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DOI: 10.1148/rg.266055199
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Three-dimensional Virtual Dissection at CT Colonography: Unraveling the Colon to Search for Lesions1

Alvin C. Silva, MD, Clinton V. Wellnitz, MD and Amy K. Hara, MD

1 From the Department of Diagnostic Radiology, Mayo Clinic, 13400 E Shea Blvd, Scottsdale, AZ 85259. Presented as an education exhibit at the 2004 RSNA Annual Meeting. Received November 10, 2005; revision requested February 6, 2006, and received May 10; accepted June 28. A.K.H. has a licensure agreement with GE Healthcare for the CT colonography software described in this article. All other authors have no financial relationships to disclose.

Figure 1
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  		Figure 1a.  Virtual dissection schema. (a) The virtual dissection software slices the colon open and unfolds it longitudinally by reconstructing the axial CT source image data from the perspective of a virtual camera with an orientation perpendicular to the midline of the colonic tract (T). (b) A 360° view of the inner colonic surface is presented as a flattened 3D panel with a few degrees of overlap at the edges (arrows).

 

Figure 1
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  		Figure 1b.  Virtual dissection schema. (a) The virtual dissection software slices the colon open and unfolds it longitudinally by reconstructing the axial CT source image data from the perspective of a virtual camera with an orientation perpendicular to the midline of the colonic tract (T). (b) A 360° view of the inner colonic surface is presented as a flattened 3D panel with a few degrees of overlap at the edges (arrows).

 

Figure 2
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  		Figure 2a.  Workstation used for the reconstruction and display of virtual dissection images. Two side-by-side monitors allow the simultaneous interactive display of 2D axial, 3D endoluminal, and virtual dissection images. (a) On the first monitor, supine images are displayed in the top row, and prone images are displayed in the bottom row. (b) On the second monitor, a red line on the volume-rendered images (arrowheads at right) denotes the position and length of the colon segments shown on the virtual dissection images (left).

 

Figure 2
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  		Figure 2b.  Workstation used for the reconstruction and display of virtual dissection images. Two side-by-side monitors allow the simultaneous interactive display of 2D axial, 3D endoluminal, and virtual dissection images. (a) On the first monitor, supine images are displayed in the top row, and prone images are displayed in the bottom row. (b) On the second monitor, a red line on the volume-rendered images (arrowheads at right) denotes the position and length of the colon segments shown on the virtual dissection images (left).

 

Figure 3
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  		Figure 3a.  Normal anatomy and common features in a complete CT colonographic examination. (a) Volume-rendered image of the colon, from the rectum to the distal ileum. (b) Virtual dissection image of the same colon shows the rectal tube as an elongated horizontal structure that parallels the midline of the tract (red arrows). The adjacent section outlined in red (Fig. 6) shows the normal appearance of haustral folds in a straight colonic segment. Sections outlined in yellow (Fig. 5, Fig. 7, Fig. 8) and yellow arrows indicate haustral distortions related to the degree of colonic curvature and the relative position of the haustral folds on the virtual dissection image. The section outlined in green (Fig. 9) and the green arrowheads indicate areas of the colon that contain residual fluid. The outlined segments are examined in depth in subsequent figures (Figs 4–9, 16).

 

Figure 3
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  		Figure 3b.  Normal anatomy and common features in a complete CT colonographic examination. (a) Volume-rendered image of the colon, from the rectum to the distal ileum. (b) Virtual dissection image of the same colon shows the rectal tube as an elongated horizontal structure that parallels the midline of the tract (red arrows). The adjacent section outlined in red ((Fig. 6) shows the normal appearance of haustral folds in a straight colonic segment. Sections outlined in yellow (Fig. 5, Fig. 7, Fig. 8) and yellow arrows indicate haustral distortions related to the degree of colonic curvature and the relative position of the haustral folds on the virtual dissection image. The section outlined in green (Fig. 9) and the green arrowheads indicate areas of the colon that contain residual fluid. The outlined segments are examined in depth in subsequent figures (Figs 4–9, 16).

 

Figure 4
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  		Figure 4a.  Rectal valves of Houston. (a) Virtual dissection image shows typical inferior (IV), middle (MV), and superior (SV) valves, which involve the lumen incompletely and have a variable orientation to the midline tract, and a rectal tube tip (arrowheads) that has a characteristic appearance. A pseudoaliasing effect is visible where the middle valve abuts the cut plane of the colon, in the region of overlap. (b) Three-dimensional endoluminal view shows the inferior valve (IV) and rectal tube (T).

