Neuroradiology (2012) 54:653–656
DOI 10.1007/s00234-012-1027-7

LETTER TO THE EDITOR

Ictal focal hyperperfusion demonstrated by arterial
spin-labeling perfusion MRI in partial epilepsy status
Makoto Oishi & Go Ishida & Ken Morii &
Kenji Hasegawa & Mitsuya Sato & Yukihiko Fujii

Received: 29 February 2012 / Accepted: 7 March 2012 / Published online: 16 March 2012
# Springer-Verlag 2012

Dear Sir,
Pulsed arterial spin-labeling (PASL) perfusion magnetic
resonance imaging (MRI) is a noninvasive method of measuring regional cerebral blood flow (rCBF) without contrast
medium and has been routinely applied in cerebrovascular
diseases as a cerebral perfusion measurement [1]. In partial
epilepsy, ictal cortical hyperperfusion is believed to be a
useful marker for identifying epileptogenic zone, and singlephoton emission computed tomography (SPECT) is commonly used for evaluating differences between interictal and
ictal cerebral perfusions. Few reports have described hemodynamic changes detected by PASL in interictal [2–4] and
peri-ictal states [5, 6]. Recently, we had a rare opportunity to
conduct PASL imaging and also diffusion-weighted imaging (DWI) of a patient both in partial epilepsy status (PES)
and during the interictal state.
M. Oishi : Y. Fujii
Department of Neurosurgery, Brain Research Institute,
Niigata University,
Niigata, Japan
G. Ishida
Department of Clinical Radiology,
Shinjinkai Kita-Nihon No-Shinkei Geka Hospital,
Niigata, Japan
M. Oishi : K. Morii : K. Hasegawa : M. Sato
Department of Neurosurgery,
Shinjinkai Kita-Nihon No-Shinkei Geka Hospital,
Niigata, Japan
M. Oishi (*)
Department of Neurosurgery, Brain Research Institute,
Niigata University,
1-757 Asahimachidori, Chuo-Ku,
Niigata 951-8585, Japan
e-mail: mac.oishi@me.com

Our patient, a 25-year-old man with normal development
and no neurological deficits, had sometimes experienced a
short-term feeling of visual distortion in the left half of his
visual field since age 20 years. He had his first generalized
convulsion and was admitted to our hospital. One week
later, he complained of frequent occurrences of blurred
vision or elementary visual hallucinations like flickering
lights in the left half of his visual field, sometimes accompanied by rotating his head to the left. An electroencephalogram (EEG) recorded three ictal events during 30 min.
The ictal pattern showed rhythmic bursting epileptic activities arising from the right occipital region, gradually reaching high amplitude and spreading to surrounding areas
within approximately 2 min and then finished without generalizing (Fig. 1a). He presented with seizures at a frequency
of five to six times per hour in the daytime, so-called PES.
After starting carbamazepine administration, the seizures
gradually decreased and had disappeared 3 days later. He
experienced left visual field loss for a few days even after
the seizures had disappeared but ultimately recovered from
this deficit.
MRI scans were performed on a 3 T MRI system
(MAGNETOM Verio; Siemens AG, Munich, Germany) on
the first day that frequent seizures occurred (Fig. 1b–d) and
1 week after the seizures had completely disappeared (Fig. 2).
Cortical evaluation by reversed Short T1 inversion recovery
(STIR) imaging indicated an anomaly consistent with a
cortical malformation in the right medial occipital region (Fig. 1b). PASL was performed with a pulsed
sequence, using QUIPSII perfusion mode [7] and the
following parameters: nine slices; FOV read, 300.0 mm;
FOV phase, 206.0; slice thickness, 10.0 mm; TE/TR/
Tl1/Tl2020/3,500/800/2,200 ms. PASL results were coregistered with FLAIR images. While focal hyperintense
signals on DWI were observed in the limited area of the

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Neuroradiology (2012) 54:653–656

