The possibilities of angiography in identifying distant metastases to a large extent, excluding vascularized tumors, are also limited by the size of the node 2-2 cm. The invasive nature of the study does not exclude the possibility of various complications, up to and including renal failure. All this dramatically reduces the feasibility of its use for the primary diagnosis of volumetric formations of the liver and kidneys in the presence of currently more efficient and non-invasive methods.
One of these methods is computed tomography. Its results are less dependent on the size, location and number of metastases in the organ, allowing visualization of foci less than 20 mm and even 8 mm. Very small foci in the liver allows visualization of the spiral computed tomograph. The accuracy of the findings of a computed tomographic study reaches 87.7–91%, making it possible in 14.9% of cases to detect occult metastases. However, in some cases it is difficult to carry out a differential diagnosis between a benign process and a malignant tumor, which requires a fine-needle puncture biopsy of the formation and morphological study of the material obtained.
A significant advantage of the method is the ability to test all organs with a likely metastatic lesion, including the brain, during one study. Things to a greater degree are inherent in magnetic nuclear resonance imaging.
According to the method, it even allows differential diagnosis between metastases and primary formations of the cortex and the adrenal medulla.
However, the high cost of the study and its still very relative availability do not allow the use of computed tomography, much less magnetic nuclear resonance imaging for screening patients with generalization of the process for lung cancer. However, in clarifying the diagnosis of metastases, the value of these methods is undoubted.
A more affordable method to assess the condition of the organs of the abdominal cavity and retroperitoneal space is their ultrasonic location. In addition, its indisputable advantages can be considered non-invasive research, safety for the patient and medical staff, the speed and ease of implementation, the possibility of its repetition. The tactical significance of the results of this method is underlined by the fact that in our observations in 41.7%, focal changes in the organs studied, regarded as a possible manifestation of hematogenous metastases of lung cancer, were the only argument against surgical intervention.
Our experience with the use of ultrasonoscopy to exclude hematogenous metastases in patients with lung cancer suggests that it represents the most accurate information about the state of the liver. Predominantly secondary foci in the liver in lung cancer are multiple, hypoechoic, or isoechoic. However, the detection of hyperechoic nodes can not guarantee the good quality of the process. In this case, a highly specific sign of malignancy is the presence of a completed or unfinished site around the site ”(mourning rim). Moreover, in most cases with iso-echogenic foci, only this symptom allows visualizing metastases against the background of hepatic tissue.
A significant psychological problem in determining tactics in patients with lung cancer is the detection of a single formation in the liver in the absence of secondary foci in other organs. So, along with metastases, hyperechoic nodes can correspond to cavernous hemangioma and fatty infiltration, hypoechoic – to local nodular hyperplasia. Sometimes echo-negative metastatic nodes are difficult to differentiate from liver cysts. In addition, according to the literature, the causes of false positives can be air bubbles in the biliary system, the development of perihepatic adipose tissue, the projection of the heart chambers when scanning the left lobe, changes associated with variants of the structure of the crescent ligament. Therefore, in all caseswhen, according to ultrasonoscopy, there are no characteristic signs of a benign process and the results of the study can significantly affect further medical tactics, it is advisable to perform repeated ultrasound studies and morphological verification of the process (puncture biopsy, laparoscopy, diagnostic laparotomy).