Virtual colonoscopy and colorectal cancer screening

Chaoui, A.; Blake, Michael A.; Barish, Matthew A.; Fenlon, Helen M.

doi:10.1007/s002610000012

Cited by 26 publications

(20 citation statements)

References 13 publications

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“…CTC was first realized in the 1990s following the rapid progress in computed tomography (CT) and in digital computing [3]- [5]. CTC is a minimally invasive method that consists of CT imaging the whole abdomen and pelvis after cleansing and air insufflation of the colon.…”

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confidence: 99%

Edge displacement field-based classification for improved detection of polyps in CT colonography

Açar

Beaulieu

Gokturk

et al. 2002

IEEE Trans. Med. Imaging

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Abstract-Colorectal cancer can easily be prevented provided that the precursors to tumors, small colonic polyps, are detected and removed. Currently, the only definitive examination of the colon is fiber-optic colonoscopy, which is invasive and expensive. Computed tomographic colonography (CTC) is potentially a less costly and less invasive alternative to FOC. It would be desirable to have computer-aided detection (CAD) algorithms to examine the large amount of data CTC provides. Most current CAD algorithms have high false positive rates at the required sensitivity levels. We developed and evaluated a postprocessing algorithm to decrease the false positive rate of such a CAD method without sacrificing sensitivity. Our method attempts to model the way a radiologist recognizes a polyp while scrolling a cross-sectional plane through three-dimensional computed tomography data by classification of the changes in the location of the edges in the two-dimensional plane. We performed a tenfold cross-validation study to assess its performance using sensitivity/specificity analysis on data from 48 patients. The mean specificity over all experiments increased from 0.19 (0.35) to 0.47 (0.56) for a sensitivity of 1.00 (0.95).Index Terms-Computed tomographic colonography (CTC), computer-aided diagnosis, edge displacement fields (EDFs), fiber-optic colonoscopy (FOC).

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mentioning

confidence: 99%

Edge displacement field-based classification for improved detection of polyps in CT colonography

Açar

Beaulieu

Gokturk

et al. 2002

IEEE Trans. Med. Imaging

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“…Thanks to advances in computer technology, threedimensional (3D) renderings of the internal surface of hollow viscera can be generated and numerous clinically useful applications have been proposed, especially for colon imaging [1,2,3,4,5]. The biliary tree seems not to be a preferential area for virtual endoscopy, merely because of its relatively small lumen diameter.…”

Section: Introductionmentioning

confidence: 99%

Development of contrast-enhanced virtual MR cholangioscopy: a feasibility study

et al. 2002

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The purpose of this study was to examine the feasibility of contrast-enhanced virtual MR cholangioscopy (CE VMRC). Intraluminal views of the extrahepatic biliary tree were generated in ten patients undergoing abdominal MRI post mangafodipir trisodium administration employing coronal 2.5-mm 3D fast low-angle shot (FLASH) images (TR 6.8 ms, TE 2.3 ms, matrix 195 x 512) with fat saturation and a commercially available software. Contrast-enhanced VMRC was compared with single-shot turbo spin-echo T2-weighted MR cholangiography (T2 MRC) in terms of ductal visualization and artifact presence, utilizing a five-point grading scale. Four anatomic segments were evaluated: the intra- and extra-pancreatic segment of the common bile duct (CBD), and the cystic duct and the area of hepatic duct bifurcation. Both CE VMRC and T2 MRC depicted 38 of 40 segments. There were no significant differences between CE VMRC and T2 MRC in ranking ductal segments visualization ( p=0.27). The high contrast between intraluminal fluid and extraluminal tissues facilitated the generation of endoscopic views. Contrast-enhanced virtual MR cholangioscopy is a feasible technique providing endoscopic views of the CBD. Initial results show correlation of CE VMRC with projectional MR cholangiography.

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“…Although comparisons have been made between VC, colonoscopy and double-contrast barium enema (DCBE) in defined populations, there is as yet no randomized data assessing these techniques in undefined or screened populations with relatively low risk for neoplastic disease [9,10]. What is clear is that the new technology has the theoretical advantage of visualization of the colon proximal to strictured lesions which would be unlikely to admit a colonoscope [11,12].…”

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confidence: 97%

Pneumocolography and virtual colonoscopy: its clinical place and development

Zbar

Beer-Gabel

2001

Techniques in Coloproctology

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Given the increasing strain on colonoscopy services, newer techniques designed to accurately diagnose colorectal cancer or significant colorectal adenomatous polyps should impact substantially on health care costs. These relatively noninvasive techniques, notably magnetic resonance imaging (MRI) and computed tomography (CT) colonography, are likely to be more accurate in displaying the entire colon given the variable rates of total colonoscopy achieved outside of major endoscopic centers. Moreover, although these newer diagnostic strategies still require good quality bowel preparation and smooth muscle relaxation, they are likely to be better tolerated by elderly or frail patients who are unable either to retain barium or undergo colonoscopic examination [1].There are a range of CT-based colonic imaging techniques available. Spiral (helical) CT pneumocolography was introduced by Amin et al.[2] who employed dynamic scanning with intravenous contrast-enhanced thin helical sectioning of the colon without any off-line image post-processing. The Mayo Clinic group led by Hara used CT colography with multiformatted two-dimensional CT images combined with depth-shaded volume rendering for an improved assessment of colorectal polyps [3,4]. Virtual colonoscopy (VC) was a term first used by Vining et al. [5] in 1994, whereby helical CT scanning was combined with advanced post-procedural image manipulation using perspective volume rendering algorithms to create a reconstructed view for hollow viscus tracking of the colon. More recently, endoluminal contrast-enhanced MR reconstructed colonography has been developed for similar purposes [6,7].The advantages of such technology lie in the assessment of the local pathology encountered, defining the presence of significant pericolic lymphadenopathy and in the demonstration of extra-colonic pathology, most notably hepatic metastatic disease. Spiral CT techniques have less motion artifacts, provide better tumor registration, optimal vascular opacification and hepatic parenchymal enhancement. These techniques have been validated in in vitro studies and in cases with proven colonic cancer and polyp disease (providAbstract Colonoscopy is an invasive technique, frequently incomplete and often poorly tolerated in elderly patients. New, less invasive modalities are being developed to diagnose moderate-sized adenomatous polyps and colorectal cancers which involve pneumo-or hydrocolography with high-resolution surface imaging, either by CT or MR scanning. This approach has recently been supplemented by complex image post-processing to provide a form of virtual colonoscopy which takes account of projected colonic direction and which can map for mucosal anomalies. It remains to be seen how sensitive these newer techniques are and whether defined algorithms for colonic representation can be agreed upon which will prove both accurate and costeffective both in symptomatic and screening populations.

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Virtual colonoscopy and colorectal cancer screening

Cited by 26 publications

References 13 publications

Edge displacement field-based classification for improved detection of polyps in CT colonography

Edge displacement field-based classification for improved detection of polyps in CT colonography

Development of contrast-enhanced virtual MR cholangioscopy: a feasibility study

Pneumocolography and virtual colonoscopy: its clinical place and development

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