Interpretation of chest radiography in patients with known or suspected SARS-CoV-2 infection: what we learnt from comparison with computed tomography.

Differently from computed tomography (CT), well-defined terminology for chest radiography (CXR) findings and standardized reporting in the setting of known or suspected COVID-19 are still lacking. We propose a revision of CXR major imaging findings in SARS-CoV-2 pneumonia derived from the comparison of CXR and CT, suggesting a precise and standardized terminology for CXR reporting. This description will consider asymptomatic patients, symptomatic patients, and patients with SARS-CoV-2-related pulmonary complications. We suggest using terms such as ground-glass opacities, consolidation, and reticular pattern for the most common findings, and characteristic chest radiographic pattern in presence of one or more of the above-mentioned findings with peripheral and mid-to-lower lung zone distribution.

Effects of Prone Position on Lung Recruitment and Ventilation-Perfusion Matching in Patients With COVID-19 Acute Respiratory Distress Syndrome: A Combined CT Scan/Electrical Impedance Tomography Study.

OBJECTIVES: Prone positioning allows to improve oxygenation and decrease mortality rate in COVID-19-associated acute respiratory distress syndrome (C-ARDS). However, the mechanisms leading to these effects are not fully understood. The aim of this study is to assess the physiologic effects of pronation by the means of CT scan and electrical impedance tomography (EIT). DESIGN: Experimental, physiologic study. SETTING: Patients were enrolled from October 2020 to March 2021 in an Italian dedicated COVID-19 ICU. PATIENTS: Twenty-one intubated patients with moderate or severe C-ARDS. INTERVENTIONS: First, patients were transported to the CT scan facility, and image acquisition was performed in prone, then supine position. Back to the ICU, gas exchange, respiratory mechanics, and ventilation and perfusion EIT-based analysis were provided toward the end of two 30 minutes steps (e.g., in supine, then prone position). MEASUREMENTS AND MAIN RESULTS: Prone position induced recruitment in the dorsal part of the lungs (12.5% ± 8.0%; p < 0.001 from baseline) and derecruitment in the ventral regions (-6.9% ± 5.2%; p < 0.001). These changes led to a global increase in recruitment (6.0% ± 6.7%; p < 0.001). Respiratory system compliance did not change with prone position (45 ± 15 vs 45 ± 18 mL/cm H2O in supine and prone position, respectively; p = 0.957) suggesting a decrease in atelectrauma. This hypothesis was supported by the decrease of a time-impedance curve concavity index designed as a surrogate for atelectrauma (1.41 ± 0.16 vs 1.30 ± 0.16; p = 0.001). Dead space measured by EIT was reduced in the ventral regions of the lungs, and the dead-space/shunt ratio decreased significantly (5.1 [2.3-23.4] vs 4.3 [0.7-6.8]; p = 0.035), showing an improvement in ventilation-perfusion matching. CONCLUSIONS: Several changes are associated with prone position in C-ARDS: increased lung recruitment, decreased atelectrauma, and improved ventilation-perfusion matching. These physiologic effects may be associated with more protective ventilation.

Use of Chest Imaging in the Diagnosis and Management of COVID-19: A WHO Rapid Advice Guide.

The World Health Organization (WHO) undertook the development of a rapid guide on the use of chest imaging in the diagnosis and management of coronavirus disease 2019 (COVID-19). The rapid guide was developed over 2 months by using standard WHO processes, except for the use of "rapid reviews" and online meetings of the panel. The evidence review was supplemented by a survey of stakeholders regarding their views on the acceptability, feasibility, impact on equity, and resource use of the relevant chest imaging modalities (chest radiography, chest CT, and lung US). The guideline development group had broad expertise and country representation. The rapid guide includes three diagnosis recommendations and four management recommendations. The recommendations cover patients with confirmed or who are suspected of having COVID-19 with different levels of disease severity, throughout the care pathway from outpatient facility or hospital entry to home discharge. All recommendations are conditional and are based on low certainty evidence (n = 2), very low certainty evidence (n = 2), or expert opinion (n = 3). The remarks accompanying the recommendations suggest which patients are likely to benefit from chest imaging and what factors should be considered when choosing the specific imaging modality. The guidance offers considerations about implementation, monitoring, and evaluation, and also identifies research needs. Published under a CC BY 4.0 license. Online supplemental material is available for this article.

Clinical-radiological correlations in COVID-19-related venous thromboembolism: Preliminary results from a multidisciplinary study.

