Neuroradiology (1995) 37:642-644
9 Springer-Verlag 1995

B. Okuda
H. Tachibana
M.Takeda
K. Kawabata
M. Sugita
M. Fukuchi

Received: 4 April 1994
Accepted: 12 July 1994

B. Okuda ( ~ ) . H. Tachibana. M. Takeda.
K. Kawabata. M. Sugita
Fifth Department of Internal Medicine,
Hyogo College of Medicine, 1-1,
Mukogawacho, Nishinomiya 663, Japan
M. Fukuchi
Department of Nuclear Medicine, Hyogo
College of Medicine, Nishinomiya, Japan

Focal cortical hypoperfusion in
corticobasal degeneration demonstrated
by three-dimensional surface display with
1231-iMP: a possible cause of apraxia

Abstract To clarify cortical lesions
responsible for apraxia in corticobasal d e g e n e r a t i o n (CBD), we reconstructed three-dimensional surface images f r o m single-photon
emission c o m p u t e d t o m o g r a p h y
(SPECT) data with N-isopropyl-p [I123]-iodoamphetamine in two patients with CBD. Both had limb-kinetic apraxia ( L K A ) and one also
had constructional apraxia (CA).
B o t h showed asymmetrical cortical
hypoperfusion in the perirolandic

Introduction
Corticobasal d e g e n e r a t i o n ( C B D ) is characterised by
asymmetrical higher cortical dysfunction and extrapyramidal signs, and the pathological changes are usually
asymmetrical [1, 2]. Since a r e p o r t f r o m Massachusetts
G e n e r a l Hospital [3], cases with clinically or pathologically diagnosed C B D have increased in n u m b e r [1, 2, 4].
A l t h o u g h patients with C B D frequently exhibit limbkinetic ( L K A ) and constructional apraxia (CA) [1, 2, 4],
the lesions responsible have not b e e n clarified. We rep o r t two patients with clinical CBD, in w h o m three-dimensional (3D) surface display g e n e r a t e d f r o m singlep h o t o n emission c o m p u t e d t o m o g r a p h y ( S P E C T ) demonstrated cortical perfusion defects corresponding to
the two types of apraxia.

area. The patient with C A had unilateral hypoperfusion in the posterior parietal area. Thus, cortical hypoperfusion in the perirolandic area
c o r r e s p o n d e d to L K A , and that in
the posterior parietal area to CA.

Key words Corticobasal
d e g e n e r a t i o n . Three-dimensional
surface display. A p r a x i a - Cortical
hypoperfusion 9 Single p h o t o n
emission c o m p u t e d t o m o g r a p h y

finger movements [5]. CA is defined as bimanual difficulty in putting together one-dimensional units so as to form two- or three-dimensional figures or patterns. CA was tested by copying line
drawings and stick constructions [6].
To assess cerebral blood flow (CBF), SPECTwith N-isopropylp[I-123]-iodoamphetamine (I23I-IMP) was conducted 30 rain after
administration of 123I-IMRA three-dimensional (3D) surface display was created from the axial SPECT images, using the STARCAM system computer, to show the cortical perfusion defect [7].
The threshold value for the surface boundary was 60 % of the global
maximum counts in the SPECT images. We adopted this threshold
value, since 11 control subjects without neurological disease (mean
age 67.6 + 10.6 years) rarely showed perfusion defects at 60 %
threshold.

Case reports
Case i

Materials and methods
The patients were diagnosed as having CBD on the basis of their
clinical course, neurological signs, and neuroimaging.
Higher cortical dysfunction in these patients were two types of
apraxia: LKA and CA. LKA is defined as a breakdown of previously skillful movements, and is manifest as difficulty with fine

A 71-year-old, left-handed man noticed a progressive movement
disorder of the left hand for 2 years. He had neither dementia nor
aphasia. He presented with bilateral LKA, especially on the left
side, without CA. Strength was preserved but pyramidal signs were
positive bilaterally. Muscle tone was increased moderately on the
left and mildly on the right. He showed neither cerebellar ataxia nor
involuntary movements; eye movements were preserved except for

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Fig. 1 Case 1. SPECF shows hypoperfused areas in the right
hemisphere

Fig.3 Case 2. SPECT shows hypoperfused areas in the left hemisphere

Fig.2 Case 1.3D surface display shows cortical hypoperfusion in
the bilateral perirolandic areas, more marked on the fight

Fig.4 Case 2. 3D surface display shows cortical hypoperfusion in
the left perirolandic and posterior parietal areas

impaired convergence. Brain MRI showed no abnormality. SPECT
disclosed hypoperfused areas in the right hemisphere, mainly in the
frontal lobe and to a lesser extent in the basal ganglia (Fig. 1). 3D
surface display demonstrated decreased CBF in the perirolandic
areas, markedly on the right and mildly on the left (Fig. 2).

