DOI: 10.1148/rg.235035701
Filling Defects at CT Colonography: Pseudo- and Diminutive Lesions (The Good), Polyps (The Bad), Flat Lesions, Masses, and Carcinomas (The Ugly)1
Michael Macari, MD,
Edmund J. Bini, MD,
Stacy L. Jacobs, MD,
Nick Lange, BS and
Yvonne W. Lui, MD
1 From the Departments of Radiology (M.M., S.L.J., N.L., Y.W.L.) and Medicine (E.J.B.), New York University Medical Center, 560 First Ave, Suite HW 207, New York, NY 10016; and the Department of Medicine, Veterans Administration Medical Center, New York, NY (E.J.B.). Received January 7, 2003; revision requested March 6 and received April 1; accepted April 4. Address correspondence to M.M. (e-mail: michael.macari@med.nyu.edu).
View larger version (82K):
[in a new window]
|
Figure 1a. Optimal preparation of the colon for virtual colonoscopy. (a) Axial CT image shows multiple colonic segments that are well distended, dry, and without residual fecal material. (b) Endoluminal CT image of the descending colon shows a well-distended colon. Note the interhaustral fold (arrow).
|
|
View larger version (157K):
[in a new window]
|
Figure 1b. Optimal preparation of the colon for virtual colonoscopy. (a) Axial CT image shows multiple colonic segments that are well distended, dry, and without residual fecal material. (b) Endoluminal CT image of the descending colon shows a well-distended colon. Note the interhaustral fold (arrow).
|
|
View larger version (112K):
[in a new window]
|
Figure 2a. Mobility as an indicator of residual fecal material. (a) Supine axial CT image shows a 15-mm homogeneously attenuating filling defect (arrow) on the dorsal aspect of the rectum. (b) Prone axial CT image shows that the filling defect (arrow) is now on the ventral aspect of the rectum, a finding indicative of mobility. In general, mobility indicates residual fecal material.
|
|
View larger version (110K):
[in a new window]
|
Figure 2b. Mobility as an indicator of residual fecal material. (a) Supine axial CT image shows a 15-mm homogeneously attenuating filling defect (arrow) on the dorsal aspect of the rectum. (b) Prone axial CT image shows that the filling defect (arrow) is now on the ventral aspect of the rectum, a finding indicative of mobility. In general, mobility indicates residual fecal material.
|
|
View larger version (130K):
[in a new window]
|
Figure 3a. Pitfall of apparent mobility of a polyp. (a) Supine axial CT image shows a homogeneously attenuating pedunculated filling defect (arrow) in the sigmoid colon. Note that the filling defect is on the ventral, nondependent wall. (b) Prone axial CT image shows that the filling defect (arrow) is now on the dorsal wall. Again, the filling defect is on the nondependent wall. (c) Endoluminal CT image shows the filling defect (arrow), which measures 7 mm. (d) Image from conventional colonoscopy shows that the filling defect is a tubular adenoma (arrow). Apparent mobility of a filling defect, especially in the cecum, transverse colon, and sigmoid colon should be interpreted cautiously, since these areas of the colon may rotate when the patient is turned from supine to prone. If the colon is well prepared and the filling defect is homogeneously attenuating and polypoid, it should be considered a polyp.
|
|
View larger version (127K):
[in a new window]
|
Figure 3b. Pitfall of apparent mobility of a polyp. (a) Supine axial CT image shows a homogeneously attenuating pedunculated filling defect (arrow) in the sigmoid colon. Note that the filling defect is on the ventral, nondependent wall. (b) Prone axial CT image shows that the filling defect (arrow) is now on the dorsal wall. Again, the filling defect is on the nondependent wall. (c) Endoluminal CT image shows the filling defect (arrow), which measures 7 mm. (d) Image from conventional colonoscopy shows that the filling defect is a tubular adenoma (arrow). Apparent mobility of a filling defect, especially in the cecum, transverse colon, and sigmoid colon should be interpreted cautiously, since these areas of the colon may rotate when the patient is turned from supine to prone. If the colon is well prepared and the filling defect is homogeneously attenuating and polypoid, it should be considered a polyp.
