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Background Up to now there is little evidence about the safety and reliability of insertable cardiac monitors (ICMs) in patients undergoing magnetic resonance imaging (MRI). Objective The purpose of this prospective single-center study (MACPAF; clinicaltrials.gov NCT01061931), which we are currently performing, was to evaluate these issues for the ICM Reveal XT at a 3 Tesla MRI scanner in patients undergoing serial brain MRI. Methods We present an interim analysis including 62 brain MRI examinations in 24 patients with paroxysmal atrial fibrillation bearing the Reveal XT. All patients were interviewed for potential ICM-associated clinical symptoms during and after MRI examination. According to the study protocol, data from the Reveal XT were transmitted before and after the MRI examination. Results All patients were clinically asymptomatic during the MRI procedure. Moreover, the reliability (ability to detect signals, battery status) of the Reveal XT was unaffected, except for one MRI-induced artifact that was recorded by the ICM, mimicking a narrow complex tachycardia, as similarly recorded in a further study patient bearing the forerunner ICM Reveal DX. No loss of ICM data was observed after the MRI examination. Conclusions The 3 Tesla brain MRI scanning is safe for patients bearing the ICM Reveal XT and does not alloy reliability of the Reveal XT itself. MRI-induced artifacts occur rarely but have to be taken into account.

Eleven patients had no initial vessel occlusion, 19 showed re-canalization at 1–6 h (early recanalizers), and 6 additional patients showed recanalization at 24 h (late recanalizers). Four patients were nonrecanalizers. Age, gender and time to treatment did not differ between the subgroups. At baseline, nonrecanalizers had significantly larger perfusion deficits (p = 0.011) and patients with no initial occlusion had significantly smaller DWI and hypoperfu-sion volumes. Median lesion growth until 1–6 h was not signifi-cantly different between the groups (p = 0.167). The median lesion growth from baseline until 24 h was significantly larger in the nonrecanalizers compared to the other groups (71.4 vs. 2.8 ml, p < 0.05). The median perfusion deficit at 24 h and final lesion size did not differ between early and late recanalizers; both were sig-nificantly larger in nonrecanalizers. A modified Rankin Scale score of 0–2 at 3 months was reached by 66% of the recanalizers while no nonrecanalizer reached an independent outcome (p = 0.02).

Hyperintense signal within the subarachnoid space (SAS), visualized on delayed postcontrast fluid-attenuated inversion recovery (FLAIR) in MRI, is proposed to be caused by early blood–brain barrier (BBB) breakdown due to ischemia,1 and must be differentiated from subarachnoid hemorrhage. Reperfusion is the strongest independent predictor of early BBB disruption following ischemia and the phenomenon is described as hyperintense acute reperfusion marker (HARM).2 We present a case of hyperintense signal …

Importance The effectiveness of intravenous thrombolysis in acute ischemic stroke is time dependent. The effects are likely to be highest if the time from symptom onset to treatment is within 60 minutes, termed the golden hour . Objective To determine the achievable rate of golden hour thrombolysis in prehospital care and its effect on outcome. Design, Setting, and Participants The prospective controlled Prehospital Acute Neurological Treatment and Optimization of Medical Care in Stroke study was conducted in Berlin, Germany, within an established infrastructure for stroke care. Weeks were randomized according to the availability of a specialized ambulance (stroke emergency mobile unit (STEMO) from May 1, 2011, through January 31, 2013. We included 6182 consecutive adult patients for whom a stroke dispatch (44.1% male; mean [SD] age, 73.9 [15.0] years) or regular care (45.0% male; mean [SD] age, 74.2 [14.9] years) were included. Interventions The STEMO was deployed when the dispatchers suspected an acute stroke during emergency calls. If STEMO was not available (during control weeks, when the unit was already in operation, or during maintenance), patients received conventional care. The STEMO is equipped with a computed tomographic scanner plus a point-of-care laboratory and telemedicine connection. The unit is staffed with a neurologist trained in emergency medicine, a paramedic, and a technician. Thrombolysis was started in STEMO if a stroke was confirmed and no contraindication was found. Main Outcomes and Measures Rates of golden hour thrombolysis, 7- and 90-day mortality, secondary intracerebral hemorrhage, and discharge home. Results Thrombolysis rates in ischemic stroke were 200 of 614 patients (32.6%) when STEMO was deployed and 330 of 1497 patients (22.0%) when conventional care was administered ( P P P = .21 and 0.69 [95% CI, 0.32-1.53]; P = .36) and were more likely to be discharged home (adjusted odds ratio, 1.93 [95% CI, 1.09-3.41]; P = .02). Conclusions and Relevance The use of STEMO increases the percentage of patients receiving thrombolysis within the golden hour. Golden hour thrombolysis entails no risk to the patients’ safety and is associated with better short-term outcomes. Trial Registration clinicaltrials.gov Identifier:NCT01382862

Cortical signal intensity changes due to brief (1 s) innocuous electrical stimuli applied to the second and fifth finger of the right hand were measured by means of fMRI at 1.5 T. The activation pattern in this event-related fMRI approach closely resembled that obtained in recent block-design studies. Activations were found in contralateral primary (SI) and bilaterally in secondary (SII) somato-sensory cortex as well as in posterior parietal cortex, insula, and supplementary motor area (SMA). In SI, the somatotopic organization of the hand area is demonstrated, more clearly to be seen in area 3b than in area 1 and 2. In conclusion, the feasibility to employ event-related somatosensory stimulation paradigms in fMRI studies is demonstrated.

This fMRI study investigated the human somatosensory system, especially the secondary somatosensory cortex (SII), with respect to its potential somatotopic organization. Eight subjects received electrical stimulation on their right second finger, fifth finger and hallux. Within SII, the typical finding for both fingers was a representation site within the contralateral parietal operculum roughly halfway between the lip of the lateral sulcus and its fundus, whereas the representation site of the hallux was found more medially to this position at the fundus of the lateral sulcus, near the posterior pole of the insula. Somatotopy in SII seems to be less fine-grained than in primary somatosensory cortex (SI), as, in contrast to SI, no separate representations of the two fingers in SII were observed. A similar somatotopic representation pattern between fingers and the hallux was also observed within ipsilateral SII, indicating somatotopy of contra- as well as ipsilateral SII using unilateral stimulation. Further areas exhibiting activation were found in the superior and inferior parietal lobule, in the supplementary and cingulate motor area, and in the insula.

In this study 16 unilateral upper extremity amputees participated in a comprehensive psychophysiological examination that included the assessment of painful and non-painful phantom and stump sensations, thermal and electric perception as well as two-point discrimination thresholds, the detailed analysis of referred sensation and the measurement of reorganizational changes in primary somatosensory cortex using neuroelectric source imaging. Reorganization of the primary somatosensory cortex was associated with increased habitual phantom limb pain, telescoping, non-painful stump sensations and painful referred sensation induced by painful stimulation. It was unrelated to non-painful phantom sensations, non-painful referred sensation elicited by painful or non-painful stimulation, painful referred sensation elicited by non-painful stimulation, perception thresholds and stump pain. These data substantiate the hypothesis that painful and non-painful phantom phenomena are mediated by different neural substrates.

Using electrical finger nerve stimulation in normal human subjects, fMRI detected separate representations for all 5 fingers in the primary somatosensory cortex. Responses were located in the posterior wall of the deep central sulcus (most likely corresponding to Brodmann Area (BA) 3b), and the anterior (BA 1) or posterior crown of the postcentral gyrus (BA 2) with rare activations in BA 3a and 4. In BA 3b we found a regular somatotopic mediolateral digit arrangement for fingers 5 to 1 with a mean Euclidean distance of 16 mm between fingers 1 and 5. In contrast BA 1/2 showed a greater number of adjacent activation foci with significantly more overlap and partly even reversed ordering of neighbouring fingers.

