Original Article
Quantitative computed tomography to predict postoperative FEV1 after lung cancer surgery
Abstract
Background: Predicted postoperative FEV1 (ppoFEV1) must be estimated preoperatively prior to surgery for non-small cell lung cancer (NSCLC). We evaluated a lung volumetry approach based on chest computed tomography (CT).
Methods: A prospective study was conducted over a period of one year in eligible lung cancer patients to evaluate the difference between ppoFEV1 and the 3-month postoperative FEV1 (poFEV1). Patients in whom CT was performed in another hospital and those with factors influencing poFEV1, such as atelectasis, pleural effusion, pneumothorax, or pneumonia, were excluded. A total of 23 patients were included and ppoFEV1 was calculated according to 4 usual Methods: Nakahara formula, Juhl and Frost formula, ventilation scintigraphy, perfusion scintigraphy, and a fifth method based on quantitative CT. Lung volume was calculated twice and separately by 2 radiologists. Tumor volume, and emphysema defined by a −950 HU limit were subtracted from the total lung volume in order to estimate ppoFEV1.
Results: We compared 5 methods of ppoFEV1 estimation and calculated the mean volume difference between ppoFEV1 and poFEV1. A better correlation was observed for quantitative CT than for Nakahara formula, Juhl and Frost formula, perfusion scintigraphy and ventilation scintigraphy with respectively: R²=0.79 vs. 0.75, 0.75, 0.67 and 0.64 with a mean volume difference of 266±229 mL (P<0.01) vs. 320±262 mL (P<0.01), 332±251 mL (P<0.01), 304±295 mL (P<0.01) and 312±303 mL (P<0.01).
Conclusions: Quantitative CT appears to be a satisfactory method to evaluate ppoFEV1 evaluation method, and appears to be more reliable than other approaches. Estimation of ppoFEV1, as part of the preoperative assessment, does not involve additional morphologic examinations, particularly scintigraphy. This method may become the reference method for ppoFEV1 evaluation.
Methods: A prospective study was conducted over a period of one year in eligible lung cancer patients to evaluate the difference between ppoFEV1 and the 3-month postoperative FEV1 (poFEV1). Patients in whom CT was performed in another hospital and those with factors influencing poFEV1, such as atelectasis, pleural effusion, pneumothorax, or pneumonia, were excluded. A total of 23 patients were included and ppoFEV1 was calculated according to 4 usual Methods: Nakahara formula, Juhl and Frost formula, ventilation scintigraphy, perfusion scintigraphy, and a fifth method based on quantitative CT. Lung volume was calculated twice and separately by 2 radiologists. Tumor volume, and emphysema defined by a −950 HU limit were subtracted from the total lung volume in order to estimate ppoFEV1.
Results: We compared 5 methods of ppoFEV1 estimation and calculated the mean volume difference between ppoFEV1 and poFEV1. A better correlation was observed for quantitative CT than for Nakahara formula, Juhl and Frost formula, perfusion scintigraphy and ventilation scintigraphy with respectively: R²=0.79 vs. 0.75, 0.75, 0.67 and 0.64 with a mean volume difference of 266±229 mL (P<0.01) vs. 320±262 mL (P<0.01), 332±251 mL (P<0.01), 304±295 mL (P<0.01) and 312±303 mL (P<0.01).
Conclusions: Quantitative CT appears to be a satisfactory method to evaluate ppoFEV1 evaluation method, and appears to be more reliable than other approaches. Estimation of ppoFEV1, as part of the preoperative assessment, does not involve additional morphologic examinations, particularly scintigraphy. This method may become the reference method for ppoFEV1 evaluation.
