Chest MRI with CT in the assessment of interstitial lung disease progression in patients with systemic sclerosis.

OBJECTIVE: To describe the performance of CT and MRI in the assessment of the progression of interstitial lung disease (ILD) associated with SSc and demonstrate the correlations of MRI with pulmonary function test (PFT) and CT scores. METHODS: This prospective single-centre observational study included patients with SSc diagnoses, and magnetic resonance (MR) images were assessed visually using the Scleroderma Lung Study (SLS) I system. Differences in the median scores were assessed with Student's t-test and the Wilcoxon rank-sum test. Pearson's and Spearman's rank correlation coefficients were calculated to correlate imaging scores and PFT results. Using disease progression as the gold standard, we calculated the area under the curve (AUC) of the CT and MRI scores with Harrel's c-index. The best thresholds for the prediction of disease progression were determined by receiver operating characteristic curve analysis with maximum Youden's Index (P < 0.05). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the scores were calculated. RESULTS: The AUCs for MRI and CT scores were 0.86 (0.72-0.98; P = 0.04) and 0.83 (0.70-0.99; P = 0.05), respectively. CT and MRI scores correlated with Forced vital capacity (%FVC) (MRI: r = -0.54, P = 0.0045; CT: r = -0.44; P = 0.137) and diffusing capacity of the lung for carbon monoxide (MRI: r = -0.39, P = 0.007; CT r = -0.36, P = 0.006). The sensitivity, specificity, PPV and NPV were 85%, 87.5%, 88.34% and 86.11% (MRI score) and 84.21%, 82.35%, 84.14% and 82.4% (CT score), respectively. CONCLUSIONS: MRI scores from patients with SSc may be an alternative modality for the assessment of ILD progression in patients with SSc.

Narrowing the Differential Diagnosis of Cystic Lesions in Smokers with Expiratory CT Acquisition Using the Cyst-Airway Communication Hypothesis.

The aim of this study was to assess percentage respiratory changes (δ) in the size of pulmonary cysts of different smoking-related etiologies. Retrospectively, we measured the cystic lesions due to histopathological-confirmed honeycombing from interstitial pulmonary fibrosis, pulmonary Langerhans cell histiocytosis (PLCH), and paraseptal emphysema, using paired inspiratory and expiratory CT scans. In a sample of 72 patients and 216 lesions, the mean diameter of PLCH and honeycombing decreased during expiration (PLCH, δ = 60.9%; p = 0.001; honeycombing, δ = 47.5%; p = 0.014). Conversely, paraseptal emphysema did not show any changes (δ = 5.2%; p = 0.34). In summary, our results demonstrated that cysts in smokers with PLCH and honeycombing fibrosis get smaller during expiratory CT scans, whereas the size of cystic-like lesions due to paraseptal emphysema and bullae tend to remain constant during respiratory cycles. These results support the hypothesis of cyst-airway communication in some cystic diseases, which could assist in the differential diagnosis in smoking-related lung diseases.

Utilization of Quantitative Computed Tomography Assessment to Identify Bronchiolitis Obliterans Syndrome After Single Lung Transplantation.

OBJECTIVE: To evaluate quantitative chest computed tomography (CT) methods for the detection of air trapping (AT) and to assess its diagnostic performance for the diagnosis of bronchiolitis obliterans syndrome (BOS) in single lung transplant (SLT) patients. METHODS: Adult patients who had a SLT at a single transplant center and underwent CT scan after transplantation were retrospectively included. CT findings of air trapping were measured by three different methods: expiratory air-trapping index (ATIexp), mean lung density on expiratory acquisition (MLDexp) and expiratory to inspiratory ratio of mean lung density (E/I-ratio(MLD). Sensitivity, specificity and diagnostic accuracy of the three methods for the detection of BOS status evaluated by serial routine measures of pulmonary function tests (gold standard) were assessed. RESULTS: Forty-six SLT patients (52.2% females, mean age 58 ± 6 years) were included in the analysis, 12 (26%) patients with a diagnosis of BOS. Quantitative CT diagnosis of AT ranged from 26 to 35%. Sensitivity, specificity and accuracy of each method for the detection of BOS were 85.7%, 84.7% and 85.0% for ATIexp, 78.5%, 93.4% and 90.0% for MLD and 64.2%, 89.1% and 83.3% E/I-ratio(MLD), respectively. CONCLUSION: Quantitative measures of AT obtained from standard CT are feasible and show high specificity and accuracy for the detection of BOS in SLT patients.

Comparison of the computed tomography findings in COVID-19 and other viral pneumonia in immunocompetent adults: a systematic review and meta-analysis.

OBJECTIVES: To compare the chest computed tomography (CT) findings of coronavirus disease 2019 (COVID-19) to other non-COVID viral pneumonia. METHODS: MEDLINE, EMBASE, and Cochrane databases were searched through April 04, 2020, for published English language studies. Studies were eligible if they included immunocompetent patients with up to 14 days of viral pneumonia. Subjects had a respiratory tract sample test positive for COVID-19, adenovirus, influenza A, rhinovirus, parainfluenza, or respiratory syncytial virus. We only included observational studies and case series with more than ten patients. The pooled prevalence of each chest CT pattern or finding was calculated with 95% confidence intervals (95% CI). RESULTS: From 2263 studies identified, 33 were eligible for inclusion, with a total of 1911 patients (COVID-19, n = 934; non-COVID, n = 977). Frequent CT features for both COVID-19 and non-COVID viral pneumonia were a mixed pattern of ground-glass opacity (GGO) and consolidation (COVID-19, 0.37; 0.17-0.56; non-COVID, 0.46; 0.35-0.58) or predominantly GGO pattern (COVID-19, 0.42; 0.28-0.55; non-COVID 0.25; 0.17-0.32), bilateral distribution (COVID-19, 0.81; 0.77-0.85; non-COVID, 0.69; 0.54-0.84), and involvement of lower lobes (COVID-19, 0.88; 0.80-0.95; non-COVID, 0.61; 0.50-0.82). COVID-19 pneumonia presented a higher prevalence of peripheral distribution (COVID-19 0.77; 0.67-0.87; non-COVID 0.34; 0.18-0.49), and involvement of upper (COVID-19, 0.77; 0.65-0.88; non-COVID 0.18; 0.10-0.27) and middle lobes (COVID-19, 0.61; 0.47-0.76; non-COVID 0.24; 0.11-0.38). CONCLUSION: Except for a higher prevalence of peripheral distribution, involvement of upper and middle lobes, COVID-19, and non-COVID viral pneumonia had overlapping chest CT findings. KEY POINTS: • Most common CT findings of coronavirus disease 2019 (COVID-19) were a predominant pattern of ground-glass opacity (GGO), followed by a mixed pattern of GGO and consolidation, bilateral disease, peripheral distribution, and lower lobe involvement. • Most frequent CT findings of non-COVID viral pneumonia were a predominantly mixed pattern of GGO and consolidation, followed by a predominant pattern of GGO, bilateral disease, random or diffuse distribution, and lower lobe involvement. • COVID-19 pneumonia presented a higher prevalence of peripheral distribution, and involvement of upper and middle lobes compared with non-COVID viral pneumonia.

18F-FDG PET/CT and whole-body MRI diagnostic performance in M staging for non-small cell lung cancer: a systematic review and meta-analysis.

OBJECTIVES: To evaluate the diagnostic test accuracy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT), whole-body magnetic resonance imaging (WB-MRI), and whole-body diffusion-weighted imaging (WB-DWI) for the detection of metastases in patients with non-small cell lung cancer (NSCLC). METHODS: MEDLINE, Embase, and Cochrane Library databases were searched up to June 2019. Studies were selected if they reported data that could be used to construct contingency tables to compare 18F-FDG PET/CT, WB-MRI, and WB-DWI. Two authors independently extracted data on study characteristics and assessed methodological quality using the Quality Assessment of Diagnostic Accuracy Studies. Forest plots were generated for sensitivity and specificity of 18F-FDG PET/CT, WB-MRI, and whole-body diffusion-weighted imaging (WB-DWI). Summary receiver operating characteristic plots were created. RESULTS: The 4 studies meeting inclusion criteria had a total of 564 patients and 559 lesions, 233 of which were metastases. In studies of 18F-FDG PET/CT, the pooled estimates of sensitivity and specificity were 0.83 (95% confidence interval [CI], 0.54-0.95) and 0.93 (95% CI, 0.87-0.96), respectively. For WB-MRI, pooled sensitivity was 0.92 (95% CI, 0.18-1.00) and pooled specificity was 0.93 (95% CI, 0.85-0.95). Pooled sensitivity and specificity for WB-DWI were 0.78 (95% CI, 0.46-0.93) and 0.91 (95% CI, 0.79-0.96), respectively. There was no statistical difference between the diagnostic odds ratio of WB-MRI and WB-DWI compared with that of PET/CT (p = 0.186 for WB-DWI; p = 0.638 for WB-MRI). CONCLUSION: WB-MRI and DWI are radiation-free alternatives with comparable diagnostic performance to 18F-FDG PET/CT for M staging of NSCLC. KEY POINTS: • Whole-body MRI with or without diffusion-weighted imaging has a high accuracy for the diagnostic evaluation of metastases in patients with non-small cell lung cancer. • Whole-body MRI may be used as a non-invasive and radiation-free alternative to positron emission tomography with CT with similar diagnostic performance.

