99mTc-ethyl Cysteinate Dimer Research Articles

Probabilistic Anatomic Mapping of Cerebral Blood Flow Distribution of the Middle Cerebral Artery

Probabilistic atlases are more representative of the population than single brain atlases. They allow anatomic and functional labeling of the results of group studies in stereotactic space and, hence, the automated anatomic labeling of individual brain imaging data. In the current study, probabilistic maps of the blood flow distribution of the middle cerebral artery (MCA) were developed using the basal and MCA brain SPECT images. Twenty-nine patients (mean age +/- SD, 54.6 +/- 6.1 y) who previously received placement of a stent for MCA stenosis (right MCA stenosis, 15 patients; left MCA stenosis, 14 patients) were included in the current study. Of the 29 MCA SPECT images, 18 were analyzed for the final result because 11 MCA SPECT images revealed an uneven uptake distribution of (99m)Tc-ethylcysteinate dimer in the brain. MCA brain SPECT images were coregistered to basal brain SPECT images, and spatial normalization parameters used for basal brain SPECT images were reapplied to MCA brain SPECT for anatomic standardization. Pixel counts of the MCA brain SPECT images were then normalized, and the probabilistic map of cerebral perfusion distribution (perfusion probabilistic map) for each hemisphere was determined by averaging the spatial- and count-normalized MCA brain SPECT images. Population-based probabilistic maps representing the extent of MCA territory (extent probabilistic map) were also composed by averaging the binary images obtained by thresholding the spatially normalized MCA brain SPECT images. The blood supply from the MCA to the basal ganglia area was largest (probability, 0.6 approximately 0.8), followed by the insular cortex (probability, 0.3 approximately 0.5), and various cerebral cortical areas (probability, 0.2 approximately 0.4). The MCA reached to deep structures of the brain, including the internal capsule, caudate nucleus, putamen, globus pallidus, insular cortex, and thalamus with a high-extent probability. A population-based probabilistic map of MCA flow distribution was generated by using MCA brain SPECT images. This map could be a potential tool for the analysis of major cerebral artery distribution, especially the MCA. Furthermore, the probabilistic MCA atlas could be used to define the object delineation of the MCA territory, to quantify ischemic disease affecting the MCA, to predict prognosis, and to risk stratification of cerebrovascular diseases, especially affecting the MCA.

99mTc‐ethyl cysteinate dimer brain SPECT findings in early stage of dementia with Lewy bodies and Parkinson’s disease patients: a correlation with neuropsychological tests

We examined clinical presentations, neuropsychological findings, and perfusion patterns of (99m)Tc-ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) in patients with early stage dementia with Lewy bodies (DLB) (n = 17) and Parkinson's disease (PD) (n = 16), with age-matched healthy controls (n = 10). Seven paired regions of interest (ROIs) were drawn manually including inferior frontal, temporal, parietal, occipital, parieto-occipital junction, striatum and thalamus for semiquantitative measurement. Neuropsychological tests were applied for clinical correlation. The SPECT results showed significant hypoperfusion in DLB group in frontal, parietal, thalamus, temporal ROIs compared with controls (P < 0.01) whilst signals in temporal areas was significantly reduced compared with PD group (P < 0.05). Neuropsychological tests showed that DLB patients had deficits in mental manipulation, short-term memory, abstract thinking, drawing and semantic verbal fluencies (P < 0.05, compared with control). In addition, DLB group had lower scores than those with PD in mental manipulation, drawing and semantic verbal fluency (P < 0.05). Our study showed that even in early stages of DLB, neuropsychological and perfusion patterns were evident and may be different from PD group, despite they shared certain similarities both in neuropsychological and image findings compared with age-matched controls.

