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Background and Purpose. To investigate the clinical applicability and validity of [123I] iodobenzofuran (IBF) single-photon emission computed tomography (SPECT), the authors analyzed the changes in striatal dopamine D2 receptor binding among 7 patients with Parkinson's disease (PD), 6 patients with progressive supranuclear palsy (PSP) (Hoehn and Yahr stage II to IV), and 8 normal controls. Methods. SPECT data were acquired every 1 minute for 60 minutes postinjection of 167 MBq [123I] IBF. The binding potential (BP) of the striatum was evaluated by 2 methods: region-of-interest (ROI) analysis by the nonlinear least squares method using blood sampling and time-series brain radioactivities in normal controls and a voxel-by-voxel method based on a region model that provided parametric images of BP without blood sampling. Results. Statistical parametric mapping indicated that BP in the striatum of PSP patients was significantly lower than that of PD patients and normal controls (P

BACKGROUND AND PURPOSE: Although chronic-stage crossed cerebellar diaschisis (CCD) is reported to be associated with the neurologic state or clinical improvement after infarct, the prognostic value of early-stage CCD remains controversial. Our aim was to determine whether measurements of CCD in the acute and subacute stages obtained at single-photon emission CT (SPECT) facilitate the prediction of stroke outcome. METHODS: The pattern of cerebral blood flow changes after the occurrence of acute middle cerebral artery ischemia with severe cortical symptoms was examined by using technetium 99m-hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) SPECT. Fifteen patients (mean age, 73 years ± 8 [SD]) with unilateral ischemia were examined in the early subacute stage (10 days ± 5). In 11 patients, SPECT was performed in both the acute (16 hours ± 10) and subacute stages. From the total counts obtained from each cerebellar hemisphere, the asymmetry index (AI) was calculated as follows: [(value in unaffected hemisphere − value in affected hemisphere)/value in unaffected hemisphere] × 100. Clinical outcome (at 60 days) was assessed by means of the Scandinavian Stroke Scale (SSS) and Barthel Index (BI). RESULTS: AIs in the acute stage and clinical outcome (ie, SSS and BI scores) showed no significant correlation, but the severity of AI in the early subacute stage correlated significantly with both the final SSS (r = −0.69; P < .01) and BI scores (r = −0.82; P < .01). CONCLUSION: Cerebellar hypoperfusion detected at (99m)Tc-HMPAO SPECT in the early subacute stage in patients with supratentorial infarct indicates a worse clinical outcome.

The conventional protocol for whole-body positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) requires a total acquisition time of 40-60 min, which is inconvenient for many oncological patients owing to fatigue and discomfort. This study examined the feasibility of a short protocol for whole-body PET. A phantom containing six "hot" spheres of gradually increasing diameter (10-38 mm) was imaged using a dedicated PET scanner for 20, 40, 60, 80, 120 and 600 s at various count rates. Thirty-four patients with various neoplasms underwent whole-body emission scans for 1 min per bed position 1 h after intravenous injection of 370 MBq of FDG (short protocol). A standard simultaneous transmission-emission acquisition for 10 min per bed position was performed thereafter. The images were reconstructed using an iterative algorithm. At a count rate of 40 kcps, which is close to the average count rate obtained in a whole-body FDG PET study, the 60-s image visualised five spheres, of which the smallest was 13 mm in size. Despite the better image quality, lesion detection was not improved in images acquired for more than 60 s (80-600 s). Only three of the six spheres could be detected in images acquired for less than 60 s. In the patient study, the standard protocol visualised 120 tumour lesions, of which 93 (78%) could be detected using the short protocol. Among the non-visualised lesions, 22 (82%) wereor =1.5 cm in size and 17 (63%) were lymph nodes. It is concluded that the proposed short protocol for whole-body FDG PET has a reasonably high detection rate and may be suitable for patients who are unable to undergo scanning for a prolonged period. It may also be useful as a pre-scan guide before a standard whole-body acquisition.

