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.

A common polymorphism in the Intelectin-1 gene influences mucus plugging in severe asthma.

By incompletely understood mechanisms, type 2 (T2) inflammation present in the airways of severe asthmatics drives the formation of pathologic mucus which leads to airway mucus plugging. Here we investigate the molecular role and clinical significance of intelectin-1 (ITLN-1) in the development of pathologic airway mucus in asthma. Through analyses of human airway epithelial cells we find that ITLN1 gene expression is highly induced by interleukin-13 (IL-13) in a subset of metaplastic MUC5AC+ mucus secretory cells, and that ITLN-1 protein is a secreted component of IL-13-induced mucus. Additionally, we find ITLN-1 protein binds the C-terminus of the MUC5AC mucin and that its deletion in airway epithelial cells partially reverses IL-13-induced mucostasis. Through analysis of nasal airway epithelial brushings, we find that ITLN1 is highly expressed in T2-high asthmatics, when compared to T2-low children. Furthermore, we demonstrate that both ITLN-1 gene expression and protein levels are significantly reduced by a common genetic variant that is associated with protection from the formation of mucus plugs in T2-high asthma. This work identifies an important biomarker and targetable pathways for the treatment of mucus obstruction in asthma.

Technology Characterization Through Diverse Evaluation Methodologies: Application to Thoracic Imaging in Photon-Counting Computed Tomography.

OBJECTIVE: Different methods can be used to condition imaging systems for clinical use. The purpose of this study was to assess how these methods complement one another in evaluating a system for clinical integration of an emerging technology, photon-counting computed tomography (PCCT), for thoracic imaging. METHODS: Four methods were used to assess a clinical PCCT system (NAEOTOM Alpha; Siemens Healthineers, Forchheim, Germany) across 3 reconstruction kernels (Br40f, Br48f, and Br56f). First, a phantom evaluation was performed using a computed tomography quality control phantom to characterize noise magnitude, spatial resolution, and detectability. Second, clinical images acquired using conventional and PCCT systems were used for a multi-institutional reader study where readers from 2 institutions were asked to rank their preference of images. Third, the clinical images were assessed in terms of in vivo image quality characterization of global noise index and detectability. Fourth, a virtual imaging trial was conducted using a validated simulation platform (DukeSim) that models PCCT and a virtual patient model (XCAT) with embedded lung lesions imaged under differing conditions of respiratory phase and positional displacement. Using known ground truth of the patient model, images were evaluated for quantitative biomarkers of lung intensity histograms and lesion morphology metrics. RESULTS: For the physical phantom study, the Br56f kernel was shown to have the highest resolution despite having the highest noise and lowest detectability. Readers across both institutions preferred the Br56f kernel (71% first rank) with a high interclass correlation (0.990). In vivo assessments found superior detectability for PCCT compared with conventional computed tomography but higher noise and reduced detectability with increased kernel sharpness. For the virtual imaging trial, Br40f was shown to have the best performance for histogram measures, whereas Br56f was shown to have the most precise and accurate morphology metrics. CONCLUSION: The 4 evaluation methods each have their strengths and limitations and bring complementary insight to the evaluation of PCCT. Although no method offers a complete answer, concordant findings between methods offer affirmatory confidence in a decision, whereas discordant ones offer insight for added perspective. Aggregating our findings, we concluded the Br56f kernel best for high-resolution tasks and Br40f for contrast-dependent tasks.

Evaluation and Utilization of Flow Artifacts at CT.

