The Research Of MRI Thermometry And MRI Image Processing

Since the twenty-first century,cardiovascular and cerebrovascular diseases,cancer and hypertension have become the top three killers of human health.Among them,cancer bothers us most,because it is very difficult to diagnose at the beginning,and easy to transfer to other organs and tissues.Traditional tumor therapies like chemotherapy and radiotherapy can bring a lot of side effects and harm to patients.In recent years,thermal therapy has become a research focus against tumor,at the same time,this new kind therapy has been adopted in clinical trials.With the help of imaging technology,thermal therapy can cause the tumor parts coagulation and degeneration with higher temperature,thus thermal therapy can reach the goal of healing the tumor.In the procedure of thermal therapy,we must inspect the temperature accurately and in real time,the supervision of temperature is the key technology.MRI thermometry has many advantages like no radiation,high space-time resolution,no trauma.With these superiorities,research towards MRI thermometry possesses unparalleled clinical significance and scientific value.This study applied MRI technology to test phantom's temperature under different circumstances,thus to investigate the influences of different parameters and methods on the accuracy of MRI temperature measurement.With the hope that this study can provide some technical guidance and references.The content in this paper can be divided into two parts:The first part is about the investigation of temperature measurement based on T1 weighted image under low field strength.Experiment results show that when TR=400ms(TE=18ms)of SE sequence,the theoretical temperature of this method is closer to the actual temperature,than TR=800ms and 1200 ms.The mean error is ±0.5?,and the root mean square error is 0.6?.Then we adopt this method of the premium parameter to test uneven heated tissue of pork liver.Results show that for uneven heated tissue,the mean error is ±2?,and the root mean square error is 2.3?.Results show that parameter TR has a great influence on temperature measurement accuracy and the temperature measurement based on this premium sequence can meet the demand of clinical mild thermotherapy in precision.The second part we adopt the PRF method to test phantom temperature.This method is nowadays the focus of international scientific research.It demands higher magnetic field intensity and stability.In this study,we compared the traditional method and improved method.Experiments show that for traditional method,the mean error is ±2.2?,and the root mean square error is 2.2?.For improved method,the mean error is ±1.1?,and the root mean square error is also 1.1?.It can meet the demand of clinical mild thermotherapy.Research results have shown the thermometry with the premium SE sequence under low field strength and with the improved method under high field strength can meet the accuracy demand of clinical mild thermotherapy.The research based on these two methods has a lot of clinical application prospect and scientific value.