CT angiography for pulmonary embolism in the emergency department: investigation of a protocol by 20 ml of high-concentration contrast medium (original) (raw)
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PubMed, 2013
Background: Pulmonary embolism (PE) is a relatively common and potentially life threatening clinical condition with estimated prevalence to be 0.4%. Early diagnosis of PE followed by adequate treatment reduces the risk of major complications. Multislice computed tomography pulmonary angiography (CTPA) currently constitutes an imaging modality of choice in patients with suspicion of PE. Computed tomography venography (CTV) of lower limb veins and CTPA can be performed simultaneously, allowing for visualization of lower limb deep vein thrombosis (DVT). Additionally, dual energy CT scanners enable the evaluation of lung perfusion which is of high value in indirect detection of pulmonary arterial microembolisms. Objectives: The goal of the study was to assess the diagnostic value of a 64-detector CT scanner in the detection of both acute and chronic PE in patients with clinical suspicion of PE based on clinical scores. Material and methods: Retrospective analysis of CTPA performed between 2010 and 2012 in 102 consecutive patients (64 women, 38 men) with clinical suspicion of PE based on clinical scores (first of all the Wells score) and elevated D-dimer level was carried out. The patients' median age was 68.9 (range between 34 and 91). The examinations were carried out with a 64-detector CT scanner, using a "pulmonary embolism" protocol. The volume of contrast agent ranged from 60 to 70 mL, depending on the patient's body mass. The contrast medium was administered with an injection rate 4.0-5.0 mL/s. The concentration of the contrast medium in the main pulmonary artery (MPA) was monitored in every case with the use of a 'smart-prep' method. Scanning was started a few seconds (4-6) after reaching a plateau by the contrast medium in MPA. Additionally, in selected patients CTV was performed and/or lung perfusion was evaluated. Results: Evidence of PE was demonstrated in 32 of 102 (31.4%) analyzed patients (pts). In 19 patients, centrally localized clots were visualized. Additionally, in 32 patients, lobar, segmental and proximal subsegmental filling defects corresponding to thrombo-embolic material were demonstrated. Moreover, in 14 patients, distal subsegmental filling defects were shown. Alternative diagnoses included: heart failure-related congestion (21 pts), pneumonia (19 pts) and malignancy (5 pts). Conclusions: The multislice CTPA is an extremely useful imaging modality in patients with clinical suspicion of PE. The examination enables not only the analysis of pulmonary vessels but also evaluation of pulmonary parenchyma and mediastinum. The collimation of 0.625 mm makes it possible to detect the small foci of peripheral embolism.
European Radiology
Objective To investigate the feasibility and image quality of high-pitch CT pulmonary angiography (CTPA) with reduced iodine volume in normal weight patients. Methods In total, 81 normal weight patients undergoing CTPA for suspected pulmonary arterial embolism were retrospectively included: 41 in high-pitch mode with 20 mL of contrast medium (CM); and 40 with normal pitch and 50 mL of CM. Subjective image quality was assessed and rated on a 3-point scale. For objective image quality, attenuation and noise values were measured in all pulmonary arteries from the trunk to segmental level. Contrast-to-noise ratio (CNR) was calculated. Radiation dose estimations were recorded. Results There were no statistically significant differences in patient and scan demographics between high-pitch and standard CTPA. Subjective image quality was rated good to excellent in over 90% of all exams with no significant group differences (p = 0.32). Median contrast opacification was lower in high-pitch CTP...
