Computer-aided diagnosis in contrast-enhanced CT colonography: an approach based on contrast

Luboldt, Wolfgang; Mann, Carolin; Tryon, Cathy L.; Vonthein, Reinhard; Stueker, Dietmar; Kroll, Manuela; Luz, Oliver; Claussen, Claus D.; Vogl, Thomas J.

doi:10.1007/s00330-002-1377-3

Cited by 24 publications

(11 citation statements)

References 11 publications

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“…Computed tomographic colonography (CT colonography) is a non-invasive imaging technique for the evaluation of patients with suspected colorectal tumours [1] or polyps [2][3][4][5][6][7]. The technique has furthermore also been evaluated as an alternative to a barium enema after incomplete colonoscopy.…”

Section: Introductionmentioning

confidence: 99%

Supine/left decubitus scanning: a valuable alternative to supine/prone scanning in CT colonography

et al. 2004

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The purpose was to evaluate supine/left decubitus as an alternative to supine/prone scanning in computed tomographic colonography (CT colonography). Fifty patients were randomised to supine/prone, another 50 to supine/left decubitus scanning. Patients were scanned using a single-slice CT scanner. The colon was divided into eight segments. Comparisons of distension, breathing artefacts, residus and polyp detection were made between the two groups as well as between the different positions. Adequate distension was found in approximately 85, 97 and 95% of segments in the supine, prone and left decubitus positions, respectively. Combined scanning increased the percentage of adequate distension to 98.5% for prone-supine and 97.7% for left decubitus-supine scanning ( P<0.0005 compared to supine, P=0.001 compared to left decubitus and P=0.046 compared to prone scanning). Absence of residual material was found in approximately 62.7, 69.7 and 64% of segments in the supine, prone and left decubitus positions, respectively. Combined scanning increased this percentage to approximately 99% for both groups. No significant differences towards distension or residual material were found between combined supine-prone or supine-left decubitus scanning. In the supine-prone group, combined scanning additionally revealed four lesions and improved conspicuity in two cases of stalked polyps. In the supine-left decubitus group, combined scanning additionally revealed two lesions and improved conspicuity in one stalked polyp. There were significantly fewer breathing artefacts with left decubitus scanning than prone scanning ( P=0.005). A strong positive correlation was found between breathing artefacts and the age of patients in both patient groups. Colonic distension and preparation is improved by using supine and prone or supine and left decubitus scanning in combination, with a subsequent improved polyp detection. There were no significant differences between the two scanning protocols. Prone scanning, however, is hampered by breathing artefacts, especially in the elderly. Therefore, supine-left decubitus scanning is considered a valuable alternative to supine-prone scanning for the elderly.

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Section: Introductionmentioning

confidence: 99%

Supine/left decubitus scanning: a valuable alternative to supine/prone scanning in CT colonography

et al. 2004

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“…3). Thus, the voxel-based summation of CT values results in a new cut-off value that combines information about the CT value [4] with information about the volume [23]. In this manner higher CT values can compensate for a lower number of voxels in polyps and, vice versa, a larger volume can compensate lower CT values in carcinomas.…”

Section: Cadmentioning

confidence: 95%

“…Mostly CT colonography has been optimized and tested for screening purposes so that iv contrast agents have not been used. Consequently, there are only sparse data on the enhancement of colorectal polyps/carcinomas [3][4][5][6], and most of them were obtained with an iodine injection rate much smaller than 1.6 g/s. However, intravenous iodine administration in CT colonography has been proposed for problem solving in screening [3] and is justified for a variety of clinical indications discussed below.…”

Section: Introductionmentioning

confidence: 98%

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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“…By providing virtual perspectives that simulate the anatomical and pathological reality in a patient and by allowing interactive control on rendering parameters, computer-assisted three-dimensional reconstruction of imaging data sets has enabled the creation of a virtual reality environment, the utilization of which assists the determination of the diagnosis and preoperative planning [1][2][3]. Furthermore, operating in a virtual reality environment is becoming a more attractive and more reliable option for surgical training, planning of surgical procedures and predicting surgical outcomes of orthopedic operations [4,5].…”

Section: Introductionmentioning

confidence: 99%

CT virtual reality in the preoperative workup of malunited distal radius fractures: preliminary results

et al. 2004

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Our objective was to evaluate the usefulness of CT virtual preoperative planning in the surgical repositioning of malunited distal radius fracture. Eleven patients with malunited distal radius fracture underwent multislice CT of both wrists. A preoperative workup was performed in a virtual reality environment created from the CT data sets. Virtual planning comprised three main procedures, carrying out the virtual osteotomy of the radius, prediction of the final position of the distal radius after osteotomy and computer-assisted manufacturing of a repositioning device, which was later placed at the surgical osteotomy site to reposition objectively the distal radius fragment before fixation with the osteosynthesis. All patients tolerated the surgical procedure well. During surgery, the orthopedic surgeons were not required in any of the cases to alter the position of the distal radius that was determined by the repositioning device. At postoperative follow-up, the anatomic relationship of the distal radius was restored (radial inclination, 21.4 degrees ; volar tilt, 10.3 degrees ; ulnar variance, 0.5 mm). Clinically, a significant improvement of pronation (P=0.012), supination (P=0.01), flexion (P=0.001) and extension (P=0.006) was achieved. Pain decreased from 54 to 7 points. CT virtual reality is a valuable adjunct for the preoperative workup and surgical reposition of malunited distal radius fractures.

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Computer-aided diagnosis in contrast-enhanced CT colonography: an approach based on contrast

Cited by 24 publications

References 11 publications

Supine/left decubitus scanning: a valuable alternative to supine/prone scanning in CT colonography

Supine/left decubitus scanning: a valuable alternative to supine/prone scanning in CT colonography

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

CT virtual reality in the preoperative workup of malunited distal radius fractures: preliminary results

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