A molecule is a structure formed of atoms of various elements. It is the smallest concentration of same or different atoms that all chemical characteristics retain.

See also Free Radicals, Osmole, Enzyme Linked lmmuno Sorbent Assay, Gas Chromatography and Gel Chromatography.

Multi-head contrast media injectors offer flexible contrast media management, simplified workflows and increased patient safety.
Contrast delivery is much more controlled and efficient when using a dual-head CT power injector. These medical devices are needed to enable the short imaging times typical of multidetector computed tomography (CT) scanners.
Triple-head injectors allow selection of a second contrast agent when two different contrast agents are used, or switching to full contrast agent containers when two identical contrast agents are used.

See also Contrast Media Injector, Syringeless CT Power Injector, Single-Head Contrast Media Injector, CT Power Injector.

A multiphase bone scintigraphy (bone scan) is a nuclear medical examination including blood flow images, immediate images, and delayed images.
The blood flow study is a dynamic sequence of planar images of the bone region of interest obtained during the injection of the radiopharmaceutical (radioactive tracer).
The immediate phase (blood pool or soft tissue study) include one or more static images of selected regions, obtained immediately after the blood flow phase within 10 min.
Delayed images (usually whole body) are usually acquired 2-5 hours after injection. Later (6-24 hour) delayed images result in a higher target to background ratio and may permit better evaluation of the pelvis if this was obscured by bladder activity on the routine images. This late imaging may be particularly helpful in patients with renal insufficiency or peripheral circulatory disorders and those with urinary retention.

Multiplanar reconstruction or reformatting is a post-processing technique to create new images from a stack of images in planes other than that of the original stack.
The use of thin slices increases the spatial resolution in the scan axis direction, allowing a high spatial resolution in all planes. Isotropic resolution results in high quality multiplanar and 3D reconstructions which are of particular benefit in CT angiography and virtual colonoscopy studies.

A myelography is a radiographic imaging procedure to visualize the spinal canal, the spinal cord, cerebrospinal fluid (CSF), intervertebral disks and nerve roots. A special contrast agent (dye) is injected through a needle into the subarachnoid space of the spinal canal. A myelogram provides a very detailed picture of the spinal cord and spinal column. A fluoroscopy displays the bones and the fluid-filled space of the spine also in motion. An additional computerized tomography (CT or CAT) scan helps to differentiate the spinal conditions better. The indications include disc herniation, spinal stenosis, tumor, and vertebral fracture.

See also Myeloscintigraphy, Fluoroscopic System, Hounsfield Unit, Bone Densitometry, Nonionic Contrast Agents.