Alexi Otrakji MD, Presenter: Nothing to Disclose

Efren Jesus Flores MD, Abstract Co-Author: Nothing to Disclose

Roberto Lo Gullo MD, Abstract Co-Author: Nothing to Disclose

Subba Rao Digumarthy MD, Abstract Co-Author: Nothing to Disclose

Jo-Anne O. Shepard MD, Abstract Co-Author: Consultant, Agfa-Gevaert Group

Mannudeep K. S. Kalra MD, Abstract Co-Author: Nothing to Disclose

Matthew David Gilman MD, Abstract Co-Author: Nothing to Disclose

To evaluate the ability of single source dual energy (SS-DECT) to decrease the artifacts related to placing one or both arms by the side of chest using monenergetic 75 Kev images and iterative reconstruction technique.

Our IRB approved study included 52 adult patients who underwent contrast enhanced chest CT. Twenty-six patients underwent chest DECT (13 patients (M:F 7:6, mean age 66± 17years,mean weight 81±21kg) with one arm or both by the side of chest; 13 patients (M:F 7:6,mean age 61±12years,mean weight 81±21kg) with both arms placed up) and 26 weight-matched patients who underwent contrast enhanced chest with single energy CT (SECT) (13 patients (M:F 8:5,mean age 57± 22years,mean weight 81±11kg) with one arm or both by side;13 patients (M:F 7:6,mean age 68±16years,mean weight 82±13kg) with both arms placed up). All chest CT exams were performed on a single source 64-row multidetector CT (GE 750HD Discovery). Additional 75 kev images at adaptive statistical iterative reconstruction (ASIR 70% strength) were generated for 13 patients with one arm or both by their side. All image series were assessed qualitatively for image quality, level of enhancement, and artifacts. CT numbers and noise was measured in main pulmonary artery (MPA) for all series. CTDIvol and DLP were recorded as well.

Radiation dose for DECT chest (CTDI:8±0.6mGy,DLP: 288±32mGy.cm). The vascular enhancement in (Mono 75 Kev ASIR70%) was rated as optimal or better in all patients (100%) for MPA and its lobar branches and in 69% (9/13 patients) for segmental and sub-segmental branches compared to just 85% and 54% for 60 kev images and 69% and 8% for 100 kev images. There was significant reduction in image noise and artifacts at the level of the tracheal carina and diaphragm with 75 kev images compared to the 60 and 100 kev images. There was a significant improvement in diagnostic quality with 75 kev compared to 60 and 75 kev images as well as SECT.

Conventional monoenergetic (60 and 100 kev) DECT images and SECT are substantially impaired when scanning is performed with one or both arms by the side. Monoenergetic 75 Kev images with ASIR70% help increase the diagnostic quality, and decrease artifacts without compromising vascular enhancement.

Appropriate modification to DECT of the chest can improve image quality in patients who can not place their arms above the shoulders

Otrakji, A, Flores, E, Lo Gullo, R, Digumarthy, S, Shepard, J, Kalra, M, Gilman, M, Trouble-shooting of Artifacts Related to Placement of Arms by the Side of the Chest during Dual Energy CT.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14017633.html