Strategies for Reducing False-Positive Screening Results for Intermediate-Size Nodules Evaluated Using Lung-RADS: A Secondary Analysis of National Lung Screening Trial Data.

BACKGROUND. Lung-RADS version 1.1 (v1.1) classifies all solid nodules less than 6 mm as category 2. Lung-RADS v1.1 also classifies solid intermediate-size (6 to < 10 mm) nodules as category 2 if they are perifissural and have a triangular, polygonal, or ovoid shape (indicative of intrapulmonary lymph nodes). Additional category 2 criteria could reduce false-positive results of screening examinations. OBJECTIVE. The purpose of this study was to evaluate the impact of proposed strategies for reducing false-positive results for intermediate-size nodules on lung cancer screening CT evaluated using Lung-RADS v1.1. METHODS. This retrospective study entailed secondary analysis of National Lung Screening Trial (NLST) data. Of 1387 solid nodules measuring 6.0-9.5 mm on baseline screening CT examinations in the NLST, all 38 nodules in patients who developed cancer and a random sample of 200 nodules in patients who did not develop cancer were selected for further evaluation. Cancers were required to correspond with the baseline nodule on manual review. After exclusions, the sample included 223 patients (median age, 62 years; 143 men, 80 women; 196 benign nodules, 27 malignant nodules). Two thoracic radiologists independently reviewed baseline examinations to record nodule diameter and volume using semiautomated software and to determine whether nodules had perifissural location; other subpleural location; and triangular, polygonal, or ovoid shape. Different schemes for category 2 assignment were compared. RESULTS. Across readers, standard Lung-RADS v1.1 had sensitivity of 89-93% and specificity of 26-31%. A modification assigning nodules less than 10 mm with triangular, polygonal, or ovoid shape in other subpleural locations (vs only perifissural location) as category 2 had sensitivity of 85-93% and specificity of 47-51%. Lung-RADS v1.1 using volume cutoffs had sensitivity of 89-93% and specificity of 37% (both readers). The sensitivity of both modified Lung-RADS v1.1 and Lung-RADS v1.1 with volume cutoffs was not significantly different from standard Lung-RADS v1.1 (all p > .05). However, both schemes' specificity was significantly better than standard Lung-RADS v1.1 (all p < .05). Combining the two strategies yielded sensitivity of 85-93% and specificity of 58-59%. CONCLUSION. Classifying intermediate-size nodules with triangular, polygonal, or ovoid shape in any subpleural (not just perifissural) location as category 2 and using volume- rather than diameter-based measurements improves Lung-RADS specificity without decreased sensitivity. CLINICAL IMPACT. The findings can help reduce false-positive results, decreasing 6-month follow-up examinations for benign findings.

Radiologic-Pathologic Correlation for Nondiagnostic CT-Guided Lung Biopsies Performed for the Evaluation of Lung Cancer.

OBJECTIVE. For nondiagnostic CT-guided lung biopsies, we tested whether radiologicpathologic correlation could identify patients who may benefit from repeat biopsy. MATERIALS AND METHODS. In this retrospective study, 1525 lung biopsies were performed between July 2013 and June 2017, 243 of which were nondiagnostic. Of these 243 lung biopsies, 98 were performed to evaluate for lung malignancy; 17 were excluded because of insufficient follow-up, leaving a total of 81 cases. The Brock and Herder models were used to calculate risk; in addition, cases were independently blindly reviewed by two thoracic radiologists who assigned a score from 1 (probably benign) to 5 (probably malignant). The final diagnosis was established by pathology results or benignancy was established if the lesion resolved or remained stable for at least 2 years. RESULTS. Of the 81 nondiagnostic lung biopsies, initial pathology results included 33 cases of inflammation, 28 cases of normal lung tissue or insufficient sample, 10 cases of organizing pneumonia, and 10 cases of atypical cells. 42% (34/81) of cases were eventually determined to be malignant (negative predictive value [NPV] of 58%). Pathology results of organizing pneumonia had the lowest rate of malignancy (2/10 = 20%), and pathology results of atypical cells had the highest rate of malignancy (5/10 = 50%, p = 0.51). Within this highly selected cohort, the Brock and Herder models were not predictive of malignancy, with areas under the ROC curve (AUCs) of 0.52 and 0.52, respectively. Evaluation by thoracic radiologists yielded AUCs of 0.85 and 0.77. When radiologist-assigned scores of 1 and 2 were considered as benign, the NPV was 90% and 95%. CONCLUSION. Review of nondiagnostic lung biopsies for radiologic-pathologic concordance by thoracic radiologists can triage patients who may benefit from repeat biopsy.

