The rehabilitation of clinical assessment for the diagnosis of pulmonary embolism

Pulmonary angiography is the gold standard for diagnosis of segmental pulmonary embolism, but no longer for subsegmental pulmonary embolism because the inter-observer agreement for angiographically documented subsegmental pulmonary embolism is only 60%. A normal rapid ELISA VIDAS D-dimer test result and a normal perfusion scan exclude pulmonary embolism with a negative predictive value of >99%, irrespective of clinical score. The positive predictive value for pulmonary embolism of a high probability VP-scan compared to pulmonary angiography is 87% indicating that 13% of patients with a high probability VP-scan do not have pulmonary embolism. The combination of a negative CUS, a low clinical score, and a non-diagnostic VP-scan safely excludes pulmonary embolism. Patients with a non-diagnostic VP-scan, a negative CUS, but a moderate to high clinical score are candidates for pulmonary angiography. The positive predictive value of helical spiral CT is >95 to 99%. The combination of a negative CUS, a low clinical score, and the presence of a clear alternative diagnosis is predicted to safely exclude pulmonary embolism. Helical spiral CT detects all clinical relevant pulmonary emboli and a large number of alternative diagnoses in symptomatic patients with a non-diagnostic or a high-probability VP-scan. The negative predictive value during 3 months followup after a negative spiral CT for pulmonary embolism in 4 retrospective studies and 1 prospective management study was >99%. Only a small group of patients (1-2%) with a non-diagnostic spiral CT are candidates for pulmonary angiography. Therefore, it is predicted that the spiral CT will replace both VP-scanning and pulmonary angiography to safely exclude or diagnose pulmonary emboli in patients with suspected pulmonary embolism.     

D-二聚体在肺栓塞诊断中的作用研究

目的 研究D-二聚体在诊断肺栓塞中的作用。方法 对80例临床可疑肺栓塞的患者进行回顾性分析，病人均行血D-二聚体测定和肺灌注扫描，通过肺扫描分为正常组、高可能性组和非诊断组，非诊断组再经肺动脉造影确定诊断。血D-二聚体测定采用乳胶凝集法。结果 共检出肺栓塞阳性41例，阴性39例，检出率51．2％。D-二聚体的敏感性和特异性分别为58．5％、51．3％，阳性预测值和阴性预测值分别为55．8％、54．5％。结论 D-二聚体测定尚不宜作为肺栓塞的筛选指标。     

Non-invasive exclusion and diagnosis of pulmonary embolism by sequential use of the rapid ELISA D-dimer assay, clinical score and spiral CT.

Pulmonary angiography is the gold standard for segmental pulmonary embolism (PE) but no longer for its subsegmental PE, because the inter-observer agreement for angiographically documented subsegmental PE is only 60%. Two non-invasive tools exclude PE with a negative predictive value of > 99%: a normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test. The positive predictive value of a high probability ventilation-perfusion lung scan (VP-scan) is only 85% to 87%. The combination of a low clinical score and a non-diagnostic VP-scan safely exclude PE without the need of angiography. The prevalence of PE and that of an alternative diagnosis in symptomatic patients with a non-diagnostic VP-scan are 10% to 20% and 30% to 45%, respectively. Helical spiral computed tomography (CT) detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with a non-diagnostic or high probability VP-scan. The positive predictive value of the spiral CT is > 95%. Single-slice helical CT as the primary diagnostic test in patients with suspected PE in retrospective outcome studies and in prospective multicenter management studies indicate that the negative predictive value of a negative spiral CT preceded or followed by a negative compression ultrasonography (CUS) is > 99%. Therefore, a helical spiral CT can replace both the VP-scan and pulmonary angiography to safely rule in and out PE. A negative rapid ELISA VIDAS D-dimer test result will reduce the need for helical spiral CT by 25% to 35%.     

