123I-IMP Single Photon Emission Computed Tomography Research Articles

Iodine-123-Iomazenil Single-Photon Emission Computed Tomography Revealed Recovery of Neuronal Viability in Association With Improvement of Cognitive Dysfunction After Revascularization in Moyamoya Disease.

Recent studies indicate that 123I-iomazenil (123I-IMZ) single-photon emission computed tomography (SPECT) can demonstrate neuronal viability. Although cognitive dysfunction has been recognized as an important issue in adult patients with moyamoya disease (MMD), no standard neuroradiological methods to define such conditions have been established. We examined the relationship between cognitive function and 123I-IMZ SPECT before and after revascularization in patients with MMD. The study participants were 16 adult patients with MMD whose cerebrovascular reactivities were decreased only on the surgical sides of combined revascularization. Cognitive function was examined using the Mini-Mental State Examination (MMSE; cutoff: 27) and the Frontal Assessment Battery (FAB; cutoff: 16) before and at 3 to 6 months after surgery. 123I-iodoamphetamine (123I-IMP) SPECT with acetazolamide challenge and 123I-IMZ SPECT were performed concurrently while evaluating cognitive function. The radioreactivities of 123I-IMZ SPECT in regions with decreased cerebrovascular reactivities on 123I-IMP SPECT were investigated using affected-to-contralateral side asymmetry ratio (IMZ-ACR). Twelve patients showed normal cognitive function (MMSE: 29.8 ± 0.4, FAB: 18 ± 0) before surgery. No evident laterality of 123I-IMZ uptake was seen (IMZ-ACR: 0.98 ± 0.04). Neither cognitive function nor 123I-IMZ SPECT worsened after surgery (MMSE: 29.8 ± 0.3, FAB: 18 ± 0, IMZ-ACR: 1.00 ± 0.04). By contrast, 4 patients presented cognitive dysfunction (MMSE: 24.3 ± 3.9, FAB: 14.8 ± 2.7) before revascularization. Preoperative imaging of these patients showed decreased 123I-IMZ uptake, and their IMZ-ACRs (0.83 ± 0.08) were significantly lower than those of the normal group. After revascularization, cognitive functions and 123I-IMZ uptake tended to ameliorate (MMSE: 27.5 ± 1.7, FAB: 16.3 ± 2.2, IMZ-ACR: 0.94 ± 0.09). Preoperative cognitive function was associated with 123I-IMZ uptake in adult patients with MMD. After revascularization, cognitive function could be recovered in the viable areas of the brain, which is consistent with 123I-IMZ SPECT findings.

Utility of combining multiple parameters of 123I-IMP SPECT and voxel-based morphometry MRI using a multiparametric scoring system for differentiating dementia with Lewy bodies from Alzheimer's disease.

Brain magnetic resonance imaging voxel-based morphometry (VBM) and perfusion single-photon emission computed tomography (SPECT) are useful for differentiating dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). To determine whether combining multiple parameters of VBM and SPECT using a multiparametric scoring system (MSS) improves diagnostic accuracy in differentiating DLB from AD. In total, 23 patients with DLB and 57 patients with AD underwent imaging using a voxel-based specific regional analysis system for AD (VSRAD), an easy Z-score imaging system, and a Z-Graph using three-dimensional stereotactic surface projection. The cutoff values were determined using the receiver operating characteristic curve to differentiate DLB from AD for all parameters. Patients were scored 1 (DLB) or 0 (AD) for each statistically significant parameter, according to a threshold. The total score was determined for each case to obtain a cutoff value for the MSS. The mean Z-scores in the medial temporal lobes using the VSRAD were significantly lower in patients with DLB than in those with AD. Each Z-score of the summed Z-scores in all four segmented regions of the occipital lobes using the Z-Graph was significantly higher in patients with DLB than in those with AD. Among the five parameters, the highest accuracy was 80% for the Z-score of the summed Z-scores in the left medial occipital lobe. For the MSS, a cutoff value of four improved the diagnostic accuracy to 82%. MSS was more accurate than any single parameter of VBM or SPECT in differentiating DLB from AD.

