Regional Cerebral Blood Flow SPECT Research Articles

The Value of Regional Cerebral Blood Flow SPECT and FDG PET in Operculoinsular Epilepsy.

Operculoinsular epilepsy (OIE) can be challenging to diagnose. While the value of SPECT cerebral blood flow and PET F-FDG studies for presurgical evaluation of patients with medial temporal lobe epilepsy (MTLE) is well established, it remains unclear whether they can help identify an operculoinsular epileptic focus. This study assesses the value of interictal/ictal regional cerebral blood flow (rCBF) SPECT and FDG PET for OIE diagnosis. Eighteen patients with proven OIE who underwent interictal/ictal rCBF SPECT and/or FDG-PET prior to epilepsy surgery were identified from our clinical database and were compared with a group of 18 patients who underwent MTLE surgery. Regional cerebral blood flow SPECT and FDG PET images were reevaluated visually by an expert reader blind to clinical data. Interictal/ictal rCBF SPECT correctly identified an operculoinsular focus in 11 (65%) of 17 OIE patients and was misleading in 3 cases (18%). Secondary activation in areas connected to the insula was often observed. In the MTLE group, the area of maximal increased perfusion was congruent in 12 (75%) of 16 patients and extended to the ipsilateral insula in 1 patient. FDG PET findings were concordant with the epileptic focus in 8 (47%) of 17 OIE patients and were misleading in 4 (24%), whereas they were concordant in all MTLE patients. Interictal/ictal rCBF SPECT can identify a concordant operculoinsular focus in a significant proportion of OIE patients and offers a valuable diagnostic tool in nonlesional cases. By contrast, the value of interictal FDG PET in this population is more equivocal.

A semi-quantitative method for correlating brain disease groups with normal controls using SPECT: Alzheimer's disease versus vascular dementia

PurposeTo demonstrate the utility of semi-quantitative circumferential-profile analysis of regional cerebral blood flow (rCBF) SPECT in Alzheimer's disease (AD) versus white matter vascular dementia (WM-VaD). MethodsSubjects underwent dementia evaluation, MRI and Tc-99m HMPAO SPECT. rCBF patterns from 11 AD and 20 WM-VaD patients were compared to 17 controls using semi-quantitative circumferential-profile analysis. ResultsAD patients showed more significant semi-quantitative circumferential-profile reductions in the posterior temporo-parietal regions, whereas WM-VaD patients demonstrated greater reductions involving the frontal regions of the brain. ConclusionSemi-quantitative circumferential-profile analysis provides a practical semi-quantitative method to evaluate brain SPECT scans in AD versus WM-VaD patients.

Recovery from Transient Global Amnesia Following Restoration of Hippocampal and Fronto–Cingulate Perfusion

A patient who suffered a transient global amnesia (TGA) attack underwent regional cerebral blood flow (rCBF) SPECT imaging and neuropsychological testing in the acute phase, after one month and after one year. Neuropsychological testing in the acute phase showed a pattern of anterograde and retrograde amnesia, whereas memory was within age normal limits at follow up. SPECT data were analysed with a within subject comparison and also compared with those of a group of healthy controls. Within subject comparison between the one month follow up and the acute phase detected increases in rCBF in the hippocampus bilaterally; further rCBF increases in the right hippocampus were detected after one year. Compared to controls, significant hypoperfusion was found in the right precentral, cingulate and medial frontal gyri in the acute phase; after one month significant hypoperfusion was detected in the right precentral and cingulate gyri and the left postcentral gyrus; after one year no significant hypoperfusion appeared. The restoration of memory was paralleled by rCBF increases in the hippocampus and fronto-limbic-parietal cortex; after one year neither significant rCBF differences nor cognitive deficits were detectable. In conclusion, these data indicate that TGA had no long lasting cognitive and neural alterations in this patient.

Recovery from transient global amnesia following restoration of hippocampal and fronto - cingulate perfusion.

