Higher agreement between readers with deep learning CAD software for reporting pulmonary nodules on CT.

Purpose: The aim was to evaluate the impact of CAD software on the pulmonary nodule management recommendations of radiologists in a cohort of patients with incidentally detected nodules on CT. Methods: For this retrospective study, two radiologists independently assessed 50 chest CT cases for pulmonary nodules to determine the appropriate management recommendation, twice, unaided and aided by CAD with a 6-month washout period. Management recommendations were given in a 4-point grade based on the BTS guidelines. Both reading sessions were recorded to determine the reading times per case. A reduction in reading times per session was tested with a one-tailed paired t-test, and a linear weighted kappa was calculated to assess interobserver agreement. Results: The mean age of the included patients was 65.0 ± 10.9. Twenty patients were male (40 %). For both readers 1 and 2, a significant reduction of reading time was observed of 33.4 % and 42.6 % (p < 0.001, p < 0.001). The linear weighted kappa between readers unaided was 0.61. Readers showed a better agreement with the aid of CAD, namely by a kappa of 0.84. The mean reading time per case was 226.4 ± 113.2 and 320.8 ± 164.2 s unaided and 150.8 ± 74.2 and 184.2 ± 125.3 s aided by CAD software for readers 1 and 2, respectively. Conclusion: A dedicated CAD system for aiding in pulmonary nodule reporting may help improve the uniformity of management recommendations in clinical practice.

Accuracy of single-detector spiral CT in the diagnosis of pulmonary embolism: a prospective multicenter cohort study of consecutive patients with abnormal perfusion scintigraphy.

BACKGROUND: Spiral computed tomography (CT) has emerged as a potentially conclusive diagnostic test to exclude pulmonary embolism (PE) in patients with non-high probability scintigraphy and is already widely used-sometimes as the sole primary diagnostic test in the diagnosis of suspected PE. Its true sensitivity and specificity has, however, not been evaluated previously in a large cohort of consecutive patients. METHODS: In a multicenter prospective study 627 consecutive patients with clinically suspected PE were studied. Patients with normal perfusion scintigraphy were excluded from further analysis. Single-detector spiral CT scanning and ventilation scintigraphy were then performed in all patients to diagnose PE, while pulmonary angiography was performed as the gold standard. The only exceptions were those patients who had both a high-probability VQ scan and a CT scan positive for PE: these patients were considered to have PE and did not undergo additional pulmonary angiography. All imaging tests were read by independent expert panels. RESULTS: Five hundred and seventeen patients were available for complete analysis. The prevalence of PE was 32%. Spiral CT correctly identified 88 of 128 patients with PE, and 92 of 109 patients without PE, for a sensitivity and specificity of 69%[95% confidence interval (CI) 63-75] and 84% (95% CI 80-89), respectively. The sensitivity of spiral CT was 86% (95% CI 80-92) for segmental or larger PE and 21% (95% CI 14-29) in the group of patients with subsegmental PE. CONCLUSION: The overall sensitivity of spiral CT for PE is too low to endorse its use as the sole test to exclude PE. This holds true even if one limits the discussion to patients with larger PE in segmental or larger pulmonary artery branches. We conclude that, in patients with clinically suspected PE and an abnormal perfusion scintigraphy, single-slice detector spiral CT is not sensitive enough to be used as the sole test to exclude PE.

Helical computed tomography and alternative diagnosis in patients with excluded pulmonary embolism.

OBJECTIVE: A clinical diagnosis of pulmonary embolism (PE) is confirmed objectively in 20-30% of patients. Helical computed tomography (CT) can allow an alternative diagnosis to be made. The frequency and validity of alternative diagnoses on helical CT in consecutive patients presenting with clinically suspected PE was assessed. PATIENTS AND METHODS: In all 512 prospectively analyzed patients helical CT scan was performed, and apart from presence or absence of PE, pathologic changes in lung parenchyma, mediastinum, cardiovascular system, pleura and skeleton were recorded. When possible an alternative diagnosis was given and compared with the final diagnosis after 3 months follow-up. RESULTS: In 130 patients (25.4%) PE was excluded and an alternative diagnosis considered likely. In 123 of the 130 patients (94.6%) this diagnosis was unchanged at 3 months follow-up. The diagnoses included pneumonia (n = 67), malignancy (n = 22), pleural fluid (n = 10), cardiac failure (n = 10), COPD (n = 6) and a variety of other causes (n = 15). The diagnosis changed at follow-up in seven patients (5.4%). An initial diagnosis of pneumonia changed to malignancy in two patients and to pleuritis and cardiac failure in one patient each. In two other patients malignancy and chronic obstructive pulmonary disease (COPD) were ruled out and the diagnosis changed to pneumonia. In one patient the final diagnosis remained unknown after an initial suspicion of malignancy. CONCLUSION: In clinically suspected PE helical CT allows a reliable alternative diagnosis to be made in 25.4% of patients. This feature is an unique advantage in comparison with other diagnostic tests and supports the decision of taking helical CT as first line test in suspected PE.

Use of a new monoclonal antibody-based enzyme immunoassay for soluble fibrin to exclude pulmonary embolism. ANTELOPE-Study Group.

