Objective: To determine the ability to assess the presence and extent of panacinar emphysema with CT, two chest radiologists independently reviewed CT of 10 patients with pathologically proven panacinar emphysema and five normal controls.
Materials and methods: Six of 15 cases had conventional 10 mm collimation CT, eight cases had conventional CT and high-resolution CT (HRCT), and one case had HRCT only. In each of the 15 cases a single CT image was compared with the inflated pathologic specimen cut in the transverse plane at the same level as the CT scan. Comparison was made between visual assessment of the severity of panacinar emphysema on CT and pathologic assessment of severity using the modified Thurlbeck panel score.
Results: The correlation between the assessment of extent of panacinar emphysema on CT and the pathologic grade was r = 0.90, p < 0.01 for conventional CT and r = 0.96, p < 0.01 for HRCT. There was less interobserver variation in the grading of emphysema on HRCT (mean 0.6, SD 3.9) than with conventional CT (mean 3.9, SD 11.0). Conventional CT correctly identified or excluded panacinar emphysema in 10 of 14 cases, whereas HRCT was correct in 6 of 9 cases.
Conclusion: We conclude that HRCT allows improved correlation with the pathologic score and decreased interobserver variation than conventional CT in panacinar emphysema. However, emphysema may be missed on both techniques.