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Chawla T, Hurrell C, Keough V, Lindquist CM, Mohammed MF, Samson C, Sugrue G, Walsh C. Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography. Can Assoc Radiol J 2024; 75:54-68. [PMID: 37411043 DOI: 10.1177/08465371231182975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/08/2023] Open
Abstract
Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.
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Affiliation(s)
- Tanya Chawla
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Casey Hurrell
- Canadian Association of Radiologists, Ottawa, Ontario, Canada
| | - Valerie Keough
- Department of Diagnostic Radiology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Chris M Lindquist
- Department of Radiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Mohammed F Mohammed
- Abdominal Radiology Section, Department of Radiology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Caroline Samson
- Département de Radiologie, Radio-oncologie et Médecine Nucléaire, Université de Montréal, Montreal, Quebec, Canada
| | - Gavin Sugrue
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Cynthia Walsh
- Department of Radiology, Radiation Oncology and Medical Physics, University of Ottawa, Ottawa, Ontario, Canada
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Grosu S, Wiemker R, An C, Obmann MM, Wong E, Yee J, Yeh BM. Comparison of the performance of conventional and spectral-based tagged stool cleansing algorithms at CT colonography. Eur Radiol 2022; 32:7936-7945. [PMID: 35486170 DOI: 10.1007/s00330-022-08831-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 03/15/2022] [Accepted: 04/20/2022] [Indexed: 01/03/2023]
Abstract
OBJECTIVES To compare the performance of conventional versus spectral-based electronic stool cleansing for iodine-tagged CT colonography (CTC) using a dual-layer spectral detector scanner. METHODS We retrospectively evaluated iodine contrast stool-tagged CTC scans of 30 consecutive patients (mean age: 69 ± 8 years) undergoing colorectal cancer screening obtained on a dual-layer spectral detector CT scanner. One reader identified locations of electronic cleansing artifacts (n = 229) on conventional and spectral cleansed images. Three additional independent readers evaluated these locations using a conventional cleansing algorithm (Intellispace Portal) and two experimental spectral cleansing algorithms (i.e., fully transparent and translucent tagged stool). For each cleansed image set, readers recorded the severity of over- and under-cleansing artifacts on a 5-point Likert scale (0 = none to 4 = severe) and readability compared to uncleansed images. Wilcoxon's signed-rank tests were used to assess artifact severity, type, and readability (worse, unchanged, or better). RESULTS Compared with conventional cleansing (66% score ≥ 2), the severity of overall cleansing artifacts was lower in transparent (60% score ≥ 2, p = 0.011) and translucent (50% score ≥ 2, p < 0.001) spectral cleansing. Under-cleansing artifact severity was lower in transparent (49% score ≥ 2, p < 0.001) and translucent (39% score ≥ 2, p < 0.001) spectral cleansing compared with conventional cleansing (60% score ≥ 2). Over-cleansing artifact severity was worse in transparent (17% score ≥ 2, p < 0.001) and translucent (14% score ≥ 2, p = 0.023) spectral cleansing compared with conventional cleansing (9% score ≥ 2). Overall readability was significantly improved in transparent (p < 0.001) and translucent (p < 0.001) spectral cleansing compared with conventional cleansing. CONCLUSIONS Spectral cleansing provided more robust electronic stool cleansing of iodine-tagged stool at CTC than conventional cleansing. KEY POINTS • Spectral-based electronic cleansing of tagged stool at CT colonography provides higher quality images with less perception of artifacts than does conventional cleansing. • Spectral-based electronic cleansing could potentially advance minimally cathartic approach for CT colonography. Further clinical trials are warranted.
