The Short and Long of COVID-19: A Review of Acute and Chronic Radiologic Pulmonary Manifestations of SARS-2-CoV and Their Clinical Significance.

Coronavirus disease 2019 (COVID-19) pneumonia has had catastrophic effects worldwide. Radiology, in particular computed tomography (CT) imaging, has proven to be valuable in the diagnosis, prognostication, and longitudinal assessment of those diagnosed with COVID-19 pneumonia. This article will review acute and chronic pulmonary radiologic manifestations of COVID-19 pneumonia with an emphasis on CT and also highlighting histopathology, relevant clinical details, and some notable challenges when interpreting the literature.

Comparative Evaluation of Choose Your Own Adventure and Traditional Linear Case Formats in Radiology Small Group Teaching.

RATIONALE AND OBJECTIVES: We aim to compare Choose Your Own Adventure (CYOA) presentation format with linear case format as educational methods for teaching a radiology small group session to medical students. MATERIALS AND METHODS: A radiology small group session was held for preclinical second-year medical students in the pulmonary course, whereby eight classrooms of students and eight radiology facilitators were each randomized to do either the linear case format or the nonlinear CYOA presentation format. All students in attendance were administered a survey at the end of the session, which assessed students' perceptions using five-point Likert-type questions. The survey also contained a four-question knowledge quiz on chest radiology. The facilitators were administered a qualitative survey as well. Between-group analyses were performed using Student's t-test. RESULTS: Of the 144 students who attended the small group sessions, 143 students completed the survey (99.3%). The CYOA format group reported significantly greater engagement in the cases (4.5 ± 0.7 vs. 3.8 ± 0.7, p < 0.001), satisfaction with the format (4.6 ± 0.6 vs. 3.7 ± 0.9, p < 0.001), and enhancement of clinical decision making skills (4.5 ± 0.6 vs. 3.5 ± 0.9, p < 0.001). The linear format group reported a greater role for the facilitator to add value (4.6 ± 0.5 vs. 4.3 ± 1.1, p = 0.033). There was no significant difference between groups in performance on the knowledge quiz. CONCLUSION: Medical students reported higher satisfaction, engagement, and enhanced clinical decision making skills with the CYOA presentation method compared to linear case format for radiology small group learning.

Management Strategies for Patients Presenting With Symptomatic Lymphadenopathy and Breast Edema After Recent COVID-19 Vaccination.

Ipsilateral axillary lymphadenopathy is a well-documented finding associated with COVID-19 vaccination. Varying guidelines have been published for the management of asymptomatic patients who have a history of recent vaccination and present with incidental lymphadenopathy at screening mammography. Some experts recommend follow-up imaging, and others suggest that clinical management, rather than repeat imaging or biopsy, is appropriate. Symptomatic patients with lymphadenopathy and/or additional abnormal imaging findings should be treated differently depending on risk factors and clinical scenarios. Although ipsilateral lymphadenopathy is well documented, ipsilateral breast edema after COVID-19 vaccination has been rarely reported. The combination of ipsilateral lymphadenopathy and diffuse breast edema after COVID-19 vaccination presents a clinical management challenge because edema can obscure underlying abnormalities at imaging. For symptomatic patients with lymphadenopathy and associated breast parenchymal abnormality, prompt action is appropriate, including diagnostic evaluation and consideration of tissue sampling. This approach may prevent delays in diagnosis and treatment of patients with malignancy masked by symptoms from the vaccination.

Delayed-Phase Enhancement for Evaluation of Malignant Pleural Mesothelioma on Computed Tomography: A Prospective Cohort Study.

