DOI: 10.1148/rg.274065164
Spectrum of Normal and Abnormal CT Appearances of the Ileocecal Valve and Cecum with Endoscopic and Surgical Correlation1
Alvin C. Silva, MD,
Sean D. Beaty, MD,
Amy K. Hara, MD,
Joel G. Fletcher, MD,
Jeff L. Fidler, MD,
Christine O. Menias, MD, and
C. Daniel Johnson, MD
1 From the Department of Diagnostic Radiology, Mayo Clinic, 13400 E Shea Blvd, Scottsdale, AZ 85259 (A.C.S., S.D.B., A.K.H., C.D.J.); Department of Radiology, Mayo Clinic, Rochester, Minn (J.G.F., J.L.F.); and Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (C.O.M.). Recipient of a Certificate of Merit award for an education exhibit at the 2005 RSNA Annual Meeting. Received September 5, 2006; revision requested October 30 and received February 23, 2007; accepted March 1. J.G.F. developed a Continuing Medical Education course for E-Z-EM, is supported in part by Siemens Medical Systems, and has a licensing agreement with GE Healthcare; J.L.F. is a medical advisor for GE Medical Systems; C.D.J. has licensing agreements with GE Medical Systems and E-Z-EM; and A.J.H. has a licensing agreement with GE Medical Systems. All remaining authors have no financial relationships to disclose.
View larger version (80K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1. Drawings illustrate the anatomic structures of the terminal ileum, ICV, cecum, and appendix. m. = muscle. (Reprinted with permission from the Mayo Foundation for Medical Education and Research, Rochester, Minn.)
|
|
View larger version (106K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2a. Labial ICV. Three-dimensional CT colonographic (a) and endoscopic (b) images depict a labial ICV with a flat, slitlike opening (arrows). Note the small amount of fluid flowing from the valve on the endoscopic image.
|
|
View larger version (141K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2b. Labial ICV. Three-dimensional CT colonographic (a) and endoscopic (b) images depict a labial ICV with a flat, slitlike opening (arrows). Note the small amount of fluid flowing from the valve on the endoscopic image.
|
|
View larger version (113K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3a. Papillary ICV. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a papillary type ICV (arrows) with the characteristic dome shape protruding into the lumen of the right colon.
|
|
View larger version (124K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3b. Papillary ICV. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a papillary type ICV (arrows) with the characteristic dome shape protruding into the lumen of the right colon.
|
|
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3c. Papillary ICV. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a papillary type ICV (arrows) with the characteristic dome shape protruding into the lumen of the right colon.
|
|
View larger version (109K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4a. Lipomatous ICV. Endoscopic (a) and axial 2D CT colonographic (b) images depict a prominent lipomatous ICV (arrow). Note the substantial deposit of yellow fat on the endoscopic image and the fat attenuation on the CT colonographic image.
|
|
View larger version (113K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 4b. Lipomatous ICV. Endoscopic (a) and axial 2D CT colonographic (b) images depict a prominent lipomatous ICV (arrow). Note the substantial deposit of yellow fat on the endoscopic image and the fat attenuation on the CT colonographic image.
|
|
View larger version (114K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5a. Polypoid tubular adenoma in a mobile cecum. (a) Three-dimensional CT colonographic image reveals a 1-cm polypoid lesion in the cecum (arrow). (b, c) On corresponding axial 2D supine (b) and prone (c) CT colonographic images (shown in the same orientation), the mass (arrow) appears to move with the change in patient position, a finding that suggests stool. However, closer inspection reveals that the cecum itself rotates with the change in position. Note that the location of the mass remains constant with respect to the terminal ileum and ICV (arrowhead). Biopsy findings showed the mass to be a tubular adenoma.
|
|
View larger version (112K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5b. Polypoid tubular adenoma in a mobile cecum. (a) Three-dimensional CT colonographic image reveals a 1-cm polypoid lesion in the cecum (arrow). (b, c) On corresponding axial 2D supine (b) and prone (c) CT colonographic images (shown in the same orientation), the mass (arrow) appears to move with the change in patient position, a finding that suggests stool. However, closer inspection reveals that the cecum itself rotates with the change in position. Note that the location of the mass remains constant with respect to the terminal ileum and ICV (arrowhead). Biopsy findings showed the mass to be a tubular adenoma.
