Importance of carefully interpreting computed tomography images to detect partial anomalous pulmonary venous return

Partial anomalous pulmonary venous return (PAPVR) is characterized by an abnormal connection of the pulmonary vein (PV). The left-to-right shunt results in an increased pulmonary blood flow, which may be followed by developing pulmonary hypertension (PH). We found that computed tomography (CT) scans may be misinterpreted, potentially leaving anomalous PVs undetected when reviewing diagnostic findings of PAPVR patients. The purpose of this study was to delineate this risk and assess the usefulness of our interpretation methods.

We retrospectively reviewed the records of 8 patients diagnosed with PAPVR, diagnosed with right heart catheterization (RHC) findings, at our department between 1991 and 2013. Our CT screening method for assessing anomalous PVs consisted of two points: 1) confirming that four PVs were connected to the left atrium (LA) and 2) checking that the vena cava was not connected with anomalous PVs. The accuracy of this method was analyzed in a blinded manner.

In 4 patients, anomalous PVs delineated on enhanced CT scan images obtained before RHC were undetected. The sensitivity and specificity of detecting PAPVRs using our protocol were 0.800 and 0.978, respectively. Four of 8 patients went on to develop PH. Age at the time of diagnosis was positively correlated with mean pulmonary arterial pressure (r=0.929, p=0.002).

There is a potential risk of CT scan misinterpretation when looking for anomalous PVs. Careful interpretation of CT findings that focus on PVs may be useful for detecting PAPVR and obtaining a PH differential diagnosis.