Fat infiltration and muscle hydration improve after high-intensity resistance training in women with sarcopenia. A randomized clinical trial.

BACKGROUND: Resistance training is recommended for preventing sarcopenia, but the benefits for the quality and quantity of muscle mass are uncertain. OBJECTIVE: To assess the effects of high-intensity resistance training (HIRT) on clinical and magnetic resonance imaging (MRI) parameters in women with sarcopenia. METHODS: A researcher-blinded randomized clinical trial was conducted. Community-dwelling older women with sarcopenia were randomized to six months of HIRT or a control group (CG). Body composition was assessed with bioimpedance equipment, and participants underwent strength and functional performance tests (short physical performance battery [SPPB] and gait speed). MRI scans of the thigh were taken to quantify muscle mass and quality. RESULTS: Thirty-eight women completed the study (20 in the HIRT group). Sarcopenia remitted in 50 % of the HIRT group. HIRT elicited a significant group × time interaction effect for muscle mass (p = 0.027; È 2 = 0.129), muscle mass index (p = 0.023; È 2 = 0.135), fat mass (p = 0.048; È 2 = 0.103) and all strength variables (p < 0.05; È 2 > 0.120). Moreover, the HIRT group obtained higher scores on the SPPB (mean difference [MD] 1.2; p = 0.005) and the 5 times sit-to-stand test (MD = 0.7; p = 0.009). Regarding MRI parameters, infiltrated microscopic fat decreased significantly (HIRT: MD = -0.01; p < 0.05), while hydration (T2) decreased in the CG (MD = 3.6 ms; p = 0.053) at six months. There were significant between-group differences at six months for water diffusion (HIRT: 1.09 × 10-3 mm2/s vs CG: 1.26 × 10-3 mm2/s) and total muscular volume (HIRT: 832.4 L vs CG: 649.2 L). CONCLUSIONS: HIRT led to the remission of sarcopenia in half of the older women, as seen in muscle mass, strength, and functional performance and MRI biomarkers, with significant increases in muscle quality. REGISTERED IN CLINICALTRIALS.GOV: NCT03834558.

FOXP2 expression and gray matter density in the male brains of patients with schizophrenia.

Common genetic variants of FOXP2 may contribute to schizophrenia vulnerability, but controversial results have been reported for this proposal. Here we evaluated the potential impact of the common FOXP2 rs2396753 polymorphism in schizophrenia. It was previously reported to be part of a risk haplotype for this disease and to have significant effects on gray matter concentration in the patients. We undertook the first examination into whether rs2396753 affects the brain expression of FOXP2 and a replication study of earlier neuroimaging findings of the influence of this genetic variant on brain structure. FOXP2 expression levels were measured in postmortem prefrontal cortex samples of 84 male subjects (48 patients and 36 controls) from the CIBERSAM Brain and the Stanley Foundation Array Collections. High-resolution anatomical magnetic resonance imaging was performed on 79 male subjects (61 patients, 18 controls) using optimized voxel-based morphometry. We found differences in FOXP2 expression and brain morphometry depending on the rs2396753, relating low FOXP2 mRNA levels with reduction of gray matter density. We detected an interaction between rs2396753 and the clinical groups, showing that heterozygous patients for this polymorphism have gray matter density decrease and low FOXP2 expression comparing with the heterozygous controls. This study shows the importance of independent replication of neuroimaging genetic studies of FOXP2 as a candidate gene in schizophrenia. Furthermore, our results suggest that the FOXP2 rs2396753 affects mRNA levels, thus providing new knowledge about its significance as a potential susceptibility polymorphism in schizophrenia.

Effectiveness of the PROMUFRA program in pre-frail, community-dwelling older people: A randomized controlled trial.

This study evaluated the effect of PROMUFRA program on physical frailty, kinanthropometric, muscle function and functional performance variables in pre-frail, community-dwelling older people. Participants (n = 50, 75 ± 7 years) were randomly assigned to two groups: intervention group (IG), and control group (CG). The IG performed multi-component exercise program, focused on high-intensity resistance training (HIRT) combined with self-massage for myofascial release (SMMR) for 12 weeks (2 d.wk-1). Two measurements were performed, at baseline and post-3 months. Participants (n = 43) were analyzed and significant differences were found in group-time interaction for muscle mass (p = 0.017), fat mass (p = 0.003), skeletal muscle mass index (p = 0.011), maximum isometric knee extension (p = 0.042), maximum dynamic knee extension (p = 0.001), maximum leg press (p < 0.001), Barthel Index (p = 0.039) and EuroQol 5-dimensions-3-levels (p = 0.012). We conclude that PROMUFRA program is an effective training method to achieve healthy improvements for the pre-frail community.

The Role of Imaging Biomarkers in the Assessment of Sarcopenia.

BACKGROUND: The diagnosis of sarcopenia through clinical assessment has some limitations. The literature advises studies that include objective markers along with clinical assessment in order to improve the sensitivity and specificity of current diagnostic criteria. The decrease of muscle quality precedes the loss of quantity, so we studied the role magnetic resonance imaging biomarkers as indicators of the quantity and quality of muscle in sarcopenia patients. METHODS: a cross-sectional analysis was performed to analyze what MR-derived imaging parameters correlate better with sarcopenia diagnostic criteria in women of 70 years of age and over (independent walking and community-dwelling women who were sarcopenic in accordance with EWGSOP criteria with muscle mass adjusted to Spanish population were chosen). RESULTS: The study included 26 women; 81 ± 8 years old. A strong correlation was obtained between cineanthropometric variables (BMI; thigh perimeter and fat mass) and imaging biomarkers (muscle/fat ratio, fatty infiltration, muscle T2*, water diffusion coefficient, and proton density fat fraction) with coefficients around 0.7 (absolute value). CONCLUSIONS: Knowing the correlation of clinical parameters and imaging-derived muscle quality indicators can help to identify older women at risk of developing sarcopenia at an early stage. This may allow taking preventive actions to decrease disability, morbidity, and mortality in sarcopenia patients.

First-Episode Psychotic Patients Showed Longitudinal Brain Changes Using fMRI With an Emotional Auditory Paradigm.

Most previous longitudinal studies of functional magnetic resonance imaging (fMRI) in first-episode psychosis (FEP) using cognitive paradigm task found an increased activation after antipsychotic medications. We designed an emotional auditory paradigm to explore brain activation during emotional and nonemotional word processing. This study aimed to analyze if longitudinal changes in brain fMRI BOLD activation is present in patients vs. healthy controls. A group of FEP patients (n = 34) received clinical assessment and had a fMRI scan at baseline and follow-up (average, 25-month interval). During the fMRI scan, both emotional and nonemotional words were presented as a block design. Results were compared with a pair of healthy control group (n = 13). Patients showed a decreased activation at follow-up fMRI in amygdala (F = 4.69; p = 0.04) and hippocampus (F = 5.03; p = 0.03) compared with controls. Middle frontal gyrus was the only area that showed a substantial increased activation in patients (F = 4.53; p = 0.04). A great heterogeneity in individual activation patterns was also found. These results support the relevance of the type of paradigm in neuroimaging for psychosis. This is, as far as we know, the first longitudinal study with an emotional auditory paradigm in FEP. Our results suggested that the amygdala and hippocampus play a key role in psychotic disease. More studies are needed to understand the heterogeneity of response at individual level.

Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age.

Accurate age estimation in wildlife conservation is an important diagnostic tool in the interpretation of biological data, necropsy examination, reproductive status and population demographics. The most frequently utilized methods to age bottlenose dolphins (Tursiops truncatus) include tooth extraction; counting dental growth layer groups and dental radiography. These methods are inaccurate in dolphins > 13 years old, due to overlapping of the growth layer groups in dolphins and worn teeth. Establishing a non-invasive method of accurately aging bottlenose dolphins across the entire age range is important to long term conservation efforts to understand health status, lifespan, reproduction and survivability. A database of 126 radiographs from 94 dolphins of known chronological age was utilized to establish the stages of skeletal ossification over time. A numerical score from -1 to 8 was assigned to 16 anatomic locations on the pectoral radiograph, to create a formula to estimate age. The most informative areas to evaluate morphologically were the metaphyseal regions of the radius and ulna, and the proximal and distal epiphysis of metacarpals II and III. Third order polynomial regression calculated separate age predictor formulas for male and female dolphins, with females reaching sexual maturity earlier than males. Completion of epiphyseal closure of the long bones correlated with average sexual maturity. Managed care dolphin ages could be properly estimated with decreasing precision from within 3 months in animals < 5 years old, to within 5 years in animals > 30 years old. This diagnostic tool could also be applied to diagnose atypical ossification patterns consistent with nutritional, developmental or growth abnormalities, and identifying subclinical health issues. In conclusion, knowledge of the lifespan and the onset of sexual maturity for each species will allow this model to be applied to other cetaceans, facilitating age estimation via pectoral radiography in future research.

Auditory hallucinations in first-episode psychosis: A voxel-based morphometry study.

BACKGROUND: Auditory hallucinations (AH) are a core symptom of psychosis. The brain abnormalities responsible for AH remain controversial due to inconsistent and conflicting findings across studies, with substantial confounding factors, such as chronicity. Few studies have examined the pathological changes that occur in the gray matter (GM) of patients with first-episode psychosis (FEP) and AH. The present study aims to validate the presence and characteristics of these structural abnormalities in relation to the intensity of psychotic symptoms and AH in a larger homogeneous sample than those of previous studies. METHODS: A magnetic resonance voxel-based morphometric analysis was applied to a group of 215 patients with FEP (93 patients with AH and 122 patients without AH) and 177 healthy controls. The patients were evaluated using the PANSS scale. RESULTS: Patients with FEP exhibited greater reductions in GM concentrations in the temporal, frontal, cingulate and insular areas than the healthy controls did. No specific differences were found between the patients with FEP and AH and the patients without AH. In addition, total scores on the PANSS were negatively correlated with GM reductions in the FEP group. No correlations were found between the severity of the AH and the GM volumes. CONCLUSIONS: As in previous studies, reductions in the GM concentrations in patients with FEP suggest that alterations are present in the early stages of psychosis, and these alterations are correlated with the severity of the illness. The GM reductions were not found to be related to the presence or severity of AH.

Multi-parametric MR Imaging Biomarkers Associated to Clinical Outcomes in Gliomas: A Systematic Review.

PURPOSE: To systematically review evidence regarding the association of multiparametric biomarkers with clinical outcomes and their capacity to explain relevant subcompartments of gliomas. MATERIALS AND METHODS: Scopus database was searched for original journal papers from January 1st, 2007 to February 20th, 2017 according to PRISMA. Four hundred forty-nine abstracts of papers were reviewed and scored independently by two out of six authors. Based on those papers we analyzed associations between biomarkers, subcompartments within the tumor lesion, and clinical outcomes. From all the articles analyzed, the twenty-seven papers with the highest scores were highlighted to represent the evidence about MR imaging biomarkers associated with clinical outcomes. Similarly, eighteen studies defining subcompartments within the tumor region were also highlighted to represent the evidence of MR imaging biomarkers. Their reports were critically appraised according to the QUADAS-2 criteria. RESULTS: It has been demonstrated that multi-parametric biomarkers are prepared for surrogating diagnosis, grading, segmentation, overall survival, progression-free survival, recurrence, molecular profiling and response to treatment in gliomas. Quantifications and radiomics features obtained from morphological exams (T1, T2, FLAIR, T1c), PWI (including DSC and DCE), diffusion (DWI, DTI) and chemical shift imaging (CSI) are the preferred MR biomarkers associated to clinical outcomes. Subcompartments relative to the peritumoral region, invasion, infiltration, proliferation, mass effect and pseudo flush, relapse compartments, gross tumor volumes, and highrisk regions have been defined to characterize the heterogeneity. For the majority of pairwise cooccurrences, we found no evidence to assert that observed co-occurrences were significantly different from their expected co-occurrences (Binomial test with False Discovery Rate correction, α=0.05). The co-occurrence among terms in the studied papers was found to be driven by their individual prevalence and trends in the literature. CONCLUSION: Combinations of MR imaging biomarkers from morphological, PWI, DWI and CSI exams have demonstrated their capability to predict clinical outcomes in different management moments of gliomas. Whereas morphologic-derived compartments have been mostly studied during the last ten years, new multi-parametric MRI approaches have also been proposed to discover specific subcompartments of the tumors. MR biomarkers from those subcompartments show the local behavior within the heterogeneous tumor and may quantify the prognosis and response to treatment of gliomas.

Difference in Regional Brain Volume between Fibromyalgia Patients and Long-Term Meditators.