Clinical outcomes in patients with suspected acute pulmonary embolism and negative helical computed tomographic results in whom anticoagulation was withheld

BACKGROUND: Helical computed tomography (CT) techniques for the diagnosis of pulmonary embolism have been refined over the past decade. Helical CT is widely used in the diagnosis of pulmonary embolism despite the lack of well-designed trials supporting this approach. Although helical CT correlates well with pulmonary angiography in detecting central emboli, critics argue that it misses more distal embolic events. It is unknown, however, whether distal emboli are clinically significant. If undetected distal emboli are significant, we reasoned that venous thromboembolic events should occur more often in patients with negative helical CT results who were not receiving anticoagulation. METHODS: We performed a retrospective analysis of 433 sequential helical CT scans ordered for clinical suspicion of pulmonary embolism from March 9, 1999, until April 30, 2002. We excluded 119 studies (27%) that were positive for pulmonary embolism, then excluded 57 others of patients who had received anticoagulation throughout the study period. We then contacted patients and families, and reviewed hospital records and death summaries to determine whether the patients had developed any venous thromboembolic events during the 3-month period following their negative helical CT. RESULTS: Follow-up was completed on 239 (98.4%) of 243 patients. Venous thromboembolic events developed in 4 (1.7%; 95% confidence interval, 0.0%-3.2%). In the 3-month follow-up period, 33 patients died, 1 of a probable pulmonary embolism (0.4% of the study group; 95% confidence interval, 0.0%-1.2%). CONCLUSIONS: Our data support helical CT as a safe, definitive, minimally invasive test that is associated with a low 3-month risk of venous thromboembolism, and may be comparable to results of negative pulmonary angiography or low-probabililty ventilation-perfusion scan.     

Performance of helical computed tomography in unselected outpatients with suspected pulmonary embolism.

BACKGROUND: Helical computed tomography (CT) is commonly used to diagnose pulmonary embolism, although its operating characteristics have been insufficiently evaluated. OBJECTIVE: To assess the sensitivity and specificity of helical CT in suspected pulmonary embolism. DESIGN: Observational study. SETTING: Emergency department of a teaching and community hospital. PATIENTS: 299 patients with clinically suspected pulmonary embolism and a plasma D -dimer level greater than 500 microgram/L. INTERVENTION: Pulmonary embolism was established by using a validated algorithm that included clinical assessment, lower-limb compression ultrasonography, lung scanning, and pulmonary angiography. MEASUREMENTS: Sensitivity, specificity, and likelihood ratios of helical CT and interobserver agreement. Helical CT scans were withheld from clinicians and were read 3 months after acquisition by radiologists blinded to all clinical data. RESULTS: 118 patients (39%) had pulmonary embolism. In 12 patients (4%), 2 of whom had pulmonary embolism, results of helical CT were inconclusive. For patients with conclusive results, sensitivity of helical CT was 70% (95% CI, 62% to 78%) and specificity was 91% (CI, 86% to 95%). Interobserver agreement was high (kappa = 0.823 to 0.902). The false-negative rate was lower for helical CT used after initial negative results on ultrasonography than for helical CT alone (21% vs. 30%). Use of helical CT after normal results on initial ultrasonography and nondiagnostic results on lung scanning had a false-negative rate of only 5% and a false-positive rate of only 7%. CONCLUSION: Helical CT should not be used alone for suspected pulmonary embolism but could replace angiography in combined strategies that include ultrasonography and lung scanning.     

Clinical utility of D-dimer in patients with suspected pulmonary embolism and nondiagnostic lung scans or negative CT findings

BACKGROUND: The diagnosis of pulmonary embolism is difficult because the clinical diagnosis is nonspecific and all of the objective tests have limitations. The assay for plasma d-dimer may be useful as an exclusion test if results are negative. We conducted a prospective cohort study that evaluated the clinical utility (usefulness) of an automated quantitative d-dimer test in the diagnosis of patients with suspected pulmonary embolism. METHODS: Consecutive eligible patients who had clinically suspected PE with nondiagnostic lung scans or negative helical CT scan of the chest results underwent d-dimer testing. RESULTS: The d-dimer results were negative in 11 of 103 inpatients (10.6%, 95% confidence interval [CI], 5.5 to 18.3%) and 7 of 22 outpatients (31.8%, 95% CI, 13.9 to 54.9%; p = 0.02). CONCLUSIONS: Measurement of plasma d-dimer is of limited clinical utility for inpatients with clinically suspected pulmonary embolism and nondiagnostic lung scans or negative helical CT results at a US academic health center.     