Sickle Cell Disease With Regional Silent Cerebral Infarction Detected by SPECT

An 18-year-old boy was admitted to the hospital for a right leg ulcer, which appeared 1 year ago. After physical and hematologic examinations, he was referred for neurologic and cardiologic examination because his hemoglobin analysis and hematologic findings were interpreted as being consistent with sickle cell anemia. Although he had no neurologic symptoms, MRI and Tc-99m ethyl cysteinate dimer cerebral perfusion single photon emission computer tomography were performed to rule out a silent cerebral infarction. Changes secondary to an infarct were seen in the region of the caudate nucleus.

Reduced Cerebral Blood Flow During Wakefulness In Obstructive Sleep Apnea-Hypopnea Syndrome

To investigate changes in regional cerebral blood flow (rCBF) in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). We compared the 99mTc-ethylcysteinate dimer (ECD) single photon emission computed tomography (SPECT) images of patients with OSAHS with those of age- and sex-matched healthy volunteers. University hospital. Twenty-seven patients with severe OSAHS and 27 healthy volunteers underwent 99mTc-ECD brain SPECT studies. For statistical parametric mapping analysis, all SPECT images were spatially normalized to the standard SPECT template and then smoothed using a 14-mm full-width at half-maximum Gaussian kernel. The Student t test was used for the statistical analysis. The mean age of patients and subjects was 44.3 years (range 31-58). All patients underwent overnight polysomnography. The mean apnea-hypopnea index of patients was 60.4 +/- 17.6 per hour (range 33 -104), indicating severe OSAHS. All patients snored heavily and had daytime sleepiness (mean Epworth Sleepiness Scale score, 10.7 +/- 3.7, range 6-12). Statistical parametric mapping analysis showed that rCBF in patients with OSAHS was significantly reduced in bilateral parahippocampal gyri and in the right lingual gyrus, as compared with that of healthy volunteers (P < 0.05 with false discovery rate correction). Moreover, apnea-hypopnea indexes of patients were negatively correlated with rCBF in the right pericentral gyrus and right cuneus at uncorrected P < 0.001. Our results show the altered rCBF pattern in bilateral parahippocampal gyri, right lingual gyrus, pericentral gyrus, and cuneus in patients with severe OSAHS. These findings may partly explain the deficit in memory, spatial learning, executive function, and attention, which are frequently found in patients with OSAHS.

Tc-99m ECD Neuro-SPECT and Diffusion Weighted MRI in the Detection of the Anatomical Extent of Subacute Stroke

We present a case of subacute middle cerebral artery infarct, which demonstrates restricted diffusion on MRI and reperfusion hyperemia in the posterior half of the lesion on angiography. Tc-99m ethyl cysteinate dimer (ECD) SPECT obtained shortly after the MRI failed to demonstrate perfusion defects in the regions demonstrating reperfusion hyperemia on angiography, underestimating the true size of the infarct. Crossed cerebellar diaschisis is, however, present. SPECT studies obtained over the following weeks demonstrated gradual enlargement of the lesion to approximate the MRI signal changes over a 19-day period. The case presented demonstrates retention of ECD in the infarcted brain. Several studies have demonstrated that Tc-99m ECD uptake is dependent on preserved brain tissue function because tracer retention requires enzymatic esterase activity, rather than the passive, nonenergy dependent trapping of Tc-99m hexamethylpropyleneamine oxime. Hence, infarcted areas undergoing reperfusion hyperemia are unlikely to demonstrate ECD uptake. This report illustrates that MRI diffusion weighted imaging may be more accurate in demonstrating the full extent of reperfused infarcts earlier than Tc-99m ECD SPECT. SPECT in this case failed to demonstrate reduced uptake in reperfused regions of the infarct. Also, crossed cerebellar diaschisis may serve as an early marker of extensive neuronal dysfunction.

Tc-99m ECD Early Dynamic Single Photon Emission Computed Tomography for Determination of Intra-Aneurysmal Dynamics Before and After Endovascular Treatment

The authors here describe a 44-year-old woman with a ruptured internal carotid-posterior communicating artery (IC-PC) aneurysm evaluated by Tc-99m ethyl cysteinate dimer (ECD) early dynamic single photon emission computed tomography (SPECT) before and after Guglielmi detachable coil (GDC) embolization. Our SPECT studies could be used to confirm the absence of aneurysmal blood flow after coiling.

