Teaching veterinary anatomy
Computed tomography (CT), and sometimes called a CAT scan, uses special x-ray equipment to obtain images from different angles around the body. Those images are then run through a com- puter to produce a cross-section of body tissue and organs.
How does CT work? CT units produce a very thin fan of x-rays which are directed through the patient and strike a row of radiation detectors. The amount of radiation going through a specific part of the patient, and therefore reaching the detector is related to the density of the body part. A CT scanner takes numerous views of each part, and reconstructs an image based on the density of different areas.
What are the indications for CT? CT is particularly useful for looking at complex bony structures such as the skull, spine or joints. It is also useful for detecting and characterizing lung diseases. Both CT and MRI are excellent for as- sessing blood flow to an organ or region.
View : Transverse image of a mouse thorax(upper) Notes: 3 week old male white mouse with IP in- jected iodine contrast agent.
View : Sagittal (lower) Notes: 3 week old male white mouse with IP in- jected iodine contrast agent.
J. vet. anat.
Functional CT Perfusion Imaging
(5) Magnetic Resonance Imaging (MRI)
What is Magnetic Resonance Imaging (MRI)? Magnetic resonance imaging (MRI) uses radiofre- quency waves and a strong magnetic field rather than x-rays to provide remarkably clear and de- tailed pictures of internal organs and tissues.
How does MRI work? When a patient is put in a strong magnet, some of the atoms become aligned with the magnetic field. If a carefully tuned radio-frequency (RF) pulse is sent into the patient, those atoms can be tipped over. As the atoms realign themselves with the magnetic field, they give off an RF pulse that can be detected by the MRI scanner. The amount of RF signal given off, and the time at which it is re- leased are characteristic for certain tissues. RF signal changes can differentiate normal from ab- normal tissues such as those affected by cancer, infection or trauma.
What are the indications for MRI ?
MRI is useful for looking at soft tissue structures which have low contrast on conventional radio- graphs (x-rays) and complex soft tissue structures. The largest indications are in imaging the brain, spinal cord, and soft tissues of the musculoskeletal system.
Vol 1 No1, (2008) 48 - 53