DOI: 10.1148/rg.276075028
RadioGraphics 2007;27:1693-1703
© RSNA, 2007
Evaluation of Submucosal Lesions of the Large Intestine
Part 2. Nonneoplastic Causes1
Perry J. Pickhardt, MD,
David H. Kim, MD,
Christine O. Menias, MD,
Deepak V. Gopal, MD,
Glen M. Arluk, MD, and
Charles P. Heise, MD
1 From the Department of Radiology (P.J.P., D.H.K.), Section of Gastroenterology and Hepatology (D.V.G.), and Department of Surgery (C.P.H.), University of Wisconsin Medical School, 600 Highland Ave, E3/311 Clinical Science Center, Madison, WI 53792-3252; Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (C.O.M.); and the Department of Gastroenterology, Portsmouth Naval Hospital, Portsmouth, Va (G.M.A.). Recipient of a Certificate of Merit award for an education exhibit at the 2006 RSNA Annual Meeting. Received February 20, 2007; revision requested March 23 and received May 7; accepted May 10. P.J.P. is a consultant with Viatronix, Medicsight, and C.B. Fleet; D.H.K. is a speaker with Viatronix and Medicsight; all remaining authors have no financial relationships to disclose.
Address correspondence to P.J.P. (e-mail: pj.pickhardt{at}hosp.wisc.edu).
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Abstract
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Various nonneoplastic entities may manifest as submucosal abnormalities at colorectal evaluation, and it may be difficult to distinguish between those with an intramural origin and those with an extramural origin on the basis of optical colonoscopy alone. Cross-sectional radiologic imaging, which allows evaluation of the entire bowel wall and the surrounding tissues, plays an important role in the localization and characterization of these abnormalities. However, some superficial submucosal lesions that are initially detected at computed tomographic colonography or barium enema studies may be better characterized with colonoscopy; thus, it is important to recognize the complementary uses of these diagnostic tests. In addition, modalities such as transrectal ultrasonography and magnetic resonance imaging may be useful for the identification and characterization of some abnormalities. For timely and effective management, it is especially important that submucosal neoplasms of the large intestine be accurately distinguished from nonneoplastic entities such as lymphoid polyps, vascular lesions, and cystic lesions, as well as from extracolonic abnormalities (eg, endometriosis, uterine fibroids) and normal extracolonic structures (eg, uterus, vasculature).
© RSNA, 2007
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Introduction
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The term submucosal lesion may be used to describe any masslike protrusion covered by normal overlying mucosa, whether the abnormality is of intramural or extramural origin. 
Optical colonoscopy is of limited use for the characterization of submucosal lesions in the large intestine because it allows only a visual evaluation of the surface of the intestinal lumen. Furthermore, endoscopic biopsy of submucosal lesions is often nondiagnostic and, depending on the cause of the lesion, may even be contraindicated. Additional information about the origin, internal composition, and extent of the lesion can be obtained less invasively with cross-sectional radiologic imaging, which allows an evaluation of the full thickness of the bowel wall and the surrounding tissues. However, it may be difficult to distinguish superficial submucosal soft-tissue lesions from mucosal polyps at radiologic imaging; in such cases, colonoscopy may provide complementary information about abnormalities initially detected at computed tomographic (CT) colonography or a barium enema study. Depending on the specific clinical situation, colonoscopy, CT colonography, transrectal ultrasonography (US), and magnetic resonance (MR) imaging all may play an important role in the evaluation of submucosal lesions.
This article is the second in a two-part review of the radiologic and endoscopic imaging appearances of submucosal lesions, and its particular focus is on nonneoplastic lesions (Table). Emphasis is placed on the complementary use of optical colonoscopy and CT colonography for a comprehensive evaluation of these lesions. Although screening for mucosal polyps and masses is the primary indication for CT colonography (1,2), this modality also may be useful for further evaluation of submucosal abnormalities detected at colonoscopy (3). We use a standard unenhanced CT colonography protocol to evaluate most submucosal abnormalities initially observed at colonoscopy, but the use of intravenous contrast material may be valuable in certain instances. In addition to colonoscopy and CT colonography, transrectal US may be very helpful for evaluating some rectosigmoid lesions, and MR imaging may allow a more comprehensive assessment of broad-based extrinsic or exoenteric processes.
