Aortography

For more than 20 years, aortography has been the unique imaging modality for studying aortic pathology, and it has been considered to be the diagnostic standard to confirming or excluding the presence of traumatic aortic rupture49. Biplane cineangiography assures high temporal resolution images and accurate evaluation of the isthmic aorta by a single injection of 50 ml of contrast medium. The entire thoracic aorta as well as the intrathoracic portions of the brachiocephalic vessels should be visualized to exclude location of aortic rupture other than at the isthmus, occurring in 5% of clinical series. The diagnosis is based on the detection of the intimal/medial tear visible as a linear irregular filling defect within the lumen of the aorta (Figure 15.5). When the tear extends deep into the media, the pseudoaneurysm appears on the aortogram as

Figure 15.5. Aortography (left anterior oblique view). A longitudinal, subtle tear, extending within the lumen of the aorta, is visible.

a focal bulge in the column of contrast material. The combined findings that are highly specific for aortic rupture are a focal bulge with delayed washout of contrast material, and a linear filling defect at the level of the ligamentum arteriosum.

Focal bulge alone cannot be considered diagnostic of traumatic aortic rupture. A focal convexity, involving the opposite wall asymmetrically, may be present at the thoracic aortic isthmus in some 25% of cases due to ductus diverticulum and tends to be more prominent in older patients. It accounts for 1-2.8% of false positive results of aortography in the diagnosis of TAR50. Other abnormalities that can simulate TAR include atherosclerotic plaque, aor-titis, and streaming or mixing artefacts. A false negative diagnosis of rupture with angiography may occur up to 12% of cases51, due to poor opacifica-tion by contrast agents, inadequate projections, or thrombosis of the pouch. By design, small intimal tears or intimal intraparietal lesions cannot be visualized by angiography, as demonstrated in reports comparing angiography with high-resolution tomographic modalities as TEE, MRI, and CT39,52. Due to its invasive approach and contrast media administration, aortography generally has a complication rate of 1-2% of cases, which tends to be higher in acute patients. Kram49 reported 10.5% of complications in 76 victims of blunt chest trauma undergoing aortography, one of whom required blood transfusion for severe groin hemorrhage. Although it is difficult to demonstrate a precise cause and effect relationship, several cases of death during aortography have been reported22,51,53,54. Contrast media extravasation into the mediastinum or massive leakage from the aneurysm after injection of contrast media has even been documented by Del Rossi et al.51 and La Berge et al.53 Therefore, in the era of high-resolution noninvasive imaging modalities, aortography should not be recommended in polytraumatized patient with suspected TAR.

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