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Affiliation(s)
- Sergio Grosu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA. .,Department of Radiology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany.
| | - Rafael Wiemker
- Philips Research Laboratories Hamburg, Röntgenstraße 24, 22335, Hamburg, Germany
| | - Chansik An
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA
| | - Markus M Obmann
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA.,Department of Radiology and Nuclear Imaging, University Hospital Basel, Petersgraben 4, CH - 4051, Basel, Switzerland
| | - Eddy Wong
- CT/AMI Clinical Science, Philips Healthcare, 100 Park Avenue, Orange Village, OH, 44122, USA
| | - Judy Yee
- Department of Radiology, Montefiore Medical Center, Albert Einstein College of Medicine, 111 E 210th Street, Bronx, NY, 10467-2401, USA
| | - Benjamin M Yeh
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA
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Adam SZ, Rabinowich A, Kessner R, Blachar A. Spectral CT of the abdomen: Where are we now? Insights Imaging 2021; 12:138. [PMID: 34580788 PMCID: PMC8476679 DOI: 10.1186/s13244-021-01082-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 08/16/2021] [Indexed: 12/14/2022] Open
Abstract
Spectral CT adds a new dimension to radiological evaluation, beyond assessment of anatomical abnormalities. Spectral data allows for detection of specific materials, improves image quality while at the same time reducing radiation doses and contrast media doses, and decreases the need for follow up evaluation of indeterminate lesions. We review the different acquisition techniques of spectral images, mainly dual-source, rapid kV switching and dual-layer detector, and discuss the main spectral results available. We also discuss the use of spectral imaging in abdominal pathologies, emphasizing the strengths and pitfalls of the technique and its main applications in general and in specific organs.
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Affiliation(s)
- Sharon Z Adam
- Department of Diagnostic Radiology, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906, Tel Aviv, Israel. .,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Aviad Rabinowich
- Department of Diagnostic Radiology, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906, Tel Aviv, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rivka Kessner
- Department of Diagnostic Radiology, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906, Tel Aviv, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Arye Blachar
- Department of Diagnostic Radiology, Tel Aviv Sourasky Medical Center, 6 Weizmann St., 6423906, Tel Aviv, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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4
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Obmann MM, An C, Schaefer A, Sun Y, Wang ZJ, Yee J, Yeh BM. Improved Sensitivity and Reader Confidence in CT Colonography Using Dual-Layer Spectral CT: A Phantom Study. Radiology 2020; 297:99-107. [PMID: 32720868 DOI: 10.1148/radiol.2020200032] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Limited cathartic preparations for CT colonography with fecal tagging can improve patient comfort but may result in nondiagnostic examinations from poorly tagged stool. Dual-energy CT may overcome this limitation by improving the conspicuity of the contrast agent, but more data are needed. Purpose To investigate whether dual-energy CT improves polyp detection in CT colonography compared with conventional CT at different fecal tagging levels in vitro. Materials and Methods In this HIPAA-compliant study, between December 2017 and August 2019, a colon phantom 30 cm in diameter containing 60 polyps of different shapes (spherical, ellipsoid, flat) and size groups (5-9 mm, 11-15 mm) was constructed and serially filled with simulated feces tagged with four different iodine concentrations (1.26, 2.45, 4.88, and 21.00 mg of iodine per milliliter), then it was scanned with dual-energy CT with and without an outer fat ring to simulate large body size (total diameter, 42 cm). Two readers independently reviewed conventional 120-kVp CT and 40-keV monoenergetic dual-energy CT images to record the presence of polyps and confidence (three-point scale.) Generalized estimating equations were used for sensitivity comparisons between conventional CT and dual-energy CT, and a Wilcoxon signed-rank test was used for reader confidence. Results Dual-energy CT had higher overall sensitivity for polyp detection than conventional CT (58.8%; 95% confidence interval [CI]: 49.7%, 67.3%; 564 of 960 polyps vs 42.1%; 95% CI: 32.1%, 52.8%; 404 of 960 polyps; P < .001), including with the fat ring (48% and 31%, P < .001). Reader confidence improved with dual-energy CT compared with conventional images on all tagging levels (P < .001). Interrater agreement was substantial (κ = 0.74; 95% CI: 0.70, 0.77). Conclusion Compared with conventional 120-kVp CT, dual-energy CT improved polyp detection and reader confidence in a dedicated dual-energy CT colonography phantom, especially with suboptimal fecal tagging. © RSNA, 2020.
