Ictal 99mTc-HMPAO SPECT in Alternating Hemiplegia Osamu Kanazawa, MD, Yoshiyuki Shirasaka, MD, Haruo Hattori, MD, Takehiko Okuno, MD, and Haruki Mikawa, MD 99mTc-hexamethylpropylenamine oxime (99mTcHMPAO) single-photon emission computed tomography (SPECT) was performed in a patient with alternating hemiplegia during 2 episodes of the disease. The regional cerebral blood flow patterns correlated with the clinical manifestations during both episodes. Hyperperfusion of the contralateral hemisphere was suggested by asymmetric 99mTc-HMPAO uptake, whereas symmetric 1231-N-isopropyl-p-iodoamphetamine uptake was detected during the interictal period. The results suggested that alternating hemiplegia in infants represents an atypical manifestation of epilepsy, despite the lack of paroxysmal electroencephalographic abnormalities during the episodes. 99mTc-HMPAO SPECT appears to be a useful method for detecting transient regional cerebral blood flow alterations during paroxysmal events because the tracer is rapidly available for emergencies and retains a fixed distribution for 5-8 hours, sufficient time to allow for SPECT acquisition. Kanazawa O, Shirasaka Y, Hattori H, Okuno T, Mikawa H. Icta199mTc-HMPAO SPECT in alternating hemiplegia. Pediatr Neurol 1991;7:121-4.
Introduction Alternating hemiplegia in infants was reported initially in 1971 by Verret and Steele [1]. This syndrome is a paroxysmal alternating tonic or atonic hemiplegic one that manifests during infancy [2]. Some later reports have been especially concerned about the possible relationship between hemiplegic migraine and alternating hemiplegia [3];
From the Department of Pediatrics; Faculty of Medicine; Kyoto University; Kyoto, Japan.
its similarity to epileptic seizure disorders [4] inevitably causes diagnostic difficulties. 99mTc-hexamethylpropylenamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) [5] was performed in a patient during 2 episodes of alternating hemiplegia. We report the results and possibly the first description of ictal regional cerebral blood flow (rCBF) as detected by 99mTcHMPAO in alternating hemiplegia. Methods 99mTc-HMPAO SPECT during the 2 episodes of alternating hemiplegia and 123I-N-isopropyl-p-iodoamphetamine (IMP) SPECT during the interictal period were used to detect rCBE Both 99mTc-HMPAO and IMP were obtained commercially (Amersham Co. Ltd. and Japan Mediphysics Co. Ltd., respectively). An intravenous line was inserted and the direct injection of 74 MBq (2 mCi) of 99mTc-HMPAO was performed during each episode. Because of a lack of cooperation, the patient received intravenous sedation with thiopental sodium several minutes after the 99mTc-HMPAO injection. Thirty minutes later, tomographic monitoring was begun using a multidetector scanner (SET030W; Shimazu Co., Kyoto, Japan) that provided 3 tomographic slices at 30 mm intervals simultaneously [5]. Each detector ring had 128 sodium iodine crystals. IMP 1 mCi was injected into a forearm vein between episodes after sedation with thiopental sodium and then cranial SPECT imaging was performed using the same scanner.
