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Background The brain functional correlates of autobiographical recall are well established, but have been little studied in schizophrenia. Additionally, autobiographical memory is one of a small number of cognitive tasks that activates rather than de-activates the default mode network, which has been found to be dysfunctional in this disorder. Methods Twenty-seven schizophrenic patients and 30 healthy controls underwent functional magnetic resonance imaging while viewing cue words that evoked autobiographical memories. Control conditions included both non-memory-evoking cues and a low level baseline (cross fixation). Results Compared to both non-memory evoking cues and low level baseline, autobiographical recall was associated with activation in default mode network regions in the controls including the medial frontal cortex, the posterior cingulate cortex and the hippocampus, as well as other areas. Clusters of de-activation were seen outside the default mode network. There were no activation differences between the schizophrenic patients and the controls, but the patients showed clusters of failure of de-activation in non-default mode network regions. Conclusions According to this study, patients with schizophrenia show intact activation of the default mode network and other regions associated with recall of autobiographical memories. The finding of failure of de-activation outside the network suggests that schizophrenia may be associated with a general difficulty in de-activation rather than dysfunction of the default mode network per se.

Aims P2Y12 antagonists are the standard in antiplatelet therapy but their potential effects on functional myocardial recovery and cardioprotection post-myocardial infarction (MI) are unknown. We investigated in a preclinical model of MI whether ticagrelor and clopidogrel differently affect cardiac repair post-MI. Methods and results Pigs either received: (i) clopidogrel (600 mg; 75 mg/qd); (ii) ticagrelor (180 mg; 90 mg/bid); and (iii) placebo control. MI was induced by mid-left anterior descending coronary artery balloon occlusion (60 min) and animals received the maintenance doses for the following 42 days. Serial cardiac magnetic resonance was performed at Day 3 and Day 42 for the assessment of global and regional cardiac parameters. We determined cardiac AMP-activated protein kinase (AMPK), Akt/PKB, aquaporin-4, vascular density, and fibrosis. In comparison to controls, both P2Y12 antagonists limited infarct expansion at Day 3, although ticagrelor induced a further 5% reduction (P

We thank Drs Downey and Cohen and Dr Fernandez-Jimenez et al for their comments and interest on our article, 1 where we demonstrate in pigs and by 3T-cardiac magnetic resonance (CMR) analysis that ticagrelor protects against myocardial injury to a greater extent than clopidogrel. It is important to note that we report for the first time that ticagrelor cardioprotective effects are associated with the attenuation in myocardial edema formation after myocardial infarction (MI) through adenosine-related mechanisms. Drs Downey and Cohen have made major contributions to our understanding on the role of antiplatelet agents in cardioprotection by carrying out studies in rabbits and rodents.2,3 In this regard, the discrepancies found between their studies2,3 and Ye et al4 and ours may rely on species-related differences and methodological approaches used. It is worth mentioning that the same group which published the Ye et al4 paper has demonstrated, in contrast with Dr Downey and Cohen’s findings,2,3 that ticagrelor but not clopidogrel …

Background: The P2Y 12 receptor antagonist ticagrelor has been shown to be clinically superior to clopidogrel. Although the underlying mechanisms remain elusive, ticagrelor may exert off-target effects through adenosine-related mechanisms. We aimed to investigate whether ticagrelor reduces myocardial injury to a greater extent than clopidogrel after myocardial infarction (MI) at a similar level of platelet inhibition and to determine the underlying mechanisms. Methods: Pigs received the following before MI induction: (1) placebo-control; (2) a loading dose of clopidogrel (600 mg); (3) a loading dose of ticagrelor (180 mg); or (4) a loading dose of ticagrelor followed by an adenosine A1/A2-receptor antagonist [8-( p -sulfophenyl)theophylline, 4 mg/kg intravenous] to determine the potential contribution of adenosine in ticagrelor-related cardioprotection. Animals received the corresponding maintenance doses of the antiplatelet agents during the following 24 hours and underwent 3T-cardiac MRI analysis. Platelet inhibition was monitored by ADP-induced platelet aggregation. In the myocardium, we assessed the expression and activation of proteins known to modulate edema formation, including aquaporin-4 and AMP-activated protein kinase and its downstream effectors CD36 and endothelial nitric oxide synthase and cyclooxygenase-2 activity. Results: Clopidogrel and ticagrelor exerted a high and consistent antiplatelet effect (68.2% and 62.2% of platelet inhibition, respectively, on challenge with 20 μmol/L ADP) that persisted up to 24 hours post-MI ( P P =0.0026), an effect supported by troponin-I assessment and histopathologic analysis ( P =0.0021). Furthermore, in comparison with clopidogrel, ticagrelor significantly diminished myocardial edema by 24.5% ( P =0.004), which correlated with infarct mass ( r =0.73; P p -Sulfophenyl)theophylline administration abolished the cardioprotective effects of ticagrelor over clopidogrel. At a molecular level, aquaporin-4 expression decreased and the expression and activation of AMP-activated protein kinase signaling and cyclooxygenase-2 increased in the ischemic myocardium of ticagrelor- versus clopidogrel-treated animals ( P p -sulfophenyl)theophylline. Conclusions: Ticagrelor, beyond its antiplatelet efficacy, exerts cardioprotective effects by reducing necrotic injury and edema formation via adenosine-dependent mechanisms.

Resumen Fundamento y objetivo Los sindromes de deficiencia cerebral de creatina (Cr) constituyen un grupo de enfermedades neurometabolicas caracterizadas por deficiencia o ausencia de Cr en el cerebro. Cursan con retraso del desarrollo/mental y trastornos del lenguaje, y puede asociarse a epilepsia o a trastornos del movimiento. Se conocen 3 defectos: 2 de la sintesis —deficiencia de guanidinoacetato metiltransferasa (GAMT) y argininaglicina amidinotransferasa (AGAT)— y uno del transporte (CRTR). En este trabajo presentamos los 3 primeros pacientes espanoles con deficiencia de GAMT y comparamos su fenotipo clinico y respuesta al tratamiento con otros casos publicados. Pacientes y metodo Los pacientes presentan retraso mental, epilepsia y conducta autista. La paciente 1 asocia corea grave. El diagnostico se realizo mediante estudios bioquimicos para cuantificar metabolitos especificos y actividad enzimatica y geneticos del gen GAMT. Resultados En orina y plasma se detecto aumento de guanidinoacetato. La resonancia magnetica con espectroscopia revelo reduccion marcada de Cr cerebral. Los estudios enzimaticos mostraron disminucion de la actividad GAMT en fibroblastos y el estudio molecular revelo mutaciones en el gen GAMT. Tras el diagnostico, se inicio tratamiento con suplemento de Cr, y se asocio en los pacientes 2 y 3 una dieta restringida en arginina y suplemento de ornitina, con mejoria parcial. Conclusiones Los pacientes con deficiencia de GAMT presentan un fenotipo inespecifico pero relativamente constante. Deben buscarse los sindromes de deficiencia cerebral de Cr en pacientes con retraso mental/psicomotor de etiologia desconocida, especialmente si se acompanan de trastornos del movimiento y epilepsia. Es importante el diagnostico precoz en casos tratables como la deficiencia de GAMT.

Epidemiological studies have consistently reported that high-density lipoprotein (HDL) cholesterol levels are inversely associated with the risk of cardiovascular disease (CVD) [(1)][1]. In fact, plasma-derived and synthetic HDL, and/or its derivatives, have been shown to exert various

Recent studies have shown that MRS can substantially improve the non-invasive categorization of human brain tumours. However, in order for MRS to be used routinely by clinicians, it will be necessary to develop reliable automated classification methods that can be fully validated. This paper is in two parts: the first part reviews the progress that has been made towards this goal, together with the problems that are involved in the design of automated methods to process and classify the spectra. The second part describes the development of a simple prototype system for classifying H-1 single voxel spectra, obtained at an echo time (TE) of 135 ms, of the four most common types of brain tumour (meningioma (MM), astrocytic (AST), oligodendroglioma (OD) and metastasis (ME)) and cysts. This system was developed in two stages: firstly, an initial database of spectra was used to develop a prototype classifier, based on a linear discriminant analysis (LDA) of selected data points. Secondly, this classifier was tested on an independent test set of 15 newly acquired spectra, and the system was refined on the basis of these results. The system correctly classified all the non-astrocytic tumours. However, the results for the the astrocytic group were poorer (between 55 and 100%, depending on the binary comparison). Approximately 50% of high grade astrocytoma (glioblastoma) spectra in our data base showed very little lipid signal, which may account for the poorer results for this class. Consequently, far the refined system, the astrocytomas were subdivided into two subgroups for comparison against other tumour classes: those with high lipid content and those without

