Abstract
Purpose
The authors assessed the reproducibility of multidetector-row computed tomography (MDCT) volumetry of the total and emphysematous parenchyma of pulmonary lobes.
Materials and methods
Two observers analyzed 23 MDCT examinations of patients with emphysema during two sessions held 3 months apart. Both lungs and all lobes were delimited by a combination of semiautomated and manual segmentation. Emphysematous parenchyma was obtained by applying density thresholds of −1,024/−950 HU. To assess the reproducibility of total volume (V), volume of emphysema (VE) and emphysema index (EI), intra- and interobserver differences of those measurements were assessed.
Results
Total volumetry of the lungs was highly reproducible (intra- and interobserver variability of ±3.4%). Variability between measurements was slightly greater or emphysema volume and index (EI). Lobar analyses showed large ranges of intra- and interobserver variability (intraobserver V=±3.7%–10.6%; VE=±17.3%–32.9%; EI=±17.8%–34%; interobserver V=±13.3%–98.3%; VE=±11%–137.6%; EI=±28.9%–96.4%).
Conclusions
MDCT quantification of total and emphysematous lung volume and emphysema index is overall reproducible. Quantitative assessment of those parameters performed on single lobes is affected by variability. An improvement of the reproducibility of q-MDCT is expected from the use of advanced methods for lobar segmentation.
Riassunto
Obiettivo
Lo scopo del nostro studio è stato quello di valutare la riproducibilità della volumetria in tomografia computerizzata multidetettore (MDTC) del parenchima polmonare lobare totale ed enfisematoso.
Materiali e metodi
In due sessioni a distanza di tre mesi, due operatori hanno analizzato 23 esami MDTC del torace di pazienti con enfisema polmonare. Con una procedura semiautomatica e manuale sono stati delimitati i due polmoni ed i lobi. Il parenchima enfisematoso è stato ottenuto applicando un range densitometrico di −1024/−950 unità Hounsfield (HU). La riproducibilità del volume totale (V), d’enfisema (VE) e dell’indice d’enfisema (EI) è stata valutata calcolando le differenze intra- ed interosservatore tra le misurazioni.
Risultati
La volumetria totale per polmoni è risultata complessivamente riproducibile, con variabilità intra- ed interossevatore tra le misurazioni di ±3,4%. La variabilità tra le misurazioni è stata lievemente maggiore per il volume e l’indice d’enfisema. Le volumetrie lobari hanno presentato range di variabilità maggiori nell’analisi intraosservatore e nettamente superiori in quella interosservatore (intra-osservatore: V=±3,7%–10,6%; VE=±17,3%–32,9%; EI=±17,8%–34%; interosservatore: V=±13,3%–98,3%; VE=±11%–137,6%; EI=±28,9%–96,4%).
Conclusioni
La quantificazione MDTC del volume polmonare totale, della frazione d’enfisema e dell’indice d’enfisema è complessivamente riproducibile. Sui singoli lobi, l’analisi volumetrica presenta maggiore variabilità. Ai fini dell’applicazione clinica, l’impiego di software per la segmentazione automatica potrà fornire valori di riproducibilità migliori per la volumetria MDTC quantitativa lobare.
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Molinari, F., Amato, M., Stefanetti, M. et al. Density-based MDCT quantification of lobar lung volumes: a study of inter- and intraobserver reproducibility. Radiol med 115, 516–525 (2010). https://doi.org/10.1007/s11547-010-0536-x
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DOI: https://doi.org/10.1007/s11547-010-0536-x