123I-IMP Single Photon Emission Computed Tomography Research Articles

Evaluation of cerebral perfusion in patients with neuropsychiatric systemic lupus erythematosus using 123I-IMP SPECT

In the course of systemic lupus erythematosus (SLE), central nervous system (CNS) complications occur at a high frequency. An accurate diagnosis of CNS lupus, differentiated from secondary CNS involvement, is difficult. CNS lupus is indicative of advancing primary disease and is treated by steroid pulse therapy or increased dosage of steroids. In contrast, if symptoms are caused by secondary CNS complications, it is possible to observe or treat these complications using symptomatic therapy. We examined whether quantitative cerebral blood flow (CBF) measured using cerebral perfusion single photon emission computed tomography (SPECT) can be used to differentiate CNS lupus from secondary CNS involvement. We divided 18 SLE patients with CNS symptoms into a CNS lupus group and a non-CNS lupus group, and then compared the mean cerebral blood flow (mCBF) of each group of patients. SPECT was performed with N-isopropyl-p-[123I] iodoamphetamine (IMP), with quantitation carried out by table look-up and autoradiographic methods. The mCBF of both groups was decreased; however, the mCBF of patients with CNS lupus was significantly lower than that of non-CNS lupus patients. Quantitative CBF may provide a useful tool to distinguish CNS lupus from non-CNS lupus.

Neuropsychiatric Background of Alcohol Hallucinosis: A SPECT Study

Back to table of contents Previous article Next article LETTERFull AccessNeuropsychiatric Background of Alcohol Hallucinosis: A SPECT StudyYurinosuke Kitabayashi M.D., Ph.D.Jin Narumoto M.D., Ph.D.Keisuke Shibata M.D.Hideki Ueda M.D., Ph.D.Kenji Fukui M.D., Ph.D.,Yurinosuke Kitabayashi M.D., Ph.D.Search for more papers by this authorJin Narumoto M.D., Ph.D.Search for more papers by this authorKeisuke Shibata M.D.Search for more papers by this authorHideki Ueda M.D., Ph.D.Search for more papers by this authorKenji Fukui M.D., Ph.D.Search for more papers by this author,Published Online:1 Jan 2007AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail SIR: Alcohol hallucinosis is a psychiatric condition characterized by auditory hallucinations, without consciousness disturbance, following drinking or cessation of alcohol. Although it is an important clinical issue in the management of alcohol dependence, the neuropsychiatric background of alcohol hallucinosis remains unknown. We report a case of alcohol hallucinosis in which we examined the neuropsychiatric background of the condition using N -isopropyl-p- 123 I iodoamphetamine ( 123 I-IMP) single photon emission computed tomography (SPECT). Case ReportThe patient was a 56-year-old Japanese junior high school graduate. He had a history of alcohol abuse of more than 30 years, with an average alcohol consumption of 200g/day (about 1.31 Japanese sake/day). He had experienced subacute auditory hallucinations and persecutional delusions for a month, during which time he intruded into his neighbor’s house and tried to set fire to the neighbor’s car. Finally, he was arrested by the police and admitted to our hospital. On admission, he was alert, and physical and neurological examinations revealed no abnormalities except for a mild finger tremor. Laboratory tests demonstrated only mild elevation of liver enzymes and the result of a magnetic resonance imaging (MRI) scan was intact. However, 123 I-IMP SPECT revealed a decreased regional cerebral blood flow (rCBF) in the frontal lobe, left basal ganglia, and left thalamus. A regimen of diazepam, 40mg/day, and haloperidol, 6mg/day, was initiated, and the hallucinations and delusions almost disappeared within a month. At this point, diazepam was tapered off and haloperidol was tapered to 3mg/day. After the disappearance of the hallucinations, the rCBF in the basal ganglia and thalamus normalized, but the rCBF decrease in the frontal lobe remained. In this case, rCBF decrease was observed in the frontal lobe, left basal ganglia, and left thalamus during the period of hallucinations, but the rCBF then normalized after recovery from the hallucinations, except in the frontal lobe.Comment Previous studies have demonstrated a toxic effect of alcohol on the frontal lobe, and hypofrontality is one of the characteristic findings of functional neuroimaging techniques in alcohol dependence. 1 On the other hand, functional abnormality of the frontal-subcortical circuit is well established in schizophrenia, the symptoms of which resemble alcohol hallucinosis. Sabri et al. 2 demonstrated a strong correlation between hallucinations and rCBF decrease in the cingulate, left thalamus, left frontal lobe, and left temporal lobe, and Soyka et al. 3 , 4 showed frontal and thalamic dysfunction in a case of alcohol hallucinosis but did not report the functional changes following treatment, which we assessed in this study. Collectively, the above findings suggest that the hypofrontality observed in this case probably reflects the effect of long-term alcohol dependence. Dysfunction of the left basal ganglia and left thalamus or coexistence of these abnormalities with frontal dysfunction could contribute to the development of alcohol hallucinosis, suggesting that alcohol hallucinosis may partially have a mutual neuropsychiatric background to that of schizophrenia.Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan

Pre-surgical identification of epileptogenic areas in temporal lobe epilepsy by 123I-iomazenil SPECT: A comparison with IMP SPECT and FDG PET

The aim of this study was to evaluate the usefulness of (123)I-iomazenil (IMZ) single photon emission computed tomography (SPECT) for the pre-surgical identification of epileptogenic areas in patients with temporal lobe epilepsy and to compare the results with those of (123)I-IMP SPECT and (18)Fluorodeoxyglucose positron emission tomography (FDG PET). We examined seven patients with medically refractory temporal lobe epilepsy (five men and two women; mean age, 28 years) with no remarkable findings on magnetic resonance imaging. Before surgery, IMZ SPECT, IMP SPECT and FDG PET were all performed in the interictal state. Then, visual assessment and region-of-interest (ROI) analysis were performed on each image. Final definitions of the epileptogenic areas were made by electrocorticography and histopathology. By IMZ SPECT, a decreased IMZ uptake in the ipsilateral temporal lobe was found in all patients, while a similar decrease in the contralateral temporal lobe was also found in one patient. In comparison to IMP SPECT, the extent of the abnormal area on IMZ SPECT was equal to that on IMP SPECT in one patient while it was more restricted to the epileptogenic area in five patients. In comparison to FDG PET, the extent of the abnormal area on IMZ SPECT was equal to that on FDG PET in three patients while it was more restricted in the epileptogenic area in four patients. In ROI analysis, decreases of IMZ, IMP and FDG uptake were observed in the epileptogenic area, although they were not statistically significant. IMZ SPECT was considered to be useful for pre-surgical determination of the epileptogenic areas in temporal lobe epilepsy with no remarkable MRI findings, and it was also found to be superior to IMP SPECT and FDG PET for this purpose.

Diastolic blood pressure influences cerebrovascular reactivity measured by means of123I-iodoamphetamine brain single photon emission computed tomography in medically treated patients with occlusive carotid or middle cerebral artery disease

Impaired cerebrovascular reactivity (CVR) to vasodilating agents is a predictor of the onset and prognosis of ischemic stroke. It is realized that the CVR improves or worsens when measured periodically during the clinical course in medically treated patients with occlusive cerebrovascular disease. In these patients, we investigated the possible relationship between the interval change in CVR and that in systemic blood pressure (BP). Forty-two patients (14 females and 28 males, mean age +/- SD: 65.3 +/- 8.8 years) with severe stenosis or occlusion of the common carotid, internal carotid, or middle cerebral arteries repeatedly underwent single photon emission computed tomography (SPECT) studies using 123I-iodoamphetamine to measure cerebral blood flow (CBF) distribution and CVR at a more-than-6-month interval (mean +/- SD: 18.5 +/- 8.8 months). The CVR was separately estimated in cerebral hemispheres ipsilateral and contralateral to the most severe vascular lesion as the % increase in CBF after acetazolamide loading to CBF at rest. Systemic BP was measured four times at enrollment and the follow-up SPECT studies during resting and acetazolamide loading. Average BP at each SPECT study was an average of BP measurements during resting and acetazolamide loading. Interval changes in CVR were correlated with those in average systolic BP, average diastolic BP, and average mean arterial BP. The interval changes in CVR were significantly correlated with those in average diastolic BP in the ipsilateral hemisphere (y = 0.71x + 1.43, r2 = 0.11, p < 0.05) and in the contralateral hemisphere (y = 0.88x - 0.46, r2 = 0.16, p < 0.05) but not with those in average systolic BP or average mean arterial BP. In medically treated patients with steno-occlusive carotid artery or middle cerebral artery lesions, the interval change in CVR to acetazolamide by means of 123I-IMP SPECT was influenced by the diastolic BP at the SPECT studies. Monitoring diastolic BP is important to evaluate interval change in CVR.

Central‐type Benzodiazepine Receptors and Epileptogenesis: Basic Mechanisms and Clinical Validity

Gamma-aminobutyric acid (GABA)-A/benzodiazepine receptors (BZRs) play an important inhibitory role in epileptogenesis. [123I]Iomazenil (123I-IMZ) is a specific ligand for central-type (or neuronal-type) BNRs and is available for single-photon emission computed tomography (SPECT) in brain disorders. We demonstrated alterations of central-type BZRs in human focal epilepsies and their experimental models. We examined interictal 123I-IMZ SPECT in patients with mesial temporal lobe epilepsy (MTLE; n = 19) with hippocampal sclerosis and neocortical epilepsy with focal cortical dysplasia (NE-CD; n = 18), and compared those with magnetic resonance imaging (MRI) and 123I-IMP SPECT (for regional cerebral blood flow). We also investigated in vitro autoradiography with (123)I-IMZ at various time courses in the intraamygdala kainate, amygdala kindling, and in-utero irradiation models. In MTLE patients, the epileptogenic hippocampus often showed decreases in both 123I-IMZ and 123I-IMP SPECT. Consistent with those, marked reduction of 125I-IMZ binding was observed in hippocampal CA1-3 regions of the kainate model, which clearly paralleled pyramidal neuronal loss. In contrast, 125I-IMZ binding was increased in the dentate gyrus at 1 month but returned to the normal level at 3-6 months, when frequent spontaneous seizures appeared. The amygdala-kindling model demonstrated similar increases in 125I-IMZ binding in the dentate gyrus without any changes in other brain regions. In NE-CD patients, the epileptogenic foci showed decreased 123I-IMZ binding with relatively normal 123I-IMP SPECT. 125I-IMZ binding also was decreased in the cerebral cortex, hippocampus (areas CA1, 2, and 4), and caudate/putamen of the in-utero irradiation model. These results indicate that central-type BZRs neuroimaging is useful for detection of epileptogenic foci, but their alterations differ between epilepsy subtypes and time-courses.

A case of neurosyphilis showing a marked improvement of clinical symptoms and cerebral blood flow on single photon emission computed tomography with quantitative penicillin treatment

A 31-year-old woman manifested significant emotional symptoms and personality change due to neurosyphilis; her clinical symptoms were improved with quantitative penicillin treatment. On admission, magnetic resonance imaging (MRI) showed no abnormal findings, while N-isopropyl- p-[ 123I] iodoamphetamine single photon emission computed tomography ( 123I-IMP SPECT) initially showed a remarkable increase in cerebral blood flow (CBF) in the cerebral cortex. This increase disappeared after improvement of the patient's clinical symptoms with treatment. It appears that the increase in CBF might have reflected an active inflammatory state of neurosyphilis and that its disappearance might therefore represent successful treatment with penicillin for neurosyphilis. Our case study suggests that single photon emission computed tomography (SPECT) is a useful method for evaluating an inflammatory state and for assessing the effect of therapy on neurosyphilis.

Regional cerebral blood flow in vascular depression assessed by 123I-IMP SPECT.

As the prevalence of white matter hyperintensities detected on T2 weighted MRI scans in patients with late-onset depression is higher than that in nondepressed patients, the concept of"vascular depression" (VDep) was introduced in 1997. However, the pathology of vascular depression has not been clarified. This study examined the differences in functional imaging between vascular and non-vascular depression (non-VDep). We utilized (123)I-IMP single photon emission computed tomography (SPECT) to compare regional cerebral blood flows (rCBF) between 9 patients with VDep (Krishnan criteria) and 11 age- and sex-matched patients with non-VDep in both depressed and remitted states. In both VDep and non-VDep patients, mean rCBF increased significantly as depression improved, partially aided by changes in left anterior temporal blood flow. In addition, compared to non-VDep patients, the left anterior frontal rCBF for VDep patients was significantly lower in both depressed and remitted states. Left anterior temporal rCBF therefore appears to represent a state marker that increases as symptoms associated with late-onset depression improve, regardless of vascular changes. Furthermore, in VDep patients, left anterior frontal rCBF was low in both states compared to non-VDep patients, and might not only represent a trait marker, but also correlated with the duration of disease and likelihood of recurrence and relapse.