In patients with chronic hepatic encephalopathy, proton magnetic resonance spectroscopy can be used to detect specific metabolic abnormalities in the brain; MRI shows a hyperintense globus pallidus on T1-weighted sequences. We investigated the relationship between these two MR findings in a series of 25 patients with the use of quantitative data and a multiple regression analysis model. The cerebral increase in glutamine compounds and the decrease in myoinositol and choline correlated separately with globus pallidus hyperintensity, and each was complementary in accounting for this imaging finding. Such as association suggests that spectroscopic and imaging alterations are two different expressions of the reversible events that occur in the brain of patients with hepatic encephalopathy in that both disappear after liver transplantation. Globus pallidus hyperintensity seems to be a global indicator of the cerebral metabolic disorder, and the spectroscopic pattern denotes the specific metabolic alterations.

1. The potential risk of brain damage when low-landers attempt to climb the highest summits is a well-known fact. However, very little is known about what occurs to Himalayan natives, perfectly adapted to high altitude, when performing the same type of activity. 2. Taking into account their long-life climbing experience at extreme altitudes, we examined seven of the most recognized Sherpas with the aim of performing a comprehensive neurological evaluation based on medical history, physical examination and magnetic resonance brain imaging. We compared them with one group of 21 lowland elite climbers who had ascended to altitudes of over 8000 m, and another control group of 21 healthy individuals who had never been exposed to high altitude. 3. While all of the lowland climbers presented psychoneurological symptoms during or after the expeditions, and 13 of them (61%) showed magnetic resonance abnormalities (signs of mild cortical atrophy and/or periventricular high-intensity signal areas in the white matter), only one Sherpa (14%) showed similar changes in the scans, presenting neurological symptoms at extreme altitude. The neurological examination was normal in all three groups, and no neuroimaging abnormalities were detected in the control group. 4. The significant differences, in both clinical and neuroimaging terms, suggest that Sherpa highlanders have better brain protection when exposed to extreme altitude. Although the key to protection against cerebral hypoxia cannot be established, it is possible that an increase in the usually short period of acclimatization could minimize brain damage in those low-landers who attempt the highest summits without supplementary oxygen.

We studied the effects on CSF dynamics at the foramen magnum and the clinical significance of the abnormal tonsillar motion in 14 patients with Chiari type I malformation and 14 control subjects using cine phase-contrast MRI. Dynamic MRI consisted of axial and sagittal cine phase-contrast sequences. CSF and tonsillar motion were qualitatively and quantitatively evaluated, and the subarachnoid space at the foramen magnum measured. In Chiari patients, cine phase-contrast MRI detected the abnormal pulsatile motion of the cerebellar tonsils, which produced a selective obstruction of CSF flow from the cranial cavity to the spine. The amplitude of the tonsillar pulsation and the severity of the arachnoid space reduction were associated with the symptom of cough-strain headache, but not with the presence of syringomyelia. The finding of abnormal valve dynamics of the cerebellar hernia revealed by cine phase-contrast MRI conforms to the pathophysiologic mechanisms suggested in pressure register studies and opens a new possibility in the presurgical assessment of Chiari patients with exertional symptoms.