BACKGROUND: Radiologic assessment of malignant pleural mesothelioma (MPM) on computed tomography (CT) imaging can be limited by similar attenuations of MPM and adjacent tissues. This can result in inaccuracies in defining the presence and extent of pleural tumor burden. We hypothesized that increasing the time delay for pleural enhancement will optimize discrimination between MPM and noncancerous tissues on CT. Here we conduct a prospective observational study to determine the optimal time delay for imaging MPM on CT. PATIENTS AND METHODS: Adult MPM patients (n = 15) were enrolled in this prospective exploratory imaging trial. Patients with < 1 cm MPM thickness, prior pleurectomy, pleurodesis, pleural radiotherapy, or antiangiogenic therapy were excluded. All patients underwent a dynamically-enhanced CT with multiple time delays (0 - 10 minutes) after intravenous contrast administration. Tumor tissue attenuation was measured at each phase of enhancement. A qualitative assessment of tumor enhancement kinetics was also performed. The optimal phase of enhancement based on qualitative lesion conspicuity and quantitative tumor enhancement was then compared. RESULTS: MPM tumor enhancement was quantitatively and qualitatively increased at time delays beyond the conventional time delay for thoracic CT imaging (40-60 seconds). Patient tumor enhancement kinetics, displayed as the fraction of maximal tumor tissue attenuation as a function of time, revealed an optimal time delay of 230 to 300 seconds after intravenous contrast administration. There was an association between degree of tumor enhancement and subjective lesion conspicuity. CONCLUSION: Optimal MPM contrast enhancement occurs at a later phase than typically acquired with conventional thoracic CT imaging.

Harnessing Augmented Reality and CT to Teach First-Year Medical Students Head and Neck Anatomy.

RATIONALE AND OBJECTIVES: Three-dimensional (3D) visualization has been shown to benefit new generations of medical students and physicians-in-training in a variety of contexts. However, there is limited research directly comparing student performance after using 3D tools to those using two-dimensional (2D) screens. MATERIALS AND METHODS: A CT was performed on a donated cadaver and a 3D CT hologram was created. A total of 30 first-year medical students were randomly assigned into two groups to review head and neck anatomy in a teaching session that incorporated CT. The first group used an augmented reality headset, while the second group used a laptop screen. The students were administered a five-question anatomy test before and after the session. Two-tailed t-tests were used for statistical comparison of pretest and posttest performance within and between groups. A feedback survey was distributed for qualitative data. RESULTS: Pretest vs. posttest comparison of average percentage of questions answered correctly demonstrated both groups showing significant in-group improvement (p < 0.05), from 59% to 95% in the augmented reality group, and from 57% to 80% in the screen group. Between-group analysis indicated that posttest performance was significantly better in the augmented reality group (p = 0.022, effect size = 0.73). CONCLUSION: Immersive 3D visualization has the potential to improve short-term anatomic recall in the head and neck compared to traditional 2D screen-based review, as well as engage millennial learners to learn better in anatomy laboratory. Our findings may reflect additional benefit gained from the stereoscopic depth cues present in augmented reality-based visualization.

First-Year Radiology Residents Teaching Anatomy to First-Year Medical Students: A Symbiotic Relationship.

OBJECTIVES: Our institution has developed an educational program in which first-year radiology residents teach first-year medical students during gross anatomy laboratory sessions. The purpose of this study is to assess the impact of this program on medical student knowledge and perceptions of radiology, and on resident attitudes toward teaching. MATERIALS AND METHODS: First-year resident pairs taught small groups of medical students during weekly 15-minute interactive sessions, and were evaluated on teaching skills by senior residents. A survey about attitudes toward radiology and a knowledge quiz were sent to the medical students, and a survey about attitudes toward teaching was sent to the first-year radiology residents, both pre-course and post-course. RESULTS: Students' radiology knowledge significantly increased between the pre-course and post-course survey across all categories tested (P < 0.001). Additionally, there were significant improvements in terms of students' confidence in radiologic anatomy skills, perceived importance of radiology for medical training, familiarity with the field of radiology, and perception that radiologists are friendly (P < 0.001). Radiology residents felt more confident in their teaching proficiency (P < 0.001) by the conclusion of the course. CONCLUSIONS: Resident-led small-group teaching sessions during anatomy laboratory are mutually beneficial for medical students and radiology residents. The program also allows radiology residents to be exposed early on in residency to teaching and academic medicine.