Positive Tc-99m TRODAT Findings in Japanese Encephalitis

A 65-year-old female had high fever, headache, and myalgia for 7 days. She also had a resting tremor, shuffling gait, and bradykinesia. Brain MRI showed no specifically abnormal finding. Tc-99m ethyl cysteinate dimer (ECD) brain perfusion scan showed moderately decreased cerebral perfusion in bilateral frontal and bilateral temporal regions. Tc-99m [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo [3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato(3-)-N2,N2′,S2,S2′]oxo-[1R-(exo-exo)](TRODAT) is a potential agent for imaging dopamine transporter that measures dopamine terminal innervation of the striatum. The Tc-99m TRODAT scan showed significantly decreased uptake in bilateral striata. IgM capture enzyme-linked immunoassay of serum and CSF were performed and showed Japanese encephalitis.

Impairment of Decision-making Cognition in a Case of Frontotemporal Lobar Degeneration (FTLD) Presenting With Pathologic Gambling and Hoarding as the Initial Symptoms

The aim of this study was to use the Iowa Gambling Task (IGT) to examine decision-making cognition in a patient with mild frontal variant of frontotemporal dementia (fv-FTD). Although fv-FTD may present with bizarre and dramatic behavioral changes, traditional executive tasks are sometimes preserved in patients with mild fv-FTD. Some evidence suggests that tasks assessing decision-making cognition, such as the IGT, may be sensitive to detect cognitive dysfunction in patients with mild fv-FTD. Here, we report a patient with fv-FTD who presented with bizarre behavior including hoarding, pathologic gambling, and abnormal sexual behavior. A 54-year-old man who had been diagnosed as having fv-FTD was examined using a behavioral assessment, a wide range of neuropsychologic tasks, and the IGT. Brain magnetic resonance imaging and brain 99mTc-ethylcysteinate dimer single-photon emission computed tomography examinations were also performed. Although the patient's cognitive abilities were almost fully preserved for a number of traditional neuropsychologic tasks (memory, executive function), the IGT suggested that his decision-making cognition was impaired. The 99mTc-ethylcysteinate dimer single-photon emission computed tomography examination revealed hypometabolism in bilateral medial frontal and orbitofrontal regions of the cerebral cortex, and also in the cingulate gyri. Our findings suggest that the IGT may be a sensitive tool for assessing patients with mild fv-FTD before the development of severe dementia. We speculate that the deficit in decision-making cognition observed in the present case was associated with hypometabolism in the neural networks of the frontal lobe and involving both the bilateral medial frontal and orbitofrontal regions of the cerebral cortex.

Functional Imaging of Cataplexy During Status Cataplecticus

To identify the neural structures and pathways underlying cataplexy during status cataplecticus in a narcoleptic patient, using brain perfusion single photon emission computed tomography (SPECT). A 68-year-old woman with hypocretin-deficient narcolepsy-cataplexy suffered status cataplecticus after having stopped clomipramine. She underwent a 99mTc-ethylcysteinate dimer brain SPECT during an episode of cataplexy; this image was compared with her brain SPECT during an intervening asymptomatic period. Subtraction SPECT coregistered to magnetic resonance imaging (MRI)(SISCOM)-determined anatomic areas differentially perfused during cataplexy and basal wakefulness state. The areas hyperactivated during cataplexy corresponded on brain MRI with the cingular area, the left and right orbitofrontal cortex, the right temporal cortex, and the right putamen. No significant hypoperfused region was observed during the cataplectic episode. Cataplexy during status cataplecticus partially resembles normal rapid eye movement sleep (with high cingular, orbitofrontal, and putamen activity) but without the other imaging characteristics of this state (no hyperactivation of the pons, amygdale, or occipital cortex).

