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Imaging in IBD
Published in Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams, Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
Mucosal healing in UC has been associated with a lower risk of colectomy, irrespective of the choice of medical therapy. According to the IBSEN cohort, patients from the pre-biological era with mucosal healing at one year had a lower risk of colectomy at five years (p = 0.02).21 Patients achieving mucosal healing on infliximab treatment by week 8 in the ACT 1 and 2 trials had a lower risk of colectomy at one year.22 Furthermore, mucosal healing was associated with a lower risk of hospitalisation, reduced subsequent immunosuppressive use and a lower risk of colitis related neoplasia.23,24 On the contrary, severe endoscopic lesions were associated with failure to respond to intravenous steroid treatment and cyclosporine rescue.25,26 Therefore, the target of treatment in UC includes clinical and patient-reported remission, as well as endoscopic remission, defined as a Mayo endoscopic subscore of 0–1, as set by the recent STRIDE initiative.27 Mucosal healing is routinely assessed with white light endoscopy. However, experimental evidence indicates that mucosal abnormalities at a cellular level detected by advanced endoscopic imaging techniques, such as magnifying chromoendoscopy or confocal laser endomicroscopy, assess intestinal barrier function and may predict relapse in UC.28–30
Gastrointestinal Endoscopy
Published in Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie, Bailey & Love's Short Practice of Surgery, 2018
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie
Narrow band imaging (NBI) relies on an optical filter technology that radically improves the visibility of capillaries, veins and other subtle tissue structures by optimising the absorbance and scattering characteristics of light. NBI uses two discrete bands of light: one blue at 415 nm and one green at 540 nm. Narrow band blue light displays superficial capillary networks, whereas green light displays subepithelial vessels; when combined they offer an extremely high contrast image of the tissue surface. Autofluorescence images can also be used to increase lesion discrimination. Finally, high-resolution magnifying endoscopy may be used alone or in combination with one of the above techniques to achieve near-cellular definition of the mucosa (Figure 15.20), and is of particular use in neoplasia surveillance. New directions for the future include the increased use of confocal endomicroscopy to achieve histological images at the time of the endoscopic procedure.
Oesophageal cancer
Published in Anju Sahdev, Sarah J. Vinnicombe, Husband & Reznek's Imaging in Oncology, 2020
Nyree Griffin, Jason Dunn, Lee Alexander Grant
Endoscopic screening for Barrett's oesophagus is not currently recommended. However, screening can be considered in patients with long-standing GERD symptoms (i.e. >5 years) and multiple risk factors (age ≥50 years, white race, male sex, obesity, or first-degree relative with Barrett's oesophagus or oesophageal adenocarcinoma). Techniques for non-endoscopic screening (e.g. cytosponge, saliva test) show promise, but further research is required before routine use is recommended (39). Endoscopic surveillance for dysplasia/T1 disease continues to be the gold standard for management of patients with Barrett's oesophagus. In the UK, the interval varies, with a 3–5 year follow-up recommended if the Barrett's segment is <3 cm, and a 2–3 year follow-up if ≥3 cm. The Seattle protocol of random 4 quadrant biopsies every 2 cm, along with targeted biopsies of suspicious lesions, is the benchmark for dysplasia detection and remains the gold standard. It has been shown that the risk of progression to dysplasia increases as the length of the Barrett's segment increases (40). Quality of surveillance is, however, variable. Non-adherence has been reported as high as 50% in a US community setting, and this was associated with significantly decreased dysplasia detection rate (DDR) (41). There is also emerging evidence that the endoscopy withdrawal time correlates with the quality of the surveillance endoscopy (42). Studies using enhanced imaging techniques such as Narrow Band Imaging (NBI, Olympus, Japan), Trimodal imaging, confocal laser endomicroscopy (CLE), and chromoendoscopy have all shown promise in improving dysplasia detection and reducing the number of biopsies taken, though these studies have limited application as they were performed at high-volume centres by endoscopists skilled in endotherapy (43). Advanced techniques may be more advantageous in patients where the intention is a target biopsy, for example in those with previous low-grade or indefinite dysplasia or very long segment Barret's (i.e. ≥10 cm). In these situations, acetic acid is used in chromoendoscopy rather than Lugol's iodine, with suspicious areas seen as areas of loss of aceto-whitening sign (LAWS) (44).
