Imaging studies (imaging) plays a pivotal role in
the diagnosis of liver cancer. A
good study can provide information such as tumor size, tumor number, and
whether the tumor has involved major blood vessels locally or spread outside
the liver. There are several types of studies, each has advantages and
disadvantages. In practice, several studies combined often complement each
other. On the other hand, an X-ray usually is not very helpful, and therefore,
not routinely done in improving the diagnosis
of liver cancer. Furthermore, there is no practical role for nuclear
medical scans of the liver and spleen in the execution of liver cancer. Scan
range is not very sensitive and they do not provide any additional information
beyond that provided by the scan-scan (ultrasound, CT, and MRI) others.
The ultrasound usually is the first study ordered if HCC is suspected in a patient. Accuracy of an ultrasound is very much dependent on the technician and radiologist who did the study (depending on operator). Studies from Japan and Taiwan report that ultrasound is the imaging study (imaging) are most sensitive to diagnose and mark (characterize) liver cancer. But you should know that in these studies, individuals who are very experienced doing the scans and spent up to an hour to scan every patient suspected of having liver cancer. An ultrasound has the advantages to not require contrast material intravenadan does not involve radiation. Moreover, the cost of an ultrasound is very low compared to other types of scans.
Computerized axial tomography (CT scan) is a study of the most commonly used in America to work on the liver tumors. CT study of the ideal is a spiral CT scan of the multi-phase materials using oral and intravenous contrast. The pictures taken on in three phases:
• Without intravenous contrast
•
With intravenous contrast (increase imaging) that highlights the arterial
system (arterial phase)
•
When the contrast in the venous phase
The
pictures are taken at intervals of very frequent (thin slices) when the body is
moved through the CT scanner. Many experts-radiologists use a specific protocol
that determines how the contrast in-infusion in relation to how the pictures
taken. Therefore, CT is much less operator dependent than ultrasound. However,
CT is much more expensive. Furthermore, CT requires the use of contrast
material, which has berpontensial risks of an allergic reaction and effects on
renal function less well.
There are several variations on CT scanning. For example, on a CT angiogram, which is a very invasive study (go to a body part), at-infusion intravenous contrast selectively through the hepatic artery (artery to the liver). The aim is to highlight the vessels for better vision than those with CT scan. Also, in Japan, an oily contrast material called lipiodol, which is selectively taken by liver cancer cells, has been used with CT. The purpose of this approach is to improve the sensitivity of the scan. That said, the goal is to increase the percentage of abnormal CT scans in patients who have liver cancer.
Magnetic resonance imaging (MRI) can provide the pictures are very clear from the body. Its advantages over CT is that MRI can provide views of the section per section of the body in different fields. The technology has evolved to a point where the more recent MRI can actually reconstruct images of the biliary tree (bile ducts and gallbladder) and from the arteries and veins of the liver. (The tree transports bile from the liver into bile duodemum or duodenum, the first part of the intestine). MRI studies can be made even more sensitive by using intravenous contrast material (eg, gadolinium).
MRI scans are very expensive and there is tremendous variability in the quality of the images. Quality / quality depending on the age of the machine and the patient's ability to hold breath for up to 15 to 20 seconds at a time. Furthermore, many patients, because of claustrophobia, can not tolerate being in the MRI scanner. However, now an open MRI scanners generally do not provide images of high quality images from scanners that are closed.
Advances in ultrasound technology, CT, and MRI has virtually eliminated the need for angiography. An angiography procedure involves the inclusion of a catheter into the femoral artery (in the groin) through the aorta, and kedaalam hepatic arteries, the arteries that supply (supply) of blood to the liver. Then injected contrast material, and the images of X-ray of the provision (supply) of blood through the arteries to the liver is taken. An angiogram of liver cancer showed a characteristic reddish generated by abnormal small arteries that feed the newly-formed that the tumor (neovascularization).
What then is the best imaging study for diagnosis of liver cancer? There are no easy answers. Many factors need to be put into consideration. For example, if the diagnosis of liver cancer known or scans being done for screening? What skills of doctors in patient areas? What qualities of the different scanners at a particular facility? Are there economic considerations? Does the patient have other conditions that need to be considered, such as claustrophobia or kidney disorders? Does the patient have any tools, for example, a pacemaker or a prosthetic metal tools? (Goods of metal will not allow to do an MRI).
If you live in Japan or Taiwan and have access to a radiologist (radiologist) or a liver specialist (hepatologist) with expertise in ultrasound, then it probably is as good as a CT scan. Ultrasound is also the most practical (easier and cheaper) for regular screening (surveillance). In North America, a spiral CT scan is a multi-phase scan is probably the most accurate type. However, for patients with impaired renal function or who have access to a state-of-the-art MRI scanners, MRI is probably the choice of diagnostic scans. Finally, remember that the technology of ultrasound, CT, and MRI is ever evolving with the development of these machines are better and the use of special contrast materials to further characterize (mark) tumors.
