Body imaging in the liver of (1) Principle: The liver is composed of polygonal cells and astrocytes of the substantive organs, blood supply is very rich, after intravenous injection of radioactive colloid, a flow through the liver that is more than 90% of colloidal been hepatic stellate cell uptake, and the remaining for other reticuloendothelial system uptake. Some of the radioactive nuclide labeled compounds, the substance of the liver cells can be (polygonal cell) uptake and short stay, or when the radionuclide labeled compounds in the liver uptake, they can use the scanner or camera to detect and display. When liver disease occurs after diffuse or localized, reticular endothelial cells and liver cells are damaged, the lesion of cell uptake of radionuclides functional changes, abnormal distribution of radiation density, showing reduction or loss of, scanning the map shows the radioactive sparse or defect to determine the liver lesions of the location, size, number and morphology.
(2) imaging agent: imaging agent commonly used in colloidal 99mTc (99m casting) – sodium phytate, 99mTc-sulfur colloid, 113mIn (113m indium) colloid. Hepatobiliary imaging agent commonly used 99mTc IDA (Asia ammonia diacetate) and its derivatives, 99mTc-PMT (adjacent pyridoxal acid -5– methyl-tryptophan), 99mTc-by for Feining.
Physical description of liver imaging (3) imaging methods: gel imaging into planar imaging and SPECT, planar imaging is a multi-position method, such as the anterior, posterior and right place. Tomography or single photon emission computed tomography, check the probe along a single patient's body (liver area) one revolution, were collected 60_64 frame, three-dimensional image reconstruction using computer processing as the transverse, coronal, three point-like surface CT images. Hepatobiliary imaging using continuous shooting, immediately after intravenous injection of radioactive substances began imaging, 5,10,15 and 30 minutes after the shooting one frame, no radioactive substances into the gut if required to delay shooting time of 1 hour, 3 hours, 5 hours, 7 hours, up to 24 hours.
(4) image analysis: normal liver scans before and after the bit in the most common triangle, curved upper edge of the right lobe in the right breast under the cross; left lobe of the heart on the edge of a pressure trace, under the right costal margin and phase margin parallel. Close-sector has a limited midline depression, notch for the portal, right lobe of the right edge of the right arc prominent, the lower edge of the left lobe of the liver can be located under the xiphoid 1_4cm. In the right place, the liver was "comma-shaped." Curved upper edge and protruding front, walking down the lower edge of the line, more straight, but the lower edge of the right costal margin of not less than the lowest point. The right bit of the image receptor bit larger. After the main show in the anterior right lobe. Occlusion due to left lobe of the spine and soft tissue absorption and distance between the probe is not affected by factors such as development or development is not ideal. Right lobe of the outer edge of the slightly protruding. Liver at the lower edge of the right kidney pressure trace, developing lighter. The posterior wall of the spleen in the body, developing more anteroposterior clear.
If the liver lesions, whether benign or malignant tumor, there could be limitations of radioactive defects, and diffuse liver diseases, such as fatty liver, cirrhosis, liver amyloidosis, Primary hepatic diffuse cancer, and so will be showing a diffuse liver was sparse or patchy sparse universal.
The SPECT images of the liver is more complex, cross-sectional CT image is divided into the point-like surface and coronal plane. According to the normal anatomy of the liver can show various levels of image features. When the liver space occupying lesions, the typical surface radiation defects.
Physical description of liver imaging (5) Clinical significance: the diagnosis of liver imaging liver lesions relatively simple screening methods, diagnostic accuracy was 80% _90%, while SPECT for the detection rate of lesions than planar imaging in 10% _15% higher. Liver imaging for early cancer, lesions too small parts too deep, less than 2cm in diameter in patients with positive detection rate for liver cancer. For bulky liver cancer detection rate is relatively higher. Benign lesions of the liver, the liver imaging for the local radiation defects, not specific, only targeting no qualitative value. Therefore, clinical diagnosis, in order to accurate diagnosis requires further examination, such as B-, CT, MRI and determination of alpha-fetoprotein, etc., a comprehensive analysis.
- physical description of the liver