Objective: Assessment of the effectiveness of constraint-induced (CI) movement therapy and quantitative evaluation of the effects of CI therapy. Design: Intervention study; case series; pretreatment to posttreatment measures and follow-up 3 months after intervention. Setting: An outpatient department. Patients: Five chronic stroke patients with moderate motor deficit; convenience sample. Interventions: CI therapy consisting of restraint of the unaffected upper extremity in a sling for 14 days combined with 6 hours of training per weekday of the affected upper extremity. Main Outcome Measures: Actual Amount of Use Test (AAUT), Motor Activity Log (MAL), Wolf Motor Function Test (WMFT), and Arm Motor Ability Test (AMAT) Results: There was a substantial improvement in the performance times of the laboratory tests (AMAT, WMFT, p ≤ .039) and in the quality of movement (AMAT, WMFT, p ≤ .049; MAL, p = .049), particularly in the use of the extremity in "real world" environments (AAUT, p = .020), supported by results of quantitative evaluation. The effect sizes were large and comparable to those found in previous studies of CI therapy. Conclusions: CI therapy is an efficacious treatment for chronic stroke patients, especially in terms of real world outcome.

FUNCTIONAL magnetic resonance imaging (fMRI) is capable of detecting focal brain activation induced by electrical stimulation of single fingers in human subjects. In eight subjects somatotopic arrangement of the second and fifth finger was found in Brodmann area 3b of the primary somatosensory cortex. In four subjects the representation area of the second finger was located lateral and inferior to the fifth finger; in one subject the somatotopy was reversed. In three subjects representation areas of the two fingers in Brodmann area 3b were found overlapping. Additional activated areas were found on the crown of ipsilateral and contralateral post-central gyrus (Brodmann areas 1 and 2) and posterior parietal cortex.

We used near-infrared spectroscopy (NIRS) to study non-invasively changes in cerebral hemoglobin oxygenation in the frontal and parietal cortex during performance of a verbal fluency task in patients with Alzheimer's disease (AD). Whereas healthy elderly subjects (n = 19, age 67 +/- 10 years) showed increases in concentrations of oxygenated hemoglobin [HbO2] (mean (arbitrary units) +/- S.E.M., 1.44 +/- 0.59) and total hemoglobin [HbT] (0.92 +/- 0.81) over the left superior parietal cortex, patients with AD (n = 19, age 71 +/- 10 years) showed significant decreases in [HbO2] (-3.26 +/- 1.30, P < 0.01) as well as [HbT] (-4.45 +/- 1.57, P < 0.01). [HbR] decreased slightly in both groups (-0.62 +/- 0.29 and - 1.18 +/- 0.40, respectively). Using two pairs of NIRS optodes placed on the left superior partietal cortex and on the left prefrontal cortex simultaneous increases in [HbO2] as well as [HbT] in both cortical regions in the healthy elderly subjects (n = 8, age 60 +/- 15) were demonstrated during performance of the task. AD patients (n = 10, age 65 +/- 13 years) showed decreases in [HbO2] and [HbT] in the parietal cortex and, at the same time, increases in [HbO2] and [HbT] in the frontal cortex. Simultaneous NIRS-[HbT] and PET-rCBF measurements showed a significant correlation both when calculated in a 'banana' shaped volume approximated by using cortical thresholds as well as when calculated in a semisphere volume of brain tissue beneath the optodes placed on the head surface (patients with AD, n = 10). The correlation was dependent on the assumed penetration depth of the near-infrared light and was best for all three NIRS variables ([HbO2], [HbR] and [HbT]) when calculated using a semisphere radius of 0.45 cm to 1.35 cm. In conclusion, in Alzheimer's disease a marked reduction of regional cerebral blood flow and cerebral hemoglobin oxygenation may occur during activation of brain function, probably mainly in degenerating brain areas, such as the parietal cortex.