A patient who suffered a transient global amnesia (TGA) attack underwent regional cerebral blood flow (rCBF) SPECT imaging and neuropsychological testing in the acute phase, after one month and after one year. Neuropsychological testing in the acute phase showed a pattern of anterograde and retrograde amnesia, whereas memory was within age normal limits at follow up. SPECT data were analysed with a within subject comparison and also compared with those of a group of healthy controls. Within subject comparison between the one month follow up and the acute phase detected increases in rCBF in the hippocampus bilaterally; further rCBF increases in the right hippocampus were detected after one year. Compared to controls, significant hypoperfusion was found in the right precentral, cingulate and medial frontal gyri in the acute phase; after one month significant hypoperfusion was detected in the right precentral and cingulate gyri and the left postcentral gyrus; after one year no significant hypoperfusion appeared. The restoration of memory was paralleled by rCBF increases in the hippocampus and fronto-limbic-parietal cortex; after one year neither significant rCBF differences nor cognitive deficits were detectable. In conclusion, these data indicate that TGA had no long lasting cognitive and neural alterations in this patient.

Diagnosis of Regional Cerebral Blood Flow Abnormalities Using Spect: Agreement between Individualized Statistical Parametric Maps and Visual Inspection by Nuclear Medicine Physicians with Different Levels of Expertise in Nuclear Neurology

INTRODUCTION:Visual analysis is widely used to interpret regional cerebral blood flow (rCBF) SPECT images in clinical practice despite its limitations. Automated methods are employed to investigate between-group rCBF differences in research studies but have rarely been explored in individual analyses.OBJECTIVES:To compare visual inspection by nuclear physicians with the automated statistical parametric mapping program using a SPECT dataset of patients with neurological disorders and normal control images.METHODS:Using statistical parametric mapping, 14 SPECT images from patients with various neurological disorders were compared individually with a databank of 32 normal images using a statistical threshold of p<0.05 (corrected for multiple comparisons at the level of individual voxels or clusters). Statistical parametric mapping results were compared with visual analyses by a nuclear physician highly experienced in neurology (A) as well as a nuclear physician with a general background of experience (B) who independently classified images as normal or altered, and determined the location of changes and the severity.RESULTS:Of the 32 images of the normal databank, 4 generated maps showing rCBF abnormalities (p<0.05, corrected). Among the 14 images from patients with neurological disorders, 13 showed rCBF alterations. Statistical parametric mapping and physician A completely agreed on 84.37% and 64.28% of cases from the normal databank and neurological disorders, respectively. The agreement between statistical parametric mapping and ratings of physician B were lower (71.18% and 35.71%, respectively).CONCLUSION:Statistical parametric mapping replicated the findings described by the more experienced nuclear physician. This finding suggests that automated methods for individually analyzing rCBF SPECT images may be a valuable resource to complement visual inspection in clinical practice.

Effets de l’âge et du genre sur la perfusion cérébrale régionale étudiée par deux méthodes d’analyse statistique voxel-par-voxel

Fully automated analysis programs have been applied more and more to aid for the reading of regional cerebral blood flow SPECT study. They are increasingly based on the comparison of the patient study with a normal database. In this study, we evaluate the ability of Three-Dimensional Stereotactic Surface Projection (3D-SSP) to isolate effects of age and gender in a previously studied normal population. The results were also compared with those obtained using Statistical Parametric Mapping (SPM99). Methods Eighty-nine 99mTc-ECD-SPECT studies performed in carefully screened healthy volunteers (46 females, 43 males; age 20–81 years) were analysed using 3D-SSP. A multivariate analysis based on the general linear model was performed with regions as intrasubject factor, gender as intersubject factor and age as covariate. Results Both age and gender had a significant interaction effect with regional tracer uptake. An age-related decline ( p < 0.001) was found in the anterior cingulate gyrus, left frontal association cortex and left insula. Bilateral occipital association and left primary visual cortical uptake showed a significant relative increase with age ( p < 0.001). Concerning the gender effect, women showed higher uptake ( p < 0.01) in the parietal and right sensorimotor cortices. An age by gender interaction ( p < 0.01) was only found in the left medial frontal cortex. The results were consistent with those obtained with SPM99. Conclusion 3D-SSP analysis of normal rCBF variability is consistent with the literature and other automated voxel-based techniques, which highlight the effects of both age and gender.

The prediction of cognitive decline in cognitive intact subjects using regional cerebral blood flow SPECT: A communty-based study

The prediction of cognitive decline in cognitive intact subjects using regional cerebral blood flow SPECT: A communty-based study

The prediction of cognitive decline in cognitive intact subjects using regional cerebral blood flow SPECT: A communty-based study

The prediction of cognitive decline in cognitive intact subjects using regional cerebral blood flow SPECT: A communty-based study

Are there adaptive changes in the human brain of patients with Parkinson’s disease treated with long-term deep brain stimulation of the subthalamic nucleus? A 4-year follow-up study with regional cerebral blood flow SPECT

The aim of this follow-up study was to assess persistent motor and regional cerebral blood flow (rCBF) changes in patients with Parkinson's disease (PD) treated with high-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN). Ten PD patients with STN-DBS underwent three rCBF SPECT studies at rest, once preoperatively in the off-drug condition (T(0)), and twice postoperatively in the off-drug/off-stimulation conditions at 5 +/- 2 (T(1)) and 42 +/- 7 months (T(2)). Patients were assessed using the UPDRS, H&Y and S&E scales. SPM was used to investigate baseline rCBF changes from the preoperative condition to the postoperative conditions and the relationship between rCBF and UPDRS scores used as covariate of interest. Parkinsonian patients showed a clinical improvement which was significant only on follow-up at 42 months. The main effect of treatment from T(0) to T(1) was to produce baseline rCBF increases in the pre-supplementary motor area (pre-SMA), premotor cortex and somatosensory association cortex. From T(1) to T(2) a further baseline rCBF increase was detected in the pre-SMA (p < 0.0001). A correlation was detected between the slight improvement in motor scores and the rCBF increase in the pre-SMA (p < 0.0001), which is known to play a crucial role in clinical progression. Our study suggests the presence of adaptive functional changes in the human brain of PD patients treated with long-term STN-DBS. Such adaptive processes seem to occur in the pre-SMA and to play only a slightly beneficial role in terms of functional compensation of motor impairment.

Development of “super rapid dynamic SPECT,” and analysis of retention process of99mTc-ECD in ischemie lesions: Comparative study with133Xe SPECT

To analyze the retention process of technetium-99m ethyl cysteinate dimer (99mTc-ECD) in normal and ischemic lesions, we developed a super rapid dynamic SPECT system based on the CERASPECT (DSI, Inc., Waltham, MA, USA). The system made it possible to take a SPECT series every 2 seconds. Each SPECT series contains a maximum of 16 slices (6.6 mm slice interval) in a matrix size of 32 x 32. The sensitivity of this system is 175 kcps/MBq/ml/cm slice thickness, and resolution is 12 mm FWHM at the center of a 20 cm(phi) water phantom. Using the super rapid SPECT system, the kinetic behavior of the 99mTc-ECD during retention in normal and ischemic lesions was analyzed. Twenty patients with ischemic lesions that were clearly demonstrated by 133Xe-rCBF (regional cerebral blood flow) SPECT but unclear on static 99mTc-ECD SPECT were examined. For the dynamic SPECT, 700 MBq of 99mTc-ECD was injected intravenously, and dynamic SPECT data were acquired every 2 seconds during a 90-second period. The serial dynamic SPECT and time-activity curves at some lesions with reduced rCBF and at the contralateral normal brain were analyzed. These dynamic SPECT data were compared with conventional static 99mTc-ECD SPECT and quantitative 133Xe-rCBF SPECT. All of mildly or moderately reduced rCBF lesions on the 133Xe-rCBF SPECT were recognized as low activity regions only at the early phase (during about 2-20 sec or less), with the lesions then gradually vanishing. These lesions were not recognized on the conventional static SPECT taken after the dynamic study. The time-activity curve at the reduced rCBF lesion was lower than that of contralateral normal brain at the early phase, and overtook the activity in the normal region with a gradual increase. The early phase images of 99mTc-ECD SPECT within 20 seconds by the super rapid dynamic SPECT were very useful to the same extent as the 133Xe-rCBF SPECT for detecting mild or moderate ischemic lesions. This study suggests that esterase activity, participating in the ECD retention mechanism, may be tolerable to mild or moderate ischemia. This tolerance may be the main cause of the nonlinear relationship between ECD accumulation and cerebral blood flow.