Cerebellar blood perfusion is a diagnostic, but not a prognostic, marker for parkinsonian-dominant type multiple system atrophy

IntroductionMultiple system atrophy (MSA) is clinically characterized by various neurological symptoms. According to the diagnostic criteria, MSA is classified into parkinsonian-dominant type (MSA-P) or cerebellar ataxia-dominant type (MSA-C) based on the predominant signs displayed. Recently, N-isopropyl-p-[123I] iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT), a radiological examination evaluating brain perfusion, has been successful in detecting cerebellar hypoperfusion in MSA-P patients, demonstrating its utility in the early detection of cerebellar dysfunction. In this study, we further explored whether this cerebellar hypoperfusion impacts the clinical features of MSA-P, whether it is observable in patients without cerebellar symptoms, and, most importantly, whether it influences the prognosis of MSA-P. MethodsWe conducted a retrospective analysis of 88 MSA patients who were admitted to our department for the last fifteen years. Clinical data were collected, and cerebellar perfusion was examined using 123I-IMP SPECT. This analysis includes the application of the three-dimensional stereotactic surface projection (3D-SSP) technique and Z-score. ResultsCerebellar perfusion decreased in MSA-P patients without cerebellar ataxia, compared to healthy individuals (p = 0.0017). The Receiver Operating Characteristic (ROC) curve demonstrated a moderate ability to distinguish MSA-P patients without cerebellar ataxia (MSA-Pp) from healthy controls (AUC = 0.6832). Among MSA-Pp, those exhibiting cerebellar hypoperfusion showed relatively improved neurological prognosis, although the difference was not statistically significant when compared to those with normal cerebellar perfusion. ConclusionAssessing cerebellar perfusion through IMP-SPECT proves valuable in detecting subclinical cerebellar dysfunction in MSA-Pp. Importantly, cerebellar hypoperfusion does not correlate with a poorer neurological prognosis.

A Bayesian estimation method for cerebral blood flow measurement by area-detector CT perfusion imaging.

Bayesian estimation with advanced noise reduction (BEANR) in CT perfusion (CTP) could deliver more reliable cerebral blood flow (CBF) measurements than the commonly used reformulated singular value decomposition (rSVD). We compared the efficacy of CBF measurement by CTP using BEANR and rSVD, evaluating both relative to N-isopropyl-p-[(123) I]- iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT) as a reference standard, in patients with cerebrovascular disease. Thirty-one patients with suspected cerebrovascular disease underwent both CTP on a 320 detector-row CT system and SPECT. We applied rSVD and BEANR in the ischemic and contralateral regions to create CBF maps and calculate CBF ratios from the ischemic side to the healthy contralateral side (CBF index). The analysis involved comparing the CBF index between CTP methods and SPECT using Pearson's correlation and limits of agreement determined with Bland-Altman analyses, before comparing the mean difference in the CBF index between each CTP method and SPECT using the Wilcoxon matched pairs signed-rank test. The CBF indices of BEANR and 123I-IMP SPECT were significantly and positively correlated (r = 0.55, p < 0.0001), but there was no significant correlation between the rSVD method and SPECT (r = 0.15, p > 0.05). BEANR produced smaller limits of agreement for CBF than rSVD. The mean difference in the CBF index between BEANR and SPECT differed significantly from that between rSVD and SPECT (p < 0.001). BEANR has a better potential utility for CBF measurement in CTP than rSVD compared to SPECT in patients with cerebrovascular disease.

Different hemodynamics of basal ganglia between moyamoya and non-moyamoya diseases using intravoxel incoherent motion imaging and single-photon emission computed tomography.

Moyamoya disease (MMD) and non-MMD have different pathogenesis, clinical presentation, and treatment policy. To identify differences in hemodynamics between MMD and non-MMD using intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT). Patients who had undergone 99mTc-ECD or 123I-IMP SPECT, and IVIM imaging were retrospectively studied. IVIM imaging was acquired using six different b-values. Cerebral blood flow ratio (CBFR) in the basal ganglia was calculated using a standardized volume-of-interest template. The cerebellum was used as a reference region. IVIM perfusion fraction (f) was obtained using a two-step fitting algorithm. Elliptical regions of interest were placed in bilateral basal ganglia on the IVIM f map. Patients were classified into MMD and non-MMD groups. The correlation between CBFR and mean IVIM f (fmean) in the basal ganglia was evaluated using Spearman's rank correlation coefficient. In total, 20 patients with MMD and 28 non-MMD patients were analyzed. No significant differences in fmean were observed among MMD, affected hemisphere with non-MMD (non-MMDaff), and unaffected hemispheres with non-MMD (non-MMDunaff). A negative correlation was seen between fmean and CBFR in the MMD group (r = -0.40, P = 0.0108), but not in the non-MMD group (non-MMDaff, r = 0.07, P = 0.69; non-MMDunaff, r = -0.22, P = 0.29). No significant differences were found among MMD and non-MMD patients, irrespective of SPECT tracers. The combination of IVIM MRI and SPECT appears to allow non-invasive identification of differences in hemodynamics between MMD and non-MMD.

