Computed Tomography Pulmonary Angiography In Patients Research Articles

Avoidable Overuse of Computed Tomography Pulmonary Angiography (CTPA) in Patients with Suspected Acute Pulmonary Thromboembolism (PTE): The Role of Clinical Prediction Rules and D-Dimer Assay

Background: Computed tomography pulmonary angiography (CTPA) is an imaging technique widely used in the diagnosis of acute pulmonary thromboembolism (PTE). Despite its disadvantages and potential risks, the overuse of CTPA has been a growing concern over the past decades. Objectives: The objective of this study was to investigate the rate of avoidable overuse of CTPA in patients with suspected PTE and to identify factors contributing to this overuse. The study aimed to highlight the importance of proper training for physicians in using validated diagnostic algorithms to minimize the overuse of CTPA and improve patient outcomes. Methods: In a cross-sectional study conducted between April 2016 and March 2019 at Shariati Hospital at Tehran University of Medical Sciences (TUMS), 1058 patients underwent CTPA due to suspected PTE. Wells scores were calculated retrospectively for all patients. The study defined avoidable overuse of CTPA as an imaging request without prior D-dimer testing or ignoring a negative D-dimer result in patients with low clinical pre-test probability. Results: Two hundred and seventy-three patients were excluded from the study due to unavailable documentation or pregnancy. Among the included 785 patients, 139 (17.7%) revealed PTE on CTPA. Based on the Wells scores, 480 patients were identified as the “PTE-unlikely” group. In this group, 299 patients (62.3%) underwent CTPA directly despite recommendations to order a D-dimer test first. Of these patients, 281 (94%) cases showed negative results. Moreover, CTPA was performed inappropriately in 52 “PTE-unlikely” cases despite negative D-dimer serum levels, and only one patient was diagnosed with PTE. Conclusions: The study revealed that 44.7% of the CTPA requests for patients with suspected PTE were avoidable, indicating the need for better adherence to current diagnostic guidelines to reduce unnecessary radiologic investigations and improve patient care.

Three-Dimensional Reconstruction Algorithm for CT Pulmonary Angiography in Patients with Pulmonary Embolism Combined with Syncope

This paper aimed to study the clinical characteristics of patients with pulmonary embolism (PE) with syncope (PE + S) based on the three-dimensional (3D) reconstruction algorithm in computed tomography (CT) pulmonary angiography (CTPA). In this study, 857 patients with acute PE (APE) who were treated in hospital were selected as the research objects and divided into syncope group (group S) and nonsyncope group (group NS). The 3D reconstruction marching cubes (3DR-MC) algorithm was compared with the traditional MC (T-MC) algorithm and the mesh simplification MC (MMS-MC) algorithm, and the results proved that the running time of the 3DR-MC algorithm on the platform was shorter than that of the other two algorithms. The incidence of syncope in group S in women was higher than that in group NS (51.7% vs. 38.2%). The incidence of syncope classified as high risk in group S was higher than that in group NS, and the mortality rate of pulmonary embolism patients with syncope was higher, and the difference was statistically significant (χ2 = 113.332, P < 0.05 ). The incidence of syncope in group S was higher than that in group NS (χ2 = 4.074, P < 0.05 ). In short, hypertension was an independent risk factor for syncope. PE + S patients could be diagnosed and treated as early as possible based on the clinical characteristics, so as to reduce the adverse consequences of misdiagnosis.

Pulmonary Embolism in COVID-19 Patients: A Retrospective Case-Control Study.

