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Effects of contrast material on computed tomographic measurements of lung volumes in patients with acute lung injury.

Bouhemad B, Richecoeur J, Lu Q, Malbouisson LM, Cluzel P, Rouby JJ, ARDS CT Scan Study Gro - Crit Care (2002)

Bottom Line: The maximal artifactual increase in lung tissue resulting from a hypothetical leakage within the lung of the 80 ml contrast material was calculated.Injection of contrast material significantly increased the apparent volume of lung tissue by 83 +/- 57 ml in group 1 and 102 +/- 80 ml in group 2, whereas the corresponding maximal artifactual increases in lung tissue were 42 +/- 52 ml and 31 +/- 18 ml.Because systematic injection of contrast material increases the amount of extravascular lung water in patients with acute lung injury, it seems prudent to avoid this procedure in critically ill patients undergoing a thoracic CT scan and to reserve its use for specific indications.

View Article: PubMed Central - PubMed

Affiliation: Clinique en Réanimation Chirurgicale Pierre Viars (Department of Anaesthesiology), Hospital Pitié-Salpêtrière, University of Paris VI, Paris, France.

ABSTRACT

Background: Intravenous injection of contrast material is routinely performed in order to differentiate nonaerated lung parenchyma from pleural effusion in critically ill patients undergoing thoracic computed tomography (CT). The aim of the present study was to evaluate the effects of contrast material on CT measurement of lung volumes in 14 patients with acute lung injury.

Method: A spiral thoracic CT scan, consisting of contiguous axial sections of 10 mm thickness, was performed from the apex to the diaphragm at end-expiration both before and 30 s (group 1; n = 7) or 15 min (group 2; n = 7) after injection of 80 ml contrast material. Volumes of gas and tissue, and volumic distribution of CT attenuations were measured before and after injection using specially designed software (Lungview; Institut National des Télécommunications, Evry, France). The maximal artifactual increase in lung tissue resulting from a hypothetical leakage within the lung of the 80 ml contrast material was calculated.

Results: Injection of contrast material significantly increased the apparent volume of lung tissue by 83 +/- 57 ml in group 1 and 102 +/- 80 ml in group 2, whereas the corresponding maximal artifactual increases in lung tissue were 42 +/- 52 ml and 31 +/- 18 ml.

Conclusion: Because systematic injection of contrast material increases the amount of extravascular lung water in patients with acute lung injury, it seems prudent to avoid this procedure in critically ill patients undergoing a thoracic CT scan and to reserve its use for specific indications.

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Related in: MedlinePlus

Individual percentage of changes in the apparent volume of lung tissue 30 s and 15 min after injection of 80 ml contrast material in patients in group 1 (upper panel) and group 2 (lower panel). The horizontal line indicates the mean value of the apparent volume of lung tissue. Blacks bars represent individual percentage of maximum artifactual increase in lung tissue calculated according to the hypothesis that the 80 ml of contrast material penetrated into the alveolar–interstitial space and formed an interface with the alveolar gas.
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Figure 3: Individual percentage of changes in the apparent volume of lung tissue 30 s and 15 min after injection of 80 ml contrast material in patients in group 1 (upper panel) and group 2 (lower panel). The horizontal line indicates the mean value of the apparent volume of lung tissue. Blacks bars represent individual percentage of maximum artifactual increase in lung tissue calculated according to the hypothesis that the 80 ml of contrast material penetrated into the alveolar–interstitial space and formed an interface with the alveolar gas.

Mentions: As shown in Fig. 3, the individual increase in lung tissue volume was variable from one patient to another, ranging from 2% to 20% and with mean changes of 8 ± 6% in group 1 and 7 ± 5% in group 2. Thirty seconds after the injection, the maximal artifactual increase in lung tissue represented 39 ± 35% of the apparent increase in lung tissue (extremes 0 and 85%). Fifteen minutes after the injection, the maximal artifactual increase in lung tissue represented 45 ± 43% of the apparent increase in lung tissue (extremes 6 and 100%).


