Diseases of the Large Bowel

Checklist:

Diseases of the Large Bowel

• Is the patient sufficiently prepared? Check the radiograph of the abdomen before you even think about putting in a rectal tube!

• Is there an ileus, a fistula, or an obstruction of the intestinal lumen, or is the examination scheduled only a few days prior to abdominal surgery? If yes, only water-soluble iodinated contrast medium may be used.

Oh, Bloody Stool

Trudy Herbgarden (55) complains about a change of bowel habits for the last few months. Her primary care physician has done a test of the stool for occult blood, which was positive. Now Mrs. Herbgarden sits in the waiting room and waits for her barium enema. Paul explains the procedure to her once again and makes sure she has understood and followed the rules for the preparation of this particular examination.

J^a, What Is a Perfect Patient Preparation ^^ for the Air Contrast Enema of the feu A j) Large Bowel?

p j^,_^ Two days before the examination the patient should consume nothing but clear liquid foods (clear soups, coffee, tea, clear juices). Salads, wholemeal products, vegetables, fruits, rice, meat, or milk should be avoided in particular. A laxative may also be taken on the day before the examination.

On the eve of the examination (after 10 p.m.) and on the day of the examination nothing may enter the mouth: no smoking, no tooth brushing, no drinking, no eating. Oral medication should be postponed until after the examination if at all possible.

Paul is so fussy in his own interest: if he encounters residual feces in Mrs. Herbgarden's colon, the examination may have to be terminated or it will last much longer because every single fecal particle (sometimes also called fecaloma) must be differentiated from true tumors (Fig. 9.28b) by moving them around with the barium (true tumors are obviously stuck to one place in the wall). After the patient has been positioned comfortably on her side by Mrs. Fairweather, Paul cautiously introduces the rectal tube after having done a careful digital rectal examination. He then inflates a small balloon that sits around the tip of the tube to prevent it from falling out. Paul has the barium suspension flow inside slowly until it reaches the cecum. To facilitate this, he turns Mrs.

a Normal findings a Normal findings

Normal Radiology Large Bowel
Fig. 9.28a This is what a normal double contrast enema of the colon looks like. The bowel is clean and completely distended with air, the mucosa well coated with a barium suspension. A small part of the terminal ileum is also visualized. b The numerous space-occupying lesions (arrows) in this bowel

Herbgarden slowly around her long axis. The suspension is then partially evacuated again; Paul injects a spasmolytic drug (such as glucagon) into her vein and insufflates air cautiously with a balloon pump. The large bowel is expanded in the process.

f Never forget the rectal examination. In glaucoma and i hypertrophy of the prostate, scopolamine derivatives as spasmolytics are contraindicated and glucagon should be used.

The homogeneous and thin barium coating of the bowel wall permits a first-rate evaluation of the mucosa (Fig. 9.28a). Paul unfolds the rectum and sigma by turning the patient under fluoroscopy and shoots radiographs of these colon segments. Subsequently he tilts up the fluoro-scopy table and with it the patient. Air rises and unfolds the splenic and hepatic flexure of the colon in the upper abdomen, Paul has to turn the patient slightly to the left and right to get the best views of these tortuous areas. Standard erect radiographs of the whole colon follow. Now the table is tilted head down to get a good expansion of the cecum, which is also documented on dedicated radiographs. He finishes the examination by producing two large radiographs of the colon with a horizontal x-ray beam—one with the patient positioned on the right, the second with the patient positioned on the left side. These are called left and right decubitus radiographs. It is Paul's ultimate goal to get a double contrast radiograph b Residual stool b Residual stool

Colon Polyps Radiographs
segment were very irritating for the examining physician. It required several radiographs in different patient positions to confirm that they represented retained stool particles. Polyps and also larger malignant lesions can easily be overlooked if the patient preparation is suboptimal.

I Double Contrast Enema of the Large Bowel

I The Case of Trudy Herbgarden

I The Case of Trudy Herbgarden

Barium Enema Positions
Fig. 9.29 Analyze this key radiograph of Mrs. Herbgarden's barium enema. What diseases come to your mind?

of every colon segment in two projections—that is the only way to get a complete examination of the colon without missing a small polyp or cancer. One segment looks a little odd to him (Fig. 9.29).

• What is Your Diagnosis?

Diverticulosis: Diverticulosis is a disease primarily of the sigma and the distal colon, where outpouchings (diverticula) of the bowel wall occur (Fig. 9.30). Inside the diverticula inflammations can develop, termed "diverticulitis" (Fig. 9.31a); patients typically present with fever and left lower abdominal pain. CT can be used to make sure that no abscess formation or perforation of the bowel has occurred if the patients do not readily get better with antibiotic treatment or if there are signs of generalized peritonitis. Recurrent diverticulitis may eventually give rise to stenoses, fistulas, most commonly to the bladder (Fig. 9.31b), and pseudotumors. Imaging cannot not always differentiate them from true malignant processes. It is good practice to obtain a dedicated study of the colon after the acute diverticulitis has resolved to exclude any other serious underlying process. This is also true for patients who get recurrent diverticulitis.

