The role of computed tomography in the diagnosis of acute and chronic pulmonary embolism

Abstract

A cute pulmonary embolism (PE) is the third most common cardiovascular condition, after coronary artery disease and stroke (1). Due to lack of specific sets of symptoms that accurately predict or exclude the diagnosis of acute PE, the diagnosis strongly relies on noninvasive imaging techniques. Diagnostic strategies for evaluating PE have undergone important changes over the past decades (2). Due to rapid technical advances in speed and spatial resolution, the utility of computed tomography (CT) angiography has been recognized in vascular imaging. Particularly, after the development of multidetector row CT in 1998 (3), CT pulmonary angiography (CTPA) has become the imaging method of choice in the diagnosis of acute PE (4). CTPA has advantages over conventional invasive X-ray pulmonary angiography and nuclear ventilation-perfusion (V/Q) imaging. CT is a widely available, fast and noninvasive technique, has the capability to directly visualize emboli, and may provide alternative diagnoses (4).Despite adequate diagnosis and anticoagulant therapy, death rate after a diagnosis of acute PE is still 8%-15% (5, 6). The prognosis of acute PE mainly depends on residual pulmonary circulation and the severity of right ventricular (RV) dysfunction (7). Recent studies have shown that CT permits the assessment of acute right-sided heart failure. Furthermore, CT can predict adverse clinical outcome by using the RV/left ventricular (LV) diameter ratio (8, 9) or RV ejection fraction in patients with PE (10).The aim of this review is to discuss the developments of CT in PE diagnosis, and to analyze the added value of CT in estimating PE severity and prognosis. Furthermore, CT findings of chronic thromboembolic pulmonary arterial hypertension (CTEPH) as a complication of acute PE will be discussed. CT developments in PE diagnosisHistorically, pulmonary angiography and nuclear planar V/Q-imaging were the main imaging methods used for diagnosing PE. Both methods have recognized limitations. Pulmonary angiography has previously been regarded as reference standard, but the method CHEST IMAGING REVIEW ABSTRACT Pulmonary embolism (PE) is a potentially life threatening condition requiring adequate diagnosis and treatment. Computed tomography pulmonary angiography (CTPA) is excellent for including and excluding PE, therefore CT is the first-choice diagnostic imaging technique in patients suspected of having acute PE. Due to its wide availability and low invasiveness, CTPA tends to be overused. Correct implementation of clinical decision rules in diagnostic workup for PE improves adequate use of CT. Also, CT adds prognostic value by evaluating right ventricular (RV) function. CT-assessed RV dysfunction and to lesser extent central emboli location predicts PE-related mortality in normotensive and hypotensive patients, while PE embolic obstruction index has limited prognostic value. Simple RV/left ventricular (LV) diameter ratio measures >1.0 already predict risk for adverse outcome, whereas ratios <1.0 can safely exclude adverse outcome. Con...

The Diagnostic Accuracy and Impact of Computer-Aided Diagnosis of Pulmonary Emboli Using CT Pulmonary Angiography

“…These findings within Table 1 correlate to the review by Doğan et al [15] where the variation in sensitivity and specificity for radiologist diagnosis of PE was reviewed and respectively re- MDCT: multi-detector CT ported as ranging from 83-100%, and from 89-96%, again with the exception of 68-100% sensitivity reported by Wittenberg et al [13]. The study by Wittenberg et al [13] also further reported on individual reporting radiologist's sensitivity and specificity for diagnosis of patients with PE, and can account for the greater range in sensitivity (68-100%) reported in their study, where one particular radiologist had a lower diagnostic sensitivity of 68%.…”

“…Worldwide acceptance of CTPA as a gold standard diagnostic tool for PE has been achieved following the PIOPED II study and reviews like that published by Doğan et al [15]. Although a high sensitivity for PE diagnosis has been established, there is still a false negative proportion of 13% as per the PIOPED II results, and this could lead to significant negative health outcomes.…”

The Results of Thrombolytic Treatment in Patients With High-risk Pulmonary Embolism

“…Dogan et al analyzed the role of CT in the diagnosis of acute and chronic PE. 9 International multicenter echocardiographic are comparable for predicting 30-day mortality. [14][15][16][17][18] These results were consistent with our study.…”

Computer-Aided Detection, Pulmonary Embolism, Computerized Tomography Pulmonary Angiography: Current Status

“…Over the last decade, the clinical role of CTPA examination has undergone extensive scientific investigations [7][8][9][10]. The largest and most significant collaborative clinical trial was conducted in 2006 [10].…”

“…On the other hand, based on the PE location is lobar, segmental, or subsegmental vessels, the PPV was 97, 68, and 25%, respectively. The defects at extreme sites of pulmonary vascular branches (segmental and subsegmental vessels) exhibit less observability, and consequently more challenging to radiologists, than lobar and main PA clots.A recent report, in 2015, was published by Dogan et al in the Netherlands; this study reviewed different CTPA clinical trials and reported that the sensitivity and specificity of CTPA scans may vary between the range of 83-100% and 89-96%, respectively[8]. The NPV was 96-99% showing the high CTPA scan's certainty in ruling out PE; a negative CTPA can safely exclude PE.…”