General surgeons, orthopedists, and pulmonologists individually treat patients with
thoracic insufficiency syndrome (TIS). The benefits of growth-sparing procedures such
as Vertical Expandable Prosthetic Titanium Rib (VEPTR)insertion for treating patients
with TIS have been demonstrated. However, at present there is no objective assessment
metricto examine different thoracic structural components individually as to their
roles in the syndrome, in contributing to dynamics and function, and in influencing
treatment outcome. Using thoracic dynamic MRI (dMRI), we have been developing a methodology
to overcome this problem. In this paper, we extend this methodology from our previous
structural analysis approaches to examining lung tissue properties. We process the
T2-weighted dMRI images through a series of steps involving 4D image construction
of the acquired dMRI images, intensity non-uniformity correction and standardization
of the 4D image, lung segmentation, and estimation of the parameters describing lung
tissue intensity distributions in the 4D image. Based on pre- and post-operative dMRI
data sets from 25 TIS patients (predominantly neuromuscular and congenital conditions),
we demonstrate how lung tissue can be characterized by the estimated distribution
parameters. Our results show that standardized T2-weighted image intensity values
decrease from the pre- to post-operative condition, likely reflecting improved lung
aeration post-operatively. In both pre- and post-operative conditions, the intensity
values decrease also from end-expiration to end-inspiration, supporting the basic
premise of our results.
