Assessment of correlation between CT angiographic clot load score, pulmonary perfusion defect score and global right ventricular function with dual-source CT for acute pulmonary embolism

Does Adding the Pulmonary Infarction and Right Ventricle to Left Ventricle Diameter Ratio to the Qanadli Index (A Combined Qanadli Index) More Accurately, Predict Short-Term Mortality in Patients with Pulmonary Embolism?

Background  The Qanadli index can be used to assess the severity of pulmonary arterial involvement in patients with acute pulmonary embolism. However, it seems that considering pulmonary infarction and right ventricle/left ventricle (RV/LV) ratio along with this index (called the combined Qanadli index) can provide a more accurate view of changes in cardiovascular parameters in these patients and help predict mortality in a better manner. In this regard, we evaluated the ability of the combined Qanadli index versus the Qanadli index in predicting short-term mortality in patients with pulmonary embolism. Methods  This retrospective study enrolled 234 patients with acute pulmonary embolism. Patients were divided into two groups: those who expired in 30 days and who survived. Then they were evaluated by computed tomography angiography of pulmonary arteries. The RV/LV diameter ratio and also pulmonary artery obstruction index (PAOI) were calculated. The patient's computed tomography scans were reviewed for pulmonary infarction. By adding the RV/LV ratio and pulmonary infarction to PAOI, a new index called the modified Qanadli score was made. Univariable and multivariable logistic regression was done for finding predictors of mortality. Results  Nine cases (40%) of patients in the mortality group and 42 (20%) of survivors had ischemic heart disease and the difference was significantly meaningful. The mean Qanadli index in the mortality group was 16.8 ± 8.45 and in survivors was 8.3 ± 4.2. By adding the pulmonary infarction score and PAOI score to RV/LV ratio score, the odds ratio (OR) for predicting mortality increased significantly to 13 and 16, respectively, which were significantly meaningful. Based on our findings, the highest OR for predicting short-term mortality was obtained through a combined Qanadli index (PAOI score + pulmonary infarction score + RV/LV score) that was 17 in univariable and 18 in multivariable logistic regression analysis ( p -value = 0.015). Conclusion  The new combined Qanadli index has more ability than the Qanadli index and RV/LV ratio for predicting changes in cardiovascular parameters and short-term mortality in patients with pulmonary embolism.

Dual-energy CT in pulmonary vascular disease

Dual-energy CT (DECT) imaging is a technique that extends the capabilities of CT beyond that of established densitometric evaluations. CT pulmonary angiography (CTPA) performed with dual-energy technique benefits from both the availability of low kVp CT data and also the concurrent ability to quantify iodine enhancement in the lung parenchyma. Parenchymal enhancement, presented as pulmonary perfused blood volume maps, may be considered as a surrogate of pulmonary perfusion. These distinct capabilities have led to new opportunities in the evaluation of pulmonary vascular diseases. Dual-energy CTPA offers the potential for improvements in pulmonary emboli detection, diagnostic confidence, and most notably severity stratification. Furthermore, the appreciated insights of pulmonary vascular physiology conferred by DECT have resulted in increased use for the assessment of pulmonary hypertension, with particular utility in the subset of patients with chronic thromboembolic pulmonary hypertension. With the increasing availability of dual energy-capable CT systems, dual energy CTPA is becoming a standard-of-care protocol for CTPA acquisition in acute PE. Furthermore, qualitative and quantitative pulmonary vascular DECT data heralds promise for the technique as a "one-stop shop" for diagnosis and surveillance assessment in patients with pulmonary hypertension. This review explores the current application, clinical value, and limitations of DECT imaging in acute and chronic pulmonary vascular conditions. It should be noted that certain manufacturers and investigators prefer alternative terms, such as spectral or multi-energy CT imaging. In this review, the term dual energy is utilised, although readers can consider these terms synonymous for purposes of the principles explained.

Clinical importance of the distribution of pulmonary artery embolism in acute pulmonary embolism

Objective

To explore the clinical importance of the distribution of pulmonary artery embolism in acute pulmonary embolism (APE).

Methods

Sixty-four patients with APE were classified into mixed-type and distal-type pulmonary embolism groups. Their right ventricular systolic pressure (RVSP) and disease duration were recorded, and the diameter of their right ventricles was measured by ultrasound. The computed tomography angiographic clot load was determined as a Mastora score.

