Perfusion lung scintigraphy for the prediction of postlobectomy residual pulmonary function

Scintigraphic prediction of the residual pulmonary function following a lobectomy is not widely employed; its accuracy is poorly known. This study aims at determining the accuracy and the clinical value of the scintigraphic prediction of postlobectomy residual function.

In this study, 41 patients with bronchial carcinoma underwent a perfusion lung scintigraphy before lobectomy; the functional contribution of each single lobe was computed by an indirect method proposed by Wernly et al.; the results of the scintigraphic prediction were compared with those of the pulmonary function tests performed 1 month after surgery.

The linear regression analyses of predicted and observed values of FVC and FEV1 showed significant correlations (R2=0.607 and 0.749, respectively); however, an evident scatter of data was obtained, as quantified by the values of imprecision (20.70% and 18.11%, respectively) and global inaccuracy (25.50% and 22.90%, respectively). The estimates of both FVC and FEV1 were significantly better in right lung lobectomies than in left lung lobectomies (mean imprecision and global inaccuracy: 15.43% and 14.94% for the right lung, and 27.27% and 29.00% for the left lung).

The scintigraphic prediction of postlobectomy residual function is easily implemented by the method herein employed; it has a greater margin of uncertainty than that of pneumonectomy, especially for left lobectomies; however, the use of some safety thresholds for predicted values of FEV1 (1.2 L for upper lobectomies and 1 L for lower lobectomies) guarantees a safe clinical use of the test.