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MR evaluation of chronic aortic dissection
J M Pernes1, P Grenier, M T Desbleds
1Service de Radiologie Cardio-Vasculaire, Hôpital Broussais, Paris, France.
Abstract:
Thirty patients with suspected or known chronic aortic dissection were imaged with magnetic resonance (MR), CT, and angiography. Five of these patients had previously undergone surgical repair of the ascending aorta for a type A dissection. Magnetic resonance demonstrated an intimal flap and a double lumen in 25 cases. In four cases with a thrombosed false lumen, proved angiographically, an intimal flap and double channel were not seen. In two of four aortic dissections with a thrombosed false lumen, CT made the diagnosis by showing displaced intimal calcifications not visualized on MR. In one case the aortic dissection was made on CT and angiography but was not supported by MR which showed an aortic aneurysm, subsequently confirmed at surgery. Magnetic resonance, CT, and aortography differentiated between type A (nine patients) or B (20 patients) dissection in all cases and demonstrated extension into the abdominal aorta. Extension into the iliac arteries was seen on MR in three patients but missed in nine patients. Magnetic resonance differentiated the true and false lumen in all but one case. Thrombosis of the false channel was identified in four cases by a decrease in signal intensity on the second echo image. Cardiac gating and longitudinal contiguous sections seemed to be more suitable for appreciation of the relationships with arch vessels. Transverse contiguous slices allowed determination of the origin of celiac, mesenteric, and renal arteries from either the true or the false lumen. This study confirms that MR is an accurate and noninvasive method for the evaluation and follow-up of chronic aortic dissection, obviating the need for iodinated contrast media.
Insights
Magnetic resonance imaging (MRI) is an accurate, noninvasive tool for evaluating chronic aortic dissection, identifying intimal flaps and double lumens. It aids in differentiating dissection types and assessing abdominal aorta extension.
Area of Science:
- Cardiovascular Imaging
- Radiology
- Vascular Surgery
Background:
- Chronic aortic dissection requires accurate imaging for diagnosis and management.
- Distinguishing between true and false lumens is crucial for treatment planning.
Purpose of the Study:
- To evaluate the accuracy of magnetic resonance (MR) imaging compared to CT and angiography in diagnosing chronic aortic dissection.
- To assess the ability of MR to identify intimal flaps, double lumens, and extent of dissection.
Main Methods:
- Thirty patients with suspected or known chronic aortic dissection underwent imaging with MR, CT, and angiography.
- Analysis focused on the detection of intimal flaps, double lumens, thrombosed false lumens, and dissection extent.
Main Results:
- MR identified intimal flaps and double lumens in 25 cases.
- CT diagnosed two cases with thrombosed false lumens missed by MR, visualizing displaced intimal calcifications.
- All modalities differentiated between type A and B dissections and assessed abdominal aorta extension.
Conclusions:
- MR is an accurate and noninvasive method for evaluating and following chronic aortic dissection.
- MR obviates the need for iodinated contrast media, offering a safer alternative.
- Specific MR techniques like cardiac gating and contiguous slices improve visualization of aortic arch and visceral artery origins.