Viral Pneumonias.

Viral pneumonia is usually community acquired and caused by influenza, parainfluenza, respiratory syncytial virus, human metapneumovirus, and adenovirus. Many of these infections are airway centric and chest imaging demonstrates bronchiolitis and bronchopneumonia, With the exception of adenovirus infections, the presence of lobar consolidation usually suggests bacterial coinfection. Community-acquired viral pathogens can cause more severe pneumonia in immunocompromised hosts, who are also susceptible to CMV and varicella infection. These latter 2 pathogens are less likely to manifest the striking airway-centric pattern. Airway-centric pattern is distinctly uncommon in Hantavirus pulmonary syndrome, a rare environmentally acquired infection with high mortality.

Mitral Annular Disjunction: Review of an Increasingly Recognized Mitral Valve Entity.

Mitral annular disjunction (MAD) refers to atrial displacement of the hinge point of the mitral valve annulus from the ventricular myocardium. MAD leads to paradoxical expansion of the annulus in systole and may often be associated with mitral valve prolapse (MVP), leaflet degeneration, myocardial and papillary muscle fibrosis, and, potentially, malignant cardiac arrhythmias. Patients with MAD and MVP may present similarly, and MAD is potentially the missing link in explaining why some patients with MVP experience adverse outcomes. Patients with a 5 mm or longer MAD distance have an elevated risk of malignant cardiac arrhythmia compared with those with a shorter MAD distance. Evaluation for MAD is an important component of cardiac imaging, especially in patients with MVP and unexplained cardiac arrhythmias. Cardiac MRI is an important diagnostic tool that aids in recognizing and quantifying MAD, MVP, and fibrosis in the papillary muscle and myocardium, which may predict and help improve outcomes following electrophysiology procedures and mitral valve surgery. This article reviews the history, pathophysiology, controversy, prevalence, clinical implications, and imaging considerations of MAD, focusing on cardiac MRI. Keywords: MR-Dynamic Contrast Enhanced, Cardiac, Mitral Valve, Mitral Annular Disjunction, Mitral Valve Prolapse, Floppy Mitral Valve, Cardiac MRI, Arrhythmia, Sudden Cardiac Death, Barlow Valve © RSNA, 2023.

Viral Pneumonias.

Viral pneumonia is usually community acquired and caused by influenza, parainfluenza, respiratory syncytial virus, human metapneumovirus, and adenovirus. Many of these infections are airway centric and chest imaging demonstrates bronchiolitis and bronchopneumonia, With the exception of adenovirus infections, the presence of lobar consolidation usually suggests bacterial coinfection. Community-acquired viral pathogens can cause more severe pneumonia in immunocompromised hosts, who are also susceptible to CMV and varicella infection. These latter 2 pathogens are less likely to manifest the striking airway-centric pattern. Airway-centric pattern is distinctly uncommon in Hantavirus pulmonary syndrome, a rare environmentally acquired infection with high mortality.

Comparison of Chest CT Findings of COVID-19, Influenza, and Organizing Pneumonia: A Multireader Study.

BACKGROUND. Previous studies compared CT findings of COVID-19 pneumonia with those of other infections; however, to our knowledge, no studies to date have included noninfectious organizing pneumonia (OP) for comparison. OBJECTIVE. The objectives of this study were to compare chest CT features of COVID-19, influenza, and OP using a multireader design and to assess the performance of radiologists in distinguishing between these conditions. METHODS. This retrospective study included 150 chest CT examinations in 150 patients (mean [± SD] age, 58 ± 16 years) with a diagnosis of COVID-19, influenza, or non-infectious OP (50 randomly selected abnormal CT examinations per diagnosis). Six thoracic radiologists independently assessed CT examinations for 14 individual CT findings and for Radiological Society of North America (RSNA) COVID-19 category and recorded a favored diagnosis. The CT characteristics of the three diagnoses were compared using random-effects models; the diagnostic performance of the readers was assessed. RESULTS. COVID-19 pneumonia was significantly different (p < .05) from influenza pneumonia for seven of 14 chest CT findings, although it was different (p < .05) from OP for four of 14 findings (central or diffuse distribution was seen in 10% and 7% of COVID-19 cases, respectively, vs 20% and 21% of OP cases, respectively; unilateral distribution was seen in 1% of COVID-19 cases vs 7% of OP cases; non-tree-in-bud nodules was seen in 32% of COVID-19 cases vs 53% of OP cases; tree-in-bud nodules were seen in 6% of COVID-19 cases vs 14% of OP cases). A total of 70% of cases of COVID-19, 33% of influenza cases, and 47% of OP cases had typical findings according to RSNA COVID-19 category assessment (p < .001). The mean percentage of correct favored diagnoses compared with actual diagnoses was 44% for COVID-19, 29% for influenza, and 39% for OP. The mean diagnostic accuracy of favored diagnoses was 70% for COVID-19 pneumonia and 68% for both influenza and OP. CONCLUSION. CT findings of COVID-19 substantially overlap with those of influenza and, to a greater extent, those of OP. The diagnostic accuracy of the radiologists was low in a study sample that contained equal proportions of these three types of pneumonia. CLINICAL IMPACT. Recognized challenges in diagnosing COVID-19 by CT are furthered by the strong overlap observed between the appearances of COVID-19 and OP on CT. This challenge may be particularly evident in clinical settings in which there are substantial proportions of patients with potential causes of OP such as ongoing cancer therapy or autoimmune conditions.

