Cardiac imaging
"Magnetic resonance imaging" (originally called nuclear magnetic resonance imaging), an imaging methodology based on aligning the spin axis of nuclei within molecules of the object being visualized using both powerful superconducting magnets and radio frequency and detectors. Cardiology uses are growing, especially since MRI differentiates soft tissues better than CT and allows for comprehensive exams including the quantitative assessment of size, morphology, function, and tissue characteristics in one single session. Current implementations for Cardiology uses are sometimes limited by lengthy protocols, claustrophobia and contraindications based on some complex metallic implants (pacemakers, defibrillators, insulin pumps), while artificial valves and coronary stents are generally not problematic. Image quality can be reduced by the continuous movement of heart structures. There is a promising future in cardiac MRI by more efficient scans, increasing availability of scanners and more widespread knowledge about its clinical application.
Low back pain
Imaging is indicated when there are red flags, ongoing neurological symptoms that do not resolve, or ongoing or worsening pain. In particular, early use of imaging (either MRI or CT) is recommended for suspected cancer, infection, or cauda equina syndrome. MRI is slightly better than CT for identifying disc disease; the two technologies are equally useful for diagnosing spinal stenosis. Only a few physical diagnostic tests are helpful. The straight leg raise test is almost always positive in those with disc herniation. Lumbar provocative discography may be useful to identify a specific disc causing pain in those with chronic high levels of low back pain. Similarly, therapeutic procedures such as nerve blocks can be used to determine a specific source of pain. Some evidence supports the use of facet joint injections, transforminal epidural injections and sacroilliac injections as diagnostic tests. Most other physical tests, such as evaluating for scoliosis, muscle weakness or wasting, and impaired reflexes, are of little use.