Early detection of periventricular leukomalacia by diffusion-weighted magnetic resonance imaging techniques

Periventricular leukomalacia (PVL), the principal form of brain injury in t he premature infant, is characterized by overt focal necrotic lesions in pe riventricular white matter and less prominent, more diffuse cerebral white matter injury. The early detection of the latter, diffuse component of PVL is not consistently possible with Conventional brain imaging techniques. We demonstrate the early detection of the diffuse component of PVL by diffusi on-weighted magnetic resonance imaging (DWI). In a premature infant viith n o definite cerebral abnormality detectable by cranial ultrasonography or co nventional magnetic resonance imaging, DWI showed a striking bilateral decr ease in water diffusion in cerebral white matter. The DWI abnormality (ie, decreased apparent diffusion coefficient) was similar to that observed with acute cerebral ischemic lesions in adults. At 10 weeks of age, conventiona l magnetic resonance imaging and ultrasonography showed striking changes co nsistent with PVL, including the presence of small cysts. The observations indicate the importance of DWI in the early identification of the diffuse c omponent of PVL and also perhaps the role of ischemia in the pathogenesis o f the lesion.