Background: Coagulopathy is a well-recognized complication in patients with coronavirus disease 2019 (COVID-19). Pulmonary embolism (PE) has substantial morbidity and mortality if the diagnosis is missed or the management is delayed. Computed tomography pulmonary angiography (CT-PA) is the imaging modality of choice for PE. Therefore, this study aimed to investigate the positive rate of CT-PA for PE among patients with COVID-19.Methods: We conducted a retrospective study examining the diagnostic yield of CT-PA in patients with confirmed COVID-19 and compared it with that in patients without COVID-19. The study included all adult patients with confirmed COVID-19 who presented from June 2020 to June 2021.Results: The study included 316 patients, including 158 patients with COVID-19, who underwent CT-PA for ruling out PE. Overall, 76 patients were found to have PE on the CT-PA scan, yielding a positive rate of 24.1%, with a significant difference between patients with COVID-19 (8.2%) and those without COVID-19 (39.9%). Further, 138 (87.3%) patients with COVID-19 had elevated D-dimer levels compared with 34 (21.5%) patients without COVID-19. A multivariable regression analysis model revealed that the smoking status (odds ratio [OR] = 1.94; 95% confidence interval [CI]: 1.4-3.8) and obesity (OR = 4.1; 95% CI: 1.5-8.9) were independent predictors of PE among patients with COVID-19. However, the elevated D-dimer level was not significantly associated with PE among patients with COVID-19 (OR = 0.7; 95% CI: 0.4-1.8).Conclusion: The study found that the positive rate of CT-PA for PE was lower among patients with PE indicating probable overutilization of investigation in these patients. Additionally, patients with COVID-19 had a higher proportion of elevated D-dimer levels that may be a contributor to the increased investigation for PE. Lastly, patients with COVID-19 who were current smokers had a higher tendency of having PE.

Frequency of computed tomography abnormalities in patients with chronic thromboembolic pulmonary hypertension: a comparative study between lung perfusion scan and computed tomography pulmonary angiography.

IntroductionChronic thromboembolic pulmonary hypertension (CTEPH) is one of the leading causes of pulmonary hypertension. Diagnosis of CTEPH can be established using various imaging techniques, including ventilation-perfusion scintigraphy (VQ) and multidetector computed tomography pulmonary angiography (CTPA). The aim of this study was to determine the frequency of direct pulmonary vascular, parenchymal lung, and cardiac abnormalities on CTPA in patients with CTEPH and to compare the diagnostic accuracy of both VQ scan CTPA in detecting CTEPH.MethodsWe retrospectively included 54 patients who had been referred for pulmonary hypertension service (20 males, 34 females). All patients had VQ scan and CTPA within 15 days and underwent pulmonary artery endarterectomy (PEA) thereafter. VQ scans were reported according to modified PIOPED (Prospective Investigation of Pulmonary Embolism Diagnosis) criteria. CTPA was considered as diagnostic for CTEPH if it showed presence of thrombus, webs, stenosis, or perfusion lung abnormalities.ResultsThe mean age of the study population was 41±10 years. The mean pulmonary artery pressure was 53±13 mmHg. Fifty-three out of 54 patients in the study population had high probability VQ scan and one patient had intermediate probability. CTPA was suggestive of CTEPH in all patients. The most frequent CTPA findings in the central pulmonary arteries and peripheral arteries were presence of thrombotic materials, abnormal vessel tapering and abrupt vessels-cut off (76% vs 65%, 67% vs 48%, and 48% vs 22%), respectively. The mosaic lung perfusion was present in 78% of the patients, and various cardiac morphology abnormalities were present and most common was abnormal right to left ventricle ratio (69%).ConclusionOur findings indicate that both VQ scan and CTPA are highly sensitive for the detection of CTEPH confirmed by PEA. Most CTEPH patients had several pulmonary vascular, parenchymal lung and cardiac abnormalities. There was no sign with 100% sensitivity on CTPA for CTEPH detection.

Pulmonary embolism in patients with COVID-19 and value of D-dimer assessment: a meta-analysis.

