Table 1. Comparisons between Imaging-Negative Stroke Group and HARM without Diffusion Abnormalities Group Regarding Their Demographic and Clinical Characteristics.

	Imaging-Negative Stroke	HARM without Diffusion Abnormalities	P	Statistical Analysis
No. of cases	63	14	N/A	N/A
Mean age (range)	55.9 (42-88)	73.1 (53-92)	< 0.001	t test
Male	39 (61.9%)	8 (57.1%)	0.741	Pearson χ2
Median time-interval* (interquartile range)	3.5 (2.0-6.3)	2.5 (1.8-5.2)	0.460	Mann-Whitney
Median NIHSS at admission (interquartile range)	1.0 (0-2)	4.5 (2-8)	< 0.001	Mann-Whitney
Median NIHSS at 1 day (interquartile range)	0 (0)	0 (0-0.5)	0.010	Mann-Whitney
Median NIHSS at 7 day (interquartile range)	0 (0)	0 (0)	1	Mann-Whitney
Median mRS at 90 days (interquartile range)	0 (0)	0 (0)	1	Mann-Whitney
Hypertension	36 (57.1%)	11 (78.6%)	0.137	Pearson χ2
Diabetes	17 (27.0%)	5 (35.7%)	0.513	Pearson χ2
Hyperlipidemia	14 (22.2%)	2 (14.3%)	0.508	Pearson χ2
Atrial fibrillation	1 (1.6%)	0 (0.0%)	0.635	Pearson χ2
Smoking	24 (38.1%)	5 (35.7%)	0.868	Pearson χ2
Mean SBP at admission	158.0	159.3	0.886	t test
Mean DBP at admission	88.5	88.8	0.954	t test
Mean pulse rate at admission	79.6	72.6	0.172	t test
Median respiratory rate at admission	18	18	0.809	Mann-Whitney
Mean body temperature at admission	36.4	36.5	0.174	t test

^*Time interval between stroke and first MRI (in hours). DBP = diastolic blood pressure in mm Hg, HARM = hyperintense acute reperfusion marker, mRS = modified Rankin scale, NIHSS = National Institutes of Health Stroke Scale, N/A = not applicable, SBP = systolic blood pressure in mm Hg