Counsell Serena J, Kennea Nigel L, Herlihy Amy H, Allsop Joanna M, Harrison Michael C, Cowan Frances M, Hajnal Joseph V, Edwards Bridget, Edwards A David, Rutherford Mary A
Robert Steiner MR Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Campus, Imperial College, DuCane Road, London, England.
AJNR Am J Neuroradiol. 2003 Sep;24(8):1654-60.
MR imaging is increasingly used to assess maturation and disease in the preterm brain. Knowledge of the changes in T2 values with increasing postmenstrual age (PMA) will aid image interpretation and help in the objective assessment of maturation and disease of the brain in infants. The aim of this study was to obtain T2 values in the preterm brain from 25 weeks' gestational age (GA) until term-equivalent age in infants who had normal neurodevelopmental findings at a minimum corrected age of 1 year.
The study group consisted of 18 preterm infants, born at 33 weeks' GA or sooner. The median GA of the infants at birth was 27 weeks (range, 23-33 weeks), and the median PMA at imaging was 31 weeks (range, 25-41 weeks). T2 measurements were obtained using a 1.0-T MR system and a four-echo pulse sequence (TR/TE, 2500/ 30, 60, 110, and 600). T2 values were measured in the thalami, lentiform nuclei, frontal white matter, occipital white matter, and central white matter at the level of the centrum semiovale.
A significant negative linear correlation between T2 values and PMA was demonstrated in the lentiform nuclei (P =.003), frontal white matter (P <.0001), occipital white matter (P <.0001), and central white matter at the level of the centrum semiovale (P <.0001). T2 values were not significantly reduced with increasing PMA in the thalami (P =.06).
T2 values decrease with increasing PMA in the preterm brain.
磁共振成像（MR成像）越来越多地用于评估早产儿脑的成熟度和疾病情况。了解随着孕龄（PMA）增加T2值的变化，将有助于图像解读，并有助于对婴儿脑的成熟度和疾病进行客观评估。本研究的目的是获取孕龄25周（GA）至足月等效年龄的早产儿脑的T2值，这些婴儿在至少1岁的校正年龄时神经发育结果正常。
研究组由18名早产儿组成，出生时孕龄为33周或更早。婴儿出生时的中位孕龄为27周（范围23 - 33周），成像时的中位PMA为31周（范围25 - 41周）。使用1.0-T MR系统和四回波脉冲序列（TR/TE，2500/30、60、110和600）进行T2测量。在半卵圆中心水平的丘脑、豆状核、额叶白质、枕叶白质和中央白质中测量T2值。
在豆状核（P = 0.003）、额叶白质（P < 0.0001）、枕叶白质（P < 0.0001）和半卵圆中心水平的中央白质（P < 0.0001）中，T2值与PMA之间呈现显著的负线性相关。在丘脑中，T2值并未随着PMA的增加而显著降低（P = 0.06）。
在早产儿脑中，T2值随着PMA的增加而降低。
