**5. Discussion**

The DIEP flap has numerous benefits in breast restoration, including big tissue acquisition, tissue similarity in the donor region, full preservation of rectus abdominis and anterior sheath tissue, and so on. It can also help with abdominal wall reconstruction in individuals who have abdominal fat accumulation. DIEP is currently the favored flap for autologous tissue breast surgery. However, due to its technological complexity, lengthy operation time, convoluted intraoperative links, and high postoperative complications, the operation of the DIEP flap is limited to some degree [8].

**Figure 6.** *A panoramic view of DIEP flap and immediate postoperative images.*

The choosing of flap perforator vessels and non-invasive anatomy are critical in DIEP surgery. There were, however, substantial variations in the starting position, diameter, and intramuscular course of flap perforator vessels between people or between lateral perforator vessels of the same individual. In traditional surgery, the main perforator is determined by a thorough assessment of each perforator during intraoperative anatomical investigation. The procedure is time-consuming, inefficient, and needs the physician to have extensive personal experience. Furthermore, perforator vessels have a smaller diameter, a wide range of form and location variability, which adds to the complexity and danger of operation [9].

During the development of DIEP flap for more than 30 years, a variety of methods and means for detecting and locating perforator vessels of flap have appeared in clinic. The commonly used methods include: portable ultrasonic Doppler examination: it was first used in 1975 to locate vascular perforator in flap surgery. Its advantages of simple operation, convenient portability and low cost can be used for preliminary vascular evaluation before surgery. However, studies have shown that its high false positive rate reduces the actual clinical guidance value [10]. Color Doppler examination: compared with portable ultrasonic Doppler, color Doppler can provide more detailed hemodynamic information, such as the origin, caliber, intramuscular shape, peak flow rate, resistance index, etc., so as to judge the vascular quality [11]. At present, it has been reported in the literature that color Doppler can detect perforator vessels with a diameter of about 0.7 mm, with an accuracy comparable to that of CTA. If combined with contrast-enhanced ultrasound examination, the effect of vascular development can be further improved [12]. High-resolution magnetic resonance angiography (MRA) examination, conventional MRA resolution is low, although with the emergence of high-resolution MRI and corresponding sequences, MRA can display perforator vessels with a diameter of 1 mm, and can even partially replace CTA examination, but its economy, practicability and scanning time are worth considering [13]. CTA examination: In 2006, Masia et al. [14] first used CTA to locate the inferior abdominal perforator vessel before surgery and selected the dominant perforator for breast reconstruction, and the imaging consistency rate of CTA reached 100%. CTA can provide accurate anatomical information on the perforating point, number, caliber and course of the perforating vessel of DIEP flap. Compared with other examinations, CTA is not susceptible to the influence of the patient's body type, vascular variation and deformity.

#### *Application of CT Angiography in Delayed DIEP Flap Breast Reconstruction DOI: http://dx.doi.org/10.5772/intechopen.112913*

At present, CTA imaging technology is more and more widely used in the field of flap repair abroad, especially in the application of abdominal DIEP flap for breast reconstruction after breast cancer surgery [15–17]. However, there are few domestic reports on the clinical application of CTA in delayed breast reconstruction after breast cancer surgery. In traditional DIEP breast reconstruction surgery, the perforator is usually evaluated by color Doppler. However, the accuracy of perforator localization is affected by false positive ultrasonography and operator's subjectivity to some extent. With the wide application of imaging technology, CTA can clearly display the anatomical information of perforator vessels with a diameter > 0.3 mm before surgery. As a "rehearsal" before surgery, surgeons can accurately conduct preoperative clinical operation simulation according to the picture [7]. In recent years, our center has conducted preoperative imaging evaluation for patients who plan to undergo delayed DIEP breast reconstruction. Combined with the different imaging evaluation methods in our hospital before and after 2018, this paper attempts to analyze the application value of CTA in delayed DIEP breast reconstruction surgery.

As a non-invasive, rapid, high image resolution, high accuracy and high specificity preoperative perforator vessel imaging method, CTA examination has been widely used in preoperative localization of perforator vessels of DIEP flap [15, 18]. In this study, we compared baseline data, intraoperative observed indicators, and incidence of postoperative complications between the CTA group and the US group. Among them, the CTA group was significantly better than the preoperative ultrasound localization group in choosing the time of perforator and the anatomic time of perforator. The time required to obtain the same mass flap was significantly shorter in CTA group than in ultrasound group (*p* < 0.001). This conclusion is consistent with most foreign studies [5, 6, 15]. All CTA data in this experiment were identified and read DICOM files by the surgeon himself through HOROS software in the mobile phone or computer. It can objectively evaluate and locate the number of perforator vessels before surgery, and perform a good preoperative operation simulation. At the same time, it is convenient for preoperative communication between doctors and patients, and can also play a positive role in promoting scientific research and teaching. On the other hand, CTA examination can get rid of the dependence of clinical surgeons on radiologists to a certain extent. Previous studies have shown that the agreement between surgeons and radiologists is 67.3%, and surgeons have higher accuracy of preoperative perforator localization [3, 17, 19].

