Intracranial subarachnoid hemorrhage following cervical laminoplasty: a report of two cases.

Intracranial hemorrhage is a rare complication of spinal surgery. Case 1 was a 58-year-old man who underwent cervical laminoplasty. No apparent iatrogenic dural rupture or cerebrospinal fluid leakage was observed.

Single-subject statistical mapping of acute brain hypoxia in the rat following middle cerebral artery occlusion: a microPET study.

No study so far has attempted to map the 3D topography of brain hypoxia in the individual rat in vivo following middle cerebral artery occlusion (MCAo). In a previous microPET study, we reported that (18)F-fluoromisonidazole ((18)F-MISO) trapping in the brain after MCAo was specific for the hypoxic viable tissue. Here, we used (18)F-MISO microPET to map the 3D topography of brain hypoxia in the acute stage of permanent distal MCAo in individual spontaneously hypertensive rats.

Statistical parametric analysis of cerebral blood flow in vascular dementia with small-vessel disease using Tc-HMPAO SPECT.

Background: Subcortical ischemic vascular dementia (SVD) caused by small-artery disease is a major cause of dementia. It still remains unclear, however, whether SVD may present with localized regional cerebral blood flow (rCBF) changes. We aimed to clarify the local rCBF changes associated with dementia in patients with early-stage SVD.

Applications of nitroimidazole in vivo hypoxia imaging in ischemic stroke.

Background And Purpose: Nitroimidazole imaging is a promising contender for noninvasive in vivo mapping of brain hypoxia after stroke. However, there is a dearth of knowledge about the behavior of these compounds in the various pathophysiologic situations encountered in ischemic stroke. In this article we report the findings from a systematic review of the literature on the use of the nitroimidazoles to map hypoxia after stroke.

How reliable is perfusion MR in acute stroke? Validation and determination of the penumbra threshold against quantitative PET.

Background And Purpose: Perfusion magnetic resonance imaging (pMR) is increasingly used in acute stroke, but its physiologic significance is still debated. A reasonably good correlation between pMR and positron emission tomography (PET) has been reported in normal subjects and chronic cerebrovascular disease, but corresponding validation in acute stroke is still lacking.

Methods: We compared the cerebral blood flow (CBF), cerebral blood volume, and mean transit time (MTT) maps generated by pMR (deconvolution method) and PET ((15)O steady-state method) in 5 patients studied back-to-back with the 2 modalities at a mean of 16 hours (range, 7 to 21 hours) after stroke onset.

Effect of linearization correction on statistical parametric mapping (SPM): a 99mTc-HMPAO brain perfusion SPECT study in mild Alzheimer's disease.

Objective: Statistical parametric mapping (SPM) was employed to investigate the regional decline in cerebral blood flow (rCBF) as measured by 99mTc-hexamethyl propylene amine oxime (HMPAO) single photon emission computed tomography (SPECT) in mild Alzheimer's disease (AD). However, the role of the post reconstruction image processing on the interpretation of SPM, which detects rCBF pattern, has not been precisely studied. We performed 99mTc-HMPAO SPECT in mild AD patients and analyzed the effect of linearization correction for washout of the tracer on the detectability of abnormal perfusion.

Imaging of brain hypoxia in permanent and temporary middle cerebral artery occlusion in the rat using 18F-fluoromisonidazole and positron emission tomography: a pilot study.

In acute stroke, the target of therapy is the severely hypoxic but salvageable tissue. Previous human studies using 18F-fluoromisonidazole and positron emission tomography (18F-FMISO PET) have shown high tracer retention indicative of tissue hypoxia, which had normalized at repeat scan >48 h later. In the only validation study of 18F-FMISO, using ex vivo autoradiography in thread middle cerebral artery occluded (MCAo) rats, there was unexpected high uptake as late as 22 h after reperfusion, raising questions about the use of 18F-FMISO as a hypoxia tracer.

Deterioration of hemiparesis after recurrent stroke in the unaffected hemisphere: Three further cases with possible interpretation.

Background: The concept of neural reorganization after brain damage is already well established, and many previous studies have successfully reported the translocation of the neural activation in the motor-related cortices during motor tasks using functional imaging modalities. Several primate and human studies have suggested the formation of newly reorganized tracts in the ipsilesional or contralesional hemisphere, but the mechanism for the formation of these tracts is still largely unknown.

Methods: Three acute stroke patients who presented with abrupt deterioration of their right-sided hemiparesis due to the infarcts following a recurrent stroke in the originally unaffected hemisphere were studied using magnetic resonance imaging (MRI), MR angiography and single-photon emission CT.

Auditory and tactile processing in a postmeningitic deaf-blind patient with a cochlear implant.

The authors examined the neural function of a postmeningitic deaf-blind patient who regained his hearing with a multichannel cochlear implant. Auditory stimuli activated the temporal cortices of both sides in a manner similar to that of controls, reflecting the successful recruitment of the auditory cortex after implantation. The patient's occipital lobes were deactivated during the tactile language task, the results of which were completely different from those before cochlear implantation.

Brain processing of audiovisual sexual stimuli inducing penile erection: a positron emission tomography study.

Purpose: Penile erection is dependent on commands from the central nervous system. Although basic studies of animals and neuroimaging studies of humans have been conducted to identify key brain regions associated with sexual arousal, to our knowledge no reliable studies of the first excitation phase of sexual arousal leading to penile erection have been reported.

Materials And Methods: We used H(2)(15)O-positron emission tomography to analyze regional cerebral blood flow just before penile erection in heterosexual volunteers.

Neural mechanism of residual inhibition of tinnitus in cochlear implant users.

