الفهرس 
INTRACRANIAL HEMORRHAGEOnly 14 pages are availabe for public view
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Abstract
Neonatal intracranial US has traditionally been performed through theAF. However, the use of the PF approach imaging was found by many authors to significantly augment the diagnostic power of neurologic US in detecting small intraventricular hemorrhages, brainstem hemorrhage and in depicting structural abnormalities of the brainstem and cerebellum.
Because visualization of the occipital horns and the periventricular area is improved when sonograms are obtained through the PF, we studied the efficacy of PF sonography in establishing the diagnosis of various intracranial lesions in neonates
We prospectively attempted PF scanning immediately after AF scanning and by the same operator on (172) occasions for (133) neonates whose mean gestational age at birth was (32.53, ± 5.6 weeks) (range, 22-42 weeks) and whose mean birth weight was (1781.01, ± 1033.3 grams) (range, 520 - 4740grams).
Images were recorded on films or video records for re-evaluation at the end of the study. US is an operator dependant technology. Video records were found to be more informative and increased the diagnostic confidence of examiners than did the US films.
Although AF imaging can be performed with the neonate in any position, imaging through the PF is facilitated by placing the infant in the lateral decubitus position. However, satisfactory images of the occipital horns may be obtained through the posterior aspect of the sagittal suture with the infant in the supine position.
Coronal and sagittal views through the PF can be standardized in the same way as in AF study and add approximately 5 minutes to the examination.
Brain structures that are particularly well depicted with the PF approach include the occipital lobes, the occipital horns, the glomus of the choroid plexus, the brain stem, the cerebellum, the fourth ventricle and the basal cisterns.
Sonograms obtained via the posterior fontanelle were satisfactory for (95 %) of neonates born at or less than 34 weeks gestation and for (92%) of all neonates scanned.
The mean age at birth of those with satisfactory sonograms obtained via the posterior fontanelle was 32.58±5.56 weeks; in comparison, a mean age at birth of 36.7±2.56weeks was associated with unsatisfactory sonograms (p< .005). In general, neonates for whom PF sonograms were unsatisfactory were older.
Accurate diagnosis of IVH facilitates appropriate management of each neonate, including enrollment in early intervention programs. In our study, PF scanning increases the examiner’s confidence in diagnosing IVH.
Our study showed increase in the rate of detection of IVH by 34% (from 30 to 46 cases) by adding PF scanning to the traditional AF scanning technique.
There was no statistically significant difference between the mean gestational age and the mean birth weight of premature newborns with IVH diagnosed via AF approach and those with IVH diagnosed via PF approach. However there was highly statistically significant role of PF sonography in diagnosing grade II-IVH with normal size ventricles. (p=0.0003)
As expected, the appearances of IVH seen via the PF are similar to those of IVH seen via the AF sonography. But in our study, a blood-CSF layer was seen in 5 (31%) out of the 16 cases of IVH diagnosed via PF sonography.
PF was the only view to diagnose posterior fossa hemorrhage including cerebellar hemorrhage and hemorrhage extending to the fourth ventricle.
When US scanning was performed using the PF as an acoustic window, the lack of visualization of the supratentorial structures and frontal region was the reason for the non visualization of germinal matrix and frontal parenchymal hemorrhages as well as hemorrhages extending to the third ventricle.
A major purpose of neonatal cranial US is to identify neonates at high risk and, equally important, neonates at low risk for neurologic impairment. Clear visualization of the choroid glomus on PF sonography allows differentiation of IVH from bulky or lobulated choroids or when calcar avis created a pseudomass.
PF sonography also provided useful diagnostic information on congenital malformations especially abnormalities of the posterior fossa ;
• It allows better visualization of the fourth ventricle thereby determining the type of congenital Hydrocephalus with grater confidence.
• PF was the only view to diagnose Arnold Chiari malformation in cases of neural tube defects. PF clearly shows small posterior fossa, elongated or obliterated fourth ventricle and in some instances herniation of cerebellum into the foramen magnum could be identified.
• It plays a major role in differentiating posterior fossa cyst from true Dandy-Walker malformation due to excellent visualization of cerebellar vermis, fourth ventricle and cisterna magna.
• It play a role in differentiating types of Holoprosencephaly by identifying the cleavage of the lateral ventricles and identifying the falks posteriorly which are both characteristic of lobar Holoprosencephaly.
PF sonography also provided useful diagnostic information on vascular, infection and hypoxic brain lesions among studied newborn infants. Further larger studies on a wider scale are recommended to highlight the role of PF sonography in diagnosing these neonatal intracranial lesions.
The advantages of posterior fontanelle scanning include:
• better visualization of the occipital horns.
• clear visualization of calcarine fissure pseudomass.
• better differentiation of blood-filled ventricles from surrounding brain.
• clear images of the choroids plexus at the trigone of lateral ventricles.
• clear visualization of posterior fossa structures namely; the cerebellum, fourth ventricle , brain stem ,basal cisterns and cisterna magna.
The disadvantages include:
• it is technically more difficult to perform, especially in the term infants or sick, unstable newborns nursed in supine position.
• the inability to diagnose germinal matrix hemorrhage.
• the lack of visualization of the frontal horns of lateral ventricles (unless they are dilated)
• the lack of visualization of the supratentorial compartment and the frontal parenchymal brain region.
Neonatologists should be aware that there will be differences in the diagnosis and interpretation of cranial US examinations according to the available ultrasound technology and expertise.
The potential benefits and harmful consequences of misinterpreting cranial US examinations should be communicated to parents whose infants are undergoing the testing. Infants who have hemorrhagic lesions or any white matter or cystic lesions evident on cranial US examinations require close, systematic follow-up after their discharge from NICU to facilitate the timely initiation of interventions.