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Measurement of circumferential tumor extent of colorectal cancer on CT colonography: relation to clinicopathological features and patient prognosis after surgery. Jpn J Radiol 2021; 39:966-972. [PMID: 34021856 DOI: 10.1007/s11604-021-01141-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 05/17/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE To examine the relationship between circumferential tumor extent of colorectal cancer (CRC) on CT colonography (CTC) and clinicopathological features including patient prognosis after surgery. MATERIALS AND METHODS This retrospective study performed at our institution from January 2013 to December 2019 enrolled 195 consecutive patients (110 men, 85 women; mean age, 64.7 years) with CRC evaluated by contrast-enhanced CTC before surgery. The circumferential tumor extent rate (CER) was measured by CTC in virtual colon dissection (VCD) mode to examine the relation between the CER and clinicopathological features and patient prognosis. RESULTS CER had association with tumor invasion depth (T), nodal involvement (N), distant metastasis (M), and stage. The Kruskal-Wallis tests showed significant difference for T, N and the stage (p < 0.0001, p = 0.0021 and p < 0.0001) and Wilcoxon rank sum test showed significant difference for M (p = 0.0015). According to the log-rank test, there were no significant differences in OS or DFS between patients with high and low CER. CONCLUSION Circumferential tumor extent was significantly correlated with TNM categories and stage of CRC, but not with patient prognosis after surgery.
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Song Y, Lee H, Kang HC, Shin J, Hong GS, Park SH, Lee J, Shin YG. Interactive registration between supine and prone scans in computed tomography colonography using band-height images. Comput Biol Med 2017; 80:124-136. [DOI: 10.1016/j.compbiomed.2016.11.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/30/2016] [Accepted: 11/30/2016] [Indexed: 01/12/2023]
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Schmidt SA, Ernst AS, Beer M, Juchems MS. 3D detection of colonic polyps by CT colonography: accuracy, pitfalls, and solutions by adjunct 2D workup. Clin Radiol 2015. [PMID: 26220124 DOI: 10.1016/j.crad.2015.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Computed tomography colonography (CTC) enables evaluation of the colon with minimal invasiveness. In spite of advances in multidetector CT (MDCT) technology and advanced software features, including electronic bowel cleansing (digital removal and tagging of fluid and debris), a number of potential pitfalls in the evaluation of the 3D volumetric dataset persist. The purpose of this article is to illustrate the strengths and potential pitfalls in the detection of colorectal polyps using CTC via a primary three-dimensional (3D) approach for evaluation.
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Affiliation(s)
- S A Schmidt
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
| | - A S Ernst
- Department of Radiology, Donauklinik Neu-Ulm, Krankenhausstrasse 11, D-89231 Neu-Ulm, Germany
| | - M Beer
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - M S Juchems
- Department of Diagnostic and Interventional Radiology, Konstanz Hospital, Luisenstrasse 7, D-87464 Konstanz, Germany
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Tsurumaru D, Kawanami S, Nishimuta Y, Miyasaka M, Asayama Y, Honda H. Contrast-Enhanced CT Colonography Features of Rectal Carcinoid Tumors. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/act.2014.32005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ganeshan D, Elsayes KM, Vining D. Virtual colonoscopy: Utility, impact and overview. World J Radiol 2013; 5:61-7. [PMID: 23671742 PMCID: PMC3650206 DOI: 10.4329/wjr.v5.i3.61] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 09/13/2012] [Accepted: 01/31/2013] [Indexed: 02/06/2023] Open
Abstract
Computed tomography (CT) colonoscopy is a well-established technique for evaluation of colorectal cancer. Significant advances have been made in the technique of CT colonoscopy since its inception. Excellent results can be achieved in detecting both colorectal cancer and significant sized polyps as long as a meticulous technique is adopted while performing CT colonoscopy. Furthermore, it is important to realize that there is a learning curve involved in interpreting these studies and adequate experience is essential to achieve high sensitivity and specificity with this technique. Indications, contraindications, technique and interpretation, including potential pitfalls in CT colonoscopy imaging, are reviewed in this article. Recent advances and the current role of CT colonoscopy in colorectal cancer screening are also discussed.
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Oh SN, Lee YJ, Kim YS, Jung SE, Rha SE, Shin YR, Byun JY, Choi BG. A feasibility study of unidirectional 240°-angle 3D CT colonography. Clin Imaging 2012; 36:553-8. [PMID: 22920361 DOI: 10.1016/j.clinimag.2012.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 01/04/2012] [Indexed: 11/26/2022]
Abstract
In three-dimensional (3D) CT colonography (CTC), a wider viewing angle provides a larger field of view. The purpose of this study was to investigate the polyp detection rate and time efficiency of unidirectional 240°-angle 3D CTC compared with bidirectional 120°-angle CTC. CTC data sets of 40 patients were reviewed by two readers using the two methods. The unidirectional 240°-angle CTC showed a performance in polyp detection similar to the bidirectional 120°-angle CTC with improved time efficiency.
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Affiliation(s)
- Soon Nam Oh
- Department of Radiology, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
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“Calvarial Butterfly” new multidetector computed tomography (MDCT) virtual osteoscopic (VO) fingerprint for identification. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2012. [DOI: 10.1016/j.ejrnm.2012.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Cash BD, Rockey DC, Brill JV. AGA standards for gastroenterologists for performing and interpreting diagnostic computed tomography colonography: 2011 update. Gastroenterology 2011; 141:2240-66. [PMID: 22098711 DOI: 10.1053/j.gastro.2011.09.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Brooks D Cash
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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Mang T, Kolligs FT, Schaefer C, Reiser MF, Graser A. Comparison of diagnostic accuracy and interpretation times for a standard and an advanced 3D visualisation technique in CT colonography. Eur Radiol 2010; 21:653-62. [PMID: 20890763 DOI: 10.1007/s00330-010-1953-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Revised: 08/06/2010] [Accepted: 08/07/2010] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To compare the diagnostic accuracy of a standard bi-directional, three-dimensional (3D) CT colonography (CTC) fly-through (standard view, SV) with a unidirectional, 3D unfolding technique (panoramic view, PV). METHODS 150 consecutive endoscopically-validated CTC patient datasets were retrospectively reviewed twice by two expert radiologists: first, with bidirectional SV, second, after 6-15 months, with unidirectional PV. Per-polyp sensitivities, percentage of visualised colonic mucosa, and reading times were calculated for both 3D visualisations. Results were tested for statistical significance by equivalence analysis for paired proportions and Student's paired t-test. RESULTS In 81 patients, 236 polyps (101 adenomas, 135 non-adenomas) were detected. Sensitivities for polyps ≤5 mm, 6-9 mm and ≥10 mm were 60.1% (113/188), 92.9% (26/28) and 95.0% (19/20) with bidirectional SV, and 60.6% (114/188), 96.4% (27/28) and 95.0% (19/20) with unidirectional PV. Overall sensitivity for adenomas was 86.1% and 84.2% for SV and PV. Both methods provided equivalent polyp detection, with an equivalence limit set at 5%. PV and SV visualised 98.9 ± 1.1% (97.0-99.9%) and 96.2 ± 2.3% (91.4-98.8%) of the colonic mucosa (p > 0.05). Mean interpretation time decreased from 14.6 ± 2.5 (9.2-22.8) minutes with SV to 7.5 ± 3.2 (5.0-14.4) using PV (p < 0.0001). CONCLUSION 3D CTC interpretation using unidirectional PV is equally as accurate, but significantly faster than an interpretation based on bidirectional SV.
