Managing Incidental Findings on Thoracic CT: Lung Findings. A White Paper of the ACR Incidental Findings Committee.

The ACR Incidental Findings Committee presents recommendations for managing incidentally detected lung findings on thoracic CT. The Chest Subcommittee is composed of thoracic radiologists who endorsed and developed the provided guidance. These recommendations represent a combination of current published evidence and expert opinion and were finalized by informal iterative consensus. The recommendations address commonly encountered incidental findings in the lungs and are not intended to be a comprehensive review of all pulmonary incidental findings. The goal is to improve the quality of care by providing guidance on management of incidentally detected thoracic findings.

Use of a Dual Artificial Intelligence Platform to Detect Unreported Lung Nodules.

OBJECTIVE: To investigate the performance of Dual-AI Deep Learning Platform in detecting unreported pulmonary nodules that are 6 mm or greater, comprising computer-vision (CV) algorithm to detect pulmonary nodules, with positive results filtered by natural language processing (NLP) analysis of the dictated report. METHODS: Retrospective analysis of 5047 chest CT scans and corresponding reports. Cases which were both CV algorithm positive (nodule ≥ 6 mm) and NLP negative (nodule not reported), were outputted for review by 2 chest radiologists. RESULTS: The CV algorithm detected nodules that are 6 mm or greater in 1830 (36.3%) of 5047 cases. Three hundred fifty-five (19.4%) were unreported by the radiologist, as per NLP algorithm. Expert review determined that 139 (39.2%) of 355 cases were true positives (2.8% of all cases). One hundred thirty (36.7%) of 355 cases were unnecessary alerts-vague language in the report confounded the NLP algorithm. Eighty-six (24.2%) of 355 cases were false positives. CONCLUSIONS: Dual-AI platform detected actionable unreported nodules in 2.8% of chest CT scans, yet minimized intrusion to radiologist's workflow by avoiding alerts for most already-reported nodules.

Management of Incidental Adnexal Findings on CT and MRI: A White Paper of the ACR Incidental Findings Committee.

The ACR Incidental Findings Committee (IFC) presents recommendations for managing adnexal masses incidentally detected on CT and MRI. These recommendations represent an update of those provided in our previous JACR 2013 white paper. The Adnexal Subcommittee, which included six radiologists with subspecialty expertise in abdominal imaging or ultrasound and one gynecologist, developed this algorithm. The recommendations draw from published evidence and expert opinion and were finalized by iterative consensus. Algorithm branches successively categorize adnexal masses based on patient characteristics (eg, pre- versus postmenopausal) and imaging features. They terminate with a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. Our goal is to improve quality of care by providing guidance on how to manage incidentally detected adnexal masses.

Relationships Between Health Care Disparities and Coverage Policies for Breast, Colon, and Lung Cancer Screening.

Disparities in outcomes exist for breast, colon, and lung cancer among diverse populations, particularly racial and ethnic underrepresented minorities (URMs) and individuals from lower socioeconomic status. For example, blacks experience mortality rates up to about 42% higher than whites for these cancers. Furthermore, although overall death rates have been declining, the differential access to screening and care has aggravated disparities. Our purpose is to assess how the coverage policies of CMS and the United States Preventive Services Task Force (USPSTF) influence these disparities. Additionally, barriers are often encountered in accessing screening tests and receiving prompt treatment. To narrow, and potentially eliminate, outcomes disparities, CMS and USPSTF could consider revising their decision-making processes regarding coverage. Some options include (1) extending their evidence base to include observational studies that involve groups at higher risk; (2) lowering the threshold ages for screening to encompass differences in incidence; (3) CMS approving screening CT colonography coverage, which can even increase compliance with other screening tests; (4) clarifying and streamlining guidelines; (5) supporting research on improving access to screening; and (6) encouraging the development of more navigation services for URMs.

Testing for Verification Bias in Reported Malignancy Risks for Side-Branch Intraductal Papillary Mucinous Neoplasms: A Simulation Modeling Approach.

