Prediction of abnormal neuromotor function by cranial ultrasound
| Cerebral palsy | ||||
|---|---|---|---|---|
| Ultrasound test result | Pre-test probability | Likelihood ratios (95% CI) | Post test probability (95% CI) | Heterogeneity among studies (I2) |
| Normal scan | 9% | 0.5 (0.4 to 0.7) | 5% (4% to 6%) | 90% |
| Grade 1 or 2 IVH | 9% | 1 (0.4 to 3) | 9% (4% to 22%) | 88% |
| Grade 3 IVH | 9% | 4 (2 to 8) | 26% (13% to 45%) | 82% |
| Grade 4 haemorrhage (any) | 9% | 11 (4 to 31) | 53% (29% to 76%) | 84% |
| Cystic PVL | 9% | 29 (7 to 116) | 74% (42% to 92%) | 90% |
| Ventricular dilatation | 9% | 3 (2 to 4) | 22% (17% to 28%) | 0% |
| Hydrocephalus | 9% | 4 (1 to 13) | 27% (10% to 56%) | 97% |
Normal scan refers to absence of haemorrhage within the brain parenchyma or ventricles, cysts or ventricular dilation. The grade of IVH (intraventricular haemorrhage) is given according to the Papile classification. PVL indicates periventricular leukomalacia. Ventricular dilation indicates moderate to severe ventricular dilation not meeting the criterion for hydrocephalus. Hydrocephalus indicates massive ventricular dilation >4 mm above the 97th centile. Pre-test probability refers to the prevalence of cerebral palsy based on the Epipage study.4 The likelihood ratio is the probability that a patient with cerebral palsy has a positive test (abnormal ultrasound result). Post-test probability is the probability that a patient with a specific abnormality on cranial ultrasound will have abnormal neuromotor function. Heterogeneity is a measure of similarity between studies and the validity of statistical pooling.