We prospectively evaluated the diagnostic performance of a new soluble fibrin assay in 303 consecutive patients with suspected pulmonary embolism and examined potentially useful cut-off levels at which this disease can be safely excluded. In addition, the diagnostic accuracy was calculated in the subgroups of in- and outpatients. The ROC curve of the assay in the total study cohort had an area under the curve of 0.69. The cut-off level associated with a sensitivity and negative predictive value of 100% was 20 ng/ml, but the specificity was only 4%. The cut-off level with a sensitivity of 90% was 30 ng/ml, which corresponded with a specificity and negative predictive value of 27% and 86%. respectively. The diagnostic performance was comparable in the subgroups of in- and outpatients. We conclude that the soluble fibrin assay has a low diagnostic accuracy and seems unsuitable as a screening test for the exclusion of pulmonary embolism.

Clinical evaluation of a monoclonal antibody-based enzyme immunoassay for fibrin degradation products in patients with clinically suspected pulmonary embolism. ANTELOPE-Study Group.

We prospectively evaluated the diagnostic accuracy of the Fibrinostika FbDP assay in 304 consecutive patients with suspected pulmonary embolism and examined potentially useful cut-off points at which the disease can be excluded. The prevalence of pulmonary embolism was 31%. The assay generated an area under the Receiver Operating Characteristic curve of 0.79 (95% CI 0.73-0.84). A cut-off point of 0.05 microg/ml yielded a sensitivity, specificity, negative predictive value and an exclusion efficiency of 100% (95% CI 96-100), 5% (95% CI 2-9), 100% (95% CI 69-100) and 3% (95% CI 2-6), respectively. A clinically useful cut-off point seems to be 0.11 microg/ml which corresponded with a sensitivity, specificity, negative predictive value and an exclusion efficiency of 96% (95% CI 90-99), 27% (95% CI 24-28), 93% (95% CI 84-98) and 20% (95% CI 16-25), respectively. We conclude that the assay has potential clinical utility for the exclusion of pulmonary embolism, but it cannot be used as a sole test.

Observer dependency of the SimpliRed D-dimer assay in 81 consecutive patients with suspected pulmonary embolism.

The SimpliRed D-dimer assay is a whole blood agglutination test for the exclusion of pulmonary embolism (PE) and has been advocated as a reliable rapid bedside alternative to more time-consuming quantitative assays. However, widely differing negative predictive values (77-100%) are reported. This study assessed the intra- and interobserver variability as a possible cause for this wide accuracy range and evaluated the accuracy of the SimpliRed test in 81 consecutive patients with clinically suspected PE. Absolute D-dimer concentration was measured using the Tinaquant (Roche Diagnostics GmbH, Mannheim, Germany) assay. Every assay was immediately scored by one observer and then photographed. Photos were randomised and read twice by two other independent observers. The intraobserver reproducibility was good: kappa=0.81 and 0.73. However, we found poor interobserver reproducibility with kappa=0.47. This seems due to the fact that the SimpliRed test proved difficult to interpret in the 0.3-1.3 microg/mL plasma concentration D-dimer range, which contained 32/81 (40%) patients, 8 of whom had PE. Using pulmonary angiograms and ventilation perfusion lung scans with a concurrent spiral computed tomography scan as a gold standard (25 patients had PE), SimpliRed's accuracy to exclude PE was moderate, with negative predictive values of 0.78 and 0.84. In particular, the two observers scored the SimpliRed test as normal in 12 of 25 and 5 of 25 patients with proven PE. We conclude that SimpliRed is strongly observer-dependent. This explains the varying sensitivities for the detection of venous thromboembolism as reported in previous studies.

Contrast-enhanced spiral computed tomography of the pulmonary arteries: an overview.

Spiral computed tomography is a new noninvasive diagnostic test for pulmonary embolism. The method provides tomographic images of the thorax in the axial plane, which depict the thoracic wall, the mediastinum, the lungs, and the pulmonary vessels. Thrombotic emboli in the vessels are seen as intraluminal filling defects in the contrast-enhanced pulmonary arteries. The physical principles of spiral computed tomography and several technical considerations concerning image quality will be briefly discussed. The accuracy of spiral computed tomography in the detection of pulmonary embolism is discussed by way of an overview of published validation and clinical outcome studies encompassing spiral computed tomography and the diagnosis of pulmonary embolism.

Suspected pulmonary embolism: prevalence and anatomic distribution in 487 consecutive patients. Advances in New Technologies Evaluating the Localisation of Pulmonary Embolism (ANTELOPE) Group.

PURPOSE: To evaluate the prevalence and anatomic distribution of pulmonary embolism (PE) in a group of consecutive patients clinically suspected of having PE. MATERIALS AND METHODS: Four hundred eighty-seven consecutive patients clinically suspected of having PE were examined in six Dutch hospitals from May 1997 through March 1998. Patients underwent ventilation-perfusion (V-P) scintigraphy, spiral computed tomographic (CT) angiography, and/or digital subtraction pulmonary angiography according to a strict diagnostic protocol. Independent readers reviewed all of the diagnostic image studies in centralized readings. The largest pulmonary arterial branch in which PE was detected was recorded. RESULTS: The prevalence of PE was 27% (130 of 487 patients). There was a significant difference in PE size between the high-probability and nondiagnostic V-P scans: The high-probability scans tended to depict larger emboli, but they also showed small subsegmental emboli. Twenty-nine (22%) of 130 patients had subsegmental PE; 23 of these 29 patients had a high-probability V-P scan. CONCLUSION: The largest pulmonary arterial branch with PE was central or lobar in 66 (51%), segmental in 35 (27%), and isolated subsegmental in 29 (22%) patients.