**2. Research method**

#### **2.1 Grouping overview**

This study has collected clinical data from 298 female patients undergoing breast reconstruction surgery following breast cancer surgery, ranging in age from 25 to 67 years (mean age 42.2 ± 8.28 years). Before undergoing reconstructive surgery, all patients had conventional tumor therapy and were in a stable disease phase. In January 2016 and January 2018, 92 patients (US group) had their data gathered. Prior to surgery, these patients were subjected to a color Doppler ultrasound examination to examine abdominal vascular perforators using a GE Logiq 700 ultrasonography machine with a probe frequency of 10–13 MHz and a color Doppler frequency of 7.5 MHz, with a maximum velocity of 2 cm/s. The focus of the examination was to accurately detect where the target perforator vessels exited the deep fascia and entered the subcutaneous fat layer, and then to label the matching surface projection. As the observation group, data from 206 patients was gathered between January 2018 and January 2021 (CTA group). These patients underwent abdominal vascular perforator evaluation prior to surgery using a Philips Brilliance 256i CT scanner, which used a non-ionic iodine contrast agent (iopromide) with a volume of 90–100 mL and an injection rate of 4 mL/s, introduced via a vein on the back of the hand or at the elbow. The following CTA settings were employed with a single high-pressure injector: 120 kVp, 250 mA, detector 128 × 0.625 mm, pitch 0.977, 512 × 512 matrix, and a 350 mm field of view.

#### **2.2 CTA image data processing**

The HOROS software was used to evaluate the data and establish the location and trajectory of perforator vessels, which were then marked on the patient's body surface.

#### **2.3 Research indexs**

Baseline data were collected for both groups and compared, including age, body mass index (BMI), history of hypertension or diabetes, history of tumor chemotherapy, chest wall radiation history, abdominal surgery history, smoking history, and single/double pedicle flap blood supply. In addition, intraoperative and postoperative evaluation indices were statistically analyzed. Intraoperative evaluation indices included the number of perforators located preoperatively, the number of perforators utilized during the surgery, the decision-making time for perforators, perforator dissection time, flap harvesting time, flap total weight, and total operation time. The postoperative evaluation indices included abdominal incision infection rate, fat necrosis rate, re-exploration rate, and complete flap necrosis rate.
