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Current status of optical imaging for evaluating lymph nodes and lymphatic system.

Lee ES, Kim TS, Kim SK - Korean J Radiol (2015)

Bottom Line: Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage.Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system.This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Research Institute and Hospital, National Cancer Center, Goyang 410-769, Korea.

ABSTRACT
Optical imaging techniques use visual and near infrared rays. Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage. Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system. This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications. Emerging new optical imaging techniques and their potential are also described.

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Related in: MedlinePlus

Infrared fluorescence of indocyanine green (ICG) is more intense in dilute condition with weaker green color than in concentrated condition.A. Commercial ICG green kit. B. Photos of 0.25% ICG aqueous solution (right vial) and 0.002% ICG aqueous solution (left vial). 0.25% ICG solution is dark green in color, while 0.002% ICG aqueous solution is faint green. Near infrared (NIR) fluorescence images were obtained using fluorescence imager. C. NIR image with excitation light on. 0.002% ICG aqueous solution (left vial) shows intense fluorescence with minimal background.
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Figure 1: Infrared fluorescence of indocyanine green (ICG) is more intense in dilute condition with weaker green color than in concentrated condition.A. Commercial ICG green kit. B. Photos of 0.25% ICG aqueous solution (right vial) and 0.002% ICG aqueous solution (left vial). 0.25% ICG solution is dark green in color, while 0.002% ICG aqueous solution is faint green. Near infrared (NIR) fluorescence images were obtained using fluorescence imager. C. NIR image with excitation light on. 0.002% ICG aqueous solution (left vial) shows intense fluorescence with minimal background.

Mentions: Indocyanine green is the most commonly used NIR fluorescent contrast medium for lymphatic imaging in clinical practice. ICG was introduced to measure cardiac output and was granted FDA approval in 1959 (13). During its more than 50 years of use in various clinical settings, adverse reactions to ICG have been rarely reported (14). In general, ICG is regarded as safe; however, caution should be exercised in case of patients with renal insufficiencies (15). Although ICG appears dark green under natural light, it appears more fluorescent than green once injected into the human body in amounts < 20 mg (Fig. 1) (16). Its absorption peak is approximately 780 nm and its emission peak is approximately 830 nm in a dilute aqueous solution. Although ICG has large overlapping absorption and emission spectra, it can still be easily detected by NIR fluorescence imaging systems. Motomura et al. (17) first reported the potential of ICG as a tracer for sentinel node mapping. However, this technique is merely a substitution for blue dye without a fluorescent detecting system. In the aforementioned article, the success rate for detecting sentinel nodes guided by ICG was 74% of 172 breast cancer patients. Kitai et al. (18) reported a new sentinel lymph node mapping technique guided by ICG fluorescence using a hand-held fluorescence detection device in breast cancer patients with a detection rate of 94%. This was the first reported use of ICG as a NIR dye. Detailed clinical uses will be reviewed in the following section.


Current status of optical imaging for evaluating lymph nodes and lymphatic system.

Lee ES, Kim TS, Kim SK - Korean J Radiol (2015)

Infrared fluorescence of indocyanine green (ICG) is more intense in dilute condition with weaker green color than in concentrated condition.A. Commercial ICG green kit. B. Photos of 0.25% ICG aqueous solution (right vial) and 0.002% ICG aqueous solution (left vial). 0.25% ICG solution is dark green in color, while 0.002% ICG aqueous solution is faint green. Near infrared (NIR) fluorescence images were obtained using fluorescence imager. C. NIR image with excitation light on. 0.002% ICG aqueous solution (left vial) shows intense fluorescence with minimal background.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296273&req=5

Figure 1: Infrared fluorescence of indocyanine green (ICG) is more intense in dilute condition with weaker green color than in concentrated condition.A. Commercial ICG green kit. B. Photos of 0.25% ICG aqueous solution (right vial) and 0.002% ICG aqueous solution (left vial). 0.25% ICG solution is dark green in color, while 0.002% ICG aqueous solution is faint green. Near infrared (NIR) fluorescence images were obtained using fluorescence imager. C. NIR image with excitation light on. 0.002% ICG aqueous solution (left vial) shows intense fluorescence with minimal background.
Mentions: Indocyanine green is the most commonly used NIR fluorescent contrast medium for lymphatic imaging in clinical practice. ICG was introduced to measure cardiac output and was granted FDA approval in 1959 (13). During its more than 50 years of use in various clinical settings, adverse reactions to ICG have been rarely reported (14). In general, ICG is regarded as safe; however, caution should be exercised in case of patients with renal insufficiencies (15). Although ICG appears dark green under natural light, it appears more fluorescent than green once injected into the human body in amounts < 20 mg (Fig. 1) (16). Its absorption peak is approximately 780 nm and its emission peak is approximately 830 nm in a dilute aqueous solution. Although ICG has large overlapping absorption and emission spectra, it can still be easily detected by NIR fluorescence imaging systems. Motomura et al. (17) first reported the potential of ICG as a tracer for sentinel node mapping. However, this technique is merely a substitution for blue dye without a fluorescent detecting system. In the aforementioned article, the success rate for detecting sentinel nodes guided by ICG was 74% of 172 breast cancer patients. Kitai et al. (18) reported a new sentinel lymph node mapping technique guided by ICG fluorescence using a hand-held fluorescence detection device in breast cancer patients with a detection rate of 94%. This was the first reported use of ICG as a NIR dye. Detailed clinical uses will be reviewed in the following section.

Bottom Line: Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage.Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system.This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Research Institute and Hospital, National Cancer Center, Goyang 410-769, Korea.

ABSTRACT
Optical imaging techniques use visual and near infrared rays. Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage. Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system. This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications. Emerging new optical imaging techniques and their potential are also described.

Show MeSH
Related in: MedlinePlus