Cancer Risk in Subsolid Nodules in the National Lung Screening Trial.

Background Subsolid pulmonary nodules, comprising pure ground-glass nodules (GGNs) and part-solid nodules (PSNs), have a high risk of indolent malignancy. Lung Imaging Reporting and Data System (Lung-RADS) nodule management guidelines are based on expert opinion and lack independent validation. Purpose To evaluate Lung-RADS estimates of the malignancy rates of subsolid nodules, using nodules from the National Lung Screening Trial (NLST), and to compare Lung-RADS to the NELSON trial classification as well as the Brock University calculator. Materials and Methods Subsets of GGNs and PSNs were selected from the NLST for this retrospective study. A thoracic radiologist reviewed the baseline and follow-up CT images, confirmed that they were true subsolid nodules, and measured the nodules. The primary outcome for each nodule was the development of malignancy within the follow-up period (median, 6.5 years). Nodules were stratified according to Lung-RADS, NELSON trial criteria, and the Brock model. For analyses, nodule subsets were weighted on the basis of frequency in the NLST data set. Nodule stratification models were tested by using receiver operating characteristic curves. Results A total of 622 nodules were evaluated, of which 434 nodules were subsolid. At baseline, 304 nodules were classified as Lung-RADS category 2, with a malignancy rate of 3%, which is greater than the 1% in Lung-RADS (P = .004). The malignancy rate for GGNs smaller than 10 mm (two of 129, 1.3%) was smaller than that for GGNs measuring 10-19 mm (11 of 153, 6%) (P = .01). The malignancy rate for Lung-RADS category 3 was 14% (13 of 67), which is greater than the reported 2% in Lung-RADS (P < .001). The Brock model predicted malignancy better than Lung-RADS and the NELSON trial scheme (area under the receiver operating characteristic curve = 0.78, 0.70, and 0.67, respectively; P = .02 for Brock model vs NELSON trial scheme). Conclusion Subsolid nodules classified as Lung Imaging Reporting and Data System (Lung-RADS) categories 2 and 3 have a higher risk of malignancy than reported. The Brock risk calculator performed better than measurement-based classification schemes such as Lung-RADS. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Kauczor and von Stackelberg in this issue.

Predictive Features for Anterior Mediastinal Mass Diagnoses.

OBJECTIVE: We set out to evaluate a set of demographic and computed tomography imaging features for diagnosing anterior mediastinal masses. METHODS: We identified 223 patients with anterior mediastinal masses, which we divided into training and validation sets. One radiologist evaluated computed tomography imaging features on the training set. Then, predictive features were identified, and 3 radiologists evaluated these on the validation set. A naive Bayesian classifier based on the features was compared with the radiologists' first-choice diagnosis. RESULTS: Internal mammary lymphadenopathy and mediastinal encasement were strongly associated with lymphomas. Low attenuation and midline location were strongly associated with benign lesions, and older age was associated with thymic epithelial neoplasms. The average accuracy of the 3 radiologists' diagnoses was 78%, compared with 71% for the classifier. CONCLUSIONS: Nine demographic and imaging features were found to be helpful in diagnosing anterior mediastinal masses. By using these features, radiologists can suggest the diagnosis with fair accuracy.

Utility and reproducibility of 3-dimensional printed models in pre-operative planning of complex thoracic tumors.

BACKGROUND AND OBJECTIVES: 3D-printed models are increasingly used for surgical planning. We assessed the utility, accuracy, and reproducibility of 3D printing to assist visualization of complex thoracic tumors for surgical planning. METHODS: Models were created from pre-operative images for three patients using a standard radiology 3D workstation. Operating surgeons assessed model utility using the Gillespie scale (1 = inferior to 4 = superior), and accuracy compared to intraoperative findings. Model variability was assessed for one patient for whom two models were created independently. The models were compared subjectively by surgeons and quantitatively based on overlap of depicted tissues, and differences in tumor volume and proximity to tissues. RESULTS: Models were superior to imaging and 3D visualization for surgical planning (mean score = 3.4), particularly for determining surgical approach (score = 4) and resectability (score = 3.7). Model accuracy was good to excellent. In the two models created for one patient, tissue volumes overlapped by >86.5%, and tumor volume and area of tissues ≤1 mm to the tumor differed by <15% and <1.8 cm2 , respectively. Surgeons considered these differences to have negligible effect on surgical planning. CONCLUSION: 3D printing assists surgical planning for complex thoracic tumors. Models can be created by radiologists using routine practice tools with sufficient accuracy and clinically negligible variability.