Residual inhibition is a transient suppression of tinnitus after auditory stimulation has stopped. We used positron emission tomography to study brain regions underlying residual inhibition in three tinnitus patients with cochlear implants and six normal hearing controls. Regional cerebral blood flow was measured and compared under two conditions: with tinnitus and during the residual inhibition of tinnitus.

Hemodynamic influences of losartan on the brain in hypertensive patients.

The effects of angiotensin II receptor blockers on cerebral hemodynamics in humans have not been well elucidated. The present study evaluated the effects of losartan on cerebral hemodynamics in hypertensive patients using positron emission tomography. Ten patients with essential hypertension (mean age, 60.

Clinical significance of cerebrovascular reserve in acetazolamide challenge -comparison with acetazolamide challenge H2O-PET and Gas-PET.

Objective: The response of cerebral blood flow (CBF) to acetazolamide (ACZ) challenge is frequently determined in clinical settings to evaluate cerebrovascular reserve (CVR). A reduced CVR can indicate patients with occlusive cerebrovascular disease and compromised hemodynamics who may be at increased risk of cerebral ischemia. However, how precisely ACZ reflects cerebral hemodynamic impairment remains obscure.

The effect of tapping finger and mode differences on cortical and subcortical activities: a PET study.

Using positron emission tomography (PET), the brain regions recruited for the tapping movement by different fingers and different tapping modes were investigated in ten young healthy volunteers without specific finger training. Auditory-paced (2 Hz) tapping movements were performed by the index (I) or ring (R) finger alone (single-finger tapping) and by the alternate use of the I and middle (M) fingers or the R and little (L) fingers (double-finger tapping). Each subject also provided subjective rankings of perceived task difficulty, as well as muscular fatigue, among the tapping tasks.

Spectral analysis of 99mTc-HMPAO for estimating cerebral blood flow: a comparison with H2(15)O PET.

Cerebral blood flow (CBF) can be quantified non-invasively using the brain perfusion index (BPI), which is determined using radionuclide angiographic data obtained through the use of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO). The BPI is generally calculated using graphical analysis (GA). In this study, BPI was measured using spectral analysis (SA), and the usefulness of SA was compared with that of GA.

Cerebral hemodynamics and metabolism in adult moyamoya disease: comparison of angiographic collateral circulation.

Purpose: The extent of the hemodynamic and metabolic impairments in adult patients with moyamoya disease is still controversial. The aim of the present study was to evaluate the hemodynamic and metabolic status in relation to the development of basal moyamoya vessels (BMVs).

Methods: The cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), oxygen extraction fraction (OEF), and cerebral blood volume (CBV) were measured using PET in ten patients with ischemic adult moyamoya disease (mean age, 36.

Extraction of arterial input function for measurement of brain perfusion index with 99mTc compounds using fuzzy clustering.

Cerebral blood flow (CBF) can be quantified non-invasively using the brain perfusion index (BPI) determined from radionuclide angiographic data generated with 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO). When measuring the BPI, manual drawing of regions of interest (ROIs) (manual ROI method) for the extraction of the arterial input function (AIF) can lead to serious individual differences. The purpose of this study was to apply the fuzzy c-means (FCM) clustering method to determine AIF, and to investigate its usefulness in comparison with the manual ROI method.

Cortical processing of tactile language in a postlingually deaf-blind subject.

We compared neural activation detected by magnetoencephalography (MEG) during tactile presentation of words and non-words in a postlingually deaf-blind subject and six normal volunteers. The left postcentral gyrus, bilateral inferior frontal gyri, left posterior temporal lobe, right anterior temporal lobe, bilateral middle occipital gyri were activated when tactile words were presented to the right hand of the deaf-blind subject. This set of activated regions was not observed in the normal volunteers, although activation of several combinations of these regions was detected.

Cerebral and cerebellar activation in power and precision grip movements: an H2 15O positron emission tomography study.

Most human manual grip movements can be divided into power gripping and precision gripping, but central neural control during these tasks remains unclear. We investigated activation of the whole brain to analyze how simple hand movements are performed. The cerebral blood flow of seven healthy right-handed volunteers was measured by H2 15O positron emission tomography during right grip tasks without gripping a target object.

Heterogeneity of cerebral blood flow in Alzheimer disease and vascular dementia.

Background And Purpose: Alzheimer disease (AD) and vascular dementia (VaD) are the two major diseases that cause dementia, and early diagnosis is important. Single photon emission CT (SPECT) of cerebral blood flow (CBF) is used for the early detection of dementia and as an auxiliary method for follow-up. AD shows reduced posterior blood flow and VaD manifests reduced anterior blood flow on CBF SPECT images.

Interobserver variability of cerebral blood flow measurements obtained using spectral analysis and technetium-99m labeled compounds.

Radionuclide angiography with technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or technetium-99m ethyl cysteinate dimer (99mTc-ECD) enables the non-invasive estimation of absolute cerebral blood flow (CBF) to be determined by using spectral analysis (SA). We previously demonstrated the clinical use of SA; however, this method involves a few manual steps. The aim of this study was to evaluate the interobserver variability of CBF estimations made using SA and compare these results with those obtained by using graphical analysis (GA).

Statistical image analysis of cerebral blood flow in vascular dementia with small-vessel disease.

Unlabelled: Small-vessel disease with dementia, which is the most frequent type of vascular dementia (VaD), often shows a cerebral blood flow (CBF) distribution with no obvious focal abnormalities and is therefore difficult to evaluate objectively. In this study, we combined CBF SPECT with 3-dimensional fractal analysis (3D-FA) to quantitatively assess the heterogeneity of CBF distribution and with 3-dimensional stereotactic surface projections (3D-SSP) to evaluate the distribution of CBF. We then evaluated the clinical validity of these techniques for the imaging diagnosis of VaD.