Episodic Diencephalic Hypoperfusion in Kleine-Levin Syndrome

A 22 year-old woman suffered from recurrent episodes of hypersomnia, apathy, and hyperphagia. The symptoms occurred 3 to 4 times per year, and each attack lasted 2 to 3 weeks. 99mTc-ethylcysteinate dimer brain single photon emission computed tomography (SPECT) was performed during symptomatic and asymptomatic periods. To localize brain regions with perfusion changes during symptomatic period, asymptomatic SPECT was subtracted from symptomatic SPECT. The subtracted SPECT showed significant hypoperfusion in the left hypothalamus, bilateral thalami, basal ganglia, bilateral medial and dorsolateral frontal regions, and left temporal lobe during the symptomatic period. These cerebral hypoperfusion areas support the diencephalic hypothesis and clinical symptoms of Kleine-Levin syndrome.

Brainstem hypoperfusion in severe symptomatic vasospasm following aneurysmal subarachnoid hemorrhage: role of basilar artery vasospasm

The hemodynamic effects of vertebrobasilar vasospasm are ill defined. The purpose of this study was to determine the effects of basilar artery (BA) vasospasm on brainstem (BS) perfusion. Forty-five patients with delayed ischemic neurological deficits (DIND) following aneurysmal subarachnoid hemorrhage (SAH) underwent cerebral angiography prior to decision-making concerning endovascular treatment. BA diameter was compared with baseline angiogram. Regional brainstem (BS) cerebral blood flow (CBF) was qualitatively estimated by (99m)Tc ethyl cysteinate dimer single photon emission computed tomography (ECD-SPECT). Delayed BS hypoperfusion was found in 22 (48.9%) of 45 patients and BA narrowing of more than 20% was found in 23 (51.1%). Seventeen of 23 (73.9%) patients with BA narrowing of more than 20% experienced BS hypoperfusion compared to 6 of 22 (27.3%) patients with minimal or no narrowing (p = 0.0072). Patients with severe and moderate BS hypoperfusion had higher degree of BA narrowing compared to patients with normal BS perfusion and mild BS hypoperfusion (p < 0.001). The three-month outcome of patients n-22) with BS hypoperfusion was significantly worse compared to patients (n-23) with unimpaired (p = 0.0377, odd ratio for poor outcome 4, 1.15-13.9 95% confidence interval). These findings suggest that the incidence of BA vasospasm in patients with severe symptomatic vasospasm is high and patients with significant BA vasospasm are at higher risk to experience BS ischemia. Further studies should be done to evaluate the effects of endovascular therapy on BS perfusion and the impact of BS ischemia on morbidity and mortality of patients with severe symptomatic vasospasm.

Brain perfusion effects of cholinesterase inhibitors in Parkinson’s disease with dementia

Several evidences suggest that cholinergic deficits may significantly contribute to dementia in Parkinson's disease (PDD) and acetylcholinesterase inhibitors (ChEIs) have been reported to improve cognitive symptoms in PDD, without worsening parkinsonism. Nineteen PDD patients underwent brain perfusion SPECT with (99m)Tc-ethyl cysteinate dimer after 6 months ChEIs treatment in order to evaluate the functional correlates of clinical improvement. A clear-cut cognitive improvement was reported in PDD patients with a significant improvement of ADAS-cog total score as well as of subscores exploring executive functions (p<0.01). MMSE total score did not significantly change after ChEIs but the subscore of attention significantly improved after therapy (p<0.01). No difference in motor performance as evaluated by UPDRS was reported. SPM analysis showed a significant increase of perfusion (p < 0.0001) in bilateral cingulate, and frontal regions after ChEIs. Our data confirm the efficacy of ChEIs in the treatment of dementia associated with PD mainly on attention and executive functions, and the functional findings indicate that this cognitive improvement could be associated with a sort of pharmacological frontal "re-afferentation".

