Out of phase component of the signal from a quadrature detector.

Imaging coils are radio frequency coils used in magnetic resonance imaging for sending and/or receiving electromagnetic radiation. Several MR imaging coils in different shapes and sizes are necessary for different body parts and to handle individual applications.
For Example:
Birdcage coils provide high homogeneity and good signal to noise ratio (SNR) in brain MRI scans.
Surface coils with small coil diameter and higher SNR enable to image the temporomandibular joints (TMJ).
The implemented body coil allows the scanning of body parts with large field of views.
Micro coils are available to image finger joints.
High performance phased array coils are today state-of-the-art for a wide range of applications from head, spine, knee or shoulder to cardiac MRI.
For different types of coils see Volume Coil, Sense Coil, Array Coil, Surface Coil, and Bird Cage Coil.

See also the related poll result: '3rd party coils are better than the original manufacturer coils'

Knee and shoulder MRI exams are the most commonly requested musculoskeletal MRI scans. Other MR imaging of the extremities includes hips, ankles, elbows, and wrists. Orthopedic imaging requires very high spatial resolution for reliable small structure definition and therefore places extremely high demands on SNR.
Exact presentation of joint pathology expects robust and reliable fat suppression, often under difficult conditions like off-center FOV, imaging at the edge of the field homogeneity or in regions with complex magnetic susceptibility.
MR examinations can evaluate meniscal dislocations, muscle fiber tears, tendon disruptions, tendinitis, and diagnose bone tumors and soft tissue masses. MR can also demonstrate acute fractures that are radiographically impossible to see. Evaluation of articular cartilage for traumatic injury or assessment of degenerative disease represents an imaging challenge, which can be overcome by high field MRI applications. Currently, fat-suppressed 3D spoiled gradient echo sequences and density weighted fast spin echo sequences are the gold-standard techniques used to assess articular cartilage.
Open MRI procedures allow the kinematic imaging of joints, which provides added value to any musculoskeletal MRI practice. This technique demonstrates the actual functional impingements or positional subluxations of joints. In knee MRI examinations, the kinematical patellar study can show patellofemoral joint abnormalities.

See also Open MRI, Knee MRI, Low Field MRI.

An imaging sequence is in magnetic resonance imaging a predefined set of radio frequency - and gradient pulses to excite the hydrogen nuclei of the object being imaged.

Founded in 1991, ImaRx Pharmaceutical Corp. designs, develops and markets pharmaceuticals for medical imaging (MRI, ultrasound and computed tomography) for the radiological imaging industry.
ImaRx Pharmaceutical Corp., announced 1999 that it has been acquired by E.I DuPont de Nemours and Co., Inc.. The terms of the acquisition provide a royalty-free licensing arrangement with a newly-formed company, ImaRx LLC ("LLC"), to pursue and develop new products and technologies for drug and gene delivery independent from DuPont. Yamanouchi Pharmaceutical Co. Ltd., ImaRx' licensee for Asian territories for this product, will continue to develop the product in Asia as DuPont's licensee. ImaRx LLC will have ownership of all other targeted and therapeutic products previously owned by ImaRx, including imaging products outside of diagnostic ultrasound imaging and two other imaging products, SonoRx® and LumenHance®, which are both FDA approved and licensed to BRACCO Diagnostics.

MRI Contrast Agents: