Density-mask spiral computed tomography in patients who are candidates for a lung-volume-reduction intervention: a preliminary study

PURPOSE: To investigate the usefulness of helical CT with multiplanar reconstructions and density mask in emphysematous patients candidate for lung volume reduction surgery (LVRS), in order to assess the feasibility of surgery and for surgical planning. MATERIAL AND METHODS: Twenty emphysematous patients (5 women and 15 men; age range: 55-67 years, mean: 61) candidate for LVRS were submitted to isotope perfusion scanning, chest radiography during maximal inspiration and expiration and Helical CT with the low volume contrast technique, multiplanar reconstructions and density mask. RESULTS: Only 8 of the 20 patients examined were submitted to LVRS. They had irregular distribution of emphysema at isotope perfusion scanning and density mask CT. Surgery consisted in an atypical resection of the upper lobe portions which appeared most damage with both techniques. Six of the remaining 12 nonsurgical patients were excluded because of homogeneous distribution of emphysema at both CT and perfusion scanning, which was incompatible with surgery. Lung transplant was considered for 4 of these patients, but only 2 of them actually received it. Three patients were excluded from LVRS because of excessive diaphragm excursion during expiration at chest radiography and of multiple confluent areas of emphysema in both lung at CT and perfusion scanning. One patient with a large area of emphysema in the right upper lobe at CT and perfusion scanning was excluded due to associated severe interstitial disease. Another patient with emphysema mainly involving the lower lobes, as clearly depicted with both techniques, was excluded because the emphysema was secondary to alpha 1-antitrypsin deficiency, a condition known to have a less favorable surgical outcome. Finally, one patient was excluded due to a previous upper transverse laryngectomy, although CT and perfusion scanning patterns were compatible with surgery. CONCLUSIONS: In our opinion, density mask helical CT yields more accurate and clearer images than perfusion scanning, and allows the patients candidate for surgery to undergo a single examination to evaluate the extent and distribution of emphysema and to detect other possible pathological conditions. Though ours was a small series, the results suggest that perfusion scanning be integrated with density mask helical CT, the latter a very important technique for surgical planning.