Case Report The patient was a 12-month-old boy with a history of a normal pregnancy and delivery, except for meconium-stained amniotic fluid. There was no family history of migraine or epilepsy. The patient was admiUed to the hospital because of facial pallor, irritability, and c-reactive protein positivity 1 day after birth. During this 1-month admission, postural abnormalities were observed; however, these improved spontaneously before discharge. There were no abnormal findings observed on cranial computed tomography (CT) and electroencephalography (EEG). The patient began to be habilitated by the Vojta method [6] as an at-risk infant with cerebral palsy and mental retardation at the age of 2 months. At 7 months of age, he began to crawl and there was no asymmetry of the parachute reflex. The episodes of hemiplegia began at 8 months of age; the first was a 2-day episode of left hand palsy, the second was right hand palsy, and the third was left hand palsy again. The interval between episodes was about 2 weeks. On the fourth occasion, quadriplegia developed for 2 days after about a l-month intervM. After the fourth episode, IMP-SPECT was performed during the interictal period. During each episode, consciousness was not disturbed, irritability was minimal, and feeding was not difficult. After a 2-month interval, left hand palsy appeared again, continued for 9 days, and diminished spontaneously. On the second day after the beginning of this long episode, 99mTc-HMPAO SPECT was performed initially. After reconfirming the presence of left hand palsy, 99rnTc-HMPAO 74 MBq (2 mCi; patient weight: about 9 kg) was injected into a left forearm vein. Immediately after the injection, thiopental sodium was injected to induce sleep and the rCBF scan was begun after 30 rain. About 40 days later, another left hand palsy appeared and 99mTcHMPAO SPECT was performed again using the same method as on the previous occasion. Although the interictal EEG occasionally demonstrated focal spike discharges in the left frontopolar region, ictal EEGs revealed no
Communications should be addressed to: Dr. Okuno; Department of Pediatrics; Faculty of Medicine; Kyoto University; 54 Shogoin-Kawaharacho, Sakyoku; Kyoto 606, Japan. Received July 9, 1990; accepted November 14, 1990.
Kanazawa et al: Alternating Hemiplegia
121
paroxysmal epileptic discharges (Fig 1). Cerebral angiography has not been performed. Laboratory examinations, including blood ammonia, blood amino acids, blood lactate and pyruvate, electrolytes, arterial gas analysis, and urine 5-HIAA, all were normal even during the episodes of alternating hemiplegia. Interictal evoked potentials till were within normal limits. After these SPECT examinations, administration of intermiUent doses of diazepam (5 rag) was begun on a trial basis because usually it is most effective in the rapid control of epileptic seizures. Tolerance develops wiih chronic administration of the drug; therefore, it appears In be suitable lor intermittent use in this type of patient wiih a long intericlal period. It appeared to be ineffective, however, in our patient and his psychomotor development was slightly retarded.
Results
Fp i-C ~ - ~ ' ~ ' ~ ' ~ ' ~ - ' - ~ ' ~ ' ~
.....- " ~ "
Fp ~ -C i~ ' ~ " ~ - ' ~ ' ~ " ~ C~-P3
'
. . . . . .
'
..... -.
'
. . . . . . . . .
F7-T3
Fs-TI T3-Ol Ti-02 EGG
Discussion Two hypotheses have been proposed to explain the mechanism underlying alternating hemiplegia. In one model, hypoperfusion due to intracranial vasospasm directly causes functional disturbances of motoneurons [3] which is almost the same mechanism as that found in adolescent basilar migraine. The other model, which is based on the observation that some alternating hemiplegic patients have epileptic discharges on EEG or even true epileptic seizures, proposes the same mechanism that operates in epilepsy [7], despite the lack of ictal discharges on scalp EEG recorded during each episode. Both hypotheses suggest that hypoperfusion of the contralateral hemisphere or sometimes other parts of the cortex between episodes would be a common finding [8-13]: however, the hypotheses propose completely different findings for rCBF during an episode, the former predicting hypoperfusion caused by vasoconstriction [9] and the latter predicting hyperperfusion caused by epileptic seizure discharges [ll,14]. Previous studies measuring rCBF by SPECT [9,151 and cerebral metabolism by positron emission iomography (PET) [8,16] revealed only an interictal decrease. Interictal IMP-SPECT findings in our patient were normal and the difference from other reports [15] is unknown. Some patients with epilepsy, however, demonstrate normal interictal findings for rCBF; the normal interictal rCBF findings in our patient may not be incompatible with those found in epileptic disorders 17,11-13]. Conversely, a common finding in these ictal 99mTcHMPAO SPECT studies was a relative increase in contralateral hemispheric rCBF. To our knowledge, there has been only I previous study of rCBF measured by SPECT during actual alternating hemiplegic episodes, which reported decreased rCBF in the frontal lobe, cerebellum, and brainstem only on the sagittal view, as well as findings almost the same as those observed between episodes [9].
PEDIATRIC NEUROLOGY
50 ~v
Fp+, -F 8~ ' - - ~ + - + - - ~ -
There were no localized regions of abnormal perfusion and no asymmetry in the interictal IMP-SPECT study (Fig 2A). Conversely, both ictal 99mTc-HMPAO SPECT studies revealed a similar pattern of asymmetric uptake (Figs 2B, 2C) with slight, relative hyperperfusion of the right temporo-parieto-occipital area.
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Figure 1. Ictal EEG revealed bilateral parieto-occipital dominant 4-5 Hz theta rhythmic waves without any epileptic" discharges.
That report was unclear as to whether there was hypoperfusion of the contralateral hemisphere. It has been speculated previously that contralateral partial cortical rCBF is changed during alternating hemiplegic episodes. Because they differed from results previously considered to be likely, our findings suggest that re-evaluation of the mechanism causing alternating hemiplegia is necessary. Our patient had relative hyperperfusion of the contralateral hemisphere during episodes of alternating hemiplegia, whereas there were no abnormal rCBF findings between episodes. Thus, it is suggested that alternating hemiplegia in our patient had the same underlying mechanism as epilepsy; however, that suggestion is not supported by findings on EEG obtained during the ictus which failed to demonstrate paroxysmal discharges. Children at his age are susceptible to West syndrome, a lype of epilepsy that is known to sometimes lack paroxysmal discharges during ictus [17]. There may be a special mechanism causing epileptic seizures without paroxysmal discharges in patients of this age. In addition, it is significant that the patient had cerebral palsy and mental retardation; the vast majority of infants with hemiplegic migraine or basilar artery migraine are otherwise neurologically normal [18]. Cerebral angiography, which unfortunately could not be performed during these episodes, may have provided valuable information regarding the pathogenesis of the child's alternating hemiplegia. On the basis of the SPECT results, we concluded that alternating hemiplegia in this patient may be an atypical form of status epilepticus which is interrupted by dormancy over a period of several days and that the seizures may be inhibitory or hemiparetic [7].
Figure 2. IMP or 99mTc-HMPAO SPECT imaging of horizontal brain sections 3.5 cm above the OM line. The red-to-blue areas are indicative of high-to-low IMP or 99m Tc-HMPAO uptake. (A) IMP-SPECT imaging demonstrated almost symmetric IMP uptake between episodes. (B,C) 99m TcHMPAO SPECT imaging during 2 episodes revealed asymmetric uptake. The common finding on these 2 occasions was a relative increase of 99mTc-HMPAO uptake in the right temporo-parieto-occipital region (arrowheads).
The recent d e v e l o p m e n t o f new radiopharmaceuticals has generated a wide interest in the possibility o f routine i m a g i n g o f r C B F with SPECT. 99mTc-HMPAO is a recently synthesized radiopharmaceutical that b e c o m e s distributed in the brain and reflects r C B F [19]. It is considered to be an almost optimal ligand that readily crosses the blood-brain barrier and retains a fixed distribution for at least 5-8 hours, sufficient t i m e to allow for S P E C T acquisition without a change in the r C B F pattern. This r a d i o p h a r m a c e u t i c a l has been used as a diagnostic aid in both children [20] and adults [5] with cerebral infarction, head trauma, and brain tumor. It reflected perfusion c h a n g e s with a high grade o f sensitivity, e v e n before any changes c o u l d be o b s e r v e d on C T in s o m e patients. In contrast to IMP, which is the most popular r a d i o p h a r m a c e u t i c a l [21], thyroid gland blocking is not necessary. The lack o f risk o f irradiation to the thyroid gland is an advantage, especially for children. B e c a u s e 99mTc-HMPAO can be rapidly m a d e for e m e r g e n c y use and retains a fixed distribution for a long period after a single bolus injection, it is c o n v e n i e n t to use in infants with n e u r o l o g i c conditions, such as alternating h e m i p l e g i a , especially w h e n it is also necessary to induce sleep in the patient. For these reasons, cranial S P E C T using 99mTcH M P A O should b e c o m e a valuable diagnostic test in infants and children presenting with suspected cerebrovascular disease.
