Longitudinal reproducibility and accuracy of pseudo-continuous arterial spin-labeled perfusion MR imaging in typically developing children.

PURPOSE: To evaluate the longitudinal repeatability and accuracy of cerebral blood flow (CBF) measurements by using pseudo-continuous arterial spin-labeled (pCASL) perfusion magnetic resonance (MR) imaging in typically developing children. MATERIALS AND METHODS: Institutional review board approval with HIPAA compliance and informed consent were obtained. Twenty-two children aged 7-17 years underwent repeated pCASL examinations 2-4 weeks apart with a 3-T MR imager, along with in vivo blood T1 and arterial transit time measurements. Phase-contrast (PC) MR imaging was performed as the reference standard for global blood flow volume. Intraclass correlation coefficient (ICC) and within-subject coefficient of variation (wsCV) were used to evaluate accuracy and repeatability. RESULTS: The accuracy of pCASL against the reference standard of PC MR imaging increased on incorporating subjectwise in vivo blood T1 measurement (ICC: 0.32 vs 0.58). The ICC further increased to 0.65 by using a population-based model of blood T1. Additionally, CBF measurements with use of pCASL demonstrated a moderate to good level of longitudinal repeatability in whole brain (ICC = 0.61, wsCV = 15%), in gray matter (ICC = 0.65, wsCV = 14%), and across 16 brain regions (mean ICC = 0.55, wsCV = 17%). The mean arterial transit time was 1538 msec ± 123 (standard deviation) in the pediatric cohort studied, which showed an increasing trend with age (P = .043). CONCLUSION: Incorporating developmental changes in blood T1 is important for improving the accuracy of pCASL CBF measurements in children and adolescents; the noninvasive nature, accuracy, and longitudinal repeatability should facilitate the use of pCASL perfusion MR imaging in neurodevelopmental studies.

Suicidal ideation and self-harm behavior in a community sample of preadolescent youth: a case-control study.

OBJECTIVE: Research has focused on understanding risk factors associated with suicidal ideation and self-harm behaviors in older youth, but less is known regarding these behaviors in preadolescents. We examined characteristics associated with suicidal ideation and self-harm behavior in youth aged 10-13 years. DESIGN/METHODS: A community sample of 387 youth was enrolled in a prospective study assessing precursors of risk behaviors. Twenty-three subjects endorsing items regarding suicidal ideation or self-harm behaviors (Achenbach's Youth Self-Report) (endorsers) were matched with 23 non-endorsers. Groups were compared on problem behaviors, impulsivity, neurocognitive function, risk behaviors, and other variables. RESULTS: Endorsers had higher levels of impulsivity, were more likely in borderline/clinical range on 5 of 8 Youth Self-Report Syndrome scales, and reported more risk taking. Endorsers and non-endorsers were similar in neurocognitive function. More non-endorsers were on stimulants, but groups were similar in parental monitoring and parental report of behavioral/emotional issues, socioeconomic status, and marital status. CONCLUSION: In this study, preadolescent endorsers report significantly more problem behaviors than non-endorsers. However, parental monitoring and parent report of problems were similar between groups. Given these findings, we suggest that at-risk youth may be underrecognized at young ages.

In vivo venous blood T1 measurement using inversion recovery true-FISP in children and adults.

A time-efficient method is described for in vivo venous blood T(1) measurement using multiphase inversion-recovery-prepared balanced steady-state free precession imaging. Computer simulations and validation experiments using a flow phantom were carried out to demonstrate the accuracy of the proposed method for measuring blood T(1) by taking advantage of the continuous inflow of fresh blood with longitudinal magnetization undisturbed by previous radiofrequency pulses. In vivo measurement of venous blood T(1) in the sagittal sinus was carried out in 26 healthy children and adults aged 7-39 years. The measured venous blood T(1) values decreased with age as a whole (P = 0.006) and were higher in females than males (P = 0.013), matching the expected developmental changes and gender differences in human hematocrit level. The estimated mean blood T(1) values were highly correlated with normal hematocrit levels across age and gender groups (Spearman's r = 0.93, P = 0.008). The longitudinal repeatability of this technique was 4.0% as measured by the within-subject coefficient of variation. The proposed multiphase inversion recovery-prepared balanced steady-state free precession imaging method is a feasible technique for fast (< 1 min) and reliable in vivo venous blood T(1) measurement and may serve as an index of hematocrit level in individual subjects.