Neoplasms is one of the main diseases for harming health. It is difficult to prevent the neoplasms because the factors of bringing out them are complex. To raise survival rate the early diagnosis of tumors is very imp...Neoplasms is one of the main diseases for harming health. It is difficult to prevent the neoplasms because the factors of bringing out them are complex. To raise survival rate the early diagnosis of tumors is very important. Radionuclide imaging is useful to detect recurrent or residual disease and to identify benign or malignant tumor. Several tumor imaging agents as following have clinical significance in diagnosing tumors.展开更多
Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit freq...Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies.For perfusion imaging,markers have been designed to enhance the contrast in B-mode imaging.These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells.In this review,the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described.Furthermore,an outline of clinical imaging applications of contrast-enhanced ultrasound is given.It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition,and how these phenomena may be utilized in ultrasonic imaging.Aided by high-speed photography,our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques.More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves,and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs.These are beginning to be accepted into clinical practice.In the long term,targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.展开更多
Contrast agents are increasingly being used to characterize the vasculature in an organ of interest,to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures.We rev...Contrast agents are increasingly being used to characterize the vasculature in an organ of interest,to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures.We review the mechanisms of action of first,second and third generation contrast agents and their use in various endoscopic procedures in the gastrointestinal tract.Various applications of contrast-enhanced endoscopic ultrasonography include differentiating benign from malignant mediastinal lymphadenopathy,assessment of depth of invasion of esophageal,gastric and gall bladder cancers and visualization of the portal venous system and esophageal varices.In addition,contrast agents can be used to differentiate pancreatic lesions.The use of color Doppler further increases the ability to diagnose and differentiate various pancreatic malignancies.The sensitivity of power Doppler sonography to depict tumor neovascularization can be increased by contrast agents.Contrast-enhanced harmonic imaging is a useful aid in identifying the tumor vasculature and studying pancreatic microperfusion.In the future,these techniques could potentially be used to quantify tumor perfusion,to assess and monitor the efficacy of antiangiogenic agents,to assist targeted drug delivery and allow molecular imaging.展开更多
Distinguishing a tumor from non-neoplastic tissue is a challenging task during cancer surgery. Several attempts have been made to use visible or fluorescent agents to aid in the visualization of a tumor during surgery...Distinguishing a tumor from non-neoplastic tissue is a challenging task during cancer surgery. Several attempts have been made to use visible or fluorescent agents to aid in the visualization of a tumor during surgery. We describe a novel method to delineate brain tumors, using a highly sensitive photoacoustic imaging technique that is enhanced by tumor-targeting blue nanoparticles serving as a contrast agent. Experiments on phantoms and on rat brains, ex vivo, demonstrate the high sensitivity of photoacoustic imaging in delineating tumors containing contrast agent at a concentration much lower than needed for visualization by the naked eye. The limit of detection of the system for the nanoparticles is about 0.77 μg/mL in water （equivalent to 0.84 μmol/L Coomassie Blue dye）. The present exploratory study suggests that photoacoustic imaging, when used with strongly optical absorbing contrast agents, could facilitate cancer surgery intraoperatively by revealing the distribution and extent of the tumor.展开更多
Brain cancer is one of the most lethal and difficult-to-treat cancers because of its physical location and biological barriers. The mainstay of brain cancer treatment is surgical resection, which demands precise imagi...Brain cancer is one of the most lethal and difficult-to-treat cancers because of its physical location and biological barriers. The mainstay of brain cancer treatment is surgical resection, which demands precise imaging for tumor localization and delineation. Thanks to advances in bioimaging, brain cancer can be detected earlier and resected more reliably. Magnetic resonance imaging（MRI） is the most common and preferred method to delineate brain cancer, and a contrast agent is often required to enhance imaging contrast.Dendrimers, a special family of synthetic macromolecules,constitute a particularly appealing platform for constructing MRI contrast agents by virtue of their well-defined three-dimensional structure, tunable nanosize and abundant surface terminals, which allow the accommodation of high payloads and numerous functionalities. Tuning the dendrimer size,branching and surface composition in conjunction with conjugation of MRI functionalities and targeting moieties can alter the relaxivity for MRI, overcome the blood-brain barrier and enhance tumor-specific targeting, hence improving the imaging quality and safety profile for precise and accurate imaging of brain tumors. This short review highlights the recent progress, opportunities and challenges in developing dendrimer-based MRI contrast agents for brain tumor imaging.展开更多
文摘Neoplasms is one of the main diseases for harming health. It is difficult to prevent the neoplasms because the factors of bringing out them are complex. To raise survival rate the early diagnosis of tumors is very important. Radionuclide imaging is useful to detect recurrent or residual disease and to identify benign or malignant tumor. Several tumor imaging agents as following have clinical significance in diagnosing tumors.