Medical thoracoscopy in the diagnosis of pleural disease: a guide for the clinician
Published in Expert Review of Respiratory Medicine, 2020
Faisal Shaikh, Robert J. Lentz, David Feller-Kopman, Fabien Maldonado
Endomicroscopy is an exciting new application in various endoscopic procedures including MT. Following IV administration of fluorescein, dye emissions allow for in vivo visualization of pleural cells (Cellvizio, Mauna Kea Technologies, Paris, France). The Alveoflex confocal laser endomicroscopy probe (pCLE) is used to provide biopsy guidance with microscopic accuracy. Bonhomme et al. first reported the use of pCLE in thoracoscopy in 2019 in a series of 3 patients [157]. This was followed by an ex-vivo analysis by Zirlik et al. demonstrating an 87% sensitivity and 99% specificity for malignant pleural effusion with pCLE [158]. There are some data to suggest that in cases of early MPM, neoplastic involvement is limited to the submesothelial level without any apparent abnormalities on macroscopic inspection [159]. If indeed pCLE could reliably detect such lesions, an earlier diagnosis of MPM and may lead to significant improvements in survival. As with the other techniques mentioned above, more data is needed to gauge the clinical benefit of this promising technique.
Advances in endoscopy for colorectal polyp detection and classification
Published in Baylor University Medical Center Proceedings, 2020
Vijeta Pamudurthy, Nayna Lodhia, Vani J. A. Konda
Confocal laser endomicroscopy is based on tissue illumination with a low-power laser allowing micron-level spatial resolution with 1000× magnification. As shown in Figure 6, this may lead to immediate detection of CRC and premalignant lesions. Confocal laser endomicroscopy may also assist in the differentiation of neoplasms from nonneoplasms, advanced adenomas from nonadvanced adenomas, and adenomatous from nonadenomatous colorectal polyps while predicting histopathology with high sensitivity and accuracy.40 In a meta-analysis of 15 studies, Su et al concluded that confocal laser endomicroscopy had high sensitivity (94%, 95% CI 88% to 97%) and specificity (95%, 95% CI 89% to 97%) for discriminating between colorectal neoplasms and nonneoplasms, which was comparable to colonoscopic histopathology.41 However, it is a time-consuming, highly examiner-dependent technique and has a steep learning curve.
Advancements in the clinical management of upper tract urothelial carcinoma
Published in Expert Review of Anticancer Therapy, 2019
Jacob Taylor, Xiaosong Meng, Rashed Ghandour, Vitaly Margulis
Furthermore, biopsy tumor grade has been shown to be predictive of final stage at time of RNU [34] and overall survival [35], however, the challenges of small endoscopic instruments and insufficient tissue samples [36] often amount to 25% of samples returning non-diagnostic on pathology reports [37]. There have been advances in endoscopic instruments to help combat this difficulty such as BigOpsy®, a 6F forcep double the size of traditional biopsy instruments, which increased diagnostic accuracy of biopsies by 10% in a small biopsy cohort [38]. A novel flexible cryoprobe (Erb Elektromedizin GmbH) that cools tissue allowing for improved targeted biopsy retrieval was recently found to provide larger tissue samples than BigOpsy® in a preclinical study and may add to endoscopic technology in the future [39]. Despite improved tissue sampling, the high rate of grade reassignment from initial biopsy to final pathology with almost 50% of cases being upgraded from noninvasive to invasive disease is concerning [36,40]. Endoscopic grade assessment with fluorescent confocal laser endomicroscopy may decrease the final pathology grade discrepancy and provide improved intra-operative risk stratification allowing for immediate treatment [41]. However, this technology continues to be refined, needs validation, and is far from standard of care. While these new technologies are exciting and have the potential to serve an important role in the diagnostic armamentarium, continued advancements and improvements in technique are still needed.