Evaluating the Use of ChatGPT to Accurately Simplify Patient-centered Information about Breast Cancer Prevention and Screening.

Purpose To evaluate the use of ChatGPT as a tool to simplify answers to common questions about breast cancer prevention and screening. Materials and Methods In this retrospective, exploratory study, ChatGPT was requested to simplify responses to 25 questions about breast cancer to a sixth-grade reading level in March and August 2023. Simplified responses were evaluated for clinical appropriateness. All original and simplified responses were assessed for reading ease on the Flesch Reading Ease Index and for readability on five scales: Flesch-Kincaid Grade Level, Gunning Fog Index, Coleman-Liau Index, Automated Readability Index, and the Simple Measure of Gobbledygook (ie, SMOG) Index. Mean reading ease, readability, and word count were compared between original and simplified responses using paired t tests. McNemar test was used to compare the proportion of responses with adequate reading ease (score of 60 or greater) and readability (sixth-grade level). Results ChatGPT improved mean reading ease (original responses, 46 vs simplified responses, 70; P < .001) and readability (original, grade 13 vs simplified, grade 8.9; P < .001) and decreased word count (original, 193 vs simplified, 173; P < .001). Ninety-two percent (23 of 25) of simplified responses were considered clinically appropriate. All 25 (100%) simplified responses met criteria for adequate reading ease, compared with only two of 25 original responses (P < .001). Two of the 25 simplified responses (8%) met criteria for adequate readability. Conclusion ChatGPT simplified answers to common breast cancer screening and prevention questions by improving the readability by four grade levels, though the potential to produce incorrect information necessitates physician oversight when using this tool. Keywords: Mammography, Screening, Informatics, Breast, Education, Health Policy and Practice, Oncology, Technology Assessment Supplemental material is available for this article. © RSNA, 2023.

Metastatic Pulmonary Calcification: Single-Center Review of Typical and Atypical Imaging Features.

PURPOSE: The purpose of this study is to bring attention to an atypical form of metastatic pulmonary calcification, which is conventionally described as a metabolic process with upper lobe predominance in patients with a specific clinical history, which has not been reported as a distinct entity. METHODS: Patients with metastatic pulmonary calcification (MPC) were first identified with mPower keyword search, including MPC or metastatic calcifications on computed tomography chest radiological reports. Patients were then filtered on likelihood of MPC based off imaging reports. Images were then reviewed by three senior radiologists for pertinent characteristics such as location of MPC, degree of calcifications and pleural effusions. Based on the predominant location of MPC, cases were labeled as either typical or atypical. Clinical and imaging characteristics relevant to MPC were noted and compared across typical and atypical cases. RESULTS: In our study, we describe 25 patients with MPC, 13 defined as typical MPC and 12 with atypical MPC. Through consensus of senior radiologists, MPC was deemed to be mild (52%), moderate (44%), or severe (4%). Twenty-three patients (92%) had underlying renal disease including 21 requiring dialysis at the time of diagnosis. Outside of age at diagnosis, there was no significant clinical difference between the two groups. Evaluation of imaging characteristics (average HU attenuation, 267; range, 186-295), pattern and distribution of calcification, and clinical history strongly supported a diagnosis of atypical MPC. CONCLUSION: This study presents several cases of lower lobe subpleural MPC associated with pleural effusions, which has not been reported as a distinct entity, despite comprising a significant portion of MPC cases at our institution.

Risk factors and treatment interventions associated with incomplete thrombus resolution and pulmonary hypertension after pulmonary embolism.

BACKGROUND: Residual pulmonary vascular occlusion (RPVO) affects one half of patients after a pulmonary embolism (PE). The relationship between the risk factors and therapeutic interventions for the development of RPVO and chronic thromboembolic pulmonary hypertension is unknown. METHODS: This retrospective review included PE patients within a 26-month period who had baseline and follow-up imaging studies (ie, computed tomography [CT], ventilation/perfusion scans, transthoracic echocardiography) available. We collected the incidence of RPVO, percentage of pulmonary artery occlusion (%PAO), baseline CT %PAO, most recent CT %PAO, and difference between the baseline and most recent %PAO on CT (Δ%PAO). RESULTS: A total of 354 patients had imaging reports available; 197 with CT and 315 with transthoracic echocardiography. The median follow-up time was 144 days (interquartile range [IQR], 102-186 days). RPVO was present in 38.9% of the 354 patients. The median Δ%PAO was -10.0% (IQR, -32% to -1.2%). Fewer patients with a provoked PE developed RPVO (P ≤ .01), and the initial troponin level was lower in patients who developed RPVO (P = .03). The initial thrombus was larger in the patients who received advanced intervention vs anticoagulation (baseline CT %PAO: median, 61.2%; [IQR, 27.5%-75.0%] vs median, 12.5% [IQR, 2.5%-40.0%]; P ≤ .0001). Catheter-directed thrombolysis (CDT; median Δ%PAO, -47.5%; IQR, -63.7% to -8.7%) and surgical pulmonary embolectomy (SPE; median Δ%PAO, -42.5; IQR, -68.1% to -18.7%) had the largest thrombus reduction compared with anticoagulation (P = .01). Of the 354 patients, 76 developed pulmonary hypertension; however, only 14 received pulmonary hypertension medications and 12 underwent pulmonary thromboendarterectomy. Cancer (odds ratio [OR], 1.7) and planned prolonged anticoagulation (>1 year; OR, 2.20) increased the risk of RPVO. In contrast, the risk was lower for men (OR, 0.61), patients with recent surgery (OR, 0.33), and patients treated with SPE (OR, 0.42). A larger Δ%PAO was found in men (coefficient, -8.94), patients with a lower body mass index (coefficient, -0.66), patients treated with CDT (coefficient, -18.12), and patients treated with SPE (coefficient, -21.69). A lower Δ%PAO was found in African-American patients (coefficient, 7.31). CONCLUSIONS: The use of CDT and SPE showed long-term benefit in thrombus reduction.

Lung-Reporting and Data System 2.0: Impact of the Updated Approach to Juxtapleural Nodules During Lung Cancer Screening Using the National Lung Cancer Screening Trial Data Set.

PURPOSE: To determine the frequency of malignancy of nonperifissural juxtapleural nodules (JPNs) measuring 6 to < 10 mm in a subset of low-dose chest computed tomographies from the National Lung Cancer Screening Trial and the rate of down-classification of such nodules in Lung-Reporting and Data System (RADS) 2.0 compared with Lung-RADS 1.1. MATERIALS AND METHODS: A secondary analysis of a subset of the National Lung Screening Trial was performed. An exemption was granted by the Institutional Review Board. The dominant noncalcified nodule measuring 6 to <10 mm was identified on all available prevalence computed tomographies. Nodules were categorized as pleural or nonpleural. Benign or malignant morphology was recorded. Initial and updated categories based on Lung-RADS 1.1 and Lung-RADS 2.0 were assigned, respectively. The impact of the down-classification of JPN was assessed. Both classification schemes were compared using the McNemar test (P < 0.01). RESULTS: A total of 2813 patients (62 ± 5 y, 1717 men) with 4408 noncalcified nodules were studied. One thousand seventy-three dominant nodules measuring 6 to <10 mm were identified. Three hundred forty-eight (32.4%) were JPN. The updated scheme allowed down-classification of 310 JPN from categories 3 (n = 198) and 4A (n = 112) to category 2. We, therefore, estimate a 4.8% rate of down-classification to category 2 in the entire National Lung Screening Trial screening group. Two/348 (0.57%) JPN were malignant, both nonbenign in morphology. The false-positive rate decreased in the updated classification (P < 0.01). CONCLUSION: This study demonstrates the low malignant potential of benign morphology JPN measuring 6 mm to <10 mm. The Lung-RADS 2.0 approach to JPN is estimated to reduce short-term follow-ups and false-positive results.

Use of ChatGPT, GPT-4, and Bard to Improve Readability of ChatGPT's Answers to Common Questions About Lung Cancer and Lung Cancer Screening.

ChatGPT's responses to questions about lung cancer and LCS, although deemed clinically appropriate by cardiothoracic radiologists, were difficult to read. Simplified responses from three LLMs (ChatGPT, GPT-4, and Bard) had improved reading ease and readability (in terms of U.S. grade levels). However, some simplified responses were no longer clinically appropriate.

A pilot study of deep learning-based CT volumetry for traumatic hemothorax.

PURPOSE: We employ nnU-Net, a state-of-the-art self-configuring deep learning-based semantic segmentation method for quantitative visualization of hemothorax (HTX) in trauma patients, and assess performance using a combination of overlap and volume-based metrics. The accuracy of hemothorax volumes for predicting a composite of hemorrhage-related outcomes - massive transfusion (MT) and in-hospital mortality (IHM) not related to traumatic brain injury - is assessed and compared to subjective expert consensus grading by an experienced chest and emergency radiologist. MATERIALS AND METHODS: The study included manually labeled admission chest CTs from 77 consecutive adult patients with non-negligible (≥ 50 mL) traumatic HTX between 2016 and 2018 from one trauma center. DL results of ensembled nnU-Net were determined from fivefold cross-validation and compared to individual 2D, 3D, and cascaded 3D nnU-Net results using the Dice similarity coefficient (DSC) and volume similarity index. Pearson's r, intraclass correlation coefficient (ICC), and mean bias were also determined for the best performing model. Manual and automated hemothorax volumes and subjective hemothorax volume grades were analyzed as predictors of MT and IHM using AUC comparison. Volume cut-offs yielding sensitivity or specificity ≥ 90% were determined from ROC analysis. RESULTS: Ensembled nnU-Net achieved a mean DSC of 0.75 (SD: ± 0.12), and mean volume similarity of 0.91 (SD: ± 0.10), Pearson r of 0.93, and ICC of 0.92. Mean overmeasurement bias was only 1.7 mL despite a range of manual HTX volumes from 35 to 1503 mL (median: 178 mL). AUC of automated volumes for the composite outcome was 0.74 (95%CI: 0.58-0.91), compared to 0.76 (95%CI: 0.58-0.93) for manual volumes, and 0.76 (95%CI: 0.62-0.90) for consensus expert grading (p = 0.93). Automated volume cut-offs of 77 mL and 334 mL predicted the outcome with 93% sensitivity and 90% specificity respectively. CONCLUSION: Automated HTX volumetry had high method validity, yielded interpretable visual results, and had similar performance for the hemorrhage-related outcomes assessed compared to manual volumes and expert consensus grading. The results suggest promising avenues for automated HTX volumetry in research and clinical care.

Early pulmonary complications related to cancer treatment in children.

In this review, we summarize early pulmonary complications related to cancer therapy in children and highlight characteristic findings on imaging that should be familiar to a radiologist reviewing imaging from pediatric cancer patients.

Prevalence of Clinical and Subclinical Myocarditis in Competitive Athletes With Recent SARS-CoV-2 Infection: Results From the Big Ten COVID-19 Cardiac Registry.

Importance: Myocarditis is a leading cause of sudden death in competitive athletes. Myocardial inflammation is known to occur with SARS-CoV-2. Different screening approaches for detection of myocarditis have been reported. The Big Ten Conference requires comprehensive cardiac testing including cardiac magnetic resonance (CMR) imaging for all athletes with COVID-19, allowing comparison of screening approaches. Objective: To determine the prevalence of myocarditis in athletes with COVID-19 and compare screening strategies for safe return to play. Design, Setting, and Participants: Big Ten COVID-19 Cardiac Registry principal investigators were surveyed for aggregate observational data from March 1, 2020, through December 15, 2020, on athletes with COVID-19. For athletes with myocarditis, presence of cardiac symptoms and details of cardiac testing were recorded. Myocarditis was categorized as clinical or subclinical based on the presence of cardiac symptoms and CMR findings. Subclinical myocarditis classified as probable or possible myocarditis based on other testing abnormalities. Myocarditis prevalence across universities was determined. The utility of different screening strategies was evaluated. Exposures: SARS-CoV-2 by polymerase chain reaction testing. Main Outcome and Measure: Myocarditis via cardiovascular diagnostic testing. Results: Representing 13 universities, cardiovascular testing was performed in 1597 athletes (964 men [60.4%]). Thirty-seven (including 27 men) were diagnosed with COVID-19 myocarditis (overall 2.3%; range per program, 0%-7.6%); 9 had clinical myocarditis and 28 had subclinical myocarditis. If cardiac testing was based on cardiac symptoms alone, only 5 athletes would have been detected (detected prevalence, 0.31%). Cardiac magnetic resonance imaging for all athletes yielded a 7.4-fold increase in detection of myocarditis (clinical and subclinical). Follow-up CMR imaging performed in 27 (73.0%) demonstrated resolution of T2 elevation in all (100%) and late gadolinium enhancement in 11 (40.7%). Conclusions and Relevance: In this cohort study of 1597 US competitive athletes with CMR screening after COVID-19 infection, 37 athletes (2.3%) were diagnosed with clinical and subclinical myocarditis. Variability was observed in prevalence across universities, and testing protocols were closely tied to the detection of myocarditis. Variable ascertainment and unknown implications of CMR findings underscore the need for standardized timing and interpretation of cardiac testing. These unique CMR imaging data provide a more complete understanding of the prevalence of clinical and subclinical myocarditis in college athletes after COVID-19 infection. The role of CMR in routine screening for athletes safe return to play should be explored further.

Lung-RADS Version 1.0 versus Lung-RADS Version 1.1: Comparison of Categories Using Nodules from the National Lung Screening Trial.

Background The American College of Radiology updated Lung Imaging Reporting and Data System (Lung-RADS) version 1.0 to version 1.1 in May 2019, with the two key changes involving perifissural nodules (PFNs) and ground-glass nodules (GGNs) now designated as a negative screening result. This study examines the effects of these changes using National Lung Screening Trial (NLST) data. Purpose To determine the frequency of PFNs and GGNs reclassified from category 3 or 4A to the more benign category 2 in the updated Lung-RADS version 1.1, as compared with Lung-RADS version 1.0, using CT scans from the NLST. Materials and Methods In this secondary analysis of the NLST, the authors studied all noncalcified nodules (NCNs) found on the incident scan. Nodules were evaluated using criteria from both Lung-RADS version 1.0 and version 1.1, which were compared to determine changes in the number of nodules deemed benign. A McNemar test was used to assess statistical significance. Results A total of 2813 patients (mean age ± standard deviation, 62 years ± 5; 1717 men) with 4408 NCNs were studied. Of the largest 1092 solid NCNs measuring at least 6 mm but less than 10 mm, 216 (19.8%) were deemed PFNs (category 2) using Lung-RADS version 1.1. Eleven of the 1092 solid NCNs (1.0%) were malignant, but none were PFNs. Of 161 GGNs, three (1.9%) were category 3 according to Lung-RADS version 1.0, of which two (66.7%) were down-classified to category 2 with version 1.1. One of the three down-categorized GGNs (version 1.1) proved to be malignant (false-negative finding). Statistically significant improvement for Lung-RADS version 1.1 was found for total nodules (P < .01) and PFNs (P < .01), but not GGNs (P = .48). Conclusion This secondary analysis of National Lung Screening Trial data shows that Lung Imaging Reporting and Data System version 1.1 decreased the number of false-positive results. This was related to the down-classification of perifissural nodules in the range of 6 up to 10 mm. The increase in allowable nodule size for ground-glass nodules in category 2 from 20 mm (version 1.0) to 30 mm (version 1.1) showed no benefit. © RSNA, 2021 See also the editorial by Mayo and Lam in this issue.

Endovascular Repair of Ascending Aortic Disease in High-Risk Patients Yields Favorable Outcome.

BACKGROUND: Up to 30% of patients presenting with ascending aortic disease are deemed inoperable. Ascending aortic endovascular repair provides an alternative option for these patients. METHODS: From 2018 to 2019, 13 patients who were considered to have prohibitive risk for open ascending aortic repair underwent endovascular repair. Aortic disease included type A dissection (n = 8), pseudoaneurysm (n = 3), penetrating ulcer (n = 3), and chronic aortic aneurysm (n = 1). Ascending aortic stent placement with thoracic endovascular aortic repair was performed in 9 patients, endovascular cuff extension was inserted in 3, and in 1 patient endovascular coil embolization was undertaken. Preoperative and follow-up electrocardiogram-gated computed tomographic analysis was performed to compare the remodeling effect of the stent on the aorta. The median follow-up time was 13 months. RESULTS: The stent graft was successfully implanted in all patients (100%). Operative mortality and stroke rate were 15% (2 of 13) and 8% (1 of 13), respectively. One patient required transcatheter aortic valve replacement for severe aortic insufficiency 5 months after ascending thoracic endovascular aortic repair. The location of the aortic pathologic process was in zone 0A in 2 patients, zone 0B in 7 patients, and zone 0C in 3 patients. No endoleak was observed after the ascending endovascular repair in 9 patients (70%). Follow-up computed tomographic scan analysis revealed a tendency of favorable aortic remodeling in the mid-ascending and descending aorta. CONCLUSIONS: Ascending aortic stent placement for ascending aortic disease is feasible and is associated with favorable aortic remodeling. Despite persistent perfusion to the false lumen in a subset of patients, there is minimal aortic dilation at short-term follow-up with excellent survival.

Predictors of Recovery in Patients Supported With Venoarterial Extracorporeal Membrane Oxygenation for Acute Massive Pulmonary Embolism.

BACKGROUND: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has emerged as a promising initial support strategy for acute massive pulmonary embolism. However, it remains unclear which patients will ultimately require surgical pulmonary embolectomy (SPE) vs anticoagulation alone. METHODS: All consecutive patients (2015-2018) with confirmed massive PE, placed on VA-ECMO utilizing a protocolized approach, were reviewed. Per protocol, patients were supported for 3 to 5 days before reevaluation of right ventricular (RV) function via echocardiography. If RV function recovered, VA-ECMO was discontinued with no further intervention (no-SPE group). In patients with persistent RV dysfunction, SPE was performed. RESULTS: Forty-five patients were identified, and 41 patients were treated per protocol. Seventy-three percent responded to anticoagulation alone, and 27% required SPE. Factors associated with SPE rather than decannulation with anticoagulation alone included prolonged shortness of breath, elevated N-terminal prohormone of brain natriuretic peptide, enlarged pulmonary artery diameter, and history of venous thromboembolism. A predictive algorithm was developed with a negative predictive value of 97% and a specificity of 97% for a low-risk score, and a positive predictive value of 100% and sensitivity of 67% for a high-risk score. Overall, 90-day survival was 97% in the no-SPE group and 100% in the SPE group. CONCLUSIONS: In this cohort, greater than 70% of patients who presented with massive PE and supported with VA-ECMO ultimately recovered with anticoagulation alone. Specific risk factors, likely related to thrombus chronicity, may be associated with lack of RV recovery, and can be utilized for consideration of early surgical intervention to minimize VA-ECMO duration.

Bronchial artery laceration and haemothorax complicating transbronchial needle aspiration.

A 74-year-old woman presented with chest pain and dyspnoea following endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA) for presumed malignancy. Computed tomography angiography revealed a left-sided pleural effusion with hypertrophied and tortuous bronchial arteries (BAs) with contrast blush into the left lung hilum. Tube thoracostomy and pleural fluid analysis confirmed the diagnosis of haemothorax. The mechanism of injury was determined to be BA laceration during EBUS-TBNA and drainage led to rapid improvement in the patient's symptoms. This is the first reported case of haemothorax due to BA injury during EBUS-TBNA.

Assessment of Myocarditis: Cardiac MR, PET/CT, or PET/MR?

PURPOSE OF REVIEW: Diagnosis of myocarditis is challenging given its variable clinical manifestations and non-specific laboratory findings. Cardiac magnetic resonance (MR) is currently the preferred imaging modality for the diagnosis of myocarditis. 18F-fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT), as a functional imaging tool, has a potential role in the assessment of myocarditis by detecting the underlying myocardial inflammatory activity. Data are accumulating that simultaneous cardiac PET/MR may have complementary and incremental values for the evaluation of myocarditis compared to PET/CT or cardiac MR alone. The article aims to summarize the findings in the literature and discuss future directions of cardiac PET/MR for myocarditis. RECENT FINDINGS: The Lake Louis Criteria (CLL) of cardiac MR is widely used for the diagnosis of myocarditis. It has an overall acceptable sensitivity of 67% and specificity of 91% for acute myocarditis but does not have the same accuracy for chronic myocarditis. FDG PET/CT is capable of assessing myocarditis by providing metabolic information of inflammation as increased myocardial FDG uptake. In addition to reduced radiation exposure, FDG PET performed on a hybrid PET/MR may detect more myocarditis than FDG PET/CT, because of the delayed PET acquisition time on PET/MR. Case-based observations and small clinical studies of FDG PET/MR have shown that FDG PET findings as abnormally increased myocardial uptake correlate well with the cardiac MR biomarkers. FDG PET findings may add complementary and incremental values to cardiac MR by improving the sensitivity of cardiac MR for mild or borderline myocarditis, and increasing specificity for chronic myocarditis. Preliminary data from retrospective and case-based observational studies have suggested the complementary and incremental values of simultaneous cardiac FDG PET/MR for evaluation of myocarditis, compared to PET/CT or MR alone. Well-designed studies are needed to confirm the findings and to assess the value of cardiac PET/MR for clinical management and more importantly patient's outcome in both acute and chronic myocarditis.

Occult Chronic Thromboembolic Disease in Patients Presenting for Surgical Pulmonary Embolectomy.

BACKGROUND: Pulmonary embolism is a significant cause of morbidity and mortality. An important subpopulation of patients presenting with acute pulmonary embolism have concurrent undiagnosed chronic thromboembolic disease. We sought to further characterize this subpopulation, specifically in a cohort of patients referred for surgical pulmonary embolectomy. METHODS: A retrospective review of all patients requiring surgical pulmonary embolectomy at a single center (2013-2017) was performed. Chart review and blinded examination of presenting computed tomographic pulmonary angiograms were done to identify clinical and radiographic features associated with acute on chronic disease. A predictive tool utilizing readily accessible variables was then constructed for risk stratification. RESULTS: A total of 90 patients were identified for analysis; 34 were treated by specifically trained pulmonary thromboendarterectomy surgeons. Twelve patients in the subgroup treated by pulmonary thromboendarterectomy surgeons were found to have acute on chronic disease confirmed by intraoperative endarterectomized specimen. On univariate analysis, degree of pulmonary artery and inferior vena cava dilation and duration of respiratory symptoms were statistically significant variables. Severe right ventricular hypertrophy, elevation in N-terminal pro-B-type natriuretic peptide, and unprovoked etiology were also associated with acute on chronic disease. A predictive tool weighing the presence of these features was created allowing for stratification into low-, moderate-, and high-risk patients. The positive predictive value of a high-risk score was 100%. CONCLUSIONS: In this cohort, the prevalence of acute on chronic thromboembolic disease was greater than 1 in 3. Readily available clinical and radiographic features were used to create a predictive tool for risk stratification.