|
|
View larger version (102K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 5c. Polypoid tubular adenoma in a mobile cecum. (a) Three-dimensional CT colonographic image reveals a 1-cm polypoid lesion in the cecum (arrow). (b, c) On corresponding axial 2D supine (b) and prone (c) CT colonographic images (shown in the same orientation), the mass (arrow) appears to move with the change in patient position, a finding that suggests stool. However, closer inspection reveals that the cecum itself rotates with the change in position. Note that the location of the mass remains constant with respect to the terminal ileum and ICV (arrowhead). Biopsy findings showed the mass to be a tubular adenoma.
|
|
View larger version (108K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6a. Sessile cecal polyp (adenoma). Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a 2.6-cm sessile cecal polyp (arrow) adjacent to the ICV (arrowhead in c). Note that the lobulated surface of the polyp is better depicted at endoscopy than at CT colonography, which is generally the case. However, superficial lobulations on larger polyps can suggest underlying villous components associated with an increased risk of malignancy. The polyp was resected endoscopically and proved to be a tubulovillous adenoma.
|
|
View larger version (122K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6b. Sessile cecal polyp (adenoma). Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a 2.6-cm sessile cecal polyp (arrow) adjacent to the ICV (arrowhead in c). Note that the lobulated surface of the polyp is better depicted at endoscopy than at CT colonography, which is generally the case. However, superficial lobulations on larger polyps can suggest underlying villous components associated with an increased risk of malignancy. The polyp was resected endoscopically and proved to be a tubulovillous adenoma.
|
|
View larger version (111K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 6c. Sessile cecal polyp (adenoma). Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a 2.6-cm sessile cecal polyp (arrow) adjacent to the ICV (arrowhead in c). Note that the lobulated surface of the polyp is better depicted at endoscopy than at CT colonography, which is generally the case. However, superficial lobulations on larger polyps can suggest underlying villous components associated with an increased risk of malignancy. The polyp was resected endoscopically and proved to be a tubulovillous adenoma.
|
|
View larger version (110K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7a. Flat polyp. Three-dimensional (a) and axial 2D supine (b) CT colonographic images demonstrate an 8 x 2-mm flat polyp within the cecum (arrow). Flat polyps may be subtle on 3D images, often requiring verification on the 2D display. Endoscopy showed a 1 x 0.3-cm plaquelike lesion along the base of a cecal fold with minimal elevation.
|
|
View larger version (105K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7b. Flat polyp. Three-dimensional (a) and axial 2D supine (b) CT colonographic images demonstrate an 8 x 2-mm flat polyp within the cecum (arrow). Flat polyps may be subtle on 3D images, often requiring verification on the 2D display. Endoscopy showed a 1 x 0.3-cm plaquelike lesion along the base of a cecal fold with minimal elevation.
|
|
View larger version (96K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8a. Hyperplastic polyp. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a flat 5-mm lesion (arrow) involving a cecal fold. Histologic findings helped identify the polyp as hyperplastic.
|
|
View larger version (128K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8b. Hyperplastic polyp. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a flat 5-mm lesion (arrow) involving a cecal fold. Histologic findings helped identify the polyp as hyperplastic.
|
|
View larger version (100K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 8c. Hyperplastic polyp. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a flat 5-mm lesion (arrow) involving a cecal fold. Histologic findings helped identify the polyp as hyperplastic.
|
|
View larger version (112K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9a. Flat adenocarcinoma. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images reveal a 4-cm partially circumferential flat mass (arrow) involving a cecal fold. The cecum is mobile and medially displaced because of the relatively longer mesentery.
|
|
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9b. Flat adenocarcinoma. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images reveal a 4-cm partially circumferential flat mass (arrow) involving a cecal fold. The cecum is mobile and medially displaced because of the relatively longer mesentery.
|
|
View larger version (106K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 9c. Flat adenocarcinoma. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images reveal a 4-cm partially circumferential flat mass (arrow) involving a cecal fold. The cecum is mobile and medially displaced because of the relatively longer mesentery.
|
|
View larger version (145K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10a. Signet ring cell carcinoma. Three-dimensional (a) and axial 2D (b) CT colonographic images show a 2-cm polypoid mass (arrow) within the cecum. Histopathologic examination showed the mass to be signet ring cell carcinoma.
|
|
View larger version (144K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 10b. Signet ring cell carcinoma. Three-dimensional (a) and axial 2D (b) CT colonographic images show a 2-cm polypoid mass (arrow) within the cecum. Histopathologic examination showed the mass to be signet ring cell carcinoma.
