WSO December 2023 – Issue 3 - 1205

Suzuki et al.
1205
Table 1. Patient characteristics.
n = 298
Age (years), median (IQR)
Male sex, no. (%)
Medical historya
Hypertension, no. (%)
Dyslipidemia, no. (%)
Diabetes mellitus, no. (%)
Atrial fibrillation, no. (%)
Smoking, no. (%)
NIHSS scoreb at admission, median (IQR)
Onset-to-door time (min), median (IQR)
Door-to-imaging time (min), median (IQR)
Occluded artery by MRA/CTA
ICA, no. (%)
M1, no. (%)
M2 or M3, no. (%)
A1, no. (%)
Infarct volume (mL), median (IQR)
Intravenous thrombolysis (alteplase 0.6 mg/
kg), no. (%)
75 (67-82)
194 (65)
187 (63)
99 (33)
63 (21)
144 (48)
111 (37)
15 (9-21)
150 (55-299)
22 (7-32)
81 (27)
128 (43)
93 (31)
4 (1)
11 (3-37)
108 (36)
IQR, interquartile range; NIHSS, National Institutes of Health Stroke
Scale; MRA, magnetic resonance angiography; CTA, computed
tomography angiography; ICA, internal carotid artery; M1, sphenoidal or
horizontal segment of the middle cerebral artery; M2, insular segment
of the middle cerebral artery; M3, opercular segment of the middle
cerebral artery; A1, segment of the anterior cerebral artery.
aMedical history was based on self-report, with the exception of the
presence of atrial fibrillation, which was based on medical history and
findings on electrocardiography performed at admission.
bScores on the NIHSS range from 0 to 42, with higher scores indicating
more severe neurologic deficits.
conventional and detailed DWI-ASPECTS ⩽6, the rate of
favorable outcomes was 43 (32%) in the conventional
group and 14 (19%) in the detailed DWI-ASPECTS group
(P = 0.052). However, the rate of favorable outcomes was
not different between conventional and detailed DWIASPECTS
>6 (103 (63%) vs. 132 (59%); P = 0.46).
Next, 134 patients with conventional DWI-ASPECTS
⩽6 were divided into two groups according to their detailed
DWI-ASPECTS. Of these 134 patients, the rate of favorable
outcomes was higher in patients with a detailed DWIASPECTS
>6 than in those with a score ⩽6 (29 (48%) vs.
14 (19%); P < 0.01). In addition, the ischemic core volume
was smaller in patients with a detailed DWI-ASPECTS >6
than in those with a score ⩽6 (22 (12-36) vs. 64 (41-88)
mL; P < 0.01; Figure 5).
Figure 3. Association between conventional DWIASPECTS
(x-axis) and detailed DWI-ASPECTS (y-axis) in
the overall study population. The detailed DWI-ASPECTS is
significantly higher than the conventional DWI-ASPECTS (8
(7-9) vs. 7 (5-9) P < 0.01).
Discussion
This study had two major findings. First, we developed a
novel method (detailed DWI-ASPECTS) that more closely
approximates the infarct core volume than the conventional
DWI-ASPECTS. Second, the detailed DWI-ASPECTS was
associated with clinical outcomes and was particularly effective
in patients with low conventional DWI-ASPECTS.
In ASPECTS using CT scans, the accuracy of detecting
acute ischemic lesions varies with imaging acquisition
details and interpreter subspecialty.17-19 DWI-ASPECTS
is shown to be more accurate than CT for localizing
ischemic lesions.20 De Margerie-Mellon et al.21 reported
that DWI-ASPECTS <4 or ⩾7 in patients with AIS can
be used as reliable surrogates of ischemic volumes >100
or <70 mL, respectively. Yoshimoto et al.22 showed a
strong negative correlation between DWI-ASPECTS and
ischemic volume on DWI. However, the divergence
between the DWI-ASPECTS and the ischemic volume
was significant when the score was ⩽6 and especially so
when ⩽4. They indicated that a small volume lesion
involving some of the 10 regions could lead to a low
DWI-ASPECTS. In contrast, the negative correlation of
the detailed DWI-ASPECTS was superior to conventional
DWI-ASPECTS even if the score was ⩽6 because small
volume lesions were not counted.
Ischemic core volume is an independent prognostic factor
in patients with AIS treated with recanalization therapy.23,24
Recently, the HERMES collaboration data showed that the
treatment effect of EVT was significant when the ischemic
core volume was <50 mL and mRS was ⩽3.25 The imaging
International Journal of Stroke, 18(10)
WSO December 2023 – Issue 3

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