Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights. ORIGINAL RESEARCH n TECHNICAL DEVELOPMENTS 854 radiology.rsna.org n Radiology: Volume 257: Number 3—December 2010 Validation of Computational Fluid Dynamics in CT-based Airway Models with SPECT/CT 1 Jan W. De Backer, MSc, PhD Wim G. Vos, MSc Samir C. Vinchurkar, MSc, PhD Rita Claes Anton Drollmann, MD Denis Wulfrank, MD, PhD Paul M. Parizel, MD, PhD Paul Germonpré, MD, PhD Wilfried De Backer, MD, PhD Purpose: To compare the results obtained by using numerical flow simulations with the results of combined single photon emission computed tomography (SPECT) and computed tomography (CT) and to demonstrate the importance of correct boundary conditions for the numerical methods to account for the large amount of interpatient variability in airway geometry. Materials and Methods: This study was approved by all relevant institutional review boards. All patients gave their signed informed consent. In this study, six patients with mild asthma (three men; three women; overall mean age, 46 years 6 17 [standard deviation]) underwent CT at functional residual capacity and total lung capacity, as well as SPECT/CT. CT data were used for segmentation and computational fluid dynamics (CFD) simulations. A comparison was made between air- flow distribution, as derived with (a) SPECT/CT through tracer concentration analysis, (b) CT through lobar expan- sion measurement, and (c) CFD through flow computer simulation. Also, the heterogeneity of the ventilation was examined. Results: Good agreement was found between SPECT/CT, CT, and CFD in terms of airflow distribution and hot spot detection. The average difference for the internal airflow distribution was less than 3% for CFD and CT versus SPECT/CT. Het- erogeneity in ventilation patterns could be detected with SPECT/CT and CFD. Conclusion: This results of this study show that patient-specific com- puter simulations with appropriate boundary conditions yield information that is similar to that obtained with func- tional imaging tools, such as SPECT/CT. q RSNA, 2010 Supplemental material: http://radiology.rsna.org/lookup /suppl/doi:10.1148/radiol.10100322/-/DC1 1 From FluidDA, Groeningenlei 132, 2550 Kontich, Belgium (J.W.D.B., W.G.V., S.C.V.); Departments of Respiratory Medicine (R.C., P.G., W.D.B.) and Radiology (P.M.P.), Univer- sity Hospital Antwerp, Antwerp, Belgium; Novartis, Basel, Switzerland (A.D.); and Department of Nuclear Medicine, AZ Maria Middelares, Ghent, Belgium (D.W.). Received Febru- ary 9, 2010; revision requested April 2; revision received June 21; accepted July 28; final version accepted August 18. Supported by Novartis. Address correspondence to J.W.D.B. (e-mail: Jan.DeBacker@FluidDA.com). q RSNA, 2010