Comparison of Spin-Echo T1- and T2-Weighted and Gradient-Echo T1-Weighted Images at 3T in Evaluating Very Preterm Neonates at Term-Equivalent Age

GRE-T1WI (A), SE-T1WI (B), and SE-T2WI (C) at the level of the pontomesencephalic junction in a very preterm infant (26 weeks +5 days at birth), imaged at term-equivalent age (39 weeks +5 days). The medial lemniscus (ML) (arrows) and the lateral lemniscus (dashed arrows) are well-depicted on both GRE-T1WI and SE-T2WI but not on SE-T1WI. These 2 structures were myelinated on both sequences in the large majority of term-equivalent infants. A level just caudal to that (D–F) demonstrates that the ML is well-visualized on each sequence, while the cranial nerve V fascicle (thin arrows) is well-visualized on both GRE-T1WI and SE-T2WI but not on SE-T1WI.

Comparison among GRE-T1WI (A), SE-T1WI (B), and SE-T2WI (C) at the level of the midbrain in a very preterm infant (26 weeks +0 days) imaged at term-equivalent age (40 weeks +1 day). The DSCP (arrows) and the brachium of the inferior colliculus (dashed arrows) are depicted. The DSCP was myelinated in all term-equivalent infants on both GRE-T1WI and SE-T2WI, while the brachium of the inferior colliculus was variably myelinated on these 2 sequences.

GRE-T1WI (A and C) and SE-T2WI (B and D) at the level of the medulla in a very preterm infant (26 weeks +0 days) imaged at term-equivalent age (40 weeks +1 day). Regarding A and B, the spinal tract and nucleus of cranial nerve V (STV) (arrows) are more easily delineated on SE-T2WI, while the pyramidal decussation (PD) (dashed arrows) is visible on both sequences. Note the cuneate fasciculi (arrowheads) just medial to the STV. At a level 1 section higher (C and D), the ICP (thin arrows) and the PD (dashed arrows) are visible on both sequences, but the ICP is more clearly visible on SE-T2WI due to a greater contrast with the remainder of the medulla.