Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma Value
Introduction. Display contrast can be changed nonlinearly by manipulating the gamma value of the grayscale. We investigated the contrast of the hepatobiliary-phase images acquired with different flip angles (FAs) and displayed with different gamma values in Gd-EOB-DTPA-enhanced magnetic resonance im...
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| Format: | Article |
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Wiley
2019-01-01
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| Series: | Radiology Research and Practice |
| Online Access: | http://dx.doi.org/10.1155/2019/7630671 |
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| author | Yusuke Inoue Hirofumi Hata Ai Nakajima Keiji Matsunaga Yusuke Ohzeki Tetsuya Hashimoto Hiroki Haradome |
| author_facet | Yusuke Inoue Hirofumi Hata Ai Nakajima Keiji Matsunaga Yusuke Ohzeki Tetsuya Hashimoto Hiroki Haradome |
| author_sort | Yusuke Inoue |
| collection | DOAJ |
| description | Introduction. Display contrast can be changed nonlinearly by manipulating the gamma value of the grayscale. We investigated the contrast of the hepatobiliary-phase images acquired with different flip angles (FAs) and displayed with different gamma values in Gd-EOB-DTPA-enhanced magnetic resonance imaging. Material and Methods. Twenty patients with liver tumors were studied. Hepatobiliary-phase images were acquired at low (12°) and high (30°) FAs. Low-FA images were converted to simulate images displayed with different gamma values, using ImageJ software. To assess image contrast, the liver-to-muscle signal ratio (LMR), liver-to-spleen signal ratio (LSR), contrast ratio (CR), liver signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated. Results. The LMR, LSR, and CR were higher in the high-FA images than in the low-FA original images. Although the SNR was lower in the high-FA images, indicating an increase in noise, the CNR was higher. Raising the gamma value increased the LMR, LSR, and CR, notably decreased the SNR, and slightly decreased the CNR. Conclusion. Increasing the FA enhanced image contrast, supporting its usefulness for improving the delineation of focal liver lesions. Although the associated increase in noise may be problematic, raising the grayscale gamma value enhances the display contrast of low-FA images. |
| format | Article |
| id | doaj-art-439f675af75e45b989c2f6e83e65b676 |
| institution | Kabale University |
| issn | 2090-1941 2090-195X |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Wiley |
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| series | Radiology Research and Practice |
| spelling | doaj-art-439f675af75e45b989c2f6e83e65b6762025-02-03T06:13:13ZengWileyRadiology Research and Practice2090-19412090-195X2019-01-01201910.1155/2019/76306717630671Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma ValueYusuke Inoue0Hirofumi Hata1Ai Nakajima2Keiji Matsunaga3Yusuke Ohzeki4Tetsuya Hashimoto5Hiroki Haradome6Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara, Kanagawa, JapanDepartment of Radiology, Kitasato University Hospital, Sagamihara, Kanagawa, JapanDepartment of Radiology, Kitasato University Hospital, Sagamihara, Kanagawa, JapanDepartment of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara, Kanagawa, JapanDepartment of Radiology, Kitasato University Hospital, Sagamihara, Kanagawa, JapanDepartment of Radiology, Kitasato University Hospital, Sagamihara, Kanagawa, JapanDepartment of Diagnostic Radiology, Kitasato University Hospital, Sagamihara, Kanagawa, JapanIntroduction. Display contrast can be changed nonlinearly by manipulating the gamma value of the grayscale. We investigated the contrast of the hepatobiliary-phase images acquired with different flip angles (FAs) and displayed with different gamma values in Gd-EOB-DTPA-enhanced magnetic resonance imaging. Material and Methods. Twenty patients with liver tumors were studied. Hepatobiliary-phase images were acquired at low (12°) and high (30°) FAs. Low-FA images were converted to simulate images displayed with different gamma values, using ImageJ software. To assess image contrast, the liver-to-muscle signal ratio (LMR), liver-to-spleen signal ratio (LSR), contrast ratio (CR), liver signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated. Results. The LMR, LSR, and CR were higher in the high-FA images than in the low-FA original images. Although the SNR was lower in the high-FA images, indicating an increase in noise, the CNR was higher. Raising the gamma value increased the LMR, LSR, and CR, notably decreased the SNR, and slightly decreased the CNR. Conclusion. Increasing the FA enhanced image contrast, supporting its usefulness for improving the delineation of focal liver lesions. Although the associated increase in noise may be problematic, raising the grayscale gamma value enhances the display contrast of low-FA images.http://dx.doi.org/10.1155/2019/7630671 |
| spellingShingle | Yusuke Inoue Hirofumi Hata Ai Nakajima Keiji Matsunaga Yusuke Ohzeki Tetsuya Hashimoto Hiroki Haradome Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma Value Radiology Research and Practice |
| title | Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma Value |
| title_full | Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma Value |
| title_fullStr | Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma Value |
| title_full_unstemmed | Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma Value |
| title_short | Quantitative Evaluation of Display Contrast of Gd-EOB-DTPA-Enhanced Magnetic Resonance Images: Effects of the Flip Angle and Grayscale Gamma Value |
| title_sort | quantitative evaluation of display contrast of gd eob dtpa enhanced magnetic resonance images effects of the flip angle and grayscale gamma value |
| url | http://dx.doi.org/10.1155/2019/7630671 |
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