Approach to differential diagnosis of premature brain periventricular increased echogenicity:
- Periventricular hemorrhage, periventricular leukomalacia, and periventricular edema all appear echogenic in the acute phase on head US. On follow-up head US exams, if the periventricular ecogenicity resolves it can be assumed to be due to edema
- If the periventricular echogenicity starts to cavitate it can be assumed to be due to periventricular hemorrhage or periventricular leukomalacia and then forms a porencephalic cyst that ultimately communicates with the ventricular system, leading to an irregularity in ventricular contour
- In general, periventricular hemorrhage is usually asymmetric and cavitates, periventricular leukomalacia is usually symmetric and cavitates, edema is usually asymmetric and disappears without cavitation
- Occasionally periventricular leukomalacia does not cavitate but results in a diffuse loss of white matter which is best noted on follow-up MRI exam