Frequency and Severity of Pulmonary Hemorrhage in Patients Undergoing Percutaneous CT-guided Transthoracic Lung Biopsy: Single-Institution Experience of 1175 Cases.

PURPOSE: To evaluate the frequency and severity of pulmonary hemorrhage after transthoracic needle lung biopsy (TTLB) and assess possible factors associated with pulmonary hemorrhage. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. Records from 1113 patients who underwent 1175 TTLBs between January 2008 and April 2013 were retrospectively reviewed. Primary outcomes were pulmonary hemorrhage, documented hemoptysis, and bleeding complications necessitating intervention. Pulmonary hemorrhage was graded as follows: 0, none; 1, less than or equal to 2 cm around the needle; 2, more than 2 cm and sublobar; 3, at least lobar; and 4, hemothorax. Patient, technique, and lesion-related variables were evaluated as predictors of pulmonary hemorrhage. Patient-related variables included main pulmonary artery diameter (mPAD) at computed tomography (CT), pulmonary artery pressures at echocardiography and right-sided heart catheterization, medications, chronic lung disease, bleeding diathesis, and immunodeficiency. Technique- and lesion-related variables included needle gauge, number of passes, pleura-needle angle, lesion size and morphologic characteristics, and distance to pleura. Univariate analysis was performed with χ(2), Fisher exact, and Student t tests. RESULTS: Pulmonary hemorrhage occurred in 483 of the 1175 TTLBs (41.1%); hemoptysis was documented in 21 of the 1175 TTLBs (1.8%). Higher-grade hemorrhage (grade 2 or higher) occurred in 201 of the 1175 TTLBs (17.1%); five of the 1175 TTLBs (0.4%) necessitated hemorrhage-related admission. Higher-grade hemorrhage was more likely to occur with female sex (P = .001), older age (P = .003), emphysema (P = .004), coaxial technique (P = .025), nonsubpleural location (P < .001), lesion size of 3 cm or smaller (P < .001), and subsolid lesions (P = .028). Enlarged mPAD at CT (≥2.95 cm) was not significantly associated with higher-grade hemorrhage (P = .430). CONCLUSION: Pulmonary hemorrhage after TTLB is common but rarely requires intervention. An enlarged mPAD at CT may not be a risk factor for higher-grade hemorrhage.

Effect of Evidence-based Clinical Decision Support on the Use and Yield of CT Pulmonary Angiographic Imaging in Hospitalized Patients.

PURPOSE: To determine the effect of clinical decision support (CDS) on the use and yield of inpatient computed tomographic (CT) pulmonary angiography for acute pulmonary embolism (PE). MATERIALS AND METHODS: This HIPAA-compliant, institutional review board-approved study with waiver of informed consent included all adults admitted to a 793-bed teaching hospital from April 1, 2007, to June 30, 2012. The CDS intervention, implemented after a baseline observation period, informed providers who placed an order for CT pulmonary angiographic imaging about the pretest probability of the study based on a validated decision rule. Use of CT pulmonary angiographic and admission data from administrative databases was obtained for this study. By using a validated natural language processing algorithm on radiology reports, each CT pulmonary angiographic examination was classified as positive or negative for acute PE. Primary outcome measure was monthly use of CT pulmonary angiography per 1000 admissions. Secondary outcome was CT pulmonary angiography yield (percentage of CT pulmonary angiographic examinations that were positive for acute PE). Linear trend analysis was used to assess for effect and trend differences in use and yield of CT pulmonary angiographic imaging before and after CDS. RESULTS: In 272 374 admissions over the study period, 5287 patients underwent 5892 CT pulmonary angiographic examinations. A 12.3% decrease in monthly use of CT pulmonary angiography (26.0 to 22.8 CT pulmonary angiographic examinations per 1000 admissions before and after CDS, respectively; P = .008) observed 1 month after CDS implementation was sustained over the ensuing 32-month period. There was a nonsignificant 16.3% increase in monthly yield of CT pulmonary angiography or percentage of CT pulmonary angiographic examinations positive for acute PE after CDS (P = .65). CONCLUSION: Implementation of evidence-based CDS for inpatients was associated with a 12.3% immediate and sustained decrease in use of CT pulmonary angiographic examinations in the evaluation of inpatients for acute PE. for this article.

