The combination of automated 3-dimensional (3D) volumetry by computed tomography pulmonary angiography with transthoracic echocardiography is superior to either test alone for predicting mean pulmonary arterial pressure (mPAP) and pulmonary hypertension (PH), according to study results published in European Radiology.
In the retrospective study, investigators included a total of 70 patients (mean age, 66.7±12.5 years) who were evaluated for PH by both computed tomography pulmonary angiography and transthoracic echocardiography. Imaging techniques were used to estimate the pulmonary arterial systolic pressure. Findings were compared with the reference, which included gold standard right heart catheterization and quantification of the invasive mPAP. Automated 3D segmentation was used to calculate the volumes of the main pulmonary artery (MPA), right pulmonary artery, and left pulmonary artery. The researchers developed a linear regression model to predict mPAP using these measurements.
Compared with patients without PH, patients with PH had higher mean axial diameters of MPA (24.6±4.1 vs 33.1±5.1, respectively), right pulmonary artery (21.3±4.8 vs 28.5±5.0, respectively), and left pulmonary artery (21.6±5.2 vs 27.1±4.6, respectively; P <.001). The volume of MPA held the strongest association with invasive mPAP compared with right pulmonary artery and left pulmonary artery (P <.001). Use of MPA volume and echocardiographic pulmonary arterial systolic pressure as covariates for predicting mPAP was also strongly associated with invasive mPAP (r=0.89; P <.001).
The areas under the curves for predicting PH were 0.94, 0.90, and 0.92 for predicted mPAP, MPA volume, and echocardiographic pulmonary arterial systolic pressure, respectively. The investigators found that a predicted mPAP of ≥25.8 mm Hg provided the greatest identification of PH. This value was represented with a sensitivity of 86%, specificity of 93%, positive predictive value of 95%, and negative predictive value of 81%.
Limitations of the study include the small patient sample, the retrospective design, and the exclusion of patients with chronic thromboembolic PH.
The researchers concluded that further “[p]rospective studies are warranted to verify the value of the presented technique in the diagnostic workup of patients with suspected PH.”
Melzig C, Wörz S, Egenlauf B, et al. Combined automated 3D volumetry by pulmonary CT angiography and echocardiography for detection of pulmonary hypertension [published online April 8, 2019]. Eur Radiol. doi:10.1007/s00330-019-06188-7