Arterial transit artifacts observed by arterial spin labeling in Moyamoya disease

Objectives: Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique used to assess cerebral perfusion. When tissue perfusion is impaired, such as in Moyamoya disease, a hyperintense band called the arterial transit artifact (ATA) may occur, which interferes with accurate measurements on ASL-MRI. In this study, we evaluated the correlation of ATAs with magnetic resonance angiography (MRA) and single-photon emission computed tomography (SPECT) imaging results in Moyamoya disease. The aim of our study was to elucidate the pathophysiology of ATAs and risk factors for high ATA scores. Materials and Methods: This retrospective study included 28 patients (56 hemispheres) with Moyamoya disease treated at our institution. MRI, MRA, ASL perfusion, and N-isopropyl-[123I] b-iodoamphetamine (123I-IMP) SPECT were performed. In order to semi-quantitatively evaluate the degree of ATA, the ATA scores were measured according to the number of hyperintense signal bands in the cerebral cortex. The relationship between the ATA scores and clinical and radiological factors were analyzed. Results: Regional cerebral blood flow (rCBF) determined with ASL weakly correlated with that determined by 123I-IMP SPECT (ρ=0.31, p=0.027). There was no significant association between the ATA scores and rCBF values determined with 123I-IMP SPECT (p=0.872, 0.745, 0.743 at PLD1000 (post-labeling delay), 1500, and 2000, respectively). However, there was a significant correlation between ATA scores and MRA scores (ρ=0.427 p=0.001; ρ=0.612 p=0.001; ρ=0.563 p=0.001 at PLD1000, 1500, and 2000, respectively). An analysis of patient background characteristics revealed a significantly higher incidence of high ATA scores in female patients, patients with high MRA scores, and patients with a distinguishable ivy sign. A multivariate analysis confirmed that female sex, high MRA score, and presence of an ivy sign were risk factors for high ATA scores. Conclusion: ATA scores were moderately correlated with MRA scores, and presence of an ivy sign was the most predictive factor for high ATA scores. A high ATA score determined using ASL in a patient with Moyamoya disease might suggest an advanced disease stage and a reduction in cerebrovascular reserve capacity.

Moyamoya disease with epileptic nystagmus: A case report

Epileptic nystagmus is a quick, repetitive, jerky movement of the eyeball caused by seizure activity, which is unaccompanied by other ictal phenomena. We report a case of moyamoya disease with epileptic nystagmus. A 23-year-old woman presented with a headache and transient hemiparesis on her left side. Magnetic resonance imaging showed no ischemic or hemorrhagic stroke lesions. Digital subtraction angiography confirmed stenosis of the terminal portion of the right internal carotid artery and the formation of moyamoya vessels on the right side. 123I-N-isopropyl-iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) showed decreased uptake in the right basal ganglia, frontal, and parietal regions. After electroencephalography (EEG) and a hyperventilation test were performed, nystagmus appeared and was accompanied with a declining level of consciousness. Ictal EEG during an attack showed no epileptiform discharge. Moreover, the patient sometimes experienced simultaneous upper limb-shaking and gelastic attacks. After superficial temporal artery to middle cerebral artery bypass surgery was performed on the right side, symptom frequency and duration gradually decreased. Decreased 123I-IMP SPECT blood flow in the right frontal region is considered a mechanism that causes the onset of epileptic nystagmus. It is presumed that the attack was caused by an ischemic abnormality in the saccade region of the frontal eye field. Moreover, revascularization can effectively treat the symptoms of moyamoya disease.

