A new method of CT for the cardiac measurement: correlation of computed tomography measured cardiac parameters and pulmonary obstruction index to assess cardiac morphological changes in acute pulmonary embolism patients.

Acute pulmonary embolism (APE) is a serious disease which is life-threatening. Since it is crucial for APE patients to assess the changes of cardiac function safely and timely, the imaging research of cardiac morphology and function is becoming more and more important. The correlation of computed tomography (CT) measured cardiac parameters and pulmonary obstruction index (POI) was analyzed to discuss the morphological changes of the heart of APE patients in order to provide a new method to evaluate cardiac functions accurately and effectively. 118 APE patients confirmed with CT pulmonary angiography (CTPA) were divided into high-risk group (47 cases, POI ≥ 20) and low-risk group (71 cases, POI < 20) according to the Qanadli Score. The left to right diameter (RL) and the anteroposterior diameter (AP) of the cardiac chambers were compared among the high-risk group, the low-risk group, and the normal group (60 cases). The correlation between CT measured cardiac parameters and the POI was analyzed. Except for left ventricular AP and right atrial AP, there were statistically significant differences (P < 0.05) in the RL and AP of the each cardiac cavity, these parameters meant that right hearts were enlarged and the left hearts were decreased in size. The ratio of right/left heart diameter was statistically significant among the three groups, a < b < c (P < 0.05). Moreover, the POI of 118 APE patients was 14.29 ± 9.53, and there was significant linear correlation between CT measured cardiac parameters and the POI (P < 0.05), excluding the left ventricular AP and right atrial AP. The correlation coefficient reached 0.5 or more in terms of the right atrial LR, the right ventricular LR, the ratio of right/left atrial diameter and the ratio of right/left ventricular diameter. With the increasing value of POI, the right atrium and right ventricular of APE patients were enlarged, and the left atrium and left ventricular were decreased in size. These heart changes can be observed by using CTPA, even non-enhanced chest CT.