IBD- Crohn's Disease and Ulcerative Colitis - Essay Example

?Comparison of imaging modalities for IBD- Crohn's Disease and Ulcerative Colitis Inflammatory bowel disease as discussed by Rowe and Shaik (2005) covers a group of disorders in which the intestines become inflamed probably as a result of an immune reaction of the body against its own intestinal tissue. Ulcerative colitis (UC) and Crohn's disease (CD) are two major types of IBD. There are differences between the two, as the name suggests, ulcerative colitis is limited to the colon while Crohn’s disease commonly affects the small intestines although it can involve any part of the gastrointestinal tract from the mouth to the anus. Having symptoms suggesting of IBD need a series of tests for definitive diagnosis of what type of IBD it is and what treatment needs to be implied. Rowe further stated (2011) that multiple studies on mortality in patients with IBD have been conducted from regions throughout the world. The standardized mortality ratio for IBD generally ranges from approximately 1.4 times to 5 times the general population suggesting 95% that the increase in relative risk is real. This implies the importance of early diagnosis and proper treatment to reduce chances of increasing IBD mortality rate. In this pillar comes the importance of diagnostic examinations that this study would like to unveil in terms of pros, cons, sensitivity, specificity, indications and contraindications and finally costs and availability. Endoscopic Endoscopic examination is a mainstay in the diagnosis of IBD. Endoscopic appearance in terms of distribution and shape of lesions helps to differentiate Crohn’s Disease from Ulcerative Colitis in most cases (Nikolaus and Schreiber, 2007). It is an essential tool for diagnosis, management and prognostic evaluation of inflammatory bowel disease. However discomfort, potential risks and costs associated to endoscopic examinations should contribute to the narrowing of indications to those cases in which the result of endoscopy is essential to determine a variation in the management strategy (Daperno et al, 2004, p. 209). The following examinations are the types of endoscopy. Colonoscopy A colonoscopy is an endoscopic procedure used to examine the inside of the colon useful in detecting colon cancer, ulcers, inflammation, and other problems in the colon (Tresca, 2011). Rowe (2011) even stated that colonoscopy is one of the most valuable tools available to the physician for the diagnosis and treatment of IBD. It can help determine the extent and severity of colitis, assist in guiding treatment, and provide tissue to assist in the diagnosis. It can also be used for therapeutic intervention in patients with IBD like stricture dilation in persons with Crohn disease. In addition, intralesional injection of steroids can also be done to help prevent reformation of the stricture (Rowe, 2011). Reaction to medication, bleeding and perforation are some risk associated with colonoscopy. The risk of bleeding is increased in the presence of inflammation, and even mucosal biopsies may require cautery to limit bleeding. The risk of perforation is also increased, particularly in patients taking high doses of steroids long term (Rowe, 2011) Flexible Sigmoidoscopy Rowe (2011) deemed this study useful for a preliminary diagnosis in patients with chronic diarrhoea or rectal bleeding however, diagnosis is restricted due to limited length of the scope (60 cm), it can only help diagnose distal ulcerative colitis. Upper Endoscopy EGD is a common procedure that is used to evaluate a wide variety of symptoms, such as abdominal pain, nausea, vomiting, and painful swallowing. Unlike ulcerative colitis, Crohn's disease can affect the esophagus, stomach, and small bowel. However the scope of view of an EGD is limited, more than 20 feet of small bowel are beyond the reach of an EGD. An enteroscope, a longer EGD, may be used to look further in the small intestine but still more than one-third of the small bowel cannot be reached (Velayo and Mahadevan, 2002) Esophagogastroduodenoscopy (EGD) is used for the evaluation of upper GI tract symptoms, particularly in patients with Crohn’s disease. The diagnosis of Crohn’s disease is occasionally made after gastric or duodenal ulcers fail to heal with acid suppression alone. Patients with IBD who are undergoing endoscopic procedures have higher complication rates than the general population; the informed consent obtained for endoscopic procedures should always mention bleeding and perforation as potential complications (Rowe 2011). Small Bowel Follow Through This procedure is of limited use in patients with Crohn’s disease and is of almost no value in those with ulcerative colitis (Rowe, 2011). SBFT is widely available and still most often used technique to detect small bowel lesions if CD is suspected due to its cheapness and high availability (Nikolaus and Schreiber, 2007, p. 1678). Disadvantages include high exposure to radiation and the need for an experienced radiologist to perform the procedure with credible results. Also sensitivity to detect marginal changes is low in comparison with direct visualization (Nikolaus and Schreiber, 2007, p. 1678). Capsule Enteroscopy For Capsule Enteroscopy a capsule is swallowed after a fasting period of up to 12 h and is propelled through the bowel by peristalsis so that the mucosal surface of the small bowel can be depicted in details (Horsthuis et al, 2007, p 408). This method is most commonly used for finding obscure sources of GI blood loss; the images can find