Correlation between CT and Diffusion-Weighted Imaging of Acute Cerebral Ischemia in a Rat Model

American Journal of Neuroradiology

Download figure
Open in new tab
Download powerpoint
Fig 1.
Measurement of the region of interest for CT attenuation in ischemic and normal brain tissue. The region of interest is positioned in the inferolateral part of the hemisphere on each CT or MR image, 5 mm ventral to the external auditory canal.
Download figure
Open in new tab
Download powerpoint
Fig 2.
Longitudinal changes in acute ischemic lesions on CT, DWI, and the ADC map at each time point after MCA occlusion in a rat.
Download figure
Open in new tab
Download powerpoint
Fig 3.
Time courses of rCT, rDWI, and rADC after MCA occlusion. The rCT decreases gradually and rDWI increases gradually with time (P < .01, respectively). However, rADC rapidly decreases at 1 hour after MCA occlusion, and rADC shows no substantial change after 3 hours (P =. 33).
Download figure
Open in new tab
Download powerpoint
Fig 4.
Scatterplot of rCT and rDWI. Significant correlation occurs between rCT and rDWI in acute cerebral ischemia after 1, 3, 5, 7, or 9 hours of MCA occlusion. The rCT and rDWI are inversely correlated (P < .01, r = −0.592). The dotted line is the regression line for rCT and rDWI. One unit of rCT increase corresponds to 1.24 U of rDWI decrease.
Download figure
Open in new tab
Download powerpoint
Fig 5.
Scatterplot of dCT and dADC. No significant linear correlation occurs between dADC and dCT (P = .56) in acute cerebral ischemia after 1, 3, 5, 7, or 9 hours of MCA occlusion.

Table 1:

The mean values in CT, ADC, and DWI after MCA occlusion^a

Hour	rCT	rDWI	rADC	dCT^{^b}	dADC^{^c}
1	0.94 ± 0.04	1.40 ± 0.07	0.62 ± 0.08	2.00 ± 1.48	225.73 ± 52.60
3	0.87 ± 0.05	1.60 ± 0.10	0.55 ± 0.06	4.09 ± 1.76	268.18 ± 43.21
3	(P < .01)	(P < .01)	(P = .04)	(P = .01)	(P = .06)
5	0.81 ± 0.06	1.70 ± 0.13	0.56 ± 0.04	6.18 ± 2.44	262.45 ± 28.54
5	(P = .03)	(P < .01)	(P = .93)	(P = .04)	(P = .71)
7	0.73 ± 0.07	1.71 ± 0.23	0.58 ± 0.06	8.91 ± 2.51	250.55 ± 42.30
7	(P < .01)	(P = .82)	(P = .09)	(P < .01)	(P = .35)
9	0.71 ± 0.08	1.77 ± 0.28	0.57 ± 0.08	9.09 ± 2.39	257.73 ± 73.12
9	(P = .46)	(P = .39)	(P = .51)	(P = .84)	(P = .71)

a Data are mean ± SD. The figures in parentheses refer to the P values compared with the value of the previous time point in post hoc analysis of repeated-measure analysis.
b dCT is in Hounsfield units.
c dADC values are ×10⁻⁶ mm²/s.

Table 2:

The mean CNRs of CT attenuation, ADC value, and DWI signal intensity after MCA occlusion^a

Hour	CT (%)	P^{^b}	ADC (%)	P^{^c}	DWI (%)	P^{^d}
1	6.2 ± 4.4	<.001	38.5 ± 8.4	.453	39.9 ± 7.1	<.001
3	12.6 ± 4.5	<.001	44.8 ± 6.1	<.001	59.6 ± 9.8	<.001
5	18.9 ± 6.4	<.001	44.4 ± 4.0	<.001	69.9 ± 13.2	<.001
7	27.1 ± 6.5	<.001	41.8 ± 6.0	.004	71.2 ± 22.8	<.001
9	29.0 ± 8.0	.003	43.1 ± 7.9	.002	76.9 ± 28.2	<.001