Hepatic and Renal Thermography Using Magnetic Resonance Imaging
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
Allocation: Non-Randomized, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Basic Science
Temperature standard deviation
To test the ability of this method to improve thermometry accuracy, temperature standard deviations will be studied. Indeed, temperature standard deviations reflect thermometry inaccuracy in absence of temperature variations. Temperature standard deviation in each pixel will be measured over a temporal window. Two regions of interest (ROI) determined by the operator will be considered: the first one in the tumor, the second one for the whole organ.
Duration of MRI specific sequence (15 min)
Hervé TRILLAUD, Pr
France: Afssaps - Agence française de sécurité sanitaire des produits de santé (Saint-Denis)