Fig. 1 Examinations during
partial epilepsy status. Scalp
EEG during one seizure (a)
showed a focal seizure pattern
in the right occipital region.
Reversed Short T1 inversion
recovery (STIR) imaging (b)
shows a focal cortical anomaly
in the right medial occipital
cortex (yellow arrows).
Diffusion-weighted imaging
(DWI) (c) shows hyperintense
signals in the focal cortical area
(white arrows) corresponding to
the abnormal cortex on STIR.
Pulsed arterial spin-labeling
imaging (d) demonstrates
strong cortical hyperperfusion
in the medial to lateral occipital
cortices, much more widely
distributed than the abnormal
signal alteration on DWI

cortical lesion during PES, PASL demonstrated strong
and extensive hyperperfusion in the right occipital lobe
with the center at the cortical lesion (Fig. 1c, d). After
the seizures had completely disappeared, hyperintense

signals on DWI also disappeared and PASL demonstrated instead hypoperfusion of the cortical lesion in the
right medial occipital area as compared to the same
region of the contralateral side (Fig. 2).

Neuroradiology (2012) 54:653–656

Fig. 2 MRI in the interictal state. Hyperintense signals on diffusionweighted imaging during partial epilepsy status have completely
disappeared (a). Pulsed arterial spin-labeling imaging (b) also
shows a change to relative hypoperfusion in the area presenting a cortical
anomaly, as compared with the same region in the contralateral
hemisphere

Some authors have investigated the utility of focal interictal perfusion abnormalities shown by PASL as a marker
for localizing the epileptic focus in partial epilepsy [2–4].
They observed significant correlations between the interictal
hypoperfusion demonstrated by PASL and the results of
positron emission tomography or SPECT imaging in the
ictal period. We found only two reports presenting PASL
studies relating to the peri-ictal state; one was obtained
immediately after the seizure [5], while in the other, the
seizure incidentally occurred while scanning was ongoing,
immediately after the scanning the PASL sequence [6].
Although such peri-ictal findings were valuable, perfusion
alterations on PASL imaging between peri-ictal and interictal conditions had relatively little impact in achieving
visual distinction unless a statistical analysis was conducted
[5]. In our case, PASL imaging during PES showed strong
focal hyperperfusion of the region corresponding to the
anatomical and physiological epileptic focus and also
obtained clear contrast to the relative hypoperfusion in the
interictal state. To our knowledge, this is the first clear
demonstration of focal hyperperfusion relating to PES by
PASL imaging. Furthermore, a discrepancy between cortical
extents of perfusion alterations and cytotoxic changes in
PES, based on comparing PASL and DWI findings, was
also obtained.

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In epilepsy status presenting as repeated or continuous
seizures, the epileptic cortical areas should be in an electrophysiologically extreme state consisting of seizure-induced
vascular alterations and neuroinflammation which play roles
in persistent epileptogenesis. The prolonged and extraordinary activation of neurons in the affected area increases
glucose and oxygen requirements, thereby causing compensatory regional hyperperfusion. When the hyperperfusion is
no longer sufficient to supply the hyperactive cortical area,
pathophysiological changes leading to cytotoxic edema will
occur and are known to appear as an abnormal signal on
DWI [8, 9]. The MRI findings of low apparent diffusion
coefficient (ADC) and high signals on DWI in status epilepticus can resemble those of acute ischemic stroke, indicating changes attributable to both cytotoxic and vasogenic
edema [8–11]. The spatiotemporal correlation of regional
changes on DWI and electroclinical findings indicates that
the transient hemodynamic alteration is dependent on electrical activity during prolonged epileptic activity [8–11].
Although such ictal changes on DWI were reversible in
most cases on follow-up imaging studies and there were
no permanent neurological deficits, they occasionally
resulted in regional brain atrophy [9]. Predicting irreversible
change from the radiological findings in PES is still controversial. It is obviously necessary to ascertain the critical
border of perfusion alterations causing the vasogenic and
cytotoxic changes shown on DWI. The large and clear
discrepancy between the focal signal change on DWI and
strong hyperperfusion on PASL imaging during PES in our
patient was striking, and further systematic analyses of
similar experiences are anticipated to resolve this critical
issue.

Conflict of interest We declare that we have no conflict of interest.

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