Perfusion CT with Iodinated Contrast Material
James D. Eastwood1,
Michael H. Lev2 and
James M. Provenzale1
1 Department of Radiology, Division of Neuroradiology, Duke University Medical
Center, Box 3808, Durham, NC, 27710-3808.
2 Department of Radiology, Division of Neuroradiology, Massachusetts General
Hospital, 55 Fruit St., Boston, MA 02114.
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Fig. 1A. —54-year-old man with sudden onset of neck pain and right
hemiparesis. Superior maximum-density-projection image created from
whole-brain perfused-blood-volume CT angiography source images shows acute
left mid-M2 middle cerebral artery branch occlusion (arrow). Thrombus
was difficult to detect on source images alone. This reconstruction was
created at CT console in less than 1 min.
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Fig. 1B. —54-year-old man with sudden onset of neck pain and right
hemiparesis. Coronal curved reformatted image shows left internal carotid
artery skull base dissection (arrow), which likely represents source
of middle cerebral artery thromboembolus.
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Fig. 2A. —69-year-old woman 2 hr after onset of aphasia and right-sided
weakness. Focal hypodensity is difficult to discern on unenhanced CT scan of
brain.
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Fig. 2B. —69-year-old woman 2 hr after onset of aphasia and right-sided
weakness. Contrast-enhanced CT angiography axial source image acquired at same
time as A reveals large hypoenhancing area conforming to left middle
cerebral artery territory.
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Fig. 2C. —69-year-old woman 2 hr after onset of aphasia and right-sided
weakness. Diffusion-weighted MR image acquired 45 min after A and
B shows hyperintensity in left middle cerebral artery territory.
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Fig. 2D. —69-year-old woman 2 hr after onset of aphasia and right-sided
weakness. Unenhanced CT scan obtained for follow-up 34 hr after symptom onset
shows hypodensity corresponding to left middle cerebral artery territory. We
have found that final infarct volume on follow-up scans correlates well with
perfused-blood-volume perfusion CT lesion volume.
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Fig. 3A. —44-year-old man with onset of left hemiparesis 5 hr before
imaging. Single transverse CT source image from cine dynamic perfusion CT data
set (80 kVp, 200 mAs) shows substantial region of hypoattenuation in right
hemisphere. Anterior cerebral artery (green circle marked with
white arrow) and superior sagittal sinus (red circle marked
with black arrow) were chosen to serve as reference artery and
reference vein, respectively.
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Fig. 3B. —44-year-old man with onset of left hemiparesis 5 hr before
imaging. CT scan shows magnified arterial input region of interest (ROI)
placed on anterior cerebral artery. Small ROIs on order of 5-7 mm2
are typically used to reduce volume-averaging effects.
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Fig. 3C. —44-year-old man with onset of left hemiparesis 5 hr before
imaging. CT scan shows magnified venous outflow ROI in central part of
superior sagittal sinus. Venous outflow ROI represents "pure
blood" ROI to deconvolution analysis algorithm and is used to help
correct remainder of image for effects of volume averaging with nonvascular
tissue.
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Fig. 3D. —44-year-old man with onset of left hemiparesis 5 hr before
imaging. Graph shows time—attenuation curves for artery (green,
smaller curve) and vein (red, larger curve).
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Fig. 3E. —44-year-old man with onset of left hemiparesis 5 hr before
imaging. CT scan shows dynamic perfusion CT cerebral blood volume. Blue region
in right hemisphere represents tissue with cerebral blood volume less than 1.5
mL/100 g. Green regions represent blood volume of 1.5-3.0 mL/100 g and red
regions represent blood volume of greater than 3.0 mL/100 g.
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Fig. 3F. —44-year-old man with onset of left hemiparesis 5 hr before
imaging. CT scan shows cerebral blood flow. Blue regions in right hemisphere
represent tissue with cerebral blood flow less than 10 mL/100 g per minute.
Green regions represent blood flow of 10-20 mL/100 g per minute and red
regions represent blood flow of greater than 20 mL/100 g per minute.
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Fig. 3G. —44-year-old man with onset of left hemiparesis 5 hr before
imaging. CT scan shows mean transit time. Extensive red regions on right
represent tissue with mean transit time greater than 6 sec. Green regions
represent transit time of 3-6 sec and blue regions represent transit time of
less than 3 sec.
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Fig. 4. —74-year-old man with suspected stroke. Lateral scout image
from CT examination shows two levels chosen for single-detector perfusion CT.
First level (large arrows) corresponds to level of basal ganglia.
Second level (small arrows) is located more cephalad and helps to
increase coverage.
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Fig. 5A. —32-year-old woman with onset of left arm and face weakness 6
hr before scanning. Unenhanced CT image shows subtle hypodensity
(arrow) in right basal ganglia.
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Fig. 5B. —32-year-old woman with onset of left arm and face weakness 6
hr before scanning. Dynamic perfusion CT cerebral blood flow map shows
decreased blood flow in right insula and lateral basal ganglia (thin
arrow) and temporal lobe (thick arrows). Decreased blood flow in
range of 0-100 mL/100 g per minute is represented by blue.
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Fig. 5C. —32-year-old woman with onset of left arm and face weakness 6
hr before scanning. Mean transit time map calculated from same data as
B shows much more extensive region of abnormality. Increased mean
transit time greater than 6 sec is represented by red.
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Fig. 5D. —32-year-old woman with onset of left arm and face weakness 6
hr before scanning. Tissue time—attenuation curves. Iodinated contrast
material is slower to enter (thin arrow) and slower to wash out
(thick arrow) of right middle cerebral artery territory compared with
normal left middle cerebral artery territory. Inspection of such curves is not
usually done in clinical situation. Instead, computer algorithm computes
tissue values pixel by pixel to create perfusion maps such as those in
B.
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Fig. 5E. —32-year-old woman with onset of left arm and face weakness 6
hr before scanning. Unenhanced CT scan obtained 3 days after admission to
hospital shows final size of infarction in basal ganglia and small part of
temporal lobe (arrow).
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Copyright © 2003 by the American Roentgen Ray Society.
