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Serial magnetic resonance imaging and proton spectroscopy in hypoxic-ischaemic encephalopathy
NeonatalSociety Abstracts/Early Hum. Dev. 35 (1993) 221-234
225
We report a study using Doppler ultrasound to measure cerebral blood flow velocities (CBFV) as an indication of alterations in cerebral haemodynamics. CBFV were recorded on a beat-to-beat basis over 60 s epochs. The CPP was altered during the epoch by rapidly altering the infants’ posture from horizontal to either 20” head up or head down. An informative response was considered to be, either a uniphasic, immediate alteration in velocity occurring with the change in posture and without a subsequent change; or a biphasic response of an initial change in CBFV followed within 20 s by a second response. The latter is considered to be consistent with autoregulatory activity within the strict definition of the term. A total of 501 epochs in 60 neonates of gestational age range 24 to 41 weeks were analyzed. It was shown that any one individual could make either response but the reliability of making an active, biphasic response increased with increasing gestational age and would be in keeping with a maturing development.
Serial magnetic resonance imaging and proton spectroscopy in hypoxic-ischaemic encephalopathy. M.A. Rutherforda, F.M. Cowana, I.J. Coxb, G.A. Couttsb, J. Sargentonib, D. Bryantb, J. Pennockb, G. Bydderb, L. Dubowitza, ‘Department of Paedia tries, bDepartment of Magnetic Resonance Imaging, Hammersmith Hospital, Du Cane Road, London W12 OHS, UK.
We examined two neonates with severe hypoxic-ischaemic encephalopthy with magnetic resonance imaging (MRI) and proton spectroscopy (1H MRS) on several occasions during the first weeks of life. A I-Tesla Picker magnet was used to obtain Tl weighted inversion recovery and T2 weighted spin echo images. A 1.5Tesla Picker prototype magnet was used for spectroscopy. Results: Case 1 had a featureless scan on day 3 with bilateral high signal areas in the basal ganglia and thalami suggesting haemorrhagic infarction. By day 10 the cortex was visible and was abnormally ‘highlighted’. Two weeks later there were multiple areas of low signal consistent with cyst formation in the basal ganglia and there were linear areas of low signal consistent with subcortical infarction. Ultrasound scan had shown densities in the region of the thalami without other abnormalities. Proton spectroscopy revealed widespread lactate peaks on day 7 which were still present in the region of the basal ganglia on day 28. Case 2 had a featureless scan on day 3. On day 7 widespread cortical highlighting was noted. There was a small high signal area in the right lentiform nucleus. Two weeks later there were marked areas of low signal subcortically. Ultrasound showed mild densities within the thalami without other abnormalities. Proton spectroscopy on day 3 showed lactate in several areas of the brain. These two cases illustrate the ability of MRI, as compared with ultrasound, to detect and follow the evolution of severe cortical lesions associated with HIE. In addition the finding of lactate in multiple areas of the brain appears to be an early marker for permanent tissue injury, at a time when the N-acetylaspartatelcholine ratio was normal.
225
We report a study using Doppler ultrasound to measure cerebral blood flow velocities (CBFV) as an indication of alterations in cerebral haemodynamics. CBFV were recorded on a beat-to-beat basis over 60 s epochs. The CPP was altered during the epoch by rapidly altering the infants’ posture from horizontal to either 20” head up or head down. An informative response was considered to be, either a uniphasic, immediate alteration in velocity occurring with the change in posture and without a subsequent change; or a biphasic response of an initial change in CBFV followed within 20 s by a second response. The latter is considered to be consistent with autoregulatory activity within the strict definition of the term. A total of 501 epochs in 60 neonates of gestational age range 24 to 41 weeks were analyzed. It was shown that any one individual could make either response but the reliability of making an active, biphasic response increased with increasing gestational age and would be in keeping with a maturing development.
Serial magnetic resonance imaging and proton spectroscopy in hypoxic-ischaemic encephalopathy. M.A. Rutherforda, F.M. Cowana, I.J. Coxb, G.A. Couttsb, J. Sargentonib, D. Bryantb, J. Pennockb, G. Bydderb, L. Dubowitza, ‘Department of Paedia tries, bDepartment of Magnetic Resonance Imaging, Hammersmith Hospital, Du Cane Road, London W12 OHS, UK.
We examined two neonates with severe hypoxic-ischaemic encephalopthy with magnetic resonance imaging (MRI) and proton spectroscopy (1H MRS) on several occasions during the first weeks of life. A I-Tesla Picker magnet was used to obtain Tl weighted inversion recovery and T2 weighted spin echo images. A 1.5Tesla Picker prototype magnet was used for spectroscopy. Results: Case 1 had a featureless scan on day 3 with bilateral high signal areas in the basal ganglia and thalami suggesting haemorrhagic infarction. By day 10 the cortex was visible and was abnormally ‘highlighted’. Two weeks later there were multiple areas of low signal consistent with cyst formation in the basal ganglia and there were linear areas of low signal consistent with subcortical infarction. Ultrasound scan had shown densities in the region of the thalami without other abnormalities. Proton spectroscopy revealed widespread lactate peaks on day 7 which were still present in the region of the basal ganglia on day 28. Case 2 had a featureless scan on day 3. On day 7 widespread cortical highlighting was noted. There was a small high signal area in the right lentiform nucleus. Two weeks later there were marked areas of low signal subcortically. Ultrasound showed mild densities within the thalami without other abnormalities. Proton spectroscopy on day 3 showed lactate in several areas of the brain. These two cases illustrate the ability of MRI, as compared with ultrasound, to detect and follow the evolution of severe cortical lesions associated with HIE. In addition the finding of lactate in multiple areas of the brain appears to be an early marker for permanent tissue injury, at a time when the N-acetylaspartatelcholine ratio was normal.