As a sequel of brain ischemia, selective neuronal loss (SNL)—as opposed to pannecrosis (i.e. infarction)—is attracting growing interest, particularly because it is now detectable in vivo. In acute stroke, SNL may affect the salvaged penumbra and hamper functional recovery following reperfusion. Rodent occlusion models can generate SNL predominantly in the striatum or cortex, showing that it can affect behavior for weeks despite normal magnetic resonance imaging. In humans, SNL in the salvaged penumbra has been documented in vivo mainly using positron emission tomography and 11C-flumazenil, a neuronal tracer validated against immunohistochemistry in rodent stroke models. Cortical SNL has also been documented using this approach in chronic carotid disease in association with misery perfusion and behavioral deficits, suggesting that it can result from chronic or unstable hemodynamic compromise. Given these consequences, SNL may constitute a novel therapeutic target. Selective neuronal loss may also develop a...

https://journals.sagepub.com/doi/pdf/10.1038/jcbfm.2013.188

Selective Neuronal Loss in Ischemic Stroke and Cerebrovascular Disease

Traumatic brain injury (TBI) affects an estimated 1.7 million people in the United States and is a contributing factor to one third of all injury related deaths annually. According to the CDC, approximately 75% of all reported TBIs are concussions or considered mild in form, although the number of unreported mild TBIs and patients not seeking medical attention is unknown. Currently, classification of mild TBI (mTBI) or concussion is a clinical assessment since diagnostic imaging is typically inconclusive due to subtle, obscure, or absent changes in anatomical or physiological parameters measured using standard magnetic resonance (MR) or computed tomography (CT) imaging protocols. Molecular imaging techniques that examine functional processes within the brain, such as measurement of glucose uptake and metabolism using [18F]fluorodeoxyglucose and positron emission tomography (FDG-PET), have the ability to detect changes after mild TBI. Recent technological improvements in the resolution of PET systems, the integration of PET with MRI, and the availability of normal healthy human databases and commercial image analysis software contribute to the growing use of molecular imaging in basic science research and advances in clinical imaging. This review will discuss the technological considerations and limitations of FDG-PET, including differentiation between glucose uptake and glucose metabolism and the significance of these measurements. In addition, the current state of FDG-PET imaging in assessing mild TBI in clinical and preclinical research will be considered. Finally, this review will provide insight into potential critical data elements and recommended standardization to improve the application of FDG-PET to mild TBI research and clinical practice.

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FDG-PET imaging in mild traumatic brain injury: a critical review

Perioperative stroke is associated with considerable morbidity and mortality. Stroke recognition and diagnosis are challenging perioperatively, and surgical patients receive therapeutic interventions less frequently compared with stroke patients in the outpatient setting. These updated guidelines from the Society for Neuroscience in Anesthesiology and Critical Care provide evidence-based recommendations regarding perioperative care of patients at high risk for stroke. Recommended areas for future investigation are also proposed.

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Perioperative care of patients at high risk for stroke during or after non-cardiac, non-neurologic surgery: consensus statement from the Society for Neuroscience in Anesthesiology and Critical Care*.

The purposes of this study are to establish oxygen extraction fraction (OEF) measurements using quantitative susceptibility mapping (QSM) of magnetic resonance imaging (MRI), and to compare QSM–OEF data with the gold standard 15O positron emission tomography (PET). Twenty-six patients with chronic unilateral internal carotid artery or middle cerebral artery stenosis or occlusion, and 15 normal subjects were included. MRI scans were conducted using a 3.0 Tesla scanner with a three-dimensional spoiled gradient recalled sequence. QSM images were created using the morphology-enabled dipole inversion method, and OEF maps were generated from QSM images using extraction of venous susceptibility induced by deoxygenated hemoglobin. Significant correlation of relative OEF ratio to contra-lateral hemisphere between QSM–OEF and PET–OEF was observed (r = 0.62, p < 0.001). The local (intra-section) correlation was also significant (r = 0.52, p < 0.001) in patients with increased PET–OEF. The sensitivity and specificity...

https://journals.sagepub.com/doi/pdf/10.1177/0271678X15606713

Oxygen extraction fraction measurement using quantitative susceptibility mapping: Comparison with positron emission tomography:

Expanding the concept of neuroprotection for acute ischemic stroke: The pivotal roles of reperfusion and the collateral circulation.

Studies in the 1990s demonstrated that misery perfusion is a predictor of subsequent stroke in medically treated patients with symptomatic major cerebral artery disease. A recent randomized controlled trial demonstrated no benefit of bypass surgery for such patients. In this light, outcome in patients with misery perfusion has regained interest. The purpose of this study was to determine whether misery perfusion is still a predictor of subsequent stroke despite recent improvements in medical treatment for secondary prevention of stroke, and if so, whether the predictive value of misery perfusion has changed in recent years. We prospectively studied 165 non-disabled patients with symptomatic atherosclerotic internal carotid artery or middle cerebral artery occlusive diseases who underwent positron emission tomography from 1999 to 2008. Misery perfusion was defined as decreased cerebral blood flow, increased oxygen extraction fraction and decreased ratio of cerebral blood flow to blood volume in the hemisphere supplied by the diseased artery. All patients were followed up for 2 years until stroke recurrence or death. Bypass surgery was performed in 19 of 35 patients with and 16 of 130 patients without misery perfusion. The 2-year incidence of ipsilateral ischaemic stroke was six and four patients with and without misery perfusion, including two and one after surgery, respectively ( P  < 0.002). Total strokes occurred in nine patients with misery perfusion and 12 patients without ( P  < 0.01). The relative risk conferred by misery perfusion in whole sample was 6.3 (95% confidence interval 1.7–22.4, P  < 0.005) for ipsilateral ischaemic stroke and 3.5 (95% confidence interval 1.4–8.9, P  < 0.01) for all strokes, while the respective values in medically treated patients were 12.6 (95% confidence interval 2.7–57.8, P  < 0.005) and 4.7 (95% confidence interval 1.3–16.3, P  < 0.02). The all-stroke incidence in patients entering the study from 2004 to 2008 (4/72) was significantly lower than in those entering from 1999 to 2003 (17/93; P  < 0.02), although the prevalence of misery perfusion or bypass surgery did not differ. Between these periods, patients without misery perfusion demonstrated a decrease in stroke rate (from 16.2% to 0%), but patients with misery perfusion did not (26.3 and 25.0%). In symptomatic major cerebral artery disease, misery perfusion remains a predictor of subsequent stroke, although the recurrence rate was lower than the previous study. In patients without misery perfusion, the risk of stroke was reduced over time. Thus, identification and stricter management of patients with misery perfusion are essential to further improve prognosis.

