Although various clinical imaging modalities have been developed to visualize internal body structures and detect abnormal tissues prior to surgical procedures, most medical imaging modalities do not provide disease-specific images in real-time. Optical imaging can provide the surgeon with real-time visualization of the surgical field for intraoperative image-guided surgery. Imaging in the near-infrared (NIR) window (650-900 nm), also known as the “therapeutic window” has high potential by offering low absorbance and scattering in tissues resulting in minimized background autofluorescence. Clinically, optical fluorescence imaging with the targeted contrast agents provides opportunities for significant advances in intraoperative image-guided surgery. There are only two clinically available NIR fluorophores, indocyanine green (ICG) and methylene blue (MB), that support the image-guided surgery. However, neither of them perform in vivo by providing optimum specificity and stability for targeted image guidance. Therefore, it is of paramount importance to develop targeted NIR fluorophores for unmet clinical needs. Using the right combination of an NIR fluorescence imaging system and a targeted fluorophore, the desired target tissues can be imaged to provide real-time fluorescence guidance without changing the field-of-view during surgery. Thus, in a clinical discipline, the development of NIR fluorophores for ‘structure-inherent targeting’ is an unmet need for early phase diagnostics with accurate targeting.
Contrast Media ; Diagnostic Imaging ; Fluorescence ; Fluorescent Dyes ; Indocyanine Green ; Methylene Blue ; Optical Imaging ; Sensitivity and Specificity ; Surgery, Computer-Assisted

BACKGROUND: For the bone-specific imaging, a structure-inherent targeting of bone tissue recently has been reported a new strategy based on incorporation of targeting moieties into the chemical structure of near-infrared (NIR) contrast agents, while conventional methods require covalent conjugation of bone-targeting ligands to NIR contrast agents. This will be a new approach for bone-targeted imaging by using the bifunctional NIR contrast agents. METHODS: The goal of this review is to provide an overview of the recent advances in optical imaging of bone tissue, highlighting the structure-inherent targeting by developing NIR contrast agents without the need for a bone-targeting ligand such as bisphosphonates. RESULTS: A series of iminodiacetated and phosphonated NIR contrast agents for the structure-inherent targeting of bone tissue showed excellent bone-targeting ability in vivo without non-specific binding. Additionally, the phosphonated NIR contrast agents could be useful in the diagnosis of bone metastasis. CONCLUSION: By developing bone-targeted NIR contrast agents, optical imaging of bone tissue makes it very attractive for preclinical studies of bone growth or real-time fluorescence guided surgery resulting in high potential to shift the clinical paradigms.
Bone and Bones ; Bone Development ; Contrast Media ; Diagnosis ; Diphosphonates ; Fluorescence ; Ligands ; Neoplasm Metastasis ; Optical Imaging ; Surgery, Computer-Assisted

Endoscopic variceal ligation is the preferred endoscopic treatment method for esophageal variceal bleeding. The incidence of complications such as chest pain, bleeding, stricture formation, and aspiration pneumonia is low. We report a case wherein a malfunctioning multiple-band ligator could have potentially caused damage to the esophageal varices and massive bleeding. The equipment was safely removed using scissors and forceps. To the best of our knowledge, this is the first published report detailing the management of a case of esophageal variceal bleeding.