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Nonneoplastic Lesions with an Intramural Origin
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The various nonneoplastic entities that may arise deep to the mucosa within the wall of the large intestine and produce a focal submucosal abnormality are heterogeneous and unrelated. These entities include lymphoid polyps and lymphoid hyperplasia, vascular lesions, cystic lesions, intramural hematoma, and pneumatosis cystoides.
Lymphoid Polyps and Hyperplasia
Benign lymphoid polyps are occasionally seen at endoluminal examination of the large intestine. Most such lesions are small. Very small polyps are sometimes categorized pathologically as mucosal tags with prominent lymphoid aggregates (4). However, some lymphoid polyps may be large enough to simulate a significant pathologic condition, and, rarely, these may become pedunculated (Figs 1, 2) (5). The simultaneous appearance of innumerable small lymphoid polyps is referred to as nodular lymphoid hyperplasia and is more commonly seen in children (Fig 3). Rarely, prominent cases of lymphoid hyperplasia may simulate lymphomatous polyposis.
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Figure 1a. Lymphoid polyp. (a) Endoluminal three-dimensional (3D) CT colonographic image shows a subtle, flat 8-mm lesion (arrowheads) in the low rectum. Note the adjacent rectal catheter. (b) Image from same-day optical colonoscopy shows the lesion before snare cautery. The lesion was diagnosed at histologic evaluation.
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Figure 1b. Lymphoid polyp. (a) Endoluminal three-dimensional (3D) CT colonographic image shows a subtle, flat 8-mm lesion (arrowheads) in the low rectum. Note the adjacent rectal catheter. (b) Image from same-day optical colonoscopy shows the lesion before snare cautery. The lesion was diagnosed at histologic evaluation.
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Figure 2a. Lymphoid polyps. (a) Transverse prone two-dimensional (2D) CT colonographic image shows a large soft-tissue polyp (arrowhead) in the cecum. Three lesions within close proximity, each with a size of 1.5 cm or less, were detected at CT colonography. (b) Optical image from same-day colonoscopy shows the same lesions.
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Figure 2b. Lymphoid polyps. (a) Transverse prone two-dimensional (2D) CT colonographic image shows a large soft-tissue polyp (arrowhead) in the cecum. Three lesions within close proximity, each with a size of 1.5 cm or less, were detected at CT colonography. (b) Optical image from same-day colonoscopy shows the same lesions.
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Figure 3. Nodular lymphoid hyperplasia. Optical colonoscopic image shows multiple tiny polyps adjacent to the appendiceal orifice. Lesions of this size may be difficult to detect reliably at radiologic imaging.
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Vascular Lesions
Nonneoplastic vascular lesions that may produce focal submucosal abnormalities include internal hemorrhoids, rectal varices, and venous malformations. At optical colonoscopy, the observation of the characteristic features of such vascular entities obviates biopsy. Internal hemorrhoids are a common incidental finding; complications include bleeding, thrombosis, and prolapse. An anorectal location and a circumferential or hemicircumferential appearance at CT colonography and barium enema study usually help distinguish an internal hemorrhoid from a mucosal mass, but correlation with findings at physical examination is sometimes helpful (Figs 4, 5). Rectal varices are associated with portal hypertension (Fig 6), whereas hemorrhoids generally are not; findings of cirrhosis and portal hypertension may be apparent at radiologic imaging (Fig 4). Small venous malformations or vascular blebs are commonly seen as an isolated feature and rarely may be indicative of blue rubber bleb nevus syndrome. A characteristic bluish hue at colonoscopy is diagnostic of a venous malformation. At unenhanced CT colonography, nonneoplastic vascular lesions demonstrate soft-tissue attenuation mimicking that of mucosal polyps (Fig 7) (6). In our experience, such lesions often occur in multiples, tend to involve the transverse colon, and almost always are less than 1 cm in size.
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Figure 4a. Internal hemorrhoids. (4a, 4b) Endoluminal 3D (4a) and coronal 2D (4b) CT colonographic images show a lobulated soft-tissue mass surrounding the rectal catheter. Although this is a fairly extreme example, the findings are characteristic of internal hemorrhoids. (4c) Image from same-day optical colonoscopy, which was performed for reasons other than the CT colonographic finding, shows a similar appearance.
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Figure 4b. Internal hemorrhoids. (4a, 4b) Endoluminal 3D (4a) and coronal 2D (4b) CT colonographic images show a lobulated soft-tissue mass surrounding the rectal catheter. Although this is a fairly extreme example, the findings are characteristic of internal hemorrhoids. (4c) Image from same-day optical colonoscopy, which was performed for reasons other than the CT colonographic finding, shows a similar appearance.
