Michael Marcus Lell MD, Presenter: Nothing to Disclose

Matthias Stefan May, Abstract Co-Author: Nothing to Disclose

Paul Deak DIPLPHYS, PhD, Abstract Co-Author: Employee; General Electric Company

Willi A. Kalender PhD, Abstract Co-Author: Consultant, Siemens AG Consultant, Bayer AG Founder, CT Imaging GmbH Scientific Advisor, CT Imaging GmbH Shareholder, CT Imaging GmbH Founder, Artemis Imaging GmbH CEO, Artemis Imaging GmbH Shareholder, Artemis Imaging GmbH

Stephan Achenbach MD, Abstract Co-Author: Speakers Bureau, Siemens AG Consultant, SERVIER Research grant, Siemens AG Research grant, Bayer AG

Michael Uder MD, Abstract Co-Author: Speakers Bureau, Bracco Group Speakers Bureau, Bayer AG Research Consultant, Insight Agents GmbH Research Consultant, General Electric Company Research grant, Siemens AG Research grant, Koninklijke Philips Electronics NV

Computed tomography (CT) is considered the method of choice in thoracic imaging for a variety of indications in children, but sedation is oftennecessary to avoid severe motion artifacts. We evaluated a new, sub-second high-pitch scan mode, that obviates the need of sedation and to hold the breath.

54 patients were included in this study. 23 patients (mean age 22±21 month, range 0 – 56 month) were examined with a dual source CT system in a high-pitch (p=3.0) scan mode. Scan parameters were as follows: pitch = 3.0, 128 x 0.6 mm slice acquisition, 0.28 s gantry rotation time, ref.mAs adapted to the body weight at 80kV. Images were reconstructed with a slice thickness of 0.75 mm. None of the children was sedated for the CT examination and no breathing instructions were given. Image quality was assessed focusing on motion artifacts and delineation of the vascular structures and lung parenchyma. 31 patients (mean age 16±18 month, range 0 – 55 month) were examined under sedation on 2 different CT systems (10-slice CT, n= 18; 64-slice CT, n= 13 patients) in conventional spiral mode. Dose values were calculated from the dose length product (DLP) provided in the patient protocol/dose report, Monte Carlo simulations were performed to assess dose distribution for a conventional and high-pitch scan mode.

All scans were performed without complications. Image quality was superior with the high-pitch scan mode, due to a significant reduction of motion artifacts. In the control group artifacts were encountered at the level of the diaphragm (n=31; 100%), the borders of the heart (n=31; 100%), and the ribs (n=20; 65%) and spine (n=6; 19%), while motion artifacts were detected in the high-pitch group only in two patients in the lung parenchyma next to the diaphragm or the heart. Dose values were within the same range (dose reduction ~5% with the high-pitch mode), although z-overscanning increased with the increase of detector width and pitch-value.

High-pitch chest CT is a robust method to provide highest image quality making sedation or controlled ventilation for the examination of infants, small or uncooperative children unnecessary, while maintaining low radiation dose values.

Sedation is not necessary any more for the evaluation of thoracic pathologies in pediatrics. This reduces procedural time and costs.

Lell, M, May, M, Deak, P, Kalender, W, Achenbach, S, Uder, M, High Pitch Spiral CT in Pediatric Cardiovascular Imaging: Image Quality and Radiation Dose.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9013775.html