High-pitch, low-voltage and low-iodine-concentration CT angiography of aorta: assessment of image quality and radiation dose with iterative reconstruction.

Yanguang Shen,Nan Zhang,Lei Xu,Zixu Yan,Yu Li,Zhonghua Sun,Zhanming Fan,Heye Zhang

doi:10.1371/journal.pone.0117469

Yanguang Shen, Nan Zhang + Show 6 more

Open Access

https://doi.org/10.1371/journal.pone.0117469

Copy DOI

Abstract

ObjectiveTo assess the image quality of aorta obtained by dual-source computed tomography angiography (DSCTA), performed with high pitch, low tube voltage, and low iodine concentration contrast medium (CM) with images reconstructed using iterative reconstruction (IR).MethodsOne hundred patients randomly allocated to receive one of two types of CM underwent DSCTA with the electrocardiogram-triggered Flash protocol. In the low-iodine group, 50 patients received CM containing 270 mg I/mL and were scanned at low tube voltage (100 kVp). In the high-iodine CM group, 50 patients received CM containing 370 mg I/mL and were scanned at the tube voltage (120 kVp). The filtered back projection (FBP) algorithm was used for reconstruction in both groups. In addition, the IR algorithm was used in the low-iodine group. Image quality of the aorta was analyzed subjectively by a 3-point grading scale and objectively by measuring the CT attenuation in terms of the signal- and contrast-to-noise ratios (SNR and CNR, respectively). Radiation and CM doses were compared.ResultsThe CT attenuation, subjective image quality assessment, SNR, and CNR of various aortic regions of interest did not differ significantly between two groups. In the low-iodine group, images reconstructed by FBP and IR demonstrated significant differences in image noise, SNR, and CNR (p<0.05). The low-iodine group resulted in 34.3% less radiation (4.4 ± 0.5 mSv) than the high-iodine group (6.7 ± 0.6 mSv), and 27.3% less iodine weight (20.36 ± 2.65 g) than the high-iodine group (28 ± 1.98 g). Observers exhibited excellent agreement on the aortic image quality scores (κ = 0.904).ConclusionsCT images of aorta could be obtained within 2 s by using a DSCT Flash protocol with low tube voltage, IR, and low-iodine-concentration CM. Appropriate contrast enhancement was achieved while maintaining good image quality and decreasing the radiation and iodine doses.

Highlights

Multislice computed tomography angiography (CTA) has become the preferred method to assess aortic diseases [1,2,3,4,5,6]
In the low-iodine group, images reconstructed by filtered back projection (FBP) and iterative reconstruction (IR) demonstrated significant differences in image noise, SNR, and CNR (p
The low-iodine group resulted in 34.3% less radiation (4.4 ± 0.5 mSv) than the high-iodine group (6.7 ± 0.6 mSv), and 27.3% less iodine weight (20.36 ± 2.65 g) than the high-iodine group (28 ± 1.98 g)

Summary

Introduction

Multislice computed tomography angiography (CTA) has become the preferred method to assess aortic diseases [1,2,3,4,5,6]. X-ray radiation and iodine hazards are the major concern associated with CTA, as repeat CTA scans are commonly performed during pre- and postoperative assessments of aortic disease [7,8,9]. To address these concerns, clinical studies have recently reported the use of the second-generation dual-source computed tomography (DSCT) Flash protocol for dose reduction. Clinical studies have recently reported the use of the second-generation dual-source computed tomography (DSCT) Flash protocol for dose reduction This protocol uses a high-pitch acquisition mode, reducing the scan time for the entire aorta to about 2 s and with resultant very low radiation dose [10,11]. That study used a CM with a high concentration of iodine (370 mg I/mL)

Methods

Results

Conclusion