Program Information
Reducing Patient Respiration Induced 4DCT Image Artifacts
J Bayouth1*, T Patton1 , S Gerard2 , G Christensen2 , A Baschnagel1 , J Reinhardt2 , (1) University of Wisconsin, Madison, WI, (2)University of Iowa, Iowa City, IA
Presentations
SU-K-605-9 (Sunday, July 30, 2017) 4:00 PM - 6:00 PM Room: 605
Purpose: Artifacts are common in 4D computed tomography (4DCT), the majority of artifacts are caused by variation in patient’s respiratory pattern during image acquisition. We hypothesize patient compliance to a consistent respiratory pattern can be achieved through audio guidance.
Methods: Thirteen subjects were accrued to an IRB approved prospective clinical trial, where retrospectively reconstructed, helical 4DCT scanning was performed on a Siemens Edge CT scanner (Siemens Medical Solutions). The external respiratory surrogate was an infrared reflective block (RPM, Varian). Subjects were instructed to follow a musical melody with breathing instructions directing them to breath in and breath out; the melody and voice instruction was set to 12.5- 13 breaths per minute (bpm). Each trace was recorded for > 60 seconds during the acquisition of the 4DCT scan. Two 4DCT scans were acquired for each subject. Their compliance to the directed respiratory pattern was determined taking the Fourier transform of the RPM signal and calculating the mean period of respiration, the amplitude of respiratory peaks and valleys, the most common breathing frequency, and the percent time spent at that frequency. The results from these subjects were compared to 26 non-instructed 4DCT subjects. Finally, their 4DCT images were reviewed for motion artifacts > 3 mm.
Results: The respiratory patterns of subjects who received audio guidance were significantly more consistent then the non-instructed group. The most common BPM (12.85+/-0.33 vs. 16.12 +/- 5.8), percent time at that BPM (36% vs 18%), mean period (sec) and its coefficient of variation (4.66+/-0.08 vs. 4.06+/-0.33) and (0.06 vs. 0.18), max/mean amplitude (1.2+/- 0.1 vs. 2.5+/-1.9), and min/mean amplitude (0.8+/-0.2 vs. 0.1+/-0.9) were all statistically significant (p<0.01). The motion-induced 4DCT imaging artifacts in this audio guidance group substantially lower.
Conclusion: Musical melody and voice instruction guidance improved 4DCT imaging for this cohort of subjects.
Funding Support, Disclosures, and Conflict of Interest: NIH Grant number R01 CA166703
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