Iterative reconstruction improves image quality and reduces radiation dose in trauma protocols; A human cadaver study.

Johannes Clemens Godt,Anselm Schulz,Cathrine K Johansen,Arne Stray-Pedersen,Anne Catrine T Martinsen,Kristin Jensen,Johann Baptist Dormagen,Helga M Brøgger

doi:10.1177/20584601211055389

Johannes Clemens Godt, Anselm Schulz + Show 6 more

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https://doi.org/10.1177/20584601211055389

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Abstract

BackgroundRadiation-related cancer risk is an object of concern in CT of trauma patients, as these represent a young population. Different radiation reducing methods, including iterative reconstruction (IR), and spilt bolus techniques have been introduced in the recent years in different large scale trauma centers.PurposeTo compare image quality in human cadaver exposed to thoracoabdominal computed tomography using IR and standard filtered back-projection (FBP) at different dose levels.Material and methodsTen cadavers were scanned at full dose and a dose reduction in CTDIvol of 5 mGy (low dose 1) and 7.5 mGy (low dose 2) on a Siemens Definition Flash 128-slice computed tomography scanner. Low dose images were reconstructed with FBP and Sinogram affirmed iterative reconstruction (SAFIRE) level 2 and 4. Quantitative image quality was analyzed by comparison of contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Qualitative image quality was evaluated by use of visual grading regression (VGR) by four radiologists.ResultsReaders preferred SAFIRE reconstructed images over FBP at a dose reduction of 40% (low dose 1) and 56% (low dose 2), with significant difference in overall impression of image quality. CNR and SNR showed significant improvement for images reconstructed with SAFIRE 2 and 4 compared to FBP at both low dose levels.ConclusionsIterative image reconstruction, SAFIRE 2 and 4, resulted in equal or improved image quality at a dose reduction of up to 56% compared to full dose FBP and may be used a strong radiation reduction tool in the young trauma population.

Highlights

Computed tomography is one of the most important diagnostic medical tools nowadays.[1]
contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) showed significant improvement for images reconstructed with Sinogram affirmed iterative reconstruction (SAFIRE) 2 and 4 compared to filtered back-projection (FBP) at both low dose levels
Iterative image reconstruction, SAFIRE 2 and 4, resulted in equal or improved image quality at a dose reduction of up to 56% compared to full dose FBP and may be used a strong radiation reduction tool in the young trauma population

Summary

Introduction

Computed tomography is one of the most important diagnostic medical tools nowadays.[1]. Prompt diagnostic evaluation of their injuries.[5] At our institution, a single-pass split-bolus CT of thorax and abdomen is applied to the majority of trauma patients.[6] For this type of thoracoabdominal CT scan, data from our National Radiation and Nuclear Safety Authority report an average dose of 14.2 mSv.[7] In cases of pelvic or urinary tract injury, further arterial or delayed phase scans are obtained and increase radiation dose is administered to the patient.[8,9] Filtered back-projection has traditionally been the most widely used image reconstruction method, but dose reduction potential of this method is limited.[10,11] Iterative reconstruction techniques have been introduced, by all CT vendors, to reduce image noise compared to FBP.[12,13,14] Sinogram affirmed iterative reconstruction (SAFIRE®, Siemens Healthineers, Erlangen, Germany) is decreasing image noise and artefacts, and preserving edges, in a statically iterative process with five different levels of IR levels available where SAFIRE 1 is the mildest and SAFIRE 5 the strongest.[13,15]. Different radiation reducing methods, including iterative reconstruction (IR), and spilt bolus techniques have been introduced in the recent years in different large scale trauma centers.

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