OBJECTIVE: The objective of our study was to test for the possibility that published malignancy risks for side-branch intraductal papillary mucinous neoplasms (IPMNs) are overestimates, likely due to verification bias. MATERIALS AND METHODS: We tested for possible verification bias using simulation modeling techniques. First, in age-defined hypothetical cohorts of 10 million persons, we projected the frequency of pancreatic ductal adenocarcinoma (PDAC) arising from side-branch IPMNs over 5 years using published estimates of their prevalence (4.4%) and rate of malignant transformation (1.9%). Second, we projected the total number of PDAC cases in corresponding cohorts over the same time horizon using national cancer registry data. For each cohort, we determined whether the percentage of all PDAC cases that arose from side-branch IPMNs (i.e., side-branch IPMN-associated PDAC cases) was clinically plausible using an upper limit of 10% to define plausibility, as estimated from the literature. Model assumptions and parameter uncertainty were evaluated in sensitivity analysis. RESULTS: Across all cohorts, percentages of side-branch IPMN-associated PDACs greatly exceeded 10%. In the base case (mean age = 55.7 years), 80% of PDAC cases arose from side-branch IPMNs (7877/9786). In the oldest cohort evaluated (mean age = 75 years), this estimate was 76% (14,227/18,714). In a secondary analysis, we found that if an upper limit threshold of 10% for side-branch IPMN-associated PDAC was imposed, the model-predicted rate of malignancy for side-branch IPMNs would be less than 0.24% over a 5-year time horizon, substantially lower than most literature-based estimates. CONCLUSION: Our results suggest that reported malignancy risks associated with side-branch IPMNs are likely to be overestimates and imply the presence of verification bias.

Management of Incidental Pituitary Findings on CT, MRI, and 18F-Fluorodeoxyglucose PET: A White Paper of the ACR Incidental Findings Committee.

The ACR Incidental Findings Committee presents recommendations for managing pituitary findings that are incidentally detected on CT, MRI and 18F-fluorodeoxyglucose PET. The Pituitary Subcommittee, which included radiologists practicing neuroradiology and an endocrinologist, developed this algorithm. The recommendations draw from published evidence and expert opinion and were finalized by informal iterative consensus. Algorithm branches successively categorize pituitary findings on the basis of imaging features. They terminate with an ascertainment of an indolent lesion (with sufficient confidence to discontinue follow-up) or a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. The goal is to improve the quality of care by providing guidance on how to manage incidentally detected pituitary findings.

Imaging Follow-up of Low-Risk Incidental Pancreas and Kidney Findings: Effects of Patient Age and Comorbidity on Projected Life Expectancy.

Purpose To determine the effects of patient age and comorbidity level on life expectancy (LE) benefits associated with imaging follow-up of Bosniak IIF renal cysts and pancreatic side-branch (SB) intraductal papillary mucinous neoplasms (IPMNs). Materials and Methods A decision-analytic Markov model to evaluate LE benefits was developed. Hypothetical cohorts with varied age (60-80 years) and comorbidities (none, mild, moderate, or severe) were evaluated. For each finding, LE projections from two strategies were compared: imaging follow-up and no imaging follow-up. Under follow-up, it was assumed that cancers associated with the incidental finding were successfully treated before they spread. For patients without follow-up, mortality risks from Bosniak IIF cysts (renal cell carcinoma) and SBIPMNs (pancreatic ductal adenocarcinoma) were incorporated. Model assumptions and parameter uncertainty were evaluated in sensitivity analysis. Results In the youngest, healthiest cohorts (age, 60 years; no comorbidities), projected LE benefits from follow-up were as follows: Bosniak IIF cyst, 6.5 months (women) and 5.8 months (men); SBIPMN, 6.4 months (women) and 5.3 months (men). Follow-up of Bosniak IIF cysts in 60-year-old women with severe comorbidities yielded a LE benefit of 3.9 months; in 80-year-old women with no comorbidities, the benefit was 2.8 months, and with severe comorbidities the benefit was 1.5 months. Similar trends were observed in men and for SBIPMN. Results were sensitive to the performance of follow-up for cancer detection; malignancy risks; and stage at presentation of malignant, unfollowed Bosniak IIF cysts. Conclusion With progression of age and comorbidity level, follow-up of low-risk incidental findings yields increasingly limited benefits for patients. © RSNA, 2018 Online supplemental material is available for this article.

Management of the Incidental Renal Mass on CT: A White Paper of the ACR Incidental Findings Committee.

The ACR Incidental Findings Committee (IFC) presents recommendations for renal masses that are incidentally detected on CT. These recommendations represent an update from the renal component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Renal Subcommittee, consisting of six abdominal radiologists and one urologist, developed this algorithm. The recommendations draw from published evidence and expert opinion and were finalized by informal iterative consensus. Each flowchart within the algorithm describes imaging features that identify when there is a need for additional imaging, surveillance, or referral for management. Our goal is to improve quality of care by providing guidance for managing incidentally detected renal masses.

Management of Incidental Liver Lesions on CT: A White Paper of the ACR Incidental Findings Committee.

