Patient-specific 3D printed pulmonary artery model with simulation of peripheral pulmonary embolism for developing optimal computed tomography pulmonary angiography protocols

Abstract

Background: Computed tomography pulmonary angiography (CTPA) is the preferred imaging modality for diagnosis of patients with suspected pulmonary embolism (PE). Radiation dose associated with CTPA has been significantly reduced due to the use of dose-reduction strategies, however, investigation of low-dose CTPA with use of different kVp and pitch values has not been systematically studied. The aim of this study was to utilize a 3D printed pulmonary model with simulation of small thrombus in the pulmonary arteries for development of optimal CTPA protocols. Methods: Animal blood clots were inserted into the pulmonary arteries to simulate peripheral embolism based on a realistic 3D printed pulmonary artery model. The 3D printed model was scanned with 192-slice 3 rd generation dual-source CT with 1 mm slice thickness and 0.5 mm reconstruction interval. All images were reconstructed with advanced modelled iterative reconstruction (IR) at a strength level of 3. CTPA scanning parameters were as follows: 70, 80, 100 and 120 kVp, 0.9, 2.2 and 3.2 pitch values. Quantitative assessment of image quality was determined by measuring signal-to-noise ratio (SNR) in both main pulmonary arteries, while qualitative analysis of images was scored by two experienced radiologists (score of 1 indicates poor visualization of thrombus with no confidence, and score of 5 excellent visualization of thrombus with high confidence) to determine the image quality in relation to different scanning protocols for detection of thrombus in the pulmonary arteries. Results: No significant differences were found in SNR measurements among all CTPA protocols (P>0.05), regardless of kVp or pitch values used, although SNR was higher with 120 kVp and 0.9 and 2.2 pitch protocols than that in other protocols. The thrombi were detected in all images, with 70 kVp and 3.2 pitch protocol scored the lowest with a score of 3 by two observers, and images with other protocols were scored 4 or 5. Lowering kVp from 120 to 70 with use of high-pitch 2.2 or 3.2 protocol resulted in up to 80% dose reduction without significantly affecting image quality. Conclusions: Low-dose CT pulmonary angiography protocols comprising 70 kVp and high pitch 2.2 or 3.2 allow for detection of peripheral PE with significant reduction in radiation dose while images are still considered diagnostic.

3D printing in medicine: current applications and future directions

“…Patient-specific 3D-printed models based on patient's imaging data offer realistic models with a high accuracy in replicating anatomy and pathology, thus serving as a reliable tool to optimize CT protocols. Currently, 3D-printed heart and pulmonary artery models have been used to test different CT scanning protocols for dose optimization (47)(48)(49). The 3D-printed cardiac insert phantom developed by Abdullah et al represents a novel approach for optimizing cardiac CT protocols (48), while 3D-printed pulmonary artery model by Aldosari et al indicates another new approach for optimizing CT pulmonary angiography protocols with simulation of main and peripheral pulmonary embolism ( Figure 5).…”

“…The 3D-printed cardiac insert phantom developed by Abdullah et al represents a novel approach for optimizing cardiac CT protocols (48), while 3D-printed pulmonary artery model by Aldosari et al indicates another new approach for optimizing CT pulmonary angiography protocols with simulation of main and peripheral pulmonary embolism ( Figure 5). Significant dose reduction up to 80% can be achieved with resulting diagnostic images of detecting pulmonary embolism at the main and peripheral pulmonary arteries, thus highlighting the feasibility of using 3D-printed pulmonary model for developing low-dose CT protocols (48,49).…”

Insights into 3D printing in medical applications

“…Of 8 original articles, 4 focused on the usefulness of 3D printing in cardiovascular disease with 2 of them studying the optimal computed tomography pulmonary angiography (CTPA) protocols based on their developed 3D printed pulmonary artery model (15,16). Pulmonary embolism was simulated by inserting the animal blood clots in the main pulmonary arteries with CTPA scans performed on the 2 nd generation of dual-source CT scanners (15).…”

“…Dose reduction up to 80% was achieved when lowering kVp from 120 to 100 or 80 without significantly affecting image quality in detecting main pulmonary embolism, while use of 70 kVp and high pitch of 3.2 was not recommended due to suboptimal image quality when CT scans were done a 128-slice dualsource CT. However, in the subsequent experiments of simulating peripheral pulmonary embolism using the same approach, authors tested the same CTPA protocols on the latest 192-slice 3 rd generation dual-source CT scanner with images reconstructed using advanced modelled iterative reconstruction (ADMIRE) (16). Both qualitative and quantitative assessments of image quality showed that lowdose CTPA is achievable with use of 70 kVp and high pitch of 2.2 or 3.2, with significant dose reduction while still maintaining diagnostic images of detecting small emboli in the pulmonary arteries.…”

3D printed coronary models offer new opportunities for developing optimal coronary CT angiography protocols in imaging coronary stents

“…An increasing trend in research and publications have been observed recently in the journal of Quantitative Imaging in Medicine and Surgery (QIMS), especially in the 2019 January special issue with a focus on 3D printing in medicine. In that special issue, a number of publications (original studies, technical notes and review articles) were contributed by researchers from different countries with expertise in different fields highlighting the importance of 3D printing in medical applications (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). In addition to these applications, a recent paper in this issue of QIMS presents another new research direction of using personalized 3D printed coronary artery models for simulation of coronary stenting procedure (14).…”