Transient ischemic attack without self-awareness of symptoms witnessed by bystanders: analysis of the PROMISE-TIA registry.

BACKGROUND AND PURPOSE: A transient ischemic attack (TIA) can occur without self-awareness of symptoms. We aimed to investigate characteristics of patients with a tissue-based diagnosis of TIA but having no self-awareness of their symptoms and whose symptoms were witnessed by bystanders. METHODS: We used data from the multicenter registry of 1414 patients with a clinical diagnosis of TIA. For patients without evidence of ischemic lesions on imaging, clinical characteristics were compared between patients with and without self-awareness of their TIA symptoms. RESULTS: Among 896 patients (559 men, median age of 70 years), 59 (6.6%) were unaware of their TIA symptoms, but had those symptoms witnessed by bystanders. Patients without self-awareness of symptoms were older and more frequently female, and more likely to have previous history of stroke, premorbid disability, and atrial fibrillation, but less likely to have dyslipidemia than those with self-awareness. Patients without self-awareness of symptoms arrive at hospitals earlier than those with self-awareness (P < 0.001). ABCD2 score was higher in patients without self-awareness of symptoms than those with self-awareness (median 5 vs. 4, P = 0.002). Having no self-awareness of symptoms was a significant predictor of ischemic stroke within 1 year after adjustment for sex, ABCD2 score, and onset to arrival time (hazard ratio = 2.44, 95% confidential interval: 1.10-4.83), but was not significant after further adjustment for arterial stenosis or occlusion. CONCLUSIONS: Patients with a TIA but having no self-awareness of their symptoms might have higher risk of subsequent ischemic stroke rather than those with self-awareness, suggesting urgent management is needed even if patients have no self-awareness of symptoms.

Intravenous thrombolysis for patients with reverse magnetic resonance angiography and diffusion-weighted imaging mismatch: SAMURAI and NCVC rt-PA Registries.

BACKGROUND AND PURPOSE: The characteristics of reverse magnetic resonance angiography and diffusion-weighted imaging (MRA-DWI) mismatch (RMM), defined as a large DWI lesion in the absence of major artery occlusion (MAO), remain unknown, especially in patients treated with intravenous recombinant tissue plasminogen activator (rt-PA). METHODS: Patients with stroke in the middle cerebral artery territory were included. Early ischaemic changes (EIC) were assessed with the Alberta Stroke Program Early CT Score on DWI (DWI-ASPECTS). All patients were divided into four groups based on the presence of MAO and a DWI-ASPECTS cut-off value of <7. RMM was defined as DWI-ASPECTS <7 without MAO. Clinical characteristics, symptomatic intracerebral hemorrhage (sICH) and favorable functional outcome (modified Rankin Scale score 0-2) at 90 days were compared amongst the four groups. RESULTS: Of the 486 patients enrolled (167 women, median age 74 years, median initial National Institutes of Health Stroke Scale score 13), reverse MRA-DWI mismatch was observed in 24 (5%). Of the clinical characteristics, cardioembolism was the only factor that was independently associated with RMM [odds ratio (OR) 5.49, 95% confidence interval (CI) 1.25-24.1]. Multivariable analyses revealed that patients with RMM more commonly had sICH than those with DWI-ASPECTS ≥ 7 irrespective of the presence (OR 5.44, 95% CI 1.13-26.1) or absence (13.1, 2.07-83.3) of MAO, and they had a more favorable functional outcome than those with DWI-ASPECTS < 7 plus MAO (7.45, 2.39-23.2). CONCLUSION: RMM was observed in 5% of patients treated with rt-PA and associated with cardioembolism. Patients with RMM may benefit from thrombolysis compared with those with EIC with MAO, although increment in the rate of sICH is a concern.

Assessment of postischemic reperfusion and diamox activation test in stroke using 99mTc-ECD SPECT.