Tc-99m ECD SPECT and FDG PET in Partial Status Epilepticus Resulting From Cerebral Sparganosis

Sparganosis is a rare intracranial parasitic disease caused by the infestation of a plerocercoid tapeworm larva of Spirometra mansoni. According to previous studies of cerebral sparganosis, common clinical features are seizure, hemiparesis, and chronic headache. We report a case of cerebral sparganosis in which the patient presented with a first attack of sustained unilateral jerky involuntary movements that concluded as a partial status epilepsy based on the ictal and interictal brain Tc-99m ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) and interictal FGD positron emission tomography (PET) studies.

Dynamic perfusion computerized tomography in cerebral vasospasm following aneurysmal subarachnoid hemorrhage: a comparison with technetium-99m–labeled ethyl cysteinate dimer–single-photon emission computerized tomography

The aim of this study was to correlate cerebral blood flow (CBF) and mean transient time (MTT) measured on dynamic perfusion computerized tomography (CT) with CBF using (99m)Tc ethyl cysteinate dimer-single-photon emission computerized tomography (SPECT) in patients with cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH). Thirty-five patients with vasospasm following aneurysmal SAH (12 men and 23 women with a mean age of 49.3 +/- 10.1 years) underwent imaging studies; thus, 35 perfusion CT scans and 35 SPECT images were available for comparison. The CBF and MTT values in 12 different brain regions were defined relative to the interhemispheric occipital cortex values using perfusion CT scans and were compared with qualitative relative (rel)CBF estimated on SPECT images. In brain regions with normal, mild (relCBF 71-85%), moderate (relCBF 50-70%), and severe (relCBF < 50%) hypoperfusion on SPECT, the mean relCBF values measured on perfusion CT were 1.01 +/- 0.08, 0.82 +/- 0.22, 0.6 +/- 0.15, and 0.32 +/- 0.08, respectively (p < 0.0001); the mean relMTT values were 1.04 +/- 0.14, 1.4 +/- 0.31, 2.16 +/- 0.46, and 3.3 +/- 0.54, respectively (p < 0.0001). All but one brain region (30 regions) with severe hypoperfusion on SPECT images demonstrated relCBF values less than 0.6 and relMTT values greater than 2.5 on perfusion CT scans. Relative CBF and MTT values on perfusion CT showed a high concordance rate with estimated relCBF on SPECT in patients with vasospasm following aneurysmal SAH. Given its logistical advantages, perfusion CT may be a valuable method of assessing perfusion abnormality in the acute setting of vasospasm and in patients with an unstable condition following aneurysmal SAH.

Acupuncture-induced cerebral blood flow responses in dystonia

The effect of acupuncture (ACP) on regional cerebral blood flow (rCBF) is unclear. Single-photon emission computed tomography studies on three patients with dystonia were performed before and after ACP treatment to test the contention that ACP affects rCBF. Pre-ACP and post-ACP CBF study were performed on the same day; 99mTc ethyl cysteinate dimer was injected for each study. rCBF images were analyzed using a three-dimensional stereotaxic ROI template (3DSRT) to objectively measure rCBF. We evaluated rCBF bilaterally in five segments related to the pathophysiology of dystonia (1, superior frontal; 2, middle and inferior frontal; 3, primary sensorimotor; 4, lenticular nucleus; and 5, thalamus). More than 10% left-right asymmetry in rCBF over three continuous slices was defined as significant laterality. Post-ACP rCBF and laterality were evaluated with the pre-ACP rCBF study acting as a control in each subject. The clinical effect of ACP was remarkable in all patients and rCBF increased in most segments. Pre-ACP rCBF exhibited significant laterality in eight segments of the three patients. Laterality reversed in seven of these segments and resolved in the remaining segment after ACP. Pre-ACP rCBF laterality was not preserved in any segment after ACP. The remaining five segments exhibited laterality only after ACP. In total, after ACP, 13 of 15 segments demonstrated a change in CBF that was greater unilaterally. ACP results in an increase in CBF that is greater unilaterally. We think that unilateral change in CBF may be correlated with the action of ACP on the central nervous system in patients with dystonia.

