Biomedical subjects
Publications and source records attributed to Luca Ramenghi.
We report on the brain diffusion MR imaging findings in a neonate with severe hypernatremic dehydration, which resulted in cerebral edema (osmotic edema) and in apparent diffusion coefficient decrease, despite a careful and slow rehydration. This report provides in vivo insight into nervous cell response to osmotic challenge.
Withdrawal and infusion of blood via umbilical catheters can affect cerebral blood flow in preterm infants. We compared the effects on cerebral perfusion of 3 ml/kg blood withdrawal and infusion via umbilical arterial (UAC) and venous (UVC) catheters in 16 infants < or =32 weeks gestation, age <24 h, on mechanical ventilation. Near infrared spectroscopy was used to monitor changes in cerebral oxy- and deoxyhemoglobin, total cerebral hemoglobin (an index of cerebral blood volume; CBV) and HbD (an index of cerebral intravascular oxygenation). In 10 infants the study was repeated 1 h after intravenous administration of 10 mg/kg ibuprofen as prophylaxis against PDA. Withdrawal and infusion via the UVC caused significant MABP and concordant HbD and CBV changes. Smaller modifications were seen following blood withdrawal and infusion via the UAC. Ibuprofen attenuated cerebral hemodynamic changes associated with withdrawal, but not infusion, from UAC and UVC.
BACKGROUND AND PURPOSE: Diffusion-weighted MR imaging studies of normal brain development have focused on premature babies who were free of focal lesions on conventional MR images. The condition of prematurity, however, is dissimilar to intrauterine life. We sought to establish normal values of fetal brain apparent diffusion coefficient (ADC) to highlight its abnormal changes in pathologic conditions and to obtain information about normal brain development. METHODS: We measured the ADC, in utero, by using an echo-planar three-axes diffusion-sensitized sequence (b factor, 0 and 600 s/mm(2)), in frontal and occipital white matter and basal ganglia gray matter of 15 fetuses. Their gestational ages ranged from 22 to 35 weeks, and the postnatal MR images or sonograms revealed normal brain. RESULTS: Mean ADC value was 1.96 +/- 0.1 micro m(2)/ms (SD) in frontal white matter, 1.95 +/- 0.1 micro m(2)/ms in occipital white matter, and 1.56 +/- 0.1 micro m(2)/ms in basal ganglia. A significant negative correlation between ADC and gestational age was found for basal ganglia, whereas only a trend was present for frontal white matter. CONCLUSION: Although moderately higher, the ADC determinations we obtained are consistent with those reported in the literature in postnatal studies performed in premature babies.