CT colonography: comparison of a colon dissection display versus 3D endoluminal view for the detection of polyps

International Nuclear Information System (INIS)

Juchems, Markus S.; Pauls, Sandra; Brambs, Hans-Juergen; Aschoff, Andrik J.; Fleiter, Thorsten R.; Schmidt, Stefan A.

2006-01-01

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% ( 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. (orig.)

Reducing image noise in computed tomography (CT) colonography: effect of an integrated circuit CT detector.

Science.gov (United States)

Liu, Yu; Leng, Shuai; Michalak, Gregory J; Vrieze, Thomas J; Duan, Xinhui; Qu, Mingliang; Shiung, Maria M; McCollough, Cynthia H; Fletcher, Joel G

2014-01-01

To investigate whether the integrated circuit (IC) detector results in reduced noise in computed tomography (CT) colonography (CTC). Three hundred sixty-six consecutive patients underwent clinically indicated CTC using the same CT scanner system, except for a difference in CT detectors (IC or conventional). Image noise, patient size, and scanner radiation output (volume CT dose index) were quantitatively compared between patient cohorts using each detector system, with separate comparisons for the abdomen and pelvis. For the abdomen and pelvis, despite significantly larger patient sizes in the IC detector cohort (both P 0.18). Based on the observed image noise reduction, radiation dose could alternatively be reduced by approximately 20% to result in similar levels of image noise. Computed tomography colonography images acquired using the IC detector had significantly lower noise than images acquired using the conventional detector. This noise reduction can permit further radiation dose reduction in CTC.

Bowel wall visualisation at CT colonography

International Nuclear Information System (INIS)

Svensson, M.H.; Hellstroem, M.; Svensson, E.

2002-01-01

Purpose: To evaluate the quality of bowel wall visualisation at CT colonography and the impact of examination in the supine and prone positions. Material and Methods: After bowel preparation, 111 patients underwent CT colonography. Air distension, degree of fluid redistribution with change in body position (supine and prone), influence of residual stool on bowel wall assessability, and quality of overall colon visualisation were evaluated using scales. Results: Thirty of 110 patients (27%) had complete overall visualisation of the colon wall and 52 (47%) had subtotal visualisation of a limited part of the colon. The entire colon was more often air-filled in the prone position (46%) than in the supine position (18%). Joint review of supine and prone data showed that for all colon segments, except the sigmoid (86%), 95% of the patients had complete air filling. All patients had residual fluid. In 75% to 99%, depending on segment, fluid did not interfere with the bowel wall visualisation in the combined evaluation of supine and prone data sets. Thirty-one patients had residual stool with potential negative influence on polyp detection. Conclusions: The colon wall was completely, or almost completely, visualised in 75% of the patients, and examination in the supine and prone positions was necessary for complete visualisation

CT colonography: Techniques, indications, findings

International Nuclear Information System (INIS)

Mang, Thomas; Graser, Anno; Schima, Wolfgang; Maier, Andrea

2007-01-01

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

Comprehensive Assessment of Osteoporosis and Bone Fragility with CT Colonography

Science.gov (United States)

Murthy, Naveen S.; Khosla, Sundeep; Clarke, Bart L.; Bruining, David H.; Kopperdahl, David L.; Lee, David C.; Keaveny, Tony M.

2016-01-01

Purpose To evaluate the ability of additional analysis of computed tomographic (CT) colonography images to provide a comprehensive osteoporosis assessment. Materials and Methods This Health Insurance Portability and Accountability Act–compliant study was approved by our institutional review board with a waiver of informed consent. Diagnosis of osteoporosis and assessment of fracture risk were compared between biomechanical CT analysis and dual-energy x-ray absorptiometry (DXA) in 136 women (age range, 43–92 years), each of whom underwent CT colonography and DXA within a 6-month period (between January 2008 and April 2010). Blinded to the DXA data, biomechanical CT analysis was retrospectively applied to CT images by using phantomless calibration and finite element analysis to measure bone mineral density and bone strength at the hip and spine. Regression, Bland-Altman, and reclassification analyses and paired t tests were used to compare results. Results For bone mineral density T scores at the femoral neck, biomechanical CT analysis was highly correlated (R2 = 0.84) with DXA, did not differ from DXA (P = .15, paired t test), and was able to identify osteoporosis (as defined by DXA), with 100% sensitivity in eight of eight patients (95% confidence interval [CI]: 67.6%, 100%) and 98.4% specificity in 126 of 128 patients (95% CI: 94.5%, 99.6%). Considering both the hip and spine, the classification of patients at high risk for fracture by biomechanical CT analysis—those with osteoporosis or “fragile bone strength”—agreed well against classifications for clinical osteoporosis by DXA (T score ≤−2.5 at the hip or spine), with 82.8% sensitivity in 24 of 29 patients (95% CI: 65.4%, 92.4%) and 85.7% specificity in 66 of 77 patients (95% CI: 76.2%, 91.8%). Conclusion Retrospective biomechanical CT analysis of CT colonography for colorectal cancer screening provides a comprehensive osteoporosis assessment without requiring changes in imaging protocols. �

Colon distension and scan protocol for CT-colonography: an overview

NARCIS (Netherlands)

Boellaard, Thierry N.; de Haan, Margriet C.; Venema, Henk W.; Stoker, Jaap

2013-01-01

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,

Present status and future view on virtual endoscopy. Depiction of minute lesions in the large intestine with CT colonography

International Nuclear Information System (INIS)

Sugino, Yoshinori

2002-01-01

CT colonography is a new imaging technique using helical CT. We studied the efficacy of CT colonoscopy in the detection of small polyps and depiction of superficial lesions. Concerning the detection of small polyps, we studied 54 patients with abnormality checked by barium enema. Conventional colonoscopy revealed 79 lesions (5 advanced carcinomas, 4 superficial-type adenomas and 70 polyps). CT colonography identified all 5 carcinomas, 3 of the 4 superficial lesions and 43 of the 45 polyps that were 0.5 cm or smaller in diameter, 18 of 22 polyps that were 0.6 to 0.9 cm, and all 3 polyps that were 1.0 cm or more in diameter. There were 92 false positive polyps that were 0.5 cm or smaller in diameter. On a superficial lesion, we could depict a superficial depressive type early colonic carcinoma 1.0 cm in diameter, using very thin-slice CT equipment. In conclusion, CT colonography has a high sensitivity for detection of small polyps and sufficient capability for depiction of superficial lesions. CT colonography may be suitable for screening examinations of the large intestine. (author)

CT colonography and cost-effectiveness

Energy Technology Data Exchange (ETDEWEB)

Mavranezouli, Ifigeneia [University College London, National Collaborating Centre for Mental Health, Centre for Outcomes Research and Effectiveness, Sub-department of Clinical Health Psychology, London (United Kingdom); East, James E. [St Marks Hospital, Imperial College London, Wolfson Unit for Endoscopy, London (United Kingdom); Taylor, Stuart A. [University College Hospital, Specialist X-Ray, London (United Kingdom); University College Hospital, Department of Imaging, London (United Kingdom)

2008-11-15

CT colonography (CTC) is increasingly advocated as an effective initial screening tool for colorectal cancer. Nowadays, policy-makers are increasingly interested in cost-effectiveness issues. A number of studies assessing the cost-effectiveness of CTC have been published to date. The majority of findings indicate that CTC is probably not cost-effective when colonoscopy is available, but this conclusion is sensitive to a number of key parameters. This review discusses the findings of these studies, and considers those factors which most influence final conclusions, notably intervention costs, compliance rates, effectiveness of colonoscopy, and the assumed prevalence and natural history of diminutive advanced polyps. (orig.)

CT colonography and cost-effectiveness

International Nuclear Information System (INIS)

Mavranezouli, Ifigeneia; East, James E.; Taylor, Stuart A.

2008-01-01

CT colonography (CTC) is increasingly advocated as an effective initial screening tool for colorectal cancer. Nowadays, policy-makers are increasingly interested in cost-effectiveness issues. A number of studies assessing the cost-effectiveness of CTC have been published to date. The majority of findings indicate that CTC is probably not cost-effective when colonoscopy is available, but this conclusion is sensitive to a number of key parameters. This review discusses the findings of these studies, and considers those factors which most influence final conclusions, notably intervention costs, compliance rates, effectiveness of colonoscopy, and the assumed prevalence and natural history of diminutive advanced polyps. (orig.)

Comparative economic evaluation of data from the ACRIN National CT Colonography Trial with three cancer intervention and surveillance modeling network microsimulations.

Science.gov (United States)

Vanness, David J; Knudsen, Amy B; Lansdorp-Vogelaar, Iris; Rutter, Carolyn M; Gareen, Ilana F; Herman, Benjamin A; Kuntz, Karen M; Zauber, Ann G; van Ballegooijen, Marjolein; Feuer, Eric J; Chen, Mei-Hsiu; Johnson, C Daniel

2011-11-01

To estimate the cost-effectiveness of computed tomographic (CT) colonography for colorectal cancer (CRC) screening in average-risk asymptomatic subjects in the United States aged 50 years. Enrollees in the American College of Radiology Imaging Network National CT Colonography Trial provided informed consent, and approval was obtained from the institutional review board at each site. CT colonography performance estimates from the trial were incorporated into three Cancer Intervention and Surveillance Modeling Network CRC microsimulations. Simulated survival and lifetime costs for screening 50-year-old subjects in the United States with CT colonography every 5 or 10 years were compared with those for guideline-concordant screening with colonoscopy, flexible sigmoidoscopy plus either sensitive unrehydrated fecal occult blood testing (FOBT) or fecal immunochemical testing (FIT), and no screening. Perfect and reduced screening adherence scenarios were considered. Incremental cost-effectiveness and net health benefits were estimated from the U.S. health care sector perspective, assuming a 3% discount rate. CT colonography at 5- and 10-year screening intervals was more costly and less effective than FOBT plus flexible sigmoidoscopy in all three models in both 100% and 50% adherence scenarios. Colonoscopy also was more costly and less effective than FOBT plus flexible sigmoidoscopy, except in the CRC-SPIN model assuming 100% adherence (incremental cost-effectiveness ratio: $26,300 per life-year gained). CT colonography at 5- and 10-year screening intervals and colonoscopy were net beneficial compared with no screening in all model scenarios. The 5-year screening interval was net beneficial over the 10-year interval except in the MISCAN model when assuming 100% adherence and willingness to pay $50,000 per life-year gained. All three models predict CT colonography to be more costly and less effective than non-CT colonographic screening but net beneficial compared with no

CT colonography: current status in Europe and future perspectives

International Nuclear Information System (INIS)

Lefere, P.; Gryspeerdt, S.; Yoshida, H.

2007-01-01

In this article, we review the current status of CT colonography (CTC) in Europe and future perspectives of CTC including fecal tagging and CAD. There are several large multi-centre studies that have been initiated. Fecal tagging has gradually become a prerequisite to perform state-of-the-art CTC. However, CAD for fecal-tagging CTC remains a subject for future research. (orig.)

Teleradiology based CT colonography to screen a population group of a remote island; at average risk for colorectal cancer

International Nuclear Information System (INIS)

Lefere, Philippe; Silva, Celso; Gryspeerdt, Stefaan; Rodrigues, António; Vasconcelos, Rita; Teixeira, Ricardo; Gouveia, Francisco Henriques de

2013-01-01

Purpose: To prospectively assess the performance of teleradiology-based CT colonography to screen a population group of an island, at average risk for colorectal cancer. Materials and methods: A cohort of 514 patients living in Madeira, Portugal, was enrolled in the study. Institutional review board approval was obtained and all patients signed an informed consent. All patients underwent both CT colonography and optical colonoscopy. CT colonography was interpreted by an experienced radiologist at a remote centre using tele-radiology. Per-patient sensitivity, specificity, positive (PPV) and negative (NPV) predictive values with 95% confidence intervals (95%CI) were calculated for colorectal adenomas and advanced neoplasia ≥6 mm. Results: 510 patients were included in the study. CT colonography obtained a per-patient sensitivity, specificity, PPV and, NPV for adenomas ≥6 mm of 98.11% (88.6–99.9% 95% CI), 90.97% (87.8–93.4% 95% CI), 56.52% (45.8–66.7% 95% CI), 99.75% (98.4–99.9% 95% CI). For advanced neoplasia ≥6 mm per-patient sensitivity, specificity, PPV and, NPV were 100% (86.7–100% 95% CI), 87.07% (83.6–89.9% 95% CI), 34.78% (25.3–45.5% 95% CI) and 100% (98.8–100% 95% CI), respectively. Conclusion: In this prospective trial, teleradiology-based CT colonography was accurate to screen a patient cohort of a remote island, at average risk for colorectal cancer

Teleradiology based CT colonography to screen a population group of a remote island; at average risk for colorectal cancer

Energy Technology Data Exchange (ETDEWEB)

Lefere, Philippe, E-mail: radiologie@skynet.be [VCTC, Virtual Colonoscopy Teaching Centre, Akkerstraat 32c, B-8830 Hooglede (Belgium); Silva, Celso, E-mail: caras@uma.pt [Human Anatomy of Medical Course, University of Madeira, Praça do Município, 9000-082 Funchal (Portugal); Gryspeerdt, Stefaan, E-mail: stefaan@sgryspeerdt.be [VCTC, Virtual Colonoscopy Teaching Centre, Akkerstraat 32c, B-8830 Hooglede (Belgium); Rodrigues, António, E-mail: nucleo@nid.pt [Nucleo Imagem Diagnostica, Rua 5 De Outubro, 9000-216 Funchal (Portugal); Vasconcelos, Rita, E-mail: rita@uma.pt [Department of Engineering and Mathematics, University of Madeira, Praça do Município, 9000-082 Funchal (Portugal); Teixeira, Ricardo, E-mail: j.teixeira1947@gmail.com [Department of Gastroenterology, Central Hospital of Funchal, Avenida Luís de Camões, 9004513 Funchal (Portugal); Gouveia, Francisco Henriques de, E-mail: fhgouveia@netmadeira.com [LANA, Pathology Centre, Rua João Gago, 10, 9000-071 Funchal (Portugal)

2013-06-15

Purpose: To prospectively assess the performance of teleradiology-based CT colonography to screen a population group of an island, at average risk for colorectal cancer. Materials and methods: A cohort of 514 patients living in Madeira, Portugal, was enrolled in the study. Institutional review board approval was obtained and all patients signed an informed consent. All patients underwent both CT colonography and optical colonoscopy. CT colonography was interpreted by an experienced radiologist at a remote centre using tele-radiology. Per-patient sensitivity, specificity, positive (PPV) and negative (NPV) predictive values with 95% confidence intervals (95%CI) were calculated for colorectal adenomas and advanced neoplasia ≥6 mm. Results: 510 patients were included in the study. CT colonography obtained a per-patient sensitivity, specificity, PPV and, NPV for adenomas ≥6 mm of 98.11% (88.6–99.9% 95% CI), 90.97% (87.8–93.4% 95% CI), 56.52% (45.8–66.7% 95% CI), 99.75% (98.4–99.9% 95% CI). For advanced neoplasia ≥6 mm per-patient sensitivity, specificity, PPV and, NPV were 100% (86.7–100% 95% CI), 87.07% (83.6–89.9% 95% CI), 34.78% (25.3–45.5% 95% CI) and 100% (98.8–100% 95% CI), respectively. Conclusion: In this prospective trial, teleradiology-based CT colonography was accurate to screen a patient cohort of a remote island, at average risk for colorectal cancer.

Computer-aided diagnosis of colonic polyp by CT colonography

International Nuclear Information System (INIS)

Yoshida, Hiroyuki

2007-01-01

The outcome of National CT Colonography Trial, by American College of Radiology Imaging Network, 2006 (www.acrin.org/6664 protocol), possibly leads to the introduction of colorectal cancer screening in the US because CT colonography (CTCG) has been approved in the health insurance system. This paper describes the outline of computer-aided diagnosis (CAD) of colonic polyp by CTCG, its polyp detectability and future aspects. CTCG essentially derives from the virtual, abdominal 3D CT images and gives as many as about 500 images/patient, in the reading of which CAD support the expert. CAD technology in CTCG is said to have been essentially established in the first half of 2000s, which involves the cleansing of fecal tagging effect, extraction of the colonal wall from the image, detection of suspicious polyp, reduction of false-positive findings and displaying of the detected polyp. The detectability is thought to be at comparable level to expert's. The last displaying is done on the user-interface like Colon CAD Workstation. More efficient expert's reading with CAD, imaging without previous gut cleansing, detection of the flat lesion and further reduction of false-positive are the forthcoming tasks in clinical practice. Significance of CTCG is becoming in realization and its usage with CAD is thought to be more popular in Japan. (R.T.)

CT colonography combined with fistulography - a case of periannal fistula of a 6 months old child

International Nuclear Information System (INIS)

Sirakov, N.; Velkova, K.; Sirakov, V.; Tashev, P.

2007-01-01

We present a 6 months old child with perianal fistula with repeated secretion from it. The child was examined by double contrast barium enema and transrectal ultrasonography that gave suggestions of perianal fistula with no communication to the rectum and suspicion of a anal duplication of the rectum. The child was examined by CT colonography combined with fistulography. The exam was carried out on a axial CT Somatom Emotion by Siemens. The purpose of our report is to present the results of the combination of CT colonography and fistulography, applied to a 6-month-old child, as well as to present the specific protocol that we used for this examination. (authors)

Colon distension and scan protocol for CT-colonography: An overview

Energy Technology Data Exchange (ETDEWEB)

Boellaard, Thierry N., E-mail: t.n.boellaard@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Haan, Margriet C. de, E-mail: m.c.dehaan@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Venema, Henk W., E-mail: h.w.venema@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Stoker, Jaap, E-mail: j.stoker@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands)

2013-08-15

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.

Effective radiation doses in CT colonography: results of an inventory among research institutions

International Nuclear Information System (INIS)

Jensch, Sebastiaan; Gelder, Rogier E. van; Lameris, Johan S.; Stoker, Jaap; Venema, Henk W.; Reitsma, Johannes B.; Bossuyt, Patrick M.M.

2006-01-01

The purpose of this study was to estimate the effective dose that is currently used in CT colonography using scan parameters that were collected for this purpose, and to investigate trends in time. PubMed was systematically searched from 1996 until January 2004 for studies investigating CT colonography. Research institutions were contacted and asked for their current scan protocol. Thirty-six institutions published 74 studies. Twenty-eight of the 36 institutions provided their current protocol. The median effective dose in 2004 was 5.1 mSv (range 1.2-11.7 mSv) per position. Most institutions (93%) scan in both the supine and prone positions. The median mAs value was 67 mAs (range 20-200), median collimation was 2.5 mm (range 0.75-5). From 1996 until 2004 a significant decrease in mAs and collimation (P=0.006, P<0.0001, respectively) was observed, while institutions that used a multislice scanner increased (P<0.0001). The effective dose remained constant (P=0.76). In 2004 the median effective dose for a complete CT colonography was 10.2 mSv. Despite the increasing use of multislice scanners, which are slightly less dose-efficient, the median effective dose remained approximately constant between 1996 and 2004. This is mainly caused by the use of lower mAs settings. (orig.)

Diagnostic value of CT-colonography as compared to colonoscopy in an asymptomatic screening population: a meta-analysis

International Nuclear Information System (INIS)

Haan, Margriet C. de; Gelder, Rogier E. van; Bipat, Shandra; Stoker, Jaap; Graser, Anno

2011-01-01

Previous meta-analyses on CT-colonography included both average and high risk individuals, which may overestimate the diagnostic value in screening. A meta-analysis was performed to obtain the value of CT-colonography for screening. A search was performed using PubMed, Embase and Cochrane. Article selection and critical appraisal was done by two reviewers. Inclusion criteria: prospective, randomized trials or cohort studies comparing CT-colonography with colonoscopy (≥50 participants), ≥95% average risk participants ≥50 years. Study characteristics and 2 x 2 contingency Tables were recorded. Sensitivity and specificity estimates were calculated per patient and per polyp (≥6 mm, ≥10 mm), using univariate and bivariate analyses. Five of 1,021 studies identified were included, including 4,086 participants ( 2 -values showed substantial heterogeneity, especially for 6-9 mm polyps and adenomas: 68.1% vs. 78.6% (sensitivity per patient). Estimated sensitivities for patients with polyps or adenomas ≥ 6 mm were 75.9% and 82.9%, corresponding specificities 94.6% and 91.4%. Estimated sensitivities for patients with polyps or adenomas ≥ 10 mm were 83.3% and 87.9%, corresponding specificities 98.7% and 97.6%. Estimated sensitivities per polyp for advanced adenomas ≥ 6 mm and ≥ 10 mm were 83.9% and 83.8%. Compared to colonoscopy, CT-colonography has a high sensitivity for adenomas ≥ 10 mm. For (advanced) adenomas ≥ 6 mm sensitivity is somewhat lower. (orig.)

Limited-preparation CT colonography in frail elderly patients: a feasibility study.

LENUS (Irish Health Repository)

Keeling, Aoife N

2010-05-01

Full colonic preparation can be onerous and may be poorly tolerated in frail elderly patients. The purpose of this study was to prospectively assess the image quality and diagnostic yield of limited-preparation CT colonography (CTC) in elderly patients with suspected colorectal cancer who were deemed medically unfit or unsuitable for colonoscopy.

CT colonography: Diagnostic role of contrast enhancement of benign polyps and colorectal carcinoma

International Nuclear Information System (INIS)

Stoinova, V.; Nedevska, M.

2006-01-01

Full text: The aim of this study was to compare pre- and postcontrast CT attenuation values of benign colorectal polyps and carcinoma lesions detected by CT colonography, and to investigate whether contrast enhancement of these lesions can be potentially used for differentiation from residual fluid and feces. We retrospectively reviewed CT colonographic dataset of 120 patients. 35 benign polyps and 22 colorectal carcinomas were included in our study. All lesions were confirmed by colonoscopic biopsy or surgery. The difference in attenuation value between precontrast and postcontrast studies of polyps was statistically significant; the same was true for colorectal cancers. In the precontrast phase no statistically significant difference was observed between stool, polyps and cancers. The mean attenuation value of solid fecal residuals was 37 HU before and after contrast enhancement. Residual fluid do not take up contrast and the density does not change in the contrast-enhanced phase. The difference between postcontrast density of polyps and cancers with respect to density of stools and residual fluid was significant. The use of contrast medium could be helpful in CT colonography for discriminating polypoid benign lesions and colorectal cancer from fecal and fluid residuals

Effects of different components of Mao Dongqing's total flavonoids and total saponins on transient ischemic attack (TIA) model of rats.

Science.gov (United States)

Miao, Ming-San; Peng, Meng-Fan; Ma, Rui-Juan; Bai, Ming; Liu, Bao-Song

2018-03-01

Objective: To study the effects of the different components of the total flavonoids and total saponins from Mao Dongqing's active site on the rats of TIA model, determine the optimal reactive components ratio of Mao Dongqing on the rats of TIA. Methods: TIA rat model was induced by tail vein injection of tert butyl alcohol, the blank group was injected with the same amount of physiological saline, then behavioral score wasevaluated. Determination the level of glutamic acid in serum, the activity of Na+-K+-ATP enzyme, CA ++ -ATP enzyme and Mg ++ -ATP enzyme in Brain tissue, observe the changes of hippocampus in brain tissue, the comprehensive weight method was used to evaluate the efficacy of each component finally. Results: The contents of total flavonoids and total saponins in the active part of Mao Dongqing can significantly improve the pathological changes of brain tissue in rats, improve the activity of Na + -K + -ATP enzyme, Ca ++ -ATP enzyme and Mg ++ -ATP enzyme in the brain of rats, and reduce the level of glutamic acid in serum. The most significant of the contents was the ratio of 10:6. The different proportions of total flavonoids and total saponins in the active part of Mao Dongqing all has a better effect on the rats with TIA, and the ratio of 10:6 is the best active component for preventing and controlling TIA.

PET/CT colonography: a novel non-invasive technique for assessment of extent and activity of ulcerative colitis

Energy Technology Data Exchange (ETDEWEB)

Das, Chandan J.; Sharma, Raju [All India Institute of Medical Sciences, Department of Radiodiagnosis, New Delhi (India); Makharia, Govind K.; Tiwari, Rajeew P. [All India Institute of Medical Sciences, Department of Gastroenterology and Human Nutrition, New Delhi (India); Kumar, Rakesh; Kumar, Rajender; Malhotra, Arun [All India Institute of Medical Sciences, Department of Nuclear Medicine, New Delhi (India)

2010-04-15

Extent of involvement and activity of ulcerative colitis (UC) is best evaluated by colonoscopy. Colonoscopy however carries risk during acute exacerbation. We investigated the utility of PET/CT colonography for assessment of extent and activity of UC. Within a 1-week window, 15 patients with mild to moderately active UC underwent colonoscopy and PET/CT colonography 60 min after injection of 10 mCi of {sup 18}F-fluorodeoxyglucose (FDG). PET activity score based on the amount of FDG uptake and endoscopic mucosal activity in seven colonic segments of each patient was recorded. The mean maximum standardized uptake value (SUV{sub max}) of seven segments was compared with activity in liver. A PET activity grade of 0, 1, 2 or 3 was assigned to each region depending upon their SUV{sub max} ratio (colon segment to liver). The extent of disease was left-sided colitis in five and pancolitis in ten. The mean Ulcerative Colitis Disease Activity Index (UCDAI) was 7.6. The number of segments involved as per colonoscopic evaluation and PET/CT colonography was 67 and 66, respectively. There was a good correlation for extent evaluation between the two modalities (kappa 55.3%, p = 0.02). One patient had grade 0 PET activity, nine had grade 2 and five had grade 3 PET activity. In six patients, there was one to one correlation between PET activity grades with that of endoscopic grade. One patient showed activity in the sacroiliac joint suggesting active sacroiliitis. PET/CT colonography is a novel non-invasive technique for the assessment of extent and activity of the disease in patients with UC. (orig.)

Evaluation of a radiographer tele-training programme in the interpretation of CT Colonography

DEFF Research Database (Denmark)

Lauridsen, Carsten Ammitzbøl; Lefere, Philippe

2012-01-01

Colorectal cancer is one of the most common, and deadly human cancers. By early identifi cation of suspect lesions, screening has the potential to reduce mortality. Colonos- copy remains the screening gold standard, but “virtual colonoscopy“ or CT-colonography (CTC) has been shown to generate...

Comparison of a 4-Day versus 2-Day Low Fiber Diet Regimen in Barium Tagging CT Colonography in Incomplete Colonoscopy Patients

Directory of Open Access Journals (Sweden)

Kaan Meric

2015-01-01

Full Text Available Our aim was to compare the amount of residual feces, residual fluid, the tagging quality, and patient compliance using 4-day versus 2-day low fiber diet regimen in barium tagging CT colonography in incomplete colonoscopy patients. Methods. A total of 101 patients who underwent CT colonography were assigned to 2-day diet group (n=56 and 4-day diet group (n=45. Fecal tagging was achieved with barium sulphate while bisacodyl and sennoside B were used for bowel preparation. Residual solid stool was divided into two groups measuring 0.05. The prevalence of moderate discomfort was significantly higher in 4-day group (P<0.001. Conclusion. Our study shows that 2-day limited bowel preparation regimen for fecal tag CT colonography is a safe and reasonable technique to evaluate the entire colon, particularly in incomplete conventional colonoscopy patients.

CT colonography: Project of High National Interest No. 2005062137 of the Italian Ministry of Education, University and Research (MIUR).

Science.gov (United States)

Neri, E; Laghi, A; Regge, D; Sacco, P; Gallo, T; Turini, F; Talini, E; Ferrari, R; Mellaro, M; Rengo, M; Marchi, S; Caramella, D; Bartolozzi, C

2008-12-01

The aim of this paper is to describe the Web site of the Italian Project on CT Colonography (Research Project of High National Interest, PRIN No. 2005062137) and present the prototype of the online database. The Web site was created with Microsoft Office Publisher 2003 software, which allows the realisation of multiple Web pages linked through a main menu located on the home page. The Web site contains a database of computed tomography (CT) colonography studies in the Digital Imaging and Communications in Medicine (DICOM) standard, all acquired with multidetector-row CT according to the parameters defined by the European Society of Abdominal and Gastrointestinal Radiology (ESGAR). The cases present different bowel-cleansing and tagging methods, and each case has been anonymised and classified according to the Colonography Reporting and Data System (C-RADS). The Web site is available at http address www.ctcolonography.org and is composed of eight pages. Download times for a 294-Mbyte file were 33 min from a residential ADSL (6 Mbit/s) network, 200 s from a local university network (100 Mbit/s) and 2 h and 50 min from a remote academic site in the USA. The Web site received 256 accesses in the 22 days since it went online. The Web site is an immediate and up-to-date tool for publicising the activity of the research project and a valuable learning resource for CT colonography.

Extra colonic Findings on CT Colonography in Symptomatic Patients

International Nuclear Information System (INIS)

Drahovska, I.; Nigut, F.; Mach, P.; Lazurova, I.; Gombosova, L.

2011-01-01

The paper is an analysis of the consequences of the extra colonic findings identified on CT colonography examination of symptomatic patients and the validity of the intravenous application of contrast medium in this examination. The authors enrolled 252 patients, who underwent CT colonogprahy.128 extra colonic findings was identified in 80 patients (31.74%). The average age was 65.62 years (SD = 12.7, min. age was 29, max. age. 85 years). According the clinical significance the extra colonic findings have been divided into three groups – low, moderate and very important extra colonic findings. Low significant findings were 68 (53.12%), moderate 26 (20.31%) and very important extra colonic findings were 34 (26.56%), of which 30 were malignant nature. (author)

Double Colorectal Cancer Only Diagnosed by Computed Tomographic Colonography

Directory of Open Access Journals (Sweden)

Koichi Nagata

2008-02-01

Full Text Available A 58-year-old woman presented to her physician with rectal bleeding and intermittent diarrhea. Optical colonoscopy revealed a bulky tumor which was diagnosed as rectal cancer. She was referred to our institution for further evaluation and treatment. Slim optical colonoscopy showed an obstructive cancer in the rectosigmoid junction and no information of the proximal side of the obstruction. The patient then underwent computed tomographic (CT colonography for further evaluation of the proximal side. Three-dimensional endoluminal ‘fly-through’ images revealed another protruded lesion in the proximal side of the obstruction. Diagnosis of synchronous double cancer was made by CT colonography. This CT data was not only used to create three-dimensional images but also to decide on a preoperative clinical staging. Laparoscopy-assisted high anterior resection was performed and T3 rectal cancer and T1 sigmoid colon cancer were confirmed in the resected specimen. Follow-up optical colonoscopy revealed no other tumors. CT colonography has recently become a popular preoperative examination tool with significant improvement in quality of image due to a rapid progress in computer technology. CT colonography correctly showed synchronous double cancer in our case and provided crucial information for planning surgery. We recommend that CT colonography should be used for evaluating the proximal side of obstructive colorectal cancer.

Electronic cleansing for 24-h limited bowel preparation CT colonography using principal curvature flow

NARCIS (Netherlands)

van Ravesteijn, Vincent F.; Boellaard, Thierry N.; van der Paardt, Marije P.; Serlie, Iwo W. O.; de Haan, Margriet C.; Stoker, Jaap; van Vliet, Lucas J.; Vos, Frans M.

2013-01-01

CT colonography (CTC) is one of the recommended methods for colorectal cancer screening. The subject's preparation is one of the most burdensome aspects of CTC with a cathartic bowel preparation. Tagging of the bowel content with an oral contrast medium facilitates CTC with limited bowel

CT colonography with minimal bowel preparation: evaluation of tagging quality, patient acceptance and diagnostic accuracy in two iodine-based preparation schemes

International Nuclear Information System (INIS)

Liedenbaum, Marjolein H.; Vries, A.H. de; Bipat, S.; Stoker, J.; Gouw, C.I.B.F.; Rijn, A.F. van; Dekker, E.

2010-01-01

The aim of this study was to compare a 1-day with a 2-day iodine bowel preparation for CT colonography in a positive faecal occult blood test (FOBT) screening population. One hundred consecutive patients underwent CT colonography and colonoscopy with segmental unblinding. The first 50 patients (group 1) ingested 7*50 ml iodinated contrast starting 2 days before CT colonography. The latter 50 patients (group 2) ingested 4*50 ml iodinated contrast starting 1 day before CT colonography. Per colonic segment measurements of residual stool attenuation and homogeneity were performed, and a subjective evaluation of tagging quality (grade 1-5) was done. Independently, two reviewers performed polyp and carcinoma detection. The tagging density was 638 and 618 HU (p = 0.458) and homogeneity 91 and 86 HU for groups 1 and 2, respectively (p = 0.145). The tagging quality was graded 5 (excellent) in 90% of all segments in group 1 and 91% in group 2 (p = 0.749). Mean per-polyp sensitivity for lesions ≥10 mm was 86% in group 1 and 97% in group 2 (p = 0.355). Patient burden from diarrhoea significantly decreased for patients in group 2. One-day preparation with meglumine ioxithalamate results in an improved patient acceptability compared with 2-day preparation and has a comparable, excellent image quality and good diagnostic performance. (orig.)

Evaluation of colonic lesions and pitfalls in CT colonography: A systematic approach based on morphology, attenuation and mobility

International Nuclear Information System (INIS)

Mang, Thomas; Gryspeerdt, Stefaan; Schima, Wolfgang; Lefere, Philippe

2013-01-01

Computed tomographic colonography is a reliable technique for the detection and classification of neoplastic and non-neoplastic lesions of the colon. It is based on a thin-section CT dataset of the cleansed and air-distended colon, acquired in prone and supine position. Two-dimensional and 3D projections are used in combination for image interpretation. The evaluation of CT colonography datasets is based on two steps, lesion perception to detect a polyp candidate and image interpretation to correctly characterize colonic filling defects. A thorough knowledge of the morphologic and attenuation characteristics of common colonic lesions and artifacts facilitates characterization of the findings. The purpose of this review article is to give an overview of the key CT colonographic imaging criteria to correctly characterize common colorectal lesions and to identify typical pitfalls and pseudolesions

Electronic cleansing for computed tomography (CT) colonography using a scale-invariant three-material model

NARCIS (Netherlands)

Serlie, Iwo W. O.; Vos, Frans M.; Truyen, Roel; Post, Frits H.; Stoker, Jaap; van Vliet, Lucas J.

2010-01-01

A well-known reading pitfall in computed tomography (CT) colonography is posed by artifacts at T-junctions, i.e., locations where air-fluid levels interface with the colon wall. This paper presents a scale-invariant method to determine material fractions in voxels near such T-junctions. The proposed

CT colonography: interpretative performance in a non-academic environment

International Nuclear Information System (INIS)

Burling, D.; Halligan, S.; Atchley, J.; Dhingsar, R.; Guest, P.; Hayward, S.; Higginson, A.; Jobling, C.; Kay, C.; Lilford, R.; Maskell, G.; McCafferty, I.; McGregor, J.; Morton, D.; Kumar Neelala, M.; Noakes, M.; Philips, A.; Riley, P.; Taylor, A.; Bassett, P.; Wardle, J.; Atkin, W.; Taylor, S.A.

2007-01-01

Aim: To investigate interpretative accuracy and reporting time for radiologists performing computed tomography (CT) colonography in day-to-day non-academic clinical practice. Materials and methods: Thirteen radiologists from seven centres, who were reporting CT colonography in non-academic daily clinical practice, interpreted a dataset of 15 colonoscopically validated cases in a controlled environment. Ten cases had either a cancer or polyp >10 mm; one case had a medium polyp and four were normal. Correct case categorization and interpretation times were compared using analysis of variance to aggregated results obtained from both experienced observers and observers recently trained using 50 cases, working in an academic environment. The effect of experience was determined using Spearman's rank correlation. Results: Individual accuracy was highly variable, range 53% (95% CI 27-79%) to 93% (95% CI 68-100%). Mean accuracy overall was significantly inferior to experienced radiologists (mean 75 versus 88%, p = 0.04) but not significantly different from recently trained radiologists (p = 0.48). Interpretation time was not significantly different to experienced readers (mean 12.4 min versus 11.7, p = 0.74), but shorter than recently trained radiologists (p = 0.05). There was a significant, positive, linear correlation between prior experience and accuracy (p < 0.001) with no plateau. Conclusion: Accuracy for sub-specialist radiologists working in a non-academic environment is, on average, equivalent to radiologists trained using 50 cases. However, there is wide variability in individual performance, which generally falls short of the average performance suggested by meta-analysis of published data. Experience improves accuracy, but alone is insufficient to determine competence

Improving Polyp Detection Algorithms for CT Colonography: Pareto Front Approach.

Science.gov (United States)

Huang, Adam; Li, Jiang; Summers, Ronald M; Petrick, Nicholas; Hara, Amy K

2010-03-21

We investigated a Pareto front approach to improving polyp detection algorithms for CT colonography (CTC). A dataset of 56 CTC colon surfaces with 87 proven positive detections of 53 polyps sized 4 to 60 mm was used to evaluate the performance of a one-step and a two-step curvature-based region growing algorithm. The algorithmic performance was statistically evaluated and compared based on the Pareto optimal solutions from 20 experiments by evolutionary algorithms. The false positive rate was lower (pPareto optimization process can effectively help in fine-tuning and redesigning polyp detection algorithms.

Bowel preparation in CT colonography: electrolyte and renal function disturbances in the frail and elderly patient.

LENUS (Irish Health Repository)

Mc Laughlin, Patrick

2010-03-01

Elderly patients are at increased risk of biochemical disturbances secondary to cathartic medications. This study investigates the renal function, electrolyte and clinical disturbances associated with CT colonography (CTC) with sodium picosulphate-magnesium citrate (SPS-MC) in a subgroup of frail, elderly patients.

Image quality and patient acceptance of four regimens with different amounts of mild laxatives for CT colonography

NARCIS (Netherlands)

Jensch, Sebastiaan; de Vries, Ayso H.; Pot, Dennis; Peringa, Jan; Bipat, Shandra; Florie, Jasper; van Gelder, Rogier E.; Stoker, Jaap

2008-01-01

OBJECTIVE: The purpose of our study was to prospectively evaluate image quality and patient acceptance of CT colonography (CTC) with fecal tagging using different levels of catharsis. SUBJECTS AND METHODS: Forty consecutive increased-risk patients were randomized. Group 1 received orally 20 mg of

Low-Fiber Diet in Limited Bowel Preparation for CT Colonography: Influence on Image Quality and Patient Acceptance

NARCIS (Netherlands)

Liedenbaum, Marjolein H.; Denters, Maaike J.; de Vries, Ayso H.; van Ravesteijn, Vincent F.; Bipat, Shandra; Vos, Frans M.; Dekker, Evelien; Stoker, Jaap

2010-01-01

OBJECTIVE. The purpose of this study was to determine whether a low-fiber diet is necessary for optimal tagging-only bowel preparation for CT colonography. SUBJECTS AND METHODS. Fifty consecutively enrolled patients received an iodine bowel preparation: 25 patients used a low-fiber diet and 25 used

Clinical study of CT colonography

International Nuclear Information System (INIS)

Nakazawa, Saburo; Hattori, Toshiyuki; Inui, Kazuo

2011-01-01

We studied the usefulness of CT colonography (CTC) for colon cancer diagnosis. CTC and optical colonoscopy were performed for 150 cases mainly including patients with a positive fecal occult blood test (FOBT). The results were compared and analyzed. The following are the final diagnoses given to the patients: advanced colon cancer: 41 cases; early cancer: 25 cases; adenoma: 74 cases; hyperplasia: 3 cases; submucosal tumor: 1 case; and no lesion: 6 cases. In terms of diagnostic performance of CTC, accuracy was found to be 96%, sensitivity was found to be 97.9%, and specificity was found to be 50%. Cancer stage-specific sensitivity was as follows: advanced colon cancer: 100%; early cancer: 96.3%; adenoma: 71.2%; and hyperplasia: 47.4%. Lesion site-specific sensitivity was as follows: caecum: 76.2%; ascending colon: 57.6%; transverse colon: 66.2%; descending colon: 83.3%; sigmoid colon: 85.1%; and rectum: 78.0%. Lesion size-specific sensitivity was as follows: 2 to 5 mm: 56.7%; 6 to 9 mm: 88.1%; 10 mm or more: 92.5%; and 6 mm or more: 90.9%. Therefore, the diagnostic sensitivity of CTC was confirmed to be high. The results suggest that CTC would be useful for colon cancer screening. (author)

Comparative evaluation of the fecal-tagging quality in CT colonography: barium vs. iodinated oral contrast agent.

Science.gov (United States)

Nagata, Koichi; Singh, Anand Kumar; Sangwaiya, Minal Jagtiani; Näppi, Janne; Zalis, Michael E; Cai, Wenli; Yoshida, Hiroyuki

2009-11-01

The purpose of this evaluation was to compare the tagging quality of a barium-based regimen with that of iodine-based regimens for computed tomographic (CT) colonography. Tagging quality was assessed retrospectively in three different types of fecal-tagging CT colonographic cases: 24 barium-based cases, 22 nonionic iodine-based cases, and 24 ionic iodine-based cases. For the purpose of evaluation, the large intestine was divided into six segments, and the tagging homogeneity of a total of 420 segments (70 patients) was graded by three blinded readers from 0 (heterogeneous) to 4 (homogeneous). For barium-based cases, the average score for the three readers was 2.4, whereas it was 3.4 for nonionic iodine and 3.6 for ionic iodine. The percentages of segments that were assigned scores of 4 (excellent tagging [100%]) were 11.6%, 61.9%, and 72.9% for the barium-based, nonionic iodine-based, and ionic iodine-based regimens, respectively. The homogeneity scores of iodine-based fecal-tagging regimens were significantly higher than those of the barium-based fecal-tagging regimen (P barium-based regimen (P barium-based fecal-tagging regimen. Iodine-based fecal-tagging regimens can provide an appropriate method for use in nonlaxative or minimum-laxative CT colonography.

Contrast-enhanced computed tomographic colonography in the follow-up of colorectal cancer patients: a feasibility study

International Nuclear Information System (INIS)

Laghi, Andrea; Iannaccone, Riccardo; Carbone, Iacopo; Piacentini, Francesca; Passariello, Roberto; Bria, Emilio; Trasatti, Luciana; Lauro, Salvatore; Vecchione, Aldo

2003-01-01

The aim of our study was to assess whether contrast-enhanced CT colonography is a feasible alternative to both conventional colonoscopy and liver ultrasonography in the follow-up program of colorectal cancer patients. Thirty-five patients, surgically treated for colorectal cancer, underwent a follow-up program that included physical examination, carcinoembryonic antigen serum assay, conventional colonoscopy, liver ultrasonography, and chest X-ray. For these patients, we added a yearly contrast-enhanced CT colonography. All CT examinations were performed with a high-resolution protocol using a multidetector spiral CT scanner (Siemens, Erlangen, Germany) prior to and after the administration of 130 ml of i.v. contrast material. Images were directly analyzed on a dedicated workstation by two radiologists to determine colonic evaluation, visualization of colonic anastomosis, presence of polyps, and extra-colonic findings. Colonic evaluation was judged as optimal in 91.7% of all colonic segments. All mechanical surgical anastomoses were visualized with CT colonography. There was no evidence of anastomotic recurrence. Seven polyps were detected in five different patients with CT colonography, with two false-positive and no false-negative examinations. Three liver metastases and two basal pulmonary nodules were also identified. Contrast-enhanced CT colonography is a feasible alternative to both conventional colonoscopy and liver ultrasonography in the follow-up of patients operated on for colorectal cancer. (orig.)

A comparison of primary two- and three-dimensional methods to review CT colonography

International Nuclear Information System (INIS)

Gelder, Rogier E. van; Florie, Jasper; Nio, C. Yung; Jager, Steven W. de; Lameris, Johan S.; Stoker, Jaap; Jensch, Sebastiaan; Vos, Frans M.; Venema, Henk W.; Bartelsman, Joep F.; Reitsma, Johannes B.; Bossuyt, Patrick M.M.

2007-01-01

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 (≥10 mm) polyps for primary 3D and 2D review was 81% (14.7/18) and 70%(12.7/18), respectively (p-values ≥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≥ 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. (orig.)

Colon distension, perceived burden and side-effects of CT-colonography for screening using hyoscine butylbromide or glucagon hydrochloride as bowel relaxant

NARCIS (Netherlands)

de Haan, Margriet C.; Boellaard, Thierry N.; Bossuyt, Patrick M.; Stoker, Jaap

2012-01-01

Objective: Compare colonic distension and perceived burden of CT-colonography between participants receiving hyoscine butylbromide (buscopan) and glucagon hydrochloride as bowel relaxant. Materials and methods: Data were collected within a screening trial. Participants received 20 mg buscopan

Colon distension, perceived burden and side-effects of CT-colonography for screening using hyoscine butylbromide or glucagon hydrochloride as bowel relaxant

International Nuclear Information System (INIS)

Haan, Margriet C. de; Boellaard, Thierry N.; Bossuyt, Patrick M.; Stoker, Jaap

2012-01-01

Objective: Compare colonic distension and perceived burden of CT-colonography between participants receiving hyoscine butylbromide (buscopan) and glucagon hydrochloride as bowel relaxant. Materials and methods: Data were collected within a screening trial. Participants received 20 mg buscopan intravenously or 1 mg of glucagon intravenously (if buscopan contra-indicated). Colon distension per segment was assessed using a 4-point scale (prone and supine). Data on perceived burden of CT-colonography were collected using a questionnaire two weeks after the examination. Outcome measures between groups were compared using propensity score matching. We used a stratified Wilcoxon–Mann–Whitney test statistic for quantitative and Cochran–Mantel–Haenszel statistics for categorical variables. Results: 541 participants were included: 336 (62%) received buscopan and 205 received glucagon. All buscopan recipients had an adequately distended colon, compared to 96% in the glucagon group (RR 7.31, 95% CI: 1.61–33.28). More glucagon recipients scored the insufflation as rather or extremely burdensome (25% vs. 16%; overall mean score 2.7 vs. 2.4; p < 0.001) and more found the entire CT-colonography rather or extremely burdensome (14% vs. 7%; 2.2 vs. 1.9; p = 0.001). Most frequently reported side effects were a dry mouth in the buscopan group (15%) and nausea in the glucagon group (13%). Conclusion: Compared to glucagon, premedication with buscopan results in significantly more adequately distended colons and a less burdensome procedure. When buscopan can be used, it is the preferred bowel relaxant.

Colon distension, perceived burden and side-effects of CT-colonography for screening using hyoscine butylbromide or glucagon hydrochloride as bowel relaxant

Energy Technology Data Exchange (ETDEWEB)

Haan, Margriet C. de, E-mail: margrietcdehaan@gmail.com [Department of Radiology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Boellaard, Thierry N., E-mail: t.n.boellaard@amc.uva.nl [Department of Radiology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Bossuyt, Patrick M., E-mail: p.m.bossuyt@amc.uva.nl [Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Stoker, Jaap, E-mail: j.stoker@amc.uva.nl [Department of Radiology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands)

2012-08-15

Objective: Compare colonic distension and perceived burden of CT-colonography between participants receiving hyoscine butylbromide (buscopan) and glucagon hydrochloride as bowel relaxant. Materials and methods: Data were collected within a screening trial. Participants received 20 mg buscopan intravenously or 1 mg of glucagon intravenously (if buscopan contra-indicated). Colon distension per segment was assessed using a 4-point scale (prone and supine). Data on perceived burden of CT-colonography were collected using a questionnaire two weeks after the examination. Outcome measures between groups were compared using propensity score matching. We used a stratified Wilcoxon-Mann-Whitney test statistic for quantitative and Cochran-Mantel-Haenszel statistics for categorical variables. Results: 541 participants were included: 336 (62%) received buscopan and 205 received glucagon. All buscopan recipients had an adequately distended colon, compared to 96% in the glucagon group (RR 7.31, 95% CI: 1.61-33.28). More glucagon recipients scored the insufflation as rather or extremely burdensome (25% vs. 16%; overall mean score 2.7 vs. 2.4; p < 0.001) and more found the entire CT-colonography rather or extremely burdensome (14% vs. 7%; 2.2 vs. 1.9; p = 0.001). Most frequently reported side effects were a dry mouth in the buscopan group (15%) and nausea in the glucagon group (13%). Conclusion: Compared to glucagon, premedication with buscopan results in significantly more adequately distended colons and a less burdensome procedure. When buscopan can be used, it is the preferred bowel relaxant.

Utility of minimal preparation ct colonography in detecting colorectal cancer in elderly and frail patients.

