Are renal volumes measured by magnetic resonance imaging and three-dimensional ultrasound in the term neonate comparable?

Renal volume, but not renal length, has been shown to be positively correlated with renal function. Three-dimensional (3D) ultrasound and magnetic resonance imaging (MRI) are two modalities used to assess renal volume. The aim of our study was to determine whether 3D ultrasound measurements of renal volume in the neonate are comparable to those of MRI measurements. Preterm and term neonates had an MRI and 3D ultrasound to determine renal volume at the same time as they had an MRI brain scan for other clinical conditions. The preterm neonates were all term corrected age, and the term neonates were 1-4 weeks of age. None of the kidneys examined were abnormal. There were no significant differences in the weight or length of the preterm and term infants at the time of their MRI scan. The left renal length was significantly longer according to MRI measurements than according to 3D ultrasound measurements (p=0.02). Renal volumes of both the left and right kidney were greater when measured by MRI than by 3D ultrasound (p<0.0001, respectively). Total volumes of the kidneys were greater when measured by MRI than by 3D ultrasound (p=0.008). Renal volume in neonates was significantly less when evaluated by 3D ultrasound than by MRI. These results demonstrate that MRI and 3D ultrasound renal volumes are not comparable in the neonatal population and, therefore, the same radiological modality should be used if repeat volume measurements are to be performed.

Do maternal- or pregnancy-associated disease states affect blood pressure in the early neonatal period?

BACKGROUND: Placental vascular changes associated with maternal disease states may affect fetal vascular development. There is evidence suggesting that being born prematurely is associated with a higher blood pressure (BP) in later life. AIM: To determine whether maternal disease state affects BP in the early neonatal period. METHODS: Cohort study of neonates admitted to neonatal intensive care unit with exposure to maternal hypertension and diabetes. Inclusion criteria were neonates greater than 27 weeks gestation not ventilated or requiring inotropes for more than 24 h, materna l hypertension (pregnancy induced or essential) or diabetes of any kind requiring treatment, and spontaneous delivery. Exclusion criteria included chromosomal or congenital anomaly and illicit maternal drug use. Oscillometric BP measurements taken until discharge on days 1, 2, 3, 4, 7, 14, 21 and 28. Placental histopathology was performed. RESULTS: One hundred and ninety infants enrolled, 104 in the control and 86 in the study group. Sixty-five infants were born between 28-31 weeks and 125 infants between 32-41 weeks gestation. Those born between 28-31 weeks with a history of diabetes had a statistically higher systolic, mean and diastolic BP throughout the first 28 days of life (P = 0.001; P = 0.007; P = 0.02). Those born between 32-41 weeks gestation with placental pathology associated with altered uteroplacental perfusion had a higher systolic BP (P = 0.005). CONCLUSIONS: Maternal- or pregnancy-associated disease states appear to influence BP in the early neonatal period. Diabetes and altered placental perfusion were associated with higher BP readings. Clinical significance of these statistically elevated BPs in the early neonatal period is unknown.

Normative blood pressure data in non-ventilated premature neonates from 28-36 weeks gestation.

Blood pressure (BP) measurement in the premature neonate is an essential component of neonatal intensive care. Despite significant advances in neonatal care, the data available on BP in the premature neonate are limited. The aim of this study was to determine normative BP measurements for non-ventilated stable premature neonates of gestation age 28-36 weeks in the first month of life using an oscillometric method. Neonates born at 28-36 weeks gestation who did not require ventilation for >24 h or inotrope support for >24 h were enrolled into the study. Blood pressure measurements were taken on days 1, 2, 3, 4, 7, 14, 21 and 28 where possible prior to discharge. A total of 147 infants were included in the study, and 10th and 90th percentiles BPs were obtained for gestation as well as birthweight. Changes in BP over time for each gestational week were determined. A significant difference in BP from day 1 to day 7 and from day 7 to 14 was observed in those born at less than 31 weeks gestation, and from day 1 to 7 in those born at more than 31 weeks gestation, but not from day 14 to 21 and from day 21 to 28 for any gestation period. Data on BP for stable non-ventilated premature infants using an oscillometric method provide useful information for determining hypotension and hypertension in the premature neonate. Premature neonates stabilize their BP after 14 days of life, and at this time they have a BP similar to that of term infants.

Does extreme prematurity affect kidney volume at term corrected age?

OBJECTIVE: Extreme prematurity exposes the neonate to a number of potential renal insults that may result in a reduced number of glomeruli and/or renal size. This may predispose these individuals to cardiovascular disease later in life. The objective was to determine using magnetic resonance imaging (MRI) whether extreme prematurity results in decreased renal volume. METHODS: Neonates <29 weeks' gestation and term infants undergoing MRI of the brain were enrolled in the study. An MRI was performed at term corrected age in the premature neonate and within the first 4 weeks of life in the term neonate. RESULTS: Seventeen preterm infants and 13 term infants had MRIs performed. There was no significant difference in weight and length at the time of MRI (p = 0.76 and 0.11, respectively). There was no significant difference in total renal volume or total kidney volume to weight ratio between the preterm and term neonates (p = 0.83 and 0.6, respectively). CONCLUSIONS: At term corrected age, extremely premature neonates have the same renal volume as term infants. It is unclear whether renal volume is a good indicator of glomerular number.