Persistent or slow-growing subsolid nodules and atypical lung cysts often represent indolent forms of lung cancer. These nodules require careful assessment by a multidisciplinary tumor board to determine risk, natural history, treatment options, and patient preferences. When the preferred management is imaging surveillance rather than active intervention, the main objective is to detect significant changes that could alter patient management. The choice of imaging modality should be based on its accuracy and whether the findings will influence the decision to pursue treatment. If the team determines that treatment is necessary, a diagnostic imaging workup and a biopsy are typically indicated and should not be considered part of surveillance. Therefore, this document aims to outline evidence-based guidelines specifically for imaging surveillance of indolent pulmonary nodules in patients for whom the clinical team has chosen to delay intervention. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Preprocedural chest or cardiac imaging for cardiothoracic surgery is focused on the imaging necessary to inform the performance of a surgical procedure after an initial diagnosis and the decision to operate has been made with consideration of patient comorbidities and anesthesia risk. The diverse range of noncoronary cardiac surgeries, coronary cardiac surgeries, and thoracic surgeries each have their own unique surgical techniques, risks, and complications, which can further vary between patients undergoing first time or repeat cardiothoracic surgery. This document reviews the literature for preprocedural chest or cardiac imaging in patients with and without a history of cardiothoracic surgery. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Diffuse lung diseases (DLD) also referred to as diffuse parenchymal lung diseases or interstitial lung diseases encompass diverse disorders affecting the lung parenchyma with possible multicompartment involvement in the chest. DLD include several hundred established clinical syndromes and pathologies, with a variety of possible etiologies. Imaging plays a central role during multidisciplinary discussion, which constitutes the current standard for diagnosis and monitoring of DLD. This document aims to establish guidelines for evaluation of diffuse lung diseases for 1) initial imaging of suspected diffuse lung disease, 2) initial imaging of suspected acute exacerbation or acute deterioration in cases of confirmed diffuse lung disease, and 3) surveillance of confirmed diffuse lung disease without acute deterioration. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Acute respiratory illness is one of the leading causes of morbidity and mortality amongst infectious diseases worldwide and a major public health issue. Even though most cases are due to self-limited viral infections, a significant number of cases are due to more serious respiratory infections where delay in diagnosis can lead to morbidity and mortality. Imaging plays a key role in the initial diagnosis and management of acute respiratory illness. This document reviews the current literature concerning the appropriate role of imaging in the diagnosis and management of the immunocompetent adult patient initially presenting with acute respiratory illness. Imaging recommendations for adults presenting with asthma or chronic obstructive pulmonary disease exacerbations are discussed. Finally, guidelines for follow-up imaging in suspected pneumonia cases to ensure occult malignancy is not overlooked. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or intermediate, experts may be the primary evidentiary source available to formulate a recommendation.

For patients with chronic dyspnea of noncardiovascular origin, chest radiography is usually appropriate as the first-line imaging modality. Chest CT without contrast is either usually appropriate or may be appropriate as a second-line option for conditions of unclear etiology or suspected chronic obstructive pulmonary disease, small airways disease, and post-COVID-19 complications. Chest CT with contrast may have a role in patients with pleura/chest wall disease or diaphragm dysfunction. Although MRI, fluoroscopy, and FDG-PET/CT have limited roles, special imaging techniques such as inspiratory/expiratory CT and hyperpolarized xenon gas MRI are noted for their specific uses. This document aims to help clinicians choose the most suitable imaging tests, enhancing diagnostic accuracy and patient care. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

