Wlk

Figure 5.2. Mineral oil globulosis. (A) Supine film of the abdomen of another patient reveals large masses with cyst wall calcifications in the upper abdomen. (B) CT scan on the same patient shows the thick calcified wall encompassing a mixed attenuation center. (C) Magnified view on one of these lesions demonstrates some of the low density lipid material within the pseudocyst. (Courtesy of S.R. Baker, MD, Newark, NJ)

confusion among radiologists themselves, let alone between radiologists and referring physicians, the term "nonspecific bowel gas pattern" should be banished from the medical lexicon.

Another problem for all imaging modalities is posed when the patient is treated with a nasogastric or long intestinal tube for decompression. Follow-up examinations are often requested to evaluate the results of the treatment. As Baker and Cho have stated, the tube removes the contrast (air and fluid) that we depend upon for our diagnosis [3]. The decreased dilatation gives rise to pain relief [38,39]. The improved radiographic picture is the "beneficial consequence of the treatment of symptoms, not necessarily a manifestation of cure" [3].

The detection of a strangulated small-bowel obstruction via plain film analysis is even more difficult. A gasless abdomen or a severe paucity of bowel gas is a common presentation. However, a gasless abdomen may also be seen with persistent vomiting, with esophageal or gastric outlet obstruction, or even as a variant of normal [3]. One review found that in 18 gasless abdomens, only one third had evidence of strangulation [40]. Another plain film finding is that of distended small-bowel loops surrounded by a rim of fat (mesenteric or serosal in origin) [41]. These loops may be fixed in position on serial films.

Conventional barium studies still play a limited role in the detection and evaluation of small-bowel obstruction. Enteroclysis has certain advantages over the conventional small-bowel series. These are based on bypassing a fluid-filled stomach, not depending on gastric emptying, and stressing the small bowel to its maximal diameter. This latter advantage allows demonstration of minor or relative narrowings that are easily missed on conventional small-bowel series that do not fully distend every loop of small bowel. The intermittent fluoroscopic evaluation utilized in enteroclysis further adds to its utility [42]. However, the authors disagree with a statement that one of the drawbacks to enteroclysis is the need for conscious sedation. One of the authors (BRJ) has performed more than 500 small-bowel enemas without once using conscious sedation.

On conventional small-bowel studies or enteroclysis, adhesions may be noted by acute angulation (Fig. 5.3) or traction on the bowel wall (Fig. 5.4) [43]. When multiple loops are acutely angulated in the same

Figure 5.3. Small-bowel adhesions. Spot film from a double-contrast enteroclysis demonstrates an abrupt change in direction of the small bowel secondary to adhesions in this patient with a prior Whipple's procedure. Also note that the folds have lost their normal transverse orientation.

Figure 5.4. Traction deformity from small-bowel adhesions. Spot film from a double-contrast small-bowel enema shows a traction deformity pulling on and acutely angulating a loop of small bowel deep in the pelvis.

Figure 5.4. Traction deformity from small-bowel adhesions. Spot film from a double-contrast small-bowel enema shows a traction deformity pulling on and acutely angulating a loop of small bowel deep in the pelvis.

general area, a stellate appearance may result (Fig. 5.5). The valvulae conniventes, which are normally perpendicular to the long axis of the small bowel, may become canted or tethered together (Fig. 5.6), thereby indicating an extrinsic process. Pseudosacculations may form when

FIGURE 5.5. Marked small-bowel adhesions.

Coned-down film from an enteroclysis examination reveals the stellate appearance of multiple small-bowel loops as they are acutely angulated to a central point by adhesions.

Figure 5.6. Minimal deformity from small-bowel adhesions. Double-contrast small-bowel enema demonstrates a small area of pleating of the mesenteric border of a loop of ileum in the pelvis (enclosed in brackets). This was thought to represent a "drop" or serosal metastasis from an ovarian primary. At surgery, a small area of scar tissue and adhesion was noted in the area without evidence of recurrent disease.

one wall of the bowel becomes tethered as the opposite side distends. Occasionally, a well-marginated straight or curvilinear crossing defect may be seen, representing a fibrinous band as it crosses the small bowel (Figs. 5.7 and 5.8) [5,42,43]. Rarely, the adhesions may become dense

Bowel Obstruction Enteroclysis
Figure 5.7. Small-bowel adhesion with enterolith formation. Spot film from a small-bowel enema shows a high grade small-bowel obstruction secondary to a crossing adhesion. Just proximal to the adhesion is the round filling defect of an enterolith secondary to this long-standing obstruction.
Figure 5.8. Crossing defect from small-bowel adhesion. Spot film from a single-contrast enteroclysis shows a thick crossing defect from a small-bowel adhesion. The small bowel is dilated downstream from the adhesion because of multiple other adhesions causing a multifocal small bowel obstruction.
Figure 5.9. Small-bowel adhesions mimicking a mass. Conventional small-bowel series reveals marked narrowing and deviation of small bowel loops deep in the pelvis. Recurrent neoplasm was suspected, but at surgery, only marked adhesions were found.

and numerous enough to simulate a mass (Fig. 5.9). When adhesions become obstructive, there may be an abrupt change in caliber of the small bowel. The folds in the prestenotic segments may be normal, or they may become stretched and thinned as the bowel distends proximal to the obstruction. Radiographic depiction of adhesions involving the colon is seen less frequently, probably because the wall of that organ is significantly thicker. Similarly, obstruction is rarely encountered. However, the radiographic appearance is the same (Figs. 5.10 and 5.11).

Figure 5.10. Colonic adhesions. Compression spot film of the hepatic flexure reveals mild deformity of the superior aspect of the colon with pleating and slightly decreased distensibility secondary to pericolonic adhesions.
Adhesions Small Bowel Series
Figure 5.11. Colonic adhesions. Double-contrast enema shows marked distortion of the hepatic flexure with a large pseudodiverticulum. This was secondary to a partial hepatectomy with severe adhesions in the right upper quadrant.

A recent study compared the diagnostic qualities of two different barium suspensions utilized for small-bowel series [44]. Although the authors found significant differences between the two products, they did not study the consequences on diagnostic results. In addition, the barium product that suffered in the comparison was not an up-to-date formulation of a dedicated small-bowel product, while the other one was. At the time of this writing, therefore, no definite reason to prefer one barium product to another can be found.

A study comparing CT and enteroclysis images in diagnosing small-bowel obstruction revealed that the small-bowel enema was far better than CT imaging in detecting obstruction and was only slightly less accurate in determining the cause of the obstruction (Figs. 5.12 and

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