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MR thermometry for monitoring tumor ablation

  • Magnetic Resonance
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Abstract

Local thermal therapies are increasingly used in the clinic for tissue ablation. During energy deposition, the actual tissue temperature is difficult to estimate since physiological processes may modify local heat conduction and energy absorption. Blood flow may increase during temperature increase and thus change heat conduction. In order to improve the therapeutic efficiency and the safety of the intervention, mapping of temperature and thermal dose appear to offer the best strategy to optimize such interventions and to provide therapy endpoints. MRI can be used to monitor local temperature changes during thermal therapies. On-line availability of dynamic temperature mapping allows prediction of tissue death during the intervention based on semi-empirical thermal dose calculations. Much progress has been made recently in MR thermometry research, and some applications are appearing in the clinic. In this paper, the principles of MRI temperature mapping are described with special emphasis on methods employing the temperature dependency of the water proton resonance frequency. Then, the prospects and requirements for widespread applications of MR thermometry in the clinic are evaluated.

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References

  1. Lele PP (1967) Production of deep focal lesions by focused ultrasound current status. Ultrasonics 5:105–112

    Article  PubMed  CAS  Google Scholar 

  2. Dodd GD, Soulen MC, Kane RA, Livraghi T, Lees WR, Yamashita Y, Gillams AR, Karahan OI, Rhim H (2000) Minimally invasive treatment of malignant hepatic tumors: at the threshold of a major breakthrough. Radiographics 20(1):9–27

    PubMed  Google Scholar 

  3. Marrero JA (2006) Hepatocellular carcinoma. Curr Opin Gastroenterol 22(3):248–253

    Article  PubMed  Google Scholar 

  4. Memarsadeghi M, Schmook T, Remzi M, Weber M, Potscher G, Lammer J, Kettenbach J (2006) Percutaneous radiofrequency ablation of renal tumors: midterm results in 16 patients. Eur J Radiol 59(2):183–189

    Article  PubMed  Google Scholar 

  5. Mulier S, Ni Y, Frich L, Burdio F, Denys AL, De Wispelaere JF, Dupas B, Habib N, Hoey M, Jansen MC, Lacrosse M, Leveillee R, Miao Y, Mulier P, Mutter D, Ng KK, Santambrogio R, Stippel D, Tamaki K, van Gulik TM, Marchal G, Michel L (2007) Experimental and clinical radiofrequency ablation: proposal for standardized description of coagulation size and geometry. Ann Surg Oncol

  6. Tempany CM, Stewart EA, McDannold N, Quade BJ, Jolesz FA, Hynynen K (2003) MR imaging-guided focused ultrasound surgery of uterine leiomyomas: a feasibility study. Radiology 226(3):897–905. Mar

    Article  PubMed  Google Scholar 

  7. Stewart EA, Rabinovici J, Tempany CMC, Inbar Y, Regan L, Gastout B, Hesley G, Kim HS, Hengst S, Gedroye WM (2006) Clinical outcomes of focused ultrasound surgery for the treatment of uterine fibroids. Fertil Steril 85(1):22–29

    Article  PubMed  Google Scholar 

  8. Furusawa H, Namba K, Thomsen S, Akiyama F, Bendet A, Tanaka C, Yasuda Y, Nakahara H (2006) Magnetic resonance-guided focused ultrasound surgery of breast cancer: reliability and effectiveness. J Am Coll Surg 203(1):54–63

    Article  PubMed  Google Scholar 

  9. Zippel DB, Papa MZ (2005) The use of MR imaging guided focused ultrasound in breast cancer patients; a preliminary phase one study and review. Breast Cancer 12:32–38

    Article  PubMed  Google Scholar 

  10. Uchida T, Ohkusa H, Yamashita H, Shoji S, Nagata Y, Hyodo T, Satoh T (2006) Five years experience of transrectal high-intensity focused ultrasound using the Sonablate device in the treatment of localized prostate cancer. Int J Urol 13(3):228–233

    Article  PubMed  Google Scholar 

  11. Kennedy JE, Wu F, ter Haar GR, Gleeson FV, Phillips RR, Middleton MR, Cranston D (2004) High-intensity focused ultrasound for the treatment of liver tumours. Ultrasonics 42(1–9):931–935

