Table 2. CTASI rHU values in ASPECTS regions with CT Perfusion–based ischemic core or penumbra or without CT perfusion–based hypoperfusion.

Location	rHU for ASPECTS Regions with CT Perfusion–based Core		n	rHU for ASPECTS Regions with CT Perfusion–based Penumbra		n	rHU for ASPECTS Regions without CT Perfusion–based Hypoperfusion		n	P Value Penumbra vs. Core	P Value No Deficit vs. Core	P Value No Deficit vs. Penumbra
C	0.828	(0.808–0.861)	19	0.875	(0.821–0.924)	20	0.963	(0.936–0.985)	40	0.067	<0.001	<0.001
IC	0.890	(0.876–0.904)	22	0.882	(0.860–0.919)	16	0.968	(0.936–0.997)	41	0.68	<0.001	<0.001
INS	0.785	(0.734–0.836)	46	0.831	(0.779–0.876)	29	0.970	(0.936–0.986)	4	0.04	<0.001	0.006
L	0.799	(0.774–0.834)	27	0.817	(0.796–0.900)	13	0.951	(0.910–0.986)	39	0.10	<0.001	<0.001
M1	0.889	(0.847–0.930)	21	0.920	(0.896–0.952)	49	0.966	(0.941–0.993)	9	0.01	<0.001	0.003
M2	0.852	(0.828–0.885)	30	0.901	(0.866–0.930)	46	0.971	(0.946–1.028)	3	0.006	0.006	0.009
M3	0.946	(0.929–0.985)	11	0.966	(0.942–0.989)	52	1.000	(0.988–1.017)	16	0.23	0.001	<0.001
M4	0.945	(0.921–0.969)	19	0.965	(0.946–0.983)	45	0.978	(0.959–1.013)	15	0.07	0.003	0.04
M5	0.912	(0.882–0.947)	32	0.915	(0.893–0.938)	44	1.009	(0.928–1.028)	3	0.67	0.082	0.08
M6	0.937	(0.920–0.945)	17	0.975	(0.939–0.987)	50	0.995	(0.983–1.040)	12	0.01	<0.001	0.001

rHU values are displayed as median (interquartile range). Ischemic core was defined as ischemic change on the parametric cerebral blood flow map as well as cerebral blood volume map. Penumbra was defined as ischemia on the cerebral blood flow maps without matching changes on cerebral blood volume maps. C indicates caudate nucleus; IC, internal capsule; INS, insula; L, lentiform nucleus; M1-M6, cortical regions of the ASPECTS score; rHU, relative Hounsfield Units; ASPECTS, Alberta Stroke Program Early CT Score. P Values <0.05 indicate statistical significance. Bold values indicate significance after correction for multiple comparisons using Bonferroni’s method.