Peripheral Distribution of Thrombus Does Not Affect Outcomes After Surgical Pulmonary Embolectomy.

BACKGROUND: Thrombus located distal to the main or primary pulmonary arteries has been previously viewed as a relative contraindication to surgical pulmonary embolectomy. We compared outcomes for surgical pulmonary embolectomy for submassive and massive pulmonary embolism (PE) in patients with central vs peripheral thrombus burden. METHODS: All consecutive patients (2011 to 2016) undergoing surgical pulmonary embolectomy at a single center were retrospectively reviewed. Computed tomography angiography of each patient was used to define central PE as any thrombus originating within the lateral pericardial borders (main or right/left pulmonary arteries). Peripheral PE was defined as thrombus exclusively beyond the lateral pericardial borders, involving the lobar pulmonary arteries or distal. The primary outcome was in-hospital and 90-day survival. RESULTS: We identified 70 patients: 52 (74%) with central PE and 18 (26%) with peripheral PE. Preoperative vital signs and right ventricular dysfunction were similar between the two groups. Compared with the central PE cohort, operative time was significantly longer in the peripheral PE group (191 vs 210 minutes, p < 0.005). Median right ventricular dysfunction decreased from moderate dysfunction preoperatively to no dysfunction at discharge in both groups. Overall 90-day survival was 94%, with 100% survival in patients with submassive PE in both cohorts. CONCLUSIONS: This single-center experience demonstrates excellent overall outcomes for surgical pulmonary embolectomy, with resolution of right ventricular dysfunction and comparable morbidity and mortality for central and peripheral PE. In an experienced center and when physiologically warranted, surgical pulmonary embolectomy for peripheral distribution of thrombus is technically feasible and effective.

Validation of a novel CARTOSEG™ segmentation module software for contrast-enhanced computed tomography-guided radiofrequency ablation in patients with atrial fibrillation.

INTRODUCTION: Visualization of left atrial (LA) anatomy using image integration modules has been associated with decreased radiation exposure and improved procedural outcome when used for guidance of pulmonary vein isolation (PVI) in atrial fibrillation (AF) ablation. We evaluated the CARTOSEG™ CT Segmentation Module (Biosense Webster, Inc.) that offers a new CT-specific semiautomatic reconstruction of the atrial endocardium. METHODS: The CARTOSEG™ CT Segmentation Module software was assessed prospectively in 80 patients undergoing AF ablation. Using preprocedural contrast-enhanced computed tomography (CE-CT), cardiac chambers, coronary sinus (CS), and esophagus were semiautomatically segmented. Segmentation quality was assessed from 1 (poor) to 4 (excellent). The reconstructed structures were registered with the electroanatomic map (EAM). PVI was performed using the registered 3D images. RESULTS: Semiautomatic reconstruction of the heart chambers was successfully performed in all 80 patients with AF. CE-CT DICOM file import, semiautomatic segmentation of cardiac chambers, esophagus, and CS was performed in 185 ± 105, 18 ± 5, 119 ± 47, and 69 ± 19 seconds, respectively. Average segmentation quality was 3.9 ± 0.2, 3.8 ± 0.3, and 3.8 ± 0.2 for LA, esophagus, and CS, respectively. Registration accuracy between the EAM and CE-CT-derived segmentation was 4.2 ± 0.9 mm. Complications consisted of one perforation (1%) which required pericardiocentesis, one increased pericardial effusion treated conservatively (1%), and one early termination of ablation due to thrombus formation on the ablation sheath without TIA/stroke (1%). All targeted PVs (n  =  309) were successfully isolated. CONCLUSIONS: The novel CT- CARTOSEG™ CT Segmentation Module enables a rapid and reliable semiautomatic 3D reconstruction of cardiac chambers and adjacent anatomy, which facilitates successful and safe PVI.