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Affiliation(s)
- Markus M Obmann
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94117 (M.M.O., C.A., A.S., Y.S., Z.J.W., B.M.Y.); and Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY (J.Y.)
| | - Chansik An
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94117 (M.M.O., C.A., A.S., Y.S., Z.J.W., B.M.Y.); and Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY (J.Y.)
| | - Amanda Schaefer
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94117 (M.M.O., C.A., A.S., Y.S., Z.J.W., B.M.Y.); and Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY (J.Y.)
| | - Yuxin Sun
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94117 (M.M.O., C.A., A.S., Y.S., Z.J.W., B.M.Y.); and Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY (J.Y.)
| | - Zhen J Wang
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94117 (M.M.O., C.A., A.S., Y.S., Z.J.W., B.M.Y.); and Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY (J.Y.)
| | - Judy Yee
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94117 (M.M.O., C.A., A.S., Y.S., Z.J.W., B.M.Y.); and Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY (J.Y.)
| | - Benjamin M Yeh
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94117 (M.M.O., C.A., A.S., Y.S., Z.J.W., B.M.Y.); and Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, New York, NY (J.Y.)
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Tachibana R, Näppi JJ, Ota J, Kohlhase N, Hironaka T, Kim SH, Regge D, Yoshida H. Deep Learning Electronic Cleansing for Single- and Dual-Energy CT Colonography. Radiographics 2018; 38:2034-2050. [PMID: 30422761 PMCID: PMC6276077 DOI: 10.1148/rg.2018170173] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 04/15/2018] [Accepted: 04/26/2018] [Indexed: 12/22/2022]
Abstract
Electronic cleansing (EC) is used for computational removal of residual feces and fluid tagged with an orally administered contrast agent on CT colonographic images to improve the visibility of polyps during virtual endoscopic "fly-through" reading. A recent trend in CT colonography is to perform a low-dose CT scanning protocol with the patient having undergone reduced- or noncathartic bowel preparation. Although several EC schemes exist, they have been developed for use with cathartic bowel preparation and high-radiation-dose CT, and thus, at a low dose with noncathartic bowel preparation, they tend to generate cleansing artifacts that distract and mislead readers. Deep learning can be used for improvement of the image quality with EC at CT colonography. Deep learning EC can produce substantially fewer cleansing artifacts at dual-energy than at single-energy CT colonography, because the dual-energy information can be used to identify relevant material in the colon more precisely than is possible with the single x-ray attenuation value. Because the number of annotated training images is limited at CT colonography, transfer learning can be used for appropriate training of deep learning algorithms. The purposes of this article are to review the causes of cleansing artifacts that distract and mislead readers in conventional EC schemes, to describe the applications of deep learning and dual-energy CT colonography to EC of the colon, and to demonstrate the improvements in image quality with EC and deep learning at single-energy and dual-energy CT colonography with noncathartic bowel preparation. ©RSNA, 2018.
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Affiliation(s)
| | | | | | | | - Toru Hironaka
- From the 3D Imaging Research Lab, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon St, Suite 400C, Boston, MA 02114 (R.T., J.J.N., N.K., T.H., H.Y.); Department of Information Science and Technology, National Institute of Technology, Oshima College, Yamaguchi, Japan (R.T.); Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan (J.O.); Department of Medical Physics, University of Applied Sciences Giessen, Giessen, Germany (N.K.); Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea (S.H.K.); Department of Surgical Sciences, University of Torino, Turin, Italy (D.R.); and Candiolo Cancer Institute, Fondazione del Piemonte per l’Oncologia–Istituto di Ricovero e Cura a Carattere Scientifico (FPO-IRCCS), Candiolo, Turin, Italy (D.R.)