Object: This study demonstrates that 3T SV-MRS data can be used with the currently available automatic brain tumour diagnostic classifiers which were trained on databases of 1.5T spectra. This will allow the existing large databases of 1.5T MRS data to be used for diagnostic classification of 3T spectra, and perhaps also the combination of 1.5T and 3T databases. Materials and methods: Brain tumour classifiers trained with 154 1.5T spectra to discriminate among high grade malignant tumours and common grade II glial tumours were evaluated with a subsequently-acquired set of 155 1.5T and 37 3T spectra. A similarity study between spectra and main brain tumour metabolite ratios for both field strengths (1.5T and 3T) was also performed. Results: Our results showed that classifiers trained with 1.5T samples had similar accuracy for both test datasets (0.87 ± 0.03 for 1.5T and 0.88 ± 0.03 for 3.0T). Moreover, non-significant differences were observed with most metabolite ratios and spectral patterns. Conclusion: These results encourage the use of existing classifiers based on 1.5T datasets for diagnosis with 3T 1H SV-MRS. The large 1.5T databases compiled throughout many years and the prediction models based on 1.5T acquisitions can therefore continue to be used with data from the new 3T instruments. © 2011 ESMRMB., We would like to thank Miriam Camison-Sanchez for help in the quality control of the MRS data and diagnosis validation. This work was partially funded by the European Commission (FP6-2002-LIFESCIHEALTH 503094) and (IST-2004-27214), the I + D support program of the Universitat Politecnica de Valencia and by the Health Institute Carlos III through the RETICS Combiomed, RD07/0067/2001. CIBER-BBN is an initiative funded by the VI National R&D&D&I Plan 2008-2011, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. The authors acknowledge to Programa Torres Quevedo from Ministerio de Educacion y Ciencia, co-founded by the European Social Fund (PTQ05-02-03386, PTQ-08-01-06802, PTQ-08-01-06817).

Using magnetic resonance imaging, we studied 24 patients with ischemic infarction of the internal capsule. Magnetic resonance imaging detected wallerian degeneration of the pyramidal tract below the capsular lesion in 11 patients (45.8%); all 11 had clinical evidence of pyramidal tract damage. In six additional patients magnetic resonance imaging findings, present only on axial slices, were considered to indicate possible wallerian degeneration. When motor deficit was associated with posterior limb lesions, magnetic resonance imaging detected wallerian degeneration of the pyramidal tract in 78.6% (11) of 14 patients.

Contains fulltext : 50008.pdf (Publisher’s version ) (Closed access) A computer-based decision support system to assist radiologists in diagnosing and grading brain tumours has been developed by the multi-centre INTERPRET project. Spectra from a database of 1H single-voxel spectra of different types of brain tumours, acquired in vivo from 334 patients at four different centres, are clustered according to their pathology, using automated pattern recognition techniques and the results are presented as a two-dimensional scatterplot using an intuitive graphical user interface (GUI). Formal quality control procedures were performed to standardize the performance of the instruments and check each spectrum, and teams of expert neuroradiologists, neurosurgeons, neurologists and neuropathologists clinically validated each case. The prototype decision support system (DSS) successfully classified 89% of the cases in an independent test set of 91 cases of the most frequent tumour types (meningiomas, low-grade gliomas and high-grade malignant tumours--glioblastomas and metastases). It also helps to resolve diagnostic difficulty in borderline cases. When the prototype was tested by radiologists and other clinicians it was favourably received. Results of the preliminary clinical analysis of the added value of using the DSS for brain tumour diagnosis with MRS showed a small but significant improvement over MRI used alone. In the comparison of individual pathologies, PNETs were significantly better diagnosed with the DSS than with MRI alone.

OBJECTIVE: We sought to evaluate whether taurine detection in short-echo (20 ms) proton magnetic resonance spectroscopy contributes to the noninvasive differential diagnosis between medulloblastoma and cerebellar astrocytoma in children and young adults. These two types of tumor have very different prognoses and may be difficult to differentiate by neuroradiological or clinical means. METHODS: Single-voxel proton magnetic resonance spectra of tumors were acquired at 1.5 T in 14 patients with biopsy-proven primary cerebellar tumors (six medulloblastomas, seven astrocytomas, and one mixed astroependymoma) using short-echo time (20 ms) and long-echo time (135 ms). For taurine assignment, qualitative analysis was performed on short-echo time spectra and results were compared in vitro with spectra of model solutions. Perchloric acid extracts of postsurgical tumor biopsies were performed in two medulloblastoma cases. RESULTS: Taurine detection was demonstrated in all patients with medulloblastoma and in none of those with astrocytoma. We were unable to ascertain any relationship between taurine and metastatic spread within the medulloblastoma group. CONCLUSION: Medulloblastomas characteristically seem to show taurine detectable in vivo by short-echo proton magnetic resonance spectroscopy, which may help to discriminate medulloblastoma from cerebellar astrocytoma.

