Temporal evolution of hypoxis-ischaemic brain lesions in asphyxiated full-term newborns as assessed by computerized tomography

Abstract

Hypoxic-ischaemic brain lesions may be detected as low density (LD) areas by means of computerized tomography (CT), but the clinical significance of such LD areas has been controversial. Since timing might be a critical factor, we studied the temporal evolution of LD areas in 9 asphyxiated term babies who had had two or more CT, and compared the changes to the neurodevelopmental outcome. Scans were classified according to the elapsed time after asphyxia as early (day 1-7, n = 6), intermediate (week 2-4, n = 7; week 4-7, n = 3) and late CT (3 months or more, n = 7). In early scans, no, or only ill defined, LD areas were seen in the periventricular region. In intermediate CT's, LD-zones were further diminished in those babies who later were normal. Sharply accentuated LD areas, however, appeared in those who later suffered from neurodevelopmental disorders. These LD areas, probably representing hypoxic-ischaemic lesions, were located periventricularly, extending into the subcortical white matter and the cortex, and usually involved both hemispheres symmetrically. They began to disappear at 4 to 7 weeks in some regions, possibly because of glial proliferation. LD persisting more than 4-7 weeks tended to transform into cyst-like lesions, or marked atrophy. We conclude (1) that hypoxic-ischaemic lesions appear as zones of low density on CT scans performed after the first week and (2) that the extent of such lesions can best be assessed between 9 to 23 days after asphyxia.

Prognostic Value of Neonatal CT Scans in Asphyxiated Term Babies: Low Density Score Compared with Neonatal Neurological Signs

“…When the same Quantitative assessment of LD areas was done on first week CT scans, almost no relationship with the outcome was found. This confirms our previous observation that developmentally relevant hypoxic-ischaemic lesions cannot be detected as LD areas during the first week (Lipp-Zwahlen et al 1985), and explains why Lud~'ig et al (1980) could not find any pathological meaning of LD areas. In the cases presented here, the intermediate CT seems to predict the outcome of asphyxiated babies with great accuracy, much like CT scans done in the second week after stroke in children (Gates et al 1982).…”

“…The exception, who later sufTered from tetraspas- ticity and atethosis, had severe but restricted LD areas that largely spared the cortical rim. The rcason for such a relative-Iy low LD score inspite ofa severe handicap, might be that the CT (from day 29) was done during aperiod in which proliferative repair processes begin to mask the CT-visibility of cortical and white matter lesions, as documented by us elsewhere (Lipp-Zwahlen et al 1985).…”

Prognostic Value of Early MR Imaging in Term Infants with Severe Perinatal Asphyxia

“…sonography (17), near infrared spectroscopy (36), positron emission tomography (33), P-and H-magnetic resonance spectroscopy (2,23,27), ultrasound (3,29) and computed tomography (CT) (1,9,18,19). High sensitivity and specifity of MRI in detecting abnormalities in asphyxiated infants and young children has been demonstrated in several prospective studies (7,12,13,20).…”

Cerebral blood flow velocity pattern in healthy and asphyxiated newborns: a controlled study

“…Therefore we followed prospectively cerebral blood flow velocity in both perinatally asphyxiated and healthy newborns with a gestational age of at least 34 weeks in the first week of life and compared the results of both groups. The infants were matched for birth weight and gestational age.To study our hypothesis that especially cerebral oedema plays an important role in the abnormal changes of cerebral blood flow velocity, we performed serial real-time ultrasonographic and computerized axial tomographic studies (if indicated) of the brain for detection of infarctions, parenchymal haemorrhage and of cerebral oedema [19,31,32,[42][43][44]. …”