Multidetector CT of the colon

Luboldt, Wolfgang; Hoepffner, N.; Holzer, Katharina

doi:10.1007/s00330-003-2101-7

Cited by 4 publications

(5 citation statements)

References 25 publications

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“…These include the use of reduced colon cleansing to reduce the amount of fluid [35,36], the added use of oral iodinated contrast material to tag residual fluid [37], the use of barium [22] or iodinated contrast material to tag residual stool [38], the use of multidetector CT to optimize resolution and decrease scan time [39], the combined use of prone and supine, or supine and left decubitus scanning [40,41], and the use of smooth muscle relaxant [42,43] to optimize distention. All these technical parameters have been used and optimized in patients where conventional colonoscopy was complete.…”

Section: Discussionmentioning

confidence: 99%

CT colonography with fecal tagging after incomplete colonoscopy

Gryspeerdt

Lefere²,

Herman³

et al. 2005

Eur Radiol

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The objective of this study was to evaluate dietary fecal tagging (FT) as a cleansing method prior to CT colonography (CTC) in patients with incomplete conventional colonoscopy (CC). After written informed consent was obtained, 24 patients had standard colonoscopic preparation (ScCl), and 25 patients had FT as cleansing method. Segmental distention, fluid levels, fecal residues, tagged appearance of fluid levels, and residual stool were evaluated. Mann-Whitney U test was used to test for significant differences between FT and ScCl groups. Compared with ScCl, FT improved distention (p=0.001), reduced the amount of fluid (p=0.043), but suffered from residual stool (p=0.046). A clear correlation was found between distention and fluid. No differences were found in stool size between FT and ScCl. FT showed a good labeling of fecal residues, and acceptable labeling of fluid levels. Compared with ScCl, FT reduces fluid, favors distention, but suffers from fecal residues. The tagged nature of these residues, however, allows differentiation from polyps.

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Section: Discussionmentioning

confidence: 99%

CT colonography with fecal tagging after incomplete colonoscopy

Gryspeerdt

Lefere²,

Herman³

et al. 2005

Eur Radiol

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“…However, due to potential nephrotoxicity and, in particular, due to the risk of adverse events [22], using IV contrast agents in CTC is possibly not justified for screening. However, many clinical indications justify its use: the search for primary cancer, the exclusion of cancer in case of symptoms as well as the staging and surveillance of colorectal cancer [23][24][25]. Furthermore, if a contrast-enhanced CT of the abdomen is necessary for other medical reasons, combining this primary examination with a colorectal screening is possible in one session.…”

Section: Contrastmentioning

confidence: 99%

Automated mass detection in contrast-enhanced CT colonography: an approach based on contrast and volume

et al. 2004

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The purpose of this feasibility study was to design and test an algorithm for automating mass detection in contrast-enhanced CT colonography (CTC). Five patients with known colorectal masses underwent a pre-surgical contrast-enhanced (120 ml volume 1.6 g iodine/s injection rate, 60 s scan delay) CTC in high spatial resolution (16-slice CT: collimation: 16x0.75 mm, tablefeed: 24 mm/0.5 s, reconstruction increment: 0.5 mm). A CT-density- and volume-based algorithm searched for masses in the colonic wall, which was extracted before by segmenting and dilating the colonic air lumen and subtracting the inner air. A radiologist analyzed the detections and causes of false positives. All masses were detected, and false positives were easy to identify. Combining CT density with volume as a cut-off is a promising approach for automating mass detection that should be further refined and also tested in contrast-enhanced MR colonography. More information under http://www.screening.info.

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“…Before positioning on the scanner table, patients were asked to drink as much water as possible to enable better assessment of the 2229 stomach and pancreas and to reduce the reflux of air from the large into the small intestine [8,9]. In the supine position, patients' colons were distended by rectal insufflation of air to the point of discomfort via a non-blocked enema tip.…”

Section: Methodsmentioning

confidence: 99%

“…However, due to potential nephrotoxicity and, in particular, due to the risk of adverse events [18][19][20], using contrast agents in CT colonography is possibly not justified in a screening population without symptoms or increased risk of developing colorectal cancer. Yet, many clinical indications justify its use [9,21]: -the search for primary cancer, -the exclusion of cancer in case of symptoms (weight loss, anemia, abdominal pain), -the staging and surveillance of colorectal cancer and -if colonoscopy is refused, inadequate, contraindicated or incomplete.…”

Section: Indications For Contrast-enhanced Ctcmentioning

confidence: 99%

Phase- and size-adjusted CT cut-off for differentiating neoplastic lesions from normal colon in contrast-enhanced CT colonography

et al. 2004

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A computed tomography (CT) cut-off for differentiating neoplastic lesions (polyps/carcinoma) from normal colon in contrast-enhanced CT colonography (CTC) relating to the contrast phase and lesion size is determined. CT values of 64 colonic lesions (27 polyps <10 mm, 13 polyps > or =10 mm, 24 carcinomas) were determined by region-of-interest (ROI) measurements in 38 patients who underwent contrast-enhanced CTC. In addition, the height (H) of the colonic lesions was measured in CT. CT values were also measured in the aorta (A), superior mesenteric vein (V) and colonic wall. The contrast phase was defined by xA + (1-x)V using x as a weighting factor for describing the different contrast phases ranging from the pure arterial phase (x=1) over the intermediate phases (x=0.9-0.1) to the pure venous phase (x=0). The CT values of the lesions were correlated with their height (H), the different phases (xA+(1-x)V) and the ratio [xA+(I-x)V]/H. The CT cut-off was linearly adjusted to the imaged contrast phase and height of the lesion by the line y=m[xA+(1-x)V]H+y(0). The slope m was determined by linear regression in the correlation (lesion approximately [xA+(i-x)V]/H) and the Y-intercept y(0) by the minimal shift of the line needed to maximize the accuracy of separating the colonic wall from the lesions. The CT value of the lesions correlated best with the intermediate phase: 0.4A + 0.6V (r=0.8 for polyps > or =10 mm, r=0.6 for carcinomas, r=0.4 for polyps <10 mm). The accuracy in the differentiation between lesions and normal colonic wall increased with the height implemented as divisor, reached 91% and was obtained by the dynamic cut-off described by the formula: cut-off (A,V,H)=1.1 [0.4A+0.6V]/H+69.8. The CT value of colonic polyps or carcinomas can be increased extrinsically by scanning in the phase in which 0.4A + 0.6V reaches its maximum. Differentiating lesions from normal colon based on CT values is possible in contrast-enhanced CTC and improves when the cut-off is adjusted (normalized) to the contrast phase and lesion size.

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Multidetector CT of the colon

Cited by 4 publications

References 25 publications

CT colonography with fecal tagging after incomplete colonoscopy

CT colonography with fecal tagging after incomplete colonoscopy

Automated mass detection in contrast-enhanced CT colonography: an approach based on contrast and volume

Phase- and size-adjusted CT cut-off for differentiating neoplastic lesions from normal colon in contrast-enhanced CT colonography

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