Does HRCT-emphysema index represent the entire lung?

• Published in: RöFo : Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebende Verfahren Vol. 177; no. 5; p. 655
• Main Authors: Achenbach, T, Buschsieweke, C, Gerhards, A, Gast, K, Heussel, C P, Thelen, M
• Format: Journal Article
• Language: German
• Published: Germany 01-05-2005
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Algorithms; Anatomy, Cross-Sectional - methods; Emphysema - classification; Emphysema - diagnostic imaging; Female; Humans; Imaging, Three-Dimensional - methods; Information Storage and Retrieval - methods; Lung - diagnostic imaging; Male; Middle Aged; Radiographic Image Enhancement - methods; Radiographic Image Interpretation, Computer-Assisted - methods; Reproducibility of Results; Retrospective Studies; Sensitivity and Specificity; Severity of Illness Index; Tomography, X-Ray Computed - methods
• ISSN: 1438-9029
• DOI: 10.1055/s-2005-858101

: Comparison of emphysema index derived of thin section MD-CT of the entire lung volume and HRCT, simulated by calculation of every twentieth image of the whole data-set.
Pulmonary emphysema was quantified by semiautomatic, segmentation of lung borders and assessment of lung volume and emphysema volume within these borders. The emphysema index (pixel index) was calculated. Statistical analysis was done by the sign-test and Bland-Altman-analysis.
Median lung volume, emphysema volume and emphysema index are significantly higher in simulated HRCT. Median lung volume (emphysema volume) calculated by HRCT is 5118 ml (407 ml) and 5040 ml (367 ml) calculated by the entire MD-CT data-set, representing differences of 1 and 8 % related to the median lung and emphysema volumes. Emphysema index is 0.09 (HRCT) and 0.08 (MD-CT).
HRCT overrates emphysema index compared to thin section MD-CT of the entire lung volume.