Results

Patients with distal-type pulmonary embolisms had significantly lower RVSPs (44.92 ± 17.04 vs 55.69 ± 17.66 mmHg), and significantly smaller right ventricular diameters (21.08 ± 3.06 vs 23.37 ± 3.48 mm) than those with mixed-type pulmonary embolisms. Additionally, disease duration was significantly longer in patients with distal-type pulmonary embolisms (14.33 ± 11.57 vs 8.10 ± 7.10 days), and they had significantly lower Mastora scores (20.91% ± 18.92% vs 43.96% ± 18.30%) than patients with mixed-type pulmonary embolisms. After treatment, RVSPs decreased significantly in patients with both distal-type and mixed-type pulmonary embolisms. Right ventricle diameters also decreased significantly in patients with mixed-type pulmonary embolisms after treatment.

Conclusion

Patients with mixed-type pulmonary embolisms are significantly more susceptible to pulmonary hypertension, enlarged right ventricular diameters, and shorter durations of disease than those with distal-type pulmonary embolisms. The distribution of pulmonary artery embolism in APE can provide a clinical reference.

Acute Pulmonary Embolism Severity Assessment Evaluated with Dual Energy CT Perfusion Compared to Conventional CT Angiographic Measurements

The purpose of the study was to investigate whether Dual Energy CT (DECT) can be used as a diagnostic tool to assess the severity of acute pulmonary embolism (PE) by correlating parenchymal perfusion defect volume, obstruction score and right ventricular-to-left ventricular (RV/LV) diameter ratio using CT angiography (CTA) and DECT perfusion imaging. A total of 43 patients who underwent CTA and DECT perfusion imaging with clinical suspicion of acute PE were retrospectively included in the study. In total, 25 of these patients had acute PE findings on CTA. DECT assessed perfusion defect volume (PDvol) were automatically and semiautomatically quantified. Overall, two CTA methods for risk assessment in patients with acute PE were assessed: the RV/LV diameter ratio and the Modified Miller obstruction score. Automatic PDvol had a weak correlation (r = 0.47, p = 0.02) and semiautomatic PDvol (r = 0.68, p < 0.001) had a moderate correlation to obstruction score in patients with confirmed acute PE, while only semiautomatic PDvol (r = 0.43, p = 0.03) had a weak correlation with the RV/LV diameter ratio. Our data indicate that PDvol assessed by DECT software technique may be a helpful tool to assess the severity of acute PE when compared to obstruction score and RV/LV diameter ratio.

Computed Tomography Pulmonary Perfusion for Prediction of Short-Term Clinical Outcome in Acute Pulmonary Embolism

Background  Computed tomography pulmonary angiography (CTPA) is the imaging modality of choice for the diagnosis of acute pulmonary embolism (PE). With computed tomography pulmonary perfusion (CTPP) additional information on lung perfusion can be assessed, but its value in PE risk stratification is unknown. We aimed to evaluate the correlation between CTPP-assessed perfusion defect score (PDS) and clinical presentation and its predictive value for adverse short-term outcome of acute PE.

Patients and Methods  This was an exploratory, observational study in 100 hemodynamically stable patients with CTPA-confirmed acute PE in whom CTPP was performed as part of routine clinical practice. We calculated the difference between the mean PDS in patients with versus without chest pain, dyspnea, and hemoptysis and 7-day adverse outcome. Multivariable logistic regression analysis and likelihood-ratio test were used to assess the added predictive value of PDS to CTPA parameters of right ventricle dysfunction and total thrombus load, for intensive care unit admission, reperfusion therapy and PE-related death.

Results  We found no correlation between PDS and clinical symptoms. PDS was correlated to reperfusion therapy ( n  = 4 with 16% higher PDS, 95% confidence interval [CI]: 3.5–28%) and PE-related mortality ( n  = 2 with 22% higher PDS, 95% CI: 4.9–38). Moreover, PDS had an added predictive value to CTPA assessment for PE-related mortality (from Chi-square 14 to 19, p  = 0.02).

Conclusion  CTPP-assessed PDS was not correlated to clinical presentation of acute PE. However, PDS was correlated to reperfusion therapy and PE-related mortality and had an added predictive value to CTPA-reading for PE-related mortality; this added value needs to be demonstrated in larger studies.

Contrast reflux into the inferior vena cava on computer tomographic pulmonary angiography is a predictor of 24-hour and 30-day mortality in patients with acute pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) is a common disease with a high mortality. Computed tomographic pulmonary angiography (CTPA) represents the current gold standard for the evaluation of patients with suspected PE.

PURPOSE

To search possible CTPA predictors of 24-h and 30-day mortality in PE.

MATERIAL AND METHODS

Overall, 224 patients with PE (46.4% women, mean age 64.7 ± 16.7 years) were acquired. CTPA was performed on a multi-slice CT scanner. The following radiological parameters were estimated: thrombotic obstruction index; diameter of the pulmonary trunk (mm); short axis ratio of right ventricle/left ventricle; diameter of the azygos vein (mm); diameter of the superior and inferior vena cava (mm); and reflux of contrast medium into the inferior vena cava (IVC).