INTRODUCTION: Among the multiple complex pathophysiological mechanisms underlying COVID-19 pneumonia, immunothrombosis has been shown to play a key role. One of the most dangerous consequences of the prothrombotic imbalance is the increased incidence of micro- and macrothrombotic phenomena, especially deep vein thrombosis (DVT) and pulmonary embolism (PE). METHODS: We investigated the correlation between radiological and clinical-biochemical characteristics in a cohort of hospitalised COVID-19 patients. RESULTS: PE was confirmed in 14/61 (23%) patients, five (35.7%) had DVT. The radiographic findings, quantified by Qanadli score calculated on CT angiography, correlated with the clinical score and biochemical markers. The ratio between the right and left ventricle diameter measured at CT angiography correlated with the length of hospital stay. CONCLUSION: In our cohort radiological parameters showed a significant correlation with clinical prognostic indices and scores, thus suggesting that a multidisciplinary approach is advisable in the evaluation of PE in COVID-19 patients.

Diagnostic performance of chest radiography in high COVID-19 prevalence setting: experience from a European reference hospital.

PURPOSE: The study's aim is to analyse the diagnostic performance of chest radiography (CXR) in patients with suspected coronavirus disease 19 (COVID-19). METHODS: We retrospectively considered 826 consecutive patients with suspected COVID-19 presenting to our emergency department (ED) from February 21 to March 31, 2020, in a high disease prevalence setting. We enrolled patients who underwent CXR and rhino-oropharyngeal swab for real-time reverse transcription-polymerase chain reaction (rRT-PCR). CXRs were evaluated by an expert radiologist; a second independent analysis was performed by two residents in consensus. All readers, blinded to rRT-PCR results, classified CXRs positive/negative depending on presence/absence of typical findings of COVID-19, using rRT-PCR as reference standard. RESULTS: We finally analysed 680 patients (median age 58); 547 (80%) tested positive for COVID-19. The diagnostic performance of CXR, interpreted by the expert reader, was as follows: sensitivity (79.0%; 95% CI: 75.3-82.3), specificity (81.2%; 95% CI: 73.5-87.5), PPV (94.5%;95% CI: 92.0-96.4), NPV (48.4%; 95% CI: 41.7-55.2), and accuracy (79.3%; 95% CI: 76.0-82.2). For the residents: sensitivity (75.1%; 95% CI: 71.2-78.7), specificity (57.9%; 95% CI: 49.9-66.4), PPV (88.0%; 95% CI: 84.7-90.8), NPV (36.2%; 95% CI: 29.7-43.0), and accuracy (71.6%; 95% CI: 68.1-75.0). We found a significant difference between the reporting sensitivity (p = 0.013) and specificity (p < 0.0001) of expert radiologist vs residents. CXR sensitivity was higher in patients with symptom onset > 5 days before ED presentation compared to ≤ 5 days (84.4% vs 70.7%). CONCLUSIONS: CXR showed a sensitivity of 79% and a specificity of 81% in diagnosing viral pneumonia in symptomatic patients with clinical suspicion of COVID-19. Further studies in lower prevalence settings are needed.

Performance of CT Colonography in Diagnosis of Synchronous Colonic Lesions in Patients With Occlusive Colorectal Cancer.

OBJECTIVE. The purpose of this study was to evaluate the accuracy of CT colonography (CTC) in the diagnosis of synchronous colonic lesions in a cohort of patients with an occlusive colorectal cancer (CRC) causing incomplete colonoscopy. SUBJECTS AND METHODS. Among 109 patients with CRC causing incomplete colonoscopy who underwent CTC with IV contrast enhancement after cathartic purgation, fecal tagging, and colon distention, 70 (mean age, 70 years) for whom reference standards (surgical reports, first surveillance colonoscopy) were available were evaluated. Per-patient and per-lesion sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of CTC in the diagnosis of synchronous colonic lesions measuring 6 mm or larger were assessed. RESULTS. Twenty-seven of the 70 patients (39%) had at least one 6-mm or larger synchronous lesion, and four patients (6%) had a total of five synchronous CRCs. Per-patient sensitivity in diagnosing synchronous CRC was 1.00 (4/4). There were 59 lesions: 20 with a diameter of 10 mm or greater; 30, 6-9 mm; and nine, 5 mm or less. The overall per-patient CTC sensitivity in detecting synchronous lesions 6 mm or larger was 0.93 (25/27); specificity, 0.98 (42/43); PPV, 0.96; and NPV, 0.95. Per-patient sensitivity for the diagnosis of synchronous advanced neoplasia (advanced adenoma and colorectal cancers) was 0.94 (15/16). Per-lesion CTC sensitivity for detecting synchronous lesions 6 mm or larger was 0.88 (37/42); all adenomatous lesions, 0.89 (55/62); and advanced neoplasia, 0.92 (22/24). CONCLUSION. CTC is a highly accurate test for detecting synchronous colonic lesions in patients with occlusive CRC. The prevalence of advanced neoplasia is high (23%).

