"Although there were no specific features that allowed pre-biopsy diagnosis, gemistocytic astrocytomas were almost always supratentorial and usually located in the frontal lobes 4."
Line 9:58·Only use medical adjectival hyphens where the letters at the end and start of the compound word are the same, e.g. post-transplant. In this case, don't use the hyphen: 'pre-biopsy'.