BACKGROUND: The practice of meditation has been shown to improve pain-related quality of life and also to alter brain activity. To assess brain volumetry in fibromyalgia (FM) patients, healthy meditators and healthy non-meditator control groups, and to elucidate the possible association between brain changes in meditators and years of meditation practice. METHODS: Twelve patients diagnosed with FM, eleven long-term Zen meditators and ten healthy control subjects closely matched for sex and age were recruited. A high resolution T1-3D sequence was acquired and a high-dimensional DARTEL normalization strategy was applied. Questionnaires on anxiety, depression and cognitive impairment were administered. RESULTS: There was a statistically significant increase in grey matter volume in the Brodmann area 20 (right and left inferior temporal gyri) in patients with fibromyalgia and a significant decrease in the meditator group as compared to controls. On the other hand, there was a significant increase in grey matter volume in fibromyalgia patients as compared to controls and meditators, to the right temporal gyrus (p=0.03, t=6.85) and left temporal gyrus (p=0.04, t=6.31). The number of months of meditation did not correlate with significant grey matter volume changes in the meditator group. CONCLUSIONS: FM and meditation appears to be reliably associated with altered anatomical structure in the Brodmann area 20 (in both inferior temporal gyri), and these changes are associated with anxiety and depression levels. In addition, exploratory morphometric analyses for fibromyalgia patients and meditators may reveal relevant brain regions showing structural diminution in meditation practitioners. Morphologic changes might predispose toward vulnerability to develop a chronic pain state. Such structural diminutions could potentially indicate functional benefits.

Diferencias en el volumen cerebral regional entre pacientes de fibromialgia y meditadores de larga duración / Difference in Regional Brain Volume between Fibromyalgia Patients and Long-Term Meditators

Contextualización teórica/antecedentes. La práctica de la meditación ha demostrado mejorar la calidad de vida en relación con el dolor padecido, así como alterar la actividad cerebral. Se evalúa la volumetría cerebral en pacientes de fibromialgia (FM), con grupos de control de meditadores y no-meditadores sanos, para dilucidar la posible asociación entre los cambios cerebrales en meditadores y los años de práctica de la meditación. Metodología. La muestra se compone de doce pacientes diagnosticados con FM, once meditadores Zen consolidados y diez sujetos control sanos clasificados por edad y sexo. Los sujetos se exploraron con una secuencia de Resonancia Magnética T1-3D de alta resolución y las imágenes se analizaron mediante una estrategia de normalización DARTEL (Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra) de alta dimensionalidad. Se administraron cuestionarios sobre ansiedad, depresión y deterioro cognitivo. Resultados. Se observó un incremento estadísticamente significativo en el volumen de la sustancia gris en el área 20 de Brodmann (giro inferior temporal derecho e izquierdo) en los pacientes con fibromialgia y una disminución significativa en el grupo de meditadores en comparación con el grupo control. Por otra parte, se observó un incremento significativo del volumen de sustancia gris en pacientes con fibromialgia en comparación con el grupo control y el grupo de meditadores en los giros temporales derechos (p=0.03, t=6.85) e izquierdos (p=0.04, t=6.31). El número de meses de práctica de la meditación no correlacionó con cambios significativos en el volumen de sustancia gris en el grupo de meditadores. Conclusiones. La fibromialgia y la meditación parecen estar asociadas de manera fiable con alteraciones anatómicas localizadas en el área 20 de Brodmann (giro inferior y temporal), estando a su vez estos cambios asociados con los niveles de ansiedad y depresión. Además, los análisis morfológicos exploratorios en los pacientes con fibromialgia y los meditadores, pueden revelar disminuciones estructurales relevantes en regiones cerebrales en los practicantes de meditación. Los cambios morfológicos podrían suponer una mayor predisposición al desarrollo de un estado de dolor crónico, mientras que tales disminuciones estructurales podrían indicar potenciales beneficios funcionales (AU)

Background. The practice of meditation has been shown to improve pain-related quality of life and also to alter brain activity. To assess brain volumetry in fibromyalgia (FM) patients, healthy meditators and healthy non-meditator control groups, and to elucidate the possible association between brain changes in meditators and years of meditation practice. Methods. Twelve patients diagnosed with FM, eleven long-term Zen meditators and ten healthy control subjects closely matched for sex and age were recruited. A high resolution T1-3D sequence was acquired and a high-dimensional DARTEL normalization strategy was applied. Questionnaires on anxiety, depression and cognitive impairment were administered. Results. There was a statistically significant increase in grey matter volume in the Brodmann area 20 (right and left inferior temporal gyri) in patients with fibromyalgia and a significant decrease in the meditator group as compared to controls. On the other hand, there was a significant increase in grey matter volume in fibromyalgia patients as compared to controls and meditators, to the right temporal gyrus (p=0.03, t=6.85) and left temporal gyrus (p=0.04, t=6.31). The number of months of meditation did not correlate with significant grey matter volume changes in the meditator group. Conclusions. FM and meditation appears to be reliably associated with altered anatomical structure in the Brodmann area 20 (in both inferior temporal gyri), and these changes are associated with anxiety and depression levels. In addition, exploratory morphometric analyses for fibromyalgia patients and meditators may reveal relevant brain regions showing structural diminution in meditation practitioners. Morphologic changes might predispose toward vulnerability to develop a chronic pain state. Such structural diminutions could potentially indicate functional benefits (AU)

Retinal structure assessed by OCT as a biomarker of brain development in children born small for gestational age.

