Association between Signal Hyperintensity on T1-Weighted MR Imaging of Carotid Plaques and Ipsilateral Ischemic Events
N. Yamadaa,
M. Higashia,
R. Otsubob,
T. Sakumaa,
N. Oyamab,
R. Tanakaa,
K. Iiharac,
H. Naritomia,
K. Minematsub and
H. Naitob
a Department of Radiology, Cerebrovascular Division, National Cardiovascular Center, Osaka, Japan
b Department of Medicine, National Cardiovascular Center, Osaka, Japan
c Department of Neurosurgery, National Cardiovascular Center, Osaka, Japan
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Fig 1. Volume of plaque imaging.
A, Maximum intensity projection for contrast MRA of the cervical arteries. Volume of plaque imaging with MPRAGE is indicated between the 2 transverse bars.
B, Near-coronal multiplanar reconstruction of MPRAGE.
C, Source image of MPRAGE 3 mm cranial to the right carotid bifurcation shows relatively homogeneous signal intensity in the neck.
D, Zoomed source image of MPRAGE demonstrates dark lumen of the right internal carotid artery (ICA) and the external carotid artery (ECA). Circle indicates region of interest placed in the SCM.
E, Zoomed source image of TOF MRA at the same position demonstrates bright lumen of the carotid arteries. Plaque of the ICA (asterisk) demonstrates signal hyperintensity. SCM, sternocleidomastoid muscle.
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Fig 2. Examples of classic carotid plaques.
A, An example of low signal intensity plaque. Top and bottom rows show 3 corresponding sections with 2.5-mm intervals of TOF MRA and MPRAGE, respectively. A 76-year-old man has left carotid artery stenosis and no history of ipsilateral ischemic events. The carotid plaque (arrows) displays no signal hyperintensity relative to the adjacent muscle.
B, An example of high signal intensity plaque. Top and bottom rows show 3 corresponding sections with 2.5-mm intervals in initial and follow-up MR imaging. A 58-year-old man experienced cerebral infarction in the territory of the right middle cerebral artery 12 days before initial MR imaging, which reveals a right carotid plaque with heterogeneous MPRAGE signal hyperintensity (top row). At 4 months after initial MR imaging, the patient again developed cerebral infarction in the right middle cerebral artery territory. Follow-up MR imaging at 5 months after initial MR imaging (bottom row) shows mild increase of MPRAGE high signal intensity region.
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Fig 3. Comparison of high signal intensity volume between successive MR imaging. Comparison was done 34 times between 2 successive MR imagings with high signal intensity in both or either of the 2 MR images. Median interval was 279 days (range, 10–1037 days). High signal intensity volume (mean ± SD) was 149 ± 182 mm3 at the initial MR imaging and 144 ± 217 mm3 at the repeat MR imaging. Paired t test displayed no significant change (P = .690). Broken lines indicate 4 carotid arteries associated with subsequent events within 1 year after initial MR imaging.
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