This document reviews the evidence supporting different imaging modalities and techniques used to evaluate patients with a history of lung cancer. It focuses on the imaging evaluation of patients treated for stage I-III non-small-cell lung cancer and small-cell lung cancer, whether using individual modalities or combinations. Guidelines for both routine surveillance of stage I-III lung cancer and for the evaluation of suspected recurrence or disease progression are provided. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Despite overwhelming data detailing the harm of cigarette use, nearly 1.25 billion people worldwide continue to smoke. Amongst the myriad afflictions associated with cigarette use, smoking related interstitial lung disease is a common and likely underrecognized entity given the overlap and lack of consensus in clinical, pathological, and radiological diagnosis.Many characteristic patterns of disease have been identified on diagnostic chest imaging, and using a pattern-based approach to radiologic diagnosis can improve diagnostic accuracy. Several discrete disease processes are categorized as smoking related interstitial lung disease and range from a potentially reversible desquamative interstitial pneumonia/alveolar macrophage pneumonia, to chronic and insidious onset idiopathic pulmonary fibrosis with high morbidity and mortality.This article reviews the common clinical findings and demographics associated with patient presentation, histopathological findings for each of the smoking related interstitial lung diseases upon tissue sampling or biopsy and suggests a pattern-based approach to radiologic diagnosis.

PURPOSE:To evaluate the academic impact of the American College of Radiology thoracic and cardiac Appropriateness Criteria (ACR-AC) guideline publications through citation analysis. METHODS:The Scopus database was used to collect publication year, version number, and number and identity of citing publications for thoracic and cardiac imaging ACR-AC guideline publications. For each citing article, the journal name and impact factor, publication year, countries of all authors, and language(s) of publication were collected. An article h-index was computed for each ACR-AC guideline. RESULTS:31 thoracic and cardiac ACR-AC guideline publications received 758 citations from 379 journals, with authors representing 62 countries. The median citation count was 15 (range = 1-97) and the median article h-index was 5 (range = 1-19). The most frequent country of authorship of articles citing an ACR-AC guideline publication was the United States, but 66.7 % of authors were from other countries. The median impact factor for the citing journals was 3.0 (range = 0.0-521.6). A majority of the total citations were from "Non-Radiology Journals" (n = 422/758 [55.7 %]) which comprised a majority of all journals represented (n = 295/379 [77.8 %]). CONCLUSIONS:Citation characteristics of ACR-AC guideline publications suggest broad multidisciplinary and global academic influence.

In the context of known cancer, imaging is crucial for staging, including assessing lymph node tastases. Understanding common pathways lymphatic spread allows the radiologist to focus their search pattern, potentially identifying early nodal metastatic disease that might otherwise overlooked. Conversely, detecting abnormal lymph nodes can guide the search for the most likely origin site of the neoplasm (Table 2).

Substance abuse continues to be prevalent nationwide and can lead to a myriad of chest pathologies. Imaging findings are vast and can include nodules, masses, ground-glass opacities, airspace disease, and cysts. Radiologists with awareness of these manifestations can assist in early identification of disease in situations where information is unable to be obtained from the patient. This review focuses on thoracic imaging findings associated with various forms of substance abuse, which are organized by portal of entry into the thorax: inhalation, ingestion, and injection.

PURPOSE:The objective of this study is to identify and detail the radiologic manifestations of surgical site and disseminated Mycobacterium chimaera (MC) infection. The aim is to facilitate early identification and diagnosis of MC, considering its indolent nature and the challenges involved in clinically and pathologically establishing the diagnosis.PATIENTS AND METHODS:This was a retrospective cohort study reviewing computed tomography (CT), positron emission tomography (PET)/CT, and magnetic resonance imaging examinations in patients over the age of 18 years with a history of open heart surgery and a clinical or pathologic diagnosis of MC. Two radiology residents, a fellowship-trained nuclear medicine radiologist, and a fellowship-trained cardiothoracic radiologist performed consensus reads to determine the imaging findings seen in MC infection.RESULTS:Twenty-five patients were included. Localized, surgical site infection was more common than disseminated disease. Typical CT findings included peristernal soft tissue thickening, sinus tracts often extending to the cutaneous surface, slowly enlarging fluid collections, and sternal osteolysis. PET/CT findings demonstrated hypermetabolic activity in nearly all patients localized to sites of infection. Imaging findings for disseminated infection included hepatosplenomegaly, lymphadenopathy, involvement of the central nervous system, discitis/osteomyelitis, and distant abscesses.CONCLUSIONS:Imaging plays a vital role in suggesting possible surgical sites and disseminated MC infection acquired from open heart surgery. Radiologists must keep a high index of suspicion given the indolent nature and subtle imaging change over time. PET/CT is most useful in diagnosis and helps in differentiating between a sterile postoperative fluid collection or scarring and active MC infection and helps provide a target for debridement.