PurposeTo investigate, in a meta-analysis, the frequency of pulmonary embolism (PE) in patients with COVID-19 and whether D-dimer assessment may be useful to select patients for computed tomography pulmonary angiography (CTPA).MethodsA systematic literature search was performed for original studies which reported the frequency of PE on CTPA in patients with COVID-19. The frequency of PE, the location of PE, and the standardized mean difference (SMD) of D-dimer levels between patients with and without PE were pooled by random effects models.ResultsSeventy-one studies were included. Pooled frequencies of PE in patients with COVID-19 at the emergency department (ED), general wards, and intensive care unit (ICU) were 17.9% (95% CI: 12.0–23.8%), 23.9% (95% CI: 15.2–32.7%), and 48.6% (95% CI: 41.0–56.1%), respectively. PE was more commonly located in peripheral than in main pulmonary arteries (pooled frequency of 65.3% [95% CI: 60.0–70.1%] vs. 32.9% [95% CI: 26.7–39.0%]; OR = 3.540 [95% CI: 2.308–5.431%]). Patients with PE had significantly higher D-dimer levels (pooled SMD of 1.096 [95% CI, 0.844–1.349]). D-dimer cutoff levels which have been used to identify patients with PE varied between 1000 and 4800 μg/L.ConclusionThe frequency of PE in patients with COVID-19 is highest in the ICU, followed by general wards and the ED. PE in COVID-19 is more commonly located in peripheral than in central pulmonary arteries, which suggests local thrombosis to play a major role. D-dimer assessment may help to select patients with COVID-19 for CTPA, using D-dimer cutoff levels of at least 1000 μg/L.Key Points• The frequency of PE in patients with COVID-19 is highest in the ICU, followed by general wards and the ED.• PE in COVID-19 is more commonly located in peripheral than in central pulmonary arteries.• D-dimer levels are significantly higher in patients with COVID-19 who have PE.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00330-021-08003-8.

Utilization of serum D-dimer assays prior to computed tomography pulmonary angiography scans in the diagnosis of pulmonary embolism among emergency department physicians: a retrospective observational study

BackgroundA variety of evidence-based algorithms and decision rules using D-Dimer testing have been proposed as instruments to allow physicians to safely rule out a pulmonary embolism (PE) in low-risk patients.ObjectiveTo describe the prevalence of D-Dimer utilization among emergency department (ED) physicians and its impact on positive yields and utilization rates of Computed Tomography Pulmonary Angiography (CTPA).MethodsData was collected on all CTPA studies ordered by ED physicians at three sites during a 2-year period. Using a chi-square test, we compared the diagnostic yield for those patients who had a D-Dimer prior to their CTPA and those who did not. Secondary analysis was done to examine the impact of D-Dimer testing prior to CTPA on individual physician diagnostic yield or utilization rate.ResultsA total of 2811 CTPAs were included in the analysis. Of these, 964 CTPAs (34.3%) were ordered without a D-Dimer, and 343 (18.7%) underwent a CTPA despite a negative D-Dimer. Those CTPAs preceded by a D-Dimer showed no significant difference in positive yields when compared to those ordered without a D-Dimer (9.9% versus 11.3%, p = 0.26). At the individual physician level, no statistically significant relationship was found between D-Dimer utilization and CTPA utilization rate or diagnostic yield.ConclusionThis study provides evidence of suboptimal adherence to guidelines in terms of D-Dimer screening prior to CTPA, and forgoing CTPAs in patients with negative D-Dimers. However, the lack of a positive impact of D-Dimer testing on either CTPA diagnostic yield or utilization rate is indicative of issues relating to the high false-positive rates associated with D-Dimer screening.

EFFECTS OF TEST-BOLUS AND LOW-DOSE SCAN ON CT PULMONARY ANGIOGRAPHY IMAGE QUALITY IN PATIENTS WITH DIFFERENT BODY MASS INDEXES.