文摘Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies.For perfusion imaging,markers have been designed to enhance the contrast in B-mode imaging.These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells.In this review,the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described.Furthermore,an outline of clinical imaging applications of contrast-enhanced ultrasound is given.It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition,and how these phenomena may be utilized in ultrasonic imaging.Aided by high-speed photography,our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques.More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves,and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs.These are beginning to be accepted into clinical practice.In the long term,targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.
文摘Contrast agents are increasingly being used to characterize the vasculature in an organ of interest,to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures.We review the mechanisms of action of first,second and third generation contrast agents and their use in various endoscopic procedures in the gastrointestinal tract.Various applications of contrast-enhanced endoscopic ultrasonography include differentiating benign from malignant mediastinal lymphadenopathy,assessment of depth of invasion of esophageal,gastric and gall bladder cancers and visualization of the portal venous system and esophageal varices.In addition,contrast agents can be used to differentiate pancreatic lesions.The use of color Doppler further increases the ability to diagnose and differentiate various pancreatic malignancies.The sensitivity of power Doppler sonography to depict tumor neovascularization can be increased by contrast agents.Contrast-enhanced harmonic imaging is a useful aid in identifying the tumor vasculature and studying pancreatic microperfusion.In the future,these techniques could potentially be used to quantify tumor perfusion,to assess and monitor the efficacy of antiangiogenic agents,to assist targeted drug delivery and allow molecular imaging.
基金Acknowledgements This work was supported by National Institutes of Health （NIH） grant No. R33CA125297 （RK） and National Natural Science Foundation of China （NSFC） grant No. 11028408 （XW）. We thank Dr. Z. Xie and Dr, J. Rajian for their help during photoacoustic imaging. We also like to extend our sincere thanks to Dr. M. Nie for his help during nanoparticle synthesis. We would also like to thank Mr. Dah-Luen Huang for developing the BTW in the rats.
文摘Distinguishing a tumor from non-neoplastic tissue is a challenging task during cancer surgery. Several attempts have been made to use visible or fluorescent agents to aid in the visualization of a tumor during surgery. We describe a novel method to delineate brain tumors, using a highly sensitive photoacoustic imaging technique that is enhanced by tumor-targeting blue nanoparticles serving as a contrast agent. Experiments on phantoms and on rat brains, ex vivo, demonstrate the high sensitivity of photoacoustic imaging in delineating tumors containing contrast agent at a concentration much lower than needed for visualization by the naked eye. The limit of detection of the system for the nanoparticles is about 0.77 μg/mL in water （equivalent to 0.84 μmol/L Coomassie Blue dye）. The present exploratory study suggests that photoacoustic imaging, when used with strongly optical absorbing contrast agents, could facilitate cancer surgery intraoperatively by revealing the distribution and extent of the tumor.
基金Financial support from La Ligue Nationale Contre le Cancer (EL2016.LNCC/LPP to Peng L, PhD fellowship to Lyu Z)the French National Research Agency under the frame of EuroNano Med Ⅱ (ANR-15-ENM2-0006-02, ANR-16-ENM2-0004-02) (Peng L)+1 种基金the Campus France ORCHID program (Peng L, Kao CL)China Scholarship Council (Ding L)
文摘Brain cancer is one of the most lethal and difficult-to-treat cancers because of its physical location and biological barriers. The mainstay of brain cancer treatment is surgical resection, which demands precise imaging for tumor localization and delineation. Thanks to advances in bioimaging, brain cancer can be detected earlier and resected more reliably. Magnetic resonance imaging（MRI） is the most common and preferred method to delineate brain cancer, and a contrast agent is often required to enhance imaging contrast.Dendrimers, a special family of synthetic macromolecules,constitute a particularly appealing platform for constructing MRI contrast agents by virtue of their well-defined three-dimensional structure, tunable nanosize and abundant surface terminals, which allow the accommodation of high payloads and numerous functionalities. Tuning the dendrimer size,branching and surface composition in conjunction with conjugation of MRI functionalities and targeting moieties can alter the relaxivity for MRI, overcome the blood-brain barrier and enhance tumor-specific targeting, hence improving the imaging quality and safety profile for precise and accurate imaging of brain tumors. This short review highlights the recent progress, opportunities and challenges in developing dendrimer-based MRI contrast agents for brain tumor imaging.