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Affiliation(s)
- Thomas Mang
- Department of Radiology, Medical University of Vienna, Waehringer Guertel, 18-20, 1090, Vienna, Austria.
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Christensen KN, Fidler JL, Fletcher JG, MacCarty R, Johnson CD. Pictorial Review of Colonic Polyp and Mass Distortion and Recognition with the CT Virtual Dissection Technique. Radiographics 2010; 30:e42; discussion e43. [DOI: 10.1148/rg.e42] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Yao J, Chowdhury AS, Aman J, Summers RM. Reversible projection technique for colon unfolding. IEEE Trans Biomed Eng 2010; 57:2861-9. [PMID: 20542756 DOI: 10.1109/tbme.2010.2052255] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Colon unfolding provides an efficient way to navigate the colon in computed tomographic colonography (CTC). Most existing unfolding techniques only compute forward projections. When radiologists find abnormalities or conduct measurements on the unfolded view (which is often quicker and easier), it is difficult to locate the corresponding region on the 3-D view for further examination (which is more accurate and reliable). To address this, we propose a reversible projection technique for colon unfolding. The method makes use of advanced algorithms including rotation-minimizing frames, recursive ring sets, mesh skinning, and cylindrical projection. Both forward and reverse mapping can be computed for points on the colon surface. Therefore, it allows for detecting and measuring polyps on the unfolded view and mapping them back to the 3-D surface. We generated realistic colon simulation data incorporating most colon characteristics, such as curved centerline, variable distention, haustral folds, teniae coli, and colonic polyps. Our method was tested on both simulated data and data from 110 clinical CTC studies. The results showed submillimeter accuracy in simulated data and -0.23 ± 1.67 mm in the polyp measurement using clinical CTC data. The major contributions of our technique are: 1) the use of a recursive ring set method to solve the centerline and surface correspondence problem; 2) reverse transformation from the unfolded view to the 3-D view; and 3) quantitative validation using a realistic colon simulation and clinical CTC polyp measurement.
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Affiliation(s)
- Jianhua Yao
- Clinical Image-Processing Laboratory, National Institutes of Health, Bethesda, MD 20892, USA.
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Abstract
Computer-aided polyp detection aims to improve the accuracy of the colonography interpretation. The computer searches the colonic wall to look for polyplike protrusions and presents a list of suspicious areas to a physician for further analysis. Computer-aided polyp detection has developed rapidly in the past decade in the laboratory setting and has sensitivities comparable with those of experts. Computer-aided polyp detection tends to help inexperienced readers more than experienced ones and may also lead to small reductions in specificity. In its currently proposed use as an adjunct to standard image interpretation, computer-aided polyp detection serves as a spellchecker rather than an efficiency enhancer.
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Affiliation(s)
- Ronald M Summers
- Imaging Biomarkers and Computer-Aided Diagnosis Laboratory, Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Building 10, Room 1C368X MSC 1182, Bethesda, MD 20892-1182, USA.
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Current techniques in the performance, interpretation, and reporting of CT colonography. Gastrointest Endosc Clin N Am 2010; 20:169-92. [PMID: 20451809 DOI: 10.1016/j.giec.2010.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The technical objective of computed tomographic colonography (CTC) is to acquire high-quality computed tomography images of the cleansed, well-distended colon for polyp detection. In this article the authors provide an overview of the technical components of CTC, from preparation of the patient to acquisition of the imaging data and basic methods of interpretation. In each section, the best evidence for current practices and recommendations is reviewed. Each of the technical components must be optimized to achieve high sensitivity in polyp detection.
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Lenhart DK, Babb J, Bonavita J, Kim D, Bini EJ, Megibow AJ, Macari M. Comparison of a unidirectional panoramic 3D endoluminal interpretation technique to traditional 2D and bidirectional 3D interpretation techniques at CT colonography: preliminary observations. Clin Radiol 2009; 65:118-25. [PMID: 20103433 DOI: 10.1016/j.crad.2009.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 11/03/2009] [Accepted: 11/10/2009] [Indexed: 11/15/2022]
Abstract
AIM To compare the evaluation times and accuracy of unidirectional panoramic three-dimensional (3D) endoluminal interpretation to traditional two-dimensional (2D) and bidirectional 3D endoluminal techniques. MATERIALS AND METHODS Sixty-nine patients underwent computed tomography colonography (CTC) after bowel cleansing. Forty-five had no polyps and 24 had at least one polyp > or = 6 mm. Patients underwent same-day colonoscopy with segmental unblinding. Three experienced abdominal radiologists evaluated the data using one of three primary interpretation techniques: (1) 2D; (2) bidirectional 3D; (3) panoramic 3D. Mixed model analysis of variance and logistic regression for correlated data were used to compare techniques with respect to time and sensitivity and specificity. RESULTS Mean evaluation times were 8.6, 14.6, and 12.1 min, for 2D, 3D, and panoramic, respectively. 2D was faster than either 3D technique (p < 0.0001), and the panoramic technique was faster than bidirectional 3D (p = 0.0139). The overall sensitivity of each technique per polyp and per patient was 68.4 and 76.7% for 2D, 78.9 and 93.3% for 3D; and 78.9 and 86.7% for panoramic 3D. CONCLUSION 2D interpretation was the fastest overall, the panoramic technique was significantly faster than the bidirectional with similar sensitivity and specificity. The sensitivity for a single reader was significantly lower using the 2D technique. Each reader should select the technique with which they are most successful.
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Affiliation(s)
- D K Lenhart
- Department of Radiology, NYU Medical Center, New York, NY 10016, USA
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Juchems MS, Ernst A, Johnson P, Virmani S, Brambs HJ, Aschoff AJ. Electronic colon-cleansing for CT colonography: diagnostic performance. ACTA ACUST UNITED AC 2009; 34:359-64. [PMID: 18343970 DOI: 10.1007/s00261-008-9386-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND The purpose of this study was to evaluate whether an electronic-colonic-cleansing (ECC) algorithm is beneficial for the diagnostic performance compared to a CT colonography (CTC) evaluation without electronic cleansing in tagged datasets. METHODS Two blinded readers evaluated CTC datasets from 79 patients with 153 colorectal polyps confirmed by optical colonoscopy. Cases were read in a randomized order with and without the use of electronic colon-cleansing software. Per-polyp sensitivity, per-polyp/per-patient specificity and reading times (with and without ECC) have been calculated and reported. RESULTS Per-polyp sensitivity for polyps >6 mm without using ECC was 60.4% (Reader 1: 59.7%, Reader 2: 61.1%), while polyps >10 mm were detected with a sensitivity of 58.3% (Reader 1: 66.7%, Reader 2: 50%). On electronically cleansed datasets, the sensitivity was 73.6% (Reader 1: 76.4%; Reader 2: 70.8%) for polyps >6 mm and 83.3% (Reader 1: 83.3%; Reader 2: 83.3%), respectively. Per-patient specificity was 75% without using cleansing (Reader 1: 68%, Reader 2: 82%) and 81.5% using ECC (Reader 1: 86%, Reader 2: 77%). CONCLUSION Reading CTC cases using ECC software improves sensitivity in detecting clinically relevant colorectal polyps.
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Affiliation(s)
- Markus S Juchems
- Department for Diagnostic and Interventional Radiology, University Hospitals Ulm, Ulm, Germany.
