antigen 125 (CA-125), human epididymis protein 4 (HE4), cancer antigen 19-9 (CA 19-9), and carcinoembryonic antigen (CEA)-have been used as a noninvasive method of identifying ovarian cancer in conjunction with imaging. Although current guidelines do not recommend use of STMs as screening tools for ovarian cancer, these markers have clinical utility in both diagnosis and surveillance for women with ovarian cancer. CA-125 is the most commonly used STM; its level may be elevated in several types of ovarian cancer, including epithelial cell tumors, carcinosarcoma, teratomas, and secondary ovarian malignancies. An elevated level of CA 19-9 is associated with clear cell tumors, teratomas, and secondary malignancies. CEA is most commonly associated with mucinous ovarian cancers. Finally, HE4 is being increasingly used to identify certain subtypes of epithelial ovarian cancers, particularly serous and endometrioid tumors. Diagnosis of ovarian cancers relies on a combination of CA-125 levels and US findings, which include a large adnexal mass or high-risk features, including septa and increased vascularity. CT is preferred for staging and is used along with PET and STM monitoring for surveillance. Increasingly, MRI is being used to characterize ovarian lesions that are indeterminate at US or CT. The future of STM testing involves development of "liquid biopsies," in which plasma samples are analyzed for evidence of tumors, including circulating tumor DNA or tumor cells and tumor micro-RNA. When combined with traditional imaging techniques, liquid biopsies may lead to earlier diagnosis and improved survival. An invited commentary by Shinagare is available online. ©RSNA, 2021.

Second Malignancies after Radiation Therapy: Update on Pathogenesis and Cross-sectional Imaging Findings.

A wide spectrum of second cancers occur as late complications of radiation therapy (RT) used to treat various malignancies. In addition to the type and dose of radiation, lifestyle, environmental, and genetic factors are important to the development of second malignancies in cancer survivors. Typically, RT-induced malignancies (RTIMs) are biologically aggressive cancers with a variable period of 5-10 years for hematologic malignancies and 10-60 years for solid tumors between RT and the development of the second cancer. Although carcinomas and leukemias commonly develop after low-dose RT, sarcomas occur in tissues or organs that receive high-dose RT. Angiosarcomas and unclassified pleomorphic sarcomas are the two most common RT-associated sarcomas; other sarcomas include malignant peripheral nerve sheath tumors, leiomyosarcomas, osteosarcomas, chondrosarcomas, and dedifferentiated or pleomorphic liposarcomas. Select RTIMs show tumor genetic characteristics that allow accurate diagnosis. Nearly all cutaneous angiosarcomas after RT for breast cancer and 90% of RT-associated malignant peripheral nerve sheath tumors are characterized by MYC gene amplifications and loss of H3 K27me3 expression, respectively. Classic papillary thyroid carcinomas that develop after RT frequently harbor RET/PTC rearrangements and have a favorable prognosis, despite their advanced stage at patient presentation. Select RTIMs demonstrate characteristic imaging findings and typically develop in the prior radiation field. Imaging is essential to early diagnosis, characterization, localization, and staging of RTIMs. Familiarity of radiologists with the diverse spectrum of RTIMs is essential for early diagnosis and optimal management. An invited commentary by Shapiro is available online. ©RSNA, 2021.

Posttransplant Lymphoproliferative Disorder Status Post-Solid Organ Transplant Presenting to the Emergency Department: Single Institute Experience.

OBJECTIVE: The objective of this study was to evaluate the clinical, laboratory, imaging, and pathology findings associated with emergency department presentations of posttransplant lymphoproliferative disorder (PTLD) after solid organ transplant (SOT). METHODS: Fifteen patients presenting to a single tertiary care center between 2004 and 2019 with PTLD after SOT were identified from a pathology database. Twelve patients presenting through the emergency department were included in the study. Demographic, clinical, imaging, pathology, treatment, and outcome data were reviewed. RESULTS: Among this 12 patient cohort (7 men; mean age, 44.2 years), transplant history included 4 combined kidney/pancreas, 4 kidney, 2 liver, 1 cardiac, and 1 lung. Mean time from transplant to diagnosis was 7.6 years. Posttransplant lymphoproliferative disorder was identified on initial computed tomography scans in 10 of 12 patients. The most common sites for PTLD development were the gastrointestinal tract (4/12) and liver (3/12). Outcomes included resolution of PTLD in 9 of 12 patients, with 3 patients dying within 6 months of diagnosis. CONCLUSIONS: Posttransplant lymphoproliferative disorder is a serious consequence of solid organ transplantation that can present in various locations and with varied symptomatology in the emergency setting. Other posttransplant complications may present similarly including chronic rejection and infection. Posttransplant lymphoproliferative disorder should be considered in SOT patients presenting with worsening abdominal pain or constitutional symptoms, even with normal laboratory workup.