The ACR Committee on Incidental Findings presents recommendations for managing liver lesions that are incidentally detected on CT. These recommendations represent an update from the liver component of the ACR 2010 white paper on managing incidental findings in the pancreas, adrenal glands, kidneys, and liver. The Liver Subcommittee-which included five abdominal radiologists, one hepatologist, and one hepatobiliary surgeon-developed this algorithm. The recommendations draw from published evidence and expert opinion and were finalized by informal iterative consensus. Algorithm branches categorize liver lesions on the basis of patient characteristics and imaging features. They terminate with an assessment of benignity or a specific follow-up recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. The goal is to improve the quality of care by providing guidance on how to manage incidentally detected liver lesions.

Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee.

The ACR Incidental Findings Committee presents recommendations for managing adrenal masses that are incidentally detected on CT or MRI. These recommendations represent an update to the adrenal component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Adrenal Subcommittee, constituted by abdominal radiologists and an endocrine surgeon, developed this algorithm. The algorithm draws from published evidence coupled with expert subspecialist opinion and was finalized by a process of iterative consensus. Algorithm branches categorize incidental adrenal masses on the basis of patient characteristics and imaging features. For each specified combination, the algorithm concludes with characterization of benignity or indolence (sufficient to discontinue follow-up) and/or a subsequent management recommendation. The algorithm addresses many, but not all, possible pathologies and clinical scenarios. Our goal is to improve the quality of patient care by providing guidance on how to manage incidentally detected adrenal masses.

Management of Incidental Pancreatic Cysts: A White Paper of the ACR Incidental Findings Committee.

The ACR Incidental Findings Committee (IFC) presents recommendations for managing pancreatic cysts that are incidentally detected on CT or MRI. These recommendations represent an update from the pancreatic component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Pancreas Subcommittee-which included abdominal radiologists, a gastroenterologist, and a pancreatic surgeon-developed this algorithm. The recommendations draw from published evidence and expert opinion, and were finalized by informal iterative consensus. Algorithm branches successively categorize pancreatic cysts based on patient characteristics and imaging features. They terminate with an ascertainment of benignity and/or indolence (sufficient to discontinue follow-up), or a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. Our goal is to improve quality of care by providing guidance on how to manage incidentally detected pancreatic cysts.

ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee.

Thyroid nodules are a frequent finding on neck sonography. Most nodules are benign; therefore, many nodules are biopsied to identify the small number that are malignant or require surgery for a definitive diagnosis. Since 2009, many professional societies and investigators have proposed ultrasound-based risk stratification systems to identify nodules that warrant biopsy or sonographic follow-up. Because some of these systems were founded on the BI-RADS® classification that is widely used in breast imaging, their authors chose to apply the acronym TI-RADS, for Thyroid Imaging, Reporting and Data System. In 2012, the ACR convened committees to (1) provide recommendations for reporting incidental thyroid nodules, (2) develop a set of standard terms (lexicon) for ultrasound reporting, and (3) propose a TI-RADS on the basis of the lexicon. The committees published the results of the first two efforts in 2015. In this article, the authors present the ACR TI-RADS Committee's recommendations, which provide guidance regarding management of thyroid nodules on the basis of their ultrasound appearance. The authors also describe the committee's future directions.

White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 2: Radiation Dose and Iodine Sensitivity.

This is the second of a series of 4 white papers that represent Expert Consensus Documents developed by the Society of Computed Body Tomography and Magnetic Resonance through its task force on dual-energy computed tomography. This paper, part 2, addresses radiation dose and iodine sensitivity in dual-energy computed tomography.

Gadoxetate Disodium enhanced spectral dual-energy CT for evaluation of cholangiocarcinoma: Preliminary data.