Auditory Event‐Related Potentials (P300) and Regional Cerebral Blood Flow in Elderly Depressed Patients

Background:In order to evaluate the degree of impairment of cerebral function and the organic factors involved in elderly depressed patients, auditory event‐related potentials (ERP; P300) and N‐isopropyl‐p [123I] iodoamphetamine (123I‐IMP) single photon emission computed tomography (SPECT) were examined. Methods:Three groups of patients, the depression (D) group, consisting of 23 cases where the magnetic resonance imaging (MRI) showed no abnormalities, the depression with silent cerebral infarction (D/SCI) group, consisting of 28 cases with silent cerebral infarction, and the post‐stroke depression (D/PS) group, consisting of 19 cases at over six months after onset of cerebral infarction where no abnormalities in intellectual function were seen, but neurological symptoms such as hemiplegia were present, and 27 healthy individuals were investigated. All of the patients fulfilled the ICD‐10 diagnostic criteria for depressive episode, and disease onset occurred when the patients were over 55 years. The ERP (P300) was recorded using a tone discrimination task. Regional cerebral blood flow (rCBF) was measured by 123I‐IMP SPECT, and the relative rCBF of each region of interest was evaluated by comparison with the mean cerebellar rCBF. In addition, the mean cerebral blood flow (MCBF) in the cerebral cortex was assessed. Results:The D group included many cases in which the P300 peak latency was relatively short and the MCBF was stable, relative to the other two groups. In the D/PS group, there were many cases where the P300 peak latency was prolonged and the MCBF was reduced. In the D/SCI group, many differences in the results from both indicators existed among individual cases, and no fixed trend was identified. Conclusion: From the perspective of determining therapeutic tactics for elderly depressed patients and forecasting prognosis, it is important to review in detail, on an individual basis, components such as higher brain functions including cognitive functions, cerebral circulatory dynamics, and psychological/environmental factors. We believe that it is useful to evaluate a combination of factors when making such a review, including diagnostic imaging such as MRI, ERP (P300), and rCBF.

Spontaneous improvement in reduced vasodilatory capacity in major cerebral arterial occlusive disease.

Reduced vasodilatory capacity resulting from occlusive lesions of the major cerebral arteries may return to normal without surgical revascularisation. We aimed to determine prospectively the frequency and predictors of recovery of impaired haemodynamics as demonstrated by acetazolamide (ACZ) reactivity on single-photon emission computed tomography (SPECT). Vasoreactivity was measured by (123)I-IMP SPECT with an ACZ challenge, in 37 medically treated patients with unilateral occlusive disease of the internal carotid or middle cerebral artery at an interval of 1-2 years. Each ACZ challenge test was analysed semiquantitatively by calculating the degree of increase in cerebral blood flow (CBF) asymmetry after ACZ administration (DeltaAI). Vasodilatory capacity was abnormal initially in 20 patients (65 %); eight of whom (40 %) exhibited spontaneous normalisation on follow-up. Although the baseline characteristics did not differ significantly between patients with or without increase in reactivity, logistic regression analysis revealed that the initial DeltaAI (P < 0.05) and the type of vascular lesion (stenosis or occlusion) (P < 0.05) correlated significantly with a return towards normal of reduced ACZ reactivity. Spontaneous improvement of impaired vasodilatory capacity may not be a rare phenomenon. We found that mild reduction in the initial ACZ reactivity and a stenosis, but not complete occlusion, were independent factors contributing to normalisation of impaired cerebral haemodynamics.

Evaluation of peri-infarcted hypoperfusion with T2*-weighted dynamic MRI.

The purpose of this study was to evaluate cerebral perfusion with T2*-weighted dynamic MRI in the area around the infarcted core. We examined seven patients with subacute cerebral infarction. After bolus injection a gadopentetate dimeglumine, a series of gradient-echo images were recorded in a selected slice. From these images, concentration-time curves were created on a region-of-interest (ROI) basis around infarction for calculating relative regional cerebral blood volume (rrCBV). Brain perfusion single photon emission computed tomography (SPECT) study also was performed with intravenous injection of 123I-labeled N-isopropyl-p-iodoamphetamine (123I-IMP). All patients showed prolonged signal decrease in the area around the infarcted core. ROI analysis showed significantly increased rrCBV compared to the normal side (P < .01, paired t test). The 123I-IMP SPECT study showed that these areas had decreased cerebral blood flow. Theses findings suggest compensatory vascular dilatation due to decreased perfusion pressure. T2*-weighted dynamic MRI is a useful method for detecting compensatory vasodilatation of ischemic insult in the peri-infarcted area.

123I-IMP SPECT findings in mitochondrial encephalomyopathies

We performed N-isopropyl-[ 123I] p-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) in three patients with Leigh syndrome, two patients with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), and two siblings with progressive external ophthalmoplegia (PEO). The SPECT images were compared with the findings on magnetic resonance imaging (MRI) and computed tomography (CT). All Leigh syndrome patients showed low accumulation areas (LAA) bilaterally in the frontal lobes and the basal ganglia. The frontal lobe LAA was seen even in an area without abnormalities on CT/MRI. Each MELAS patient showed a focal LAA. SPECT could also detect an old stroke-like lesion that was no longer shown by CT/MRI. However, SPECT did not show LAA in the basal ganglia, which showed calcification on CT or abnormal signal intensity on MRI. MRI in the 2 PEO patients showed lesions bilaterally in the basal ganglia in one, and in the internal capsules in the other. SPECT showed LAA not only in corresponding areas, but also in the occipital lobes, where no lesions were revealed by MRI. Thus, 123I-IMP SPECT was more sensitive than CT/MRI for detecting stroke-like lesions in MELAS patients, although it did not detect small lesions in the basal ganglia. LAA in the frontal lobes and occipital lobes may be SPECT findings characteristic of Leigh syndrome and PEO, respectively.

Diagnostic accuracy of single photon emission CT in Alzheimer-type dementia

To determine the diagnostic accuracy of single photon emission computed tomography (SPECT) with 123I-IMP in Alzheimer-type dementia (ATD), we studied 46 ATD patients and 23 healthy controls. The patients fulfilled the NINCDS-ADRDA criteria for probable or definite ATD and were classified as having mild, moderate, and severe ATD by neuropsychological examinations. To assess regional cerebral blood flow, we performed qualitative SPECT image analysis without any knowledge of the subject's clinical classification. The image was regarded as abnormal if cerebral blood flow was reduced in the unilateral or bilateral temporoparietal association areas, with or without any reduction of flow in other brain regions. The diagnostic sensitivity (abnormal image/patient) of 123I-IMP SPECT in mild, moderate, and severe ATD was 67%, 86%, and 92%, respectively. The specificity (normal image/control) was 91%, because an abnormal image was found in only 2/23 healthy controls. Eight ATD patients without reduced temporoparietal perfusion showed normal perfusion or frontal hypoperfusion. These results suggest that 123I-IMP SPECT may provide an accurate and sensitive diagnostic marker for ATD. The detection of these characteristic marker for ATD. The detection of these characteristic abnormalities of cerebral perfusion could well be applied to the clinical diagnosis of ATD.

SPECT Studies in a Patient with Hemichorea: Case Report

The authors present single photon emission computed tomography (SPECT) images in a six-year-old boy with right hemichorea and motor aphasia. Neither computed tomography (CT) scanning nor magnetic resonance (MR) images showed any abnormality. 133Xe SPECT showed only a mild low-flow lesion in the territory of the left middle cerebral artery(MCA). However, 123I N- isopropyl-p-[123I] iodoanphetamine (IMP) SPECT showed a definite low-uptake lesion in the left MCA territory including the striatum and Broca's area. The authors stress the usefulness of 123I IMP SPECT in detecting mild ischemic le sions and discuss the mechanism of occurrence of hemichorea.

Investigation of Normal Pressure Hydrocephalus by &lt;SUP&gt;123&lt;/SUP&gt;I-IMP SPECT

We evaluated N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) as a method for identifying normal pressure hydrocephalic (NPH) patients eligible for shunting procedures. 123I-IMP SPECT scans were taken before and after cerebrospinal fluid (CSF) taps in NPH cases. Post-subarachnoid hemorrhagic (SAH) patients showed apparent frontal blood flow reduction but non-SAH cases did not. The frontal blood flow increased in comparison with the temporal flow after CSF tapping in SAH cases who benefited most from shunting. Cerebral blood flow study before and after CSF removal is a potential method for classifying NPH patients likely to benefit from the shunting operation.