We thank Drs. Naoki Matoba and Yoshiharu Yonekura of the Radiology Department for their helpful advice and kindness in the preparation of the radiologic records.
References
[1] Verret S, Steele JC. Ahemating hemiplegia in childhood: A report of eight patients with complicated migraine beginning in infancy. Pediatrics 1971;47:675-80. [2] Krfigeloh I, Aicardi J. Alternating hemiplegia in infants: Report of five cases. Dev Med Child Neurol 1980;22:784-91. [3] Hosking GP, Cavanagh NPC, Wilson J. Alternating hemiplegia: Complicated migraine of infancy. Arch Dis Child 1978;53:656-9. 14] Shirasaka Y, Ito M, Okuno T, Mikawa H, Yamori Y. Epileptic seizures difficult to differentiate from alternating hemiplegia in infants: A case report. Brain Dev 1990; 12:521-4. [5] Yonekura Y, Nishizuka S, Mukai T, et al. SPECT with [99mTc]d, l-hexamethyl-propylene amine oxide (HM-PAO) compares with regional cerebral blood flow measured by PET: Effects of linearization. J Cereb Blood Flow Metab 1988;8:$82-9. [6] Jones RB. The Vojta method of treating cerebral palsy. Physiotherapy 1975;61 : 112-3. [7] Hanson PA, Chodos R. Hemiparetic seizures. Neurology 1978; 28:920-3. [8] Nakamura Y, Nagano T, Mizuguchi M, et al. Alternating hemiplegia in infants: A case report. No To Hattatsu 1986;18:406-12. [9] Hattori H, Hashizuka S, Matsuoka O, Murata R, Ueda T. Alternating hemiplegia in infants: A case report with abnormal findings in ABR (auditory brain stem response) and SPECT (single photon emission CT). Jpn J Pediatr 1989;42:77-82. [10] Bonte FJ, Stokely EM, Devons MD, Horman RW. Single photon tomographic study of regional cerebral blood flow in epilepsy. Arch Neurol 1983;40:267-70. [ll] Denays R, Rubinstein M, Ham H, Piepsz A, No61 P. Single photon emission computed tomography in seizure disorders. Arch Dis Child 1988;63:1184-8. [12] Ryding E, Ros6n I, Elmqvist D, Ingvar DH. SPECT measurements with 99mTc-HMPAO in focal epilepsy. J Cereb Blood Flow Metab 1988;8:$95-100. [13] Rowe CC, Berkovic SF, Sia STB, et al. Localization of epileptic foci with postictal single photon emission computed tomography. Ann Neurol 1989:26:660-8. [14] Magistretti P, Uren R, Shomer D, Blume H, Holman B, Hill T. Emission tomographic scans of cerebral blood flow using 1231iodo-
Kanazawa et al: Alternating Hemiplegia
123
amphetamine in epilepsy. In: Raynuad C, ed. Nuclear medicine and biology. Proceedings of the Third World Congress of Nuclear Medicine and Biology. Paris: Pergamon Press, 1982; 139-43. [15] Sakuragawa N, Arima M, Matsumoto S. Nationwide investigation of actual condition about alternating hemiplegia of infants. J Jpn Pedialr Soc 1988;92:892-8. [16] Sakuragawa N, Malsuo T, Kimura S, et al. Alternating hemiplegia in infancy: Two case reports and reduced regional cerebral blood flow m riCO2 dynamic positron emission tomography. Brain Dev 1985:7:207. [171 F u k u y a m a Y. West syndrome. In: Akimoto H, Yamaguchi T, eds. Textbook of epileptnlogy. Tokyo: lwasaki Gakujutsu Shuppansha. 1984; 129-36.
