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

• MURAKAMI Koichiro

  Department of Surgery, Shiga University of Medical Science

• MORIKAWA Shigehiro

  Biomedical MR Science Center, Shiga University of Medical Science

• NAKA Shigeyuki

  Department of Surgery, Shiga University of Medical Science

• DEMURA Koichi

  Department of Surgery, Shiga University of Medical Science

• SATO Koichiro

  Department of Surgery, Shiga University of Medical Science

• SHIOMI Hisanori

  Department of Surgery, Shiga University of Medical Science

• KURUMI Yoshimasa

  Department of Surgery, Shiga University of Medical Science

• INUBUSHI Toshiro

  Biomedical MR Science Center, Shiga University of Medical Science

• TANI Tohru

  Department of Surgery, Shiga University of Medical Science

Abstract

Purpose: To investigate the immediate effects of microwave coagulation on rat tumors in various magnetic resonance (MR) images at high magnetic field strength using histopathological examinations as reference.<br> Materials and Methods: Tumors implanted in rat femurs were partially thermocoagulated by microwave. Immediately after, T₁- and T₂-weighted images, diffusion-weighted images (DWIs), and contrast-enhanced T₁ weighted images (CE-T₁WIs) 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.<br> Results: Without contrast, boundaries of coagulated areas were unclear on MR images, including apparent diffusion coefficient (ADC) maps. CE-T₁WIs 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 significant differences, but at the periphery, ADC values were significantly higher in areas with delayed enhancement than those with immediate enhancement. Compared with histopathological findings, with microwave thermocoagulation, increased ADC value seemed to derive from collection of extracellular fluid in the outer zone, where acid phosphatase activity was attenuated.<br> Conclusion: ADC values in the areas with delayed enhancement of CE-T₁WIs were higher than those in non-affected 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 magnetic field strength of 7T.<br>

Journal

• Magnetic Resonance in Medical Sciences

  Magnetic Resonance in Medical Sciences 7 (3), 105-112, 2008

  Japanese Society for Magnetic Resonance in Medicine

Keywords

• cancer
• coagulation therapy
• diffusion-weighted imaging
• magnetic resonance imaging
• microwave

Details

• CRID: 1390001205196677632
• NII Article ID: 10024835746
• NII Book ID: AA11648770
• DOI: 10.2463/mrms.7.105
• ISSN: 18802206
• ISSN: 13473182
• Web Site: https://www.jstage.jst.go.jp/article/mrms/7/3/7_3_105/_pdf
• Web Site: https://search.jamas.or.jp/link/ui/2009105707
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed