Evaluation of ChatGPT-Generated Educational Patient Pamphlets for Common Interventional Radiology Procedures.

RATIONALE AND OBJECTIVES: This study aimed to evaluate the accuracy and reliability of educational patient pamphlets created by ChatGPT, a large language model, for common interventional radiology (IR) procedures. METHODS AND MATERIALS: Twenty frequently performed IR procedures were selected, and five users were tasked to independently request ChatGPT to generate educational patient pamphlets for each procedure using identical commands. Subsequently, two independent radiologists assessed the content, quality, and accuracy of the pamphlets. The review focused on identifying potential errors, inaccuracies, the consistency of pamphlets. RESULTS: In a thorough analysis of the education pamphlets, we identified shortcomings in 30% (30/100) of pamphlets, with a total of 34 specific inaccuracies, including missing information about sedation for the procedure (10/34), inaccuracies related to specific procedural-related complications (8/34). A key-word co-occurrence network showed consistent themes within each group of pamphlets, while a line-by-line comparison at the level of users and across different procedures showed statistically significant inconsistencies (P < 0.001). CONCLUSION: ChatGPT-generated education pamphlets demonstrated potential clinical relevance and fairly consistent terminology; however, the pamphlets were not entirely accurate and exhibited some shortcomings and inter-user structural variabilities. To ensure patient safety, future improvements and refinements in large language models are warranted, while maintaining human supervision and expert validation.

ChatGPT in radiology: A systematic review of performance, pitfalls, and future perspectives.

PURPOSE: The purpose of this study was to systematically review the reported performances of ChatGPT, identify potential limitations, and explore future directions for its integration, optimization, and ethical considerations in radiology applications. MATERIALS AND METHODS: After a comprehensive review of PubMed, Web of Science, Embase, and Google Scholar databases, a cohort of published studies was identified up to January 1, 2024, utilizing ChatGPT for clinical radiology applications. RESULTS: Out of 861 studies derived, 44 studies evaluated the performance of ChatGPT; among these, 37 (37/44; 84.1%) demonstrated high performance, and seven (7/44; 15.9%) indicated it had a lower performance in providing information on diagnosis and clinical decision support (6/44; 13.6%) and patient communication and educational content (1/44; 2.3%). Twenty-four (24/44; 54.5%) studies reported the proportion of ChatGPT's performance. Among these, 19 (19/24; 79.2%) studies recorded a median accuracy of 70.5%, and in five (5/24; 20.8%) studies, there was a median agreement of 83.6% between ChatGPT outcomes and reference standards [radiologists' decision or guidelines], generally confirming ChatGPT's high accuracy in these studies. Eleven studies compared two recent ChatGPT versions, and in ten (10/11; 90.9%), ChatGPTv4 outperformed v3.5, showing notable enhancements in addressing higher-order thinking questions, better comprehension of radiology terms, and improved accuracy in describing images. Risks and concerns about using ChatGPT included biased responses, limited originality, and the potential for inaccurate information leading to misinformation, hallucinations, improper citations and fake references, cybersecurity vulnerabilities, and patient privacy risks. CONCLUSION: Although ChatGPT's effectiveness has been shown in 84.1% of radiology studies, there are still multiple pitfalls and limitations to address. It is too soon to confirm its complete proficiency and accuracy, and more extensive multicenter studies utilizing diverse datasets and pre-training techniques are required to verify ChatGPT's role in radiology.

How AI Responds to Common Lung Cancer Questions: ChatGPT vs Google Bard.

Background The recent release of large language models (LLMs) for public use, such as ChatGPT and Google Bard, has opened up a multitude of potential benefits as well as challenges. Purpose To evaluate and compare the accuracy and consistency of responses generated by publicly available ChatGPT-3.5 and Google Bard to non-expert questions related to lung cancer prevention, screening, and terminology commonly used in radiology reports based on the recommendation of Lung Imaging Reporting and Data System (Lung-RADS) v2022 from American College of Radiology and Fleischner society. Materials and Methods Forty of the exact same questions were created and presented to ChatGPT-3.5 and Google Bard experimental version as well as Bing and Google search engines by three different authors of this paper. Each answer was reviewed by two radiologists for accuracy. Responses were scored as correct, partially correct, incorrect, or unanswered. Consistency was also evaluated among the answers. Here, consistency was defined as the agreement between the three answers provided by ChatGPT-3.5, Google Bard experimental version, Bing, and Google search engines regardless of whether the concept conveyed was correct or incorrect. The accuracy among different tools were evaluated using Stata. Results ChatGPT-3.5 answered 120 questions with 85 (70.8%) correct, 14 (11.7%) partially correct, and 21 (17.5%) incorrect. Google Bard did not answer 23 (19.1%) questions. Among the 97 questions answered by Google Bard, 62 (51.7%) were correct, 11 (9.2%) were partially correct, and 24 (20%) were incorrect. Bing answered 120 questions with 74 (61.7%) correct, 13 (10.8%) partially correct, and 33 (27.5%) incorrect. Google search engine answered 120 questions with 66 (55%) correct, 27 (22.5%) partially correct, and 27 (22.5%) incorrect. The ChatGPT-3.5 is more likely to provide correct or partially answer than Google Bard, approximately by 1.5 folds (OR = 1.55, P = 0.004). ChatGPT-3.5 and Google search engine were more likely to be consistent than Google Bard by approximately 7 and 29 folds (OR = 6.65, P = 0.002 for ChatGPT and OR = 28.83, P = 0.002 for Google search engine, respectively). Conclusion Although ChatGPT-3.5 had a higher accuracy in comparison with the other tools, neither ChatGPT nor Google Bard, Bing and Google search engines answered all questions correctly and with 100% consistency.

Cardiac Outpouchings: Practical Approach to Normal Variants and Pathologic Conditions at CT and MRI.

Numerous entities, both structural and pathologic, can manifest as a contrast material- or blood-filled cardiac outpouching at imaging. These outpouchings often resemble one another and are frequently unfamiliar to imagers and clinicians, creating uncertainty when detected. Furthermore, the diagnostic criteria for conditions such as hernia, aneurysm, pseudoaneurysm, and diverticulum have not been consistently applied in studies and reports cited in the literature describing these outpouchings, adding to the confusion among general and cardiothoracic imagers. Pouches and outpouchings are commonly found incidentally on thoracic and abdominal CT scans obtained for other reasons. Many pouches and outpouchings can be confidently diagnosed or ignored at routine imaging, whereas others may require further evaluation with electrocardiographically gated CT, cardiac MRI, or echocardiography for a more definitive diagnosis. It is easiest to group and diagnose these entities on the basis of their cardiac chamber location or their involvement with the interatrial and interventricular septa. Ancillary features, such as motion, morphology, neck and body size, presence or absence of thrombus, and late gadolinium enhancement characteristics, are important in reaching a correct diagnosis. The aim of this article is to provide a practical guide to pouches and outpouchings of the heart. Each entity is defined according to its cause, imaging characteristics, clinical significance, and relevant associated findings. Mimics of cardiac pouches and outpouchings such as the Bachmann bundle, atrial veins, and thebesian vessels also are briefly discussed. Quiz questions for this article are available in the supplemental material. ©RSNA, 2023.

Contrast-enhanced MR Angiography without Gadolinium-based Contrast Material: Clinical Applications Using Ferumoxytol.

Vascular imaging can be challenging because of the wide variability of contrast dynamics in different vascular territories and potential safety concerns in patients with renal insufficiency or allergies. Off-label diagnostic use of ferumoxytol, a superparamagnetic iron nanoparticle approved for therapy, is a promising alternative to gadolinium-based contrast agents for MR angiography (MRA). Ferumoxytol has exhibited a reassuring safety profile when used within the dose range recommended for diagnostic imaging. Because of its prolonged and stable intravascular residence, ferumoxytol can be used in its steady-state distribution for a wide variety of imaging indications, including some where conventional MRA is unreliable. In this article, authors discuss some of the major vascular applications of ferumoxytol and highlight how it may be used to provide highly diagnostic images and improve the quality, workflow, and reliability of vascular imaging. Keywords: MR Angiography, MRI Contrast Agent, Cardiac, Vascular © RSNA, 2022.

CT evaluation of unrepaired/incidental congenital cardiovascular diseases in adults.

