Non-ketotic hyperglycaemic chorea: a SPECT study.

OBJECTIVE: To study regional blood flow of the striatum in non-ketotic hyperglycaemic choreic patients. METHODS: Brain SPECT was performed with intravenous injection of 20 mCi 99mTc hexamethylpropylene amineoxime in six non-ketotic hyperglycaemic choreic patients and 10 age matched patients with a similar level of hyperglycaemia without chorea as a control. The focal perfusion defects were analysed by visual interpretation and semiquantitative determination with reference to homolateral occipital blood flow. RESULTS: The measured blood flow of striatum on the contralateral side of chorea was significantly decreased. CONCLUSIONS: Hypometabolism of the striatum is seen not only in Huntington's disease, but also in non-ketotic hyperglycaemic chorea. Hypofunction of the striatum is a possible common pathogenesis in the development of contralateral chorea in different diseases. Furthermore, the sensitivity and reliability of SPECT is as good as PET in assessing choreic patients.     

Ictal 99mTc-HMPAO SPECT in alternating hemiplegia

99mTc-hexamethylpropylenamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) was performed in a patient with alternating hemiplegia during 2 episodes of the disease. The regional cerebral blood flow patterns correlated with the clinical manifestations during both episodes. Hyperperfusion of the contralateral hemisphere was suggested by asymmetric 99mTc-HMPAO uptake, whereas symmetric 123I-N-isopropyl-p-iodoamphetamine uptake was detected during the interictal period. The results suggested that alternating hemiplegia in infants represents an atypical manifestation of epilepsy, despite the lack of paroxysmal electroencephalographic abnormalities during the episodes. 99mTc-HMPAO SPECT appears to be a useful method for detecting transient regional cerebral blood flow alterations during paroxysmal events because the tracer is rapidly available for emergencies and retains a fixed distribution for 5-8 hours, sufficient time to allow for SPECT acquisition.     

Weakness of head turning in hemiplegia: a quantitative study.

The strength of head turning was measured in normal subjects and in patients with hemiplegia of vascular origin. In normals the strength of head turning to the two sides was not significantly different. In most patients with a cortical, capsular or high brainstem lesion the strength of head turning away from the side of the lesion was reduced. In patients with a medullary lesion the strength of head turning towards the side of the lesion was reduced. The significance of these findings is discussed in relation to the cortical control of the sternocleidomastoid muscle and other muscles involved in the movement of head turning.     

123I-iodoamphetamine SPECT brain imaging in alternating hemiplegia

Alternating hemiplegia of childhood is an unusual disorder characterized by early onset (occurring before 18 months of age); repeated attacks of hemiplegia involving both sides of the body; other paroxysmal phenomena, such as tonic stiffening, dystonic posturing, choreoathetoid movements, ocular motor abnormalities, and autonomic disturbances, in association with bouts of hemiplegia or occurring independently; and evidence of mental or neurologic deficits. A girl was examined because of left hemiplegia at the age of 16 months. The patient had begun exhibiting episodes of alternating hemiplegia at approximately 4 months of age. They consisted of tonic stiffening and dystonia of the right or left extremities, lasting from 30 min to several hours and followed by residual hemiparesis. They were invariably accompanied by ocular motor abnormalities. Magnetic resonance imaging, computed tomography, and angiography all were normal. Single proton emission computed tomography brain images during an acute episode of right hemiplegia demonstrated hypoperfusion of the left cerebral hemisphere. Following improvement of the hemiplegia, the patient was re-evaluated. The uptake of the radiotracer in the left hemisphere was increased. The scan did not demonstrate significant asymmetry in cerebral perfusion.     

Hypoglycaemic neuropathy: a case report

A 53 years old male, a known case of ankylosing spondylitis having recurrent attacks of hypoglycaemia, developed symmetrical distal sensorimotor neuropathy. The neuropathy was axonal with secondary demyelination. Evidence of vasculopathy was also noted on histopathology of the nerve. Serum C-peptide level was low, a feature reported with autoimmune hypoglycaemia with antireceptor antibodies. The patient showed spontaneous recovery.     

Secondary changes in cerebellar perfusion (diaschisis) in hemiplegia during childhood: SPECT study of 55 children

Diaschisis is a functional impairment at a site in the brain remote from the lesion causing it. An investigation of cerebellar diaschisis in childhood was undertaken to better understand the functional maturation of the corticopontocerebellar tract in developing brain. A retrospective study of cerebellar diaschisis in 55 hemiplegic children was conducted using singlephoton emission computed tomography (SPECT) with ¹²³I-IMP. Cerebellar diaschisis was evaluated by 2 authors. Crossed cerebellar diaschisis (CCD) was found in 6 of 55 patients. SPECT findings of patients who presented with CCD disclosed supratentorial hypoperfusion of varying degrees, from focally to the whole hemisphere; however, patients had frontal and/or parietal hypoperfusion in common. A second type of cerebellar diaschisis also was demonstrated. Cerebellar hypoperfusion ipsilateral to supratentorial lesions, ipsilateral cerebellar diaschisis (ICD), was observed in 10 of 55 patients. CCD occurred in the patients who suffered from brain injuries after 7 years, 5 months of age, while ICD manifested in patients whose brain injuries occurred before 3 years, 1 month of age. The production of remote effects, such as CCD and ICD, could be closely related to maturation of the corticopontocerebellar tract in the developing brain during childhood.     