RESULTS

Patients who died within the first 24 h after admission (n = 32, 14.3%) showed a reflux grade 3 into IVC more often than survivors (odds ratio [OR] 7.6, 95% confidence interval [CI] 3.3-17.7; P < 0.001). Other relevant CTPA parameters were diameter of IVC (OR 1.1, 95% CI 1.01-1.21; P = 0.034) and diameter of the pulmonary trunk (OR 0.91, 95% CI 0.82-1.01, P = 0.074), whereas the Mastora score showed nearly no influence (OR 1.01, 95% CI 0.99-1.02, P = 0.406). Furthermore, 61 (27.2%) patients died within the first 30 days after admission. These patients showed a reflux grade 3 into IVC more often than survivors (OR 3.4, 95% CI 1.7-7.0; P = 0.001). Other CTPA parameters, such as diameter of IVC (OR 1.04, 95% CI 0.97-1.12; P = 0.277) and diameter of the pulmonary trunk (OR 0.96, 95% CI 0.89-1.04; P = 0.291), seem to have no relevant influence, whereas Mastora score did (OR 0.99, 95% CI 0.976-0.999, P = 0.045).

CONCLUSION

Subhepatic contrast reflux into IVC is a strong predictor of 24-h and 30-day mortality in patients with acute PE.

Correlation of thrombosed vessel location and clot burden score with severity of disease and risk stratification in patients with acute pulmonary embolism

Objective:

Computed tomography pulmonary angiography (CTPA) is used for the main diagnosis in acute pulmonary embolism (APE). Determining the thrombus location in the pulmonary vascular tree is also important for predicting disease severity. This study aimed to analyze the correlation of the thrombus location and the clot burden with the disease severity and the risk stratification in patients with APE.

Methods:

The study included patients with APE diagnosed by CTPA who were admitted to the hospital between January 28, 2016, and July 1, 2019. Data collected were markers of severity in APE, including patient demographics, comorbidities, length of hospital stay, pulmonary embolism severity index (PESI) score, modified PESI score, Wells score, risk stratification according to the American Heart Association, systolic blood pressure (SBP), right ventricle diameter to left ventricle diameter ratio, pulmonary arterial pressure, brain natriuretic peptide, troponin, D-dimer, and plasma lactate levels, and vessel location of the thrombus, clot burden score, ratio of the pulmonary artery trunk diameter/aortic diameter, superior vena cava diameter (SVC) by CTPA, and survival. All parameters were analyzed in correlation with clot load and vessel location.

Results:

Thrombus vascular location was found to be correlated with risk stratification and negatively correlated with SBP. Simplified Mastora score was correlated with risk stratification, SVC diameter, and D-dimer and negatively correlated with SBP. Occlusion of both the pulmonary artery trunk and any pulmonary artery with thrombus was associated with massive APE.

Conclusion:

The level of the occluded vessel on CTPA may provide the ability to risk-stratify, and the clot burden score may be used for assessing both risk stratification and cardiac strain.

Translation of Quantitative Imaging Biomarkers into Clinical Chest CT

Quantitative imaging has been proposed as the next frontier in radiology as part of an effort to improve patient care through precision medicine. In 2007, the Radiological Society of North America launched the Quantitative Imaging Biomarkers Alliance (QIBA), an initiative aimed at improving the value and practicality of quantitative imaging biomarkers by reducing variability across devices, sites, patients, and time. Chest CT occupies a strategic position in this initiative because it is one of the most frequently used imaging modalities, anatomically encompassing the leading causes of mortality worldwide. To date, QIBA has worked on profiles focused on the accurate, reproducible, and meaningful use of volumetric measurements of lung lesions in chest CT. However, other quantitative methods are on the verge of translation from research grounds into clinical practice, including (a) assessment of parenchymal and airway changes in patients with chronic obstructive pulmonary disease, (b) analysis of perfusion with dual-energy CT biomarkers, and (c) opportunistic screening for coronary atherosclerosis and low bone mass by using chest CT examinations performed for other indications. The rationale for and the key facts related to the application of these quantitative imaging biomarkers in cardiothoracic chest CT are presented. ^©RSNA, 2019 See discussion on this article by Buckler (pp 977-980).

Quantitative CT Evaluation of Small Pulmonary Vessels in Patients with Acute Pulmonary Embolism

RATIONALE AND OBJECTIVES

The objective of this study was to investigate the correlation between the computed tomography (CT) cross-sectional area (CSA) of small pulmonary vessels and the CT obstruction index in patients with acute pulmonary embolism (PE) and the correlation between the changes in these measurements after anticoagulant therapy.