|
|
View larger version (175K):
[in a new window]
|
Figure 3c. Pitfall of apparent mobility of a polyp. (a) Supine axial CT image shows a homogeneously attenuating pedunculated filling defect (arrow) in the sigmoid colon. Note that the filling defect is on the ventral, nondependent wall. (b) Prone axial CT image shows that the filling defect (arrow) is now on the dorsal wall. Again, the filling defect is on the nondependent wall. (c) Endoluminal CT image shows the filling defect (arrow), which measures 7 mm. (d) Image from conventional colonoscopy shows that the filling defect is a tubular adenoma (arrow). Apparent mobility of a filling defect, especially in the cecum, transverse colon, and sigmoid colon should be interpreted cautiously, since these areas of the colon may rotate when the patient is turned from supine to prone. If the colon is well prepared and the filling defect is homogeneously attenuating and polypoid, it should be considered a polyp.
|
|
View larger version (136K):
[in a new window]
|
Figure 3d. Pitfall of apparent mobility of a polyp. (a) Supine axial CT image shows a homogeneously attenuating pedunculated filling defect (arrow) in the sigmoid colon. Note that the filling defect is on the ventral, nondependent wall. (b) Prone axial CT image shows that the filling defect (arrow) is now on the dorsal wall. Again, the filling defect is on the nondependent wall. (c) Endoluminal CT image shows the filling defect (arrow), which measures 7 mm. (d) Image from conventional colonoscopy shows that the filling defect is a tubular adenoma (arrow). Apparent mobility of a filling defect, especially in the cecum, transverse colon, and sigmoid colon should be interpreted cautiously, since these areas of the colon may rotate when the patient is turned from supine to prone. If the colon is well prepared and the filling defect is homogeneously attenuating and polypoid, it should be considered a polyp.
|
|
View larger version (93K):
[in a new window]
|
Figure 4a. Eight-millimeter round filling defect in the rectum. (a) Axial CT image shows a well-circumscribed, homogeneously attenuating, round filling defect (arrow) on an interhaustral fold. Arrowhead = rectal catheter. (b) Endoluminal CT image shows the round polypoid morphology of the lesion (arrow). Arrowhead = rectal catheter. (c) Image from conventional colonoscopy shows the identical morphology (arrow). Histologic analysis revealed a tubular adenoma.
|
|
View larger version (176K):
[in a new window]
|
Figure 4b. Eight-millimeter round filling defect in the rectum. (a) Axial CT image shows a well-circumscribed, homogeneously attenuating, round filling defect (arrow) on an interhaustral fold. Arrowhead = rectal catheter. (b) Endoluminal CT image shows the round polypoid morphology of the lesion (arrow). Arrowhead = rectal catheter. (c) Image from conventional colonoscopy shows the identical morphology (arrow). Histologic analysis revealed a tubular adenoma.
|
|
View larger version (131K):
[in a new window]
|
Figure 4c. Eight-millimeter round filling defect in the rectum. (a) Axial CT image shows a well-circumscribed, homogeneously attenuating, round filling defect (arrow) on an interhaustral fold. Arrowhead = rectal catheter. (b) Endoluminal CT image shows the round polypoid morphology of the lesion (arrow). Arrowhead = rectal catheter. (c) Image from conventional colonoscopy shows the identical morphology (arrow). Histologic analysis revealed a tubular adenoma.
|
|
View larger version (176K):
[in a new window]
|
Figure 5. Geometric morphology as an indicator of fecal material. Endoluminal CT image of the sigmoid colon shows a filling defect with angled edges (arrow). This appearance is not consistent with a polyp. Small polyps are round, oval, or lobulated but do not contain geometric edges. Visualization of 3D morphology is facilitated by thin-section multisection CT.
|
|
View larger version (166K):
[in a new window]
|
Figure 6a. Internal heterogeneity as an indicator of fecal material. (a) Endoluminal CT image shows a round well-circumscribed filling defect (arrow) in the cecum. (b) Prone axial CT image shows that the filling defect (arrow) has internal low attenuation, which indicates gas. In small lesions, internal heterogeneity is an indicator of residual fecal material.
|
|
View larger version (92K):
[in a new window]
|
Figure 6b. Internal heterogeneity as an indicator of fecal material. (a) Endoluminal CT image shows a round well-circumscribed filling defect (arrow) in the cecum. (b) Prone axial CT image shows that the filling defect (arrow) has internal low attenuation, which indicates gas. In small lesions, internal heterogeneity is an indicator of residual fecal material.
|
|
View larger version (132K):
[in a new window]
|
Figure 7. Fecal tagging with barium as an aid in differentiation of fecal material from polyps. Axial CT image shows multiple lesions with homogeneous high attenuation (arrow) in the sigmoid colon, an appearance compatible with fecal material.