Assessment of Hemodynamic Compromise Using Computed Tomography Perfusion in Combination with 123I-IMP Single-Photon Emission Computed Tomography without Acetazolamide Challenge Test

The acetazolamide challenge test in conjunction with 123I-IMP single-photon emission computed tomography (SPECT) is a known method of assessing cerebrovascular reserve capacity. In this study, we investigated whether CT perfusion in combination with resting state 123I-IMP SPECT could be used instead of the acetazolamide challenge test to evaluate hemodynamic compromise in patients with atherosclerotic occlusive disease. Twenty consecutive patients with unilateral internal carotid artery or middle cerebral artery steno-occlusive disease were enrolled. 123I-IMP SPECT was performed with and without the acetazolamide challenge test, and with CT perfusion. Cerebral blood flow (CBF), cerebral blood volume, and mean transit time (MTT) obtained by CT perfusion were compared with CBF and cerebrovascular reactivity (CVR) obtained by 123I-IMP SPECT. The asymmetry ratio of MTT as measured by CT perfusion showed a strong correlation with the CVR to acetazolamide as measured by 123I-IMP SPECT (ρ = -.780, P <.001). Based on the CBF obtained through 123I-IMP SPECT and the MTT obtained through CT perfusion, hemodynamic compromise was detected with high sensitivity (1.000) and specificity (.929), and a cutoff value of 30% was found to be suitable for the asymmetry ratio of MTT. MTT prolongation was significantly improved after revascularization surgery in hemodynamic compromise (P = .028). MTT as measured by CT perfusion in combination with CBF as measured by resting state 123I-IMP SPECT may be useful for evaluating hemodynamic compromise as an alternative to the acetazolamide challenge test.

Early differential diagnosis between Alzheimer's disease and dementia with Lewy bodies: Comparison between 18F-FDG PET and 123I-IMP SPECT

Both 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and 123I-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) have been used for the differential diagnosis of Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). Less information is available, however, regarding the differential diagnosis of mild cognitive impairment (MCI) due to AD and MCI due to DLB. We examined nine AD patients (AD group), nine DLB patients (DLB group), eight MCI due to AD patients (MCI-AD group), and nine MCI due to DLB patients (MCI-DLB group) with FDG PET and IMP SPECT using a well-characterized normal database and a stereotactic extraction estimation method. In the AD and DLB groups, receiver operating characteristic (ROC) analysis in the occipital regions showed significant accuracy of both FDG PET and IMP SPECT for the differential diagnosis. In the MCI-AD and MCI-DLB groups, ROC analysis showed significant accuracy of only FDG PET for the differential diagnosis. Both FDG PET and IMP SPECT would be useful for the differential diagnosis between AD and DLB. For the differential diagnosis of MCI-AD versus MCI-DLB, FDG PET would be more useful than IMP SPECT.

Adult phenylketonuria presenting with subacute severe neurologic symptoms

We report a 48-year-old Japanese woman with phenylketonuria (PKU) who presented with severe neurological symptoms more than 30years after discontinuation of dietary treatment. She was diagnosed with PKU at 6-years-old and was treated with a phenylalanine restricted diet until she was 15years old. When she was 48-years-old she started having difficulty walking. After several months, she presented with severe disturbance of consciousness and was admitted. She was diagnosed as having neurological complications associated with PKU. We observed temporal changes in her laboratory data, brain MRI and single-photon emission computed tomography (SPECT) scan findings. Brain MRI on T2-weighted, fluid-attenuated inversion recovery and diffusion-weighted images revealed high intensity lesions in her bilateral frontal lobes and 123I-IMP SPECT showed marked and diffuse hypoperfusion in the bilateral cerebrum and cerebellum. After the resumption of dietary treatment, serum phenylalanine concentrations immediately decreased to the normal range. However, her neurological symptoms took longer to improve. We also found no clear temporal association between MRI findings and clinical severity. SPECT abnormalities showed marked improvement after treatment. It is well known that PKU patients who discontinue the dietary restriction from their childhood develop minor neurological impairments. However, PKU patients with late-onset severe neurological symptoms are very rare. To our knowledge, this is the first report regarding SPECT findings of PKU patients with late-onset severe neurological deterioration.

Does preoperative measurement of cerebral blood flow with acetazolamide challenge in addition to preoperative measurement of cerebral blood flow at the resting state increase the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy? Results from 500 cases with brain perfusion single-photon emission computed tomography study.

