Periventricular leukomalacia (PVL) is a common and serious sequela of white matter damage (WMD) in preterm infants, and is also the main cause of cerebral palsy in children, with an incidence of about 3-9%. Some children have a clear history of hypoxia and asphyxia. Clinical manifestations: language impairment, mental retardation, epilepsy, behavioral abnormalities, autism and deafness. 1.Pathological basis of PVL PVL is a periventricular white matter injury caused by hypoxia and ischemia of brain tissue, softening of brain tissue, cystic degeneration, peripheral gliosis, collapse of cystic cavity, reduction of cerebral white matter volume, destruction of ventricular canal membrane and integration of cystic cavity into the ventricle resulting in irregular dilatation of the ventricle. According to the pathological changes, PVL can be divided into focal PVL and diffuse PVL. 2. Diagnostic imaging methods Cranial CT and cranial MRI imaging are the most common diagnostic imaging methods for PVL. Compared with CT, MRI has the advantages of no radiation, high soft tissue resolution and no bone artifacts. The child was routinely given 10% chloral hydrate oral solution (0.5-0.7 ml/kg) before the examination, so that the child was examined in the sleep state. Routine scan sequences T1WI, T2WI, FLAIR axial and a set of sagittal positions. PVL imaging manifestations and diagnosis CT manifestations: patchy and nodular hypointense shadow in the lateral ventricle, irregular enlargement of the lateral ventricle. MRI manifestations: (1) patchy, nodular and striped T1WI low signal, T2WI and FLAIR high signal in the periventricular and hemi-oval brain white matter; (2) reduced volume of the periventricular and hemi-oval brain white matter, enlarged lateral ventricles, ventricular wall edges are not smooth, and the ventricular wall is not clearly demarcated from adjacent lesions; (3) abnormal corpus callosum morphology, the corpus callosum is smaller, thinner or not (4) Diffuse PVL may only show enlargement of the lateral ventricles. The importance of imaging in the diagnosis of PVL Cranial CT and cranial MRI can reveal the location and extent of cranial injury and the distribution of lesions, and can indicate whether there is damage to important structures. In terms of the above two types of examinations, cranial MRI imaging is more comprehensive and accurate in the display of PVL lesions, and is of great value in the diagnosis, differential diagnosis, rehabilitation assessment and prognosis of children with PVL. In areas where conditions are available, it is recommended that cranial MRI examinations be routinely done for children with clinical suspicion of cerebral palsy, motor developmental delay and symptomatic premature infants, so that children with cerebral palsy can be diagnosed early and early This will enable early diagnosis and rehabilitation intervention.