    Article  PubMed  CAS  Google Scholar 

  12. Hacker A, Michel MS, Marlinghaus E, Kohrmann KU, Alken P (2006) Extracorporeally induced ablation of renal tissue by high-intensity focused ultrasound. BJU Int 97(4):779–785

    Article  PubMed  Google Scholar 

  13. Wu F, Wang ZB et al (2003) Non-invasive ablation of high intensity focused ultrasound for the treatment of patients with malignant bone tumours. J Bone Joint Surg (Br) 87-B(Issue Supp I):4

    Google Scholar 

  14. Wang X, Sun J (2002) High-intensity focused ultrasound in patients with late-stage pancreatic carcinoma. Chin Med J (Engl) 115(9):1332–1335

    Google Scholar 

  15. Guilhon E, Quesson B, Moraud-Gaudry F, de Verneuil H, Canioni P, Salomir R, Voisin P, Moonen CTW (2003) Image-guided control of transgene expression based on local hyperthermia. J Molecular Imaging 2(1):11–17

    Article  CAS  Google Scholar 

  16. Madio DP, Van Gelderen P, DesPres D, Olson AW, de Zwart JA, Fawcett TW, Holbrook N, Mandel M, Moonen CTW (1998) On the feasibility of MRI-guided focused ultrasound for local induction of gene expression. J Magn Reson Imaging 8:101–104

    Article  PubMed  CAS  Google Scholar 

  17. Sapareto SA, Dewey WCL (1984) Thermal dose determination in cancer therapy. Int J Radiation Oncology Biol Phys 10:787–800

    CAS  Google Scholar 

  18. Lepetit-Coiffe M, Quesson B, Seror O, Dumont E, Le Bail B, Moonen CTW, Trillaud H (2006) Real-time monitoring of radiofrequency ablation of rabbit liver by respiratory-gated quantitative temperature MRI. J Magn Reson Imaging 24:152–159

    Article  PubMed  Google Scholar 

  19. Parker DL, Smith V, Sheldon P, Crooks LE, Fussell L (1983) Temperature distribution measurements in two-dimensional NMR imaging. Med Phys 10(3):321–325

    Article  PubMed  CAS  Google Scholar 

  20. Fried MP, Morrison PR, Hushek SG, Kernahan GA, Jolesz FA (1996) Dynamic T1-weighted magnetic resonance imaging of interstitial laser photocoagulation in the liver: observations on in vivo temperature sensitivity. Lasers Surg Med 18(4):410–419

    Article  PubMed  CAS  Google Scholar 

  21. Graham SJ, Bronskill MJ, Henkelman RM (1998) Time and temperature dependence of MR parameters during thermal coagulation of ex vivo rabbit muscle. Magn Reson Med 39(2):198–203

    Article  PubMed  CAS  Google Scholar 

  22. Le Bihan D, Delannoy J, Levin RL (1989) Temperature mapping with MR imaging of molecular diffusion: application to hyperthermia. Radiology 171(3):853–867

    PubMed  Google Scholar 

  23. De Poorter J, De Wagter C, De Deene Y, Thomsen C, Stahlberg F, Achten E (1995) Noninvasive MRI thermometry with the proton resonance frequency (PRF) method: in vivo results in human muscle. Magn Reson Med 33(1):74–81

    Article  PubMed  Google Scholar 

  24. Ishihara Y, Calderon A, Watanabe H, Okamoto K, Suzuki Y, Kuroda K et al (1995) A precise and fast temperature mapping using water proton chemical shift. Magn Reson Med 34(6):814–823

    Article  PubMed  CAS  Google Scholar 

  25. Peters RD, Henkelman RM (2000) Proton-resonance frequency shift MR thermometry is affected by changes in the electrical conductivity of tissue. Magn Reson Med 43:62–71

    Article  PubMed  CAS  Google Scholar 

  26. Wlodarczyk W, Boroschewski R, Hentschel M, Wust P, Monich G, Felix R (1998) Three-dimensional monitoring of small temperature changes for therapeutic hyperthermia using MR. J Magn Reson Imaging 8(1):165–174

    Article  PubMed  CAS  Google Scholar 

  27. Quesson B, de Zwart JA, Moonen CTW (2000) Magnetic resonance temperature imaging for guidance of thermotherapy. J Magn Reson Imaging 12(4):525–533

    Article  PubMed  CAS  Google Scholar 

  28. Denis de Senneville B, Quesson B, Moonen CTW (2005) Magnetic resonance temperature imaging. Int J Hypertherm 21(6):515–531