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Figure 4c. Internal hemorrhoids. (4a, 4b) Endoluminal 3D (4a) and coronal 2D (4b) CT colonographic images show a lobulated soft-tissue mass surrounding the rectal catheter. Although this is a fairly extreme example, the findings are characteristic of internal hemorrhoids. (4c) Image from same-day optical colonoscopy, which was performed for reasons other than the CT colonographic finding, shows a similar appearance.
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Figure 6a. Rectal varices. (a) Endoluminal 3D CT colonographic image shows a tortuous tubular structure (arrowheads) that extends along a rectal valve, a finding indicative of a small varix. (b) Optical image from colonoscopy in another patient, who had advanced portal hypertension, shows several similar but more extensive features.
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Figure 6b. Rectal varices. (a) Endoluminal 3D CT colonographic image shows a tortuous tubular structure (arrowheads) that extends along a rectal valve, a finding indicative of a small varix. (b) Optical image from colonoscopy in another patient, who had advanced portal hypertension, shows several similar but more extensive features.
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Figure 7a. Venous malformations (vascular blebs). (a, b) Endoluminal 3D (a) and transverse 2D (b) CT colonographic images show a polypoid lesion with soft-tissue attenuation (arrowhead in b). Other subcentimeter-sized lesions (not shown) also were found. (c) Image from optical colonoscopy shows polypoid lesions with a bluish hue (arrowhead), findings characteristic of venous malformations or blebs.
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Figure 7b. Venous malformations (vascular blebs). (a, b) Endoluminal 3D (a) and transverse 2D (b) CT colonographic images show a polypoid lesion with soft-tissue attenuation (arrowhead in b). Other subcentimeter-sized lesions (not shown) also were found. (c) Image from optical colonoscopy shows polypoid lesions with a bluish hue (arrowhead), findings characteristic of venous malformations or blebs.
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Figure 7c. Venous malformations (vascular blebs). (a, b) Endoluminal 3D (a) and transverse 2D (b) CT colonographic images show a polypoid lesion with soft-tissue attenuation (arrowhead in b). Other subcentimeter-sized lesions (not shown) also were found. (c) Image from optical colonoscopy shows polypoid lesions with a bluish hue (arrowhead), findings characteristic of venous malformations or blebs.
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Cystic Lesions
Nonneoplastic cystic lesions that may arise from the colonic or rectal wall include duplication cysts, lymphangiomas, and colitis cystica profunda. Cross-sectional modalities such as MR imaging and transrectal US are capable of demonstrating the cystic nature of these lesions.
Enteric Duplication Cysts.—
These uncommon congenital abnormalities may occur anywhere in the gastrointestinal tract. Duplication cysts are rare in the large intestine and are most often located in the rectum (Fig 8). The associated symptoms depend on the specific location but may include gastrointestinal bleeding, pain, a palpable mass, obstruction, and constipation. Like gastrointestinal stromal tumors, duplication cysts generally have a largely exoenteric location. The demonstration of mural layers in the cyst wall at US is highly suggestive of the diagnosis.
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Figure 8a. Rectal duplication cyst. Coronal T2-weighted (a) and contrast-enhanced T1-weighted gradient-echo (b) MR images show a well-defined cystic lesion (*) that contacts a relatively long segment of the rectum. A rectal duplication cyst was confirmed at surgery.
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Figure 8b. Rectal duplication cyst. Coronal T2-weighted (a) and contrast-enhanced T1-weighted gradient-echo (b) MR images show a well-defined cystic lesion (*) that contacts a relatively long segment of the rectum. A rectal duplication cyst was confirmed at surgery.
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Cystic Lymphangioma.—
This rare benign entity appears as a well-defined cystic submucosal lesion at optical colonoscopy and often is compressible (Fig 9). Internal septa may be apparent at cross-sectional imaging (7).
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Figure 9a. Colonic cystic lymphangioma. (a, b) Endoluminal 3D (a) and transverse 2D (b) CT colonographic images show a lobulated cystic mass in the ascending colon. (c) Optical colonoscopic image shows a tense-appearing bluish submucosal lesion.
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Figure 9b. Colonic cystic lymphangioma. (a, b) Endoluminal 3D (a) and transverse 2D (b) CT colonographic images show a lobulated cystic mass in the ascending colon. (c) Optical colonoscopic image shows a tense-appearing bluish submucosal lesion.
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Figure 9c. Colonic cystic lymphangioma. (a, b) Endoluminal 3D (a) and transverse 2D (b) CT colonographic images show a lobulated cystic mass in the ascending colon. (c) Optical colonoscopic image shows a tense-appearing bluish submucosal lesion.
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Colitis Cystica Profunda.—
This rare and poorly understood condition shares some clinical features with the polypoid variant of solitary rectal ulcer syndrome, which is also poorly understood (8). Colitis cystica profunda is a chronic benign disorder characterized by dilated mucin-filled submucosal rectal cysts (Fig 10). Care must be taken to avoid misdiagnosis resulting from confusion of this condition with other, more common anorectal diseases.
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Figure 10a. Colitis cystica profunda. (a) Lateral projection from barium imaging shows a large, lobulated filling defect from dilated submucosal glands in the low rectum that resembles an internal hemorrhoid. (b) Optical colonoscopic image obtained in another patient shows a smooth, lobulated submucosal abnormality within the rectum.
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Figure 10b. Colitis cystica profunda. (a) Lateral projection from barium imaging shows a large, lobulated filling defect from dilated submucosal glands in the low rectum that resembles an internal hemorrhoid. (b) Optical colonoscopic image obtained in another patient shows a smooth, lobulated submucosal abnormality within the rectum.
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Intramural Hematoma
Colonic intramural hematomas may be iatrogenic (eg, occur as a complication of colonoscopic polypectomy), may be related to other trauma, or may represent an underlying disease process (eg, vasculitis or bleeding diathesis) (Fig 11) (9,10). A localized submucosal hematoma may act as a lead point for intussusception (Fig 12). Surgical intervention may be required in some symptomatic cases of intramural hematoma.
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Figure 11. Intramural hematoma. Contrast-enhanced CT image from a patient with melanoma shows an extensive submucosal hemorrhage that occurred during a biopsy performed at colonoscopy.
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Pneumatosis Cystoides Coli
Cystic or linear gas collections within the bowel wall are collectively termed pneumatosis, and their location may be submucosal or subserosal. The two most important tasks in the evaluation of pneumatosis coli are (a) recognition of the entity and (b) differentiation of the benign form, for which no intervention is indicated, from the potentially life-threatening form (11). Primary pneumatosis cystoides coli is a benign condition that favors the left-sided colon (12). Unlike secondary pneumatosis, which tends to have a more linear appearance, the primary form typically manifests as a marked cluster of air-filled cysts in the colon wall. At endoluminal evaluation with colonoscopy or 3D CT colonography, pneumatosis may simulate polyposis (Fig 13). However, the diagnosis is clear from the internal hypoattenuation, which represents air inside the cysts on 2D CT images, as well as from the internal appearance of the cysts on barium images (Figs 14, 15). The diagnosis also can be confirmed at colonoscopy by eliciting a release of gas with a cyst puncture. Although a linear appearance of secondary pneumatosis at imaging most often is associated with ischemia, this finding is nonspecific because it also may be innocuous. For example, at CT colonographic screening with carbon dioxide distention, linear pneumatosis rarely may be seen as an asymptomatic self-limited entity with no apparent clinical significance (13). Therefore, the correlation of imaging findings with the clinical setting is paramount for deciding the appropriate method of management (Fig 16).
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Figure 13a. Benign asymptomatic pneumatosis cystoides coli. (a) Optical colonoscopic image shows multiple polypoid lesions that were confirmed to represent pneumatosis at subsequent CT (not shown). (b) In another patient, an endoluminal 3D CT colonographic image shows multiple polypoid lesions. The 2D CT colonographic images (not shown) depicted gas inside the lesions.
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Figure 13b. Benign asymptomatic pneumatosis cystoides coli. (a) Optical colonoscopic image shows multiple polypoid lesions that were confirmed to represent pneumatosis at subsequent CT (not shown). (b) In another patient, an endoluminal 3D CT colonographic image shows multiple polypoid lesions. The 2D CT colonographic images (not shown) depicted gas inside the lesions.