Classification of CT pulmonary angiography reports by presence, chronicity, and location of pulmonary embolism with natural language processing.

In this paper we describe an efficient tool based on natural language processing for classifying the detail state of pulmonary embolism (PE) recorded in CT pulmonary angiography reports. The classification tasks include: PE present vs. absent, acute PE vs. others, central PE vs. others, and subsegmental PE vs. others. Statistical learning algorithms were trained with features extracted using the NLP tool and gold standard labels obtained via chart review from two radiologists. The areas under the receiver operating characteristic curves (AUC) for the four tasks were 0.998, 0.945, 0.987, and 0.986, respectively. We compared our classifiers with bag-of-words Naive Bayes classifiers, a standard text mining technology, which gave AUC 0.942, 0.765, 0.766, and 0.712, respectively.

Risk of Lung Cancer in Peripheral Pulmonary Nodules.

PURPOSE: To determine the risk of lung cancer and inter-observer agreement for small pulmonary nodules either touching or near the pleura. METHODS: Nodules were derived from two cohorts: patients from the National Lung Screening Trial with a solid nodule measuring 6-9.5 mm; and patients with incidental pulmonary nodules in our healthcare system with a solid nodule measuring 1-8 mm. Only the dominant nodule was evaluated for each patient. All malignant nodules as well as a random sample of 200 benign nodules from each cohort were included. Two fellowship-trained thoracic radiologists independently reviewed each case to record nodule morphology (compatible with lymph node or not) and nodule location (pleural-based, septal connection to the pleura, or neither). One radiologist measured the distance to the pleura. RESULTS: After exclusion criteria were applied, a total of 434 nodules were included, of which 45 were lung cancers. Considering all pleural-based nodules with lymph node morphology as benign, 0-7% of cancers were misclassified as benign, specificity 33%, and κ = 0.69. Considering subpleural nodules and those with septal connection to the pleura, 7-11% of cancers were misclassified (p = 0.16-0.25 versus pleural-based), specificity 40-52% (p < .0001), and κ = 0.60. Considering nodules with lymph node morphology ≤ 2 mm from the pleura, 2-7% of cancers were misclassified (p = 1 versus pleural-based), specificity 41-36% (p < .0001), and κ = 0.78. CONCLUSION: Considering nodules with lymph node morphology with septal connection, or those ≤ 2 mm from the pleura, as benign does not lead to significant misclassification of lung cancers as benign.

ACR Lung-RADS v2022: Assessment Categories and Management Recommendations.

The ACR created the Lung CT Screening Reporting and Data System (Lung-RADS) in 2014 to standardize the reporting and management of screen-detected pulmonary nodules. Lung-RADS was updated to version 1.1 in 2019 and revised size thresholds for nonsolid nodules, added classification criteria for perifissural nodules, and allowed for short-interval follow-up of rapidly enlarging nodules that may be infectious in etiology. Lung-RADS v2022, released in November 2022, provides several updates including guidance on the classification and management of atypical pulmonary cysts, juxtapleural nodules, airway-centered nodules, and potentially infectious findings. This new release also provides clarification for determining nodule growth and introduces stepped management for nodules that are stable or decreasing in size. This article summarizes the current evidence and expert consensus supporting Lung-RADS v2022.

CT Pulmonary Angiogram Clinical Pretest Probability Tool: Impact on Emergency Department Utilization.