| | - Se Hyung Kim
- From the 3D Imaging Research Lab, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon St, Suite 400C, Boston, MA 02114 (R.T., J.J.N., N.K., T.H., H.Y.); Department of Information Science and Technology, National Institute of Technology, Oshima College, Yamaguchi, Japan (R.T.); Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan (J.O.); Department of Medical Physics, University of Applied Sciences Giessen, Giessen, Germany (N.K.); Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea (S.H.K.); Department of Surgical Sciences, University of Torino, Turin, Italy (D.R.); and Candiolo Cancer Institute, Fondazione del Piemonte per l’Oncologia–Istituto di Ricovero e Cura a Carattere Scientifico (FPO-IRCCS), Candiolo, Turin, Italy (D.R.)
| | - Daniele Regge
- From the 3D Imaging Research Lab, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon St, Suite 400C, Boston, MA 02114 (R.T., J.J.N., N.K., T.H., H.Y.); Department of Information Science and Technology, National Institute of Technology, Oshima College, Yamaguchi, Japan (R.T.); Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan (J.O.); Department of Medical Physics, University of Applied Sciences Giessen, Giessen, Germany (N.K.); Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea (S.H.K.); Department of Surgical Sciences, University of Torino, Turin, Italy (D.R.); and Candiolo Cancer Institute, Fondazione del Piemonte per l’Oncologia–Istituto di Ricovero e Cura a Carattere Scientifico (FPO-IRCCS), Candiolo, Turin, Italy (D.R.)
| | - Hiroyuki Yoshida
- From the 3D Imaging Research Lab, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon St, Suite 400C, Boston, MA 02114 (R.T., J.J.N., N.K., T.H., H.Y.); Department of Information Science and Technology, National Institute of Technology, Oshima College, Yamaguchi, Japan (R.T.); Department of Medical Physics and Engineering, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan (J.O.); Department of Medical Physics, University of Applied Sciences Giessen, Giessen, Germany (N.K.); Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea (S.H.K.); Department of Surgical Sciences, University of Torino, Turin, Italy (D.R.); and Candiolo Cancer Institute, Fondazione del Piemonte per l’Oncologia–Istituto di Ricovero e Cura a Carattere Scientifico (FPO-IRCCS), Candiolo, Turin, Italy (D.R.)
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Yeh BM, Obmann MM, Westphalen AC, Ohliger MA, Yee J, Sun Y, Wang ZJ. Dual Energy Computed Tomography Scans of the Bowel: Benefits, Pitfalls, and Future Directions. Radiol Clin North Am 2018; 56:805-819. [PMID: 30119775 DOI: 10.1016/j.rcl.2018.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Current computed tomography bowel imaging is challenging given the variable distension, content, and location of the bowel, the different appearance of tumors within and adjacent to bowel, and peristaltic artifacts. Published data remain sparse. Derangements in enhancement may be highlighted, image artifacts reduced, and radiation dose from multiphase scans minimized. This modality is suited for imaging bowel tumor detection and characterization, gastrointestinal bleeding, and bowel inflammation, and ischemia. Experimental results on computed tomography colonography and novel bowel contrast material offer hope for major improvements in bowel interrogation. It is likely to become increasingly valuable for bowel-related disease diagnosis and monitoring.
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Affiliation(s)
- Benjamin M Yeh
- UCSF Department of Radiology, 505 Parnassus Avenue Box 0628, San Francisco, CA 94143-0628, USA.
