Journal of the Neurological Sciences 272 (2008) 183 – 185
www.elsevier.com/locate/jns

Short communication

Reversible diffusion-weighted lesion in a TIA patient without
arterial recanalization: A case report
Yuka Terasawa ⁎, Yasuyuki Iguchi, Kazumi Kimura, Kazuto Kobayashi,
Junya Aoki, Kensaku Shibazaki
Department of stroke medicine, Kawasaki medical school, 577 Matsushima Kurashiki-city Okayama, 701-0192 Japan
Received 24 February 2008; received in revised form 26 April 2008; accepted 29 April 2008
Available online 16 June 2008

Abstract
A 70-year-old man with right hemiparesis (NIHSS score 15) was admitted to our hospital 1 h after onset. Diffusion-weighted imaging
(DWI) revealed a hyperintense lesion in the left corona radiata and magnetic resonance angiography (MRA) revealed occlusion of the left
middle cerebral artery (MCA). At 2.5 h after onset, his neurological deficits dramatically improved (with NIHSS score change from 15 to 2).
Immediately thereafter, follow-up MRI revealed that the hyperintense lesion on DWI had disappeared, though the left MCA occlusion
remained. By the end of follow-up MRI examination, his neurological deficits had completely disappeared. We report here the patient with
transient ischemic attack with a reversible ischemic lesion on DWI without early arterial recanalization.
© 2008 Elsevier B.V. All rights reserved.
Keywords: Transient ischemic attack; Diffusion-weighted; Spectacular shrinking deficit

1. Introduction
Diffusion-weighted magnetic resonance imaging (DWI)
abnormalities have been found in the acute phase in several
patients with transient ischemic attack (TIA) [1–4]. In TIA
patients, early recanalization should result in disappearance
of neurological deficits and abnormalities on DWI. We
report here a TIA patient with a reversible ischemic lesion on
DWI without early arterial recanalization.
2. Case
A 70-year-old right-handed man was admitted to our
hospital after 1 h of weakness in the right arm and leg. His
past medical history was hypertension for 10 years and
hyperlipidemia not treated with medication. On physical
examination, his height was 168 cm and body weight

⁎ Corresponding author. Tel.: +81 86 462 1111; fax: +81 86 464 1128.
E-mail address: tera@med.kawasaki-m.ac.jp (Y. Terasawa).
0022-510X/$ - see front matter © 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jns.2008.04.033

65.5 kg. Body temperature was 36.6 °C, blood pressure 170/
104 mmHg, and heart rate 68 bpm with regular sinus rhythm.
No neck or orbital bruits were present, and peripheral arterial
pulsations were palpable bilaterally. The heart sounds were
clear without audible murmurs.
On neurological examination, he was alert. He could not
speak spontaneously, but could respond normally to all
commands. The pupils were round and equal, and light
reflexes were prompt bilaterally. Both eyes were in the
midline, and ocular movements were normal in all directions. A right central facial palsy was present. Motions of the
tongue, jaw, and palate were normal. The right arm exhibited
flaccid paralysis. Slight spontaneous movement remained in
the right lower extremity. Sensation was slightly impaired on
the right side. No extensor plantar response was present in
the right foot. The National Institutes of Health stroke scale
(NIHSS) score was 15 on admission.
Laboratory examinations on admission revealed a red
blood cell count of 388 × 104/mm3, hemoglobin 13.4 g/dl,
hematocrit 38.8%, white blood cell count 5400/mm3, platelets
17.7 × 104/mm3, D-dimer level b 0.5 (normal b 0.5 μg/ml) and

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Y. Terasawa et al. / Journal of the Neurological Sciences 272 (2008) 183–185

Fig. 1. On admission, DWI revealed a hyperintense lesion in the left corona radiata (A) and MRA revealed left middle cerebral artery (MCA) occlusion (B). At
2.5 h after onset, the hyperintense lesion in the left corona radiata on initial DWI had completely disappeared (C). Follow-up MRA revealed persistent MCA
occlusion (D). At 24 h after onset, DWI revealed multiple hyperintense lesions in the left MCA area (E) and the left MCA had completely recanalized (F).