To evaluate the cerebral distribution of 99mTc-ethyl cysteinate dimer (99mTc-ECD) at blood flow levels beyond the normal range, we investigated postischemic reperfusion and acetazolamide (Diamox) activation test in stroke patients. The postischemic reperfusion was studied in 10 patients who showed a postischemic hyperperfusion area on other single photon emission computed tomography (SPECT) studies using N-isopropyl-rho-[123I]iodoamphetamine ([123I]IMP), 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO), or 133Xe. 99mTc-ECD SPECT demonstrated a hyperactive area in one case, an isoactive area in four, and a hypoactive area in five. Correlations with CT findings revealed hyperactive areas without any abnormality, isoactive areas with perifocal rim, perifocal edema, or diffuse cerebral edema, and hypoactive areas with an infarct core. The Diamox activation test was studied in eight other patients with atherothrombotic stroke, and a limitation in vasodilative capacity was classified into three grades: Gr. 0 (none to minimal), Gr. I (mild), and Gr. II (moderate). [123I]IMP SPECT showed Gr. II and limitation in all eight cases. However, 99mTc-ECD showed Gr. II in three cases and Gr. I in five, and 99mTc-HMPAO revealed Gr. II in two cases, Gr. I in three, and Gr. 0 in three. We suggest that a lack of retention of 99mTc-ECD in a postischemic reperfusion area indicates the severity of the initial brain damage. Although the limitation in vasodilative capacity under Diamox-activated conditions was underestimated using 99mTc-labeled CBF tracers as compared with [123I]IMP, a retention of 99mTc-ECD in the unaffected area with an increased CBF under Diamox activation could be relatively superior to 99mTc-HMPAO.

Intraarterial digital subtraction angiography for definitive diagnosis of intracranial aneurysms.

Comparisons between digital subtraction angiography and conventional angiography have frequently been made in the radiologic literature, and the high quality and several advantages of the former have been reported. In this study, 101 patients with intracranial aneurysms were examined only by intraarterial digital subtraction angiography; no conventional angiography was used. High-quality images were consistently obtained, facilitating an accurate and definitive diagnosis of intracranial aneurysm. Magnification radiography and stereography using intraarterial digital subtraction angiography were done to obtain a more precise diagnosis. Five small intracranial aneurysms with diameters of 1.0 to 2.0 mm could be detected. The procedure was considered to be as reliable and as safe as conventional angiography, used previously. Important advantages of intraarterial digital subtraction angiography include reduced procedural time and decreased contrast agent burden, factors that will ensure broader application of this procedure for definitive diagnosis of intracranial aneurysms as experience with the technique accumulates.

Quantification of regional cerebral blood flow and vascular reserve in childhood moyamoya disease using [123I]IMP-ARG method.

Both regional cerebral blood flow (rCBF) and regional vascular reserve (rVR) in ten childhood Moyamoya disease were quantified pre- and post-operatively by autoradiographic processing using single photon emission computed tomography (SPECT) and N-isopropyl-rho-iodoamphetamine (IMP) (IMP-ARG method) to estimate hemodynamic effectiveness of surgical revascularization. Before surgery, in two patients, rCBF was reduced in the whole territories and loss of rVR in the anterior circulation was observed; +4.3% in the anterior cerebral artery (ACA), -3.0% in the middle cerebral artery (MCA) and +17.5% in posterior cerebral artery (PCA) territories. After surgery, in eight patients without transient ischemic attack (TIA) episodes, rCBF at rest was maintained around subnormal level in the whole territories, and mean rVR was up to +11.9, +17.3 and +28.3% in ACA, MCA and PCA territories, respectively. However, rVR in the anterior circulation was significantly reduced in comparison with rVR in the posterior circulation. Quantification of both resting rCBF and rVR using IMP-ARG method could provide reliable information concerning on surgical indication and its effectiveness in childhood Moyamoya disease.

Putaminal hyperperfusion in dystonic posturing on subtracted SPECT: a case report.

Dystonic posturing (DP) is one of the most reliable lateralizing symptoms for mesial temporal lobe epilepsy, although the mechanism remains unclear. We demonstrated a hyperperfusion area in the right putamen on subtracted postictal SPECT by using the automatic registration technique in one patient with ictal DP of the left hand. The putamen may play a key role in DP, similar to other diseases with dystonia.

Early effects of gamma knife radiosurgery on brain metastases: assessment by 201TlCl SPECT and 99mTc-DTPA-human serum albumin SPECT.

Thallium-201 chloride (201TlCl) single photon emission computed tomography (SPECT) was used to determine tumor viability, and the early and delayed images of technetium-99m-diethylenetriaminepenta-acetic acid-human serum albumin (99mTc-HSA-D) SPECT were used to assess tumor vascularity and permeability, respectively, in 17 patients with 18 brain metastases. SPECT was performed before, 1 week after, and 1 month after radiosurgery. The ratios of 201Tl and 99mTc-HSA-D uptake in a tumor were expressed as a ratio to uptake in the corresponding normal contralateral areas (uptake index). Magnetic resonance imaging with gadolinium was used to determine tumor volume. 201Tl index decreased significantly 1 week (p < 0.05) and 1 month (p < 0.005) after radiosurgery. In contrast, 99mTc-HSA-D indices of early and delayed images obtained at 1 week after radiosurgery were not significantly different from the pretreatment values. However, both were significantly low (p < 0.05) 1 month after radiosurgery. No change in tumor volume was detected 1 week following radiosurgery, but there was a significant decrease (p < 0.005) after 1 month. The reduction in tumor viability that occurs before the appearance of evidence of tumor shrinkage represents the early effect of radiosurgery on brain metastases. Reduction in tumor size, vascularity, and permeability occur subsequently.

[Paradoxical embolism with Chiari network, subsequently being accompanied by probable incomplete infarction: a case report].

We presented a patient of paradoxical embolism with Chiari network, subsequently being accompanied by probable incomplete infarction. This 21-year-old man suffered from consciousness disorder, aphasia and right hemiparesis, and hospitalized in November 6, 1999. Magnetic resonance imaging showed mixed intensity on T1 and T2-weighted images in part of the areas of the left anterior and middle cerebral arteries. Cerebral angiography revealed the early venous fillings and the capillary blushs. These findings implicated stroke in young adult. Still more transcranial color-flow imaging showed high intensity transient signals with "Chirp" sounds on the left middle cerebral artery. Transesophageal echocardiography detected Chiari network. Chiari network was thought the course of cerebral infarction. Over again 123I-IMP single-photon emission CT findings revealed the marked reduction of his cerebral blood flow comprehensively in the left hemispherium. It was suggested that the recanalization after the paradoxical cerebral embolism had caused incomplete infarction.

[A case of clear cell meningioma originating from the cerebellar tentorium].

We report herein on a case of clear cell meningioma originating from the cerebellar tentorium, surgically treated by occipital transtentorial approach (OTT). A 67-year-old woman was admitted to our hospital in September, 1996, complaining of gait disturbance. MRI revealed an isointense mass on T1 and T2 WI, clearly enhanced with gadolinium in the right upper cerebellum originating from the tentorium. A left vertebral angiogram showed tumor stain from the right superior cerebellar artery. The tumor was subtotally removed by OTT on September 24, 1996. Gamma knife radiosurgery was performed for regrowing tumor 6 months after surgery. Histological examination revealed that the tumors were composed of sheets of clear, glycogen-rich cells and lobulated by thin connective tissues. There were no malignant findings, but some tumor cells had infiltrated into the cerebellar cortex. Immunohistochemistry showed that tumor cells were positive for EMA and vimentin, but negative for keratin. MIB-1 staining index was 7.02%. From these findings, this case was diagnosed as a typical clear cell meningioma originating from the cerebellar tentorium. From a review of the literature including our case, clear cell meningioma may be clinicopathologically malignant, so careful follow-up will be necessary.

[Three cases of infra-optic course of the anterior cerebral artery].

Three cases of rare anomalous cerebral artery originating from internal carotid at the level of ophthalmic artery to join the anterior cerebral artery were presented. Case 1. A 32-year-old woman was admitted following subarachnoid hemorrhages. Cerebral angiography disclosed the anterior communicating artery aneurysm and the anomalous vessel originating at rt. carotid siphon to join anterior cerebral artery. Case 2. A 37-year-old woman was admitted with rt. hemiparesis and aphasia. Cerebral angiography revealed the anomalous vessel originating at rt. carotid siphon to join contralateral anterior cerebral artery. Case 3. A 22-day-old male infant with enlarged head was admitted and cerebral angiography was performed. Anomalous vessel originating from internal carotid at the level of ophthalmic artery joined to the azygos anterior cerebral artery. There were only sixteen reported cases of this anomaly including our three cases. Seven aneurysms were associated in six cases, in which four were located in anterior communicating system. The fact that among the cases of this anomaly, ophthalmic artery used to not have normal stem but be fed from middle meningeal or middle cerebral artery suggested that the anomalous vessel had the common stem with ophthalmic artery at certain embryonic stage. These considerations led us to the conclusion that this anomalous vessel might originate from the remnant of anastomotic loop between primitive dorsal and ventral ophthalmic artery.

[Pituitary apoplexy with an unruptured carotid-ophthalmic aneurysm].