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Polyp detection at 3-dimensional endoluminal computed tomography colonography: sensitivity of one-way fly-through at 120 degrees field-of-view angle. J Comput Assist Tomogr 2009; 33:631-5. [PMID: 19638863 DOI: 10.1097/rct.0b013e31819778ea] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate whether increasing the visual field-of-view (FOV) angle at 3-dimensional (3D) endoluminal computed tomography colonography (CTC) from 90 degrees to 120 degrees allows for single pass fly-through examination of the supine and prone views without sacrificing polyp detection. METHODS Primary 3D endoluminal CTC evaluation using a 120 degree FOV was performed by 2 experienced radiologists on 73 patients harboring 104 colonoscopy-proven polyps measuring 6 mm or larger. Unidirectional fly-through evaluation consisted of rectal-to-cecal (retrograde) navigation on the supine display and cecal-to-rectal (antegrade) navigation on the prone display. Electronic fluid subtraction was not used. RESULTS All 104 (100%) polyps were detectable with the single-pass 3D evaluation on either the retrograde supine or antegrade prone fly-through, with 86 (82.7%) of 104 polyps seen on both fly-through views. Of the 18 polyps detected on only one of the two 3D endoluminal passes (10 prone, 8 supine), 13 were either submerged under fluid (n = 12) or within a collapsed segment (n = 1); therefore, these were also undetectable on the corresponding 90 degrees bidirectional fly-through. The remaining 5 (4.8%) polyps were located behind a fold, but these polyps were all detectable on the other fly-through in the reverse direction. CONCLUSIONS Increasing the visual FOV angle to 120 degrees allows for a decrease in the total number of supine and prone 3D endoluminal fly-through passes from 4 to 2 without negatively impacting overall polyp detection.
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Fisichella VA, Jäderling F, Horvath S, Stotzer PO, Kilander A, Båth M, Hellström M. Computer-aided detection (CAD) as a second reader using perspective filet view at CT colonography: effect on performance of inexperienced readers. Clin Radiol 2009; 64:972-82. [PMID: 19748002 DOI: 10.1016/j.crad.2009.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 04/27/2009] [Accepted: 05/05/2009] [Indexed: 10/20/2022]
Abstract
AIM To evaluate whether computer-aided detection (CAD) as a second reader using perspective filet view [three-dimensional (3D) filet] improves the performance of inexperienced readers at computed tomography colonography (CTC) compared with unassisted 3D filet and unassisted two-dimensional (2D) CTC. MATERIAL AND METHODS Fifty symptomatic patients underwent CTC and same-day colonoscopy with segmental unblinding. Two inexperienced readers read the CTC studies on 3D filet and 2D several weeks apart. Four months later, readers re-read the cases only evaluating CAD marks using 3D filet. Suspicious CAD marks not previously described on 3D filet were recorded. Jackknife free-response receiver operating characteristic (JAFROC-1) analysis was used to compare the observers' performances in detecting lesions with 3D filet, 2D and 3D filet with CAD. RESULTS One hundred and three lesions > or =3mm were detected at colonoscopy with segmental unblinding. CAD alone had a sensitivity of 73% (75/103) at a mean false-positive rate per patient of 12.8 in supine and 11.4 in prone. For inexperienced readers sensitivities with 3D filet with CAD were 58% (60/103) and 48% (50/103) with an improvement of 14-16 percentage points (p<0.05) compared with 2D and of 10-11 percentage points (p<0.05) compared with 3D filet. For inexperienced readers, the false-positive rate was 25-41% and 71-200% higher with 3D filet with CAD compared with 3D filet and 2D, respectively. JAFROC-1 analysis showed no significant differences in per-lesion overall performance among reading modes (p=0.8). CONCLUSION CAD applied as a second reader using 3D filet increased both sensitivity and the number of false positives by inexperienced readers compared with 3D filet and 2D, thus not improving overall performance, i.e., the ability to distinguish between lesions and non-lesions.
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Affiliation(s)
- V A Fisichella
- Department of Radiology, Sahlgrenska University Hospital and Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
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Carrascosa P, López EM, Capuñay C, Vallejos J, Carrascosa J. Virtual colonoscopy in paediatric patients Usefulness of a colon dissection technique. Eur J Radiol 2009; 74:189-94. [PMID: 19345031 DOI: 10.1016/j.ejrad.2009.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 01/14/2009] [Accepted: 01/15/2009] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To determine the usefulness of perspective-filet view for polypoid lesions in paediatric patients in comparison with conventional virtual colonoscopy (VC) analysis and optical colonoscopy. METHODS Sixty-one patients (mean age 5 years old) with a previous episode of rectal bleeding were studied using a 16 slices CT scanner. All patients underwent a colonic preparation. Two acquisitions were done in supine and prone positions with slices of 2mm thickness; increment 1mm, 30-50mA; 90-120kV. In a workstation an experienced radiologist reviewed images twice. The first read was done using the conventional virtual colonoscopy technique with the evaluation of two-dimensional (2D), three-dimensional (3D) and endoscopical images. Later, in a second session, perspective-filet view was used. It shows a 360 degrees unrolled visualization of the inner colon. The presence, size and location of the lesions were determined. A record of the reading time was made. RESULTS At per patient evaluation the conventional virtual colonoscopy analysis obtained a sensitivity of 86% and a specificity of 98%. The perspective-filet view obtained a sensitivity of 91% and a specificity of 99%. In the evaluation on a per lesion basis the conventional analysis had a sensitivity of 81% and a specificity of 88%. Perspective-filet view, had a sensitivity of 82% and specificity of 90%. The average total reading time using conventional colonoscopy technique was 18+/-3min, versus 4+/-1min using the perspective-filet view. CONCLUSION Virtual colon dissection with perspective-filet view is more time-efficient than conventional virtual colonoscopy evaluation with correct correlation in results.
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Affiliation(s)
- Patricia Carrascosa
- Diagnóstico Maipú, Av. Maipú 1668, Vicente López (B1602ABQ), Buenos Aires, Argentina.
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Panoramic endoluminal display with minimal image distortion using circumferential radial ray-casting for primary three-dimensional interpretation of CT colonography. Eur Radiol 2009; 19:1951-9. [DOI: 10.1007/s00330-009-1362-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 12/28/2008] [Accepted: 01/10/2009] [Indexed: 10/21/2022]
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Igarashi T, Zenbutsu S, Yamanishi T, Naya Y. Three-dimensional image processing system for the ureter and urethra using endoscopic video. J Endourol 2008; 22:1569-72. [PMID: 18657032 DOI: 10.1089/end.2008.0150] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We developed new software that enables three-dimensional (3D) images of the ureter and urethra to be automatically processed from the video image of a conventional endoscope. The entire image of the ureter or urethra is displayed opened in a picture like a 3D map. The locations of lesions and the 3D structure of the prostatic urethra are depicted using this method, which enables quantitative evaluation of lesions and the obstructive potential of the prostatic urethra. Application of the technology in the urinary tract is discussed.
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Affiliation(s)
- Tatsuo Igarashi
- Research Center for Frontier Medical Engineering, Chiba University, Chiba City, Chiba, Japan.
