An aortic aneurysm is a segmental enlargement of the diameter of the vascular lumen by more than 50% of the normal diameter of the vessel. In the thoracic aorta, it occurs most frequently in the ascending segment (60%), followed by the descending segment (35%), and most rarely in the aortic arch. The most important imaging tests for diagnosis are magnetic resonance angiography (MRA) and computed tomographic angiography (CTA). MRA is a non-invasive imaging method that allows the examination of the vasculature without ionising radiation. Three basic MRA imaging techniques are known, the time of flight technique, phase-contrast angiography and contrast-enhanced angiography. CTA is a non-invasive imaging method that uses an iodine contrast agent to image the vasculature. For both imaging methods, the rhythmic movement of the heart is the most difficult, which is why we use ECG gated imaging. Purpose: The aim of this thesis is to present a case of a patient diagnosed with a thoracic aortic aneurysm and to determine which of the imaging methods (MRA or CTA) is better in diagnosing the aneurysm and to present the advantages and disadvantages of both methods. Methods: We performed a retrospective study of a case who was diagnosed with an ascending thoracic aortic aneurysm by CTA and subsequently underwent MRA to control the size of the thoracic aorta. Results: The diameters of different regions of the thoracic aorta were measured by CTA and MRA. We found that all measurements were identical between the two imaging examinations, with only a deviation in the proximal aortic arch. Discussion and conclusion: We found that CTA and MRA are equally good for diagnosing thoracic aortic aneurysms. Despite the use of ionising radiation and contrast agent, CTA remains the gold standard for thoracic aortic imaging, mainly due to its lower cost, greater accessibility and speed of imaging, as the whole aorta can be imaged in one breath of the patient. However, non-contrast MRA is gaining an increasing role in the diagnosis and follow-up of aneurysms because it does not use ionising radiation. Its biggest disadvantage is the duration of the examination, but with the use of newer pulse sequences, the examination time is decreasing and thus it is becoming a better alternative to CTA. Both examinations are most limited by the rhythmic motion of the heart, which is why we use ECG gated imaging, which significantly reduces artefacts due to cardiac motion.
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