The purpose of the present study was to determine whether preoperative measurement of cerebral blood flow (CBF) with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy (CEA). CBF at the resting state and cerebrovascular reactivity (CVR) to acetazolamide were quantitatively assessed using N-isopropyl-p-[123I]-iodoamphetamine (IMP)-autoradiography method with single-photon emission computed tomography (SPECT) before CEA in 500 patients with ipsilateral internal carotid artery stenosis (≥ 70%). CBF measurement using 123I-IMP SPECT was also performed immediately and 3 days after CEA. A region of interest (ROI) was automatically placed in the middle cerebral artery territory in the affected cerebral hemisphere using a three-dimensional stereotactic ROI template. Preoperative decreases in CBF at the resting state [95% confidence intervals (CIs), 0.855 to 0.967; P = 0.0023] and preoperative decreases in CVR to acetazolamide (95% CIs, 0.844 to 0.912; P < 0.0001) were significant independent predictors of post-CEA hyperperfusion. The area under the receiver operating characteristic curve for prediction of the development of post-CEA hyperperfusion was significantly greater for CVR to acetazolamide than for CBF at the resting state (difference between areas, 0.173; P < 0.0001). Sensitivity, specificity, and positive- and negative-predictive values for the prediction of the development of post-CEA hyperperfusion were significantly greater for CVR to acetazolamide than for CBF at the resting state (P < 0.05, respectively). The present study demonstrated that preoperative measurement of CBF with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of the development of post-CEA hyperperfusion.

Combination of blood flow asymmetry in the cerebral and cerebellar hemispheres on brain perfusion SPECT predicts 5-year outcome in patients with symptomatic unilateral major cerebral artery occlusion

Background and objective: Misery perfusion increases the risk of stroke recurrence in patients with symptomatic major cerebral artery occlusion. The ratio of brain perfusion contralateral-to-affected asymmetry in the cerebellar hemisphere to brain perfusion affected-to-contralateral asymmetry in the cerebral hemisphere (CblPR/CbrPR) indicates affected-to-contralateral asymmetry of oxygen extraction fraction (OEF) in the cerebral hemisphere. The purpose of the present study was to determine whether the CblPR/CbrPR on brain perfusion single-photon emission computed tomography (SPECT) predicts 5-year outcomes in patients with symptomatic unilateral occlusion of the middle cerebral artery (MCA) or internal carotid artery (ICA).Methods: Brain perfusion was assessed using N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) SPECT in 70 patients. A region of interest (ROI) was manually placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres, and the CblPR/CbrPR was calculated. All patients were prospectively followed for 5 years. The primary end points were stroke recurrence or death.Results: A total of 17 patients exhibited the primary end points, 11 of whom experienced subsequent ipsilateral strokes. Multivariate analysis revealed that only high CblPR/CbrPR was significantly associated with the development of the primary end point or subsequent ipsilateral strokes (95% confidential limits [CIs], 1·130–3·145; P = 0·0114 or 95% CIs, 2·558–5·140; P = 0·0045, respectively). The CblPR/CbrPR provided 65% (11/17) or 91% (10/11) sensitivity and 88% (47/53) or 88% (52/59) specificity in predicting the primary end point or subsequent ipsilateral strokes, respectively.Conclusions: The CblPR/CbrPR on brain perfusion SPECT predicts 5-year outcomes in patients with symptomatic unilateral occlusion of the MCA or ICA.

Detection of misery perfusion in the cerebral hemisphere with chronic unilateral major cerebral artery steno-occlusive disease using crossed cerebellar hypoperfusion: comparison of brain SPECT and PET imaging