Patient-Centered and Specialty-Specific Case Work-Up: An Effective Method for Teaching Appropriateness of Imaging to Medical Students.

RATIONALE AND OBJECTIVES: Our institution has developed a mini-course program within the diagnostic radiology elective curriculum that promotes active learning, using patient cases specifically tailored to students' future specialties. The purpose of this study is to evaluate the effectiveness of this mini-course on medical student knowledge of imaging appropriateness and attitude toward radiologist consultation. MATERIALS AND METHODS: During each month-long radiology elective course, students were divided into teams of up to four students based on their specialty interest and assigned recent patient cases with imaging findings relevant to their specialties. The students researched their customized patient cases, integrated pertinent clinical and imaging findings, and presented their findings in a final preceptor-led session. A five-point Likert-type item preprogram and postprogram survey assessing knowledge of imaging appropriateness and attitude toward radiologist consultation was sent to the enrolled medical students. RESULTS: Out of 36 medical students, 33 (92%) completed the preprogram survey and 31 (86%) completed the postprogram survey. Students reported improved confidence in knowledge of imaging appropriateness, such as indications for intravenous contrast (p < 0.0005) and oral contrast (p < 0.0005). Furthermore, students reported an improved understanding of how to utilize radiologists (p < 0.005) and how to provide pertinent clinical historical information when requesting a radiology exam (p < 0.0005). Students reported that researching the patient's historical and clinical information in conjunction with the radiology images made them more invested in the case. CONCLUSION: Assigning customized patient cases to medical students on diagnostic radiology elective, tailored to their future specialties, is an effective and active way to teach imaging appropriateness and to improve attitudes toward radiologist consultation.

Thoracic Imaging of Non-Small Cell Lung Cancer Treated With Anti-programmed Death Receptor-1 Therapy.

PURPOSE: Treatment with anti-programmed death receptor-1 (PD-1) therapeutics can lead to unconventional responses and side effect profiles due to their potentiating effects on the immune system. Here we evaluate the radiologic manifestations of anti-PD-1 therapy in the chest in patients with non-small cell lung cancer (NSCLC) receiving anti-PD-1 therapy. MATERIALS AND METHODS: A retrospective review of real-world clinical practice was conducted of all the patients with NSCLC receiving anti-PD-1 therapy at our institution between 2013 and 2016. All patients without adequate clinical or radiologic follow-up data in the electronic medical records were excluded. Imaging examinations for all patients deemed by their thoracic oncologists to have radiologic pseudoprogression or therapy-associated pneumonitis were reviewed by experienced thoracic radiologists. RESULTS: A total of 166 patients with NSCLC had available clinical and imaging data for retrospective review. Of these patients, 4 (2%) were considered to have radiologic pseudoprogression, 3 of which manifested as increased tumor size and 1 of which manifested with new lesions. A total of 5 patients (3%) were clinically deemed to have pneumonitis attributable to anti-PD-1 therapy, 4 of which had radiologic manifestations on computed tomography. CONCLUSION: Radiologic pseudoprogression and drug-induced pneumonitis are uncommon but important manifestations of anti-PD-1 therapy on thoracic imaging.

Impact of Early Radiology Research Experiences on Medical Student Perceptions of Radiology and Research.

