Practical Approaches to Quality Improvement for Radiologists.

Continuous quality improvement is a fundamental attribute of high-performing health care systems. Quality improvement is an essential component of health care, with the current emphasis on adding value. It is also a regulatory requirement, with reimbursements increasingly being linked to practice performance metrics. Practice quality improvement efforts must be demonstrated for credentialing purposes and for certification of radiologists in practice. Continuous quality improvement must occur for radiologists to remain competitive in an increasingly diverse health care market. This review provides an introduction to the main approaches available to undertake practice quality improvement, which will be useful for busy radiologists. Quality improvement plays multiple roles in radiology services, including ensuring and improving patient safety, providing a framework for implementing and improving processes to increase efficiency and reduce waste, analyzing and depicting performance data, monitoring performance and implementing change, enabling personnel assessment and development through continued education, and optimizing customer service and patient outcomes. The quality improvement approaches and underlying principles overlap, which is not surprising given that they all align with good patient care. The application of these principles to radiology practices not only benefits patients but also enhances practice performance through promotion of teamwork and achievement of goals.

How to perform a critical appraisal of diagnostic tests: 7 steps.

The critically appraised topic (CAT) is a format in evidence-based practice for sharing information. A CAT is a standardized way of summarizing the most current research evidence focused on a pertinent clinical question. Its aim is to provide both a critique of the most up-to-date retrieved research and an indication of the clinical relevance of results. A clinical question is initially generated following a patient encounter, which leads to and directs a literature search to answer the clinical question. Studies obtained from the literature search are assigned a level of evidence. This allows the most valid and relevant articles to be selected and to be critically appraised. The results are summarized, and this information is translated into clinically useful procedures and processes.

ACR Appropriateness Criteria® Workup of Pleural Effusion or Pleural Disease.

Pleural effusions are categorized as transudative or exudative, with transudative effusions usually reflecting the sequala of a systemic etiology and exudative effusions usually resulting from a process localized to the pleura. Common causes of transudative pleural effusions include congestive heart failure, cirrhosis, and renal failure, whereas exudative effusions are typically due to infection, malignancy, or autoimmune disorders. This document summarizes appropriateness guidelines for imaging in four common clinical scenarios in patients with known or suspected pleural effusion or pleural disease. 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.

Asymmetric expansion of aortic aneurysms on computed tomography imaging.

OBJECTIVE: To investigate whether wall growth during aneurysm development spares the aortic wall between the intercostal or lumbar arteries or, alternatively, is uniform around the circumference. METHODS: Computed tomography scans of 155 patients with aortic aneurysms (40 thoracic, 50 thoracoabdominal, and 65 abdominal) in a single hospital of a large academic institution were retrospectively inspected. Computed tomography studies of 100 control subjects (40 thoracic and 60 abdominal) were also reviewed. In all 255 patients, the ratio of the arc length between the origins of the intercostal or lumbar arteries (interbranch arc length) to the remainder of the aortic residual circumference was calculated. These ratios were compared between all subjects with aneurysms and the controls at each vertebral body level and between those with thoracic or thoracoabdominal or abdominal aneurysms and controls at each vertebral body level. RESULTS: Interbranch arc lengths and residual aortic circumferences were larger in aneurysm patients than in control subjects, but the differences were statistically significant only at T4 and from T8 to L4 (P = .009 to P < .001) and from T4 to L4 (P < .001), respectively. The ratio of interbranch arc length to residual circumference in aneurysmal aortas was significantly smaller than that in controls at 12 out of 13 levels from T4 to L4 (P = .004 to P < .001). There was a statistically significant smaller ratio at 8 out of 9 levels for thoracic aneurysms (P = .006 to P < .001), 12 out of 13 levels for thoracoabdominal aneurysms (P = .008 to P < .001), and 3 out of 4 levels for abdominal aneurysms compared with controls (P = .006 to P < .001). CONCLUSIONS: Wall growth in aortic aneurysms is asymmetric, with greater aneurysmal growth in the anterior aorta wall and relative sparing of the portion of aortic wall between the intercostal or lumbar arteries. The mechanisms effecting this asymmetric growth have not been fully characterized.

ACR Appropriateness Criteria® Lung Cancer Screening: 2022 Update.