Flow artifacts are commonly encountered at contrast-enhanced CT and can be difficult to discern from true pathologic conditions. Therefore, radiologists must be comfortable distinguishing flow artifacts from true pathologic conditions. This is of particular importance when evaluating the pulmonary arteries and aorta, as a flow artifact may be mistaken for a pulmonary embolism or dissection flap. Understanding the mechanics of flow artifacts and how these artifacts are created can help radiologists in several ways. First, this knowledge can help radiologists appreciate how the imaging characteristics of flow artifacts differ from true pathologic conditions. This information can also help radiologists better recognize the clinical conditions that predispose patients to flow artifacts, such as pneumonia, chronic lung damage, and altered cardiac output. By understanding when flow artifacts may be confounding the interpretation of an examination, radiologists can then know when to pursue other troubleshooting methods to assist with the diagnosis. In these circumstances, the radiologist can consider several troubleshooting methods, including adjusting the imaging protocols, recommending when additional imaging may be helpful, and suggesting which imaging study would be the most beneficial. Finally, flow artifacts can also be used as a diagnostic tool when evaluating the vascular anatomy, examples of which include the characterization of shunts, venous collaterals, intimomedial flaps, and alternative patterns of blood flow, as seen in extracorporeal membrane oxygenation circuits. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Persistent mucus plugs in proximal airways are consequential for airflow limitation in asthma.

BACKGROUNDInformation about the size, airway location, and longitudinal behavior of mucus plugs in asthma is needed to understand their role in mechanisms of airflow obstruction and to rationally design muco-active treatments.METHODSCT lung scans from 57 patients with asthma were analyzed to quantify mucus plug size and airway location, and paired CT scans obtained 3 years apart were analyzed to determine plug behavior over time. Radiologist annotations of mucus plugs were incorporated in an image-processing pipeline to generate size and location information that was related to measures of airflow.RESULTSThe length distribution of 778 annotated mucus plugs was multimodal, and a 12 mm length defined short ("stubby", ≤12 mm) and long ("stringy", >12 mm) plug phenotypes. High mucus plug burden was disproportionately attributable to stringy mucus plugs. Mucus plugs localized predominantly to airway generations 6-9, and 47% of plugs in baseline scans persisted in the same airway for 3 years and fluctuated in length and volume. Mucus plugs in larger proximal generations had greater effects on spirometry measures than plugs in smaller distal generations, and a model of airflow that estimates the increased airway resistance attributable to plugs predicted a greater effect for proximal generations and more numerous mucus plugs.CONCLUSIONPersistent mucus plugs in proximal airway generations occur in asthma and demonstrate a stochastic process of formation and resolution over time. Proximal airway mucus plugs are consequential for airflow and are in locations amenable to treatment by inhaled muco-active drugs or bronchoscopy.TRIAL REGISTRATIONClinicaltrials.gov; NCT01718197, NCT01606826, NCT01750411, NCT01761058, NCT01761630, NCT01716494, and NCT01760915.FUNDINGAstraZeneca, Boehringer-Ingelheim, Genentech, GlaxoSmithKline, Sanofi-Genzyme-Regeneron, and TEVA provided financial support for study activities at the Coordinating and Clinical Centers beyond the third year of patient follow-up. These companies had no role in study design or data analysis, and the only restriction on the funds was that they be used to support the SARP initiative.

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.

Image quality of photon counting and energy integrating chest CT - Prospective head-to-head comparison on same patients.

PURPOSE: To prospectively compare the image quality of high-resolution, low-dose photon-counting detector CT (PCD-CT) with standard energy-integrating-detector CT (EID) on the same patients. METHOD: IRB-approved, prospective study; patients received same-day non-contrast CT on EID and PCD-CT (NAEOTOM Alpha, blinded) with clinical protocols. Four blinded radiologists evaluated subsegmental bronchial wall definition, noise, and overall image quality in randomized order (0 = worst; 100 = best). Cases were quantitatively compared using the average Global-Noise-Index (GNI), Noise-Power-Spectrum average frequency (fav), NPS frequency-peak (fpeak), Task-Transfer-Function-10%-frequency (f10) an adjusted detectability index (d'adj), and applied output radiation doses (CTDIvol). RESULTS: Sixty patients were prospectively imaged (27 men, mean age 67 ± 10 years, mean BMI 27.9 ± 6.5, 15.9-49.4 kg/m2). Subsegmental wall definition was rated significantly better for PCD-CT than EID (mean 71 [56-87] vs 60 [45-76]; P < 0.001), noise was rated higher for PCD-CT (48 [26-69] vs 34 [13-56]; P < 0.001). Overall image quality was rated significantly higher for PCD-CT than EID (66 [48-85] vs 61 [42-79], P = 0.008). Automated image quality measures showed similar differences for PCD-CT vs EID (mean GNI 70 ± 19 HU vs 26 ± 8 HU, fav 0.35 ± 0.02 vs 0.25 ± 0.02 mm-1, fpeak 0.07 ± 0.01 vs 0.09 ± 0.03 mm-1, f10 0.7 ± 0.08 vs 0.6 ± 0.1 mm-1, all p-values < 0.001). PCD-CT showed a 10% average d'adj increase (-49% min, 233% max). PCD-CT studies were acquired at significantly lower radiation doses than EID (mean CTDIvol 4.5 ± 2.1 vs 7.7 ± 3.2 mGy, P < 0.01). CONCLUSION: Though PCD-CT had higher measured and perceived noise, it offered equivalent or better diagnostic quality compared to EID at lower radiation doses, due to its improved resolution.

CT Approach to Lung Injury.

Diffuse alveolar damage (DAD), which represents the pathologic changes seen after acute lung injury, is caused by damage to all three layers of the alveolar wall and can ultimately result in alveolar collapse with loss of the normal pulmonary architecture. DAD has an acute phase that predominantly manifests as airspace disease at CT owing to filling of the alveoli with cells, plasma fluids, and hyaline membranes. DAD then evolves into a heterogeneous organizing phase, with mixed airspace and interstitial disease characterized by volume loss, architectural distortion, fibrosis, and parenchymal loss. Patients with DAD have a severe clinical course and typically require prolonged mechanical ventilation, which may result in ventilator-induced lung injury. In those patients who survive DAD, the lungs will remodel over time, but most will have residual findings at chest CT. Organizing pneumonia (OP) is a descriptive term for a histologic pattern characterized by intra-alveolar fibroblast plugs. The significance and pathogenesis of OP are controversial. Some authors regard it as part of a spectrum of acute lung injury, while others consider it a marker of acute or subacute lung injury. At CT, OP manifests with various forms of airspace disease that are most commonly bilateral and relatively homogeneous in appearance at individual time points. Patients with OP most often have a mild clinical course, although some may have residual findings at CT. In patients with DAD and OP, imaging findings can be combined with clinical information to suggest the diagnosis in many cases, with biopsy reserved for difficult cases with atypical findings or clinical manifestations. To best participate in the multidisciplinary approach to patients with lung injury, radiologists must not only recognize these entities but also describe them with consistent and meaningful terminology, examples of which are emphasized in the article. © RSNA, 2023 See the invited commentary by Kligerman et al in this issue. Quiz questions for this article are available in the supplemental material.

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.

Intraoral Formation of a Rigid Obturator for the Treatment of Dental Fistulae and Draining Tracts in the Horse.

A retrospective cohort study to describe a novel use of a mechanically retained, rigid obturator (RO) to manage maxillary and mandibular persistent pathologic oral communications (PPOCs). This study included 22 horses with PPOC with at least 6 months of follow-up after treatment with a RO. The RO was made with a flowable, bis-acryl-based composite resin. Medical records were analyzed, including case details, obtained imaging, surgical reports, and follow-up information. There were 10 horses that had follow-up examinations by the authors and 8 horses by the referring veterinarian; in 4 horses, follow-up information was obtained by informal telephone interviews with the owner. Complete resolution of clinical signs was obtained in 21 of 22 (95.5%) horses, with confirmed healing of the PPOC in 15 of 22 (68.2%) horses. Complications were noted in 7 of 22 (31.8%) cases. Complications included: complete loss of RO (2 horses), fracture/defect of the RO (2 horses), displaced/shifted RO (1 horse), and incomplete seal of the PPOC (2 horses). All complications were resolved by repairing or replacing the RO. The RO placement is a successful, noninvasive, easily repeatable treatment for PPOC.

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.

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® Suspected Pulmonary Embolism: 2022 Update.

Pulmonary embolism (PE) remains a common and important clinical condition that cannot be accurately diagnosed on the basis of signs, symptoms, and history alone. The diagnosis of PE has been facilitated by technical advancements and multidetector CT pulmonary angiography, which is the major diagnostic modality currently used. Ventilation and perfusion scans remain largely accurate and useful in certain settings. MR angiography can be useful in some clinical scenarios and lower-extremity ultrasound can substitute by demonstrating deep vein thrombosis; however, if negative, further studies to exclude PE are indicated. In all cases, correlation with the clinical status, particularly with risk factors, improves not only the accuracy of diagnostic imaging but also overall utilization. Other diagnostic tests have limited roles. 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.