Fluctuations of interictal brain imaging in repeated 123I-IMP SPECT scans in an epileptic patient

Single photon emission computed tomography (SPECT) brain scans with N-isopropyl-(iodine 123) p-iodoamphetamine (123I-IMP) were performed three times in interictal periods in a 35-year-old man with intractable frontal lobe epilepsy and normal X-ray CT findings. The first scan showed decreased 123I-IMP uptake in the right frontal lobe. This abnormal image was regarded as the primary focus of his epilepsy on the basis of its regional agreement with focal epileptic discharges on EEGs. In the second scan, he showed normal imaging, while the third scan showed the same abnormal image as before, in the right frontal lobe. The frequency of his clinical seizures was almost unchanged during the intervals between scans and further EEGs recorded soon after each scan showed almost no changes in the basic activities and frequency of the epileptic discharges. Such fluctuations in SPECT brain imaging suggest that the severity of functional inactivation underlying the focal hypoperfusion image as an epileptic focus may fluctuate considerably in the interictal state with no relation to the clinical features of epilepsy.

An assessment of the role of 123I-N-isopropyl-p-iodoamphetamine with single-photon emission computed tomography in the diagnosis of stroke and Alzheimer's disease.

The role of 123I-N-isopropyl-p-iodoamphetamine (123I-IMP), a new agent used in brain imaging with single-photon emission computed tomography (SPECT), has been assessed in the early diagnosis of acute infarctive stroke and Alzheimer's disease (AD). The diagnosis of these conditions in their early stages has remained problematic, principally due to limitations of existing technologies. To more formally assess this new technology, we estimated the sensitivity and specificity of 123I-IMP SPECT scanning in the diagnosis of stroke and AD. We based our assessment on a review of all published studies that reported on 123I-IMP SPECT scans and which included three or more patients. The results from three major studies indicate that 123I-IMP SPECT scanning has a higher sensitivity (92% to 100%) than computerized tomography (55% to 86%) in the early diagnosis of acute cerebral infarction. Preliminary findings from studies using 123I-IMP SPECT in the diagnosis of early AD are promising and show a sensitivity of at least 69%. Furthermore, 123I-IMP SPECT scanning clearly discriminates patients with advanced AD from normals: sensitivity has ranged from 50% to 100%, while specificity has ranged from 97% to 100%. Studies also suggest that it can discriminate AD patients from those with multi-infarct dementia. Our review indicates that 123I-IMP SPECT may have an important future role in the early diagnosis and management of patients with acute infarctive stroke and AD.

Local Cerebral Blood Flow Measurement by SPECT using &lt;SUP&gt;123&lt;/SUP&gt;I-IMP in Patients with Occlusive Cerebrovascular Disease

N-isopropyl-p-[123I] iodoamphetamine (123I-IMP) is a lipid-soluble radiopharmaceutical that penetrates the normal blood-brain barrier, and has a high first-pass extraction efficiency in the brain. When 123I-IMP is given intravenously, its activity in the brain is maintained for several hours and its distribution is postulated to be proportional to the local cerebral blood flow (ICBF). When combined with single photon emission computed tomography (SPECT), the regional activity of 123I-IMP can be quantified. Tomographic images of ICBF were obtained with both the 133Xe inhalation method and intravenous administration of 123I-IMP in patients with occlusive cerebrovascular diseases. Four patients with transient ischemic attacks showed normal X-ray CT but had decreased ICBF on SPECT in the areas corresponding to neurologic deficits. SPECT images showed low ICBF earlier and larger than X-ray CT abnormalities which appeared in patients with cerebral infarction. SPECT with the 133Xe inhalation method gives absolute ICBF values and has the advantage over 123I-IMP of short examination time. However, higher spatial resolution is obtained by 123I-IMP SPECT. X-ray CT will maintain a major role in the investigation of neurologic diseases when assessment of anatomic and morphologic changes is needed, and 1231-IMP SPECT perfusion images should have a complementary role in the menagement of neurologic diseases associated with alteration of ICBF.