Ultrasound endoscopy is a combination of medical endoscopy technology and high-frequency ultrasound technology, i.e., a special endoscope with a miniature ultrasound probe mounted on the tip. Endoscopic ultrasonography (EUS) is the process of using this special endoscopic device to perform intracavitary ultrasound investigation of suspicious lesions in cavernous organs or adjacent organ structures to improve the ability to determine the nature and depth of lesions by detecting lesions at all levels of the organ wall and adjacent organs.
Color Doppler endoscopy (endoscopie color Doppler ultrasonography (ECDUS)) is able to show the local blood flow signal around the area, further improving the correctness of diagnosis and expanding the scope of application. The ability of high-resolution EUS to show the five layers of the GI tract is almost comparable to that of microscopy, which is not possible with other detection techniques such as MRI and CT. In the early 1990s, with the birth of convex line array ultrasound endoscopy, the technique of mediated human ultrasound endoscopy developed rapidly, and the techniques of ultrasound endoscopy-mediated puncture, drainage and mucosal resection emerged.
1.EUS-mediated puncture techniques
(1) EUS-guided fine needle aspiration biopsy technique
(EUS-guided fine needle aspiration, EUS-FNA) This is an early developed EUS interventional technique, i.e., using ultrasound endoscopy to observe and track the fine needle for puncture and aspiration biopsy of suspicious lesions, and at the same time, it can be combined with Doppler signals to show the direction, flow and speed of blood and improve the FNA safety. It is currently more maturely used in.
①needle aspiration biopsy of paraesophageal lymph nodes;
(ii) Needle aspiration puncture of occupying pancreatic lesions;
③ Needle aspiration of mediastinal tumor;
Weynand et al. reported that the sensitivity of EUS-FNA for pancreatic masses was 85%, the specificity was 90%-100%, the positive prediction rate was 98%-100%, the negative prediction rate was 44%-80%, and the accuracy was 75%-84%. Compared with extracorporeal ultrasound and CT-guided puncture biopsy, EUS-FNA has a higher success rate because the puncture is performed from within the lumen, the puncture distance is shorter, and factors such as subcutaneous fat, air in the intestinal cavity and ascites are avoided, the puncture site can be accurately located, and important vessels can be avoided.
Larghi et al. performed EUS-guided Tmcut needle aspiration biopsy in 23 patients with pancreatic parenchymal masses detected by radiological examination, and the results showed that pancreatic tissue was successfully obtained in 17/23 cases with an overall diagnostic accuracy of 61%, and in 16 patients with successful biopsy and follow-up, the diagnostic accuracy was 87.5% with no complications.
Newly, Will et al. reported a patient with a septic infection in the mediastinum and formation of an esophageal mediastinal fistula caused by fine needle puncture of enlarged lymph nodes in the mediastinum, which was mediated by ultrasound endoscopy and placement of a drainage tube, resulting in infection control and closure of the fistula, avoiding surgical intervention. It is suggested that ultrasound endoscopy-guided interventions may be considered first in cases of infection caused by intraluminal fine needle aspiration biopsy because of their minimal invasiveness and significant efficacy.
(2) EUS-guidedfine needle injection (EUS-FNI)
It is a technique of EUS-mediated injection of drugs or immune agents into the lesion through a puncture needle to achieve the desired therapeutic purpose. Earlier, EUS-guided injection of botulinum toxin was reported for the treatment of cardia incontinentia. After the smooth muscle layer of the esophageal sphincter was revealed by ultrasound endoscopy, 1 ml of botulinum toxin (total dose 80-100 U) was injected in 4 different quadrants by inserting a fine needle in the biopsy orifice, and 4 patients were treated with 5-13 (mean 8.8) months of follow-up without 1 recurrence of dysphagia. The advantage of this technique is that the drug can be accurately injected into the smooth muscle layer of the esophageal wall, which can block the neuromuscular junction to the maximum extent, reduce the recurrence rate, reduce the drug dosage, and thus prevent the production of antitoxin antibodies after repeated injections of botulinum toxin.
Chang et al5 reported 8 patients with inoperable resectable pancreatic cancer, in which allogeneic mixed lymphocyte cultures were accurately injected into the pancreatic cancer mass with a puncture needle under ultrasound endoscopic guidance, and the results showed that the tumor shrank in 3 patients with a median survival of 13.2 (4.2-36) months, and the postoperative reactions such as hypothermia (7/8), gastrointestinal symptoms (3/8) and elevated bilirubin (3/8) were controlled with symptomatic management. Other injection treatment techniques include EUS-mediated injection of chemicals such as anhydrous alcohol into the local tumor to cause necrosis and thereby achieve resection. In addition, EUS-mediated local injection of modified viruses for the treatment of advanced pancreatic cancer has also been reported.