Lung cancer remains the leading cause of cancer-related mortality for men and women in the United States. Screening for lung cancer with annual low-dose CT is saving lives, and the continued implementation of lung screening can save many more. In 2015, the CMS began covering annual lung screening for those who qualified based on the original United States Preventive Services Task Force (USPSTF) lung screening criteria, which included patients 55 to 77 year of age with a 30 pack-year history of smoking, who were either currently using tobacco or who had smoked within the previous 15 years. In 2021, the USPSTF issued new screening guidelines, decreasing the age of eligibility to 80 years of age and pack-years to 20. Lung screening remains controversial for those who do not meet the updated USPSTF criteria, but who have additional risk factors for the development of lung cancer. 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.

ACR Appropriateness Criteria® Incidentally Detected Indeterminate Pulmonary Nodule.

Incidental pulmonary nodules are common. Although the majority are benign, most are indeterminate for malignancy when first encountered making their management challenging. CT remains the primary imaging modality to first characterize and follow-up incidental lung nodules. This document reviews available literature on various imaging modalities and summarizes management of indeterminate pulmonary nodules detected incidentally. 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.

Aortic branch artery pseudoaneurysms accompanying aortic dissection. Part III: natural history.

PURPOSE: To document the natural history of branch artery pseudoaneurysms (BAPs), which are sequelae of aortic dissection with false lumen thrombosis that have been distinguished anatomically from penetrating ulcers. MATERIALS AND METHODS: Serial computed tomography (CT) scans in 50 patients with at least two CT scans greater than 1 month apart were retrospectively studied. Mean follow-up was 29 months, with longitudinal analyses of 119 BAPs. Changes in BAPs, false lumen thrombosis, and aortic diameter were assessed. RESULTS: No patient had an aortic rupture or other poor outcome. All BAPs eventually disappeared (ie, thrombosed), with 50% thrombosed within 18 months. Aortas were ectatic, with a mean diameter of 36 mm. There was no statistically significant change in total aortic diameters; however, there was a significant increase in true lumen diameters (P < .0001) and a significant decrease in false lumen thickness (P < .0001) at the level of the BAP over time (mean 50% reduction in maximum thickness of thrombosed false lumen). There were no significant associations between BAP thrombosis and vertebral level, presence of more than one BAP, presence of branch artery in communication with the BAP, history of smoking, diabetes mellitus or hypertension, or treatment with ß-blockers, other antihypertensive medication, statins, or anticoagulation therapy. After controlling for other variables, BAPs were less likely to thrombose if an ulcerlike projection was present (P = .003), in men (P = .02), in subjects with hypertension (P = .04), and in older patients (P = .05). CONCLUSIONS: Most BAPs spontaneously thrombose, and associated intramural hematoma regresses/disappears. Isolated BAPs were not associated with poor clinical outcomes.

ACR Appropriateness Criteria® Suspected Pulmonary Hypertension: 2022 Update.

Pulmonary hypertension may be idiopathic or related to a large variety of diseases. Various imaging examinations may be helpful in diagnosing and determining the etiology of pulmonary hypertension. Imaging examinations discussed in this document include chest radiography, ultrasound echocardiography, ventilation/perfusion scintigraphy, CT, MRI, right heart catheterization, and pulmonary angiography. The ACR 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 in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Staging and Follow-Up of Esophageal Cancer.

This document provides recommendations regarding the role of imaging in the staging and follow-up of esophageal cancer. For initial clinical staging, locoregional extent and nodal disease are typically assessed with esophagogastroduodenoscopy and esophageal ultrasound. FDG-PET/CT or CT of the chest and abdomen is usually appropriate for use in initial clinical staging as they provide additional information regarding distant nodal and metastatic disease. The detection of metastatic disease is critical in the initial evaluation of patients with esophageal cancer because it will direct patients to a treatment pathway centered on palliative radiation rather than surgery. For imaging during treatment, particularly neoadjuvant chemotherapy, FDG-PET/CT is usually appropriate, because some studies have found that it can provide information regarding primary lesion response, but more importantly it can be used to detect metastases that have developed since the induction of treatment. For patients who have completed treatment, FDG-PET/CT or CT of the chest and abdomen is usually appropriate for evaluating the presence and extent of metastases in patients with no suspected or known recurrence and in those with a suspected or known recurrence. The ACR 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.

How to perform a critically appraised topic: part 1, ask, search, and apply.

OBJECTIVE: This article outlines the first three steps involved in performing a critically appraised topic for studies of diagnostic tests: Ask, formulate a question; Search, search the literature; and Apply, apply a level of evidence to the retrieved literature. CONCLUSION: Critically appraised topics provide a structured approach to formulating a clinical question, effectively searching the literature, assigning a level of evidence to the obtained literature, appraising the literature, and making recommendations for clinical practice.

How to perform a critically appraised topic: part 2, appraise, evaluate, generate, and recommend.

OBJECTIVE: This article continues the discussion of a critically appraised topic started in Part 1. A critically appraised topic is a practical tool for learning and applying critical appraisal skills. This article outlines steps 4-7 involved in performing a critically appraised topic for studies of diagnostic tests: Appraise, Appraise the literature; Evaluate, evaluate the strength of the evidence from the literature; Generate, generate graphs of conditional probability; and Recommend, draw conclusions and make recommendations. CONCLUSION: For steps 4-7 of performing a critically appraised topic, the main study results are summarized and translated into clinically useful measures of accuracy, efficacy, or risk.

Challenges, controversies, and hot topics in pulmonary embolism imaging.

OBJECTIVE: The purpose of this article is to discuss the diagnostic role of pulmonary CT angiography (CTA) in the workup of pulmonary embolism (PE), including specific populations, and issues such as pulmonary CTA combined with indirect CT venography; radiation dose considerations; the management of isolated subsegmental PE; and new technologic developments, such as dual-source/dual-energy pulmonary CTA. CONCLUSION: The role of pulmonary CTA will continue to grow with the emergence of MDCT and dual-energy CT and their improved capabilities. However, the need for any given CT examination should always be justified on the basis of the individual patient's benefits and risks.

ACR Appropriateness Criteria® Chronic Cough.

Chronic cough is defined by a duration lasting at least 8 weeks. The most common causes of chronic cough include smoking-related lung disease, upper airway cough syndrome, asthma, gastroesophageal reflux disease, and nonasthmatic eosinophilic bronchitis. The etiology of chronic cough in some patients may be difficult to localize to an isolated source and is often multifactorial. The complex pathophysiology, clinical presentation, and variable manifestations of chronic cough underscore the challenges faced by clinicians in the evaluation and management of these patients. Imaging plays a role in the initial evaluation, although there is a lack of high-quality evidence guiding which modalities are useful and at what point in time the clinical evaluation should be performed. 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 include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Significant incidental cardiac disease on thoracic CT: what the general radiologist needs to know.

OBJECTIVE: Incidental cardiac findings are often found on chest CT studies, some of which may be clinically significant. The objective of this pictorial review is to illustrate and describe the appearances and management of the most frequently encountered significant cardiac findings on non-electrocardiographically gated thoracic CT. Most radiologists will interpret multidetector chest CT and should be aware of the imaging appearances, significance, and the appropriate next management steps, when incidental significant cardiac disease is encountered on thoracic CT. CONCLUSION: This article reviews significant incidental cardiac findings which may be encountered on chest CT studies. After completing this review, the reader should not only be familiar with recognizing clinically significant cardiac findings seen on thoracic CT examinations but also have the confidence to direct their further management.

Solitary pulmonary nodules: meta-analytic comparison of cross-sectional imaging modalities for diagnosis of malignancy.

PURPOSE: To perform a meta-analysis to estimate the diagnostic accuracy of dynamic contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging, fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET), and technetium 99m ((99m)Tc) depreotide single photon emission computed tomography (SPECT) for evaluation of solitary pulmonary nodules (SPNs). MATERIALS AND METHODS: Data sources were studies published in PubMed between January 1990 and December 2005. The selected investigations were comparative and noncomparative diagnostic cohort studies to examine the operating characteristics of the four imaging modalities for evaluation of SPNs, involving at least 10 enrolled participants with histologic confirmation and having sufficient data to calculate contingency tables. A random coefficient binary regression model with disease probability conditioned on test results was used to summarize test performance and construct summary receiver operating characteristic (ROC) curves. Sensitivities, specificities, predictive values, diagnostic odds ratios, and areas under the ROC curve were calculated. RESULTS: Forty-four studies--10 dynamic CT, six dynamic MR, 22 FDG PET, and seven (99m)Tc-depreotide SPECT--met the inclusion criteria. (One study was included in both the FDG PET and SPECT groups.) Sensitivities, specificities, positive predictive values, negative predictive values, diagnostic odds ratios, and areas under the ROC curve were, respectively, 0.93 (95% confidence interval [CI]: 0.88, 0.97), 0.76 (95% CI: 0.68, 0.97), 0.80 (95% CI: 0.74, 0.86), 0.95 (95% CI: 0.93, 0.98), 39.91 (95% CI: 1.21, 81.04), and 0.93 (95% CI: 0.81, 0.97) for dynamic CT; 0.94 (95% CI: 0.91, 0.97), 0.79 (95% CI: 0.73, 0.86), 0.86 (95% CI: 0.83, 0.89), 0.93 (95% CI: 0.90, 0.96), 60.59 (95% CI: 5.56, 115.62), and 0.94 (95% CI: 0.83, 0.98) for dynamic MR; 0.95 (95% CI: 0.93, 0.98), 0.82 (95% CI: 0.77, 0.88), 0.91 (95% CI: 0.88, 0.93), 0.90 (95% CI: 0.85, 0.94), 97.31 (95% CI: 6.26, 188.37), and 0.94 (95% CI: 0.83, 0.98) for FDG PET; and 0.95 (95% CI: 0.93, 0.97), 0.82 (95% CI: 0.78, 0.85), 0.90 (95% CI: 0.83, 0.97), 0.91 (95% CI: 0.84, 0.98), 84.50 (95% CI: 34.28, 134.73), and 0.94 (95% CI: 0.83, 0.98) for (99m)Tc-depreotide SPECT. CONCLUSION: Dynamic CT and MR, FDG PET, and (99m)Tc-depreotide SPECT are noninvasive and accurate in distinguishing malignant from benign SPNs; differences among these tests are nonsignificant.

