The Effect of Limiting the Scan Range of Computed Tomography Pulmonary Angiography (to Reduce Radiation Exposure) on the Detection of Pulmonary Embolism: A Systematic Review

(1) Background: Computed tomography pulmonary angiography (CTPA) is the standard imaging test for the evaluation of acute pulmonary embolism (PE), but it is associated with patients’ exposure to radiation. Studies have suggested that radiation exposure can be reduced without compromising PE detection by limiting the scan range (the z-axis, going from up to down); (2) Methods: A literature search was conducted in MEDLINE and EMBASE on 17 July 2021. Studies were included if they enrolled patients who had undergone a CTPA and described the yield of PE diagnoses, number of missed filling defects and/or other diagnoses using a reduced z-axis in comparison to a full-length scan. To assess risk of bias, we modified an existing risk of bias tools for observational studies, the Newcastle-Ottawa Scale. Results were synthesized in a narrative review. Primary outcomes were the number of missed PE diagnoses (based on at least one filling defect) and filling defects; the secondary outcome was the number of other missed findings; (3) Results: Eleven cohort studies and one case-control study were included reporting on a total of 3955 scans including 1025 scans with a diagnosis of PE. Six different reduced scan ranges were assessed; the most studied was from the top of the aortic arch to below the heart, in which no PEs were missed (seven studies). One sub-segmental PE was missed when the scan coverage was 10 cm starting from the bottom of the aortic arch and 14.7 cm starting from the top of the arch. Five studies that reported on other findings all found that other diagnoses were missed with a reduced z-axis. Most of the included studies had a high risk of bias; (4) Conclusions: CTPA scan coverage reduction from the top of aortic arch to below the heart reduced radiation exposure without affecting PE diagnoses, but studies were generally at high risk of bias.

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Prediction of chronic thromboembolic pulmonary hypertension with standardised evaluation of initial computed tomography pulmonary angiography performed for suspected acute pulmonary embolism

European Radiology ◽

10.1007/s00330-021-08364-0 ◽

2021 ◽

Author(s):

Gudula J. A. M. Boon ◽

Yvonne M. Ende-Verhaar ◽

Ludo F. M. Beenen ◽

Johan Coolen ◽

Marion Delcroix ◽

...

Keyword(s):

Computed Tomography ◽

Pulmonary Embolism ◽

Pulmonary Hypertension ◽

High Risk ◽

Acute Pulmonary Embolism ◽

Chronic Thromboembolic Pulmonary Hypertension ◽

Expert Judgment ◽

Pulmonary Angiography ◽

Computed Tomography Pulmonary Angiography ◽

Thromboembolic Pulmonary Hypertension

Abstract Objectives Closer reading of computed tomography pulmonary angiography (CTPA) scans of patients presenting with acute pulmonary embolism (PE) may identify those at high risk of developing chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to validate the predictive value of six radiological predictors that were previously proposed. Methods Three hundred forty-one patients with acute PE were prospectively followed for development of CTEPH in six European hospitals. Index CTPAs were analysed post hoc by expert chest radiologists blinded to the final diagnosis. The accuracy of the predictors using a predefined threshold for ‘high risk’ (≥ 3 predictors) and the expert overall judgment on the presence of CTEPH were assessed. Results CTEPH was confirmed in nine patients (2.6%) during 2-year follow-up. Any sign of chronic thrombi was already present in 74/341 patients (22%) on the index CTPA, which was associated with CTEPH (OR 7.8, 95%CI 1.9–32); 37 patients (11%) had ≥ 3 of 6 radiological predictors, of whom 4 (11%) were diagnosed with CTEPH (sensitivity 44%, 95%CI 14–79; specificity 90%, 95%CI 86–93). Expert judgment raised suspicion of CTEPH in 27 patients, which was confirmed in 8 (30%; sensitivity 89%, 95%CI 52–100; specificity 94%, 95%CI 91–97). Conclusions The presence of ≥ 3 of 6 predefined radiological predictors was highly specific for a future CTEPH diagnosis, comparable to overall expert judgment, while the latter was associated with higher sensitivity. Dedicated CTPA reading for signs of CTEPH may therefore help in early detection of CTEPH after PE, although in our cohort this strategy would not have detected all cases. Key Points • Three expert chest radiologists re-assessed CTPA scans performed at the moment of acute pulmonary embolism diagnosis and observed a high prevalence of chronic thrombi and signs of pulmonary hypertension. • On these index scans, the presence of ≥ 3 of 6 predefined radiological predictors was highly specific for a future diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH), comparable to overall expert judgment. • Dedicated CTPA reading for signs of CTEPH may help in early detection of CTEPH after acute pulmonary embolism.

