Palinopsia and perilesional hyperperfusion following subcortical hemorrhage

We report a patient who exhibited transient palinopsia and visual hallucinations. Disturbances initially included an auditory component and increasingly were localized to the left visual field. These events occurred during recovery from a right subcortical hematoma with left homonymous hemianopia. Single-photon emission computed tomography (SPECT) demonstrated extensive perilesional hyperperfusion involving parts of the right parietal, temporal, and occipital cortex. Perilesional hyperperfusion disappeared as the visual abnormalities diminished. We believe that excitatory neuronal activation in perilesional cortex during recovery contributed importantly to the transient abnormal perceptions.     

The usefulness of subtraction ictal SPECT coregistered to MRI in single- and dual-headed SPECT cameras in partial epilepsy

PURPOSE: To prove the clinical usefulness of SISCOM and compare SISCOM images derived from single- and dual-headed single-photon computed tomography (SPECT) cameras for localization of partial epileptic seizures. METHODS: We retrospectively studied 38 partial epilepsy patients, using subtraction SPECT coregistered to magnetic resonance imaging (MRI; SISCOM). SPECT imaging of the first 15 patients was performed by single-headed camera, and the next 23 patients by dual-headed camera. Side-by-side ictal-interictal SPECT evaluation and SISCOM images were blindly reviewed and classified as either localizing to one of 16 sites or nonlocalizing. A third reviewer evaluated cases of disagreement between primary reviewers. Results were compared with seizure localization by any of the following three traditional techniques: surgical outcome, invasive, and noninvasive video-EEG monitoring. The results from the single- and dual-headed SPECT cameras were compared. RESULTS: Reviewers localized areas of hyperperfusion with SISCOM images more often than with side-by-side SPECT evaluation (71.0 vs. 47.4%; p = 0.01). When we compared results of SPECT evaluation with traditional techniques, SISCOM showed greater concordance than side-by-side SPECT evaluation (60.53 vs. 36.84%; p = 0.006). There were no differences in localization between images derived from single- and dual-headed cameras. Concordance of seizure localization, compared with traditional techniques, also was not different between these groups [kappa = 0.38, 95% confidence interval (CI), 0.18-0.58] vs. kappa = 0.63, 95% CI (0.45-0.81)]. CONCLUSIONS: SISCOM is a worthwhile technique for preoperative evaluation in partial epilepsy patients and improves the sensitivity and specificity of seizure localization of SPECT images derived from both single- and dual-headed SPECT cameras.     

抗癫痫药物长期控制特发性癫痫异常灌注灶的修复

Epileptic seizure control and the disappearance of epileptiform discharge are not indicative of the absence of abnormal perfusion foci.Perfusion abnormalities are a major cause of epileptic discharge,and the existence of abnormal perfusion foci implies possible relapse.Very little is known about perfusion abnormality repair in epilepsy.The present study selected 43 cases of idiopathic epilepsy under antiepileptic drug control for an average of 24 months.Comparisons between interictal single-photon emission CT(SPECT)images and long-term electroencephalogram(EEG)pre-and post-treatment showed that cases of normal SPECT increased by 48%(12/25)following treatment,with a total number of 15 reduced foci(36%,15/41).Perfusion foci,i.e.,region of interest,were altered following treatment.These changes included:normal to abnormal in 3 cases(7%,3/43;2 hyperperfusion and 1 hypoperfusion);abnormal to normal in 14 cases(32%,14/43;10 pre-treatment hypoperfusion and 4 hyperperfusion);abnormal to abnormal in 7 cases(16%,7/43;hyperperfusion to hypoperfusion in 5 cases,hypoperfusion to hyperperfusion in 2 cases).Long-term EEG revealed in an increase in the number of normal cases by 20(40%,20/39),and there were 25 fewer cases with epileptiform discharges(66%,25/38).These findings demonstrate that long-term control of anti-epileptic drugs partially repaired cerebral perfusion abnormalities and reduced epileptiform discharges in idiopathic epilepsy.     