Teaching and Assessing Professionalism in Radiology: Resources and Scholarly Opportunities to Contribute to Required Expectations.

Teaching and assessing trainees' professionalism now represents an explicit expectation for Accreditation Council Graduate Medical Education-accredited radiology programs. Challenges to meeting this expectation include variability in defining the construct of professionalism; limits of traditional teaching and assessment methods, used for competencies historically more prominent in medical education, for professionalism; and emerging expectations for credible and feasible professionalism teaching and assessment practices in the current context of health-care training and practice. This article identifies promising teaching resources and methods that can be used strategically to augment traditional teaching of the cognitive basis for professionalism, including role modeling, case-based scenarios, debriefing, simulations, narrative medicine (storytelling), guided discussions, peer-assisted learning, and reflective practice. This article also summarizes assessment practices intended to promote learning, as well as to inform how and when to assess trainees as their professional identities develop over time, settings, and autonomous practice, particularly in terms of measurable behaviors. This includes assessment tools (including mini observations, critical incident reports, and appreciative inquiry) for authentic assessment in the workplace; engaging multiple sources (self-, peer, other health professionals, and patients) in assessment; and intentional practices for trainees to take responsibility for seeking our actionable feedback and reflection. This article examines the emerging evidence of the feasibility and value added of assessment of medical competency milestones, including professionalism, coordinated by the Accreditation Council Graduate Medical Education in radiology and other medical specialties. Radiology has a strategic opportunity to contribute to scholarship and inform policies in professionalism teaching and assessment practices.

Designing a Curriculum for Professionalism and Ethics Within Radiology: Identifying Challenges and Expectations.

Although professionalism and ethics represent required competencies, they are more challenging than other competencies to design a curriculum for and teach. Reasons include variability in agreed definitions of professionalism within medicine and radiology. This competency is also framed differently whether as roles, duties, actions, skills, behavior, beliefs, and attitudes. Standardizing a curriculum in professionalism is difficult because each learner's (medical student/resident) professional experiences and interactions will be unique. Professionalism is intertwined throughout all (sub) specialties and areas and its teaching cannot occur in isolation as a standalone curriculum. In the past, professionalism was not emphasized enough or at all, with global (or no) assessments, with the potential effect of trainees not valuing it. Although we can teach it formally in the classroom and informally in small groups, much of professionalism is witnessed and learned as "hidden curricula". The formal, informal, and hidden curricula often contradict each other creating confusion, disillusion, and cynicism in trainees. The corporatization of medicine pressurizes us to increase efficiency (throughput) with less focus on aspects of professionalism that add value, creating a disjoint between what we do in practice and preach to trainees. Progressively, expectations for our curriculum include providing evidence for the impacts of our efforts on patient outcomes. Generational differences in the perception of professionalism and the increasingly diverse and multicultural society in which we live affects our interpretation of professionalism, which can add to confusion and misunderstanding. The objectives of this article are to outline challenges facing curriculum design in professionalism and to make suggestions to help educators avoid or overcome them.

How to Perform a Systematic Review and Meta-analysis of Diagnostic Imaging Studies.

A systematic review is a comprehensive search, critical evaluation, and synthesis of all the relevant studies on a specific (clinical) topic that can be applied to the evaluation of diagnostic and screening imaging studies. It can be a qualitative or a quantitative (meta-analysis) review of available literature. A meta-analysis uses statistical methods to combine and summarize the results of several studies. In this review, a 12-step approach to performing a systematic review (and meta-analysis) is outlined under the four domains: (1) Problem Formulation and Data Acquisition, (2) Quality Appraisal of Eligible Studies, (3) Statistical Analysis of Quantitative Data, and (4) Clinical Interpretation of the Evidence. This review is specifically geared toward the performance of a systematic review and meta-analysis of diagnostic test accuracy (imaging) studies.

