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[Optimization of the technique of virtual colonoscopy using a multislice spiral computerized tomography].
Radiol Med. 2000 Dec; 100(6):459-64.RM

Abstract

PURPOSE

To optimize scanning parameters for virtual colonoscopy utilizing a multislice Helical CT scanner in an in vitro study (using a homemade colonic phantom) and in a preliminary clinical study.

MATERIAL AND METHODS

A colonic phantom was built using a plastic tube and 12 plastiline polyps were placed inside. The colonic phantom was studied with a multislice Helical CT scanner. Axial images were obtained with the phantom parallel to the long axis of the moving table (in order to simulate the evaluation of ascending and descending colon): oblique images were acquired with the phantom at 45 degrees relative to the long axis of the moving table (in order to simulate the evaluation of sigmoid colon and colonic flexures). Four different scanning protocols were tested: 1) slice collimation, 5 mm; slice width, 7 mm; table speed, 25 mm; reconstruction index, 5 mm; 2) slice collimation, 2.5 mm; slice width, 3 mm; table speed, 15 mm; reconstruction index, 3 mm; 3) slice collimation, 1 mm; slice width, 1.25 mm; table speed, 5 mm; reconstruction index, 1 mm; 4) slice collimation, 1 mm; slice width, 1.25 mm; table speed, 4 mm; reconstruction index, 1 mm. Quantitative analysis consisted in evaluation of the number of identified polyps and polyp size along the longitudinal axis. Qualitative analysis consisted in the evaluation of image artifacts and quality of 3D reconstructed images (step artifacts and polyp geometry distortion). This preliminary clinical study was performed in 12 patients (7 men and 5 women) who underwent multislice Helical CT colonography. We selected patients with clinical indications for conventional colonoscopy or after unsuccessful conventional colonoscopy.

RESULTS

Multislice Helical CT colonography was 100% sensitive in the detection of all polyps and in all scanning protocols. With oblique scans, only a 3-mm polyp was missed during protocol 1 (sensitivity: 92%). Polyp geometry distortion was observed on longitudinal reconstructions, whereas no distortion was seen on axial images. Image quality was graded as optimal for protocols 2, 3, and 4; protocol 1 was graded as good on transverse scans and as poor on oblique scans. In our preliminary clinical study, two colonic carcinomas and three polyps were identified.

CONCLUSIONS

At present, the introduction of multislice technology in virtual colonoscopy permits to improve spatial resolution and image definition. The actual clinical advantage, in terms of increased diagnostic accuracy, needs further investigation in larger clinical studies.

Authors+Show Affiliations

Istituto di Radiologia, II Cattedra, Università degli Studi di Roma La Sapienza, Roma. andrea.laghi@mail.uniromal.itNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Evaluation Study
Journal Article

Language

ita

PubMed ID

11307507

Citation

Laghi, A, et al. "[Optimization of the Technique of Virtual Colonoscopy Using a Multislice Spiral Computerized Tomography]." La Radiologia Medica, vol. 100, no. 6, 2000, pp. 459-64.
Laghi A, Catalano C, Panebianco V, et al. [Optimization of the technique of virtual colonoscopy using a multislice spiral computerized tomography]. Radiol Med. 2000;100(6):459-64.
Laghi, A., Catalano, C., Panebianco, V., Iannaccone, R., Iori, S., & Passariello, R. (2000). [Optimization of the technique of virtual colonoscopy using a multislice spiral computerized tomography]. La Radiologia Medica, 100(6), 459-64.
Laghi A, et al. [Optimization of the Technique of Virtual Colonoscopy Using a Multislice Spiral Computerized Tomography]. Radiol Med. 2000;100(6):459-64. PubMed PMID: 11307507.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [Optimization of the technique of virtual colonoscopy using a multislice spiral computerized tomography]. AU - Laghi,A, AU - Catalano,C, AU - Panebianco,V, AU - Iannaccone,R, AU - Iori,S, AU - Passariello,R, PY - 2001/4/20/pubmed PY - 2001/5/22/medline PY - 2001/4/20/entrez SP - 459 EP - 64 JF - La Radiologia medica JO - Radiol Med VL - 100 IS - 6 N2 - PURPOSE: To optimize scanning parameters for virtual colonoscopy utilizing a multislice Helical CT scanner in an in vitro study (using a homemade colonic phantom) and in a preliminary clinical study. MATERIAL AND METHODS: A colonic phantom was built using a plastic tube and 12 plastiline polyps were placed inside. The colonic phantom was studied with a multislice Helical CT scanner. Axial images were obtained with the phantom parallel to the long axis of the moving table (in order to simulate the evaluation of ascending and descending colon): oblique images were acquired with the phantom at 45 degrees relative to the long axis of the moving table (in order to simulate the evaluation of sigmoid colon and colonic flexures). Four different scanning protocols were tested: 1) slice collimation, 5 mm; slice width, 7 mm; table speed, 25 mm; reconstruction index, 5 mm; 2) slice collimation, 2.5 mm; slice width, 3 mm; table speed, 15 mm; reconstruction index, 3 mm; 3) slice collimation, 1 mm; slice width, 1.25 mm; table speed, 5 mm; reconstruction index, 1 mm; 4) slice collimation, 1 mm; slice width, 1.25 mm; table speed, 4 mm; reconstruction index, 1 mm. Quantitative analysis consisted in evaluation of the number of identified polyps and polyp size along the longitudinal axis. Qualitative analysis consisted in the evaluation of image artifacts and quality of 3D reconstructed images (step artifacts and polyp geometry distortion). This preliminary clinical study was performed in 12 patients (7 men and 5 women) who underwent multislice Helical CT colonography. We selected patients with clinical indications for conventional colonoscopy or after unsuccessful conventional colonoscopy. RESULTS: Multislice Helical CT colonography was 100% sensitive in the detection of all polyps and in all scanning protocols. With oblique scans, only a 3-mm polyp was missed during protocol 1 (sensitivity: 92%). Polyp geometry distortion was observed on longitudinal reconstructions, whereas no distortion was seen on axial images. Image quality was graded as optimal for protocols 2, 3, and 4; protocol 1 was graded as good on transverse scans and as poor on oblique scans. In our preliminary clinical study, two colonic carcinomas and three polyps were identified. CONCLUSIONS: At present, the introduction of multislice technology in virtual colonoscopy permits to improve spatial resolution and image definition. The actual clinical advantage, in terms of increased diagnostic accuracy, needs further investigation in larger clinical studies. SN - 0033-8362 UR - https://www.unboundmedicine.com/medline/citation/11307507/[Optimization_of_the_technique_of_virtual_colonoscopy_using_a_multislice_spiral_computerized_tomography]_ L2 - https://medlineplus.gov/colonicpolyps.html DB - PRIME DP - Unbound Medicine ER -