Computed Tomography Assessment of Lung Structure and Function in Pulmonary Edema

Abstract

By definition pulmonary edema is an abnormal accumulation of water in the lung. Consequently, the computed tomography (CT) appearance of pulmonary edema reflects the sequence of this accumulation. In early hydrostatic pulmonary edema, CT shows vascular engorgement and peribronchovascular cuffing that increases with the severity of edema and that is associate in late stage, with consolidations. In acute respiratory distress syndrome (ARDS), CT shows the proportion of injured parenchyma and depicts associated alterations as parenchymal infiltrate and consolidation, pleural effusion, pneumothorax. These merely morphological findings can be complemented with data from objective CT analysis of the lung parenchyma. Indeed CT can assess lung water noninvasively. Correlated with hydrodynamic parameter, these objective measurements show that the increase of lung density parallels parenchymal fluid overload. These data also show that the occurrence of ground glass opacities can precede the hemodynamic evidence of edema.

Resolution of pulmonary edema with variable mechanical ventilation in a porcine model of acute lung injury

“…The significant decrease in global lung density further supports this conclusion. Scillia et al 20 revealed a significant correlation between CT derived density and EVLW by means of double indicator dilution in a canine OA model; this was confirmed later by Kuzkov et al 21 The single indicator thermodilution determination of EVLW has been validated clinically against the double indicator dilution method 16,22 and has been substantiated in animal studies against gravimetry. [23][24][25] As the PiCCO calculation of EVLW excludes both blood and tissue volumes, we anticipated lower PiCCO derived EVLW values compared with CT determined lung weights, but we expected EVLW to increase as CT lung weight increased with OA injury.…”

Early Lung Computed Tomography Scan after Allogeneic Hematopoietic Stem Cell Transplantation

“…In our cohort, the range of causes of pneumonia during the early phase of allogeneic HSCT was not associated with specific CT signs, except for abnormalities related to invasive fungal infection, such as a nodule with a halo sign. Indeed, a significant proportion of lung CT scan abnormalities were potentially related to prolonged bed rest, such as atelectasis [14], or fluid overloading due to significant fluid administration during conditioning, such as pleural effusion and septa thickening [15]. These 2 latter signs reflect a pulmonary vascular leak that is also consistent with periengraftment syndrome [16].…”

Radiographic appearance of cardiogenic pulmonary oedema in 23 cats

“…The variations in the radiographic appearance of pulmonary oedema observed in the present study may reflect different stages in the development of the lesion at the time of radiography. These stages have been described in experimental dogs with hydrostatic pulmonary oedema (Staub and others 1967, Conhaim 1989, Forster and others 1992, Scillia and others 2004). Initially, oedema fluid leaks into the loose tissue around pulmonary vessels and bronchi, and its radiographic appearance may mimic bronchial wall thickening.…”