RESPONSE OF THE GREEK EARLY WARNING SYSTEM REUTER-STOKES IONIZATION CHAMBERS TO TERRESTRIAL AND COSMIC RADIATION EVALUATED IN COMPARISON WITH SPECTROSCOPIC DATA AND TIME SERIES ANALYSIS.

The Telemetric Early Warning System Network of the Greek Atomic Energy Commission consists mainly of a network of 24 Reuter-Stokes high-pressure ionization chambers (HPIC) for gamma dose rate measurements and covers all Greece. In the present work, the response of the Reuter-Stokes HPIC to terrestrial and cosmic radiation was evaluated in comparison with spectroscopic data obtained by in situ gamma spectrometry measurements with portable hyper pure Germanium detectors (HPGe), near the Reuter-Stokes detectors and time series analysis. For the HPIC detectors, a conversion factor for the measured absorbed dose rate in air (in nGy h-1) to the total ambient dose equivalent rate H*(10), due to terrestrial and cosmic component, was deduced by the field measurements. Time series analysis of the mean monthly dose rate (measured by the Reuter-Stokes detector in Thessaloniki, northern Greece, from 2001 to 2016) was performed with advanced statistical methods (Fast Fourier Analysis and Zhao Atlas Marks Transform). Fourier analysis reveals several periodicities (periodogram). The periodogram of the absorbed dose rate in air values was compared with the periodogram of the values measured for the same period (2001-16) and in the same location with a NaI (Tl) detector which in principle is not sensitive to cosmic radiation. The obtained results are presented and discussed.

In-hospital mortality risk of intertrochanteric hip fractures: a comprehensive review of the US Medicare database from 2005 to 2010.

PURPOSE: Intertrochanteric hip fracture is a common injury in the Medicare population. Very little is known about the in-hospital mortality risk of intertrochanteric hip fractures and associated demographics for the US Medicare population. The purpose of this study is to determine the in-hospital mortality rate of closed intertrochanteric hip fractures and to evaluate demographic factors influencing an increased mortality risk. METHODS: The PearlDiver Medicare database from 2005 to 2010 was queried for closed intertrochanteric hip fractures. Stratified sampling was conducted by creating subset for individuals with a death discharge from inpatient facilities. Statistical analysis was performed where appropriate. RESULTS: Throughout 2005-2010 there were a total of 1,138,142 intertrochanteric hip fractures. There were 19,385 deaths during the initial hospital stay, yielding a mortality rate of 1.70%. There was a 1.83% mortality rate for patients 75 and older and patients over the age of 84 comprised the majority of deaths at 58%. The mortality rate was lower for females (1.39%) than for males (2.56%) (p < 0.0002). CONCLUSION: We found in the Medicare database that there is a relatively low rate of in-hospitality mortality associated with intertrochanteric hip fractures; this rate is lower than previously reported. We report a 1.70% in-hospital mortality using a complete Medicare dataset. Based on previous reporting for short term and one-year mortality risk, the present study suggests that mortality risk is greatest after patients have been released from the hospital. More attention should be paid to understanding and attenuating the mortality associated with intertrochanteric hip fractures after the acute hospital phase.

Small retinal hemorrhages as the only sign of an intracranial aneurysm.

PURPOSE: To report a woman with two small circumpapillary and nerve fiber layer hemorrhages found on routine examination. METHODS: Case report. The patient had a history of severe headache 2 weeks previously but no other symptoms or signs. RESULT: Magnetic resonance imaging showed an intracranial aneurysm. CONCLUSIONS: This potentially lethal abnormality should be considered with small unexplained retinal hemorrhages, even when the neurologic examination is normal. A history of recent headache should be sought.

Functional magnetic resonance imaging: a potential tool for the evaluation of spinal cord stimulation: technical case report.

OBJECTIVE AND IMPORTANCE: The management of chronic pain of spinal origin continues to represent a challenge for neurosurgeons. Spinal cord stimulation for chronic intractable pain is an effective therapy in approximately 50% of patients. The present study uses a novel imaging approach, functional magnetic resonance imaging (fMRI), to examine the central effects of spinal cord stimulation. CLINICAL PRESENTATION: Three patients, each with a chronic history of intractable pain, were treated at the Toronto Hospital with a trial of dorsal column stimulation (DCS). For all patients, significant improvement in pain symptoms was achieved with DCS. INTERVENTION: fMRI on a 1.5-T conventional magnetic resonance system was used to study the effects of DCS in these patients. Images were collected while the stimulator was activated and deactivated. CONCLUSION: This report is the first to describe the cerebral effects of exogenous spinal cord stimulation with fMRI. fMRI allows for the objective examination of the effects of DCS and may provide an objective means of evaluating the efficacy of DCS as a therapy for intractable pain of spinal origin.

Combined utility of functional MRI, cortical mapping, and frameless stereotaxy in the resection of lesions in eloquent areas of brain in children.

We studied 16 children with lesions in the eloquent brain to determine if the amalgamation of information from functional magnetic resonance imaging (fMRI), frameless stereotaxy, and direct cortical mapping and recording could facilitate the excision of these lesions while minimizing potential neurological deficits. The mean age of the children was 10 years. Fourteen children presented with seizures. All lesions were located in or near eloquent cerebral cortex. fMRI was successful in all patients in delineating the relationship between the lesion and regions of task-activated cortex. The ISG wand was utilized in all cases for scalp and bone flap placement, and for intraoperative localization of the lesion. Direct cortical stimulation or recording of phase reversals with somatosensory evoked potentials helped delineate the central sulcus and language cortex in patients with lesions near the motor or language cortex. Intraoperative electrocorticography (ECoG) was utilized in all patients who presented with seizures to guide the extent of resection of the epileptiform cortex. Ten children had benign cerebral neoplasms, nine of which were totally resected. The other diagnoses included vascular malformations, Sturge-Weber, tuberous sclerosis, Rasmussen's encephalitis, and primitive neuroectodermal tumor. Only 1 patient with a left Rolandic AVM developed a new neurological deficit postoperatively. Thirteen of fourteen patients who presented with seizure disorders were rendered either seizure free or improved in terms of seizure control postoperatively. Follow-up has ranged from 12 to 18 months, with a mean follow-up of 15 months. We conclude that the techniques of fMRI, frameless stereotaxy, direct cortical stimulation and recording can be utilized in sequence to accurately localize intracerebral lesions in eloquent brain, and to reduce the morbidity of resecting these lesions in children.

Functional MRI of lateral occipitotemporal cortex during pursuit and motion perception.

We performed functional imaging with a conventional 1.5-T magnetic resonance scanner in 9 normal subjects. We used a gradient-echo technique to examine changes in signal between periods when subjects viewed a stationary black-and-white grating, a moving grating, and when they followed a moving spot. We located image pixels with significant differences between the viewing conditions. In 7 subjects, these occurred in the lateral occipitotemporal cortex, a region previously identified as a putative human homologue of the motion-sensitive middle temporal area (MT, or V5) of monkeys. Signal intensity was greater during pursuit of the moving dot than during viewing of the moving grating with the eyes still, despite the fact that the moving grating generated more retinal image motion. In contrast, signal intensity in striate cortex was least during pursuit of the moving dot. These findings suggest that the lateral occipitotemporal cortex has extraretinal signals during pursuit. Such signals may include attentional input, corollary eye movement information, or even a pursuit command. Extraretinal signals suggest that the lateral occipitotemporal cortex may contain a human homologue not only of MT but also of other components of the monkey V5 complex, such as the medial superior temporal area.