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Hock D, Ouhadi R, Materne R, Aouchria AS, Mancini I, Broussaud T, Magotteaux P, Nchimi A. Virtual dissection CT colonography: evaluation of learning curves and reading times with and without computer-aided detection. Radiology 2008; 248:860-8. [PMID: 18710980 DOI: 10.1148/radiol.2482070895] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively evaluate the learning curves and reading times of inexperienced readers who used the virtual dissection reading method for retrospective computed tomographic (CT) colonography data sets, with and without concurrent computer-aided detection (CAD). MATERIALS AND METHODS An Institutional Review Board approved this study; informed consent was waived. Four radiologists without experience in CT colonography evaluated 100 optical colonoscopy-proved data sets of 100 patients (49 men, 51 women; mean age, 59 years +/- 13 [standard deviation]; range, 21-85 years) by using the virtual dissection reading method. Two readers used concurrent CAD. Data sets were read during five consecutive 1-day sessions (20 data sets per session). Polyp detection and false-positive rates, receiver operating characteristics (ROCs), and reading times were calculated for individual, CAD group, and non-CAD group readings. Diagnostic values were compared by calculating the 95% confidence intervals (CIs) around the relative risk. Areas under ROC curves (AUCs) (Hanley and McNeil for paired analysis and z statistics for unpaired analysis) and reading times (Wilcoxon signed rank test) were compared across the sessions, within each session and for the whole study. RESULTS The range of detection rates was 79 of 111 (.71 [95% CI: .61, .79]) to 91 of 111 (.82 [95% CI: .73, .88]). The range of false-positive rates was 17 of 111 (.15 [95% CI: .09, .23]) to 22 of 111 (.20 [95% CI: .12, .28]). All readers' AUCs rose from session 1 to session 4; this rise was significant (P < .05) for the non-CAD group. Only during session 1 was the CAD group AUC (.83) higher than the non-CAD group AUC (.54) (P < .05). Comparison of CAD and non-CAD reading times showed no significant difference for the whole study or during each session (P > .05). CONCLUSION The virtual dissection reading technique allows short learning curves, which may be improved by the concurrent use of CAD, without significant effect on average reading time.
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Affiliation(s)
- Danielle Hock
- Department of Medical Imaging, Clinique Saint-Joseph, Rue de Hesbaye, 75, 4000 Liège, Belgium.
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Juchems MS, Ernst AS, Brambs HJ, Aschoff AJ. Computer-aided detection in computer tomography colonography: a review. ACTA ACUST UNITED AC 2008; 2:487-95. [DOI: 10.1517/17530059.2.5.487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Carrascosa P, Capuñay C, López EM, Ulla M, Castiglioni R, Carrascosa J. Multidetector CT colonoscopy: evaluation of the perspective-filet view virtual colon dissection technique for the detection of elevated lesions. ACTA ACUST UNITED AC 2008; 32:582-8. [PMID: 17143581 DOI: 10.1007/s00261-006-9169-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND The purpose of our study was to determine the usefulness of a virtual computed tomography colon dissection visualization technique for the detection of polypoid lesions in comparison with conventional virtual colonoscopy analysis and optical colonoscopy. METHODS Twenty-three patients were evaluated with optical colonoscopy and computed tomography colonoscopy using 16-row MDCT on the same day. CT images were analyzed by the colon dissection workup with unfolded haustra visualization and also using the conventional virtual colonoscopy technique (axial images and endoluminal views). The CT analysis was performed by an experienced radiologist using both viewing methods in a randomized order and blinded to optical colonoscopy results. RESULTS Optical colonoscopy revealed 35 colonic lesions; 15 < 5 mm, 18 between 5-9 mm and 2 > 9 mm. For conventional virtual colonoscopy analysis the overall sensitivity was 86.67%; for the colon dissection visualization technique, the overall sensitivity was 82.86%. The average reading time for conventional virtual colonoscopy was 15 +/- 3 vs. 8 +/- 2 min for the colon dissection visualization technique. CONCLUSIONS Our results showed that there is a significant reduction in the reading time using the colon dissection visualization technique without detriment to the detection rate, that is, competitive to conventional virtual colonoscopy interpretation results.
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Affiliation(s)
- Patricia Carrascosa
- Department of Computed Tomography, Diagnóstico Maipú., Alsina 30, San Isidro (1642), Buenos Aires, Argentina.
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Uni- and bidirectional wide angle CT colonography: effect on missed areas, surface visualization, viewing time and polyp conspicuity. Eur Radiol 2008; 18:1910-7. [DOI: 10.1007/s00330-008-0969-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 01/17/2008] [Accepted: 03/06/2008] [Indexed: 01/16/2023]
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26
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[CT colonography: techniques of visualization and findings]. Radiologe 2008; 48:135-45. [PMID: 18210054 DOI: 10.1007/s00117-007-1604-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Evaluation and interpretation of CT colonography is based on both 2D and 3D techniques. The 2D techniques are popular mainly because the time needed for evaluation is short. The 3D techniques allow better definition than the 2D techniques, especially of polyps close to folds or at the base of a fold. The evaluation strategies generally accepted so far (primarily 2D, with 3D for problem cases, or vice versa) demand knowledge of both 2D and 3D techniques. Newer 3D visualization techniques help make it possible to acquire more complete and faster recording particularly of areas that are not easily accessible to endoscopic examination. These user-friendly developments are thus well suited to improving the detection and the security of detection of polyps. It must be remembered that experience and the knowledge of associated artifacts and the limitations they can impose on diagnosis are prime requirements for the implementation of such visualization techniques.
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Park SH, Yee J, Kim SH, Kim YH. Fundamental elements for successful performance of CT colonography (virtual colonoscopy). Korean J Radiol 2007; 8:264-75. [PMID: 17673837 PMCID: PMC2627155 DOI: 10.3348/kjr.2007.8.4.264] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
There are many factors affecting the successful performance of CT colonography (CTC). Adequate colonic cleansing and distention, the optimal CT technique and interpretation with using the newest CTC software by a trained reader will help ensure high accuracy for lesion detection. Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation. Automated carbon dioxide insufflation is more efficient and may be safer for colonic distention as compared to manual room air insufflation. CT scanning should use thin collimation of < or =3 mm with a reconstruction interval of < or =1.5 mm and a low radiation dose. There is not any one correct method for the interpretation of CTC; therefore, readers should be well-versed with both the primary 3D and 2D reviews. Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system. The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea.
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Affiliation(s)
- Seong Ho Park
- Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-2dong, Songpa-gu, 138-736 Seoul, Korea.
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Aschoff AJ, Ernst AS, Brambs HJ, Juchems MS. CT colonography: an update. Eur Radiol 2007; 18:429-37. [PMID: 17899101 DOI: 10.1007/s00330-007-0764-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 07/25/2007] [Accepted: 08/24/2007] [Indexed: 12/19/2022]
Abstract
Computed tomographic (CT) colonography (CTC)--also known as "virtual colonoscopy"--was first described more than a decade ago. As advancements in scanner technology and three-dimensional (3D) postprocessing helped develop this method to mature into a potential option in screening for colorectal cancer, the fundamentals of the examination remained the same. It is a minimally invasive, CT-based procedure that simulates conventional colonoscopy using 2D and 3D computerized reconstructions. The primary aim of CTC is the detection of colorectal polyps and carcinomas. However, studies reveal a wide performance variety in regard to polyp detection, especially for smaller polyps. This article reviews the available literature, discusses established indications as well as open issues and highlights potential future developments of CTC.
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Affiliation(s)
- Andrik J Aschoff
- Diagnostic and Interventional Radiology, University Hospitals of Ulm, Steinhoevelstr. 9, 89070, Ulm, Germany.