We evaluated the short-term effects of a novel antiplatelet agent, 4-cyano-5,5-bis(methoxyphenyl)-4-pentenoic acid (E5510), using 111 In platelet scintigraphy (PSG) and B-mode ultrasonography (US). Fifteen patients with platelet deposition at either the carotid bifurcation or abdominal aorta on PSG were randomized into two groups: seven were followed without anti-thrombotic medication (Group A) and eight received E5510 (4 mg-day -1 ) (Group B). After 8 weeks, PSG and US were repeated in all patients. Platelet deposition was assessed visually and semi-quantitatively using a platelet accumulation index. Visual analysis showed that seven out of eight patients became negative for platelet deposition after treatment in Group B, while none changed in Group A. The platelet accumulation index of vessels with platelet deposition was significantly reduced after treatment in Group B (12.4 ± 3.9% vs 6.0 ± 7.1%, p < 0.01), while there was no significant change in the vessels without platelet deposition (2.9 ± 3.0% vs 2.9 ± 4.1%). In Group A, none of the vessels showed any change (8.1 ± 6.4% vs 8.9 ± 7.3%). However, there was no significant reduction of carotid plaque size in either group. Short-term E5510 therapy inhibited platelet deposition in active atherothrombotic lesions, and the combination of PSG and US was useful for evaluating the effectiveness of anti-thrombotic drugs in vivo.

Psychogenic amnesia is characterized by an inability to recall information already stored in the patient's memory. It is usually related to a stressful or traumatic event that cannot be explained by manifest brain damage. To examine the underlying functional disturbance of brain areas in this condition, we performed a positron emission tomography (PET) activation study on a psychogenic amnesic patient and on 12 normal control subjects. A task requiring explicit retrograde memory of faces was compared with a control task. To assess functional modifications associated with the processes of recovery, a second PET study was performed on the patient 12 months after onset. During the task, activation of the right anterior medial temporal region including the amygdala was increased in the psychogenic amnesic patient. Activation of the bilateral hippocampal regions increased only in the control subjects. During recovery, the right anterior medial temporal region became less active while the right hippocampal region became more active. Activation levels also differed in the anterior cingulate cortex, prefrontal cortex and some other cortical regions between control subjects and the patient. These findings suggest that the changes in these limbic and limbic-cortical functions are related to symptoms of the psychogenic amnesia.

The interaction of listening to words and watching sign language in short-term and long-term cochlear implant (CI) users who have learned sign language after becoming deaf was measured using PET. In short-term CI users the auditory cortex was inactive while in long-term CI users it was fully activated with the simultaneous presentation of auditory and visual input. The result suggests the possibility that the interference of rival modalities may be diminished with experience and the preference switchover from the visual input to the auditory input could be accomplished by means of the neural plasticity persisting in the mature human auditory cortex.

Positron emission tomography (PET) was performed in 10 normal volunteers to investigate regional cortical and subcortical activation induced by the lifting of an object repetitively using a precision grip between the index finger and thumb. Data were obtained for three object weights (4, 200 and 600 g) and a resting condition. Grip and lift forces on a similar object and the activity of selected muscles in the hand, arm and shoulder were also recorded in separate lifting trials. A comparison between all movement conditions and the resting condition revealed significant activation of the primary motor (M1), primary sensory (S1), dorso-caudal premotor (PM), caudal supplementary motor (SMA) and cingulate motor (CMA) cortices contralateral to the hand used. On the ipsilateral side, activation of the M1, caudal SMA and inferior parietal cortex (BA 40) was also found. In the subcortical areas, the bilateral hemispheres and right vermis of the cerebellum, left basal ganglia and thalamus were activated. Behavioral adaptation to a heavier object weight was revealed in a nearly proportional increase of both grip and lift forces, prolonged force application period and a higher level of hand and arm muscle activities. An increase in the rCBF associated with these changes was noted in several cortical and subcortical areas. However, consistent object weight-dependent activation was observed only in the M1/S1 contralateral to the hand used.