This study aimed to investigate different methods of obtaining high-quality Computed Tomography pulmonary angiography (CTPA) images using low-dose scanning in patients with different body mass index (BMI) values. Sixty patients with suspected pulmonary embolism were grouped based on their BMI values (BMI < 25, designated N, and BMI ≥ 25, designated O) and were assigned to receive either test bolus (TB) or bolus tracking (BT) at conventional (C) or low (L) dose. The effective dose (ED) in the N-TB-L group was lower than in the group N-TB-C (0.56±0.05 vs. 3.78±1.16, p<0.001), with similar image quality (4.90±0.31 vs. 4.70±0.47, p=0.120). The ED in the O-TB-L group was lower than in the O-TB-C group (0.54±0.03 vs. 5.14±1.34, p<0.001), but the group O-TB-C's image quality was higher (4.65±0.59 vs. 3.95±0.89, p=0.006). Groups N-TB-L versus O-TB-L, groups N-TB-L versus N-BT-L and groups O-TB-C versus O-BT-C had similar EDs (all ps>0.05), but the image quality was different (all ps<0.05). In conclusion, the results showed that the image quality of low-dose CTPA scanning using TB was similar to that of the conventional-dose CTPA in patients with BMI < 25 but was lower in patients with BMI ≥ 25. TB was better than BT for all patients, regardless of BMI, when receiving the same ED.

Systemic thrombolysis and anticoagulation improved biomarker measurements in massive-like pulmonary embolism and severe COVID-19 pneumonia: a case report.

BackgroundFrom asymptomatic patients to severe acute respiratory distress syndrome, COVID-19 has a wide range of clinical presentations, and venous thromboembolism has emerged as a critical and frequent complication.Case summaryWe present a case of a 69-year-old man with a clinical presentation of massive-like pulmonary embolism (PE) overlapping with severe COVID-19 pneumonia. The diagnosis was made based on hypotension, severe oxygen desaturation (33%), and right ventricular dysfunction (RVD). We used alteplase and low-molecular-weight heparin, obtaining immediate clinical improvement. Also, we identified an extremely elevated D-dimer (31.2 mcg/mL), and computed tomography pulmonary angiography (CTPA) revealed an unexpected low thrombus burden and a crazy-paving pattern. Considering this, we decided to discontinue the alteplase. Therefore, the mechanisms of pulmonary hypertension and RVD could be multifactorial. Despite the patient’s respiratory status worsening and ongoing mechanical ventilation, biomarkers kept lowering to normal ranges. It appears a favourable outcome was related to early PE diagnosis and a multimodal therapeutic approach.DiscussionPhysicians in the ER should be warned about extremely high D-dimer measurements and severe oxygen desaturation as possible markers of severe COVID-19 pneumonia in patients with high-clinical suspicion of PE. Although ESC guidelines recommend immediate reperfusion in cardiogenic shock secondary to PE, we suggest initial CTPA in patients with high-clinical suspicion of severe COVID-19.

P1267 Negative baseline diagnostic imaging does not exclude pulmonary embolism in patients with reccurrent syncope