Congenital heart disease (CHD) affects approximately one million people in the USA with the number increasing by 5% each year. Patients are usually both diagnosed and treated in infancy, however many of them may have subclinical CHD that remains undiagnosed until late adulthood. Patients with complex CHD tend to be symptomatic and are diagnosed at a younger age than those with a single defect. CHDs can be divided into three categories, including cardiac, great vessels and coronary artery anomalies. Recent advances in computed tomography (CT) technology with faster acquisition time and improved spatial resolution allow for detailed evaluation of cardiac morphology and function. The concomitant increased utilization of CT has simultaneously led to more sensitive detection and more thorough diagnosis of CHD. Recognition of and understanding the imaging attributes specific to each anomaly is important for radiologists in order to make a correct and definite diagnosis. This article reviews the spectrum of CHDs, which persist into adulthood that may be encountered by radiologists on CT.

Vascularized Lymph Node Transfer: A Primer for the Radiologist.

Lymphedema, the accumulation of lymphatic fluid in the tissues, is a chronic disease and a major cause of long-term morbidity and disability. Lymphedema is usually a secondary condition, often caused by prior oncologic therapy, such as surgery for cancers, radiation therapy, and chemotherapy. Treatment for lymphedema has traditionally been conservative and limited, but new surgical and microsurgical procedures have arisen in recent years. Vascularized lymph node transfer (VLNT) is one of the most promising new microsurgeries. VLNT involves the transfer of functional lymph nodes (LNs) from a healthy donor site to an area of the body with damaged or diseased lymphatic drainage. The goal of the transplant is to restore physiologic LN drainage and improve lymphedema. Donor LNs are commonly found in the groin, axilla, neck, omentum, or submental region. Imaging can be used for preoperative planning to identify donor sites with the richest number of LNs. This can help identify those patients who may be candidates for VLNT and can help identify the best anatomic site for surgical harvest in those candidates. Imaging can be performed with US, CT, or MRI. VLNT preoperative imaging often requires acquisition techniques and reconstruction parameters that differ from those used in routine diagnostic imaging. Furthermore, to properly identify target LNs, the radiologist must be aware of surgical anatomic landmarks. Online supplemental material is available for this article. ©RSNA, 2020.

Recent Innovations in Renal Vascular Imaging.

Noninvasive imaging of the vascular renal system is a common request in diagnostic radiology. Typical indications include suspected renovascular hypertension, vasculitis, neoplasm, vascular malformation, and structural diseases of the kidney. Profound knowledge of the renal anatomy, including vascular supply and variants, is mandatory for radiologists and allows for optimized protocolling and interpretation of imaging studies. Besides renal ultrasound, computed tomography and MR imaging are commonly requested cross-sectional studies for renal and renal vascular imaging. This article discusses basic renal vascular anatomy, common imaging findings, and current and potential future imaging protocols for various renovascular pathologic conditions.

Abdominal wall and pelvic hernias: classic and unusual hernias and their mimics.

Abdominal and pelvic wall hernias are classically defined as a weakness or opening of the muscular wall through which abdominal or pelvic tissues protrude. The aim of this manuscript is to review the imaging findings of abdominal and pelvic wall hernias and their mimics and to discuss pearls and pitfalls for accurately diagnosing and classifying these entities.

Myocardial Radiomics in Cardiac MRI.

OBJECTIVE. The purpose of this article is to review the nascent field of radiomics in cardiac MRI. CONCLUSION. Cardiac MRI produces a large number of images in a fairly inefficient manner with sometimes limited clinical application. In the era of precision medicine, there is increasing need for imaging to account for a broader array of diseases in an efficient and objective manner. Radiomics, the extraction and analysis of quantitative imaging features from medical imaging, may offer potential solutions to this need.

Tricuspid Annular Diameter Measurement on Routine Chest CT Can Detect Significant Tricuspid Regurgitation.

OBJECTIVE. The objective of this study was to determine if moderate to severe tricuspid regurgitation (TR) can be predicted on routine non-ECG-gated CT images of the chest with contrast agent. MATERIALS AND METHODS. Non-ECG-gated CT images of the chest in 674 people who had undergone echocardiography within 24 hours of CT were retrospectively reviewed. CT images were reviewed, and measurements of the tricuspid annular diameter were recorded. Echocardiogram reports were independently reviewed, and the presence and severity of TR was recorded. TR was graded in a multiparametric approach using a combination of qualitative, quantitative, and objective measures. TR grades of either "moderate" or "severe" were considered significant, and grades reported as "no regurgitation," "trace," "trivial," or "mild" were considered insignificant. RESULTS. The overall prevalence of significant (moderate or severe) TR was 15.0% (10.7% prevalence in men and 19.8% in women). Using ≥ 41 mm as a cut point on CT, the prediction accuracy reached an AUC of 0.92 (95% CI, 0.89-0.96). Specificity was 96.5% (95% CI, 95.0-97.9%), sensitivity was 75.7% (95% CI, 67.6-83.8%), positive predictive value was 80.2%, and negative predictive value was 95.5%. CONCLUSION. Using a cut point of ≥ 41 mm, measurement of the tricuspid valve annulus on routine CT of the chest can predict moderate to severe TR with a specificity of 96.5% and sensitivity of 75.7%. Measurements below threshold had a 95.5% negative predictive value. Tricuspid annular diameter can be measured on routine contrast-enhanced CT images of the chest, and, when above threshold, further evaluation with echocardiography should be recommended.