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Kim SH, Lee JM, Eun HW, Lee MW, Han JK, Lee JY, Choi BI. Two- versus Three-dimensional Colon Evaluation with Recently Developed Virtual Dissection Software for CT Colonography. Radiology 2007; 244:852-64. [PMID: 17709833 DOI: 10.1148/radiol.2443060934] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This retrospective study was institutional review board approved; the requirement for informed patient consent was waived. The purpose of this study was to retrospectively compare a two-dimensional (2D) data interpretation technique with a three-dimensional (3D) colon dissection technique in terms of interpretation time and sensitivity for colonic polyp detection, with colonoscopy as the reference standard. Ninety-six patients (56 men, 40 women; mean age, 54.8 years) underwent colonoscopy and multidetector computed tomographic (CT) colonography on the same day. Two radiologists independently analyzed the data on a per-polyp and per-patient basis. The sensitivity of both approaches was compared by using the McNemar test. The time required to interpret CT colonographic data with each technique was also assessed. Compared with the conventional 2D colonic polyp detection method, primary 3D interpretation with use of virtual dissection software for CT colonography revealed comparable per-polyp (77% and 69% for two readers) and per-patient (77% and 73% for two readers) sensitivities and comparable per-patient specificity (99% and 89% for two readers) for the detection of polyps 6 mm in diameter or larger and involved a shorter interpretation time.
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Affiliation(s)
- Se Hyung Kim
- Department of Radiology and Institute of Radiation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea
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Rockey DC, Barish M, Brill JV, Cash BD, Fletcher JG, Sharma P, Wani S, Wiersema MJ, Peterson LE, Conte J. Standards for gastroenterologists for performing and interpreting diagnostic computed tomographic colonography. Gastroenterology 2007; 133:1005-24. [PMID: 17678924 DOI: 10.1053/j.gastro.2007.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Don C Rockey
- University of Texas Southwestern Medical Center, Division of Digestive and Liver Diseases, Dallas, Texas, USA
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Glick S. Will 3D Virtual Dissection Display Prove to Be the Display Format for Reviewing CT Colonography Examinations? Radiology 2007; 244:629-30. [PMID: 17709819 DOI: 10.1148/radiol.2443070748] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In the study by Kim et al, primary two-dimensional (2D) search with a three-dimensional (3D) problem-solving technique was compared with a 3D virtual dissection technique, with use of two independent reviewers. The authors observed no significant difference (P>.05) in sensitivity or specificity between the two techniques for the detection of polyps 6 mm or larger, whereas the median review time with virtual dissection was significantly (P<.05) shorter. This may have implications for the application of computed tomographic (CT) colonography for screening the asymptomatic average-risk population.
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Affiliation(s)
- Seth Glick
- Department of Medical Imaging, Penn Presbyterian Medical Center, 39th and Market Streets, Philadelphia, PA 19104, USA.
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Johnson CD, Fletcher JG, MacCarty RL, Mandrekar JN, Harmsen WS, Limburg PJ, Wilson LA. Effect of Slice Thickness and Primary 2D Versus 3D Virtual Dissection on Colorectal Lesion Detection at CT Colonography in 452 Asymptomatic Adults. AJR Am J Roentgenol 2007; 189:672-80. [PMID: 17715116 DOI: 10.2214/ajr.07.2354] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE The objective of our study was to compare the performance of primary 3D search using 360 degree virtual dissection with primary 2D search using a 2.5- versus a 1.25-mm slice thickness. SUBJECTS AND METHODS Four hundred fifty-two asymptomatic patients underwent CT colonography (CTC) and colonoscopy. Examinations were reconstructed to 1.25- and 2.5-mm slice thicknesses and interpreted using primary 3D search (360 degree virtual dissection) and primary 2D search. Two of three experienced reviewers were randomly assigned to each case; 1,808 interpretations were performed. RESULTS There were 64 adenomas > or = 6 mm, 26 of which were large adenomas > or = 1 cm. For adenomas 6-9 mm in diameter, the area under the receiver operating characteristic curve (AUC) using 2.5-mm data sets was 0.66, 0.62, 0.90 and 0.78, 0.69, 0.67 for reviewers 1, 2, and 3, respectively, using primary 3D versus 2D search (p = not significant [NS]). For neoplasms > or = 10 mm, the AUC using 2.5-mm data sets was 0.74, 0.85, 0.89 and 0.66, 0.86, 0.92 for reviewers 1, 2, and 3 using primary 3D versus 2D search (p = NS). There was no significant difference using 1.25-mm collimation. Double review using both primary 3D and 2D search yielded sensitivities of 84% (16/19) and 95% (18/19) for large neoplasms (> or = 1 cm) using 2.5- and 1.25-mm data sets, respectively. Five of five (100%) adenocarcinomas were identified. The sensitivity of colonoscopy for large neoplasms was 77% (20/26) (20% [1/5] for adenocarcinoma). CONCLUSION No advantage exists for 1.25- or 2.5-mm slice thickness or for primary 3D versus 2D search at CTC. Double review using primary 3D (virtual dissection) and 2D search reduces interobserver variability and competes with colonoscopy for the detection of large lesions.
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Affiliation(s)
- C Daniel Johnson
- Department of Radiology, Mayo Clinic, 200 First St., SW, Rochester, MN 55905, USA
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Dachman AH, Lefere P, Gryspeerdt S, Morin M. CT colonography: visualization methods, interpretation, and pitfalls. Radiol Clin North Am 2007; 45:347-59. [PMID: 17502222 DOI: 10.1016/j.rcl.2007.03.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Virtual colonoscopy interpretation is improving rapidly with the development of efficient software using two-dimensional, three-dimensional (3D) endoluminal, and 3D novel views such as those that seem to cut the colon open and lay it flat for interpretation. Comparison of these various views, comparisons of supine and prone positioning, and comparisons of lung and soft tissue windows aid in the recognition of various pitfalls of interpretation.
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Affiliation(s)
- Abraham H Dachman
- Department of Radiology, MC2026, The University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60645, USA.
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34
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Cadi M. Place du coloscanner et de la coloscopie chez le sujet âgé. ONCOLOGIE 2007. [DOI: 10.1007/s10269-006-0589-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mang T, Graser A, Schima W, Maier A. CT colonography: techniques, indications, findings. Eur J Radiol 2007; 61:388-99. [PMID: 17224254 DOI: 10.1016/j.ejrad.2006.11.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2006] [Revised: 10/29/2006] [Accepted: 11/02/2006] [Indexed: 12/14/2022]
Abstract
Computed tomographic colonography (CTC) is a minimally invasive technique for imaging the entire colon. Based on a helical thin-section CT of the cleansed and air-distended colon, two-dimensional and three-dimensional projections are used for image interpretation. Several clinical improvements in patient preparation, technical advances in CT, and new developments in evaluation software have allowed CTC to develop into a powerful diagnostic tool. It is already well established as a reliable diagnostic tool in symptomatic patients. Many experts currently consider CTC a comparable alternative to conventional colonoscopy, although there is still debate about its sensitivity for the detection of colonic polyps in a screening population. This article summarizes the main indications, the current techniques in patient preparation, data acquisition and data analysis as well as imaging features for common benign and malignant colorectal lesions.
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Affiliation(s)
- Thomas Mang
- Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
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Abstract
Colorectal cancer remains a leading cancer killer worldwide. The disease is both curable and preventable, and yet the importance of widespread screening is only now starting to be appreciated. This article reviews the variety of diagnostic tests, imaging procedures and endoscopic examinations available to detect colorectal cancer and polyps in their early stage and also presents details on various screening options. The critical role of the radiologist is elaborated on including accurate assessment of the tumor extent within the bowel wall and beyond and the detection of lymph node and distant metastases. Staging with CT, MR imaging, endorectal ultrasound, and positron emission tomography are of paramount importance in determining the most appropriate therapy and the risk of tumor recurrence and overall prognosis.