PURPOSE: To identify differences in neuronal tissue from retinal and brain structures in children born small for gestational age (SGA) with no abnormality in neonatal brain ultrasonography and no previous neurological impairment, and to evaluate the relationship between retinal structure and brain changes in school-age children born SGA. METHODS: Two cohorts of children were recruited: 25 children born SGA and 25 children born with an appropriate birth weight according to gestational age. All the children underwent an ophthalmic examination, which included retinal imaging using spectral-domain optical coherence tomography, and a brain MRI. MRI images were automatically segmented and global and regional brain volumes were obtained. RESULTS: Although visual function did not differ between both groups, the complex ganglion cell and inner plexiform layers (GCL-IPL) was thinner in SGA children. Total intracranial volume, and global grey and white matter volumes in brain and cerebellum were correlated with birthweight centile, as were certain regional volumes (temporal and parietal lobes, hippocampus and putamen). Abnormal GCL-IPL measurements accurately identified SGA children with the most severe grey and white matter changes in the brain. CONCLUSIONS: SGA children, both preterm and term born, showed evidence of structural abnormalities in the retina, which may be an accurate and non-invasive biomarker of neuronal damage in brain tissue.

Magnetic resonance spectroscopy and brain volumetry in mild cognitive impairment. A prospective study.

OBJECTIVE: To assess the accuracy of magnetic resonance spectroscopy (1H-MRS) and brain volumetry in mild cognitive impairment (MCI) to predict conversion to probable Alzheimer's disease (AD). METHODS: Forty-eight patients fulfilling the criteria of amnestic MCI who underwent a conventional magnetic resonance imaging (MRI) followed by MRS, and T1-3D on 1.5 Tesla MR unit. At baseline the patients underwent neuropsychological examination. 1H-MRS of the brain was carried out by exploring the left medial occipital lobe and ventral posterior cingulated cortex (vPCC) using the LCModel software. A high resolution T1-3D sequence was acquired to carry out the volumetric measurement. A cortical and subcortical parcellation strategy was used to obtain the volumes of each area within the brain. The patients were followed up to detect conversion to probable AD. RESULTS: After a 3-year follow-up, 15 (31.2%) patients converted to AD. The myo-inositol in the occipital cortex and glutamate+glutamine (Glx) in the posterior cingulate cortex predicted conversion to probable AD at 46.1% sensitivity and 90.6% specificity. The positive predictive value was 66.7%, and the negative predictive value was 80.6%, with an overall cross-validated classification accuracy of 77.8%. The volume of the third ventricle, the total white matter and entorhinal cortex predict conversion to probable AD at 46.7% sensitivity and 90.9% specificity. The positive predictive value was 70%, and the negative predictive value was 78.9%, with an overall cross-validated classification accuracy of 77.1%. Combining volumetric measures in addition to the MRS measures the prediction to probable AD has a 38.5% sensitivity and 87.5% specificity, with a positive predictive value of 55.6%, a negative predictive value of 77.8% and an overall accuracy of 73.3%. CONCLUSION: Either MRS or brain volumetric measures are markers separately of cognitive decline and may serve as a noninvasive tool to monitor cognitive changes and progression to dementia in patients with amnestic MCI, but the results do not support the routine use in the clinical settings.

Post-treatment changes of tumour perfusion parameters can help to predict survival in patients with high-grade astrocytoma.

