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Are there endoscopic technologies for blood vessels?

Are there endoscopic technologies for blood vessels?


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Endoscopic procedures are used to look inside cavities like intestine, esophagus etc. Is it being used to look inside blood vessels?


Blood is hard to see through, so visualization with a camera isn't used (to my knowledge). However, Intravascular ultrasound can be used, though it is expensive and not all that common. Instead, angiography is usually used, by filling the vessels with a radio-opaque dye

There are also many techniques used to treat vascular conditions, like balloons/stents to open and keep open blocked or partially blocked vessels, or to repair valves. You can read more about Interventional cardiology or minimally invasive procedures.


Another work [1] that might be interesting to look at is the one titled as "Interactive Volume Segmentation with Threshold Field Painting". The work addresses the problem of volume segmentation mainly for blood vessels inside the brain. It is a Human-Computer Interaction (HCI) research, however, the authors used several procedures and devices to work with. Might be interesting to answer your question.

Finally, and most importantly, it might be important to you look [2] at a paper called "3D Reconstruction with Low Resolution, Small Baseline and High Radial Distortion Stereo Images". In this paper, the authors analyze and compare approaches for 3D reconstruction from low-resolution (250 x 250), high radial distortion stereo images, which are acquired with a small baseline.

[1] Takeo Igarashi, Naoyuki Shono, Taichi Kin, and Toki Saito. 2016. Interactive Volume Segmentation with Threshold Field Painting. In Proceedings of the 29th Annual Symposium on User Interface Software and Technology (UIST '16). ACM, New York, NY, USA, 403-413. DOI: https://doi.org/10.1145/2984511.2984537

[2] Tiago Dias, Helder Araujo, and Pedro Miraldo. 2016. 3D Reconstruction with Low Resolution, Small Baseline and High Radial Distortion Stereo Images. In Proceedings of the 10th International Conference on Distributed Smart Camera (ICDSC '16). ACM, New York, NY, USA, 98-103. DOI: https://doi.org/10.1145/2967413.2967435


Background

Expanding the current endoscopic optical coherence tomography (OCT) system with Doppler capability may augment this novel high-resolution cross-sectional imaging technique with functional blood flow information. The aim of this feasibility study was to assess the clinical feasibility of an endoscopic Doppler OCT (EDOCT) system in the human GI tract.

Methods

During routine endoscopy, 22 patients were imaged by using a prototype EDOCT system, which provided color-Doppler and velocity-variance images of mucosal and submucosal blood flow at one frame per second, simultaneously with high-spatial-resolution (10-25 μm) images of tissue microstructure. The images were acquired from normal GI tract and pathologic tissues.

Observations

Subsurface microstructure and microcirculation images of normal and pathologic GI tissues, including Barrett's esophagus, esophageal varices, portal hypertensive gastropathy, gastric antral vascular ectasia, gastric lymphoma, and duodenal adenocarcinoma, were obtained from 72 individual sites in vivo. Differences in vessel diameter, distribution, density, and blood-flow velocity were observed among the GI tissue pathologies imaged.

Conclusions

To our knowledge, this is the first study to demonstrate the feasibility of EDOCT imaging in the human GI tract during routine endoscopy procedures. EDOCT may detect the different microcirculation patterns exhibited by normal and diseased tissues, which may be useful for diagnostic imaging and treatment monitoring.

This work was supported by the Natural Sciences and Engineering Research Council of Canada, the Canadian Institutes for Health Research, the National Cancer Institute of Canada, the Canadian Foundation for Innovation, Photonics Research Ontario, and the Gordon Lang Foundation.


Clinical

EVH stands for Endoscopic Vessel Harvesting. During a Coronary Bypass procedure, one or more healthy blood vessels will be taken (or “harvested”) from the patient’s leg, arm or chest to be used as “new” vessels for bypass grafts. There are three techniques for harvesting a vessel from the arm or leg for a CABG procedure: open, bridging and EVH. EVH uses special instruments to view and remove a blood vessel with less trauma to the vessel or to surrounding tissues than bridging or an “open” procedure.

In the past, one long incision was made from the ankle to the groin this procedure is called an open procedure. It is highly invasive, often caused patients more pain than their chest incision, and resulted in a long scar.

An alternative, less invasive technique to the open procedure is called “bridging”. Bridging enables harvesters to gain access to the saphenous vein through three or four smaller incisions of about three inches each.