Pattern recognition techniques (factor analysis and neural networks) were used to investigate and classify human brain tumors based on the 1H NMR spectra of chemically extracted biopsies (n = 118). After removing information from lactate (because of variable ischemia times), unsupervised learning suggested that the spectra separated naturally into two groups: meningiomas and other tumors. Principal component analysis reduced the dimensionality of the data. A back-propagation neural network using the first 30 principal components gave 85% correct classification of meningiomas and nonmeningiomas. Simplification by vector rotation gave vectors that could be assigned to various metabolites, making it possible to use or to reject their information for neural network classification. Using scores calculated from the four rotated vectors due to creatine and glutamine gave the best classification into meningiomas and nonmeningiomas (89% correct). Classification of gliomas (n = 47) gave 62% correct within one grade. Only inositol showed a significant correlation with glioma grade., The authors thank Karen Elise Jensens Fond, Denmark; CICYT SAF93-0582-C02-01 and SAF96-0147, Spain: UK-Spain Concerted Action HB94-258: Xarxes Tematiques CIRIT (XT94-47), Spain; Conselleria de Sanitat, Generalitat de Catalunya, Spain; Cancer Research Campaign, UK; EC Concerted Action Biomed-1 PL920432; DGICYT PM92011 and PM94011, Spain; Neurosurgery Services at participating hospitals in Barcelona and Madrid, Spain: and SeRMN at Universitat Autónoma de Barcelona, Spain.

✓ The ability of functional magnetic resonance (MR) imaging to detect a selective sensorimotor cortex activation in healthy subjects and the feasibility of motor activation in patients with lesions around the central sulcus were investigated. Twenty-five healthy volunteers performed 100 motor activation trials, using a variety of motor tasks, which were monitored by several image analysis methods. The functional images were obtained using a 1.5-tesla standard MR imaging system magnet with blood oxygenation level—dependent contrast. Four patients were assessed using functional MR imaging and invasive cortical mapping. Rolandic cortex activation was observed in 98% of the trials performed on healthy subjects in which no head motion occurred. Nevertheless, the cortical response was not selective in a task-rest analysis due to concurrent activation of neighboring regions. Across-task comparison analyses were useful in canceling nonrelevant activity in most cases (86%). In the patient group, the region identified as the sensorimotor cortex by invasive means corresponded accurately to the area that was activated in functional MR imaging. Present data support the feasibility of detecting selective activation of the rolandic cortex, even in the clinical setting, leading the authors to suggest the usefulness of this widely available technique in surgical planning.

In cirrhotic patients, even in the non-encephalopathic state, MRI may show an increased signal in globus pallidus in T1-weighted sequences, the clinical significance of which is still poorly characterized. A dysfunction of the motor circuit of the basal ganglia might be predicted if the increased MRI signal expressed alterations in the globus pallidus activity. We compared the Bereitschaftspotential (BP) in 15 non-encephalopathic cirrhotic patients and 15 age-matched controls and found that the amplitude of the early component and the peak negativity of the BP before the electromyogram onset were significantly reduced in the patient group. The intensity of the pallidal signal was related to the plasma ammonia level but the amplitudes of the BP were not related to the pallidal signal or to ammonia. These findings indicate that a defective activity of the cortical areas implicated in the preparation of movement, not specifically related to the pallidal signal, can be present in cirrhotic patients, even in the non-encephalopathic state.

Article abstract—We investigated the long-term persistence and short-term stability of globus pallidus (GP) hyperintensity on T1--weighted MRI in 19 cirrhotic patients. After a mean interval of 25.8 months, the hyperintensity of the GP persisted in 17 patients. Hyperintensity disappeared in two patients with hepatocarcinoma, indicating that hyperintensity can revert to normal in circumstances other than liver transplants. Ten patients participated in a 6–month study with repeated evaluations of GP signal intensity, plasma ammonia levels, and selected neuropsychological tests. The GP signal was fairly stable during the follow-up, and the variables considered maintained significant relationships. GP hyperintensity appears as a stable indicator of the functional status of cirrhotic patients.

