RadioGraphics Update: Lung-RADS 2022.

Editor's Note.-RadioGraphics Update articles supplement or update information found in full-length articles previously published in RadioGraphics. These updates, written by at least one author of the previous article, provide a brief synopsis that emphasizes important new information such as technological advances, revised imaging protocols, new clinical guidelines involving imaging, or updated classification schemes.

Lung-RADS: Pushing the Limits.

In response to the recommendation of the U.S. Preventive Services Task Force and the coverage decision by the Centers for Medicare and Medicaid Services for lung cancer screening (LCS) computed tomography (CT), the American College of Radiology introduced the Lung CT Screening Reporting and Data System (Lung-RADS) in 2014 to standardize the reporting and management of screening-detected lung nodules. As with many first-edition guidelines, questions arise when such reporting systems are used in daily practice. In this article, a collection of 15 LCS-related scenarios are presented that address situations in which the Lung-RADS guidelines are unclear or situations that are not currently addressed in the Lung-RADS guidelines. For these 15 scenarios, the authors of this article provide the reader with recommendations that are based on their collective experiences, with the hope that future versions of Lung-RADS will provide additional guidance, particularly as more data from widespread LCS are collected and analyzed. ©RSNA, 2017.

Association between mucoid Pseudomonas infection and bronchiectasis in children with cystic fibrosis.

PURPOSE: To correlate the severity of bronchiectasis in children with cystic fibrosis with clinical and microbiologic variables in order to clarify risk factors for the development of irreversible lung disease. MATERIALS AND METHODS: After institutional review board approval and parental informed consents were obtained, a HIPAA-compliant longitudinal epidemiologic evaluation was performed in patients with cystic fibrosis who were enrolled in the Wisconsin trial of newborn screening from 1985 to 2009. Thin-section chest computed tomography (CT) was used in a prospective cross-sectional design to study patients ranging in age from 6.6 to 17.6 years (mean, 11.5 years). Thin-section CT scores were determined objectively on coded images by multiple raters in a standardized fashion. Microbiologic data were obtained by means of culture of respiratory secretions by using methods for differentiation of Pseudomonas aeruginosa (PA) as either nonmucoid or mucoid. RESULTS: Eighty-three percent of patients (68 of 82) showed bronchiectasis of varying severity. Of 12 potential risk factors, only respiratory infection with mucoid PA correlated significantly with bronchiectasis (P = .041). CONCLUSION: The severity of bronchiectasis in children with cystic fibrosis is significantly related to respiratory infection with mucoid PA; attempts to prevent bronchiectasis should include reducing exposure to and early eradication of PA.

Microwave ablation with triaxial antennas tuned for lung: results in an in vivo porcine model.

PURPOSE: To prospectively determine in swine the size and shape of coagulation zones created in normal lung tissue by using small-diameter triaxial microwave antennas and to prospectively quantify the effects of bronchial occlusion and multiple antennas on the coagulation zone. MATERIALS AND METHODS: The study was approved by the research animal care and use committee, and all husbandry and experimental studies were compliant with the National Research Council's Guide for the Care and Use of Laboratory Animals. Twenty-four coagulation zones (three per animal) were created at thoracotomy in eight female domestic swine (mean weight, 55 kg) by using a microwave ablation system with 17-gauge lung-tuned triaxial antennas. Ablations were performed for 10 minutes each by using (a) a single antenna, (b) a single antenna with bronchial occlusion, and (c) an array of three antennas powered simultaneously. The animals were sacrificed immediately after ablation. The coagulation zones were excised en bloc and sectioned into approximately 4-mm slices for measurement of size, shape, and circularity. Analysis of variance and two-sample t tests were used to identify differences between the three ablation groups. RESULTS: The overall mean diameters of coagulation achieved with a single antenna and bronchial occlusion (4.11 cm +/- 1.09 [standard deviation]) and with multiple-antenna arrays (4.05 cm +/- 0.69) were significantly greater than the overall mean diameter achieved with a single antenna alone (3.09 cm +/- 0.83) (P = .016 for comparison with multiple antennas, P = .032 for comparison with bronchial occlusion). No significant differences in size were seen between the coagulation zones created with bronchial occlusion and those created with multiple antennas (P = .68). The coagulation zones in all groups were very circular (isoperimetric ratio > 0.80) at cross-sectional analysis. CONCLUSION: A 17-gauge triaxial microwave ablation system tuned for lung tissue yielded large circular zones of coagulation in vivo in porcine lungs. The coagulation zones created with bronchial occlusion and multiple antennas were significantly larger than those created with one antenna.

Multidetector computed tomography detection of bronchial diverticula.

Bronchial diverticula are associated with chronic obstructive pulmonary disease. With newer scanners, small structures such as these air-filled diverticula will be visible and could be mistaken for pneumomediastinum. We present a case in which retrospectively reconstructed thin-section computed tomography clearly depicted the presence of multiple bronchial diverticula enabling the diagnosis to be made with certainty.

Dual-energy subtraction chest radiography: what to look for beyond calcified nodules.