High-Resolution Brain SPECT Imaging in ADHD

Children and adolescents with ADHD were evaluated with high-resolution brain SPECT imaging to determine if there were similarities between reported PET and QEEG findings. Fifty-four children and adolescents with ADHD by DSM-III-R and Conners Rating Scale criteria were evaluated. A non-ADHD control group was also studied with SPECT. Two brain SPECT studies were done on each group, a resting study and an intellectual stress study done while participants were doing a concentration task. Sixty-five percent of the ADHD group revealed decreased perfusion in the prefrontal cortex with intellectual stress, compared to only 5% of the control group. These are findings consistent with PET and QEEG findings. Of the ADHD group who did not show decreased perfusion, two-thirds had markedly decreased activity in the prefrontal cortices at rest.     

SPECT findings during postictal psychoses: predominance of relative increase of perfusion in right temporal lobe

To identify brain regions activated during episodes of postictal psychoses (PIP), we investigated single-photon emission computed tomography (SPECT) data obtained from five patients treated at our institutions and also reviewed four previous studies. Therefore, SPECT findings in a total of 19 cases were analyzed, including 16 patients with temporal lobe epilepsy (TLE). During nonpsychotic states, the laterality of epileptic foci was judged as left-sided in nine episodes, right-sided in six episodes, and nonlateralized in four episodes. In PIP states, 88% of the patients showed a relative increase of right temporal perfusion (increased right temporal or decreased left temporal perfusion). Regardless of whether right- or left-sided pathology was suspected during a nonpsychotic state, SPECT findings obtained during PIP episodes revealed a trend of right-sided temporal predominance.     

The role of neuroimaging in the surgical treatment of epilepsy

ABSTRACT— Resective surgical treatment of medically intractable epilepsy requires accurate identification of the site and extent of the epileptogenic zone responsible for habitual seizures. Epileptogenicity per se is demonstrated electrophysiologically, but interictal and ictal EEG transients, whether recorded extracranially or intracranially, propagate widely and can give rise to false lateralizing and false localizing information. Neuroimaging techniques provide additional important information which greatly enhances confidence in localization derived electrophysiologically. Structural imaging with X-ray computed tomography and magnetic resonance imaging, as well as functional imaging with positron emission tomography, single photon emission computed tomography, and computerized mapping of electromagnetic activity, used together with other tests of focal functional deficit, 1) increase the confidence with which surgical resection can be performed on the basis of noninvasive tests alone, 2) aid in developing appropriate strategy for intracranial electrode recording when this is necessary, and 3) supplement results of invasive studies sufficiently to justify surgical resection in some patients who otherwise might be rejected for surgery. Addition of these new techniques, therefore, has increased the number of patients considered candidates for surgery, decreased the number of invasive procedures necessary before surgery can be performed, and increased the accuracy of surgical resection.     

HMPAO SPECT in non-epileptic seizures: preliminary results

The diagnosis of non-epileptic seizures (NES) is problematic. Although diagnosis can be achieved by videotelemetry, these facilities are expensive and not widely available. HMPAO SPECT studies show focal hypoperfusion interictally in focal epilepsy. SPECT has not been studied in any detail in NES previously. Two groups (10 patients each) were studied, one with NES and one with complex partial seizures and localisation related epilepsy. SPECT scans were normal in 7 of 10 (70%) NES patients, while showing clear focal hypoperfusion in 8 of 10 patients (80%) with epilepsy. In the NES group, 1 patient showed hypoperfusion indistinguishable from that seen in epilepsy, while 2 patients in the epilepsy group showed only equivocal focal hypoperfusion. The remaining 2 patients in the NES group showed bifrontal and equivocal focal hypoperfusion. A normal HMPAO SPECT study supports the diagnosis of NES in patients with seizures of uncertain aetiology.     