Journal of community hospital internal medicine perspectives, 2013
To determine if computed tomographic pulmonary angiography (CTPA) was overemployed in the evaluation of hospitalized patients with suspected acute pulmonary embolism (PE). Data were gathered retrospectively on hospitalized patients (n=185) who had CTPA for suspected PE between June and August 2009 at our institution. CTPA was done in 185 hospitalized patients to diagnose acute PE based on clinical suspicion. Of these, 30 (16.2%) patients were tested positive for acute PE on CTPA. The Well's pretest probability for PE was low, moderate, and high in 77 (41.6%), 83 (44.9%), and 25 (13.5%) patients, respectively. Out of the 30 PE-positive patients, pretest probability was low in 2 (6.6%), moderate in 20 (66.7%), and high in 8 (26.6%) (p=0.003). Modified…
Insights into Imaging, 2014
Objectives To determine the diagnostic yield of computed tomography scanning of the pulmonary arteries (CTPA) in our centre and factors associated with it. Differences between specialties as well as adherence to protocol were investigated. Methods All patients receiving a first CTPA for pulmonary embolism (PE) in 2010 were included. Data about relevant clinical information and the requesting specialty were retrospectively obtained. Differences in diagnostic yield were tested using a chi-squared test. Independent predictors were identified with multivariate logistic regression. Results PE on CTPA was found in 224 of the 974 patients (23 %). Between specialties, diagnostic yield varied from 19.5 to 23.9 % (p=0.20). Independent predictors of diagnostic yield were: age, sex, D-dimer, cough, dyspnea, cardiac history, chronic obstructive pulmonary disease (COPD), atelectasis/consolidation, intrapulmonary mass and/or interstitial pulmonary disease on CT. Wells scores were poorly documented (n=127, 13.0 %). Poor adherence to protocol was also shown by a high amount of unnecessary D-dimer values with a high Wells-score (35 of 58; 58.6 %). Conclusions The diagnostic yield of CTPA in this study was relatively high in comparison with other studies (6.7-31 %). Better adherence to protocol might improve the diagnostic yield further. A prospective study could confirm the independent predictors found in this study. Teaching Points • Pulmonary embolism is potentially life-threatening and requires quick and reliable diagnosis. • Computed tomography of the pulmonary arteries (CTPA) provides this reliable diagnosis. • Several independent predictors of diagnostic yield of CTPA for pulmonary embolism were identified. • Diagnostic yield of CTPA did not differ between requesting specialties in our Hospital. • Better protocol adherence could improve the diagnostic yield of CTPA for pulmonary embolism.
Academic Radiology, 2006
Rationale and Objectives. Our aim is to document current imaging practices for diagnosing acute pulmonary embolism (PE) among physicians practicing in the United States and explore factors associated with these practices. Materials and Methods. Between September 2004 and February 2005, we surveyed by mail 855 physicians selected at random from membership lists of three professional organizations. Physicians reported their imaging practices and experiences in managing patients with suspected acute PE during the preceding 12 months. Results. Completed questionnaires were received from 240 of 806 eligible participants (29.8%) practicing in 44 states: 86.7% of respondents believed that computed tomographic pulmonary angiography (CTPA) was the most useful imaging procedure for patients with acute PE compared with 8.3% for ventilation-perfusion (V-P) scintigraphy and 2.5% for conventional pulminary angiography (PA). After chest radiography, CTPA was the first imaging test requested 71.4% of the time compared with V-P scintigraphy (19.7%) and lower-limb venous ultrasound (5.8%). Participants received indeterminate or inconclusive results 46.4% of the time for V-P scintigraphy, 10.6% of the time for CTPA, and 2.2% of the time for PA. CTPA was available around the clock to 88.3% of participants compared with 53.8% for V-P scintigraphy and 42.5% for PA. A total of 68.6% of respondents received CTPA results in 2 hours or less (vs 37.5% for V-P scintigraphy and 22.9% for PA). CTPA also provided an alternative diagnosis to PE or showed other significant abnormalities 28.5% of the time, and these findings frequently altered management. Conclusion. US clinicians unequivocally prefer CTPA in patients with suspected acute PE. Reasons for this preference include availability and timely reporting, a lower rate of inconclusive results, and the additional diagnostic capabilities that CTPA can provide.
This study was undertaken to evaluate the use of computed tomography pulmonary angiography (CTPA) in patients with pulmonary embolism (PE) who were followed in the emergency department (ED). The files and computer records of 850 patients older than 16 years of age who were seen in the Hacettepe University Hospital ED between April 10, 2001, and December 1, 2005, and who required CTPA for PE prediagnosis and/or another diagnosis, were studied retrospectively. PE was identified by CTPA in 9.4% of 416 women and in 5.8% of 434 men. A significant difference (P<.05) was noted in the women and men in whom PE was detected. The mean age of the patients was 58.13±17.88 y (range, 16–100 y). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for clinical susceptibility to PE among patients who underwent CTPA were assessed at 95.3%, 48.2%, 13%, and 99.2%, respectively. CTPA was done for different reasons: aortic aneurysm dissection (n=1), cough distinctive diagnosis (n=1), dyspnea distinctive diagnosis (n=6), chest pain distinctive diagnosis (n=3), PE prediagnosis (n=51), and other reasons (n=2). Also, sensitivity, specificity, PPV, and NPV were found to be 95.4%, 16.2%, 14.4%, and 96%, respectively, for D-dimer. CTPA, which is accessible on a 24-h basis in the ED, is a valuable tool for the diagnosis of PE.