    Article  CAS  Google Scholar 

  29. de Zwart JA, Vimeux FC, Delalande C, Canioni P, Moonene CT (1999) Fast lipid-suppressed MR temperature mapping with echo-shifted gradient-echo imaging and spectral-spatial excitation. Magn Reson Med 42(1):53–59

    Article  PubMed  Google Scholar 

  30. McDannold N, Hynynen K, Wolf D, Wolf G, Jolesz F (1998) MRI evaluation of thermal ablation of tumors with focused ultrasound. J Magn Reson Ig 8:91–100

    Article  CAS  Google Scholar 

  31. Cline HE, Hynynen K, Hardy CJ, Watkins RD, Schenck JF, Jolesz FA (1994) MR temperature mapping of focused ultrasound surgery. Magn Reson Med 31:628–636

    Article  PubMed  CAS  Google Scholar 

  32. Popat S, Lopez J, Chan S, Waters J, Cominos M, Rutter D, Hill ME (2006) Palliative treatments for patients with inoperable gastroesophageal cancers. Int J Palliat Nurs 12(7):306–317

    PubMed  Google Scholar 

  33. Dahan L, Ries P, Laugier R, Seitz JF (2006) Palliative endoscopic treatments for esophageal cancers. Gastroenterol Clin Biol 30(2):253–261

    Article  PubMed  Google Scholar 

  34. Germain D, Chevallier P, Laurent A, Savart M, Wassef M, Saint-Jalmes H (2001) MR monitoring of laser-induced lesions of the liver in vivo in a low-field open magnet: temperature mapping and lesion size prediction. J Magn Reson Imaging 13(1):42–49

    Article  PubMed  CAS  Google Scholar 

  35. Vogl TJ, Straub R, Zangos S, Mack MG, Eichler K (2004) MR-guided laser-induced thermotherapy (LITT) of liver tumours: experimental and clinical data. Int J Hyperthermia 20(7):713–724

    Article  PubMed  Google Scholar 

  36. Vogl TJ, Fieguth HG, Eichler K, Straub R, Lehnert T, Zangos S, Mack M (2004) Laser-induced thermotherapy of lung metastases and primary lung tumors. Radiologe 44(7):693–699

    Article  PubMed  CAS  Google Scholar 

  37. Vogl TJ, Lehnert T, Wetter A, Mack MG, Wurster MG (2005) Interventional radiology in Carney triad. Eur Radiol 15(4):833–837

    Article  PubMed  Google Scholar 

  38. Fiorella ML, Ross DA, White RI, Sabba C, Fiorella R (2004) Hereditary haemorrhagic telangiectasia: state of the art. Acta Otorhinolaryngol Ital 24(6):330–336

    PubMed  CAS  Google Scholar 

  39. Maataoui A, Qian J, Mack MG, Straub R, Oppermann E, Khan MF, Knappe V, Vogl TJ (2005) Laser-induced Interstitial thermotherapy (LITT) in hepatic metastases of various sizes in an animal model. Rofo 177(3):405–410

    PubMed  CAS  Google Scholar 

  40. Eyrich GK, Bruder E, Hilfiker P, Dubno B, Quick HH, Patak MA, Gratz KW, Sailer HF (2000) Temperature mapping of magnetic resonance-guided laser interstitial thermal therapy (LITT) in lymphangiomas of the head and neck. Lasers Surg Med 26(5):467–476

    Article  PubMed  CAS  Google Scholar 

  41. Atsumi H, Matsumae M (2005) Laser interstitial thermo therapy (LITT) for brain tumors. Nippon Rinsho 63(Suppl 9):495–498

    PubMed  Google Scholar 

  42. Peters RD, Chan E, Trachtenberg J, Jothy S, Kapusta L, Kucharczyk W et al (2000) Magnetic resonance thermometry for predicting thermal damage: an application of interstitial laser coagulation in an in vivo canine prostate model. Magn Reson Med 44(6):873–883

    Article  PubMed  CAS  Google Scholar 

  43. Vigen KK, Daniel BL, Pauly JM, Butts K (2003) Triggered, navigated, multi-baseline method for proton resonance frequency temperature mapping with respiratory motion. Magn Reson Med 50(5):1003–1010

    Article  PubMed  Google Scholar 

  44. McGahan JP, Browning PD, Brock JM, Teslik H (1990) Hepatic ablation using radiofrequency electrocautery. Invest Radiol 25:267–270

