Clinical background
A 16 year old girl who suffered from a congenital spinal chord deformation (kyphoscoliosis) was seen at the hospital following complaints of wheezing during deep inhalation. The spirometry tests showed a severely restrictive lung function with a forced expiratory volume in one second of only 57% of the normal value.
Question
The clinical questions were:
- Can imaging and segmentation be used to detect the cause of the wheezing sound?
- Can, based on these findings, an appropriate therapy be selected?
- Can imaging be used to evaluate this therapy?
Imaging and segmentation
At baseline, the patient underwent a low-dose HRCT scan of the thorax taken at total lung capacity (TLC), which is the lung level attained after a deep inhalation. From these images both the airway tree structure and the lobar volumes were segmented and reconstructed in 3D.
Segmentation of the lobar volumes (left) and the airway tree (right) at baseline
The initial segmented images revealed that the right lower lobe was smaller than normal. This could be attributed to the fact the airways towards this lobe were occluded by the deformed spinal chord. This occlusion also caused the wheezing sound during inhalation. The suggested therapy consisted of placing an endobronchial stent to prevent collapse of the airways. To ensure proper placement of the stent, the segmented images were used to select an appropriate stent size and placement location.
Required stent dimensions (left) and airway tree segmentation after stent placement (right)
One month after the placement of the stents a new low-dose HRCT scan was taken and again the airway tree was segmented. The results indicated the airway was reopened successfully and the right lower lobe again received more air. This was confirmed by the measurements of the total lung capacity indicating an increase from 57% to 68% of the normal value.
Conclusions
For this case study, imaging was able to successfully identify the cause of wheezing and assist in proper treatment selection. After the intervention, imaging and segmentation was used to evaluate the therapy. This example illustrates the added value of imaging and in particular segmentation
Mimics Innovation Award
This study was awarded the Mimics Innovation Award in 2007.