124
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[18] Rothner AD. Migraine headaches. In: Swaiman KF, ed. Pediatric neurology: Principles and practice. St. Louis: CV Mosby, 1989: 643-8. [19] Neirinckx RD, Canning LR, Piper IM, et al. 'l'cchnctium-99nl I), I,-HM-PAO: A new radiopharmaccuticaI for SPECI' imaging of re gional cerebral blood pert'usion. J Ntlc] Med 1987:28: I ~)1-202. [21)] Shahar E, Gilday DL, I[wang PA. Cohen I:K, l,ambcrt R. Pediatric cerebrovascular disease: Alternations ot rcgmnal cerebral blood flow detected by Tc 99m-HMPAO SPECT. Arch Neurol 1990: 47:578 84. [21] Kuhl DE, Barrio JR, |lung SC, ct at. Quantilying local cerebral blond flow by N-isopropyl-p-[ 62-~11iodamphetamine (IMP)Iomography. J Nucl Med 1982:23:196-203.
Introduction Alternating hemiplegia in infants was reported initially in 1971 by Verret and Steele [1]. This syndrome is a paroxysmal alternating tonic or atonic hemiplegic one that manifests during infancy [2]. Some later reports have been especially concerned about the possible relationship between hemiplegic migraine and alternating hemiplegia [3];
From the Department of Pediatrics; Faculty of Medicine; Kyoto University; Kyoto, Japan.
its similarity to epileptic seizure disorders [4] inevitably causes diagnostic difficulties. 99mTc-hexamethylpropylenamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) [5] was performed in a patient during 2 episodes of alternating hemiplegia. We report the results and possibly the first description of ictal regional cerebral blood flow (rCBF) as detected by 99mTcHMPAO in alternating hemiplegia. Methods 99mTc-HMPAO SPECT during the 2 episodes of alternating hemiplegia and 123I-N-isopropyl-p-iodoamphetamine (IMP) SPECT during the interictal period were used to detect rCBE Both 99mTc-HMPAO and IMP were obtained commercially (Amersham Co. Ltd. and Japan Mediphysics Co. Ltd., respectively). An intravenous line was inserted and the direct injection of 74 MBq (2 mCi) of 99mTc-HMPAO was performed during each episode. Because of a lack of cooperation, the patient received intravenous sedation with thiopental sodium several minutes after the 99mTc-HMPAO injection. Thirty minutes later, tomographic monitoring was begun using a multidetector scanner (SET030W; Shimazu Co., Kyoto, Japan) that provided 3 tomographic slices at 30 mm intervals simultaneously [5]. Each detector ring had 128 sodium iodine crystals. IMP 1 mCi was injected into a forearm vein between episodes after sedation with thiopental sodium and then cranial SPECT imaging was performed using the same scanner.
Case Report The patient was a 12-month-old boy with a history of a normal pregnancy and delivery, except for meconium-stained amniotic fluid. There was no family history of migraine or epilepsy. The patient was admiUed to the hospital because of facial pallor, irritability, and c-reactive protein positivity 1 day after birth. During this 1-month admission, postural abnormalities were observed; however, these improved spontaneously before discharge. There were no abnormal findings observed on cranial computed tomography (CT) and electroencephalography (EEG). The patient began to be habilitated by the Vojta method [6] as an at-risk infant with cerebral palsy and mental retardation at the age of 2 months. At 7 months of age, he began to crawl and there was no asymmetry of the parachute reflex. The episodes of hemiplegia began at 8 months of age; the first was a 2-day episode of left hand palsy, the second was right hand palsy, and the third was left hand palsy again. The interval between episodes was about 2 weeks. On the fourth occasion, quadriplegia developed for 2 days after about a l-month intervM. After the fourth episode, IMP-SPECT was performed during the interictal period. During each episode, consciousness was not disturbed, irritability was minimal, and feeding was not difficult. After a 2-month interval, left hand palsy appeared again, continued for 9 days, and diminished spontaneously. On the second day after the beginning of this long episode, 99mTc-HMPAO SPECT was performed initially. After reconfirming the presence of left hand palsy, 99rnTc-HMPAO 74 MBq (2 mCi; patient weight: about 9 kg) was injected into a left forearm vein. Immediately after the injection, thiopental sodium was injected to induce sleep and the rCBF scan was begun after 30 rain. About 40 days later, another left hand palsy appeared and 99mTcHMPAO SPECT was performed again using the same method as on the previous occasion. Although the interictal EEG occasionally demonstrated focal spike discharges in the left frontopolar region, ictal EEGs revealed no
Communications should be addressed to: Dr. Okuno; Department of Pediatrics; Faculty of Medicine; Kyoto University; 54 Shogoin-Kawaharacho, Sakyoku; Kyoto 606, Japan. Received July 9, 1990; accepted November 14, 1990.
