Diffusion-weighted imaging of the brain in preterm infants with focal and diffuse white matter abnormality.
OBJECTIVE
The most common finding on magnetic resonance imaging (MRI) of the brain in preterm infants at term-equivalent age is diffuse excessive high signal intensity (DEHSI) in the white matter. It is unclear whether DEHSI represents a biological abnormality. This study used diffusion-weighted imaging (DWI) to compare apparent diffusion coefficient (ADC) values in DEHSI with infants with normal imaging and those with overt brain damage to determine whether DEHSI shows the diffusion characteristics of normal or abnormal tissue.


METHODS
MRI, using conventional and diffusion-weighted imaging (DWI), was performed in 50 preterm infants at term-equivalent age using a 1.5 Tesla MR scanner. The infants were divided into 3 groups on the basis of their MRI results: 1) normal white matter, 2) DEHSI, or 3) overt white matter pathology. ADC values were measured in the frontal, central, and posterior white matter at the level of the centrum semiovale. ADC values in the 3 groups of preterm infants were compared using a 1-way analysis of variance with a Bonferroni test for multiple comparisons.


RESULTS
ADC values were significantly higher in infants with DEHSI and infants with overt white matter pathology than in infants with normal white matter. There was no significant difference between ADC values in infants with DEHSI and those with overt white matter pathology.


CONCLUSIONS
This study provides objective evidence that DEHSI represents diffuse white matter abnormality.
Counsell
Serena J
SJ
Robert Steiner Magnetic Resonance Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Campus, London, United Kingdom.
Allsop
Joanna M
JM
Harrison
Michael C
MC
Larkman
David J
DJ
Kennea
Nigel L
NL
Kapellou
Olga
O
Cowan
Frances M
FM
Hajnal
Joseph V
JV
Edwards
A David
AD
Rutherford
Mary A
MA
D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000473:pathology*; D004058:Diffusion; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007969:Leukomalacia, Periventricular / Q000378:metabolism / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*