Study on Preoperative CT Angiography Scanning and Reconstruction Plan for Anterolateral Thigh Perforator Flap

Objective: The anterolateral thigh (ALT) flap is a multifunctional diaphyseal flap used to reconstruct head and neck defects. The location, destination, and source of the perforator vessels are crucial for developing a reasonable surgical plan. The small FOV technique can narrow the reconstruction field, increase image resolution, and enhance the spatial resolution of perforator vessels. The two-stage contrast injection method enhances peripheral vessel filling pressure. Multiplanar reformation (MPR) allows coronal reconstruction of the area of interest permitting observation of the distribution of the distal perforator vessels of the lateral circumflex femoral artery. Curved multiplanar reformation (CPR) generates a curved image of the perforator vessels by integrating the curved path of the perforator vessels with the volume-rendering image of the lateral circumflex femoral artery to determine the location and course of the perforator vessels. This study was performed to improve perforator flap vessel visualization using various computed tomography angiography (CTA) scanning and post-processing techniques. Methods: The study group consisted of 13 patients with head and neck tumor defects who underwent improved preoperative CTA scanning between January 2018 and August 2021 at our hospital’s Department of Otorhinolaryngology, Head and Neck Surgery. The control group included 13 patients with no significant lesions in the femoral artery or its branches who underwent non-spectral CT angiography of the bilateral lower extremity arteries between September 2020 and April 2023 at the Radiology Department of Beijing Friendship Hospital, Capital Medical University. Vascular imaging quality was subjectively scored, and the contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) of the lateral circumflex femoral artery were objectively evaluated. Results: While SNR in the intervention group was slightly higher than that in the control group, no significant difference was observed between the two groups. The average CNR in the study group was 18.25±7.38, while that in the control group was 7.26±2.64. The CNR in the study group was significantly higher than that in the control group, with a statistically significant difference between the two groups. No significant difference in subjective image quality scores was observed between the study and control groups. All perforator vessels detected on preoperative CTA in the study group were confirmed intraoperatively. Conclusions: Comprehensive application of multiple techniques increased the contrast between the perforator vessels and surrounding tissues, resulting in satisfactory CT image quality. These methods improve the accuracy of image analysis and provide better technical support for clinicians in analyzing the location, course, and source of blood vessels.