(3) EUSguided celiac plexus neurolysis (EUS-CPN)
This technique is essentially an EUS-mediated fine needle injection technique. It is used to chemically cut off visceral sensory nerves and relieve pain by injecting chemicals into the celiac plexus from the cavity through the mediation of EUS, causing necrosis. It is reported that 70% to 90% of pancreatic cancer patients can have pain relief for about 3 months after the 1st EUS.CPN treatment. Compared with the traditional percutaneous puncture method, EUS-CPN has a short puncture distance from the anterior approach and can avoid important blood vessels, with relatively high accuracy of puncture and injection and minimal complication rate.
Gress et al. showed that in 5 of 10 patients who underwent EUS-CPN, there was a significant reduction in the amount of painkillers, and the average postoperative follow-up ranged from 15 (8 to 24) weeks, with pain relief reaching 8 weeks in 40% of patients and 24 weeks in 30% of patients. This shows that EUS.CPN is a treatment for pancreatic cancer and chronic pancreatitis caused by
CPN is a safe, effective and economical method for the treatment of intractable abdominal pain caused by pancreatic cancer and chronic pancreatitis.
(4) EUS-guidedradiofrequency ablation (EUS/RFA)
The EUS-guided radiofrequency ablation technique is a safe, effective and economical method for the treatment of small pancreatic endocrine tumors and for the treatment of unresectable pancreatic cancer by stabbing a puncture needle with a radiofrequency generator into the tumor tissue and then using radiofrequency to cause necrosis of the tumor tissue. form limited, well-defined
coagulative necrotic foci in normal pancreatic tissue. In addition to radiofrequency energy, EUS-mediated resection with radioactive energy has also been used to treat anal cancer. In addition, laser, microwave, and freezing methods are also available for EUS-guided lesion excision. These EUS-mediated antitumor treatments will certainly have a profound impact in clinical applications.
2.EUS-mediated drainage techniques
(1) EUSguided pancreatic pseudocyst drainage technology (EUSguided pancreatic pseudocyst drainage)
This technique is used to find the best puncture point between the pseudocyst and the gastrointestinal tract through EUS-mediated puncture and fistula, and place an internal stent to drain the cyst contents to the gastrointestinal tract through the stent. In the case of pseudocystic tumors complicated by infection, a nasocystic drainage tube (nasocysticdrainage) can be placed and the cystic cavity can be flushed with antibiotics, and after the infection is controlled, the internal stent can be replaced and the drainage can be continued to make the cyst disappear. Currently
As long as the cyst is mature and the shortest distance between the cyst wall and the wall of the gastrointestinal tract is less than 1 cm, even if the cyst does not protrude into the gastric cavity and cause compression, puncture and drainage can be performed under EUS guidance. According to the available literature, the effective rate is over 90%, and the pseudocysts of most patients start to shrink around 2 weeks after surgery and disappear around 4 months. giovannini et al.
mediated placement of nasal cyst drains in 20 patients with pancreatic abscesses (2 failed and surgery was performed) and stents or nasal cyst drains in 15 patients with pancreatic pseudocysts. The success rate of EUS-mediated drainage was 88.5% (31/35), which is less invasive, with fewer complications such as bleeding and perforation, and more effective than the traditional surgical approach. It can replace surgery in some elective cases.
(2) EUS-mediated pancreatic duct drainage (EUSassistedpancreatic duct drainage)
The ultrasound endoscopy-mediated pancreatic duct drainage has also been reported. Francois et al. performed Eus-mediated pancreatic duct puncture via the gastric route and placed gastro-pancreatic duct stents in four patients with chronic pancreatitis who had painful symptoms due to dilation of the pancreatic duct caused by pancreatic duct obstruction.
Recently, Will et al. reported that a puncture needle was inserted into the pancreatic duct through the gastric wall under EUS guidance, followed by a guidewire into the pancreatic duct and through the papilla into the duodenum, which was dragged out by the duodenoscope, and then the papilla was routinely cut open to reconstruct the patient tolerated the intervention well. The above method is a practical and less invasive method for patients with mechanical obstruction of the pancreatic duct caused by chronic pancreatitis and who have failed the conventional papillary drainage treatment plan.