Balloon Test Occlusion with Perfusion CT Imaging Utilizing Intraarterial Contrast Injection

Balloon Test Occlusion (BTO) is performed to evaluate the collateral flow when a permanent therapeutic occlusion of unilateral carotid artery is planned. BTO with neurological evaluation alone, however, has a rather high false negative rate. In order to improve the sensitivity, several adjunctive procedures such as induced hypotension or cerebral blood flow (CBF) measurement with various modalities have been combined. Perfusion CT (PCT) is another imaging modality that is mainly used for the diagnosis of acute stroke. In this study, we evaluate the efficacy and the safety of BTO combined with PCT in the same procedure utilizing intraarterial contrast injection from the catheter. Seven patients underwent BTO with PCT in our institution. All the procedures were performed in the angio/CT combination suite. BTO was performed in the usual fashion and when the patient passed the 30 minutes' BTO clinically, PCT was performed subsequently. Contrast material was injected from a Pig Tail catheter placed in the ascending aorta. The obtained data were transferred to a workstation and perfusion maps of CBF, cerebral blood volume (CBV), and time to peak (TTP) were generated using software. In three patients, single photon emission CT (SPECT) was also obtained with administering 99 mTc-ethyl cysteinate dimer (99 mTc-ECD) intravenously during BTO. Although all the patients had passed the BTO clinically, the CBF maps of three patients revealed significant decrease in the occluded hemisphere. There was no procedure-related morbidity. PCT using intraarterial contrast injection during BTO was performed successfully and safely. Intraarterial injection allowed us to obtain excellent time-attenuation curves by utilizing less contrast material and less radiation doze.

Prognostic value of brain perfusion single-photon emission computed tomography (SPECT) for language recovery in patients with aphasia

To determine the prognostic value of brain perfusion single-photon emission computed tomography (SPECT) in patients with aphasia after a stroke. Brain perfusion SPECT with 99mTc-ethyl cysteinate dimer (99mTc-ECD) was used in 16 right-handed patients with aphasia after a left-sided cerebrovascular accident (CVA) in the early chronic period after the onset of CVA. The region of interest (ROI) method was used to calculate the relative regional cerebral blood flow (rCBF) in each cerebral lobe, the thalamus, the putamen and the cerebellum as ratios to the count in the left cerebellar hemisphere. The Standard Language Test of Aphasia (SLTA) was performed twice, once at the same time as SPECT, a mean of 2.3 months after CVA onset (early SLTA), and again a mean of 17.0 months after CVA onset (late SLTA). In addition to the overall language function score, scores for taking dictation (Dictation), oral reading (Speaking) and comprehension (Comprehension) were calculated, and the correlations with each of the rCBF values were evaluated. Left temporal CBF correlated with the late Dictation score; bilateral frontal, bilateral temporal and right parietal CBF correlated with the late Speaking score; and right frontal, left temporal and left occipital CBF correlated with the late Comprehension score. Brain perfusion SPECT in the early chronic stage was shown to be useful for predicting recovery from aphasia, recovery of oral reading, ability to take dictation and comprehension.