| | - Markus M Obmann
- UCSF Department of Radiology, 505 Parnassus Avenue Box 0628, San Francisco, CA 94143-0628, USA
| | - Antonio C Westphalen
- UCSF Department of Radiology, 505 Parnassus Avenue Box 0628, San Francisco, CA 94143-0628, USA
| | - Michael A Ohliger
- UCSF Department of Radiology, 505 Parnassus Avenue Box 0628, San Francisco, CA 94143-0628, USA
| | - Judy Yee
- Montefiore Department of Radiology, New York, NY, USA; Montefiore Department of Radiology, Montefiore Hospital, 111 East 210th Street, Bronx, NY 10467, USA
| | - Yuxin Sun
- UCSF Department of Radiology, 505 Parnassus Avenue Box 0628, San Francisco, CA 94143-0628, USA
| | - Zhen J Wang
- UCSF Department of Radiology, 505 Parnassus Avenue Box 0628, San Francisco, CA 94143-0628, USA
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Özdeniz İ, İdilman İS, Köklü S, Hamaloğlu E, Özmen M, Akata D, Karçaaltıncaba M. Dual-energy CT characteristics of colon and rectal cancer allows differentiation from stool by dual-source CT. Diagn Interv Radiol 2018; 23:251-256. [PMID: 28440784 DOI: 10.5152/dir.2017.16225] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE We aimed to determine dual-energy computed tomography (DECT) characteristics of colorectal cancer and investigate effectiveness of DECT method in differentiating tumor from stool in patients with colorectal cancer. METHODS Fifty consecutive patients with colorectal tumors were enrolled. Staging was performed by DECT (80-140 kV) using dual-source CT after rectal air insufflation and without bowel preparation. Both visual and quantitative analyses were performed at 80 kV and 140 kV, on iodine map and virtual noncontrast (VNC) images. RESULTS All colorectal tumors had homogeneous pattern on iodine map. Stools demonstrated heterogeneous pattern in 86% (43/50) and homogeneous pattern in 14% (7/50) on iodine maps and were less visible on VNC images. Median density of tumors was 54 HU (18-100 HU) on iodine map and 28 HU (11-56 HU) on VNC images. Median density of stool was 36.5 HU (8-165 HU) on iodine map and -135.5 HU (-438 HU to -13 HU) on VNC images. The density of stools was significantly lower than tumors on both iodine map and VNC images (P < 0.001). The cutoff point of density measurement on VNC images was -1 HU with area under the curve of 1 and a sensitivity and specificity of 100%. CONCLUSION Density or visual analysis of iodine map and VNC DECT images allow accurate differentiation of tumor from stool.
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Affiliation(s)
- İlknur Özdeniz
- Department of Radiology, Hacettepe University School of Medicine, Ankara, Turkey.
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Sun K, Han R, Han Y, Shi X, Hu J, Lu B. Accuracy of Combined Computed Tomography Colonography and Dual Energy Iiodine Map Imaging for Detecting Colorectal masses using High-pitch Dual-source CT. Sci Rep 2018; 8:3790. [PMID: 29491380 PMCID: PMC5830575 DOI: 10.1038/s41598-018-22188-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/19/2018] [Indexed: 02/07/2023] Open
Abstract
To evaluate the diagnostic accuracy of combined computed tomography colonography (CTC) and dual-energy iodine map imaging for detecting colorectal masses using high-pitch dual-source CT, compared with optical colonography (OC) and histopathologic findings. Twenty-eight consecutive patients were prospectively enrolled in this study. All patients were underwent contrast-enhanced CTC acquisition using dual-energy mode and OC and pathologic examination. The size of the space-occupied mass, the CT value after contrast enhancement, and the iodine value were measured and statistically compared. The sensitivity, specificity, accuracy rate, and positive predictive and negative predictive values of dual-energy contrast-enhanced CTC were calculated and compared between conventional CTC and dual-energy iodine images. The iodine value of stool was significantly lower than the colonic neoplasia (P < 0.01). The sensitivity of conventional CTC was 95.6% (95% CI = 77.9%–99.2%), combined CTC and dual-energy iodine maps imaging was 95.6% (95% CI = 77.9%–99.2%). The specificity of the two methods was 42.8% (95% CI = 15.4%–93.5%) and 100% (95% CI = 47.9%–100%; P = 0.02), respectively. Compared with optical colonography and histopathology, combined CTC and dual-energy iodine maps imaging can distinguish stool and colonic neoplasia, distinguish between benign and malignant tumors initially and improve the diagnostic accuracy of CTC for colorectal cancer screening.