|
|
View larger version (116K):
[in a new window]
|
Figure 8a. Bulbous fold mimicking a pedunculated polyp. (a) Supine axial CT image shows a pedunculated lesion (arrow) in the sigmoid colon. (b) Coronal CT image shows the linear morphology of the lesion (arrow). (c) Endoluminal CT image shows that the lesion is an interhaustral fold (arrow). Note the small diverticula (arrowheads).
|
|
View larger version (124K):
[in a new window]
|
Figure 8b. Bulbous fold mimicking a pedunculated polyp. (a) Supine axial CT image shows a pedunculated lesion (arrow) in the sigmoid colon. (b) Coronal CT image shows the linear morphology of the lesion (arrow). (c) Endoluminal CT image shows that the lesion is an interhaustral fold (arrow). Note the small diverticula (arrowheads).
|
|
View larger version (157K):
[in a new window]
|
Figure 8c. Bulbous fold mimicking a pedunculated polyp. (a) Supine axial CT image shows a pedunculated lesion (arrow) in the sigmoid colon. (b) Coronal CT image shows the linear morphology of the lesion (arrow). (c) Endoluminal CT image shows that the lesion is an interhaustral fold (arrow). Note the small diverticula (arrowheads).
|
|
View larger version (183K):
[in a new window]
|
Figure 9a. Usefulness of multiple window settings in evaluation of filling defects. (a) Endoluminal CT image shows an 11-mm filling defect of indeterminate origin (arrows) in the cecum. (b) Image from conventional colonoscopy shows the lesion (arrows). (c) Supine axial CT image obtained with a window width of 1,500 HU and window level of -200 HU shows that the lesion (arrow) is indeterminate. (d) Supine axial CT image obtained with a window width of 400 HU and window level of 10 HU shows that the lesion (arrow) is a lipoma. The presence of adipose tissue in a filling defect is confirmation of a lipoma.
|
|
View larger version (117K):
[in a new window]
|
Figure 9b. Usefulness of multiple window settings in evaluation of filling defects. (a) Endoluminal CT image shows an 11-mm filling defect of indeterminate origin (arrows) in the cecum. (b) Image from conventional colonoscopy shows the lesion (arrows). (c) Supine axial CT image obtained with a window width of 1,500 HU and window level of -200 HU shows that the lesion (arrow) is indeterminate. (d) Supine axial CT image obtained with a window width of 400 HU and window level of 10 HU shows that the lesion (arrow) is a lipoma. The presence of adipose tissue in a filling defect is confirmation of a lipoma.
|
|
View larger version (118K):
[in a new window]
|
Figure 9c. Usefulness of multiple window settings in evaluation of filling defects. (a) Endoluminal CT image shows an 11-mm filling defect of indeterminate origin (arrows) in the cecum. (b) Image from conventional colonoscopy shows the lesion (arrows). (c) Supine axial CT image obtained with a window width of 1,500 HU and window level of -200 HU shows that the lesion (arrow) is indeterminate. (d) Supine axial CT image obtained with a window width of 400 HU and window level of 10 HU shows that the lesion (arrow) is a lipoma. The presence of adipose tissue in a filling defect is confirmation of a lipoma.
|
|
View larger version (171K):
[in a new window]
|
Figure 9d. Usefulness of multiple window settings in evaluation of filling defects. (a) Endoluminal CT image shows an 11-mm filling defect of indeterminate origin (arrows) in the cecum. (b) Image from conventional colonoscopy shows the lesion (arrows). (c) Supine axial CT image obtained with a window width of 1,500 HU and window level of -200 HU shows that the lesion (arrow) is indeterminate. (d) Supine axial CT image obtained with a window width of 400 HU and window level of 10 HU shows that the lesion (arrow) is a lipoma. The presence of adipose tissue in a filling defect is confirmation of a lipoma.
|
|
View larger version (204K):
[in a new window]
|
Figure 10a. Ileocecal valve appearing as a prominent filling defect. (a) Endoluminal CT image shows a large filling defect (arrow) in the cecum. (b) Coronal CT image shows a prominent ileocecal valve (arrow). The ileocecal valve may have a number of appearances at endoluminal imaging.
|
|
View larger version (102K):
[in a new window]
|
Figure 10b. Ileocecal valve appearing as a prominent filling defect. (a) Endoluminal CT image shows a large filling defect (arrow) in the cecum. (b) Coronal CT image shows a prominent ileocecal valve (arrow). The ileocecal valve may have a number of appearances at endoluminal imaging.
