Optic Nerve Sheath Diameter in Preterm Infants: Suggested Values.

OBJECTIVE Timely detection of elevated intracranial pressure (ICP) in highrisk preterm infants may be critical to avoid permanent neurologic sequelae. Size of optic nerve sheath diameter (ONSD) is highly correlated with changes in ICP. Normal ultrasonographic ONSD values for preterm infants have been published. This study sought to compare these data with MRI measured OSND and to propose suggested ultrasonographic ONSD values. METHODS The ONSD in preterm MRIs were retrospectively measured and related to pre-existing ultrasonographic ONSD. Data were stratified for corrected gestational age. Simple linear regression between ONSD mean values and age was modeled for both eyes, and R2 was calculated. Suggested values for ultrasonographic ONSD were ascertained through linear regression and calculated prediction intervals. RESULTS ONSD measurements demonstrated R2 values of 0.95 (right ONSD MRI), 0.95 (left ONSD MRI), 0.96 (right ONSD ultrasound), and 0.93 (left ONSD ultrasound). Suggested ONSD values were incremental with corrected gestational age. CONCLUSION ONSD measurements with MRI and ultrasound are similar. The proposed suggested ONSD values may be helpful in clinical situations where ICPs are suspected or known.