Heterogeneity in brain metastases – advanced MRI at the brain-tumour interface predicts aggressive growth patterns.

Background Brain metastases are increasingly common tumours treated as a homogenous group with SRS, surgery and whole brain radiotherapy. However, there are significant rates of local recurrence. We prospectively investigated intra- and inter-tumour heterogeneity in a series of brain metastases undergoing advanced MRI followed by image guided neurosurgical sampling from the leading edge in the course of resection. Method Pre-surgery 3T-MRI was obtained using 32 direction DTI and T1 with gadolinium. Image guided sampling was performed at the leading edge of the tumour as it was removed with reference samples from the core. Histogram analysis of regions of interest were matched to tissue locations. Growth pattern was assessed by a pathologist using a previously described classification and CD34, Ki67, necrosis and cellularity were scored semi-automatically using NIH ImageJ software. Survival and brain recurrence were recorded. Results Twenty-six cases were included. The mean diffusivity (MD) values recorded at the edge of metastases were significantly different in distribution, median and mean from those at the core (Wilcoxon matched pairs, p=.001). There was significantly higher necrosis (p=.026) and a trend to higher CD34 density at the leading edge versus the core. MD and the change in MD across the leading edge correlated with cellularity (r=-.41, p=.047) but did not predict clinical outcomes nor pathological growth pattern. Metastases which appeared more diffusely invasive pathologically had a significantly lower peritumoral fractional anisotropy (FA) (p=.039) suggesting more tract white matter disruption. These tumours also had more dense CD34 staining (r=-.55, p=.041) at their leading edge and a trend to lower survival and more rapid intracranial recurrence. Conclusion There is significant intra-tumoral heterogeneity among brain metastases and assessment of the brain-tumour interface radiologically and biologically may yield more useful information about behaviour and prognosis than assessing the whole metastasis

Diffusion-weighted MRI characteristics of the cerebral metastasis to brain boundary predicts patient outcomes.

DWI demonstrates changes in the tumor, across the tumor edge and in the peritumoral region which may not be visible on conventional MRI and this may be useful in predicting patient outcomes for operated cerebral metastases

Agency performance modulates resting-state variation in prefrontal brain regions

Distinguishing the effects of own from others’ actions is a prerequisite for effective interpersonal functioning. Individuals differ in their ability to do this. For example, difficulties in self-other attribution have been linked to positive symptoms of schizophrenia such as hallucinations, with causally ambiguous situations proving a universal challenge. The goal of the present study was to examine relationships between individual differences in resting-state functional connectivity and self-other attribution performance. Fifty-five healthy adults completed a resting-state fMRI scan and an attribution task that involved tapping at irregular intervals while listening to a tone sequence. The likelihood that tones in the sequence corresponded to the participant's taps was systematically varied. Using group independent component analysis (ICA) and dual regression, we found that connectivity between prefrontal networks associated with self-referential processing and regions sensitive to externally-generated stimuli was modulated by participants’ ability to accurately assess the proportion of tones belonging to self versus other. These findings shed additional light on the neural mechanisms of agency, emphasising that connectivity with prefrontal networks play an important role in self-other differentiation

A voxel-based asymmetry study of the relationship between hemispheric asymmetry and language dominance in Wada tested patients

Determining the anatomical basis of hemispheric language dominance (HLD) remains an important scientific endeavor. The Wada test remains the gold standard test for HLD and provides a unique opportunity to determine the relationship between HLD and hemispheric structural asymmetries on MRI. In this study, we applied a whole‐brain voxel‐based asymmetry (VBA) approach to determine the relationship between interhemispheric structural asymmetries and HLD in a large consecutive sample of Wada tested patients. Of 135 patients, 114 (84.4%) had left HLD, 10 (7.4%) right HLD, and 11 (8.2%) bilateral language representation. Fifty‐four controls were also studied. Right‐handed controls and right‐handed patients with left HLD had comparable structural brain asymmetries in cortical, subcortical, and cerebellar regions that have previously been documented in healthy people. However, these patients and controls differed in structural asymmetry of the mesial temporal lobe and a circumscribed region in the superior temporal gyrus, suggesting that only asymmetries of these regions were due to brain alterations caused by epilepsy. Additional comparisons between patients with left and right HLD, matched for type and location of epilepsy, revealed that structural asymmetries of insula, pars triangularis, inferior temporal gyrus, orbitofrontal cortex, ventral temporo‐occipital cortex, mesial somatosensory cortex, and mesial cerebellum were significantly associated with the side of HLD. Patients with right HLD and bilateral language representation were significantly less right‐handed. These results suggest that structural asymmetries of an insular‐fronto‐temporal network may be related to HLD

TIPIT: A randomised controlled trial of thyroxine in preterm infants under 28 weeks gestation: Magnetic Resonance Imaging and Magnetic Resonance Angiography protocol

<p>Abstract </p> <p>Background</p> <p>Infants born at extreme prematurity are at high risk of developmental disability. A major risk factor for disability is having a low level of thyroid hormone described as hypothyroxinaemia, which is recognised to be a frequent phenomenon in these infants. Derangements of critical thyroid function during the sensitive window in prematurity when early development occurs, may have a range of long term effects for brain development. Further research in preterm infants using neuroimaging techniques will increase our understanding of the specificity of the effects of hypothyroxinaemia on the developing foetal brain. This is an explanatory double blinded randomised controlled trial which is aimed to assess the effect of thyroid hormone supplementation on brain size, key brain structures, extent of myelination, white matter integrity and vessel morphology, somatic growth and the hypothalamic-pituitary-adrenal axis.</p> <p>Methods</p> <p>The study is a multi-centred double blinded randomised controlled trial of thyroid hormone supplementation in babies born below 28 weeks' gestation. All infants will receive either levothyroxine or placebo until 32 weeks corrected gestational age. The primary outcomes will be width of the sub-arachnoid space measured using cranial ultrasound and head circumference at 36 weeks corrected gestational age. The secondary outcomes will be thyroid hormone concentrations, the hypothalamic pituitary axis status and auxological data between birth and expected date of delivery; thyroid gland volume, brain size, volumes of key brain structures, extent of myelination and brain vessel morphology at expected date of delivery and markers of morbidity which include duration of mechanical ventilation and/or oxygen requirement and chronic lung disease.</p> <p><b>Trial registration</b></p> <p>Current Controlled Trials ISRCTN89493983</p

Structure and function of prefrontal cortex in professional musicians

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