My understanding is there are three types of biopsy:
Transrectal ultrasound (TRUS) guided biopsy uses ultrasound guidance to place needles through the rectal wall into the gland, typically under a local anaesthetic and utilizing 10-12 needles, half from each side of the gland.
Transperineal mapping biopsy (TMB) uses ultrasound to guide needles placed in a rigid grid into the gland through the transperineum (skin between scrotum and anus). It is done under general anesthesia. Samples are taken every 5mm apart, up to 40-60 samples. This biopsy is not commonly done because general anaesthesia requires an operating room facility.
Magnetic resonance imaging (MRI) guided biopsy ( in real time) uses advanced imaging to reveal the tutor location, size and shape so a doctor can guide a minimum number of needles through the rectal wall into the core of the tutor. It is usually done under a local anesthetic. The doctor can “see” and therefore target needles into the tutor.
My husband had the Transperineal mapping biopsy ( although after an MpMRI three days earlier so the surgeon had something to aim at).
In light of what we now know about the availability of a Magnetic resonance imaging (MRI) guided biopsy we would have gone for that (if available of course).
As Lyn said above re diagnosing my understanding is the same
"Research shows that today’s 3T multi parametric MRI reveals prostate cancer tumours. However, only laboratory analysis under a microscope can give cellular, even molecular, information about the actual tissue samples"