    Article  PubMed  CAS  Google Scholar 

  45. Rossi S, Fornari F, Pathies C, Buscarini L (1990) Thermal lesions induced by 480 KHz localized current field in guinea pig and pig liver. Tumori 76:54–57

    PubMed  CAS  Google Scholar 

  46. Nour SG (2004) Standardization of terms and reporting criteria for imageguided tumor ablation. Radiology 232:626–627; author reply 627

    Article  PubMed  Google Scholar 

  47. Chen MH, Yang W, Yan K et al (2004) Large liver tumors: protocol for radiofrequency ablation and its clinical application in 110 patients-mathematic model, overlapping mode, and electrode placement process. Radiology 232:260–271

    Article  PubMed  Google Scholar 

  48. Solbiati L, Ierace T, Tonolini M, Cova L (2004) Guidance and monitoring of radiofrequency liver tumor ablation with contrast-enhanced ultrasound. Eur Journ Radiol 51(Suppl):S19–S23

    Article  Google Scholar 

  49. Solbiati L, Tonolini M, Cova L (2004) Monitoring RF ablation. Eur Radiol 14(Suppl 8):P34–P42

    PubMed  Google Scholar 

  50. Gellermann J, Wlodarczyk W, Feussner A, Fahling H, Nadobny J, Hildebrandt B, Felix R, Wust P (2005) Methods and potentials of magnetic resonance imaging for monitoring radiofrequency hyperthermia in a hybrid system. Int J Hyperthermia 21(6):497–513

    Article  PubMed  CAS  Google Scholar 

  51. Lepetit-Coiffe M, Quesson B, Seror O, Dumont E, Le Bail B, Moonen CTW, Trillaud H (2006) Real-time monitoring of radiofrequency ablation of rabbit liver by respiratory-gated quantitative temperature MRI. J Magn Reson Imaging 24(1):152–159

    Article  PubMed  Google Scholar 

  52. Rhim H, Goldberg SN, Dodd GD 3rd et al (2001) Essential techniques for successful radio-frequency thermal ablation of malignant hepatic tumors. Radiographics 21(spec no):S17–S35; discussion S36–S19

    PubMed  Google Scholar 

  53. Aube C, Schmidt D, Brieger J et al (2004) Magnetic resonance imaging characteristics of six radiofrequency electrodes in a phantom study. J Vasc Interv Radiol 15:385–392

    PubMed  Google Scholar 

  54. Demura K, Morikawa S, Murakami K, Sato K, Shiomi H, Naka S, Kurumi Y, Inubushi T, Tani T (2006) An easy-to-use microwave hyperthermia system combined with spatially resolved MR temperature maps: phantom and animal studies. J Surg Res 135(1):179–186

    Article  PubMed  Google Scholar 

  55. Sato K, Morikawa S, Inubushi T, Kurumi Y, Naka S, Haque HA, Demura K, Tani T (2005) Alternate biplanar MR navigation for microwave ablation of liver tumors. Magn Reson Med Sci 4(2):89–94

    Article  PubMed  Google Scholar 

  56. Lynn JG, Putman TJ (1944) Histological and cerebral lesions produced by focused ultrasound. Am J Pathol 20:637–649

    PubMed  CAS  Google Scholar 

  57. Cline HE, Schenck JF, Hynynen K, Watkins RD, Souza SP, Jolesz FA (1992) MR-guided focused ultrasound surgery. J Comput Assist Tomogr 16(6):956–965

    Article  PubMed  CAS  Google Scholar 

  58. Pernot M, Aubry JF, Tanter M, Thomas JL, Fink M (2003) High power transcranial beam steering for ultrasonic brain therapy. Phys Med Biol 48(16):2577–2589

    Article  PubMed  CAS  Google Scholar 

  59. Hynynen K, McDannold N, Clement G, Jolesz FA, Zadicario E, Killiany R, Moore T, Rosen D (2006) Pre-clinical testing of a phased array ultrasound system for MRI-guided noninvasive surgery of the brain-a primate study. Eur J Radiol 59(2):149–156

    Article  PubMed  Google Scholar 

  60. Ram Z, Cohen ZR, Harnof S, Tal S, Faibel M, Nass D, Maier SE, Hadani M, Mardor Y (2006) Magnetic resonance imaging-guided, high-intensity focused ultrasound for brain tumor therapy. Neurosurgery 59(5):949–955