|
|
View larger version (100K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 11a. Lymphoma involving the ICV. Three-dimensional (a) and axial 2D (b) CT colonographic images show mild focal thickening of the distal terminal ileum and ICV (arrows). The subtle wall thickening is best appreciated on the axial 2D image because of better visibility of the wall or valve compared with other adjacent small bowel segments. Note the prominent adjacent mesenteric lymph nodes (arrowhead in b). Biopsy findings demonstrated non-Hodgkin lymphoma.
|
|
View larger version (126K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 11b. Lymphoma involving the ICV. Three-dimensional (a) and axial 2D (b) CT colonographic images show mild focal thickening of the distal terminal ileum and ICV (arrows). The subtle wall thickening is best appreciated on the axial 2D image because of better visibility of the wall or valve compared with other adjacent small bowel segments. Note the prominent adjacent mesenteric lymph nodes (arrowhead in b). Biopsy findings demonstrated non-Hodgkin lymphoma.
|
|
View larger version (136K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 12a. Mucocele of the appendix. Three-dimensional (a) and axial 2D (b) CT colonographic images show a 2.5-cm polypoid lesion (arrow) at the cecal base in the expected location of the appendix. Note the low internal attenuation on the axial image. After surgical excision, the lesion was confirmed to be a mucocele of the appendix.
|
|
View larger version (133K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 12b. Mucocele of the appendix. Three-dimensional (a) and axial 2D (b) CT colonographic images show a 2.5-cm polypoid lesion (arrow) at the cecal base in the expected location of the appendix. Note the low internal attenuation on the axial image. After surgical excision, the lesion was confirmed to be a mucocele of the appendix.
|
|
View larger version (121K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 13a. Appendiceal stump. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a 1.5-cm lesion (arrow) at the base of the cecum. The lesion was thought to represent a polyp at CT colonography, but endoscopy showed it to be an inverted appendiceal stump.
|
|
View larger version (129K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 13b. Appendiceal stump. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a 1.5-cm lesion (arrow) at the base of the cecum. The lesion was thought to represent a polyp at CT colonography, but endoscopy showed it to be an inverted appendiceal stump.
|
|
View larger version (123K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 13c. Appendiceal stump. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images show a 1.5-cm lesion (arrow) at the base of the cecum. The lesion was thought to represent a polyp at CT colonography, but endoscopy showed it to be an inverted appendiceal stump.
|
|
View larger version (136K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 14. Right lower quadrant diverticulitis. Axial contrast material–enhanced CT scan obtained in a patient with clinically suspected acute appendicitis shows thickening of the right colon with pericolonic inflammatory changes (arrowhead) and a hyperenhancing diverticulum (arrow), findings that are consistent with diverticulitis. The appendix was normal.
|
|
View larger version (132K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 15a. Ischemic colitis of the cecum in a 57-year-old patient who had presented to another hospital with abdominal pain and fever, where a cecal mass was identified at abdominal CT. (a) Axial contrast-enhanced CT scan shows irregular cecal wall thickening (arrows). (b) On an image from a subsequent endoscopic study, the wall thickening seen in a appears masslike (arrows). Although the thickened cecal wall was thought to represent an underlying malignancy, histopathologic examination at the time indicated ischemic changes only, and the patient was treated conservatively. (c) Follow-up CT scan obtained 2 weeks after endoscopy demonstrates resolution of the abnormal findings.
|
|
View larger version (146K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 15b. Ischemic colitis of the cecum in a 57-year-old patient who had presented to another hospital with abdominal pain and fever, where a cecal mass was identified at abdominal CT. (a) Axial contrast-enhanced CT scan shows irregular cecal wall thickening (arrows). (b) On an image from a subsequent endoscopic study, the wall thickening seen in a appears masslike (arrows). Although the thickened cecal wall was thought to represent an underlying malignancy, histopathologic examination at the time indicated ischemic changes only, and the patient was treated conservatively. (c) Follow-up CT scan obtained 2 weeks after endoscopy demonstrates resolution of the abnormal findings.
|
|
View larger version (143K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 15c. Ischemic colitis of the cecum in a 57-year-old patient who had presented to another hospital with abdominal pain and fever, where a cecal mass was identified at abdominal CT. (a) Axial contrast-enhanced CT scan shows irregular cecal wall thickening (arrows). (b) On an image from a subsequent endoscopic study, the wall thickening seen in a appears masslike (arrows). Although the thickened cecal wall was thought to represent an underlying malignancy, histopathologic examination at the time indicated ischemic changes only, and the patient was treated conservatively. (c) Follow-up CT scan obtained 2 weeks after endoscopy demonstrates resolution of the abnormal findings.