|
|
View larger version (198K):
[in a new window]
|
Figure 11. Ileocecal valve appearing as a thickened fold. Endoluminal CT image shows a thickened fold with a central opening (large arrow), which represents the ileocecal valve. Note the small polyp in the ascending colon (small arrow).
|
|
View larger version (185K):
[in a new window]
|
Figure 12a. Extrinsic compression appearing as a filling defect in the transverse colon. (a) Endoluminal CT image shows a large smooth filling defect (arrow). (b) Prone axial CT image shows that the filling defect (arrow) is partially extrinsic to the colon. (c) Coronal CT image shows the filling defect as a tubular structure (arrow), which represents a jejunal loop compressing the transverse colon.
|
|
View larger version (88K):
[in a new window]
|
Figure 12b. Extrinsic compression appearing as a filling defect in the transverse colon. (a) Endoluminal CT image shows a large smooth filling defect (arrow). (b) Prone axial CT image shows that the filling defect (arrow) is partially extrinsic to the colon. (c) Coronal CT image shows the filling defect as a tubular structure (arrow), which represents a jejunal loop compressing the transverse colon.
|
|
View larger version (111K):
[in a new window]
|
Figure 12c. Extrinsic compression appearing as a filling defect in the transverse colon. (a) Endoluminal CT image shows a large smooth filling defect (arrow). (b) Prone axial CT image shows that the filling defect (arrow) is partially extrinsic to the colon. (c) Coronal CT image shows the filling defect as a tubular structure (arrow), which represents a jejunal loop compressing the transverse colon.
|
|
View larger version (186K):
[in a new window]
|
Figure 13a. Difference between a polyp and a diverticulum at virtual and conventional colonoscopy. (a) Image from virtual colonoscopy shows a polyp (black arrow) and two small diverticula (white arrows) in the cecum. In general, there is an incomplete border around a polyp, whereas a diverticulum has a complete ring around the orifice. If there is uncertainty at endoluminal imaging, axial images are helpful in differentiating these entities. (b) Image from conventional colonoscopy shows the polyp (black arrow), which measures 7 mm, and the diverticula (white arrows).
|
|
View larger version (140K):
[in a new window]
|
Figure 13b. Difference between a polyp and a diverticulum at virtual and conventional colonoscopy. (a) Image from virtual colonoscopy shows a polyp (black arrow) and two small diverticula (white arrows) in the cecum. In general, there is an incomplete border around a polyp, whereas a diverticulum has a complete ring around the orifice. If there is uncertainty at endoluminal imaging, axial images are helpful in differentiating these entities. (b) Image from conventional colonoscopy shows the polyp (black arrow), which measures 7 mm, and the diverticula (white arrows).
|
|
View larger version (176K):
[in a new window]
|
Figure 14a. Rectal catheters. (a) Endoluminal CT image shows a large-caliber plastic catheter (diameter, 16 mm) (arrow). (b) Endoluminal CT image shows a small-caliber rubber catheter (diameter, 5 mm) (arrow). Both catheters allow good colonic distention, with less discomfort for the patient when the thin catheter is used.
|
|
View larger version (174K):
[in a new window]
|
Figure 14b. Rectal catheters. (a) Endoluminal CT image shows a large-caliber plastic catheter (diameter, 16 mm) (arrow). (b) Endoluminal CT image shows a small-caliber rubber catheter (diameter, 5 mm) (arrow). Both catheters allow good colonic distention, with less discomfort for the patient when the thin catheter is used.
|
|
View larger version (127K):
[in a new window]
|
Figure 15. Diminutive filling defect at colonoscopy. Image from conventional colonoscopy shows a 3-mm raised filling defect (arrows), which could not be visualized even in retrospect with 2D or 3D CT colonography. At histologic analysis, the filling defect was a hyperplastic polyp. Most such small lesions are not seen at CT colonography; however, their clinical significance is minimal.
|
|
View larger version (112K):
[in a new window]
|
Figure 16a. Advantage of performing both supine and prone imaging. (a, b) Prone (a) and supine (b) axial CT images show a small filling defect (arrow) in the descending colon. The filling defect is not mobile. (c) Endoluminal CT image shows that the lesion is polypoid (arrow). At colonoscopy, a 5-mm hyperplastic polyp was found.