Radiomics in Pulmonary Lesion Imaging.

OBJECTIVE: Diagnostic imaging has traditionally relied on a limited set of qualitative imaging characteristics for the diagnosis and management of lung cancer. Radiomics-the extraction and analysis of quantitative features from imaging-can identify additional imaging characteristics that cannot be seen by the eye. These features can potentially be used to diagnose cancer, identify mutations, and predict prognosis in an accurate and noninvasive fashion. This article provides insights about trends in radiomics of lung cancer and challenges to widespread adoption. CONCLUSION: Radiomic studies are currently limited to a small number of cancer types. Its application across various centers are nonstandardized, leading to difficulties in comparing and generalizing results. The tools available to apply radiomics are specialized and limited in scope, blunting widespread use and clinical integration in the general population. Increasing the number of multicenter studies and consortiums and inclusion of radiomics in resident training will bring more attention and clarity to the growing field of radiomics.

Image Predictors of Treatment Outcome after Thoracic Aortic Dissection Repair.

Treatment of thoracic aortic dissection remains highly challenging and is rapidly evolving. Common classifications of thoracic aortic dissection include the Stanford classification (types A and B) and the DeBakey classification (types I to III), as well as a new supplementary classification geared toward endovascular decision making. By using various imaging techniques, the extent of the dissection, the location of the primary intimal tear, the shape of the aortic arch, and the zonal involvement of the aortic arch-factors that affect the treatment strategy-can easily be identified. Thoracic endovascular aortic repair (TEVAR) is generally performed in two groups of patients: (a) those with a surgically repaired type A dissection, and (b) those with a complicated type B dissection. Several imaging findings can help predict the course of remodeling of the dissected aorta after a repaired type A dissection and TEVAR. A spectrum of imaging findings exist with regard to favorable (positive) or failing (negative) remodeling. A schematic model with imaging support allows the classification of important causes of failing remodeling into proximal and distal groups, on the basis of the origin of the refilling of the false lumen and the underlying pathophysiology of pressurization. Refilling of the false lumen of the aorta after repair of a type A dissection is usually secondary to a persistent intimal tear at the aortic arch, a leak of the distal graft anastomosis, or refilling from the false lumen of a dissected aortic arch vessel. After TEVAR, false lumen refilling is most commonly due to an incomplete seal of the proximal landing related to the aortic tortuosity, an arch branch stump, a supra-arch chimney stent, or the TEVAR technique. Online supplemental material is available for this article. ©RSNA, 2018.

Anatomical Basis of the Gastroepiploic Vascularized Lymph Node Transfer: A Radiographic Evaluation Using Computed Tomographic Angiography.

BACKGROUND: The omentum, nourished by the gastroepiploic vessels, has gained popularity as an option for vascularized lymph node transfer. The anatomy of the gastroepiploic vessels, omentum, and lymph nodes has not been investigated. The purpose of this article is to describe the right gastroepiploic artery and related structures by using computed tomographic angiography. METHODS: A retrospective analysis was conducted on 34 patients who underwent computed tomographic angiography. Statistical models were applied to identify right gastroepiploic artery and lymph node anatomical characteristics. RESULTS: The right gastroepiploic artery was identified in 33 of 34 patients. It was found to have a diameter of 2.49 ± 0.66 mm at its origin. The gastroduodenal artery length before right gastroepiploic artery takeoff was 3.09 ± 1.31 cm. Twenty-five patients had lymph nodes in the right gastroepiploic artery lymphosome. There were 2.7 ± 2.12 lymph nodes identified per patient. The distance from the right gastroepiploic artery origin to the most proximal lymph node was 3.99 ± 2.21 cm. The distance from the gastroepiploic artery origin to the third lymph node was 9.12 ± 5.06 cm. Each lymph node was within 7.00 ± 6.2 mm of the right gastroepiploic artery. CONCLUSIONS: When using the right gastroepiploic artery donor site for vascularized lymph node transfer, the plastic surgeon should anticipate using a pedicle length of 4 cm, a total flap length of 9 cm, and 3 cm of surrounding tissue to obtain at least three lymph nodes for transfer. Computed tomographic angiography is an effective imaging modality that can be used for patient-specific surgical navigation before vascularized lymph node transfer.