ulcerations associated with Crohn’s disease if upper endoscopy and colonoscopy are unrevealing and the use of capsule enteroscopy for the diagnosis of Crohn’s disease is currently under evaluation (Rowe, 2011). The major risk of this examination in patients with Crohn’s disease is the potential for the camera to become lodged at the point of a stricture, which could require operative intervention for removal (Rowe, 2011). Pitfalls in the use of capsule enteroscopy includes having lesions mimicking normal folds, poor localization of the pathology, capsule retention for patients with asymptomatic structures and rapid and slow transit that affects sensitivity of the method (Medina, 2007, p. 576) Barium Enema This imaging technique was one of the first studies that allowed characterization of the typical findings associated with IBD. Normal barium enema findings virtually exclude active ulcerative colitis, whereas abnormal findings can be diagnostic (Rowe, 2011). Barium can be refluxed into the terminal ileum in many cases, which can assist in the diagnosis of Crohn’s disease. Barium enema is contraindicated in patients with moderate to severe colitis, because it risks perforation or precipitation of a toxic megacolon (Rowe, 2011). Small Bowel Enteroclysis The enteroclysis differs from a small bowel series in that a nasoenteric or oroenteric tube is placed and contrast material is instilled directly into the small intestine. This is usually performed when fine detail of the intestinal mucosa is required or the distal small intestine is not adequately seen on the small bowel series owing to dilution of the contrast agent as it passes through the small bowel (Rowe 2011). Computed Tomography Scanning Computed tomography (CT) scanning of the abdomen and pelvis has limited use in the diagnosis of IBD. Wall thickening on CT scans is nonspecific and may occur from smooth muscle contraction especially in the absence of other extra intestinal inflammatory changes but best for demonstrating intra-abdominal abscesses, mesenteric inflammation, and fistulas (Rowe, 2011). CT scanning is the ideal study to determine if the patient has abscesses, and it can be used to guide percutaneous drainage of these abscesses. Fistulae may also be detected on CT scans (Rowe 2011). According to Horsthius et al (2007, 411) the accuracy of CT has mainly been investigated for small-bowel disease. In suspected CD sensitivity was 83% when compared with SBE. When compared with ileoscopy sensitivity values vary from 80% to 88%. Segmental sensitivity of CT was somewhat lower (71.8%) in a study by Molnar et al (2001) comparing CT with SBE and CS (cited by Horsthius et al, 2007, p.411). Disadvantages of CT include inaccurately visualization of superficial lesions, making CT less suitable as a first-line examination for the suspicion of mild disease (Horsthius et al, 2007, p.411). Ultrasonography Ultrasonography is a non-invasive visualization of the abdominal structures that requires fasting for several hours (Horsthius et al, 2007, p. 408). Due to the limited patient preparation necessary and the non-invasive nature of this examination, US can be considered to be a relatively patient-friendly and straightforward examination (Horsthius et al, 2007, p. 409). Though the procedure requires the availability of a well trained operator, it is very useful in detecting inflamed areas of the small bowel as well as the colon with high diagnostic precision. Even pathologic findings can be seen by ultrasonography such as enlarged lymph nodes, abscess, stenosis and fistulas (Nikolaus and Schreiber, 2007, p. 1678). Advantages of ultrasound are quickness, inexpensiveness and high sensitivity in detecting structures in screening patients for the diagnosis of IBD (Nikolaus and Schreiber, 2007, p. 1678-69). Disadvantages on the other hand denote altered result taking due to obesity and presence of gas and sometimes physiologic structures are hidden like the sigmoid within the pelvis location (Nikolaus and Schreiber, 2007, p. 1679). In addition, abdominal CT examination for IBD relies heavily on an enteral contrast medium (Barnes 2008). Reported sensitivity values of US for the detection of IBD in patients with suspected disease vary from 76% to 92% (Horsthius et al, 2007, p. 409). Furthermore Medina (2011, p. 579) also noted the overall sensitivity of US in detecting IBD as 74% to 93% with specificity rate of 78% to 93% while Nikolaus and Schreiber (2007, p. 1678) cited US’ sensitivity rate at 75%-94% and specificity rate at 67%-100% depending on the skill of the operator. Magnetic Resonance Imaging The advent of new technology paved way for new modalities in the diagnosis of IBD. One of which is the discovery of the MRI. Magnetic resonance imaging is a fairly new technique that has been used since the beginning of the 1980s that uses magnetic and radio waves, meaning that there is no exposure to x-rays or any other damaging forms of radiation (Pillinger, 2011). MRI can differentiate active inflammation from fibrosis and therefore can distinguish between inflammation and fibrostenotic lesions in CD. Though not commonly used due to its high cost, the use of non ionizing radiation makes it safe even for pregnant women that other people go for it as well (Nikolaus and Schreiber, 2007, p. 1678). According to Medina ( 2011, p. 578) this non invasive procedure has a high sensitivity and specificity rate of 84% and 100% respectively in detecting and differentiating inflammatory conditions. In addition Schreyer et al (2005) cited MRI sensitivity and specificity