Kanazawa et al: Alternating Hemiplegia
121
paroxysmal epileptic discharges (Fig 1). Cerebral angiography has not been performed. Laboratory examinations, including blood ammonia, blood amino acids, blood lactate and pyruvate, electrolytes, arterial gas analysis, and urine 5-HIAA, all were normal even during the episodes of alternating hemiplegia. Interictal evoked potentials till were within normal limits. After these SPECT examinations, administration of intermiUent doses of diazepam (5 rag) was begun on a trial basis because usually it is most effective in the rapid control of epileptic seizures. Tolerance develops wiih chronic administration of the drug; therefore, it appears In be suitable lor intermittent use in this type of patient wiih a long intericlal period. It appeared to be ineffective, however, in our patient and his psychomotor development was slightly retarded.
Results
Fp i-C ~ - ~ ' ~ ' ~ ' ~ ' ~ - ' - ~ ' ~ ' ~
.....- " ~ "
Fp ~ -C i~ ' ~ " ~ - ' ~ ' ~ " ~ C~-P3
'
. . . . . .
'
..... -.
'
. . . . . . . . .
F7-T3
Fs-TI T3-Ol Ti-02 EGG
Discussion Two hypotheses have been proposed to explain the mechanism underlying alternating hemiplegia. In one model, hypoperfusion due to intracranial vasospasm directly causes functional disturbances of motoneurons [3] which is almost the same mechanism as that found in adolescent basilar migraine. The other model, which is based on the observation that some alternating hemiplegic patients have epileptic discharges on EEG or even true epileptic seizures, proposes the same mechanism that operates in epilepsy [7], despite the lack of ictal discharges on scalp EEG recorded during each episode. Both hypotheses suggest that hypoperfusion of the contralateral hemisphere or sometimes other parts of the cortex between episodes would be a common finding [8-13]: however, the hypotheses propose completely different findings for rCBF during an episode, the former predicting hypoperfusion caused by vasoconstriction [9] and the latter predicting hyperperfusion caused by epileptic seizure discharges [ll,14]. Previous studies measuring rCBF by SPECT [9,151 and cerebral metabolism by positron emission iomography (PET) [8,16] revealed only an interictal decrease. Interictal IMP-SPECT findings in our patient were normal and the difference from other reports [15] is unknown. Some patients with epilepsy, however, demonstrate normal interictal findings for rCBF; the normal interictal rCBF findings in our patient may not be incompatible with those found in epileptic disorders 17,11-13]. Conversely, a common finding in these ictal 99mTcHMPAO SPECT studies was a relative increase in contralateral hemispheric rCBF. To our knowledge, there has been only I previous study of rCBF measured by SPECT during actual alternating hemiplegic episodes, which reported decreased rCBF in the frontal lobe, cerebellum, and brainstem only on the sagittal view, as well as findings almost the same as those observed between episodes [9].
PEDIATRIC NEUROLOGY
50 ~v
Fp+, -F 8~ ' - - ~ + - + - - ~ -
There were no localized regions of abnormal perfusion and no asymmetry in the interictal IMP-SPECT study (Fig 2A). Conversely, both ictal 99mTc-HMPAO SPECT studies revealed a similar pattern of asymmetric uptake (Figs 2B, 2C) with slight, relative hyperperfusion of the right temporo-parieto-occipital area.
122
_ _ 1 1 sec
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Figure 1. Ictal EEG revealed bilateral parieto-occipital dominant 4-5 Hz theta rhythmic waves without any epileptic" discharges.
