CT lung densitometry in young adults with alpha-1-antitrypsin deficiency.
BACKGROUND
Severe (PiZZ) and moderate (PiSZ) alpha-1-antitrypsin (AAT) deficiency predispose to lung emphysema, especially in smokers. We hypothesized that multi-slice computed tomography (CT) might be superior to pulmonary function tests (PFT) to detect lung emphysema in AAT-deficient individuals at the age of 32 years.


METHODS
A subgroup of PiZZ and PiSZ individuals identified during the Swedish newborn screening programme in 1972-74 underwent multi-slice CT and PFT at the age of 32 years. From the CT scans the percentile density at 15% (PD(15)) and the relative area below -910 Hounsfield Units (RA(-910) HU) were calculated. The results of PFT and CT were compared between the AAT-deficient individuals and an age-matched control group.


RESULTS
Twenty-five PiZZ, 11 PiSZ and 17 PiMM individuals participated in the study. All Pi subgroups had normal lung function. The mean PD(15) was 81 (SD 22) g/L in the PiZZ individuals, 96 (SD 35) g/L in the PiSZ individuals and 79 (SD 17) g/L in the PiMM individuals (ns), and the RA-910 were 30 (SD 18)%, 24 (SD 20)%, and 32 (SD 18)%, respectively (ns). For the never-smoker subgroups, in the PiZZ (n = 23), PiSZ (n = 8) and PiMM (n = 12), the mean PD(15) were 95 (SD 35) g/L, 81 (SD 22) g/L, and 75 (SD 12) g/L, respectively (ns). PD(15) was significantly correlated to CT derived lung size (r = -0.72; p < 0.001).


CONCLUSIONS
CT densitometry revealed no signs of emphysema and no differences between the AAT-deficient individuals identified by neonatal screening and age-matched control subjects.
Bernspång
Elisabeth
E
Department of Emergency Medicine, University Hospital, Uppsala, Sweden. elisabeth.bernspang@med.lu.se
Diaz
Sandra
S
Stoel
Berend
B
Wollmer
Per
P
Sveger
Tomas
T
Piitulainen
Eeva
E
D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D012129:Respiratory Function Tests; D012907:Smoking / Q000009:adverse effects*; D013548:Sweden; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity / Q000502:physiology; D019896:alpha 1-Antitrypsin Deficiency / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology