Preparing children with a mock scanner training protocol results in high quality structural and functional MRI scans

We evaluated the use of a mock scanner training protocol as an alternative for sedation and for preparing young children for (functional) magnetic resonance imaging (MRI). Children with severe mental retardation or developmental disorders were excluded. A group of 90 children (median age 6.5 years, range 3.65–14.5 years) participated in this study. Children were referred to the actual MRI investigation only when they passed the training. We assessed the pass rate of the mock scanner training sessions. In addition, the quality of both structural and functional MRI (fMRI) scans was rated on a semi-quantitative scale. The overall pass rate of the mock scanner training sessions was 85/90. Structural scans of diagnostic quality were obtained in 81/90 children, and fMRI scans with sufficient quality for further analysis were obtained in 30/43 of the children. Even in children under 7 years of age, who are generally sedated, the success rate of structural scans with diagnostic quality was 53/60. FMRI scans with sufficient quality were obtained in 23/36 of the children in this younger age group. The association between age and proportion of children with fMRI scans of sufficient quality was not statistically significant. We conclude that a mock MRI scanner training protocol can be useful to prepare children for a diagnostic MRI scan. It may reduce the need for sedation in young children undergoing MRI. Our protocol is also effective in preparing young children to participate in fMRI investigations

Global and Regional Differences in Brain Anatomy of Young Children Born Small for Gestational Age

In children who are born small for gestational age (SGA), an adverse intrauterine environment has led to underdevelopment of both the body and the brain. The delay in body growth is (partially) restored during the first two years in a majority of these children. In addition to a negative influence on these physical parameters, decreased levels of intelligence and cognitive impairments have been described in children born SGA. In this study, we used magnetic resonance imaging to examine brain anatomy in 4- to 7-year-old SGA children with and without complete bodily catch-up growth and compared them to healthy children born appropriate for gestational age. Our findings demonstrate that these children strongly differ on brain organisation when compared with healthy controls relating to both global and regional anatomical differences. Children born SGA displayed reduced cerebral and cerebellar grey and white matter volumes, smaller volumes of subcortical structures and reduced cortical surface area. Regional differences in prefrontal cortical thickness suggest a different development of the cerebral cortex. SGA children with bodily catch-up growth constitute an intermediate between those children without catch-up growth and healthy controls. Therefore, bodily catch-up growth in children born SGA does not implicate full catch-up growth of the brain

Using fMRI to Investigate Memory in Young Children Born Small for Gestational Age

Intrauterine growth restriction (IUGR) can lead to infants being born small for gestational age (SGA). SGA is associated with differences in brain anatomy and impaired cognition. We investigated learning and memory in children born SGA using neuropsychological testing and functional Magnetic Resonance Imaging (fMRI). 18 children born appropriate for gestational age (AGA) and 34 SGA born children (18 with and 16 without postnatal catch-up growth) participated in this study. All children were between 4 and 7 years old. Cognitive functioning was assessed by IQ and memory testing (Digit/Word Span and Location Learning). A newly developed fMRI picture encoding task was completed by all children in order to assess brain regions involved in memory processes. Neuropsychological testing demonstrated that SGA children had IQ's within the normal range but lower than in AGA and poorer performances across measures of memory. Using fMRI, we observed memory related activity in posterior parahippocampal gyrus as well as the hippocampus proper. Additionally, activation was seen bilaterally in the prefrontal gyrus. Children born SGA showed less activation in the left parahippocampal region compared to AGA. This is the first fMRI study demonstrating different brain activation patterns in 4-7 year old children born SGA, suggesting that intrauterine growth restriction continues to affect neural functioning in children later-o

BOLD activation.

<p>BOLD activation maps related to encoding novel pictures of the picture encoding task. Upper part: sagittal cross-sections (x = -30, y = -90, z = -9) in AGA (A), SGA+ (B) and SGA- (C) children, representing the left ventral stream with significant activation from the occipital lobe via the fusiform gyrus into the parahippocampal gyrus/hippocampal formation. Functional results are thresholded at p<0.005 for display purposes. Lower part: Coronal cross-sections of the parahippocampal gyrus/hippocampal formation area (x = -21, y = -27, z = -24) in AGA (A), SGA+ (B) and SGA- (C) children. Images thresholded at P<0.005 for display purposes. AGA = average for gestational age, SGA+ = small for gestational age with catch-up growth, SGA- = small for gestational age without catch-up growth.</p

Characteristics of study groups (N = 52 children).

<p>Note. Data (except gender and handedness) are presented as mean (± standard deviation); p-value< 0.05 is considered significant, p-values between 0.05 and 0.10 are reported. AGA = appropriate for gestational age; SGA+ = small for gestational age with postnatal catch up growth; SGA– = small for gestational age without postnatal catch up growth; MRI = magnetic resonance imaging; SD = standard deviation; ns = non significant.</p><p>^aWhen birth length was not available, measure of body length at first visit at child health centre was taken</p><p>^bweight for length SD</p><p>Characteristics of study groups (N = 52 children).</p

Whole brain analysis; regions of significant increased activation for novel relative to overlearned pictures during the Picture Encoding Test (N = 52).

<p>Note. AGA = appropriate for gestational age (n = 18); SGA+ = small for gestational age with postnatal catch up growth (n = 18); SGA– = small for gestational age without postnatal catch up growth (n = 16); MNI = Montreal Neurological Institute template; mm = millimeter; Z score = brain activation difference between novel and overlearned (baseline) condition.</p><p>^a Regions significant at false discovery rate corrected p <0.05</p><p>^b Regions significant at uncorrected p < 0.001</p><p>^c Small volume correction: false discovery rate corrected p = 0.032</p><p>^d Small volume correction: false discovery rate corrected p = 0.037</p><p>Whole brain analysis; regions of significant increased activation for novel relative to overlearned pictures during the Picture Encoding Test (N = 52).</p

Intelligence, word/ digit spans and location learning (raw scores) of children born AGA, SGA+ and SGA–(N = 52).

<p>Note. data are presented as mean (± standard deviation); AGA = appropriate for gestational age; SGA+ = small for gestational age with postnatal catch up growth; SGA– = small for gestational age without postnatal catch up growth; ns = non significant.</p><p>p-value< 0.05 is considered significant, unless specified otherwise</p><p>a Main effects after covarying for age</p><p>b Main effects after covaring for age and corresponding response times</p><p>c Remains significant after covarying for IQ.</p><p>d Bonferroni corrected level of significance (α/<i>n</i>k) = .01</p><p>Intelligence, word/ digit spans and location learning (raw scores) of children born AGA, SGA+ and SGA–(N = 52).</p

Design of picture encoding and memory task.

<p>(A) The encoding phase consisted of two runs with 30 novel and two recurring overlearned pictures (bird and shoe; presented 13 times), derived from the dummy memory disc which the child practiced at home. Children had to indicate whether the stimuli was an animal or object, while fMRI was administrated. (B) The recognition phase, administrated on a personal desktop computer, presented two times 30 pictures earlier presented in the encoding phase, 26 times two overlearned pictures (bird and shoe) and 60 novel pictures. Children had to decide whether or not the stimuli was earlier presented during the encoding phase. In both phases pictures were presented in random order during 3.0 seconds each, followed by a randomized interstimulus interval of 0.5–2.5 seconds during which a red fixation cross was presented. * Overlearned picture (bird or shoe), used to establish a functional baseline (fMRI)</p

Whole brain activation.

<p>Whole brain activation related to encoding novel pictures during the picture encoding task, overlaid on a customized template (Template-O-Matic). Activation is thresholded at p<0.05, FDR-corrected.</p