Variability in the diagnostic and management practices of post-hemorrhagic ventricular dilatation in very preterm infants across Canadian centers and comparison with European practices.

OBJECTIVES: To investigate the variability in diagnostic and therapeutic approaches to posthemorrhagic ventricular dilatation (PHVD) among Canadian neonatal centers, and secondary exploration of differences in approaches between Canadian and European practices. METHODS: We conducted a survey among Canadian tertiary neonatal centers on their local practices for managing very preterm infants with PHVD. The survey covered questions on the diagnostic criteria, timing and type of interventions and resources utilization (transfer to neurosurgical sites and neurodevelopmental follow-up). In a secondary exploration, Canadian responses were compared with responses to the same survey from European centers. RESULTS: 23/30 Canadian centers (77%) completed the survey. There was no consensus among Canadian centers on the criteria used for diagnosing PHVD or to initiate intervention. The therapeutic interventions also vary, both for temporizing procedures or permanent shunting. Compared to European practices, the Canadian approach relied less on the sole use of ultrasound criteria for diagnosing PHVD (43 vs 94%, p < 0.0001) or timing intervention (26 vs 63%, p = 0.007). Majority of European centers intervened early in the development of PHVD based on ultrasound parameters, whereas Canadian centers intervened based on clinical hydrocephalus, with fewer centers performing serial lumbar punctures prior to neurosurgical procedures (40 vs 81%, p = 0.003). CONCLUSION: Considerable variability exists in diagnosis and management of PHVD in preterm infants among Canadian tertiary centers and between Canadian and European practices. Given the potential implications of the inter-center practice variability on the short- and long-term outcomes of preterm infants with PHVD, efforts towards evidence-based Canada-wide practice standardization are underway.

Lenticulostriate vasculopathy in very preterm infants.

OBJECTIVE: To assess for lenticulostriate vasculopathy (LSV) on cranial ultrasound (cUS) scans of very preterm infants: incidence and aetiology, evolution during neonatal period, association with clinical parameters, and MRI equivalent. DESIGN: Prospective study. SETTING: Tertiary neonatal referral centre. PATIENTS: Very preterm infants (<32 weeks) underwent sequential cUS throughout the neonatal period and MRI around term age. cUS were evaluated for LSV and other changes, and MRI for changes in signal and myelination in deep grey matter. LSV was divided into early-onset (7 postnatal days). Perinatal clinical parameters were collected for all infants and compared between groups. RESULTS: In 22/111 (20%) infants LSV was detected: early-onset in 5 and late-onset in 17. LSV mostly presented some weeks after birth and persisted for several months. There were no associations between LSV and other changes on cUS or deep grey matter changes on MRI. Infants with late-onset LSV were younger and smaller at birth than infants with early-onset LSV. Postmenstrual age at first detection was comparable for both LSV groups. There were no associations between LSV and perinatal clinical parameters, but infants with LSV had less episodes of hypotension than infants without LSV. CONCLUSIONS: LSV is a frequent finding on cUS in very preterm infants, but does not show on MRI. The postmenstrual age, rather than gestational and postnatal age, seems important in LSV development. LSV is not associated with clinical parameters. When encountered in otherwise healthy preterm infants, LSV is probably a benign temporary phenomenon.

Cranial ultrasound in metabolic disorders presenting in the neonatal period: characteristic features and comparison with MR imaging.

BACKGROUND AND PURPOSE: Brain imaging is an integral part of the diagnostic work-up for metabolic disorders, and the bedside availability of cranial ultrasonography (cUS) allows very early brain imaging in symptomatic neonates. Our aim was to investigate the role and range of abnormalities seen on cUS in neonates presenting with metabolic disorders. A secondary aim, when possible, was to address the question of whether brain MR imaging is more informative by comparing cUS to MR imaging findings. MATERIALS AND METHODS: Neonates with a metabolic disorder who had at least 1 cUS scan were eligible. cUS images were reviewed for anatomic and maturation features, cysts, calcium, and other abnormalities. When an MR imaging scan had been obtained, both sets of images were compared. RESULTS: Fifty-five infants (35 also had MR imaging) were studied. The most frequent findings were in oxidative phosphorylation disorders (21 cUS and 12 MR imaging): ventricular dilation (11 cUS and 6 MR imaging), germinolytic cysts (GLCs; 7 cUS and 5 MR imaging), and abnormal white matter (7 cUS and 6 MR imaging); in peroxisomal biogenesis disorders (13 cUS and 9 MR imaging): GLCs (10 cUS and 6 MR imaging), ventricular dilation (10 cUS and 5 MR imaging), abnormal cortical folding (8 cUS and 7 MR imaging), and lenticulostriate vasculopathy (8 cUS); in amino acid metabolism and urea cycle disorders (14 cUS and 11 MR imaging): abnormal cortical folding (9 cUS and 4 MR imaging), abnormal white matter (8 cUS and 8 MR imaging), and hypoplasia of the corpus callosum (7 cUS and 6 MR imaging); in organic acid disorders (4 cUS and 2 MR imaging): periventricular white matter echogenicity (2 cUS and 1 MR imaging); and in other disorders (3 cUS and 1 MR imaging): ventricular dilation (2 cUS and 1 MR imaging). cUS findings were consistent with MR imaging findings. cUS was better for visualizing GLCs and calcification. MR imaging was more sensitive for subtle tissue signal intensity changes in the white matter and abnormality in areas difficult to visualize with cUS, though abnormalities of cortical folding suggestive of polymicrogyria were seen on cUS. CONCLUSION: A wide range of abnormalities is seen using cUS in neonatal metabolic disorders. cUS is a reliable bedside tool for early detection of cysts, calcium, structural brain abnormalities, and white matter echogenicity, all suggestive of metabolic disorders.

