Evolution of MR Contrast Enhancement Patterns during the First Week after Acute Ischemic Stroke
Jari O. Karonen
,a,
P. L. Kaarina Partanena,
Ritva L. Vanninena,
Pauli A. Vainioa and
Hannu J. Aronena
a From the Department of Clinical Radiology, Kuopio University Hospital (J.O.K., P.L.K.P., R.L.V., P.A.V., H.J.A.); and the Department of Radiology, Helsinki University Central Hospital (H.J.A.), Finland.
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FIG 1. 75-year-old woman with dysphasia and weakness in the right arm. The first MR examination (left column) was performed 8 hours after the onset of symptoms, the second MR examination (middle column) was performed on the second day, and the third MR examination (right column) 1 week after stroke. The slice positions are not exactly the same but this does not change the interpretation.
Top row, Unenhanced T1-weighted images (600/14/1) show progressing low signal mass effect of the infarcted tissue.
Middle row, Contrast-enhanced T1-weighted images (600/14/1) show intravascular enhancement over the infarct on the first and second days and moderate cortical and subcortical enhancement 1 week after stroke.
Bottom row, Diffusion-weighted trace images (4000/103/1, in raw image acquisition) show the extent of infarcted tissue as areas of increased signal intensity (bright) in the territory of the left middle cerebral artery.
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FIG 2. 63-year-old woman with right hemiparesis and aphasia. The first MR examination (left column) was performed 6.5 hours after the onset of symptoms, the second MR examination (middle column) was performed on the second day, and the third MR examination (right column) 1 week after stroke.
Top row, Unenhanced T1-weighted images (600/14/1) show progressing low signal mass effect of the infarcted tissue. Hemorrhagic transformation is detected as areas of increased signal intensity on the second day and at 1 week. The gyral pattern of increased signal intensity at 1 week may also represent cortical laminar necrosis.
Middle row, Contrast-enhanced T1-weighted images (600/14/1) show intravascular enhancement over the infarct on the first and second days. Moderate cortical and deep enhancement is detected at 1 week.
Bottom row, Diffusion-weighted trace images (4000/103/1, in raw image acquisition) show the extent of infarcted tissue as areas of increased signal intensity in the territory of the left middle cerebral artery. Hemorrhagic transformation is detected as a dark area due to the susceptibility effect of breakdown products of hemoglobin.
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FIG 3. 71-year-old man with left hemiparesis. The first MR examination (left column) was performed 15 hours after the onset of symptoms, the second MR examination (middle column) was performed on the second day, and the third MR examination (right column) 1 week after stroke.
Top row, Unenhanced T1-weighted images (600/14/1) show progressing low signal mass effect of the infarcted tissue. Hemorrhagic transformation is detected as areas of increased signal intensity on the second day and at 1 week.
Middle row, Contrast-enhanced T1-weighted images (600/14/1) show intravascular enhancement over the infarct on the first and second days. Moderate cortical and subcortical enhancement are detected on the second day. Intense parenchymal enhancement is detected in the infarct at 1 week.
Bottom row, Diffusion-weighted trace images (4000/103/1, in raw image acquisition) show the extent of infarcted tissue as areas of increased signal intensity in the territory of the right middle cerebral artery. Hemorrhagic transformation is detected as dark areas due to the susceptibility effect of the breakdown products of hemoglobin.
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FIG 4. 73-year-old man with left hemiparesis. The first MR examination (left column) was performed 23 hours after the onset of symptoms, the second MR examination (middle column) was performed on the second day, and the third MR examination (right column) 1 week after stroke.
Top row, Unenhanced T1-weighted images (600/14/1) are normal on the first and second days, but at 1 week, slightly increased signal intensity is observed in the cortex due to microhemorrhage or cortical laminar necrosis.
Middle row, Contrast-enhanced T1-weighted images (600/14/1) show intravascular enhancement over the infarct on the first day. Mild cortical enhancement is detected on the second day, progressing to intensive cortical enhancement at 1 week.
Bottom row, Diffusion-weighted trace images (4000/103/1, in raw image acquisition) show the extent of infarcted tissue as areas of increased signal intensity in the territory of the right middle cerebral artery.
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