Ultrasound Assessment of Pulmonary Embolism in Patients Receiving CT Pulmonary Angiography
CHEST Journal, 2014
Original Research angiography (CTPA) has high sensitivity and specificity for PE and is the reference standard for the diagnosis. 1 In addition to its use in making the diagnosis of PE, CTPA may provide the clinician with an alternative diagnosis to PE. The use of CTPA results in signifi cant exposure to ionizing radiation, as well as a risk of contrast nephropathy, so the clinician has a responsibility to avoid its use whenever possible. Lower T he diagnosis of pulmonary embolism (PE) requires recognition of its variable presentation and the appropriate use of radiologic imaging in combination with estimation of pretest probability. CT pulmonary Background: CT pulmonary angiography (CTPA) is considered the gold standard for the diagnosis of pulmonary embolism (PE) and is frequently performed in patients with cardiopulmonary complaints. However, indiscriminate use of CTPA results in signifi cant exposure to ionizing radiation and contrast. We studied the accuracy of a bedside ultrasound protocol to predict the need for CTPA. Methods: This was an observational study performed by pulmonary/critical care physicians trained in critical care ultrasonography. Screening ultrasonography was performed when a CTPA was ordered to rule out PE. The ultrasound examination consisted of a limited ECG, thoracic ultrasonography, and lower extremity deep venous compression study. We predicted that CTPA would not be needed if either DVT was found or clear evidence of an alternative diagnosis was established. CTPA parenchymal and pleural fi ndings, and, when available, formal DVT and ECG results, were compared with our screening ultrasound fi ndings. Results: Of 96 subjects who underwent CTPA, 12 subjects (12.5%) were positive for PE. All 96 subjects had an ultrasound study; two subjects (2.1%) were positive for lower extremity DVT, and 54 subjects (56.2%) had an alternative diagnosis suggested by ultrasonography, such as alveolar consolidation consistent with pneumonia or pulmonary edema, which correlated with CTPA fi ndings. In no patient did the CTPA add an additional diagnosis over the screening ultrasound study. Conclusions: We conclude that ultrasound examination indicated that CTPA was not needed in 56 of 96 patients (58.3%). A screening, point-of-care ultrasonography protocol may predict the need for CTPA. Furthermore, an alternative diagnosis can be established that correlates with CTPA. This study needs further verifi cation, but it offers a possible approach to reduce the cost and radiation exposure that is associated with CTPA.
Iranian Journal of Radiology, 2015
The use of computed tomography pulmonary angiography (CTPA) has been increased during the last decade. Objectives: We studied the adherence to current diagnostic recommendations for evaluation of pulmonary embolism in a teaching hospital of Tehran University of Medical Sciences. Patients and Methods: The registered medical records (Wells scores and serum D-dimer level) of all patients whose CTPA was performed with suspicion of pulmonary thromboembolism (PTE) were studied retrospectively. Modified Wells score of each patient was determined without being aware of the CTPA results. The patients were categorized to those with a high (likely) clinical probability (score > 4) and low (unlikely) clinical probability (score≤ 4) of PTE. Results: During a 6-month period, 82 patients who underwent CTPA were included. The prevalence of PTE was 62.2% in the group of subjects with a likely clinical risk. In 45 (54.8%) of those patients whose CTPA was requested, the PTE was unlikely based on modified Wells criteria. In the clinically unlikely group, serum D-dimer assay was done in 15 out of 45 (33.3%), while it was inappropriately checked in 10 out of 37 (27.0%) with a clinically likely risk. General adherence rate to diagnostic algorithm of PTE was 43.9%. Conclusions: There is still excessive unjustified concern of PTE in less trained physicians leading to excessive diagnostic work-up. Loyalty to the existing guideline for management of suspected PTE in educational hospitals and supervision of attending physicians could prevent overuse of CTPA.
Image Quality and Radiation Dose of Pulmonary CT Angiography Performed Using 100 and 120 kVp
American Journal of Roentgenology, 2012
P ulmonary CT angiography (CTA) performed with MDCT facilitates rapid and accurate diagnosis of pulmonary embolism (PE) [1]. The technique is widely accessible, is quick to perform, and has a high sensitivity (94-100%) and specificity (89-100%) for the diagnosis of acute PE [1, 2]. In addition, pulmonary CTA may show additional thoracic abnormalities in patients referred for exclusion of PE [1, 3]. Therefore, pulmonary CTA is widely accepted as the primary imaging modality for the investigation of patients with suspected PE. However, because PE is diagnosed in fewer than 10% of all pulmonary CTA examinations [1, 4, 5], there is increasing concern regarding the riskbenefit ratio for this examination particularly in younger patients and in women who are at higher risk of carcinogenesis from diagnostic