Radiation dose reduction using iterative reconstruction for aortic valve and thoracic aortic calcification measurements

Congress:

ESCR 2016

Poster Number:

P-0022

Type:

Scientific Poster

Keywords:

Calcifications / Calculi, Radiation safety, Image manipulation / Reconstruction, CT, Radioprotection / Radiation dose, Computer applications, Arteries / Aorta

Authors:

R. W. van Hamersvelt¹, A. M. den Harder¹, M. J. Willemink¹, A. Schilham¹, J. W. J. Lammers¹, H. Nathoe¹, R. P. J. Budde², T. Leiner¹, P. A. de Jong¹; ¹Utrecht/NL, ²Rotterdam/NL

DOI:

DOI-Link:

https://dx.doi.org/

Fig. 1: Dose reduction and iterative reconstruction. Chest CT acquisitions of one...

Fig. 4: Influence of dose reduction and iterative reconstruction, example of...

Fig. 2: Diagnostic value for cardiac CT. Number of false positive (FP) and false...

Fig. 3: Diagnostic value for chest CT. Number of false positive (FP) and false negative...

Purpose

Cardiac and chest computed tomography (CT) are commonly performed for a wide range of indications. However, radiation dose is an important topic and radiation dose reduction is therefore widely investigated. With the use of iterative reconstruction (IR), image noise is reduced and thereby allows dose reduction without loss of image quality [1]. Several studies suggest that radiation dose can be substanially reduced when using IR [1-4], however it is unknown if dose reduction and/or iterative reconstruction have an effect on thoracic aortic calcification (TAC) and...

Methods and Materials

Twenty patients underwent chest CT and 28 patients electrocardiogram-triggered cardiac CT on a 256-slice CT scanner without using contrast. Each patient was scanned four times (routine dose and approximately 45, 60 and 75% reduced dose), dose reduction was achieved by reducing mAs. Images were reconstructed using filtered back projection (FBP), three hybrid (iDose4) levels and three model-based IR (IMR) levels (Fig. 1). iDose4levels 1, 4 and 7 were used for cardiac CT and levels 1, 4 and 6 for chest CT. IMR levels 1, 2...

Results

In total 48 patients (31 males; 60±8.8 years; BMI 28.4±5.1 kg/m2) were included. The amount of dose per protocol is depicted in table 1. AVC was present in 14 (29%) and TAC in 17 (57%) patients. The amount of false postive and negative and number of diagnostic scans (subjective score ≥2) are shown in Fig. 2for cardiacand Fig. 3 forchest CT.Median mass scores for AVC and TAC at the reference scan were 12.0(1.4-24.0) and 2.7(1.1-15.8) at cardiac CT and 17.0(4.9-50.2) and 455.6(132.6-1796.9) at chest CT....

Conclusion

AVC and TAC quantification on CT is possible at sub-milliSievert dose using IR.

References

1. Willemink MJ, Leiner T, de Jong PA, de Heer LM, Nievelstein RA, Schilham AM, Budde RP. Iterative reconstruction techniques for computed tomography part 2: initial results in dose reduction and image quality. Eur Radiol. 2013 Jun;23(6):1632-42. 2.Hu XH, Ding XF, Wu RZ, Zhang MM. Radiation dose of non-enhanced chest CT can be reduced 40% by using iterative reconstruction in image space. Clin Radiol. 2011 Nov;66(11):1023-9. 3.Katsura M, Matsuda I, Akahane M, Sato J, Akai H, Yasaka K, Kunimatsu A, Ohtomo K. Model-based iterative reconstruction...