level of thrombin-antithrombin III complex (TAT) 1.5 ng/ml
(normal b 3.0 ng/ml). No liver or renal dysfunction was noted.
Seventy minutes after onset, he was examined using a
1.5-tesla magnetic resonance imaging (MRI) unit (Signa
Echo Speed Horizon; GE Medical Systems, Milwaukee,
WI). DWI revealed a hyperintense lesion in the left corona
radiata (Fig. 1A). When we placed one small region of
interest (ROI) on the affected area and contralateral region
(mirror image) on initial DWI, the apparent diffusion
coefficient (ADC) was lower in the left corona radiata than
on the control side (0.52 × 10− 3 mm2/s on the left side and
0.70 × 10− 3 mm2/s on the right). Compared with the right
side, the decrement in ADC (ADC ratio) on the left side was
0.74. MR angiography (MRA) revealed an occlusion of the
left middle cerebral artery (MCA) (Fig. 2A).
We considered administration of intravenous thrombolysis with rt-PA. However, his neurological symptoms
dramatically improved from an NIHSS score of 15 to 2
within 40 min of arrival at the hospital, and he therefore did
not undergo thrombolysis. When we found the clinical
improvement of this patient, blood pressure was 166/
102 mm Hg. We performed follow-up MRI 2.5 h from
onset. The hyperintense lesion in the left corona radiata on
initial DWI had completely disappeared (Fig. 1C), but the
occlusion of the left MCA remained (Fig. 1D). By the end of
follow-up MRI examination, his neurological deficits
had recovered completely. We therefore diagnosed transient
ischemic attack (TIA).
At 24 h after onset, MRA demonstrated complete
recanalization of the left MCA. DWI revealed multiple
hyperintense lesions in the left MCA area, but he had no
symptoms. Holter 24-hour electrocardiography revealed

sinus rhythm without atrial fibrillation. Transesophageal
echocardiography revealed the presence of a patent foramen
ovale and atrial septal aneurysm. Carotid Doppler ultrasonography detected no arterial lesions. Although deep
venous thrombosis was absent in his lower extremities, it
appeared that TIA had contributed to paradoxical brain
embolism in association with a right-to-left shunt. Finally,
we considered him as clinical TIA because he had only
asymptomatic lesions on DWI.
3. Discussion
We have reported here a patient with TIA with a reversible
ischemic lesion on DWI without early arterial recanalization.
Dramatic neurological improvement immediately after
acute hemispheric stroke has been described as spectacular
shrinking deficit (SSD) following the rapid migration of an
embolus [5]. However, follow-up MRA revealed persistent
MCA occlusion despite dramatic neurological recovery. If
we had performed follow-up MRI only at 24 h after onset,
we would have suspected that the neurological improvement
was due in part to the arterial early recanalization, as in a
previous report [6].
In our case, the hyperintense lesion on initial DWI
disappeared on follow-up DWI study. At 24 h after onset,
DWI revealed multiple hyper-intense lesions in the affected
arterial territory consistent with MCA recanalization. Several
case series have reported that DWI hyperintense lesions
disappeared in the sub-acute phase after onset [3,4]. While 20
to 70% of TIA patients had abnormal DWI lesions on
admission [1–4], half of these lesions appear to have resolved
by the time of follow-up study [4]. Early recanalization might

Y. Terasawa et al. / Journal of the Neurological Sciences 272 (2008) 183–185

be thought to result in disappearance of abnormalities on
DWI. However, in our case, the occluded artery did not
reopen when the hyper-intense lesion on DWI disappeared.
We believe that collateral flow like a leptomeningeal
anastomosis developed immediately after arterial occlusion.
Low ADC ratio in the lesion is reported to be associated
with irreversible ischemia, with a cut-off value of 0.82 [7]. In
our patient, however, the ADC ratio was 0.74, inconsistent
with this previous report [7]. Our findings are thus also
inconsistent with the conclusion that low ADC value is
associated with permanent ischemia.
In conclusion, we have reported a patient with TIA without early recanalization of the occluded artery.
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