DISCUSSION

Dieulafoy’s lesion is a type of rare congenital vascular malformation, and it is also called 𠇍ieulafoy’s ulcer” or 𠇌onstant diameter artery bleeding”. The lesion can occur in any part of the gastrointestinal tract, such as the esophagus, colon, and small intestine. However, it often occurs in the lesser curvature of the stomach 6 cm from the cardioesophageal junction[5-8]. While Dieulafoy’s lesion has no specific symptoms and is not easily diagnosed, the emergent endoscopic examination is an effective means for its diagnosis. The endoscopic presentations of Dieulafoy’s lesion are as follows: (1) a superficial notch in the gastric mucosa, blood vessels in the mucosa, and coagulum on its surface (2) a focal defect of lesser curvature of stomach mucosa complicated with active bleeding (3) small arteries can protrude on the mucosa and active bleeding can occasionally be detected and (4) occasionally, blood permeation can be detected from the mucosa, and is often detected when bleeding[9-12].

The bleeding of Dieulafoy’s lesion can be unexpected, with no obvious cause. Patients often do not have other bleeding diseases such as peptic ulcers and cirrhosis, since the ruptured vessel is an artery with a constant diameter. If the bleeding is serious, patients often complain of hematemesis or hematemesis accompanied by a dark stool[13-16]. The pathogenesis of Dieulafoy’s lesion is considered as a congenital vascular malformation. Normally, the diameter of the gastrointestinal artery gradually decreases to 0.12-0.2 mm, branching to the mucosa. However, the diameter of the artery in a Dieulafoy’s lesion does not decrease it is abnormally dilated and its diameter is 0.4-4 mm. This constant arterial diameter leads to the pathology of Dieulafoy’s lesion. The abnormally dilated artery travels under the mucosa. The mucosa in Dieulafoy’s lesion is compressed and becomes ischemic, atrophied and thin. A small ulcer can form with the decay of digestive juice and friction from chyme, and if the small artery is exposed, it can rupture and bleed. The artery is often the branch of the left gastric artery therefore, the bleeding lesion is often located at the lesser curvature of the stomach 6 cm from the cardioesophageal junction[17-19]. When a small artery bleeds, blood pressure decreases, and vasoconstriction and thrombosis occur in the bleeding artery. Bleeding can temporarily stop and the artery is invisible when bleeding stops. It might not be detec by endoscopic examination, even with a surgical operation. If blood pressure rises to normal or the blood clot is shed, serious bleeding can reoccur.

Generally, it is considered that medical treatment plays a minor role in the treatment of Dieulafoy’s lesion endoscopic therapy and surgery are often performed. The use of pituitrin and somatostatin causes bowel vessels to contract and blood flow to decrease, and these drugs are used for endoscopic therapy and surgical operations. The Dieulafoy’s lesion before the 1980’s was mainly treated with surgical operations. Since Boron first successfully treated 3 cases of Dieulafoy’s lesion in 1987 with the endoscopic therapy[20], an increasing number of doctors have treated this lesion with endoscopic therapy. The death rate decreased from 60%-70% to 20%. Endoscopic treatment has the advantages of being simple in operation, which is easily replicated, is microtraumatic, safe and useful, and it can be performed during the examination. Methods used include injection beneath the mucosa, electric coagulation, laser, heat probe, microwaves, ligation and hemoclips. The efficacy was reported to be more than 80%[21-28].

Three types of endoscopic therapy were used in this study for the treatment of bleeding due to Dieulafoy’s lesion. Aethoxysklerol injection therapy can result in sclerosis and emphraxis to prevent re-bleeding. Local tissue edema occurred and the surrounding pressure of the bleeding site increased when aethoxysklerol was injected. The artery was compressed and thrombosis occurred in the vessel. When aethoxysklerol was injected around the vessel, edema and inflammation rapidly occurred, with fibroblast proliferation. Forty-six cases received this type of therapy and the rate of successful hemostasis was 71.7% (33/46). We also treated patients with endoscopic hemoclip hemostasis. The mechanism of hemoclip hemostasis is similar to that of surgical vascular suturing. In our study, 31 cases received this type of therapy, and the rate of successful hemostasis was 77.4% (24/31). The third method we used in this study was a combined therapy of hemoclip hemostasis with injection of aethoxysklerol. Thirty cases received this therapy, and the rate of successful hemostasis was 96.7% (29/30). We found that this combined therapy was the most effective method for stopping bleeding from a Dieulafoy’s lesion, and it could effectively reduce the re-bleeding rate as well.

