The detection of liver metastases at the early stages is the only choice to improve the health of patients significantly. This can be accomplished by chemotherapy and surgical procedures. Chemotherapy may enhance the unique regenerative capacity of the liver parenchyma in the liver metastases condition. Whereas, the preeminent effect for liver surgery is accomplished when the volume of lesions are few in number and particularly when the lesions are localized to a single lobe. All these factors point towards early detection as a useful contributor to the improved long-term outcome. New types of palliative and possibly curative treatments for liver metastases, such as thermal and radio-frequency ablation also require early and precise recognition of cancers. The accuracy of information for staging, stratification for treatment and prognosis is all improved by the early detection of liver disease.
How Is Liver Metastases Diagnosed?
- Hemoglobin level.
- Liver function test: ALP elevated, bilirubin elevated, albumin decrease/
- Ultrasound scan.
- CT scan and MRI.
- Biopsy under ultrasound control.
Blood Test – Blood tests can disclose the liver function abnormalities. Low levels of red blood cells, hemoglobin and liver enzymes help to identify the problems. Liver function tests are blood tests that show liver enzyme levels whether higher or lower. These enzymes are referred to as serum biomarkers that are linked to cancer primary liver cancer and liver metastasis. When primary liver cancer or liver metastasis is present, there may be higher levels of alpha-fetoprotein detected in the blood.
CT Scan, MRI, and Ultrasound – A computed tomography (CT) scan and magnetic resonance imaging (MRI) has greater application in identifying the liver metastases. Large liver metastases are greater than about 1 to 2 cm in size can be effortlessly measurable by CT or MRI techniques which have a high level of accuracy. However, microscopic metastases i.e. smaller than 1 to 2 mm in size are very rare cannot be measured by these anatomic imaging methods. Ultrasound or sonography transmits high-frequency sound waves and echoes inside the body which helps in analysis of changes occurred in the liver. Presently, experts have focused on the early and precise diagnosis of lesions in the size range from 2 mm to 2 cm. In this size range, superparamagnetic iron oxide (SPIO) enhanced MRI is probably superior (60% sensitivity) to dual phase CT (45% sensitivity) when compared with surgery and intraoperative ultrasound.
Angiogram – Angiogram produces high-contrast images of internal structures help to measure microscopic lesions. Selective hepatic angiography may demonstrate hypervascular liver metastases by showing capillary blush in involved areas, highlighting the potential response of tumors to embolization. Angiography is essential when hepatic vascular intervention is planned.
Biopsy – Removing a biospecimen from liver may cause the risk of bleeding, bruising and infection. However, doctor advice is recommended for tissue analysis, which helps to detect cancer accurately.
All metastases including liver begin with the micro size of tumor cells. When they reach a size of 100–200 microns, humoral factors stimulate the growth of new and abnormal blood vessels around the periphery of the lesion. At this size, the lesions are not visible on conventional imaging, but might possibly be detected by dynamic radionuclide or ultrasound techniques as a result of the disturbance in hepatic arterial/portal flow ratios which is caused by the tumor angiogenesis.
Conclusion
Blood test, CT scan, MRI, ultrasound, angiogram, and tissue biopsy help in early recognition of liver metastasis. Metastases size ranging from 1 to 2 cm can be measured by CT and SPIO enhanced MRI. CT and MRI methods are currently only moderately successful in detecting lesions in the 2 to 15 mm size range. However, detecting lesions smaller than 2 mm is rarely possible with imaging, but might be achievable using radionuclide or doppler based perfusion techniques.
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