Spiral CT for pulmonary embolism

Radiologic imaging for pulmonary embolism has been problematic. Ventilation perfusion scanning is frequently inconclusive; pulmonary angiography has been traditionally underused. Now spiral computed tomographic (CT) angiography provides a readily available, noninvasive test for pulmonary embolism. The accuracy of this examination is exceedingly high, so it should become the first-line test for pulmonary embolism. Recent investigations reveal a high negative predictive value for spiral CT, further proving its value. In addition, spiral CT provides an alternative diagnosis in a high percentage of patients. This article reviews current literature regarding the sensitivity, specificity, reliability, consistency, and cost-effectiveness of spiral CT.     

Clinical validity of negative helical computed tomography for clinical suspicion of pulmonary embolism

BACKGROUND: Helical computed tomography has been introduced for the diagnosis of pulmonary embolism. OBJECTIVE: To determine the clinical safety of withholding anticoagulant treatment in patients with suspicion of pulmonary embolism and negative helical computed tomography study. METHODS: During a 9-month period, we performed a prospective study including 209 consecutive patients who underwent helical computed tomography for clinical suspicion of pulmonary embolism. In 53 patients (25.5%), helical computed tomography was diagnostic for pulmonary embolism, and in 24 patients (11.5%) it was indeterminate. In 132 patients (63%), the examination was negative for pulmonary embolism and no anticoagulation treatment was given. A clinical 3-month follow-up was carried out. During this period, 29 patients (22%) were excluded because anticoagulation therapy was initiated for other reasons, or because other diagnostic techniques were performed for pulmonary embolism. Four patients were lost in the 3-month period. In the end, 99 patients (75%) were included in the clinical follow-up. RESULTS: Out of the 99 patients, 9 (9%) died during the 9-month follow-up, the cause of death in each case was not due to thromboembolic venous disease. No venous thromboembolic events were detected in the other 90 patients. Negative predictive value of helical computed tomography for pulmonary embolism was 99.09% (95% CI, 95.03-99.97%). CONCLUSIONS: In patients with clinical suspicion of pulmonary embolism and initial negative helical computed tomography from whom anticoagulants are withheld, no thromboembolic disease was detected in a 3-month follow-up. We consider helical computed tomography an effective method for ruling out pulmonary embolism as well as a front-line tool for diagnosis.     

Normal D-dimer levels in emergency department patients suspected of acute pulmonary embolism

OBJECTIVES: We sought to determine:1) whether normal D-dimer enzyme-linked immunosorbent assay (ELISA) assays predicted the absence of pulmonary embolism (PE) in the high-volume emergency department (ED) of the Brigham and Women's Hospital, and 2) whether ED physicians accepted normal D-dimer levels as confirmation of no PE without further diagnostic testing such as lung scanning, chest computed tomography (CT) scanning, or pulmonary angiography. BACKGROUND: Although the plasma D-dimer ELISA is a sensitive screening test for excluding acute PE, this laboratory marker has not been widely integrated into clinical algorithms such as creatine kinase-MB fraction or troponin testing for acute myocardial infarction. METHODS: We mandated that ED physicians order D-dimer ELISA tests on all patients suspected of acute PE. We reviewed the clinical record of each ED patient initially evaluated for suspected PE during the year 2000. We determined whether additional imaging tests for PE were obtained and whether the final diagnosis was PE. RESULTS: Of 1,106 D-dimer assays, 559 were elevated and 547 were normal. Only 2 of 547 had PE despite a normal D-dimer. The sensitivity of the D-dimer ELISA for acute PE was 96.4% (95% confidence interval [CI]: 87.5% to 99.6%), and the negative predictive value was 99.6% (95% CI: 98.7% to >99.9%). Nevertheless, 24% of patients with normal D-dimers had additional imaging tests for PE. CONCLUSIONS: The D-dimer ELISA has a high negative predictive value for excluding PE. By paying more attention to normal D-dimer results, fewer chest CT scans and lung scans will be required, and improvements may be realized in diagnostic efficiency and cost reduction.     