That report was unclear as to whether there was hypoperfusion of the contralateral hemisphere. It has been speculated previously that contralateral partial cortical rCBF is changed during alternating hemiplegic episodes. Because they differed from results previously considered to be likely, our findings suggest that re-evaluation of the mechanism causing alternating hemiplegia is necessary. Our patient had relative hyperperfusion of the contralateral hemisphere during episodes of alternating hemiplegia, whereas there were no abnormal rCBF findings between episodes. Thus, it is suggested that alternating hemiplegia in our patient had the same underlying mechanism as epilepsy; however, that suggestion is not supported by findings on EEG obtained during the ictus which failed to demonstrate paroxysmal discharges. Children at his age are susceptible to West syndrome, a lype of epilepsy that is known to sometimes lack paroxysmal discharges during ictus [17]. There may be a special mechanism causing epileptic seizures without paroxysmal discharges in patients of this age. In addition, it is significant that the patient had cerebral palsy and mental retardation; the vast majority of infants with hemiplegic migraine or basilar artery migraine are otherwise neurologically normal [18]. Cerebral angiography, which unfortunately could not be performed during these episodes, may have provided valuable information regarding the pathogenesis of the child's alternating hemiplegia. On the basis of the SPECT results, we concluded that alternating hemiplegia in this patient may be an atypical form of status epilepticus which is interrupted by dormancy over a period of several days and that the seizures may be inhibitory or hemiparetic [7].
Figure 2. IMP or 99mTc-HMPAO SPECT imaging of horizontal brain sections 3.5 cm above the OM line. The red-to-blue areas are indicative of high-to-low IMP or 99m Tc-HMPAO uptake. (A) IMP-SPECT imaging demonstrated almost symmetric IMP uptake between episodes. (B,C) 99m TcHMPAO SPECT imaging during 2 episodes revealed asymmetric uptake. The common finding on these 2 occasions was a relative increase of 99mTc-HMPAO uptake in the right temporo-parieto-occipital region (arrowheads).
The recent d e v e l o p m e n t o f new radiopharmaceuticals has generated a wide interest in the possibility o f routine i m a g i n g o f r C B F with SPECT. 99mTc-HMPAO is a recently synthesized radiopharmaceutical that b e c o m e s distributed in the brain and reflects r C B F [19]. It is considered to be an almost optimal ligand that readily crosses the blood-brain barrier and retains a fixed distribution for at least 5-8 hours, sufficient t i m e to allow for S P E C T acquisition without a change in the r C B F pattern. This r a d i o p h a r m a c e u t i c a l has been used as a diagnostic aid in both children [20] and adults [5] with cerebral infarction, head trauma, and brain tumor. It reflected perfusion c h a n g e s with a high grade o f sensitivity, e v e n before any changes c o u l d be o b s e r v e d on C T in s o m e patients. In contrast to IMP, which is the most popular r a d i o p h a r m a c e u t i c a l [21], thyroid gland blocking is not necessary. The lack o f risk o f irradiation to the thyroid gland is an advantage, especially for children. B e c a u s e 99mTc-HMPAO can be rapidly m a d e for e m e r g e n c y use and retains a fixed distribution for a long period after a single bolus injection, it is c o n v e n i e n t to use in infants with n e u r o l o g i c conditions, such as alternating h e m i p l e g i a , especially w h e n it is also necessary to induce sleep in the patient. For these reasons, cranial S P E C T using 99mTcH M P A O should b e c o m e a valuable diagnostic test in infants and children presenting with suspected cerebrovascular disease.
We thank Drs. Naoki Matoba and Yoshiharu Yonekura of the Radiology Department for their helpful advice and kindness in the preparation of the radiologic records.