The aim of the present study was to look for anatomical changes in climbers' brains, using magnetic resonance imaging (MRI), after extremely high-altitude climbs and to relate them to possible associated risk factors. Clinical history, neurological examinations and MRI were carried out on a group of nine climbers before and after climbing to over 7500 m without the use of supplementary oxygen. None of the subjects showed any neurological dysfunctions. In five climbers MRI abnormalities (high signal areas, cortical atrophy) were observed before the expedition. After the descent, two of them showed new high intensity signal areas recorded by MRI. Both subjects suffered severe neurological symptoms during the climb. The present study suggested that the brain changes observed by MRI could be related to the severity of clinical events at high altitude. However, we do not know the exact meaning of such MRI findings or the reason for their location, predominantly in posterior regions of the brain. The new evidence that a high percentage of climbers show MRI brain abnormalities, and especially the appearance of changes after the ascent, reinforces the possibility of a potential neurological risk in high-altitude climbing.

Introduccion. Las infecciones del sistema nervioso central (SNC) en pediatria se asocian a una gran morbimortalidad. La neuroimagen desempena un papel cada vez mas importante en la deteccion precoz de complicaciones neurologicas. Objetivo. Describir los hallazgos encontrados en las secuencias de difusion (DWI) y su posible utilidad en el diagnostico precoz y el pronostico de las secuelas neurologicas. Pacientes y metodos. Es un estudio descriptivo retrospectivo de una serie de 23 pacientes, con edades comprendidas entre 1 mes y 16 anos, afectos de infeccion del SNC, a los que se realizo resonancia magnetica (RM). Resultados. La clasificacion etiologica fue la siguiente: 13 casos de meningoencefalitis virica y 10 casos de meningitis bacteriana. La RM se realizo entre el primer y septimo dia de ingreso. Encontramos lesion del SNC en RM convencional o DWI en 14 de 23 casos (60%). En tres pacientes, la lesion neurologica (infarto cortical aislado) solo fue evidente en la DWI. Encontramos algun tipo de secuela neurologica en 17 de 21 casos. La secuela neurologica identificada con mayor frecuencia fue la epilepsia (9 de 21). Al relacionar las secuelas con los hallazgos en RM y con la DWI, vimos una mayor tendencia a encontrar secuelas mas graves cuando existen hallazgos patologicos en la neuroimagen, con una relacion que no es estadisticamente significativa. Conclusiones. Las DWI pueden ser utiles en el diagnostico precoz de complicaciones neurologicas en las infecciones del SNC.

In 1982 Gouti6res and Aicardi ~ described three patients with a syndrome characterized by (1) an abrupt clinical onset after an infectious illness, (2) impaired consciousness, axial hypotonia, motor rigidity, and abnormal movements and postures, (3) sustained improvement of neurologic status, and (4) bilateral low-density lesions of the basal ganglia on the computed tomographie scan. Three similar patients also have been repor ted) 4 It is likely that some other patients described before the advent of modern neuroimaging techniques had this same syndrome) Huntington chorea, Wilson disease, Hallervorden-Spatz syndrome, mitochondrial eneephalomyopathies including Leigh syndrome, familial striatal necrosis, head trauma, hypoxia-ischemia, and various intoxications can occur in childhood with acute or subaeute neurologie dysfunction associated with bilateral low-density lesions in the basal ganglia. The outcome of all of them, however, is poorer than that of acute neurologic dysfunction associated with destructive lesions of the basal ganglia, as described by Gouti6res and Aicardi. 1 We describe two patients with A D B G who had a complete clinical recovery. The CT scan findings in the acute phase of the disease were identical in both patients and supported the diagnosis. Bilateral, symmetric, necrotic lesions of the basal ganglia were found in the magnetic resonance imaging studies from the early stages of the disease and persisted in our second patient up to 5 years later.

✓ Two cases of brain abscess were diagnosed by combining magnetic resonance spectroscopy (MRS) and magnetic resonance (MR) imaging. The resonances observed in vivo were assigned by means of an in vitro MRS study of the exudates extracted during surgical aspiration of the abscesses. The technique of MRS was demonstrated to be very powerful in the differential diagnosis of brain abscesses from other brain pathologies such as neoplasms. Amino acids, probably originating from extracellular proteolysis, and other compounds, such as acetate, arising from bacterial metabolism, were visible in the MRS spectra of the abscess, whereas they are not present in spectra of neoplasms. In this sense, MRS complemented the information provided by MR imaging to achieve a correct diagnosis of brain abscesses and could be added to routine MR examinations with only a small increase in cost and time.