Strategies incorporating spiral CT for the diagnosis of acute pulmonary embolism: a cost-effectiveness analysis

OBJECTIVE: To assess the cost-effectiveness of spiral CT for the diagnosis of acute pulmonary embolism. DESIGN: Computer-based cost-effectiveness analysis. PATIENTS: Simulated cohort of 1,000 patients with suspected acute pulmonary embolism (PE), with a prevalence of 28.4%, as in the Prospective Investigation of Pulmonary Embolism Diagnosis study. INTERVENTIONS: Using a decision-analysis model, seven diagnostic strategies were compared, which incorporated combinations of ventilation-perfusion (V/Q) scans, duplex ultrasound of the legs, spiral CT, and conventional pulmonary angiography. MEASUREMENTS AND RESULTS: Expected survival and cost (in Canadian dollars) at 3 months were estimated. Four of the strategies yielded poorer survival at higher cost. The three remaining strategies were as follows: (1) V/Q +/- leg ultrasound +/- spiral CT, with an expected survival of 953.4 per 1,000 patients and a cost of $1,391 per patient; (2) V/Q +/- leg ultrasound +/- pulmonary angiography (the "traditional" algorithm), with an expected survival of 953.7 per 1,000 patients and a cost of $1,416 per patient; and (3) spiral CT +/- leg ultrasound, with an expected survival of 958.2 per 1,000 patients and a cost of $1,751 per patient. The traditional algorithm was then excluded by extended dominance. The cost per additional life saved was $70,833 for spiral CT +/- leg ultrasound relative to V/Q +/- leg ultrasound +/- spiral CT. CONCLUSIONS: Spiral CT can replace pulmonary angiography in patients with nondiagnostic V/Q scan and negative leg ultrasound findings. This approach is likely as effective as-and possibly less expensive than-the current algorithm for diagnosis of acute PE. When spiral CT is the initial diagnostic test, followed by leg ultrasound, expected survival improves but costs are also considerably higher. These findings were robust to variations in the assumed sensitivity and specificity of spiral CT.     

64排螺旋CT冠脉成像与冠脉造影对冠心病诊断的比较

目的：探讨64排螺旋CT冠脉成像对冠心病的诊断价值。方法：以冠脉造影（CAG）结果为金指标，采用64排螺旋CT对100例疑诊冠心病患者的冠脉主干及主要分支400节段进行重建和分析，评价其诊断冠心病的灵敏性和特异性。结果：64排螺旋CT能清晰显示冠脉主干及分支狭窄、钙化、开口起源异常及桥血管病变，对冠脉狭窄性病变的诊断准确性高，诊断冠脉病变的灵敏度96.37％，特异度96．14％，阳性预测值95．88％，阴性预测值96．6％。但对慢性闭塞性病变诊断性的准确率稍差，灵敏度50％，特异度96．77％，阳性预测值62．5％，阴性预测值94．73％。结论：64排螺旋CT冠脉成像对冠脉狭窄病变、桥血管、心肌桥、支架管腔均显影良好，对钙化病变诊断率优于冠脉造影，可以作为冠心病高危人群无创性筛选检查及冠脉支架、搭桥术后随访手段。     

Multidetector computed tomography for the diagnosis of acute pulmonary embolism

PURPOSE OF REVIEW: This review describes the accuracy of multidetector contrast-enhanced computed tomography (CT) for the diagnosis of acute pulmonary embolism, the role of clinical assessment and of venous phase imaging in combination with it, and the approach to the diagnosis. RECENT FINDINGS: The sensitivity of CT angiography was 83%, specificity 96% and positive predictive value 86%. Positive predictive values were 97% for pulmonary embolism in a main or lobar artery, 68% for a segmental vessel, and 25% for a subsegmental branch. A CT angiogram with concordant clinical probability assessment resulted in high predictive values, but with a discordant clinical probability, predictive value was low. The sensitivity for pulmonary embolism increased to 90% by using CT venography in combination with CT angiography.A negative D-dimer by the rapid enzyme-linked immunosorbent assay method with a low or moderate probability clinical assessment can safely exclude pulmonary embolism. Clinical probability assessment and D-dimer are recommended. In general, CT angiography in combination with CT venography is recommended, but the choice of diagnostic tests depends on the clinical situation. SUMMARY: The reliability of multislice CT angiography is enhanced by clinical assessment and CT venography used with it. Clinical assessment and D-dimer are recommended before imaging.     

