Loss of Interhemispheric Connectivity in Patients with Lacunar Infarction Reflected by Diffusion-Weighted MR Imaging and Single-Photon Emission CT
Makiko Ishihara,a,
Shin-ichiro Kumitaa,
Hiromitsu Hayashia and
Tatsuo Kumazakia
a From the Department of Radiology, Nippon Medical School, 1–1–5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.
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FIG 1. A representative level of calculated ADC maps. ROIs, placed on the anterior and posterior corpus callosum and optic radiation, are 100 to 200 pixels each and the same in contour between the two maps.
A, ADC
B, ADC
C, A scheme for regional data extraction from these maps.
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FIG 2. A–D, A representative series of binary SPECT scans showing masking levels of 60% (A), 65% (B), and 70% (C) of the maximal counts and the original SPECT scan (D). As the masking level increased, the number of masked pixels of relatively low counts also increased
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FIG 3. An explanation of how the ACV, determined as the ratio of the number of pixels above the 80% masking level to the number above the 70% level, is validated. In this setting, the ACVs derived from the eight cortical areas should be homogeneous, because the actual tracer accumulation in the cortical area is uniform regardless of the regions.
A, Phantom MR image.
B, Phantom 123I-IMP SPECT scan.
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FIG 4. A and B, A representation of regional data extraction from one of the original SPECT scans. ROIs are specified at the superior frontal lobe and the parietal lobe (A), and the inferior frontal lobe and the temporal lobe (B), so as not to include the primary sensorimotor area, mesial temporal lobe, or insula. The ROIs are superimposed on ACV maps
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FIG 5. Correlations between the regional ACV and the MMSE scores. Individual ACVs in the superior and inferior frontal regions were well correlated with the MMSE score (superior frontal: r = .89, P < .05; inferior frontal, r = .71, P < .05).
Left upper, superior frontal.
Right upper, inferior frontal.
Left lower, parietal.
Right lower, temporal.
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FIG 6. Correlations between the regional AR of the corpus callosum and the ACV of the frontal areas. The AR in the anterior corpus callosum is strongly correlated with the frontal ACVs (superior frontal: r = .86, P < .0001; inferior frontal: r = .79, P < .0005). However, there are insignificant trends toward correlation between the AR in the anterior corpus callosum and the frontal ACVs within the patient group.
Left upper, anterior corpus callosum versus superior frontal region.
Right upper, anterior corpus callosum versus inferior frontal region.
Left lower, posterior corpus callosum versus superior frontal region.
Right lower, posterior corpus callosum versus inferior frontal region.
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