Hemoclip hemostasis is widely used for non-variceal active bleeding, and it is indicated for Dieulafoy’s lesion[29,30]. Our study used the following procedure. A clip was assembled on the delivery device. When a bleeding lesion was detected, the delivery device was inserted into the endoscopic working channel to push it to the anterior extremity of the endoscope. The clip was stretched out of the endoscope, and then the clip was stretched open to the largest width (1.2 cm). The direction of the clip could be adjusted with the rotating device on the delivery system. The stretched clip was collimated to the lesion, the gliding lug on the device was pushed back, and the clip was locked. The clip was then released and the delivery device was pulled out. One clip was used for ordinary lesions, and for larger lesions, 2-3 clips were needed. We believe that the key points for successful clipping are as follows: (1) the lesion needs to be directly observed (2) the lesion and its surrounding tissue should be fully exposed, and the angle of the clip and bleeding site should be in a range of 45-90° and (3) the depth of the clip should be considered. The optimal depth is where the exposed vessel and deep tissue are able to be clipped. The clip should not be superficial, and if it is superficial, the clip can come off in a short period, and then re-bleeding is inevitable. The clip often releases automatically in 1-3 wk. It is mixed with food debris and the stool, and it is then eliminated from the body. This method is considered as microtraumatic. If it is not successful at the first time, it can be replicated. Even if it fails, it can mark the bleeding site, thereby making the surgical operation easier, and avoiding blind resection. This method is effective for the treatment of Dieulafoy’s lesion, and it is increasingly recognized by doctors. We found that if aethoxysklerol was injected after clipping, the re-bleeding rate in Dieulafoy’s lesion was effectively decreased.


New technology gives unprecedented look inside capillaries

An image of capillaries taken with a new technology from Vadim Backman's lab. Credit: Northwestern University

More than 40 billion capillaries—tiny, hair-like blood vessels—are tasked with carrying oxygen and nutrients to the far reaches of the human body. But despite their sheer number and monumental importance to basic functions and metabolism, not much is known about their inner workings.

Now a Northwestern University team has developed a new tool that images blood flow through these tiny vessels, giving insight into this central portion of the human circulatory system. Called spectral contrast optical coherence tomography angiography (SC-OCTA), the 3-D-imaging technique can detect subtle changes in capillary organization for early diagnosis of disease.

"There has been a progressive push to image smaller and smaller blood vessels and provide more comprehensive, functional information," said Vadim Backman, who led the study. "Now we can see even the smallest capillaries and measure blood flow, oxygenation and metabolic rate."

The paper was published last week in the journal Light: Science and Applications. Backman is the Walter Dill Scott Professor of Biomedical Engineering in Northwestern's McCormick School of Engineering. He co-leads the Cancer and Physical Sciences Research Program at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

Researchers and physicians have long been able to see inside major veins and arteries with Doppler ultrasound, which uses high-frequency sound waves to measure blood flow. But this insight does not give a full picture of the circulatory system. Unlike veins and arteries, capillaries are responsible for oxygen exchange, or delivering oxygen to organs and tissues throughout the body while shuttling carbon dioxide away. Low blood oxygen can cause mild problems such as headaches to severe issues such as heart failure.

"You can have great blood flow through arteries and still have absolutely no blood sending oxygen to tissues if you don't have the right microvasculature," Backman said. "Oxygen exchange is important to everything the body does. But many questions about what happens in microvasculature have gone unanswered because there was no tool to study them. Now we can tackle that."

"SC-OCTA is a valuable diagnostic tool," added James Winkelmann, a graduate student in Backman's laboratory and the study's first author. "We can now detect alterations to capillary organization, which is evident in a variety of conditions ranging from cancer to cardiovascular disease. Detecting these diseases earlier has the potential to save lives."

Researchers have had difficulties peering inside capillaries because of the vessels' microscopic size. A single capillary is a mere 5-10 microns in diameter—so small that red blood cells must flow through in single file.

SC-OCTA works by combining spectroscopy, which looks at the various visible light wavelengths, or color spectra, with conventional optical coherence tomography (OCT), which is similar to ultrasound except uses light waves instead of sound waves. Like a radar, OCT pinpoints the tissue of interest, and then spectroscopy characterizes it.

SC-OCTA has many advantages over traditional imaging: it does not rely on injected dyes for contrast or harmful radiation. Many types of imaging also only work if the area of interest is moving (for example, ultrasound can only image blood when it is flowing) or completely still. SC-OCTA can take a clear picture of both. This enables it to image stagnant blood or moving organs, such as a beating heart.

"It can measure blood flowing regardless of how fast it goes, so motion is not a problem," Backman said.

"SC-OCTA's unique ability to image non-flowing blood could also become a valuable tool for the booming field of organoids, which studies how organs develop and respond to disease," Winkelmann said. "I am excited to start exploring all the applications."