on patient’s basis for the detection of active bowel disease as 91% and 71% respectively. PET Scan Positron Emission Tomography is an advancement that emerged in the early 1990s. An innovative diagnostic imaging tool, PET imaging is used by physicians to examine biochemical changes within a patient. A metabolic imaging tool, PET scans are used to diagnose, stage, and follow-up on treatments by examining a patient’s biochemistry. Diseases usually affect the biochemistry of a patient and these changes can be detected by this procedure. PET scanning is a unique, non-invasive diagnostic imaging tool that produces images detailing the biochemical functioning of an organ or tissue, which are essential in staging a cancer and helping to determine the correct course of treatment (Radiology, n.d.). PET imaging advantages in IBD include its ability to detect disease before changes in the anatomy become apparent making it more effective in diagnosing than other imaging tests. It is able to be used as an alternative to biopsy and other exploratory surgeries to determine how much a disease has spread. Its ability to distinguish between benign and malignant tumours make it a more accurate medical tool that can reduce the number of unnecessary surgeries performed due to incorrect diagnosis and staging data (Radiology, n.d.). Despite the number of advantages that PET imaging contains, it also has a number of disadvantages. PET scan risk is caused by the radioactive component used during this procedure. Although the radioactive compounds used are short lived, the radioactive substance may not be suitable for patients who are pregnant nor breast feeding. Since the radioactive exposure in PET imaging is short lived there is only a limited amount of times a patient can undergo this procedure plus the fact the PET scans are expensive with an average cost ranging between $900 and $1400 the reason why they are not offered in the majority of medical centres in the world making it a difficult treatment to receive (Radiology, n.d.). The sensitivity of the PET scanning was 98%, specificity 83%, positive predictive value 93% and negative predictive value 95% (Mernagh and Somers, 1999) Confocal Laser Endomicroscopy Confocal laser endomicroscopy (CLE) as discussed by Othman and Wallace (2011) is a novel imaging technology which utilizes focal laser illumination to scan one focal plane in the selected imaged lesion. This allows for a microscopic view of the surface epithelium creating a “virtual biopsy” of the area of interest. To obtain a high contrast image, CLE requires contrast injection such as fluorescein. The contrast material diffuses through the capillaries and stains the extracellular matrix of the surface epithelium. The difference in contrast allows analysis of the surface mucosa by the examiner and aids in differentiating normal mucosa from neoplastic tissue. An evaluation of 21 patients showed that Confocal laser endomicrsocopy had a sensitivity of 89% and specificity of 100% to identify intramucosal bacteria (Moussata et al, 2010) Researchers have been exploring the clinical applications of this technique in various luminal disorders. Differentiating between hyperplastic, adenomatous, and neoplastic colonic tissue was one of the initial applications of the technique. Other emerging applications include screening for neoplasia in Barrett esophagus, early gastric cancer, and ulcerative colitis surveillance (Othman and Wallace, 2011). Though CLE is examiner dependent the availability of the result as seen by the examiner is deemed an advantage (Nicholls, 2011). Radiologic imaging in inflammatory bowel disease is always complimentary to the clinical assessment of the patient and other investigations. Diagnostic imaging examinations evolved from the constant want of man in highly diagnosing diseases to aid in the proper treatment. CT and MRI are important addition in the diagnosis and management of patients with chronic intestinal inflammation that is superior to the conventional modalities in some cases. The use of the type of imaging depends on the assessment of the patient and can always vary depending on the discretion of the physician as to what type of view is wanted out of the contemplated procedure. Therefore there is no superior imaging modality that can presently be recommended. The choice of the imaging modality always depends on the availability of the resources and the skill of the radiologist as well as the clinical circumstances and suspected disease-associated complications (Schreyer et al, 2004, p. 51). Advancements and future study will be made to enhance further the advantages people gain from technologies and to prove the effectiveness and safety of these procedures. The future of diagnostic imaging looks to further the trend of finding the problem in a patient early, before any insurmountable damage has been done. Future imaging looks to observe patients at the molecular level, by looking at specific cells or proteins it aims at defining how things function when it comes down to the molecular level (Jordan, 2011). Though new forms of imaging would act as an alternative pathway and supplement the current forms of imaging the idea that man would be replaced by computers in regards to imaging is not all possible.  Computers may be able to pick up some of the abnormalities seen in the images but only human intuition can truly identify problematic abnormalities and interpret visual abnormalities into recognition of disease processes (Jordan, 2011). 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