Cerebral perfusion abnormality in narcolepsy with cataplexy

To investigate abnormal cerebral perfusion in narcoleptics with cataplexy, 25 narcoleptics with cataplexy and 25 normal controls were enrolled in this study. Cerebral perfusion was measured by brain single photon emission computed tomography (SPECT) using 99mTc-ethylcysteinate dimer. Patients and normal controls had not received any medication prior to the SPECT scan. Differences in cerebral perfusion between narcoleptics and normal controls were subjected to statistical parametric mapping (SPM) analysis. Overnight polysomnography and multiple sleep latency test (MSLT) were performed in all patients. Brain SPECT was carried out on all patients and normal controls during the waking state. Clinical symptoms and MSLT results of all patients are in accord with the International Classification of Sleep Disorders criteria for narcolepsy. MSLT showed a short mean sleep latency (1.69 ± 1.0 min) and 2–5 sleep onset REM periods in individual patient. SPM analysis of brain SPECT showed hypoperfusion of the bilateral anterior hypothalami, caudate nuclei, and pulvinar nuclei of thalami, parts of the dorsolateral/ventromedial prefrontal cortices, parahippocampal gyri, and cingulate gyri in narcoleptics [ P < 0.05 by Student's t test with false discovery rate (FDR) correction]. Significant hypoperfusion in the white matter of frontal and parietal lobes was also noted in narcoleptics. This study shows reduced cerebral perfusion in subcortical structures and cortical areas in narcoleptics. The distribution of abnormal cerebral perfusion is concordant with the pathway of the cerebral hypocretin system and may explain the characteristic features of narcolepsy, i.e., cataplexy, emotional lability, and attention deficit.

Cerebral Accumulation of TC-99M Ethyl Cysteinate Dimer (ECD) in Severe, Transient Hypothyroidism

Thyroid dysfunction is a well-known contributor to psychiatric morbidity. To investigate the mechanism(s) by which thyroid hormone availability affects cerebral activity, a group of thyroidectomized individuals were studied at two points in time: when markedly hypothyroid in preparation for a thyroid cancer metastatic survey and when clinically and/or biochemically euthyroid. The analysis consisted of single photon emission computed tomography (SPECT) using a lipophilic radiopharmaceutical, technetium-99m (Tc-99m) ethyl cysteinate dimer (ECD), and measurement of mood, anxiety, and psychomotor function, at both points in time. Both increases and decreases in regional cerebral radiotracer activity were found in the hypothyroid condition relative to the euthyroid condition, and the neuropsychological assessment demonstrated significantly greater depression, anxiety, and psychomotor slowing during the hypothyroid state. Increased radiotracer activity was seen in frontal and temporal regions, posterior cingulate gyrus, thalamus, and putamen. Decreased activity was seen in the occipital cortex, and the pre- and postcentral gyri. This distribution pattern is partially consistent with findings in persons with depression and anxiety unrelated to thyroid disease, supporting the link between the symptoms observed in our subjects and their marked hypothyroidism. Finally, these results support the need to consider the effect of the thyroid state on cellular mechanisms of uptake and retention of cerebral blood flow radiopharmaceuticals when studying 'noneuthyroid' individuals.

Perfusion abnormality of the caudate nucleus in patients with paroxysmal kinesigenic choreoathetosis

Previous cerebral blood flow and glucose metabolism studies suggest that the basal ganglia or thalamus is involved in the pathogenesis of paroxysmal kinesigenic choreoathetosis (PKC). However, the underlying cerebral abnormalities in idiopathic PKC have not been elucidated. To localise cerebral perfusion abnormalities in PKC, we performed interictal brain perfusion 99mTc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in PKC patients and in normal controls. Sixteen patients with idiopathic PKC and 18 age- and sex-matched normal controls were included. The patients were de novo diagnosed as having PKC, or had not taken medication for at least 3 months; none of them had structural abnormalities on MRI. Patients had a history of PKC attacks of a duration not exceeding 5 min and starting either on one side or on both sides of the body. These attacks were always induced by a sudden initiation of voluntary movement. PKC attacks were recorded in a hospital after being induced by neurology staff in 13 of the 16 patients. Interictal brain perfusion 99mTc-ECD SPECT was performed in all 16 patients and 18 normal controls. Differences between the cerebral perfusion in the PKC group and the normal control group were tested by statistical parametric mapping. Student's t test was used for inter-group comparisons. Compared with normal controls, patients with idiopathic PKC showed interictal hypoperfusion in the posterior regions of the bilateral caudate nuclei (false discovery rate-corrected P<0.001 with a small volume correction). This study showed that cerebral perfusion abnormality of bilateral caudate nuclei is present in idiopathic PKC.