RATIONALE AND OBJECTIVES: To promote opportunities for medical students to gain early exposure to radiology and research, our institution has initiated programs which fund summer radiology research projects for rising second-year medical students. This study assesses the impact of these faculty-mentored summer research experiences on medical student perceptions of radiology and research, in terms of both knowledge and interest. MATERIALS AND METHODS: A voluntary, anonymous survey was administered to students both before and after the summer research period. Both the pre-program survey and post-program survey included 7-point Likert-scale questions (1 = strongly disagree; 7 = strongly agree) to evaluate students' perceptions about research and students' perceptions about radiology as a specialty. Faculty mentors were sent an analogous post-program survey that included an evaluation of their student's research skills. RESULTS: The surveys were completed by 9 of 11 students and 10 of 11 mentors. Students' perceived knowledge of radiology as a specialty improved (P = 0.02) between the pre-program survey and post-program survey. Similarly, there was an increase in students' perceived knowledge of research skills (P = 0.02) between the pre-program survey and post-program survey, with student ratings of research skills consistent with those of mentors. High student interest in both radiology and research was maintained over the course of the program. CONCLUSION: Our pilot study suggests that summer research experiences can improve knowledge of radiology and research among medical students. Continued evaluation of this annual program will allow us to enhance the benefit to medical students and thereby bolster interest in academic radiology.

Radiologic Pseudoprogression during Anti-PD-1 Therapy for Advanced Non-Small Cell Lung Cancer.

INTRODUCTION: Anti-programmed cell death protein 1 (PD-1) therapy can lead to unconventional tumor responses, including radiologic pseudoprogression. Here we have determined the real-world incidence of radiologic pseudoprogression in advanced NSCLC and compared radiologic response criteria for assessment of disease response. METHODS: The electronic medical records of all patients with NSCLC who were receiving anti-PD-1 therapy at our institution over a 3-year period were retrospectively reviewed, and patients with clinically suspected radiologic pseudoprogression were identified. Patients without available follow-up imaging or clinical data were excluded. Imaging examinations were then analyzed to determine whether progression was confirmed on subsequent reimaging. Assessments of tumor response by the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1 (RECIST 1.1), the unidimensional immune-related response criteria (iRRC), and the iRECIST criteria for all patients were performed and compared. RESULTS: A total of 228 consecutive patients began receiving anti-PD-1 therapy over a 3-year period. Of the 166 of these patients who were evaluable, most (80%) received nivolumab. Fifteen patients (9%) were clinically suspected of having radiologic pseudoprogression on account of tumor enlargement and/or development of new lesions on computed tomography images during the first 4 to 6 weeks of therapy, and they continued receiving anti-PD-1 therapy. Three of these patients (2%) demonstrated evidence of radiologic pseudoprogression at first reimaging. The iRRC and immune RECIST criteria were more accurate in classifying radiologic pseudoprogression as nonprogression; none of the three cases were deemed progression by the iRRC or immune RECIST, whereas all three cases were determined to be progression according to the Response Evaluation Criteria in Solid Tumors, version 1.1. CONCLUSIONS: Radiologic pseudoprogression is a clinical challenge but an uncommon occurrence in patients with NSCLC who are receiving anti-PD-1 therapy.

Limited Utility of Pulmonary Nodule Risk Calculators for Managing Large Nodules.

RATIONALE AND OBJECTIVES: The optimal management of large pulmonary nodules, at higher risk for lung cancer, has not been determined, and it remains unclear as to which patients should undergo follow-up imaging vs invasive tissue diagnosis via biopsy or surgical resection. MATERIALS AND METHODS: Through search of radiology reports, 86 nodules from our institution were identified using the inclusion criterion of solid nodules measuring greater than 8mm. We evaluated these nodules with a number of risk prediction calculators, including the Brock University model, and compared these against the proven diagnosis. RESULTS: Of 86 nodules, 59 (69%) nodules were malignant. The most accurate predictive model, the Brock University calculator, underestimated the risk for this group at 33%. At its optimal threshold, this model had a positive predictive value of 81% and negative predictive value of 53%. Notwithstanding the low negative predictive value, the positive predictive value was no better than patients clinically selected for biopsy (86% of biopsies were malignant). CONCLUSION: Existing nodule risk prediction calculators are of limited usage in guiding the management of large pulmonary nodules. At present, the accuracy of these models in this setting is inferior to expert clinical judgment, and future work is needed to develop management algorithms for higher-risk nodules.

