Ultrasound, or sonography, uses high-frequency sound waves to generate images of the inside of the body. A probe called a transducer sends out sound waves that are echoed back. A computer generates images from these reflected sound waves and displays them in real time. Doppler ultrasound is a special technique that can evaluate vessels and blood flow in vessels in a unique way. Ultrasound exams do not use ionizing radiation (as used in X-rays) and there are virtually no known adverse effects. Ultrasound is inexpensive, simple and noninvasive. However, the quality of the exam may be highly dependent upon the sonographer performing the exam, the equipment used, the type of tumor or lesion being evaluated, and body build of the patient. As a result, ultrasound may not detect all tumors or characterize them accurately.
CT scanning—sometimes called CAT scanning—is a noninvasive medical test that helps physicians diagnose and treat medical conditions. CT imaging combines special X-ray equipment with sophisticated computers to produce multiple images or pictures of the inside of the body. These cross-sectional images of the area being studied can then be examined on a computer monitor. CT scans of internal organs, bone, soft tissue and blood vessels provide much greater clarity and reveal more details than regular X-ray exams. A CT scan of the liver usually involves injection of a special iodine-based dye through an IV. This dye may not be safely given in some patients with kidney disease. Also some patients may be allergic to the iodine in the dye. If you have a history of allergic reaction from a previous dye injection, you should check with your doctor prior to the exam.
Magnetic resonance imaging (MRI) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. The images can then be examined on a computer monitor and printed or copied to CD. MRI does not use ionizing radiation (X-rays). Detailed MRI images allow physicians to better evaluate parts of the body and certain diseases that may not be assessed adequately with other imaging methods such as X-ray, ultrasound or computed tomography (also called CT or CAT scanning).
The MRI examination poses almost no risk to the average patient when appropriate safety guidelines are followed. Although the strong magnetic field is not harmful in itself, medical devices that contain metal may malfunction or cause problems during an MRI exam. There is a very slight risk of an allergic reaction if contrast material is injected. Such reactions usually are mild and easily controlled by medication.
Magnetic Resonance Cholangio-Pancreatography (MRCP) is a non-invasive technique for viewing the bile ducts, the pancreatic duct, and the gallbladder using a magnetic resonance imaging (MRI) to produce detailed pictures. Unlike its more invasive counterpart, ERCP, where a fiberoptic scope is directly inserted into the patient’s stomach and small bowel, MRCP is entirely non-invasive. However, it is limited to diagnosis only and no therapeutic maneuvers can be performed.
MRCP is an outpatient procedure that involves lying very still in an MRI scanner for several minutes at a time. The entire experience should be over in less than 20 minutes. Having MRCP does not expose you to radiation. However, because MRCP uses a strong magnetic field, people with some types of metal objects in their bodies cannot have this test.