Progressive pulmonary fibrosis (PPF) and interstitial lung abnormalities (ILA) are relatively new concepts in interstitial lung disease (ILD) imaging and clinical management. Recognition of signs of PPF and identification and classification of ILA are important tasks during chest high-resolution CT interpretation to optimize management of patients with ILD and those at risk of developing ILD. However, in professional society guidance, the role of imaging surveillance remains unclear for stable patients with ILD, asymptomatic patients with ILA who are at risk of progression, and asymptomatic patients at risk of developing ILD without imaging abnormalities. In this AJR Expert Panel Narrative Review, we summarize the current knowledge regarding PPF and ILA and describe the range of clinical practice with respect to imaging patients with ILD, those with ILA, and those at risk of developing ILD. In addition, we offer suggestions to help guide surveillance imaging in areas with an absence of published guidelines, where such decisions are currently driven primarily by local pulmonologists' preference.

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. A search for the underlying cause of infection typically includes radiological imaging as part of this investigation. This document focuses on thoracic and abdominopelvic causes of sepsis. In 2017, the global incidence of sepsis was estimated to be 48.9 million cases, with 11 million sepsis-related deaths (accounting for nearly 20% of all global deaths); therefore, understanding which imaging modalities and types of studies are acceptable or not acceptable is imperative. The 5 variants provided include the most commonly encountered scenarios in the setting of sepsis along with recommendations and data for each imaging study.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Purpose: Closed-loop imaging programs (CLIPs) are designed to ensure that patients receive appropriate follow-up, but a review of incidental CT-detected breast findings in the setting of CLIPs has not been performed. Methods: A retrospective review was conducted of CT reports at a single academic institution from July 1, 2020, to January 31, 2022, to identify reports with recommendations for breast imaging follow-up. Medical records were reviewed to evaluate patient adherence to follow-up, CLIP intervention, subsequent BI-RADS assessment, and diagnosis. Adherence was defined as diagnostic breast imaging performed within 6 months of the CT recommendation. Results: Follow-up recommendations for breast imaging were included in CT report impressions for 311 patients. Almost half of patients (47.3% [147 of 311]) underwent follow-up breast imaging within 6 months, yielding breast cancer diagnoses in 12.9% (19 of 147) and a biopsy-proven positive predictive value of 65.5% (19 of 29). Most patients who returned for follow-up within 6 months did so without CLIP intervention. The majority of CT report impressions in the follow-up group (85.0% [125 of 147]) contained specific recommendations for "diagnostic breast imaging." For patients who did not receive follow-up, the CLIP team tracked all cases and intervened in 19.1% (28 of 147). The most common intervention was a phone call and/or fax to the primary care provider. Outpatient CT examination setting and specific recommendation for diagnostic breast imaging were significantly associated with higher follow-up adherence (P < .0001). Conclusions: Actionable CT-detected breast findings require follow-up diagnostic breast imaging because of a relevant cancer detection rate of 12.9%. Although many patients return for breast imaging without intervention, almost half of patients did not receive follow-up and may account for a significant number of missed cancer diagnoses. Specific CT recommendation verbiage is associated with higher follow-up adherence, which can be addressed across settings even without CLIPs.

A variety of thoracic imaging modalities and techniques have been used to evaluate diseases of the trachea and central bronchi. This document evaluates evidence for the use of thoracic imaging in the evaluation of tracheobronchial disease, including clinically suspected tracheal or bronchial stenosis, tracheomalacia or bronchomalacia, and bronchiectasis. Appropriateness guidelines for initial imaging evaluation of tracheobronchial disease and for pretreatment planning or posttreatment evaluation are included. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.