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Serial use of existing clinical decisions aids can reduce computed tomography pulmonary angiography for pulmonary embolism

Internal and Emergency Medicine ◽

10.1007/s11739-021-02703-1 ◽

2021 ◽

Author(s):

Robert Russell Ehrman ◽

Adrienne Nicole Malik ◽

Reid Kenneth Smith ◽

Zeid Kalarikkal ◽

Andrew Huang ◽

...

Keyword(s):

Computed Tomography ◽

Pulmonary Embolism ◽

Pulmonary Angiography ◽

Clinical Decisions ◽

Computed Tomography Pulmonary Angiography

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Early Pulmonary Embolism Detection from Computed Tomography Pulmonary Angiography Using Convolutional Neural Networks

2020 Joint 9th International Conference on Informatics, Electronics & Vision (ICIEV) and 2020 4th International Conference on Imaging, Vision & Pattern Recognition (icIVPR) ◽

10.1109/icievicivpr48672.2020.9306659 ◽

2020 ◽

Author(s):

Ching-Yuan Yu ◽

Yun-Chien Cheng ◽

Chin Kuo

Keyword(s):

Computed Tomography ◽

Neural Networks ◽

Pulmonary Embolism ◽

Convolutional Neural Networks ◽

Pulmonary Angiography ◽

Computed Tomography Pulmonary Angiography

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On multislice computed tomography pulmonary angiography and ventilation/perfusion scanning for the diagnostic work-up of suspected pulmonary embolism

European Journal of Internal Medicine ◽

10.1016/j.ejim.2010.09.009 ◽

2011 ◽

Vol 22 (1) ◽

pp. 122-123

Author(s):

Javier Galipienzo ◽

Julio Flores ◽

Jaime García de Tena

Keyword(s):

Computed Tomography ◽

Pulmonary Embolism ◽

Multislice Computed Tomography ◽

Pulmonary Angiography ◽

Suspected Pulmonary Embolism ◽

Computed Tomography Pulmonary Angiography ◽

Diagnostic Work ◽

Work Up ◽

Diagnostic Work Up

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CORRELATION OF D-DIMER LEVEL WITH THE PRESENCE AND SEVERITY OF PULMONARY EMBOLISM ON COMPUTED TOMOGRAPHY PULMONARY ANGIOGRAPHY

10.36106/ijsr/1421349 ◽

2020 ◽

pp. 33-34

Author(s):

Mantavya Patel ◽

Sanjay Paliwal ◽

Rachit Saxena

Keyword(s):

Computed Tomography ◽

Pulmonary Embolism ◽

Early Diagnosis ◽

Pulmonary Angiography ◽

Clinical Suspicion ◽

Early Prediction ◽

Computed Tomography Pulmonary Angiography ◽

Negative Prediction ◽

D Dimer

Introduction: Early diagnosis of pulmonary embolism can reduce morbidity and motility. D-dimer is well known parameter having high negative prediction value. This study focused on role of D-dimer in early prediction of presence and severity of pulmonary embolism. Material and Methods: Thirty patients with clinical suspicion of pulmonary embolism along with high D-dimer value were included in this study. All selected patients underwent computed tomography pulmonary angiography assessment. D-dimer value was correlated with presence and proximity of pulmonary embolism. Results: Out of thirty selected patients 50% had pulmonary embolism on computed tomography pulmonary angiography assessment. D-dimer value correlated well with presence and proximity of pulmonary embolism. Conclusion: D-dimer value more than 4000 ng/ml had high positive prediction value (79%) in suspected clinical cases. Value more than 8000 ng/ml further improve value to nearly 100% in suspected cases.

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