 

Figure 4
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  		Figure 4b.  Rectal valves of Houston. (a) Virtual dissection image shows typical inferior (IV), middle (MV), and superior (SV) valves, which involve the lumen incompletely and have a variable orientation to the midline tract, and a rectal tube tip (arrowheads) that has a characteristic appearance. A pseudoaliasing effect is visible where the middle valve abuts the cut plane of the colon, in the region of overlap. (b) Three-dimensional endoluminal view shows the inferior valve (IV) and rectal tube (T).

 

Figure 5
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  		Figure 5a.  Distortions due to the virtual dissection reconstruction process. (a) On the virtual dissection image, the depiction of the haustral fold (arrows) in a curved segment of colon is distorted by focal angulation and pseudoaliasing effects, while the appearance of a typical, vertically oriented fold (arrowheads) in an adjacent straight segment of colon is unaffected. (b, c) Three-dimensional endoluminal view (b) and 2D axial image (c) from the same CT colonographic data set help clarify the nature of the findings on the virtual dissection image by showing normal haustral folds (arrows and arrowheads).

 

Figure 5
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  		Figure 5b.  Distortions due to the virtual dissection reconstruction process. (a) On the virtual dissection image, the depiction of the haustral fold (arrows) in a curved segment of colon is distorted by focal angulation and pseudoaliasing effects, while the appearance of a typical, vertically oriented fold (arrowheads) in an adjacent straight segment of colon is unaffected. (b, c) Three-dimensional endoluminal view (b) and 2D axial image (c) from the same CT colonographic data set help clarify the nature of the findings on the virtual dissection image by showing normal haustral folds (arrows and arrowheads).

 

Figure 5
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  		Figure 5c.  Distortions due to the virtual dissection reconstruction process. (a) On the virtual dissection image, the depiction of the haustral fold (arrows) in a curved segment of colon is distorted by focal angulation and pseudoaliasing effects, while the appearance of a typical, vertically oriented fold (arrowheads) in an adjacent straight segment of colon is unaffected. (b, c) Three-dimensional endoluminal view (b) and 2D axial image (c) from the same CT colonographic data set help clarify the nature of the findings on the virtual dissection image by showing normal haustral folds (arrows and arrowheads).

 

Figure 6
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  		Figure 6a.  Normal haustral folds. Virtual dissection image (a) and 3D endoluminal view (b) show haustral folds with a normal orientation, perpendicular to the long axis of the colon (arrowheads in a). A small amount of residual fluid partially obscures the folds (arrows).

 

Figure 6
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  		Figure 6b.  Normal haustral folds. Virtual dissection image (a) and 3D endoluminal view (b) show haustral folds with a normal orientation, perpendicular to the long axis of the colon (arrowheads in a). A small amount of residual fluid partially obscures the folds (arrows).

 

Figure 7
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  		Figure 7a.  Complex distortion of the appearance of the colon wall and haustral folds. A comparison of the virtual dissection image (a), 3D endoluminal view (b), and volume-rendered image (c) shows artifacts on the virtual dissection image that are caused by complex angulation of the colon (arrows). An apparent polypoid lesion (arrowhead in a and b) represents residual fecal matter, as indicated by its mobility between supine and prone 2D axial views (not shown).

 

Figure 7
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  		Figure 7b.  Complex distortion of the appearance of the colon wall and haustral folds. A comparison of the virtual dissection image (a), 3D endoluminal view (b), and volume-rendered image (c) shows artifacts on the virtual dissection image that are caused by complex angulation of the colon (arrows). An apparent polypoid lesion (arrowhead in a and b) represents residual fecal matter, as indicated by its mobility between supine and prone 2D axial views (not shown).

 

Figure 7
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  		Figure 7c.  Complex distortion of the appearance of the colon wall and haustral folds. A comparison of the virtual dissection image (a), 3D endoluminal view (b), and volume-rendered image (c) shows artifacts on the virtual dissection image that are caused by complex angulation of the colon (arrows). An apparent polypoid lesion (arrowhead in a and b) represents residual fecal matter, as indicated by its mobility between supine and prone 2D axial views (not shown).

