A widened lateral ventricle with a normal MRI is fine in most cases. For cases where widening of the lateral ventricles is found, an MRI of the head is an important test to rule out some structural and functional abnormalities. However, if the MRI is normal, it does not necessarily mean that there is no problem. Because some causes of lateral ventricular widening may not be fully identified by MRI, other tests need to be performed, or the patient may need to be followed up dynamically. Lateral ventricular widening can be caused by normal variants, structural abnormalities (e.g., hypoplasia of the corpus callosum, etc.), space-occupying lesions (e.g., congenital cysts and masses), or physiologic brain atrophy, etc. If the MRI of the head is normal, at least the lateral ventricles may be widened. If the head MRI is clean, at least it can be relatively reassuring. Later on, MRI or regular ultrasound follow-up is also required, and in some patients, chromosomal tests, etc. are needed.