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Figure 16a. Colonic pneumatosis with a linear pattern. (a) Contrast-enhanced CT image shows linear areas of gas tracking within the right colonic wall, findings related to necrosis that occurred as a complication of sodium polystyrene sulfonate administration in a patient with renal disease. (b) Transverse 2D image from CT colonographic screening in a healthy patient shows linear areas of pneumatosis throughout the cecum, findings that should not be confused with perforation, which is extremely rare. The patient remained asymptomatic throughout the procedure and afterward; no intervention or treatment was necessary. The marked difference between the clinical relevance of the findings in a and the clinical significance of the similar features depicted in b underscores the need to correlate imaging findings with clinical information.
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Figure 16b. Colonic pneumatosis with a linear pattern. (a) Contrast-enhanced CT image shows linear areas of gas tracking within the right colonic wall, findings related to necrosis that occurred as a complication of sodium polystyrene sulfonate administration in a patient with renal disease. (b) Transverse 2D image from CT colonographic screening in a healthy patient shows linear areas of pneumatosis throughout the cecum, findings that should not be confused with perforation, which is extremely rare. The patient remained asymptomatic throughout the procedure and afterward; no intervention or treatment was necessary. The marked difference between the clinical relevance of the findings in a and the clinical significance of the similar features depicted in b underscores the need to correlate imaging findings with clinical information.
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Nonneoplastic Lesions with an Extramural Origin
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A submucosal impression by an extracolonic entity or invasion by an extracolonic process may be difficult to distinguish from intramural abnormalities at optical colonoscopy and in other strictly luminal examinations. A simple extrinsic impression without mural invasion may be caused by normal adjacent structures or by an abnormal extracolonic lesion. Presacral lesions, which represent a subset of abnormal extrinsic lesions, are discussed separately. Frank invasion of the colonic wall by endometriosis blurs the distinction between extramural and intramural submucosal processes.
Endometriosis
Symptomatic gastrointestinal involvement in endometriosis is relatively uncommon but strongly favors the rectosigmoid region (14). Intestinal involvement is characterized by serosal implantation with a variable degree of intramural extension (Figs 17–19). Deeply penetrating lesions often manifest with hematochezia and may mimic an invasive malignancy at endoluminal examination. Infiltrating peritoneal soft-tissue masses from endometriosis also may mimic carcinomatosis at cross-sectional imaging (Fig 19). A correlation of imaging findings with demographic information and clinical history may be suggestive of the diagnosis, but a previous history of endometriosis often has not been established. Surgery frequently is required both for diagnosis and for therapy if hormonal therapy is unsuccessful.
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Figure 17a. Sigmoid involvement by endometriosis. (a) Optical colonoscopic image in a 41-year-old woman with a family history of colon cancer and no history of endometriosis shows a submucosal mass in the sigmoid colon. (b) Transverse 2D CT colonographic image shows a focal soft-tissue mass (arrowheads). The mass was diagnosed after segmental resection.
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Figure 17b. Sigmoid involvement by endometriosis. (a) Optical colonoscopic image in a 41-year-old woman with a family history of colon cancer and no history of endometriosis shows a submucosal mass in the sigmoid colon. (b) Transverse 2D CT colonographic image shows a focal soft-tissue mass (arrowheads). The mass was diagnosed after segmental resection.
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Figure 18a. Sigmoid involvement by endometriosis. Images from optical colonoscopy (a) and transrectal US (b) in a symptomatic patient show a hypoechoic submucosal mass in the sigmoid colon.
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Figure 18b. Sigmoid involvement by endometriosis. Images from optical colonoscopy (a) and transrectal US (b) in a symptomatic patient show a hypoechoic submucosal mass in the sigmoid colon.
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Extrinsic Impression
Any structure adjacent to the large intestine may produce an impression on the intestinal wall. We have seen a number of referrals for evaluation of possible intramural submucosal lesions identified at optical colonoscopy that proved to be due to extracolonic structures at CT colonography. For this reason and because of the low overall diagnostic success rate of attempted biopsy, optical colonoscopy is of limited value. At CT colonography, 3D endoluminal views can be rapidly correlated with 2D multiplanar reformatted images to identify cases of extrinsic impression. Common sources of extrinsic impression, whether normal or pathologic, include the uterus and adnexa in women, the aorta and common iliac arteries, and adjacent segments of the gastrointestinal tract (Figs 20–22).