(3) EUS-mediated bile duct. Duodenal tube placement and drainage technique
(EUS-guided bilioduodenal anastomosis) For obstructive jaundice, endoscopic retrograde cholangiopancreatography (ERCP) with stent placement is the conventional treatment option for reducing jaundice. However, ERCP has a failure rate of 10%-15%, and Giovannini et al. have performed EUS-mediated biliary tract. Duodenal
In a patient with obstructive xanthogranuloma who failed conventional ERCP, the duodenal wall was incised with an F-needle endoscope (FG38x) under the guidance of therapeutic ultrasound endoscopy to access the common bile duct, and after successful imaging, the incision was removed and a guidewire was inserted. This technique is of great practical value in patients with obstructive jaundice whose drainage problems cannot be resolved by conventional ERCP.
(4) EUS-guided drainage of ‘deep pelvic abscesses’ (EUS-guided drainage of ‘deep pelvic abscesses’)
In addition to these site lesions that can be drained under EUS-mediated drainage, Giovannini et al¨41 performed EUS-mediated drainage of 12 patients with perirectal/pelvic abscesses without significant complications during treatment. In 9 of these patients, a stent was successfully placed transrectally, while the other 3 could only be treated with pus aspiration. During the subsequent follow-up of 6-14 (mean 10.6) months, the abscess was completely drained in 8 patients with stent placement and the stent was removed after 3-6 months; only 1 patient underwent surgical drainage because the abscess was too large and incomplete. 2 of the 3 patients who underwent drainage underwent surgery for recurrence of the abscess. Therefore, deep pelvic abscesses caused by surgery can be treated by EUS-mediated drainage technique, thus avoiding another surgical intervention.
3.EUS-mediated mucosal resection technique
Endoscopic mucosal resection (EMR) is a major advancement in the endoscopic treatment of superficial lesions in esophagus, stomach and colorectum, which can avoid surgery for many patients. Bergmann et al. used EUS in 57 patients with non-polypoid colorectal lesions to detect the site, shape, and level of tumor involvement.
The site, shape, size and depth of lesions were examined by EUS and endoscopic mucosal resection was performed in 57 patients with non-polyposis colorectal lesions. The results showed that complete resection was achieved in 59 of 6l benign lesions (adenomas) and 6 of 8 malignant lesions (early carcinomas). During the subsequent follow-up period of 6 to 30 (mean 18) months, 2 of the 59 adenomas recurred, while none of the 6 early-stage cancers recurred. In another study conducted over the course of 4 years, Wehrmann et al. performed a study of 20 adenomas that were resected via a small
In another 4-year study, Wehrmann et al. performed endoscopic tumor resection in 20 patients with submucosal esophageal tumors (less than 4 cm in diameter) confirmed by miniprobe EUS, and complete resection was achieved in 19 cases. There were no complications except for 8 cases that required endoscopic hemostasis due to bleeding. During the 1-year follow-up, there was no recurrence in one case. The above results demonstrate the accuracy of EUS in determining early GI lesions and the safety and efficacy of EUS-guided EMR in treating certain GI tumors.
4. Other techniques
Dieulafoy’s disease is one of the rare causes of severe GI bleeding, with a reported mortality rate as high as 6l%. With the popularization of endoscopic applications and advances in therapeutic endoscopic techniques, endoscopic local treatment has saved lives rapidly, and the mortality rate of Dieulafoy’s disease has decreased significantly. Because EUS can clear color Doppler to understand the local blood flow, EUS can more easily find the lesion vessels, so that effective hemostasis can be performed.
Ultrasound endoscopy was performed in eight patients with suspected Dieulafoy’s disease, all of whom showed clear and relatively thick vessels, and four patients received sclerotherapy, three of which were performed under ultrasound endoscopic guidance. Subsequently, the technique of EUS-mediated treatment of Dieulafoy disease with collar ligation and hemostatic clips was reported. With the intervention of EUS in the management of Dieu-lafoy disease, the prognosis of patients with Dieulafoy disease will continue to change profoundly.
In conclusion, many promising clinical achievements have been made in interventional ultrasound endoscopy, and it is believed that with the continuous upgrading and development of ultrasound endoscopy and its ancillary equipment, as well as the continuous progress and increasing maturity of ultrasound technology and medical endoscopy technology, new interventional ultrasound endoscopy techniques will continue to be produced and will continue to play a more important role in clinical practice, and the future of interventional ultrasound endoscopy technology is unlimited. The future of interventional ultrasound endoscopy is bright.