Science.gov (United States)

Meiklejohn, D J; Ridley, L J; Ngu, M C; Cowlishaw, J L; Duller, A; Ridley, W

2018-06-11

Colorectal cancers result in substantial morbidity and mortality to Australian society each year. The usual investigation for bowel malignancyis optical colonoscopy (OC), withcomputed tomographic colonography (CTC) used as an alternative investigation. The catharsis and colon insufflation associated with these investigations pose a higher risk in the elderly and frail. Risks include perforation, serum electrolyte disturbance, and anaesthesia/sedation risks.Minimal preparation computed tomographic colonography (MPCTC) eliminates these risks. This paper audits a 6-year period ofMPCTC in an Australian tertiary referral hospital. 145 patients underwent MPCTC during the study period. There were 7 true positives, 2 false positives and 2 false negatives. Analysis of this population indicates a sensitivity of 0.78 (95% CI 0.51 - 1.05), specificity of 0.99 (95% CI 0.97 - 1.01), positive predictive value (PPV) of 0.78 (95% CI 0.51 - 1.05) and negative predictive value (NPV) of 0.99 (95% CI 0.97 - 1.01). These findings are concordant with other published studies. The auditconfirmsthatminimal preparation CT colonography is a reasonable alternative to OC and CTC in detecting colorectal cancer in symptomatic elderly and frail patients, without the procedural risks inherent inmore invasive investigations. For most patients MPCTC ruled out significant colorectal carcinoma with a high negative predictive value. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Virtual colonoscopy (CT colonography) in the identification of colorectal cancer. A prospective study in symptomatic patients

International Nuclear Information System (INIS)

Regge, D.; Martincich, L.; Gallo, T.; Pollone, M.; Galatola, G.; Secreto, P.; Pera, A.; Rivolta, A.

2000-01-01

Aim of this study was to evaluate the sensitivity of virtual colonoscopy (CT colonography) in the identification of colorectal cancer and to define the limitations and the advantages of this imaging modality, as well as indications to the examination. It was examined prospectively 62 symptomatic patients aged 36 to 82 years (28 women and 34 men). All patients underwent both conventional and virtual colonoscopy on the same day; the conventional examination allowed exploration of the entire colon. Conventional colonoscopy identified 89 lesions 3-50 mm in diameter, namely 84 benign and 5 malignant lesions. No lesions were identified in 12 patients. CT colonography identified 52 of the 89 lesions, with 57.1% diagnostic accuracy. They were 11 false positives (82.5% positive predictive value and 52.2% specificity) and 37 false negatives (24.5% negative predictive value and 58.4% sensitivity). Sensitivity was significantly higher (85.7%) for polyps ≥ 1 cm. Virtual colonoscopy is an imaging modality with good diagnostic yield, well tolerated by patients and with great potentials for further development. It was suggested that the examination be performed in symptomatic patients who cannot undergo total colonoscopy or refuse the other imaging modalities. Further studies are waranted in larger series of patients, possibly introducing it in screening programs [it

Accuracy of Combined Computed Tomography Colonography and Dual Energy Iiodine Map Imaging for Detecting Colorectal masses using High-pitch Dual-source CT.

Science.gov (United States)

Sun, Kai; Han, Ruijuan; Han, Yang; Shi, Xuesen; Hu, Jiang; Lu, Bin

2018-02-28

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 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.

Patient experience of CT colonography and colonoscopy after fecal occult blood test in a national screening programme

OpenAIRE

Plumb, Andrew A.; Ghanouni, Alex; Rees, Colin J.; Hewitson, Paul; Nickerson, Claire; Wright, Suzanne; Taylor, Stuart A.; Halligan, Steve; von Wagner, Christian

2016-01-01

Objective To investigate patient experience of CT colonography (CTC) and colonoscopy in a national screening programme. Methods Retrospective analysis of patient experience postal questionnaires. We included screenees from a fecal occult blood test (FOBt) based screening programme, where CTC was performed when colonoscopy was incomplete or deemed unsuitable. We analyzed questionnaire responses concerning communication of test risks, test-related discomfort and post-test pain, as well as compl...

Patient experience of CT colonography and colonoscopy after fecal occult blood test in a national screening programme

OpenAIRE

Plumb, A. A.; Ghanouni, A.; Rees, C. J.; Hewitson, P.; Nickerson, C.; Wright, S.; Taylor, S. A.; Halligan, S.; von Wagner, C.

2017-01-01

OBJECTIVE: To investigate patient experience of CT colonography (CTC) and colonoscopy in a national screening programme. METHODS: Retrospective analysis of patient experience postal questionnaires. We included screenees from a fecal occult blood test (FOBt) based screening programme, where CTC was performed when colonoscopy was incomplete or deemed unsuitable. We analyzed questionnaire responses concerning communication of test risks, test-related discomfort and post-test pain, as well as com...

Comparison of polyp size and volume at CT colonography: implications for follow-up CT colonography.

Science.gov (United States)

Bethea, Emily; Nwawka, Ogonna K; Dachman, Abraham H

2009-12-01

The purpose of this study was to evaluate the reliability of polyp measurements at CT colonography and the factors that affect the measurements. Fifty colonoscopically proven cases of polyps 6 mm in diameter or larger were analyzed by two observers who measured each polyp in supine and prone views. Manual measurements of 2D volume by summation of areas, 2D maximum diameter, and 3D maximum diameter and automated measurements of 3D maximum diameter and volume were recorded for each observer and were repeated for one of the observers. Intraobserver and interobserver agreement was calculated. Analysis was performed to determine the measurement parameter that correlated most with summation-of-areas volume. Supine and prone measurements as a surrogate for tracking change in polyp size over time were analyzed to determine the measurement parameter with the least variation. Maximum diameter measured manually on 3D images had the highest correlation with summation-of-areas volume. Manual summation-of-areas volume was found to have the least variation between supine and prone measurements. Linear polyp measurement in the 3D endoluminal view appears to be the most reliable parameter for use in the decision to excise a polyp according to current guidelines. In our study, manual calculation of volume with summation of areas was found to be the most reliable measurement parameter for observing polyp growth over serial examinations. High reliability of polyp measurements is essential for adequate assessment of change in polyp size over serial examinations because many patients with intermediate-size polyps are expected to choose surveillance.

Assessment of the Incremental Benefit of Computer-Aided Detection (CAD) for Interpretation of CT Colonography by Experienced and Inexperienced Readers

Science.gov (United States)

Boone, Darren; Mallett, Susan; McQuillan, Justine; Taylor, Stuart A.; Altman, Douglas G.; Halligan, Steve

2015-01-01

Objectives To quantify the incremental benefit of computer-assisted-detection (CAD) for polyps, for inexperienced readers versus experienced readers of CT colonography. Methods 10 inexperienced and 16 experienced radiologists interpreted 102 colonography studies unassisted and with CAD utilised in a concurrent paradigm. They indicated any polyps detected on a study sheet. Readers’ interpretations were compared against a ground-truth reference standard: 46 studies were normal and 56 had at least one polyp (132 polyps in total). The primary study outcome was the difference in CAD net benefit (a combination of change in sensitivity and change in specificity with CAD, weighted towards sensitivity) for detection of patients with polyps. Results Inexperienced readers’ per-patient sensitivity rose from 39.1% to 53.2% with CAD and specificity fell from 94.1% to 88.0%, both statistically significant. Experienced readers’ sensitivity rose from 57.5% to 62.1% and specificity fell from 91.0% to 88.3%, both non-significant. Net benefit with CAD assistance was significant for inexperienced readers but not for experienced readers: 11.2% (95%CI 3.1% to 18.9%) versus 3.2% (95%CI -1.9% to 8.3%) respectively. Conclusions Concurrent CAD resulted in a significant net benefit when used by inexperienced readers to identify patients with polyps by CT colonography. The net benefit was nearly four times the magnitude of that observed for experienced readers. Experienced readers did not benefit significantly from concurrent CAD. PMID:26355745

PET/CT colonography in patients with colorectal polyps: a feasibility study

International Nuclear Information System (INIS)

Mainenti, Pier P.; Pace, Leonardo; Salvatore, Marco; Salvatore, Barbara; D'Antonio, Dario; Bucci, Luigi; De Falco, Teresa; De Palma, Giovanni D.; D'Armiento, Francesco P.

2007-01-01

To examine: (1) the feasibility of PET/CT colonography (PET/CTc) in patients with colorectal polyps; (2) the impact of metabolic information on CTc interpretation and, conversely, the impact of morphological information on PET characterisation of focal colorectal uptake. Ten patients with colorectal polyps underwent PET/CTc, followed within 3 h by therapeutic conventional colonoscopy (CC). A radiologist and a nuclear medicine physician analysed the PET/CTc images. The agreement of morphological and metabolic information in the colon and rectum was evaluated. The sensitivity and specificity of PET, CT and PET/CT were calculated for colorectal polyps. Seventeen polypoid lesions were identified at CC: six≤5 mm, six between 6 and 9 mm, and five ≥10 mm (four hyperplastic polyps, 11 tubular adenomas, one adenocarcinoma and one submucosal lipoma). A total of 20 scans (supine and prone) were performed in the ten patients: the agreement of morphological and metabolic information was excellent in 17 scans, good in two and moderate in one. PET/CTc showed a sensitivity of 91% for lesions ≥6 mm and a specificity of 100%. The metabolic information did not disclose any further polyps missed on CTc. The morphological information permitted correct classification of all eight instances of focal radiotracer uptake. PET/CTc is a feasible study. Adding a colonographic protocol to PET/CT images seems to allow correct characterisation of all cases of colorectal focal radiotracer uptake. The metabolic information does not seem to increase the accuracy of CTc. (orig.)

CT colonography for preoperative examination of the proximal colon using a transanal drainage tube for acute malignant colonic obstruction

International Nuclear Information System (INIS)

Sasaki, Kazuaki; Hirano, Yuji; Oono, Keisuke; Sasaki, Kazunori; Someya, Tetsufumi; Harada, Keisuke; Ezoe, Eiri; Furuhata, Tomohisa; Hirata, Koichi

2011-01-01

The purpose of this study was to evaluate the feasibility of CT colonography for preoperative examination of the proximal colon using a transanal drainage tube in patients with acute colon obstruction caused by colorectal cancer. Ten patients who received initial treatment for acute malignant colon obstruction at our hospital between June 2004 and December 2008 were studied. In these patients, elective surgery was possible after transanal drainage tube insertion, and the colon on the oral side from the cancer lesion was examined using a drainage tube. Air was injected through the tube into the oral side of the colon, and CT colonography was assessed for the presence or absence of lesions on the oral side. The images of the oral side of the colon were good enough to allow adequate interpretation in 9 of the 10 patients. In the first patient, the visualization of the area near the lesion was somewhat fair, although the right side colon was well visualized. There were no complications associated with this examination. The present preoperative examination using a transanal drainage tube was useful for determining the extent of intestinal resection when patients were not candidates for colonoscopy or barium enema examination. (author)

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

International Nuclear Information System (INIS)

Luboldt, W.; Kroll, M.; Wetter, A.; Vogl, T.J.; Toussaint, T.L.; Hoepffner, N.; Holzer, K.; Kluge, A.

2004-01-01

A computed tomography (CT) cut-off for differentiating neoplastic lesions (polyps/carcinoma) from normal colon in contrast-enhanced CT colonography (CTC) relating to the contrast phase and lesion size is determined. CT values of 64 colonic lesions (27 polyps 0 . The slope m was determined by linear regression in the correlation (lesion ∝[xA + (1 - x)V]//H) and the Y-intercept y 0 by the minimal shift of the line needed to maximize the accuracy of separating the colonic wall from the lesions. The CT value of the lesions correlated best with the intermediate phase: 0.4A+ 0.6V(r=0.8 for polyps ≥10 mm, r=0.6 for carcinomas, r=0.4 for polyps <10 mm). The accuracy in the differentiation between lesions and normal colonic wall increased with the height implemented as divisor, reached 91% and was obtained by the dynamic cut-off described by the formula: cut-off(A,V,H) = 1.1[0.4A + 0.6V]/H + 69.8. The CT value of colonic polyps or carcinomas can be increased extrinsically by scanning in the phase in which 0.4A + 0.6V reaches its maximum. Differentiating lesions from normal colon based on CT values is possible in contrast-enhanced CTC and improves when the cut-off is adjusted (normalized) to the contrast phase and lesion size. (orig.)

CT colonography and transient bacteraemia: implications for antibiotic prophylaxis

Energy Technology Data Exchange (ETDEWEB)

Ridge, C.A.; Carter, M.R.; Ryan, R.; Hegarty, C.; Malone, D.E. [St Vincent' s University Hospital, Department of Radiology, Dublin 4 (Ireland); Browne, L.P. [Texas Children' s Hospital, Department of Diagnostic Imaging, Houston, TX (United States); Schaffer, K. [St Vincent' s University Hospital, Department of Microbiology, Dublin 4 (Ireland)

2011-02-15

To determine the prevalence of transient bacteraemia after CT colonography (CTC). Blood cultures were obtained at 5, 10 and 15 min after CTC from 100 consecutive consenting patients. Blood samples were cultured in both aerobic and anaerobic media and positive blood culture samples were analysed by a microbiologist. Blood culture samples were positive for growth in sixteen patients. All positive blood culture samples were confirmed skin contaminants. There were no cases of significant bacteraemia. The estimated significant bacteraemia rate as a result of CTC is 0-3.7%, based on 95% confidence intervals around extreme results using Wilson's score method. American Heart Association and National Institute for Clinical Excellence guidelines advise that antibiotic prophylaxis before lower gastrointestinal endoscopy is not indicated in patients with at risk cardiac lesions (ARCL) as the risk of a transient bacteraemia leading to infective endocarditis is low. These data show that the prevalence of transient bacteraemia after CTC is also low. It follows that patients with ARCL do not require antibiotic prophylaxis before CTC. (orig.)

CT colonography and transient bacteraemia: implications for antibiotic prophylaxis

International Nuclear Information System (INIS)

Ridge, C.A.; Carter, M.R.; Ryan, R.; Hegarty, C.; Malone, D.E.; Browne, L.P.; Schaffer, K.

2011-01-01

To determine the prevalence of transient bacteraemia after CT colonography (CTC). Blood cultures were obtained at 5, 10 and 15 min after CTC from 100 consecutive consenting patients. Blood samples were cultured in both aerobic and anaerobic media and positive blood culture samples were analysed by a microbiologist. Blood culture samples were positive for growth in sixteen patients. All positive blood culture samples were confirmed skin contaminants. There were no cases of significant bacteraemia. The estimated significant bacteraemia rate as a result of CTC is 0-3.7%, based on 95% confidence intervals around extreme results using Wilson's score method. American Heart Association and National Institute for Clinical Excellence guidelines advise that antibiotic prophylaxis before lower gastrointestinal endoscopy is not indicated in patients with at risk cardiac lesions (ARCL) as the risk of a transient bacteraemia leading to infective endocarditis is low. These data show that the prevalence of transient bacteraemia after CTC is also low. It follows that patients with ARCL do not require antibiotic prophylaxis before CTC. (orig.)

CT colonography and transient bacteraemia: implications for antibiotic prophylaxis.

LENUS (Irish Health Repository)

Ridge, C A

2012-02-01

OBJECTIVES: To determine the prevalence of transient bacteraemia after CT colonography (CTC). METHODS: Blood cultures were obtained at 5, 10 and 15 min after CTC from 100 consecutive consenting patients. Blood samples were cultured in both aerobic and anaerobic media and positive blood culture samples were analysed by a microbiologist. RESULTS: Blood culture samples were positive for growth in sixteen patients. All positive blood culture samples were confirmed skin contaminants. There were no cases of significant bacteraemia. The estimated significant bacteraemia rate as a result of CTC is 0-3.7%, based on 95% confidence intervals around extreme results using Wilson\\'s score method. CONCLUSIONS: American Heart Association and National Institute for Clinical Excellence guidelines advise that antibiotic prophylaxis before lower gastrointestinal endoscopy is not indicated in patients with at risk cardiac lesions (ARCL) as the risk of a transient bacteraemia leading to infective endocarditis is low. These data show that the prevalence of transient bacteraemia after CTC is also low. It follows that patients with ARCL do not require antibiotic prophylaxis before CTC.

Computer-aided detection in CT colonography: initial clinical experience using a prototype system

International Nuclear Information System (INIS)

Graser, A.; Geisbuesch, S.; Reiser, M.F.; Becker, C.R.; Kolligs, F.T.; Schaefer, C.; Mang, T.

2007-01-01

Computer-aided detection (CAD) algorithms help to detect colonic polyps at CT colonography (CTC). The purpose of this study was to evaluate the accuracy of CAD versus an expert reader in CTC. One hundred forty individuals (67 men, 73 women; mean age, 59 years) underwent screening 64-MDCT colonography after full cathartic bowel cleansing without fecal tagging. One expert reader interpreted supine and prone scans using a 3D workstation with integrated CAD used as ''second reader.'' The system's sensitivity for the detection of polyps, the number of false-positive findings, and its running time were evaluated. Polyps were classified as small (≤5 mm), medium (6-9 mm), and large (≥10 mm). A total of 118 polyps (small, 85; medium, 19; large, 14) were found in 56 patients. CAD detected 72 polyps (61%) with an average of 2.2 false-positives. Sensitivity was 51% (43/85) for small, 90% (17/19) for medium, and 86% (12/14) for large polyps. For all polyps, per-patient sensitivity was 89% (50/56) for the radiologist and 73% (41/56) for CAD. For large and medium polyps, per-patient sensitivity was 100% for the radiologist, and 96% for CAD. In conclusion, CAD shows high sensitivity in the detection of clinically significant polyps with acceptable false-positive rates. (orig.)

Multidetector CT of the colon

International Nuclear Information System (INIS)

Luboldt, W.; Hoepffner, N.; Holzer, K.

2003-01-01

Multidetector technology, enabling faster imaging, higher spatial resolution and reduction in radiation dose, increases the role of CT in colonic diagnostic. The higher spatial resolution in the z-direction also changes the way to analyze the images. Instead of reading axial sections, now the colon can be systematically assessed in 3D by scrolling through multiplanar reconstructions or in CT colonography by virtual endoscopy. With ongoing improvements in computer-aided diagnosis CT colonography becomes an alternative to fiberoptic colonocopy for screening (http://www.multiorganscreening.org). In this article we propose a CT examination protocol for the colon, describe the typical imaging findings of different colonic diseases, and summarize the current status of CT colonography. (orig.)

Effect of computer-aided detection as a second reader in multidetector-row CT colonography

International Nuclear Information System (INIS)

Mang, Thomas; Peloschek, Philipp; Plank, Christina; Maier, Andrea; Weber, Michael; Herold, Christian; Schima, Wolfgang; Graser, Anno; Bogoni, Luca

2007-01-01

Our purpose was to assess the effect of computer-aided detection (CAD) on lesion detection as a second reader in computed tomographic colonography, and to compare the influence of CAD on the performance of readers with different levels of expertise. Fifty-two CT colonography patient data-sets (37 patients: 55 endoscopically confirmed polyps ≥0.5 cm, seven cancers; 15 patients: no abnormalities) were retrospectively reviewed by four radiologists (two expert, two nonexpert). After primary data evaluation, a second reading augmented with findings of CAD (polyp-enhanced view, Siemens) was performed. Sensitivities and reading time were calculated for each reader without CAD and supported by CAD findings. The sensitivity of expert readers was 91% each, and of nonexpert readers, 76% and 75%, respectively, for polyp detection. CAD increased the sensitivity of expert readers to 96% (P = 0.25) and 93% (P = 1), and that of nonexpert readers to 91% (P = 0.008) and 95% (P = 0.001), respectively. All four readers diagnosed 100% of cancers, but CAD alone only 43%. CAD increased reading time by 2.1 min (mean). CAD as a second reader significantly improves sensitivity for polyp detection in a high disease prevalence population for nonexpert readers. CAD causes a modest increase in reading time. CAD is of limited value in the detection of cancer. (orig.)

Colonic angiodysplasia on CT colonography: case report and characteristic imaging findings

Directory of Open Access Journals (Sweden)

Laura Filograna, MD

2017-12-01

Full Text Available Gastrointestinal angiodysplasia represents the cause of 6% of lower gastrointestinal tract bleeding, particularly in the elderly. Because of the common presentation and age range of affected patients, often patients with occult or massive gastrointestinal bleedings are investigated with colonoscopy, in the suspect of colonic cancer. Other methods are capsule enteroscopy, angiography, double-contrast barium enema, computed tomography angiography, and radionuclide scanning. In this contribution, we describe a case of colonic angiodysplasia first suspected during computed tomography colonography performed after an incomplete colonoscopy in a patient with recent anemization. The purpose is to highlight the computed tomography colonography imaging characteristics of this rare finding during such examination performed due to suspected colon carcinoma as a complementary or substitutive method of colonoscopy.

CT colonography without cathartic preparation: positive predictive value and patient experience in clinical practice

Energy Technology Data Exchange (ETDEWEB)

Zueco Zueco, Carmen; Sobrido Sampedro, Carolina; Corroto, Juan D.; Rodriguez Fernandez, Paula; Fontanillo Fontanillo, Manuela [Complexo Hospitalario Universitario de Vigo - CHUVI, Vigo, Pontevedra (Spain)

2012-06-15

To determine the positive predictive value (PPV) for polyps {>=}6 mm detected at CT colonography (CTC) performed without cathartic preparation, with low-dose iodine faecal tagging regimen and to evaluate patient experience. 1920 average-risk patients underwent CTC without cathartic preparation. Faecal tagging was performed by diatrizoate meglumine and diatrizoate sodium at a total dose of 60 ml (22.2 g of iodine).The standard interpretation method was primary 3D with 2D problem solving. We calculated per-patient and per-polyp PPV in relation to size and morphology. All colonic segments were evaluated for image quality (faecal tagging, amount of liquid and solid residual faeces and luminal distension). Patients completed a questionnaire before and after CTC to assess preparation and examination experience. Per-polyp PPV for detected lesions of {>=}6 mm, 6-9 mm, {>=}10 mm and {>=}30 mm were 94.3%, 93.1%, 94.7% and 98%, respectively. Per-polyp PPV, according to lesion morphology, was 94.6%, 97.3% and 85.1% for sessile, pedunculated and flat polyps, respectively. Per-patient PPV was 92.8%. Preparation without frank cathartics was reported to cause minimal discomfort by 78.9% of patients. CTC without cathartic preparation and low-dose iodine faecal tagging may yield high PPVs for lesions {>=}6 mm and is well accepted by patients. circle Computed tomographic colonography (CTC) without cathartic preparation is well accepted by patients circle Cathartic-free faecal tagging CTC yields high positive predictive values circle CTC without cathartic preparation could improve uptake of colorectal cancer screening. (orig.)

Evaluation of different 16-row CT colonography protocols using a porcine model; Evaluation unterschiedlicher 16-Zeilen-CT-Colonographie-Protokolle am Schweinedarmmodell

Energy Technology Data Exchange (ETDEWEB)

Luz, O.; Schaefer, J.; Dammann, F.; Heuschmid, M.; Claussen, C.D. [Tuebingen Univ. (Germany). Abt. fuer Radiologische Diagnostik; Vonthein, R. [Universitaet Tuebingen (Germany). Institut fuer Biometrie

2004-10-01

Purpose: To develop and to test an easily produced biological colon model with simulated polypoid lesions. Application of this phantom for the selection of an optimized scan protocol of 16-row CT colonography (CTC) for clinical use. Methods and Material: Six polypoid lesions (1-6 mm) were simulated with sutures on the inner face of a porcine colon segment (20 cm). After distending the colon segment with air, the phantom was placed in a water quench and CT scans were performed on a MDCT-scanner (Somatom Sensation 16, Siemens, Forchheim). At constant values for collimation (16 x 0.75 mm) and voltage (120 kV), 54 different combinations of mAs values (50, 75 and 100 mAs), pitch factors (1, 1.25 and 1.5) and slice thicknesses (0.75, 1.0, 1.5, 2.0, 3.0 and 5.0 mm) were tested systematically. The phantom was scanned in the longitudinal and transverse axis to simulate the different orientation of the colon in the abdomen. Axial slice images and virtual endoscopic views of all data sets were presented separately to 2 radiologists who independently determined number and size of detectable polyps. Dose exposure was measured with an Alderson phantom. Results: The colon model offered a realistic imitation of a polyp-covered, human colon. The experimental set-up allowed a systematic evaluation of polyp detection related to lesion size, orientation of the colon and CTC parameters, with other influencing factors mostly excluded. Polyps were significantly better detected in the longitudinal than in the transverse orientation of the colon. For the detection of lesions of at least 3 mm, a low dose (50 mAs) 16-row CTC should be combined with a pitch of 1.5 and a maximum slice thickness of 3 mm. For the depiction of polyps smaller than 3 mm, slice thickness and pitch should amount to 1 mm and 1.0, respectively. Effective dose of this low dose protocol is 4.08 mSv. (orig.)

Computer-Aided Detection of Polyps in CT Colonography Using Logistic Regression

NARCIS (Netherlands)

Van Ravesteijn, V.F.; Van Wijk, C.; Vos, F.M.; Truyen, R.; Peters, J.F.; Stoker, J.; Van Vliet, L.J.

2010-01-01

We present a computer-aided detection (CAD) system for computed tomography colonography that orders the polyps according to clinical relevance. TheCADsystem consists of two steps: candidate detection and supervised classification. The characteristics of the detection step lead to specific choices

Cost analysis of colorectal cancer screening with CT colonography in Italy.

Science.gov (United States)

Mantellini, Paola; Lippi, Giuseppe; Sali, Lapo; Grazzini, Grazia; Delsanto, Silvia; Mallardi, Beatrice; Falchini, Massimo; Castiglione, Guido; Carozzi, Francesca Maria; Mascalchi, Mario; Milani, Stefano; Ventura, Leonardo; Zappa, Marco

2018-06-01

Unit costs of screening CT colonography (CTC) can be useful for cost-effectiveness analyses and for health care decision-making. We evaluated the unit costs of CTC as a primary screening test for colorectal cancer in the setting of a randomized trial in Italy. Data were collected within the randomized SAVE trial. Subjects were invited to screening CTC by mail and requested to have a pre-examination consultation. CTCs were performed with 64- and 128-slice CT scanners after reduced or full bowel preparation. Activity-based costing was used to determine unit costs per-process, per-participant to screening CTC, and per-subject with advanced neoplasia. Among 5242 subjects invited to undergo screening CTC, 1312 had pre-examination consultation and 1286 ultimately underwent CTC. Among 129 subjects with a positive CTC, 126 underwent assessment colonoscopy and 67 were ultimately diagnosed with advanced neoplasia (i.e., cancer or advanced adenoma). Cost per-participant of the entire screening CTC pathway was €196.80. Average cost per-participant for the screening invitation process was €17.04 and €9.45 for the pre-examination consultation process. Average cost per-participant of the CTC execution and reading process was €146.08 and of the diagnostic assessment colonoscopy process was €24.23. Average cost per-subject with advanced neoplasia was €3777.30. Cost of screening CTC was €196.80 per-participant. Our data suggest that the more relevant cost of screening CTC, amenable of intervention, is related to CTC execution and reading process.

CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden.

Science.gov (United States)

Neri, Emanuele; Faggioni, Lorenzo; Cerri, Francesca; Turini, Francesca; Angeli, Simone; Cini, Lorenzo; Perrone, Franco; Paolicchi, Fabio; Bartolozzi, Carlo

2010-10-01

Our aim is to compare the radiation dose associated with a low-dose CT colonography (CTC) protocol for colorectal cancer screening with that delivered by double-contrast barium enema (DCBE). CTC of twenty asymptomatic individuals (M:F = 10:10) participating to a colorectal cancer screening program and DCBE of fifteen patients (M:F = 6:9) were evaluated. For CTC, absorbed dose was determined by calculating the dose-length product for each CTC examination from measurements on a CT dose phantom equipped with a CT ion chamber. For DCBE, the free-in-air Kerma at the patient's X-ray entry surface and the Kerma-area product during fluoroscopy and fluorography were measured with a Barracuda system, with fluoroscopy times being recorded blinded to the performing operator. Effective dose at CTC was 2.17 ± 0.12 mSv, with good and excellent image quality in 14/20 (70%) and 6/20 cases (30%), respectively. With DCBE, effective patient dose was 4.12 ± 0.17 mSv, 1.9 times greater than CTC (P < 0.0001). Our results show that effective dose from screening CTC is substantially lower than that from DCBE, suggesting that CTC is the radiological imaging technique of the large bowel with the lowest risk of stochastic radiation effects.

Effect of a tele-training programme on radiographers in the interpretation of CT colonography

DEFF Research Database (Denmark)

Lauridsen, Carsten; Lefere, Philippe; Gerke, Oke

2012-01-01

OBJECTIVE: To assess the performance of radiographers in CT colonography (CTC) after a tele-training programme, supervised by 2 experienced radiologists. MATERIALS AND METHODS: Five radiographers underwent training in CTC using a tele-training programme mainly based on the interpretation of 75...... training cases performed in the novice department. To evaluate the educational performance, each radiographer was tested on 20 test cases with 27 lesions >6mm (12: 6-9mm; 15: >10mm). Sensitivity, specificity and PPV for polyps ≥6mm and ≥10mm were calculated with point estimates and 95% confidence interval...... (95% CI). The results were compared by comparing 95% CI with a 5% significance level. RESULTS: In the training cases overall per-polyp sensitivity was 57% (95% CI 46.1-67.9) and 69.1% (95% CI 50.6-87.5) for lesions ≥6mm and ≥10mm, respectively. Overall per patient sensitivity, specificity and PPV were...

Prevalence and distribution of colonic diverticula assessed with CT colonography (CTC)

Energy Technology Data Exchange (ETDEWEB)

De Cecco, Carlo Nicola [University of Rome ' ' Sapienza' ' - Polo Pontino, Department of Radiological Sciences, Oncology and Pathology, Latina (Italy); Medical University of South Carolina, Department of Radiology and Radiological Sciences, Charleston, SC (United States); Ciolina, Maria; Rengo, Marco; Bellini, Davide; Muscogiuri, Giuseppe; Iafrate, Franco; Laghi, Andrea [University of Rome ' ' Sapienza' ' - Polo Pontino, Department of Radiological Sciences, Oncology and Pathology, Latina (Italy); Annibale, Bruno [University of Rome ' ' Sapienza' ' - Sant' Andrea Hospital, Department of Digestive and Liver Disease, Rome (Italy); Maruotti, Antonello [University ' ' Roma Tre' ' , Department of Public Institutions, Economy and Society, Rome (Italy); University of Southampton, Southampton Statistical Sciences Research Institute and School of Mathematics, Southampton (United Kingdom); Saba, Luca [Azienda Ospedaliera Universitaria di Cagliari, Department of Radiology, Cagliari (Italy)

2016-03-15

This study aimed to evaluate the prevalence of colonic diverticula according to age, gender, distribution, disease extension and symptoms with CT colonography (CTC). The study population included 1091 consecutive patients who underwent CTC. Patients with diverticula were retrospectively stratified according to age, gender, clinical symptoms and colonic segment involvement. Extension of colonic diverticula was evaluated using a three-point quantitative scale. Using this data, a multivariate regression analysis was applied to investigate the existence of any correlation among variables. Colonic diverticula were observed in 561 patients (240 men, mean age 68 ± 12 years). Symptomatic uncomplicated diverticular disease (SUDD) was present in 47.4 % of cases. In 25.6 % of patients ≤40 years, at least one diverticulum in the colon was observed. Prevalence of right-sided diverticula in patients >60 years was 14.2 % in caecum and 18.5 % in ascending colon. No significant difference was found between symptomatic and asymptomatic patients regarding diverticula prevalence and extension. No correlation was present between diverticula extension and symptoms. The incidence of colonic diverticula appears to be greater than expected. Right colon diverticula do not appear to be an uncommon finding, with their prevalence increasing with patient age. SUDD does not seem to be related to diverticula distribution and extension. (orig.)

Prevalence and distribution of colonic diverticula assessed with CT colonography (CTC)

International Nuclear Information System (INIS)

De Cecco, Carlo Nicola; Ciolina, Maria; Rengo, Marco; Bellini, Davide; Muscogiuri, Giuseppe; Iafrate, Franco; Laghi, Andrea; Annibale, Bruno; Maruotti, Antonello; Saba, Luca

2016-01-01

This study aimed to evaluate the prevalence of colonic diverticula according to age, gender, distribution, disease extension and symptoms with CT colonography (CTC). The study population included 1091 consecutive patients who underwent CTC. Patients with diverticula were retrospectively stratified according to age, gender, clinical symptoms and colonic segment involvement. Extension of colonic diverticula was evaluated using a three-point quantitative scale. Using this data, a multivariate regression analysis was applied to investigate the existence of any correlation among variables. Colonic diverticula were observed in 561 patients (240 men, mean age 68 ± 12 years). Symptomatic uncomplicated diverticular disease (SUDD) was present in 47.4 % of cases. In 25.6 % of patients ≤40 years, at least one diverticulum in the colon was observed. Prevalence of right-sided diverticula in patients >60 years was 14.2 % in caecum and 18.5 % in ascending colon. No significant difference was found between symptomatic and asymptomatic patients regarding diverticula prevalence and extension. No correlation was present between diverticula extension and symptoms. The incidence of colonic diverticula appears to be greater than expected. Right colon diverticula do not appear to be an uncommon finding, with their prevalence increasing with patient age. SUDD does not seem to be related to diverticula distribution and extension. (orig.)

Effect of listening to music and essential oil inhalation on patients undergoing screening CT colonography: A randomized controlled trial

Energy Technology Data Exchange (ETDEWEB)

Nagata, Koichi, E-mail: Nagata7@aol.com [Department of Radiology, Kameda Medical Center, 929 Higashi-cho, Kamogawa, Chiba 296-8602 (Japan); Department of Radiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan); Cancer Screening Technology Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1, Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Iida, Nao, E-mail: n.iida-xray@kameda.jp [Department of Radiology, Kameda Medical Center Makuhari, 1-3, Nakase, Mihama-ku, Chiba 261-8501 (Japan); Kanazawa, Hidenori, E-mail: r0713hk@jichi.ac.jp [Department of Radiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan); Fujiwara, Masanori, E-mail: m_fujiwara@kameda.jp [Department of Radiology, Kameda Medical Center Makuhari, 1-3, Nakase, Mihama-ku, Chiba 261-8501 (Japan); Mogi, Tomohiro, E-mail: mogi-xray@kameda.jp [Department of Radiology, Kameda Medical Center Makuhari, 1-3, Nakase, Mihama-ku, Chiba 261-8501 (Japan); Mitsushima, Toru, E-mail: mitsushima@kameda.jp [Department of Gastroenterology, Kameda Medical Center Makuhari, 1-3, Nakase, Mihama-ku, Chiba 261-8501 (Japan); Lefor, Alan T., E-mail: alefor@jichi.ac.jp [Department of Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan); Sugimoto, Hideharu, E-mail: sugimoto@jichi.ac.jp [Department of Radiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan)

2014-12-15

Highlights: • Music does not decrease patients’ perceived pain or acceptance during CTC. • Aromatherapy does not affect patients’ perceived pain or experience during CTC. • Music and aroma had little effect on vital signs during CTC. • More participants who listened to music requested music during the next CTC. • More participants who inhaled aroma requested aroma during the next CTC. - Abstract: Objective: To prospectively evaluate the effect of listening to music and inhaling aroma oil on patients undergoing screening computed tomography colonography. Materials and methods: Two hundred and twenty four participants were randomly allocated to one of the four groups including: (1) combined music and aroma, (2) music alone, (3) aroma alone, and (4) control. The visual analog scale for pain and a questionnaire were used for subjective outcomes. We also used a pre-test–post-test design to compare the differences in blood pressure and heart rate as objective outcomes. Results: There were no statistical differences between the control group and other groups in the visual analog scale or changes in heart rate. Changes in blood pressure were similar. Participants reported good overall experiences. There were no differences in terms of overall satisfaction, pain rating, willingness to repeat the computed tomography colonography procedure in the future, or preference between colonoscopy and computed tomography colonography. More participants using music and/or aroma requested music and/or aroma during the next computed tomography colonography (P < 0.0001). Conclusion: Although audio and olfactory intervention had little effect on perceived pain or discomfort and vital signs, participants who listened to music and inhaled aroma during the computed tomography colonography preferred music and aroma during the next computed tomography colonography.

Effect of listening to music and essential oil inhalation on patients undergoing screening CT colonography: A randomized controlled trial

International Nuclear Information System (INIS)

Nagata, Koichi; Iida, Nao; Kanazawa, Hidenori; Fujiwara, Masanori; Mogi, Tomohiro; Mitsushima, Toru; Lefor, Alan T.; Sugimoto, Hideharu

2014-01-01

Highlights: • Music does not decrease patients’ perceived pain or acceptance during CTC. • Aromatherapy does not affect patients’ perceived pain or experience during CTC. • Music and aroma had little effect on vital signs during CTC. • More participants who listened to music requested music during the next CTC. • More participants who inhaled aroma requested aroma during the next CTC. - Abstract: Objective: To prospectively evaluate the effect of listening to music and inhaling aroma oil on patients undergoing screening computed tomography colonography. Materials and methods: Two hundred and twenty four participants were randomly allocated to one of the four groups including: (1) combined music and aroma, (2) music alone, (3) aroma alone, and (4) control. The visual analog scale for pain and a questionnaire were used for subjective outcomes. We also used a pre-test–post-test design to compare the differences in blood pressure and heart rate as objective outcomes. Results: There were no statistical differences between the control group and other groups in the visual analog scale or changes in heart rate. Changes in blood pressure were similar. Participants reported good overall experiences. There were no differences in terms of overall satisfaction, pain rating, willingness to repeat the computed tomography colonography procedure in the future, or preference between colonoscopy and computed tomography colonography. More participants using music and/or aroma requested music and/or aroma during the next computed tomography colonography (P < 0.0001). Conclusion: Although audio and olfactory intervention had little effect on perceived pain or discomfort and vital signs, participants who listened to music and inhaled aroma during the computed tomography colonography preferred music and aroma during the next computed tomography colonography

Incidental physiological sliding hiatal hernia: a single center comparison study between CT with water enema and CT colonography.

Science.gov (United States)

Revelli, Matteo; Furnari, Manuele; Bacigalupo, Lorenzo; Paparo, Francesco; Astengo, Davide; Savarino, Edoardo; Rollandi, Gian Andrea

2015-08-01

Hiatal hernia is a well-known factor impacting on most mechanisms underlying gastroesophageal reflux, related with the risk of developing complications such as erosive esophagitis, Barrett's esophagus and ultimately, esophageal adenocarcinoma. It is our firm opinion that an erroneous reporting of hiatal hernia in CT exams performed with colonic distention may trigger a consecutive diagnostic process that is not only unnecessary, inducing a unmotivated anxiety in the patient, but also expensive and time-consuming for both the patient and the healthcare system. The purposes of our study were to determine whether colonic distention at CT with water enema and CT colonography can induce small sliding hiatal hernias and to detect whether hiatal hernias size modifications could be considered significant for both water and gas distention techniques. We retrospectively evaluated 400 consecutive patients, 200 undergoing CT-WE and 200 undergoing CTC, including 59 subjects who also underwent a routine abdominal CT evaluation on a different time, used as internal control, while a separate group of 200 consecutive patients who underwent abdominal CT evaluation was used as external control. Two abdominal radiologists assessed the CT exams for the presence of a sliding hiatal hernia, grading the size as small, moderate, or large; the internal control groups were directly compared with the corresponding CT-WE or CTC study looking for a change in hernia size. We used the Student's t test applying a size-specific correction factor, in order to account for the effect of colonic distention: these "corrected" values were then individually compared with the external control group. A sliding hiatal hernia was present in 51 % (102/200) of the CT-WE patients and in 48.5 % (97/200) of the CTC patients. Internal control CT of the 31 patients with a hernia at CT-WE showed resolution of the hernia in 58.1 % (18/31) of patients, including 76.5 % (13/17) and 45.5 % (5/11) of small and moderate

Low-dose CT colonography in children: initial experience, technical feasibility and utility

International Nuclear Information System (INIS)

Anupindi, Sudha; Perumpillichira, James; Zalis, Michael E.; Jaramillo, Diego; Israel, Esther J.

2005-01-01

CT colonography (CTC) is utilized as a diagnostic tool in the detection of colon polyps and early colorectal cancer in adults. Large studies in the literature, although focused on adult populations, have shown CTC to be a safe, accurate, non-invasive technique. We evaluated the technical feasibility of CTC in children using a low-dose technique. From November 2001 to April 2004 we evaluated eight patients (3-17 years) with non-contrast CTC. Seven of the patients had CTC, followed by standard colonoscopy (SC) the same day; in one patient, CTC followed a failed SC. CTC results were compared to results of SC. The estimated effective dose from each CTC was calculated and compared to that of standard barium enema. CTC results were consistent with those of SC. Sensitivity for polyps 5-10 mm was 100%, and sensitivity for polyps 10 mm and larger was 66.7%. The estimated mean effective dose was 2.17 mSv for CTC, compared to the 5-6 mSv for a standard air-contrast barium enema in a small child. Our initial experience shows CTC in children is well-tolerated, safe, and useful. The procedure can be performed successfully with a low radiation dose, and preliminary results compare well with SC. (orig.)

Radiation protection in newer medical imaging techniques: CT colonography

International Nuclear Information System (INIS)

2008-01-01

Multislice/detector computed tomography (CT) scanning, applied to visualization of the colon in CT colonography (CTC), also known as virtual colonoscopy (VC), is a relatively new application of CT introduced in recent years. The possibility of its application in population screening techniques raises a number of questions. Effort is required to ensure that the benefit of this new practice will not pose an undue level of detriment to the individual in multiple examinations. For practitioners and regulators, it is evident that innovation has been driven by both the imaging industry and by an ever increasing array of new applications generated and validated in the clinical environment. Regulation, industrial standardization, safety procedures and advice on best practice lag (inevitably) behind the industrial and clinical innovations being achieved. This series of Safety Reports (Nos 58, 60 and 61) is designed to help fill this growing vacuum, by bringing up to date and timely advice to bear on the problems involved. Under its statutory responsibility to establish standards for the protection of people against exposure to ionizing radiation and to provide for worldwide application of these standards, the IAEA has developed the Fundamental Safety Principles and the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS). The BSS was issued by the IAEA and co-sponsored by the Food and Agriculture Organization of the United Nations (FAO), the International Labour Organisation (ILO), the OECD Nuclear Energy Agency (OECD/NEA), the Pan American Health Organization (PAHO) and the World Health Organization (WHO), and requires radiation protection of patients undergoing medical exposures through justification of the procedures involved and through optimization. The IAEA programme on radiation protection of patients encourages the reduction of patient doses without losing diagnostic benefits. To facilitate this

Design of a multicentre randomized trial to evaluate CT colonography versus colonoscopy or barium enema for diagnosis of colonic cancer in older symptomatic patients: The SIGGAR study

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Edwards Rob

2007-10-01

Full Text Available Abstract Background and Aims The standard whole-colon tests used to investigate patients with symptoms of colorectal cancer are barium enema and colonoscopy. Colonoscopy is the reference test but is technically difficult, resource intensive, and associated with adverse events, especially in the elderly. Barium enema is safer but has reduced sensitivity for cancer. CT colonography ("virtual colonoscopy" is a newer alternative that may combine high sensitivity for cancer with safety and patient acceptability. The SIGGAR trial aims to determine the diagnostic efficacy, acceptability, and economic costs associated with this new technology. Methods The SIGGAR trial is a multi-centre randomised comparison of CT colonography versus standard investigation (barium enema or colonoscopy, the latter determined by individual clinician preference. Diagnostic efficacy for colorectal cancer and colonic polyps measuring 1 cm or larger will be determined, as will the physical and psychological morbidity associated with each diagnostic test, the latter via questionnaires developed from qualitative interviews. The economic costs of making or excluding a diagnosis will be determined for each diagnostic test and information from the trial and other data from the literature will be used to populate models framed to summarise the health effects and costs of alternative approaches to detection of significant colonic neoplasia in patients of different ages, prior risks and preferences. This analysis will focus particularly on the frequency, clinical relevance, costs, and psychological and physical morbidity associated with detection of extracolonic lesions by CT colonography. Results Recruitment commenced in March 2004 and at the time of writing (July 2007 5025 patients have been randomised. A lower than expected prevalence of end-points in the barium enema sub-trial has caused an increase in sample size. In addition to the study protocol, we describe our approach to

An interview study analysing patients' experiences and perceptions of non-laxative or full-laxative preparation with faecal tagging prior to CT colonography

International Nuclear Information System (INIS)

Ghanouni, A.; Smith, S.G.; Halligan, S.; Taylor, S.A.; Plumb, A.; Boone, D.; Wagner, C. von

2013-01-01

Aim: To compare patients' experiences of either non- or full-laxative bowel preparation with additional faecal tagging and subsequent computed tomographic (CT) colonography using in-depth interviews to elicit detailed responses. Materials and methods: Patients who received CT colonography after non- (n = 9) or full-laxative (n = 9) preparation participated in a semi-structured telephone interview at least 2 days after the investigation. Full-laxative preparation consisted of magnesium citrate and sodium picosulphate administered at home (or polyethylene glycol, if contraindicated), followed by hospital-based faecal tagging with iohexol. Non-laxative preparation was home-based barium sulphate for faecal tagging. Interviews were transcribed and thematically analysed to identify recurrent themes on patients' perceptions and experiences. Results: Experiences of full-laxative preparation were usually negative and characterized by pre-test diarrhoea that caused significant interference with daily routine. Post-test flatus was common. Non-laxative preparation was well-tolerated; patients reported no or minimal changes to bowel habit and rapid return to daily routine. Patients reported worry and uncertainty about the purpose of faecal tagging. For iohexol, this also added burden from waiting before testing. Conclusion: Patients' responses supported previous findings that non-laxative preparation is more acceptable than full-laxative preparation but both can be improved. Faecal tagging used in combination with laxative preparation is poorly understood, adding burden and worry. Home-based non-laxative preparation is also poorly understood and patients require better information on the purpose and mechanism in order to give fully informed consent. This may also optimize adherence to instructions. Allowing home-based self-administration of all types of preparation would prevent waiting before testing

Bowel preparation for CT-colonography: Comparison of two different cleansing protocols

International Nuclear Information System (INIS)

Juchems, Markus S.; Hoffmann, Martin H.K.; Schmidt, Stefan A.; Apostel, Anna; Brambs, Hans-Juergen; Aschoff, Andrik J.

2006-01-01

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

CT colonography: computer-aided detection of morphologically flat T1 colonic carcinoma

International Nuclear Information System (INIS)

Taylor, Stuart A.; Iinuma, Gen; Saito, Yutaka; Zhang, Jie; Halligan, Steve

2008-01-01

The purpose was to evaluate the ability of computer-aided detection (CAD) software to detect morphologically flat early colonic carcinoma using CT colonography (CTC). Twenty-four stage T1 colonic carcinomas endoscopically classified as flat (width over twice height) were accrued from patients undergoing staging CTC. Tumor location was annotated by three experienced radiologists in consensus aided by the endosocpic report. CAD software was then applied at three settings of sphericity (0, 0.75, and 1). Computer prompts were categorized as either true positive (overlapping tumour boundary) or false positive. True positives were subclassified as focal or non focal. The 24 cancers were endoscopically classified as type IIa (n=11) and type IIa+IIc (n=13). Mean size (range) was 27 mm (7-70 mm). CAD detected 20 (83.3%), 17 (70.8%), and 13 (54.1%) of the 24 cancers at filter settings of 0, 0.75, and 1, respectively with 3, 4, and 8 missed cancers of type IIa, respectively. The mean total number of false-positive CAD marks per patient at each filter setting was 36.5, 21.1, and 9.5, respectively, excluding polyps. At all settings, >96.1% of CAD true positives were classified as focal. CAD may be effective for the detection of morphologically flat cancer, although minimally raised laterally spreading tumors remain problematic. (orig.)

Detection of flat colorectal polyps at screening CT colonography in comparison with conventional polypoid lesions

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Sakamoto, Takashi; Urata, Joji [Diagnostic Imaging Center, Saiseikai Kumamoto Hospital, Kumamoto (Japan); Mitsuzaki, Katsuhiko; Matsuda, Katsuhiko; Kawakami, Megumi [Medical Examination Center, Saiseikai Kumamoto Hospital, Kumamoto (Japan); Utsunomiya, Daisuke; Yamamura, Sadahiro; Yamashita, Yasuyuki [Diagnostic Radiology, Faculty of Life Sciences, Kumamoto Univ., Kumamoto (Japan)], e-mail: utsunomi@kumamoto-u.ac.jp

2012-09-15

Background: Although the screening of small, flat polyps is clinically important, the role of CT colonography (CTC) screening in their detection has not been thoroughly investigated. Purpose: To evaluate the detection capability and usefulness of CTC in the screening of flat and polypoid lesions by comparing CTC with optic colonoscopy findings as the gold standard. Material and Methods: We evaluated the CTC detection capability for flat colorectal polyps with a flat surface and a height not exceeding 3 mm (n = 42) by comparing to conventional polypoid lesions (n = 418) according to the polyp diameter. Four types of reconstruction images including multiplanar reconstruction, volume rendering, virtual gross pathology, and virtual endoscopic images were used for visual analysis. We compared the abilities of the four reconstructions for polyp visualization. Results: Detection sensitivity for flat polyps was 31.3 %, 44.4 %, and 87.5 % for lesions measuring 2-3 mm, 4-5 mm, and {>=}6 mm, respectively; the corresponding sensitivity for polypoid lesions was 47.6 %, 79.0 %, and 91.7 %. The overall sensitivity for flat lesions (47.6%) was significantly lower than polypoid lesions (64.1%). Virtual endoscopic imaging showed best visualization among the four reconstructions. Colon cancers were detected in eight patients by optic colonoscopy, and CTC detected colon cancers in all eight patients. Conclusion: CTC using 64-row multidetector CT is useful for colon cancer screening to detect colorectal polyps while the detection of small, flat lesions is still challenging.

Computer-assisted detection of colonic polyps with CT colonography using neural networks and binary classification trees

International Nuclear Information System (INIS)

Jerebko, Anna K.; Summers, Ronald M.; Malley, James D.; Franaszek, Marek; Johnson, C. Daniel

2003-01-01

Detection of colonic polyps in CT colonography is problematic due to complexities of polyp shape and the surface of the normal colon. Published results indicate the feasibility of computer-aided detection of polyps but better classifiers are needed to improve specificity. In this paper we compare the classification results of two approaches: neural networks and recursive binary trees. As our starting point we collect surface geometry information from three-dimensional reconstruction of the colon, followed by a filter based on selected variables such as region density, Gaussian and average curvature and sphericity. The filter returns sites that are candidate polyps, based on earlier work using detection thresholds, to which the neural nets or the binary trees are applied. A data set of 39 polyps from 3 to 25 mm in size was used in our investigation. For both neural net and binary trees we use tenfold cross-validation to better estimate the true error rates. The backpropagation neural net with one hidden layer trained with Levenberg-Marquardt algorithm achieved the best results: sensitivity 90% and specificity 95% with 16 false positives per study

Colon dissection: a new three-dimensional reconstruction tool for computed tomography colonography

International Nuclear Information System (INIS)

Roettgen, R.; Fischbach, F.; Plotkin, M.; Herzog, H.; Freund, T.; Schroeder, R. J.; Felix, R.

2005-01-01

Purpose: To improve the sensitivity of computed tomography (CT) colonography in the detection of polyps by comparing the 3D reconstruction tool 'colon dissection' and endoluminal view (virtual colonoscopy) with axial 2D reconstructions. Material and Methods: Forty-eight patients (22 M, 26 F, mean age 57±21) were studied after intra-anal air insufflation in the supine and prone positions using a 16-slice helical CT (16x0.625 mm, pitch 1.7; detector rotation time 0.5 s; 160 mAs und 120 kV) and conventional colonoscopy. Two radiologists blinded to the results of the conventional colonoscopy analyzed the 3D reconstruction in virtual-endoscopy mode, in colon-dissection mode, and axial 2D slices. Results: Conventional colonoscopy revealed a total of 35 polyps in 15 patients; 33 polyps were disclosed by CT methods. Sensitivity and specificity for detecting colon polyps were 94% and 94%, respectively, when using the 'colon dissection', 89% and 94% when using 'virtual endoscopy', and 62% and 100% when using axial 2D reconstruction. Sensitivity in relation to the diameter of colon polyps with 'colon dissection', 'virtual colonoscopy', and axial 2D-slices was: polyps with a diameter >5.0 mm, 100%, 100%, and 71%, respectively; polyps with a diameter of between 3 and 4.9 mm, 92%, 85%, and 46%; and polyps with a diameter <3 mm, 89%, 78%, and 56%. The difference between 'virtual endoscopy' and 'colon dissection' in diagnosing polyps up to 4.9 mm in diameter was statistically significant. Conclusion: 3D reconstruction software 'colon dissection' improves sensitivity of CT colonography compared with the endoluminal view

Five year colorectal cancer outcomes in a large negative CT colonography screening cohort

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Kim, David H.; Pooler, B.D.; Pickhardt, Perry J. [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); Weiss, Jennifer M. [University of Wisconsin School of Medicine and Public Health, Section of Gastroenterology, Department of Internal Medicine, Madison, WI (United States)

2012-07-15

To assess the 5-year incidence of clinically presenting colorectal cancers following a negative CT colonography (CTC) screening examination, as few patient outcome data regarding a negative CTC screening result exist. Negative CTC screening patients (n = 1,050) in the University of Wisconsin Health system over a 14-month period were included. An electronic medical record (EMR) review was undertaken, encompassing provider, colonoscopy, imaging and histopathology reports. Incident colorectal cancers and other important GI tumours were recorded. Of the 1,050 cohort (mean [{+-}SD] age 56.9 {+-} 7.4 years), 39 (3.7%) patients were excluded owing to lack of follow-up within our system beyond the initial screening CTC. The remaining 1,011 patients were followed for an average of 4.73 {+-} 1.15 years. One incident colorectal adenocarcinoma represented a crude cancer incidence of 0.2 cancers per 1,000 patient years. EMR revealed 14 additional patients with clinically important GI tumours including: advanced adenomas (n = 11), appendiceal goblet cell carcinoid (n = 1), appendiceal mucinous adenoma (n = 1) and metastatic ileocolonic carcinoid (n = 1). All positive patients including the incident carcinoma are alive at the time of review. Clinically presenting colorectal adenocarcinoma is rare in the 5 years following negative screening CTC, suggesting that current strategies, including non-reporting of diminutive lesions, are appropriate. (orig.)

Five year colorectal cancer outcomes in a large negative CT colonography screening cohort

International Nuclear Information System (INIS)

Kim, David H.; Pooler, B.D.; Pickhardt, Perry J.; Weiss, Jennifer M.

2012-01-01

To assess the 5-year incidence of clinically presenting colorectal cancers following a negative CT colonography (CTC) screening examination, as few patient outcome data regarding a negative CTC screening result exist. Negative CTC screening patients (n = 1,050) in the University of Wisconsin Health system over a 14-month period were included. An electronic medical record (EMR) review was undertaken, encompassing provider, colonoscopy, imaging and histopathology reports. Incident colorectal cancers and other important GI tumours were recorded. Of the 1,050 cohort (mean [±SD] age 56.9 ± 7.4 years), 39 (3.7%) patients were excluded owing to lack of follow-up within our system beyond the initial screening CTC. The remaining 1,011 patients were followed for an average of 4.73 ± 1.15 years. One incident colorectal adenocarcinoma represented a crude cancer incidence of 0.2 cancers per 1,000 patient years. EMR revealed 14 additional patients with clinically important GI tumours including: advanced adenomas (n = 11), appendiceal goblet cell carcinoid (n = 1), appendiceal mucinous adenoma (n = 1) and metastatic ileocolonic carcinoid (n = 1). All positive patients including the incident carcinoma are alive at the time of review. Clinically presenting colorectal adenocarcinoma is rare in the 5 years following negative screening CTC, suggesting that current strategies, including non-reporting of diminutive lesions, are appropriate. (orig.)

CT colonography at low tube potential: using iterative reconstruction to decrease noise

International Nuclear Information System (INIS)

Chang, K.J.; Heisler, M.A.; Mahesh, M.; Baird, G.L.; Mayo-Smith, W.W.

2015-01-01

Aim: To determine the level of iterative reconstruction required to reduce increased image noise associated with low tube potential computed tomography (CT). Materials and methods: Fifty patients underwent CT colonography with a supine scan at 120 kVp and a prone scan at 100 kVp with other scan parameters unchanged. Both scans were reconstructed with filtered back projection (FBP) and increasing levels of adaptive statistical iterative reconstruction (ASiR) at 30%, 60%, and 90%. Mean noise, soft tissue and tagged fluid attenuation, contrast, and contrast-to-noise ratio (CNR) were collected from reconstructions at both 120 and 100 kVp and compared using a generalised linear mixed model. Results: Decreasing tube potential from 120 to 100 kVp significantly increased image noise by 30–34% and tagged fluid attenuation by 120 HU at all ASiR levels (p<0.0001, all measures). Increasing ASiR from 0% (FBP) to 30%, 60%, and 90% resulted in significant decreases in noise and increases in CNR at both tube potentials (p<0.001, all comparisons). Compared to 120 kVp FBP, ASiR greater than 30% at 100 kVp yielded similar or lower image noise. Conclusions: Iterative reconstruction adequately compensates for increased image noise associated with low tube potential imaging while improving CNR. An ASiR level of approximately 50% at 100 kVp yields similar noise to 120 kVp without ASiR. -- Highlights: •Peak kilovoltage (kVp) can be reduced to decrease radiation dose and increase contrast attenuation at a cost of increased image noise. •Utilizing iterative reconstruction can decrease image noise and increase contrast to noise ratio (CNR) independent of kVp. •Iterative reconstruction adequately compensates for increased image noise associated with low dose low kVp imaging while improving CNR. •An ASiR level of approximately 50% at 100 kVp yields similar noise to 120 kVp without ASiR

Trends in CT colonography: bibliometric analysis of the 100 most-cited articles.

Science.gov (United States)

Mohammed, Mohammed Fahim; Chahal, Tejbir; Gong, Bo; Bhulani, Nizar; O'Keefe, Michael; O'Connell, Timothy; Nicolaou, Savvas; Khosa, Faisal

2017-12-01

Our purpose was to identify the top 100 cited articles, which focused on CT colonography (CTC). This list could then be analysed to establish trends in CTC research while also identifying common characteristics of highly cited works. Web of Science search was used to create a database of scientific journals using our search terms. A total of 10,597 articles were returned from this search. Articles were included if they focused on diagnostic imaging, imaging technique, cost-effectiveness analysis, clinical use, patient preference or trends in CTC. Articles were ranked by citation count and screened by two attending radiologists. The following information was collected from each article: database citations, citations per year, year published, journal, authors, department affiliation, study type and design, statistical analysis, sample size, modality and topic. Citations for the top 100 articles ranged from 73 to 1179, and citations per year ranged from 4.5 to 84.21. Articles were published across 22 journals, most commonly Radiology (n = 37) and American Journal of Roentgenology (n = 19). Authors contributed from 1 to 20 articles. 19% of first authors were affiliated with a department other than radiology. Of the 100 articles, the most common topics were imaging technique (n = 40), diagnostic utility of imaging (n = 28) and clinical uses (n = 18). Our study provides intellectual milestones in CTC research, reflecting on the characteristics and quality of published literature. This work also provides the most influential references related to CTC and serves as a guide to the features of a citable paper in this field.

Dry preparation for virtual CT colonography with fecal tagging using water-soluble contrast medium: initial results

International Nuclear Information System (INIS)

Bielen, Didier; Thomeer, Maarten; Vanbeckevoort, Dirk; Marchal, Guy; Kiss, Gabriel; Maes, Frederik; Rutgeerts, Paul

2003-01-01

The purpose of this study was to evaluate the feasibility of a dry bowel preparation, i.e. without laxative fluids, for virtual CT colonography (VCTC), and its impact on patient acceptance compared with conventional colonoscopy (CC). A randomly chosen patient population scheduled for CC (n=11) was first submitted to VCTC after a dry preparation, consisting of low-residue meals combined with a small amount of a iodinated water-soluble contrast medium during each meal 3 days before VCTC. In different colon segments and between different persons, the degree of tagging in VCTC was evaluated and graded. Patient acceptance and future preference were assessed for both preparations as well as for both investigations. The mixing of the contrast with the intestinal content results in contrast impregnated stool, the tagged feces. The degree of fecal tagging was good in the majority of the patients and the colonic segments, especially in the descending colon and sigmoid. Furthermore, patient acceptance and preference were clearly in favour of VCTC compared with CC merely because of the non-invasiveness of the dry preparation. Dry bowel preparation and VCTC is a promising approach towards a patient-friendly colon cancer-screening setup. (orig.)

Is a Double Contrast Barium Enema Necessary in Patients who Undergo a CT Colonography as a Preoperative Work-up?

International Nuclear Information System (INIS)

Lee, Ji Won; Lee, Soon Jin; Choi, Dong Il; Kim, Hee Jung; Chun, Ho Kyung; Yun, Seong Hyeon; Jeon, Yong Hwan; Park, Seung Bae; Kim, Min Ju

2009-01-01

To determine the efficiency of CT colonography (CTC), as compared with the double contrast barium enema (DCBE) for the preoperative work-up of colorectal neoplasms. A total of 39 patients underwent both a CTC and DCBE before surgery. Three abdominal radiologists and three colorectal surgeons retrospectively reviewed virtual double contrast (VDC) and DCBE images, regarding each examination for localization, conspicuity, extent and morphology of neoplasms. We reviewed the radiological reports of the CTC and DCBE for the polyps. In the case of both VDC and DCBE, 40 cancers were detected in 39 patients. According to abdominal radiologists, VDC showed the same ability to identify DCBE for localization of neoplasms (p 0.05). The performance of the CTC is comparable to the DCBE for the localization of main mass and polyps in patients with colorectal neoplasm. Barium enema don't seem to be necessary for patients who undergo a CTC as preoperative work-up

Bowel preparation in CT colonography. Is diet restriction necessary? A randomised trial (DIETSAN)

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Bellini, Davide; De Santis, Domenico; Caruso, Damiano; Rengo, Marco; Biondi, Tommaso; Laghi, Andrea [Rome Univ. ' ' Sapienza' ' (Italy). Dept. of Radiological Sciences, Oncology and Pathology; I.C.O.T. Hospital, Latina (Italy); Ferrari, Riccardo [San Camillo Forlanini Hospital, Rome (Italy). Dept. of Emergency Radiology

2018-01-15

To investigate whether diet restriction affects quality of colon cleansing and patient tolerance during reduced bowel preparation for CT colonography (CTC). Asymptomatic and symptomatic patients were enrolled in this pragmatic, single-centre, randomised trial. All patients were randomly assigned (1:1 ratio, blocks of ten) to receive a reduced bowel preparation and faecal tagging with (Diet-Restriction-Group [DR]) or without (No-Diet-Restriction-Group [NDR]) dietary restriction. Five readers performed a blinded subjective image analysis, by means of 4-point Likert-scales from 0 (highest score) to 3 (worst score). Endpoints were the quality of large bowel cleansing and tolerance to the assigned bowel preparation regimen. The trial is registered at ClinicalTrial.gov (URomLSDBAL1). Ninety-five patients were randomly allocated to treatments (48 in NDR-group, 47 in DR-group). Both groups resulted in optimal colon cleansing. The mean residual stool (0.22, 95%CI 0.00-0.44) and fluid burden (0.39, 95%CI 0.25-0.53) scores for patients in DR-group were similar to those in patients in NDR-group (0.25, 95%CI 0.03-0.47 [p = 0.82] and 0.49, 95%CI 0.30-0.67 [p = 0.38], respectively). Tolerance was significantly better in NDR-group. A reduced bowel preparation in association with faecal tagging and without any dietary restriction demonstrated optimal colon cleansing effectiveness for CTC, providing better patient compliance compared with dietary restriction. (orig.)

Bowel preparation in CT colonography. Is diet restriction necessary? A randomised trial (DIETSAN)

International Nuclear Information System (INIS)

Bellini, Davide; De Santis, Domenico; Caruso, Damiano; Rengo, Marco; Biondi, Tommaso; Laghi, Andrea; Ferrari, Riccardo

2018-01-01

To investigate whether diet restriction affects quality of colon cleansing and patient tolerance during reduced bowel preparation for CT colonography (CTC). Asymptomatic and symptomatic patients were enrolled in this pragmatic, single-centre, randomised trial. All patients were randomly assigned (1:1 ratio, blocks of ten) to receive a reduced bowel preparation and faecal tagging with (Diet-Restriction-Group [DR]) or without (No-Diet-Restriction-Group [NDR]) dietary restriction. Five readers performed a blinded subjective image analysis, by means of 4-point Likert-scales from 0 (highest score) to 3 (worst score). Endpoints were the quality of large bowel cleansing and tolerance to the assigned bowel preparation regimen. The trial is registered at ClinicalTrial.gov (URomLSDBAL1). Ninety-five patients were randomly allocated to treatments (48 in NDR-group, 47 in DR-group). Both groups resulted in optimal colon cleansing. The mean residual stool (0.22, 95%CI 0.00-0.44) and fluid burden (0.39, 95%CI 0.25-0.53) scores for patients in DR-group were similar to those in patients in NDR-group (0.25, 95%CI 0.03-0.47 [p = 0.82] and 0.49, 95%CI 0.30-0.67 [p = 0.38], respectively). Tolerance was significantly better in NDR-group. A reduced bowel preparation in association with faecal tagging and without any dietary restriction demonstrated optimal colon cleansing effectiveness for CTC, providing better patient compliance compared with dietary restriction. (orig.)

Preliminary evaluation of helical CT colonography in detection of colonic diseases compared with double contrast barium enema

International Nuclear Information System (INIS)

Zhai Xiaoli; Zhang Lei; Zhai Renyou; Li Jie; Wang Yajie; Ding Yi

2000-01-01

Objective: To evaluate helical CT colonography in regard to technology principles, limitations, and clinical applications. Methods: Fifty-six patients underwent volume scanning using helical CT. The diseases included adenocarcinoma 39, adenomatous polyp 3, multiple diverticular 7, mucocele of appendix 1, and normal colon 6. All cases had been compared with double contrast barium enema (DCBE), proved by histology except the 6 normal colon and the 7 multiple diverticular. All CTC images were reconstructed using shaded surface display (SSD) on workstation. Then, perspective images such as the ones from DCBE were generated via ray sum. The images could clearly demonstrate the extent and detail of the disorder by using 'CUT' software, 'revolve' function, and zoom. Results: CTC correctly demonstrated 3-5 mm diverticulum, 3 mm ulcer, and 6 mm polyps. Not only show colon straitness clearly, CTC is also very sensitive to demonstrate the stenotic end of masses. In these cases, discovery rate of CTC is 100.0%, the rate of DCBE is 88.6%; CTC is more sensitive than DCBE in cases of tumor nodules. Ray sum can show the boundary of colonic mass extending to both proximal and distal ends, its discovery rate is 62.6%. Accuracy of localization for CTC is 100.0%. Conclusion: CTC is a novel technique for detecting colonic diseases. It is a safe, accurate, and non-invasive means for detection of lesions and is an efficient complement for DCBE. Further development in CTC technique is expected in the future

CAD for CT colonography: toward a preparation-independent scheme

International Nuclear Information System (INIS)

Naeppi, J.

2007-01-01

Computer-aided detection (CAD) systems can be used to automatically detect and display the locations of polyps and masses in computed tomographic colonography (CTC) data for assisting radiologists' image interpretation. Rapid technical advancements over the last few years have established a fundamental CAD scheme for CTC that includes the steps of colon extraction, polyp detection, and false-positive (FP) reduction. Several CAD prototype systems have demonstrated clinically acceptable high polyp detection sensitivity with relatively few FP detections in cathartic CTC, and observer studies have demonstrated the potential benefit of such systems in improving the accuracy and consistency of radiologists' detection performance. Some CAD prototype systems have also demonstrated promising performance in reduced cathartic and non-cathartic CTC. Recent advancements suggest that CAD systems can soon be expected to provide a preparation-independent scheme that can yield consistently high detection sensitivity with moderately low FP rate not only with cathartic CTC protocols but over a wide range of cathartic, reduced cathartic, and non-cathartic CTC protocols. (orig.)

Current status on performance of CT colonography and clinical indications

International Nuclear Information System (INIS)

Laghi, Andrea; Rengo, Marco; Graser, Anno; Iafrate, Franco

2013-01-01

CT colonography (CTC) is a robust and reliable imaging test of the colon. Accuracy for the detection of colorectal cancer (CRC) is as high as conventional colonoscopy (CC). Identification of polyp is size dependent, with large lesions (≥10 mm) accurately detected and small lesions (6–9 mm) identified with moderate to good sensitivity. Recent studies show good sensitivity for the identification of nonpolypoid (flat) lesions as well. Current CTC indications include the evaluation of patients who had undergone a previous incomplete CC or those who are unfit for CC (elderly and frail individuals, patients with underlying severe clinical conditions, or with contraindication to sedation). CTC can also be efficiently used in the assessment of diverticular disease (excluding patients with acute diverticulitis, where the exam should be postponed), before laparoscopic surgery for CRC (to have an accurate localization of the lesion), in the evaluation of colonic involvement in the case of deep pelvic endometriosis (replacing barium enema). CTC is also a safe procedure in patients with colostomy. For CRC screening, CTC should be considered an opportunistic screening test (not available for population, or mass screening) to be offered to asymptomatic average-risk individuals, of both genders, starting at age 50. The use in individuals with positive family history should be discussed with the patient first. Absolute contraindication is to propose CTC for surveillance of genetic syndromes and chronic inflammatory bowel diseases (in particular, ulcerative colitis). The use of CTC in the follow-up after surgery for CRC is achieving interesting evidences despite the fact that literature data are still relatively weak in terms of numerosity of the studied populations. In patients who underwent previous polypectomy CTC cannot be recommended as first test because debate is still open. It is desirable that in the future CTC would be the first-line and only diagnostic test for

Current status on performance of CT colonography and clinical indications

Energy Technology Data Exchange (ETDEWEB)

Laghi, Andrea, E-mail: andrea.laghi@uniroma1.it [Department of Radiological Sciences, Oncology and Pathology Sapienza – Università di Roma, Polo Pontino, I.C.O.T. Hospital, Via Franco Faggiana 43, 04100 Latina (Italy); Rengo, Marco [Department of Radiological Sciences, Oncology and Pathology Sapienza – Università di Roma, Polo Pontino, I.C.O.T. Hospital, Via Franco Faggiana 43, 04100 Latina (Italy); Graser, Anno [InstitutfürKlinische Radiologie, Klinikumder Ludwig-Maximilians-Universität München, Campus Großhadern, Marchioninistr. 15, 81377 München (Germany); Iafrate, Franco [Department of Radiological Sciences, Oncology and Pathology Sapienza – Università di Roma, Policlinico Umberto I, Viale Regina Elena 324, 00161 Rome (Italy)

2013-08-15

CT colonography (CTC) is a robust and reliable imaging test of the colon. Accuracy for the detection of colorectal cancer (CRC) is as high as conventional colonoscopy (CC). Identification of polyp is size dependent, with large lesions (≥10 mm) accurately detected and small lesions (6–9 mm) identified with moderate to good sensitivity. Recent studies show good sensitivity for the identification of nonpolypoid (flat) lesions as well. Current CTC indications include the evaluation of patients who had undergone a previous incomplete CC or those who are unfit for CC (elderly and frail individuals, patients with underlying severe clinical conditions, or with contraindication to sedation). CTC can also be efficiently used in the assessment of diverticular disease (excluding patients with acute diverticulitis, where the exam should be postponed), before laparoscopic surgery for CRC (to have an accurate localization of the lesion), in the evaluation of colonic involvement in the case of deep pelvic endometriosis (replacing barium enema). CTC is also a safe procedure in patients with colostomy. For CRC screening, CTC should be considered an opportunistic screening test (not available for population, or mass screening) to be offered to asymptomatic average-risk individuals, of both genders, starting at age 50. The use in individuals with positive family history should be discussed with the patient first. Absolute contraindication is to propose CTC for surveillance of genetic syndromes and chronic inflammatory bowel diseases (in particular, ulcerative colitis). The use of CTC in the follow-up after surgery for CRC is achieving interesting evidences despite the fact that literature data are still relatively weak in terms of numerosity of the studied populations. In patients who underwent previous polypectomy CTC cannot be recommended as first test because debate is still open. It is desirable that in the future CTC would be the first-line and only diagnostic test for

Computer tomography colonography participation and yield in patients under surveillance for 6-9 mm polyps in a population-based screening trial

NARCIS (Netherlands)

Tutein Nolthenius, Charlotte J.; Boellaard, Thierry N.; de Haan, Margriet C.; Nio, C. Yung; Thomeer, Maarten G. J.; Bipat, Shandra; Montauban van Swijndregt, Alexander D.; van de Vijver, Marc J.; Biermann, Katharina; Kuipers, Ernst J.; Dekker, Evelien; Stoker, Jaap

2016-01-01

Surveillance CT colonography (CTC) is a viable option for 6-9 mm polyps at CTC screening for colorectal cancer. We established participation and diagnostic yield of surveillance and determined overall yield of CTC screening. In an invitational CTC screening trial 82 of 982 participants harboured 6-9

Multi-detector CT-colonography in inflammatory bowel disease: Prospective analysis of CT-findings to high-resolution video colonoscopy

International Nuclear Information System (INIS)

Andersen, Kjel; Vogt, Christoph; Blondin, Dirk; Beck, Andreas; Heinen, Wolfram; Aurich, Volker; Haeussinger, Dieter; Moedder, Ulrich; Cohnen, Mathias

2006-01-01

Aim: Prospective analysis of multi-detector CT-colonography (MDCTC) in patients with inflammatory bowel disease (IBD) compared to high-resolution video-endoscopy (HRVC). Materials and methods: Twenty-one patients (mean age 49.6 years) with Crohn's disease or ulcerative colitis underwent MDCTC (Somatom Volume Zoom, Siemens, Erlangen; 1 mm collimation, Pitch 8, 100 mAs, 120 kVp). HRVC was performed within 2 h after MDCTC. MDCTC was analyzed by two blinded readers. MDCTC-findings including bowel wall alterations and extraintestinal changes were compared to results of HRVC. Results: Over-all-sensitivity was 100% for endoluminal lesions with correct diagnosis of two cancers. Acute and chronic IBD were correctly identified by MDCTC in 63.6%, and 100%, respectively, with a specificity of 75%, and 100%. Sensitivity, specificity, positive and negative predictive values of MDCTC for diagnosis of acute and chronic disease were best for chronic disease. Sensitivity was worst for acute ulcerative colitis and specificity was worst for acute Crohn's disease. Haustral loss was seen only in ulcerative colitis. Pseudopolyps and fistulae were findings exclusive to Crohn's disease. Particularly extraintestinal findings as increased vascularization and local lymphadenopathy correlated well with endoscopic definition of acute disease. Because of the possibly more vulnerable colonic wall in acute inflammatory bowel disease, the air inflation for MDCTC should be performed most carefully to avoid any risk of colonic perforation. Conclusion: MDCTC may help to distinguish between patients with acute and chronic IBD. Especially extraintestinal complications, tumorous as well as pseudo-tumorous lesions can be detected with high sensitivity and specificity

Computer-assisted polyp matching between optical colonoscopy and CT colonography: a phantom study

Science.gov (United States)

Roth, Holger R.; Hampshire, Thomas E.; Helbren, Emma; Hu, Mingxing; Vega, Roser; Halligan, Steve; Hawkes, David J.

2014-03-01

Potentially precancerous polyps detected with CT colonography (CTC) need to be removed subsequently, using an optical colonoscope (OC). Due to large colonic deformations induced by the colonoscope, even very experienced colonoscopists find it difficult to pinpoint the exact location of the colonoscope tip in relation to polyps reported on CTC. This can cause unduly prolonged OC examinations that are stressful for the patient, colonoscopist and supporting staff. We developed a method, based on monocular 3D reconstruction from OC images, that automatically matches polyps observed in OC with polyps reported on prior CTC. A matching cost is computed, using rigid point-based registration between surface point clouds extracted from both modalities. A 3D printed and painted phantom of a 25 cm long transverse colon segment was used to validate the method on two medium sized polyps. Results indicate that the matching cost is smaller at the correct corresponding polyp between OC and CTC: the value is 3.9 times higher at the incorrect polyp, comparing the correct match between polyps to the incorrect match. Furthermore, we evaluate the matching of the reconstructed polyp from OC with other colonic endoluminal surface structures such as haustral folds and show that there is a minimum at the correct polyp from CTC. Automated matching between polyps observed at OC and prior CTC would facilitate the biopsy or removal of true-positive pathology or exclusion of false-positive CTC findings, and would reduce colonoscopy false-negative (missed) polyps. Ultimately, such a method might reduce healthcare costs, patient inconvenience and discomfort.

Burden of waiting for surveillance CT colonography in patients with screen-detected 6-9 mm polyps

Energy Technology Data Exchange (ETDEWEB)

Tutein Nolthenius, Charlotte J. [University of Amsterdam, Department of Radiology, Academic Medical Center, PO Box 22700, Amsterdam (Netherlands); Onze Lieve Vrouwe Gasthuis, Department of Radiology, Amsterdam (Netherlands); Boellaard, Thierry N.; Nio, C.Y.; Bipat, Shandra; Stoker, Jaap [University of Amsterdam, Department of Radiology, Academic Medical Center, PO Box 22700, Amsterdam (Netherlands); Haan, Margriet C. de [Meander Medical Center, Department of Radiology, Amersfoort (Netherlands); Thomeer, Maarten G.J. [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Montauban van Swijndregt, Alexander D. [Onze Lieve Vrouwe Gasthuis, Department of Radiology, Amsterdam (Netherlands); Essink-Bot, Marie-Louise [University of Amsterdam, Public Health, Academic Medical Center, PO Box 22700, Amsterdam (Netherlands); Kuipers, Ernst J. [Erasmus University Medical Center, Gastroenterology and Hepatology, Rotterdam (Netherlands); Erasmus University Medical Center, Internal medicine, Rotterdam (Netherlands); Dekker, Evelien [University of Amsterdam, Gastroenterology and Hepatology, Academic Medical Center, PO Box 22700, Amsterdam (Netherlands)

2016-11-15

We assessed the burden of waiting for surveillance CT colonography (CTC) performed in patients having 6-9 mm colorectal polyps on primary screening CTC. Additionally, we compared the burden of primary and surveillance CTC. In an invitational population-based CTC screening trial, 101 persons were diagnosed with <3 polyps 6-9 mm, for which surveillance CTC after 3 years was advised. Validated questionnaires regarding expected and perceived burden (5-point Likert scales) were completed before and after index and surveillance CTC, also including items on burden of waiting for surveillance CTC. McNemar's test was used for comparison after dichotomization. Seventy-eight (77 %) of 101 invitees underwent surveillance CTC, of which 66 (85 %) completed the expected and 62 (79 %) the perceived burden questionnaire. The majority of participants (73 %) reported the experience of waiting for surveillance CTC as 'never' or 'only sometimes' burdensome. There was almost no difference in expected and perceived burden between surveillance and index CTC. Waiting for the results after the procedure was significantly more burdensome for surveillance CTC than for index CTC (23 vs. 8 %; p = 0.012). Waiting for surveillance CTC after primary CTC screening caused little or no burden for surveillance participants. In general, the burden of surveillance and index CTC were comparable. (orig.)

Computed tomographic colonography (CTC); colorectal cancer diagnosis with CTC in an Auckland population

International Nuclear Information System (INIS)

Moore, Helen; Dodd, Nicholas

2013-01-01

To determine the sensitivity of computed tomographic colonography (CTC) in the detection of colorectal cancer in our population and evaluate the reasons why these lesions may be missed on CTC. All patients who underwent CTC in the 65-month period from 1 January 2004 to 1 July 2009 were included in the analysis. Demographic data and CTC findings were recorded, according to the CT Colonography Reporting and Data System. Data were cross-matched with the National Cancer Registry results for colorectal cancer cases between 1 January 2004 and 1 October 2009, 3 months longer to include any delayed diagnoses. There were 2026 consecutive CTC patients, comprising 52.6% female, average age of 60 years; range 19–87. Approximately 84% were symptomatic. There were 45 confirmed colorectal cancers among this patient group in the National Cancer Registry during the relevant time period compared with 43 suspected cancers on CTC, giving a miss rate of 2 of 45, or 4.4%. The sensitivity of 95% for CTC in the detection of colorectal cancer compares favourably with the published national and international data.

CT colonography training for radiographers - a formal evaluation

International Nuclear Information System (INIS)

Haycock, A.; Burling, D.; Wylie, P.; Muckian, J.; Ilangovan, R.; Thomas-Gibson, S.

2010-01-01

Aims: To evaluate the efficacy of a new intensive 'hands-on' course designed to train small teams of radiographers in computed tomography colonography (CTC) technique and initial interpretation for patient triage. Materials and methods: The course comprised small-group lectures, active participation in the daily CTC service with practical technique and image interpretation training by experienced radiologists and radiographers. Evaluation was by assessment of knowledge using randomized sets of multiple choice questions (MCQ; pre/post-course), practical technique using checklists and expert global scores, and interpretation performance outcomes using randomized pre/post-course test datasets (five validated CTC examinations each). Paired t-tests were used to investigate change in performance for MCQ score and interpretation accuracy. Results: Thirteen courses with 49 participants were evaluated over 2 years. Practical skills were high, with mean (SD) checklist scores of 14/15 (0.85) and global scores of 26/30 (2.3). MCQ scores increased significantly from a mean of 59% pre-course to 69% post-course, p 10 mm) detection rates also improved significantly from 49% to 60%, p = 0.002. Conclusion: Structured training in CTC can significantly improve knowledge and interpretation skills of radiographers, while assessing safe procedural performance. Implementation of similar programmes nationally may help reduce performance gaps between centres.

Your Radiologist Explains CT Colonography

Medline Plus

Full Text Available ... is used to screen the large intestine or colon for cancer and growths called polyps. This procedure uses low-dose CT or CAT scanning to produce pictures of the colon and the rectum. During the examination, a small ...

A robust and efficient approach to detect 3D rectal tubes from CT colonography

Energy Technology Data Exchange (ETDEWEB)

Yang Xiaoyun; Slabaugh, Greg [Medicsight PLC, Kensington Centre, 66 Hammersmith Road, London (United Kingdom)

2011-11-15

Purpose: The rectal tube (RT) is a common source of false positives (FPs) in computer-aided detection (CAD) systems for CT colonography. A robust and efficient detection of RT can improve CAD performance by eliminating such ''obvious'' FPs and increase radiologists' confidence in CAD. Methods: In this paper, we present a novel and robust bottom-up approach to detect the RT. Probabilistic models, trained using kernel density estimation on simple low-level features, are employed to rank and select the most likely RT tube candidate on each axial slice. Then, a shape model, robustly estimated using random sample consensus (RANSAC), infers the global RT path from the selected local detections. Subimages around the RT path are projected into a subspace formed from training subimages of the RT. A quadratic discriminant analysis (QDA) provides a classification of a subimage as RT or non-RT based on the projection. Finally, a bottom-top clustering method is proposed to merge the classification predictions together to locate the tip position of the RT. Results: Our method is validated using a diverse database, including data from five hospitals. On a testing data with 21 patients (42 volumes), 99.5% of annotated RT paths have been successfully detected. Evaluated with CAD, 98.4% of FPs caused by the RT have been detected and removed without any loss of sensitivity. Conclusions: The proposed method demonstrates a high detection rate of the RT path, and when tested in a CAD system, reduces FPs caused by the RT without the loss of sensitivity.

A robust and efficient approach to detect 3D rectal tubes from CT colonography

International Nuclear Information System (INIS)

Yang Xiaoyun; Slabaugh, Greg

2011-01-01

Purpose: The rectal tube (RT) is a common source of false positives (FPs) in computer-aided detection (CAD) systems for CT colonography. A robust and efficient detection of RT can improve CAD performance by eliminating such ''obvious'' FPs and increase radiologists' confidence in CAD. Methods: In this paper, we present a novel and robust bottom-up approach to detect the RT. Probabilistic models, trained using kernel density estimation on simple low-level features, are employed to rank and select the most likely RT tube candidate on each axial slice. Then, a shape model, robustly estimated using random sample consensus (RANSAC), infers the global RT path from the selected local detections. Subimages around the RT path are projected into a subspace formed from training subimages of the RT. A quadratic discriminant analysis (QDA) provides a classification of a subimage as RT or non-RT based on the projection. Finally, a bottom-top clustering method is proposed to merge the classification predictions together to locate the tip position of the RT. Results: Our method is validated using a diverse database, including data from five hospitals. On a testing data with 21 patients (42 volumes), 99.5% of annotated RT paths have been successfully detected. Evaluated with CAD, 98.4% of FPs caused by the RT have been detected and removed without any loss of sensitivity. Conclusions: The proposed method demonstrates a high detection rate of the RT path, and when tested in a CAD system, reduces FPs caused by the RT without the loss of sensitivity.

Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

Energy Technology Data Exchange (ETDEWEB)

Lim, Hyun Kyong; Lee, Kyoung Ho; Kim, So Yeon; Kim, Young Hoon [Seoul National University Bundang Hospital, Department of Radiology, Seongnam-si, Gyeonggi-do (Korea, Republic of); Seoul National University College of Medicine, Seoul National University Medical Research Center, Institute of Radiation Medicine, Bundang (Korea, Republic of); Kim, Kil Joong [Seoul National University College of Medicine, Department of Radiation Applied Life Science, Seoul (Korea, Republic of); Kim, Bohyoung; Lee, Hyunna [Seoul National University, School of Computer Science and Engineering, Seoul (Korea, Republic of); Park, Seong Ho [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Yanof, Jeffrey H. [Philips Healthcare, CT Clinical Science, Cleveland, OH (United States); Hwang, Seung-sik [Inha University School of Medicine, Department of Social and Preventive Medicine, Incheon (Korea, Republic of)

2011-02-15

To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique. The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDI{sub vol}) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDI{sub vol} and the effect of ATT on image noise while adjusting for other variables including abdominal circumference. CTDI{sub vol} varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI{sub vol} and ATT (p = 0.61). ATT did not significantly affect CTDI{sub vol} (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI{sub vol} (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38. The amount of stool and fluid tagging does not significantly affect radiation exposure. (orig.)

Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

International Nuclear Information System (INIS)

Lim, Hyun Kyong; Lee, Kyoung Ho; Kim, So Yeon; Kim, Young Hoon; Kim, Kil Joong; Kim, Bohyoung; Lee, Hyunna; Park, Seong Ho; Yanof, Jeffrey H.; Hwang, Seung-sik

2011-01-01

To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique. The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDI vol ) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDI vol and the effect of ATT on image noise while adjusting for other variables including abdominal circumference. CTDI vol varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI vol and ATT (p = 0.61). ATT did not significantly affect CTDI vol (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI vol (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38. The amount of stool and fluid tagging does not significantly affect radiation exposure. (orig.)

Your Radiologist Explains CT Colonography

Medline Plus

Full Text Available ... commonly known, virtual colonoscopy. Virtual colonoscopy is a diagnostic imaging test that is used to screen the large intestine or colon for cancer and growths called polyps. This procedure uses low-dose CT or CAT scanning ... Disorders Video: The Basketball Game: An ...

Vascular map combined with CT colonography for evaluating candidates for laparoscopic colorectal surgery

International Nuclear Information System (INIS)

Flor, Nicola; Ceretti, Andrea Pisani; Maroni, Nirvana; Opocher, Enrico; Cornalba, Gianpaolo; Campari, Alessandro; Ravelli, Anna; Lombardi, Maria Antonietta

2015-01-01

Contrast-enhanced computed tomography colonography (CE-CTC) is a useful guide for the laparoscopic surgeon to avoid incorrectly removing the colonic segment and the failure to diagnose of synchronous colonic and extra-colonic lesions. Lymph node dissection and vessel ligation under a laparoscopic approach can be time-consuming and can damage vessels and organs. Moreover, mesenteric vessels have extreme variations in terms of their courses and numbers. We describe the benefit of using an abdominal vascular map created by CE-CTC in laparoscopic colorectal surgery candidates. We describe patients with different diseases (colorectal cancer, diverticular disease, and inflammatory bowel disease) who underwent CE-CTC just prior to laparoscopic surgery

Vascular map combined with CT colonography for evaluating candidates for laparoscopic colorectal surgery

Energy Technology Data Exchange (ETDEWEB)

Flor, Nicola; Ceretti, Andrea Pisani; Maroni, Nirvana; Opocher, Enrico; Cornalba, Gianpaolo [Azienda Ospedaliera San Paolo, Milan (Italy); Campari, Alessandro; Ravelli, Anna; Lombardi, Maria Antonietta [University degli Studi di Milano, Milan (Italy)

2015-08-15

Contrast-enhanced computed tomography colonography (CE-CTC) is a useful guide for the laparoscopic surgeon to avoid incorrectly removing the colonic segment and the failure to diagnose of synchronous colonic and extra-colonic lesions. Lymph node dissection and vessel ligation under a laparoscopic approach can be time-consuming and can damage vessels and organs. Moreover, mesenteric vessels have extreme variations in terms of their courses and numbers. We describe the benefit of using an abdominal vascular map created by CE-CTC in laparoscopic colorectal surgery candidates. We describe patients with different diseases (colorectal cancer, diverticular disease, and inflammatory bowel disease) who underwent CE-CTC just prior to laparoscopic surgery.

Evidence-based investigation of the influence of computer-aided detection of polyps on screening of colon cancer with CT colonography

International Nuclear Information System (INIS)

Yoshida, Hiroyuki

2008-01-01

Computed tomographic colonography (CTC), also known as virtual colonoscopy, is a CT examination of the colon for colorectal neoplasms. Recent large-scale clinical trials have demonstrated that CTC yields sensitivity comparable to optical colonoscopy in the detection of clinically significant polyps in a screening population, making CTC a promising technique for screening of colon cancer. For CTC to be a clinically practical means of screening, it must reliably and consistently detect polyps with high accuracy. However, high-level expertise is required to interpret the resulting CT images to find polyps, resulting in variable diagnostic accuracy among radiologists in the detection of polyps. A key technology to overcome this problem and to bring CTC to prime time for screening of colorectal cancer is computer-aided detection (CAD) of polyps. CAD automatically detects the locations of suspicious polyps in CTC images and presents them to radiologists. CAD has the potential to increase diagnostic performance in the detection of polyps as well as to reduce variability of the diagnostic accuracy among radiologists. This paper presents an evidence-based investigation of the influence of CAD on screening of colon cancer with CTC by describing the benefits of using CAD in the diagnosis of CTC, the fundamental CAD scheme for the detection of polyps in CTC, its detection performance, the effect on the improvement of detection performance, as well as the current and future challenges in CAD. (author)

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

International Nuclear Information System (INIS)

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

2002-01-01

Automation in colorectal mass detection is achieved as soon as the voxels representing colorectal masses can be automatically segmented. We tested the Hounsfield (HU) value in intensely contrast enhanced high-resolution CT colonography for automated segmentation of colorectal masses in 18 patients with 35 polyps (28<10 mm, 7 ≥10 mm) and 7 carcinomas. Mean HU values of the colonic wall and masses were determined to deduce a gradient threshold for a segmentation process, which encodes the voxels bordering the colonic lumen with a colour ranging in intensity from 0 to 100% according to the selected gradient threshold range in the volume rendering. The results of the automated segmentation process were superimposed on a virtual double contrast and endoscopic display and validated through correlation with morphology. Mean HU values and their standard deviations for the colonic wall, polyps <10 mm, polyps ≥10 mm and carcinomas were 63±24, 154±38, 116±41 and 108±29 HU, respectively. A gradient threshold ranging from 90 to 160 HU resulted in colour pools in 6 of 7 of polyps ≥10 mm, and 6 of 7 carcinomas that were significant enough to prospectively guide the reader's attention to these masses. Due to the superposition of ''false-positive'' voxels in the projection view, the virtual endoscopic perspective was superior to the virtual double contrast display for controlling the segmentation results. The HU value is promising for automated segmentation of colorectal masses but needs to be combined with morphological parameters to render automated colorectal mass detection more accurate. Further refinements of the method with subsequent analysis of its accuracy, as well as analogue studies with contrast-enhanced MRI, appear warranted. More information at http://www.multiorganscreening.org (orig.)

Max-AUC feature selection in computer-aided detection of polyps in CT colonography.

Science.gov (United States)

Xu, Jian-Wu; Suzuki, Kenji

2014-03-01

We propose a feature selection method based on a sequential forward floating selection (SFFS) procedure to improve the performance of a classifier in computerized detection of polyps in CT colonography (CTC). The feature selection method is coupled with a nonlinear support vector machine (SVM) classifier. Unlike the conventional linear method based on Wilks' lambda, the proposed method selected the most relevant features that would maximize the area under the receiver operating characteristic curve (AUC), which directly maximizes classification performance, evaluated based on AUC value, in the computer-aided detection (CADe) scheme. We presented two variants of the proposed method with different stopping criteria used in the SFFS procedure. The first variant searched all feature combinations allowed in the SFFS procedure and selected the subsets that maximize the AUC values. The second variant performed a statistical test at each step during the SFFS procedure, and it was terminated if the increase in the AUC value was not statistically significant. The advantage of the second variant is its lower computational cost. To test the performance of the proposed method, we compared it against the popular stepwise feature selection method based on Wilks' lambda for a colonic-polyp database (25 polyps and 2624 nonpolyps). We extracted 75 morphologic, gray-level-based, and texture features from the segmented lesion candidate regions. The two variants of the proposed feature selection method chose 29 and 7 features, respectively. Two SVM classifiers trained with these selected features yielded a 96% by-polyp sensitivity at false-positive (FP) rates of 4.1 and 6.5 per patient, respectively. Experiments showed a significant improvement in the performance of the classifier with the proposed feature selection method over that with the popular stepwise feature selection based on Wilks' lambda that yielded 18.0 FPs per patient at the same sensitivity level.

CT colonography training for radiographers - a formal evaluation

Energy Technology Data Exchange (ETDEWEB)

Haycock, A. [Intestinal Imaging Centre and Wolfson Unit for Endoscopy, St Mark' s Hospital, Imperial College London, London (United Kingdom); Burling, D., E-mail: burlingdavid@yahoo.co.u [Intestinal Imaging Centre and Wolfson Unit for Endoscopy, St Mark' s Hospital, Imperial College London, London (United Kingdom); Wylie, P.; Muckian, J.; Ilangovan, R.; Thomas-Gibson, S. [Intestinal Imaging Centre and Wolfson Unit for Endoscopy, St Mark' s Hospital, Imperial College London, London (United Kingdom)

2010-12-15

Aims: To evaluate the efficacy of a new intensive 'hands-on' course designed to train small teams of radiographers in computed tomography colonography (CTC) technique and initial interpretation for patient triage. Materials and methods: The course comprised small-group lectures, active participation in the daily CTC service with practical technique and image interpretation training by experienced radiologists and radiographers. Evaluation was by assessment of knowledge using randomized sets of multiple choice questions (MCQ; pre/post-course), practical technique using checklists and expert global scores, and interpretation performance outcomes using randomized pre/post-course test datasets (five validated CTC examinations each). Paired t-tests were used to investigate change in performance for MCQ score and interpretation accuracy. Results: Thirteen courses with 49 participants were evaluated over 2 years. Practical skills were high, with mean (SD) checklist scores of 14/15 (0.85) and global scores of 26/30 (2.3). MCQ scores increased significantly from a mean of 59% pre-course to 69% post-course, p < 0.001. Correct classification of CTC examination improved significantly from a mean of 55% pre-course to 71% post-course, p < 0.001. Cancer and large polyp (>10 mm) detection rates also improved significantly from 49% to 60%, p = 0.002. Conclusion: Structured training in CTC can significantly improve knowledge and interpretation skills of radiographers, while assessing safe procedural performance. Implementation of similar programmes nationally may help reduce performance gaps between centres.

Whole-body CT. Spiral and multislice CT. 2. tot. rev. and enl. ed.; Ganzkoerper-Computertomographie. Spiral- und Multislice-CT

Energy Technology Data Exchange (ETDEWEB)

Prokop, M.; Galanski, M.; Schaefer-Prokop, C.; Molen, A.J. van der

2007-07-01

Spiral and multidetector techniques have improved the diagnostic possibilities of CT, so that image analysis and interpretation have become increasingly complex. This book represents the current state of the art in CT imaging, including the most recent technical scanner developments. The second edition comprises the current state of knowledge in cT imaging. There are new chapters on image processing, application of contrasting agents and radiation dose. All organ-specific pathological findings are discussed in full. There are hints for optimum use and interpretation of CT, including CT angiography, CT colonography, CT-IVPL, and 3D imaging. There is an introduction to cardio-CT, from calcium scoring and CTA of the coronary arteries to judgement of cardiac morphology. There are detailed scan protocols with descriptions of how to go about parameter selection. Practical hints are given for better image quality and lower radiation exposure of patients, guidelines for patient preparation and complication management, and more than 1900 images in optimum RRR quality. (orig.)