Imaging of Smoking and Vaping Related Diffuse Lung Injury.

Lung injury associated with smoking tobacco or other substances results in a variety of clinical presentations and imaging patterns, depending on mechanism of injury and substance inhaled. Patients may present in the acute setting, as in the case of acute eosinophilic pneumonia, e-cigarette or vaping product use-associated lung injury, crack lung, or heroin inhalation. They may present with subacute shortness of breath and demonstrate findings of pulmonary Langerhans cell histiocytosis, respiratory bronchiolitis, or desquamative interstitial pneumonia. Alternatively, they may present with chronic dyspnea and demonstrate findings of emphysema or smoking-related interstitial lung fibrosis.

Update on the limited sensitivity of computed tomography relative to RT-PCR for COVID-19: a systematic review.

Purpose: The global and ongoing COVID-19 outbreak has compelled the need for timely and reliable methods of detection for SARS-CoV-2 infection. Although reverse transcription-polymerase chain reaction (RT-PCR) has been widely accepted as a reference standard for COVID-19 diagnosis, several early studies have suggested the superior sensitivity of computed tomography (CT) in identifying SARS-CoV-2 infection. In a previous systematic review, we stratified studies based on risk for bias to evaluate the true sensitivity of CT for detecting SARS-CoV-2 infection. This study revisits our prior analysis, incorporating more current data to assess the sensitivity of CT for COVID-19. Material and methods: The PubMed and Google Scholar databases were searched for relevant articles published between 1 January 2020, and 25 April 2021. Exclusion criteria included lack of specification regarding whether the study cohort was adult or paediatric, whether patients were symptomatic or asymptomatic, and not identifying the source of RT-PCR specimens. Ultimately, 62 studies were included for systematic review and were subsequently stratified by risk for bias using the QUADAS-2 quality assessment tool. Sensitivity data were extracted for random effects meta-analyses. Results: The average sensitivity for COVID-19 reported by the high-risk-of-bias studies was 68% [CI: 58, 80; range: 38-96%] for RT-PCR and 91% [CI: 87, 96; range: 47-100%] for CT. The average sensitivity reported by the low-risk-of-bias studies was 84% [CI: 0.75, 0.94; range: 70-97%] for RT-PCR and 78% [CI: 71, 0.86; range: 44-92%] for CT. Conclusions: On average, the high-risk-of bias studies underestimated the sensitivity of RT-PCR and overestimated the sensitivity of CT for COVID-19. Given the incorporation of recently published low-risk-of-bias articles, the sensitivities according to low-risk-of-bias studies for both RT-PCR and CT were higher than previously reported.

Use of a novel helical fan beam imaging system for computed tomography of the head and neck in sedated standing horses: 120 cases (2019-2020).

OBJECTIVE: To evaluate the diagnostic capabilities of a novel helical fan beam CT system used for imaging of horses with clinical problems of the head and neck. ANIMALS: 120 horses. PROCEDURES: Medical records were reviewed of horses presented for CT of the head or neck at 2 university hospitals. The following data were recorded: age, sex, breed, presenting complaint, sedation used for imaging, scanning time, procedure time, other diagnostic imaging methods performed, imaging diagnosis, clinical diagnosis, and complications during imaging. RESULTS: Quarter Horses and Warmbloods were the most common breeds, and the most common complaint was nasal discharge. The head (101/120 [84%] horses) was scanned most frequently, and the most common diagnoses were primary dental disease and a space-occupying lesion of the paranasal sinuses. Nuchal bursitis was the most common imaging diagnosis in the neck region. Procedure time ranged from 20 to 45 minutes with a scanning time of 30 to 40 seconds. No complications with horse sedation occurred, and horses tolerated scanning well. An imaging diagnosis was more frequently achieved with CT (109/120 [91%] horses) than with planar digital radiography (23/61 [38%] horses). CLINICAL RELEVANCE: The helical fan beam CT system had fast scanning times and could be used safely for routine imaging of the teeth and sinuses in horses. The caudal extent of scanning in the neck region was limited by the shape of the horse's neck and thorax.