In cirrhotic patients, even in a stable nonencephalopathic state, MRI may show cerebral atrophy and increased signal in globus pallidus on T1-weighted sequences. We investigated the relationship between cerebral atrophy and increased pallidal signal and the clinical status of 30 cirrhotic patients. We found a weak association between the two MRI findings. There were different patterns of clinical variables related to the imaging findings. Performance on motor tasks involving speed correlated with the pallidal signal and plasma ammonia levels but not with atrophy. Test results for memory and frontal-premotor function were associated with brain atrophy but not with the pallidal signal or with ammonia.

Background Although there are undeniable diagnostic benefits of CT scanning, its increasing use in paediatric radiology has become a topic of concern regarding patient radioprotection. Objective To assess the rate of CT scanning in Catalonia, Spain, among patients younger than 21 years old at the scan time. Materials and methods This is a sub-study of a larger international cohort study (EPI-CT, the International pediatric CT scan study). Data were retrieved from the radiological information systems (RIS) of eight hospitals in Catalonia since the implementation of digital registration (between 1991 and 2010) until 2013. Results The absolute number of CT scans annually increased 4.5% between 1991 and 2013, which was less accentuated when RIS was implemented in most hospitals. Because the population attending the hospitals also increased, however, the rate of scanned patients changed little (8.3 to 9.4 per 1,000 population). The proportions of patients with more than one CT and more than three CTs showed a 1.51- and 2.7-fold increase, respectively, over the 23 years. Conclusion Gradual increases in numbers of examinations and scanned patients were observed in Catalonia, potentially explained by new CT scanning indications and increases in the availability of scanners, the number of scans per patient and the size of the attended population. Supported in part by the Seventh Framework Programme from the European Community (Grant agreement no: 269912) and the Consejo de Seguridad Nuclear.

Object. The authors sought to evaluate the advantages and limitations of functional magnetic resonance (fMR) imaging when it was used regularly in the clinical context to identify the central sulcus. Methods. A 1.5-tesla MR system comprising a spoiled gradient recalled acquisition in the steady-state functional sequence and a cross-hand cancellation analysis method were used to evaluate 50 surgical candidates with centrally located space-occupying lesions in the brain. Three-dimensional (3-D) models of the patient's head and brain showing the relative position of the tumor and the eloquent cortex were obtained in each case. A selective and reproducible focal activation was found, indicating the probable central sulcus position in 41 patients (82%). Direct cortical stimulation confirmed the fMR findings in 100% of 22 intraoperatively assessed patients. Failure to identify the central sulcus occurred in 18% of cases and was mainly a consequence of intrinsic damage in the primary sensorimotor region that resulted in severe hand paresis. Conclusions. Although specific factors were identified that contributed to reduced sensitivity of fMR imaging in the clinical context, the present study supports functional assessment and 3-D representation of specific surgical situations as generally feasible in common practice.

Object. Hemangiopericytomas are a rare type of brain tumor that are very similar to meningiomas in appearance and symptoms but require different treatment. It is not normally possible to distinguish between them by using magnetic resonance (MR) imaging and computerized tomography studies. However, discrimination may be possible by using in vivo MR spectroscopy (MRS) because the biochemical composition of these two lesions is different. The goal of this study was to describe the use of MRS in discriminating between these similar tumor types. Methods. In vivo MRS spectra were acquired in 27 patients (three with hemangiopericytomas and 24 with meningiomas) by using a single-voxel proton brain examination system at 1.5 teslas with short— (20-msec) and long— (135-msec) echo times. In addition, brain biopsy specimens obtained by open craniotomy were frozen within 5 minutes of resection and stored in liquid nitrogen until they were used. The specimens were powdered, extracted with perchloric acid, redissolved in 2H2O, and high-resolution in vitro MRS was used at 9.4 teslas to record their spectra. Conclusions. In this study the authors show that hemangiopericytomas could be clearly distinguished from meningiomas because they have a larger peak at 3.56 ppm. Measurements of extracts of the tumors and comparison of spectra acquired with MRS at long— (135-msec) and short— (20-msec) echo times established that this was due to the much higher levels of myoinositol in the hemangiopericytomas.