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Figure 20a. Extrinsic impressions from extracolonic structures. (20a) Optical colonoscopic image shows a submucosal mass that yielded only colonic mucosa at biopsy. (20b) Transverse 2D CT colonographic image shows that the apparent colonic abnormality is due to an extrinsic impression by a degenerated uterine fibroid (arrowhead).
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Figure 20b. Extrinsic impressions from extracolonic structures. (20a) Optical colonoscopic image shows a submucosal mass that yielded only colonic mucosa at biopsy. (20b) Transverse 2D CT colonographic image shows that the apparent colonic abnormality is due to an extrinsic impression by a degenerated uterine fibroid (arrowhead).
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Figure 21. Endoluminal 3D CT colonographic image shows an apparent large, broad-based cecal lesion, a feature caused by the impression of a normal uterus, as was clearly depicted on the 2D CT colonographic images (not shown). Note the preservation of the displaced but otherwise normal colonic folds.
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Figure 22a. Extrinsic impression from a blood vessel. (a) Endoluminal 3D CT colonographic image shows an elongated abnormality suggestive of a thickened fold or submucosal process. (b) Transverse 2D CT colonographic image shows that the endoluminal feature is produced by the left common iliac artery (arrowhead).
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Figure 22b. Extrinsic impression from a blood vessel. (a) Endoluminal 3D CT colonographic image shows an elongated abnormality suggestive of a thickened fold or submucosal process. (b) Transverse 2D CT colonographic image shows that the endoluminal feature is produced by the left common iliac artery (arrowhead).
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Presacral Lesions
Because the anatomy in the presacral region is relatively confined, any pathologic condition in that region often produces a mass effect on the posterior wall of the rectum. The differential diagnostic possibilities include an array of unrelated entities, such as a tailgut cyst (retrorectal cystic hamartoma), nerve sheath tumor, sarcoma, lymphoproliferative disorder, sacrococcygeal teratoma, anterior sacral meningocele, and an expansile sacral mass (eg, giant cell tumor, chondrosarcoma, aneurysmal bone cyst, or chordoma). Benign tailgut cysts may be the type of presacral lesion most frequently seen in adults (Figs 23, 24) (15).
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Figure 23. Transverse 2D CT colonographic image shows an ovoid cystic lesion in the right presacral space. Focal calcification was seen on 2D images obtained at other levels (not shown). The lesion was subsequently resected and proved to be a retrorectal cystic hamartoma (tailgut cyst).
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Figure 24a. Rectrorectal cystic hamartoma (tailgut cyst). (a) Optical colonoscopic image shows a broad-based bulge posterior to the rectum (arrowheads), a feature that was overlooked at previous endoscopy but found at repeat endoscopy after CT colonography depicted a retrorectal lesion. (b, c) Corresponding transrectal US image (b) and T2-weighted MR image (c) show the complex cystic structure of the lesion (arrowheads in b).
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Figure 24b. Rectrorectal cystic hamartoma (tailgut cyst). (a) Optical colonoscopic image shows a broad-based bulge posterior to the rectum (arrowheads), a feature that was overlooked at previous endoscopy but found at repeat endoscopy after CT colonography depicted a retrorectal lesion. (b, c) Corresponding transrectal US image (b) and T2-weighted MR image (c) show the complex cystic structure of the lesion (arrowheads in b).
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Figure 24c. Rectrorectal cystic hamartoma (tailgut cyst). (a) Optical colonoscopic image shows a broad-based bulge posterior to the rectum (arrowheads), a feature that was overlooked at previous endoscopy but found at repeat endoscopy after CT colonography depicted a retrorectal lesion. (b, c) Corresponding transrectal US image (b) and T2-weighted MR image (c) show the complex cystic structure of the lesion (arrowheads in b).
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Conclusions
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Nonneoplastic lesions represent an important subset of submucosal colorectal abnormalities. In our experience, the combination of optical colonoscopy and CT colonography has proved especially effective for differentiating nonneoplastic entities from neoplasms, and both studies generally can be performed on the same day without the need for additional bowel preparation. Information obtained from cross-sectional imaging of submucosal colorectal lesions is often complementary to that obtained with optical colonoscopy. For the optimal evaluation and appropriate management of submucosal abnormalities, a close collaboration is necessary between radiology, gastroenterology, and colorectal surgery colleagues.
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Footnotes
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Abbreviations: 3D = three-dimensional, 2D = two-dimensional
See also the article by Pickhardt et al on pp 1681–1692.
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References
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Abstract
Introduction