OBJECTIVE: Currently, computed tomographic pulmonary angiogram (CTPA) for evaluating acute pulmonary embolism (PE) in Emergency Departments (EDs) is overused and with low yields. The goal of this study is to assess the impact of an evidence-based clinical decision support (CDS) tool, aimed at optimizing appropriate use of CTPA for evaluating PE. METHODS: The study was performed at EDs in a large healthcare system and included 9 academic and community hospitals. The primary outcome was the percent difference in utilization (number of CTPA performed/number of ED visits) and secondary outcome was yield (percentage of CTPA positive for acute PE), comparing 12 months before (6/1/2021-5/31/2022) vs. 12 months after (6/1/2022-5/31/2023) a system-wide implementation of the CDS. Univariate and multivariable analyses using logistic regression were performed to assess factors associated with diagnosis of acute PE. Statistical process control (SPC) charts were used to assess monthly trends in utilization and yield. RESULTS: Among 931,677 visits to Emergency Departments, 28,101 CTPAs were performed on 24,675 patients. 14,825 CTPAs were performed among 455,038 visits (3.26%) pre-intervention; 13,276 among 476,639 visits (2.79%) post-intervention, a 14.51% relative decrease in CTPA utilization (chi-square, p<0.001). CTPA yield remained unchanged (1371/14825=9.25% pre- vs. 1184/13276=8.92% post-intervention; chi-square, p=0.34). Patients with COVID diagnosis prior to CTPA had higher probability of acute PE. SPC charts demonstrated seasonal variation in utilization (Friedman test, p=0.047). DISCUSSION: Implementing a CDS based on validated decision rules was associated with a significant reduction in CTPA utilization. The change was immediate and sustained for 12 months post-intervention.

ACR Lung-RADS v2022: Assessment Categories and Management Recommendations.

The American College of Radiology created the Lung CT Screening Reporting and Data System (Lung-RADS) in 2014 to standardize the reporting and management of screen-detected pulmonary nodules. Lung-RADS was updated to version 1.1 in 2019 and revised size thresholds for nonsolid nodules, added classification criteria for perifissural nodules, and allowed for short-interval follow-up of rapidly enlarging nodules that may be infectious in etiology. Lung-RADS v2022, released in November 2022, provides several updates including guidance on the classification and management of atypical pulmonary cysts, juxtapleural nodules, airway-centered nodules, and potentially infectious findings. This new release also provides clarification for determining nodule growth and introduces stepped management for nodules that are stable or decreasing in size. This article summarizes the current evidence and expert consensus supporting Lung-RADS v2022.

Effect of lower tube voltage on the reproducibility of right-to-left ventricular diameter ratio measurements on computed tomographic pulmonary angiography images.

OBJECTIVE: This study aimed to evaluate the interobserver variability of right-to-left ventricular (RV/LV) diameter ratios on computed tomographic pulmonary angiographies at reduced tube potential. METHODS: Consecutive computed tomographic pulmonary angiographies performed at 80 kVp for subjects weighing less than 80 kg (n = 40) and 100 kVp for those weighing 80 kg or greater (n = 40) were selected as the low peak kilovoltage cohort, with age- and sex-matched studies performed at 120 kVp forming the controls (n = 40 each). The interobserver variability in RV/LV diameter ratio on axial and 4-chamber images was evaluated. RESULTS: Interobserver correlation was excellent at both reduced tube voltages (correlation coefficients, 0.81-0.91; P < 0.001). Bland-Altman plots indicated higher variability at lower peak kilovoltage, confirmed only for axial measurements by multivariate regression adjusting for body weight and ventricular ratio (ß coefficient = 0.04 and 0.03, P = 0.049 and 0.022, for 80 kVp and 100 kVp, respectively). CONCLUSIONS: Lower tube voltage did not affect the reproducibility of RV/LV diameter ratio on 4-chamber images; for axial measurements, the increase in variability was 3% to 4% of the average ventricular ratio.

Developing Validated Tools to Identify Pulmonary Embolism in Electronic Databases: Rationale and Design of the PE-EHR+ Study.

BACKGROUND: Contemporary pulmonary embolism (PE) research, in many cases, relies on data from electronic health records (EHRs) and administrative databases that use International Classification of Diseases (ICD) codes. Natural language processing (NLP) tools can be used for automated chart review and patient identification. However, there remains uncertainty with the validity of ICD-10 codes or NLP algorithms for patient identification. METHODS: The PE-EHR+ study has been designed to validate ICD-10 codes as Principal Discharge Diagnosis, or Secondary Discharge Diagnoses, as well as NLP tools set out in prior studies to identify patients with PE within EHRs. Manual chart review by two independent abstractors by predefined criteria will be the reference standard. Sensitivity, specificity, and positive and negative predictive values will be determined. We will assess the discriminatory function of code subgroups for intermediate- and high-risk PE. In addition, accuracy of NLP algorithms to identify PE from radiology reports will be assessed. RESULTS: A total of 1,734 patients from the Mass General Brigham health system have been identified. These include 578 with ICD-10 Principal Discharge Diagnosis codes for PE, 578 with codes in the secondary position, and 578 without PE codes during the index hospitalization. Patients within each group were selected randomly from the entire pool of patients at the Mass General Brigham health system. A smaller subset of patients will also be identified from the Yale-New Haven Health System. Data validation and analyses will be forthcoming. CONCLUSIONS: The PE-EHR+ study will help validate efficient tools for identification of patients with PE in EHRs, improving the reliability of efficient observational studies or randomized trials of patients with PE using electronic databases.

