Optimization of Computed Tomography Angiography Protocols for Follow-Up Type B Aortic Dissection Patients by Using 3D Printed Model

Abstract

Thoracic endovascular aortic repair (TEVAR) is a life-saving therapy for type B aortic dissection (TBAD). However, surveillance computed tomography (CT) scans in post-TEVAR patients are associated with high radiation dose, thus resulting in potential risk of radiation-induced malignancy. In this study, we developed a patient-specific three-dimensional (3D) printed phantom with stent grafts in situ, then scanned the phantom with different CT protocols to determine the optimal scanning parameters for post-treatment patients. The CT scans were conducted with different kVp and pitch values (80, 100, 120 kVp and pitch of 1.2, 1.5, 2.0, 2.5), resulting in a total of 12 datasets. Signal-to-noise ratio (SNR) was measured to determine and compare the image quality between different datasets. Results showed no significant differences in SNR between different kVp when the pitch value was 1.2. At low pitch values, a decrease in kVp from 120 to 80 led to a significant effective dose reduction by more than 20%. SNR decreased by 30% when pitch was increased from 1.2 to 2.5 at 80 kVp, and 20% at 120 kVp. In contrast, there was only a 3.9% decrease in SNR when kVp was reduced from 120 to 80 at pitch 1.2, and 15.9% at pitch 2.5. High pitch with 100 kVp can effectively reduce the dose while maintaining image quality.

3D Printed Models in Cardiovascular Disease: An Exciting Future to Deliver Personalized Medicine

“…In previous studies, TangoPlus FLX930, TangoGray TM and TangoBlack TM (Stratasys) are reported to produce 3D printed heart and vascular models with soft and elastic features [ 24 ]. Recent research has shown that Visijet CE-NT (3D Systems Inc., Wilsonville, OR, USA) has the same tissue properties as cardiac tissues with similar CT attenuation; thus, it is more suitable for the 3D printed heart and vascular models ( Figure 3 ) [ 25 ].…”

“…Printing materials have an impact on the user’s performance when performing a simulation of interventional procedures as 3D models printed with soft and elastic materials allow the user to acquire a similar tactile experience to human vascular tissue, and this is especially important for structures like vessels and cardiac valves as highlighted in some studies [ 64 , 65 ]. Current developments in 3D printing technologies and printing materials have enabled achieving this goal with the selection of appropriate materials to replicate human cardiovascular tissue properties [ 25 , 70 ]. Evidence strongly recommends that 3D printed vascular models serve as a valuable tool for simulating and rehearsing cardiac or interventional radiology procedures.…”

“…Further, 3D printed models of type B aortic dissection were developed using CT datasets to replicate true lumen, false lumen, aortic aneurysm, and insertion of the aortic stent graft to simulate EVAR ( Figure 3 ) [ 25 ]. CT scans were conducted to investigate the optimal aortic CT angiography (CTA) protocols in the follow-up of patients with aortic dissection following EVAR treatment.…”

“…CT scans were conducted to investigate the optimal aortic CT angiography (CTA) protocols in the follow-up of patients with aortic dissection following EVAR treatment. Low kilovoltage peak (80 kVp) and high pitch (2.0) can be suggested as the optimal CT protocol with a reduction of more than 20% radiation dose without affecting image quality as assessed quantitatively and qualitatively ( Figure 14 ) [ 25 , 88 ]. Since aorta CTA is the preferred imaging modality for both diagnosis of aortic aneurysm/dissection and follow-up of EVAR patients due to consecutive CT scans at regular periods, low-dose CT protocol is of paramount importance to minimize radiation dose.…”

“…Third, the use of appropriate printing materials plays an important role, especially in the simulation of cardiac or interventional procedures, such as the operators need to experience a similar feeling when performing the simulation on 3D printed models so that clinicians and students can gain confidence and skills that are required to operate on real patients. This is already achievable with the current printing materials [ 25 , 63 , 70 , 88 ].…”