 

Figure 8
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  		Figure 8a.  Complex distortion of the appearance of the colon wall and haustral folds. A simultaneous point-to-point correlation of the virtual dissection image (a) with the 3D endoluminal view (b) and volume-rendered image (c) allows an accurate interpretation of a complex fold in an angular segment of the colon (arrows), a feature that mimics a bizarrely shaped polyp or mass on the virtual dissection image.

 

Figure 8
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  		Figure 8b.  Complex distortion of the appearance of the colon wall and haustral folds. A simultaneous point-to-point correlation of the virtual dissection image (a) with the 3D endoluminal view (b) and volume-rendered image (c) allows an accurate interpretation of a complex fold in an angular segment of the colon (arrows), a feature that mimics a bizarrely shaped polyp or mass on the virtual dissection image.

 

Figure 8
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  		Figure 8c.  Complex distortion of the appearance of the colon wall and haustral folds. A simultaneous point-to-point correlation of the virtual dissection image (a) with the 3D endoluminal view (b) and volume-rendered image (c) allows an accurate interpretation of a complex fold in an angular segment of the colon (arrows), a feature that mimics a bizarrely shaped polyp or mass on the virtual dissection image.

 

Figure 9
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  		Figure 9a.  Residual fluid. (a) Virtual dissection image depicts a uniform horizontal band (arrows) indicative of residual fluid that parallels the midline of the tract and obscures portions of the haustral folds. (b) Correlative 2D axial image shows a dependent air-fluid level (arrow).

 

Figure 9
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  		Figure 9b.  Residual fluid. (a) Virtual dissection image depicts a uniform horizontal band (arrows) indicative of residual fluid that parallels the midline of the tract and obscures portions of the haustral folds. (b) Correlative 2D axial image shows a dependent air-fluid level (arrow).

 

Figure 10
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  		Figure 10a.  Polyp in the descending colon. Virtual dissection image (a), 3D endoluminal view (b), and 2D axial image (c) from supine CT colonography, and corresponding colonoscopy image (d), show a lesion (arrow) with a longitudinally distorted appearance on the virtual dissection image and with a broad-based attachment to the colon wall (arrowheads in a and b). It is essential that all longitudinally oriented findings on virtual dissection images be correlated with features on 3D endoluminal and 2D axial views, to differentiate true masses from pseudolesions. The 4-cm polyp was excised and histologically proved to be a sessile tubulovillous adenoma.

 

Figure 10
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  		Figure 10b.  Polyp in the descending colon. Virtual dissection image (a), 3D endoluminal view (b), and 2D axial image (c) from supine CT colonography, and corresponding colonoscopy image (d), show a lesion (arrow) with a longitudinally distorted appearance on the virtual dissection image and with a broad-based attachment to the colon wall (arrowheads in a and b). It is essential that all longitudinally oriented findings on virtual dissection images be correlated with features on 3D endoluminal and 2D axial views, to differentiate true masses from pseudolesions. The 4-cm polyp was excised and histologically proved to be a sessile tubulovillous adenoma.

 

Figure 10
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  		Figure 10c.  Polyp in the descending colon. Virtual dissection image (a), 3D endoluminal view (b), and 2D axial image (c) from supine CT colonography, and corresponding colonoscopy image (d), show a lesion (arrow) with a longitudinally distorted appearance on the virtual dissection image and with a broad-based attachment to the colon wall (arrowheads in a and b). It is essential that all longitudinally oriented findings on virtual dissection images be correlated with features on 3D endoluminal and 2D axial views, to differentiate true masses from pseudolesions. The 4-cm polyp was excised and histologically proved to be a sessile tubulovillous adenoma.

 

Figure 10
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  		Figure 10d.  Polyp in the descending colon. Virtual dissection image (a), 3D endoluminal view (b), and 2D axial image (c) from supine CT colonography, and corresponding colonoscopy image (d), show a lesion (arrow) with a longitudinally distorted appearance on the virtual dissection image and with a broad-based attachment to the colon wall (arrowheads in a and b). It is essential that all longitudinally oriented findings on virtual dissection images be correlated with features on 3D endoluminal and 2D axial views, to differentiate true masses from pseudolesions. The 4-cm polyp was excised and histologically proved to be a sessile tubulovillous adenoma.

 

Figure 11
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  		Figure 11a.  Annular adenocarcinoma in the sigmoid colon. Virtual dissection image (a), 3D endoluminal view (b), 3D volume-rendered image (c), and 2D coronal reformatted image (d) from supine CT colonography, and corresponding colonoscopy image (e), show a mass (arrow) that encircles much of the lumen but spares a small area (arrowhead in a and b). Left-sided adenocarcinomas have this classic apple-core or napkin-ring appearance more often than right-sided adenocarcinomas.

 

Figure 11
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  		Figure 11b.  Annular adenocarcinoma in the sigmoid colon. Virtual dissection image (a), 3D endoluminal view (b), 3D volume-rendered image (c), and 2D coronal reformatted image (d) from supine CT colonography, and corresponding colonoscopy image (e), show a mass (arrow) that encircles much of the lumen but spares a small area (arrowhead in a and b). Left-sided adenocarcinomas have this classic apple-core or napkin-ring appearance more often than right-sided adenocarcinomas.

 

Figure 11
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  		Figure 11c.  Annular adenocarcinoma in the sigmoid colon. Virtual dissection image (a), 3D endoluminal view (b), 3D volume-rendered image (c), and 2D coronal reformatted image (d) from supine CT colonography, and corresponding colonoscopy image (e), show a mass (arrow) that encircles much of the lumen but spares a small area (arrowhead in a and b). Left-sided adenocarcinomas have this classic apple-core or napkin-ring appearance more often than right-sided adenocarcinomas.

 

Figure 11
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  		Figure 11d.  Annular adenocarcinoma in the sigmoid colon. Virtual dissection image (a), 3D endoluminal view (b), 3D volume-rendered image (c), and 2D coronal reformatted image (d) from supine CT colonography, and corresponding colonoscopy image (e), show a mass (arrow) that encircles much of the lumen but spares a small area (arrowhead in a and b). Left-sided adenocarcinomas have this classic apple-core or napkin-ring appearance more often than right-sided adenocarcinomas.

 

Figure 11
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  		Figure 11e.  Annular adenocarcinoma in the sigmoid colon. Virtual dissection image (a), 3D endoluminal view (b), 3D volume-rendered image (c), and 2D coronal reformatted image (d) from supine CT colonography, and corresponding colonoscopy image (e), show a mass (arrow) that encircles much of the lumen but spares a small area (arrowhead in a and b). Left-sided adenocarcinomas have this classic apple-core or napkin-ring appearance more often than right-sided adenocarcinomas.

 

Figure 12
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  		Figure 12a.  Incomplete distention of the colon. Virtual dissection image (a) and 3D volume-rendered image (b) from CT colonography show a featureless gap (arrows) roughly proportional in length to the colon segment that was not distended.

 

Figure 12
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  		Figure 12b.  Incomplete distention of the colon. Virtual dissection image (a) and 3D volume-rendered image (b) from CT colonography show a featureless gap (arrows) roughly proportional in length to the colon segment that was not distended.

 

Figure 13
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  		Figure 13a.  Pedunculated polyp obscured by residual fluid in the ascending colon. (a–d) Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from prone CT colonography, and corresponding colonoscopy image (d), demonstrate a pedunculated polyp (arrow). Residual fluid is visible in a dependent position in a and c (arrowheads). (e) Two-dimensional axial image from supine CT colonography shows only the tip of the polyp (arrow), most of which is submerged in residual fluid (arrowhead). The polyp was likewise obscured by fluid on supine virtual dissection and 3D endoluminal images (not shown). The case illustrates the necessity of reviewing both prone and supine images for accurate CT colonographic interpretation.

 

Figure 13
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  		Figure 13b.  Pedunculated polyp obscured by residual fluid in the ascending colon. (a–d) Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from prone CT colonography, and corresponding colonoscopy image (d), demonstrate a pedunculated polyp (arrow). Residual fluid is visible in a dependent position in a and c (arrowheads). (e) Two-dimensional axial image from supine CT colonography shows only the tip of the polyp (arrow), most of which is submerged in residual fluid (arrowhead). The polyp was likewise obscured by fluid on supine virtual dissection and 3D endoluminal images (not shown). The case illustrates the necessity of reviewing both prone and supine images for accurate CT colonographic interpretation.

 

Figure 13
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  		Figure 13c.  Pedunculated polyp obscured by residual fluid in the ascending colon. (a–d) Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from prone CT colonography, and corresponding colonoscopy image (d), demonstrate a pedunculated polyp (arrow). Residual fluid is visible in a dependent position in a and c (arrowheads). (e) Two-dimensional axial image from supine CT colonography shows only the tip of the polyp (arrow), most of which is submerged in residual fluid (arrowhead). The polyp was likewise obscured by fluid on supine virtual dissection and 3D endoluminal images (not shown). The case illustrates the necessity of reviewing both prone and supine images for accurate CT colonographic interpretation.

 

Figure 13
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  		Figure 13d.  Pedunculated polyp obscured by residual fluid in the ascending colon. (a–d) Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from prone CT colonography, and corresponding colonoscopy image (d), demonstrate a pedunculated polyp (arrow). Residual fluid is visible in a dependent position in a and c (arrowheads). (e) Two-dimensional axial image from supine CT colonography shows only the tip of the polyp (arrow), most of which is submerged in residual fluid (arrowhead). The polyp was likewise obscured by fluid on supine virtual dissection and 3D endoluminal images (not shown). The case illustrates the necessity of reviewing both prone and supine images for accurate CT colonographic interpretation.

 

Figure 13
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  		Figure 13e.  Pedunculated polyp obscured by residual fluid in the ascending colon. (a–d) Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from prone CT colonography, and corresponding colonoscopy image (d), demonstrate a pedunculated polyp (arrow). Residual fluid is visible in a dependent position in a and c (arrowheads). (e) Two-dimensional axial image from supine CT colonography shows only the tip of the polyp (arrow), most of which is submerged in residual fluid (arrowhead). The polyp was likewise obscured by fluid on supine virtual dissection and 3D endoluminal images (not shown). The case illustrates the necessity of reviewing both prone and supine images for accurate CT colonographic interpretation.

 

Figure 14
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  		Figure 14a.  Residual fecal matter in the transverse colon. (a, b) Virtual dissection image (a) and 3D endoluminal view (b) from CT colonography demonstrate a polypoid filling defect (arrow). (c) Axial image from CT colonography shows a heterogeneous defect with a central area of hypoattenuation (arrow) that is characteristic of stool.

 

Figure 14
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  		Figure 14b.  Residual fecal matter in the transverse colon. (a, b) Virtual dissection image (a) and 3D endoluminal view (b) from CT colonography demonstrate a polypoid filling defect (arrow). (c) Axial image from CT colonography shows a heterogeneous defect with a central area of hypoattenuation (arrow) that is characteristic of stool.

 

Figure 14
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  		Figure 14c.  Residual fecal matter in the transverse colon. (a, b) Virtual dissection image (a) and 3D endoluminal view (b) from CT colonography demonstrate a polypoid filling defect (arrow). (c) Axial image from CT colonography shows a heterogeneous defect with a central area of hypoattenuation (arrow) that is characteristic of stool.

 

Figure 15
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  		Figure 15a.  Lipomatous infiltration of the ileocecal valve. Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from CT colonography demonstrate a polypoid filling defect (arrow) that, in c, has attenuation characteristic of fat.

 

Figure 15
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  		Figure 15b.  Lipomatous infiltration of the ileocecal valve. Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from CT colonography demonstrate a polypoid filling defect (arrow) that, in c, has attenuation characteristic of fat.

 

Figure 15
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  		Figure 15c.  Lipomatous infiltration of the ileocecal valve. Virtual dissection image (a), 3D endoluminal image (b), and 2D axial image (c) from CT colonography demonstrate a polypoid filling defect (arrow) that, in c, has attenuation characteristic of fat.

 

Figure 16
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  		Figure 16a.  Ileocecal valve. Virtual dissection image (a), 3D endoluminal view (b), and 2D axial image (c) from CT colonography depict the lumen of the ileocecal valve (arrow). A tiny nearby filling defect (arrowhead in a and b), which demonstrated mobility with changes in patient positioning, represents residual fecal matter.

 

Figure 16
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  		Figure 16b.  Ileocecal valve. Virtual dissection image (a), 3D endoluminal view (b), and 2D axial image (c) from CT colonography depict the lumen of the ileocecal valve (arrow). A tiny nearby filling defect (arrowhead in a and b), which demonstrated mobility with changes in patient positioning, represents residual fecal matter.