The association of pituitary adenoma and adjacent cerebral aneurysm is not uncommon and acute hemorrhage into a pituitary adenoma is also a well recognized condition. However, the simultaneous occurrence of pituitary apoplexy with intracranial aneurysm is very rare. Such a case demonstrates the diagnostic difficulty in distinguishing between pituitary apoplexy and rupture of an aneurysm. We reported a patient with subarachnoid hemorrhage in whom a hemorrhage into the pituitary adenoma and a carotid-ophthalmic aneurysm was proven, and discussed the differential diagnosis and treatment. A 41-year-old man, who developed sudden severe headache with nausea and vomiting, was admitted to our hospital. Examination disclosed a mildly stuporous man with bilateral defects of upper lateral visual fields and lumbar puncture revealed subarachnoid hemorrhage. Plain radiographs of the skull showed an enlarged and eroded sella turcica. Carotid angiography revealed a left carotid-ophthalmic aneurysm. A plain CT scan demonstrated an acute suprasellar hematoma. A transsphenoidal operation was performed and postoperative course was uneventful.

[A case of cerebral arteriovenous malformation revealed at repeated subcortical hematoma with initially normal angiogram].

An 18-year-old male admitted to our hospital suffered left temporal subcortical hemorrhage. No abnormality was demonstrated on carotid or vertebral angiography at that time. On the day following the onset, left frontotemporal craniotomy was performed and the subcortical hematoma was evacuated. No vascular malformation was found despite careful investigation. On 30th day after the onset, the repeat cerebral angiography was performed but failed to show any vascular abnormalities. After discharge he was in good health, and had had some follow up, CT were normal except for the hematoma cavity. Just two years after the first operation he suffered a second left temporal hemorrhage. Cerebral angiography was repeated and a temporal arteriovenous malformation (AVM) was found with feeding vessels from the M-1 and M-2 portion of the left middle cerebral artery and from the left anterior choroidal artery, and draining veins to vein of Rosenthal and the straight sinus. One month after the second hemorrhage, left frontotemporal craniotomy was performed and complete excision of the AVM was carried out. Only five cases of AVMs in patients with normal angiograms several years before have been reported previously in the literature. But there are no cases in which surgery has been performed. Differently to those cases, in this case it was investigated operatively whether there was a vascular abnormality at the first hemorrhage. We didn't think, however, that the AVM demonstrated at the second hemorrhage had developed spontaneously because there had been a hemorrhage of unknown origin previous to it. It was assumed that a small angiographically occult AVM connected to the hematoma cavity existed at the time of the first hemorrhage but it was too small to be found even during surgical procedure. Such an angiography occult AVM had been growing for two years, and its growth had probably been facilitated by the presence of the hematoma cavity left after the first operation.

[Measurement of energy expenditure in the acute stage of head injury (Part I)].

Oxygen consumption (VO2), carbon dioxide production (VCO2), resting metabolic expenditure (RME), RME of that expected for an uninjured resting person of equivalent age, sex, and body surface area (RME%), nitrogen balance, and protein calorie contribution (PCC) were measured in 8 patients with head injury. Metabolic measurements were carried out with the technique of indirect calorimetry from onsets to 14th day. Mean values of VO2 and VCO2 were 298 ml/min, 236 ml/min respectively on admission and those decreased gradually. Mean values of RME%, nitrogen balance, and PCC were 130.6%, -14.5 gm/day, and 17.3% respectively on admission. And those three values significantly decreased on 14th day in those 8 patients. From those facts, it was implied that hypermetabolism and hypercatabolism existed, and measurement of energy expenditure was indispensable to supply enough calorie maintaining body weight and immunocompetence in the acute stage of head injury.

[Effects of compton scatter in quantitative brain SPECT].

Effects of Compton scatter has been investigated for quantitative single-photon emission computed tomography. Using a technique proposed by Ichihara and Ogawa (triple-energy window method) as a gold standard, effects of correcting the scatter has been evaluated for 5 different phantom configurations, as well as a clinical cerebral blood flow study with use of 123I-IMP. Without the scatter correction but with a correction for attenuation, a conventional reconstruction provided a non-uniform distribution for uniform phantom configurations, and the quantitative pixel counts being highly dependent on size and shape of the objects. On the other hand, a uniform distribution and quantitative pixel counts that were independent of size or shape of the object were obtained by applying the scatter correction using a conventional attenuation correction technique with use of a theoretical mu value of 0.146 cm-1, thus suggesting importance of the scatter correction. Similar results were observed without the scatter correction, if an empirical value of mu of 0.07 cm-1 was used in the attenuation correction. However, this procedure was found to decrease the image contrast between the high count and low count regions. Significant underestimation of 20-30% was caused in cortical gray matter regions, and overestimation of 20% in the white matter regions. In practical clinical studies, magnitude of the error is still unknown, and is probably dependent on shape, size and radioactivity distribution of the object. A further systematic study is required in order to investigate significance of the scatter correction in real clinical studies.

[Assessment of vascularity and permeability in brain tumor using SPECT and 99mTc-DTPA-human serum albumin in relation to 201Tl SPECT].

Single photon emission computed tomography (SPECT) using technetium-99m-DTPA-human serum albumin (99mTc-HSA-D) and thallium-201 chloride (201Tl) was simultaneously performed on 25 patients with brain tumors; 10 with brain metastasis, 8 with astrocytoma (Gr. 3) and 7 with meningioma. The early image was obtained 10 minutes after 99mTc-HSA-D (740 MBq) injection, and the delayed image was taken 5 hours after the injection. HSA-D index, based on the ratio of 99mTc-HSA-D uptake in the tumor versus the cortical area, was calculated on each image, and compared with Tl index (tumor/contralateral cerebrum ratio). HSA-D delayed index was significantly greater than HSA-D early index in all tumor types (p < 0.05 by the Wilcoxon ranked sign test). Linear correlation between HSA-D early index and HSA-D delayed index was significant in astrocytoma (Gr. 3) (p < 0.01) and meningioma (p < 0.001), and a linear correlation between HSA-D delayed index and Tl index was significant in astrocytoma (Gr. 3) (p < 0.05). It is concluded that HSA-D early index and delayed index could reflect tumor vascularity and permeability, respectively, and provide supplementary information for Tl index.

[Phase 2 clinical study of 123I-iomazenil in various cerebral diseases: part 1--examination of injection dose and clinical indications].

A phase 2 study of 123I-Iomazenil (IMZ) was performed to evaluate its clinical usefulness in SPECT imaging of central-type benzodiazepine receptors (BZR). A total of 246 patients with various central nervous system disorders [82 with epilepsy, 94 with cerebrovascular disease (CVD), 47 with degenerative disorders, 14 with mental disorders relating to BZR and 9 with other diseases] were intravenously injected with 111-222 MBq of IMZ. Early and late images were obtained 15 min and 180 min after injection as the mid-scan time, respectively. In comparison with regional cerebral blood flow (rCBF) images, the uptake of IMZ in the late images, which reflect the regional distribution of BZR, was relatively preserved compared to the uptake of CBF tracers in most of the patients with CVD. In the area of hyperperfusion in the subacute phase of cerebral infarction, however, the defects of IMZ uptake were accompanied by increased uptake of the CBF tracers. On the other hand, late IMZ uptake in most of the patients with the other diseases was decreased more significantly than the uptake of the CBF tracers, suggesting that cortical neuronal damage is more prominent than rCBF in these diseases compared to the vascular perfusional state. No adverse reactions were recognized relating to the IMZ administration. These results suggest that IMZ may provide us with valuable information for assessing pathophysiological state in the brain, which are difficult to achieve with other imaging modalities.

[Phase 2 clinical study of 123I-iomazenil in various cerebral diseases: part 2--clinical evaluation of central-type benzodiazepine receptor imaging with 123I-iomazenil SPECT].

A phase 2 clinical study of 123I-iomazenil (IMZ) was performed to evaluate its clinical usefulness as central-type benzodiazepine receptor imaging agent in 81 cases with epilepsy, 82 cases with cerebrovascular diseases (CVD), 35 cases with degenerative disorders and 14 cases with mental disorders. In epilepsy, IMZ SPECT images for detection of epileptic foci showed relatively high specificity compared with EEG recording in not only interictal but also ictal state, in spite of the fact that IMZ SPECT images was performed during interictally. It was surmised that IMZ SPECT provides valuable clinical information for detection of epileptic foci which are hard to be diagnosed by EEG. The frequency of abnormal findings by IMZ late images was higher than that by interictal blood flow images and comparable to that by ictal blood flow images. In patients with CVD, different observations were obtained between IMZ late images and blood flow images; for example, in regions of hemodynamic cerebral ischemia, postischemic reperfusion and other pathological perfusion, IMZ late images seemed to reflect the degree of cortical neuronal loss. In patients with degenerative disorders, the binding potential (calculated by a simple quantitative method for IMZ) and other parameters correlated with the dementia score. While the number of examined cases with mental disorders was limited, the frequency of abnormal findings with IMZ imaging was higher than that with morphological imaging.

