Several technological challenges exist to apply Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) for treatment of liver or kidney in particular challenges related to the motion of these organs. This study tests a new software to improve thermometry accuracy in mobile organs in patients with liver or kidney tumors. In the same time, the trajectory of the target in 3D is analyzed.

Liver and kidney tumors represent a major health problem because most patients are unsuitable for curative treatment with surgery. Thus, percutaneous ablation, using radio frequency (RF), is preferred : an interstitial electrode that delivers alternative current is placed into the tissue. Consequently, the development of an accurate and completely non-invasive method based on MR guided HIFU treatment is of particular interest since the energy source is located outside the body. There is no incision. For the patient, it provides a treatment option with reduced trauma and improved quality of life, and for the society, it provides reduced hospitalization time and reduced costs.

MRgHIFU has already been tested clinically in tumors of immobilized tissues as uterine leiomyoma. However, several technological challenges exist to apply it for treatment of the liver or the kidney especially challenges related to the motions of these organs. In order to improve the therapeutic efficiency and the safety of the intervention, real time mapping of temperature and thermal dose appear to offer the best strategy to optimize such interventions and provide clinical therapy endpoints. Among imaging modalities, MRI Proton Resonance Frequency based method appears to be the ideal tool for temperature mapping.

One major drawback of PRF thermometry is its high sensitivity to motion. Therefore motion correction is necessary to use PRF thermometry in mobile organs such as the liver or kidneys. To correct artefacts generated in temperature maps by periodical organ motion, a new technique was developed in the IMF lab of Bordeaux University Hospital.

The primary outcome of this study is to evaluate the precision of multiplanar MR imaging with real time motion compensation in hepatic or renal tumour patient.

Secondary outcomes are :

• Characterization of 3d movements of the tumour and test if imaging is improved when the imaging plan contains the main axis of movement.
• Ballistic: we need to identify all anatomical structures which are in the way of the HIFU beam in order to define the types of tumour suitable for future treatments
• Another outcome is to define what modifications are needed in order to treat patients such as depth of treatment, power level. We also need to see the target, ribs, and the transducer in order to evaluate the number of transducer elements to be turned off during treatment.

Inclusion Criteria:

• Liver tumors treated or not : HCC, liver metastases of colorectal cancer, hepatocellular adenoma, focal and nodular hyperplasia,
• Kidney tumors : carcinoma
• more than 18 years old

Exclusion Criteria:

• Tumours of the liver dome
• Deprived of their liberty by court
• Pregnant woman
• Contraindication to MRI examination
• Contraindication to including gadolinium salts injection