Padrões de ativação cerebral em idosos sadios durante tarefa de memória verbal de reconhecimento: a single-photon emission computerized tomography study

INTRODUÇÃO: Estudos que utilizam as técnicas de PET, SPECT e ressonância magnética funcional têm permitido o mapeamento dos circuitos cerebrais ativados durante diversas tarefas cognitivas. O campo da memória declarativa tem sido um dos mais intensamente estudados. No presente estudo, usa-se a técnica de mapeamento do fluxo sangüíneo cerebral regional (FSCr) por SPECT para investigar mudanças na atividade cerebral durante uma tarefa de memória episódica, em voluntários idosos sadios (n=15). MÉTODOS: Duas avaliações de SPECT foram realizadas na mesma sessão, usando a técnica de dose dividida do traçador 99 m-Tc-HMPAO. Medidas de FSCr foram registradas durante uma tarefa de reconhecimento de material verbal previamente aprendido e durante uma tarefa-controle mais simples. Comparações de FSCr foram realizadas automaticamente, utilizando o programa Statistical Parametric Mapping (SPM). RESULTADOS: Observou-se aumento de FSCr durante a tarefa de memória em várias regiões cerebrais, incluindo: córtex pré-frontal lateral bilateralmente (mais acentuadamente à esquerda); porções posteriores e mediais de córtex parieto-occipital à esquerda; hemisférios cerebelares bilateralmente; e córtex temporal lateral bilateralmente (p&lt;0,001, não corrigido para comparações múltiplas). Foram observados também focos inesperados de diminuição de FSCr em cíngulo posterior direito, córtex orbitofrontal esquerdo, córtex temporal inferior direito e vérmis cerebelar esquerdo (p&lt;0,05, corrigido para comparações múltiplas). CONCLUSÃO: Esses resultados sugerem que circuitos neuronais multifocais são engajados durante memória de reconhecimento e replicam localizações cerebrais descritas anteriormente na literatura. O uso desse protocolo em pacientes com transtornos neuropsiquiátricos poderá permitir a investigação de anormalidades cerebrais subjacentes aos déficits de memória presentes nesses transtornos.

Statistical parametric mapping analysis of regional cerebral blood flow SPECT images of Alzheimerʼs disease patients with delusion

s: Abstracts of the British Nuclear Medicine Society Autumn Meeting. Southampton, 12-13 October 2000

Correction of scattered photons in Tc-99m imaging by means of a photopeak dual-energy window acquisition

We are proposing a new method for correcting of scattered photons in technetium-99m (99mTc) imaging by means of photopeak dual-energy window acquisition. This method consists of the simultaneous acquisition of two images and estimation of a scatter image included in the symmetric energy window (SW) image by the difference between these images. The scatter corrected image is obtained by subtracting the scatter image from the SW image. In order to evaluate this method, we imaged a planar and a SPECT phantom with cold lesions and calculated the contrast value with and without the scatter correction. In addition, we performed asymmetric energy window (ASW) imaging to compare with this scatter correction method for planar images. In the planar image with the tissue-equivalent material of 10 cm, the scatter correction method removed 32% of the counting rate of the SW image and improved from 0.81 to 0.94 of the contrast value for a 4 cm-diameter cold lesion, while the contrast value with the ASW was 0.87 for such a cold lesion. The scatter corrected SPECT image had a reduction of 18% of the counting rate of the SW SPECT image and improvement of approximately 11% in contrast for cold spot sizes larger than a 3 cm-diameter, compared with the SW SPECT image. In addition, a perfusion defect could be well visualized by this scatter correction method on 99mTc-HMPAO regional cerebral blood flow SPECT of a patient. Our proposed scatter correction method can improve both planar and SPECT images qualitatively and quantitatively.