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Pulmonary Blood Flow Measurement Using Low-Dose Computed Tomography

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Y Zhao

Y Zhao*, L Hubbard , s malkasian , P Abbona , S Molloi , University of California, Irvine, CA


TH-CD-601-9 (Thursday, August 3, 2017) 10:00 AM - 12:00 PM Room: 601

Purpose: To develop clinically viable strategies for the quantitative measurement of pulmonary blood flow(PBF) from a low-dose dynamic computed tomography (CT), for diagnosis and management of chronic obstructive pulmonary disease (COPD), pulmonary hypertension, and pulmonary embolism.

Methods: An angioplasty balloon was placed in a branch of the left pulmonary artery of six swine (40-50 kg) and dragged from distal to proximal position under fluoroscopic guidance to induce several levels of embolism via balloon inflation. Reference fluorescence microspheres and intravenous contrast (370 mg/mL iodine, 25 mL, 5 mL/s) were injected centrally and dynamic images were acquired using a 320-slice CT scanner at 100 kVp and 400 mA. Over thirty volume scans were acquired per embolism position to capture complete aortic pulmonary enhancement curves, but only two volume scans were used for dynamic FPA PBF measurement. To validate the perfusion measurements, 8-10 tissue samples were segmented out from all different lobes of the entire lung and the mean perfusion in each sub-region were compared to the reference microsphere perfusion measurements using linear regression and concordance correlation.

Results: The result of dynamic FPA PBF measurement was closely correlated with the reference microsphere measurement (PPBF = 0.6124PMICRO + 2.3503, R = 0.8512) on a voxel-by-voxel basis under the balloon occlusion. The occluded regions from different lobes could be easily seen in the CT perfusion map. The root mean square error (RMSE) and difference (RMSD) for the measurements were calculated to be 0.76 mL/min/g and 0.38 mL/min/g, respectively. The effective dose of the proposed technique using two-volume scan acquisition protocol PBF was 2.6 mSv; much lower than the ~6 mSv effective dose of current dynamic PBF techniques alone.

Conclusion: The results indicate the potential for significant improvements in pulmonary disease assessment through low-dose, quantitative dynamic FPA-PBF measurement. Such improvements are afforded through CT scanning technology.

Funding Support, Disclosures, and Conflict of Interest: Grant funding from Toshiba America Medical Systems.

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