Assessment of Cranial Sonographic Findings of Hypoxic Ischemic Brain Injury in Perinatal Asphyxia

Background: In perinatal asphyxia, hypoxic ischemic brain injury remains most serious condition causing significant mortality and long term morbidity. Early detection of intracranial changes and its consequences will enhance timely intervention and better out come. Cranial sonography can be done to assess the abnormalities of brain in perinatal asphyxia. Objectives: The objective of this study was to evaluate usefulness of cranial sonography in perinatal asphyxia. Methods: This was an observational study conducted from March 2014 to February 2015 at department of radiology and imaging, Enam Medical College and Hospital. Total 100 neonates with perinatal asphyxia were included in this study. Cranial USG was done in all cases and sonographic abnormalities were evaluated. Result: 56 term (>37 weeks of gestation ) and 44preterm (<37 weeks of gestation ) newborn having birth asphyxia were taken as cases in this study. Common cranial sonographic findings of preterm babies were periventricular leukomalacia 29% (13), germinal matrix hemorrhage 14% (6), Intraventricular hemorrhage 11% (5) cerebral oedema 7% (3) and normal 39% (17). Common cranial USG findings in term babies were cerebral oedema 43% (24), intracerebral hemorrhage 5% (3), Focal cerebral infarct 4% (2), Intraventricular hemorrhage 2% (1) and normal 46% (26). Conclusion: This study found that transcranial sonography is useful to identify the abnormalities in brain of asphyxiated neonate and helps to predict the neurodevelopmental outcome. So proper management plan can be done.

ultimately results in immediate and delayed form of neuronal death. 4So it is important to assess the severity of asphyxia to give adequate treatments and prevent brain damage.Cerebral sonography in neonatal period can assess the abnormality of brain caused by asphyxia and provide early guide to the neurodevelopmental prognosis.
Cranial ultrasound was first introduced in 1979 in neonatal care units to detect intracranial pathology. 5,6The development of high resolution, real time sector together with increasing expertise in its use and interpretation of finding, has established the role of sonography in the analysis of neonatal brain.Cranial ultrasound has become an essential diagnostic tool in modern neonatology for depicting normal anatomy and pathological changes in neonatal brain.
Because in the neonate many sutures and fontanels are still open and these can be used as acoustic window to look into the brain. 7It is also cost effective, radiation free and its safety is well established in infants. 8Now a day cranial ultrasound has been used routinely for infants at risk of neurological impairment such as who have suffered from birth asphyxia.This study was conducted to assess the cranial sonographic findings in neonates with perinatal asphyxia.

Materials and methods:
This Descriptive statistical analysis of all information and data was carried out.

Results:
One hundred newborn were enrolled in this study.Among them 44 babies were preterm and 56 babies were term with perinatal asphyxia.Mode of delivery was normal vaginal delivery for 46% neonates and 54% via LUCS for various reasons.There were 52% female and 48% were male neonates (Table I).

Birth weight
No. of the Percentage respondents 2.5 -3.5 kg 40 71% >3.5 -4 kg 16 29% 12% mother had premature rupture membrane, l2% had APH, 8% pre-eclamptic toxemia and hypertension, 6 % had Diabetes mellitus and 4% had oligohydramnios during pregnancy (Table VII) In 56 term asphyxiated newborn, 24 (43%) showed cerebral oedema, 3 (5%) showed intracerebral hemorrhage, 2 (4%) showed Focal cerebral infarct, 1 (2%)showed IVH, and 26 (46%) showed normal findings (Table X).Although there is great improvement in perinatal practice, the mortality and incidence of cerebral palsy caused by asphyxia have remained unchanged partly because of the absence of early diagnosis and identification methods.Due to wide availability of ultrasound machines and other advantages like, it is cheap, easy to perform, non-invasive and can be initiated at a very early stage, even immediately after birth,ultrasound has been used extensively in neonates to evaluate neonatal brain in perinatal asphyxia.This study explores early diagnostic value of cranial sonogram to identify abnormalities in perinatal asphyxia.

Table-X USG findings in
In our study there were 52% female and 48% male out of one hundred newborn of which 44 were preterm and 56 were term.Most of the studies also showed that birth asphyxia is more common in full term rather than preterm babies. 9,10This study shows that majority (68%) of the preterm babies were more than 2 kg to less than 2.5 kg weight group and majority (71%) of the term babies were of 2.5 to 3.5 kg weight group.This figures correlate well with the studies of Barr and Dipietro et al. 11,12 In our study common clinical presentations were 75% respiratory distress, 42% convulsion, 40% cyanosis, 30(30%) apnoeic spell and 12% sepsis which were near consistent with other studies. 11,13,14,15Respiratory distress was the most common findings (75%) in this study.Martin et al found respiratory distress in 48.4% cases in his study. 14Convulsion is also an important presentation in this study, about 42%.Result of Finer et al 16 and Goldberg et al 10 are near consistent with this study.Cyanosis in this study was found in 40% cases which is also consistent with other study. 13,14rinatal risk factors were 12% premature rupture membrane, l2% APH, 8% pre-eclamptic toxemia and hypertension, 6 % Diabetes mellitus and 4% oligohydramnios.Other studies were also consistent with the present study. 14,17n preterm asphyxiated baby common sonographic finding is periventricular leukomalacia(PVL) which appear on ultrasound as increased echogenicity in perventricular region.In preterm neonate perventricular region is watershed zone and relatively hypovascular that's play a role in development of PVL.But with maturity of infant watershed zone shifts from periventricular region to a more peripheral location and PVL is less common and cranial ultrasound most commonly shows pattern of diffuse cerebral oedema in term neonate seen as diffuse increased echogenicity of brain with obliterated CSF spaces.In preterm neonate highly vascular germinal matrix is the site of hemorrhage, intraventricular hemorrhage (IVH) may also occur either from rupture of germinal matrix hemorrhage (GMH) or from choroid plexus bleeding.In term neonate germinal matrix is involutes so hemorrhage is uncommon here but intraventricular hemorrhage has been reported from choroid plexus.

Conclusion:
This study found that cranial USG is a reliable technique for demonstrating the most frequently occurring forms of cerebral injury in perinatal asphyxia, assessing the evolution of the lesion, and following brain development.Our study reveals that PVL, germinal matrix hemorrhage and IVH are common sonogrphic findings in preterm neonates and that of term neonates is cerebral oedema.As cranial sonography is an noninvasive diagnostic technique, simultaneously efficient, effective and safe modality, it can be used as a valuable diagnostic tool and predictor of outcome of hypoxic ischemic brain injury.
Among the preterm babies, highest number 26 (59%) were in the age group of 34-36 weeks of gestational age and among the term babies, highest number 38 (68%) were in the age group of 37-39 weeks of gestational age (Table III & IV).

Table - VII
Perinatal risk factors for asphyxia of newborns (n = 100)