An 18-year-old man with tuberous sclerosis was studied with I-123 lomazenil SPECT and the findings were compared with those of MRI. In all cortical tubers detected with MRI, 1-123 iomazenil binding 180-191 minutes after intravenous administration was decreased significantly. This result indicates that the binding potential of 1-123 lomazenil is decreased in cortical tubers.

The effects of caloric vestibular stimulation on regional cerebral blood flow (rCBF) of the parietal and temporal cortex were examined in 10 healthy volunteers. The consecutive 99mTe-hexa-methyl-propyleneamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) method with region of interest analysis was used. Changes in rCBF induced by caloric stimulation with cold air (25°C) were evaluated in comparison with those induced by control stimulation with air at body temperature (37°C). Caloric stimulation with cold air induced vertigo in 4 subjects, dizziness in 2, and no sensation of self-motion in the remaining 4 subjects, whereas, control stimulation did not induce the sensation of self-motion in any subject. Although both parietal and temporal rCBF were slightly decreased during caloric stimulation, a correlation could be established between the magnitude of left-right differences in change of parietal rCBF and the degree of self-motion perception induced by cold-air caloric stimulation, as compared to control stimulation. Left-right differences in change of parietal rCBF in subjects with vertigo during caloric stimulation were significantly higher than those in subjects without any sensation of self-motion. In contrast, there was no correlation between the magnitude of left-right difference in change of parietal rCBF and maximum slow phase eye velocity induced by caloric stimulation. These findings suggest that the parietal lobe is involved in the perception of vertigo due to vestibular stimulation, but not in the vestibulo-ocular reflex.

Abstract We examined the relation between in vivo thrombogenicity and the morphology of carotid lesions to clarify the role of platelet deposition in carotid atherothrombosis. We evaluated 60 subjects (120 carotid bifurcations) who had at least one established risk factor for atherosclerosis by using indium 111 platelet scintigraphy and high-resolution B-mode ultrasonography. We evaluated platelet accumulation in the carotid arterial wall by means of a dual-tracer method that used In 111–labeled platelets and technetium 99m–labeled human serum albumin. The tracer accumulation was assessed both visually and semiquantitatively by using the platelet accumulation index, ie, the ratio of radioactivity of the amount of In 111–labeled platelets deposited on the vascular wall to the amount of radioactivity in labeled platelets circulating in the blood pool. The morphology of the carotid lesions was analyzed with B-mode ultrasonography in terms of the presence of ulceration, the maximum percent stenosis, the echogenicity of plaque, and the plaque score, which indicates the severity of systemic atherosclerosis. Platelet accumulation increased with increase in plaque score ( P P r =.28, P r =.42, P

We have studied 8 normal subjects, and 12 patients with idiopathic thrombocytopenic purpura whose platelet counts ranged from 9 x 10(9)/L to 40 x 10(9)/L. Autologous platelets labeled with 111Intropolone were used for evaluation of mean platelet survival, platelet turnover, platelet sequestration sites, and platelet production (turnover) to clearance (sum of platelet uptake in the liver and the spleen) ratio. Platelet survival correlated directly with platelet counts. There was no significant correlation between the platelet sequestration pattern and platelet count, survival, or turnover. Sum of platelet uptake in the liver and the spleen showed a significant inverse correlation with platelet survival. No significant correlation was found between platelet turnover and platelet count. There was a significant correlation between the platelet production to clearance index when all subjects were analyzed. The distribution of platelet turnover showed considerable individual variation; eight of twelve patients showed platelet turnover less than mean minus 2SD of the control value, but others showed normal range. We conclude that although platelet destruction mechanism in RES shows a primary role of thrombocytopenia, impaired rate of effective thrombopoiesis may also contribute to disease severity in ITP.

