Clinical Feasibility of a Low-dose Computed Tomography Angiography Protocol with an Iterative Reconstruction Algorithm in Preoperative Examinations for Anterolateral Thigh Perforator Flap Surgery

Background: In the past several years, emerging imaging techniques, such as computed tomography angiography (CTA), Doppler ultrasound, and magnetic resonance imaging (MRI), have been used for investigating the anatomy and perfusion of perforator complexes. Preoperative CTA can provide explicit information on perforator flaps, which not only helps surgeons to evaluate the optimal design of flaps with respect to the lateral circumflex femoral artery (LCFA) territory and the concomitant venous drainage pattern, but also reduces postoperative complications and secondary operation rates. Objectives: This study aimed to evaluate the clinical feasibility of a low-dose CTA protocol with adaptive statistical iterative reconstruction (ASIR) for patients scheduled for anterolateral thigh perforator flap (ALTPF) surgery. Patients and Methods: This prospective randomized controlled trial was conducted in a single institution from August 2016 to July 2017. A total of 60 inpatients scheduled for the ALTPF surgery were randomly allocated into three groups (n = 20 per group): Group A, filtered back projection (FBP) reconstruction with a tube voltage of 120 kVp; group B, ASIR with a tube voltage of 100 kVp; and group C, ASIR with a tube voltage of 80 kVp. The vessel attenuation value, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) were compared between the three groups. Additionally, a four-point Likert scale was used to evaluate the subjective quality of images. The scan length, dose-length product (DLP), CT dose index (CTDI), and effective dose (ED) were also recorded and compared. Results: The age, sex, and body mass index (BMI) were not significantly different between the three groups (P > 0.05 for all). The FOM of images in the three segments was significantly higher in group C compared to the other two groups (P < 0.001 for all). The results of subjective evaluation revealed no poor-quality images, and the Likert score did not significantly differ between the groups. Compared to group A and group B, significant reductions were observed in CTDI, DLP, and ED in group C. Conclusion: The 80-kVp protocol with ASIR not only reduced the radiation dose, but also exhibited lower performance compared to the 120-kVp protocol with FBP and the 80-kVp protocol with ASIR; it also yielded relatively satisfactory image quality.