Reliability of MDCT in characterizing pulmonary venous drainage, diameter and distance to first bifurcation: an interobserver study.

RATIONALE AND OBJECTIVES: To evaluate the interobserver agreement of readers in evaluating pulmonary venous anatomy and in measuring pulmonary vein ostial diameters and distance to first bifurcation. MATERIALS AND METHODS: This study was approved by our institutional review board. Thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax were retrospectively reviewed in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean, 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. For each patient, pulmonary venous anatomy and drainage patterns including the number of venous ostia was assessed independently by experienced cardiothoracic radiologists. Pulmonary vein ostial diameter and distance to the first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior), the middle lobe pulmonary vein, and any anomalous pulmonary veins (common trunks and accessory veins) were measured independently at a workstation. Interreader assessment of pulmonary venous anatomy was evaluated using the Kappa statistic. Interreader variation in measurements of venous diameter and distant to first bifurcation were estimated by Bland-Altman plots and Pitman's test of difference in variance. RESULTS: Very good to excellent interreader agreement in detection of anomalous pulmonary venous anatomy, middle lobe pulmonary venous drainage, and other thoracic venous anomalies. No significant variation between readers in pulmonary vein ostial diameter measurements for the four major and middle lobe pulmonary veins, or the anomalous pulmonary veins. Significant interreader variability was noted in measurements of the pulmonary vein distance to first bifurcation for the right inferior (P = .017), middle lobe (P = .005), and left inferior (P = .015) pulmonary veins. CONCLUSIONS: There is excellent interobserver agreement when evaluating normal and anomalous pulmonary venous drainage patterns, and when measuring normal or anomalous pulmonary vein diameters. However, measurements of distances to first bifurcation were less reliable across readers.

Normative analysis of pulmonary vein drainage patterns on multidetector CT with measurements of pulmonary vein ostial diameter and distance to first bifurcation.

RATIONALE AND OBJECTIVES: To document the frequency of normal and anomalous drainage patterns of the pulmonary veins, and to establish normal values for pulmonary vein ostial diameters, and distance to first bifurcation using multidetector computed tomography, as pertinent to ablation procedures for atrial fibrillation. MATERIALS AND METHODS: Two cardiothoracic radiologists retrospectively reviewed thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. Pulmonary vein anatomy was based on both the number of venous ostia and the drainage patterns of pulmonary veins. Pulmonary vein ostial diameters and distance to first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior) and any additional pulmonary veins were measured at a workstation using both axial images and multiplanar reconstructions by two experienced cardiothoracic radiologists; the mean pulmonary vein diameter and the shortest distance to first bifurcation of the two measurements are reported. RESULTS: The majority of patients, 82% (164 patients) had four pulmonary veins, with a superior and inferior ostium on the right and a superior and inferior ostium on the left. Of the remainder, 9% (18 patients) had five veins, 4.5% (9 patients) had three veins, 3% (6 patients) had two anomalies each, and 0.5% (1 patient) had three anomalies. The middle lobe pulmonary vein drained into the right superior pulmonary vein in 83.5% of patients, directly into the left atrium in 11% of patients, and into the right inferior pulmonary vein in 5.5% of patients; 6.5% of patients had a single left pulmonary vein ostium. Mean pulmonary vein diameters with 95% confidence intervals at the ostia were as follows: right superior 17.6 (13.64-15.36) mm; left superior 16.6 (16.03-17.08) mm; right inferior 17.1 (16.58-17.55) mm; left inferior 14.8 (14.25-15.27) mm, and independent middle lobe 8.6 (8.27-8.86) mm. Mean distance to first bifurcation with 95% confidence intervals were: right superior 14.5 (17.02-18.23) mm; left superior 17.6 (16.63-18.53) mm; right inferior 7.0 (6.49-7.46) mm; left inferior 13.5 (12.83-14.16) mm, and independent middle lobe 8.4 (7.7-9.17) mm. CONCLUSION: Thin-section thoracic computed tomography demonstrates a greater variability of pulmonary venous drainage than previously described. There is greater variability of the right lung venous drainage compared to the left lung. Eighty-two percent of people have four standard pulmonary veins. There is significant variability in pulmonary vein diameter and distance to first bifurcation.