Editing Radiology (section)

=== Magnetic resonance imaging ===
{{main|Magnetic resonance imaging}}
[[File:MRI knee abdonrmal.jpg|thumb|MRI of the knee]]

MRI uses strong magnetic fields to align [[atomic nucleus|atomic nuclei]] (usually [[hydrogen]] [[proton]]s) 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.<ref>{{cite web |title=Magnetic Resonance, a critical peer-reviewed introduction |publisher=European Magnetic Resonance Forum |access-date=16 November 2014 |url=http://www.magnetic-resonance.org/ |archive-date=8 September 2013 |archive-url=https://web.archive.org/web/20130908054907/http://www.magnetic-resonance.org/ |url-status=live }}</ref>  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 [[Transverse plane|axial]], [[Coronal plane|coronal]], [[Sagittal plane|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.{{citation needed|date=May 2024}}

One disadvantage is the patient has to hold still for long periods of time in a noisy, cramped space while the imaging is performed. Claustrophobia (fear of closed spaces) severe enough to terminate the MRI exam is reported in up to 5% of patients. Recent improvements in magnet design including stronger magnetic fields (3 [[tesla (unit)|teslas]]), shortening exam times, wider, shorter magnet bores and more open magnet designs, have brought some relief for claustrophobic patients. However, for magnets with equivalent field strengths, there is often a trade-off between image quality and open design. MRI has great benefit in imaging the brain, spine, and musculoskeletal system. The use of MRI is currently contraindicated for patients with pacemakers, cochlear implants, some indwelling medication pumps, certain types of cerebral aneurysm clips, metal fragments in the eyes, some metallic hardware due to the powerful magnetic fields, and strong fluctuating radio signals to which the body is exposed. Areas of potential advancement include functional imaging, cardiovascular MRI, and MRI-guided therapy.