Which imaging modality is least useful in a case of CNS neoplasm?

Ans BHere the doubt is between Radiographs and USG. But in CNS tumours radiographs can show many direct and indirect signs like calcification, bone erosion, hyperostosis, widening of various intracranial foramina, features of raised ICT. But ultrasound simply cannot penetrate the skull and is useful only in children when the fontanelles are open.