Mental State Examination score 16/30), but not aphasic. She had
marked CA and mild bilateral LKA. Mild bilateral parkinsonism
was present. She also showed supranuclear vertical gaze palsy,
predominantly on downward gaze. Brain CT showed atrophic
changes in the left hemisphere. SPECT disclosed hypoperfused
areas in the left frontal and parietal lobes (Fig.3). 3D surface display revealed decreased CBF in the left perirolandic and posterior
parietal cortices (Fig. 4). Although there was no clinical asymmetry in this case, the distribution of cortical hypoperfusion
was consistent with that in previously reported cases [4]. These
findings suggested the diagnosis of CBD, but the possibility of as-

Case 2
A 65-year-old, fight-handed woman suffered from progressive unsteadiness of gait for 3 years. She was moderately demented (Mini-

644

sociated progressive supranuclear palsy could not be excluded [1,

8].

Discussion
These cases showed considerably asymmetrical cortical
hypoperfusion in the periro!andic or the posterior parietal areas or both. The perirolandic area comprises the
precentral and postcentral gyri, and the posterior parietal area the angular gyrus. Perirolandic cortical hypoperfusion can explain contralateral LKA, because
LKA has been attributed to a lesion in the sensorimotor
cortex [5]. As shown in case 2, a dominant hemisphere
lesion can cause bilateral LKA [4]. Other types of limb
apraxia such as ideomotor (IMA) or ideational (IA)
have been reported [2, 9], but were not found in these
patients with CBD. The discrepancy may suggest a certain heterogeneity of CBD, or it may be that motor
clumsiness due to LKA can induce apraxic disorders
resembling IMA or IA [4, 5]. Since the sensorimotor
cortex is predominantly involved in CBD [1, 2], we
think that LKA is the most frequent type of limb
apraxia in CBD. The lesion responsible for CA is more
complicated; CA can occur with bilateral lesions, or
right- or left-sided lesions [6], and the intrahemispheric
locus of the lesion responsible for CA remains obscure.
In general, lesions somewhere in the retrorolandic region tend to be associated with CA [6]. Our patient with
CA showed unilateral hypoperfusion in the parietal
cortex, particularly in the posterior part, including the
angular gyrus. Clinical and experimental studies have

demonstrated that the angular gyrus plays an important
role in visuospatial orientation [10, 11]. Thus the posterior parietal cortex, comprising the angular gyrus, appears to be the most likely site for CA in CBD.
Asymmetrical cerebral hypoperfusion or hypometabolism has been described in CBD [4, 12, 13]. Sawle et
al. [12] showed that fluorodopa uptake was reduced in
the striatum and cortical oxygen metabolism depressed
in the superior and posterior temporal, inferior parietal,
posterior frontal, and occipital association areas of the
cortex. Eidelberg et al. [13] demonstrated that glucose
metabolism was decreased in the thalamus, inferior parietal lobule, and hippocampus. In good agreement with
neuropathological findings [1-3, 14], these neuroimaging data disclosed the predilection for frontal and parietal cortical involvement in CBD. Our study revealed
more demarcated areas of cortical hypoperfusion, in the
perirolandic and posterior parietal cortex. The differences in distribution of hypoperfusion or hypometabolism may depend on methodological variations or the
duration of the illness.
Although various patterns of regional hypoperfusion
or hypometabolism have been reported in CBD, the lesions responsible for higher cortical dysfunction remain
to be clarified. 3D surface display appears useful for detecting the sites of lesions responsible for focal cortical
deficits. Asymmetrical multifocal hypoperfusion in the
perirolandic and posterior parietal cortices may favour
the diagnosis of CBD, particularly in the early stage.
Acknowledgement We thank H.Tanaka for neuropsychological
assessments.

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