Deep learning of contrast-coated serrated polyps for computer-aided detection in CT colonography

Science.gov (United States)

Näppi, Janne J.; Pickhardt, Perry; Kim, David H.; Hironaka, Toru; Yoshida, Hiroyuki

2017-03-01

Serrated polyps were previously believed to be benign lesions with no cancer potential. However, recent studies have revealed a novel molecular pathway where also serrated polyps can develop into colorectal cancer. CT colonography (CTC) can detect serrated polyps using the radiomic biomarker of contrast coating, but this requires expertise from the reader and current computer-aided detection (CADe) systems have not been designed to detect the contrast coating. The purpose of this study was to develop a novel CADe method that makes use of deep learning to detect serrated polyps based on their contrast-coating biomarker in CTC. In the method, volumetric shape-based features are used to detect polyp sites over soft-tissue and fecal-tagging surfaces of the colon. The detected sites are imaged using multi-angular 2D image patches. A deep convolutional neural network (DCNN) is used to review the image patches for the presence of polyps. The DCNN-based polyp-likelihood estimates are merged into an aggregate likelihood index where highest values indicate the presence of a polyp. For pilot evaluation, the proposed DCNN-CADe method was evaluated with a 10-fold cross-validation scheme using 101 colonoscopy-confirmed cases with 144 biopsy-confirmed serrated polyps from a CTC screening program, where the patients had been prepared for CTC with saline laxative and fecal tagging by barium and iodine-based diatrizoate. The average per-polyp sensitivity for serrated polyps >=6 mm in size was 93+/-7% at 0:8+/-1:8 false positives per patient on average. The detection accuracy was substantially higher that of a conventional CADe system. Our results indicate that serrated polyps can be detected automatically at high accuracy in CTC.

Multi-detector row CT colonography: effect of collimation, pitch, and orientation on polyp detection in a human colectomy specimen.

Science.gov (United States)

Taylor, Stuart A; Halligan, Steve; Bartram, Clive I; Morgan, Paul R; Talbot, Ian C; Fry, Nicola; Saunders, Brian P; Khosraviani, Kirosh; Atkin, Wendy

2003-10-01

To investigate the effects of orientation, collimation, pitch, and tube current setting on polyp detection at multi-detector row computed tomographic (CT) colonography and to determine the optimal combination of scanning parameters for screening. A colectomy specimen containing 117 polyps of different sizes was insufflated and imaged with a multi-detector row CT scanner at various collimation (1.25 and 2.5 mm), pitch (3 and 6), and tube current (50, 100, and 150 mA) settings. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal surface renderings from the 12 resultant data sets were examined by one observer for the presence and conspicuity of polyps. The results were analyzed with Poisson regression and logistic regression to determine the effects of scanning parameters and of specimen orientation on polyp detection. The percentage of polyps that were detected significantly increased when collimation (P =.008) and table feed (P =.03) were decreased. Increased tube current resulted in improved detection only of polyps with a diameter of less than 5 mm. Polyps of less than 5 mm were optimally depicted with a collimation of 1.25 mm, a pitch of 3, and a tube current setting of 150 mA; polyps with a diameter greater than 5 mm were adequately depicted with 1.25-mm collimation and with either pitch setting and any of the three tube current settings. Small polyps in the transverse segment (positioned at a 90 degrees angle to the z axis of scanning) were significantly less visible than those in parallel or oblique orientations (P detector row CT is highly dependent on collimation, pitch, and, to a lesser extent, tube current. Collimation of 1.25 mm, combined with pitch of 6 and tube current of 50 mA, provides for reliable detection of polyps 5 mm or larger while limiting the effective radiation dose. Polyps smaller than 5 mm, however, may be poorly depicted with use of these settings in the transverse colon. Copyright RSNA, 2003

Whole-body CT. Spiral and multislice CT. 2. tot. rev. and enl. ed.

International Nuclear Information System (INIS)

Prokop, M.; Galanski, M.; Schaefer-Prokop, C.; Molen, A.J. van der

2007-01-01

Spiral and multidetector techniques have improved the diagnostic possibilities of CT, so that image analysis and interpretation have become increasingly complex. This book represents the current state of the art in CT imaging, including the most recent technical scanner developments. The second edition comprises the current state of knowledge in cT imaging. There are new chapters on image processing, application of contrasting agents and radiation dose. All organ-specific pathological findings are discussed in full. There are hints for optimum use and interpretation of CT, including CT angiography, CT colonography, CT-IVPL, and 3D imaging. There is an introduction to cardio-CT, from calcium scoring and CTA of the coronary arteries to judgement of cardiac morphology. There are detailed scan protocols with descriptions of how to go about parameter selection. Practical hints are given for better image quality and lower radiation exposure of patients, guidelines for patient preparation and complication management, and more than 1900 images in optimum RRR quality. (orig.)

Business plan to establish a CT colonography service.

Science.gov (United States)

Fajardo, Laurie L; Hurley, James P; Brown, Bruce P; Summers, Robert W; McDaniel, R Donald

2006-03-01

The authors describe the University of Iowa Department of Radiology's business planning process to initiate a new service in computed tomographic colonography (CTC). Also known as virtual colonoscopy, CTC is a noninvasive technology that offers less risk, and potentially similar sensitivity and specificity, than conventional optical colonoscopy (OC). Although not currently covered by all insurance payers, about a year ago, the Centers for Medicare and Medicaid Services instituted temporary Current Procedural Terminology codes (Category III) for CTC. In locales where the procedure is not covered by insurers, it is likely to be sought by patients willing to pay out of pocket to undergo noninvasive cancer screening as an alternative to OC. Thus, CTC could become the preferred method of colon cancer surveillance by insurance providers in the near future. In developing the business plan, the authors reviewed pertinent scientific and clinical data to evaluate the need for and efficacy of CTC. Local market data were used to estimate patient and procedure volumes and utilization. The authors modeled financial expectations with respect to return on investment on the basis of recently reported models specific to CTC, resource requirements, and the operational impact of the new service on existing hospital and departmental clinical functions. Because there are few local providers of CTC in the authors' region, the business plan also included a publicity campaign and plan to market the new service, stimulate general public interest early, and differentiate the program as a leader in applying this unique new technology to promote cancer screening. Finally, the planning committee acknowledged and accommodated needs specific to the missions of an academic medical center with respect to research and education in designing the new service.

Computed tomography colonography versus colonoscopy for the diagnosis of colorectal cancer: a systematic review and meta-analysis

Directory of Open Access Journals (Sweden)

Duarte RB

2018-02-01

Full Text Available Ralph B Duarte, Wanderley M Bernardo, Christiano M Sakai, Gustavo LR Silva, Hugo G Guedes, Rogerio Kuga, Edson Ide, Robson K Ishida, Paulo Sakai, Eduardo GH de Moura Gastrointestinal Endoscopy Unit of Hospital das Clínicas of São Paulo University Medical School, São Paulo, SP, Brazil Abstract: Colorectal cancer (CRC is a significant cause of morbidity and mortality. Optical colonoscopy (OC is the first choice of investigation for assessing the state of the colon and it is excellent for CRC screening. Newer technologies such as computed tomography colonography (CTC may also be useful in CRC screening. This systematic review compares the benefits of CTC and OC for CRC screening. This review includes all the available randomized clinical trials comparing CTC and OC for CRC screening in asymptomatic patients. Three studies were included in the systematic review and were submitted for meta-analysis. In the analysis of participation rates, only 2,333 of 8,104 (29% patients who were invited for screening underwent the CTC, and only 1,486 of the 7,310 (20% patients who were invited for screening underwent OC. The absolute risk difference in participation rate in the two procedures was 0.1 (95% CI, 0.05–0.14 in favor of CTC. In the analysis of advanced colorectal neoplasia (ACN detection rates, 2,357 patients undergoing CTC and 1,524 patients undergoing OC were included. Of these, 135 patients (5.7% who underwent a CTC and 130 patients (8.5% who underwent an OC were diagnosed with ACN. The absolute risk difference in ACN detection rate in the two procedure types was -0.02 (with a 95% CI between -0.04 and -0.00 in favor of OC. CTC is an option for CRC screening in asymptomatic patients. However, as CTC was inferior in detecting ACN, it should not replace OC, which remains the gold standard. Keywords: computed tomography colonography, colonography, CT colonography, virtual colonoscopy, colonoscopy, colorectal neoplasm, colorectal cancer, colorectal

An improved high order texture features extraction method with application to pathological diagnosis of colon lesions for CT colonography

Science.gov (United States)

Song, Bowen; Zhang, Guopeng; Lu, Hongbing; Wang, Huafeng; Han, Fangfang; Zhu, Wei; Liang, Zhengrong

2014-03-01

Differentiation of colon lesions according to underlying pathology, e.g., neoplastic and non-neoplastic, is of fundamental importance for patient management. Image intensity based textural features have been recognized as a useful biomarker for the differentiation task. In this paper, we introduce high order texture features, beyond the intensity, such as gradient and curvature, for that task. Based on the Haralick texture analysis method, we introduce a virtual pathological method to explore the utility of texture features from high order differentiations, i.e., gradient and curvature, of the image intensity distribution. The texture features were validated on database consisting of 148 colon lesions, of which 35 are non-neoplastic lesions, using the random forest classifier and the merit of area under the curve (AUC) of the receiver operating characteristics. The results show that after applying the high order features, the AUC was improved from 0.8069 to 0.8544 in differentiating non-neoplastic lesion from neoplastic ones, e.g., hyperplastic polyps from tubular adenomas, tubulovillous adenomas and adenocarcinomas. The experimental results demonstrated that texture features from the higher order images can significantly improve the classification accuracy in pathological differentiation of colorectal lesions. The gain in differentiation capability shall increase the potential of computed tomography (CT) colonography for colorectal cancer screening by not only detecting polyps but also classifying them from optimal polyp management for the best outcome in personalized medicine.

The effect of computer-aided detection markers on visual search and reader performance during concurrent reading of CT colonography

International Nuclear Information System (INIS)

Helbren, Emma; Taylor, Stuart A.; Fanshawe, Thomas R.; Mallett, Susan; Phillips, Peter; Boone, Darren; Gale, Alastair; Altman, Douglas G.; Manning, David; Halligan, Steve

2015-01-01

We aimed to identify the effect of computer-aided detection (CAD) on visual search and performance in CT Colonography (CTC) of inexperienced and experienced readers. Fifteen endoluminal CTC examinations were recorded, each with one polyp, and two videos were generated, one with and one without a CAD mark. Forty-two readers (17 experienced, 25 inexperienced) interpreted the videos during infrared visual search recording. CAD markers and polyps were treated as regions of interest in data processing. This multi-reader, multi-case study was analysed using multilevel modelling. CAD drew readers' attention to polyps faster, accelerating identification times: median 'time to first pursuit' was 0.48 s (IQR 0.27 to 0.87 s) with CAD, versus 0.58 s (IQR 0.35 to 1.06 s) without. For inexperienced readers, CAD also held visual attention for longer. All visual search metrics used to assess visual gaze behaviour demonstrated statistically significant differences when ''with'' and ''without'' CAD were compared. A significant increase in the number of correct polyp identifications across all readers was seen with CAD (74 % without CAD, 87 % with CAD; p < 0.001). CAD significantly alters visual search and polyp identification in readers viewing three-dimensional endoluminal CTC. For polyp and CAD marker pursuit times, CAD generally exerted a larger effect on inexperienced readers. (orig.)

The effect of computer-aided detection markers on visual search and reader performance during concurrent reading of CT colonography

Energy Technology Data Exchange (ETDEWEB)

Helbren, Emma; Taylor, Stuart A. [University College London, Centre for Medical Imaging, London (United Kingdom); Fanshawe, Thomas R.; Mallett, Susan [University of Oxford, Nuffield Department of Primary Care Health Sciences, Oxford (United Kingdom); Phillips, Peter [University of Cumbria, Health and Medical Sciences Group, Lancaster (United Kingdom); Boone, Darren [Colchester Hospital University NHS Foundation Trust and Anglia University, Colchester (United Kingdom); Gale, Alastair [Loughborough University, Applied Vision Research Centre, Loughborough (United Kingdom); Altman, Douglas G. [University of Oxford, Centre for Statistics in Medicine, Oxford (United Kingdom); Manning, David [Lancaster University, Lancaster Medical School, Faculty of Health and Medicine, Lancaster (United Kingdom); Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College Hospital, Gastrointestinal Radiology, University College London, Centre for Medical Imaging, Podium Level 2, London, NW1 2BU (United Kingdom)

2015-06-01

We aimed to identify the effect of computer-aided detection (CAD) on visual search and performance in CT Colonography (CTC) of inexperienced and experienced readers. Fifteen endoluminal CTC examinations were recorded, each with one polyp, and two videos were generated, one with and one without a CAD mark. Forty-two readers (17 experienced, 25 inexperienced) interpreted the videos during infrared visual search recording. CAD markers and polyps were treated as regions of interest in data processing. This multi-reader, multi-case study was analysed using multilevel modelling. CAD drew readers' attention to polyps faster, accelerating identification times: median 'time to first pursuit' was 0.48 s (IQR 0.27 to 0.87 s) with CAD, versus 0.58 s (IQR 0.35 to 1.06 s) without. For inexperienced readers, CAD also held visual attention for longer. All visual search metrics used to assess visual gaze behaviour demonstrated statistically significant differences when ''with'' and ''without'' CAD were compared. A significant increase in the number of correct polyp identifications across all readers was seen with CAD (74 % without CAD, 87 % with CAD; p < 0.001). CAD significantly alters visual search and polyp identification in readers viewing three-dimensional endoluminal CTC. For polyp and CAD marker pursuit times, CAD generally exerted a larger effect on inexperienced readers. (orig.)

Fecal-tagging CT colonography with structure-analysis electronic cleansing for detection of colorectal flat lesions

International Nuclear Information System (INIS)

Xu, Yonghua; Cai, Wenli; Nappi, Janne; Yoshida, Hiro

2012-01-01

Purpose: To evaluate the feasibility and sensitivity of the 3D-reading of fecal-tagging CT colonography (CTC) with a novel structure-analysis electronic cleansing (SAEC) in detecting colorectal flat lesions in comparison with a cleansed 3D reading with Viatronix V3D Colon system (V3D) and primary uncleansed 2D reading (2D). Materials and methods: Forty CTC cases with flat lesions were retrospectively observed. The Subjects from a multicenter clinical trial underwent cathartic bowel preparation with orally administrated barium-based fecal-tagging. Sixty-nine flat lesions were confirmed using colonoscopy and histopathology as a reference standard. The results from SAEC reading were compared with those of prospective V3D and 2D readings. Results: Overall detection sensitivity with SAEC was 52% (36/69), which was statistically higher than that of 32% (22/69) and 29% (20/69) with V3D and 2D readings, respectively (p < 0.05). The sensitivities in detecting not-on-fold flat lesions were 63% (24/38), 45% (17/38), and 42% (16/38) with SAEC, V3D, and 2D readings, respectively; whereas those of on-fold flat lesions were 39% (12/31), 16% (5/31), and 13% (4/31), respectively. None of the eight flat lesions (2-9 mm) at cecum was detected by any of the three reading methods. Excluding the flat lesions at cecum, the sensitivity with SAEC for detecting flat lesion ≥4 mm increased to 84% (31/37). Conclusions: The fecal-tagging CTC with structure-analysis electronic cleansing could yield a high sensitivity for detecting flat lesions ≥4 mm. The not-on-fold flat lesions were detected with higher sensitivity than on-fold flat lesions.

Patient experience of CT colonography and colonoscopy after fecal occult blood test in a national screening programme

Energy Technology Data Exchange (ETDEWEB)

Plumb, Andrew A.; Taylor, Stuart A.; Halligan, Steve [University College London, Centre for Medical Imaging, Division of Medicine, London (United Kingdom); Ghanouni, Alex; Von Wagner, Christian [University College London, Health Behaviour Research Centre, Department of Epidemiology and Public Health, London (United Kingdom); Rees, Colin J. [Durham University School of Medicine, Pharmacy and Health, Durham (United Kingdom); Hewitson, Paul [University of Oxford, Health Services Research Unit, Nuffield Department of Population Health, Oxford (United Kingdom); Nickerson, Claire; Wright, Suzanne [Fulwood House, NHS Cancer Screening Programmes, Sheffield (United Kingdom)

2017-03-15

To investigate patient experience of CT colonography (CTC) and colonoscopy in a national screening programme. Retrospective analysis of patient experience postal questionnaires. We included screenees from a fecal occult blood test (FOBt) based screening programme, where CTC was performed when colonoscopy was incomplete or deemed unsuitable. We analyzed questionnaire responses concerning communication of test risks, test-related discomfort and post-test pain, as well as complications. CTC and colonoscopy responses were compared using multilevel logistic regression. Of 67,114 subjects identified, 52,805 (79 %) responded. Understanding of test risks was lower for CTC (1712/1970 = 86.9 %) than colonoscopy (48783/50975 = 95.7 %, p < 0.0001). Overall, a slightly greater proportion of screenees found CTC unexpectedly uncomfortable (506/1970 = 25.7 %) than colonoscopy (10,705/50,975 = 21.0 %, p < 0.0001). CTC was tolerated well as a completion procedure for failed colonoscopy (unexpected discomfort; CTC = 26.3 %: colonoscopy = 57.0 %, p < 0.001). Post-procedural pain was equally common (CTC: 288/1970,14.6 %, colonoscopy: 7544/50,975,14.8 %; p = 0.55). Adverse event rates were similar in both groups (CTC: 20/2947 = 1.2 %; colonoscopy: 683/64,312 = 1.1 %), but generally less serious with CTC. Even though CTC was reserved for individuals either unsuitable for or unable to complete colonoscopy, we found only small differences in test-related discomfort. CTC was well tolerated as a completion procedure and was extremely safe. CTC can be delivered across a national screening programme with high patient satisfaction. (orig.)

Reader error during CT colonography: causes and implications for training

International Nuclear Information System (INIS)

Slater, Andrew; Tam, Emily; Gartner, Louise; Scarth, Julia; Peiris, Chand; Gupta, Arun; Marshall, Michele; Burling, David; Taylor, Stuart A.; Halligan, Steve

2006-01-01

This study investigated the variability in baseline computed tomography colonography (CTC) performance using untrained readers by documenting sources of error to guide future training requirements. Twenty CTC endoscopically validated data sets containing 32 polyps were consensus read by three unblinded radiologists experienced in CTC, creating a reference standard. Six readers without prior CTC training [four residents and two board-certified subspecialty gastrointestinal (GI) radiologists] read the 20 cases. Readers drew a region of interest (ROI) around every area they considered a potential colonic lesion, even if subsequently dismissed, before creating a final report. Using this final report, reader ROIs were classified as true positive detections, true negatives correctly dismissed, true detections incorrectly dismissed (i.e., classification error), or perceptual errors. Detection of polyps 1-5 mm, 6-9 mm, and ≥10 mm ranged from 7.1% to 28.6%, 16.7% to 41.7%, and 16.7% to 83.3%, respectively. There was no significant difference between polyp detection or false positives for the GI radiologists compared with residents (p=0.67, p=0.4 respectively). Most missed polyps were due to failure of detection rather than characterization (range 82-95%). Untrained reader performance is variable but generally poor. Most missed polyps are due perceptual error rather than characterization, suggesting basic training should focus heavily on lesion detection. (orig.)

Implementation of a new CT colonography service: 5 Year experience

International Nuclear Information System (INIS)

Lung, P.F.C.; Burling, D.; Kallarackel, L.; Muckian, J.; Ilangovan, R.; Gupta, A.; Marshall, M.; Shorvon, P.; Halligan, S.; Bhatnagar, G.; Bassett, P.; Taylor, S.A.

2014-01-01

Aim: To describe our experience using a 5 year audit of computed tomography colonography (CTC) practice and identify factors that influence diagnostic performance to guide implementation in other centres. Material and methods: Consecutive patients referred for CTC at a single institution over a 5 year period were identified, and reporting rates and positive predictive value (PPV) calculated for small polyps, large polyps, and colorectal cancer. Diagnostic performance was compared using the Chi-squared test, and trends over time were examined with logistic regression. The effect of faecal tagging and an intravenous spasmolytic were investigated using Fisher's exact test. Results: In total, 4355 CTC examinations were performed. Overall reporting rates and PPV were 17% and 92%, respectively. Negative predictive value (NPV) for cancer was 99.9%. A significant decrease in reporting rate (p < 0.001) was accompanied by an increase in PPV for small polyps (p = 0.02) following the introduction of faecal tagging. Adequacy rates for CTC improved over time (96% to 99%), with improved adequacy rates when using a spasmolytic, 98% versus 96% without. A significant difference in reporting rates, but not PPV, was found between radiologists. Conclusion: Accurate colonic investigation using CTC can be delivered safely to a high-risk patient population at a single centre. Faecal tagging and an intravenous spasmolytic improve diagnostic performance

Assessment of the efficacy of the education of radiographers who interpret CT-colonography examinations

DEFF Research Database (Denmark)

Lauridsen, Carsten Ammitzbøl; Jeppesen, Lau; Westphal, Lena

2014-01-01

could increase the interpretation time and create significant logistical challenges in busy diagnostic imaging departments. The shortage of radiologists makes this an impractical long‐term solution; therefore diagnostic imaging departments should ensure efficient work routines and assess...... diagnostic modalities are used for colonic evaluation including rectoscopy, flexible sigmoideoscopy, OC, fecal occult blood test, double contrast barium enema, magnetic resonance colonography and CTC. However, OC is considered to be the gold standard due to a high diagnostic accuracy and the option......‐center trial reported excellent sensitivity for large adenomas and cancers.17 A further study by Kim et al., compared the diagnostic yield from parallel OC and CTC screening programs and found similar detection rates of advanced neoplasia in the two groups.18 Some studies have documented wide inter...

Effect of different reconstruction algorithms on computer-aided diagnosis (CAD) performance in ultra-low dose CT colonography

International Nuclear Information System (INIS)

Lee, Eun Sun; Kim, Se Hyung; Im, Jong Pil; Kim, Sang Gyun; Shin, Cheong-il; Han, Joon Koo; Choi, Byung Ihn

2015-01-01

Highlights: •We assessed the effect of reconstruction algorithms on CAD in ultra-low dose CTC. •30 patients underwent ultra-low dose CTC using 120 and 100 kVp with 10 mAs. •CT was reconstructed with FBP, ASiR and Veo and then, we applied a CAD system. •Per-polyp sensitivity of CAD in ULD CT can be improved with the IR algorithms. •Despite of an increase in the number of FPs with IR, it was still acceptable. -- Abstract: Purpose: To assess the effect of different reconstruction algorithms on computer-aided diagnosis (CAD) performance in ultra-low-dose CT colonography (ULD CTC). Materials and methods: IRB approval and informed consents were obtained. Thirty prospectively enrolled patients underwent non-contrast CTC at 120 kVp/10 mAs in supine and 100 kVp/10 mAs in prone positions, followed by same-day colonoscopy. Images were reconstructed with filtered back projection (FBP), 80% adaptive statistical iterative reconstruction (ASIR80), and model-based iterative reconstruction (MBIR). A commercial CAD system was applied and per-polyp sensitivities and numbers of false-positives (FPs) were compared among algorithms. Results: Mean effective radiation dose of CTC was 1.02 mSv. Of 101 polyps detected and removed by colonoscopy, 61 polyps were detected on supine and on prone CTC datasets on consensus unblinded review, resulting in 122 visible polyps (32 polyps <6 mm, 52 6–9.9 mm, and 38 ≥ 10 mm). Per-polyp sensitivity of CAD for all polyps was highest with MBIR (56/122, 45.9%), followed by ASIR80 (54/122, 44.3%) and FBP (43/122, 35.2%), with significant differences between FBP and IR algorithms (P < 0.017). Per-polyp sensitivity for polyps ≥ 10 mm was also higher with MBIR (25/38, 65.8%) and ASIR80 (24/38, 63.2%) than with FBP (20/38, 58.8%), albeit without statistical significance (P > 0.017). Mean number of FPs was significantly different among algorithms (FBP, 1.4; ASIR, 2.1; MBIR, 2.4) (P = 0.011). Conclusion: Although the performance of stand-alone CAD

Effect of different reconstruction algorithms on computer-aided diagnosis (CAD) performance in ultra-low dose CT colonography

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Sun [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of); Kim, Se Hyung, E-mail: shkim7071@gmail.com [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of); Im, Jong Pil; Kim, Sang Gyun [Department of Internal Medicine, Seoul National University Hospital (Korea, Republic of); Shin, Cheong-il; Han, Joon Koo; Choi, Byung Ihn [Department of Radiology, Seoul National University Hospital (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Hospital (Korea, Republic of)

2015-04-15

Highlights: •We assessed the effect of reconstruction algorithms on CAD in ultra-low dose CTC. •30 patients underwent ultra-low dose CTC using 120 and 100 kVp with 10 mAs. •CT was reconstructed with FBP, ASiR and Veo and then, we applied a CAD system. •Per-polyp sensitivity of CAD in ULD CT can be improved with the IR algorithms. •Despite of an increase in the number of FPs with IR, it was still acceptable. -- Abstract: Purpose: To assess the effect of different reconstruction algorithms on computer-aided diagnosis (CAD) performance in ultra-low-dose CT colonography (ULD CTC). Materials and methods: IRB approval and informed consents were obtained. Thirty prospectively enrolled patients underwent non-contrast CTC at 120 kVp/10 mAs in supine and 100 kVp/10 mAs in prone positions, followed by same-day colonoscopy. Images were reconstructed with filtered back projection (FBP), 80% adaptive statistical iterative reconstruction (ASIR80), and model-based iterative reconstruction (MBIR). A commercial CAD system was applied and per-polyp sensitivities and numbers of false-positives (FPs) were compared among algorithms. Results: Mean effective radiation dose of CTC was 1.02 mSv. Of 101 polyps detected and removed by colonoscopy, 61 polyps were detected on supine and on prone CTC datasets on consensus unblinded review, resulting in 122 visible polyps (32 polyps <6 mm, 52 6–9.9 mm, and 38 ≥ 10 mm). Per-polyp sensitivity of CAD for all polyps was highest with MBIR (56/122, 45.9%), followed by ASIR80 (54/122, 44.3%) and FBP (43/122, 35.2%), with significant differences between FBP and IR algorithms (P < 0.017). Per-polyp sensitivity for polyps ≥ 10 mm was also higher with MBIR (25/38, 65.8%) and ASIR80 (24/38, 63.2%) than with FBP (20/38, 58.8%), albeit without statistical significance (P > 0.017). Mean number of FPs was significantly different among algorithms (FBP, 1.4; ASIR, 2.1; MBIR, 2.4) (P = 0.011). Conclusion: Although the performance of stand-alone CAD

Computed tomographic colonography to screen for colorectal cancer, extracolonic cancer, and aortic aneurysm: model simulation with cost-effectiveness analysis.

Science.gov (United States)

Hassan, Cesare; Pickhardt, Perry J; Pickhardt, Perry; Laghi, Andrea; Kim, Daniel H; Kim, Daniel; Zullo, Angelo; Iafrate, Franco; Di Giulio, Lorenzo; Morini, Sergio

2008-04-14

In addition to detecting colorectal neoplasia, abdominal computed tomography (CT) with colonography technique (CTC) can also detect unsuspected extracolonic cancers and abdominal aortic aneurysms (AAA).The efficacy and cost-effectiveness of this combined abdominal CT screening strategy are unknown. A computerized Markov model was constructed to simulate the occurrence of colorectal neoplasia, extracolonic malignant neoplasm, and AAA in a hypothetical cohort of 100,000 subjects from the United States who were 50 years of age. Simulated screening with CTC, using a 6-mm polyp size threshold for reporting, was compared with a competing model of optical colonoscopy (OC), both without and with abdominal ultrasonography for AAA detection (OC-US strategy). In the simulated population, CTC was the dominant screening strategy, gaining an additional 1458 and 462 life-years compared with the OC and OC-US strategies and being less costly, with a savings of $266 and $449 per person, respectively. The additional gains for CTC were largely due to a decrease in AAA-related deaths, whereas the modeled benefit from extracolonic cancer downstaging was a relatively minor factor. At sensitivity analysis, OC-US became more cost-effective only when the CTC sensitivity for large polyps dropped to 61% or when broad variations of costs were simulated, such as an increase in CTC cost from $814 to $1300 or a decrease in OC cost from $1100 to $500. With the OC-US approach, suboptimal compliance had a strong negative influence on efficacy and cost-effectiveness. The estimated mortality from CT-induced cancer was less than estimated colonoscopy-related mortality (8 vs 22 deaths), both of which were minor compared with the positive benefit from screening. When detection of extracolonic findings such as AAA and extracolonic cancer are considered in addition to colorectal neoplasia in our model simulation, CT colonography is a dominant screening strategy (ie, more clinically effective and more cost

Exploration of analysis methods for diagnostic imaging tests: problems with ROC AUC and confidence scores in CT colonography.

Science.gov (United States)

Mallett, Susan; Halligan, Steve; Collins, Gary S; Altman, Doug G

2014-01-01

Different methods of evaluating diagnostic performance when comparing diagnostic tests may lead to different results. We compared two such approaches, sensitivity and specificity with area under the Receiver Operating Characteristic Curve (ROC AUC) for the evaluation of CT colonography for the detection of polyps, either with or without computer assisted detection. In a multireader multicase study of 10 readers and 107 cases we compared sensitivity and specificity, using radiological reporting of the presence or absence of polyps, to ROC AUC calculated from confidence scores concerning the presence of polyps. Both methods were assessed against a reference standard. Here we focus on five readers, selected to illustrate issues in design and analysis. We compared diagnostic measures within readers, showing that differences in results are due to statistical methods. Reader performance varied widely depending on whether sensitivity and specificity or ROC AUC was used. There were problems using confidence scores; in assigning scores to all cases; in use of zero scores when no polyps were identified; the bimodal non-normal distribution of scores; fitting ROC curves due to extrapolation beyond the study data; and the undue influence of a few false positive results. Variation due to use of different ROC methods exceeded differences between test results for ROC AUC. The confidence scores recorded in our study violated many assumptions of ROC AUC methods, rendering these methods inappropriate. The problems we identified will apply to other detection studies using confidence scores. We found sensitivity and specificity were a more reliable and clinically appropriate method to compare diagnostic tests.

CT colonography: effect of computer-aided detection of colonic polyps as a second and concurrent reader for general radiologists with moderate experience in CT colonography

International Nuclear Information System (INIS)

Mang, Thomas; Ringel, Helmut; Weber, Michael; Bogoni, Luca; Anand, Vikram X.; Hermosillo, Gerardo; Raykar, Vikas; Salganicoff, Marcos; Wolf, Matthias; Chandra, Dass; Curtin, Andrew J.; Lev-Toaff, Anna S.; Noah, Ralph; Shaw, Robert; Summerton, Susan; Tappouni, Rafel F.R.; Obuchowski, Nancy A.

2014-01-01

To assess the effectiveness of computer-aided detection (CAD) as a second reader or concurrent reader in helping radiologists who are moderately experienced in computed tomographic colonography (CTC) to detect colorectal polyps. Seventy CTC datasets (34 patients: 66 polyps ≥6 mm; 36 patients: no abnormalities) were retrospectively reviewed by seven radiologists with moderate CTC experience. After primary unassisted evaluation, a CAD second read and, after a time interval of ≥4 weeks, a CAD concurrent read were performed. Areas under the receiver operating characteristic (ROC) curve (AUC), along with per-segment, per-polyp and per-patient sensitivities, and also reading times, were calculated for each reader with and without CAD. Of seven readers, 86 % and 71 % achieved a higher accuracy (segment-level AUC) when using CAD as second and concurrent reader respectively. Average segment-level AUCs with second and concurrent CAD (0.853 and 0.864) were significantly greater (p < 0.0001) than average AUC in the unaided evaluation (0.781). Per-segment, per-polyp, and per-patient sensitivities for polyps ≥6 mm were significantly higher in both CAD reading paradigms compared with unaided evaluation. Second-read CAD reduced readers' average segment and patient specificity by 0.007 and 0.036 (p = 0.005 and 0.011), respectively. CAD significantly improves the sensitivities of radiologists moderately experienced in CTC for polyp detection, both as second reader and concurrent reader. (orig.)

Diagnostic performance of radiographers as compared to radiologists in magnetic resonance colonography

International Nuclear Information System (INIS)

Zijta, F.M.; Florie, J.; Jensch, S.; Bipat, S.; Nievelstein, R.A.J.; Poulus, M.; Thomassen-de Graaf, M.A.; Montauban van Swijndregt, A.D.; Stoker, J.

2010-01-01

Purpose: To evaluate the diagnostic performance of radiographers compared to radiologists in the detection of colorectal lesions in MR colonography. Material and methods: 159 patients at increased risk of colorectal cancer were included. Four different experienced observers, one MR radiologist, one radiologist in training and two radiographers evaluated all MR colonography examinations. The protocol included T1-weighted and T2-weighted sequences in prone and supine position. Colonoscopy was used as reference standard. Mean sensitivity rates with 95% confidence intervals (CIs) were determined on a per-patient and per-polyp basis, segmented by size (≥6 mm and ≥10 mm). Specificity was calculated on a per-patient basis. The McNemar and chi-square (χ 2 ) test was used to determine significant differences. Results: At colonoscopy 74 patients (47%) had normal findings; 23 patients had 40 polyps with a size ≥6 mm. In 10 patients at least 1 polyp ≥10 mm was found (20 polyps in total). Similar sensitivities for patients with lesions ≥10 mm were found for radiologists and radiographers (65% (95%CI: 44-86%) vs. 50% (95%CI: 28-72%)) (p = n.s.). For lesions ≥10 mm combined per-patient specificity for radiologists and radiographers was 96% (95%CI: 94-98%) and 73% (95%CI: 68-79%) (p < 0.0001). Combined per-patient sensitivity for lesions ≥6 mm differed significantly between both groups of observers (57% (95%CI: 42-71%) vs. 33% (95%CI: 19-46%)) (p = 0.03). Conclusion: Radiographers have comparable sensitivity but lower specificity relative to radiologists in the detection of colorectal lesions ≥10 mm at MR colonography. Adequate training in evaluating MR colonography is necessary, especially for readers with no prior experience with colonography.

Magnetic resonance colonography with a limited bowel preparation and automated carbon dioxide insufflation in comparison to conventional colonoscopy: Patient burden and preferences

Energy Technology Data Exchange (ETDEWEB)

Paardt, M.P. van der, E-mail: m.p.vanderpaardt@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Boellaard, T.N., E-mail: t.n.boellaard@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Zijta, F.M., E-mail: fmzijta@yahoo.com [Department of Radiology, Medisch Centrum Haaglanden, Den Haag (Netherlands); Baak, L.C., E-mail: l.c.baak@olvg.nl [Department of Gastroenterology and Hepatology, Onze Lieve Vrouwe Gasthuis, Amsterdam (Netherlands); Depla, A.C.T.M., E-mail: actm.depla@slz.nl [Department of Gastroenterology and Hepatology, Slotervaartziekenhuis, Amsterdam (Netherlands); Dekker, E., E-mail: e.dekker@amc.uva.nl [Department of Gastroenterology and Hepatology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Nederveen, A.J., E-mail: a.j.nederveen@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Bipat, S., E-mail: s.bipat@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Stoker, J., E-mail: j.stoker@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands)

2015-01-15

Highlights: • MR colonography with a limited bowel preparation and automated carbon dioxide insufflation demonstrated less burden compared to colonoscopy. • When discarding the bowel preparation, the examinations were rated equally burdensome. • The majority of patients preferred MR colonography over colonoscopy for their future examination of the bowel. - Abstract: Objectives: To evaluate patient burden and preferences for MR colonography with a limited bowel preparation and automated carbon dioxide insufflation in comparison to conventional colonoscopy. Methods: Symptomatic patients were consecutively recruited to undergo MR colonography with automated carbon dioxide insufflation and a limited bowel preparation followed within four weeks by colonoscopy with a standard bowel cleansing preparation. Four questionnaires regarding burden (on a five-point scale) and preferences (on a seven-point scale) were addressed after MR colonography and colonoscopy and five weeks after colonoscopy. Results: Ninety-nine patients (47 men, 52 women; mean age 62.3, SD 8.7) were included. None of the patients experienced severe or extreme burden from the MR colonography bowel preparation compared to 31.5% of the patients for the colonoscopy bowel preparation. Colonoscopy was rated more burdensome (25.6% severe or extreme burden) compared to MR colonography (5.2% severe or extreme burden) (P < 0.0001). When discarding the bowel preparations, the examinations were rated equally burdensome (P = 0.35). The majority of patients (61.4%) preferred MR colonography compared to colonoscopy (29.5%) immediately after the examinations and five weeks later (57.0% versus 39.5%). Conclusion: MR colonography with a limited bowel preparation and automated carbon dioxide insufflation demonstrated less burden compared to colonoscopy. The majority of patients preferred MR colonography over colonoscopy.

Evaluation of dose exposure in 64-slice CT colonography

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Luz, O.; Trabold, T.; Kopp, A.F.; Claussen, C.D.; Heuschmid, M. [University Hospital Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany); Buchgeister, M.; Klabunde, M. [University of Tuebingen, Institute of Medical Physics, Tuebingen (Germany)

2007-10-15

The radiation exposure of four different 64-slice MDCT-colonography (CTC) protocols was evaluated using an Alderson-Rando phantom. Protocols using 30 mAs (collimation 20 x 1.2mm), 50 mAs (collimation 20 x 1.2 and 64 x 0.6mm) and 80 mAs (20 x 1.2 mm) representing screening low-dose, routine, narrow collimation and oncologic staging setups were measured with an Alderson-Rando phantom (Alderson Research Laboratories Inc.). Scans were performed on a 64-row MDCT (SOMATOM Sensation 64, Siemens) simulating the prone and supine positions with a constant voltage of 120 kV. Dose values (male/female) were 2.5/2.9, 3.8/4.2, 4.2/4.5 and 5.7/6.4 mSv for 30, 50 (20 x 1.2 and 64 x 0.6 mm) and 80 mAs, respectively. Measurements showed an elevated dose for females (11.5% mean; compared to males). Use of narrow collimation combined with 50 mAs resulted in a small increase of dose exposure of 10.5 (male) and 7.1% (female). Gonad doses ranged from 0.9 to 2.6 mSv (male) and from 1.5 to 3.5 mSv (female). In all protocols, the stomach wall, lower colon, urinary bladder and liver were slightly more highly exposed (all <2.3 mSv) than the other organs, and the breast dose was <0.3 mSv in every setup. Values of radiation exposure in 64- and 16-slice CTC differ only marginally when using the narrow collimation. In 64-slice CTC, the use of narrow (64 x 0.6 mm) collimation shows slightly elevated dose values compared to wider (20 x 1.2 mm) collimation. (orig.)

Evaluation of dose exposure in 64-slice CT colonography

International Nuclear Information System (INIS)

Luz, O.; Trabold, T.; Kopp, A.F.; Claussen, C.D.; Heuschmid, M.; Buchgeister, M.; Klabunde, M.

2007-01-01

The radiation exposure of four different 64-slice MDCT-colonography (CTC) protocols was evaluated using an Alderson-Rando phantom. Protocols using 30 mAs (collimation 20 x 1.2mm), 50 mAs (collimation 20 x 1.2 and 64 x 0.6mm) and 80 mAs (20 x 1.2 mm) representing screening low-dose, routine, narrow collimation and oncologic staging setups were measured with an Alderson-Rando phantom (Alderson Research Laboratories Inc.). Scans were performed on a 64-row MDCT (SOMATOM Sensation 64, Siemens) simulating the prone and supine positions with a constant voltage of 120 kV. Dose values (male/female) were 2.5/2.9, 3.8/4.2, 4.2/4.5 and 5.7/6.4 mSv for 30, 50 (20 x 1.2 and 64 x 0.6 mm) and 80 mAs, respectively. Measurements showed an elevated dose for females (11.5% mean; compared to males). Use of narrow collimation combined with 50 mAs resulted in a small increase of dose exposure of 10.5 (male) and 7.1% (female). Gonad doses ranged from 0.9 to 2.6 mSv (male) and from 1.5 to 3.5 mSv (female). In all protocols, the stomach wall, lower colon, urinary bladder and liver were slightly more highly exposed (all <2.3 mSv) than the other organs, and the breast dose was <0.3 mSv in every setup. Values of radiation exposure in 64- and 16-slice CTC differ only marginally when using the narrow collimation. In 64-slice CTC, the use of narrow (64 x 0.6 mm) collimation shows slightly elevated dose values compared to wider (20 x 1.2 mm) collimation. (orig.)

Patient acceptability of CT colonography compared with double contrast barium enema: results from a multicentre randomised controlled trial of symptomatic patients

International Nuclear Information System (INIS)

Wagner, Christian von; Smith, Samuel; Ghanouni, Alex; Power, Emily; Wardle, Jane; Halligan, Steve; Lilford, Richard J.; Morton, Dion; Dadswell, Edward; Atkin, Wendy

2011-01-01

To determine patient acceptability of barium enema (BE) or CT colonography (CTC). After ethical approval, 921 consenting patients with symptoms suggestive of colorectal cancer who had been randomly assigned and completed either BE (N = 606) or CTC (N = 315) received a questionnaire to assess experience of the clinical episode including bowel preparation, procedure and complications. Satisfaction, worry and physical discomfort were assessed using an adapted version of a validated acceptability scale. Non-parametric methods assessed differences between the randomised tests and the effect of patient characteristics. Patients undergoing BE were significantly less satisfied (median 61, interquartile range [IQR] 54-67 vs. median 64, IQR 56-69; p = 0.003) and experienced more physical discomfort (median 40, IQR 29-52 vs. median 35.5, IQR 25-47; p < 0.001) than those undergoing CTC. Post-test, BE patients were significantly more likely to experience 'abdominal pain/cramps' (68% vs. 57%; p = 0.007), 'soreness' (57% vs. 37%; p < 0.001), 'nausea/vomiting' (16% vs. 8%; p = 0.009), 'soiling' (31% vs. 23%; p = 0.034) and 'wind' (92% vs. 84%; p = 0.001) and in the case of 'wind' to also rate it as severe (27% vs. 15%; p < 0.001). CTC is associated with significant improvements in patient experience. These data support the case for CTC to replace BE. (orig.)

Patient acceptability of CT colonography compared with double contrast barium enema: results from a multicentre randomised controlled trial of symptomatic patients.

Science.gov (United States)

von Wagner, Christian; Smith, Samuel; Halligan, Steve; Ghanouni, Alex; Power, Emily; Lilford, Richard J; Morton, Dion; Dadswell, Edward; Atkin, Wendy; Wardle, Jane

2011-10-01

To determine patient acceptability of barium enema (BE) or CT colonography (CTC). After ethical approval, 921 consenting patients with symptoms suggestive of colorectal cancer who had been randomly assigned and completed either BE (N = 606) or CTC (N = 315) received a questionnaire to assess experience of the clinical episode including bowel preparation, procedure and complications. Satisfaction, worry and physical discomfort were assessed using an adapted version of a validated acceptability scale. Non-parametric methods assessed differences between the randomised tests and the effect of patient characteristics. Patients undergoing BE were significantly less satisfied (median 61, interquartile range [IQR] 54-67 vs. median 64, IQR 56-69; p = 0.003) and experienced more physical discomfort (median 40, IQR 29-52 vs. median 35.5, IQR 25-47; p < 0.001) than those undergoing CTC. Post-test, BE patients were significantly more likely to experience 'abdominal pain/cramps' (68% vs. 57%; p = 0.007), 'soreness' (57% vs. 37%; p < 0.001), 'nausea/vomiting' (16% vs. 8%; p = 0.009), 'soiling' (31% vs. 23%; p = 0.034) and 'wind' (92% vs. 84%; p = 0.001) and in the case of 'wind' to also rate it as severe (27% vs. 15%; p < 0.001). CTC is associated with significant improvements in patient experience. These data support the case for CTC to replace BE.

Strategy for improving the detailed examination rate for colorectal cancer screening. New approach for detailed colorectal cancer examination. Study for optimal pre-treatment for CT colonography

International Nuclear Information System (INIS)

Mitsushima, Toru; Fujiwara, Masanori; Nagata, Koichi

2012-01-01

In order to drastically improve the detailed examination rate for strategic colorectal cancer examination in Japan, it is necessary to introduce CT colonography (CTC) as a detailed examination method for colorectal cancer examination, in addition to colonoscopy (CS) which is the conventional detailed examination method. In our study, a cleansing enema/contrast solution (3% Nif-C) was prepared by adding 60 ml of a water-soluble iodine-based contrast agent (Gastrografin) and water to an oral cleansing enema agent (Niflec) in solid (powder) form to a final amount of 2000 ml. The solution was compared with a Niflec solution. In terms of patient's acceptability, more than half of the examined patients answered ''easier to drink than the Niflec solution'' or ''as easy to drink as the Niflec solution. '' Also, the Nif-C solution was comparable or superior to the Niflec solution in terms of cleansing enema effects. Regarding imaging effects essential for CTC, the CT level was found to be 200 HU or greater for any large intestine region upon CTC using the Nif-C solution. Thus, practically sufficient imaging effects were achieved. In conclusion, CTC with pretreatment involving a cleansing enema with oral administration of 3% Nif-C is superior to CS in terms of patient's acceptability. In addition, at least in view of the overseas reports on CTC, there is no particular problem in terms of diagnostic accuracy. Thus, CTC is expected to resolve various problems related to colorectal cancer examination in Japan. (author)

Comparison between CT Colonography and Double-Contrast Barium Enema for Colonic Evaluation in Patients with Renal Insufficiency

International Nuclear Information System (INIS)

Chung, Sun Young; Park, Seong Ho; Lee, Seung Soo; Lee, Ju Hee; Kim, Ah Young; Park, Su Ki; Han, Duck Jong; Ha, Hyun Kwon

2012-01-01

To compare the CT colonography (CTC) and double-contrast barium enema (DCBE) for colonic evaluation in patients with renal insufficiency. Two sequential groups of consecutive patients with renal insufficiency who had a similar risk for colorectal cancer, were examined by DCBE (n = 182; mean ± SD in age, 51 ± 6.4 years) and CTC (n = 176; 50 ± 6.7 years), respectively. CTC was performed after colon cleansing with 250-mL magnesium citrate (n = 87) or 4-L polyethylene glycol (n = 89) and fecal tagging. DCBE was performed after preparation with 250-mL magnesium citrate. Patients with colonic polyps/masses of ≥ 6 mm were subsequently recommended to undergo a colonoscopy. Diagnostic yield and positive predictive value (PPV) for colonic polyps/masses, examination quality, and examination-related serum electrolyte change were retrospectively compared between the two groups. Both the CTC and DCBE were positive for colonic polyps/masses in 28 (16%) of 176 and 11 (6%) of 182 patients, respectively (p = 0.004). Among patients with positive findings, 17 CTC and six DCBE patients subsequently underwent a colonoscopy and yielded a PPV of 88% (15 of 17 patients) and 50% (3 of 6 patients), respectively (p = 0.089). Thirteen patients with adenomatous lesions were detected in the CTC group (adenocarcinoma [n = 1], advanced adenoma [n = 6], and non-advanced adenoma [n = 6]), as compared with two patients (each with adenocarcinoma and advanced adenoma) in the DCBE group (p = 0.003). Six (3%) of 176 CTC and 16 (9%) of 182 DCBE examinations deemed to be inadequate (p 0.046). Electrolyte changes were similar in the two groups. In patients with renal insufficiency, CTC has a higher diagnostic yield and a marginally higher PPV for detecting colorectal neoplasia, despite a similar diagnostic yield for adenocarcinoma, and a lower rate of inadequate examinations as compared with DCBE.

Comparison between CT colonography and double-contrast barium enema for colonic evaluation in patients with renal insufficiency.

Science.gov (United States)

Chung, Sun-Young; Park, Seong Ho; Lee, Seung Soo; Lee, Ju Hee; Kim, Ah Young; Park, Su-Kil; Han, Duck Jong; Ha, Hyun Kwon

2012-01-01

To compare the CT colonography (CTC) and double-contrast barium enema (DCBE) for colonic evaluation in patients with renal insufficiency. Two sequential groups of consecutive patients with renal insufficiency who had a similar risk for colorectal cancer, were examined by DCBE (n = 182; mean ± SD in age, 51 ± 6.4 years) and CTC (n = 176; 50 ± 6.7 years), respectively. CTC was performed after colon cleansing with 250-mL magnesium citrate (n = 87) or 4-L polyethylene glycol (n = 89) and fecal tagging. DCBE was performed after preparation with 250-mL magnesium citrate. Patients with colonic polyps/masses of ≥ 6 mm were subsequently recommended to undergo a colonoscopy. Diagnostic yield and positive predictive value (PPV) for colonic polyps/masses, examination quality, and examination-related serum electrolyte change were retrospectively compared between the two groups. Both the CTC and DCBE were positive for colonic polyps/masses in 28 (16%) of 176 and 11 (6%) of 182 patients, respectively (p = 0.004). Among patients with positive findings, 17 CTC and six DCBE patients subsequently underwent a colonoscopy and yielded a PPV of 88% (15 of 17 patients) and 50% (3 of 6 patients), respectively (p = 0.089). Thirteen patients with adenomatous lesions were detected in the CTC group (adenocarcinoma [n = 1], advanced adenoma [n = 6], and non-advanced adenoma [n = 6]), as compared with two patients (each with adenocarcinoma and advanced adenoma) in the DCBE group (p = 0.003). Six (3%) of 176 CTC and 16 (9%) of 182 DCBE examinations deemed to be inadequate (p = 0.046). Electrolyte changes were similar in the two groups. In patients with renal insufficiency, CTC has a higher diagnostic yield and a marginally higher PPV for detecting colorectal neoplasia, despite a similar diagnostic yield for adenocarcinoma, and a lower rate of inadequate examinations as compared with DCBE.

