Archiv - Dezember 2010

Künstlich beatmete Patienten – Beurteilung der Schwere der Lungenschädigung

In der vorliegenden Arbeit wurde untersucht, ob die Analyse von nur zehn gleichmäßig über die Lunge angeordneten CT-Bildern zuverlässige Informationen über die Belüftung und damit über die Erkrankung der gesamten Lunge liefern kann (bisher kamen 50 und mehr CT-Bilder zur Auswertung). Die Übereinstimmung zwischen den Werten aus der Extrapolationsmethode (zehn CT-Bilder) und der bisher verwendeten Methode (Referenz, alle CT- Bilder) war exzellent. Mithilfe der Extrapolationsmethode können nun aus CTs gewonnene Informationen einfacher zur Therapie-Steuerung bei Patienten mit einem Lungenversagen eingesetzt werden.

Extrapolation from ten sections can make CT-based quantification of lung aeration more practicable.

Reske AW, Reske AP, Gast HA, Seiwerts M, Beda A, Gottschaldt U, Josten C, Schreiter D, Heller N, Wrigge H, Amato MB.

Intensive Care Med. 2010 Nov;36(11):1836-44.

PURPOSE: Clinical applications of quantitative computed tomography (qCT) in patients with pulmonary opacifications are hindered by the radiation exposure and by the arduous manual image processing. We hypothesized that extrapolation from only ten thoracic CT sections will provide reliable information on the aeration of the entire lung.

METHODS: CTs of 72 patients with normal and 85 patients with opacified lungs were studied retrospectively. Volumes and masses of the lung and its differently aerated compartments were obtained from all CT sections. Then only the most cranial and caudal sections and a further eight evenly spaced sections between them were selected. The results from these ten sections were extrapolated to the entire lung. The agreement between both methods was assessed with Bland-Altman plots.

RESULTS: Median (range) total lung volume and mass were 3,738 (1,311-6,768) ml and 957 (545-3,019) g, the corresponding bias (limits of agreement) were 26 (-42 to 95) ml and 8 (-21 to 38) g, respectively. The median volumes (range) of differently aerated compartments (percentage of total lung volume) were 1 (0-54)% for the nonaerated, 5 (1-44)% for the poorly aerated, 85 (28-98)% for the normally aerated, and 4 (0-48)% for the hyperaerated subvolume. The agreement between the extrapolated results and those from all CT sections was excellent. All bias values were below 1% of the total lung volume or mass, the limits of agreement never exceeded ± 2%.

CONCLUSION: The extrapolation method can reduce radiation exposure and shorten the time required for qCT analysis of lung aeration.

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