Abstract INTRODUCTION In patients who are admitted to a hospital due to episode of syncope, acute pulmonary embolism (PE) is rarely considered as a possible cause. This report presents two cases illustrating PE as a cause of syncope with elevated cardiac troponin (cTn) and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels despite normal echocardiographic examination and negative Doppler ultrasound imaging. Case 1: An 83-year-old woman admitted to the ER due to episodes of recurrent syncopes. According to her anamnesis, she had four episodes of syncopes during last three weeks without chest pain, dyspnea, palpitation or hemoptysis. ECG revealed a normal sinus rhythm with a heart rate of 70 bpm without ischemic changes. Laboratory tests revealed raised levels of cTn and NT-proBNP. Transthoracic echocardiography (TTE) demonstrated preserved left and right ventricular systolic functions without any cardiac chamber enlargement and mild tricuspid regurgitation with a PAP of 35 mmHg. Patient’s pre-test probability for pulmonary embolism was low (Wells’ score &amp;lt; 2) but D-dimer level was elevated. Doppler imaging for detection of deep vein thrombosis was negative. Computed tomography pulmonary angiography (CTPA) showed filling defects in the pulmonary arteries consistent with pulmonary embolism (Panel A). The patient was discharged with rivaroxaban therapy without any complication. Case 2: A 69- year-old woman presented to ER with symptoms of chest pain and recurrent episodes of syncope for the last 2 days. Her medical history revealed hypertension and hyperlipidemia. On admission ECG showed a normal sinus rhythm with a heart rate of 105 bpm and T-wave inversions in inferior leads. Laboratory tests showed elevated levels of cTn and NT-proBNP. TTE demonstrated normal left ventricular systolic function with an ejection fraction of 55% and normal right ventricular function and chamber size with a tricuspid annular plane systolic excursion of 22 mm. Diagnostic coronary angiography was performed to exclude acute ischemia revealed non-significant coronary artery stenosis. Doppler ultrasound imaging for detection of deep vein thrombosis was negative. CTPA showed filling defects in the bilateral main pulmonary arteries consistent with acute bilateral pulmonary embolism (Panel B-C). The patient was discharged with rivaroxaban therapy after four days of hospitalization period without any complication. CONCLUSION Elevated cTn and NT-proBNP leves on admission strongly suggest transient hemodynamic impairment causing cardiac injury and syncope. Normal admission ECG and TTE can exclude most possible acute cardiac causes of syncope. Although acute right ventricular dsyfunction is the most frequent finding of acute massive PE causing hemodymanic impairment resulting with syncope, diagnosis of acute PE should only be excluded with CTPA in patients with similar clinical characteristics despite normal TTE and negative venous Doppler ultrasound imaging. Abstract P1267 Figure

Prevalence of Non-Thromboembolic Incidental Findings on Computed Tomography-Pulmonary Angiography for Pulmonary

Introduction: Computed Tomography-Pulmonary Angiography (CTPA) is a noninvasive imaging modality for direct diagnosis of pulmonary thromboembolism. The potential advantage of CTPA is possible alternative and incidental findings in cases that PTE is ruled out. This study was performed to determine the prevalence of incidental findings in CTPA in patients suspected to have PTE. Methods: This cross-sectional retrospective study was performed in patients with suspected PTE admitted to Shohada-e-Tajrish Hospital in 2014 and 2015 and underwent CTPA for final diagnosis. Incidental findings in CTPA and associated clinical symptoms were assessed. Results: According to CTPA performed in 188 patients, PTE was diagnosed in 61 cases (32.4%). Prevalence of incidental abnormal findings in the two groups with and without PTE were 93.7% and 90.9%, respectively. The most common incidental finding was pleural effusion (42%). There was no significant association between clinical symptoms and incidental findings in CTPA in patients with suspected pulmonary embolism (P > 0.05). The only significant finding was association between lung mass and tachypnea (P=0.007). Conclusion: In patients with primary clinical symptoms of suspected pulmonary embolism, in most cases there was a wide range of incidental findings and simultaneous pathologies in CTPA mimicking the primary symptoms of pulmonary embolism. However, in this study there was no significant association between clinical symptoms and incidental findings. Determination of definite indications of CTPA in patients with suspected pulmonary embolism is necessary.

Rethinking Intravenous Catheter Size and Location for Computed Tomography Pulmonary Angiography.