It has been shown that near-infrared spectroscopy (NIRS) permits the assessment of functional brain activation.8,9,14,21 Four studies were dedicated to the visual system which partly yielded conflicting results.10,11,13,21 Though all studies showed an increase in [oxy-Hb] during visual stimulation using different stimulation paradigms, the changes observed in [deoxy-Hb] were not uniform. Meek et al.13 reported on a decrease in [deoxy-Hb] in 4 of 10 subjects but an increase in the other 6 subjects, while Kato et al.11 and Hoshi et al.10 using photic stimulation of 8 Hz and 10 Hz found an increase in [deoxy-Hb] in their studies. On the other hand, Villringer et al.21 observed a decrease in [deoxy-Hb] during photic stimulation and picture observation, but this included only 3 subjects lacking therefore statistical evaluation. All NIRS-investigators10,11,13,21 localised the optical probes only with respect to external bony landmarks without knowledge of the exact spatial relation of these landmarks to the anatomy of the brain. This could have led to inaccurate positions of the optical probes over the visual cortex as there is a great variability of the calcarine fissure concerning these external landmarks.18 Localising the optical probes individually according to previously acquired 3D MRI, the aim of the current study was to investigate whether there is a consistent, statistically evident pattern of changes in [oxy-Hb] and [deoxy-Hb] during visual stimulation. Furthermore, we investigated if NIRS is able to detect oxygenation changes due to activation of a secondary or prestriate visual area known from studies both in monkeys and humans as area V5 or MT to be sensitive to the submodality “visual motion”.12,19,22,24

Present implementations of near infrared spectroscopy permit the detection of signals related to neuronal activity non-invasively through the intact skull (for review see: Chance, 1991). Due to the limited penetration of photons in soft tissue that is in the range of a few centimeters (Chance et al., 1993), the NIRS field of view is restricted to the outer cerebral cortex in the human adult (Villringer K et al., this issue). Activation-induced changes in regional cerebral endogenous chromophore concentrations (oxygenated [HbO2] and reduced [HbR] hemoglobin, as well as total hemoglobin [HbT]) have been demonstrated during the performance of either cognitive tasks (Hoshi et al., 1993a; Villringer et al., 1993) or visual (Kato et al., 1993) and motor stimulation (Obrig et al., 1996). As cognitive disturbances occur in a variety of psychiatric disorders, such as dementia, depression, schizophrenia and substance abuse, NIRS may help to detect disease- or syndrome-specific alterations that may be either of diagnostic value and/or useful for therapeutic monitoring. So far, activation-induced changes in NIRS variables have been demonstrated during normal aging (Hock et al., 1995a), dementia (Hock et al., 1995b) and schizophrenia (Okada et al., 1994). However, in view of the powerful neuroimaging methods such as magnetic resonance imaging (MRI), functional MRI (fMRI) and positron emission tomography (PET), one has to ask for the specific advantages of the NIRS method, that is in the adult, so far, only in experimental use. Although at the moment inferior to PET with regard to spatial as well as to fMRI with regard to spatial and temporal resolution, NIRS has an interesting potential: the method requires neither large expensive equipment nor an exogenous contrast medium, unlike PET or MRI.

Neuronal activation is coupled to localised changes in regional cerebral blood flow, blood oxygenation and metabolism (Leninger-Follert et al. 1979, Frostig et al. 1990). On this basis it is possible to detect and localise activated brain areas by the use of functional imaging methods like PET and fMRI (Phelps et al. 1985, Fox et al. 1986, Belliveau et al. 1991). The high spatial resolution of these imaging methods allows to characterise and localise hemodynamic and metabolic changes of activated brain areas on an anatomical basis. Near infrared spectroscopy noninvasively detects changes in the concentration of oxy-Hb, deoxy-Hb and Cyt-O2 by measuring changes in absorption at specific wavelength of light in the near infrared region. The technique in the first instance was used to detect global changes in cerebral hemodynamics (Jobsis 1977, Elwell 1994) and was recently introduced to assess hemodynamic response induced by functional brain activation (Hoshi et al. 1993, Villringer et al. 1993, Obrig et al. 1995, Kato et al. 1993, Meek et al. 1995), The high temporal resolution and the ability to assess several oxygenation parameters simultaneously provides information about temporal dynamics of oxygenation changes in response to functional stimulation. Reasons for using this technique to investigate functional brain activation lie in some advantages compared to traditionally used functional imaging methods. Near infrared spectroscopy is completely non-invasive low expensive and can be used with high flexibility. NIRS allows repeated measures and administration of exogenous tracers is not required. The technique is therefore suited for assessment of brain function in clinical settings as a bedside technique.