Imaging of Intrathoracic Paragangliomas.

Intrathoracic paragangliomas are uncommon and only represent 1%-2% of paragangliomas. They are most commonly found in mediastinal compartments (aortopulmonary window or posterior mediastinum). Computed tomography, magnetic resonance, and specific nuclear medicine radiotracers are routinely used to characterize these lesions and help exclude other more common conditions. Selective angiography is currently used for preoperative embolization and mapping of the vascular supply before surgical resection, rather than for diagnostic purposes alone.

The value of delayed phase enhanced imaging in malignant pleural mesothelioma.

BACKGROUND: Cross-sectional imaging of malignant pleural mesothelioma (MPM) can underestimate the presence of local tumor invasion. Since accurate staging is vital optimal choice of therapy, techniques that optimize pleural imaging are needed. Here we estimate the optimal timing of MPM enhancement on magnetic resonance imaging (MRI). METHODS: All MPM patients with intravenous (IV) contrast enhanced staging MRI between 2000-2016 at our institution were retrospectively selected for image analysis. Patients with incomplete imaging protocol and maximum pleural tumor thickness <1 cm were excluded. Quantitative measurements of tumor signal intensity were obtained on pre-contrast and post-contrast phases where MRI acquisition parameters were fixed. Using best-fit model curves, predicted maximum time points of enhancement were determined using a simulation of predicted values. Additionally, a qualitative assessment of tumor conspicuity was performed at all IV contrast time delays imaged. A statistical analysis assessed for correlation between qualitative lesion conspicuity and quantitative tumor enhancement. RESULTS: Of the 42 MPM patients who had undergone staging MRI during the study period, 12 patients met the study criteria. Peak tumor enhancement was between 150 and 300 sec following IV contrast administration. Within this time window, 80% of patients are projected to have reached >80%, >85%, and >90% peak tumor enhancement. There was a statistically significant correlation between increasing tumor enhancement and subjective lesion conspicuity. CONCLUSIONS: Optimal MPM enhancement on MRI likely occurs at a time delay between 2.5-5 min following IV contrast administration. Further study of delayed phase enhancement of MPM with dynamic contrast enhanced MRI is warranted.

Pulmonary Tuberculosis: Role of Radiology in Diagnosis and Management.

Tuberculosis is a public health problem worldwide, including in the United States-particularly among immunocompromised patients and other high-risk groups. Tuberculosis manifests in active and latent forms. Active disease can occur as primary tuberculosis, developing shortly after infection, or postprimary tuberculosis, developing after a long period of latent infection. Primary tuberculosis occurs most commonly in children and immunocompromised patients, who present with lymphadenopathy, pulmonary consolidation, and pleural effusion. Postprimary tuberculosis may manifest with cavities, consolidations, and centrilobular nodules. Miliary tuberculosis refers to hematogenously disseminated disease that is more commonly seen in immunocompromised patients, who present with miliary lung nodules and multiorgan involvement. The principal means of testing for active tuberculosis is sputum analysis, including smear, culture, and nucleic acid amplification testing. Imaging findings, particularly the presence of cavitation, can affect treatment decisions, such as the duration of therapy. Latent tuberculosis is an asymptomatic infection that can lead to postprimary tuberculosis in the future. Patients who are suspected of having latent tuberculosis may undergo targeted testing with a tuberculin skin test or interferon-γ release assay. Chest radiographs are used to stratify for risk and to assess for asymptomatic active disease. Sequelae of previous tuberculosis that is now inactive manifest characteristically as fibronodular opacities in the apical and upper lung zones. Stability of radiographic findings for 6 months distinguishes inactive from active disease. Nontuberculous mycobacterial disease can sometimes mimic the findings of active tuberculosis, and laboratory confirmation is required to make the distinction. Familiarity with the imaging, clinical, and laboratory features of tuberculosis is important for diagnosis and management. ©RSNA, 2017.