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Affiliation(s)
- Kai Sun
- Department of Radiology, Baotou Central Hospital, Baotou, 014040, China.,Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, People's Republic of China
| | - Ruijuan Han
- Department of Cardiology, Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Yang Han
- Department of Radiology, Baotou Central Hospital, Baotou, 014040, China
| | - Xuesen Shi
- Department of Gastroenterology, Baotou Central Hospital, Baotou, 014040, China
| | - Jiang Hu
- Department of of Surgery, Baotou Central Hospital, Baotou, 014040, China.
| | - Bin Lu
- Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, People's Republic of China.
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White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 4: Abdominal and Pelvic Applications. J Comput Assist Tomogr 2017; 41:8-14. [PMID: 27824670 DOI: 10.1097/rct.0000000000000546] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This is the fourth of a series of 4 white papers that represent expert consensus documents developed by the Society of Computed Body Tomography and Magnetic Resonance through its task force on dual-energy computed tomography. This article, part 4, discusses DECT for abdominal and pelvic applications and, at the end of each, will offer our consensus opinions on the current clinical utility of the application and opportunities for further research.
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10
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Gabbai M, Leichter I, Mahgerefteh S, Sosna J. Spectral material characterization with dual-energy CT: comparison of commercial and investigative technologies in phantoms. Acta Radiol 2015; 56:960-9. [PMID: 25182803 DOI: 10.1177/0284185114545150] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/01/2014] [Indexed: 11/16/2022]
Abstract
BACKGROUND Dual-energy computed tomography (DECT) enables tissue discrimination based on the X-ray attenuations at different photon energies emitted by the tube. The spectral dependencies of net X-ray attenuation can be analyzed and used to characterize specific materials. PURPOSE To evaluate the capability of DECT to characterize and differentiate high-density materials, using spectral analysis. MATERIAL AND METHODS Images of phantoms containing iodine, barium, gadolinium, and calcium solutions in five concentrations were obtained from three DECT scanners and with sequential scanning at different kV values from three conventional MDCT devices. DECT studies were performed with commercial dual-source and rapid kV-switching systems, and a spectral-detector CT (SDCT) prototype based on dual-layer detector technology. Spectral maps describing Hounsfield Units (HU) in low- versus high-energy images were calculated and characterizing curves for all materials were compared. RESULTS Spectral low- to- high energy maps yielded linear curves (R(2) = 0.98-0.999) with increasing slopes for calcium, gadolinium, barium, and iodine, respectively. Slope differences between all material pairs were highest (reaching 45%) for DECT with dual-source (140/80 kV) and rapid kV-switching (60/80 keV), reaching statistical significance (P < 0.05) with most techniques. Slope differences between all material pairs for sequential scanning were lower (reaching 32%). Slope differences lacked statistical significance for iodine-barium with two sequential-acquisition techniques and the dual-source DECT scanner, and the calcium-gadolium pair with the dual-source scanner. CONCLUSION All designated techniques for dual-energy scanning provide robust and material-specific spectral characterization and differentiation of barium, iodine, calcium, and gadolinium, though to varying degrees.
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Affiliation(s)
- Michal Gabbai
- Department of Radiology, Hadassah–Hebrew University Medical Center, Jerusalem, Israel
| | - Isaac Leichter
- Department of Radiology, Hadassah–Hebrew University Medical Center, Jerusalem, Israel
- Department of Applied Physics, Lev Academic Center, Jerusalem, Israel
| | - Samuel Mahgerefteh
- Department of Radiology, Hadassah–Hebrew University Medical Center, Jerusalem, Israel
| | - Jacob Sosna
- Department of Radiology, Hadassah–Hebrew University Medical Center, Jerusalem, Israel
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard School of Medicine, Boston, MA, USA
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Tachibana R, Näppi JJ, Kim SH, Yoshida H. Electronic cleansing for dual-energy CT colonography based on material decomposition and virtual monochromatic imaging. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2015; 9414:94140Q. [PMID: 25844029 DOI: 10.1117/12.2082375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
CT colonography (CTC) uses orally administered fecal-tagging agents to enhance retained fluid and feces that would otherwise obscure or imitate polyps on CTC images. To visualize the complete region of colon without residual materials, electronic cleansing (EC) can be used to perform virtual subtraction of the tagged materials from CTC images. However, current EC methods produce subtraction artifacts and they can fail to subtract unclearly tagged feces. We developed a novel multi-material EC (MUMA-EC) method that uses dual-energy CTC (DE-CTC) and machine-learning methods to improve the performance of EC. In our method, material decomposition is performed to calculate water-iodine decomposition images and virtual monochromatic (VIM) images. Using the images, a random forest classifier is used to label the regions of lumen air, soft tissue, fecal tagging, and their partial-volume boundaries. The electronically cleansed images are synthesized from the multi-material and VIM image volumes. For pilot evaluation, we acquired the clinical DE-CTC data of 7 patients. Preliminary results suggest that the proposed MUMA-EC method is effective and that it minimizes the three types of image artifacts that were present in previous EC methods.
