[Multi-rotation CT during continuous ventilation: comparison of different density areas in healthy lungs and in the ARDS lavage model].
OBJECTIVE
In this animal study, density ranges for CT-based quantification of ventilated lung area were determined. Healthy lungs and ARDS lungs were compared during artificial respiration.


METHODS
CT-scans were performed in 5 anesthetized pigs using a dynamic multiscan CT option on a predefined transverse slice (slice thickness 1 mm; effective temporal resolution, 250 ms). During continuous CT acquisition, airway pressure was increased or decreased in a stepwise manner. In all images, areas of defined HU ranges were determined planimetrically. The lower threshold was set to -910 HE in all images. The upper threshold was varied from -800 HE to -200 HE in steps of 100 HE.


RESULTS
During inspiration in healthy lungs the HU-range of -910 to -700 HU showed the largest increase in area. During inspiration in ARDS lungs the HU range from -910 to -300 HU allowed the most sensitive assessment of area changes. These findings can be explained by recruitment of atelectases (HU-range > -300 HU) and their transition to a HU range from -700 to -300 HU.


CONCLUSIONS
Dynamic multiscan CT acquisitions are a useful method to determine changes of ventilated lung area during a respiratory cycle. Different HU-ranges are required to access volume changes in healthy lungs and in ARDS lungs.
Klinik und Poliklinik für Radiologie, Johannes Gutenberg-Universität Mainz. Klm@mail.uni-mainz.de
K
K
Markstaller
H U
HU
Kauczor
B
B
Eberle
N
N
Weiler
D
D
Siebertz
K
K
Birkenkamp
W
W
Heinrichs
M
M
Thelen
D000818:Animals; D004195:Disease Models, Animal; D012123:Pulmonary Ventilation / Q000502:physiology; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D012984:Software; D013552:Swine; D007507:Therapeutic Irrigation; D014057:Tomography, X-Ray Computed
Multirotations-CT während kontinuierlicher Beatmung: Vergleich unterschiedlicher Dichtebereiche bei gesunden Lungen und im Lavage-ARDS Modell.