Case 287: Intrathoracic Migration of a Breast Implant after Video-assisted Thoracoscopic Surgery for Right Upper Lobectomy.

History A 60-year-old woman was diagnosed with a new right upper lobe stage I lung adenocarcinoma and underwent video-assisted thoracoscopic surgery (VATS) for right upper lobectomy. Her postoperative course was complicated by a large pneumothorax after chest tube removal on postoperative day 3. This was managed with repeat right-sided chest tube placement on the same day. The second chest tube was removed on postoperative day 8 without complications. A 2-week postoperative clinic visit was unremarkable. Postoperative chest radiographs on postoperative days 1, 3, and 8 are provided. Subsequently, chest CT scanning was performed as part of routine 6-month postsurgical lung cancer surveillance follow-up. The patient had no clinical complaints at routine follow-up. Physical examination revealed well-healed VATS scars in the chest wall. Laboratory results were within normal limits, including a normal white blood cell count of 6400/mL. Her surgical history included prior left upper lobectomy for remote left upper lobe stage IIIA adenocarcinoma and prior bilateral breast implantation for cosmesis. On the basis of chest CT findings, the patient was transferred from an outside institution.

Case 287.

History A 60-year-old woman was diagnosed with a new right upper lobe stage I lung adenocarcinoma and underwent video-assisted thoracoscopic surgery (VATS) for right upper lobectomy. Her postoperative course was complicated by a large pneumothorax after chest tube removal on postoperative day 3. This was managed with repeat right-sided chest tube placement on the same day. The second chest tube was removed on postoperative day 8 without complications. A 2-week postoperative clinic visit was unremarkable. Postoperative chest radiographs on postoperative days 1, 3, and 8 (Fig 1a-1c) are provided. Subsequently, chest CT scanning was performed as part of routine 6-month postsurgical lung cancer surveillance follow-up (Figs 2, 3). The patient had no clinical complaints at routine follow-up. Physical examination revealed well-healed VATS scars in the chest wall. Laboratory results were within normal limits, including a normal white blood cell count of 6400/µL. Her surgical history included prior left upper lobectomy for remote left upper lobe stage IIIA adenocarcinoma and prior bilateral breast implantation for cosmesis. On the basis of chest CT findings, the patient was transferred from an outside institution.

Analysis of Out-of-Pocket Cost of Lung Cancer Screening for Uninsured Patients Among ACR-Accredited Imaging Centers.

PURPOSE: To determine the variability in out-of-pocket costs of lung cancer screening (LCS) for uninsured patients and assess accessibility of this information by telephone or Internet. METHODS: LCS centers from the ACR's LCS database were randomly selected. Centers were called between July and August 2019 to determine out-of-pocket cost. Telephone call variables, accessibility of cost information on screening centers' websites, screening centers' chargemasters, and publicly available facility and state insurance coverage variables were obtained. Cost information was summarized using descriptive analyses. Multiple variable linear regression analyses were conducted to evaluate effects of facility and state-level characteristics on out-of-pocket costs. RESULTS: Fifty-five ACR-accredited LCS centers were included with 78% (43 of 55) willing to provide out-of-pocket cost. Average out-of-pocket cost was $583 ± $607 (mean ± standard deviation), range $49 to $2,409. Average telephone call length 6 ± 3.8 min. Two of fifty-five screening centers' websites provided out-of-pocket cost information, and one matched cost given over the telephone. A chargemaster was found for 30 of 55 screening centers. No statistically significant differences in out-of-pocket costs were found by geographic region, state percentages of uninsured residents, state percentages of residents with public insurance, or facility safety net hospital affiliation. DISCUSSION: Out-of-pocket LCS costs for uninsured patients and availability of this information is highly variable. Radiology practices should be aware of this variability that may influence participation rates among uninsured patients.

Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer: A Primer for Radiologists.

The past 2 decades have seen a rapid growth in use of stereotactic body radiation therapy (SBRT) for the management of non-small cell lung cancer (NSCLC). Not only is SBRT the reference standard for treatment of early-stage node-negative NSCLC in medically inoperable patients, it is also currently challenging the role of surgery for early-stage operable disease. SBRT is also used to treat recurrent disease and has a role in the management of multiple synchronous lung cancers. Imaging changes after SBRT differ from the changes after conventional radiation therapy in many ways, the knowledge of which is pertinent for accurate image interpretation. Posttreatment response assessment and detection of recurrent disease are heavily reliant on radiologic assessment, and often the decision to treat recurrent disease is based on the imaging findings themselves. This article provides a comprehensive review of the concepts of SBRT and the current indications for its use in the treatment of early-stage NSCLC, as well as a discussion of the CT findings seen after SBRT compared with the changes after conventional radiation therapy. Radiologic findings that are suggestive of recurrent disease and the imaging pitfalls are also highlighted. Finally, the rare complications after SBRT are described. SBRT is a major component of the changing treatment paradigms for early- and late-stage NSCLC. The imaging findings after SBRT often determine the next steps in a patient's clinical management. Therefore, radiologists must be familiar with the uses of this therapy and its radiologic appearance to be able to effectively contribute to the care of patients with NSCLC. ©RSNA, 2018.