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Affiliation(s)
- Rie Tachibana
- 3D Imaging Research, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon Street, Suite 400C, Boston, MA 02114, USA
| | - Janne J Näppi
- 3D Imaging Research, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon Street, Suite 400C, Boston, MA 02114, USA
| | - Se Hyung Kim
- Seoul National University Hospital, 101 Daehangno, Chongno-gu, Seoul 110-744, Republic of Korea
| | - Hiroyuki Yoshida
- 3D Imaging Research, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon Street, Suite 400C, Boston, MA 02114, USA
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Cai W, Lee JG, Zhang D, Kim SH, Zalis M, Yoshida H. Electronic cleansing in fecal-tagging dual-energy CT colonography based on material decomposition and virtual colon tagging. IEEE Trans Biomed Eng 2014; 62:754-65. [PMID: 25350911 DOI: 10.1109/tbme.2014.2364837] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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 study. Our results demonstrated that our VCT-EC scheme may provide a significant reduction of EC artifacts.
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Tachibana R, Näppi JJ, Yoshida H. Application of Pseudo-enhancement Correction to Virtual Monochromatic CT Colonography. ABDOMINAL IMAGING : COMPUTATIONAL AND CLINICAL APPLICATIONS : 6TH INTERNATIONAL WORKSHOP, ABDI 2014, HELD IN CONJUNCTION WITH MICCAI 2014, CAMBRIDGE, MA, USA, SEPTEMBER 14, 2014. ABDI (WORKSHOP) (6TH : 2014 : CAMBRIDGE, MASS.) 2014; 8676:169-178. [PMID: 26236781 DOI: 10.1007/978-3-319-13692-9_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In CT colonography, orally administered positive-contrast fecal-tagging agents are used for differentiating residual fluid and feces from true lesions. However, the presence of high-density tagging agent in the colon can introduce erroneous artifacts, such as local pseudo-enhancement and beam-hardening, on the reconstructed CT images, thereby complicating reliable detection of soft-tissue lesions. In dual-energy CT colonography, such image artifacts can be reduced by the calculation of virtual monochromatic CT images, which provide more accurate quantitative attenuation measurements than conventional single-energy CT colonography. In practice, however, virtual monochromatic images may still contain some pseudo-enhancement artifacts, and efforts to minimize radiation dose may enhance such artifacts. In this study, we evaluated the effect of image-based pseudo-enhancement post-correction on virtual monochromatic images in standard-dose and low-dose dual-energy CT colonography. The mean CT values of the virtual monochromatic standard-dose CT images of 51 polyps and those of the virtual monochromatic low-dose CT images of 20 polyps were measured without and with the pseudo-enhancement correction. Statistically significant differences were observed between uncorrected and pseudo-enhancement-corrected images of polyps covered by fecal tagging in standard-dose CT (p < 0.001) and in low-dose CT (p < 0.05). The results indicate that image-based pseudo-enhancement post-correction can be useful for optimizing the performance of image-processing applications in virtual monochromatic CT colonography.