The new technology's only limitation is that it cannot image deeper than 1 millimeter. This might seem shallow compared to ultrasound, which can see several centimeters below the surface. Backman said this can be remedied by putting the tool on the end of an endoscopic probe. By inserting it into the body, the tool can image organs up-close. That is something that his laboratory is working on now.

The title of the paper is "Spectral contrast optical coherence tomography angiography enables single-scan vessel imaging.:


Endoscopic Solutions

Bleeding is the most frequent complication during endoscopic procedures 1 .

For intra-procedural bleeds, some solutions such as clips and cauterisation are not suitable for the location of the bleeding, particularly in small difficult to reach areas. Maintaining clear visibility during haemostasis is important, especially when working within a tight enclosed space.

There is also a risk of delayed bleeding following endoscopic procedures, especially after endoscopic submucosal dissection (ESD). If untreated, delayed bleeding can lead to serious conditions such as haemorrhagic shock 1 .

The Benefits of PuraStat ®

PuraStat ® is an easy-to-use, transparent hydrogel that enables precise work in a narrow space without any compromising the view during endoscopic procedures. It is inert, non-adhesive and easily deliverable through an endoscopic applicator. PuraStat can also add value when used in combination with clips and cauterization.

PuraStat has also been proven to reduce the rate of delayed bleeding following colonic ESD by 50% 2 .

For application within gastro-enterology, PuraStat is indicated 3 for:

  • Achieving haemostasis in bleeding from small blood vessels and oozing from capillaries of the GI tract following surgical procedures [when haemostasis by ligation or standard means is insufficient or impractical]
  • Reduction of delayed bleeding following gastrointestinal endoscopic submucosal dissection (ESD) procedures in the colon.

“In addition to its efficacy in stopping bleeding, we found more advantageous properties of [PuraStat]*, especially during endoscopic surgery. First, [PuraStat]* is a clear material. It does not block the field of view, which is particularly important during endoscopic surgery. Second, [PuraStat]* is applied as a solution and only gelates when in contact with body fluids, making it easy to apply.” 4

*In this study the name PuraMatrix is erroneously used instead of PuraStat

“PuraStat is [a] very helpful new tool in haemostasis that allows successful application also in such special bleeding sites as the duodenal papilla, where clipping is very difficult/dangerous because of the orifice of pancreatic and bile duct.

PuraStat is very easy to use.”

Professor Jens Tischendorf, M.D.

Department of Internal Medicine und Gastroenterology, Rhein-Maas Hospital, Würselen, Germany

Important Note: The IFU-002 rev2.2 is currently approved only in Europe. The current IFU outside of Europe depends on the registration status. The approved indication can differ in your country, please contact 3-D Matrix if you need any additional information on device indication.


CONCLUSION

In conclusion, several aspects of optimal serum levels demanded by IBD under biologic agents require deep investigation in the future. First, whether the discrepancy of optimal serum level in complicated phenotype or simple phenotype exists or not should be investigated. Second, how much maintenance time and serum levels of biologic agents are still needed to prevent IBD from disease flare after identification of deep remission. Furthermore, the achievement of deep remission in the prognosis of IBD patients should be evaluated in the future during the induction phase by combining with the serum level of biologics and patient characteristics. Finally, non-responders of IBD patients in the initial phase of biological treatment are considered appropriate to optimize the serum levels tentatively by increasing the injection dose, shortening the interval time of injection, or converting the type of biologics. Also the variation in serum levels during optimization period of biological therapy should be emphasized on therapeutic drug monitoring.


Are there endoscopic technologies for blood vessels? - Biology

Mingjian Sun is an associate professor at Harbin Institute of Technology, Weihai, China. He received B.E. degree from Harbin Institute of Technology in 2003, and Ph.D degree from Harbin Institute of Technology in 2011, respectively. His main research interests include photoacoustic imaging technology, artificial intelligence medicine and its clinical translation

Chao Li is currently pursuing his Master's degree in the School of School of Information Science and Engineering, Harbin Institute of Technology, Weihai, China. His research interests include photoacoustic endoscopy imaging and medical image processing.

Ningbo Chen is a research assistant at Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences, Chinese Academy of Sciences. He received his Master's degree in Mechanical Engineering from Guangzhou University in 2019. His research interests include developing novel biomedical imaging tools based on photoacoustic imaging for preclinical and clinical applications.

Huangxuan Zhao received his bachelor’s degree in mechanical engineering from Wuhan University of Technology in 2013, and PhD degree in the Department of Biomedical Engineering at Capital Medical University in China. His research interests include utilizing photoacoustic imaging for the detection of diseases and developing new surgical guidance methods for clinical applications.