IntroductionComputed tomography pulmonary angiography (CTPA) is the test of choice for diagnosis of pulmonary embolism (PE) in the emergency department (ED), but this test may be indeterminate for technical reasons such as inadequate contrast filling of the pulmonary arteries. Many hospitals have requirements for intravenous (IV) catheter size or location for CTPA studies to reduce the chances of inadequate filling, but there is a lack of clinical data to support these requirements. The objective of this study was to determine if a certain size or location of IV catheter used for contrast for CTPA is associated with an increased chance of suboptimal CTPA.MethodsThis was a retrospective chart review of patients who underwent CTPA in the ED. A CTPA study was considered suboptimal if the radiology report indicated it was technically limited or inadequate to exclude a PE. The reason for the study being suboptimal, and the size and location of the IV catheter, were abstracted. We calculated the rate of inadequate contrast filling of the pulmonary vasculature and compared the rate for various IV catheter sizes and locations. In particular, we compared 20-gauge or larger IV catheters in the antecubital fossa or forearm to all other sizes and locations.ResultsA total of 19.3% of the 1500 CTPA reports reviewed met our criteria as suboptimal, and 51.6% of those were due to inadequate filling. Patients with a 20-gauge IV catheter or larger placed in the antecubital fossa or forearm had inadequate filling 9.2% of the time compared to 13.2% for patients who had smaller IVs or IVs in other locations (difference: 4.0% [95% confidence interval, −1.7%–9.7%]). There were also no statistically significant differences in the rates of inadequate filling when data were further stratified by IV catheter location and size.ConclusionWe did not detect any statistically significant differences in the rate of inadequate contrast filling based on IV catheter locations or sizes. While small differences not detected in this study may exist, it seems prudent to proceed with CTPA in patients with difficult IV access who need emergent imaging even if they have a small or distally located IV.

Randomised trial of no hydration vs. sodium bicarbonate hydration in patients with chronic kidney disease undergoing acute computed tomography–pulmonary angiography

Hydration to prevent contrast-induced acute kidney injury (CI-AKI) induces a diagnostic delay when performing computed tomography-pulmonary angiography (CTPA) in patients suspected of having acute pulmonary embolism. To analyze whether withholding hydration is non-inferior to sodium bicarbonate hydration before CTPA in patients with chronic kidney disease (CKD). We performed an open-label multicenter randomized trial between 2009 and 2013. One hundred thirty-nine CKD patients were randomized, of whom 138 were included in the intention-to-treat population: 67 were randomized to withholding hydration and 71 were randomized to 1-h 250mL 1.4% sodium bicarbonate hydration before CTPA. Primary outcome was the increase in serum creatinine 48-96h after CTPA. Secondary outcomes were the incidence of CI-AKI (creatinine increase >25%/>0.5mgdL(-1) ), recovery of renal function, and the need for dialysis within 2months after CTPA. Withholding hydration was considered non-inferior if the mean relative creatinine increase was ≤15% compared with sodium bicarbonate. Mean relative creatinine increase was -0.14% (interquartile range -15.1% to 12.0%) for withholding hydration and -0.32% (interquartile range -9.7% to 10.1%) for sodium bicarbonate (mean difference 0.19%, 95% confidence interval -5.88% to 6.25%, P-value non-inferiority <0.001). CI-AKI occurred in 11 patients (8.1%): 6 (9.2%) were randomized to withholding hydration and 5 (7.1%) to sodium bicarbonate (relative risk 1.29, 95% confidence interval 0.41-4.03). Renal function recovered in 80.0% of CI-AKI patients within each group (relative risk 1.00, 95% confidence interval 0.54-1.86). None of the CI-AKI patients developed a need for dialysis. Our results suggest that preventive hydration could be safely withheld in CKD patients undergoing CTPA for suspected acute pulmonary embolism. This will facilitate management of these patients and prevents delay in diagnosis as well as unnecessary start of anticoagulant treatment while receiving volume expansion.

Imaging diagnosis of acute pulmonary embolism

Pulmonary embolism represents a major public healthcare problem and it also imposes frequent clinical diagnostic issues. Despite the availability of the D-dimer tests, imaging remains the mainstay for its diagnosis. Computed tomography pulmonary angiography (CTPA) is now the most widely used diagnostic test and its utility has been well validated in a large number of trials. Nuclear medicine techniques, which are also well established, are now used significantly less frequently. Magnetic resonance pulmonary angiography is developing as an alternative to CTPA in patients who have contraindications to iodinated contrast media. Catheter pulmonary angiography remains the gold standard, although it is being used increasingly less frequently. In this article, we review the current knowledge on the imaging diagnosis of acute pulmonary embolism with special emphasis on the noninvasive techniques.