Forward-Projected Model-Based Iterative Reconstruction in Screening Low-Dose Chest CT: Comparison With Adaptive Iterative Dose Reduction 3D.

OBJECTIVE: The objective of this study is to compare forward-projected model-based iterative reconstruction solution (FIRST), a newer fully iterative CT reconstruction method, with adaptive iterative dose reduction 3D (AIDR 3D) in low-dose screening CT for lung cancer. Differences in image noise, image quality, and pulmonary nodule detection, size, and characterization were specifically evaluated. MATERIALS AND METHODS: Low-dose chest CT images obtained for 50 consecutive patients between December 2015 and January 2016 were retrospectively reviewed. Images were reconstructed using FIRST and AIDR 3D for both lung and soft-tissue reconstruction. Images were independently reviewed to assess image noise, subjective image quality (with use of a 5-point Likert scale, with 1 denoting far superior image quality; 2, superior quality; 3, equivalent quality; 4, inferior quality; and 5, far inferior quality), pulmonary nodule count, size of the largest pulmonary nodule, and characterization of the largest pulmonary nodule (i.e., solid, part solid, or ground glass). RESULTS: Across all 50 cases, measured image noise was lower with FIRST than with AIDR 3D (lung window, 44% reduction, 41 ± 7 vs 74 ± 8 HU, respectively; soft-tissue window, 32% reduction, 11 ± 2 vs 16 ± 2 HU, respectively). Readers subjectively rated images obtained with FIRST as comparable to images obtained with AIDR 3D (mean [± SD] Likert score for FIRST vs AIDR 3D, 3.2 ± 0.3 for soft-tissue reconstructions and 3.0 ± 0.3 for lung reconstructions). For each reader, very good agreement regarding nodule count was noted between FIRST and AIDR 3D (interclass correlation coefficient [ICC], 0.83 for reader 1 and 0.78 for reader 2). Excellent agreement regarding nodule size (ICC, 0.99 for reader 1 and 0.99 for reader 2) and characterization of the largest nodule (kappa value, 0.92 for reader 1 and 0.82 for reader 2) also existed. CONCLUSION: Images reconstructed with FIRST are superior to those reconstructed AIDR 3D with regard to image noise and are equivalent with regard to subjective image quality, pulmonary nodule count, and nodule characterization.

Comprehensive Cross-sectional Imaging of the Pulmonary Veins.

The pulmonary veins carry oxygenated blood from the lungs to the heart, but their importance to the radiologist extends far beyond this seemingly straightforward function. The anatomy of the pulmonary veins is variable among patients, with several noteworthy variant and anomalous patterns, including supernumerary pulmonary veins, a common ostium, anomalous pulmonary venous return, and levoatriocardinal veins. Differences in pulmonary vein anatomy and the presence of variant or anomalous anatomy can be of critical importance, especially for preoperative planning of pulmonary and cardiac surgery. The enhancement or lack of enhancement of the pulmonary veins can be a clue to clinically important disease, and the relationship of masses to the pulmonary veins can herald cardiac invasion. The pulmonary veins are also an integral part of thoracic interventions, including lung transplantation, pneumonectomy, and radiofrequency ablation for atrial fibrillation. This fact creates a requirement for radiologists to have knowledge of the pre- and postoperative imaging appearances of the pulmonary veins. Many of these procedures are associated with important potential complications involving the pulmonary veins, for which diagnostic imaging plays a critical role. A thorough knowledge of the pulmonary veins and a proper radiologic approach to their evaluation is critical for the busy radiologist who must incorporate the pulmonary veins into a routine "search pattern" at computed tomography (CT) and magnetic resonance imaging. This article is a comprehensive CT-based imaging review of the pulmonary veins, including their embryology, anatomy (typical and anomalous), surgical implications, pulmonary vein thrombosis, pulmonary vein stenosis, pulmonary vein pseudostenosis, and the relationship of tumors to the pulmonary veins. Online supplemental material is available for this article. ©RSNA, 2017.

Fibrous Skeleton of the Heart: Anatomic Overview and Evaluation of Pathologic Conditions with CT and MR Imaging.

The fibrous skeleton is concentrated at the base of the ventricular mass. It provides electrical insulation at the atrioventricular level and fibrous continuity for the leaflets of the mitral, aortic, and tricuspid valves. Its components include the fibrous trigones, the fibrous area of aortic-mitral continuity, the subvalvar collar of the mitral valve, the membranous septum, the interleaflet triangles, the tendon of Todaro, and likely the conus ligament. The majority of the mitral annulus is fibrous, but the only true fibrous part of the tricuspid annulus is where the valvar leaflets are attached to the central fibrous body. At the aortic annulus, the fibrous elements support only the noncoronary aortic sinus and parts of the right and left coronary sinuses. The ring-shaped annulus of the arterioventricular valves as localized with imaging techniques (imaging annulus) differs from the crown-shaped hemodynamic annulus of the arterial valves. The imaging annulus corresponds to the plane passing through the nadirs of the hinge-lines of the leaflets. The hinges of the pulmonary valve are not part of the fibrous skeleton. Computed tomography (CT) and magnetic resonance (MR) imaging are excellent modalities for evaluation of the anatomy, physiologic variations, and pathologic conditions of the fibrous skeleton. The submillimeter isotropic three-dimensional datasets obtained with CT and the high contrast resolution of MR imaging are the main advantages of these modalities in assessing anatomy. The function of the valves and associated annuli can best be studied with MR imaging. Pathologic conditions involving the area, including paravalvar leaks, abscesses, perforation, and pseudoaneurysms, usually occur as a complication of infective endocarditis or extensive calcifications after valvar surgery. MR imaging and CT can demonstrate these lesions equally well. CT is the preferred technique for showing the extent of calcifications in the fibrous skeleton. Large calcifications involving the central fibrous body can cause heart block by interfering with the normal function of the His bundle and its branches. ©RSNA, 2017.

Diaphragm Appearance: A Clue to the Diagnosis of Pulmonary and Extrapulmonary Pathology.

The diaphragm is often overlooked or incompletely evaluated when interpreting chest radiographs. Alterations in the appearance of the diaphragm on chest radiographs such as elevation, contour abnormalities, adjacent lucency, and calcifications can offer clues to pulmonary and extrapulmonary pathology. Familiarity with common causes of these alterations facilitates the appropriate selection of additional imaging and leads to the diagnosis of both benign and life-threatening processes. This article reviews normal variations in the appearance of the diaphragm as well as those associated with pulmonary and extrapulmonary pathology.

Septal Atrioventricular Junction Region: Comprehensive Imaging in Adults.

The septal atrioventricular junction is a centrally located region of the heart where the septal components of the atria and ventricles meet the aortic, mitral, and tricuspid valves. Important structures in this region include the membranous septum, the central fibrous body, the Koch triangle, the inferior pyramidal space, and the base of the interventricular septum. This small area is the home of the atrioventricular node and the atrioventricular conduction axis and has enormous importance to electrophysiologists owing to its prime role in the conduction system of the heart. The atrioventricular node lies within the triangle of Koch; and the atrioventricular bundle, or bundle of His, exits the atrioventricular node and penetrates the right fibrous trigone and runs underneath the membranous septum. The septal atrioventricular junction is a common location for intracardiac shunts such as membranous and perimembranous septal defects. Imaging classification of these defects can have important implications before surgical closure, because the atrioventricular conduction axis passes along the posteroinferior margin of most perimembranous defects. Extracardiac inflammatory and malignant pathologic conditions can extend from the mediastinum toward the inferior pyramidal space in this region through the epicardial fat planes. Although the anatomic structures are complicated, the components can be shown in exquisite detail with computed tomography (CT). In this review, the anatomic boundaries and important anatomic landmarks are examined with CT and magnetic resonance imaging. Also described are the anatomic variants of the membranous septum pertinent to percutaneous aortic valve implantation, the vascular anatomic variants, and commonly encountered pathologic conditions related to the septal atrioventricular junction. ©RSNA, 2016.