CT colonography: a survey of general practitioners' knowledge and interest.

Science.gov (United States)

Flor, Nicola; Laghi, Andrea; Peri, Mauro; Cornalba, Gianpaolo; Sardanelli, Francesco

2016-01-01

To verify the knowledge and interest of general practitioners on computed tomography colonography (CTC). In 2014, a Web-based questionnaire was proposed to all general practitioners of [Milan, Italy]. The questionnaire consisted of ten questions concerning general practitioners' knowledge about CTC, including application of guidelines in clinical scenarios and diagnostic performance. Out of 1,053 general practitioners, 231 (22%), 155 men and 76 women (mean age 58 years), completed the survey. We found a significant difference between the age of responders and that of non-responders (p = 0.0033). Of the 231 responders, 84% were aware of the possibility of using CTC as a method for examining the colon-rectum. However, only 57% were aware about low X-ray exposure delivered by CTC and about the possibility of using a reduced cleansing protocol. Only 48% were aware that CTC accuracy in diagnosing 10-mm or larger polyps and colorectal cancers was similar to that of conventional colonoscopy, while 62% were informed about CTC advantages in comparison with double-contrast barium enema; 59% thought that CTC had a potential role as a screening test; 85-86% suggested CTC in the case of refused or incomplete conventional colonoscopy; 79% suggested immediate conventional colonoscopy in the case of at least one 10-mm polyp. About 54% usually prescribe one CTC every 4-6 months, while 36% never have, 3% one CTC per month, and 7% one every 2-3 months. Ninety-four per cent declared that they were willing to attend a course on CTC. General practitioners have limited knowledge concerning CTC. Radiological societies should fill this gap offering dedicated educational initiatives.

Evaluation of image quality and lesion perception by human readers on 3D CT colonography: comparison of standard and low radiation dose

International Nuclear Information System (INIS)

Fisichella, Valeria A.; Allansdotter Johnsson, Aase; Hellstroem, Mikael; Baath, Magnus; Jaederling, Fredrik; Bergsten, Tommy; Persson, Ulf; Mellingen, Kristin

2010-01-01

We compared the prevalence of noise-related artefacts and lesion perception on three-dimensional (3D) CT colonography (CTC) at standard and low radiation doses. Forty-eight patients underwent CTC (64 x 0.625 mm collimation; tube rotation time 0.5 s; automatic tube current modulation: standard dose 40-160 mA, low dose 10-50 mA). Low- and standard-dose acquisitions were performed in the supine position, one after the other. The presence of artefacts (cobblestone and snow artefacts, irregularly delineated folds) and the presence of polyps were evaluated by five radiologists on 3D images at standard dose, the original low dose and a modified low dose, i.e. after manipulation of opacity on 3D. The mean effective dose was 3.9 ± 1.3 mSv at standard dose and 1.03 ± 0.4 mSv at low dose. The number of images showing cobblestone artefacts and irregularly delineated folds at original and modified low doses was significantly higher than at standard dose (P < 0.0001). Most of the artefacts on modified low-dose images were mild. No significant difference in sensitivity between the dose levels was found for polyps ≥6 mm. Reduction of the effective dose to 1 mSv significantly affects image quality on 3D CTC, but the perception of ≥6 mm lesions is not significantly impaired. (orig.)

CT-colonography in population-based colorectal cancer screening

NARCIS (Netherlands)

de Haan, M.C.

2012-01-01

In een proefbevolkingsonderzoek naar dikkedarmkanker vergeleek Margriet de Haan coloscopie (onderzoek met een dunne flexibele slang met camera om de darm van binnenuit te bekijken) met CT-colografie (onderzoek waarbij de darmen worden onderzocht zonder slang) wat betreft opkomst, opbrengst,

Measurement of smaller colon polyp in CT colonography images using morphological image processing.

Science.gov (United States)

Manjunath, K N; Siddalingaswamy, P C; Prabhu, G K

2017-11-01

Automated measurement of the size and shape of colon polyps is one of the challenges in Computed tomography colonography (CTC). The objective of this retrospective study was to improve the sensitivity and specificity of smaller polyp measurement in CTC using image processing techniques. A domain knowledge-based method has been implemented with hybrid method of colon segmentation, morphological image processing operators for detecting the colonic structures, and the decision-making system for delineating the smaller polyp-based on a priori knowledge. The method was applied on 45 CTC dataset. The key finding was that the smaller polyps were accurately measured. In addition to 6-9 mm range, polyps of even processing. It takes [Formula: see text] min for measuring the smaller polyp in a dataset of 500 CTC images. With this method, [Formula: see text] and [Formula: see text] were achieved. The domain-based approach with morphological image processing has given good results. The smaller polyps were measured accurately which helps in making right clinical decisions. Qualitatively and quantitatively the results were acceptable when compared to the ground truth at [Formula: see text].

Usefulness of multi detector row computed tomography for detection of flat and depressed colorectal cancer

International Nuclear Information System (INIS)

Izumiya, Takashi; Hirata, Ichiro; Hamamoto, Norihiro; Matsuki, Mitsuru; Narabayashi, Isamu; Nishiguchi, Kanji; Okuda, Junji; Tanigawa, Nobuhiko; Katsu, Ken-ichi

2005-01-01

Recently, the clinical usefulness of colorectal cancer screening by CT colonography has been reported in Europe and the USA. However, in Japan, the diagnosis of flat or depressed colorectal cancer lesions has been emphasized, and the question of whether CT colonography facilitates visualization of these lesions remains to be answered. In the present study, we compared the visualization of flat and depressed colorectal cancer lesions by CT colonography with that of protruding lesions. We investigated 33 Dukes A colorectal cancer lesions that had been examined by 3D-CT, colonoscopy, and barium enema prior to surgery. In all patients, CT colonography was performed immediately after colonoscopy. Volume rendering was used for 3-D rearrangement, and imaging findings were examined with respect to morphology, tumor diameter, and tumor height. All (14/14) of the protruding-type lesions were visualized by CT colonography, whereas 78.9% (15/19) of the flat and depressed-type lesions were visualized. There was no significant difference in tumor diameter between protruding-type lesions and flat and depressed-type lesions. With respect to tumor height, 100% of the lesions measuring 2 mm or more in height were visualized, whereas only 42.9% of those measuring less than 2 mm in height were visualized; the difference was significant (P<0.001). These results suggest that the visualization capacity of CT colonography is associated with tumor height, but not with tumor diameter. Currently, lesions measuring 2 mm or more in height can be visualized reliably by CT colonography. (authors)

Patient acceptability of CT colonography compared with double contrast barium enema: results from a multicentre randomised controlled trial of symptomatic patients

Energy Technology Data Exchange (ETDEWEB)

Wagner, Christian von; Smith, Samuel; Ghanouni, Alex; Power, Emily; Wardle, Jane [University College London, Department of Epidemiology and Public Health, London (United Kingdom); Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College Hospital, Centre for Medical Imaging, London (United Kingdom); Lilford, Richard J. [Birmingham University, Department of Epidemiology, Birmingham (United Kingdom); Morton, Dion [Birmingham University, Department of Surgery, Birmingham (United Kingdom); Dadswell, Edward; Atkin, Wendy [Imperial College London, Department of Surgery and Cancer, London (United Kingdom)

2011-10-15

To determine patient acceptability of barium enema (BE) or CT colonography (CTC). After ethical approval, 921 consenting patients with symptoms suggestive of colorectal cancer who had been randomly assigned and completed either BE (N = 606) or CTC (N = 315) received a questionnaire to assess experience of the clinical episode including bowel preparation, procedure and complications. Satisfaction, worry and physical discomfort were assessed using an adapted version of a validated acceptability scale. Non-parametric methods assessed differences between the randomised tests and the effect of patient characteristics. Patients undergoing BE were significantly less satisfied (median 61, interquartile range [IQR] 54-67 vs. median 64, IQR 56-69; p = 0.003) and experienced more physical discomfort (median 40, IQR 29-52 vs. median 35.5, IQR 25-47; p < 0.001) than those undergoing CTC. Post-test, BE patients were significantly more likely to experience 'abdominal pain/cramps' (68% vs. 57%; p = 0.007), 'soreness' (57% vs. 37%; p < 0.001), 'nausea/vomiting' (16% vs. 8%; p = 0.009), 'soiling' (31% vs. 23%; p = 0.034) and 'wind' (92% vs. 84%; p = 0.001) and in the case of 'wind' to also rate it as severe (27% vs. 15%; p < 0.001). CTC is associated with significant improvements in patient experience. These data support the case for CTC to replace BE. (orig.)

Effect of reducing abdominal compression during prone CT colonography on ascending colonic rotation during supine-to-prone positional change

International Nuclear Information System (INIS)

Jang, Jong eon; Park, Seong Ho; Lee, Jong Seok; Kim, Hyun Jin; KIm, Ah Young; Ha, Hyun Kwon

2016-01-01

To determine the effect of reduced abdominal compression in prone position on ascending colonic movement during supine-to-prone positional change during CT colonography (CTC). Eighteen consecutive patients who had undergone prone CTC scanning with cushion blocks placed under the chest and hip/thigh to reduce abdominal compression and had confirmed sessile polyps ≥ 6 mm in the well-distended, straight, mid-ascending colon, were included. Radial location along the ascending colonic luminal circumference (°) was measured for 24 polyps and 54 colonic teniae on supine and prone CTC images. The supine-to-prone change ranging between -180° and +180° (- and + for internal and external colonic rotations, respectively), was determined. In addition, possible causes of any ascending colonic rotations were explored. Abdominal compression during prone CTC scanning completely disappeared with the use of cushion blocks in 17 of 18 patients. However, some degrees of ascending colonic rotation were still observed, with the radial location changes of -22° to 61° (median, 13.9°) for the polyps and similar degrees for teniae. Fifty-four percent and 56% of polyps and teniae, respectively, showed changes > 10°. The radial location change of the polyps was significantly associated with the degree of anterior shift of the small bowel and mesentery (r = 0.722, p < 0.001) and the degree of posterior displacement of the ascending colon (r = 0.566, p = 0.004) during supine-to-prone positional change. Ascending colonic rotation upon supine-to-prone positional change during CTC, mostly in the form of external rotation, is not eliminated by removing abdominal compression in prone position

CT Colonography: Role of a second reader CAD paradigm in the initial training of radiologists

International Nuclear Information System (INIS)

Neri, Emanuele; Faggioni, Lorenzo; Regge, Daniele; Vagli, Paola; Turini, Francesca; Cerri, Francesca; Picano, Eugenia; Giusti, Sabina; Bartolozzi, Carlo

2011-01-01

Purpose: To evaluate the influence of CAD for the evaluation of CT colonography (CTC) datasets by inexperienced readers during the attendance of a dedicated hands-on training course. Method and materials: Twenty-seven radiologists inexperienced in CTC (11 with no CTC training at all, 16 having previously reviewed no more than 10 CTC cases overall) attended a hands-on training course based on direct teaching on fifteen workstations (four Advantage Windows 4.4 with Colon VCAR software, GE; six CADCOLON, Im3D; five ColonScreen (Toshiba/Voxar) with ColonCAD TM API, Medicsight). During the course, readers were instructed to analyze 26 CTC cases including 38 colonic lesions obtained through low-dose MDCT acquisitions, consisting of 12 polyps sized less than 6 mm, 9 polyps sized between 6 and 10 mm, 12 polyps sized between 11 mm and 30 mm, and 5 colonic masses sized >3 cm. CTC images were reviewed by each reader both in 2D and 3D mode, respectively by direct evaluation of native axial images and MPR reconstructions, and virtual endoscopy or dissected views. Each reader had 15 min time for assessing each dataset without CAD, after which results were compared with those provided by CAD software. Global rater sensitivity for each lesion size before and after CAD usage was compared by means of two-tailed Student's t test, while sensitivity of each single reader before and after CAD usage was assessed with the McNemar test. Results: For lesions sized 30 mm, sensitivity before CAD-assisted reading was 0.3556 ± 0.3105 and did not change after CAD usage (p = 1). Sensitivity of each single rater did not significantly differ before and after CAD for any lesion size category (McNemar test, p > 0.05). Specificity was not significantly different before and after CAD for any lesion size (>96% for all size categories). Conclusion: CAD usage led to increased overall sensitivity of inexperienced readers for all polyps sizes, except for lesions >30 mm, but sensitivity of individual raters

Appearances of screen-detected versus symptomatic colorectal cancers at CT colonography

International Nuclear Information System (INIS)

Plumb, Andrew A.; Pathiraja, Fiona; Taylor, Stuart A.; Halligan, Steve; Nickerson, Claire; Wooldrage, Katherine; Atkin, Wendy S.; Burling, David

2016-01-01

The aim of this study was to compare the morphology, radiological stage, conspicuity, and computer-assisted detection (CAD) characteristics of colorectal cancers (CRC) detected by computed tomographic colonography (CTC) in screening and symptomatic populations. Two radiologists independently analyzed CTC images from 133 patients diagnosed with CRC in (a) two randomized trials of symptomatic patients (35 patients with 36 tumours) and (b) a screening program using fecal occult blood testing (FOBt; 98 patients with 100 tumours), measuring tumour length, volume, morphology, radiological stage, and subjective conspicuity. A commercial CAD package was applied to both datasets. We compared CTC characteristics between screening and symptomatic populations with multivariable regression. Screen-detected CRC were significantly smaller (mean 3.0 vs 4.3 cm, p < 0.001), of lower volume (median 9.1 vs 23.2 cm 3 , p < 0.001) and more frequently polypoid (34/100, 34 % vs. 5/36, 13.9 %, p = 0.02) than symptomatic CRC. They were of earlier stage than symptomatic tumours (OR = 0.17, 95 %CI 0.07-0.41, p < 0.001), and were judged as significantly less conspicuous (mean conspicuity 54.1/100 vs. 72.8/100, p < 0.001). CAD detection was significantly lower for screen-detected (77.4 %; 95 %CI 67.9-84.7 %) than symptomatic CRC (96.9 %; 95 %CI 83.8-99.4 %, p = 0.02). Screen-detected CRC are significantly smaller, more frequently polypoid, subjectively less conspicuous, and less likely to be identified by CAD than those in symptomatic patients. (orig.)

Appearances of screen-detected versus symptomatic colorectal cancers at CT colonography

Energy Technology Data Exchange (ETDEWEB)

Plumb, Andrew A.; Pathiraja, Fiona; Taylor, Stuart A.; Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); Nickerson, Claire [Fulwood House, Public Health England, Sheffield (United Kingdom); Wooldrage, Katherine; Atkin, Wendy S. [Imperial College London, Department of Surgery and Cancer, London (United Kingdom); Burling, David [St Mark' s Hospital, Intestinal Imaging Centre, Harrow (United Kingdom)

2016-12-15

The aim of this study was to compare the morphology, radiological stage, conspicuity, and computer-assisted detection (CAD) characteristics of colorectal cancers (CRC) detected by computed tomographic colonography (CTC) in screening and symptomatic populations. Two radiologists independently analyzed CTC images from 133 patients diagnosed with CRC in (a) two randomized trials of symptomatic patients (35 patients with 36 tumours) and (b) a screening program using fecal occult blood testing (FOBt; 98 patients with 100 tumours), measuring tumour length, volume, morphology, radiological stage, and subjective conspicuity. A commercial CAD package was applied to both datasets. We compared CTC characteristics between screening and symptomatic populations with multivariable regression. Screen-detected CRC were significantly smaller (mean 3.0 vs 4.3 cm, p < 0.001), of lower volume (median 9.1 vs 23.2 cm{sup 3}, p < 0.001) and more frequently polypoid (34/100, 34 % vs. 5/36, 13.9 %, p = 0.02) than symptomatic CRC. They were of earlier stage than symptomatic tumours (OR = 0.17, 95 %CI 0.07-0.41, p < 0.001), and were judged as significantly less conspicuous (mean conspicuity 54.1/100 vs. 72.8/100, p < 0.001). CAD detection was significantly lower for screen-detected (77.4 %; 95 %CI 67.9-84.7 %) than symptomatic CRC (96.9 %; 95 %CI 83.8-99.4 %, p = 0.02). Screen-detected CRC are significantly smaller, more frequently polypoid, subjectively less conspicuous, and less likely to be identified by CAD than those in symptomatic patients. (orig.)

Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: systematic review and meta-analysis

Energy Technology Data Exchange (ETDEWEB)

Plumb, Andrew A.; Pendse, Douglas A.; Taylor, Stuart A. [University College London, Centre for Medical Imaging, London (United Kingdom); Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College London, University College Hospital, Centre for Medical Imaging, Podium Level 2, London (United Kingdom); Mallett, Susan [University of Oxford, Department of Primary Care Health Sciences, Oxford (United Kingdom)

2014-05-15

CT colonography (CTC) is recommended after positive faecal occult blood testing (FOBt) when colonoscopy is incomplete or infeasible. We aimed to estimate the sensitivity and specificity of CTC for colorectal cancer and adenomatous polyps following positive FOBt via systematic review. The MEDLINE, EMBASE, AMED and Cochrane Library databases were searched for CTC studies reporting sensitivity and specificity for colorectal cancer and adenomatous polyps. Included subjects had tested FOBt-positive by guaiac or immunochemical methods. Per-patient detection rates were summarized via forest plots. Meta-analysis of sensitivity and specificity was conducted using a bivariate random effects model and the average operating point calculated. Of 538 articles considered, 5 met inclusion criteria, describing results from 622 patients. Research study quality was good. CTC had a high per-patient average sensitivity of 88.8 % (95 % CI 83.6 to 92.5 %) for ≥6 mm adenomas or colorectal cancer, with low between-study heterogeneity. Specificity was both more heterogeneous and lower, at an average of 75.4 % (95 % CI 58.6 to 86.8 %). Few studies have investigated CTC in FOBt-positive individuals. CTC is sensitive at a ≥6 mm threshold but specificity is lower and variable. Despite the limited data, these results suggest that CTC may adequately substitute for colonoscopy when the latter is undesirable. (orig.)

Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: systematic review and meta-analysis

International Nuclear Information System (INIS)

Plumb, Andrew A.; Pendse, Douglas A.; Taylor, Stuart A.; Halligan, Steve; Mallett, Susan

2014-01-01

CT colonography (CTC) is recommended after positive faecal occult blood testing (FOBt) when colonoscopy is incomplete or infeasible. We aimed to estimate the sensitivity and specificity of CTC for colorectal cancer and adenomatous polyps following positive FOBt via systematic review. The MEDLINE, EMBASE, AMED and Cochrane Library databases were searched for CTC studies reporting sensitivity and specificity for colorectal cancer and adenomatous polyps. Included subjects had tested FOBt-positive by guaiac or immunochemical methods. Per-patient detection rates were summarized via forest plots. Meta-analysis of sensitivity and specificity was conducted using a bivariate random effects model and the average operating point calculated. Of 538 articles considered, 5 met inclusion criteria, describing results from 622 patients. Research study quality was good. CTC had a high per-patient average sensitivity of 88.8 % (95 % CI 83.6 to 92.5 %) for ≥6 mm adenomas or colorectal cancer, with low between-study heterogeneity. Specificity was both more heterogeneous and lower, at an average of 75.4 % (95 % CI 58.6 to 86.8 %). Few studies have investigated CTC in FOBt-positive individuals. CTC is sensitive at a ≥6 mm threshold but specificity is lower and variable. Despite the limited data, these results suggest that CTC may adequately substitute for colonoscopy when the latter is undesirable. (orig.)

Non- or full-laxative CT colonography vs. endoscopic tests for colorectal cancer screening: A randomised survey comparing public perceptions and intentions to undergo testing

Energy Technology Data Exchange (ETDEWEB)

Ghanouni, Alex; Wardle, Jane; Von Wagner, Christian [University College London, Health Behaviour Research Centre, Department of Epidemiology and Public Health, London (United Kingdom); Halligan, Steve; Plumb, Andrew; Boone, Darren [University College London, Centre for Medical Imaging, London (United Kingdom)

2014-07-15

Compare public perceptions and intentions to undergo colorectal cancer screening tests following detailed information regarding CT colonography (CTC; after non-laxative preparation or full-laxative preparation), optical colonoscopy (OC) or flexible sigmoidoscopy (FS). A total of 3,100 invitees approaching screening age (45-54 years) were randomly allocated to receive detailed information on a single test and asked to return a questionnaire. Outcomes included perceptions of preparation and test tolerability, health benefits, sensitivity and specificity, and intention to undergo the test. Six hundred three invitees responded with valid questionnaire data. Non-laxative preparation was rated more positively than enema or full-laxative preparations [effect size (r) = 0.13 to 0.54; p < 0.0005 to 0.036]; both forms of CTC and FS were rated more positively than OC in terms of test experience (r = 0.26 to 0.28; all p-values < 0.0005). Perceptions of health benefits, sensitivity and specificity (p = 0.250 to 0.901), and intention to undergo the test (p = 0.213) did not differ between tests (n = 144-155 for each test). Despite non-laxative CTC being rated more favourably, this study did not find evidence that offering it would lead to substantially higher uptake than full-laxative CTC or other methods. However, this study was limited by a lower than anticipated response rate. (orig.)

Detection of colorectal masses in CT colonography: application of deep residual networks for differentiating masses from normal colon anatomy

Science.gov (United States)

Näppi, Janne J.; Hironaka, Toru; Yoshida, Hiroyuki

2018-02-01

Even though the clinical consequences of a missed colorectal cancer far outweigh those of a missed polyp, there has been little work on computer-aided detection (CADe) for colorectal masses in CT colonography (CTC). One of the problems is that it is not clear how to manually design mathematical image-based features that could be used to differentiate effectively between masses and certain types of normal colon anatomy such as ileocecal valves (ICVs). Deep learning has demonstrated ability to automatically determine effective discriminating features in many image-based problems. Recently, residual networks (ResNets) were developed to address the practical problems of constructing deep network architectures for optimizing the performance of deep learning. In this pilot study, we compared the classification performance of a conventional 2D-convolutional ResNet (2D-ResNet) with that of a volumetric 3D-convolutional ResNet (3D-ResNet) in differentiating masses from normal colon anatomy in CTC. For the development and evaluation of the ResNets, 695 volumetric images of biopsy-proven colorectal masses, ICVs, haustral folds, and rectal tubes were sampled from 196 clinical CTC cases and divided randomly into independent training, validation, and test datasets. The training set was expanded by use of volumetric data augmentation. Our preliminary results on the 140 test samples indicate that it is feasible to train a deep volumetric 3D-ResNet for performing effective image-based discriminations in CTC. The 3D-ResNet slightly outperformed the 2D-ResNet in the discrimination of masses and normal colon anatomy, but the statistical difference between their very high classification accuracies was not significant. The highest classification accuracy was obtained by combining the mass-likelihood estimates of the 2D- and 3D-ResNets, which enabled correct classification of all of the masses.

Feasibility of Using the Marginal Blood Vessels as Reference Landmarks for CT Colonography

Science.gov (United States)

Wei, Zhuoshi; Yao, Jianhua; Wang, Shijun; Liu, Jiamin; Dwyer, Andrew J.; Pickhardt, Perry J.; Nowinski, Wieslaw L.; Summers, Ronald M.

2015-01-01

OBJECTIVE The purpose of this study was to show the spatial relationship of the colonic marginal blood vessels and the teniae coli on CT colonography (CTC) and the use of the marginal blood vessels for supine-prone registration of polyps and for determination of proper connectivity of collapsed colonic segments. MATERIALS AND METHODS We manually labeled the marginal blood vessels on 15 CTC examinations. Colon segmentation, centerline extraction, teniae detection, and teniae identification were automatically performed. For assessment of their spatial relationships, the distances from the marginal blood vessels to the three teniae coli and to the colon were measured. Student t tests (paired, two-tailed) were performed to evaluate the differences among these distances. To evaluate the reliability of the marginal vessels as reference points for polyp correlation, we analyzed 20 polyps from 20 additional patients who underwent supine and prone CTC. The average difference of the circumferential polyp position on the supine and prone scans was computed. Student t tests (paired, two-tailed) were performed to evaluate the supine-prone differences of the distance. We performed a study on 10 CTC studies from 10 patients with collapsed colonic segments by manually tracing the marginal blood vessels near the collapsed regions to resolve the ambiguity of the colon path. RESULTS The average distances (± SD) from the marginal blood vessels to the tenia mesocolica, tenia omentalis, and tenia libera were 20.1 ± 3.1 mm (95% CI, 18.5–21.6 mm), 39.5 ± 4.8 mm (37.1–42.0 mm), and 36.9 ± 4.2 mm (34.8–39.1 mm), respectively. Pairwise comparison showed that these distances to the tenia libera and tenia omentalis were significantly different from the distance to the tenia mesocolica (p marginal blood vessels to the colon wall was 15.3 ± 2.0 mm (14.2–16.3 mm). For polyp localization, the average difference of the circumferential polyp position on the supine and prone scans was 9

Radiation risk from CT: implications for cancer screening.

Science.gov (United States)

Albert, Jeffrey M

2013-07-01

The cancer risks associated with patient exposure to radiation from medical imaging have become a major topic of debate. The higher doses necessary for technologies such as CT and the increasing utilization of these technologies further increase medical radiation exposure to the population. Furthermore, the use of CT for population-based cancer screening continues to be explored for common malignancies such as lung cancer and colorectal cancer. Given the known carcinogenic effects of ionizing radiation, this warrants evaluation of the balance between the benefit of early cancer detection and the risk of screening-induced malignancy. This report provides a brief review of the process of radiation carcino-genesis and the literature evaluating the risk of malignancy from CT, with a focus on the risks and benefits of CT for cancer screening. The available data suggest a small but real risk of radiation-induced malignancy from CT that could become significant at the population level with widespread use of CT-based screening. However, a growing body of literature suggests that the benefits of CT screening for lung cancer in high-risk patients and CT colonography for colorectal cancer may significantly outweigh the radiation risk. Future studies evaluating the benefits of CT screening should continue to consider potential radiation risks.

Simethicone to prevent colonic bubbles during CT colonography performed with polyethylene glycol lavage and iohexol tagging: a randomized clinical trial.

Science.gov (United States)

Hong, Gil-Sun; Park, Seong Ho; Kim, Bohyun; Lee, Ju Hee; Kim, Jin Cheon; Yu, Chang Sik; Baek, Seunghee; Lee, Jong Seok; Kim, Hyun Jin

2015-04-01

The purpose of this study was to determine whether the occurrence of numerous colonic bubbles during CT colonography (CTC) performed with polyethylene glycol cleansing and oral iohexol fecal/fluid tagging could be prevented by use of simethicone. Adults with suspected colonic neoplasia who had been randomly assigned to control and simethicone intervention groups underwent CTC after cleansing with 4 L of polyethylene glycol, tagging with 50 mL of 350 mg I/mL oral iohexol, and without (control) or with (intervention) oral administration of 200 mg of simethicone. Colonic segments in the control and intervention groups were evaluated for amount of colonic bubbles during CTC. A 6-point grading system was used in which 0 indicated no bubbles and 5 indicated that more than three fourths of the air-distended mucosa was covered with bubbles. The primary endpoint was a per-patient colonic bubble grade, derived as an average of the segmental grades. Eighty adults with suspected colonic neoplasia were randomly assigned to the control (40 patients) and simethicone intervention (40 patients) groups. A total of 659 colonic segments in the control group and 689 segments in the intervention group were evaluated for amount of colonic bubbles during CTC. The per-patient colonic bubble score was significantly lower in the simethicone intervention group than in the control group. The mean score was 0.0±0.1 (SD) versus 1.2±0.8 (pgrade 0, and 16 (2.3%) were grade 1. In contrast, in the control group, 226 (34.3%) segments were grade 0; 173 (26.3%), grade 1; 175 (26.6%), grade 2; 45 (6.8%), grade 3; 23 (3.5%), grade 4; and 17 (2.6%), grade 5. The colonic bubbles associated with fecal/fluid tagging with iohexol can be successfully prevented by adding simethicone to the colonic preparation.

Computer-aided polyp detection on CT colonography: Comparison of three systems in a high-risk human population

International Nuclear Information System (INIS)

Park, Hee Sun; Kim, Se Hyung; Kim, Jong Hyo; Lee, June-Goo; Kim, Sang Gyun; Lee, Jeong Min; Lee, Jae Young; Han, Joon Koo; Choi, Byung Ihn

2010-01-01

Purpose: To compare the detection performances of two commercial and one academic computer-aided diagnosis (CAD) systems for polyp detection on CT colonography (CTC) in a high-risk human population and to assess their detection characteristics. Materials and methods: This retrospective study had institutional review board approval, but informed consent was waived. Sixty-eight patients who were suspected of having colonic polyps and scheduled for colonoscopic polyp removal were included. After CTC was performed using a 64-row MDCT, two commercial (PEV, CAR) and one academic (Hessian matrix-based) CAD systems were applied to each CTC dataset. Colonoscopy using the segmental unblinded technique was performed as a standard of reference. Per-polyp and per-patient sensitivities were calculated and compared for each CAD system. The mean number of false-positives (FPs) and false-negatives (FNs) was computed and the causes of all FPs and FNs were analyzed. Results: A total of 151 polyps in 61 patients were detected (77 polyps <6 mm, 48 6-9.9 mm, 26 ≥ 10 mm). Per-polyp sensitivity for PEV, CAR, and Hessian matrix-based CAD were: 71.6%, 78.4%, and 83.8% for polyps ≥6 mm, and 88.5%, 96.2%, and 96.2% for polyps ≥10 mm. Per-patient sensitivity for polyps ≥6 mm was 80.4%, 89.1%, and 93.5%, and 87%, 95.7%, and 95.7% for polyps ≥10 mm, respectively. Per-polyp and per-patient sensitivities were not significantly different among the three CAD systems regardless of size threshold. Mean number of FPs was 6.9 for PEV, 7.3 for CAR, and 14 for Hessian matrix-based CAD. The most common cause of FPs were feces, followed by extracolonic findings, prominent folds and ileocecal valve, and rectal tube. The distribution of the causes of FPs was significantly different among the three systems. Conclusion: Sensitivity of the three CAD systems for polyp detection was comparable regardless of the polyp size threshold; however, the number of FPs was higher in the Hessian matrix-based CAD

Magnetic resonance (MR) colonography in the detection of colorectal lesions: a systematic review of prospective studies

International Nuclear Information System (INIS)

Zijta, Frank M.; Bipat, Shandra; Stoker, Jaap

2010-01-01

To determine the diagnostic accuracy of MR-colonography for the detection of colorectal lesions. A comprehensive literature search was performed for comparative MR-colonography studies, published between May 1997 and February 2009, using the MEDLINE, EMBASE and Cochrane databases. We included studies if MR-colonography findings were prospectively compared with conventional colonoscopy in (a)symptomatic patients. Two reviewers independently extracted study design characteristics and data for summarising sensitivity and specificity. Heterogeneity in findings between studies was tested using I 2 test statistics. Sensitivity and specificity estimates with 95% confidence intervals (CI) were calculated on per patient basis and summary sensitivity on per polyp basis, using bivariate and univariate statistical models. Thirty-seven studies were found to be potentially relevant and 13 fulfilled the inclusion criteria. The study population comprised 1,285 patients with a mean disease prevalence of 44% (range 22-63%). Sensitivity for the detection of CRC was 100%. Significant heterogeneity was found for overall per patient sensitivity and specificity. For polyps with a size of 10 mm or larger, per patient sensitivity and specificity estimates were 88% (95% CI 63-97%; I 2 = 37%) and 99% (95% CI 95-100%; I 2 = 60%). On a per polyp basis, polyps of 10 mm or larger were detected with a sensitivity of 84% (95% CI 66-94%; I 2 = 51%). The data were too heterogeneous for polyps smaller than 6 mm and 6-9 mm. MR-colonography can accurately detect colorectal polyps more than 10 mm in size. (orig.)

Study of the usefulness of large intestine screening inspections using multi-slice CT (MSCT)

International Nuclear Information System (INIS)

Yamasaki, Michihiro; Nonogaki, Hidehiko; Hara, Koji; Naruse, Yutaka; Hara, Hiroto; Suematsu, Seiji; Yanase, Tadahiko; Otou, Taiji

2005-01-01

CT-colonography (CT-C), a new diagnostic imaging technique for cancer of the large intestine-which is increasing rapidly owing to westernized eating habits-has advanced from the developmental stage to the stage of practical application, thanks to progress in MSCT and workstation development. Therefore, based on the results of CT-C application using 16 lines of MSCT to a screening test, we reviewed the usefulness of CT-C in our clinic. We supplemented defective depiction, and found that change of position was effective for virtual image exclusion. We consider that CT-C can support diagnosis if the target of screening tests is a polypoid lesion of more than 6 mm. In addition, it is expected that the number of examinations performed during office visits will increase because of the decreased invasiveness of the procedure, its lack of pain, and its ability to provide early lesion detection. (author)

CT colonography: accuracy of initial interpretation by radiographers in routine clinical practice

International Nuclear Information System (INIS)

Burling, D.; Wylie, P.; Gupta, A.; Illangovan, R.; Muckian, J.; Ahmad, R.; Marshall, M.; Taylor, S.A.

2010-01-01

Aim: To investigate performance of computed-assisted detection (CAD)-assisted radiographers interpreting computed tomography colonography (CTC) in routine practice. Materials and methods: Three hundred and three consecutive symptomatic patients underwent CTC. Examinations were double-read by trained radiographers using primary two-dimensional/three-dimensional (2D/3D) analysis supplemented by 'second reader' CAD. Radiographers recorded colonic neoplasia, interpretation times, and patient management strategy code (S0, inadequate; S1, normal; S2, 6-9 mm polyp; S3, ≥10 mm polyp; S4, cancer; S5, diverticular stricture) for each examination. Strategies were compared to the reference standard using kappa statistic, interpretation times using paired t-test, learning curves using logistic regression and Pearson's correlation coefficient. Results: Of 303 examinations, 69 (23%) were abnormal. CAD-assisted radiographers detected 17/17 (100%) cancers, 21/28 (72%) polyps ≥10 mm and 42/60 (70%) 6-9 mm polyps. The overall agreement between radiographers and the reference management strategy was good (kappa 0.72; CI: 0.65, 0.78) with agreement for S1 strategy in 189/211 (90%) exams; S2 in 19/27 (70%); S3 in 12/19 (63%); S4 in 17/17 (100%); S5 in 5/6 (83%). The mean interpretation time was 17 min (SD = 11) compared with 8 min (SD = 3.5) for radiologists. There was no learning curve for recording correct strategies (OR 0.88; p = 0.12) but a significant reduction in interpretation times, mean 14 and 31 min (last/first 50 exams; -0.46; p < 0.001). Conclusion: Routine CTC interpretation by radiographers is effective for initial triage of patients with cancer, but independent reporting is currently not recommended.

Extracolonic findings (ECF) on CT colonography (CTC) in patients presenting with colorectal symptoms.

Science.gov (United States)

Badiani, Sarit; Tomas-Hernandez, Silvia; Karandikar, Sharad; Roy-Choudhury, Shuvro

2013-10-01

Computed tomographic colonography (CTC) is now an established method for imaging the colon and rectum in the screening and symptomatic setting. Additional benefit of CTC is the ability to assess for extracolonic findings especially in patients presenting with colorectal symptoms. To determine prevalence of extracolonic findings (ECF) in symptomatic patients undergoing CTC and determine accuracy of CTC for exclusion of significant abdominal disease and extracolonic malignancy (ECM). A total of 1359 unenhanced prone and postcontrast supine CTC studies were performed between March 2002 and December 2007. ECF were retrospectively classified according to C-RADS criteria into E1 to E4 findings. For ECM, a gold standard of clinical and/or radiological follow-up supplemented with data from the regional cancer registry with a median follow-up of 42 months was created. Sensitivity and negative predictive values for ECM was calculated. Following exclusions, 1177 CTCs were analyzed. Of 1423 extracolonic findings reported, 328/1423 (23%) E3 and 100/1423 (7%) E4 (including six eventual FP studies) findings were identified. Thirty-two ECMs were confirmed following further investigations. Seven further small ECMs were detected during the entire follow-up, of which two were potentially visible in retrospect (false-negative studies). Additional tests were generated from 55/1177 (4.7%) studies. Sensitivity and negative predictive value for ECM was 94.1% (95% CI 78.9-98.9%) and 99.8% (95% CI 99.3-99.9%), respectively. One in 37 patients were found to have an ECM. Two potentially detectable cancers were missed. Only a small proportion of patients underwent additional work-up.

Magnetic resonance colonography with limited bowel preparation: a comparison of three strategies

NARCIS (Netherlands)

Florie, Jasper; van Gelder, Rogier E.; Haberkorn, Brigitte; Birnie, Erwin; Lavini, Cristina; Reitsma, Johannes B.; Stoker, Jaap

2007-01-01

PURPOSE: To prospectively compare three strategies of magnetic resonance colonography (MRC) with fecal tagging. MATERIALS AND METHODS: Three strategies were compared: (S1) gadolinium as oral tagging agent and a gadolinium-water mixture for rectal filling (bright lumen), (S2) oral barium and water

CT colonography versus colonoscopy in the follow-up of patients after diverticulitis - A prospective, comparative study

International Nuclear Information System (INIS)

Hjern, F.; Jonas, E.; Holmstroem, B.; Josephson, T.; Mellgren, A.; Johansson, C.

2007-01-01

Aim: To assess whether computed tomography colonography (CTC) is a viable alternative to colonoscopy or double contrast barium enema in the follow-up of patients after diverticulitis. Material and methods: Fifty patients underwent CTC followed immediately by colonoscopy. Results were blinded to the examiners. Findings of diverticular disease and patient acceptance were evaluated. Results: Bowel preparation and distension were good in the majority of CTC and colonoscopy examinations. Diverticular disease was found in 96% of patients at CTC and in 90% at colonoscopy. The rate of agreement between CTC and colonoscopy for diverticular findings in the sigmoid colon was good (κ = 0.64). No complications were seen. Patients found colonoscopy more uncomfortable (p < 0.03), more painful (p < 0.001), and more difficult (p < 0.01) than CTC. Of the patients favouring one examination, 74% preferred CTC. Conclusion: CTC appears to have a better diagnostic potential for imaging of diverticular disease-specific findings, when compared with colonoscopy. Also, CTC was less uncomfortable and was preferred by a majority of patients. CTC seems to be a reasonable alternative in follow-up of patients with symptomatic diverticular disease

CT colonography with rectal iodine tagging: Feasibility and comparison with oral tagging in a colorectal cancer screening population.

Science.gov (United States)

Neri, Emanuele; Mantarro, Annalisa; Faggioni, Lorenzo; Scalise, Paola; Bemi, Pietro; Pancrazi, Francesca; D'Ippolito, Giuseppe; Bartolozzi, Carlo

2015-09-01

To evaluate feasibility, diagnostic performance, patient acceptance, and overall examination time of CT colonography (CTC) performed through rectal administration of iodinated contrast material. Six-hundred asymptomatic subjects (male:female=270:330; mean 63 years) undergoing CTC for colorectal cancer screening on an individual basis were consecutively enrolled in the study. Out of them, 503 patients (group 1) underwent CTC with rectal tagging, of which 55 had a total of 77 colonic lesions. The remaining 97 patients (group 2) were randomly selected to receive CTC with oral tagging of which 15 had a total of 20 colonic lesions. CTC findings were compared with optical colonoscopy, and per-segment image quality was visually assessed using a semi-quantitative score (1=poor, 2=adequate, 3=excellent). In 70/600 patients (11.7%), CTC was performed twice with both types of tagging over a 5-year follow-up cancer screening program. In this subgroup, patient acceptance was rated via phone interview two weeks after CTC using a semi-quantitative scale (1=poor, 2=fair, 3=average, 4=good, 5=excellent). Mean per-polyp sensitivity, specificity, positive and negative predictive values of CTC with rectal vs oral tagging were 96.1% (CI95% 85.4÷99.3%) vs 89.4% (CI95% 65.4÷98.1%), 95.3% (CI95% 90.7÷97.8%) vs 95.8% (CI95% 87.6÷98.9%), 86.0% (CI95% 73.6÷93.3) vs 85.0% (CI95% 61.1÷96.0%), and 98.8% (CI95% 95.3÷99.8%) vs 97.2% (CI95% 89.4÷99.5%), respectively (p>0.05). Polyp detection rates were not statistically different between groups 1 and 2 (p>0.05). Overall examination time was significantly shorter with rectal than with oral tagging (18.3±3.5 vs 215.6±10.3 minutes, respectively; pRectal iodine tagging can be an effective alternative to oral tagging for CTC with the advantages of greater patient acceptance and lower overall examination time. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Initial experience with computed tomographic colonography applied for noncolorectal cancerous conditions

International Nuclear Information System (INIS)

Ichikawa, Tamaki; Kawada, Shuichi; Hirata, Satoru; Ikeda, Shu; Sato, Yuuki; Imai, Yutaka

2011-01-01

The aim of this study was to asses retrospectively the performance of computed tomography colonography (CTC) for noncolorectal cancerous conditions. A total of 44 patients with non-colorectal cancerous conditions underwent CTC. We researched the indications for CTC or present illness and evaluated the CTC imaging findings. We assessed whether diagnosis by CTC reduced conventional colonoscopic examinations. A total of 47 examinations were performed in 44 patients. The indications for CTC or a present illness were as follows: 15 patients with impossible or incomplete colonoscopy, 7 with diverticular disease, 6 with malignancy (noncolorectal cancer), 6 with Crohn's disease, 4 suspected to have a submucosal tumor on colonoscopy, 2 with ischemic colitis, and 4 with various other diseases. Colonic findings were diagnosed on CTC in 36 examinations, and extracolonic findings were identified in 35 of 44 patients. In all, 17 patients had undergone colonoscopy previously, 9 (52.9%) of whom did not require further colonoscopy by CTC. Five patients underwent colonoscopy after CTC. The indications for CTC were varied for patients with noncolorectal cancerous conditions. CTC examinations could be performed safely. Unlike colonoscopy or CT without preparation, CTC revealed colonic and extracolonic findings and may reduce the indication of colonoscopy in patients with noncolorectal cancerous conditions. (author)

Extracolonic findings (ECF) on CT colonography (CTC) in patients presenting with colorectal symptoms

Energy Technology Data Exchange (ETDEWEB)

Sarit Badiani, Sarit; Karandikar, Sharad [Dept. of General Surgery, Heart of England Foundation Trust, Birmingham (United Kingdom); Tomas-Hernandez, Silvia; Roy-Choudhury; Shuvro [Dept. of Radiology, Heart of England Foundation Trust, Birmingham (United Kingdom)], e-mail: shurvrorc@googlemail.com

2013-10-15

Background: Computed tomographic colonography (CTC) is now an established method for imaging the colon and rectum in the screening and symptomatic setting. Additional benefit of CTC is the ability to assess for extracolonic findings especially in patients presenting with colorectal symptoms. Purpose: To determine prevalence of extracolonic findings (ECF) in symptomatic patients undergoing CTC and determine accuracy of CTC for exclusion of significant abdominal disease and extracolonic malignancy (ECM). Material and Methods: A total of 1359 unenhanced prone and postcontrast supine CTC studies were performed between March 2002 and December 2007. ECF were retrospectively classified according to C-RADS criteria into E1 to E4 findings. For ECM, a gold standard of clinical and/or radiological follow-up supplemented with data from the regional cancer registry with a median follow-up of 42 months was created. Sensitivity and negative predictive values for ECM was calculated. Results: Following exclusions, 1177 CTCs were analyzed. Of 1423 extracolonic findings reported, 328/1423 (23%) E3 and 100/1423 (7%) E4 (including six eventual FP studies) findings were identified. Thirty-two ECMs were confirmed following further investigations. Seven further small ECMs were detected during the entire follow-up, of which two were potentially visible in retrospect (false-negative studies). Additional tests were generated from 55/1177 (4.7%) studies. Sensitivity and negative predictive value for ECM was 94.1% (95% CI 78.9 - 98.9%) and 99.8% (95% CI 99.3 - 99.9%), respectively. Conclusion: One in 37 patients were found to have an ECM. Two potentially detectable cancers were missed. Only a small proportion of patients underwent additional work-up.

Virtual colonoscopy

Science.gov (United States)

Colonoscopy - virtual; CT colonography; Computed tomographic colonography; Colography - virtual ... Differences between virtual and conventional colonoscopy include: VC can view the colon from many different angles. This is not as easy ...

MR colonography with fecal tagging: comparison between 2D turbo FLASH and 3D FLASH sequences

International Nuclear Information System (INIS)

Papanikolaou, Nickolas; Grammatikakis, John; Maris, Thomas; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Lauenstein, Thomas

2003-01-01

The objective of this study was to compare inversion recovery turbo 2D fast low-angle shot (FLASH) and 3D FLASH sequences for fecal-tagged MR colonography studies. Fifteen consecutive patients with indications for colonoscopy underwent MR colonography with fecal tagging. An inversion recovery turbo-FLASH sequence was applied and compared in terms of artifacts presence, efficiency for masking residual stool, and colonic wall conspicuity with a fat-saturated 3D FLASH sequence. Both sequences were acquired following administration of paramagnetic contrast agent. Contrast-to-noise ratio and relative contrast between colonic wall and lumen were calculated and compared for both sequences. Turbo 2D FLASH provided fewer artifacts, higher efficiency for masking the residual stool, and colonic wall conspicuity equivalent to 3D FLASH. An inversion time of 10 ms provided homogeneously low signal intensity of the colonic lumen. Contrast to noise between colonic wall and lumen was significantly higher in the 3D FLASH images, whereas differences in relative contrast were not statistically significant. An optimized inversion-recovery 2D turbo-FLASH sequence provides better fecal tagging results and should be added to the 3D FLASH sequence when designing dark-lumen MR colonography examination protocols. (orig.)

Cost-effectiveness of computed tomographic colonography screening for colorectal cancer in the medicare population

NARCIS (Netherlands)

A.B. Knudsen (Amy); I. Lansdorp-Vogelaar (Iris); C.M. Rutter (Carolyn); J.E. Savarino (James); M. van Ballegooijen (Marjolein); K.M. Kuntz (Karen); A. Zauber (Ann)

2010-01-01

textabstractBackground The Centers for Medicare and Medicaid Services (CMS) considered whether to reimburse computed tomographic colonography (CTC) for colorectal cancer screening of Medicare enrollees. To help inform its decision, we evaluated the reimbursement rate at which CTC screening could be

A dimension reduction strategy for improving the efficiency of computer-aided detection for CT colonography

Science.gov (United States)

Song, Bowen; Zhang, Guopeng; Wang, Huafeng; Zhu, Wei; Liang, Zhengrong

2013-02-01

Various types of features, e.g., geometric features, texture features, projection features etc., have been introduced for polyp detection and differentiation tasks via computer aided detection and diagnosis (CAD) for computed tomography colonography (CTC). Although these features together cover more information of the data, some of them are statistically highly-related to others, which made the feature set redundant and burdened the computation task of CAD. In this paper, we proposed a new dimension reduction method which combines hierarchical clustering and principal component analysis (PCA) for false positives (FPs) reduction task. First, we group all the features based on their similarity using hierarchical clustering, and then PCA is employed within each group. Different numbers of principal components are selected from each group to form the final feature set. Support vector machine is used to perform the classification. The results show that when three principal components were chosen from each group we can achieve an area under the curve of receiver operating characteristics of 0.905, which is as high as the original dataset. Meanwhile, the computation time is reduced by 70% and the feature set size is reduce by 77%. It can be concluded that the proposed method captures the most important information of the feature set and the classification accuracy is not affected after the dimension reduction. The result is promising and further investigation, such as automatically threshold setting, are worthwhile and are under progress.

CT colonography after colostomy - clinical application and technical feasibility

International Nuclear Information System (INIS)

Nedevska, A.

