Radiology
MRI uses strong magnetic fields to align atomic nuclei (usually hydrogen protons) within body tissues, then uses a radio signal to disturb the axis of rotation of these nuclei and observes the radio frequency signal generated as the nuclei return to their baseline states. The radio signals are collected by small antennae, called coils, placed near the area of interest. An advantage of MRI is its ability to produce images in axial, coronal, sagittal and multiple oblique planes with equal ease. MRI scans give the best soft tissue contrast of all the imaging modalities. With advances in scanning speed and spatial resolution, and improvements in computer 3D algorithms and hardware, MRI has become an important tool in musculoskeletal radiology and neuroradiology.
Prostate cancer screening
Transrectal ultrasonography (TRUS) has the advantage of being fast and minimally invasive, and better than MRI for the evaluation of superficial tumor. It also gives details about the layers of the rectal wall, accurate and useful for staging primary rectal cancer. While MRI is better in visualization of locally advanced and stenosing cancers, for staging perirectal lymph nodes, both TRUS and MRI are capable. TRUS has a small field of view, but 3D TRUS can improve the diagnosis of anorectal diseases.