References
[1] Verret S, Steele JC. Ahemating hemiplegia in childhood: A report of eight patients with complicated migraine beginning in infancy. Pediatrics 1971;47:675-80. [2] Krfigeloh I, Aicardi J. Alternating hemiplegia in infants: Report of five cases. Dev Med Child Neurol 1980;22:784-91. [3] Hosking GP, Cavanagh NPC, Wilson J. Alternating hemiplegia: Complicated migraine of infancy. Arch Dis Child 1978;53:656-9. 14] Shirasaka Y, Ito M, Okuno T, Mikawa H, Yamori Y. Epileptic seizures difficult to differentiate from alternating hemiplegia in infants: A case report. Brain Dev 1990; 12:521-4. [5] Yonekura Y, Nishizuka S, Mukai T, et al. SPECT with [99mTc]d, l-hexamethyl-propylene amine oxide (HM-PAO) compares with regional cerebral blood flow measured by PET: Effects of linearization. J Cereb Blood Flow Metab 1988;8:$82-9. [6] Jones RB. The Vojta method of treating cerebral palsy. Physiotherapy 1975;61 : 112-3. [7] Hanson PA, Chodos R. Hemiparetic seizures. Neurology 1978; 28:920-3. [8] Nakamura Y, Nagano T, Mizuguchi M, et al. Alternating hemiplegia in infants: A case report. No To Hattatsu 1986;18:406-12. [9] Hattori H, Hashizuka S, Matsuoka O, Murata R, Ueda T. Alternating hemiplegia in infants: A case report with abnormal findings in ABR (auditory brain stem response) and SPECT (single photon emission CT). Jpn J Pediatr 1989;42:77-82. [10] Bonte FJ, Stokely EM, Devons MD, Horman RW. Single photon tomographic study of regional cerebral blood flow in epilepsy. Arch Neurol 1983;40:267-70. [ll] Denays R, Rubinstein M, Ham H, Piepsz A, No61 P. Single photon emission computed tomography in seizure disorders. Arch Dis Child 1988;63:1184-8. [12] Ryding E, Ros6n I, Elmqvist D, Ingvar DH. SPECT measurements with 99mTc-HMPAO in focal epilepsy. J Cereb Blood Flow Metab 1988;8:$95-100. [13] Rowe CC, Berkovic SF, Sia STB, et al. Localization of epileptic foci with postictal single photon emission computed tomography. Ann Neurol 1989:26:660-8. [14] Magistretti P, Uren R, Shomer D, Blume H, Holman B, Hill T. Emission tomographic scans of cerebral blood flow using 1231iodo-
Kanazawa et al: Alternating Hemiplegia
123
amphetamine in epilepsy. In: Raynuad C, ed. Nuclear medicine and biology. Proceedings of the Third World Congress of Nuclear Medicine and Biology. Paris: Pergamon Press, 1982; 139-43. [15] Sakuragawa N, Arima M, Matsumoto S. Nationwide investigation of actual condition about alternating hemiplegia of infants. J Jpn Pedialr Soc 1988;92:892-8. [16] Sakuragawa N, Malsuo T, Kimura S, et al. Alternating hemiplegia in infancy: Two case reports and reduced regional cerebral blood flow m riCO2 dynamic positron emission tomography. Brain Dev 1985:7:207. [171 F u k u y a m a Y. West syndrome. In: Akimoto H, Yamaguchi T, eds. Textbook of epileptnlogy. Tokyo: lwasaki Gakujutsu Shuppansha. 1984; 129-36.
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PEDIATRIC NEUROLOGY
Vol. 7 No. 2
[18] Rothner AD. Migraine headaches. In: Swaiman KF, ed. Pediatric neurology: Principles and practice. St. Louis: CV Mosby, 1989: 643-8. [19] Neirinckx RD, Canning LR, Piper IM, et al. 'l'cchnctium-99nl I), I,-HM-PAO: A new radiopharmaccuticaI for SPECI' imaging of re gional cerebral blood pert'usion. J Ntlc] Med 1987:28: I ~)1-202. [21)] Shahar E, Gilday DL, I[wang PA. Cohen I:K, l,ambcrt R. Pediatric cerebrovascular disease: Alternations ot rcgmnal cerebral blood flow detected by Tc 99m-HMPAO SPECT. Arch Neurol 1990: 47:578 84. [21] Kuhl DE, Barrio JR, |lung SC, ct at. Quantilying local cerebral blond flow by N-isopropyl-p-[ 62-~11iodamphetamine (IMP)Iomography. J Nucl Med 1982:23:196-203.