Pathology of the Trachea and Central Bronchi.

A wide variety of disorders can affect the trachea and central bronchi. Computed tomography is the imaging modality of choice in the evaluation of tracheobronchial disease. Tracheobronchial abnormalities are sometimes incidentally detected on routine imaging or when imaging is performed for another reason. Abnormalities of the tracheobronchial tree, however, can be easily missed because they can be subtle. Furthermore, because symptoms in patients with tracheobronchial disorders often overlap symptoms of lung disease, radiologists may focus their attention on the lungs and overlook the tracheobronchial tree. In this article, we review a wide range of tracheobronchial diseases with emphasis on their computed tomographic appearances.

CT Dose Reduction Workshop: An Active Educational Experience.

PURPOSE: Improving patient safety by minimizing CT radiation dose, while maintaining diagnostic image quality, has become an important skill in diagnostic radiology. The aim of this study was to examine the value of an educational workshop for optimizing CT protocols in an academic department, and to assess its impact on resident education. METHODS: The CT Dose Reduction Workshop met monthly for 1 year, to teach and implement dose reduction strategies. Changes were made to CT protocols through group consensus while participants kept up to date with current literature. A survey was sent to 48 radiology residents and 32 attending radiologists in the department, including both participants and nonparticipants, after completion of the workshop, to assess its utility. The survey used a 5-point Likert-type scale. Average doses for a specific CT protocol before and after the workshop were compared. RESULTS: About 80% of respondents agreed or strongly agreed that the workshop was essential. Workshop participants expressed greater confidence in their knowledge of dose reduction techniques, with a mean score of 3.74 (95% confidence interval, 3.35-4.13), compared with nonparticipants, who had a mean score of 3.00 (95% confidence interval, 2.64-3.36) (P < .01). Dose reductions were established across numerous CT protocols. For instance, the average total dose-length product in renal mass protocol CT examinations decreased by 54% (P < .0001). CONCLUSIONS: A CT dose reduction workshop increases participants' confidence in knowledge of dose reduction techniques, fosters a culture of safety and quality improvement in the department, and reduces radiation dose to patients.

The Effect of Needle Gauge on the Risk of Pneumothorax and Chest Tube Placement After Percutaneous Computed Tomographic (CT)-Guided Lung Biopsy.

BACKGROUND: The aim of this study was to evaluate the effect of coaxial guide needle gauge (18 vs. 19 gauge) on the risk of pneumothorax and chest tube placement after CT-guided lung biopsy. METHODS: Imaging records of all patients who had undergone CT-guided lung biopsies at our institution from March 1, 2006 to December 9, 2010 were retrospectively reviewed. Univariate and multivariate logistic regression analyses were performed to assess the effect of various patient-, lesion-, and procedure-related variables on subsequent pneumothorax and chest tube placement rates. RESULTS: The study included 4262 biopsies (2304 with 18-gauge and 1958 with 19-gauge coaxial guide needles) in 3917 patients. The rates of pneumothorax and chest tube placement were 30.2 and 15%, respectively. Pneumothorax occurred in 35% of procedures performed with 18-gauge needles and in 24.5% of procedures performed with 19-gauge needles (p < 0.0001). Chest tube insertion occurred in 16.7% of procedures performed with 18-gauge needles and in 13.1% of procedures performed with 19-gauge needles (p = 0.0011). Multivariate logistic regression models demonstrated that the use of an 18-gauge needle was associated with a higher rate of pneumothorax (p < 0.0001) and chest tube placement (p = 0.0003). The following factors were also associated with higher rates of pneumothorax and chest tube placement: older age, emphysema, greater number of pleural surfaces crossed, and a longer biopsy needle path length. CONCLUSIONS: The use of a 19-gauge coaxial guide needle significantly decreases the risk of pneumothorax and chest tube placement compared with an 18-guage needle.