Value of the association of D-dimer measurement and the evaluation of clinical probability in a non-invasive diagnostic strategy of pulmonary embolism

New diagnostic tools in suspected pulmonary embolism complete the classical diagnostic strategy of pulmonary scintigraphy and pulmonary angiography to limit the indications of these two invasive investigations. In a prospective series of 204 consecutive patients with suspected pulmonary embolism the association of D-dimer measurement and clinical probability was assessed for the exclusion of the diagnosis of pulmonary embolism. The D-DI Liatest is a new generation, unitary, rapid and quantitative latex test with a comparative diagnostic performance to that of the reference ELISA test, and well adapted to emergency situations.The clinical probability was assessed by a quantitative score based on past history, clinical symptoms and signs. The positive diagnosis of pulmonary embolism was made by spiral CT scanner and/or pulmonary angiography, associated with Duplex ultrasonography of the leg veins in nondiagnostic results. The prevalence of pulmonary embolism was 42.6% and the absence of anticoagulation in patients considered not to have pulmonary embolism was associated with a thrombo-embolic incidence of 0.9% at 3 months. Fifty-six patients had D-dimer concentrations equal or inferior to the threshold of 500 microg/L; the sensitivity was 99% and the specificity 47% with a negative predictive value of 98% to 100% in cases with a low clinical probability. D-dimer measurement is reliable and has a high cost-benefit value in ambulatory patients with suspected of pulmonary embolism and is even more valuable when the clinical probability of this diagnosis is low.     

Computer-aided detection of pulmonary embolism on CT angiography: initial experience

OBJECTIVE: To evaluate the performance of a computer-aided detection (CAD) system for diagnosis of pulmonary embolism on computed tomography (CT) pulmonary angiography. MATERIALS AND METHODS: One hundred and four pulmonary CT angiograms for pulmonary emboli (PE) were reviewed both by radiologists and a CAD detection system (ImageChecker CT V2.0, R2 Technology Inc, Sunnyvale, CA). CT scans, read and reported by radiologists in a routine daily clinical setting, were later processed by the CAD system. The performance of the CAD system was analyzed. RESULTS: Forty-five PE were identified by the radiologists in 15 patients. The CAD system revealed 123 findings, interpreted by the system as PE. Twenty-six of them, detected in 8 patients, represented true-positive results. Ninety-seven (78.9%) CAD findings were not true PE and were defined as false-positive. Nineteen true PE in 7 patients were missed by the CAD system constituting 42% false-negative rate. Sensitivity of the CAD system was 53.3% and the specificity was 77.5%. The positive predictive value of CAD system was 28.5% and the negative predictive value was 90.7%. CONCLUSIONS: With the evaluated CAD system, it is relatively simple and fast to check all detected findings and decide if they represent true PE. However, high false-negative results demand technologic improvement, to increase the sensitivity of the system. It is anticipated to become a promising supplement to the work and eyes of the radiologist in detecting PE on pulmonary CT angiography.     

多层螺旋CT血管成像技术在肺动脉栓塞中的应用价值

目的探讨多层螺旋CT血管成像技术在肺动脉栓塞中的应用价值。方法回顾分析11例被证实的在肺动脉栓塞患者,行血管造影（CTA）检查,后处理采用多平面重建（MPR）、曲面重建（CPR）、最大密度投影（MIP）及容积重建（VR）等多种后处理技术。结果肺动脉增强后的CT值显著高于栓子的CT值,同时,CT横断面图像结合多平面重建、曲面重建、最大密度投影和容积重建等处理清晰地显示了肺动脉栓塞的部位和栓子形态。结论利用多层螺旋CT血管成像技术可以清晰显示肺动脉的栓塞部位和血栓栓子的形态,对肺栓塞的诊断具有明显的技术优势和较高的临床价值。     