Patient size matters: Effect of tube current modulation on size-specific dose estimates (SSDE) and image quality in low-dose lung cancer screening CT.

PURPOSE: We compare the effect of tube current modulation (TCM) and fixed tube current (FTC) on size-specific dose estimates (SSDE) and image quality in lung cancer screening with low-dose CT (LDCT) for patients of all sizes. METHODS: Initially, 107 lung screening examinations were performed using FTC, which satisfied the Centers for Medicare & Medicaid Services' volumetric CT dose index (CTDIvol ) limit of 3.0 mGy for standard-sized patients. Following protocol modification, 287 examinations were performed using TCM. Patient size and examination parameters were collected and water-equivalent diameter (Dw ) and SSDE were determined for each patient. Regression models were used to correlate CTDIvol and SSDE with Dw . Objective and subjective image quality were measured in 20 patients who had consecutive annual screenings with both FTC and TCM. RESULTS: CTDIvol was 2.3 mGy for all FTC scans and increased exponentially with Dw (range = 0.96-4.50 mGy, R2  = 0.73) for TCM scans. As patient Dw increased, SSDE decreased for FTC examinations (R2  = 1) and increased for TCM examinations (R2  = 0.54). Image quality measurements were superior with FTC for smaller sized patients and with TCM for larger sized patients (R2  > 0.5, P < 0.005). Radiologist graded all images acceptable for diagnostic evaluation of lung cancer screening. CONCLUSION: Although FTC protocol offered a consistently low CTDIvol for all patients, it yielded unnecessarily high SSDE for small patients and increased image noise for large patients. Lung cancer screening with LDCT using TCM produces radiation doses that are appropriately reduced for small patients and increased for large patients with diagnostic image quality for all patients.

Fluorine 18-FDG PET/CT and Diffusion-weighted MRI for Malignant versus Benign Pulmonary Lesions: A Meta-Analysis.

Purpose To perform a meta-analysis of the literature to compare the diagnostic performance of fluorine 18 fluorodeoxyglucose PET/CT and diffusion-weighted (DW) MRI in the differentiation of malignant and benign pulmonary nodules and masses. Materials and Methods Published English-language studies on the diagnostic accuracy of PET/CT and/or DW MRI in the characterization of pulmonary lesions were searched in relevant databases through December 2017. The primary focus was on studies in which joint DW MRI and PET/CT were performed in the entire study population, to reduce interstudy heterogeneity. For DW MRI, lesion-to-spinal cord signal intensity ratio and apparent diffusion coefficient were evaluated; for PET/CT, maximum standard uptake value was evaluated. The pooled sensitivities, specificities, diagnostic odds ratios, and areas under the receiver operating characteristic curve (AUCs) for PET/CT and DW MRI were determined along with 95% confidence intervals (CIs). Results Thirty-seven studies met the inclusion criteria, with a total of 4224 participants and 4463 lesions (3090 malignant lesions [69.2%]). In the primary analysis of joint DW MRI and PET/CT studies (n = 6), DW MRI had a pooled sensitivity and specificity of 83% (95% CI: 75%, 89%) and 91% (95% CI: 80%, 96%), respectively, compared with 78% (95% CI: 70%, 84%) (P = .01 vs DW MRI) and 81% (95% CI: 72%, 88%) (P = .056 vs DW MRI) for PET/CT. DW MRI yielded an AUC of 0.93 (95% CI: 0.90, 0.95), versus 0.86 (95% CI: 0.83, 0.89) for PET/CT (P = .001). The diagnostic odds ratio of DW MRI (50 [95% CI: 19, 132]) was superior to that of PET/CT (15 [95% CI: 7, 32]) (P = .006). Conclusion The diagnostic performance of diffusion-weighted MRI is comparable or superior to that of fluorine 18 fluorodeoxyglucose PET/CT in the differentiation of malignant and benign pulmonary lesions. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Schiebler in this issue.