A tissue database was established by using multidimensional clusters of exact longitudinal (T1) and transversal (T2) relaxation times and spin density, allowing the automatic segmentation and characterization of healthy and pathologic tissue. All parameters were simultaneously acquired employing a modified Multi-Echo pulse sequence. Initial clinical results showed a good differentiation between normal brain tissue and pathologic tissue like edema and meningioma. Inhomogeneous tumors such as high-grade glioblastoma were difficult to characterize automatically. The implementation of a diffusion-weighted modified Tanner-Stejskal pulse sequence allows the acquisition of the Apparent Diffusion Constant (ADC), which has been incorporated for the first time into a multidimensional information set as a new tissue-characterizing parameter. This parameter is sensitive to changes in the mobility of water in and between different cell compartments resulting from metabolic cell disorders like ischemic or edematous processes. To reproduce the known results of animal experiments, where as early as 30 min after an ischemic event the measurement of the ADC led to a diagnosis, diffusion-weighted imaging had to be implemented on a standard clinical scanner. The correction of unavoidable motion artifacts, which occur when applying diffusion- weighted spin echo sequences on standard clinical scanners, require the implementation of a special sequence using the navigator echo method followed by a correction algorithm of the raw data in Fourier space. Initial results showed a significant improvement in the differentiation of healthy and pathologic tissue classes.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We examined local changes of cerebral oxygenation in response to visual stimuli by means of near infrared spectroscopy. A sharply outlined colored moving stimulus which is expected to evoke a broad activation of the striate and prestriate cortex was presented to sixteen healthy subjects. Six of these subjects were also exposed to a colored stationary and a gray stationary stimulus. In two subjects the colored moving stimulus was tested against the colored stationary with an optode position presumably over area V5/MT. As a control condition, subjects performed a simple finger opposition task. Since the calcarine fissure varies greatly with respect to bony landmarks, optodes were positioned individually according to 3-D reconstructed magnetic resonance imaging (MRI). Concentration changes in oxyhemoglobin ([oxy-Hb]) and deoxyhemoglobin ([deoxy-Hb]) were continuously monitored with a temporal resolution of 1 s, using an NIRO 500 (Hamamatsu Photonics, KK, Japan). In response to the visual stimulus, the grand average across all sixteen subjects resulted in a significant increase in [oxy-Hb] of 0.3360.09 arbitrary units (mean6S.E.M.) mirrored by a significant decrease in [deoxy-Hb] of −0.1860.02 arbitrary units, while the motor control condition elicited no significant changes in any parameters. When the near infrared spectroscopy probes were positioned over area V5/MT, the drop of [deoxy-Hb] associated with the moving stimulus was significantly more pronounced than with the stationary stimulus in both subjects examined. No significant differences between the visual stimuli were observed at the optode position close to the calcarine fissure. The oxygenation changes observed in this study are consistent with the pattern we have reported for motor activation. They are in line with physiological considerations and functional MRI studies relying on blood oxygenation level-dependent contrast.

We applied non-invasive multisite near-infrared spectroscopy (NIRS) to assess oxygenation changes during performance of a sequential finger opposition task in five healthy human adults. Oxygenation response was localized anatomically using three-dimensional high-resolution magnetic resonance imaging (3D MRI). NIRS measurements showed a localized increase in [oxy-Hb] and a decrease in [deoxy-Hb] in all subjects. The largest response was obtained when the measurement position was over the primary motor and sensory cortex hand area. Interestingly, changes in [deoxy-Hb] seemed to be more localized than changes in [oxy-Hb]. We conclude that this simple, non-invasive and flexible optical bedside method may be used for functional brain mapping.