Effects of contrast material on computed tomographic measurements of lung volumes in patients with acute lung injury.

Bouhemad B, Richecoeur J, Lu Q, Malbouisson LM, Cluzel P, Rouby JJ, ARDS CT Scan Study Gro - Crit Care (2002)

Individual percentage of changes in the apparent volume of lung tissue 30 s and 15 min after injection of 80 ml contrast material in patients in group 1 (upper panel) and group 2 (lower panel). The horizontal line indicates the mean value of the apparent volume of lung tissue. Blacks bars represent individual percentage of maximum artifactual increase in lung tissue calculated according to the hypothesis that the 80 ml of contrast material penetrated into the alveolar–interstitial space and formed an interface with the alveolar gas.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC154113&req=5

Figure 3: Individual percentage of changes in the apparent volume of lung tissue 30 s and 15 min after injection of 80 ml contrast material in patients in group 1 (upper panel) and group 2 (lower panel). The horizontal line indicates the mean value of the apparent volume of lung tissue. Blacks bars represent individual percentage of maximum artifactual increase in lung tissue calculated according to the hypothesis that the 80 ml of contrast material penetrated into the alveolar–interstitial space and formed an interface with the alveolar gas.
Mentions: As shown in Fig. 3, the individual increase in lung tissue volume was variable from one patient to another, ranging from 2% to 20% and with mean changes of 8 ± 6% in group 1 and 7 ± 5% in group 2. Thirty seconds after the injection, the maximal artifactual increase in lung tissue represented 39 ± 35% of the apparent increase in lung tissue (extremes 0 and 85%). Fifteen minutes after the injection, the maximal artifactual increase in lung tissue represented 45 ± 43% of the apparent increase in lung tissue (extremes 6 and 100%).

Bottom Line: The maximal artifactual increase in lung tissue resulting from a hypothetical leakage within the lung of the 80 ml contrast material was calculated.Injection of contrast material significantly increased the apparent volume of lung tissue by 83 +/- 57 ml in group 1 and 102 +/- 80 ml in group 2, whereas the corresponding maximal artifactual increases in lung tissue were 42 +/- 52 ml and 31 +/- 18 ml.Because systematic injection of contrast material increases the amount of extravascular lung water in patients with acute lung injury, it seems prudent to avoid this procedure in critically ill patients undergoing a thoracic CT scan and to reserve its use for specific indications.

View Article: PubMed Central - PubMed

Affiliation: Clinique en Réanimation Chirurgicale Pierre Viars (Department of Anaesthesiology), Hospital Pitié-Salpêtrière, University of Paris VI, Paris, France.

ABSTRACT

Background: Intravenous injection of contrast material is routinely performed in order to differentiate nonaerated lung parenchyma from pleural effusion in critically ill patients undergoing thoracic computed tomography (CT). The aim of the present study was to evaluate the effects of contrast material on CT measurement of lung volumes in 14 patients with acute lung injury.

Method: A spiral thoracic CT scan, consisting of contiguous axial sections of 10 mm thickness, was performed from the apex to the diaphragm at end-expiration both before and 30 s (group 1; n = 7) or 15 min (group 2; n = 7) after injection of 80 ml contrast material. Volumes of gas and tissue, and volumic distribution of CT attenuations were measured before and after injection using specially designed software (Lungview; Institut National des Télécommunications, Evry, France). The maximal artifactual increase in lung tissue resulting from a hypothetical leakage within the lung of the 80 ml contrast material was calculated.

Results: Injection of contrast material significantly increased the apparent volume of lung tissue by 83 +/- 57 ml in group 1 and 102 +/- 80 ml in group 2, whereas the corresponding maximal artifactual increases in lung tissue were 42 +/- 52 ml and 31 +/- 18 ml.

Conclusion: Because systematic injection of contrast material increases the amount of extravascular lung water in patients with acute lung injury, it seems prudent to avoid this procedure in critically ill patients undergoing a thoracic CT scan and to reserve its use for specific indications.

Show MeSH
Related in: MedlinePlus