2013-01-01

Full text:Introduction: The aim of this study was to evaluate the clinical application and technical implementation of computed tomographic (CT ) colonoscopy in patients undergoing sigmoid or rectal resection and following sigmoid colostomy in the course of standard diagnostic postoperative follow-up and prior to the reconstructive colon surgery. Materials and Methods: The study included 48 patients who underwent anterior abdomen-perineal or rectal resection and subsequent sigmoid colostomy in case of sigma or rectum carcinoma. The pre-procedure bowel preparation included a full colon cleansing and barium-based fecal tagging. The balloon catheter (18 F) is placed in the colonic stoma. The balloon is insufflated with 15-30 ml saline or air. The balloon was gently pulled until opening of the stoma has been closed completely. In 15 patients, a second catheter was placed in the remaining rectum. Contrast scanning in supination was done for all patients. An additional scanning in left and right lateral position was necessary for 9 patients. Results: All studies were carried out without any major complications. All patients tolerated the intubation and insufflation of air into the intestinal lumen. Two patients (4%) have evaluated the examination as uncomfortable. In 6 patients (12.5 %) it was impossible to evaluate the intestinal segments because due to a collapse of the wall. Five of them were localized in the descending colon. In 5 patients there was a significant amount of residual intestinal contents. The fecal tagging and intravenous contrast enhancing allowed the assessment of these intestinal segments. The rectal residue was correctly assessed in all patients in terms of length, position and wall changes. Conclusion: CT colonoscopy is applicable after sigmostoma in patients with abdomen-perineal and anterior rectal resection. Further in-depth studies are needed to determine the clinical indications and reliability of the method

Sub-milliSievert (sub-mSv) CT colonography: a prospective comparison of image quality and polyp conspicuity at reduced-dose versus standard-dose imaging

Energy Technology Data Exchange (ETDEWEB)

Lubner, Meghan G.; Pooler, B.D.; Kitchin, Douglas R.; Kim, David H.; Munoz del Rio, Alejandro; Pickhardt, Perry J. [University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, Departments of Radiology, Madison, WI (United States); Tang, Jie [University of Wisconsin School of Medicine and Public Health, Medical Physics, Madison, WI (United States); Li, Ke; Chen, Guang-Hong [University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, Departments of Radiology, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Medical Physics, Madison, WI (United States)

2015-07-15

To prospectively compare reduced-dose (RD) CT colonography (CTC) with standard-dose (SD) imaging using several reconstruction algorithms. Following SD supine CTC, 40 patients (mean age, 57.3 years; 17 M/23 F; mean BMI, 27.2) underwent an additional RD supine examination (targeted dose reduction, 70-90 %). DLP, CTDI{sub vol}, effective dose, and SSDE were compared. Several reconstruction algorithms were applied to RD series. SD-FBP served as reference standard. Objective image noise, subjective image quality and polyp conspicuity were assessed. Mean CTDI{sub vol} and effective dose for RD series was 0.89 mGy (median 0.65) and 0.6 mSv (median 0.44), compared with 3.8 mGy (median 3.1) and 2.8 mSv (median 2.3) for SD series, respectively. Mean dose reduction was 78 %. Mean image noise was significantly reduced on RD-PICCS (24.3 ± 19HU) and RD-MBIR (19 ± 18HU) compared with RD-FBP (90 ± 33), RD-ASIR (72 ± 27) and SD-FBP (47 ± 14 HU). 2D image quality score was higher with RD-PICCS, RD-MBIR, and SD-FBP (2.7 ± 0.4/2.8 ± 0.4/2.9 ± 0.6) compared with RD-FBP (1.5 ± 0.4) and RD-ASIR (1.8 ± 0.44). A similar trend was seen with 3D image quality scores. Polyp conspicuity scores were similar between SD-FBP/RD-PICCS/RD-MBIR (3.5 ± 0.6/3.2 ± 0.8/3.3 ± 0.6). Sub-milliSievert CTC performed with iterative reconstruction techniques demonstrate decreased image quality compared to SD, but improved image quality compared to RD images reconstructed with FBP. (orig.)

Automated image-based colon cleansing for laxative-free CT colonography computer-aided polyp detection

International Nuclear Information System (INIS)

Linguraru, Marius George; Panjwani, Neil; Fletcher, Joel G.; Summer, Ronald M.

2011-01-01

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%.

Computed tomographic colonography (CTC) performance: one-year clinical follow-up

International Nuclear Information System (INIS)

Duff, S.E.; Murray, D.; Rate, A.J.; Richards, D.M.; Kumar, N.A. Mahesh

2006-01-01

Aim: Computed tomographic colonography (CTC) represents a valuable advance in imaging technology for patients with colonic symptoms who are unfit for or fail to complete investigation with conventional techniques of colonoscopy or barium enema. The aim of this study was to examine whether CTC was sufficient to exclude colorectal cancer in such a population. As our patients were unfit for or unable to complete conventional investigations, we used 1 year clinical follow-up to exclude colonic malignancy. Materials and Methods: CTC examination was performed using multi-slice CT in patients fitting pre-determined criteria. All patients who had completed 12 months of follow-up after CTC were included. Data were extracted from patient records and lack of presentation within the 12 months following a negative CTC was assumed to equate to lack of colorectal cancer at initial investigation. Results: One hundred and twelve patients underwent CTC with a median age of 78 years (range 39-95) and median follow-up of 18 months (range 12-26). CTC detected 7 colorectal cancers, with 3 false positives and 1 false negative, giving a sensitivity of 87.5% and specificity of 97.1% for the detection of colorectal cancer. Conclusions: CTC is a good imaging tool for the exclusion of colorectal cancer in a population unfit for or unable to complete colonoscopy or barium enema, with reasonable sensitivity and specificity for detection of colorectal cancer. However, the optimum investigative strategy for fitter symptomatic individuals is still debated and should be clarified by the results of ongoing randomised controlled trials

CT colonography with rectal iodine tagging: Feasibility and comparison with oral tagging in a colorectal cancer screening population

International Nuclear Information System (INIS)

Neri, Emanuele; Mantarro, Annalisa; Faggioni, Lorenzo; Scalise, Paola; Bemi, Pietro; Pancrazi, Francesca; D’Ippolito, Giuseppe; Bartolozzi, Carlo

2015-01-01

Highlights: • In the group receiving rectal tagging, mean per-polyp sensitivity, specificity were 96.1% and 95.3%; while in the group receiving oral tagging, mean per-polyp sensitivity, specificity were 89.4% and 95.8%. The difference between the two groups was not statistically significant (p = 0.549). • Rectal tagging can be an effective alternative to oral tagging. • Rectal tagging allowed greater patient acceptance and lower overall examination time. - Abstract: Purpose: To evaluate feasibility, diagnostic performance, patient acceptance, and overall examination time of CT colonography (CTC) performed through rectal administration of iodinated contrast material. Materials and methods: Six-hundred asymptomatic subjects (male:female = 270:330; mean 63 years) undergoing CTC for colorectal cancer screening on an individual basis were consecutively enrolled in the study. Out of them, 503 patients (group 1) underwent CTC with rectal tagging, of which 55 had a total of 77 colonic lesions. The remaining 97 patients (group 2) were randomly selected to receive CTC with oral tagging of which 15 had a total of 20 colonic lesions. CTC findings were compared with optical colonoscopy, and per-segment image quality was visually assessed using a semi-quantitative score (1 = poor, 2 = adequate, 3 = excellent). In 70/600 patients (11.7%), CTC was performed twice with both types of tagging over a 5-year follow-up cancer screening program. In this subgroup, patient acceptance was rated via phone interview two weeks after CTC using a semi-quantitative scale (1 = poor, 2 = fair, 3 = average, 4 = good, 5 = excellent). Results: Mean per-polyp sensitivity, specificity, positive and negative predictive values of CTC with rectal vs oral tagging were 96.1% (CI 95% 85.4 ÷ 99.3%) vs 89.4% (CI 95% 65.4 ÷ 98.1%), 95.3% (CI 95% 90.7 ÷ 97.8%) vs 95.8% (CI 95% 87.6 ÷ 98.9%), 86.0% (CI 95% 73.6 ÷ 93.3) vs 85.0% (CI 95% 61.1 ÷ 96.0%), and 98.8% (CI 95% 95.3 ÷ 99.8%) vs 97.2% (CI 95% 89

CT colonography with rectal iodine tagging: Feasibility and comparison with oral tagging in a colorectal cancer screening population

Energy Technology Data Exchange (ETDEWEB)

Neri, Emanuele, E-mail: emanuele.neri@med.unipi.it [Diagnostic and Interventional Radiology – Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa (Italy); Mantarro, Annalisa; Faggioni, Lorenzo; Scalise, Paola; Bemi, Pietro; Pancrazi, Francesca [Diagnostic and Interventional Radiology – Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa (Italy); D’Ippolito, Giuseppe [Federal University of São Paulo – Sena Madureira 1500 – Vila Mariana, UNIFESP, São Paulo, SP (Brazil); Bartolozzi, Carlo [Diagnostic and Interventional Radiology – Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa (Italy)

2015-09-15

Highlights: • In the group receiving rectal tagging, mean per-polyp sensitivity, specificity were 96.1% and 95.3%; while in the group receiving oral tagging, mean per-polyp sensitivity, specificity were 89.4% and 95.8%. The difference between the two groups was not statistically significant (p = 0.549). • Rectal tagging can be an effective alternative to oral tagging. • Rectal tagging allowed greater patient acceptance and lower overall examination time. - Abstract: Purpose: To evaluate feasibility, diagnostic performance, patient acceptance, and overall examination time of CT colonography (CTC) performed through rectal administration of iodinated contrast material. Materials and methods: Six-hundred asymptomatic subjects (male:female = 270:330; mean 63 years) undergoing CTC for colorectal cancer screening on an individual basis were consecutively enrolled in the study. Out of them, 503 patients (group 1) underwent CTC with rectal tagging, of which 55 had a total of 77 colonic lesions. The remaining 97 patients (group 2) were randomly selected to receive CTC with oral tagging of which 15 had a total of 20 colonic lesions. CTC findings were compared with optical colonoscopy, and per-segment image quality was visually assessed using a semi-quantitative score (1 = poor, 2 = adequate, 3 = excellent). In 70/600 patients (11.7%), CTC was performed twice with both types of tagging over a 5-year follow-up cancer screening program. In this subgroup, patient acceptance was rated via phone interview two weeks after CTC using a semi-quantitative scale (1 = poor, 2 = fair, 3 = average, 4 = good, 5 = excellent). Results: Mean per-polyp sensitivity, specificity, positive and negative predictive values of CTC with rectal vs oral tagging were 96.1% (CI{sub 95%} 85.4 ÷ 99.3%) vs 89.4% (CI{sub 95%} 65.4 ÷ 98.1%), 95.3% (CI{sub 95%} 90.7 ÷ 97.8%) vs 95.8% (CI{sub 95%} 87.6 ÷ 98.9%), 86.0% (CI{sub 95%} 73.6 ÷ 93.3) vs 85.0% (CI{sub 95%} 61.1 ÷ 96.0%), and 98.8% (CI{sub 95

CT colonography in a Korean population with a high residue diet: Comparison between wet and dry preparations

International Nuclear Information System (INIS)

Kim, S.H.; Choi, B.I.; Han, J.K.; Lee, J.M.; Eun, H.W.; Lee, J.Y.; Lee, K.H.; Han, C.J.; Choi, Y.H.; Shin, K.-S.

2006-01-01

AIM: To compare wet and dry preparation methods for computed tomography colonography (CTC) in terms of preparation quality, interpretation time, and diagnostic performance for polyp detection in a population with a high residue diet. MATERIALS AND METHODS: Eighty-six patients were divided into two groups. Group 1 (n=24) received a wet preparation of 4 l polyethylene glycol (PEG) solution, and group 2 (n=62) received a dry preparation of phosphor-soda. Abnormal findings, including polyps, and the time required to interpret the CTC images in both groups were documented by a radiologist. CTC findings were compared to those of colonoscopy as a reference standard. Two radiologists evaluated the quality of CTC with regard to residual fluid, faeces, and colonic distension using a four-point scale in consensus. Statistical differences for residual fluid, faeces, distensibility on CTC, and interpretation time between the two groups were analysed. The diagnostic performance of CTC in both groups was also compared. RESULTS: One-hundred and ninety polyps in 70 patients were identified using colonoscopy. Regarding the quality of images produced the wet preparation was significantly better than the dry preparation (p 0.05). CONCLUSION: In a population with a high-residue diet, CTC with wet preparation can be interpreted in a time-efficient manner and is comparable with CTC with dry preparation

Prevalence of incidental or unexpected findings on low-dose CT performed during routine SPECT/CT nuclear medicine studies

International Nuclear Information System (INIS)

Yap, Kelvin Kwok-Ho; Sutherland, Tom; Shafik-Eid, Raymond; Taubman, Kim; Schlicht, Stephen; Ramaseshan, Ganeshan

2015-01-01

In nuclear medicine, single-photon-emission computed tomography (SPECT) is often combined with ‘simultaneous’ low-dose CT (LDCT) to provide complementary anatomical and functional correlation. As a consequence, numerous incidental and unexpected findings may be detected on LDCT. Recognition of these findings and appropriate determination of their relevance can add to the utility of SPECT/CT. We aimed to evaluate the prevalence and categorise the relevance of incidental and unexpected findings on LDCT scans performed as part of routine SPECT/CT studies. All available LDCT scans performed as part of SPECT/CT studies at St. Vincent's Hospital Melbourne in the year 2013 were retrospectively reviewed. Two qualified radiologists independently reviewed the studies and any previous available imaging and categorised any detected incidental findings. A total of 2447 LDCT studies were reviewed. The relevance of the findings was classified according to a modified version of a scale used in the Colonography Reporting and Data System: E1 = normal or normal variant (28.0%); E2 = clinically unimportant (63.5%); E3 = likely unimportant or incompletely characterised (6.2%); E4 = potentially important (2.5%). Imaging specialists need to be cognisant of incidental and unexpected findings present on LDCT studies performed as part of SPECT/CT. Appropriate categorisation of findings and communication of potentially important findings to referring clinicians should form part of routine practice. The overall prevalence of potentially significant incidental and unexpected findings in our series was 8.7% (E3, 6.2%; E4, 2.5%) and was comparable to rates in other published imaging series.

Adverse events during CT colonography for screening, diagnosis and preoperative staging of colorectal cancer: a Japanese national survey

Energy Technology Data Exchange (ETDEWEB)

Nagata, Koichi [Japanese Society of Gastrointestinal Cancer Screening, Committee for Quality Assessment of Colorectal Cancer Screening, Tokyo (Japan); Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); National Cancer Centre, Division of Screening Technology, Centre for Public Health Sciences, Tokyo (Japan); Takabayashi, Ken [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); National Cancer Centre, Division of Screening Technology, Centre for Public Health Sciences, Tokyo (Japan); Hokkaido Gastroenterology Hospital, Department of Radiology, Sapporo (Japan); Yasuda, Takaaki [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); National Cancer Centre, Division of Screening Technology, Centre for Public Health Sciences, Tokyo (Japan); Nagasaki Kamigoto Hospital, Department of Radiology, Nagasaki (Japan); Hirayama, Michiaki [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); Tonan Hospital, Department of Gastroenterology, Sapporo (Japan); Endo, Shungo [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); Fukushima Medical University, Department of Coloproctology, Aizu Medical Centre, Aizu-Wakamatsu, Fukushima (Japan); Nozaki, Ryoichi [Japanese Society of Gastrointestinal Cancer Screening, Committee for Quality Assessment of Colorectal Cancer Screening, Tokyo (Japan); Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); Takano Hospital, Coloproctology Centre, Kumamoto (Japan); Shimada, Takenobu [Japanese Society of Gastrointestinal Cancer Screening, Committee for Quality Assessment of Colorectal Cancer Screening, Tokyo (Japan); Cancer Detection Centre of the Miyagi Cancer Society, Sendai, Miyagi (Japan); Kanazawa, Hidenori [National Cancer Centre, Division of Screening Technology, Centre for Public Health Sciences, Tokyo (Japan); Jichi Medical University, Department of Radiology, Shimotsuke, Tochigi (Japan); Fujiwara, Masanori [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); Kameda Medical Centre Makuhari, Radiology Section, Mihama-ku, Chiba (Japan); Shimizu, Norihito [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); Matsuoka Clinic, Radiology Section, Nara (Japan); Iwatsuki, Tatema [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); Matsuda Hospital, Radiology Section, Hamamatsu, Shizuoka (Japan); Iwano, Teruaki [Gastrointestinal Advanced Imaging Academy, Tochigi (Japan); Tokushima Kensei Hospital, Radiology Section, Tokushima (Japan); Saito, Hiroshi [Japanese Society of Gastrointestinal Cancer Screening, Committee for Quality Assessment of Colorectal Cancer Screening, Tokyo (Japan); National Cancer Centre, Division of Screening Assessment and Management, Centre for Public Health Sciences, Tokyo (Japan)

2017-12-15

To retrospectively evaluate the frequencies and magnitudes of adverse events associated with computed tomographic colonography (CTC) for screening, diagnosis and preoperative staging of colorectal cancer. A Japanese national survey on CTC was administered by use of an online survey tool in the form of a questionnaire. The questions covered mortality, colorectal perforation, vasovagal reaction, total number of examinations, and examination procedures. The survey data was collated and raw frequencies were determined. Fisher's exact test was used to determine differences in event rates between groups. At 431 institutions, 147,439 CTC examinations were performed. No deaths were reported. Colorectal perforations occurred in 0.014% (21/147,439): 0.003% (1/29,823) in screening, 0.014% (13/91,007) in diagnosis and 0.028% (7/25,330) in preoperative staging. The perforation risk was significantly lower in screening than in preoperative staging CTC procedures (p = 0.028). Eighty-one per cent of perforation cases (17/21) did not require emergency surgery. Vasovagal reaction occurred in 0.081% (120/147,439): 0.111% (33/29,823) in screening, 0.088% (80/91,007) in diagnosis and 0.028% (7/25,330) in preoperative staging. The risk of colorectal perforation and vasovagal reaction in CTC is low. The frequency of colorectal perforation associated with CTC is least in the screening group and greatest in the preoperative-staging group. (orig.)

Adverse events during CT colonography for screening, diagnosis and preoperative staging of colorectal cancer: a Japanese national survey

International Nuclear Information System (INIS)

Nagata, Koichi; Takabayashi, Ken; Yasuda, Takaaki; Hirayama, Michiaki; Endo, Shungo; Nozaki, Ryoichi; Shimada, Takenobu; Kanazawa, Hidenori; Fujiwara, Masanori; Shimizu, Norihito; Iwatsuki, Tatema; Iwano, Teruaki; Saito, Hiroshi

2017-01-01

To retrospectively evaluate the frequencies and magnitudes of adverse events associated with computed tomographic colonography (CTC) for screening, diagnosis and preoperative staging of colorectal cancer. A Japanese national survey on CTC was administered by use of an online survey tool in the form of a questionnaire. The questions covered mortality, colorectal perforation, vasovagal reaction, total number of examinations, and examination procedures. The survey data was collated and raw frequencies were determined. Fisher's exact test was used to determine differences in event rates between groups. At 431 institutions, 147,439 CTC examinations were performed. No deaths were reported. Colorectal perforations occurred in 0.014% (21/147,439): 0.003% (1/29,823) in screening, 0.014% (13/91,007) in diagnosis and 0.028% (7/25,330) in preoperative staging. The perforation risk was significantly lower in screening than in preoperative staging CTC procedures (p = 0.028). Eighty-one per cent of perforation cases (17/21) did not require emergency surgery. Vasovagal reaction occurred in 0.081% (120/147,439): 0.111% (33/29,823) in screening, 0.088% (80/91,007) in diagnosis and 0.028% (7/25,330) in preoperative staging. The risk of colorectal perforation and vasovagal reaction in CTC is low. The frequency of colorectal perforation associated with CTC is least in the screening group and greatest in the preoperative-staging group. (orig.)

Reducing the oral contrast dose in CT colonography: evaluation of faecal tagging quality and patient acceptance

International Nuclear Information System (INIS)

Liedenbaum, M.H.; Denters, M.J.; Zijta, F.M.; Ravesteijn, V.F. van; Bipat, S.; Vos, F.M.; Dekker, E.; Stoker, J.

2011-01-01

Aim: To evaluate the minimal iodine contrast medium load necessary for an optimal computed tomography colonography tagging quality. Materials and Methods: Faecal occult blood test positive patients were randomly selected for one of three iodine bowel preparations: (1) 3 x 50 ml meglumine ioxithalamate (45 g iodine), (2) 4 x 25 ml meglumine ioxithalamate (30 g iodine); or (3) 3 x 25 ml (22.5 g iodine) meglumine ioxithalamate. Two experienced readers assessed the tagging quality per colonic segment on a five-point scale and the presence of adherent stool. Also semi-automatic homogeneity measurements were performed. Patient acceptance was assessed with questionnaires. Results: Of 70 eligible patients, 45 patients participated (25 males, mean age 62 years). Each preparation group contained 15 patients. The quality of tagging was insufficient (score 1-2) in 0% of segments in group 1; 4% in group 2 (p < 0.01 versus group 1); and 5% in group 3 (p = 0.06 versus group 1). In group 1 in 11% of the segments adherent stool was present compared with 49% in group 2 and 41% in group 3 (p < 0.01, group 2 and 3 versus group 1). Homogeneity was 85, 102 (p < 0.01), and 91 SD HU (p = 0.26) in groups 1, 2, and 3, respectively. In group 1 two patients experienced no burden after contrast agent ingestion compared to one patient in group 2 and nine patients in group 3 (p = 0.017). Conclusion: A dose of 3 x 50 ml meglumine ioxithalamate is advisable for an optimal tagging quality despite beneficial effects on the patient acceptance in patients receiving a lower dose.

Parallel imaging enhanced MR colonography using a phantom model.

LENUS (Irish Health Repository)

Morrin, Martina M

2008-09-01

To compare various Array Spatial and Sensitivity Encoding Technique (ASSET)-enhanced T2W SSFSE (single shot fast spin echo) and T1-weighted (T1W) 3D SPGR (spoiled gradient recalled echo) sequences for polyp detection and image quality at MR colonography (MRC) in a phantom model. Limitations of MRC using standard 3D SPGR T1W imaging include the long breath-hold required to cover the entire colon within one acquisition and the relatively low spatial resolution due to the long acquisition time. Parallel imaging using ASSET-enhanced T2W SSFSE and 3D T1W SPGR imaging results in much shorter imaging times, which allows for increased spatial resolution.

Health economic aspects of evaluation with diffusion weighted MR and MR colonography compared to standard evaluation with colonoscopy and CT before rectal cancer surgery

DEFF Research Database (Denmark)

Achiam, Michael P; Kjellberg, Jakob; Rosenberg, Jacob

2017-01-01

calculation and a practical cost calculation. The cost drivers utilized are an average cost based on the cost of all procedures and diagnostic modalities performed in hospitalized patients (DRG) and outpatients (DAGS [Danish outpatient grouping system]) in Denmark. Results The total cost for a full colorectal......) colonography and diffusion-weighted MR of the liver. Purpose To compare the economic aspects of this modality with the standard evaluation in an analysis of the different cost drivers. Material and Methods Based on the results from previous studies, two calculations were performed, a theoretical cost...... the two preoperative diagnostic modalities per patient were €312 and €712, respectively. Conclusion This cost analysis shows the cost effectiveness of the new modality as the future standard preoperative diagnostic work-up by reducing total cost and by having a higher sensitivity and completion rate....

Patient acceptance of MR colonography with improved fecal tagging versus conventional colonoscopy

International Nuclear Information System (INIS)

Achiam, M.P.; Logager, V.; Chabanova, E.; Thomsen, H.S.; Rosenberg, J.

2010-01-01

Objective: Conventional colonoscopy (CC) is the gold standard for colonic examinations. However, patient acceptance is not high. Patient acceptance is influenced by several factors, notably anticipation and experience. This has led to the assumption that patient acceptance would be higher in non-invasive examinations such as MR/CT colonography (MRC/CTC) and perhaps even higher without bowel preparation. The purpose of this study was to evaluate patient acceptance of MRC with fecal tagging versus CC. Materials and methods: In a 14-month period, all patients first-time referred to our department for CC were asked to participate in the study. Two days prior to MRC, patients ingested an oral contrast mixture (barium/ferumoxsil) together with four meals each day. Standard bowel purgation was performed before CC. Before and after MRC and CC a number of questions were addressed. Results: Sixty-four (34 men, 30 women) patients referred for CC participated in the study. 27% had some discomfort ingesting the contrast mixture, and 49% had some discomfort with the bowel purgation. As a future colonic examination preference, 71% preferred MRC, 13% preferred CC and 15% had no preference. If MRC was to be performed with bowel purgation, 75% would prefer MRC, 12% would prefer CC and 12% had no preference. Conclusion: This study shows that there is a potential gain in patient acceptance by using MRC for colonic examination, since MRC is considered less painful and less unpleasant than CC. In addition, the results indicate that patients in this study prefer fecal tagging instead of bowel purgation.

Registration of prone and supine CT colonography scans using correlation optimized warping and canonical correlation analysis

International Nuclear Information System (INIS)

Wang Shijun; Yao Jianhua; Liu Jiamin; Petrick, Nicholas; Van Uitert, Robert L.; Periaswamy, Senthil; Summers, Ronald M.

2009-01-01

Purpose: In computed tomographic colonography (CTC), a patient will be scanned twice--Once supine and once prone--to improve the sensitivity for polyp detection. To assist radiologists in CTC reading, in this paper we propose an automated method for colon registration from supine and prone CTC scans. Methods: We propose a new colon centerline registration method for prone and supine CTC scans using correlation optimized warping (COW) and canonical correlation analysis (CCA) based on the anatomical structure of the colon. Four anatomical salient points on the colon are first automatically distinguished. Then correlation optimized warping is applied to the segments defined by the anatomical landmarks to improve the global registration based on local correlation of segments. The COW method was modified by embedding canonical correlation analysis to allow multiple features along the colon centerline to be used in our implementation. Results: We tested the COW algorithm on a CTC data set of 39 patients with 39 polyps (19 training and 20 test cases) to verify the effectiveness of the proposed COW registration method. Experimental results on the test set show that the COW method significantly reduces the average estimation error in a polyp location between supine and prone scans by 67.6%, from 46.27±52.97 to 14.98 mm±11.41 mm, compared to the normalized distance along the colon centerline algorithm (p<0.01). Conclusions: The proposed COW algorithm is more accurate for the colon centerline registration compared to the normalized distance along the colon centerline method and the dynamic time warping method. Comparison results showed that the feature combination of z-coordinate and curvature achieved lowest registration error compared to the other feature combinations used by COW. The proposed method is tolerant to centerline errors because anatomical landmarks help prevent the propagation of errors across the entire colon centerline.

Evaluating patients' preferences for type of bowel preparation prior to screening CT colonography: Convenience and comfort versus sensitivity and specificity

International Nuclear Information System (INIS)

Ghanouni, A.; Halligan, S.; Taylor, S.A.; Boone, D.; Plumb, A.; Wardle, J.; Wagner, C. von

2013-01-01

Aims: To explore the relative value patients place on comfort and convenience versus test sensitivity and specificity in the context of computed tomographic colonography (CTC) screening. Materials and methods: Twenty semi-structured interviews were carried out with patients attending hospital for radiological tests unrelated to CTC. Preferences for CTC with different types of bowel preparation for CTC screening were examined and interviews were analysed thematically. The discussion guide included separate sections on CTC, bowel preparation methods (non-, reduced- and full-laxative), and sensitivity and specificity. Patients were given information on each topic in turn and asked about their views and preferences during each section. Results: Following information about the test, patients' attitudes towards CTC were positive. Following information on bowel preparation, full-laxative purgation was anticipated to cause more adverse physical and lifestyle effects than using reduced- or non-laxative preparation. However, stated preferences were approximately equally divided, largely due to patients anticipating that non-laxative preparations would reduce test accuracy (because the bowel was not thoroughly cleansed). Following information on sensitivity and specificity (which supported patients' expectations), the predominant stated preference was for full-laxative preparation. Conclusions: Patients are likely to value test sensitivity and specificity over a more comfortable and convenient preparation. Future research should test this hypothesis on a larger sample

Comparative study of colorectal carcinoma examination with four postprocessing of CT colonography

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Mingyue, Luo; Kangrong, Zhou [The 3rd Affilated Hospital Sun Yat-sen Univ. of Medical Sciences, Guangzhou (China). Dept. of Radiology

2001-10-01

Objective: To study the clinical value of colorectal carcinoma examination by comparison of different postprocessing techniques such as multiplanar reformation (MPR), CT virtual colonoscopy (CTVC), shaded surface display (SSD) and Raysum. Methods: 64 patients with colorectal carcinomas underwent volume scanning using spiral CT. MPR, CTVC, SSD and Raysum images were obtained by using 4 different software in workstation. All cases were proved by surgical or CC biotic histology. The results were compared and analyzed according to the circumferential extension, length and pathologic patterns of colorectal carcinoma with MPR, CTVC, SSD and Raysum. Results: The correction rate of determination the circumferential extension of colorectal carcinoma with MPR, CTVC, SSD and Raysum were 100.0%, 82.8%, 79.7% and 79.7%, respectively. There was significant statistical difference between MPR and CTVC; The accuracy of judging the length of carcinoma were 89.1%, 76.6%, 95.3% and 100.0%, respectively. There was statistical difference between CTVC and SSD; The accuracy of showing carcinoma pathologic patterns were 81.3%, 92.2%, 71.9% and 71.0%, respectively. There was statistical difference between CTVC and SSD, too. MPR could correctly determine the circumferential extension of colorectal carcinoma. In determination the length of carcinoma, Raysum was more accurate than SSD. CTVC could be more helpful in showing carcinoma pathologic patterns. Conclusion: There were advantages and disadvantages in colorectal carcinoma examination with MPR, CTVC, SSD and Raysum, and the combination could display colorectal carcinoma more completely and comprehensively.

Comparative study of colorectal carcinoma examination with four postprocessing of CT colonography

International Nuclear Information System (INIS)

Luo Mingyue; Zhou Kangrong

2001-01-01

Objective: To study the clinical value of colorectal carcinoma examination by comparison of different postprocessing techniques such as multiplanar reformation (MPR), CT virtual colonoscopy (CTVC), shaded surface display (SSD) and Raysum. Methods: 64 patients with colorectal carcinomas underwent volume scanning using spiral CT. MPR, CTVC, SSD and Raysum images were obtained by using 4 different software in workstation. All cases were proved by surgical or CC biotic histology. The results were compared and analyzed according to the circumferential extension, length and pathologic patterns of colorectal carcinoma with MPR, CTVC, SSD and Raysum. Results: The correction rate of determination the circumferential extension of colorectal carcinoma with MPR, CTVC, SSD and Raysum were 100.0%, 82.8%, 79.7% and 79.7%, respectively. There was significant statistical difference between MPR and CTVC; The accuracy of judging the length of carcinoma were 89.1%, 76.6%, 95.3% and 100.0%, respectively. There was statistical difference between CTVC and SSD; The accuracy of showing carcinoma pathologic patterns were 81.3%, 92.2%, 71.9% and 71.0%, respectively. There was statistical difference between CTVC and SSD, too. MPR could correctly determine the circumferential extension of colorectal carcinoma. In determination the length of carcinoma, Raysum was more accurate than SSD. CTVC could be more helpful in showing carcinoma pathologic patterns. Conclusion: There were advantages and disadvantages in colorectal carcinoma examination with MPR, CTVC, SSD and Raysum, and the combination could display colorectal carcinoma more completely and comprehensively

CT volumetric measurement of colorectal cancer helps predict tumor staging and prognosis.

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Jin Young Park

Full Text Available To evaluate feasibility of CT colonography (CTC volumetry of colorectal cancer (CRC and its correlation with disease stage and patients' survival.CTC volumetry was performed for 126 patients who underwent preoperative CTC. Reproducibility of tumor volume (Tvol between two readers was assessed. One-way ANOVA and ROC analysis evaluated correlation between Tvol and pTNM staging. ROC analysis compared diagnostic performance to predict pTNM staging between Tvol and radiologist. Kaplan-Meier test compared overall survival.Reproducibility among readers was excellent (interclass correlation = 0.9829. Mean Tvol showed an incremental trend with T stage and Tvol of pT4b stage was significantly larger than other stages (P0.05. Smaller tumor burden (≤12.85cm3, ≤T3, N0, M0 stages, and curative surgery were significantly associated with patients' longer survival (P<0.05.CT volumetry has a limited value to predict N stage; however, it may outperform the radiologist's performance when predicting pT4b and M1b stage and can be a useful prognostic marker.

Iohexol versus diatrizoate for fecal/fluid tagging during CT colonography performed with cathartic preparation: comparison of examination quality

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Kim, Bohyun; Park, Seong Ho; Hong, Gil-Sun; Lee, Jong Seok; Kim, Hyun Jin; Kim, Ah Young; Ha, Hyun Kwon [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Lee, Ju Hee [National Cancer Center, Department of Radiology, Gyeonggi-do (Korea, Republic of)

2015-06-01

We aimed to compare iohexol vs. diatrizoate as fecal/fluid tagging agents for computed tomography colonography (CTC) regarding examination quality. Forty prospective patients (M:F = 23:17; 63 ± 11.6 years) received CTC using 50 mL (350 mgI/mL) oral iohexol for tagging. Forty other indication-matched, age-matched, and sex-matched patients who underwent CTC using 100 mL diatrizoate for tagging and otherwise the same technique, were retrospectively identified. Two groups were compared regarding overall examination quality, per-patient and per-segment scores of colonic bubbles (0 [no bubbles] to 5 [the largest amount]), and the volume, attenuation, and homogeneity (untagged, layered, and homogeneous) of the residual colonic fluid. The iohexol group demonstrated a greater amount of colonic bubbles than the diatrizoate group: mean per-patient scores ± SD of 1.2 ± 0.8 vs. 0.7 ± 0.6, respectively (p = 0.003); and rates of segments showing ≥ grade 3 bubbles of 12.9 % (85/659) vs. 1.6 % (11/695), respectively (p = 0.001). Residual colonic fluid amount standardized to the colonic volume did not significantly differ: 7.2 % ± 4.2 vs. 7.8 % ± 3.7, respectively (p = 0.544). Tagged fluid attenuation was mostly comparable between groups and the fluid was homogeneously tagged in 98.7 % (224/227) vs. 99.5 % (218/219) segments, respectively (p = 0.344). Iohexol caused more colonic bubbles when used during cathartic CTC. Otherwise, examination quality was similarly adequate with both iohexol and diatrizoate. (orig.)

Preoperative evaluation of synchronous colorectal cancer using MR colonography

DEFF Research Database (Denmark)

Achiam, Michael P; Holst Andersen, Lars P; Klein, Mads

2009-01-01

RATIONALE AND OBJECTIVES: It is well known that synchronous cancers (incidence, 2%-11%) and polyps (incidence, 12%-58%) occur in patients with colorectal cancer. Magnetic resonance colonography (MRC) seems like the obvious choice as a diagnostic tool in preoperative evaluation, because...... a full conventional colonoscopy or in whom full conventional colonoscopy was not possible. MATERIALS AND METHODS: In a 13-month period, 47 patients diagnosed with rectal or sigmoid colon cancer scheduled for operation were included in the study. MRC was performed with bowel purgation either the night...... before surgery or as ambulatory MRC the week before surgery. RESULTS: Full MRC was performed in 98% of the patients. In four patients, 12 synchronous lesions (one cancer, two plaques of carcinosis, and nine adenomas) were found. One flat adenoma and five small polyps were missed by MRC and perioperative...

CT Colonography (Virtual Colonoscopy)

Science.gov (United States)

... so that the x-ray beam follows a spiral path. A special computer program processes this large ... computer generates a detailed three-dimensional (3-D) model of the colon, which the radiologist uses to ...

Cost-effectiveness of computed tomography colonography in colorectal cancer screening: a systematic review.

Science.gov (United States)

Hanly, Paul; Skally, Mairead; Fenlon, Helen; Sharp, Linda

2012-10-01

The European Code Against Cancer recommends individuals aged ≥ 50 should participate in colorectal cancer screening. CT-colonography (CTC) is one of several screening tests available. We systematically reviewed evidence on, and identified key factors influencing, cost-effectiveness of CTC screening. PubMed, Medline, and the Cochrane library were searched for cost-effectiveness or cost-utility analyses of CTC-based screening, published in English, January 1999 to July 2010. Data was abstracted on setting, model type and horizon, screening scenario(s), comparator(s), participants, uptake, CTC performance and cost, effectiveness, ICERs, and whether extra-colonic findings and medical complications were considered. Sixteen studies were identified from the United States (n = 11), Canada (n = 2), and France, Italy, and the United Kingdom (1 each). Markov state-transition (n = 14) or microsimulation (n = 2) models were used. Eleven considered direct medical costs only; five included indirect costs. Fourteen compared CTC with no screening; fourteen compared CTC with colonoscopy-based screening; fewer compared CTC with sigmoidoscopy (8) or fecal tests (4). Outcomes assessed were life-years gained/saved (13), QALYs (2), or both (1). Three considered extra-colonic findings; seven considered complications. CTC appeared cost-effective versus no screening and, in general, flexible sigmoidoscopy and fecal occult blood testing. Results were mixed comparing CTC to colonoscopy. Parameters most influencing cost-effectiveness included: CTC costs, screening uptake, threshold for polyp referral, and extra-colonic findings. Evidence on cost-effectiveness of CTC screening is heterogeneous, due largely to between-study differences in comparators and parameter values. Future studies should: compare CTC with currently favored tests, especially fecal immunochemical tests; consider extra-colonic findings; and conduct comprehensive sensitivity analyses.

Availability, Indications, and Technical Performance of Computed Tomographic Colonography: A National Survey

International Nuclear Information System (INIS)

Fisichella, V.; Hellstroem, M.

2006-01-01

Purpose: To determine the availability, indications, and technique of computed tomographic colonography (CTC) in Sweden and to investigate opinions on its future role in colon imaging. Material and Methods: In May 2004, a questionnaire on CTC was mailed to all Departments of Radiology in Sweden, and one year later a telephone interview was conducted with the departments that intended to start a CTC service. Results: Ninety-nine departments (83%) answered the questionnaire, indicating that 23/99 (23.2%) offered a CTC service. Reasons for non-implementation of CTC were lack of CTC training in 34/73 (46.6%) and non-availability of multi-detector row CT scanners in 33/73 (45.2%), while 26% were awaiting further scientific documentation on CTC. Incomplete colonoscopy was the main indication for CTC in 21/23 (91.3%) departments performing CTC. Dual positioning, room air insufflation, and thin-slice collimation were used in all the responding departments. The number of CTC studies performed varied from 1-5 (26.1%) to more than 200 (17.4%). Intravenous contrast material was routinely administered by 9/23 (39.1%) departments. Out of 30 (39.5%) departments that in 2004 intended to start CTC, 9 (30%) had done so by June 2005. A total of 32/99 (32.3%) departments had therefore started CTC by June 2005. Half of the departments that replied believed that CTC would absolutely or probably replace barium enema in the future. Conclusion: The survey shows relatively limited diffusion of CTC practice in Sweden, with approximately one-third of radiology departments offering a CTC service, mostly on a small scale. A wider dissemination of CTC requires further scientific documentation of its capability, intensified educational efforts, and additional funding

The diagnostic value of multiplanar reconstruction on MDCT colonography for the preoperative staging of colorectal cancer

International Nuclear Information System (INIS)

Jin, Kwang Nam; Kim, Se Hyung; Lee, Jae Young; Lee, Jeong Min; Han, Joon Koo; Choi, Byung Ihn; Shin, Kyung-Sook

2006-01-01

The purpose of this study was to determine whether multiplanar reconstruction (MPR) images can improve the accuracy of MDCT-based colorectal cancer preoperative staging by receiver-operating characteristic (ROC) analysis. Fifty-five patients with colorectal cancer underwent contrast-enhanced CT colonography using an 8- or 16-row scanner. Two separate interval reviews of the axial MDCT datasets with/without MPR images (coronal and sagittal) were performed independently by two radiologists blinded to both the colonoscopic and histopathologic results. At each review session, the radiologists were asked to determine the colorectal cancer TNM stage within the context of differentiating ≤T3 from T4, N0 from ≥N1 and M0 from M1 using a five-point confidence scale. The radiologists' performance for staging the colorectal cancer using axial CT datasets with/without MPR images was evaluated using ROC analysis. Sensitivities, specificities and interobserver agreement were assessed. When MPR images were added, significant improvement was achieved by both radiologists for differentiating N0 from ≥N1 in terms of both A Z (0.651 to 0.769; 0.573 to 0.713) and specificity (26.7 to 69.2%; 23.1 to 76.9%) (P 0.05), but a significant improvement in the specificity (70 to 90%; 80 to 92%) was achieved by one radiologist (P<0.05). In terms of the M staging, a significant improvement in the Az (0.844 to 0.996) was observed for the combined interpretation of the axial and MPR images by one radiologist (P<0.05). Furthermore, substantial or almost perfect interobserver agreement was achieved for all TNM stagings for the combined interpretations (κ=0.641-0.866), whereas only fair to substantial agreement was achieved for the axial images alone (κ=0.337-0.707). In conclusion, the combined interpretation of the axial and MPR MDCT images significantly improved the local staging of colorectal cancer compared with assessments based on axial images alone. (orig.)

A review of patient dose and optimisation methods in adult and paediatric CT scanning

International Nuclear Information System (INIS)

Dougeni, E.; Faulkner, K.; Panayiotakis, G.

2012-01-01

Highlights: ► CT scanning frequency has grown with the development of new clinical applications. ► Up to 32-fold dose variation was observed for similar type of procedures. ► Scanning parameters should be optimised for patient size and clinical indication. ► Cancer risks knowledge amongst physicians of certain specialties was poor. ► A significant number of non-indicated CT scans could be eliminated. - Abstract: An increasing number of publications and international reports on computed tomography (CT) have addressed important issues on optimised imaging practice and patient dose. This is partially due to recent technological developments as well as to the striking rise in the number of CT scans being requested. CT imaging has extended its role to newer applications, such as cardiac CT, CT colonography, angiography and urology. The proportion of paediatric patients undergoing CT scans has also increased. The published scientific literature was reviewed to collect information regarding effective dose levels during the most common CT examinations in adults and paediatrics. Large dose variations were observed (up to 32-fold) with some individual sites exceeding the recommended dose reference levels, indicating a large potential to reduce dose. Current estimates on radiation-related cancer risks are alarming. CT doses account for about 70% of collective dose in the UK and are amongst the highest in diagnostic radiology, however the majority of physicians underestimate the risk, demonstrating a decreased level of awareness. Exposure parameters are not always adjusted appropriately to the clinical question or to patient size, especially for children. Dose reduction techniques, such as tube-current modulation, low-tube voltage protocols, prospective echocardiography-triggered coronary angiography and iterative reconstruction algorithms can substantially decrease doses. An overview of optimisation studies is provided. The justification principle is discussed along

Diagnostic Performance of Computed Tomography Colonography and Colonoscopy: A Prospective and Validated Analysis of 231 Paired Examinations

International Nuclear Information System (INIS)

Arnesen, R.B.; Benzon, E. von; Adamsen, S.; Svendsen, L.B.; Raaschou, H.O.; Hart Hansen, O.

2007-01-01

Background: Detection of colorectal tumors with computed tomography colonography (CTC) is an alternative to conventional colonoscopy (CC), and clarification of the diagnostic performance is essential for cost-effective use of both technologies. Purpose: To evaluate the diagnostic performance of CTC compared with CC. Material and Methods: 231 consecutive CTCs were performed prior to same-day scheduled CC. The radiologist and endoscopists were blinded to each other's findings. Patients underwent a polyethylene glycol bowel preparation, and were scanned in prone and supine positions using a single-detector helical CT scanner and commercially available software for image analysis. Findings were validated (matched) in an unblinded comparison with video-recordings of the CCs and re-CCs in cases of doubt. Results: For patients with polyps 5 mm and 10 mm, the sensitivity was 69% (95% CI 58-80%) and 81% (68-94%), and the specificity was 91% (84-98%) and 98% (93-100%), respectively. For detection of polyps 5 mm and 10 mm, the sensitivity was 66% (57-75%) and 77% (65-89%). A flat, elevated low-grade carcinoma was missed by CTC. One cancer relapse was missed by CC, and a cecal cancer was missed by an incomplete CC and follow-up double-contrast barium enema. Conclusion: CC was superior to CTC and should remain first choice for the diagnosis of colorectal polyps. However, for diagnosis of lesions 10 mm, CTC and CC should be considered as complementary methods

ACR Appropriateness Criteria® Colorectal Cancer Screening.

Science.gov (United States)

Moreno, Courtney; Kim, David H; Bartel, Twyla B; Cash, Brooks D; Chang, Kevin J; Feig, Barry W; Fowler, Kathryn J; Garcia, Evelyn M; Kambadakone, Avinash R; Lambert, Drew L; Levy, Angela D; Marin, Daniele; Peterson, Christine M; Scheirey, Christopher D; Smith, Martin P; Weinstein, Stefanie; Carucci, Laura R

2018-05-01

This review summarizes the relevant literature regarding colorectal screening with imaging. For individuals at average or moderate risk for colorectal cancer, CT colonography is usually appropriate for colorectal cancer screening. After positive results on a fecal occult blood test or immunohistochemical test, CT colonography is usually appropriate for colorectal cancer detection. For individuals at high risk for colorectal cancer (eg, hereditary nonpolyposis colorectal cancer, ulcerative colitis, or Crohn colitis), optical colonoscopy is preferred because of its ability to obtain biopsies to detect dysplasia. After incomplete colonoscopy, CT colonography is usually appropriate for colorectal cancer screening for individuals at average, moderate, or high risk. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment. Copyright © 2018 American College of Radiology. Published by Elsevier Inc. All rights reserved.

CT colonography with limited bowel preparation: prospective assessment of patient experience and preference in comparison to optical colonoscopy with cathartic bowel preparation

International Nuclear Information System (INIS)

Jensch, Sebastiaan; Bipat, Shandra; Vries, Ayso H. de; Heutinck, Anneke; Stoker, Jaap; Peringa, Jan; Montauban van Swijndregt, Alexander D.; Dekker, Evelien; Baak, Lubbertus C.

2010-01-01

The purpose of this study was to prospectively compare participant experience and preference of limited preparation computed tomography colonography (CTC) with full-preparation colonoscopy in a consecutive series of patients at increased risk of colorectal cancer. CTC preparation comprised 180 ml diatrizoate meglumine, 80 ml barium and 30 mg bisacodyl. For the colonoscopy preparation 4 l of polyethylene glycol solution was used. Participants' experience and preference were compared using the Wilcoxon signed rank test and the chi-squared test, respectively. Associations between preference and experience parameters for the 173 participants were determined by logistic regression. Diarrhoea occurred in 94% of participants during CTC preparation. This side effect was perceived as severely or extremely burdensome by 29%. Nonetheless, the total burden was significantly lower for the CTC preparation than for colonoscopy (9% rated the CTC preparation as severely or extremely burdensome compared with 59% for colonoscopy; p<0.001). Participants experienced significantly more pain, discomfort and total burden with the colonoscopy procedure than with CTC (p<0.001). After 5 weeks, 69% preferred CTC, 8% were indifferent and 23% preferred colonoscopy (p<0.001). A burdensome colonoscopy preparation and pain at colonoscopy were associated with CTC preference (p<0.04). In conclusion, participants' experience and preference were rated in favour of CTC with limited bowel preparation compared with full-preparation colonoscopy. (orig.)

