Investigation of Three-dimensional Printing Materials for Printing Aorta Model Replicating Type B Aortic Dissection
Authors: Wu Chia-An , Squelch Andrew , Sun Zhonghua 
Published: February 2021

Aim:
This study aims to determine a printing material that has both elastic property and
radiology equivalence close to the real aorta for simulation of endovascular stent-graft repair of aortic
dissection.

Background:
With the rapid development of Three-Dimensional (3D) printing technology, a patient-
specific 3D printed model is able to help surgeons to make a better treatment plan for Type B
aortic dissection patients. However, the radiological properties of most 3D printing materials have
not been well characterized. This study aims to investigate the appropriate materials for printing human
aorta with mechanical and radiological properties similar to the real aortic Computed Tomography
(CT) attenuation.

Objective:
Quantitative assessment of CT attenuation of different materials used in 3D printed models
of aortic dissection for developing patient-specific 3D printed aorta models to simulate type B
aortic dissection.

Methods:
A 25-mm length of aorta model was segmented from a patient’s image dataset with a diagnosis
of type B aortic dissection. Four different elastic commercial 3D printing materials, namely
Agilus A40 and A50, Visijet CE-NT A30 and A70 were selected and printed with different hardness.
Totally four models were printed out and CT scanned twice on a 192-slice CT scanner using
the standard aortic CT angiography protocol, with and without contrast inside the lumen. Five reference
points with the Region Of Interest (ROI) of 1.77 mm2 were selected at the aortic wall, and intimal
flap and their Hounsfield units (HU) were measured and compared with the CT attenuation of
original CT images. The comparison between the patient’s aorta and models was performed
through a paired-sample t-test to determine if there is any significant difference.

Result:
The mean CT attenuation of the aortic wall of the original CT images was 80.7 HU. Analysis
of images without using contrast medium showed that the material of Agilus A50 produced the
mean CT attenuation of 82.6 HU, which is similar to that of original CT images. The CT attenuation
measured at images acquired with the other three materials was significantly lower than that of
the original images (p<0.05). After adding contrast medium, Visijet CE-NT A30 had an average
CT attenuation of 90.6 HU, which is close to that of the original images without a statistically significant
difference (p>0.05). In contrast, the CT attenuation measured at images acquired with other
three materials (Agilus A40, A50 and Visiject CE-NT A70) was 129 HU, 135 HU and 129.6 HU,
respectively, which is significantly higher than that of original CT images (p<0.05).

Conclusion:
Both Visijet CE-NT and Agilus have tensile strength and elongation close to actual patient’s
tissue properties producing similar CT attenuation. Visijet CE-NT A30 is considered the appropriate
material for printing aorta to simulate contrast-enhanced CT imaging of type B aortic dissection.
Due to the lack of body phantoms in the experiments, further research with the simulation
of realistic anatomical body environment should be conducted.