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Affiliation(s)
- Marc J Gollub
- Department of Radiology, Weill Medical College of Cornell University, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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Silva AC, Wellnitz CV, Hara AK. Three-dimensional virtual dissection at CT colonography: unraveling the colon to search for lesions. Radiographics 2006; 26:1669-86. [PMID: 17102043 DOI: 10.1148/rg.266055199] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Computed tomographic (CT) colonography is a promising noninvasive examination for colorectal cancer screening; however, the optimal interpretation strategy remains undecided. Virtual dissection is an innovative technique whereby the three-dimensional (3D) model of the colon is virtually unrolled, sliced open, and displayed as a flat 3D rendering of the mucosal surface, similar to a gross pathologic specimen. This technique has the potential to reduce evaluation time by providing a more rapid 3D image assessment than is possible with an antegrade and retrograde 3D endoluminal fly-through. It may also ultimately improve accuracy by reducing blind spots present with 3D endoluminal displays and by reducing reader fatigue. A disadvantage of virtual dissection is the potential for distortion of colonic lesions and normal anatomy. To avoid potential pitfalls in image interpretation, the radiologist must be familiar with the unique appearance of the normal colon anatomy and of various pathologic findings when using virtual dissection with two-dimensional axial and 3D endoluminal CT colonographic image data sets.
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Affiliation(s)
- Alvin C Silva
- Department of Diagnostic Radiology, Mayo Clinic, 13400 E Shea Blvd, Scottsdale, AZ 85259, USA.
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Abstract
Published results to date have indicated a good per patient sensitivity of computed tomographic colonography (CTC) for colorectal cancer and for polyps measuring 10 mm or more together with a very good specificity. Sensitivity and specificity for polyps in the range of 6-10 mm are moderate. These results, however, can be achieved only with meticulous attention to technique including adequate colonic distention, and acquisition of supine and prone thin-section computed tomographic (CT) images. Moreover, there is a significant learning curve involved in the interpretation of CTC studies, with performance statistics improving with operator experience. Radiologists must be comfortable in reporting directly from workstation monitors and have access to and be familiar with software for multiplanar and endoluminal reconstructions. In addition to maximize polyp detection and minimize false positive results, reporting radiologists must have a working knowledge of normal colorectal anatomy and pathology on CTC and be familiar with potential pitfalls in interpretation. Besides the description of several possible causes for perceptive errors, also a literature search of perceptive errors in CTC is included in this paper.
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Affiliation(s)
- C Y Nio
- Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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van Gelder RE, Florie J, Nio CY, Jensch S, de Jager SW, Vos FM, Venema HW, Bartelsman JF, Reitsma JB, Bossuyt PMM, Laméris JS, Stoker J. A comparison of primary two- and three-dimensional methods to review CT colonography. Eur Radiol 2006; 17:1181-92. [PMID: 17119975 DOI: 10.1007/s00330-006-0487-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2006] [Revised: 08/28/2006] [Accepted: 09/28/2006] [Indexed: 11/29/2022]
Abstract
The aim of our study was to compare primary three-dimensional (3D) and primary two-dimensional (2D) review methods for CT colonography with regard to polyp detection and perceptive errors. CT colonography studies of 77 patients were read twice by three reviewers, first with a primary 3D method and then with a primary 2D method. Mean numbers of true and false positives, patient sensitivity and specificity and perceptive errors were calculated with colonoscopy as a reference standard. A perceptive error was made if a polyp was not detected by all reviewers. Mean sensitivity for large (> or = 10 mm) polyps for primary 3D and 2D review was 81% (14.7/18) and 70%(12.7/18), respectively (p-values > or = 0.25). Mean numbers of large false positives for primary 3D and 2D were 8.3 and 5.3, respectively. With primary 3D and 2D review 1 and 6 perceptive errors, respectively, were made in 18 large polyps (p = 0.06). For medium-sized (6-9 mm) polyps these values were for primary 3D and 2D, respectively: mean sensitivity: 67%(11.3/17) and 61%(10.3/17; p-values > or = 0.45), number of false positives: 33.3 and 15.6, and perceptive errors : 4 and 6 (p = 0.53). No significant differences were found in the detection of large and medium-sized polyps between primary 3D and 2D review.
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Affiliation(s)
- Rogier E van Gelder
- Department of Radiology, Academic Medical Center of the University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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Bowel preparation for CT-colonography: comparison of two different cleansing protocols. Eur J Radiol 2006; 60:460-4. [PMID: 17055683 DOI: 10.1016/j.ejrad.2006.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 08/04/2006] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Comparison of cleansing effects and colonic distension observed with two polyethyleneglycol-solution (PEG) containing bowel preparation techniques prior to CT-colonography (CTC). MATERIALS AND METHODS One hundred and three patients that received CTC in our institution were retrospectively evaluated. Fifty-one patients received preparation 1 (BP1; based on a GoLytely formulation+bisacodyl), 52 preparation 2 (BP2; based on a NuLytely formulation+bisacodyl). On multi-planar-reformatted (MPR) images, fluid residuals and colon distension were assessed in five colonic segments, from the ascending colon to the rectum. RESULTS On average, significantly (p<0.001) lower fluid residuals were assesses when using BP2 regardless of the patient position. In prone position, a significantly lower fluid level was observed in the sigmoid using bowel preparation 2. The average maximum diameter measured for the whole colon was 5.2+/-0.6 cm in prone position and 4.8+/-0.6 cm in the supine position in BP1 (p<0.01). In BP2 the average maximum diameter measured for the whole colon was 5.3+/-0.6 cm in prone position and 4.7+/-0.5 cm in supine position, respectively (p<0.001). CONCLUSION Overall, lower fluid residuals were scored using BP2. In both preparation groups we achieved better colonic distension in prone position. We were not able to distend the sigmoid better when insufflating air during patient repositioning.
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Pickhardt PJ, Taylor AJ, Gopal DV. Surface visualization at 3D endoluminal CT colonography: degree of coverage and implications for polyp detection. Gastroenterology 2006; 130:1582-7. [PMID: 16697721 DOI: 10.1053/j.gastro.2006.01.044] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Accepted: 01/11/2006] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Effective colonoscopic screening for polyps, whether by optical or virtual means, requires adequate visualization of the entire colonic surface. The purpose of this study was to assess prospectively the degree of surface coverage at 3-dimensional (3D) endoluminal computed tomography colonography (CTC) after retrograde fly-through, combined retrograde-antegrade fly-through, and review of remaining missed regions. METHODS The study group consisted of 223 asymptomatic adults (mean age, 57.8 +/- 7.2 y; 111 men, 112 women) undergoing primary CTC screening. CTC studies were interpreted by experienced readers using a primary 3D approach. The CTC software system that was used continually tracks the percentage of endoluminal surface visualized. The degree of coverage was assessed prospectively after retrograde and combined retrograde-antegrade navigation. The added effect of reviewing missed regions was also assessed prospectively. RESULTS The mean surface coverage after only retrograde 3D endoluminal fly-through from rectum to cecum was 76.6% +/- 4.8% (range, 63%-92%); coverage was 80% or less in 181 (81.2%) patients. Antegrade navigation back to the rectum increased the overall coverage to 94.1% +/- 2.3% (range, 84%-99%; P < .0001). A review of missed regions 300 mm(2) or larger increased coverage to 97.9% +/- 1.1% (range, 93%-99%; P < .0001) and added 21.4 +/- 11.4 seconds to the interpretation time (range, 3-67 s). CONCLUSIONS Combined bidirectional retrograde and antegrade 3D navigation, supplemented by rapid review of missed regions, effectively covers the entire evaluable surface at CTC. Unidirectional retrograde 3D fly-through typically excludes 20% or more of the endoluminal surface, which may provide insight into potential limitations at optical colonoscopy.