Liyong Ma is an associate professor at Harbin Institute of Technology, Weihai, China. He received B.E. degree from Harbin Institute of Technology in 1993, and Ph.D degree from Harbin Institute of Technology in 2007, respectively. His main research interests include medical imaging and artificial intelligence.

Chengbo Liu is an Associate Professor at Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences, Chinese Academy of Sciences. He received both his Ph.D and Bachelor degree from Xiɺn Jiaotong University, each in 2012 in Biophysics and 2007 in Biomedical Engineering. During his Ph.D. training, he spent two years doing tissue spectroscopy research at Duke University as a visiting scholar. Now he is an associate professor at SIAT, working on multi-scale photoacoustic imaging and its translational research.

Yi Shen is a professor and a PhD candidate supervisor at Harbin Institute of Technology, China. His interest includes automatic control technology and ultrasound imaging technology, such as intelligent detection, ultrasonic beam forming and ultrasound image processing.


New technology gives unprecedented look inside capillaries

EVANSTON, Ill. --- More than 40 billion capillaries -- tiny, hair-like blood vessels -- are tasked with carrying oxygen and nutrients to the far reaches of the human body. But despite their sheer number and monumental importance to basic functions and metabolism, not much is known about their inner workings.

Now a Northwestern University team has developed a new tool that images blood flow through these tiny vessels, giving insight into this central portion of the human circulatory system. Called spectral contrast optical coherence tomography angiography (SC-OCTA), the 3D-imaging technique can detect subtle changes in capillary organization for early diagnosis of disease.

"There has been a progressive push to image smaller and smaller blood vessels and provide more comprehensive, functional information," said Vadim Backman, who led the study. "Now we can see even the smallest capillaries and measure blood flow, oxygenation and metabolic rate."

The paper was published last week in the journal Light: Science and Applications. Backman is the Walter Dill Scott Professor of Biomedical Engineering in Northwestern's McCormick School of Engineering.

Researchers and physicians have long been able to see inside major veins and arteries with Doppler ultrasound, which uses high-frequency sound waves to measure blood flow. But this insight does not give a full picture of the circulatory system. Unlike veins and arteries, capillaries are responsible for oxygen exchange, or delivering oxygen to organs and tissues throughout the body while shuttling carbon dioxide away. Low blood oxygen can cause mild problems such as headaches to severe issues such as heart failure.

"You can have great blood flow through arteries and still have absolutely no blood sending oxygen to tissues if you don't have the right microvasculature," Backman said. "Oxygen exchange is important to everything the body does. But many questions about what happens in microvasculature have gone unanswered because there was no tool to study them. Now we can tackle that."

"SC-OCTA is a valuable diagnostic tool," added James Winkelmann, a graduate student in Backman's laboratory and the study's first author. "We can now detect alterations to capillary organization, which is evident in a variety of conditions ranging from cancer to cardiovascular disease. Detecting these diseases earlier has the potential to save lives."

Researchers have had difficulties peering inside capillaries because of the vessels' microscopic size. A single capillary is a mere 5-10 microns in diameter -- so small that red blood cells must flow through in single file.

SC-OCTA works by combining spectroscopy, which looks at the various visible light wavelengths, or color spectra, with conventional optical coherence tomography (OCT), which is similar to ultrasound except uses light waves instead of sound waves. Like a radar, OCT pinpoints the tissue of interest, and then spectroscopy characterizes it.

SC-OCTA has many advantages over traditional imaging: it does not rely on injected dyes for contrast or harmful radiation. Many types of imaging also only work if the area of interest is moving (for example, ultrasound can only image blood when it is flowing) or completely still. SC-OCTA can take a clear picture of both. This enables it to image stagnant blood or moving organs, such as a beating heart.

"It can measure blood flowing regardless of how fast it goes, so motion is not a problem," Backman said.

"SC-OCTA's unique ability to image non-flowing blood could also become a valuable tool for the booming field of organoids, which studies how organs develop and respond to disease," Winkelmann said. "I am excited to start exploring all the applications."

The new technology's only limitation is that it cannot image deeper than 1 millimeter. This might seem shallow compared to ultrasound, which can see several centimeters below the surface. Backman said this can be remedied by putting the tool on the end of an endoscopic probe. By inserting it into the body, the tool can image organs up-close. That is something that his laboratory is working on now.

The title of the paper is "Spectral contrast optical coherence tomography angiography enables single-scan vessel imaging. The research was supported by the National Science Foundation and the National Institutes of Health (award numbers R01CA200064, R01CA183101, R01CA173745 and R01CA165309).

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