OBJECTIVES: Vascular characteristics of tumour and peritumoral volumes of high-grade gliomas change with treatment. This work evaluates the variations of T2*-weighted perfusion parameters as overall survival (OS) predictors. METHODS: Forty-five patients with histologically confirmed high-grade astrocytoma (8 grade III and 37 grade IV) were included. All patients underwent pre- and post-treatment T2*-weighted contrast-enhanced magnetic resonance (MR) imaging. Tumour, peritumoral and control volumes were segmented. Relative variations of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), Ktrans-T2*, kep-T2*, ve-T2* and vp-T2* were calculated. Differences regarding tumour grade and surgical resection extension were evaluated with ANOVA tests. For each parameter, two groups were defined by non-supervised clusterisation. Survival analysis were performed on these groups. RESULTS: For the tumour region, the 90th percentile increase or stagnation of CBV was associated with shorter survival, while a decrease related to longer survival (393 ± 189 vs 594 ± 294 days; log-rank p = 0.019; Cox hazard-ratio, 2.31; 95% confidence interval [CI], 1.12-4.74). Ktrans-T2* showed similar results (414 ± 177 vs 553 ± 312 days; log-rank p = 0.037; hazard-ratio, 2.19; 95% CI, 1.03-4.65). The peritumoral area values showed no relationship with OS. CONCLUSIONS: Post-treatment variations of the highest CBV and Ktrans-T2* values in the tumour volume are predictive factors of OS in patients with high-grade gliomas. KEY POINTS: • Vascular characteristics of high-grade glioma tumour and peritumoral regions change with treatment. • Quantitative assessment of MRI perfusion provides valuable information regarding tumour aggressiveness. • Quantitative T2*-weighted perfusion parameters can help to predict overall survival. • Post-treatment variations of CBV and K trans-T2 values are predictive factors of OS. • Increased values may justify treatment intensification in these patients.

Dynamic contrast-enhanced case-control analysis in 3T MRI of prostate cancer can help to characterize tumor aggressiveness.

PURPOSE: The aim of this work is to establish normality and tumor tissue ranges for perfusion parameters from dynamic contrast-enhanced (DCE) MR of the peripheral prostate at 3T and to compare the diagnostic performance of quantitative and semi-quantitative parameters. MATERIALS AND METHODS: Thirty-six patients with prostate carcinomas (18 Gleason-6, 15 Gleason-7, and 3 Gleason-8) and 33 healthy subjects were included. Image analysis workflow comprised four steps: manual segmentation of whole prostate and lesions, series registration, voxelwise T1 mapping and calculation of pharmacokinetic and semi-quantitative parameters. RESULTS: Ktrans, ve, upslope and AUC60 showed statistically significant differences between healthy peripheral areas and tumors. Curve type showed no association with healthy/tumor peripheral areas (chi-square=0.702). Areas under the ROC curves were 0.64 (95% CI: 0.54-0.75), 0.70 (0.60-0.80), 0.62 (0.51-0.72) and 0.63 (0.52-0.74) for Ktrans, ve, upslope and AUC60, respectively. The optimal cutoff values were: Ktrans=0.21min-1 (sensitivity=0.61, specificity=0.64), ve=0.36 (0.63, 0.71), upslope=0.59 (0.59, 0.59) and AUC60=2.4 (0.63, 0.64). Significant differences were found between Gleason scores 6 and 7 for normalized Ktrans, upslope and AUC60, with good diagnostic accuracy (area under ROC curve 0.80, 95% CI: 0.60-1.00). CONCLUSION: Quantitative (Ktrans and ve) and semi-quantitative (upslope and AUC60) perfusion parameters showed significant differences between tumors and control areas in the peripheral prostate. Normalized Ktrans, upslope and AUC60 values might characterize tumor aggressiveness.

Automatic individual arterial input functions calculated from PCA outperform manual and population-averaged approaches for the pharmacokinetic modeling of DCE-MR images.

BACKGROUND: To introduce a segmentation method to calculate an automatic arterial input function (AIF) based on principal component analysis (PCA) of dynamic contrast enhanced MR (DCE-MR) imaging and compare it with individual manually selected and population-averaged AIFs using calculated pharmacokinetic parameters. METHODS: The study included 65 individuals with prostate examinations (27 tumors and 38 controls). Manual AIFs were individually extracted and also averaged to obtain a population AIF. Automatic AIFs were individually obtained by applying PCA to volumetric DCE-MR imaging data and finding the highest correlation of the PCs with a reference AIF. Variability was assessed using coefficients of variation and repeated measures tests. The different AIFs were used as inputs to the pharmacokinetic model and correlation coefficients, Bland-Altman plots and analysis of variance tests were obtained to compare the results. RESULTS: Automatic PCA-based AIFs were successfully extracted in all cases. The manual and PCA-based AIFs showed good correlation (r between pharmacokinetic parameters ranging from 0.74 to 0.95), with differences below the manual individual variability (RMSCV up to 27.3%). The population-averaged AIF showed larger differences (r from 0.30 to 0.61). CONCLUSION: The automatic PCA-based approach minimizes the variability associated to obtaining individual volume-based AIFs in DCE-MR studies of the prostate.

Quantitative MR perfusion parameters related to survival time in high-grade gliomas.

