| Background and PurposeThe liver is one of the most common sites of metastasis, and the treatment effect directly affect the patient’s quality of life and survival, so there is still some kind of big problem in malignant tumor treatment. The prognosis of metastatic liver cancer depends on the position of the primary tumor、 the stage of liver cancer、 the general condition of patients,so the1-year survival rate remains lower than50%. So,it is currently the medical challenge to select the appropriate treatment for patients, in order to prolong the lifetime.With the development of medicine,besides the surgical treatment, noninvasive procedures has been widely used because of its favorable treatment results,including radiofrequency ablation, transcatheter arterial chemoembolization, immunotherapy, and so on. At the same time,there is also a difficult problem.The assessment of postoperative effect is the key point to find out incomplete lesions and take the further treatment.Therefore,these noninvasive treatments are highly depend on the imaging technology to evaluate the results. In recent years, several studies have been taken to discuss the advantages and disadvantages of different kinds of imaging examination,such as contrast-enhanced ultrasound (CEUS), computed tomography (CT) and magnetic resonance imaging (MRJ). Among them, MRI has the characteristics of high costs and slower scanning speed. CT scans are not favorable because of its serious radiation. CEUS examinations are sometimes dependent on the operators’experience. So,in order to detect the residual or recurrent lesions timely,we need to take various imaging methods after RFA.Rapidly development of magnetic resonance imaging (DWI) in abdominal disease diagnosis make great contribution to solve the above problems. DWI is some kind of imaging technology which is sensitive to the water molecular diffusion movement.Combined with the conventional T2scan spin echo sequences and symmetrical diffusion pulses (b value), the movement of water molecules in the relevant direction become more active.The greater,the lower signal.We can calculate the apparent diffusion coefficient (ADC) of various kinds of organizations through the b values. The different ADC values are relevant with pathological changes. At present,DWI is widely used in the brain diseases,especially for the diagnosis of acute cerebral infarction, but still be in the stage of exploration in the abdomen organs application.In recent years,much more research have been taken in the liver DWI imagings,such as postoperative effect evaluation in TACE or RFA. To our knowledge,there is rare research about the residual tumors after RFA for metastatic hepatocellular carcinoma. Our study aims to explore the possibility of find out the residual nodules through the changes of ADC values.Methods:Patients with metastatic liver cancer who are tend to take RFA therapy are chosen in our study.They all take MRI scans and examinations before RFA (<1month) and7days,1month and3months after RFA procedure. The ADC values can be calculated through the matching software.Two experienced radiologists calculated the ADC values after three times (including normal liver tissue and complete ablation area and suspicious residual areas),and take the average count in consensus.As the same,two experienced ultrasound doctors analyze the ultrasound imagings, and find out residual or recurrence tumors in agreement The data are showed as mean±D. The statistical difference are compared by using a one-way analysis(ANOVA) with Tukey test and Wilcoxon rank sum test, P<0.05is considered as statistical significance.Results:Preoperative and postoperative RFA, the changes of the ADC values of normal liver tissue had no statistical significance (P>0.05). After RFA, the ADC values of center areas that were completely melting changed, and the changes were all have significant difference (P<0.05).The preoperative and postoperative ADC values differences between suspected residual tumor area had no statistical significance (P>0.05). The ADC value of completely melting area were statistical higher than the residual lesions.Residual nodules were confirmed by contrast-enhanced MRI(CEMRI)scans and CEUS.Conclusions:We studied the DWI images of metastatic hepatocellular carcinoma lesions after RFA. Through the change of the ADC values, we can be found out the residual nodules and provide the reliable diagnosis for further treatment at early time.What’s more,this is helpful to improve complete ablation rate and prolong survival for patients. |
PDF Full Text Request