MATERIALS AND METHODS

Fifty-two patients with acute PE were selected for this study. We measured the CSA less than 5 mm² on coronal reconstructed images to obtain the percentage of the CSA (%CSA < 5). CT angiographic index was obtained based on the Qanadli method for the evaluation of the degree of pulmonary arterial obstruction. Spearman rank correlation analysis was used to evaluate the relationship between the initial and the follow-up values and changes in the %CSA < 5 and the CT obstruction index.

RESULTS

There was no significant correlation between the %CSA < 5 and CT obstruction index on both initial (ρ = -0.03, P = 0.84) and follow-up (ρ = -0.03, P = 0.82) assessments. In contrast, there was a significant negative correlation between the changes in %CSA < 5 and the CT obstruction index (ρ = -0.59, P < 0.0001).

CONCLUSIONS

Although the absolute %CSA < 5 and CT obstruction index were not significantly correlated, the changes in the values of the two parameters had a significant correlation. Changes in %CSA < 5, which can be obtained easily, can be used as biomarker of therapeutic response in patients with acute PE.

Central Versus Peripheral Pulmonary Embolism: Analysis of the Impact on the Physiological Parameters and Long-term Survival

BACKGROUND

Studies aimed at assessing whether the emboli lodged in the central pulmonary arteries carry a worse prognosis than more peripheral emboli have yielded controversial results.

AIMS

To explore the impact on survival and long-term prognosis of central pulmonary embolism.

PATIENTS AND METHODS

Consecutive patients diagnosed with acute symptomatic pulmonary embolism by means of computed tomography (CT) angiography were evaluated at episode index and traced through the computed system of clinical recording and following-up. Central pulmonary embolism was diagnosed when thrombi were seen in the trunk or in the main pulmonary arteries and peripheral pulmonary embolism when segmental or subsegmental arteries were affected.

RESULTS

A total of 530 consecutive patients diagnosed with pulmonary embolism were evaluated; 255 patients had central pulmonary embolism and 275 patients had segmental or subsegmental pulmonary embolism. Patients with central pulmonary embolism were older, had higher plasma levels of N-terminal of the prohormone brain natriuretic peptide (NT-ProBNP), troponin I, D-dimer, alveolar-arterial gradient, and shock index (P < .001 for each one). Patients with central pulmonary embolism had an all-cause mortality of 40% while patients with segmental or subsegmental pulmonary embolism (PE) had an overall mortality of 27% and odds ratio of 1.81 [confidence interval (CI) 95% 1.16-1.9]. Survival was lower in patients with central PE than in patients with segmental or subsegmental pulmonary embolism, even after avoiding confounders (P = .018).

CONCLUSIONS

Apart from a greater impact on hemodynamics, gas exchange, and right ventricular dysfunction, central pulmonary embolism associates a shorter survival and an increased long-term mortality.

Non-ECG-gated CT pulmonary angiography and the prediction of right ventricular dysfunction in patients suspected of pulmonary embolism

PURPOSE

Right ventricular dysfunction (RVD) is an important prognostic factor of 30-day mortality in patients with acute pulmonary embolism (PE). The aim of our study was to evaluate whether non-electrocardiogram (ECG)-gated cardiovascular parameters attained during computed tomography pulmonary angiography (CTPA) could predict RVD in patients suspected of PE using ECG-gated cardiac CT angiography as reference.

METHODS

Consecutive patients suspected of PE were referred to a ventilation/perfusion single-photon emission tomography (V/Q-SPECT) as first-line imaging procedure. Patients had a V/Q-SPECT/CT, a CTPA and an ECG-gated cardiac CT angiography performed the same day.

RESULTS

A total of 71 patients were available for analysis. Seventeen patients (24%) had RVD. The non-ECG-gated dimensions of left and right ventricle and the major vessels were correlated with ECG-gated cardiac dimensions. The size of the pulmonary trunk could identify patients with RVD: AUC (0·67, 95% confidence intervals (CIs) 0·52-0·82) as seen in the ROC curve (P<0·05). With a cut-off value of the pulmonary trunk of 29 mm, the sensitivity and specificity were 70·6% and 55·5%, respectively. The positive predictive and negative predictive values for detection of RVD were 59·1% and 85·7%, respectively.

CONCLUSION

In the present study, we demonstrated correlation between ECG-gated cardiac dimensions and non-ECG-gated cardiovascular parameters, however with only moderate diagnostic accuracies. We demonstrated that the dimension of the pulmonary trunk might be of value in detection of patients with RVD. We suggest further studies on the potential value of non-ECG-gated cardiac dimensions in patients suspected of PE.