Circulation. 1995;91:236-237
(Circulation. 1995;91:236-237.)
© 1995 American Heart Association, Inc.
Magnetic Resonance Phase Velocity Mapping in Dissecting Aortic Aneurysm
Demonstration of a Proximal Intimal Tear
Sandy M. Forbat, MBBS, MRCP;
Sara Thorne, MD, MRCP;
S. Richard Underwood, MA, MRCP;
Philip A. Poole-Wilson, MD, FRCP
From the Magnetic Resonance Unit (S.M.F., S.R.U.) and Department of
Cardiac Medicine (S.T., P.A.P.-W.), Royal Brompton Hospital, London, England.
Key Words: Cardiovascular Images • magnetic resonance imaging
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Introduction
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 Top
 Introduction
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A 57-year-old man with a history of a dissecting
aortic aneurysm
4 months previously was referred for magnetic resonance
imaging.
Transthoracic echocardiography, transesophageal
echocardiography,
and ultrafast computed tomography had demonstrated
the dissection
extending from the ascending aorta to the renal
arteries. The
point of entry was thought to be just above the aortic
valve,
but it had not been satisfactorily demonstrated by any of these
imaging
modalities. Magnetic resonance imaging was requested before
surgical
repair in an attempt to identify the proximal tear.
Gradient echo imaging (echo time, 14 ms) in the coronal plane clearly
demonstrated the intimal flap arising just above the aortic valve, but
it was not possible to identify the entry site (Fig 1
).
A series of transverse gradient echo cines were acquired to identify
any small area of signal loss at the intimal flap. At a level at which
there appeared to be some turbulent flow, an oblique coronal
gradient-echo cine was acquired across the intimal flap and through the
area of signal loss. The systolic frames of this cine demonstrated an
area of signal loss in the false lumen that was suggestive of a jet but
could have represented turbulent flow within the false lumen (Fig
2). Phase velocity mapping performed in the same plane
(echo time, 3.6 ms) clearly showed a jet from the true lumen to the
false lumen through an intimal tear measuring approximately 12 mm at a
level 3 cm above the aortic valve (Fig 3).
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Figure 1. Coronal gradient echocardiographic image (echo time,
14 ms) in diastole at the aortic valve showing the intimal flap and
true and false lumina. Left ventricle (LV), pulmonary artery (PA), and
aortic valve (AoV) are marked.
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Figure 2. Oblique coronal gradient echo image (echo time, 14
ms) in systole showing an area of signal loss (dashed arrow) appearing
to arise from the intimal flap (solid arrow).
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Figure 3. Phase velocity map (echo time, 3.6 ms) in the
same plane as Fig 2 with vertical velocity encoding. The image
has been
rotated clockwise to align the true lumen of the aorta vertically.
Velocity toward the top of the image appears in shades of gray. In
systole, there are two clear jets of blood flow, in the true lumen
(solid arrow) and through an intimal tear into the false lumen (dashed
arrow).
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Footnotes
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Reprint requests to Dr Sandy Forbat, Magnetic Resonance Unit,
Royal
Brompton Hospital, Sydney St, London SW3 6NP, England.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr,
MD, Chief, Department of Pathology, St Luke's Hospital and Texas Heart
Institute, and Clinical Professor of Pathology, University of Texas Medical
School and Baylor College of Medicine.
Circulation encourages readers to submit cardiovascular images to
Dr Hugh A. McAllister, Jr, St Luke's Episcopal Hospital and Texas Heart
Institute, 6720 Bertner, MC 4-265, Houston, TX 77030.
