MR‐guided microwave thermocoagulation therapy of liver tumors: Initial clinical experiences using a 0.5 T open MR system

Morikawa, Shigehiro; Inubushi, Toshiro; Kurumi, Yoshimasa; Naka, Shigeyuki; Sato, Koichiro; Tani, Tohru; Yamamoto, Ikuo; Fujimura, Masaki

doi:10.1002/jmri.10198

Cited by 97 publications

(54 citation statements)

References 12 publications

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“…Each workphase is associated with each page of the wizard interface, which navigates the operator to follow the clinical workflow easily and intuitively. The workphases are defined based on the clinical workflow of MRI-guided robotic transperineal prostate biopsy and brachytherapy, but are consistent with most MRI-guided robotic intervention (e.g., liver ablation therapy [14]). …”

Section: Discussionmentioning

confidence: 99%

Software Strategy for Robotic Transperineal Prostate Therapy in Closed-Bore MRI

Tokuda

Fischer

Csoma

et al. 2008

Medical Image Computing and Computer-Assisted Intervention – MICCAI 2008

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A software strategy to provide intuitive navigation for MRI-guided robotic transperineal prostate therapy is presented. In the system, the robot control unit, the MRI scanner, and open-source navigation software are connected to one another via Ethernet to exchange commands, coordinates, and images. Six states of the system called "workphases" are defined based on the clinical scenario to synchronize behaviors of all components. The wizard-style user interface allows easy following of the clinical workflow. On top of this framework, the software provides features for intuitive needle guidance: interactive target planning; 3D image visualization with current needle position; treatment monitoring through real-time MRI. These features are supported by calibration of robot and image coordinates by the fiducial-based registration. The performance test shows that the registration error of the system was 2.6 mm in the prostate area, and it displayed real-time 2D image 1.7 s after the completion of image acquisition.

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Section: Discussionmentioning

confidence: 99%

Software Strategy for Robotic Transperineal Prostate Therapy in Closed-Bore MRI

Tokuda

Fischer

Csoma

et al. 2008

Medical Image Computing and Computer-Assisted Intervention – MICCAI 2008

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“…There are reports on the use of temperature maps derived from MR signals, such as laser hyperthermia [5,6], coagulation by radio frequency (RF) waves [7] and microwaves [8], and ablation by focused ultrasound [9,10].…”

Section: Introductionmentioning

confidence: 99%

Real‐time organ motion tracking and fast image registration system for MRI‐guided surgery

Tokuda¹,

Hirano²,

Tsukamoto³

et al. 2005

Systems & Computers in Japan

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SUMMARYThe advantage of magnetic resonance imaging (MRI)-guided surgery, in which MR images taken during surgery are used to guide the surgery, has been recognized recently. However, there is a problem, due to long imaging time of MRI, that it is difficult to capture the respiratory organ motion. It is often a constraint that the patient must hold his or her breath, especially in the treatment of the abdominal region. Consequently, this paper proposes a method of eliminating this constraint in MRI-guided surgery by real-time monitoring of the movement of the organ involved in the surgery by means of the signal derived from MRI. Specifically, the navigator echo is extracted in imaging during surgery. The movement of the organ involved in surgery is detected on the basis of the change in the calculated projection profile, and the results are presented to the surgeon. In this study, the procedure is built into a 1.5-T clinical MRI system. The feasibility of the proposed system was examined under clinical conditions by evaluating its accuracy and delay in a phantom experiment, and also in an in vivo experiment on the liver of a volunteer. The results are reported in this paper.

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“…Therefore, we have combined microwave ablation and MR image guidance using a 0.5-tesla, vertically oriented, open-conˆguration MR scanning system [9][10][11] and already performed MR-guided microwave coagulation therapy in over 200 patients with primary or metastatic liver tumors. MR temperature monitoring is useful in assessing therapeutic eŠects, but it is time consuming and di‹cult to apply to all sessions of repeated punctures and ablations during one procedure.…”

Section: Introductionmentioning

confidence: 99%

Correlation between High Field MR Images and Histopathological Findings of Rat Transplanted Cancer Immediately after Partial Microwave Coagulation

et al. 2008

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Purpose: To investigate the immediate eŠects of microwave coagulation on rat tumors in various magnetic resonance (MR) images at high magneticˆeld strength using histopathological examinations as reference.Materials and Methods: Tumors implanted in rat femurs were partially thermocoagulated by microwave. Immediately after, T 1 -and T 2 -weighted images, diŠusion-weighted images (DWIs), and contrast-enhanced T 1 weighted images (CE-T 1 WIs) were acquired with a 7-tesla MR scanner. After measurements, tumors were examined histopathologically with hematoxylin-eosin (HE) staining and histochemically for acid phosphatase activity.Results: Without contrast, boundaries of coagulated areas were unclear on MR images, including apparent diŠusion coe‹cient (ADC) maps. CE-T 1 WIs clearly showed immediate contrast enhancement of untreated areas of tumor, and the area of enhancement gradually enlarged in 5 min. Quantitative analyses were conducted by classifying tumor areas by contrast enhancement results. Signal intensities of the areas in the MR images showed no signiˆcant diŠerences, but at the periphery, ADC values were signiˆcantly higher in areas with delayed enhancement than those with immediate enhancement. Compared with histopathologicalˆndings, with microwave thermocoagulation, increased ADC value seemed to derive from collection of extracellular ‰uid in the outer zone, where acid phosphatase activity was attenuated.Conclusion: ADC values in the areas with delayed enhancement of CE-T 1 WIs were higher than those in non-aŠected areas, but MR images could not show areas of coagulation within tumors. Clear detection of the boundaries of coagulated areas required contrast enhancement, even at magneticˆeld strength of 7T.

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MR‐guided microwave thermocoagulation therapy of liver tumors: Initial clinical experiences using a 0.5 T open MR system

Cited by 97 publications

References 12 publications

Software Strategy for Robotic Transperineal Prostate Therapy in Closed-Bore MRI

Software Strategy for Robotic Transperineal Prostate Therapy in Closed-Bore MRI

Real‐time organ motion tracking and fast image registration system for MRI‐guided surgery

Correlation between High Field MR Images and Histopathological Findings of Rat Transplanted Cancer Immediately after Partial Microwave Coagulation

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