Introduction Studies have correlated caudate nucleus (CN) volumes with cognitive scores in very preterm children but it is unclear whether caudate nucleus growth is specifically affected over and above the global impact of prematurity on brain growth.

Objectives To compare the CN volumes, between very preterm and term born controls; to explore the correlation of these values with cognitive function.

Methods 3D MRI images were acquired with MP-RAGE sequence at 1.5T. Manual segmentation of CN volume was performed using MRIcro software. The intra-observer variability of the single analyst was 1.6%. The CN volumes measured were adjusted to total brain volumes using linear regression. Cognitive function was assessed using WISC-IV.

Results 26 preterm children (median GA: 28.2 w) and 15 term controls were studied at a median age of 9.8 years. CN volumes for preterm children were 9.74 ml (SD: 1.14) compared to 10.53 ml (SD:1.33); mean difference (95%CI): 0.79 mls (−0.008 to 1.6); p = 0.052. After adjustment for brain volume, mean difference became 0.69 ml (0.084 to 1.3); p = 0.027. In the preterm group, both original and adjusted CN volumes showed significant correlation with the perceptual reasoning index (p<0.05, r = 0.42 and r = 0.48 respectively) and full scale IQ (p<0.05, r = 0.43 and r = 0.50).

Conclusions After adjustment for the variation in individual brain size, the CN volumes were smaller in very preterm born children. The potential clinical importance of this observation is supported by the correlation of CN volumes with cognitive function.