Patients with West syndrome whose ictal SPECT showed focal cortical hyperperfusion

To clarify the mechanism of clustered spasms in West syndrome (WS), we examined ictal SPECT and EEG, as well as those during the interictal period, in three patients with symptomatic WS who had apparent focal cerebral lesions. For ictal SPECT and EEG, we monitored the patients with EEG, and as soon as we noticed the occurrence of clustered spasms clinically and electroencephalographically, [(99m)Tc]ECD was injected intravenously and flushed thoroughly with saline. In these three patients, regional cerebral blood flow (rCBF) increased during ictus and decreased during the interictal period in the area that coincided with the focal cerebral lesion recognized by CT/MRI. The ictal hyperperfusion of bilateral basal ganglia was also detected in two of the three patients. The ictal EEG showed a diffuse slow wave complex corresponding to a clinical spasm. The sharp waves that preceded the diffuse slow wave complex and the spasm appeared in the same area in which rCBF increased during ictus. None of the patients showed partial seizure before or after clustered spasms clinically or electroencephalographically during the ictal SPECT study. Secondary generalization from a cerebral focus may explain the mechanism of spasms in these patients with WS: focal cortical discharge may primarily generate clustered spasms and trigger the brainstem and basal ganglia structures to produce spasms.     

Hot water epilepsy: Phenotype and single photon emission computed tomography observations

We studied the anatomical correlates of reflex hot water epilepsy (HWE) using multimodality investigations viz. magnetic resonance imaging (MRI), electroencephalography (EEG), and single photon emission computed tomography (SPECT). Five men (mean age: 27.0 ΁ 5.8 years) with HWE were subjected to MRI of brain, video-EEG studies, and SPECT scan. These were correlated with phenotypic presentations. Seizures could be precipitated in three patients with pouring of hot water over the head and semiology of seizures was suggestive of temporal lobe epilepsy. Ictal SPECT showed hyperperfusion in: left medial temporal — one, left lateral temporal — one, and right parietal — one. Interictal SPECT was normal in all five patients and did not help in localization. MRI and interictal EEG was normal in all the patients. The clinical and SPECT studies suggested temporal lobe as the seizure onset zone in some of the patients with HWE.     

Decreased cerebral blood flow in the limbic and prefrontal cortex using SPECT imaging in a cohort of completed suicides

Suicide has a high comorbidity with impulsivity and depression, and finding imaging biomarkers indicative of patients at high risk for suicidal behavior is invaluable to the clinician. Using single-photon emission computed tomography (SPECT) imaging, we have previously reported regional cerebral blood flow (rCBF) decreases in the medial prefrontal cortex, ventral tegmental area and subgenual cingulate cortex (Brodmann area 25 (BA 25)), a region found to be hypoperfused with treatment-resistant depression. From 2007 to 2010, we have extended our analysis to include nine additional completed suicides. In all, 27 healthy, age- and gender-matched subjects from a previously acquired healthy brain study served as controls to our 21 completed suicides. All 21 suicides had been previously diagnosed with depression according to Diagnostic and Statistical Manual of Mental Disorder-IV criterion. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare the differences in technetium-99m hexamethylpropylene amine oxime brain uptake between the groups. Factor analysis of the data identified the top 10 regions of hypoperfusion in the suicidal group, including the bilateral superior frontal lobes, the right precuneus, the rolandic operculum, postcentral gyrus, left caudate and insular cortex. We also demonstrate more focal decreases in rCBF in the subgenual cingulate cortex (BA 25) in 18 subjects, supporting our previous hypothesis that hypoperfusion of BA 25 may be a risk factor for suicide in depressed patients. This work suggests that SPECT might be useful in predicting risk for suicide completion in subjects with depression or treatment-resistant depression. Further investigation of this work is necessary to better understand the predictive value of this finding.     