OBJECTIVES: To evaluate the quantitative parameters obtained from dynamic MR T2*-weighted images as predictors of survival taking into consideration the biasing effects of other survival-related covariates. METHODS: Thirty-nine patients (60 ± 14 years; survival 267 ± 191 days) with high-grade gliomas (8 grade III, 31 grade IV) were retrospectively included in the study. Additional data incorporated Karnofsky performance scale, tumour resection extension after surgery and type of treatment. Dynamic T2*-weighted MRI was acquired before treatment. Tumour curves were extracted for each voxel, and several quantitative parameters were obtained from the whole tumour volume and the 10 % maximum values. Additional image covariates included the presence of necrosis, single or multiple lesions, and tumour and oedema volumes. The relationship between quantitative parameters and survival was assessed using clusterisation techniques and the log-rank method. Cox regression analysis was used to evaluate each parameter's predictive value. RESULTS: Only the mean of the 10 % maximum values of the transfer coefficient showed an independent relationship with patient survival (log-rank chi-squared test <0.001, Cox regression P = 0.015), with higher values corresponding to lower survival rates. CONCLUSIONS: High maximum transfer coefficient values show an independent statistical relationship with low survival in high-grade glioma patients. This imaging biomarker can be used as a predictor of prognosis.

[Functional neuroimaging in the study of aggressive behaviour in patients with schizophrenia]. / Neuroimagen funcional en el estudio de las conductas agresivas en pacientes con esquizofrenia.

INTRODUCTION: Although aggressive behaviours are not always very highly prevalent in schizophrenia, their occurrence does represent a significant problem for patients and those around them. Although neuroimaging studies have made it possible to further our knowledge of the biology of these behaviours, there is still a notable degree of clinical heterogeneity in the study samples that makes it difficult to obtain conclusive results that can be compared with each other. AIM: To determine whether there are variations in the brain activity, as measured with functional magnetic resonance imaging, of a homogenous group of patients with schizophrenia and aggressive behaviour. PATIENTS AND METHODS: The sample consisted of 32 patients with refractory schizophrenia and auditory hallucinations selected for the study. The subjects were submitted to a functional magnetic resonance imaging examination using an auditory paradigm with emotional stimulation, while the degree of aggressiveness was measured by means of the Brief Psychiatric Rating Scale. RESULTS: Significant correlations were found between functional activation and the degree of aggressiveness, which show focal hyperactivations in patients with a greater association to violent behaviours. The areas identified were located in the left hippocampus (p < 0.003, corrected) and in the right medial frontal gyrus (p < 0.004, corrected). CONCLUSIONS: This study determines the association between the degree of aggressiveness and certain regions in the brain that are responsible for cognitive and emotional processing in a phenotypically very homogenous group of patients with chronic auditory hallucinations and schizophrenia. This alteration of the neuronal circuits can favour loss in the processes involved in empathy and sensitivity, thus favouring the appearance of aggressive behaviours.

Neuroimagen funcional en el estudio de las conductas agresivas en pacientes con esquizofrenia / Functional neuroimaging in the study of aggressive behaviour in patients with schizophrenia

Introduction. Although aggressive behaviours are not always very highly prevalent in schizophrenia, their occurrence does represent a significant problem for patients and those around them. Although neuroimaging studies have made it possible to further our knowledge of the biology of these behaviours, there is still a notable degree of clinical heterogeneity in the study samples that makes it difficult to obtain conclusive results that can be compared with each other. Aim. To determine whether there are variations in the brain activity, as measured with functional magnetic resonance imaging, of a homogenous group of patients with schizophrenia and aggressive behaviour. Patients and methods. The sample consisted of 32 patients with refractory schizophrenia and auditory hallucinations selected for the study. The subjects were submitted to a functional magnetic resonance imaging examination using an auditory paradigm with emotional stimulation, while the degree of aggressiveness was measured by means of the Brief Psychiatric Rating Scale. Results. Significant correlations were found between functional activation and the degree of aggressiveness, which show focal hyperactivations in patients with a greater association to violent behaviours. The areas identified were located in the left hippocampus (p < 0.003, corrected) and in the right medial frontal gyrus (p < 0.004, corrected). Conclusions. This study determines the association between the degree of aggressiveness and certain regions in the brain that are responsible for cognitive and emotional processing in a phenotypically very homogenous group of patients with chronic auditory hallucinations and schizophrenia. This alteration of the neuronal circuits can favour loss in the processes involved in empathy and sensitivity, thus favouring the appearance of aggressive behaviours(AU)

