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The Effect of Dose Reduction On the Accuracy of First-Pass Analysis Dynamic CT Myocardial Perfusion Measurement
L Hubbard*, S Malkasian , B Dertli , J Kwon , P Abbona , S Molloi , University of California, Irvine, CA
Presentations
SU-K-201-2 (Sunday, July 30, 2017) 4:00 PM - 6:00 PM Room: 201
Purpose: To evaluate the effect of dose reduction on the accuracy of first-pass analysis (FPA) dynamic CT myocardial perfusion (CTP) measurement.
Methods: The effect of mAs reduction on the accuracy of a previously validated FPA dynamic CTP technique was assessed in a swine (50 - 90 kg) animal model. Contrast was injected peripherally (370 mg/mL iodine, 1 mL/kg, 5 mL/s), followed by a saline chaser (0.5 mL/kg, 5 mL/s), and whole-heart volume scans were dynamically acquired under baseline conditions using a 320-slice CT scanner at 100 kVp and 70.0, 52.5, 35.0, 17.5, 8.8, and 3.5 mAs. Diastolic-phase volume scans were reconstructed using AIDR 3D, and FPA dynamic CTP was computed for each acquisition. All acquisitions were then quantitatively compared, with the 70.0 mAs acquisition used as the reference standard for myocardial perfusion. The effective dose per volume scan was also estimated as a function of mAs.
Results: The result of FPA dynamic CTP at 52.5, 35.0, and 17.5mAs was in good agreement with reference standard FPA dynamic CTP at 70 mAs and image noise increased by 4.8%, 11.9% and 25.2%, respectively. The image quality of FPA dynamic CTP at 8.8 and 3.5 mAs was poor and the image noise increased by 40.0% and 62.5%, respectively. The effective dose per volume scan for the 70.0, 52.5, 35.0, 17.5, 8.8, and 3.5 mAs acquisitions was estimated to be 1.0, 0.76, 0.49, 0.24, 0.12, and 0.05 mSv, respectively.
Conclusion: The results indicate the potential for dose reduction in FPA dynamic CTP. Specifically, by reducing the mAs from 70.0 to 17.5 and by using AIDR 3D reconstruction, a three-fold reduction in effective dose is feasible, while maintaining measurement accuracy and adequate image quality.
Funding Support, Disclosures, and Conflict of Interest: Grant funding from Toshiba America Medical Systems.
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