[A phase 3 clinical trial of 123I-iomazenil, a new central-type benzodiazepine receptor imaging agent (Part 1)--report on clinical usefulness in diagnosis of various brain diseases].

Iomazenil (IMZ) is a partial inverse agonist of central-type benzodiazepine receptors (BZR) which binds specifically to BZR with high affinity. The safety and clinical effectiveness of 123I-IMZ SPECT in the diagnosis of brain diseases were evaluated in 655 patients with various brain diseases, such as epilepsy, cerebrovascular diseases, degenerative diseases and mental disorders relating to BZR. This was a Phase 3 study conducted as a multicenter trial at 52 collaborating institutions. There was no significant adverse reactions in the clinical symptoms or abnormal laboratory test values. The investigators judged 123I-IMZ SPECT to be effective in 95% of 638 analyzed cases. The injected dose did not correlate with the image quality or the clinical effectiveness of 123I-IMZ SPECT, suggesting that these items depend largely on the characteristics of the apparatus used, the disease or pathology of the patients, rather than the dose. We conclude that 123I-IMZ imaging is safe and provides effective information based on BZR binding which is useful in the diagnosis of various brain diseases.

[A phase 3 clinical trial of 123I-iomazenil, a new central-type benzodiazepine receptor imaging agent (Part 2)--Report on clinical usefulness in diagnosis of degenerative neurological diseases and mental disorders].

Iomazenil (IMZ) is a partial inverse agonist of central-type benzodiazepine receptors (BZR) which binds specifically to BZR with high affinity. A multi-center Phase 3 clinical study was performed to evaluate the clinical usefulness of 123I-IMZ-SPECT in the diagnosis of brain disorders in 169 patients with degenerative neurological diseases and 37 patients with mental disorders such as neurotic, stress-related and somatoform disorders. In dementia, the decrease in activity in late images, obtained three hours after administration of 123I-IMZ, correlated negatively with the dementia score. In Parkinson's disease and spinocerebellar degeneration. 123I-IMZ showed a more profound decrease in uptake in late images than seen in the cerebral blood flow (CBF) images, and this decrease was in proportion to the duration and severity of the illness. In mental disorders, the ratio of the late to early image counts showed a negative correlation with Hamilton's anxiety scale in all regions in the brain cortices. In panic disorders, the ratio of the cerebral count to the cerebellar count in the late images correlated negatively with the severity of the attack in the frontal, temporal and parietal cortices. These results suggest that 123I-IMZ-SPECT enables us to evaluate the neuronal damage in degenerative diseases and the decrease in the BZR binding potential in mental disorders.

[A phase 3 clinical trial of 123I-iomazenil, a new central-type benzodiazepine receptor imaging agent (Part 3)--Report on clinical usefulness in epilepsy].

A Phase 3 clinical trial of 123I-Iomazenil (IMZ), a tracer which binds specifically to central-type benzodiazepine receptors (BZR), was performed, and the clinical usefulness of IMZ was evaluated in 121 patients with epilepsy (106 cases with partial epilepsy and 15 cases with generalized epilepsy). A regional abnormality in the BZR distribution was detected in late IMZ images in 20 of 24 cases without abnormal MRI and/or X-ray CT findings. Moreover, only 16 of these 20 cases showed abnormal findings in the cerebral blood flow (CBF) images. In partial epilepsy, abnormal regions in late IMZ images agreed or partially agreed with epileptic foci estimated from the clinical symptoms of epileptic seizures, interictal EEG, and MRI and/or X-ray CT findings in 76%, 70% and 96% of the cases detected. These regions also agreed or partially agreed with the estimated epileptic foci in 92% of the cases with foci estimated by combination of those three methods and in 72% of those estimated by ictal EEG. The agreement or partial agreement rates of late IMZ images with each of the other methods were higher than those of CBF images, although the differences were not significant. For surgically-proven epileptic foci without any abnormality in the CBF image, abnormal regions were detected in late IMZ images. These findings suggest that IMZ SPECT is a useful new tool for detecting epileptic foci based on the distribution of BZR in the brain.