High resolution computed tomography in asthma

ABSTRACT

High-resolution computed tomography [HRCT] can detect the structural abnormalities in asthma. This study attempts to correlate these abnormalities with clinical and pulmonary function test [PFT] data. Consecutive stable asthma patients attending Mubarak Al Kabeer Hospital, Kuwait, were subjected to HRCT during a six month period from July 2004 to December 2004, after initial evaluation and PFT. Of the 28 cases, sixteen [57.1%] had moderate, 6 [21.4%] had mild and 6 [21.4%] had severe persistent asthma. Thirteen [46.4%] patients had asthma for 1 to 5 years and 12 [42.9%] were having asthma for >10 years. Bronchial wall thickening [57.1%], bronchiectasis [28.6%], mucoid impaction [17.9%], mosaic attenuation [10.7%], air trapping [78.6%] and plate like atelectasis [21.4%] were noted. Bronchial wall thickening [p=0.044] and bronchiectasis [p=0.063] were most prevalent in males. Ten [35.7%] patients exhibited mild, 9 [32.1%] had moderate and 3 [10.7%] had severe air trapping. The difference in Hounsfield units between expiratory and inspiratory slices [air trapping] when correlated with percent-predicted FEV1 in right upper [r=0.25; p=0.30], left upper [r=0.20; p=0.41], right mid [r=0.15; p=0.53], left mid [r=-0.04; p=0.60], right lower [r=0.04; p=0.86] and left lower zones [r=-0.13; p=0.58] showed no relation. The same when correlated as above with the percent predicted FEF 25-75 did not show any significant association. The presence of air trapping was compared with sex [p=0.640], nationality [p=1.000], disease duration [p=1.000] and severity of symptoms [p=0.581]. Abnormal HRCT findings are common in asthma; however, air trapping when present was not related to the duration or severity of the illness or to the FEV1