Axial and reformatted four-chamber right ventricle-to-left ventricle diameter ratios on pulmonary CT angiography as predictors of death after acute pulmonary embolism.

OBJECTIVE: The purpose of this article is to retrospectively compare right ventricular-to-left ventricular (RV/LV) diameter ratios measured on the standard axial view versus the reformatted four-chamber view as predictors of mortality after acute pulmonary embolism (PE). MATERIALS AND METHODS: Six hundred seventy-four consecutive patients (mean age, 58 years; 372 women) with a diagnosis of acute PE on pulmonary CT angiography were considered. The axial and reformatted four-chamber RV/LV diameter ratios were compared as predictors of 30-day all-cause and PE-related mortality. RESULTS: Ninety-seven patients (14%) died within 30 days; 39 deaths were PE related. There was no significant difference in the univariate hazard ratios (HRs) of axial and four-chamber RV/LV diameter ratios greater than 0.9 for both all-cause (HR, 2.13 [95% CI, 1.29-3.51] vs HR, 1.95 [95% CI, 1.22-3.14]; p = 0.74) and PE-related (HR, 19.6 [95% CI, 2.70-143] vs HR, 21.8 [95% CI, 2.99-158]; p = 1.0) mortality. Axial and four-chamber multivariate HRs accounting for potential confounders such as age and cancer were also similar for all-cause (HR, 1.79 [95% CI, 1.07-2.99] vs HR, 1.54 [95% CI, 0.95-2.49]; p = 0.62) and PE-related (HR, 16.3 [95% CI, 2.22-119] vs HR, 17.7 [95% CI, 2.43-130]; p = 1.0) mortality. There was no significant difference in sensitivity, specificity, negative predictive value, or positive predictive value. Axial and four-chamber measurements were well correlated (correlation coefficient, 0.857), and there was no significant difference in overall accuracy for predicting all-cause (area under the curve [AUC], 0.582 vs 0.577; p = 0.72) and PE-related (AUC, 0.743 vs 0.744; p = 1.0) mortality. CONCLUSION: The axial RV/LV diameter ratio is no less accurate than the reformatted four-chamber RV/LV diameter ratio for predicting 30-day mortality after PE.

Significance of Right-to-Left Ventricular Ratio as a Quantitative Computed Tomography Biomarker in Patients With Negative Computed Tomography Pulmonary Angiograms.

PURPOSE: The purpose of our study was to determine if the ratio of right-to-left ventricular diameter (RV/LV ratio) on computed tomography (CT) pulmonary angiograms (CTPA) is predictive of 90-day mortality in patients without pulmonary embolism (PE). MATERIALS AND METHODS: This Institutional Review Board-approved single-institution retrospective study was performed on patients who underwent CTPA in the emergency or inpatient setting over a 1-year period. Right and left ventricular diameters were measured and RV/LV ratios calculated for patients without acute PE. Ratios greater than or equal to 0.9 were considered abnormal. Univariate analysis was performed for the outcome of death within 90 days of CT. Multivariable analysis was also performed to control for age, sex, and lung disease. RESULTS: Of the 423 patients included in the study, 55 patients died within 90 days of CT. An RV/LV ratio ≥0.9 was predictive of 90-day mortality: of the 226 patients with RV/LV ≥0.9, 42 (18.6%) died within 90 days, compared with 13 of 197 patients without abnormal ratio (6.6%), with odds ratio (OR) of 3.23 (95% confidence interval [CI]: 1.68-6.22; P<0.01). In multivariate analysis, RV/LV ratio had an OR of 5.19 per unit increase (95%CI: 1.06-25.42; P=0.04); age had an OR of 1.04 per year increase (95% CI: 1.01-1.06; P<0.01). CONCLUSION: Increased RV/LV ratio is a negative prognostic factor even in patients without acute PE and may be a useful CT biomarker to include in radiology reports for all patients undergoing CTPA.