Optimized scanning conditions of high resolution CT in the follow-up of pulmonary emphysema.
OBJECTIVE
To address the optimal scanning condition of high resolution computerized tomography from the perspective of minimizing exposed dose.


METHODS
The influence of the electric current, the slice number, and the slice thickness on precise percent ratio of the low attenuation area to whole lung field (LAA%) of chronic obstructive pulmonary disease patients was examined. The standard conditions were 250 mA, 3 slices, 2 mm slice thickness, and a varied parameter.


RESULTS
In cases showing an LAA% less than 30, LAA% obtained by < or =150 mA were significantly larger than those by 250 mA. The mean LAA% with 3 and 10 slices were well correlated and the correlation with lung function was similar. The correlation of LAA% with lung function was approximately the same between the 2 and 5 mm slice thicknesses.


CONCLUSIONS
The electrical current must be > or =200 mA, and 3 slices and 2 mm slice thickness are appropriate.
Mishima
M
M
Department of Physical Therapeutics, Kyoto University Hospital, and Institute for Frontier Medical Science, Japan.
Itoh
H
H
Sakai
H
H
Nakano
Y
Y
Muro
S
S
Hirai
T
T
Takubo
Y
Y
Chin
K
K
Ohi
M
M
Nishimura
K
K
Yamaguchi
K
K
Nakamura
T
T
D004560:Electricity; D005500:Follow-Up Studies; D006801:Humans; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000473:pathology; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000009:adverse effects* / Q000295:instrumentation