Is Carotid Plaque Contrast Enhancement on MRI Predictive for Cerebral or Cardiovascular Events? A Prospective Cohort Study.

OBJECTIVE: The aim of this study was to correlate carotid plaque contrast enhancement (CPCE) to onset of cerebral/cardiovascular events (CCVE) in patients with atherosclerotic carotid disease. METHODS: The ethics committee approved this prospective study. Patients with carotid artery stenosis underwent magnetic resonance angiography before/after injection of 0.1 mmol/kg of gadobenate dimeglumine. Carotid plaque contrast enhancement was graded as follows: 0, no CPCE; 1, 1 single enhancement focus; 2, 2 or more foci. RESULTS: Seventy-seven patients (71 ± 9 years) had a stenosis degree: 34 mild, 16 moderate, 27 severe at the right side, and 36, 15, and 25 at the left side. Carotid plaque contrast enhancement was 0 in 30 patients, 1 in 26, 2 in 11 at the right, and 37, 19, and 13 at the left. Forty-seven CCVE occurred after magnetic resonance imaging, correlated to both stenosis degree (P = 0.006) and CPCE (P = 0.032). Excluding surgery/stenting, the correlation held only for CPCE (P = 0.017). Of 49 patients showing CPCE, 5 (10%) reported CCVE; of 21 patients without CPCE, none reported CCVE (P = 0.129). CONCLUSIONS: The absence of CPCE seems to be a negative predictor for CCVE.

Diverticular Disease of the Colon: News From Imaging.

Different scenarios embrace computed tomography imaging and diverticula, including asymptomatic (diverticulosis) and symptomatic patients (acute diverticulitis, follow-up of acute diverticulitis, chronic diverticulitis). If the role of computed tomography is validated and widely supported by evidence in case of acute diverticulitis, this is not the case of patients in their follow-up for acute diverticulitis or with symptoms related to diverticula, but without acute inflammation. In these settings, computed tomography colonography is gaining consensus as the preferred radiologic test.

The Current Role of Radiologic and Endoscopic Imaging in the Diagnosis and Follow-Up of Colonic Diverticular Disease.

OBJECTIVE: Colonic diverticular disease is among the most prevalent conditions in Western society and is a common cause for outpatient visits and hospitalizations. The role of imaging is in evolution, but it has proven useful in confirming clinically suspected disease, assessing severity and complications, and directing patient management. CONCLUSION: This review focuses on the current role of radiologic and endoscopic imaging in distinct clinical scenarios of diverticular disease, with emphasis on diverticulitis and its follow-up.

CT colonography: a survey of general practitioners' knowledge and interest.

PURPOSE: To verify the knowledge and interest of general practitioners on computed tomography colonography (CTC). MATERIALS AND METHODS: In 2014, a Web-based questionnaire was proposed to all general practitioners of [Milan, Italy]. The questionnaire consisted of ten questions concerning general practitioners' knowledge about CTC, including application of guidelines in clinical scenarios and diagnostic performance. RESULTS: Out of 1,053 general practitioners, 231 (22%), 155 men and 76 women (mean age 58 years), completed the survey. We found a significant difference between the age of responders and that of non-responders (p = 0.0033). Of the 231 responders, 84% were aware of the possibility of using CTC as a method for examining the colon-rectum. However, only 57% were aware about low X-ray exposure delivered by CTC and about the possibility of using a reduced cleansing protocol. Only 48% were aware that CTC accuracy in diagnosing 10-mm or larger polyps and colorectal cancers was similar to that of conventional colonoscopy, while 62% were informed about CTC advantages in comparison with double-contrast barium enema; 59% thought that CTC had a potential role as a screening test; 85-86% suggested CTC in the case of refused or incomplete conventional colonoscopy; 79% suggested immediate conventional colonoscopy in the case of at least one 10-mm polyp. About 54% usually prescribe one CTC every 4-6 months, while 36% never have, 3% one CTC per month, and 7% one every 2-3 months. Ninety-four per cent declared that they were willing to attend a course on CTC. CONCLUSION: General practitioners have limited knowledge concerning CTC. Radiological societies should fill this gap offering dedicated educational initiatives.

Contrast enhanced chest-MDCT in oncologic patients. Prospective evaluation of the prevalence of incidental pulmonary embolism and added value of thin reconstructions.

OBJECTIVES: To prospectively assess prevalence/characteristics of clinically unsuspected pulmonary embolism (PE) in cancer patients undergoing follow-up chest MDCT and investigate MDCT protocol. METHODS: We evaluated 1013 oncologic patients. MDCT images at 5 and 1.25 mm thickness were independently evaluated. Pulmonary artery opacification degree was assessed. Presence, level, and site of PE were reported. Type of malignancy and metastases were reported for PE-positive patients. RESULTS: After excluding 1.4% (14/1013) of examinations due to inadequate vessel opacification, 999 patients (572 male; mean age:68 ± 12 years; range:26-93 years) entered the study. Prevalence of PE was 5%. There was significant improvement in the sensitivity for both readers in the evaluation of 1.25 mm compared to 5 mm images (46-50% to 82-92%). 30% (15/51) PE were not described by the radiologist in the prospectively issued report; 53 % (27/51) of PE were segmental, 72.5% (37/51) unilateral. The right lower lobe was the most involved (59%). 27% patients had colon cancer, 18% lung cancer. Among PE-positive patients (25 male; mean age 70 ± 10 years; range:44-87 years), 25% (13/51) had lung cancer, 15% (8/51) colon cancer. CONCLUSIONS: Thin reconstructions are essential for PE diagnosis, regardless of reader experience. Regarding oncologic patients, incidental PE diagnosis influences anticoagulation therapy. KEY POINTS: • CT pulmonary angiography is the gold standard for PE diagnosis. • Cancer and oncological treatments are risk factors for PE. • The prevalence of unsuspected PE was 5%. • Thin reconstructions are essential for PE diagnosis regardless of reader experience. • In oncologic patients, PE diagnosis influences anticoagulation therapy.

The Italian consensus to virtual colonoscopy.

OBJECTIVES: To produce an informed consent for CT colonography (CTC), to be diffused by the Italian Society of Radiology, aimed to make patients and referring physicians aware of CTC examination protocol, advantages and disadvantages, limits and potential related risks. MATERIALS AND METHODS: Delphi method was used to create a consensus among experts on an informed consent for CTC. The overall agreement among different consulted specialists was evaluated and ranked using the Cronbach's correlation coefficient (α) at two time points: after the first and the second 'round' of consultation. RESULTS: The Cronbach index was 0.84 at the end of the first round and 0.93 at the end of the second round. The number of disagreements dropped from an overall of 11-5, from the first to the second round. CONCLUSIONS: The experts were able to produce an informed consent for CTC, hoping that this may be the beginning of a process focused on implementation of quality standards in CTC.

The role of imaging specialists as authors of systematic reviews on diagnostic and interventional imaging and its impact on scientific quality: report from the EuroAIM Evidence-based Radiology Working Group.

PURPOSE: To evaluate the inclusion of radiologists or nuclear medicine physicians (imaging specialists) as authors of systematic reviews (SRs) on imaging and imaging-guided diagnostic procedures and to determine the impact of imaging specialists' presence as authors on the overall quality of the reviews. MATERIALS AND METHODS: A MEDLINE and EMBASE search was performed for SRs of diagnostic and interventional image-guided procedures that were published from January 2001 to December 2010. SRs about procedures primarily performed by nonimaging specialists were excluded. The inclusion of imaging specialists among the SR authors and the frequency of publication in imaging journals were evaluated. The quality of a subset of 200 SRs (100 most recent SRs with imaging specialists as authors and 100 most recent SRs without imaging specialists as authors) was rated by using a 12-item modified assessment of multiple SRs (AMSTAR) evaluation tool. Spearman, χ(2), and Mann-Whitney statistics were used. RESULTS: From among 3258 retrieved citations, 867 SRs were included in the study. Neuroimaging had the largest number of SRs (28% [241 of 867]), 41% (354 of 867) of SRs concerned diagnostic performance, and 26% (228 of 867) of SRs were published in imaging journals. Imaging specialists were authors (in any position) in 330 (38%) of 867 SRs; they were first authors of 176 SRs and last authors of 161 SRs. SRs with imaging specialists as authors were more often published in imaging journals than in nonimaging journals (54% [179 of 330] vs 9% [49 of 537]; P < .001). The median number of modified AMSTAR quality indicators was nine in SRs with imaging specialists as authors, while that in SRs without imaging specialists as authors was seven (P = .003). CONCLUSION: Only 38% (330 of 867) of SRs on radiology or nuclear medicine-related imaging published from January 2001 to December 2010 included imaging specialists as authors. However, the inclusion of imaging specialists as authors was associated with a significant increase in the scientific quality (as judged by using a modified AMSTAR scale) of the SR.

Flat lesions missed at conventional colonoscopy (CC) and visualized by CT colonography (CTC): a pictorial essay.

The purpose of this study is to describe our experience with cases of false negative findings at conventional colonoscopy (CC) that were identified by CT colonography (CTC). Conventional colonoscopy (CC) is the universally accepted gold-standard technique for the diagnosis of colonic polyps and cancers, however occasionally this method can generate false negative findings. We present examples of false negatives at CC, correctly identified by CT colonography (CTC), and later confirmed at a second endoscopy, describing the reasons of false negative, when possible.

Bronchial artery hypertrophy is correlated with coronary artery disease.

BACKGROUND: Bronchial arteries support the systemic pulmonary vasculature and physiologically communicate with pulmonary arteries and coronary arteries. While there is evidence supporting the link between pulmonary diseases and bronchial artery hypertrophy (BAH), few data on the correlation between coronary artery disease (CAD) and BAH have been published. PURPOSE: To evaluate a possible association between BAH and CAD in patients without known pulmonary diseases undergoing computed tomography coronary angiography (CTCA). MATERIAL AND METHODS: This retrospective study was approved by the local ethics committee. One hundred patients with varying degrees of CAD underwent CTCA. Patients were stratified into four groups as follows: group I, 25 patients without CAD or with non-significant CAD; group II, 25 untreated patients with significant CAD; group III, 25 stented patients; group IV, 25 patients with coronary artery bypass grafts. The number and diameter of bronchial arteries were recorded. Correlation between age, CAD, and BAH was estimated. RESULTS: One hundred and ninety-nine bronchial arteries were detected. Approximately 51% were hypertrophic (diameter, >1.5 mm) with a mean diameter of 1.7 ± 0.5 mm. Seventy-six patients showed no pulmonary alterations; 24 were found to have previously undiagnosed pulmonary findings, six of which were severe. Presence and degree of CAD correlated with patients' mean age (60 in group I, 68 in group II, 65 in group III, 69 in group IV; P = 0.023), and mean bronchial artery transverse diameter (1.6 mm, 1.7 mm, 1.8 mm, and 2.0 mm, respectively; P = 0.009). The bronchial artery diameter was not associated with pulmonary findings (P = 0.390). CONCLUSION: There is an association between CAD and BAH. In patients with no pulmonary alterations, BAH could be caused by undiagnosed underlying CAD.

Venous Thromboembolism Management throughout the COVID-19 Era: Addressing Acute and Long-Term Challenges.

Background: COVID-19 increases the risk of venous thromboembolism (VTE) through a complex interplay of mechanisms collectively referred to as immunothrombosis. Limited data exist on VTE challenges in the acute setting throughout a dynamic long-term follow-up of COVID-19 patients compared to non-COVID-19 patients. The aim of the study was to investigate acute and long-term management and complications in VTE patients with and without COVID-19. Methods: A prospective, observational, single-center cohort study on VTE patients followed from the acute care stage until 24 months post-diagnosis. Results: 157 patients, 30 with COVID-19-associated VTE and 127 unrelated to COVID-19, were enrolled. The mean follow-up was 10.8 (±8.9) months. COVID-19 patients had fewer comorbidities (1.3 ± 1.29 vs. 2.26 ± 1.68, p < 0.001), a higher proportion of pulmonary embolism at baseline (96.7% vs. 76.4%, p = 0.01), and had a lower probability of remaining on anticoagulant therapy after three months (p < 0.003). The most used initial therapy was low-molecular-weight heparin in 130/157 cases, followed by long-term treatment with direct oral anticoagulants in 123/157. Two (6.7%) COVID-19 vs. three (2.4%) non-COVID-19 patients (p = 0.243) had major hemorrhagic events, all of them within the first three months. Four (3.1%) non-COVID-19 patients had VTE recurrence after six months. Three (2.4%) non-COVID-19 patients developed chronic thromboembolic pulmonary hypertension. There were no fatalities among patients with COVID-19, compared to a mortality of 12/127 (9.4%) in the non-COVID-19 subgroup (p = 0.027). Discussion: Our study offers a comprehensive overview of the evolving nature of VTE management, emphasizing the importance of personalized risk-based approaches, including a limited course of anticoagulation for most COVID-19-associated VTE cases and reduced-dose extended therapy for high-risk subsets.

Diverticular disease severity score based on CT colonography.

OBJECTIVE: We propose a diverticular disease severity score (DDSS) based on CT colonography (CTC) findings. METHODS: Seventy-nine patients (62 ± 14.5 years) underwent CTC after recovering from an episode of acute diverticulitis. Two independent readers classified each case using a four-point scale (DDSS), based on maximum sigmoid colon wall thickness (MSCWT) and minimum lumen diameter at CTC: 1 = MSCWT <3 mm, lumen diameter ≥15 mm; 2 = MSCWT 3-8 mm, lumen diameter ≥5 mm; 3 = MSCWT ≥8 mm, lumen diameter ≥5 mm; 4 = MSCWT ≥8 mm, lumen diameter <5 mm. Intra- and interobserver reproducibility was evaluated. Of 79 patients, 32 (40 %) underwent surgery after CTC; MSCWT was directly measured on the pathological specimen. RESULTS: Intra- and interobserver reproducibility of DDSS were almost perfect (k = 0.90-0.84). DDSS significantly correlated with the probability of surgery (P = 0.001). After surgery, histopathology revealed acute/chronic diverticular inflammation only in 29 cases, and superimposed sigmoid cancer (n = 2) or Crohn's disease (n = 1) in 3 patients with a DDSS of 4. MSCWT at histopathology correlated with DDSS (P = 0.008). CONCLUSION: DDSS is highly reproducible and correlates with pathological MSCWT. Nearly 1 in 3 patients with a DDSS of 4 had significant superimposed histopathology. CTC with DDSS can provide colorectal surgeons with valuable information. KEY POINTS: • A diverticular disease severity score (DDSS) based on CT colonography is proposed. • This DDSS is based on sigmoid colon wall thickness and lumen diameter. • High scores may be associated with relevant coexisting lesions. • A CTC-based DDSS may influence therapeutic decision-making.

Malignant incidental extracardiac findings on cardiac CT: systematic review and meta-analysis.

OBJECTIVE: The objective of our study was to systematically review the evidence on incidental extracardiac findings on cardiac CT with a focus on previously unknown malignancies. MATERIALS AND METHODS: A systematic search was performed (PubMed, EMBASE, Cochrane databases) for studies reporting incidental extracardiac findings on cardiac CT. Among 1099 articles initially found, 15 studies met the inclusion criteria. The references of those articles were hand-searched and 14 additional studies were identified. After review of the full text, 10 articles were excluded. Nineteen studies including 15,877 patients (64% male) were analyzed. A three-level analysis was performed to determine the prevalence of patients with incidental extracardiac findings, the prevalence of patients with major incidental extracardiac findings, and the prevalence of patients with a proven cancer. Heterogeneity was explored for multiple variables. Pooled prevalence and 95% CI were calculated. RESULTS: The prevalence of both incidental extracardiac findings and major incidental extracardiac findings showed a high heterogeneity (I2>95%): The pooled prevalence was 44% (95% CI, 35-54%) and 16% (95% CI, 14-20%), respectively. No significant explanatory variables were found for using or not using contrast material, the size of the FOV, and study design (I2>85%). The pooled cancer prevalence for 10 studies including 5082 patients was 0.7% (95% CI, 0.5-1.0%), with an almost perfect homogeneity (I2<0.1%). Of 29 reported malignancies, 21 (72%) were lung cancers; three, thyroid cancers; two, breast cancers; two, liver cancers; and one, mediastinal lymphoma. CONCLUSION: Although the prevalence of reported incidental extracardiac finding at cardiac CT was highly variable, a homogeneous prevalence of previously unknown malignancies was reported across the studies, for a pooled estimate of 0.7%; more than 70% of these previously unknown malignancies were lung cancers. Extracardiac findings on cardiac CT require careful evaluation and reporting.