Fig. 4.

In a 67-yr-old female severe asthmatic subject, qualitative evaluation of delayed filling and wash-out is demonstrated by regions of both delayed filling and delayed wash-out in three different coronal reformats from three different subjects. A: regions of filling and washout for the first and last time points postinhalation. B: apical portions of the lung shown depict many regions of delayed filling, with a few regions of interest highlighted by arrows. C: large region in the lower right lung, highlighted by an arrow, is initially hyperintense and shows a delayed washing out of the signal over 7.5 s.