Common findings and pseudolesions at computed tomography colonography: pictorial essay

International Nuclear Information System (INIS)

Atzingen, Augusto Castelli von; Tiferes, Dario Ariel; Matsumoto, Carlos Alberto; Nunes, Thiago Franchi; Maia, Marcos Vinicius Alvim Soares; D'Ippolito, Giuseppe

2012-01-01

Computed tomography colonography is a minimally invasive method for screening for polyps and colorectal cancer, with extremely unusual complications, increasingly used in the clinical practice. In the last decade, developments in bowel preparation, imaging, and in the training of investigators have determined a significant increase in the method sensitivity. Images interpretation is accomplished through a combined analysis of two-dimensional source images and several types of three-dimensional renderings, with sensitivity around 96% in the detection of lesions with dimensions equal or greater than 10 mm in size, when analyzed by experienced radiologists. The present pictorial essay includes examples of diseases and pseudolesions most frequently observed in this type of imaging study. The authors present examples of flat and polypoid lesions, benign and malignant lesions, diverticular disease of the colon, among other conditions, as well as pseudolesions, including those related to inappropriate bowel preparation and misinterpretation. (author)

Common findings and pseudolesions at computed tomography colonography: pictorial essay

Energy Technology Data Exchange (ETDEWEB)

Atzingen, Augusto Castelli von [Clinical Radiology, Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil); Tiferes, Dario Ariel; Matsumoto, Carlos Alberto; Nunes, Thiago Franchi; Maia, Marcos Vinicius Alvim Soares [Abdominal Imaging Section, Department of Imaging Diagnosis - Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil); D' Ippolito, Giuseppe, E-mail: giuseppe_dr@uol.com.br [Department of Imaging Diagnosis, Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil)

2012-05-15

Computed tomography colonography is a minimally invasive method for screening for polyps and colorectal cancer, with extremely unusual complications, increasingly used in the clinical practice. In the last decade, developments in bowel preparation, imaging, and in the training of investigators have determined a significant increase in the method sensitivity. Images interpretation is accomplished through a combined analysis of two-dimensional source images and several types of three-dimensional renderings, with sensitivity around 96% in the detection of lesions with dimensions equal or greater than 10 mm in size, when analyzed by experienced radiologists. The present pictorial essay includes examples of diseases and pseudolesions most frequently observed in this type of imaging study. The authors present examples of flat and polypoid lesions, benign and malignant lesions, diverticular disease of the colon, among other conditions, as well as pseudolesions, including those related to inappropriate bowel preparation and misinterpretation. (author)

Magnetic resonance colonography without bowel cleansing using oral and rectal stool softeners (fecal cracking) - a feasibility study

International Nuclear Information System (INIS)

Ajaj, Waleed; Lauenstein, Thomas C.; Kuehle, Christiane; Herborn, Christoph U.; Goehde, Susanne C.; Schneemann, Hubert; Ruehm, Stefan G.; Goyen, Mathias

2005-01-01

The aim of our study was to assess the effect of oral and rectal stool softeners on dark-lumen magnetic resonance (MR) colonography without bowel cleansing. Ten volunteers underwent MR colonography without colonic cleansing. A baseline examination was performed without oral or rectal administration of stool softeners. In a second set, volunteers ingested 60 ml of lactulose 24 h prior to MR examination. In a third examination, water as a rectal enema was replaced by a solution of 0.5%-docusate sodium (DS). A fourth MR examination was performed, in conjunction with both oral administration of lactulose and rectal application of DS. A T1-weighted data set was acquired at scanning times of 0, 5 and 10 min after colonic filling. A fourth data set was acquired 75 s after i.v. injection of contrast agent. Signal intensity of stool was calculated for all colonic segments. Without oral ingestion of lactulose or rectal enema with DS stool signal intensity was high and did not decrease over time. However, lactulose and DS caused a decrease in stool signal intensity. Both substances together led to a decreasing signal intensity of feces. Combination of lactulose and DS provided the lowest signal intensity of stool. Thus, feces could hardly be distinguished from dark rectal enema allowing for the assessment of the colonic wall. (orig.)

Assessment of colonic disease by multi-slice CT pneumocolon after incomplete colonoscopy

International Nuclear Information System (INIS)

Zhao Zehua; Liu Wenjin; Xu Songsen; Wang Kang; Wang Weizhong

2004-01-01

Objective: To evaluate the use of preoperative MSCT in patients with clinically suspected colorectal disease after incomplete colonoscopy. Methods: After incomplete colonoscopy, 31 patients underwent MSCT before and after intravenous injection of iodinated contrast agent. CT virtual colonography (CTVC), multiplanar reformation (MPR), shaded surface display (SSD), and Raysum images were obtained by using 4 different software in workstation. The results of MSCT were compared with the findings of colonoscopy, intraoperative colon palpation, and postoperative pathology. Results: After incomplete colonoscopy, MSCT was successfully performed in all 31 cases. Postoperative pathology revealed 22 colorectal cancers (one synchronous cancers, two with polyps) and 9 benign disease. 22 colonic carcinomas were all correctly diagnosed by MSCT (including synchronous disease), 2 benign diseases were misdiagnosed as malignancy, and one polyp was missed. Conclusion: MSCT is a feasible and useful method for evaluating the entire colon before surgery in patients with occlusive disease. (author)

Adaptive statistical iterative reconstruction and Veo: assessment of image quality and diagnostic performance in CT colonography at various radiation doses.

Science.gov (United States)

Yoon, Min A; Kim, Se Hyung; Lee, Jeong Min; Woo, Hyoun Sik; Lee, Eun Sun; Ahn, Se Jin; Han, Joon Koo

2012-01-01

To evaluate the diagnostic performance of computed tomography (CT) colonography (CTC) reconstructed with different levels of adaptive statistical iterative reconstruction (ASiR, GE Healthcare) and Veo (model-based iterative reconstruction, GE Healthcare) at various tube currents in detection of polyps in porcine colon phantoms. Five porcine colon phantoms with 46 simulated polyps were scanned at different radiation doses (10, 30, and 50 mA s) and were reconstructed using filtered back projection (FBP), ASiR (20%, 40%, and 60%) and Veo. Eleven data sets for each phantom (10-mA s FBP, 10-mA s 20% ASiR, 10-mA s 40% ASiR, 10-mA s 60% ASiR, 10-mA s Veo, 30-mA s FBP, 30-mA s 20% ASiR, 30-mA s 40% ASiR, 30-mA s 60% ASiR, 30-mA s Veo, and 50-mA s FBP) yielded a total of 55 data sets. Polyp detection sensitivity and confidence level of 2 independent observers were evaluated with the McNemar test, the Fisher exact test, and receiver operating characteristic curve analysis. Comparative analyses of overall image quality score, measured image noise, and interpretation time were also performed. Per-polyp detection sensitivities and specificities were highest in 10-mA s Veo, 30-mA s FBP, 30-mA s 60% ASiR, and 50-mA s FBP (sensitivity, 100%; specificity, 100%). The area-under-the-curve values for the overall performance of each data set was also highest (1.000) at 50-mA s FBP, 30-mA s FBP, 30-mA s 60% ASiR, and 10-mA s Veo. Images reconstructed with ASiR showed statistically significant improvement in per-polyp detection sensitivity as the percent level of per-polyp sensitivity increased (10-mA s FBP vs 10-mA s 20% ASiR, P = 0.011; 10-mA s FBP vs 10-mA s 40% ASiR, P = 0.000; 10-mA s FBP vs 10-mA s 60% ASiR, P = 0.000; 10-mA s 20% ASiR vs 40% ASiR, P = 0.034). Overall image quality score was highest at 30-mA s Veo and 50-mA s FBP. The quantitative measurement of the image noise was lowest at 30-mA s Veo and second lowest at 10-mA s Veo. There was a trend of decrease in time

Intra-individual comparison of magnesium citrate and sodium phosphate for bowel preparation at CT colonography: Automated volumetric analysis of residual fluid for quality assessment

International Nuclear Information System (INIS)

Bannas, P.; Bakke, J.; Munoz del Rio, A.; Pickhardt, P.J.

2014-01-01

Aim: To perform an objective, intra-individual comparison of residual colonic fluid volume and attenuation associated with the current front-line laxative magnesium citrate (MgC) versus the former front-line laxative sodium phosphate (NaP) at CT colonography (CTC). Materials and methods: This retrospective Health Insurance and Portability and Accountability Act-compliant study had institutional review board approval; informed consent was waived. The study cohort included 250 asymptomatic adults (mean age at index 56.1 years; 124 male/126 female) who underwent CTC screening twice over a 5 year interval. Colon catharsis at initial and follow-up screening employed single-dose NaP and double-dose MgC, respectively, allowing for intra-patient comparison. Automated volumetric analysis of residual colonic fluid volume and attenuation was performed on all 500 CTC studies. Colonic fluid volume <200 ml and mean attenuation between 300–900 HU were considered optimal. Paired t-test and McNemar's test were used to compare differences. Results: Residual fluid volumes <200 ml were recorded in 192 examinations (76.8%) following MgC and in 204 examinations (81.6%) following NaP (p = 0.23). The mean total residual fluid volume was 155 ± 114 ml for MgC and 143 ± 100 ml for NaP (p = 0.01). The attenuation range of 300–900 HU was significantly more frequent for MgC (n = 220, 88%) than for NaP (n = 127, 50.8%; p < 0.001). Mean fluid attenuation was significantly lower for MgC (700 ± 165 HU) than for NaP (878 ± 155 HU; p < 0.001). Concomitant presence of both optimal fluid volume and attenuation was significantly more frequent for MgC 65.2% than for NaP (38%; p < 0.001). Conclusions: Objective intra-individual comparison using automated volumetric analysis suggests that the replacement of NaP by MgC as the front-line laxative for CTC has not compromised overall examination quality. - Highlights: • Automated volumetric analysis provides

Efficacy of Barium-Based Fecal Tagging for CT Colonography: a Comparison between the Use of High and Low Density Barium Suspensions in a Korean Population - a Preliminary Study

Science.gov (United States)

Kim, Min Ju; Lee, Seung Soo; Byeon, Jeong-Sik; Choi, Eugene K.; Kim, Jung Hoon; Kim, Yeoung Nam; Kim, Ah Young; Ha, Hyun Kwon

2009-01-01

Objective This preliminarily study was designed to determine and to compare the efficacy of two commercially available barium-based fecal tagging agents for CT colonography (CTC) (high-density [40% w/v] and low-density [4.6% w/v] barium suspensions) in a population in Korea. Materials and Methods In a population with an identified with an average-risk for colorectal cancer, 15 adults were administered three doses of 20 ml 40% w/v barium for fecal tagging (group I) and 15 adults were administered three doses of 200 ml 4.6% w/v barium (group II) for fecal tagging. Excluding five patients in group I and one patient in group II that left the study, ten patients in group I and 14 patients in group II were finally included in the analysis. Two experienced readers evaluated the CTC images in consensus regarding the degree of tagging of stool pieces 6 mm or larger. Stool pieces were confirmed with the use of standardized CTC criteria or the absence of matched lesions as seen on colonoscopy. The rates of complete fecal tagging were analyzed on a per-lesion and a per-segment basis and were compared between the patients in the two groups. Results Per-lesion rates of complete fecal tagging were 52% (22 of 42; 95% CI, 37.7-66.6%) in group I and 78% (28 of 36; 95% CI, 61.7-88.5%) in group II. The difference between the two groups did not reach statistical significance (p = 0.285). The per-segment rates of complete tagging were 33% (6 of 18; 95% CI, 16.1%-56.4%) in group I and 60% (9 of 15; 95% CI, 35.7%-80.3%) in group II; again, the difference between the two groups did not reach statistical significance (p = 0.171). Conclusion Barium-based fecal tagging using both the 40% w/v and the 4.6% w/v barium suspensions showed moderate tagging efficacy. The preliminary comparison did not demonstrate a statistically significant difference in the tagging efficacy between the use of the two tagging agents, despite the tendency toward better tagging with the use of the 4.6% w/v barium

Your Radiologist Explains CT Colonography

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Your Radiologist Explains CT Colonography

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Full Text Available ... for the exam to be performed with the most accuracy. If you have any questions about the ... go back to work the same day in most cases. Perhaps you might have some concerns about ...

Your Radiologist Explains CT Colonography

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Full Text Available ... Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI Story Radiology and You Take our ... Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI Story Radiology and You Take our ...

Your Radiologist Explains CT Colonography

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Spotlight Recently posted: How ...

Your Radiologist Explains CT Colonography

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... virtual colonoscopy. Virtual colonoscopy is a diagnostic imaging test that is used to screen the large intestine ...

Time-efficient CT colonography interpretation using an advanced image-gallery-based, computer-aided ''first-reader'' workflow for the detection of colorectal adenomas

International Nuclear Information System (INIS)

Mang, Thomas; Ringl, Helmut; Weber, Michael; Mueller-Mang, Christina; Hermosillo, Gerardo; Wolf, Matthias; Bogoni, Luca; Salganicoff, Marcos; Raykar, Vikas; Graser, Anno

2012-01-01

To assess the performance of an advanced ''first-reader'' workflow for computer-aided detection (CAD) of colorectal adenomas ≥ 6 mm at computed tomographic colonography (CTC) in a low-prevalence cohort. A total of 616 colonoscopy-validated CTC patient-datasets were retrospectively reviewed by a radiologist using a ''first-reader'' CAD workflow. CAD detections were presented as galleries of six automatically generated two-dimensional (2D) and three-dimensional (3D) images together with interactive 3D target views and 2D multiplanar views of the complete dataset. Each patient-dataset was interpreted by initially using CAD image-galleries followed by a fast 2D review to address unprompted colonic areas. Per-patient, per-polyp, and per-adenoma sensitivities were calculated for lesions ≥ 6 mm. Statistical testing employed Fisher's exact and McNemar tests. In 91/616 patients, 131 polyps (92 adenomas, 39 non-adenomas) ≥ 6 mm and two cancers were identified by reference standard. Using the CAD gallery-based first-reader workflow, the radiologist detected all adenomas ≥ 10 mm (34/34) and cancers. Per-patient and polyp sensitivities for lesions ≥ 6 mm were 84.3 % (75/89), and 83.2 % (109/131), respectively, with 89.1 % (57/64) and 85.9 % (79/92) for adenomas. Overall specificity was 95.6 % (504/527). Mean interpretation time was 3.1 min per patient. A CAD algorithm, applied in an image-gallery-based first-reader workflow, can substantially decrease reading times while enabling accurate detection of colorectal adenomas in a low-prevalence population. (orig.)

Perioperative Colonic Evaluation in Patients with Rectal Cancer; MR Colonography Versus Standard Care

DEFF Research Database (Denmark)

Achiam, Michael Patrick; Løgager, Vibeke; Lund Rasmussen, Vera

2015-01-01

RATIONALE AND OBJECTIVES: Preoperative colonic evaluation is often inadequate because of cancer stenosis making a full conventional colonoscopy (CC) impossible. In several studies, cancer stenosis has been shown in up to 16%-34% of patients with colorectal cancer. The purpose of this study...... was to prospectively evaluate the completion rate of preoperative colonic evaluation and the quality of perioperative colonic evaluation using magnetic resonance colonography (MRC) in patients with rectal cancer. MATERIALS AND METHODS: Patients diagnosed with rectal cancer were randomized to either group A: standard...... preoperative diagnostic work-up or group B: preoperative MR diagnostic work-up (standard preoperative diagnostic work-up + MRC). A complete and adequate perioperative clean-colon evaluation (PCE) was defined as either a complete preoperative colonic evaluation or a complete colonic evaluation within 3 months...

REVIEW ARTICLE REVI Current trends in virtual colonoscopy

African Journals Online (AJOL)

polypectomy). However it is regarded as an invasive procedure and has potentially serious complications. Computed tomography (CT) colonography may have a unique role in colorectal cancer screening. The main ... André du Plessis, MB ChB.

Dual-energy index value of luminal air in fecal-tagging computed tomography colonography: findings and impact on electronic cleansing.

Science.gov (United States)

Cai, Wenli; Zhang, Da; Lee, June-Goo; Shirai, Yu; Kim, Se Hyung; Yoshida, Hiroyuki

2013-01-01

The purpose of our study was to measure the dual-energy index (DEI) value of colonic luminal air in both phantom and clinical fecal-tagging dual-energy computed tomography (CT) colonography (DE-CTC) images and to demonstrate its impact on dual-energy electronic cleansing. For the phantom study, a custom-ordered colon phantom was scanned by a dual-energy CT scanner (SOMATON Definition Flash; Siemens Healthcare, Forchheim, Germany) at two photon energies: 80 and 140 kVp. Before imaging, the phantom was filled with a 300-mL mixture of simulated fecal materials tagged by a nonionic iodinated contrast agent at three contrast concentrations: 20, 40, and 60 mg/mL. Ten regions-of-interest (ROIs) were randomly placed in each of the colonic luminal air, abdominal fat, bony structure, and tagged material in each scan. For the clinical study, 22 DE-CTC (80 and 140 kVp) patient cases were collected, who underwent a low-fiber, low-residue diet bowel preparation and orally administered iodine-based fecal tagging. Twenty ROIs were randomly placed in each of the colonic luminal air, abdominal fat, abdominal soft tissue, and tagged fecal material in each scan. For each ROI, the mean CT values in both 80- and 140-kVp images were measured, and then its DEI was calculated. In the phantom study, the mean DEI values of luminal air were 0.270, 0.298, 0.386, and 0.402 for the four groups of tagging conditions: no tagged material and tagged with three groups of contrast concentrations at 20, 40, and 60 mg/mL. In the clinical study, the mean DEI values were 0.341, -0.012, -0.002, and 0.188 for colonic luminal air, abdominal fat, abdominal soft tissue, and tagged fecal material, respectively. In our study, we observed that the DEI values of colonic luminal air in DE-CTC images (>0.10) were substantially higher than the theoretical value of 0.0063. In addition, the observed DEI values of colonic luminal air were significantly higher than those of soft tissue. These findings have an important

Magnetic resonance colonography versus colonoscopy as a diagnostic investigation for colorectal cancer: a meta-analysis

International Nuclear Information System (INIS)

Purkayastha, S.; Tekkis, P.P.; Athanasiou, T.; Aziz, O.; Negus, R.; Gedroyc, W.; Darzi, A.W.

2005-01-01

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

Feasibility of using automated insufflated carbon dioxide (CO2) for luminal distension in 3.0 T MR colonography

International Nuclear Information System (INIS)

Zijta, F.M.; Nederveen, A.J.; Jensch, S.; Florie, J.; Bipat, S.; Paardt, M.P. van der; Montauban van Swijndregt, A.D.; Stoker, J.

2012-01-01

Purpose: Primary aim of our study was to prospectively evaluate the feasibility of automated carbon dioxide (CO 2 ) delivery as luminal distending agent in 3.0 T MR colonography. Materials and methods: Rectally insufflated CO 2 was evaluated in four groups with different bowel preparation (A–D). Bowel preparation regimes were: gadolinium-based tagging (A), bowel purgation (B), barium-based tagging (C) and iodine-based tagging (D). Supine (3D)T1w-FFE and (2D)T2w-SSFSE series were acquired. Each colon was divided into six segments (cecum S1–rectum S6). Two observers independently assessed the presence of artefacts, diagnostic confidence and segmental colonic distension. Also characteristics of the residual stool (presence, composition and signal-intensity) were assessed per segment. Discomfort was assessed with questionnaires. Results: Fourteen healthy subjects were included. Colonic distension by means of rectally insufflated CO 2 was not associated with susceptibility artefacts. Overall image quality was affected by the presence of bowel motion-related artefacts: none of the segments in 3DT1w-series and 10/84 (12%) colon segments in 2DT2w-series were rated artefact-free by both observers. Diagnostic confidence ratings were superior for the 2DT2w-SSFSE series. Overall bowel distension was rated adequate to optimal in 312/336 (93%) colon segments. Conclusion: MR colonography at 3.0 T using carbon dioxide (CO 2 ) for colonic distension is technically feasible. The presence of intraluminal CO 2 did not result in susceptibility artefacts, although overall image quality was influenced by artefacts.

Dose and dose reduction in computed tomography; Dosis und Dosisreduktion in der Computertomografie

Energy Technology Data Exchange (ETDEWEB)

Lell, Michael [Klinikum Nuernberg (Germany). Inst. fuer Radiologie und Nuklearmedizin; Paracelsus Medical Univ. Nuernberg (Germany); Wucherer, Michael [Klinikum Nuernberg (Germany). Inst. fuer Medizinische Physik; Kachelriess, Marc [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany)

2017-06-15

CT is widely used in medical imaging due to high availability, relatively low cost, and excellent diagnostic yield. Newer applications like coronary CTA, CT colonography, and CT perfusion imaging are integrated in clinical pathways. Although there is a high level of consensus that the benefits of CT exceeds the risks of radiation exposure for appropriate indications, concerns have been raised regarding the potential of cancer induction. Keeping dose as low as reasonably achievable remains the most important task. Dose reduction strategies are presented and discussed.

Many unexpected abdominal findings on staging computed tomography in patients with colorectal cancer

DEFF Research Database (Denmark)

Holmsted, Kim; Nørring, Keld; Laustrup, Lene Collatz

2011-01-01

; an issue that was previously studied in relation to CT colonography, but not in relation to staging CT with intravenous contrast in CRC patients. The aim of the present study was to evaluate the number and significance of such unexpected findings on staging CTs in CRC patients.......Computed tomography (CT) was proven to be superior to preoperative abdominal ultrasound in the preoperative setting for detection of hepatic metastases from colorectal cancer (CRC). The higher sensitivity of CT has resulted in a number of unexpected abdominal findings of varying importance...

Virtual Colonoscopy Screening With Ultra Low-Dose CT and Less-Stressful Bowel Preparation: A Computer Simulation Study

Science.gov (United States)

Wang, Jing; Wang, Su; Li, Lihong; Fan, Yi; Lu, Hongbing; Liang, Zhengrong

2008-10-01

Computed tomography colonography (CTC) or CT-based virtual colonoscopy (VC) is an emerging tool for detection of colonic polyps. Compared to the conventional fiber-optic colonoscopy, VC has demonstrated the potential to become a mass screening modality in terms of safety, cost, and patient compliance. However, current CTC delivers excessive X-ray radiation to the patient during data acquisition. The radiation is a major concern for screening application of CTC. In this work, we performed a simulation study to demonstrate a possible ultra low-dose CT technique for VC. The ultra low-dose abdominal CT images were simulated by adding noise to the sinograms of the patient CTC images acquired with normal dose scans at 100 mA s levels. The simulated noisy sinogram or projection data were first processed by a Karhunen-Loeve domain penalized weighted least-squares (KL-PWLS) restoration method and then reconstructed by a filtered backprojection algorithm for the ultra low-dose CT images. The patient-specific virtual colon lumen was constructed and navigated by a VC system after electronic colon cleansing of the orally-tagged residue stool and fluid. By the KL-PWLS noise reduction, the colon lumen can successfully be constructed and the colonic polyp can be detected in an ultra low-dose level below 50 mA s. Polyp detection can be found more easily by the KL-PWLS noise reduction compared to the results using the conventional noise filters, such as Hanning filter. These promising results indicate the feasibility of an ultra low-dose CTC pipeline for colon screening with less-stressful bowel preparation by fecal tagging with oral contrast.

Test-positive rate at CT colonography is increased by rectal bleeding and/or unexplained weight loss, unlike other common gastrointestinal symptoms

International Nuclear Information System (INIS)

Hock, D.; Materne, R.; Ouhadi, R.; Mancini, I.; Aouachria, S.A.; Nchimi, A.

2015-01-01

We evaluated the rate of significant colonic and extra-colonic abnormalities at computed tomography colonography (CTC), according to symptoms and age. We retrospectively evaluated 7361 consecutive average-risk subjects (3073 males, average age: 60.3 ± 13.9; range 18–96 years) for colorectal cancer (CRC) who underwent CTC. They were divided into three groups according to clinical symptoms: 1343 asymptomatic individuals (group A), 899 patients with at least one “alarm” symptom for CRC, including rectal bleeding and unexplained weight loss (group C), and 5119 subjects with other gastrointestinal symptoms (group B). Diagnostic and test-positive rates of CTC were established using optical colonoscopy (OC) and/or surgery as reference standard. In addition, clinically significant extra-colonic findings were noted. 903 out of 7361 (12%, 95% confidence interval (CI) 0.11–0.13) subjects had at least one clinically significant colonic finding at CTC. CTC true positive fraction and false positive fraction were respectively 637/642 (99.2%, 95%CI 0.98–0.99) and 55/692 (7.95%, 95%CI 0.05–0.09). The pooled test-positive rate in group C (138/689, 20.0%, 95%CI 0.17–0.23) was significantly higher than in both groups A (79/1343, 5.9%, 95%CI 0.04–0.07) and B (420/5329, 7.5%, 95%CI 0.07–0.08) (p < 0.001). Aging and male gender were associated to a higher test positive rate. The rate of clinically significant extra-colonic findings was significantly higher in group C (44/689, 6.4%, 95%CI 0.04–0.08) versus groups A (26/1343, 1.9%, 95%CI 0.01–0.02) and B (64/5329, 1.2%, 95%CI 0.01–0.02) (p < 0.001). Both test-positive and significant extra-colonic finding rates at CTC are significantly increased in the presence of “alarm” gastrointestinal symptoms especially in older patients

Registration of central paths and colonic polyps between supine and prone scans in computed tomography colonography: Pilot study

International Nuclear Information System (INIS)

Li Ping; Napel, Sandy; Acar, Burak; Paik, David S.; Jeffrey, R. Brooke Jr.; Beaulieu, Christopher F.

2004-01-01

Computed tomography colonography (CTC) is a minimally invasive method that allows the evaluation of the colon wall from CT sections of the abdomen/pelvis. The primary goal of CTC is to detect colonic polyps, precursors to colorectal cancer. Because imperfect cleansing and distension can cause portions of the colon wall to be collapsed, covered with water, and/or covered with retained stool, patients are scanned in both prone and supine positions. We believe that both reading efficiency and computer aided detection (CAD) of CTC images can be improved by accurate registration of data from the supine and prone positions. We developed a two-stage approach that first registers the colonic central paths using a heuristic and automated algorithm and then matches polyps or polyp candidates (CAD hits) by a statistical approach. We evaluated the registration algorithm on 24 patient cases. After path registration, the mean misalignment distance between prone and supine identical anatomic landmarks was reduced from 47.08 to 12.66 mm, a 73% improvement. The polyp registration algorithm was specifically evaluated using eight patient cases for which radiologists identified polyps separately for both supine and prone data sets, and then manually registered corresponding pairs. The algorithm correctly matched 78% of these pairs without user input. The algorithm was also applied to the 30 highest-scoring CAD hits in the prone and supine scans and showed a success rate of 50% in automatically registering corresponding polyp pairs. Finally, we computed the average number of CAD hits that need to be manually compared in order to find the correct matches among the top 30 CAD hits. With polyp registration, the average number of comparisons was 1.78 per polyp, as opposed to 4.28 comparisons without polyp registration

Effect of intravenous Buscopan on colonic distention during computed tomography colonography

International Nuclear Information System (INIS)

Behrens, C.; Stevenson, G.; Eddy, R.; Mathieson, J.

2008-01-01

This study was designed to assess whether spasmolytic drugs are helpful in computed tomography colonography (CTC), as there is conflict in the literature. We assessed retrospectively in a blinded fashion colonic distention in 149 individuals, one-half of whom had intravenous (IV) Buscopan during CTC. Colonic segments (n = 1788) were analyzed by 2 observers, and allocated to one of 4 grades of the distention. We also recorded the presence and severity of diverticular disease. Buscopan increased the likelihood of optimal distention by an OR of 5 when considering individual colonic segments from ascending colon to sigmoid, with little effect on rectum or cecum. Considering the colon as a whole, the OR of optimal distention occurring throughout the entire colon was 7.9 times greater with Buscopan than without. In the sigmoid colon, Buscopan had a significantly greater impact on obtaining optimal distention in those with diverticulosis than in those without. Buscopan increases the probability of obtaining optimal distention during CTC, especially in the sigmoid colon in diverticular disease. Buscopan is likely to improve polyp conspicuity and patient comfort, and to reduce both the examination time during and the interpretation time We recommend routine use of Buscopan during CTC. (author)

Diagnosis of colorectal endometriosis: contribution of contrast enhanced MR-colonography

International Nuclear Information System (INIS)

Scardapane, Arnaldo; Lorusso, Filomenamila; Stabile Ianora, Amato Antonio; Lasciarrea, Maurilia; Angelelli, Giuseppe; Bettocchi, Stefano; Vimercati, Antonella; Ceci, Oronzo

2011-01-01

To investigate the contribution of contrast-enhanced MR-colonography (CE-MR-C) for the diagnosis of intestinal endometriosis. One hundred and four women with suspected endometriosis were prospectively enrolled. All patients were subjected to MRI consisting of two phases: pelvic high-resolution MRI (HR-MRI) followed by CE-MR-C after colonic distension using a 1.5-liter water enema and injection of 0.15 ml/kg of 0.5 M gadolinium-DTPA with T1w high-resolution isotropic volume (THRIVE) and balanced turbo field echo (BTFE) images. HR-MRI and CE-MR-C were considered as two datasets, which were independently reviewed by two radiologists with 12 and 2 years' experience respectively. The presence of deep pelvic endometriotic lesions with particular attention to colorectal involvement was recorded. MRI findings correlated with laparoscopy in all cases. Thanks to CE-MR-C images, sensitivity, specificity, PPV, NPV and accuracy for diagnosis of colorectal endometriosis increased from 76%, 96%, 84%, 93% and 91%, to 95%, 97%, 91%, 99% and 97% for the most experienced radiologist and from 62%, 93%, 72%, 89% and 85%, to 86%, 94%, 82%, 96% and 92% for the less experienced radiologist; moreover, the interobserver agreement increased from 0.63 to 0.80 (Cohen's K test). CE-MR-C allows easier recognition of colorectal endometriosis and higher interobserver agreement. (orig.)

Diagnosis of colorectal endometriosis: contribution of contrast enhanced MR-colonography

Energy Technology Data Exchange (ETDEWEB)

Scardapane, Arnaldo; Lorusso, Filomenamila; Stabile Ianora, Amato Antonio; Lasciarrea, Maurilia; Angelelli, Giuseppe [University Hospital Policlinico, Department of Internal Medicine and Public Health (Di.M.I.M.P.) - Section of Diagnostic Imaging, Bari (Italy); Bettocchi, Stefano; Vimercati, Antonella; Ceci, Oronzo [University Hospital Policlinico, Department of General and Specialistic Surgical Sciences, Section of Obstetrics and Gynaecology, Bari (Italy)

2011-07-15

To investigate the contribution of contrast-enhanced MR-colonography (CE-MR-C) for the diagnosis of intestinal endometriosis. One hundred and four women with suspected endometriosis were prospectively enrolled. All patients were subjected to MRI consisting of two phases: pelvic high-resolution MRI (HR-MRI) followed by CE-MR-C after colonic distension using a 1.5-liter water enema and injection of 0.15 ml/kg of 0.5 M gadolinium-DTPA with T1w high-resolution isotropic volume (THRIVE) and balanced turbo field echo (BTFE) images. HR-MRI and CE-MR-C were considered as two datasets, which were independently reviewed by two radiologists with 12 and 2 years' experience respectively. The presence of deep pelvic endometriotic lesions with particular attention to colorectal involvement was recorded. MRI findings correlated with laparoscopy in all cases. Thanks to CE-MR-C images, sensitivity, specificity, PPV, NPV and accuracy for diagnosis of colorectal endometriosis increased from 76%, 96%, 84%, 93% and 91%, to 95%, 97%, 91%, 99% and 97% for the most experienced radiologist and from 62%, 93%, 72%, 89% and 85%, to 86%, 94%, 82%, 96% and 92% for the less experienced radiologist; moreover, the interobserver agreement increased from 0.63 to 0.80 (Cohen's K test). CE-MR-C allows easier recognition of colorectal endometriosis and higher interobserver agreement. (orig.)

Audit of the introduction of CT colonography for detection of colorectal carcinoma in a non-academic environment and its implications for the national bowel cancer screening programme

International Nuclear Information System (INIS)

Thomas, S.; Atchley, J.; Higginson, A.

2009-01-01

Aim: To compare the sensitivity of double-contrast barium enema (DCBE) with computed tomography colonography (CTC) to determine whether CTC is superior for the detection of colorectal cancer (CRC) locally, and to compare the results to those of a national barium enema audit. Materials and methods: All patients undergoing diagnostic DCBE or CTC between January 2003 and December 2005 were identified from the picture archiving communication system (PACS). Patients with a confirmed diagnosis of CRC were identified from the local cancer registry. Patients who were not diagnosed as having CRC on imaging were assumed true negatives if they were not listed in the cancer registry by December 2007, giving a minimum of 2 years follow-up. DCBE and CTC reports of all patients with CRC were analysed, and cancer detection was considered to have occurred (positive test result) if the report stated the definite presence of CRC or possible CRC requiring further investigation. Results: 2520 DCBEs and 604 CTCs were included. Twenty-one of 33 patients with CRC were detected using DCBE (incidence 1.31%, sensitivity 63.7%). Thirty-two of 33 patients with CRC were -detected using CTC (incidence 5.46%, sensitivity 97.7%). Conclusion: CTC is more sensitive for the detection of CRC, and its introduction in a district general hospital is justified. However, there has been a consequent decline in DCBE sensitivity, which, if reflected nationally, suggests CTC is the preferential screening test for CRC

Audit of the introduction of CT colonography for detection of colorectal carcinoma in a non-academic environment and its implications for the national bowel cancer screening programme

Energy Technology Data Exchange (ETDEWEB)

Thomas, S. [Department of Radiology, Queen Alexandra Hospital, Southwick Hill Road, Cosham, Portsmouth PO3 6AD (United Kingdom)], E-mail: Susan.Thomas@porthosp.nhs.uk; Atchley, J.; Higginson, A. [Department of Radiology, Queen Alexandra Hospital, Southwick Hill Road, Cosham, Portsmouth PO3 6AD (United Kingdom)

2009-02-15

Aim: To compare the sensitivity of double-contrast barium enema (DCBE) with computed tomography colonography (CTC) to determine whether CTC is superior for the detection of colorectal cancer (CRC) locally, and to compare the results to those of a national barium enema audit. Materials and methods: All patients undergoing diagnostic DCBE or CTC between January 2003 and December 2005 were identified from the picture archiving communication system (PACS). Patients with a confirmed diagnosis of CRC were identified from the local cancer registry. Patients who were not diagnosed as having CRC on imaging were assumed true negatives if they were not listed in the cancer registry by December 2007, giving a minimum of 2 years follow-up. DCBE and CTC reports of all patients with CRC were analysed, and cancer detection was considered to have occurred (positive test result) if the report stated the definite presence of CRC or possible CRC requiring further investigation. Results: 2520 DCBEs and 604 CTCs were included. Twenty-one of 33 patients with CRC were detected using DCBE (incidence 1.31%, sensitivity 63.7%). Thirty-two of 33 patients with CRC were -detected using CTC (incidence 5.46%, sensitivity 97.7%). Conclusion: CTC is more sensitive for the detection of CRC, and its introduction in a district general hospital is justified. However, there has been a consequent decline in DCBE sensitivity, which, if reflected nationally, suggests CTC is the preferential screening test for CRC.

CAD: How it works, how to use it, performance

International Nuclear Information System (INIS)

Regge, Daniele; Halligan, Steve

2013-01-01

Computer-aided diagnosis (CAD) systems are software algorithms designed to assist radiologists (or other practitioners) in solving a diagnostic problem by using a visual prompt (or “CAD mark”) to direct the observer towards potential pathology. CT colonography is a recent arrival to CAD, but could represent one of its most fruitful applications in the future. In contrast to other organs, where a variety of different pathologies are equally represented, significant colorectal pathologies other than polyps and cancer are relatively uncommon. As we shall see, this simplifies the diagnostic task for artificial intelligence developers and also for radiologists who, ultimately, must make the final decision. This review aims to present the current state-of-the-art for CAD applied to CT colonography. A brief overview of the technical essentials and of the diagnostic performance of CAD in isolation, is followed by an explanation of how CAD is used in day-to-day practice. The last section will deal with the most controversial issues affecting CAD performance in clinical practice, with a focus on the interaction between human and artificial intelligence

CAD: How it works, how to use it, performance

Energy Technology Data Exchange (ETDEWEB)

Regge, Daniele, E-mail: daniele.regge@ircc.it [Institute for Cancer Research and Treatment, Candiolo-Torino (Italy); Halligan, Steve, E-mail: s.halligan@ucl.ac.uk [University College Hospital London, London (United Kingdom)

2013-08-15

Computer-aided diagnosis (CAD) systems are software algorithms designed to assist radiologists (or other practitioners) in solving a diagnostic problem by using a visual prompt (or “CAD mark”) to direct the observer towards potential pathology. CT colonography is a recent arrival to CAD, but could represent one of its most fruitful applications in the future. In contrast to other organs, where a variety of different pathologies are equally represented, significant colorectal pathologies other than polyps and cancer are relatively uncommon. As we shall see, this simplifies the diagnostic task for artificial intelligence developers and also for radiologists who, ultimately, must make the final decision. This review aims to present the current state-of-the-art for CAD applied to CT colonography. A brief overview of the technical essentials and of the diagnostic performance of CAD in isolation, is followed by an explanation of how CAD is used in day-to-day practice. The last section will deal with the most controversial issues affecting CAD performance in clinical practice, with a focus on the interaction between human and artificial intelligence.

CT Colonography - competition or complementary?: guest editorial ...

African Journals Online (AJOL)

South African Gastroenterology Review. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 2, No 2 (2004) >. Log in or Register to get access to full text downloads.

CT Colonography - competition or complementary?: guest editorial ...

African Journals Online (AJOL)

South African Gastroenterology Review. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 2, No 2 (2004) >. Log in or Register to get access to full text downloads.

Transabdominal Ultrasound Colonography for Detection of Colorectal Neoplasms: Initial Clinical Experience.

Science.gov (United States)

Liu, Jin-Ya; Chen, Li-Da; Xu, Jian-Bo; Wu, Hui; Ye, Jin-Ning; Zhang, Xin-Hua; Xie, Xiao-Yan; Wang, Wei; Lu, Ming-De

2017-10-01

We investigated the feasibility of using ultrasound colonography (USC) to visualize the healthy colon and rectum and detect colorectal polyps. Eight healthy volunteers underwent USC after standard bowel preparation. The feasibility and image quality of USC in different segments were evaluated. Then, USC was conducted on eight patients with known colonic neoplasms using colonoscopy as the reference standard. For volunteers, USC examinations were successfully performed on four (50.0%) ascending, three (37.5%) transverse and eight (100%) descending colons, as well as all sigmoid colons and rectums. One of four (25.0%) ascending, two of eight (25.0%) descending and all sigmoid colons and rectums were well visualized and free of artifacts. For patients, colonoscopy revealed that eight patients had 17 neoplasms in the distal sigmoid colon and rectum, which included 3 lesions ≤5 mm, 3 lesions 6-9 mm and 11 lesions ≥10 mm. USC visualized 12 of 17 (70.6%) neoplasms. Lesion detection by USC was 0% (0/3), 33.3% (1/3) and 100% (11/11) for neoplasms ≤5, 6-9 mm and ≥10 mm in size. USC can visualize the sigmoid colon and rectum well and detect distal sigmoid and rectal neoplasms ≥10 mm in diameter. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Utility of dark-lumen MR colonography for the assessment of extra-colonic organs

International Nuclear Information System (INIS)

Ajaj, Waleed; Goyen, Mathias; Ruehm, Stefan G.; Ladd, Susanne C.; Gerken, Guido

2007-01-01

The aim of the study was to evaluate the utility of dark-lumen MR colonography (MRC) for the assessment of extra-colonic organs. Three hundred seventy-five subjects with suspected colonic disease underwent a complete MRC examination. MRC data were evaluated by two radiologists in a blinded fashion. In addition to the large bowel, the extra-intestinal organs from the lung bases to the pelvis were assessed for the presence of pathologies. All findings were divided into known or unknown findings and therapeutically relevant or irrelevant findings. If deemed necessary, other diagnostic imaging tests to further assess those findings were performed. In total, 510 extra-colonic findings were found in 260 (69%) of the 375 subjects. Known extra-colonic findings were found in 140 subjects (54%) and unknown findings in 120 subjects (46%). Thirty-one (12%) of the 260 subjects had therapeutically relevant findings (45 findings); 229 patients (88%) had irrelevant findings (465 findings). Dark-lumen MRC is a useful tool not only for the assessment of the entire colon, but also for the evaluation of extra-colonic organs. Thus, intra- and extra-colonic pathologies can be diagnosed within the same examination. (orig.)

Seeing is believing: video classification for computed tomographic colonography using multiple-instance learning.

Science.gov (United States)

Wang, Shijun; McKenna, Matthew T; Nguyen, Tan B; Burns, Joseph E; Petrick, Nicholas; Sahiner, Berkman; Summers, Ronald M

2012-05-01

In this paper, we present development and testing results for a novel colonic polyp classification method for use as part of a computed tomographic colonography (CTC) computer-aided detection (CAD) system. Inspired by the interpretative methodology of radiologists using 3-D fly-through mode in CTC reading, we have developed an algorithm which utilizes sequences of images (referred to here as videos) for classification of CAD marks. For each CAD mark, we created a video composed of a series of intraluminal, volume-rendered images visualizing the detection from multiple viewpoints. We then framed the video classification question as a multiple-instance learning (MIL) problem. Since a positive (negative) bag may contain negative (positive) instances, which in our case depends on the viewing angles and camera distance to the target, we developed a novel MIL paradigm to accommodate this class of problems. We solved the new MIL problem by maximizing a L2-norm soft margin using semidefinite programming, which can optimize relevant parameters automatically. We tested our method by analyzing a CTC data set obtained from 50 patients from three medical centers. Our proposed method showed significantly better performance compared with several traditional MIL methods.

Reduction in training time of a deep learning model in detection of lesions in CT

Science.gov (United States)

Makkinejad, Nazanin; Tajbakhsh, Nima; Zarshenas, Amin; Khokhar, Ashfaq; Suzuki, Kenji

2018-02-01

Deep learning (DL) emerged as a powerful tool for object detection and classification in medical images. Building a well-performing DL model, however, requires a huge number of images for training, and it takes days to train a DL model even on a cutting edge high-performance computing platform. This study is aimed at developing a method for selecting a "small" number of representative samples from a large collection of training samples to train a DL model for the could be used to detect polyps in CT colonography (CTC), without compromising the classification performance. Our proposed method for representative sample selection (RSS) consists of a K-means clustering algorithm. For the performance evaluation, we applied the proposed method to select samples for the training of a massive training artificial neural network based DL model, to be used for the classification of polyps and non-polyps in CTC. Our results show that the proposed method reduce the training time by a factor of 15, while maintaining the classification performance equivalent to the model trained using the full training set. We compare the performance using area under the receiveroperating- characteristic curve (AUC).

Computer-aided detection of colorectal polyps: can it improve sensitivity of less-experienced readers? Preliminary findings.

Science.gov (United States)

Baker, Mark E; Bogoni, Luca; Obuchowski, Nancy A; Dass, Chandra; Kendzierski, Renee M; Remer, Erick M; Einstein, David M; Cathier, Pascal; Jerebko, Anna; Lakare, Sarang; Blum, Andrew; Caroline, Dina F; Macari, Michael

2007-10-01

To determine whether computer-aided detection (CAD) applied to computed tomographic (CT) colonography can help improve sensitivity of polyp detection by less-experienced radiologist readers, with colonoscopy or consensus used as the reference standard. The release of the CT colonographic studies was approved by the individual institutional review boards of each institution. Institutions from the United States were HIPAA compliant. Written informed consent was waived at all institutions. The CT colonographic studies in 30 patients from six institutions were collected; 24 images depicted at least one confirmed polyp 6 mm or larger (39 total polyps) and six depicted no polyps. By using an investigational software package, seven less-experienced readers from two institutions evaluated the CT colonographic images and marked or scored polyps by using a five-point scale before and after CAD. The time needed to interpret the CT colonographic findings without CAD and then to re-evaluate them with CAD was recorded. For each reader, the McNemar test, adjusted for clustered data, was used to compare sensitivities for readers without and with CAD; a Wilcoxon signed-rank test was used to analyze the number of false-positive results per patient. The average sensitivity of the seven readers for polyp detection was significantly improved with CAD-from 0.810 to 0.908 (P=.0152). The number of false-positive results per patient without and with CAD increased from 0.70 to 0.96 (95% confidence interval for the increase: -0.39, 0.91). The mean total time for the readings was 17 minutes 54 seconds; for interpretation of CT colonographic findings alone, the mean time was 14 minutes 16 seconds; and for review of CAD findings, the mean time was 3 minutes 38 seconds. Results of this feasibility study suggest that CAD for CT colonography significantly improves per-polyp detection for less-experienced readers. Copyright (c) RSNA, 2007.

STUDY ON VIRTUAL COLONOSCOPY

Directory of Open Access Journals (Sweden)

Aithagani Rama Chandraiah

2016-10-01

Full Text Available BACKGROUND Current options available in the investigations of colorectal carcinoma include screening using digital rectal examination, sigmoidoscopy, barium enema and fiberoptic colonoscopy, virtual colonoscopy. The aim of the study was to prospectively evaluate patient acceptance of virtual colonoscopy compared with that of conventional colonoscopy when performed in patients with or suspected of having colorectal disease. MATERIALS AND METHODS The study had been conducted on patients attending Department of Radiology for a period of 1 year. Patients with primary or secondary complaints of pain abdomen, lump in abdomen, bleeding per rectum, loose motions/constipation, altered bowel habits, loss of appetite and weight and anaemia, so total number of cases were 51. RESULTS In our study, the patients were in age groups of 21-70 years. Both sexes were represented in our study. Male preponderance was noted in 51 patients. Cases of adenoma were more commonly found 37 (72.78%. The sensitivity of the CT colonography for the polyps more than 10 mm is 100%, polyps 6-9 mm is 90%, less than 6 mm is 80%. Our study consists of 51 patients; among them, 30 patients showed acceptance for CT colonography, 10 patients for optical colonoscopy. Our study consists of 51 patients, the polyps (more than 10 mm detected in 2D viewing were 24, 2D and 3D viewing of 24, the polyps (less than 10 mm detected in 2D viewing were 15, 2D and 3D viewing were 17. 3D viewing resulted in increased sensitivity for identification of patients with larger polyps more than 1 cm, (70-85% sensitivity and patients with smaller polyps less than 1 cm (increased sensitivity 75-88%. CONCLUSIONS Multislice CT (64 colonography is a good alternative to other colorectal screening tests because it has high sensitivity for polyps 10 mm or more in diameter is relatively safe, clinical effective, minimally invasive, cost effective and filter for therapeutic optical colonoscopy.

Cost-Effectiveness of Computed Tomographic Colonography: A Prospective Comparison with Colonoscopy

International Nuclear Information System (INIS)

Arnesen, R.B.; Ginnerup-Pedersen, B.; Poulsen, P.B.; Benzon, K. von; Adamsen, S.; Laurberg, S.; Hart-Hansen, O.

2007-01-01

Purpose: To estimate the cost-effectiveness of detecting colorectal polyps with computed tomographic colonography (CTC) and subsequent polypectomy with primary colonoscopy (CC), using CC as the alternative strategy. Material and Methods: A marginal analysis was performed regarding 103 patients who had had CTC prior to same-day CC at two hospitals, H-I (n 53) and H-II (n = 50). The patients were randomly chosen from surveillance and symptomatic study populations (148 at H-I and 231 at H-II). Populations, organizations, and procedures were compared. Cost data on time consumption, medication, and minor equipment were collected prospectively, while data on salaries and major equipment were collected retrospectively. The effect was the (previously published) sensitivities of CTC and CC for detection of colorectal polyps ≥6 mm (H-I, n = 148) or ≥5 mm (H-II, n = 231). Results: Thirteen patients at each center had at least one colorectal polyp ≥6 mm or ≥5 mm. CTC was the cost-effective alternative at H-I (Euro 187 vs. Euro 211), while CC was the cost-effective alternative at H-II (Euro 239 vs. Euro 192). The cost-effectiveness (costs per finding) mainly depended on the sensitivity of CTC and CC, but the depreciation of equipment and the staff's use of time were highly influential as well. Conclusion: Detection of colorectal polyps ≥6 mm or ≥5 mm with CTC, followed by polypectomy by CC, can be performed cost-effectively at some institutions with the appropriate hardware and organization keywords

Acceptability of oral iodinated contrast media: a head-to-head comparison of four media

Science.gov (United States)

Ngan-Soo, E; McCoubrie, P

2013-01-01

Objective: To assess the palatability of iodinated oral contrast media commonly used in abdominopelvic CT and CT colonography (CTC). Methods: 80 volunteers assessed the palatability of a 20-ml sample of a standard 30 mg ml−1 dilution of Omnipaque® (iohexol; GE Healthcare, Cork, Ireland), Telebrix® (meglumine ioxithalamate; Guerbet, Aulnay-sous-Bois, France), Gastromiro® (iopamidol; Bracco, High Wycombe, UK) and Gastrografin® (sodium diatrizoate and meglumine diatrizoate; Bayer, Newbury, UK) in a computer-generated random order. Results: Gastrografin is rated significantly less palatable than the remaining media (pcontrast media than both Gastromiro and Gastrografin, which has potential implications in compliance with both abdominopelvic CT and CTC. PMID:23564884

Dark-lumen magnetic resonance colonography in patients with suspected sigmoid diverticulitis: a feasibility study

International Nuclear Information System (INIS)

Ajaj, Waleed; Lauenstein, Thomas; Goehde, Susanne; Kuehle, Christiane; Herborn, Christoph U.; Ruehm, Stefan G.; Langhorst, Jost; Zoepf, Thomas; Gerken, Guido; Goyen, Mathias

2005-01-01

To assess dark-lumen magnetic resonance colonography (MRC) for the evaluation of patients with suspected sigmoid diverticulitis. Forty patients with suspected sigmoid diverticulitis underwent MRC within 72 h prior to conventional colonoscopy (CC). A three-dimensional T1-weighted volumetric interpolated breath-hold examination sequence was acquired after an aqueous enema and intravenous administration of gadolinium-based contrast agents. All MRC data were evaluated by two radiologists. Based on wall thickness and focal uptake of contrast material and pericolic reaction including mesenteric infiltration on T1-weighted sequence the sigmoid colon was assessed for the presence of diverticulitis. MRC classified 17 of the 40 patients as normal with regard to sigmoid diverticulitis. However, CC confirmed the presence of light inflammatory signs in four patients which were missed in MRC. MRC correctly identified wall thickness and contrast uptake of the sigmoid colon in the other 23 patients. In three of these patients false-positive findings were observed, and MRC classified the inflammation of the sigmoid colon as diverticulitis whereas CC and histopathology confirmed invasive carcinoma. MRC detected additionally relevant pathologies of the entire colon and could be performed in cases where CC was incomplete. MRC may be considered a promising alternative to CC for the detection of sigmoid diverticulitis. (orig.)