|
|
View larger version (180K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 16. Colonic infarct with pneumatosis coli in an elderly patient who presented with acute abdominal pain and bleeding of the gastrointestinal tract. Coronal reformatted CT image shows abnormal intramural air (arrows). Frank colonic necrosis was found at surgical exploration.
|
|
View larger version (121K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 17a. Crohn colitis of the cecum mimicking tumor. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images reveal a 2.5-cm lobulated sessile lesion in the base of the cecum (arrow in a and c) with marked edema and ulceration about the cecal base (arrow in b). The lesion was initially thought to be a malignant mass; however, histologic findings demonstrated mild acute colitis compatible with Crohn disease.
|
|
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 17b. Crohn colitis of the cecum mimicking tumor. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images reveal a 2.5-cm lobulated sessile lesion in the base of the cecum (arrow in a and c) with marked edema and ulceration about the cecal base (arrow in b). The lesion was initially thought to be a malignant mass; however, histologic findings demonstrated mild acute colitis compatible with Crohn disease.
|
|
View larger version (142K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 17c. Crohn colitis of the cecum mimicking tumor. Three-dimensional CT colonographic (a), endoscopic (b), and axial 2D CT colonographic (c) images reveal a 2.5-cm lobulated sessile lesion in the base of the cecum (arrow in a and c) with marked edema and ulceration about the cecal base (arrow in b). The lesion was initially thought to be a malignant mass; however, histologic findings demonstrated mild acute colitis compatible with Crohn disease.
|
|
View larger version (143K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 18. Neutropenic colitis. Axial contrast-enhanced CT scan demonstrates marked irregular thickening of a medially oriented cecum (arrows) with associated pericecal inflammatory stranding and fluid. The marked wall thickening with resultant luminal narrowing is known as "cone cecum." The differential diagnosis includes inflammatory bowel disease (Crohn disease and ulcerative colitis), amebiasis, tuberculosis, lymphoma, cecal carcinoma, sequelae of radiation therapy, and metastases.
|
|
View larger version (87K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 19a. Cecal volvulus. Coronal reformatted CT image (a) and axial contrast-enhanced CT scans (b, c) demonstrate a markedly enlarged and dilated air- and fluid-filled cecum (arrow in a and b) extending from the right lower quadrant to the left upper quadrant. Note the abrupt transition between the collapsed, twisted segment of the colon (short arrows in c) and the dilated, obstructed segment (long arrow in c). There is also a subtle whorl of mesenteric vessels (whirl sign) in the right lower quadrant (arrowheads in c) related to torsion of the mesentery caused by the rotated cecum.
|
|
View larger version (144K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 19b. Cecal volvulus. Coronal reformatted CT image (a) and axial contrast-enhanced CT scans (b, c) demonstrate a markedly enlarged and dilated air- and fluid-filled cecum (arrow in a and b) extending from the right lower quadrant to the left upper quadrant. Note the abrupt transition between the collapsed, twisted segment of the colon (short arrows in c) and the dilated, obstructed segment (long arrow in c). There is also a subtle whorl of mesenteric vessels (whirl sign) in the right lower quadrant (arrowheads in c) related to torsion of the mesentery caused by the rotated cecum.
|
|
View larger version (137K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 19c. Cecal volvulus. Coronal reformatted CT image (a) and axial contrast-enhanced CT scans (b, c) demonstrate a markedly enlarged and dilated air- and fluid-filled cecum (arrow in a and b) extending from the right lower quadrant to the left upper quadrant. Note the abrupt transition between the collapsed, twisted segment of the colon (short arrows in c) and the dilated, obstructed segment (long arrow in c). There is also a subtle whorl of mesenteric vessels (whirl sign) in the right lower quadrant (arrowheads in c) related to torsion of the mesentery caused by the rotated cecum.
|
|
View larger version (167K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 20a. Ileocolic intussusception. Axial (a) and coronal (b) reformatted CT images show ileocolic intussusception caused by a large cecal adenocarcinoma (arrow in b), which acts as the lead point in this case. Note the mesenteric fat and vessels (arrow in a) and the terminal ileum (arrowhead in a) associated with the intussuscipiens.
|
|
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 20b. Ileocolic intussusception. Axial (a) and coronal (b) reformatted CT images show ileocolic intussusception caused by a large cecal adenocarcinoma (arrow in b), which acts as the lead point in this case. Note the mesenteric fat and vessels (arrow in a) and the terminal ileum (arrowhead in a) associated with the intussuscipiens.
|
|
Copyright © 2007 by the Radiological Society of North America.