In all cases of CTA, the surgeon can read, measure, draw and mark the intended surgical treatment cases anytime and anywhere in advance, regardless of the limitation of time and space, which is especially convenient for the formulation of remote consultation surgery plans for clinicians. In the CTA group, the operation time and cost can be saved when the skin flap is obtained. According to the study of Haddock et al. [3], compared with the group without preoperative CTA, the time to obtain the flap and the total operation time were longer. However, in the comparison of total operation time in this study, there was no significant statistical difference between the CTA group and the US group. Analysis of this reason may be due to: First, this study was bounded by time nodes. From January 2016 to January 2018, the perforator vessel was evaluated by ultrasonic localization, and from January 2018 to January 2021, the perforator vessel was evaluated by CTA. In the early stage (US group), the operator team paid more attention to the flap resection process. With the further improvement of surgical skills and surgical instruments, surgeons spent more energy on the flap shaping process in the later period (CTA group), which reduced the difference of total operation time between the two groups to a certain extent. Second, 92 cases were included in the US group and 206 in the CTA group in this study. The mismatch in the

number of cases may bias the experimental results to a certain extent. In addition, the results of this study indicated that, in the comparison of total operating time between the CTA group and the US group, the mean net operating time of the CTA group was shortened by 34 min. Although it did not translate into statistical *P* value difference, different results may occur with the matching or increasing of the number of cases. Third, in this study, the CTA group contained more patients with double pedicle reconstruction than the US group (58.7 vs. 56.5%), which increased the operation time to a certain extent. In addition, the preoperative evaluation of color Doppler ultrasound in the control group has a certain guiding value for the localization of perforator branches.

The presence of scar in previous abdominal surgery may affect the effect of DIEP flap reconstruction, because scar tissue may affect the normal distribution of blood supply in the abdominal flap, and in severe cases affect the normal shape of perforator vessels, thus increasing the difficulty of surgical anatomy [20, 21]. However, preoperative CTA examination can clearly show the integrity and shape of the deep vessels and perforator vessels under the abdominal wall, which is of greater reference value for patients with surgical history. The present study was stratified according to whether there was a history of accompanying abdominal surgery. The results showed that: for patients with a history of abdominal surgery, the time of flap resection and total operation time in CTA group were lower than those in US group (*P* < 0.05). For patients with no history of abdominal surgery, the time of flap resection in CTA group was lower than that in US group (*P* < 0.05), and there was no significant difference in total operation time (*P* > 0.05). Therefore, it is of great significance to strengthen preoperative CTA examination for patients with a history of abdominal surgery.

In the comparison of postoperative complications between the two groups, 92 patients in the US group had complete necrosis of the skin flap, and 206 patients in the CTA group had all survived. Although the difference between the two groups was not statistically significant, the CTA group may have a higher flap survival rate. To this end, we again compared the rate of secondary surgical exploration between the two groups, the US group was 13.04% (12/92) and the CTA group was 2.91% (6/206), the difference was statistically significant (*P* < 0.001), and CTA could reduce the risk of secondary surgical exploration to a certain extent. As for the consistency comparison between the intraoperative perforator and the dominant perforator evaluated based on imaging data, the consistency rate of imaging surgery was 97.09% (200/206) in the CTA group and 43.48% (40/92) in the US group, the difference was statistically significant (*P* < 0.001). Therefore, CTA examination can more accurately select, measure and locate the dominant perforator before surgery.

CTA examination is not only limited to the application of perforating branches of abdominal flaps, but also can further evaluate the conditions of blood vessels in the chest receiving area (internal arteriovenous) during the preoperative thoracoabdominal joint examination. Especially for some patients with radiation ulcers, reasonable selection of blood vessels in the receiving area can further increase the probability of successful surgery [22]. In addition, in some patients with a history of abdominal surgery, CTA can be better used to evaluate the conditions of abdominal perforator vessels, so as to guide the selection of surgical methods. However, as with any form of imaging, preoperative CTAs are inevitably subject to unexpected findings. Literature reported that the incidence of accidental discovery was 13–75% in CTA studies on DIEP flap program [16]. Wagner et al. suggested that among the 350 patients who met the criteria, 56.9% of the patients found lung nodules and abdominal diseases without special intervention in preoperative imaging examination, 12.9% of the patients

*Application of CT Angiography in Delayed DIEP Flap Breast Reconstruction DOI: http://dx.doi.org/10.5772/intechopen.112913*

received additional imaging examination, and 4.0% of the patients received additional intervention, such as puncture biopsy of lung tumors. In addition, abdominal CTA examination is conducive to the selection of donor skin flap during breast reconstruction surgery, and preoperative CTA evaluation is especially important for patients who plan to undergo SIEA skin flap operation [23, 24]. However, CTAs also have some disadvantages: patients need to be exposed to radiation, which may trigger a certain risk of cancer; In addition, the use of iodine contrast media may cause a small number of people allergic reactions, kidney damage and other unpredictable unexpected conditions.

In summary, CTA technology can accurately provide detailed anatomical information of perforator vessels, facilitate surgical design, reduce intraoperative perforator selection and dissection time, reduce the risk of secondary surgical exploration, and have a high imaging and surgical consistency rate, especially for patients with a history of abdominal surgery, CTA is of higher value. Therefore, CTA examination is worthy of clinical application in delayed DIEP breast flap reconstruction.

## **6. Conclusions**

In delayed DIEP flap breast reconstruction, CTA can significantly shorten the choice time of flap perforation and anatomy time, reduce the risk of secondary surgical exploration and has a high rate of image surgery consistency, which can effectively guide the operation.

## **Acknowledgements**

Xu yuanbing: thesis design, writing, modification, and data proofreading, Pan dai: imagine data measurement and statistics, paper revision, Xu hua: thesis design and revision. The author(s) read and approved the final manuscript. This work was supported by funding from a special fund in the field of major health of the Science and Technology Department of Hubei Province (2022BCE041) and the Natural Science Foundation of Xiaogan City (XGKJ2022010006).

#### **Conflict of interest**

The copyright of this academic study belongs to the "Chinese Journal of Cancer." We thank the editor and reviewers of the Journal for their guidance and assistance in the Chinese submission. The English version is the translation of the Chinese version. Please point out if there are any improper points.

#### **Acronyms and abbreviations**


*Breast Reconstruction – Conceptual Evolution*
