Multiplanar and 3D Imaging Modalities for the Evaluation of Right Ventricle to Left Ventricle Ratios in Patients with Pulmonary Embolism

In patients with acute pulmonary embolism (PE), early risk stratification is essential to determine effective therapeutic management. Right ventricle to left ventricle (RV/LV) ratio measurement is a strong predictor of clinical outcomes, such as mortality. Computerized tomographic pulmonary angiography (CTPA) is an accessible method often used for rapid measurement of RV/LV ratios.

RV/LV ratios performed in the standard axial view may not represent the true maximum diameter. Therefore, this study compares a reformatted four-chamber RV/LV ratio and a 3D volume RV/LV ratio versus standard axial RV/LV ratio as predictors of pulmonary embolism severity classification.


Materials and Methods:

This retrospective review includes patients with PE who received interventional thrombolytic therapy or mechanical thrombectomy from July 2022 to March 2023. An internal procedural database was queried and patients with imaging-confirmed acute PE were included (n=40). Patients without pre-intervention CT or axial thin slices available for analysis were excluded. Diameter-based RV/LV ratios were measured in the standard axial view and with multiplanar imaging modalities in Visage to obtain a formatted multiplanar four-chamber view (FMPV). RV/LV Volume ratios were calculated using the 3D region of interest (ROI) modality in Visage. RV/LV ratios were correlated to European Society of Cardiology classifications of pulmonary embolism severity. 



Results:

Our data shows axial and reformatted four-chamber ratios were well correlated (correlation coefficient, 0.777), and axial and 3D volume ratios were well correlated (correlation coefficient, 0.817). Logistic regression showed that RV/LV ratios measured with the reformatted four-chamber view were significantly associated with pulmonary embolism severity classifications and that larger RV/LV ratios measured in this view predicted greater pulmonary embolism severity classification (coefficient, -1.286; p=0.0183). RV/LV ratios measured with the standard axial view (coefficient, -0.737; p=0.162) and 3D volume modalities (coefficient, -

0.137; p=0.304) were not statistically associated with pulmonary embolism severity classifications. 



Conclusion:

Our data suggests a reformatted four-chamber measurement of RV/LV ratio better predicts pulmonary embolism severity classification than standard axial or 3D volume measurements. CTPA can be used as a dual diagnostic and prognostic tool when calculating RV/LV ratios using a reformatted four-chamber view.