Dual-energy subtraction chest radiography is a robust and powerful tool that improves the ability to detect and accurately diagnose a wide variety of thoracic abnormalities on posteroanterior-lateral chest images. Dual-energy subtraction chest radiography has many advantages over conventional chest radiography that facilitate image interpretation. The major advantage of this imaging technique is that it more clearly depicts calcification, which greatly aids in characterizing pulmonary nodules. Dual-energy subtraction images are also helpful in the recognition of hilar and mediastinal masses; the detection of tracheal narrowing and vascular disease; the identification of bone, pleural, and chest wall abnormalities; and the localization of indwelling devices such as stents and catheters. However, dual-energy subtraction imaging also has some limitations of which the radiologist should be aware and requires a somewhat higher radiation dose than does conventional radiography.

Reproducibility of a scoring system for computed tomography scanning in cystic fibrosis.

INTRODUCTION: Computerized tomography (CT) scanning shows promise as an outcome surrogate for cystic fibrosis (CF) lung disease progression. The scoring system used to convert the CT image to numeric data is an essential determinant of the performance of CT scanning. METHODS: Three radiologists independently scored 16 high-resolution CT scans performed on children in the Wisconsin CF Neonatal Screening Project. The test scans were selected to provide a broad range of disease severity. The scoring system provided subscores for the presence and severity of 5 findings of CF lung disease. The sum of the subscores provided a total score. The CT scans were then read again by each of the radiologists at least 11 months later. Using Mixed Effects Linear Model Analysis, the sources of error (scan-to-scan variation, interrater variance, and intrarater variance) were calculated. RESULTS: For the total score, the scan-to-scan variation was 14.48, interrater variance was 0.28, and intrarater variance was 0.45, with an overall reproducibility of 95%. The square root of scan-to-scan variance, a measure of sensitivity, was 3.81. Evaluation of the subscores showed higher reproducibility for bronchiectasis and hyperinflation (95% and 88%, respectively). The bronchiectasis score was more sensitive than the air-trapping score (1.46 vs. 0.89). DISCUSSION: This system was developed to provide a reproducible method that could be used to evaluate the lobar location, severity, and extent of a broad spectrum of CT features of CF lung disease, especially in children. This study demonstrates that the overall score is both sensitive to variation in the severity of lung disease and reproducible.

Anatomic pitfalls of the heart and pericardium.

Recent technologic advances have led to more frequent dedicated cross-sectional imaging of the heart. Faster scanning techniques, cardiac gating, and advanced postprocessing software allow improved visualization of finer anatomic details of the heart and pericardium compared with older techniques and software. Use of thin-section computed tomography (CT) or image reformatting in nonaxial planes may be helpful in some cases. The cardiac and pericardial structures are usually readily demonstrated with CT, even if chest CT is performed for evaluation of noncardiac structures. However, radiologists are expected to evaluate all structures on an image, and incidental findings are common. Radiologists must first be familiar with the normal anatomic structures of the heart and pericardium (eg, atria, ventricles, cardiac valves, pericardial recesses, paracardiac structures) to avoid mistaking them for pathologic processes.

Optimizing electronic presentations.

RATIONALE AND OBJECTIVES: Radiologists often use electronic presentations for educational and research purposes. Many physician educators may not know how to best utilize this technology. MATERIALS AND METHODS: A literature search was performed to find information regarding optimal use of electronic presentations. RESULTS AND CONCLUSION: Information from a variety of sources was compiled to provide a guideline for creating electronic presentations.

PET scan-CT correlation: what the chest radiologist needs to know.

The purpose of this article is to familiarize the chest radiologist with the basics of PET scanning in the chest and to correlate PET findings with thoracic CT findings. After completing this article, the reader should know the following: (a) how PET scanning is performed; (b) the indications for PET scanning in the chest; (c) the significance of SUV and a positive test; (c) the causes of false-positive and false-negative PET scans; and (d) the importance of correlating PET findings with Chest CT findings. The authors conclude that PET and chest CT studies should be read in conjunction to optimize diagnostic accuracy. Interpreting either study alone is fraught with errors, while combined interpretations yield information on both functional activity and anatomic localization. PET-CT hybrid devices that fuse PET and CT data simplify this task and fusion imaging is rapidly becoming the test of choice for evaluating thoracic malignancies.

Image-guided coaxial fine needle aspiration biopsy with a side-exiting guide.

PURPOSE: The aim of this study was to evaluate the diagnostic accuracy and complication rates of a side-exiting coaxial needle system for fine needle aspiration (FNA) biopsies. METHOD: Between 1995 and 1998, 127 nonconsecutive biopsies were performed on 122 patients (74 males, 48 females). CT guidance was used in 111, ultrasound guidance was used in 14, and both were used in 2 biopsies. Patient history, biopsy site, needle performance, complications, and cytology results were recorded. RESULTS: Diagnostic rate and accuracy were 92.9 and 99.2%, respectively. There were minor complications from 14 biopsies, and all of them arose from chest biopsies: pneumothorax in 13 of 47 and hemoptysis in 1 of 47. There were no major complications. CONCLUSION: The side-exiting coaxial needle system is a safe and effective alternative to the conventional end-exiting coaxial needle system for performance of image-guided FNA biopsies.

Automated storage and retrieval of thin-section CT images to assist diagnosis: system description and preliminary assessment.

A software system and database for computer-aided diagnosis with thin-section computed tomographic (CT) images of the chest was designed and implemented. When presented with an unknown query image, the system uses pattern recognition to retrieve visually similar images with known diagnoses from the database. A preliminary validation trial was conducted with 11 volunteers who were asked to select the best diagnosis for a series of test images, with and without software assistance. The percentage of correct answers increased from 29% to 62% with computer assistance. This finding suggests that this system may be useful for computer-assisted diagnosis.