The Past, Present, and Future (Liquid Biopsy) of Serum Tumor Markers in Lung Cancer: A Primer for the Radiologist.

ABSTRACT: Lung cancer continues to be a major cause of death throughout the world. The ability to both accurately diagnose lung cancer in its early stages and monitor response to treatment is essential to reducing the morbidity and mortality associated with the disease. Serum tumor markers have been identified as potential biomarkers that may aid in lung cancer diagnosis and surveillance. These markers, when combined with cross-sectional imaging, may result in more robust screening and surveillance protocols. The future role of serum tumor markers in lung cancer includes the advancement of "liquid biopsies," in which peripheral blood samples are analyzed for tumor components without the need for a tissue biopsy.

Evaluation of equivocal small cystic pancreatic lesions with spectral-detector computed tomography.

BACKGROUND: Evaluation of small cystic lesions of the pancreas remains a challenging task, as due to their size appearance can be rather hypodense than clearly fluid-filled. PURPOSE: To evaluate whether additional information provided by novel dual-layer spectral-detector computed tomography (SDCT) imaging can improve assessment of these lesions. MATERIAL AND METHODS: For this retrospective study, we reviewed reports of 1192 contrast-enhanced portal-venous phase SDCT scans of the abdomen conducted between May 2017 and January 2019. On basis of the radiological report 25 small (≤1.5 cm) cystic pancreatic lesions in 22 patients were identified, in which additional short-term follow-up imaging was recommended to confirm/clarify cystic nature. Conventional images (CI) and spectral images (SI) including virtual-monoenergetic images at 40 keV (VMI), iodine-density and iodine-overlay images were reconstructed. Two readers indicated lesion conspicuity and confidence for presence of cystic nature on three-point scales. First, solely CI were evaluated, while in a second reading after a four-week interval, the combination of CI and corresponding SI were reviewed. Quantitatively, ROI-based mean attenuation was measured in CI and VMI. RESULTS: In the subjective reading, SI significantly improved lesion conspicuity (CI 2 [1-2], SI 3 [2-3], P < 0.001) and confidence regarding presence of cystic nature (CI 2 [1-2], SI 3 [3-3], P < 0.001). Inter-observer agreement depicted by intraclass correlation coefficient improved considerably from 0.51 with only CI to 0.85 when the combination with SI was used. Further, VMI displayed significantly higher signal-to-noise (CI 1.2 ± 0.8, VMI 3.2 ± 1.8, P < 0.001) and contrast-to-noise ratios (CI 2.6 ± 0.8, VMI 4.7 ± 1.9). CONCLUSION: Compared to CI alone, combination with SI significantly improves visualization and confidence in evaluation of small equivocal cystic pancreatic lesions.

Considerations in imaging interpretations for colitis in critically ill patients during the COVID-19 era.

OBJECTIVE: The study aims to demonstrate risk factors for colitis in intensive care unit patients with and without coronavirus disease 2019 (COVID-19). METHODS: Retrospective review was performed to identify intensive care unit (ICU) patients with the diagnosis of COVID-19 with computed tomography (CT) between March 20 and December 31, 2020. ICU patients without COVID-19 diagnosis with CT between March 20 and May 10, 2020 were also identified. CT image findings of colitis or terminal ileitis as well as supportive treatment including ventilator, vasopressors, or extracorporeal membrane oxygenation (ECMO) were recorded. Statistical analysis was performed to determine if clinical factors differed in patients with and without positive CT finding. RESULTS: Total 61 ICU patients were selected, including 32 (52%) COVID-19-positive patients and 29 (48%) non-COVID-19 patients. CT findings of colitis or terminal ileitis were identified in 27 patients (44%). Seventy-four percent of the patients with positive CT findings (20/27) received supportive therapies prior to CT, while 56% of the patients without abnormal CT findings (19/34) received supportive therapies. Vasopressor treatment was significantly associated with development of colitis and/or terminal ileitis (p = 0.04) and COVID-19 status was not significantly different between these groups (p = 0.07). CONCLUSIONS: In our study, there was significant correlation between prior vasopressor therapy and imaging findings of colitis or terminal ileitis in ICU patients, independent of COVID-19 status. Our observation raises a possibility that the reported COVID-19-related severe gastrointestinal complications and potential poor outcome could have been confounded by underlying severe critically ill status, and warrants a caution in diagnosis of gastrointestinal complication.

Diagnostic utility of computed tomography in patients presenting to the emergency department with unintended weight loss.