Differentiating normal myelination from hypoxic-ischemic encephalopathy on T1-weighted MR Images: a new approach.

BACKGROUND AND PURPOSE: Hypoxic-ischemic cerebral changes can be difficult to distinguish from normal myelination on T1-weighted images. We hypothesized that comparing signal intensity (SI) of brain structures on T1-weighted images enables differentiation of myelination from hypoxic-ischemic brain damage. MATERIALS AND METHODS: T1-weighted images, obtained in 57 infants aged 1-104 days and born after a gestational age of 35 weeks or older, were retrospectively evaluated. Subjects were assigned to a patient (n = 23, with perinatal hypoxic-ischemic encephalopathy [HIE] stage 2/3) or a control group (n = 34). In each subject, an SI score was assigned to 19 brain structures on the basis of pairwise comparisons with the other 18 structures. In both groups, mean total SI scores were calculated for the 19 structures. Independent samples t tests assessed whether the mean total score of a structure differed significantly between the 2 groups. Logistic regression assessed which comparison was best to distinguish between the groups and to predict the presence of hypoxic-ischemic injury. RESULTS: In patients, mean total SI scores for posterolateral putamen (PP) and peri-Rolandic cortex (PC) were significantly higher (P = .000 for both). Mean total SI scores of the posterior limb of internal capsule (PLIC) and the corona radiata (CR) were significantly lower in patients (P = .000 and 0.005, respectively). Two comparisons (PLIC versus CR, PP versus PC) were best to distinguish patients and controls and to predict absence or presence of HIE (P < .0001). CONCLUSION: SI changes due to hypoxia-ischemia can be differentiated from normal myelination by comparing SI of 4 brain structures on T1-weighted images.

Prediction of short-term neurological outcome in full-term neonates with hypoxic-ischaemic encephalopathy based on combined use of electroencephalogram and neuro-imaging.

BACKGROUND: In infants with hypoxic-ischaemic encephalopathy (HIE), prediction of the prognosis is based on clinical, neuro-imaging and neurophysiological parameters. METHODS: EEG, cranial ultrasound, MRI and follow-up findings of 23 infants (GA 35-42 weeks) with HIE were studied retrospectively to assess 1) the contribution of ultrasound, MRI and EEG in predicting outcome, 2) the accuracy of ultrasound as compared to MRI, and 3) whether patterns of brain damage and EEG findings are associated. RESULTS: An abnormal EEG background pattern was highly predictive of adverse outcome [positive predictive value (PPV) 0.88]. If combined with diffuse white and deep and/or cortical grey matter changes on ultrasound or MRI, the PPV increased to 1.00. Abnormal neuro-imaging findings were also highly predictive of adverse outcome. Abnormal signal intensity in the posterior limb of the internal capsule, and diffuse cortical grey matter damage were associated with adverse outcome. MRI showed deep grey matter changes more frequently than ultrasound. Severely abnormal neuro-imaging findings were always associated with abnormal EEG background pattern. CONCLUSIONS: Both early EEG and neuro-imaging findings are predictive of outcome in infants with HIE. The predictive value of EEG is strengthened by neuro-imaging.

Hyperechogenicity of the thalamus and basal ganglia in very preterm infants: radiological findings and short-term neurological outcome.

Cerebral ultrasound of preterm infants may show diffuse, bilateral, hyperechogenic "haze" over the thalami and basal ganglia (hyperechogenicity BGT). We explored whether this could be a pathological phenomenon. All cerebral ultrasound examinations performed in 2001 on infants < 35 weeks of age were reviewed. This resulted in a hyperechogenicity and non-hyperechogenicity group. The character of the hyperechogenicity BGT and the presence of concomitant brain lesions were noted. Detailed clinical and follow-up data from a selected group of infants < 32 weeks were reviewed and compared between the 2 groups. The incidence of hyperechogenicity BGT was 11 % (39/359) in infants < 35 weeks and 26 % (37/143) in infants < 32 weeks. Birth weight and gestational age were significantly lower and clinical course was more complicated in the hyperechogenicity group. Concomitant brain lesions were always present. In 12/39 infants with hyperechogenicity BGT, MRI (always performed for other reasons) was available, showing signal intensity changes in thalamic region in 5 infants. The neurological outcome at term was less favorable in the hyperechogenicity group, but similar at 1 year. Thus hyperechogenicity BGT mainly occurred in very small, sick infants and was always associated with cerebral pathology. MRI did not consistently show abnormalities in the thalamic region. It was not associated with a poorer outcome at 1 year.