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Del Gaizo AJ, Silva AC, Hara AK. The utility of dual-energy computed tomography in abdominal imaging. APPLIED RADIOLOGY 2014. [DOI: 10.37549/ar2048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Linguraru MG, Panjwani N, Fletcher JG, Summers RM. Automated image-based colon cleansing for laxative-free CT colonography computer-aided polyp detection. Med Phys 2012; 38:6633-42. [PMID: 22149845 DOI: 10.1118/1.3662918] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To evaluate the performance of a computer-aided detection (CAD) system for detecting colonic polyps at noncathartic computed tomography colonography (CTC) in conjunction with an automated image-based colon cleansing algorithm. METHODS An automated colon cleansing algorithm was designed to detect and subtract tagged-stool, accounting for heterogeneity and poor tagging, to be used in conjunction with a colon CAD system. The method is locally adaptive and combines intensity, shape, and texture analysis with probabilistic optimization. CTC data from cathartic-free bowel preparation were acquired for testing and training the parameters. Patients underwent various colonic preparations with barium or Gastroview in divided doses over 48 h before scanning. No laxatives were administered and no dietary modifications were required. Cases were selected from a polyp-enriched cohort and included scans in which at least 90% of the solid stool was visually estimated to be tagged and each colonic segment was distended in either the prone or supine view. The CAD system was run comparatively with and without the stool subtraction algorithm. RESULTS The dataset comprised 38 CTC scans from prone and/or supine scans of 19 patients containing 44 polyps larger than 10 mm (22 unique polyps, if matched between prone and supine scans). The results are robust on fine details around folds, thin-stool linings on the colonic wall, near polyps and in large fluid/stool pools. The sensitivity of the CAD system is 70.5% per polyp at a rate of 5.75 false positives/scan without using the stool subtraction module. This detection improved significantly (p = 0.009) after automated colon cleansing on cathartic-free data to 86.4% true positive rate at 5.75 false positives/scan. CONCLUSIONS An automated image-based colon cleansing algorithm designed to overcome the challenges of the noncathartic colon significantly improves the sensitivity of colon CAD by approximately 15%.
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Affiliation(s)
- Marius George Linguraru
- Imaging Biomarkers and Computer-Aided Diagnosis Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, 10 Center Drive, Bethesda, Maryland 20892, USA.
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Boellaard TN, de Haan MC, Venema HW, Stoker J. Colon distension and scan protocol for CT-colonography: an overview. Eur J Radiol 2011; 82:1144-58. [PMID: 22154604 DOI: 10.1016/j.ejrad.2011.10.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 10/31/2011] [Indexed: 12/18/2022]
Abstract
This article reviews two important aspects of CT-colonography, namely colonic distension and scan parameters. Adequate distension should be obtained to visualize the complete colonic lumen and optimal scan parameters should be used to prevent unnecessary radiation burden. For optimal distension, automatic carbon dioxide insufflation should be performed, preferably via a thin, flexible catheter. Hyoscine butylbromide is - when available - the preferred spasmolytic agent because of the positive effect on insufflation and pain/burden and its low costs. Scans in two positions are required for adequate distension and high polyp sensitivity and decubitus position may be used as an alternative for patients unable to lie in prone position. The great intrinsic contrast between air or tagging and polyps allows the use of low radiation dose. Low-dose protocol without intravenous contrast should be used when extracolonic findings are deemed unimportant. In patients suspected for colorectal cancer, normal abdominal CT scan protocols and intravenous contrast should be used in supine position for the evaluation of extracolonic findings. Dose reduction can be obtained by lowering the tube current and/or voltage. Tube current modulation reduces the radiation dose (except in obese patients), and should be used when available. Iterative reconstructions is a promising dose reducing tool and dual-energy CT is currently evaluated for its applications in CT-colonography. This review also provides our institution's insufflation procedure and scan parameters.
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Affiliation(s)
- Thierry N Boellaard
- Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam, The Netherlands.
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Decreased-Purgation CT Colonography: State of the Art. CURRENT COLORECTAL CANCER REPORTS 2011. [DOI: 10.1007/s11888-010-0085-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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