PURPOSE: Unintended weight loss (UWL) is a common presenting symptom in the emergency department (ED) with several etiologies. Our study looks to evaluate the diagnostic utility of computed tomography (CT) in the evaluation of UWL in the ED. METHODS: We identified all patients who underwent CT of the chest, abdomen, or pelvis in the ED at our institution for the diagnosis of UWL from 2004 to 2020 and retrospectively reviewed their clinical history and imaging. CT findings were organized into 4 types: (1) definite cause for UWL identified, (2) possible findings for UWL, (3) incidental findings unrelated to UWL, and (4) normal scan. Associations between clinical and laboratory findings with positive CT scans were also examined. RESULTS: One hundred seventy-three eligible patients were identified; 40 patients were excluded due to history of malignancy or inadequate follow-up. One hundred thirty-three patients were included in the final cohort. Overall, the most common causes of UWL were non-malignant gastrointestinal (GI) conditions (n = 41, 30%) and cancer (n = 30, 23%). True-positive CT findings were identified in 48.8% of patients (65/133). Elevated white blood cell counts (p = <0.0001) and physical exam abnormalities (p = 0.02) were both significantly associated with CT abnormalities. CONCLUSION: The use of CT scanning in the evaluation of UWL in the ED yielded a diagnosis in approximately half of all cases, indicating good diagnostic value. The most common causes of UWL were non-malignant GI conditions and cancer in this cohort.

The Role of Imaging and Systemic Treatments in Myeloma: A Primer for Radiologists.

OBJECTIVE. The purpose of this article is to provide an up-to-date guide for radiologists on imaging and systemic therapies in myeloma and related conditions, with a focus on radiologic findings for diagnosis and treatment response assessment. CONCLUSION. Knowledge of the unique imaging presentations of myeloma is highly useful for radiologists. An understanding of the utility of different imaging modalities and the systemic therapies used in multiple myeloma is also critical in the realm of oncologic imaging.

Hemophagocytic Lymphohistiocytosis: A Primer for Radiologists.

OBJECTIVE. The purpose of this article is to provide for radiologists an overview of the radiologic, clinical, and pathologic features of hemophagocytic lymphohistiocytosis. CONCLUSION. Hemophagocytic lymphohistiocytosis is a rare, life-threatening syndrome characterized by abnormal, excessive activation of the immune system. Imaging plays an important role in determining the extent of involvement of hemophagocytic lymphohistiocytosis. Knowledge of this entity, including its imaging, clinical, and pathologic findings, is critical to facilitate timely diagnosis.

Clinical, Imaging Findings, Responses, and Outcomes of Patients With Classical Hodgkin Lymphoma and Non-Hodgkin Lymphoma Undergoing Immune Checkpoint Inhibitor Therapy: A Single-Institution Experience.

OBJECTIVE: The aim of the study was to study clinical, imaging findings, response patterns, and immune-related adverse events in classical Hodgkin lymphoma (cHL) and non-Hodgkin lymphoma (NHL) patients treated with immune checkpoint inhibitors (ICIs). METHODS: A retrospective search was performed to identify patients with relapsed/refractory cHL and NHL treated with ICIs from 2015 to 2019. Clinical and laboratory data were collected. Imaging studies were reviewed for treatment response and immune-related adverse events. RESULTS: Ten patients with relapsed/refractory cHL (median age, 41 years) and 14 patients with relapsed/refractory NHL (median age, 61 years) were identified. Overall response rate was 70% for cHL patients. None of the NHL patients demonstrated complete or partial response. One case of hyperprogression and one case with atypical response were radiologically detected in cHL patients. Hypothyroidism requiring treatment occurred in 2 (20%) of 10 cHL patients, one of which had imaging correlate. Of 14 NHL patients, 1 (7%) had radiologic evidence of pneumonitis and 1 (7%) had colitis. CONCLUSIONS: This single-institution observational study demonstrated that overall response rate was higher in patients with cHL undergoing ICI. Immune checkpoint inhibitor therapy has unique response patterns and toxicities in both cHL and NHL patients that radiologists should keep in mind.

A pictorial review of non-traumatic adrenergic crisis.

Non-traumatic adrenal crisis is a rare but critical diagnosis to make in emergency settings due to grave consequences. Various pathologies can present as acute crisis, such as spectrum of endocrine imbalance, ranging from catecholamine excess in pheochromocytomas to acute adrenal insufficiency related to glandular dysfunction. Critical manifestations may be due to structural causes related to adrenal hemorrhage, especially when they are bilateral. Oncological complications such as vascular invasion, tumoral bleed, rupture, and hormonal dysfunction can occur. Due to non-specific clinical presentation, these conditions may come as a surprise on imaging performed for other reasons. Recognition of these imaging findings is critical for appropriate patient management. Although there are few articles discussing non-traumatic emergencies in literature, this review is inclusive of all possible etiologies, thus provides a holistic approach and insight into each situation. Specific imaging approach is needed to tailor the diagnosis. This article will also discuss about the advanced imaging techniques that will complement diagnosis.