Medial frontal cortex involvement in PTSD symptoms: a SPECT study.

The regional cerebral blood flow (rCBF) responses to a combat stress-related auditory stimulus was examined in Vietnam veterans diagnosed with posttraumatic stress disorder (PTSD). Based on prior data in healthy subjects, we hypothesized that the medial prefrontal cortex may be involved in the processing of stress responses. Twelve male veterans diagnosed with PTSD, 11 age-matched, combat-exposed subjects without PTSD, and 12 healthy control subjects were studied with single-photon emission tomography and the blood flow tracer [99mTc]-HMPAO. Subjects were studied twice, while listening to combat sounds or white noise. Significant increases in the blood flow to the medial prefrontal cortex were observed in PTSD patients, but not in the control groups, which correlated at trend levels with psychophysical measures of stress response. These data support the involvement of the medial prefrontal cortex in the pathophysiology of PTSD, possibly mediating some of its symptoms.     

Regional cerebral blood flow in childhood autism: a SPECT study.

OBJECTIVE: The authors investigated a possible cortical brain dysfunction associated with infantile autism. METHOD: They measured regional cerebral blood flow with single photon emission computed tomography (SPECT) and xenon-133 in 21 children with primary autism (according to DSM-III-R criteria). Five cortical brain areas including frontal, temporal, and sensory association cortices were examined in order to test the recent hypothesis of cerebral dysfunction in primary autism. Anatomical references for each subject were obtained with computerized tomography or magnetic resonance imaging and were used to delimit the regions of interest for SPECT analysis. RESULTS: When the results from the group with primary autism were compared with an age-matched group of nonautistic children with slight to moderate language disorders (N = 14), no cortical regional abnormalities were found. CONCLUSIONS: It appears that there is no regional cortical dysfunction in primary autism; however, in light of methodological limitations, one cannot exclude the possibility of more localized or subcortical brain dysfunctions in autism.     

Mirror therapy in children with hemiplegia: a pilot study

Mirror therapy, which provides the visual illusion of a functional paretic limb by using the mirror reflection of the non-paretic arm, is used in the rehabilitation of hemiparesis after stroke in adults. We tested the effectiveness and feasibility of mirror therapy in children with hemiplegia by performing a pilot crossover study in ten participants (aged 6-14 y; five males, five females; Manual Ability Classification System levels: one at level I, two at level II, four at level III, three at level IV) randomly assigned to 15 minutes of daily bimanual training with and without a mirror for 3 weeks. Assessments of maximal grasp and pinch strengths, and upper limb function measured by the Shriner's Hospital Upper Extremity Evaluation were performed at weeks 0 (baseline), 3, 6 (intervention), and 9 (wash-out). Testing of grasp strength behind the mirror improved performance by 15% (p=0.004). Training with the mirror significantly improved grasp strength (with mirror +20.4%, p=0.033; without +5.9%, p>0.1) and upper limb dynamic position (with mirror +4.6%, p=0.044; without +1.2%, p>0.1), while training without a mirror significantly improved pinch strength (with mirror +6.9%, p>0.1; without +21.9%, p=0.026). This preliminary study demonstrates the feasibility of mirror therapy in children with hemiplegia and that it may improve strength and dynamic function of the paretic arm.     

Thalamic ischemia in transient global amnesia: a SPECT study

We performed 99mTc-HMPAO SPECT in a patient during transient global amnesia and twice thereafter. SPECT during the attack showed a significant diminution of regional blood flow in the left thalamus and a less marked diminution in the right thalamus. Quantitative evaluation of global 99mTc-HMPAO uptake indicated a diffuse depression of cerebral blood flow. At follow-up to 40 days after the attack, global uptake and thalamic flow indices normalized, but there was a persistent reduction of left frontal flow values.     

Thyrotoxic autoimmune encephalopathy: a repeat positron emission tomography study

Thyroid related autoantibodies have been related to the development of encephalopathy, known as Hashimoto's encephalopathy. However, their relation with the encephalopathy occurring in patients with Graves' disease has not been well established. The case is reported of a 51 year old woman presenting with subacute progressive dementia with evidence of hyperthyroidism. She had Graves' disease associated with high titres of thyroid related autoantibodies. Her encephalopathy was not improved by antithyroid drugs, but promptly responded to corticosteroid treatment, and stabilised with a gradual reduction of thyroid related autoantibody titres. Brain positron emission tomography initially showed a diffuse and multifocal cerebral hypometabolism with subsequent normalisation on her clinical recovery, which was consistent with the acute and reversible cerebral inflammation probably mediated by autoimmune mechanisms.     

Crossed cerebellar diaschisis in acute ischemic stroke: a study with serial SPECT and MRI.

This study evaluated the relationship between crossed cerebellar diaschisis (CCD) and (1) lesion volume and location in the acute phase and 1 week after stroke onset and (2) clinical outcome. Twenty-two patients with cerebral ischemic stroke underwent single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) within 48 h and on day 8 from onset. Interhemispheric asymmetric indices (AI) on SPECT were calculated for medial, intermediate, and lateral zones of the cerebellum. Lesion volumes and locations were obtained from diffusion-weighted MRI. Neurological status and 3-month clinical outcome were evaluated. Within 48 h, lesion locations in the temporal association cortex and pyramidal tract of the corona radiata were independent determinants for the AI of the medial zone (R(2)=0.439). Lesion locations in the primary, premotor, and supplementary motor cortices, primary somatosensory cortex, and anterior part of the posterior limb of the internal capsule were determinants for the AI of the intermediate zone (R(2)=0.785). Lesions in the primary motor cortex, premotor, and supplementary motor cortices and in the genu of the internal capsule were determinants for the AI of the lateral zone (R(2)=0.746). On day 8, the associations were decreased. The AIs of the intermediate and lateral zones and lesion location in the parietal association cortex were independently associated with the 3-month clinical outcome (R(2)>0.555). Acute CCD is a result of functional deafference, while in the subacute phase, transneuronal degeneration might contribute to CCD. CCD in the intermediate and later zones is a better indicator than that in the medial zone.     

Context-dependent reasoning in a cognitive bias task Part II. SPECT activation study

A cognitive bias task (CBT) delineates two different cognitive selection mechanisms in the prefrontal cortex. To identify functional anatomy of context-dependent reasoning, we used technetium-99mhexamethyl- propyleneamine oxime (99mTc HM-PAO) single photon emission computed tomography (SPECT) and statistical parametric mapping. Twelve right-handed men 20-24 years old were instructed to look at a target card and then select the choice card (among two) that they preferred (modified CBT; mCBT). They also selected a choice card 2 weeks later without prior presentation of a target card (control task). In both tasks, 99mTc HM-PAO was injected intravenously about 15 s after initiation of the mCBT or control task. Brain images were obtained using a gamma camera and reconstructed by a UNIX-based workstation. Statistical analysis compared all activated images to control images. Results associated with P values of less than 0.01 (Z score > 2.36) were depicted on T1-weighted magnetic resonance images. All subjects preferred choices more similar to the target. SPECT activation occurred bilaterally in the dorsolateral prefrontal cortices and middle temporal gyri during performance of the CBT. Additionally, the left inferior prefrontal cortex and left fusiform gyrus showed significant activation compared with the control task. A neural network linking the temporal and prefrontal cortices prominently seen in the left hemisphere participates in context-dependent reasoning. Knowledge of such neural systems is essential for understanding prefrontal lobe function and dysfunction.     

Crossed cerebellar diaschisis in intracarotid sodium amytal procedures: a SPECT study

Eight patients with drug-resistant complex-partial seizures were subjected to left- and right-sided intracarotid sodium amytal (ISA) procedures during preoperative investigations for surgical treatment. Regional changes of cerebral and cerebellar blood flow during barbiturization were measured by [99mTc]-HMPAO-SPECT. Crossed cerebellar diaschisis (CCD) was observed in 13 out of 16 tests (81%) as well as ipsilateral cerebral hypoperfusion (87%). Thus CCD occurred more frequently in ISA procedures than in previously studied patients with cerebral infarctions and tumors. Since intracarotid injections of sodium amytal lead to hypoperfusion mainly in those areas of the brain that are supplied by the middle cerebral artery, functional suppression of these regions is supposed to be one of the main preconditions of CCD. Our findings suggest that CCD as demonstrated by the SPECT-technique is a common phenomenon in ISA procedures.     

Subclinical cerebral involvement in Behçet's disease: a SPECT study

Neurologic involvement has been reported in Behçet's disease (BD) with prevalence rates of 4–49%. Involvement of the central nervous system (CNS) usually follows systemic manifestations of BD by months to years, but as the initial future in only 5% of cases. The variance of the prevalence rates of neurologic involvement in BD raises the possibility of subclinical neurologic involvement. For the purpose of explaining the variance in the prevalence rates, 20 patients with BD, but without neurological symptoms and signs, were investigated by using cerebral single photon emission computed tomography (SPECT) which seems to be more convenient for BD than other scanners. A control group of patients with various diseases that were not expected to influence the cerebral blood flow was included. Brain magnetic resonance imaging (MRI) scans were performed in cases in which abnormal SPECT findings were obtained. Decreased and asymmetrical tracer uptakes were detected in 35% of patients with BD. MRI scans were normal in these patients. We concluded that functional imaging using SPECT may detect abnormalities at an initial stage prior to their progression to morphological damage detectable by MRI, and this imaging modality can be used even in cases which show no neurologic symptom to indicate the subclinical neurologic involvement.