Introduction:
An abdominal aortic aneurysm is defined as an enlarged area present below the main blood vessel (aorta), which supplies blood to the body. The aorta starts from the heart and passes through the chest and abdomen. The rupture of an abdominal aortic aneurysm can cause life-threatening bleeding because the aorta is the largest blood vessel in the body. Depending on the total size of the aneurysm and how fast it increases in size, treatment may range from waiting to emergency surgery.
What Is Endovascular Aneurysm Repair?
Endovascular aneurysm repair (EVAR) is an invasive procedure that can be used to treat abdominal aortic aneurysms. The aorta is the largest artery present in the body. It helps carry blood from the heart to the rest of the body. In the case of the presence of an abdominal aortic aneurysm, EVAR involves the use of small punctures and sophisticated instruments to repair the bulging vessel (aneurysm). The goal of EVAR is to prevent the rupture of abdominal aortic aneurysms. This condition is a life-threatening event. The force of blood flow against a weak spot in the vessel wall (here, the aorta) causes the aortic wall to bulge outwards, creating an aneurysm. This can rupture and block blood flow to the organ. Life-threatening complications can occur within minutes.
What Are the Benefits of Endovascular Aneurysm Repair?
Because EVAR is a minimally invasive procedure, it is gentle on the body. Benefits include:
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Fewer days of hospitalization.
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Less blood loss.
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Less discomfort during recovery.
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Faster return to daily life. The risk of heart attack and death during surgery is lower than with open surgery.
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Operative time is shorter than open surgery.
What Is Cone-Beam CT?
Cone-beam CT (CBCT), a variant of computed tomography (CT) used especially in dental and extremity imaging, has recently found new applications in dedicated breast imaging. Unlike conventional CT, it uses a cone-shaped X-ray beam and a two-dimensional detector instead of a fan-shaped X-ray beam and a one-dimensional detector. In cone-beam CT, a diverging, cone-shaped radiation source is aimed at a target. The attenuated X-rays are detected on the opposite side by an X-ray detector with several dexels on the x- and y-axes 2. Therefore, volume acquisition can be performed with a smaller number of rotations of the X-ray tube gantry. This differs from fan-beam CT, which uses a 2D fan X-ray beam with a helical gradient to acquire the image data. Furthermore, fan-beam CT detectors only have dexels on the x-axis. The advent of cone-beam CT has brought several advantages over fan-beam CT, but it also has inherent drawbacks.
Diagnosis and treatment planning accurately are the cornerstones of any medical treatment. For this reason, cone beam computed tomography (CBCT) was introduced and is widely used. CBCT technology provides a three-dimensional image display that allows precise localization and coverage of lesions or anatomical regions. CBCT can be of great use in the surgical field but also other fields, such as endodontics, prosthetics, and orthodontics, for proper treatment planning and effective dental care.
What Are the Benefits and Drawbacks of Cone-Beam CT in Repair of Endovascular Aneurysm?
The benefits and drawbacks of cone-beam CT are listed below:
Advantages -
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Decreased time for examination.
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Decreased patient movement artifact.
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Increased X-ray tube efficiency.
Disadvantages -
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Increased scattered radiation.
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Potential for the cone-beam artifact.
Does Cone-Beam CT Contain a High Risk of Radiation?
X-ray imaging, including dental CBCT, offers a rapid, non-invasive way to answer various clinical questions. CBCT images provide three-dimensional (3-D) information rather than two-dimensional (2-D) information from traditional X-rays. This helps in the diagnosis, treatment planning, and evaluation of certain medical conditions. Although the radiation dose from CBCT scans is generally lower than other CT scans, CBCT scans typically deliver more radiation than conventional X-rays. Because younger patients are more sensitive to radiation (that is, have higher cancer risk and mortality per unit dose of ionizing radiation) and have longer lives before adverse effects occur, concerns about radiation exposure are greater in younger patients.
What Is the Role of Cone-Beam CT in Repair of Endovascular Aneurysm?
CBCT is useful as an adjunct to complex aortic surgeries such as EVAR. Intraoperative application using fusion imaging limits the dose of contrast agent, and postoperative CBCT is of sufficient quality to assess successful aneurysm exclusion and detect early complications after EVAR. Using the information obtained from the CBCT after EVAR is completed can allow early intervention if problems arise and reduce the need for subsequent reintervention. There are at least three potential applications of CBCT in intra-aortic transplantation:
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Preoperative anatomic assessment and stent-graft sizing.
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Fusion imaging to guide device implantation and its use for postoperative assessment of successful aneurysm exclusion.
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One of the most potentially useful applications of CBCT is that of CT Images and fluoroscopy, similar to conventional road-mapping techniques. Intraoperative CBCT images can be registered or fused with preoperative multidetector computed tomography (MDCT), and MDCT images can be overlaid on live fluoroscopic images. The overlaid image is updated with the correct projection according to the arc angle of the C-arm. There is little information regarding the usefulness of this technique in treating aortic aneurysms or complex aortic disease.
CBCT is an extremely valuable addition to the endovascular suite and to the treatment of complex routine aortic disease. In the preoperative environment, it can be used to identify medical conditions and accurately plan treatment. Intraoperative use to guide the precise placement of endovascular devices can reduce the contrast media dose, ultimately shortening surgery and fluoroscopy times. This improves overall safety for patients and surgeons. Finally, CBCT seems to detect successful repair as easily as follow-up MDCT. Intraoperative use may reduce reintervention rates after procedures such as FEVAR, but this has not yet been shown. Further studies evaluating more patients may demonstrate the valuable features of this technology in evolution.
Conclusion:
Imaging is important in all stages of endovascular repair of abdominal aortic aneurysms (EVAR). When performing complex EVAR for proximal, superior, and thoracoabdominal aortic aneurysms, preoperative planning and postoperative follow-up rely heavily on advanced imaging techniques to address structural stent-graft issues. The advent of cone-beam computed tomography (CBCT) and nuclear fusion technology could significantly ameliorate these problems. CBCT produces a volumetric data set that can be reformatted like a standard CT examination. This improves the detection and localization of endoleaks and stent-graft-related problems, allowing them to be addressed intraoperatively. Further, the use of CBCT has proven beneficial in past cases of endovascular aneurysm repair surgery.