Single Photon Emission Computed Tomography (SPECT) in a Patient with Bilateral Temporal Seizures: Correlation Between Ictal EEG and Postictal/Ictal SPECT

Summary: We report a patient with bilateral independent temporal lobe seizures in whom two [^99mTc]HMPAO single photon emission computed tomograph (SPECT) scans were performed during two different seizures. In the first perüctal SPECT, [^99mTc]HMPAO was injected in the interval between two closely spaced seizures (one localized in the left temporal lobe and the other in the right temporal lobe). SPECT images showed hypoperfusion in the left lateral temporal lobe, hyper-perfusion of the left mesial temporal region, and pronounced hyperperfusion in the right anterior temporal lobe. These results suggest both a postictal left temporal SPECT pattern and an ictal right temporal pattern. In the second periictal SPECT, [^99mTc]HMPA was injected immediately after a right temporal lobe seizure and showed right lateral temporal lobe hypoperfusion and right mesial hyperperfusion, suggesting a postictal right temporal SPECT pattern. Interpretation of the periictal SPECT should take into account EEG changes at the time or in the minutes immediately after injection of [^99mTc] HMPAO.     

Three Years On Clomipramine: Before and After Brain SPECT Study

A case is presented of a patient diagnosed with attention deficit disorder, obsessive thinking, anger outbursts, and depression who had a SPECT study prior to treatment and after 3 years of treatment on clomipramine. The follow-up SPECT study showed marked improvement overall in the cerebral perfusion of the brain. At rest marked overactivity was noted in the anterior medial aspects of the frontal lobes, along with patchy (increased and decreased) uptake throughout the cortical and subcortical areas of the brain. After treatment for 3 years on clomipramine at 225 mg a day, the follow-up SPECT study revealed a normalization of activity in the anterior medial aspects of the frontal lobes as well as no patchy uptake cortically and subcortically as noted in the study prior to treatment. The clinical usefulness of the SPECT study as it relates to this case is discussed.     

Cerebral perfusion‐CT patterns following seizure

Background: Cerebral perfusion‐CT (PCT) is commonly used to image patients with suspected stroke, but PCT may also be useful in detecting abnormalities following seizure. Methods: We retrospectively identified patients who presented to our stroke center between 2000 and 2008 with acute, transient neurological deficits because of seizure and received PCT imaging within 72 h. We compared the group of seizure patients with abnormal post‐ictal PCT to a group of seizure patients with normal post‐ictal PCT. Patients were excluded from analysis if the seizure occurred secondary to an acute process known to alter cerebral perfusion. Results: Of 27 patients with acute post‐ictal neurological deficits, PCT was abnormal in 10 (37%) and normal in 17 (63%). The most common post‐ictal perfusion abnormality, seen in eight of 10 patients, was focal hypoperfusion, with prolonged mean transit time (MTT) and decreased cerebral blood flow and cerebral blood volume, in a cortical ribbon pattern, multi‐lobar or holo‐hemispheric distribution, sparing the basal ganglia. CT Angiography (CTA) showed no corresponding large vessel pathology. Two other PCT abnormalities – focal hyperperfusion and an isolated prolonged MTT – were also observed in single patients. Imaging within 2 h after seizure termination was significantly associated with finding a post‐ictal PCT abnormality (P < 0.039). Conclusions: Post‐ictal cerebral PCT abnormalities are relatively common in patients early after seizure. When PCT abnormalities occur in atypical vascular distributions – and the CTA shows no corresponding large vessel occlusions – seizure should be considered as a diagnostic possibility prior to giving acute stroke therapy.     

Symptomatic hyperperfusion after superficial temporal artery–middle cerebral artery anastomosis in a child with moyamoya disease

Object Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). It is undetermined, however, how rapid increase in CBF affects ischemic brain at acute stage, especially in children. Case report A 4-year-old girl with moyamoya disease underwent right superficial temporal artery–middle cerebral artery (STA–MCA) anastomosis. She suffered temporary left facial palsy 5 days after surgery. Postoperative N-isopropyl-p-[¹²³I]iodoamphetamine single-photon emission computed tomography (¹²³I-IMP-SPECT) revealed focal intense increase in CBF at the sites of anastomosis. Magnetic resonance imaging/angiography showed the apparently patent STA–MCA anastomosis as a thick high signal without ischemic changes. Her symptom improved 9 days after surgery, and single-photon emission computed tomography (SPECT) 2 months later showed normalization of CBF. Surgical revascularization completely relieved the transient ischemic attack on her left hand that was seen before surgery. Conclusion We demonstrated, for the first time, that delayed focal neurological deficit after STA–MCA anastomosis can be caused by focal hyperperfusion in childhood moyamoya disease.     

A dual-labeled Annexin A5 is not suited for SPECT imaging of brain cell death in experimental murine stroke

Cell death is one of the pathophysiological hallmarks after stroke. Markers to image cell death pathways in vivo are highly desirable. We previously showed that fluorescently labeled Annexin A5 (AnxA5), which binds specifically to phosphatidylserine (PS) on dead/dying cells, can be used in experimental stroke for monitoring cell death with optical imaging. Here we investigated whether dual-labeled AnxA5 (technetium and fluorescence label) can be used for single-photon emission computed tomography (SPECT) of cell death in the same model. C57Bl6/N mice were subjected to 60-minute middle cerebral artery occlusion (MCAO) and underwent SPECT imaging at 24, 48, and 72 hours afterwards. They were injected intravenously with either PS-binding AnxA5 or the nonfunctional AnxA5 (negative control), labeled with 99mTc and Alexa Fluor 568, respectively. After SPECT imaging, brain sections were cut for autoradiography and fluorescence microscopy. Ethanol-induced cell death in the femur muscle was used as positive control. We detected dual-labeled AnxA5 in the model of ethanol-induced cell death in the femur muscle, but not after MCAO at any time point, either with SPECT or with ex vivo autoradiography or fluorescence microscopy. Dual-labeled AnxA5 appears to be unsuited for visualizing death of brain cells in this MCAO model.     

Objective evaluation of cerebrovascular reactivity for acetazolamide predicts cerebral hyperperfusion after carotid artery stenting: Comparison with region of interest methods

Background and purpose

Hemodynamic impairments are considered risk factors of cerebral hyperperfusion after carotid artery stenting (CAS); measurement by Single-photon emission computed tomography (SPECT) using a subjective region of interest (ROI) method lacks consistency and reproducibility.

Acetazolamide challenge test using semiquantitative 123 I-IMP SPECT for detection of cerebral misery perfusion

The accuracy of the acetazolamide (ACZ) challenge test using semiquantitative SPECT in detecting Stage II hemodynamic failure, i.e. cerebral misery perfusion, in patients so diagnosed with PET has yet to be determined. This study was carried out in 53 patients who had a unilateral occlusion or severe stenosis of their cerebral artery. Asymmetry index (AI) was used to determine relative CBF distribution on each SPECT image. DeltaAI (regional vasodilatory capacity) values were compared with the values of several PET parameters. We also repeated SPECT and PET studies in 15 patients after a mean interval of 2.6 years from entry. The correlation between changes in DeltaAI and PET data were examined. The DeltaAI value closely correlated with the ipsilateral OEF value (r=-0.64, p<0.001). Sensitivity-specificity curve analysis revealed that the optimal cut-off value for detecting Stage II hemodynamic failure was -13.5% of DeltaAI, at which point the diagnostic accuracy was 82%. In follow-up studies, changes in DeltaAI correlated significantly with changes in OEF values (r=-0.68, p<0.01). Semiquantitative SPECT examination with ACZ challenge detects Stage II hemodynamic failure with a diagnostic accuracy of 82%. An improvement in reduced vasodilatory capacity as determined by SPECT coincides with a reduction in OEF values.