* Abbreviations
 : EC/IC
 : extracranial to intracranial
 ICA
 : internal carotid artery
 MCA
 : middle cerebral artery
 OEF
 : oxygen extraction fraction

/pdf/is-misery-perfusion-still-a-predictor-of-stroke-in-3g7zwq24zs.pdf

Is misery perfusion still a predictor of stroke in symptomatic major cerebral artery disease

Purpose 18 F-FDG PET is used to investigate the metabolic activity of neural tissue. MRI is used to visualize morphological changes, but the relationship between intramedullary signal changes and clinical outcome remains controversial. The present study was designed to evaluate the use of 3-D MRI/ 18 F-FDG PET fusion imaging for defining intramedullary signal changes on MRI scans and local glucose metabolic rate measured on 18 F-FDG PET scans in relation to clinical

/pdf/of-the-spinal-cord-in-patients-with-cervical-compressive-39wlh2jl6p.pdf

of the spinal cord in patients with cervical compressive myelopathy

https://www.onlinecjc.ca/article/S0828-282X(11)01422-X/pdf

Cardiac Involvement of Adult T-Cell Leukemia/Lymphoma

OBJECTIVE: The purpose of this study was to evaluate the appropriate parameters of a filter and of subsets (S) and iterations (I) of the ordered-subset expectation maximization (OSEM) algorithm in 11C-acetate PET METHODS: A Hanning filter (HF) and a Gaussian filter (GF) were selected for filtered back-projection (FBP) and the OSEM algorithm, respectively After evaluation of the optimal HF size, the GF size was optimized using healthy volunteers (HV) Myocardial blood flow (MBF) and oxygen consumption (k(mono)) values were calculated by combining 4S, 16S, or 28S with 2I, 4I, 6I, or 8I of the OSEM (MBF(OSEM) and k(monoOSEM), respectively) in eight HV and eight coronary artery disease (CAD) patients These MBF(OSEM) and k(monoOSEM) values were compared with those obtained using FBP (MBF(FBP) and k(monoFBP), respectively) RESULTS: Optimal HF and GF (100GF) sizes for the FBP and OSEM algorithms, respectively, were 100 mm full-width resolution at half-maximum MBF(OSEM) was changed by modifying the parameters of the OSEM algorithm The best correlations were between MBF(FBP) and MBF(OSEM), with 28S6I and 100GF for HV patients and 28S8I for CAD patients However, the MBF(OSEM) with 28S8I was significantly different from MBF(FBP) at the global myocardium in HV The k(monoOSEM) with 28S6I was not significantly different from k(monoFBP) in HV or CAD patients CONCLUSION: Appropriate parameters are 28S6I with a 100GF on the MBF(OSEM) and k(monoOSEM) measurement using 11C-acetate Diagnostic performance will improve using noiseless, artifact-reduction images, and accurate quantitative values that are provided by the OSEM algorithm with the appropriate parameters

/pdf/appropriate-parameters-of-the-ordered-subset-expectation-gt4qtk9rav.pdf

Appropriate parameters of the ordered-subset expectation maximization algorithm on measurement of myocardial blood flow and oxygen consumption with 11C-acetate PET.

The tumor suppressor gene p53 plays an important role in determining radiosensitivity. The normal p53 gene product accumulates after exposure to ionizing radiation, and causes growth arrest or promotes cell death through the apoptosis pathway (Figure 1). Mutation of the p53 gene is the most common genetic alteration observed in human cancers (Nigro et al. 1989). It has been widely reported that cells with mutant p53 are more resistant to ionizing radiation or DNA-damaging agents (Fan et al. 1994; Wattel et al. 1994; Lee et al. 1993; Hamada et al. 1996). On the other hand, there have been reports of cells harboring mutant p53 that are sensitive to ionizing radiation and anticancer drugs (Biard et al. 1994; Fan et al.

/pdf/radiation-sensitivity-and-transcription-profiles-in-various-3vk0nfx447.pdf

Takashi Kudo

Papers

Is misery perfusion still a predictor of stroke in symptomatic major cerebral artery disease

of the spinal cord in patients with cervical compressive myelopathy

Cardiac Involvement of Adult T-Cell Leukemia/Lymphoma

Appropriate parameters of the ordered-subset expectation maximization algorithm on measurement of myocardial blood flow and oxygen consumption with 11C-acetate PET.

Radiation-Sensitivity and Transcription Profiles in Various Mutant p53 Cells