Long-Term Outcome of Horses Undergoing Unilateral Mandibular Condylectomy and Meniscectomy for Temporomandibular Joint Disease.

Background: There are no reports describing the long-term outcome of sport horses undergoing unilateral mandibular condylectomy with meniscectomy (UMC) for treatment for severe temporomandibular joint (TMJ) disease (TMD). Whether horses undergoing UMC require a specialized diet, can return to riding with a bit, or return to intended function after surgery is unknown. Objective: To determine the long-term outcome of horses undergoing UMC for treatment of severe TMD. Study Design: A multi-institutional, retrospective study. Methods: Medical records obtained from seven equine referral hospitals of horses with severe TMD that underwent UMC were reviewed. Details regarding the presenting complaints, results of clinical examination, findings of diagnostic imaging, surgical technique, and outcome (including long-term follow-up with an owner questionnaire) were recorded. Results: Eleven horses fit the inclusion criteria. Three had severe idiopathic osteoarthritis, and eight had confirmed septic osteoarthritis of the TMJ. The most common post-operative complications were drainage and peri-incisional swelling (n = 5). One horse developed a hematoma at the surgical site because the facial artery was inadvertently transected during the approach, causing the condylectomy to be postponed. All horses were discharged alive from the hospital, and 10 returned to their previous or intended use. All had complete resolution of clinical signs of TMD. One mare was retired from athletic use due to her genetic value as a broodmare. One horse was euthanized 2 years after UMC due to progressively worsening of clinical signs of temporohyoid osteoarthropathy (THO), which were not present before surgery. When available, owner satisfaction of the results of the procedure was excellent. Main Limitations: Sample size; multiple institutions; owner bias. Conclusions: Unilateral mandibular condylectomy should not be considered a salvage procedure. Horses treated for severe TMD by UMC can return to their previous or intended level of athletic performance and do not require a specialized diet.

Predictive Value of Coronary Artery Calcium in Patients Receiving Computed Tomography Pulmonary Angiography for Suspected Pulmonary Embolism in the Emergency Department.

PURPOSE: Coronary artery calcium (CAC) is a frequent incidental finding on computed tomography pulmonary angiogram (CTPA) in the evaluation of pulmonary embolism (PE) in the emergency department (ED); however, its prognostic value is unclear. In this study, we interrogate the prognostic value of CAC identified on CTPA in predicting adverse outcomes in the evaluation of PE in the ED. MATERIALS AND METHODS: In this retrospective cohort study, we identified 610 patients presenting to the ED in 2013 and evaluated with CTPA for suspected PE. Ordinal CAC scores were evaluated as absent (0), mild (1), moderate (2), or severe (3) in each of the 4 main coronary arteries. Composite CAC scores were subsequently compared against adverse clinical outcomes, defined as intensive care unit admission, hospital stay longer than 72 hours, or death during hospital course or at 6-month follow-up, using univariate and multivariate logistic regression analyses. Relevant exclusion criteria included a history of cardiovascular disease. RESULTS: In all, 365 patients met the inclusion criteria (231 women, mean age 56±16 y) with 132 patients (36%) having some degree of CAC and 16 (4%) having severe CAC. Known malignancy was present in 151 (41%) patients and composite adverse clinical outcomes were observed in 98 patients (32%). Age, presence of acute PE, malignancy, and presence of CAC were significant predictors of adverse outcomes on both univariate and multivariate analyses. CAC was not an independent predictor of short-term adverse outcomes on multivariate analysis ( P =0.06) when all patients were considered. However, when patients with known malignancy were excluded, CAC was an independent predictor of short-term adverse outcomes (odds ratio=2.5, confidence interval=1.1-5.5, P =0.03) independent of age and presence of PE. CONCLUSION: The presence of CAC on CT PA was predictive of adverse outcomes in patients without known cardiac disease presenting to the ED with suspected PE.