64层螺旋CT对老年冠状动脉疾病患者的诊断价值评价

目的探讨64层螺旋CT对老年冠状动脉疾病患者的诊断价值。方法对61例疑为冠心病的老年患者进行冠状动脉64层螺旋CT扫描,并于1周之内进行冠状动脉造影检查。以冠状动脉造影为“金标准”,评价冠状动脉64层螺旋CT诊断老年冠状动脉疾病患者的敏感性、特异性、阳性预测值、阴性预测值及准确度。结果61例患者总计915个冠状动脉节段,64层螺旋CT能够评价其中882个节段(96．4％),其检测中度以上冠状动脉狭窄的敏感性75．6％,特异性88．1％,阳性预测值64．0％,阴性预测值92．8％,准确度85．4％。结论64层螺旋CT对老年冠状动脉疾病患者具有较高的诊断价值,有可能成为筛查老年人冠心病的一个较为可靠的无创检测手段     

16层螺旋CT冠状动脉成像在冠心病诊断中的应用研究

目的评价16层螺旋CT冠状动脉成像的临床应用价值,探讨提高冠状动脉成像质量的方法。方法40例患者行16层螺旋CT冠状动脉成像,选取图像质量较佳的22例患者,进行选择性冠状动脉造影检查,将两者结果对照分析。结果88支冠状动脉,多层螺旋CT冠状动脉成像(MSCTCA)诊断冠状动脉狭窄的敏感性为86.80%,特异性为86.20%,阳性预测率为76.47%,阴性预测率92.59%,假阳性率13.70%,假阴性率13.30%。对诊断有临床意义的冠状动脉狭窄的敏感性为90.0%,特异性为70.0%,阳性预测率为60.0%,阴性预测率93.3%,假阳性率30.0%,假阴性率10.0%。两者对冠状动脉狭窄诊断差异无统计学意义。结论16层螺旋CT冠状动脉成像技术是一项可靠的冠心病诊断方法,作为一项非创伤性技术,是评价冠状动脉狭窄病变的重要筛选手段。     

Diagnosis of subsegmental pulmonary emboli: a multi-center study using a porcine model

We measured sensitivity, positive predictive value, and free-response receiver operating characteristic (FROC) of 20 radiologists detecting subsegmental-sized pulmonary emboli in a porcine model using either contrast-enhanced computed tomography (CT) or digital subtraction (DS) pulmonary angiography. Colored methacrylate beads (4.2 and 3.8 mm diameter) were injected into 9 anesthetized juvenile pigs. CT and DS pulmonary angiography images were obtained before and after a pulmonary infiltrate was introduced into the lower lobes. Following imaging, the pigs were euthanized, and the pulmonary arterial tree was cast using clear methacrylate allowing direct visualization of emboli. The 20 radiologists used a custom-made computer application to display the images on their personal computer and record their diagnoses. The results were mailed electronically to the coordinating center for comparison with the cast of the pulmonary vasculature. Twenty-three emboli were included in the statistical analysis. Overall sensitivity for spiral CT and angiography, respectively, was: 60 +/- 18% and 72 +/- 11% (P = 0.06). Positive predictive value for spiral CT and angiography, respectively, was: 49 +/- 24% and 58 +/- 23% (P = 0.25). There was a large variation in both sensitivity and positive predicted values between Readers. There was no difference in sensitivity or positive predictive value between radiologists from community or academic centers (P > 0.27). FROC analysis showed no significant difference between CT or DS (P = 0.27). In conclusion, in this porcine model, there is no overall diagnostic advantage to using DS pulmonary angiography rather than contrast-enhanced spiral CT for the diagnosis of PE when images are interpreted by radiologists located in either academic or community hospital settings.     

Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer.

