Virtual Colon Dissection with CT Colonography Compared with Axial Interpretation and Conventional Colonoscopy: Preliminary Results
Hanno Hoppe1,
Cristiana Quattropani2,
Adrian Spreng1,
Jörg Mattich1,
Peter Netzer2 and
Hans-Peter Dinkel1
1 Institute of Diagnostic Radiology, Inselspital, University of Berne,
Freiburgstrasse 10, Berne 3010, Switzerland.
2 Department of Gastroenterology, Inselspital, University of Berne, Berne,
Switzerland.
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Fig. 1A. —Principles of virtual colon dissection. Schematic of virtual
colon dissection shows central colonic path (P) defined semiautomatically.
Virtual camera is oriented perpendicular to this path. Camera displays 3D
panel of inner colonic surface with 90° field of view. To view entire
inner colonic surface, 90° camera field of view is rotated in 45°
increments around path (curved arrows). Subsequent image panels are
rendered by rotation around path.
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Fig. 1B. —Principles of virtual colon dissection. Volume-rendered image
of colon in which central colonic path (white line in colon,
arrows) is defined automatically after manual definition of start and
end points.
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Fig. 1C. —Principles of virtual colon dissection. Generated image panel
is displayed as elongated, flattened view of inner colonic surface. Left upper
corner represents rectum and right lower corner represents cecum. In this
case, 5-mm sessile rectal polyp (arrow) was detected.
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Fig. 2. —Virtual colon dissection of CT colonography data set depicts
poorly distended colon in which parts of inner colonic surface cannot be
rendered with virtual colon dissection. In this case, so-called bridge
(arrows) is inserted connecting previous and following segments but
devoid of diagnostic content. Bridges mainly occur spontaneously in
insufficiently distended colonic segments or in regions with residual
feces.
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Fig. 3A. —54-year-old man with 5-mm sessile polyp (arrow)
extending from haustral fold in sigmoid colon. Conventional colonoscopic image
shows polyp on fold.
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Fig. 3B. —54-year-old man with 5-mm sessile polyp (arrow)
extending from haustral fold in sigmoid colon. Virtual endoscopic image shows
same polyp as in A from similar point of view.
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Fig. 3C. —54-year-old man with 5-mm sessile polyp (arrow)
extending from haustral fold in sigmoid colon. Coronal reformation confirms
round polypoid morphologic structure of lesion.
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Fig. 3D. —54-year-old man with 5-mm sessile polyp (arrow)
extending from haustral fold in sigmoid colon. Virtual colon dissection also
shows this polypoid lesion sitting on haustral fold.
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Fig. 4A. —65-year-old man with 3-mm sessile polyp (arrow) in
ascending colon. Conventional colonoscopic image shows small polyp.
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Fig. 4B. —65-year-old man with 3-mm sessile polyp (arrow) in
ascending colon. Virtual endoscopic image shows same polyp as in A from
similar point of view.
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Fig. 4C. —65-year-old man with 3-mm sessile polyp (arrow) in
ascending colon. On axial image, this small lesion was missed by both
observers, but it could be detected in retrospect.
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Fig. 4D. —65-year-old man with 3-mm sessile polyp (arrow) in
ascending colon. Virtual colon dissection shows small polyp in ascending
colon. Because this lesion could be identified on virtual colon dissection,
one advantage of virtual colon dissection over axial interpretation may be
detection of such smaller lesions.
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Fig. 5A. —62-year-old man with long-stalked adenomatous polyp sitting
on fold in left colonic flexure. Virtual colon dissection shows distortion of
polyp head (white arrow) and stalk (black arrow) due to
elongated, flattened rendering of inner colonic surface.
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Fig. 5B. —62-year-old man with long-stalked adenomatous polyp sitting
on fold in left colonic flexure. CT colonographic endoluminal image shows
pendunculated mass (arrow) on haustral fold.
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Fig. 5C. —62-year-old man with long-stalked adenomatous polyp sitting
on fold in left colonic flexure. Axial image confirms polyp (arrow),
which can be differentiated from haustral fold.
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Copyright © 2004 by the American Roentgen Ray Society.
