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.
Occult fracture
The diagnostic performance of MRI in the detection of occult fractures has been shown to be comparable, or better than MDCT. Indeed, while the specificity of both CT and MRI for the diagnosis of fracture can be as high as 100%, the sensitivity was reported to be higher for MRI. The superiority of MRI over any other imaging modality including MDCT for the detection of occult hip fractures is now recognised. For instance, an occult intertrochanteric extension of a greater trochanter fracture can be most effectively appreciated on MRI Moreover, MRI is extremely helpful in detecting associated soft tissue abnormalities, especially ligamentous lesions. MRI is now considered as the standard in this context. However, because of its relative unavailability in emergency settings and high costs, MRI may only be performed in "high risk patients" with negative X-rays. For example, when a hip occult fracture is suspected, patients with reduced baseline mobility and pain on axial compression are considered at risk and, therefore, should be examined by MRI. MRI signs of occult fractures are evident several weeks before radiographic signs appear. In the hip, a limited and cost effective MR protocol, with only T1 weighted () coronal images, may enable a reliable diagnosis or exclusion of occult fracture in very little time, for example, 7 minutes. Typically, a linear hypointensity is observed on T1 W images. MRI is also highly sensitive to marrow abnormalities surrounding the fracture line, which appear as hypointensity on T1 W images and hyperintensity on fluid-sensitive sequences. Such signal changes are thought to be a combination of bone marrow edema, intraosseous haemorrhage, and/or granulation tissue and help to identify even undisplaced fractures. However, in the absence of a history of trauma and linear hypointensities on T1 W images, isolated bone marrow edema may represent other pathologies such as osteoid osteoma and sclerosing osteomyelitis.