MRI Questions

My 16 month old son had an MRI due to his short stature and developmental delays.  The MRI was ordered by son's endocrinologist, who recently mailed us the results.  Based on the findings, he has referred us to a pediatric neurologist.  Our appointment, however, is over 3 months away, so I am hoping someone can help us make sense of the report that was sent to us.

The report states that "there is mild ventriculomegaly involving the lateral and third ventricles, as well as dilated sulci/subarachniod spaces and macrocephaly.  In addition, the white matter myelination pattern is still quite incomplete and is slightly delayed for age . . . there is slight inferior ectopia of the cerebellar tonsils, with anatomic crowding at the foramen magnum."

I am very worried about our son and what this all means for him.  And there is the scary question of what caused this.  We know that our son also has low IGF-1, which I am learning is very critical to brain development.  Is low IGF-1 the cause or is it yet another symptom of a larger problem?  

Helping us understand the MRI findings would mean a great deal to us.