Age related signal changes of the pituitary stalk on thin-slice magnetic resonance imaging in infants

Signal Intensity and Volume of Pituitary and Thyroid Glands in Preterm and Term Infants

BACKGROUND

Hypothalamic-pituitary-thyroid (HPT) maturation has not been extensively evaluated using neonatal MRI, even though both structures are visualized on MRI.

HYPOTHESIS

That signal intensity and volume of pituitary and thyroid (T) glands on MRI in neonates may be interrelated.

STUDY TYPE

Retrospective.

SUBJECTS

In all, 102 participants.

FIELD STRENGTH/SEQUENCE

3.0T, T₁ -weighted pointwise encoding time reduction with radial acquisition (PETRA).

ASSESSMENT

The volume of interest of the anterior pituitary (AP), posterior pituitary (PP), and T on MRI were defined on T₁ -PETRA by two radiologists, and volumes of AP (AP_vol) and thyroid (T_vol) were calculated. Gestational age (GA), chronological age (CA), GA+CA, birth weight (BW), and thyroid function were recorded. Mean and maximum signal intensities of AP, PP, and T were normalized using signals from the pons and spinal cord as follows: signal ratio of anterior pituitary/pons (AP/pons), signal ratio of posterior pituitary/pons (PP/pons), and signal ratio of thyroid/cord (T/cord) T/cord, respectively.

STATISTICAL TESTS

Correlations between signal intensity and volume measures and GA, CA, GA+CA, and BW were assessed using Pearson's correlation coefficient or Spearman's rank correlation coefficient. Thyroid function analysis and T_mean /cord, T_max /cord, and T_vol were evaluated using the Steel-Dwass test.

RESULTS

AP_mean /pons correlated positively with GA (ρ = 0.62, P < 0.001) and BW (ρ = 0.74, P < 0.001), and negatively with CA (ρ = -0.86, P < 0.001) and GA+CA (ρ = -0.46, P < 0.001). PP_mean /pons correlated positively with GA (ρ = 0.49, P < 0.001) and BW (ρ = 0.63, P < 0.001), and negatively with CA (ρ = -0.70, P < 0.001) and GA+CA (r = -0.38, P < 0.001). T_mean /cord correlated positively with GA (ρ = 0.48, P < 0.001) and BW (ρ = 0.55, P < 0.001), and negatively with CA (ρ = -0.59, P < 0.001) and GA+CA (ρ = -0.22, P = 0.03). AP_vol correlated positively with GA (ρ = 0.68, P < 0.001) and BW (ρ = 0.73, P < 0.001), and negatively with CA (ρ = -0.72, P < 0.001). T_vol correlated positively with GA (ρ = 0.50, P < 0.001) and BW (ρ = 0.61, P < 0.001), and negatively with CA (ρ = -0.54, P < 0.001). AP_mean /pons correlated positively with T_mean /cord (ρ = 0.61, P < 0.001).

DATA CONCLUSION

Signal and volume of pituitary and thyroid glands correlated positively with GA and BW, and negatively with CA in neonates.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY STAGE: 5.