Persistent MR-detectable modifications indicate a rearrangement within forebrain networks, accounting for long-lasting behavioural changes as a function of developmental 5-HT7-R stimulation.

Differentiating bowel intussusception occurring in adults from other bowel diseases represents a diagnostic problem because this condition is not a common finding. Contrast radiography, computed tomography, magnetic resonance imaging, and abdominal ultrasonography are imaging techniques suitable for this diagnosis. Sonography is easy to perform, reproducible, and less invasive than the other techniques. The aim of the present study was to evaluate the diagnostic utility of abdominal sonography in four patients affected by bowel intussusception and to assess the advantages offered by this method.

The investigation of age-related changes in muscle microstructure between developmental and healthy adult mice may help us to understand the clinical features of early-onset muscle diseases, such as Duchenne muscular dystrophy. We investigated the evolution of mouse hind-limb muscle microstructure using diffusion imaging of in vivo and in vitro samples from both actively growing and mature mice. Mean apparent diffusion coefficients (ADCs) of the gastrocnemius and tibialis anterior muscles were determined as a function of diffusion time (Δ), age (7.5, 22 and 44 weeks) and diffusion gradient direction, applied parallel or transverse to the principal axis of the muscle fibres. We investigated a wide range of diffusion times with the goal of probing a range of diffusion lengths characteristic of muscle microstructure. We compared the diffusion time-dependent ADC of hind-limb muscles with histology. ADC was found to vary as a function of diffusion time in muscles at all stages of maturation. Muscle water diffusivity was higher in younger (7.5 weeks) than in adult (22 and 44 weeks) mice, whereas no differences were observed between the older ages. In vitro data showed the same diffusivity pattern as in vivo data. The highlighted differences in diffusion properties between young and mature muscles suggested differences in underlying muscle microstructure, which were confirmed by histological assessment. In particular, although diffusion was more restricted in older muscle, muscle fibre size increased significantly from young to adult age. The extracellular space decreased with age by only~1%. This suggests that the observed diffusivity differences between young and adult muscles may be caused by increased membrane permeability in younger muscle associated with properties of the sarcolemma. KEYWORDS apparent diffusion coefficient, diffusion MRI, diffusion-weighted imaging, hind-limb muscles, histology, maturation, mouse, time-dependent diffusion MRI | INTRODUCTIONSkeletal muscle is the most abundant tissue in the human body, comprising 30-40% of the body weight, 1 and is the major site of metabolic activity. 2 Its function, which is strictly dependent on muscle cytoarchitecture, 3 enables vital actions, i.e. breathing, posture and locomotion, and affects systemic processes, such as homeostasis and the immune response.Skeletal muscle mass and fibre size vary according to physiological and pathological conditions, 4 which influence the pathways regulating the balance between protein synthesis and degradation within muscle fibres. 5 During postnatal development, this equilibrium, which determines cell Abbreviations used: ADC, apparent diffusion coefficient; ANOVA, analysis of variance; DTI, diffusion tensor imaging; DWI, diffusion-weighted imaging; EBD, Evans blue dye; FFPE, formalin-fixed, paraffin-embedded; FOV, field of view; FSE, fast spin echo; GA, gastrocnemius; G diff , diffusion gradient direction; H&E, haematoxylin and eosin; i.d., inner diameter; MRI, magnetic resonance imaging; NBF, neutral buffered formalin;...

A novel diffusion-weighted magnetic resonance imaging protocol sensitive to contraction of individual skeletal motor units was developed. We applied this technique to the lower limb muscles of 4 patients with confirmed amyotrophic lateral sclerosis (ALS) and 6 healthy controls. A 3-minute scan revealed florid fasciculation in ALS patients, involving both superficial and deep muscles, and at a frequency higher than in healthy controls. This novel imaging technique reveals hitherto unobtainable information on human motor unit structure and function, which may allow earlier diagnosis and recruitment to clinical trials.