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P. Van Schil



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    P2.07 - Poster Session 2 - Surgery (ID 190)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Surgery
    • Presentations: 1
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      P2.07-040 - Is postoperative FEV1 (poFEV1) more accurately estimated by Functional Respiratory Imaging (FRI) than by conventional methods? (ID 3090)

      09:30 - 09:30  |  Author(s): P. Van Schil

      • Abstract

      Background
      Accurate estimation of poFEV1 remains challenging. Underestimation excludes patients with early stage lung cancer from a potential curative resection, overestimation gives more postoperative complications. The anatomic segment method (ASM) and the perfusion scintigraphy (QS) are standard methods, although both underestimate actual poFEV1 (Holvoet 2011). FRI, describing flow characteristics in the lungs, estimates poFEV1 after virtual resection (De Backer 2010). We compared the accuracy of FRI with ASM and QS in the estimation of poFEV1 in patients planned for resection of lung cancer.

      Methods
      23 consecutive patients underwent pre- and postoperative FEV1 measurements by spirometry, ASM, QS and FRI. ASM-poFEV1 was estimated by the product of preop FEV1 with (1-number of resected segments /19). QS-images were obtained following intravenous injection of 175 MBq of [99m]Tc-MAA, using geometric means method to determine left and right sided contribution. QS-poFEV1 was the product of preop FEV1 x (1- number of resected segments/total number of segments in operated lung x perfusion in this lung). Pneumotach controlled CT scan at maximum expiration (RV) and inspiration (TLC) allowed to segment lobar volumes and calculated regional expansion (EXP). Resistances (iRaw before and after virtual resection) were acquired through computational fluid dynamics. FRI-poFEV1 equation: Figure 1

      Results
      Data of 14 patients are available: 8 male, median age 63 y (51-73), median preop FEV1 2490 ml (1660-4070), 10 lobectomy, 2 bilobectomy, 2 pneumonectomy. Median actual poFEV1 was 2100 ml (1210-3210). The Pearson correlation coefficient (R[2]) paired t-test and root mean square error (RMSE) between actual and predicted poFEV1 are shown below. FRI-poFEV1 underestimated fewer cases with respect to the actual- 7% variation corrected-poFEV1 (Oostveen,2013 in press) than the other methods.

      Method Predicted median poFEV1 (ml) (range) Underestimated cases (n) R[2] Slope RMSE (ml) P (paired t-test)
      ASM 1660 (1240-2970) 11/14 0.77 1.06 436 <0.001
      QS 1980 (1320-3040) 7/14 0.84 1.10 309 0.007
      FRI 2050 (1450-3440) 4/14 0.86 0.98 213 0.76

      Conclusion
      FRI seems a superior predictor of actual poFEV1 in resected lung cancer pts than either conventional method, allowing for 20% more functionally operable patients. Confirmation in a larger serie is ongoing.