Introducción. Aunque las conductas agresivas no tienen una prevalencia muy elevada en la esquizofrenia, su desarrollo supone un problema significativo para los pacientes y su entorno. Pese a que los estudios de neuroimagen han permitido profundizar en el conocimiento biológico de estas conductas, sigue existiendo una notable heterogeneidad clínica en las muestras de estudio que hace difícil la obtención de resultados concluyentes y comparables entre sí. Objetivo. Determinar si existen variaciones en la actividad cerebral medidas con resonancia magnética funcional en un grupo homogéneo de pacientes con esquizofrenia y conducta agresiva. Pacientes y métodos. Se seleccionaron 32 pacientes con esquizofrenia y alucinaciones auditivas resistentes al tratamiento. Los sujetos se sometieron a una exploración por resonancia magnética funcional utilizando un paradigma auditivo de estimulación emocional, al tiempo que se recogió el grado de agresividad a través de la Brief Psychiatric Rating Scale. Resultados. Se obtuvieron correlaciones significativas entre la activación funcional y el grado de agresividad, que muestran hiperactivaciones focales en aquellos pacientes con mayor asociación a conductas violentas. Las áreas identificadas se localizaron en el hipocampo izquierdo (p < 0,003, corregida) y en la circunvolución frontal media derecha (p < 0,004, corregida). Conclusiones. Este estudio determina la asociación entre el grado de agresividad y ciertas regiones cerebrales responsables del procesamiento cognitivo y emocional en un grupo fenotípicamente muy homogéneo de pacientes con esquizofrenia y alucinaciones auditivas crónicas. Esta alteración de los circuitos neuronales puede favorecer una pérdida en los procesos de empatía y sensibilidad, favoreciendo la aparición de conductas agresivas(AU)

Magnetic resonance pharmacokinetic imaging clusterization of hepatocellular carcinomas as a means to grade tumor aggressiveness.

Hepatocellular carcinoma (HCC) management takes into account clinical and radiological findings, such as tumor stage, hepatic functional status and clinical symptoms. It is necessary to evaluate the number, size and location of the lesions. However, lesion aggressiveness is not considered in this therapeutic workflow, although the biology and the growth rate of the lesions have an important impact on survival. The aim of this work was to establish if the quantitative pharmacokinetic assessment of dynamic contrast-enhanced magnetic resonance images of HCC can separate lesions with different microvascular properties and biological evolution. Forty five patients with HCC and dynamic contrast-enhanced MRI examinations were included and several pharmacokinetic parameters were calculated. Statistical clusterization techniques were applied and two clearly distinct groups were obtained by using vascular properties and average lesion size. These groups differed by the proportion of deceased patients, although no statistically significant differences were found between the average survival times of both groups.

Assessment of 2D and 3D fractal dimension measurements of trabecular bone from high-spatial resolution magnetic resonance images at 3 T.

PURPOSE: In vivo two-dimensional (2D) fractal dimension (D2D) analysis of the cancellous bone at 1.5 T has been related to bone structural complexity and shown to be a potential imaging-based biomarker for osteoporosis. The objectives of this study were to assess at 3 T the in vivo feasibility of three-dimensional (3D) bone fractal dimension (D3D) analysis, analyze the relationship of D2D and D3D with osteoporosis, and investigate the relationship of D3D with spinal bone mineral density (BMD). METHODS: A total of 24 female subjects (67 +/- 7 yr old, mean +/- SD) was included in this study. The cohort consisted of 12 healthy volunteers and 12 patients with osteoporosis. MR image acquisitions were performed in the nondominant metaphysis of the distal radius with a 3 T MR scanner and an isotropic resolution of 180 microm. After segmentation and structural reconstruction, 2D and 3D box-counting algorithms were applied to calculate the fractal complexity of the cancellous bone. D2D and D3D values were compared between patients with osteoporosis and healthy subjects, and their relationship with radius BV/TV and spinal BMD was also assessed. RESULTS: Significant differences between healthy subjects and patients with osteoporosis were obtained for D3D (p < 0.001), with less differentiation for D2D (p = 0.04). The relationship between fractal dimension and BMD was not significant (r = 0.43, p = 0.16 and r = 0.23, p = 0.48, for D2D and D3D, respectively). CONCLUSIONS: The feasibility of trabecular bone D3D calculations at 3 T and the relationship of both D2D and D3D parameters with osteoporosis were demonstrated, with a better differentiation for the 3D method. Furthermore, the D3D parameter has probably a different nature of information regarding the trabecular bone status not directly explained by BMD alone. Future studies with subjects with osteopenia and larger sample sizes are warranted to further establish the potential of D2D and D3D in the study of osteoporosis.