BACKGROUND: The limitations of the current diagnostic standard, ventilation-perfusion lung scanning, complicate the management of patients with suspected pulmonary embolism. We previously demonstrated that determining the pretest probability can assist with management and that the high negative predictive value of certain D -dimer assays may simplify the diagnostic process. OBJECTIVE: To determine the safety of using a simple clinical model combined with D -dimer assay to manage patients presenting to the emergency department with suspected pulmonary embolism. DESIGN: Prospective cohort study. SETTING: Emergency departments at four tertiary care hospitals in Canada. PATIENTS: 930 consecutive patients with suspected pulmonary embolism. INTERVENTIONS: Physicians first used a clinical model to determine patients' pretest probability of pulmonary embolism and then performed a D -dimer test. Patients with low pretest probability and a negative D -dimer result had no further tests and were considered to have a diagnosis of pulmonary embolism excluded. All other patients underwent ventilation-perfusion lung scanning. If the scan was nondiagnostic, bilateral deep venous ultrasonography was done. Whether further testing (by serial ultrasonography or angiography) was done depended on the patients' pretest probability and the lung scanning results. MEASUREMENTS: Patients received a diagnosis of pulmonary embolism if they had a high-probability ventilation-perfusion scan, an abnormal result on ultrasonography or pulmonary angiography, or a venous thromboembolic event during follow-up. Patients for whom the diagnosis was considered excluded were followed up for 3 months for the development of thromboembolic events. RESULTS: The pretest probability of pulmonary embolism was low, moderate, and high in 527, 339, and 64 patients (1.3%, 16.2%, and 37.5% had pulmonary embolism), respectively. Of 849 patients in whom a diagnosis of pulmonary-embolism had initially been excluded, 5 (0.6% [95% CI, 0.2% to 1.4%]) developed pulmonary embolism or deep venous thrombosis during follow-up. However, 4 of these patients had not undergone the proper diagnostic testing protocol. In 7 of the patients who received a diagnosis of pulmonary embolism, the physician had performed more diagnostic tests than were called for by the algorithm. In 759 of the 849 patients in whom pulmonary embolism was not found on initial evaluation, the diagnostic protocol was followed correctly. Only 1 (0.1% [CI, 0.0% to 0.7%]) of these 759 patients developed thromboembolic events during follow-up. Of the 437 patients with a negative D -dimer result and low clinical probability, only 1 developed pulmonary embolism during follow-up; thus, the negative predictive value for the combined strategy of using the clinical model with D -dimer testing in these patients was 99.5% (CI, 99.1% to 100%). CONCLUSION: Managing patients for suspected pulmonary embolism on the basis of pretest probability and D -dimer result is safe and decreases the need for diagnostic imaging.     

Diagnostic Value of 18F-Fluorodeoxyglucose Positron Emission Tomography Computed Tomography in Prosthetic Pulmonary Valve Infective Endocarditis

ObjectivesThe aim of this study was to assess the diagnostic performances of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) in congenital heart disease (CHD) patients with pulmonary prosthetic valve or conduit endocarditis (PPVE) suspicion.BackgroundPPVE is a major issue in the growing CHD population. Diagnosis is challenging, and usual imaging tools are not always efficient or validated in this specific population. Particularly, the diagnostic yield of ¹⁸F-FDG PET/CT remains poorly studied in PPVE.MethodsA retrospective multicenter study was conducted in 8 French tertiary centers. Children and adult CHD patients who underwent ¹⁸F-FDG PET/CT in the setting of PPVE suspicion between January 2010 and May 2020 were included. The cases were initially classified as definite, possible, or rejected PPVE regarding the modified Duke criteria and finally by the Endocarditis Team consensus. The result of ¹⁸F-FDG PET/CT had been compared with final diagnosis consensus used as gold-standard in our study.ResultsA total of 66 cases of PPVE suspicion involving 59 patients (median age 23 years, 73% men) were included. Sensitivity, specificity, positive predictive value, and negative predictive value of ¹⁸F-FDG PET/CT in PPVE suspicion were respectively: 79.1% (95% CI: 68.4%-91.4%), 72.7% (95% CI: 60.4%-85.0%), 91.9% (95% CI: 79.6%-100.0%), and 47.1% (95% CI: 34.8%-59.4%). ¹⁸F-FDG PET/CT findings would help to correctly reclassify 57% (4 of 7) of possible PPVE to definite PPVE.ConclusionsUsing ¹⁸F-FDG PET/CT improves the diagnostic accuracy of the Duke criteria in CHD patients with suspected PPVE. Its high positive predictive value could be helpful in routine to shorten diagnosis and treatment delays and improve clinical outcomes.