Gender disparity in academic emergency radiology.

OBJECTIVE: This study is intended to better understand how academic productivity and career advancement differs between men and women emergency radiologists in academic practices. MATERIALS AND METHODS: Parameters of academic achievement were measured, including number of citations, number of publications, and h-index, while also collecting information on academic and leadership ranking among emergency radiologists in North America. RESULTS: In emergency radiology, there are significantly fewer women than men (22.2% vs 77.8%). Of these women, the greatest proportion of women held the lower academic rank of assistant professor (95.4%). Female assistant professors had a higher h-index than men at the same rank (4 vs 2), but it was not statistically significantly higher. There was no significant difference between gender and academic (p = 0.089) or leadership (p = 0.586) rankings. CONCLUSION: This study provides further evidence that gender disparity persists in emergency radiology, with women achieving less upward academic career mobility than men, despite better academic productivity in the earlier stages of their careers. The academic productivity of emergency radiologists at the rank of assistant professor is significantly higher for women than men.

Core curriculum illustration: blunt trauma to the bowel.

This is the 22nd installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm .

JOURNAL CLUB: Assessment of Interobserver Variability in the Peer Review Process: Should We Agree to Disagree?

OBJECTIVE: Peer review is an important and necessary part of radiology. There are several options to perform the peer review process. This study examines the reproducibility of peer review by comparing two scoring systems. MATERIALS AND METHODS: American Board of Radiology-certified radiologists from various practice environments and subspecialties were recruited to score deidentified examinations on a web-based PACS with two scoring systems, RADPEER and Cleareview. Quantitative analysis of the scores was performed for interrater agreement. RESULTS: Interobserver variability was high for both the RADPEER and Cleareview scoring systems. The interobserver correlations (kappa values) were 0.17-0.23 for RADPEER and 0.10-0.16 for Cleareview. Interrater correlation was not statistically significantly different when comparing the RADPEER and Cleareview systems (p = 0.07-0.27). The kappa values were low for the Cleareview subscores when we evaluated for missed findings (0.26), satisfaction of search (0.17), and inadequate interpretation of findings (0.12). CONCLUSION: Our study confirms the previous report of low interobserver correlation when using the peer review process. There was low interobserver agreement seen when using both the RADPEER and the Cleareview scoring systems.

Geriatric Trauma: A Radiologist's Guide to Imaging Trauma Patients Aged 65 Years and Older.

Radiologists play an important role in evaluation of geriatric trauma patients. Geriatric patients have injury patterns that differ markedly from those seen in younger adults and are susceptible to serious injury from minor trauma. The spectrum of trauma in geriatric patients includes head and spine injury, chest and rib trauma, blunt abdominal injury, pelvic fractures, and extremity fractures. Clinical evaluation of geriatric trauma patients is difficult because of overall frailty, comorbid illness, and medication effects. Specific attention should be focused on the effects of medications in this population, including anticoagulants, steroids, and bisphosphonates. Radiologists should use age-appropriate algorithms for radiography, computed tomography (CT), and magnetic resonance imaging of geriatric trauma patients and follow guidelines for intravenous contrast agent administration in elderly patients with impaired renal function. Because there is less concern about risk for cancer with use of ionizing radiation in this age group, CT is the primary imaging modality used in the setting of geriatric trauma. Clinical examples are provided from the authors' experience at a trauma center where geriatric patients who have sustained major and minor injuries are treated daily.

Core curriculum illustration: scapulothoracic disassociation.

This is the 14th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at:  http://www.aseronline.org/curriculum/toc.htm .

Core curriculum illustration: pediatric traumatic spondylolisthesis of the axis.

This is the 16th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm.

Core curriculum illustration: blunt cerebrovascular injury.

