X-ray Manifestations of Ventricular Septal Defect. These are mainly related to the size of the defect. If the ventricular septal defect is relatively small, for example less than three millimeters, the amount of blood shunted from the left ventricle to the right ventricular system is minimal. Consequently, right ventricular congestion is not pronounced, making pulmonary congestion also less obvious. At this point, the X-ray may show no significant changes. However, if the defect is larger, greater than three millimeters, for instance five millimeters, a large volume of high-pressure blood from the left ventricle will flow excessively through the defect into the right ventricular system. This leads to significant congestion in the right ventricle and, thus, in the entire pulmonary circulation. Additionally, the X-ray will show a prominent pulmonary artery segment and increased pulmonary blood flow. Moreover, over time, this condition may lead to compensatory enlargement of the left ventricular system. On the X-ray, enlargement of both the right and left ventricles can be observed. Furthermore, due to sustained high pressure, the distal pulmonary arteries may show signs of severe pulmonary vascular disease on the X-ray, resembling a broken book. This indicates that the pulmonary circulation has reached an end-stage condition.