Reproducibility and accuracy of MR imaging of the brain after severe birthasphyxia

BACKGROUND AND PURPOSE: MR imaging of the brain can be used to detect cereb ral damage after suspected hypoxic-ischemic injury, This study examines the reproducibility and accuracy of MR imaging soon after severe birth asphyxi a. METHODS: During a 48-month period, full-term newborn neonates, who died wit hin the first week as a result of severe hypoxic ischemic encephalopathy, w ere included in the study if they had undergone early (<5 days old) MR imag ing and postmortem neuropathologic studies. Two trained observers assessed reproducibility by examining multiple brain regions independently with curr ent criteria and then defining and applying improved criteria. Accuracy of MR findings was tested by comparing the brain regions about which the two i maging raters agreed to those regions about which the two pathologists agre ed, RESULTS: Eight neonates, with a median gestational age of 40 weeks (range, 38-40 weeks) and who suffered severe birth asphyxia, were included in the s tudy, In the reproducibility study, MR imaging agreement was moderate when current criteria were used (k =.44). Using the improved criteria, agreement increased considerably (k =.62), Much of this improvement was due to limit ing the analyses to the posterior limb of the internal capsule, thalamus, p arietal cortex, hippocampus, and medulla, The posterior limb of the interna l capsule was the most reliable region analyzed, MR imaging agreement was s imilar to that achieved by two experienced pathologists reviewing the histo logic sections (k =.66), In the accuracy study, MR imaging abnormality was predictive of pathologic abnormality with a sensitivity of .79 and a positi ve predictive value of 1.0. The predictive value of a single MR imaging abn ormality was .79 (95% confidence interval, .61-.96). CONCLUSION: Criteria that provide substantial reproducibility and accuracy for the interpretation of MR imaging findings very early after birth asphyx ia can be derived.