Prospective evaluation of term neonate brain damage following preceding hypoxic sentinel events using enhanced T2* weighted angiography (eSWAN).

PURPOSE: To evaluate the brain damage of term neonates with evidence of a preceding hypoxic sentinel event using eSWAN prospectively. METHODS: The study was approved by the institutional research ethics committee. Among the neonates who were examined during the first 8 days after birth with conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) and eSWAN, 39 neonates with a preceding acute hypoxic sentinel event were divided into two groups: the hypoxic ischaemic encephalopathy (HIE) group and the high-risk group. Twenty-five neonates were normal control subjects. Conventional MRI, DWI, and T2* and R2* maps from eSWAN were assessed. T2* and R2* values from T2* and R2* maps were calculated in predefined regions in the HIE and high-risk groups and then compared with those in control subjects. RESULTS: The neonates in the HIE and high-risk groups showed a high percentage of cerebral oedema and periventricular white-matter (PWM) lesions. Cerebral oedema and haemorrhagic lesions of PWM were more highly visible on the T2* map compared with conventional MRI: cerebral oedema was illustrated as a high T2* area and haemorrhagic lesions had a significantly lower T2* on the T2* map. Lower R2* values of lentiform nuclei (LN) and a higher T2* and lower R2* of frontal white matter (FWM) were found in neonates in the HIE group relative to those of normal controls. The T2* value of LN in the high-risk group was higher than that of the normal controls. CONCLUSIONS: The T2* map from eSWAN is useful in detecting cerebral oedema and haemorrhagic lesions of PWM in neonates. The measurement of T2* and R2* values is helpful in assessing the LN and FWM damage in neonates following a hypoxic sentinel event.

Assessment of levator ani morphology and function in asymptomatic nulliparous women via static and dynamic magnetic resonance imaging.

OBJECTIVE: To evaluate levator ani morphology and function in healthy nulliparous women using static and dynamic magnetic resonance imaging. METHODS: Eighty asymptomatic, healthy nulliparous Chinese women (mean age, 25.3±3.5years) volunteered for the present study. Static T2-weighted fast spin-echo images were employed to evaluate levator ani morphology; dynamic T2-weighted fast imaging employing steady-state acquisition was used to evaluate its function. A 2 samples t test was employed to compare groups. RESULTS: No morphologic abnormality was detected in the 80 healthy nulliparous women. However, 15% (12/80) of women had various degrees of pelvic organ descent below the pubococcygeal line. In these women, the width of the pubic portion of the levator ani was significantly reduced during straining, whereas the levator plate angle, the levator hiatus area, and the H and M line lengths were enlarged. These changes were associated with weakened levator ani function and pelvic floor laxity. CONCLUSION: Functional abnormality of the levator ani muscle was noted in nulliparous women at static and dynamic magnetic resonance imaging. Further follow-up investigation is needed to confirm whether women with functional abnormality are more likely to develop a prolapse after vaginal birth.

Gadolinium-enhanced magnetic resonance imaging of the knee: an experimental approach.

PURPOSE: The purpose of this study was to examine gadolinium-enhanced magnetic resonance imaging (MRI) for monitoring cartilage degeneration. METHODS: This is a proof-of-concept study in an animal model. Adult New Zealand rabbits were randomly stratified into five groups. Papain was injected intra-articularly in the right knee in four groups to establish the stages of cartilage degeneration. The left knee and group 5 served as controls. Bilateral MRI was performed 24 h after the initial injection of papain, and 1 week, 1 month, and 3 months following three papain injections. Injection of the contrast agent was followed by bilateral MRI examination immediately upon injection, and at 2 and 4 h post-injection. Signal intensities of articular cartilage and peripheral soft tissues were obtained before animals were sacrificed. Post-mortem bilateral cartilage specimens were studied histologically. RESULTS: Histopathology results verified the staged degeneration of papain-treated articular cartilage. Differences in cartilage signal intensity were significant for the staged model using a special three-dimensional MRI method (P < 0.05) but not using ordinary MRI. No differences were observed within or between the control groups (P > 0.05). CONCLUSIONS: Contrast-enhanced MRI examination may be a viable tool for early diagnosis of osteoarticular disease. Prospective studies are warranted to evaluate the potential for clinical application.