PurposeIn patients with unilateral internal carotid or middle cerebral artery (ICA or MCA) occlusive disease, the degree of crossed cerebellar hypoperfusion that is evident within a few months after the onset of stroke may reflect cerebral metabolic rate of oxygen in the affected cerebral hemisphere relative to that in the contralateral cerebral hemisphere. The aim of the present study was to determine whether the ratio of blood flow asymmetry in the cerebellar hemisphere to blood flow asymmetry in the cerebral hemisphere on positron emission tomography (PET) and single photon emission computed tomography (SPECT) correlates with oxygen extraction fraction (OEF) asymmetry in the cerebral hemisphere on PET in patients with chronic unilateral ICA or MCA occlusive disease and whether this blood flow ratio on SPECT detects misery perfusion in the affected cerebral hemisphere in such patients.MethodsBrain blood flow and OEF were assessed using 15O-PET and N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) SPECT, respectively. All images were anatomically standardized using SPM2. A region of interest (ROI) was automatically placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres using a three-dimensional stereotaxic ROI template, and affected-to-contralateral asymmetry in the MCA territory or contralateral-to-affected asymmetry in the cerebellar hemisphere was calculated. Sixty-three patients with reduced blood flow in the affected cerebral hemisphere on 123I-IMP SPECT were enrolled in this study.ResultsA significant correlation was observed between MCA ROI asymmetry of PET OEF and the ratio of cerebellar hemisphere asymmetry of blood flow to MCA ROI asymmetry of blood flow on PET (r = 0.381, p = 0.0019) or SPECT (r = 0.459, p = 0.0001). The correlation coefficient was higher when reanalyzed in a subgroup of 43 patients undergoing a PET study within 3 months after the last ischemic event (r = 0.541, p = 0.0001 for PET; r = 0.609, p < 0.0001 for SPECT). The blood flow ratio on brain perfusion SPECT in all patients provided 100 % sensitivity and 58 % specificity, with 43 % positive and 100 % negative predictive values for detecting abnormally elevated MCA ROI asymmetry of PET OEF.ConclusionThe ratio of blood flow asymmetry in the cerebellar hemisphere to blood flow asymmetry in the cerebral hemisphere on PET and SPECT correlates with PET OEF asymmetry in the cerebral hemisphere, and this blood flow ratio on SPECT detects misery perfusion in the affected cerebral hemisphere.

Abstract TP139: Usefulness of Staged Angioplasty for Carotid Artery Stenting

Introduction: Hyperperfusion syndrome is one of the most serious complications after carotid revascularization. We report the efficacy of staged angioplasty (SAP) for patients with severely impaired cerebral vasoreactivity. Methods: From April 2008 to March 2012, seventeen of 83 patients with high-grade internal carotid artery stenosis were considered at high risk of postoperative hyperperfusion based on the results of preoperative single-photon emission computed tomography (SPECT) with acetazolamide. They were treated with SAP which consists of mild balloon angioplasty (1st stage) and carotid artery stenting one month later (2nd stage). Rest 123I-IMP SPECT was performed to evaluate hyperperfusion just after the procedure of each stage. Results: Before we induced SAP procedure, 1.9%(3 of 158) of patients treated with CAS had a hemorrhagic complication due to hyperperfusion. None of 17 patients treated with SAP had hyperperfusion phenomenon on SPECT, and a hemorrhagic complication. The mean rate of stenosis was 91% before treatment, 70% after 1st stage, 21% after 2nd stage. Although stenosis had been worsened during the period between 1st and 2nd stages in four patients, all patients showed satisfactory recovery of cerebral blood flow after 2nd stage. Conclusions: In selected patients, SAP is effective and relatively safe to decrease hyperperfusion syndrome after procedures. However, method to choose high-risk patient for postoperative hyperperfusion and protocol of treatment are still controversial.

Crossed cerebellar hyperperfusion without restricted diffusion in status epilepticus

