The use of high-resolution computed tomography in the evaluation of pulmonary hemodynamics in patients with congenital heart disease: In pulmonary vessels larger than 1 mm in diameter

High-resolution computed tomography (HRCT) was carried out in 36 patients w ith congenital left-to-right shunt disease and 10 normal control subjects t o assess the feasibility of CT in the evaluation of pulmonary hemodynamics. The patients had a left-to-right or a bidirectional shunt and the hemodyna mic data obtained by cardiac catheterization in these patients were compare d to the information obtained by CT imaging. The pulmonary/systemic blood f low (Q(p)/Q(s)) ratio and pulmonic/systemic resistance (R-p/R-s) ratio had a significant correlation with the pulmonary artery/bronchus (PA/Br) ratio (r = 0.54 and r = -0.37, respectively) and pulmonary vein/bronchus (PV/Br) ratio (r = 0.56 and r = -0.66, respectively), and the R-p/R-s and mean PA p ressure also showed a significant correlation with the PA/ PV ratio (r = 0. 53 and r = -0.61, respectively) in the mid-lung field when accompanying bro nchi were 4.0-5.9 mm in diameter. There was no correlation between the hemo dynamic data and the size of the central and hilar PA or with the rate of P A tapering. With HRCT, it is possible to evaluate pulmonary hemodynamics in patients with congenital heart disease with a left-to-right or bidirection al shunt, particularly R-p/R-s and mean PA pressure, which have been very d ifficult to obtain noninvasively. The small-sized pulmonary vessel/Br ratio or the small-sized PA/PV ratio could offer very useful information, but th e dimension of the central PA provided the least useful information.