This is the 15th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm .

Evaluating Acute Pulmonary Changes of Coronavirus 2019: Comparative Analysis of the Pertinent Modalities.

This review explores imaging's crucial role in acute Coronavirus Disease 2019 (COVID-19) assessment. High Resolution Computer Tomography is especially effective in detection of lung abnormalities. Chest radiography has limited utility in the initial stages of COVID-19 infection. Lung Ultrasound has emerged as a valuable, radiation-free tool in critical care, and Magnetic Resonance Imaging shows promise as a Computed Tomography alternative. Typical and atypical findings of COVID-19 by each of these modalities are discussed with emphasis on their prognostic value. Considerations for pediatric and immunocompromised cases are outlined. A comprehensive diagnostic approach is recommended, as radiological diagnosis remains challenging in the acute phase.

Chronic Chest Computed Tomography Findings Following COVID-19 Pneumonia.

Respiratory symptoms are a frequent manifestation of patients with post-acute sequela of SARS-CoV-2 (PASC), also known as long-COVID. Many cohorts of predominantly hospitalized patients have shown that a significant subset may have persistent chest computed tomography findings for more than 12 months after the acute infection. Proper understanding of the evolving long-term imaging findings and terminology is crucial for accurate imaging interpretation and patient care. The goal of this article is to review the chronic chest computed tomography findings of patients with PASC and common pitfalls.

Developing a Late-Career Roadmap to Continued Career Engagement.

Professional development needs span the entirety of a radiologist's career. Great strides have been made in the creation of an infrastructure for early career development. Work is ongoing to develop such resources for mid-career radiologists, given the recent recognition of the needs of this group. Unfortunately, even less attention has been paid to late-career radiologist development needs as a bridge to retirement. As part of the Career Conversations series, this article will highlight the needs and currently available resources for this group.

Pictorial Summary of Congenital Gallbladder and Biliary Duct Anomalies Presentation on HIDA Imaging.

Hepatobiliary iminodiacetic acid (HIDA) scan is one of the principal imaging modalities for the evaluation of the gallbladder and biliary tree. Congenital biliary anomalies are rare and can be difficult to recognize on HIDA scan. They may also mimic other biliary pathology. The purpose of this article is to review the spectrum of congenital gallbladder and biliary anomalies and describe their imaging appearance on HIDA scan. In addition, the diagnostic utility of functional imaging with HIDA when evaluating biliary tract anomalies is described.

Expiratory CT scanning in COVID-19 patients: can we add useful data?

OBJECTIVE: To evaluate small airway disease in COVID-19 patients using the prevalence of air trapping (AT) and correlating it with clinical outcomes. The relationship between CT-based opacities in small blood vessels and ventilation in patients with SARS-CoV-2 pneumonia was also assessed. METHODS: We retrospectively included 53 patients with positive RT-PCR results for SARS-CoV-2 between March and April of 2020. All subjects underwent HRCT scanning, including inspiratory and expiratory acquisitions. Subjects were divided into two groups based on visual identification of AT. Small blood vessel volumes were estimated by means of cross-sectional areas < 5 mm2 (BV5) derived from automated segmentation algorithms. Mixed-effect models were obtained to represent the BV5 as a function of CT-based lobar opacities and lobar ventilation. RESULTS: Of the 53 participants, AT was identified in 23 (43.4%). The presence of AT was associated with increased SpO2 at admission (OR = 1.25; 95% CI, 1.07-1.45; p = 0.004) and reduced D-dimer levels (OR = 0.99; 95% CI, 0.99-0.99; p = 0.039). Patients with AT were less likely to be hospitalized (OR = 0.27; 95% CI, 0.08-0.89; p = 0.032). There was a significant but weak inverse correlation between BV5 and CT-based lobar opacities (R2 = 0.19; p = 0.03), as well as a nonsignificant and weak direct correlation between BV5 and lobar ventilation (R2 = 0.08; p = 0.54). CONCLUSIONS: AT is a common finding in patients with COVID-19 that undergo expiratory CT scanning. The presence of AT may correlate with higher SpO2 at admission, lower D-dimer levels, and fewer hospitalizations when compared with absence of AT. Also, the volume of small pulmonary vessels may negatively correlate with CT opacities but not with lobar ventilation.