Crossed cerebellar diaschisis (CCD) has originally been reported as metabolic depression on positron emission tomography in the cerebellar hemisphere contralateral to supratentorial infarction [1]. CCD has currently been documented in status epilepticus using magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) [2]. However, combined diffusion and perfusion profiles have remained controversial in CCD with status epilepticus. A 46-year-old woman was admitted to our hospital for the treatment of status epilepticus. Nine days before admission, she had presented with convulsion in the left limbs and been admitted to another hospital. Her convulsion was initially controlled with intravenous diazepam, but subsequent treatment with several anti-epileptic drugs was unsuccessful and she was diagnosed with drug-induced rash. Upon admission to our hospital, a brain MRI revealed a small cyst in the right mesial temporal lobe, which was speculated as the seizure focus. T2-weighted MRI (T2WI) showed mild hyperintensity and edematous changes in the right frontal, posterior temporal, parietal, and occipital cortices, and the left cerebellar hemisphere (Fig. 1a). Diffusion-weighted MRI (DWI) revealed mild hyperintensity and apparent diffusion coefficient (ADC) showed a slight increase in the T2WI hyperintensity regions of the right cerebral cortex; ADC values were mildly higher in the right temporal cortex (8.37 9 10 ± 7.04 9 10 mm/s) than in the contralateral area (7.90 9 10 ± 1.77 9 10 mm/s). On the other hand, ADC values were similar in the bilateral cerebellar hemispheres (right, 6.07 9 10 ± 4.06 9 10 mm/s; left, 6.08 9 10 ± 5.43 9 10 mm/s; Fig. 1b). I-Iodoamphetamine (IMP) SPECT, which reflects brain perfusion, revealed hyperperfusion in these regions (Fig. 1c). Carbamazepine, which had been spared because of the druginduced skin lesions, was prescribed in combination with steroids, and her seizures were finally controlled. T2WI intensity was normal 2 weeks after admission (Fig. 1d). I-IMP SPECT performed on the same day showed mild hyperperfusion in the right cerebral cortex and symmetric perfusion in the cerebellar hemispheres (Fig. 1e). MRI studies were performed on a 3-T instrument (Signa EXCITE HD 3.0T, GE Medical Systems, Milwaukee, WI, USA) with a standard quadrature head coil. The parameters of DWI were as follows: time of repetition = 10,000 ms, time of echo = 86.6 ms, field of view = 24 cm, matrix size = 128 9 128 with echo planar sequence, b value = 1,500 s/mm, and slice thickness/gap = 5/1 mm. This study has been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki. Neuroimaging studies of the present case demonstrated crossed hyperintensity on T2WI concurrent with hyperperfusion on SPECT. Of note, ADC was mildly increased, not decreased, in the present case. Previous reports of CCD in status epilepticus have documented DWI hyperintensity of the ipsilateral cortical ribbon and the contralateral cerebellar hemisphere [2, 3]. Restricted diffusion (reduced ADC) has been speculated, without clear evidence, in the DWI hyperintensity lesions of CCD in status epilepticus [2, 3], which contradicts our observations. K. Fujita (&) Y. Izumi R. Kaji Department of Clinical Neuroscience, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan e-mail: kof@clin.med.tokushima-u.ac.jp

Arterial Spin-Labeling Magnetic Resonance Imaging After Revascularization of Moyamoya Disease

Arterial spin labeling (ASL) magnetic resonance imaging (MRI) is a technique for depicting cerebral perfusion without contrast medium. The purpose of this study was to determine whether ASL can be used to detect hyperperfusion after revascularization for moyamoya disease as effectively as N-isopropyl-[123I]β-iodoamphetamine ((123)I-IMP) single-photon emission computed tomography (SPECT). Fifteen consecutive patients with moyamoya disease were included in the study. All patients underwent surgical revascularization. Postoperatively, regional cerebral blood flow (rCBF) was measured by flow-sensitive alternating inversion recovery (FAIR) ASL and (123)I-IMP SPECT during the acute stage, and rCBF of the operative side was compared with the other side. The asymmetry ratio (AR) was then calculated from the rCBF as measured using each modality. The postoperative AR of ASL was moderately correlated with that of (123)I-IMP SPECT (y = 0.180x + 0.819; R = 0.80; P = .0003). In this series, 2 patients (13.3%) suffered symptomatic hyperperfusion after revascularization and accordingly exhibited increased AR of ASL. Our data indicate that early increases in rCBF in patients with hyperperfusion could be detected using FAIR ASL supplemental to (123)I-IMP SPECT after revascularization. Our data indicate that FAIR ASL is a convenient method for evaluating hyperperfusion that can be performed repeatedly without the use of contrast medium or radioisotopes.

Azelnidipine, a long-acting calcium channel blocker, could control hypertension without decreasing cerebral blood flow in post-ischemic stroke patients. A 123I-IMP SPECT follow-up study

