Article

Computed tomographic colonography without cathartic preparation for the detection of colorectal polyps.

Department of Radiological Sciences, University of Rome, Rome, Italy.
Gastroenterology (Impact Factor: 13.93). 11/2004; 127(5):1300-11. DOI: 10.1053/j.gastro.2004.08.025
Source: PubMed

ABSTRACT We prospectively compared the performance of low-dose multidetector computed tomographic colonography (CTC) without cathartic preparation with that of colonoscopy for the detection of colorectal polyps.
A total of 203 patients underwent low-dose CTC without cathartic preparation followed by colonoscopy. Before CTC, fecal tagging was achieved by adding diatrizoate meglumine and diatrizoate sodium to regular meals. No subtraction of tagged feces was performed. Colonoscopy was performed 3-7 days after CTC. Three readers interpreted the CTC examinations separately and independently using a primary 2-dimensional approach using multiplanar reconstructions and 3-dimensional images for further characterization. Colonoscopy with segmental unblinding was used as reference standard. The sensitivity of CTC was calculated both on a per-polyp and a per-patient basis. For the latter, specificity, positive predictive values, and negative predictive values were also calculated.
CTC had an average sensitivity of 95.5% (95% confidence interval [CI], 92.1%-99%) for the identification of colorectal polyps > or =8 mm. With regard to per-patient analysis, CTC yielded an average sensitivity of 89.9% (95% CI, 86%-93.7%), an average specificity of 92.2% (95% CI, 89.5%-94.9%), an average positive predictive value of 88% (95% CI, 83.3%-91.5%), and an average negative predictive value of 93.5% (95% CI, 90.9%-96%). Interobserver agreement was high on a per-polyp basis (kappa statistic range, .61-.74) and high to excellent on a per-patient basis (kappa statistic range, .79-.91).
Low-dose multidetector CTC without cathartic preparation compares favorably with colonoscopy for the detection of colorectal polyps.

0 Followers
 · 
120 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aim To compare two regimens of reduced bowel preparation and faecal tagging for CT colonography. Materials and methods Single centre, prospective, randomized, noninferiority study, in which 52 consecutive adults underwent routine CT colonography. Patients, following a three-day low-fibre diet, received one of the two reduced preparations: 1-L polyethylene glycol and four tablets of bisacodyl in association with 90 mL of Iopamidol for faecal tagging administered on the same day as CTC examination (group 1); or a standard "iodine-only" preparation, consisting in 180 ml of Iopamidol the day before the examination (group 2). Primary outcome was the overall quality of bowel preparation. Results Twenty-six patients per group were included. Per segment analysis showed preparation of diagnostic quality in 97.4 % of segments in group 1 and in 95.5 % in group 2 (p = ns). Per-patient analysis showed optimal quality of preparation in 76.9 % of patients in group 1 and in 84.6 % in group 2 (p = ns). Patient tolerability to both preparations was not different. Conclusion A limited bowel preparation consisting of 1-L PEG and four tablets of bisacodyl in association with 90 mL of Iodine for faecal tagging administered on the same day as CTC examination is feasible and offers bowel cleansing comparable to "iodine-only" preparation. Key Points • Low-dose PEG bisacodyl and Iopamidol preparation is feasible, providing adequate bowel cleansing. • Faecal tagging is not different from the two limited preparations. • Patient tolerability to the two colon cleansing regimens is similar.
    European Radiology 08/2014; 25(1). DOI:10.1007/s00330-014-3345-0 · 4.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Twenty years after its introduction, computed tomographic colonography (CTC) has reached its maturity, and it can reasonably be considered the best radiological diagnostic test for imaging colorectal cancer (CRC) and polyps. This examination technique is less invasive than colonoscopy (CS), easy to perform, and standardized. Reduced bowel preparation and colonic distention using carbon dioxide favor patient compliance. Widespread implementation of a new image reconstruction algorithm has minimized radiation exposure, and the use of dedicated software with enhanced views has enabled easier image interpretation. Integration in the routine workflow of a computer-aided detection algorithm reduces perceptual errors, particularly for small polyps. Consolidated evidence from the literature shows that the diagnostic performances for the detection of CRC and large polyps in symptomatic and asymptomatic individuals are similar to CS and are largely superior to barium enema, the latter of which should be strongly discouraged. Favorable data regarding CTC performance open the possibility for many different indications, some of which are already supported by evidence-based data: incomplete, failed, or unfeasible CS; symptomatic, elderly, and frail patients; and investigation of diverticular disease. Other indications are still being debated and, thus, are recommended only if CS is unfeasible: the use of CTC in CRC screening and in surveillance after surgery for CRC or polypectomy. In order for CTC to be used appropriately, contraindications such as acute abdominal conditions (diverticulitis or the acute phase of inflammatory bowel diseases) and surveillance in patients with a long-standing history of ulcerative colitis or Crohn's disease and in those with hereditary colonic syndromes should not be overlooked. This will maximize the benefits of the technique and minimize potential sources of frustration or disappointment for both referring clinicians and patients.
    World Journal of Gastroenterology 12/2014; 20(45):16858-16867. DOI:10.3748/wjg.v20.i45.16858 · 2.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dual-energy CT provides a promising solution to identify tagged fecal materials in electronic cleansing (EC) for fecal-tagging CT colonography (CTC). In this study, we developed a new EC method based on virtual colon tagging (VCT) for minimizing EC artifacts by use of the material decomposition ability in dual-energy CTC images. In our approach, a localized three-material decomposition model decomposes each voxel into a material mixture vector and the first partial derivatives of three base materials: luminal air, soft tissue, and iodine-tagged fecal material. A Poisson-based derivative smoothing algorithm smoothes the derivatives and implicitly smoothes the associated material mixture fields. VCT is a means for marking the entire colonic lumen by virtually elevating the CT value of luminal air as high as that of the tagged fecal materials to differentiate effectively soft-tissue structures from air-tagging mixtures. A dual-energy EC scheme based on VCT method, denoted as VCT-EC, was developed, in which the colonic lumen was first virtually tagged and then segmented by its high values in VCT images. The performance of the VCT-EC scheme was evaluated in a phantom study and a clinical dual-energy fecal-tagging CTC study. Our results demonstrated that our VCT-EC scheme may provide a significant reduction of EC artifacts.
    IEEE transactions on bio-medical engineering 10/2014; 62(2). DOI:10.1109/TBME.2014.2364837 · 2.23 Impact Factor

Full-text (2 Sources)

Download
98 Downloads
Available from
May 31, 2014