Clinical, imaging, endoscopic findings, and management of patients with CMV colitis: a single-institute experience.

PURPOSE: To evaluate clinical, laboratory, imaging, endoscopic findings, treatment, and outcomes of patients with CMV colitis. METHODS: The electronic medical records of 652 patients who had an impression of colitis of unspecified etiology via endoscopic findings between 2011 and 2019 were retrospectively reviewed. There were 9 patients with biopsy-proven CMV colitis and associated CT imaging performed within 1 month of diagnosis. Demographic data, past medical history, symptoms, laboratory, imaging, endoscopic and biopsy findings, colitis-related adverse events, treatment, and management were recorded. RESULTS: Within the group of 9 patients (2 men; median age, 60 years), all were in an immunosuppressed state (8/9 on immunosuppressive medication regimen and 1/9 with untreated AIDS). Presenting symptoms of CMV colitis included bloody stools (9/9), abdominal pain (7/9), and diarrhea (7/9). The most common imaging findings were pericolonic stranding (9/9) and bowel wall thickening (9/9). Endoscopic evaluation noted inflammation (9/9), ulceration (9/9), and erythema (8/9) as the most prevalent impressions. As determined by both imaging and endoscopy, the sigmoid colon was most commonly affected. Patients were treated with valganciclovir alone (3/9) or ganciclovir followed by valganciclovir (6/9). Outcomes included perforated colon (1/9), persistent colitis (3/9), discharge to hospice (1/9), and resolution (4/9). CONCLUSIONS: CMV colitis is generally associated with an immunosuppressed state. Imaging and endoscopic findings can mimic inflammatory, ischemic, and infectious colitides. However, CMV colitis should be included in the differential diagnosis in immunocompromised adults who present to emergency department with bloody stools, acute abdominal pain or diarrhea, and have bowel wall thickening and pericolonic stranding on imaging.

Myocarditis associated with immune checkpoint inhibitor therapy: a case report of three patients.

Immune checkpoint inhibitor (ICI)-associated myocarditis is a rare but potentially fatal complication associated with development of other immune-related adverse events (irAEs). Troponin levels, ECG, echocardiography, and cardiac MR can assist with the diagnosis of this rare albeit serious adverse effect related to immunotherapy. In this case report, we present the clinical and radiological features of myocarditis in three patients presenting with acute symptoms while receiving therapy with ICIs. Blood troponin and ECG were abnormal in all three myocarditis cases. Initial echocardiography was abnormal in two patients with reduced left ventricular ejection fraction (LVEF). The third patient demonstrated an initially normal LVEF with subsequent transient decrease in LVEF on follow-up echocardiogram. Cardiac MR was abnormal in three cases with areas of mid-myocardial/epicardial delayed enhancement. All patients experienced additional irAEs. One patient died shortly after myocarditis diagnosis, one was made comfort care due to poor clinical status, and one improved with steroid treatment.

Quantifying the decrease in emergency department imaging utilization during the COVID-19 pandemic at a multicenter healthcare system in Ohio.

PURPOSE: To illustrate the change in emergency department (ED) imaging utilization at a multicenter health system in the state of Ohio during the COVID-19 pandemic. METHODS: A retrospective observational study was conducted assessing ED imaging volumes between March 1, 2020, and May 11, 2020, during the COVID-19 crisis. A rolling 7-day total value was used for volume tracking and comparison. Total imaging utilization in the ED was compared with new COVID-19 cases in our region. Utilization was first categorized by modality and then by plain films and computed tomography (CT) scans grouped by body part. CT imaging of the chest was specifically investigated by assessing both CT chest only exams and CT chest, abdomen, and pelvis (C/A/P) exams. Ultimately, matching pair-wise statistical analysis of exam volumes was performed to assess significance of volume change. RESULTS: Our multicenter health system experienced a 46% drop in imaging utilization (p < 0.0001) during the pandemic. Matching pair-wise analysis showed a statistically significant volume decrease by each modality and body part. The exceptions were non-contrast chest CT, which increased (p = 0.0053), and non-trauma C/A/P CT, which did not show a statistically significant volume change (p = 0.0633). CONCLUSION: ED imaging utilization trends revealed through actual health system data will help inform evidence-based decisions for more accurate volume predictions and therefore institutional preparedness for current and future pandemics.