|
|
View larger version (114K):
[in a new window]
|
Figure 16b. Advantage of performing both supine and prone imaging. (a, b) Prone (a) and supine (b) axial CT images show a small filling defect (arrow) in the descending colon. The filling defect is not mobile. (c) Endoluminal CT image shows that the lesion is polypoid (arrow). At colonoscopy, a 5-mm hyperplastic polyp was found.
|
|
View larger version (186K):
[in a new window]
|
Figure 16c. Advantage of performing both supine and prone imaging. (a, b) Prone (a) and supine (b) axial CT images show a small filling defect (arrow) in the descending colon. The filling defect is not mobile. (c) Endoluminal CT image shows that the lesion is polypoid (arrow). At colonoscopy, a 5-mm hyperplastic polyp was found.
|
|
View larger version (179K):
[in a new window]
|
Figure 17a. Large pedunculated polyp. (a) Axial CT image shows a pedunculated polyp (arrow) in the sigmoid colon. With the stalk, it measures 37 mm. However, such a polyp should be measured according to the size of the head, which is 13 mm. (b, c) Images from conventional (b) and virtual (c) colonoscopy show the head of the polyp (arrow). Histologic analysis revealed a hyperplastic polyp.
|
|
View larger version (129K):
[in a new window]
|
Figure 17b. Large pedunculated polyp. (a) Axial CT image shows a pedunculated polyp (arrow) in the sigmoid colon. With the stalk, it measures 37 mm. However, such a polyp should be measured according to the size of the head, which is 13 mm. (b, c) Images from conventional (b) and virtual (c) colonoscopy show the head of the polyp (arrow). Histologic analysis revealed a hyperplastic polyp.
|
|
View larger version (170K):
[in a new window]
|
Figure 17c. Large pedunculated polyp. (a) Axial CT image shows a pedunculated polyp (arrow) in the sigmoid colon. With the stalk, it measures 37 mm. However, such a polyp should be measured according to the size of the head, which is 13 mm. (b, c) Images from conventional (b) and virtual (c) colonoscopy show the head of the polyp (arrow). Histologic analysis revealed a hyperplastic polyp.
|
|
View larger version (120K):
[in a new window]
|
Figure 18a. Flat adenoma in the rectum. (a) Image from conventional colonoscopy shows a slightly discolored area (arrows), which is not raised from the background mucosa. Analysis of the biopsy specimen revealed a tubular adenoma. (b) Axial CT image of the same area shows no abnormality (arrow). Even in retrospect, the abnormality could not be seen with 2D or 3D imaging. Truly flat adenomas are nearly impossible to visualize at CT colonography.
|
|
View larger version (96K):
[in a new window]
|
Figure 18b. Flat adenoma in the rectum. (a) Image from conventional colonoscopy shows a slightly discolored area (arrows), which is not raised from the background mucosa. Analysis of the biopsy specimen revealed a tubular adenoma. (b) Axial CT image of the same area shows no abnormality (arrow). Even in retrospect, the abnormality could not be seen with 2D or 3D imaging. Truly flat adenomas are nearly impossible to visualize at CT colonography.
|
|
View larger version (123K):
[in a new window]
|
Figure 19a. Carpetlike filling defect. (a) Prone axial CT image shows fluid (arrow) obscuring the ventral wall of the rectum. (b) Supine axial CT image shows redistribution of the fluid and an irregular carpetlike filling defect (arrow) along the ventral rectal wall. (c) Endoluminal CT image shows the irregular carpetlike morphology of the rectal surface (arrow). Arrowhead = rectal catheter. (d) Image from conventional colonoscopy shows the irregular morphology of the rectal wall (arrow). Histologic analysis revealed a villous adenocarcinoma.
|
|
View larger version (120K):
[in a new window]
|
Figure 19b. Carpetlike filling defect. (a) Prone axial CT image shows fluid (arrow) obscuring the ventral wall of the rectum. (b) Supine axial CT image shows redistribution of the fluid and an irregular carpetlike filling defect (arrow) along the ventral rectal wall. (c) Endoluminal CT image shows the irregular carpetlike morphology of the rectal surface (arrow). Arrowhead = rectal catheter. (d) Image from conventional colonoscopy shows the irregular morphology of the rectal wall (arrow). Histologic analysis revealed a villous adenocarcinoma.