 

Figure 16
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  		Figure 16c.  Ileocecal valve. Virtual dissection image (a), 3D endoluminal view (b), and 2D axial image (c) from CT colonography depict the lumen of the ileocecal valve (arrow). A tiny nearby filling defect (arrowhead in a and b), which demonstrated mobility with changes in patient positioning, represents residual fecal matter.

 

Figure 17
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  		Figure 17a.  Appendiceal stump. Virtual dissection image (a), 3D endoluminal view (b), and axial image (c) from CT colonography, and endoscopic image (d), show a polypoid filling defect (arrow) at the cecal base, a finding that represents a pseudolesion from a previous appendectomy. Note the characteristic triangular appearance of the haustral folds at this location.

 

Figure 17
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  		Figure 17b.  Appendiceal stump. Virtual dissection image (a), 3D endoluminal view (b), and axial image (c) from CT colonography, and endoscopic image (d), show a polypoid filling defect (arrow) at the cecal base, a finding that represents a pseudolesion from a previous appendectomy. Note the characteristic triangular appearance of the haustral folds at this location.

 

Figure 17
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  		Figure 17c.  Appendiceal stump. Virtual dissection image (a), 3D endoluminal view (b), and axial image (c) from CT colonography, and endoscopic image (d), show a polypoid filling defect (arrow) at the cecal base, a finding that represents a pseudolesion from a previous appendectomy. Note the characteristic triangular appearance of the haustral folds at this location.

 

Figure 17
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  		Figure 17d.  Appendiceal stump. Virtual dissection image (a), 3D endoluminal view (b), and axial image (c) from CT colonography, and endoscopic image (d), show a polypoid filling defect (arrow) at the cecal base, a finding that represents a pseudolesion from a previous appendectomy. Note the characteristic triangular appearance of the haustral folds at this location.

 

Figure 18
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  		Figure 18a.  Artifacts mimicking polyposis. (a, b) Virtual dissection image (a) and 3D endoluminal view (b) from a supine CT colonographic data set reconstructed with 4-mm collimation at 4-mm intervals show apparent polyps (arrowheads). (c, d) Virtual dissection image (c) and 3D endoluminal view (d) from a prone data set reconstructed with 1-mm collimation at 1-mm intervals show the absence of polyps with the thin-section reconstruction.

 

Figure 18
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  		Figure 18b.  Artifacts mimicking polyposis. (a, b) Virtual dissection image (a) and 3D endoluminal view (b) from a supine CT colonographic data set reconstructed with 4-mm collimation at 4-mm intervals show apparent polyps (arrowheads). (c, d) Virtual dissection image (c) and 3D endoluminal view (d) from a prone data set reconstructed with 1-mm collimation at 1-mm intervals show the absence of polyps with the thin-section reconstruction.

 

Figure 18
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  		Figure 18c.  Artifacts mimicking polyposis. (a, b) Virtual dissection image (a) and 3D endoluminal view (b) from a supine CT colonographic data set reconstructed with 4-mm collimation at 4-mm intervals show apparent polyps (arrowheads). (c, d) Virtual dissection image (c) and 3D endoluminal view (d) from a prone data set reconstructed with 1-mm collimation at 1-mm intervals show the absence of polyps with the thin-section reconstruction.

 

Figure 18
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  		Figure 18d.  Artifacts mimicking polyposis. (a, b) Virtual dissection image (a) and 3D endoluminal view (b) from a supine CT colonographic data set reconstructed with 4-mm collimation at 4-mm intervals show apparent polyps (arrowheads). (c, d) Virtual dissection image (c) and 3D endoluminal view (d) from a prone data set reconstructed with 1-mm collimation at 1-mm intervals show the absence of polyps with the thin-section reconstruction.

 

Figure 19
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  		Figure 19a.  Diverticulosis in the sigmoid colon. Virtual dissection image (a) and 3D endoluminal view (b) from supine CT colonography show diverticula (arrowheads). Frequently found adjacent to the teniae coli, diverticula often are arranged in a linear fashion that is more apparent on virtual dissection images (translucent line in a) than on other CT colonographic views.

 

Figure 19
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  		Figure 19b.  Diverticulosis in the sigmoid colon. Virtual dissection image (a) and 3D endoluminal view (b) from supine CT colonography show diverticula (arrowheads). Frequently found adjacent to the teniae coli, diverticula often are arranged in a linear fashion that is more apparent on virtual dissection images (translucent line in a) than on other CT colonographic views.

 




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