Preoperative assessment of relative pulmonary lobar perfusion fraction in lung cancer patients. A rather simple three-dimensional CT-based vs. planar image-derived quantification

Abstract

Preoperative quantification of (relative) pulmonary lobar perfusion fraction using scintigraphy is established in predicting lung function after pulmonary surgery. Aim was to develop an easy and truly anatomical method for relative pulmonary lobar perfusion fraction quantification using SPECT/CT and to compare results with those from planar analyses in lung cancer patients.

Patients, methods: 36 patients with operable lung cancer, borderline lung function referred to pre-operative quantification. Perfusion SPECT-data were acquired p.i. of 163±9 MBq 99mTc-MAA, subsequent low-dose-CT (SymbiaT, Siemens). Iterative Flash3D-reconstruction, manual 3D segmentation of all lobes using PMOD. VOI transfer to coregistered perfusion SPECT-data, calculation of lobar fractions. Model-based calculation of relative lobar fractions based on planar data, analysis of planar vs. 3D results using t-test.

Results: Significant differences (p<0.05) between the results from 3D method and planar imaging were found for right upper and middle lobe and both lower lobes. Maximum differences ranged from 10.9% (left upper lobe) to 22.9% (right upper lobe).

Conclusions: Relative pulmonary lobar perfusion fraction can easily be obtained by an anatomically driven 3D quantification. Results yielded by this method and the traditional planar approach differed greatly, possibly affecting eligibility for lung surgery in individual patients. Considering these results a 3D approach should be used whenever possible.

Keywords: 3D-quantification; Quantitative lung perfusion SPECT/CT; estimated postoperative FEV 1.0; lung cancer.