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Affiliation(s)
- Perry J Pickhardt
- Department of Radiology, University of Wisconsin Medical School, Madison, Wisconsin, USA.
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Silva AC, Hara AK, Leighton JA, Heppell JP. CT colonography with intravenous contrast material: varied appearances of colorectal carcinoma. Radiographics 2006; 25:1321-34. [PMID: 16160114 DOI: 10.1148/rg.255045184] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Computed tomographic (CT) colonography is a noninvasive, rapidly evolving technique that has been shown in some studies to be comparable with conventional colonoscopy for the screening of colorectal cancer. Because colorectal cancer has a widely varying appearance at both endoscopy and CT colonography, familiarity with the gamut of morphologic appearances can help improve interpretation of the results. The addition of intravenous contrast material to CT colonography can aid differentiation of true colonic masses from pseudolesions such as residual stool and improves the depiction of enhancing masses that might otherwise be obscured by residual colonic fluid. In contrast to staging of most other tumors, staging of colorectal carcinoma depends more on the depth of tumor invasion than on the size of the primary mass. The diverse appearances of colorectal cancers at two- and three-dimensional CT colonography include sessile, annular, ulcerated, necrotic, mucinous, invasive, and noninvasive lesions. Imaging pitfalls that can simulate or obscure neoplasms are retained fecal material or fluid, incomplete distention, and advanced diverticulosis.
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Affiliation(s)
- Alvin C Silva
- Department of Diagnostic Radiology, Mayo Clinic, 13400 E Shea Blvd, Scottsdale, AZ 85259, USA.
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Yasumoto T, Murakami T, Yamamoto H, Hori M, Iannaccone R, Kim T, Abe H, Kuwabara M, Yamasaki K, Kikkawa N, Arimoto H, Passariello R, Nakamura H. Assessment of Two 3D MDCT Colonography Protocols for Observation of Colorectal Polyps. AJR Am J Roentgenol 2006; 186:85-9. [PMID: 16357383 DOI: 10.2214/ajr.04.1727] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE The objective of our study was to assess the value of two-way interpretation (i.e., from rectum to cecum and vice versa) compared with one-way interpretation (i.e., from rectum to cecum only) in terms of polyp detection and interpretation time on MDCT colonography. MATERIALS AND METHODS Fifty consecutive patients underwent both CT colonography and conventional colonoscopy. Three radiologists independently analyzed the CT colonographic examinations of each patient using a primary 3D method. All examinations were analyzed using two techniques: navigation from rectum to cecum only (one-way) and navigation from rectum to cecum and vice versa (two-way). Sensitivity and positive predictive value were calculated on both a per-polyp basis and a per-patient basis. Alternative free-response receiver operating characteristic (ROC) curve analysis was estimated, and image interpretation time was documented. RESULTS One hundred fifty-five polyps were depicted in 45 patients by colonoscopy. The mean sensitivity of CT colonography for polyp detection with two-way (88.4%) was significantly superior to that with one-way (78.1%) (p < 0.01). The mean positive predictive value of each observer with one-way was 66.7%, whereas that with two-way was 65.8%. The mean area under the alternative free-response ROC curve (A(z) value) with two-way (0.827) was higher than that with one-way (0.816), but there was not a statistically significant difference. The average interpretation time of each observer with two-way (39 min) was statistically significantly longer than that with one-way (25 min) (p < 0.01). CONCLUSION When using a primary 3D interpretation technique at CT colonography, complete 3D navigation from rectum to cecum and from cecum to rectum is mandatory to maximize polyp detection. The image interpretation time for two-way interpretation is statistically significantly longer than that with one-way interpretation.
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Affiliation(s)
- Taku Yasumoto
- Department of Radiology, Suita Municipal Hospital, Suita, Osaka, Japan
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Abstract
Over the past decade, computed tomographic (CT) colonography (also known as virtual colonoscopy) has been used to investigate the colon for colorectal neoplasia. Numerous clinical and technical advances have allowed CT colonography to advance slowly from a research tool to a viable option for colorectal cancer screening. However, substantial controversy remains among radiologists, gastroenterologists, and other clinicians with regard to the current role of CT colonography in clinical practice. On the one hand, all agree there is much excitement about a noninvasive imaging examination that can reliably depict clinically important colorectal lesions. However, this is tempered by results from several recent studies that show the sensitivity of CT colonography may not be as great when performed and the images interpreted by radiologists without expertise and training. The potential to miss important lesions exists; moreover, if polyps cannot be differentiated from folds and residual fecal matter, unnecessary colonoscopy will be performed. In this review, current issues will be discussed regarding colon cancer and the established and reimbursed strategies to screen for it and the past, current, and potential future role of CT colonography.
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Affiliation(s)
- Michael Macari
- Department of Radiology, Division of Abdominal Imaging, NYU Medical Center, NYU School of Medicine, 560 First Ave, Suite HW 207, New York, NY 10016, USA.
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45
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Purkayastha S, Tekkis PP, Athanasiou T, Aziz O, Negus R, Gedroyc W, Darzi AW. Magnetic resonance colonography versus colonoscopy as a diagnostic investigation for colorectal cancer: a meta-analysis. Clin Radiol 2005; 60:980-9. [PMID: 16124980 DOI: 10.1016/j.crad.2005.04.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Revised: 03/30/2005] [Accepted: 04/14/2005] [Indexed: 01/16/2023]
Abstract
AIMS Magnetic resonance colonography (MRC) is emerging as a potential complementary investigation for the diagnosis of colorectal cancer (CRC) and also for benign pathology such as diverticular disease. A meta-analysis reporting the use of MRC is yet to be performed. The aim of this study was to evaluate the diagnostic accuracy of MRC compared with the gold-standard investigation, conventional colonoscopy (CC). METHODS A literature search was carried out to identify studies containing comparative data between MRC findings and CC findings. Quantitative meta-analysis for diagnostic tests was performed, which included the calculation of independent sensitivities, specificities, diagnostic odds ratios, the construction of summary receiver operating characteristic (SROC) curves, pooled analysis and sensitivity analysis. The study heterogeneity was evaluated by the Q-test using a random-effect model to accommodate the cluster of outcomes between individual studies. RESULTS In all, 8 comparative studies were identified, involving 563 patients. The calculated pooled sensitivity for all lesions was 75% (95% CI: 47% to 91%), the specificity was 96% (95% CI: 86% to 98%) and the area under the ROC curve was 90% (weighted). On sensitivity analysis, MRC had a better diagnostic accuracy for CRC than for polyps, with a sensitivity of 91% (95% CI: 97% to 91%), a specificity of 98% (95% CI: 66% to 99%) and an area under the ROC curve of 92%. There was no significant heterogeneity between the studies with regard to the diagnostic accuracy of MRC for CRC. CONCLUSION This meta-analysis suggests that MRC is an imaging technique with high discrimination for cases presenting with colorectal cancer. The exact diagnostic role of MRC needs to be clarified (e.g. suitable for an elderly person with suspected CRC). Further evaluation is necessary to refine its applicability and diagnostic accuracy in comparison with other imaging methods such as computed tomography colonography.