Azelnidipine, a long-acting calcium channel blocker, is highly lipid soluble and selective for the vascular wall, and is expected to have an increasing effect on cerebral blood flow (CBF). The aim of this study is to investigate its safety and efficacy in stroke patients in the chronic stage as far as CBF is concerned using N-isopropyl-p-(123)I-iodo amphetamine ((123)I-IMP) single-photon emission computed tomography (SPECT). The patients were orally administered 8 or 16 mg of azelnidipine. Regional CBF was evaluated by (123)I-IMP SPECT using three-dimensional stereotactic region-of-interest (ROI) template (3D-SRT), a technique using anatomical standardization and ROI template consisting of 636 ROIs for the whole brain. Mean hemispheric CBF was defined as the mean value of the corpus callosum, and the precentral, central, parietal, angular and temporal gyri. Mean hemispheric and regional CBF after 1, 3 and 6 months were analyzed using a one-way repeated-measures analysis of variance. Ten post-ischemic stroke patients with hypertension were enrolled between October 2005 and October 2007, and all of them were well controlled with normal blood pressure (before: 172.3+/-16.6/88.4+/-14.0 mm Hg; 6 months: 128.7+/-15.9/70.9+/-10.1 mm Hg). No vascular events were observed during the study period. The mean hemispheric CBF was maintained during the study period (before: 46.0+/-9.7 ml per 100 g per min; 6 months: 49.3+/-11.1 ml per 100 g per min). The regional CBF was also maintained. In the chronic stage of ischemic stroke, azelnidipine could safely decrease systemic blood pressure without decreasing CBF.

Reduced Perfusion Reserve in Leukoaraiosis Demonstrated Using Acetazolamide Challenge 123I-IMP SPECT

We examined the relationship between the perfusion reserve as measured by acetazolamide (ACZ)-challenge N-isopropyl-I-123-p-iodoamphetamine (IMP)-single-photon emission computed tomography (SPECT) and the degree of leukoaraiosis (LA) as estimated using magnetic resonance imaging. In 51 patients receiving IMP-SPECT with the resting state and ACZ challenge, the unaffected cerebral hemispheres were included in the present study. Mean cerebral blood flow (CBF) in the resting state and ACZ reactivity were acquired. Absolute CBF value and ACZ reactivity were compared among patients with LA grades 0, 1, and 2. The relationship between mean age and LA grade was also assessed. No significant difference in the absolute CBF value in the resting state was observed among the 3 LA groups. Although vasoreactivity in LA grade 0 did not differ from that in grade 1, vasoreactivity in LA grade 2 was significantly lower (P < 0.05) than that in grades 0 or 1. The perfusion reserve is impaired in advanced LA.

Constant blood flow reduction in premotor frontal lobe regions in ALS with dementia – a SPECT study with 3D-SSP

OBJECTIVES - We investigated the regional cerebral blood flow in amyotrophic lateral sclerosis with dementia (ALS-D) patients, using single photon emission computed tomography (SPECT). MATERIALS AND METHODS - The (123)I-IMP SPECT data for 5 ALS-D and 16 ALS patients were analyzed using three-dimensional stereotactic surface projection (3D-SSP). RESULTS - 3D-SSP demonstrated marked prefrontal hypoperfusion in all the five ALS-D cases and significant bilateral prefrontal hypoperfusion in group comparisons. CONCLUSIONS - This study revealed prefrontal hypoperfusion in ALS-D cases to be an obvious abnormality with scientific objectivity.

Clinical role of 123I-IMP SPECT for the differential diagnosis of ocular malignant melanoma: A time-course analysis

To evaluate the efficacy of (123)I-IMP single photon emission computed tomography (SPECT) for the diagnosis of ocular malignant melanoma (MM). Thirty-eight patients (18 males, 20 females) clinically suspected of having ocular MM were retrospectively examined in this study. The age of patients ranged from 8 to 81 years (mean 55.6 years). Twelve patients were finally diagnosed as having ocular MM. Orbital SPECT images were taken 15 min, 4 h, 24 h and 48 h after intravenous injection of 111-222 MBq (3-6 mCi) (123)I-IMP. (123)I-IMP uptake in the orbital tumor was visually evaluated as-(negative),+/-(equivocal), or+(positive). The uptake index (UI) and increase ratios (IRs) were calculated. For visual evaluation, the accuracy of (123)I-IMP for the diagnosis of MM was 73.7% (15 min), 81.6% (4 h), 81.6% (24 h) and 86.8% (48 h). When UI and IR were calculated on both the MM and non-MM groups, the UI and IR of the MM group were significantly higher than those of the non-MM group (P<0.001). Moreover, the highest sensitivity (100%) and accuracy (94.7%) were obtained 48 h after (123)I-IMP administration when the cut-off value of UI was defined as 1.90. This study shows that (123)I-IMP SPECT is useful for the diagnosis of ocular MM. The UI values 48 h after the injection were efficient for the differentiation between MM and non-MM lesions.