The upper regions of the brain's temporal lobe are important both for hearing and for comprehending spoken language. We have discovered that these regions can be activated by sign language in congenitally deaf subjects, even though the temporal lobe normally functions as an auditory area. This finding indicates that, in deaf people, the brain region usually reserved for hearing may be activated by other sensory modalities, providing striking evidence of neural plasticity.

Effects of hypocapnia on cerebral oxygen consumption (CMRO2) and blood flow (CBF) in cerebral ischemia were studied in 19 patients. The CMRO2 did not change significantly during hypocapnia within the whole group of patients, because 10 out of 19 cases showed a decrease (p less than 0.001) and other 9 showed an increase (p less than 0.01) of CMRO2 during hypocapnia. The first 10 showed higher resting CMRO2 (p less than 0.001) and arteriovenous differences of oxygen content (AVDO2; p less than 0.02) than the other 9. However, the resting CBF and CO2 reactivity to hypocapnia were not different between them, and clinical situations were also similar. A dissociation between flow and metabolism was suggested in the first 10 with rather preserved CMRO2, while reduced metabolic demands were suggested in the other 9. Different responses of CMRO2 to hypocapnia are expected in cerebral ischemia, i.e. in cases with rather preserved CMRO2 it decreases despite an AVDO2 increase, suggesting a capability of CMRO2 to respond to CBF reduction, while it increases in cases with more decreased CMRO2, as the AVDO2 increase exceeds the CBF reduction to maintain the decreased CMRO2 for a further CBF reduction. The vascular CO2 reactivity, therefore, might be maintained to be constant between these patients.

In ischemic cerebrovascular disease, it is not clear whether platelet function in vitro actually reflects the situation in vivo. Using indium-111 platelet scintigraphy as a method for detecting platelet activation in vivo, we tried to elucidate this problem. Twenty eight patients with chronic stage of ischemic cerebrovascular disease (CVD) and 17 control subjects were examined. Platelet scintigrams were positive in 9 of 28 patients in CVD, while all were negative in control. A comparison of the results obtained from qualitative platelet imaging and platelet aggregability was performed to evaluate whether threshold aggregation concentration (TAC) grade differed across the three groups (control, CVD patients without platelet deposition and CVD patients with platelet deposition). CVD patients with platelet deposition showed a higher TAC than those patients who did not show platelet deposition (P less than 0.05) or control subjects without platelet deposition (P less than 0.05). These results suggest that some patients in chronic stages of CVD may have active platelet deposition on carotid atheromatous lesions, and presence of platelet deposition in vivo could contribute to reduce platelet reactivity in peripheral blood.

The purpose of this study is to develop a useful gamma camera system for atraumatic rCBF measurement by the 133Xe intravenous injection (i.v.) method. A super high sensitivity slant hole (SHS-SL) collimator was designed for this purpose. The gamma camera used with this collimator was able to move close to the patient's head and obtain satisfactory count rates (130 kcpm-178 kcpm in a hemisphere) with a low dosage (10 mCi) of 133Xe. To validate this rCBF measurement system three studies were carried out: a comparative evaluation was performed against the flow values with the intracarotid 133Xe injection (i.c.) method, reproducibility of flow values was assessed from two serial i.v. measurements, and flow values were compared with clinical severity of the patients. The comparative study showed good correlation in the hemispheric and regional values between the two methods; r values 0.98 and 0.64-0.93 for gray matter flow and 0.96 and 0.78-0.93 for initial slope index. In the reproducibility study, the variation coefficients in the hemispheric and regional values between the two serial measurements were 5.0% and 7.3%-14.2% for gray mater flow, 5.2% and 7.9%-12.9% for initial slope index. The reproducibility in this study was as good as those with the i.c. method reported previously. The hemispheric flow values from our gamma camera system correlated well with the clinical severity of cerebrovascular disease. These results show that the gamma camera system with the SHS-SL collimator is useful for atraumatic rCBF measurement.