PURPOSE: Evaluate Gadoxetate Disodium enhanced dual-energy CT for visualization of perihilar cholangiocarcinoma by exploiting the hepatobiliary uptake of Gadoxetate Disodium and viewing images at the k-edge of gadolinium on the spectrum of simulated monoenergetic energies available with Dual Energy CT. MATERIAL AND METHODS: In this prospective, IRB-approved study in patients with suspected cholangiocarcinoma, subjects who underwent a clinically indicated Gadoxetate Disodium liver MRI were immediately scanned without further IV contrast administration using rapid kVp-switching dual energy CT (rsDECT). Initial Gadoxetate Disodium dose was the FDA approved clinical dose, 0.025 mmol/kg; after additional IRB/FDA approval, 10 subjects were scanned with 0.05 mmol/kg. Both 50 keV and 70 keV simulated monoenergetic images as well as gadolinium(-water) material density images were viewed qualitatively and measured quantitatively for gadolinium uptake in the hepatic parenchyma and any focal lesions identified. RESULTS: Of 18 subjects (mean age 55 years, 10M, 8F, weight 84 kg), eight were scanned with 0.025 mmol/kg (Group 1) and 10 with 0.05 mmol/kg Gadoxetate Disodium (Group 2). Five patients had cholangiocarcinoma (all in Group 1). On synthetic monoenergetic images using standard and double Gadoxetate Disodium dose, the liver parenchyma did not appear enhanced qualitatively. Comparison of mean hepatic parenchymal HU at 50 and 70 keV showed a measurable increase in attenuation at the lower viewing energy, which corresponded to the k-edge of gadolinium. No statistically significant difference was observed on quantitative gadolinium measurement of hepatic parenchyma for single versus double Gadoxetate Disodium dose using rsDECT gadolinium material density images. Of the five cholangiocarcinomas, the tumor to nontumoral hepatic tissue HU differences were 51.1 (32.2) (mean and std dev) and 49.0(26.5) at 50 and 70 keV, respectively. CONCLUSION: In this small pilot population, evaluation of potential hilar/perihilar cholangiocarcinoma using dual energy CT at both the single FDA-approved dose and double dose of gadolinium demonstrated observed differences in attenuation between the hepatic parenchyma and lesions. However, small sample size and heterogeneity of lesions warrants further investigation.

Rethinking Normal: Benefits and Risks of Not Reporting Harmless Incidental Findings.

The authors explore the benefits and risks of not reporting imaging findings that do not have clinical relevance, with the goal of developing recommendations to reduce their reporting. The authors review the example of incidentally detected, simple renal cysts (Bosniak category I), including medicolegal conditions required for such a shift in reporting practices to be acceptable. The authors propose four potential criteria for not reporting clinically unimportant findings and recommend that these criteria be debated in other contexts, so that they can be refined and implemented.

Thyroid Ultrasound Reporting Lexicon: White Paper of the ACR Thyroid Imaging, Reporting and Data System (TIRADS) Committee.

Ultrasound is the most commonly used imaging technique for the evaluation of thyroid nodules. Sonographic findings are often not specific, and definitive diagnosis is usually made through fine-needle aspiration biopsy or even surgery. In reviewing the literature, terms used to describe nodules are often poorly defined and inconsistently applied. Several authors have recently described a standardized risk stratification system called the Thyroid Imaging, Reporting and Data System (TIRADS), modeled on the BI-RADS system for breast imaging. However, most of these TIRADS classifications have come from individual institutions, and none has been widely adopted in the United States. Under the auspices of the ACR, a committee was organized to develop TIRADS. The eventual goal is to provide practitioners with evidence-based recommendations for the management of thyroid nodules on the basis of a set of well-defined sonographic features or terms that can be applied to every lesion. Terms were chosen on the basis of demonstration of consistency with regard to performance in the diagnosis of thyroid cancer or, conversely, classifying a nodule as benign and avoiding follow-up. The initial portion of this project was aimed at standardizing the diagnostic approach to thyroid nodules with regard to terminology through the development of a lexicon. This white paper describes the consensus process and the resultant lexicon.

Managing incidental thyroid nodules detected on imaging: white paper of the ACR Incidental Thyroid Findings Committee.

The incidental thyroid nodule (ITN) is one of the most common incidental findings on imaging studies that include the neck. An ITN is defined as a nodule not previously detected or suspected clinically, but identified by an imaging study. The workup of ITNs has led to increased costs from additional procedures, and in some cases, to increased risk to the patient because physicians are naturally concerned about the risk of malignancy and a delayed cancer diagnosis. However, the majority of ITNs are benign, and small, incidental thyroid malignancies typically have indolent behavior. The ACR formed the Incidental Thyroid Findings Committee to derive a practical approach to managing ITNs on CT, MRI, nuclear medicine, and ultrasound studies. This white paper describes consensus recommendations representing this committee's review of the literature and their practice experience.

Managing incidental findings on abdominal and pelvic CT and MRI, part 3: white paper of the ACR Incidental Findings Committee II on splenic and nodal findings.

This white paper describes splenic and nodal incidental findings found on CT and MRI. Recommendations for management are included. This represents the third of 4 such papers from the ACR Incidental Findings Committee II, which used a consensus method based on repeated reviews and revisions and a collective review and interpretation of relevant literature. Topics include descriptions of appearances of several types of splenic lesions and, the importance of size and distribution of lymph nodes. Flowcharts are provided for reference.