Specialization and integration of functional thalamocortical connectivity in the human infant.

Connections between the thalamus and cortex develop rapidly before birth, and aberrant cerebral maturation during this period may underlie a number of neurodevelopmental disorders. To define functional thalamocortical connectivity at the normal time of birth, we used functional MRI (fMRI) to measure blood oxygen level-dependent (BOLD) signals in 66 infants, 47 of whom were at high risk of neurocognitive impairment because of birth before 33 wk of gestation and 19 of whom were term infants. We segmented the thalamus based on correlation with functionally defined cortical components using independent component analysis (ICA) and seed-based correlations. After parcellating the cortex using ICA and segmenting the thalamus based on dominant connections with cortical parcellations, we observed a near-facsimile of the adult functional parcellation. Additional analysis revealed that BOLD signal in heteromodal association cortex typically had more widespread and overlapping thalamic representations than primary sensory cortex. Notably, more extreme prematurity was associated with increased functional connectivity between thalamus and lateral primary sensory cortex but reduced connectivity between thalamus and cortex in the prefrontal, insular and anterior cingulate regions. This work suggests that, in early infancy, functional integration through thalamocortical connections depends on significant functional overlap in the topographic organization of the thalamus and that the experience of premature extrauterine life modulates network development, altering the maturation of networks thought to support salience, executive, integrative, and cognitive functions.

Management of children and young people with idiopathic pituitary stalk thickening, central diabetes insipidus, or both: a national clinical practice consensus guideline.

Unexplained or idiopathic pituitary stalk thickening or central diabetes insipidus not only harbours rare occult malignancies in 40% of cases but can also reflect benign congenital defects. Between 2014 and 2019, a multidisciplinary, expert national guideline development group in the UK systematically developed a management flowchart and clinical practice guideline to inform specialist care and improve outcomes in children and young people (aged <19 years) with idiopathic pituitary stalk thickening, central diabetes insipidus, or both. All such cases of idiopathic pituitary stalk thickening and central diabetes insipidus require dynamic pituitary function testing, specialist pituitary imaging, measurement of serum ß-human chorionic gonadotropin and alpha-fetoprotein concentrations, chest x-ray, abdominal ultrasonography, optometry, and skeletal survey for occult disease. Stalk thickening of 4 mm or more at the optic chiasm, 3 mm or more at pituitary insertion, or both, is potentially pathological, particularly if an endocrinopathy or visual impairment coexists. In this guideline, we define the role of surveillance, cerebrospinal fluid tumour markers, whole-body imaging, indications, timing and risks of stalk biopsy, and criteria for discharge. We encourage a registry of outcomes to validate the systematic approach described in this guideline and research to establish typical paediatric stalk sizes and the possible role of novel biomarkers, imaging techniques, or both, in diagnosis.

Magnetic resonance imaging of white matter diseases of prematurity.

Periventricular leucomalacia (PVL) and parenchymal venous infarction complicating germinal matrix/intraventricular haemorrhage have long been recognised as the two significant white matter diseases responsible for the majority of cases of cerebral palsy in survivors of preterm birth. However, more recent studies using magnetic resonance imaging to assess the preterm brain have documented two new appearances, adding to the spectrum of white matter disease of prematurity: punctate white matter lesions, and diffuse excessive high signal intensity (DEHSI). These appear to be more common than PVL but less significant in terms of their impact on individual neurodevelopment. They may, however, be associated with later cognitive and behavioural disorders known to be common following preterm birth. It remains unclear whether PVL, punctate lesions, and DEHSI represent a continuum of disorders occurring as a result of a similar injurious process to the developing white matter. This review discusses the role of MR imaging in investigating these three disorders in terms of aetiology, pathology, and outcome.

Postcontrast CT extravasation is associated with hematoma expansion in CTA spot negative patients.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the effect of postcontrast CT (PCCT) leakage (PCL) on hematoma growth in CTA spot negative patients. METHODS: A retrospective study of 61 patients presenting within 6 hours of primary ICH onset imaged with CT angiography (CTA) and PCCT. Presence of CTA spot sign and PCL were documented. PCL was defined as the presence of contrast extravasation on the PCCT study at a location remote from the CTA spot sign if present. Hematoma expansion was defined as >6 mL or 30% hematoma enlargement. Patients were dichotomized by CTA spot sign presence and PCL and compared for baseline demographic data, hematoma size, and growth using the unpaired t test and Mann-Whitney test for continuous and categorical data, respectively. A probability value <0.05 was considered significant. RESULTS: PCL was present in 11/61 patients (18%), occurring in 5 without a spot sign (45%). Spot negative PCL patients demonstrated larger absolute (P=0.02) and percentage hematoma growth (P=0.02) compared to those without PCL. The mean volume and percent increase was 6.7 mL and 26%, respectively. Inclusion of PCL together with CTA spot sign as risk factor for hematoma expansion increased sensitivity from 0.78 (95% CI; 0.52 to 0.94) to 0.94 (95% CI; 0.72 to 1.00) and NPV from 0.90 (95% CI; 0.76 to 0.97) to 0.97 (95% CI; 0.85 to 1.00). CONCLUSIONS: Inclusion of PCCT in the investigation of ICH patients allows detection of PCL which, together with the CTA spot sign, increases sensitivity and negative predictive value for predicting hematoma expansion. This finding should be validated in larger studies.