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Affiliation(s)
- S Purkayastha
- Department of Surgical Oncology, Imperial College of Science, Technology and Medicine, St Mary's Hospital, London, UK
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Sörstedt E, Persson A, Norén B, Björnlert U, Malcherek P, Axelsson M, Johansson J, Smedby O. Computed tomographic colonography: comparison of two workstations. Acta Radiol 2005; 46:671-8. [PMID: 16372685 DOI: 10.1080/02841850500223109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To compare two commercially available computed tomography (CT) colonography systems with respect to interobserver variability, the influence of level of expertise, and the gradual reduction of reviewing time for each system. MATERIAL AND METHODS Two residents and two radiologists using Siemens CTAPP Colography software and Viatronix V3D-Colon software reviewed supine and prone CT acquisitions from 24 patients in a primary 3D endoluminal view. The observers graded each case with respect to technical quality and diagnostic value, assessed the presence of pathology, and indicated the time spent on the viewing. RESULTS Significant differences were found in technical quality (P < 0.001) and diagnostic value (P<0.001) depending on which system was used, with higher scores for the Viatronix software. The agreement between specialists tended to be higher than that between residents (kappa=0.63 (0.30-0.95) vs. kappa=0.51 (0.21-0.81)), and the residents gave significantly (P < 0.001) higher scores of technical quality. However, the level of expertise had no significant impact on the assessments. We noted extensive variability in pathological lesions found by the different observers. The number of findings did not differ between workstations, but the viewers tended to report larger polyp sizes with the Viatronix software. The time needed for viewing decreased significantly from the first to the last examination viewed by each observer. CONCLUSION Both the evaluated systems present trustworthy images of the human colon, but in a primary 3D setting the Viatronix software is favored owing to the user-friendly interface, higher experienced technical quality, and better diagnostic value.
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Affiliation(s)
- E Sörstedt
- Center for Medical Image Science and Visualization, Linköping University, Sweden
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47
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Nicholson FB, Barro JL, Bartram CI, Dehmeshki J, Halligan S, Taylor S, Kamm MA. The role of CT colonography in colorectal cancer screening. Am J Gastroenterol 2005; 100:2315-23. [PMID: 16181386 DOI: 10.1111/j.1572-0241.2005.50391.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Computed tomographic colonography (CTC) is a relatively noninvasive technique for large bowel imaging that has the ability to detect colorectal neoplasia. Already well established as a reliable diagnostic tool in symptomatic patients who are unable to undergo complete colonoscopy, it is now being considered as a viable method for population screening. Advances in technique over the past 10 yr make this an attractive alternative, including reduced bowel preparation and stool tagging, three-dimensional (3D) image reconstruction, computer-aided detection software, and low-radiation dose protocols. CTC may be favored by patients compared to other available screening tests due to the ease of performance and comfort. Although published studies vary in relation to the sensitivity of this test for the detection of polyps, in the best hands a sensitivity of greater than 90% for detection of polyps at least 10 mm in diameter may be obtained. Although not yet endorsed for widespread use by major gastroenterological societies, CTC shows promise as a screening tool.
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48
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Abstract
Computed tomographic colonography (CTC, virtual colonoscopy) is an attractive modality with which to image the colon. Many different techniques are available; moreover, during the last several years, advances in hardware and software have been remarkable. Evidence to this date suggests that CTC has varying sensitivity for detection of large colonic lesions, largely dependent on technique and the method of study. A variety of issues related to CTC are reviewed, including evolution of CTC, sensitivity and specificity of CTC, patient experience, extracolonic lesions, advances in colon preparation, and training. It is clear that CTC has great promise, but also that many questions about its use remain to be answered.
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Affiliation(s)
- Don C Rockey
- Duke University Medical Center, Durham, NC 27710, USA.
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Spreng A, Netzer P, Mattich J, Dinkel HP, Vock P, Hoppe H. Importance of extracolonic findings at IV contrast medium-enhanced CT colonography versus those at non-enhanced CT colonography. Eur Radiol 2005; 15:2088-95. [PMID: 15965661 DOI: 10.1007/s00330-005-2798-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 04/24/2005] [Accepted: 04/29/2005] [Indexed: 12/27/2022]
Abstract
To compare the clinical importance of extracolonic findings at intravenous (IV) contrast-enhanced CT colonography versus those at non-enhanced CT colonography. IV contrast medium-enhanced (n=72) and non-enhanced (n=30) multidetector CT colonography was performed in 102 symptomatic patients followed by conventional colonoscopy on the same day. The impact of extracolonic findings on further work up and treatment was assessed by a review of patient records. Extracolonic findings were divided into two groups: either leading to further work up respectively having an impact on therapy or not. A total of 303 extracolonic findings were detected. Of those, 71% (215/303) were found on IV contrast-enhanced CT, and 29% (88/303) were found on non-enhanced CT colonography. The extracolonic findings in 25% (26/102) of all patients led to further work up or had an impact on therapy. Twenty-two of these patients underwent CT colonography with IV contrast enhancement, and four without. The percentage of extracolonic findings leading to further work up or having an impact on therapy was higher for IV contrast-enhanced (31%; 22/72) than for non-enhanced (13%; 4/30) CT scans (P=0.12). IV contrast-enhanced CT colonography produced more extracolonic findings than non-enhanced CT colonography. A substantially greater proportion of findings on IV contrast-enhanced CT colonography led to further work up and treatment than did non-enhanced CT colonography.
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Affiliation(s)
- Adrian Spreng
- Institute of Diagnostic Radiology, Inselspital, University of Bern, Freiburgstrasse 10, 3010, Bern, Switzerland
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Juchems MS, Fleiter TR, Pauls S, Schmidt SA, Brambs HJ, Aschoff AJ. CT colonography: comparison of a colon dissection display versus 3D endoluminal view for the detection of polyps. Eur Radiol 2005; 16:68-72. [PMID: 16402257 DOI: 10.1007/s00330-005-2805-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 04/15/2005] [Accepted: 05/03/2005] [Indexed: 02/08/2023]
Abstract
The purpose of this study was to compare sensitivity, specificity, and postprocessing time of a colon dissection approach to regular 3D-endoluminal workup of computed tomography (CT) colonography for the detection of polypoid lesions. Twenty-one patients who had received conventional colonoscopy after CT colonography were selected; 18 patients had either colon polyps or colon cancer and three had no findings. CT colonography was performed using a 4-channel multi-detector-row (MDR) CT in ten cases and a 16-channel MDR-CT in 11 cases. A blinded reader retrospectively evaluated all colonographies using both viewing methods in a randomized order. Thirty-seven polyps were identified by optical colonoscopy. An overall per-lesion sensitivity of 47.1% for lesions smaller than 5 mm, 56.3% for lesions between 5 mm and 10 mm, and 75.0% for lesion larger than 10 mm was calculated using the colon dissection approach. This compared to an overall per-lesion sensitivity of 35.3% (<5 mm), 81.5% (5-10 mm), and 100.0% (>10 mm) using the endoluminal view. The average time consumption for CT colonography evaluation with the colon dissection software was 10 min versus 38 min using the endoluminal view. A colon dissection approach may provide a significant time advantage for evaluation of CT colonography while obtaining a high sensitivity. It is especially superior in the detection of lesions smaller than 5 mm.
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Affiliation(s)
- Markus S Juchems
- Department for Diagnostic Radiology, University Hospital of Ulm, Steinhoevelstr. 9, 89075, Ulm, Germany.
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