|
|
View larger version (148K):
[in a new window]
|
Figure 19c. Carpetlike filling defect. (a) Prone axial CT image shows fluid (arrow) obscuring the ventral wall of the rectum. (b) Supine axial CT image shows redistribution of the fluid and an irregular carpetlike filling defect (arrow) along the ventral rectal wall. (c) Endoluminal CT image shows the irregular carpetlike morphology of the rectal surface (arrow). Arrowhead = rectal catheter. (d) Image from conventional colonoscopy shows the irregular morphology of the rectal wall (arrow). Histologic analysis revealed a villous adenocarcinoma.
|
|
View larger version (128K):
[in a new window]
|
Figure 19d. Carpetlike filling defect. (a) Prone axial CT image shows fluid (arrow) obscuring the ventral wall of the rectum. (b) Supine axial CT image shows redistribution of the fluid and an irregular carpetlike filling defect (arrow) along the ventral rectal wall. (c) Endoluminal CT image shows the irregular carpetlike morphology of the rectal surface (arrow). Arrowhead = rectal catheter. (d) Image from conventional colonoscopy shows the irregular morphology of the rectal wall (arrow). Histologic analysis revealed a villous adenocarcinoma.
|
|
View larger version (100K):
[in a new window]
|
Figure 20a. Sigmoid carcinoma. (a) Coronal CT image shows a constricting soft-tissue mass (arrow) in the sigmoid colon. (b) Endoluminal CT image shows that the mass is irregular (arrow). Histologic analysis revealed an adenocarcinoma.
|
|
View larger version (200K):
[in a new window]
|
Figure 20b. Sigmoid carcinoma. (a) Coronal CT image shows a constricting soft-tissue mass (arrow) in the sigmoid colon. (b) Endoluminal CT image shows that the mass is irregular (arrow). Histologic analysis revealed an adenocarcinoma.
|
|
View larger version (157K):
[in a new window]
|
Figure 21a. Rectal carcinoma. (a) Sagittal CT image shows an annular constricting soft-tissue mass (arrow) at the rectosigmoid junction. The lesion is easily identified. (b) Endoluminal CT image of the same area shows a normal smooth mucosal pattern with slight irregularity (long arrows). Histologic analysis revealed an adenocarcinoma. Short arrow = rectal catheter.
|
|
View larger version (192K):
[in a new window]
|
Figure 21b. Rectal carcinoma. (a) Sagittal CT image shows an annular constricting soft-tissue mass (arrow) at the rectosigmoid junction. The lesion is easily identified. (b) Endoluminal CT image of the same area shows a normal smooth mucosal pattern with slight irregularity (long arrows). Histologic analysis revealed an adenocarcinoma. Short arrow = rectal catheter.
|
|
View larger version (108K):
[in a new window]
|
Figure 22a. Large rectal mass. (a) Prone axial CT image shows a large mass (arrow) along the ventral aspect of the rectum. (b) Endoluminal CT image shows that the mass (arrow) has a bilobed morphology. Arrowhead = rectal catheter. (c) Image from conventional colonoscopy shows the bilobed morphology of the mass (arrow). The lesion proved to be a large thrombosed hemorrhoid.
|
|
View larger version (152K):
[in a new window]
|
Figure 22b. Large rectal mass. (a) Prone axial CT image shows a large mass (arrow) along the ventral aspect of the rectum. (b) Endoluminal CT image shows that the mass (arrow) has a bilobed morphology. Arrowhead = rectal catheter. (c) Image from conventional colonoscopy shows the bilobed morphology of the mass (arrow). The lesion proved to be a large thrombosed hemorrhoid.
|
|
View larger version (148K):
[in a new window]
|
Figure 22c. Large rectal mass. (a) Prone axial CT image shows a large mass (arrow) along the ventral aspect of the rectum. (b) Endoluminal CT image shows that the mass (arrow) has a bilobed morphology. Arrowhead = rectal catheter. (c) Image from conventional colonoscopy shows the bilobed morphology of the mass (arrow). The lesion proved to be a large thrombosed hemorrhoid.
|
|
View larger version (118K):
[in a new window]
|
Figure 23a. Large colonic mass. Axial (a) and coronal (b) CT images show a 4.5-cm mass (arrow) at the hepatic flexure. The lesion was thought to likely be an adenocarcinoma. At histologic analysis, the lesion proved to be a juvenile polyp.
|
|
View larger version (126K):
[in a new window]
|
Figure 23b. Large colonic mass. Axial (a) and coronal (b) CT images show a 4.5-cm mass (arrow) at the hepatic flexure. The lesion was thought to likely be an adenocarcinoma. At histologic analysis, the lesion proved to be a juvenile polyp.
|
|
Copyright © 2003 by the Radiological Society of North America.
