Ventilated postmortem computed tomography to evaluate the lungs of dogs with and without focal lung lesions

To identify the optimal ventilation pressure for ventilated postmortem CT assessment of the lungs in cadaveric dogs and compare the optimal ventilation pressures between dogs with and without focal lung lesions.

12 cadaveric dogs.

CT was performed with dogs positioned in sternal recumbency within 30 to 180 minutes after death. After orotracheal intubation, lungs were aerated to ventilation pressures of 0, 10, 15, 20, 25, 30, and 35 cm H₂O. Lung attenuation measurements were made at 5 predetermined anatomical locations with use of a multi-image analysis graphic user interface tool. Lungs were considered hyperaerated (-1000 to -901 HU), normo-aerated (-900 to -501 HU), poorly aerated (-500 to -101 HU), and nonaerated (-100 to 100 HU) on the basis of lung attenuation values. Optimal ventilation pressure was defined as the pressure at which the percentage of normo-aerated lung was greatest. For analysis, dogs were assigned to one group when focal lung lesions were evident and to another group when lesions were not evident.

Median optimal ventilation pressure was significantly higher for those dogs with lung lesions (35 cm H₂O), compared with those without (25 cm H₂O).

A ventilation pressure of 35 cm H₂O may be considered for ventilated postmortem CT to determine the presence of focal lung lesions; however, further investigation is required.