Article Figures & Data
Figures
- Fig 1.
Imaging plane for arterial spin labeling method. We used three imaging planes: plane A, sagittal plane; plane B, 10-degree laterally tilted sagittal plane; plane C, 20-degree laterally tilted sagittal plane. All three imaging planes included the internal carotid artery top. ACA is located on the medial side of the imaging plane, and MCA is located on the lateral side. In the frontal lobe, plane A includes the superior frontal gyrus and plane C includes the middle frontal gyrus. Plane B is located around the superior frontal sulcus in most cases.
- Fig 2.
Images of a 50-year-old man with right internal carotid artery-posterior communicating artery aneurysm. Area with perfusion from the medial side is displayed by orange gradation, and area with perfusion from the lateral side is displayed by blue gradation. Three imaging planes were set up.
A, Plane A, sagittal plane, including internal carotid artery top. On plane A, the orange area (indicating perfusion from the ACA) is dominant (ratio of ACA area, 82%).
B, Plane B, 10-degree laterally tilted sagittal plane, including internal carotid artery top. On plane B, the blue area (indicating perfusion from the MCA) is becoming dominant (ratio of ACA area, 54%).
C, Plane C, 20-degree laterally tilted sagittal plane, including internal carotid artery top. On plane C, which is located near the superior frontal sulcus, the blue area is dominant (ratio of ACA area, 44%). Color scale shows P values.
D−F, Corresponding half Fourier single shot turbo spin-echo images are shown.
G, Digital subtration angiogram shows watershed (arrow) located in the middle of the middle frontal gyrus.
- Fig 3.
Images of a 45-year-old man with MCA stenosis at the horizontal part.
A, On plane A, area with ACA perfusion is 87%, which is similar to the ratio of the patient whose images are shown in Figure 2.
B and C, Tilted plane, however, shows that area with ACA perfusion did not diminish as in participants without MCA stenosis (70% on plane B and 69% on plane C). Color scale shows P values.
D, Digital subtraction angiogram shows that territory of ACA has spread into the lateral part of middle frontal gyrus, indicating lateral shift of watershed area (arrow).
- Fig 4.
Images of a 70-year-old man with MCA occlusion at horizontal part. Digital subtraction angiogram (D) shows that territory of ACA has spread wide into the lateral area (arrow). Area with ACA perfusion is larger in the tilted plane than in the images shown in Figures 2 and 3 (86% on plane A, 78% on plane B, and 79% on plane C). Color scale shows t values.
- Fig 5.
Percentage of area with ACA perfusion in participants with intact MCAs and with MCA stenosis or occlusion. In participants with intact MCAs, as the imaging plane shifts to the lateral side, the areas with ACA perfusion become smaller. In participants with MCA stenosis or occlusion, the area with ACA perfusion is larger than in participants with intact MCAs.