Large-bowel polyps: Polyps are quite frequent in the large bowel (Fig. 9.32a). If they exceed 5 mm in diameter, their chance of malignant transition increases significantly. Their removal is strongly recommended once they reach a size of 10 mm for that reason. Larger tumors may encompass the whole bowel lumen, which eventually leads to a characteristic appearance on a barium enema reminiscent of an "apple core" because of the transition from soft distended colon to rigid narrow cancer back to soft distended colon. Eventually the bowel lumen is obstructed completely and a bowel obstruction develops (see p. 177).

Crohn disease: Crohn disease is an inflammatory bowel disease that causes ulcerations of the bowel wall and eventually results in an image appearance called "cobblestone relief" for obvious reasons (Fig. 9.33). It tends to show a segmental involvement of the gastrointestinal tract ("skip lesions," sparing segments of intestinum in between diseased segments) and spares the rectum. The terminal ileum is frequently involved and fistulas and abscesses occur (see also p. 191).

I Diverticulosis

Diverticulosis Radiograph

Fig. 9.30a Diverticula of the colon are frequent in elderly patients. Often they come in larger numbers as part of a diverticulosis. When imaged sideways they are easily perceived as outpouchings of the bowel wall (arrows). b If imaged head-on, things become a little bit more difficult (arrows) unless

Fig. 9.30a Diverticula of the colon are frequent in elderly patients. Often they come in larger numbers as part of a diverticulosis. When imaged sideways they are easily perceived as outpouchings of the bowel wall (arrows). b If imaged head-on, things become a little bit more difficult (arrows) unless a small contrast-air meniscus is visible, which only occurs in diverticula: every diverticulum needs to be differentiated from a polyp. That is one very good reason for getting two perfect views of every large-bowel segment in a barium enema.

I Complications of Diverticulosis a Diverticulitis b Fistula formation a Diverticulitis

Pictures Bowel Diverticulum And Polps

b Fistula formation

Polyps Diverticula Air Contrast Enema

Fig. 9.31 a The inflammation of a diverticulum may cause regional inflammation of fat around the affected segment of bowel and can even extend into adjacent organs. A stenosis of the bowel lumen results (black arrows) that must be differentiated from a malignant process on the basis of the symptomatology. An intact mucosal appearance may hint at benign underlying etiology. The existence of other diverticula (white arrow) may point the diagnostician in the right direction, but does not entirely exclude a cancer. b In this patient a fistula originating from a diverticulitis has reached the urinary bladder: The air-fluid level (arrows) confirms the finding.

Fig. 9.31 a The inflammation of a diverticulum may cause regional inflammation of fat around the affected segment of bowel and can even extend into adjacent organs. A stenosis of the bowel lumen results (black arrows) that must be differentiated from a malignant process on the basis of the symptomatology. An intact mucosal appearance may hint at benign underlying etiology. The existence of other diverticula (white arrow) may point the diagnostician in the right direction, but does not entirely exclude a cancer. b In this patient a fistula originating from a diverticulitis has reached the urinary bladder: The air-fluid level (arrows) confirms the finding.

I Polyp of the Colon

I Polyp of the Colon

Sessile Polyp Radiology
Fig. 9.32 a This broad-based sessile polyp (arrows) had already are residual stool particles located in the haustrations—or are turned malignant. b Here you see a carcinoma of the cecum these additional polyps? that has caused an incomplete obstruction. Distal to it there

I Crohn

Disease a Manifestations in the colon b Anal fistula a Manifestations in the colon

Fig. 9.33 a The manifestation of Crohn disease in the colon goes along with the formation of the so-called "cobblestone" pattern of the mucosal surface and a stricture of the involved segments. The sigmoid colon is not involved in this case and b Anal fistula

Anal Fistula Radiograph

Fig. 9.33 a The manifestation of Crohn disease in the colon goes along with the formation of the so-called "cobblestone" pattern of the mucosal surface and a stricture of the involved segments. The sigmoid colon is not involved in this case and shows a normal width and mucosal pattern. b Crohn disease has led to a characteristic anal fistula in this patient. A fine catheter (arrow) was introduced into the perianal opening of the fistula.

I Ulcerative Colitis

Image Tortoise Radiology
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Responses

  • benjamin
    Can you see colon polyps on xrays?
    3 years ago

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