    PubMed  Google Scholar 

  61. Denis de Senneville B, Mougenot C, Moonen CTW (2007) Real time adaptive methods for treatment of mobile organs by MRI controlled high intensity focused ultrasound. Magn Reson Med 57(2):319–330

    Article  Google Scholar 

  62. Bennett WR (1962) Electrical noise. McGraw Hill, New-York

    Google Scholar 

  63. Gudbjartsson H, Patz S (1995) The rician distribution of noisy MRI data. Magn Reson Med 34:910–914

    Article  PubMed  CAS  Google Scholar 

  64. Sijbers J, den Dekker AJ (2004) Maximum likelihood estimation of signal amplitude and noise variance from MR data. Magn Reson Med 51:589–594

    Article  Google Scholar 

  65. De Poorter J, De Wagter C, De Deene Y, Thomson C, Stahlberg F, Achten E (1994) The proton resonance frequency shift method compared with molecular diffusion for quantitative measurement of two dimensional time dependent temperature distribution in phantom. J Magn Reson 103:234–241

    Article  Google Scholar 

  66. Young IR, Hajnal JV, Roberts IG, Ling JX, Hill-Cottingham RJ, Oatridge A et al (1996) An evaluation of the effects of susceptibility changes on the water chemical shift method of temperature measurement in human peripheral muscle. Magn Reson Med 36(3):366–374

    Article  PubMed  CAS  Google Scholar 

  67. Mougenot C, Salomir R, Palussière J, Grenier N, Moonen CTW (2004) Automatic spatial and temporal temperature control for MR-guided focused ultrasound using fast 3D MR thermometry and multispiral trajectory of the focal point. Magn Reson Med 52:1005–1015

    Article  PubMed  Google Scholar 

  68. Kennedy JE, ter Haar GR, Cranston D (2003) High intensity focused ultrasound: surgery of the future? Br J Radiol 76(909):590–599

    Article  PubMed  CAS  Google Scholar 

  69. Scheffler K (2004) Fast frequency mapping with balanced SSFP: theory and application to proton-resonance frequency shift thermometry. Magn Reson Med 51(6):1205–1211

    Article  PubMed  Google Scholar 

  70. Riederer SJ (1996) Recent technical advances in MR imaging of the abdomen. J Magn Reson Imaging 6:822–832

    Article  PubMed  CAS  Google Scholar 

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Acknowledgements

European Union, NoE “Diagnostic Molecular Imaging”; Ligue National Contre le Cancer, Conseil Régional d’Aquitaine, Philips Medical Systems, CDTU canceropôle network.

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Correspondence to Chrit T. W. Moonen.

Appendix

Appendix

Acquisition, image processing and visualization sequence for MR temperature mapping

PRF thermometry uses a gradient echo acquisition and may benefit from the wide number of rapid gradient echo imaging techniques developed for several MRI applications [69], and widely available on state-of-the-art MRI equipment. A compromise has to be made in the choice of the acquisition parameters for a given imaging sequence and a target organ with the following objectives:

  • High temporal (1–5 s) and spatial (1–3 mm) resolution.

  • High temperature precision. For that purpose, TE must be similar to \({\text{T}}^{*}_{2} .\) In addition, the signal to noise ratio (SNR) is directly related to uncertainty in temperature estimate. For example, to obtain a temperature precision of 1°C, SNR should be at least 9 in the kidney (for which the typical value of \({\text{T}}^{*}_{2} \)∼30–40 ms is obtained at 1.5T), 23 in the liver \({\left( {{\text{T}}^{*}_{2} \sim 15\,ms} \right)}\) and 5 in the brain \({\left( {{\text{T}}^{*}_{2} \sim 60 - 70\,ms} \right)}.\) It can be noticed that rather low SNR values are sufficient to obtain accurate temperature maps (as compared to SNR requirements for visualization of anatomical structures).

  • No motion artifacts. Motion restraining devices in the positioning of the patient can be used. In addition, the simplest technique to reduce periodic motion artifacts is to synchronize the acquisition of the images to a stable part of the cycle (e.g., at the end of expiration for breathing). Synchronization can be achieved by triggering the MR pulse sequence [43] based on electric signals provided by a pressure sensor (“respiratory gating”) or cardiac electrodes (“cardiac gating”). Alternatively, MR methods can be employed using navigator echoes. The major drawback of those methods is that the temporal resolution depends on the motion frequency and a limited set of images can be acquired during a respiratory cycle (~5 s for humans).

  • Elimination of potential source of artifacts generated by the presence of lipids (since the temperature dependency of the resonance frequency of lipid hydrogen is nearly zero). In practice, lipid contribution to the MR signal can be conveniently suppressed in gradient echo imaging by frequency-selective slice excitation [29] or alternative methods (as selective fat saturation or inversion recovery).

  • Low image distortions. Magnetic susceptibility is usually spatially inhomogeneous, possibly inducing important image distortions, especially in the case of rapid phase-sensitive, PRF-based, MR thermometry.

The reconstructed signal is a complex number: grey levels on anatomical images are proportional to the magnitude value whereas its phase value relates to the proton resonance frequency. This initial data processing is done on-line by the MR acquisition computer. Then, temperature computation requires the use of reference phase maps [23, 24]. This specific processing is not available on standard MRI. Real and imaginary data are thus transferred on-line to a workstation in charge of temperature computation and visualization and, if possible, control of the heating device. Temperature maps are thus computed by analyzing contrast variation on phase images [27] (see Eq. 1).

Artifacts on temperature maps should then be reduced to a level of negligible error both with respect to anatomy as well as temperature. Artifacts in anatomy appearing in gradient echo imaging have been reviewed elsewhere [70]. Temperature mapping using the PRF method is particularly subject to thermometry errors since a small phase change may not lead to errors in anatomical features, but give significant thermometry errors via Eq. 1). On-line PRF temperature measurement may only be reliable when potential problems are eliminated due to [28]:

  • possible low SNR values due to the use of rapid acquisition sequences or lack of water hydrogen signal in the observed region,

  • spatial and temporal drift of the magnetic field,

  • local phase discontinuities and wrapping: the observable phase signal is 2π-periodic (it is a function of the wrapped phase) and accounts for the noise sources present in MR imaging. A robust unwrapping algorithm is required for accurate temperature computation as thermal map results from phase difference (see Eq. 1) [23, 24]. As temperature computation is performed individually for each voxel, aliasing problem can be solved using a temporal unwrapping correction. Temperature has to be unwrapped in order to correct for possible temporal discontinuities by bringing back Δφ in the interval [−π,π] by adding or subtracting 2π. However, phase difference can exceed 2π during the complete intervention in the case of important rise of temperature. As changes in phase variations between successive images are much smaller, temperature aliasing correction is performed on successive acquisitions.

Accurate MR temperature monitoring has been demonstrated for immobilized organ. Techniques are now being developed to allow MR temperature measurement of mobile organs. Much attention is paid to organs of the abdomen as they are prone to periodic displacements induced by breathing or cardiac activity. Accelerated acquisition techniques are used (acquisition time per image faster than typical motion period) and the phase perturbation associated with organ motion is analyzed during a pre-treatment step. A collection of multiple baseline reference phase images for different positions of the organ is used to generate temperature maps. Since this is not the primary focus of this paper, the reader is referred to recent articles [28, 43, 61].

Systematic quality control of rapid, on-line, temperature maps should then be carried out, in particular when artifacts may occur due to motion and to specific MR image reconstruction such as parallel imaging, which may induce spatially dependant SNR losses. Automatic and semi-automatic therapy controls require continuous assessment of the reliability of the available temperature maps. The temperature standard deviation is a good indicator of thermometry quality in a region where no heating is performed. Depending on the application, a typical maximal value may be defined by the radiologist (2°C for instance). During the intervention, this criterion is hard to evaluate within the targeted area because of the temperature rise. However, an evaluation can be carried out outside the heated region, thus approximating the quality in the target region. If the quality tests fail, the erroneous image should be rejected and additional computations be performed (for example, the last correctly acquired image is taken into account). If the quality tests succeed, the thermal dose map is computed using Eq. 2.

Images can thus be displayed, analyzed and stored. Visualization should be in real-time and include temperature and thermal dose maps, and allow evaluation of the entire target volume (or at least three parallel maps or two orthogonal maps).

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de Senneville, B.D., Mougenot, C., Quesson, B. et al. MR thermometry for monitoring tumor ablation. Eur Radiol 17, 2401–2410 (2007). https://doi.org/10.1007/s00330-007-0646-6

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