Magnetic Resonance Colonography May Predict the Need for Bowel Resection in Colorectal Endometriosis

Directory of Open Access Journals (Sweden)

Arnaldo Scardapane

2017-01-01

Full Text Available Purpose. To define if MRI findings in patients with deep pelvic endometriosis (DPE may be predictive for the need of bowel resection. Material and Methods. A retrospective survey of 196 pelvic MRIs of women who received laparoscopic procedures for DPE was carried out. A pelvic MRI was performed in all patients: it consisted in T2w-TSE sequences in axial, sagittal, and coronal planes and T1w and THRIVE sequences in the axial plane; the exam was completed by MR-Colonography. Intestinal lesions were measured in short and long axis and the degree of stenosis was established. A multivariate logistic regression was used to identify the predictors of intestinal resection. Results. 57/196 patients received an intestinal resection. Multivariate logistic regression demonstrated a predictive value of short axis (Odds-Ratio = 2.29, p=0.011 and stenosis (Odds-Ratio = 1.20, p=0.003. ROC analysis showed that a cut-off value of 11 mm for the short axis and 30% for the stenosis may correctly classify, respectively, 96,94% (sensitivity 92,9% and specificity 98,56% and 97,96% (sensitivity 94,74% and specificity 99,3% of the cases. Conclusion. The presence of an endometriotic rectal nodule > 11 mm in short axis causing a stenosis > 30% in pelvic MRI reliably predicts the need of a rectal resection.

Dolichocolon revisited

DEFF Research Database (Denmark)

Raahave, Dennis

2018-01-01

The objective of this review is to examine whether a redundant colon gives rise to symptoms like constipation and volvulus. In 1820, Monterossi made drawings of colons with displacements and elongation of the colon found during autopsy. In 1912, Kienböeck first visualized a redundant colon using...... and infrequent defecation. The diagnosis of dolichocolon is established by barium enema or CT-colonography. Treatment is conservative, or surgical in case of volvulus or refractory constipation....

Prevalence and clinical significance of extravascular incidental findings in patients undergoing CT cervico-cerebral angiography

International Nuclear Information System (INIS)

Crockett, Matthew Thomas; Murphy, Blathnaid; Smith, Jennifer; Kavanagh, Eoin Carl

2015-01-01

Highlights: • CT cervico-cerebral angiography (CTCCA) is a commonly performed study for assessment of vascular pathologies of head and neck. • This study assessed the prevalence, clinical significance and management of extravascular incidental findings detected on CTCCA. • This study demonstrated the presence of clinically significant incidental findings in 14% of patients undergoing CTCCA with 8% of these findings deemed to be highly significant. 19% of patients with highly clinically significant findings did not receive appropriate follow up. • A standardised method of reporting incidental findings, such as that used in this paper is suggested to aid radiologists and referring physicians in recording and communicating these findings. - Abstract: Introduction: CT cervico-cerebral angiography (CTCCA) is now the first line diagnostic imaging modality for the majority of vascular pathologies of the head and neck with diagnostic value comparable to or better than traditional angiographic techniques. The aim of this study was to assess the prevalence, clinical significance and management of extravascular incidental findings detected on CTCCA. Materials and methods: A retrospective review of the CTCCA reports of 302 consecutive patients from 2009 to 2013 was undertaken. Extravascular incidental findings were classified, according to an adaptation of the CT colonography data and reporting system (CRADS), as EV1–EV4. EV1 = no incidental findings, EV2 = clinically insignificant incidental finding, EV3 = incidental finding of intermediate clinical significance, EV4 = highly clinically significant finding. Follow up of the electronic medical records of patients with EV3 or EV4 findings was undertaken to determine subsequent management. Results: Potentially clinically significant findings were demonstrated in 14.2% of patients with 8.6% of patients having a highly clinically significant finding. 4 incidental findings were confirmed to be malignant lesions and 5

Comparison of CT numbers between cone-beam CT and multi-detector CT

International Nuclear Information System (INIS)

Kim, Dong Soo; Han, Won Jeong; Kim, Eun Kyung

2010-01-01

To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, ρ(g/cm 3 ), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were ρ=0.001 H+1.07 with R2 value of 0.999 for Somatom Emotion, ρ=0.002 H+1.09 with R2 value of 0.991 for Alphard VEGA, ρ=0.001 H+1.43 with R2 value of 0.980 for i-CAT and ρ=0.001 H+1.30 with R2 value of 0.975 for Implagraphy. CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

Comparison of CT numbers between cone-beam CT and multi-detector CT

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Soo; Han, Won Jeong; Kim, Eun Kyung [Department of Oral and Maxillofacial Radiology, School of Dentistry, Dankook University, Cheonan (Korea, Republic of)

2010-06-15

To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, {rho}(g/cm{sup 3}), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were {rho}=0.001 H+1.07 with R2 value of 0.999 for Somatom Emotion, {rho}=0.002 H+1.09 with R2 value of 0.991 for Alphard VEGA, {rho}=0.001 H+1.43 with R2 value of 0.980 for i-CAT and {rho}=0.001 H+1.30 with R2 value of 0.975 for Implagraphy. CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

Computer-aided detection in computed tomography colonography. Current status and problems with detection of early colorectal cancer

International Nuclear Information System (INIS)

Morimoto, Tsuyoshi; Nakijima, Yasuo; Iinuma, Gen; Arai, Yasuaki; Shiraishi, Junji; Moriyama, Noriyuki; Beddoe, G.

2008-01-01

The aim of this study was to evaluate the usefulness of computer-aided detection (CAD) in diagnosing early colorectal cancer using computed tomography colonography (CTC). A total of 30 CTC data sets for 30 early colorectal cancers in 30 patients were retrospectively reviewed by three radiologists. After primary evaluation, a second reading was performed using CAD findings. The readers evaluated each colorectal segment for the presence or absence of colorectal cancer using five confidence rating levels. To compare the assessment results, the sensitivity and specificity with and without CAD were calculated on the basis of the confidence rating, and differences in these variables were analyzed by receiver operating characteristic (ROC) analysis. The average sensitivities for the detection without and with CAD for the three readers were 81.6% and 75.6%, respectively. Among the three readers, only one reader improved sensitivity with CAD compared to that without. CAD decreased specificity in all three readers. CAD detected 100% of protruding lesions but only 69.2% of flat lesions. On ROC analysis, the diagnostic performance of all three readers was decreased by use of CAD. Currently available CAD with CTC does not improve diagnostic performance for detecting early colorectal cancer. An improved CAD algorithm is required for detecting fiat lesions and reducing the false-positive rate. (author)

Diagnostic accuracy of radiographer reporting of computed tomography colonography examinations: A systematic review

International Nuclear Information System (INIS)

Meertens, R.; Brealey, S.; Nightingale, J.; McCoubrie, P.

2013-01-01

Computed tomography colonography (CTC) is the primary radiological test for the detection of colorectal tumours and precancerous polyps. Radiographer reporting of CTC examinations could help to improve the provision of this expanding service. We undertook a systematic review to assess the accuracy with which radiographers can provide formal written reports on intraluminal disease entities of CTC examinations compared to a reference standard. Data sources searched included online databases, peer-reviewed journals, grey literature, and reference and citation tracking. Eligible studies were assessed for bias, and data were extracted on study characteristics. Pooled estimates of sensitivities and specificities and chi-square tests of heterogeneity were calculated. Eight studies were eligible for inclusion with some risk to bias. Pooled estimates from three studies showed per patient sensitivity and specificity of reporting radiographers was 76% (95% CI: 70–80%) and 74% (95% CI: (67–80%), respectively. From seven studies, per lesion sensitivity for the detection of lesions >5 and >10 mm was 68% (95% CI: 65–71%) and 75% (95% CI: 72–79%) respectively. Pooled sensitivity for detection of lesions >5 mm in studies for which radiographers reported 50 or less training cases was 57% (95% CI: 52–61%) and more than 50 cases was 78% (95% CI: 74–81%). The current evidence does not support radiographers in a role involving the single formal written reporting of CTC examinations. Radiographers' performance, however, did appear to improve significantly with the number read. Therefore, when provided with adequate training and experience, there may be a potential role for radiographers in the reporting of CTC examinations

Clinical Application of colored three-dimensional CT (3D-CT) for brain tumors using helical scanning CT (HES-CT)

International Nuclear Information System (INIS)

Ogura, Yuko; Katada, Kazuhiro; Fujisawa, Kazuhisa; Imai, Fumihiro; Kawase, Tsukasa; Kamei, Yoshifumi; Kanno, Tetsuo; Takeshita, Gen; Koga, Sukehiko

1995-01-01

We applied colored three-dimensional CT (colored 3D-CT) images to distinguish brain tumors from the surrounding vascular and bony structures using a work station system and helical scanning CT (HES-CT). CT scanners with a slip-ring system were employed (TCT-900S and X vigor). A slice thickness of 2 mm and bed speed of 2 mm/s were used. The volume of contrast medium injected was 60 to 70 ml. Four to 8 colors were used for the tissue segmentation on the workstation system (xtension) using the data transferred from HES-CT. Tissue segmentation succeeded on the colored 3D-CT images in all 13 cases. The relationship between the tumors and the surrounding structures were easily recognized. The technique was useful to simulate operative fields, because deep structures could be visualized by cutting and drilling the colored 3D-CT volumetric data. On the basis of our findings, we suggest that colored 3D-CT images should be used as a supplementary aid for preoperative simulation. (author)

Ultra-low dose CT attenuation correction for PET/CT

International Nuclear Information System (INIS)

Xia Ting; Kinahan, Paul E; Alessio, Adam M; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren

2012-01-01

A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. (paper)

Ultra-low dose CT attenuation correction for PET/CT

Science.gov (United States)

Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

2012-01-01

A challenge for PET/CT quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently-available, lowest dose CT techniques, extended duration CINE CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. Methods We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. Results CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. Conclusion When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. PMID:22156174

Clinical application of gated CT and dynamic CT

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, T; Oyama, Y; Ashida, H; Uji, T [Saint Marianna Univ., Kawasaki, Kanagawa (Japan). School of Medicine

1980-03-01

Gated CT and dynamic CT were outlined. Experiences of portal hypertension accompanied by venous mass in posterior mediastinum and the usefulness of dynamic CT for this disease were described. Gated CT of the heart could visualize intracardiac structures and morphological abnormalities by improving technique of post-data-aquisition correlation. Changes with time in CT images of normal kidneys were discussed on patients whose unilateral or bilateral kidneys were thought to be normal and who had received dynamic scan. Dynamic scan could visualize well blood circulation and mechanism of urine excretion in the kidney, which suggests a possibility of CT to detect not only morphological abnormalities but also functional disturbance of the kidney. The effectiveness of conventional CT study might be promoted in dynamic CT of the head.

Technical quality of CT colonography in relation with diverticular disease

International Nuclear Information System (INIS)

Flor, Nicola; Rigamonti, Paolo; Di Leo, Giovanni; Ceretti, Andrea Pisani; Opocher, Enrico; Sardanelli, Francesco; Cornalba, Gian Paolo

2012-01-01

Objective: The aim of the study is to explore how the technical quality of the examination was affected by diverticular disease. Materials and methods: We retrospectively evaluated a consecutive series of 78 subjects who underwent CTC for screening (n = 58) or staging (n = 20) colorectal cancer, 38 of them (49%) after an incomplete optical colonoscopy. Patients were administered a mild laxative and a iodinated contrast material for fecal tagging. We scored both the bowel preparation and the overall colon distension as poor, good, or optimal and measured the mean sigmoid colon diameter. We counted the number of diverticula and classified patients as having or not a severe diverticular disease (SDD). The number of the prompts of computer aided diagnosis (CAD) per patient was also considered. Mann–Whitney U and χ 2 tests were performed. Results: No CTC complications occurred. The bowel cleansing was poor in 8 (10%) patients, good in 29 (37%) and optimal in 41 (53%); colon distension was poor in 7 (9%) patients, good in 38 (49%), and optimal in 33 (42%). Fifty-four (69%) showed diverticula and 30 (38%) had an SDD. Bowel cleansing and distension were not significantly impaired by neither diverticula (p > 0.590) nor the SDD (p > 0.110). Mean sigmoid colon diameter was reduced in presence of diverticula (28 mm versus 23 mm, p = 0.009) or SDD (26 mm versus 22 mm, p = 0.016). The mean number of CAD prompts per patient was not significantly increased by the presence of SDD (p = 0.829). Conclusions: Bowel cleansing and distension at CTC were not influenced by the presence of diverticular disease.

Potential pitfalls in the anorectal region during CT colonography: A ...

African Journals Online (AJOL)

2017-02-28

Feb 28, 2017 ... smart phone or ... require further investigation and may require just a digital rectal ... pathology-related pitfalls (internal haemorrhoids, polyps, cancer, ... interpretation problems.12 It is preferable to use a small gauge (25 Fr.

Colonic dysmotility and morphological abnormality frequently detected in Japanese patients with irritable bowel syndrome

Directory of Open Access Journals (Sweden)

Takeshi Mizukami

2017-04-01

Full Text Available Background/Aims: Colonoscopy and computed tomography (CT are used primarily to exclude organic diseases in patients with irritable bowel syndrome (IBS, rather than to assess the pathophysiology of IBS. We aimed to evaluate colonic dysmotility and morphology in Japanese patients with IBS.Methods: One hundred eighty-four patients with IBS and 49 asymptomatic controls who underwent colonoscopy in combination with CT colonography or barium enema were retrospectively reviewed between 2008 and 2012. Water-aided colonoscopy was performed without sedation by a single endoscopist. The duration and pattern of colonic movement and cecal intubation time were recorded. To assess colonic morphology, barium enema or CT colonography were performed immediately after colonoscopy.Results: Colonic dysmotility was more frequent in the IBS group (28.8% vs. 2.0% in controls, P<0.001, especially in cases of IBS with diarrhea (IBS-D (IBS with constipation [IBS-C] 28.8% vs. IBS-D 60.0% vs. mixed IBS [IBS-M] 5.1%, P<0.001. Colonic morphological abnormality was more frequent in the IBS group than in the control group (77.7% vs. 24.5%, P<0.001, especially in IBS-M and IBS-C groups (IBS-C 77.5% vs. IBS-D 48.9% vs. IBS-M 100%, P<0.001. Most patients with IBS with colonic dysmotility had experienced stress related to their symptoms. Cecal intubation time was significantly longer in the IBS group than in the control group (12.1±6.9 minutes vs. 4.6±1.9 minutes, P<0.001.Conclusions: Unsedated colonoscopy, combined with radiographic findings, can detect colonic dysmotility and morphological abnormality. Technical difficulties observed during cecal intubation may partially explain the pathophysiology of IBS.

PET/CT in lymphoma patients; PET-CT bei Lymphompatienten

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Steinert, H.C. [Universitaetsspital Zuerich, Klinik und Poliklinik fuer Nuklearmedizin (Switzerland)

2004-11-01

First results of PET/CT in Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) are reported. From March 2001 to August 2004 822 PET/CT were performed at our clinic in lymphoma patients for primary staging, restaging after therapy, and diagnosis of recurrence. For coregistration non contrast-enhanced low-dose CT were used. Due to the exact anatomic localization of {sup 18}F-FDG accumulating lesions equivocal or false positive PET findings are avoided. In comparison to contrast enhanced CT, PET/CT has a higher sensitivity and specificity in patients with HD and aggressive NHL. Integration of PET/CT in treatment planning of radiation therapy optimizes the field volume. Even in the initial phase of clinical evaluation, PET/CT has proven useful in staging and restaging of lymphoma. The exact anatomic localization of the PET findings is essential for a precise report, for treatment planning of radiation therapy, and for planning surgical biopsy. (orig.) [German] Erste Ergebnisse der PET-CT bei Morbus Hodgkin (HD) und den aggressiven Non-Hodgkin-Lymphomen (NHL) werden beschrieben. Von Maerz 2001 bis August 2004 wurden 822 PET-CT bei Lymphompatienten zum primaeren Staging, zum Restaging nach Therapie und zur Rezidivdiagnostik an unserer Klinik durchgefuehrt. Fuer die Koregistration wurde ein Low-dose-CT ohne i.v.-Kontrastmittel verwendet. Durch die exakte anatomische Zuordnung der {sup 18}F-FDG aufnehmenden Laesionen wurden unklare oder falsch-positive PET-Befunde vermieden. Die PET-CT erzielte im Vergleich zur KM-verstaerkten CT eine hoehere Sensitivitaet und Spezifitaet bei Patienten mit HD und aggressiven NHL. Die Integration der PET-CT in die Planung der Strahlentherapie fuehrte zu einer Optimierung der Feldgrenzen. Die PET-CT hat sich bereits in der Phase der initialen klinischen Evaluation als wertvoll beim Staging und Restaging von Lymphomen erwiesen. Die exakte anatomische Zuordnung der PET-Informationen ist fuer eine sichere Befundung

CT of hepatocellular carcinoma. Analysis of contrast-enhanced CT using CT arteriography

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Nakamura, H; Tanaka, T; Hori, S; Tokunaga, K; Yoshioka, H [Osaka Univ. (Japan). Faculty of Medicine

1981-02-01

Although changes in the CT appearance resulting from contrast enhancement (CE) for hepatocellular carcinoma have been considered in association with vascularity of tumors, no detailed studies have yet been made. We analyzed changes in the CT appearance following CE by comparing with hepatic arteriogram and CT arteriogram (CTA) performed during intraarterial infusion of contrast medium. When tumors showing low density in the plain CT were enhanced by contrast, the results were variable, ranging from intensification of the low density to replacement by high density, and the results were classified into L/sub 0/ to L/sub 3/ according to vascularity of tumors. The results after CE could also be classified into I/sub 0/ to I/sub 3/ when tumors showed isodensity in the plain CT. There was a correlation between vascularity presumed from CE and vascularity by CTA. It may be concluded that tumor vascularity could be estimated by the findings of CE which might indicate a possibility of qualitative diagnosis of tumors.

Incidental extracolonic findings on bright lumen MR colonography in a population at increased risk for colorectal carcinoma

International Nuclear Information System (INIS)

Yusuf, Erlangga; Florie, Jasper; Nio, Chung Yung; Jensch, Sebastian; Nievelstein, Rutger A.J.; Baak, Lubbertus; Stoker, Jaap

2011-01-01

Purpose: Incidental extracolonic findings affect patient treatment and cost. Therefore, to consider magnetic resonance colonography (MRC) as a tool for colorectal cancer and polyps screening, more knowledge is needed on extracolonic findings. In this study, we sought to determine the prevalence and the spectrum of extracolonic findings in patients with an increased risk colorectal cancer that underwent bright lumen MRC. Materials and methods: MRC examinations were performed in 210 patients. A gadolinium solution was administered rectally for distension of the colon. Extracolonic findings were scored by two radiologists and classified by using C-RADS Reporting System. All findings (with advice regarding work-up) were reported to the patient's physician and followed up for 4.5 years on average. Results: Extracolonic findings were found in 125 (59.5%) patients. Ten (4.8%) had 'potentially important' findings (C-RADS category E4). Twenty-five patients (11.9%) had 'likely unimportant' findings (E3), 90 (42.8%) had 'clinically unimportant' findings (E2) and 85 (40.5%) had a normal exam (E1). In 14 (6.7%) patients additional work-up was performed for their incidentally discovered lesions. In three of them surgery was performed. After work-up, only in two (1.0%) patients a malignancy was found. Conclusion: The number of new relevant extracolonic findings is small and the required additional work-up is limited. This should be considered for implementation of 'bright lumen' MRC as a screening tool.

Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: Impact on colorectal polyp detection.

LENUS (Irish Health Repository)

Keeling, Aoife N

2012-02-01

PURPOSE: To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC). MATERIALS AND METHODS: IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC. RESULTS: Twenty-four polyps were detected in eighteen patients with CC (5 polyps >\\/=10mm, 4 polyps 6-9mm, 15 polyps <\\/=5mm). MRC was 66.7% (12\\/18) sensitive and 96.4% (27\\/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5\\/5) and 100% (19\\/19), respectively, for lesions greater than 10mm, 100% (4\\/4) and 100% (20\\/20) for lesions 6-9mm, and sensitivity of 20% (3\\/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9\\/9) and 100% (15\\/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC. CONCLUSION: MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps >\\/=6mm in size. Further studies are warranted.

Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: Impact on colorectal polyp detection.

LENUS (Irish Health Repository)

Keeling, Aoife N

2010-12-03

PURPOSE: To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC). MATERIALS AND METHODS: IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC. RESULTS: Twenty-four polyps were detected in eighteen patients with CC (5 polyps ≥10mm, 4 polyps 6-9mm, 15 polyps ≤5mm). MRC was 66.7% (12\\/18) sensitive and 96.4% (27\\/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5\\/5) and 100% (19\\/19), respectively, for lesions greater than 10mm, 100% (4\\/4) and 100% (20\\/20) for lesions 6-9mm, and sensitivity of 20% (3\\/15) lesions less than 5mm. The sensitivity and specificity of MRC for detecting significant lesions (>6mm) was 100% (9\\/9) and 100% (15\\/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n=16) of patients preferred MRC as a future screening test compared to 33% (n=15) for CC. CONCLUSION: MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps ≥6mm in size. Further studies are warranted.

Absorbed dose in CT. Comparison by CT dose index

International Nuclear Information System (INIS)

Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

2002-01-01

Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

Imaging of head and neck tumors -- methods: CT, spiral-CT, multislice-spiral-CT

International Nuclear Information System (INIS)

Baum, Ulrich; Greess, Holger; Lell, Michael; Noemayr, Anton; Lenz, Martin

2000-01-01

Spiral-CT is standard for imaging neck tumors. In correspondence with other groups we routinely use spiral-CT with thin slices (3 mm), a pitch of 1.3-1.5 and an overlapping reconstruction increment (2-3 mm). In patients with dental fillings a short additional spiral parallel to the corpus of the mandible reduces artifacts behind the dental arches and improves the diagnostic value of CT. For the assessment of the base of the skull, the orbital floor, the palate and paranasal sinuses an additional examination in the coronal plane is helpful. Secondary coronal reconstructions of axial scans are helpful in the evaluation of the crossing of the midline by small tumors of the tongue base or palate. For an optimal vascular or tissue contrast a sufficient volume of contrast medium and a start delay greater than 70-80 s are necessary. In our opinion the best results can be achieved with a volume of 150 ml, a flow of 2.5 ml/s and a start delay of 80 s. Dynamic enhanced CT is only necessary in some special cases. There is clear indication for dynamic enhanced CT where a glomus tumor is suspected. Additional functional CT imaging during i-phonation and/or Valsalva's maneuver are of great importance to prove vocal cords mobility. Therefore, imaging during i-phonation is an elemental part of every thorough examination of the hypopharynx and larynx region. Multislice-spiral-CT allows almost isotropic imaging of the head and neck region and improves the assessment of tumor spread and lymph node metastases in arbitrary oblique planes. Thin structures (the base of the skull, the orbital floor, the hard palate) as well as the floor of the mouth can be evaluated sufficiently with multiplanar reformations. Usually, additional coronal scanning is not necessary with multislice-spiral-CT. Multislice-spiral-CT is especially advantageous in defining the critical relationships of tumor and lymph node metastases and for functional imaging of the hypopharynx and larynx not only in the

CT of portal vein tumor thrombosis. Usefulness of dynamic CT

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Takemoto, Kazumasa; Inoue, Yuichi; Tanaka, Masahiro; Nemoto, Yutaka; Nakamura, Kenji [Osaka City Univ. (Japan). Faculty of Medicine

1983-08-01

We evaluated CT findings of portal vein tumor thrombosis in 16 hepatomas by plain, contrast and dynamic CT. Plain and contrast CT findings were an enlargement of the portal vein (81%), intraluminal low density area (63%). Dynamic CT enhanced the diagnostic capability of the tumor thrombus as a relatively low density area because of the marked enhancement of the portal vein. In addition, dynamic CT newly demonstrated hyperdense peripheral ring (35%) and arterio portal shunt (35%). It is advisable to select the scan level to include the portal vein when dynamic CT is performed in the patient of hepatocellular carcinoma.

CT findings of pancreatic carcinoma. Evaluation with the combined method of early enhancement CT and high dose enhancement CT

International Nuclear Information System (INIS)

Itoh, Shigeki; Endo, Tokiko; Isomura, Takayuki; Ishigaki, Takeo; Ikeda, Mitsuru; Senda, Kouhei.

1995-01-01

Computed tomographic (CT) findings of pancreatic ductal adenocarcinoma were studied with the combined method of early enhancement CT and high dose enhancement CT in 72 carcinomas. Common Findings were change in pancreatic contour, abnormal attenuation in a tumor and dilatation of the main pancreatic duct. The incidence of abnormal attenuation and dilatation of the main pancreatic duct and bile duct was constant regardless of tumor size. The finding of hypoattenuation at early enhancement CT was most useful for demonstrating a carcinoma. However, this finding was negative in ten cases, five of which showed inhomogenous hyperattenuation at high dose enhancement CT. The detection of change in pancreatic contour and dilatation of the main pancreatic duct was most frequent at high dose enhancement CT. The finding of change in pancreatic contour and/or abnormal attenuation in a tumor could be detected in 47 cases at plain CT, 66 at early enhancement CT and 65 at high dose enhancement CT. Since the four cases in which neither finding was detected by any CT method showed dilatated main pancreatic duct, there was no case without abnormal CT findings. This combined CT method will be a reliable diagnostic technique in the imaging of pancreatic carcinoma. (author)

CT in neuromuscular disorders: A comparison of CT and histology

International Nuclear Information System (INIS)

Vliet, A.M. van der; Thijssen, H.O.M.; Merx, J.L.; Joosten, E.

1988-01-01

The value of CT-examination of the muscles compared to histology was studied in a retrospective analysis of 30 patients with clinical suspicion of neuromuscular disorder. In the evaluation of the CT-results descriptive criteria were used. The histologic diagnosis came from needle-biopsies taken from the quadriceps muscle. Considering the whole group of neuromuscular disorders, CT has an overall accuracy of 84.8%, a positive predictive value of 95.5% and a negative predictive value of 63.6%. This makes the use of CT as a diagnostic tool in neuromuscular disorders a reliable examination technique. In patients with a polymyositis there is even a 100% correlation between CT findings and biopsy results. Discrepancy between the biopsy results is remarkable of the quadriceps muscle and the CT findings: The number of abnormal histological findings is twice the number of abnormal CT findings. Using the more proximal gluteal region as a biopsy site would have decreased this discrepancy and would therefore have given a better correlation between CT and histology. The choice of protocol in determining the levels to be scanned is of great importance in achieving good reproducability in follow-up CT examinations. (orig.)

Combined SPECT/CT and PET/CT for breast imaging

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Russo, Paolo [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy); Larobina, Michele [Istituto di Biostrutture e Bioimmagini, Consiglio Nazionale delle Ricerche, Via Tommaso De Amicis, 95, Naples I-80145 (Italy); Di Lillo, Francesca [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy); Del Vecchio, Silvana [Università di Napoli Federico II, Dipartimento di Scienze Biomediche Avanzate, Via Pansini, 5, Naples I-80131 (Italy); Mettivier, Giovanni, E-mail: mettivier@na.infn.it [Università di Napoli Federico II, Dipartimento di Fisica, Via Cintia, Naples I-80126 (Italy); INFN Sezione di Napoli, Via Cintia, Naples I-80126 (Italy)

2016-02-11

In the field of nuclear medicine imaging, breast imaging for cancer diagnosis is still mainly based on 2D imaging techniques. Three-dimensional tomographic imaging with whole-body PET or SPECT scanners, when used for imaging the breast, has performance limits in terms of spatial resolution and sensitivity, which can be overcome only with a dedicated instrumentation. However, only few hybrid imaging systems for PET/CT or SPECT/CT dedicated to the breast have been developed in the last decade, providing complementary functional and anatomical information on normal breast tissue and lesions. These systems are still under development and clinical trials on just few patients have been reported; no commercial dedicated breast PET/CT or SPECT/CT is available. This paper reviews combined dedicated breast PET/CT and SPECT/CT scanners described in the recent literature, with focus on their technological aspects.

CT portography by multidetector helical CT. Comparison of three rendering models

International Nuclear Information System (INIS)

Nakayama, Yoshiharu; Imuta, Masanori; Funama, Yoshinori; Kadota, Masataka; Utsunomiya, Daisuke; Shiraishi, Shinya; Hayashida, Yoshiko; Yamashita, Yasuyuki

2002-01-01

The purpose of this study was to assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). A total of 46 patients with portal hypertension were examined by CT and conventional portography for evaluation of portosystemic collaterals. CT portography was performed by multidetector CT (MD-CT) scanner with a slice thickness of 2.5 mm and table feed of 7.5 mm. Three types of CT portographic models were generated and compared with transarterial portography. Among 46 patients, 48 collaterals were identified on CT transverse images, while 38 collaterals were detected on transarterial portography. Forty-four of 48 collaterals identified on CT transverse images were visualized with the MIP model, while 34 and 29 collaterals were visualized by the VR and SSD methods, respectively. The average CT value for the portal vein and varices was 198 HU with data acquisition of 50 sec after contrast material injection. CT portography by multidetector CT provides excellent images in the visualization of portosystemic collaterals. The images of collaterals produced by MD-CT are superior to those of transarterial portography. Among the three rendering techniques, MIP provides the best visualization of portosystemic collaterals. (author)

CT portography by multidetector helical CT. Comparison of three rendering models

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Nakayama, Yoshiharu; Imuta, Masanori; Funama, Yoshinori; Kadota, Masataka; Utsunomiya, Daisuke; Shiraishi, Shinya; Hayashida, Yoshiko; Yamashita, Yasuyuki [Kumamoto Univ. (Japan). School of Medicine

2002-12-01

The purpose of this study was to assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). A total of 46 patients with portal hypertension were examined by CT and conventional portography for evaluation of portosystemic collaterals. CT portography was performed by multidetector CT (MD-CT) scanner with a slice thickness of 2.5 mm and table feed of 7.5 mm. Three types of CT portographic models were generated and compared with transarterial portography. Among 46 patients, 48 collaterals were identified on CT transverse images, while 38 collaterals were detected on transarterial portography. Forty-four of 48 collaterals identified on CT transverse images were visualized with the MIP model, while 34 and 29 collaterals were visualized by the VR and SSD methods, respectively. The average CT value for the portal vein and varices was 198 HU with data acquisition of 50 sec after contrast material injection. CT portography by multidetector CT provides excellent images in the visualization of portosystemic collaterals. The images of collaterals produced by MD-CT are superior to those of transarterial portography. Among the three rendering techniques, MIP provides the best visualization of portosystemic collaterals. (author)

CT arterial portography and CT arteriography with a triple-lumen balloon catheter

International Nuclear Information System (INIS)

Murakami, T.; Oi, H.; Hori, M.; Kim, T.; Takahashi, S.; Matsushita, M.; Narumi, Y.; Nakamura, H.

1997-01-01

Purpose: To evaluate the usefulness of the triple-lumen balloon catheter in the serial performance of CT arterial portography (CT-AP) and CT arteriography (CT-A). Material and Methods: A combined CT-AP and CT-A examination of 58 patients was carried out in which a cobra-type triple-lumen balloon catheter was used. CT-AP was performed by injecting contrast medium either into the splenic artery through a side-hole in the catheter proximal to the balloon inflated in the common hepatic artery, or into the superior mesentric artery through an end-hole in the catheter. Then CT-A was serially performed by delivering contrast medium either to the common hepatic artery or the proper hepatic artery from the end-hole, or to the accessory right hepatic artery through a side-hole proximal to the inflated balloon. Results: Sufficient CT-APs were obtained in 53 of the 58 patients (91%), CT-A in 42 (72%), and both in 42 (72%). Incomplete CT-AP was due to technical failure or anatomical anomaly, as was incomplete CT-A. No complications were seen. (orig.)

CT-Urography; Urografia CT

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Dalla Palma, Ludovico; Grotto, Maurizio [Trieste Univ., Trieste (Italy). Dipartimento di scienze cliniche, morfologiche e tecnologiche, UCO di radiologia; Morra, Aldo [CRO, Aviano (Italy). Reparto di radiologia

2005-09-15

In this paper we present an overview of CT-Urography. With the advent of multislice CT scanners and the evolution of image processing methods this technique now affords optimal urographic images comparable to those obtained with conventional techniques. We describe the acquisition techniques and protocols used by the various authors. Effective radiation dose has conditioned the use of CT-Urography so that the tendency today is to reduce the number of scans by performing, after the non enhanced scan, a single contrast-enhanced scan comprising both the nephrographic and urographic phase. With the use of multislice CT the quality of the urogram improves with the number of slices. We illustrate a variety of processing techniques, multiplanar reconstruction (MPR), maximum (MIP) and average intensity projection (AIP) and volume rendering (VR) and present a series of upper urinary tract tumours testifying to the superiority of the AIP technique over MIP. We then review the results of comparative studies of CT-Urography with conventional urography in upper urinary tract diagnostics. Finally, we describe the advantages and limitations of CT-Urography. [Italian] Gli Autori presentano una panoramica sulla Urografia TC (Uro TC). L'avvento della TC multistrato e l'evoluzione delle tecniche di elaborazione consentono di ottenere dei quadri urografici ottimali comparativi con quelli convenzionali. Vengono ricordate le varie tecniche di acquisizione e i protocolli usati dai vari Autori. La dose effettiva di radiazioni ha rappresentato uno dei fattori condizionanti per cui oggi prevale l'orientamento di ridurre il numero di scansioni, considerando dopo la scansione senza mezzo di contrasto un'unica scansione contrasto grafica comprendente sia la fase nefrografica che quella urografica. Con l'uso della TC multistrato la qualita dell'urogramma migliora con l'aumento del numero degli strati. Vengono descritte le varie tecniche di elaborazione, la

Comparison of CT and PET/CT for biopsy guidance in oncological patients

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Cerci, Juliano J.; Bogoni, Mateos; Cunha Pereira, Carlos; Cerci, Rodrigo J.; Krauzer, Cassiano; Vicente Vitola, Joao [Quanta - Diagnostico e Terapia, Curitiba, PR (Brazil); Tabacchi, Elena; Fanti, Stefano [University Hospital S. Orsola-Malpighi, Nuclear Medicine Department, Bologna (Italy); Delbeke, Dominique [Vanderbilt University, Nashville, TN (United States); Giacometti Sakamoto, Danielle [Byori - Laboratorio de Patologia, Curitiba (Brazil)

2017-08-15

To compare FDG PET/CT and CT for the guidance of percutaneous biopsies with histological confirmation of lesions. We prospectively evaluated 323 patients of whom 181 underwent FDG PET/CT-guided biopsy (total 188 biopsies) and 142 underwent CT-guided biopsy (total 146 biopsies). Biopsies were performed using the same PET/CT scanner with a fluoroscopic imaging system. Technical feasibility, clinical success and complication rates in the two groups were evaluated. Of the 188 biopsies with PET/CT guidance, 182 (96.8%) were successful with conclusive tissue samples obtained and of the 146 biopsies with CT guidance, 137 (93.8%) were successful. Therefore, 6 of 188 biopsies (3.1%) with PET/CT guidance and 9 of 146 (6.1%) with CT guidance were inconclusive (p = 0.19). Due to inconclusive histological results, 4 of the 188 lesions (2.1%) were rebiopsied with PET/CT guidance and 3 of 146 lesions (2.0%) were rebiopsied with CT guidance. Histology demonstrated that 142 of 188 lesions (75.5%) were malignant, and 40 (21.2%) were benign in the PET/CT-guided group, while 89 of 146 lesions (60.9%) were malignant and 48 (32.8%) were benign in the CT-guided group (p = 0.004 and 0.01, respectively). Patients with a histological diagnosis of benign lesion had no recurrence of disease with a minimum of 6 months follow-up. Of the 188 PET/CT-guided biopsies, 6 (3.1%) were repeat biopsies due to a previous nondiagnostic CT-guided biopsy performed in a different diagnostic centre. The interval between the two biopsies was less than a month in all cases. Histology revealed five malignant lesions and one benign lesion among these. The complication rate in the PET/CT-guided biopsy group was 12.7% (24 of 188), while in the CT-guided group, was 9.5% (14 of 146, p = 0.26). Therefore, there was no significant difference in complication rates between PET/CT and CT guidance. PET/CT-guided biopsy is already known to be a feasible and accurate method in the diagnostic work-up of suspected malignant

Comparison of CT and PET/CT for biopsy guidance in oncological patients

International Nuclear Information System (INIS)

Cerci, Juliano J.; Bogoni, Mateos; Cunha Pereira, Carlos; Cerci, Rodrigo J.; Krauzer, Cassiano; Vicente Vitola, Joao; Tabacchi, Elena; Fanti, Stefano; Delbeke, Dominique; Giacometti Sakamoto, Danielle

2017-01-01

To compare FDG PET/CT and CT for the guidance of percutaneous biopsies with histological confirmation of lesions. We prospectively evaluated 323 patients of whom 181 underwent FDG PET/CT-guided biopsy (total 188 biopsies) and 142 underwent CT-guided biopsy (total 146 biopsies). Biopsies were performed using the same PET/CT scanner with a fluoroscopic imaging system. Technical feasibility, clinical success and complication rates in the two groups were evaluated. Of the 188 biopsies with PET/CT guidance, 182 (96.8%) were successful with conclusive tissue samples obtained and of the 146 biopsies with CT guidance, 137 (93.8%) were successful. Therefore, 6 of 188 biopsies (3.1%) with PET/CT guidance and 9 of 146 (6.1%) with CT guidance were inconclusive (p = 0.19). Due to inconclusive histological results, 4 of the 188 lesions (2.1%) were rebiopsied with PET/CT guidance and 3 of 146 lesions (2.0%) were rebiopsied with CT guidance. Histology demonstrated that 142 of 188 lesions (75.5%) were malignant, and 40 (21.2%) were benign in the PET/CT-guided group, while 89 of 146 lesions (60.9%) were malignant and 48 (32.8%) were benign in the CT-guided group (p = 0.004 and 0.01, respectively). Patients with a histological diagnosis of benign lesion had no recurrence of disease with a minimum of 6 months follow-up. Of the 188 PET/CT-guided biopsies, 6 (3.1%) were repeat biopsies due to a previous nondiagnostic CT-guided biopsy performed in a different diagnostic centre. The interval between the two biopsies was less than a month in all cases. Histology revealed five malignant lesions and one benign lesion among these. The complication rate in the PET/CT-guided biopsy group was 12.7% (24 of 188), while in the CT-guided group, was 9.5% (14 of 146, p = 0.26). Therefore, there was no significant difference in complication rates between PET/CT and CT guidance. PET/CT-guided biopsy is already known to be a feasible and accurate method in the diagnostic work-up of suspected malignant

Optimization of Protocol CT, PET-CT, whole body; Optimizacion de protocolo CT, en PET-CT, de cuerpo entero

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Gutierrez, Fredys Santos, E-mail: fsantos@ccss.sa.cr [Caja Costarricense de Seguro Social (ACCPR/CCSS), San Jose (Costa Rica). Area Control de Calidade Y Proteccion Radiologica; Namias, Mauro, E-mail: mnamias@gmail.com [Comision Nacional de Energia Atomica (FCDN/CNEA), Buenos Aires (Argentina). Fundacion Centro Diagnostico Nuclear

2013-11-01

The objective of this study was to optimize the acquisition protocols and processing existing of the CT PET/CT scanner for clinical use of Nuclear Diagnostic Center Foundation, a way to minimize the radiation dose while maintaining diagnostic image quality properly. Dosimetric data of PET / CT service were surveyed and obtained the baseline against which we compare and define strategies and modifications to develop online. We selected transaxial up to the pulmonary hilum and liver slices as the anatomical regions of interest that led to the standardization of the study.

New possibilities in the diagnosis of ischemia. CT-FFR and CT-Perfusion; Neue Moeglichkeiten der Ischaemiediagnostik. CT-FFR und CT-Perfusion

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Lehmkuhl, Lukas [Herz- und Gefaessklinik, Bad Neustadt an der Saale (Germany). Abt. fuer Radiologie; Krieghoff, Christian [Herzzentrum Leipzig (Germany); Gutberlet, Matthias [Herzzentrum Leipzig (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie; Leipzig Univ. (Germany). Kardiologische Bildgebung

2017-12-15

Coronary CT-angiography (CCTA) plays an increasing role in the primary diagnostics of coronary artery disease (CAD) according to the present guidelines but also in clinical reality. The sensitivity and negative predictive value of CCTA is very high, but the specificity could still be improved. Newer techniques to assess myocardial ischemia like CT-FFR and CT-Perfusion may help to achieve that goal.

Cost-effectiveness modeling of colorectal cancer: Computed tomography colonography vs colonoscopy or fecal occult blood tests

International Nuclear Information System (INIS)

Lucidarme, Olivier; Cadi, Mehdi; Berger, Genevieve; Taieb, Julien; Poynard, Thierry; Grenier, Philippe; Beresniak, Ariel

2012-01-01

Objectives: To assess the cost-effectiveness of three colorectal-cancer (CRC) screening strategies in France: fecal-occult-blood tests (FOBT), computed-tomography-colonography (CTC) and optical-colonoscopy (OC). Methods: Ten-year simulation modeling was used to assess a virtual asymptomatic, average-risk population 50–74 years old. Negative OC was repeated 10 years later, and OC positive for advanced or non-advanced adenoma 3 or 5 years later, respectively. FOBT was repeated biennially. Negative CTC was repeated 5 years later. Positive CTC and FOBT led to triennial OC. Total cost and CRC rate after 10 years for each screening strategy and 0–100% adherence rates with 10% increments were computed. Transition probabilities were programmed using distribution ranges to account for uncertainty parameters. Direct medical costs were estimated using the French national health insurance prices. Probabilistic sensitivity analyses used 5000 Monte Carlo simulations generating model outcomes and standard deviations. Results: For a given adherence rate, CTC screening was always the most effective but not the most cost-effective. FOBT was the least effective but most cost-effective strategy. OC was of intermediate efficacy and the least cost-effective strategy. Without screening, treatment of 123 CRC per 10,000 individuals would cost €3,444,000. For 60% adherence, the respective costs of preventing and treating, respectively 49 and 74 FOBT-detected, 73 and 50 CTC-detected and 63 and 60 OC-detected CRC would be €2,810,000, €6,450,000 and €9,340,000. Conclusion: Simulation modeling helped to identify what would be the most effective (CTC) and cost-effective screening (FOBT) strategy in the setting of mass CRC screening in France.

CT of laryngotracheal trauma

International Nuclear Information System (INIS)

Lupetin, A.R.; Daffner, R.H.

1991-01-01

This paper evaluates the usefulness of CT for the diagnosis of traumatic laryngotracheal abnormalities. The authors retrospectively evaluated the neck CT studies of 50 patients (36 males, 14 females; age range, 16-75 years) who presented to a level I trauma center after suffering a blunt or penetrating laryngotracheal injury. CT results were correlated with endoscopic or surgical findings in 43 cases. Three groups emerge. CT positive: hyloid bone or laryngotracheal cartilage injury; CT positive: soft-tissue injury only; and CT negative. In group 1, CT demonstrated all bony or cartilaginous injuries proved at surgery or suggested at endoscopy. CT failed to demonstrate laryngotracheal separation in 1 case. In group 2, CT demonstrated all soft-tissue injuries suggested at endoscopy. In group 3, CT findings agreed with those of endoscopy in 7 cases, but minor soft-tissue findings seen at endoscopy were missed in 3 cases. Seven patients were studied only with CT. Ct is an accurate technique for detecting bony or cartilaginous laryngotracheal traumatic abnormalities. However, laryngotracheal separation and minor soft-tissue injuries can be missed

CT-Urography

International Nuclear Information System (INIS)

Dalla Palma, Ludovico; Grotto, Maurizio; Morra, Aldo

2005-01-01

In this paper we present an overview of CT-Urography. With the advent of multislice CT scanners and the evolution of image processing methods this technique now affords optimal urographic images comparable to those obtained with conventional techniques. We describe the acquisition techniques and protocols used by the various authors. Effective radiation dose has conditioned the use of CT-Urography so that the tendency today is to reduce the number of scans by performing, after the non enhanced scan, a single contrast-enhanced scan comprising both the nephrographic and urographic phase. With the use of multislice CT the quality of the urogram improves with the number of slices. We illustrate a variety of processing techniques, multiplanar reconstruction (MPR), maximum (MIP) and average intensity projection (AIP) and volume rendering (VR) and present a series of upper urinary tract tumours testifying to the superiority of the AIP technique over MIP. We then review the results of comparative studies of CT-Urography with conventional urography in upper urinary tract diagnostics. Finally, we describe the advantages and limitations of CT-Urography [it

CT vs 68Ge attenuation correction in a combined PET/CT system: evaluation of the effect of lowering the CT tube current

International Nuclear Information System (INIS)

Kamel, Ehab; Hany, Thomas F.; Burger, Cyrill; Treyer, Valerie; Schulthess von, Gustav K.; Buck, Alfred; Lonn, Albert H.R.

2002-01-01

With the introduction of combined positron emission tomography/computed tomography (PET/CT) systems, several questions have to be answered. In this work we addressed two of these questions: (a) to what value can the CT tube current be reduced while still yielding adequate maps for the attenuation correction of PET emission scans and (b) how do quantified uptake values in tumours derived from CT and germanium-68 attenuation correction compare. In 26 tumour patients, multidetector CT scans were acquired with 10, 40, 80 and 120 mA (CT 10 , CT 40 , CT 80 and CT 120 ) and used for the attenuation correction of a single FDG PET emission scan, yielding four PET scans designated PET CT10 -PET CT120 . In 60 tumorous lesions, FDG uptake and lesion size were quantified on PET CT10 -PET CT120 . In another group of 18 patients, one CT scan acquired with 80 mA and a standard transmission scan acquired using 68 Ge sources were employed for the attenuation correction of the FDG emission scan (PET CT80 , PET 68Ge ). Uptake values and lesion size in 26 lesions were compared on PET CT80 and PET 68Ge . In the first group of patients, analysis of variance revealed no significant effect of CT current on tumour FDG uptake or lesion size. In the second group, tumour FDG uptake was slightly higher using CT compared with 68 Ge attenuation correction, especially in lesions with high FDG uptake. Lesion size was similar on PET CT80 and PET 68Ge . In conclusion, low CT currents yield adequate maps for the attenuation correction of PET emission scans. Although the discrepancy between CT- and 68 Ge-derived uptake values is probably not relevant in most cases, it should be kept in mind if standardised uptake values derived from CT and 68 Ge attenuation correction are compared. (orig.)

Image Registration for PET/CT and CT Images with Particle Swarm Optimization

International Nuclear Information System (INIS)

Lee, Hak Jae; Kim, Yong Kwon; Lee, Ki Sung; Choi, Jong Hak; Kim, Chang Kyun; Moon, Guk Hyun; Joo, Sung Kwan; Kim, Kyeong Min; Cheon, Gi Jeong

2009-01-01

Image registration is a fundamental task in image processing used to match two or more images. It gives new information to the radiologists by matching images from different modalities. The objective of this study is to develop 2D image registration algorithm for PET/CT and CT images acquired by different systems at different times. We matched two CT images first (one from standalone CT and the other from PET/CT) that contain affluent anatomical information. Then, we geometrically transformed PET image according to the results of transformation parameters calculated by the previous step. We have used Affine transform to match the target and reference images. For the similarity measure, mutual information was explored. Use of particle swarm algorithm optimized the performance by finding the best matched parameter set within a reasonable amount of time. The results show good agreements of the images between PET/CT and CT. We expect the proposed algorithm can be used not only for PET/CT and CT image registration but also for different multi-modality imaging systems such as SPECT/CT, MRI/PET and so on.

The effect of the cranial bone CT numbers on the brain CT numbers

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Hitoshi; Kobayashi, Shotai; Koide, Hiromi; Yamaguchi, Shuhei; Okada, Kazunori; Shimote, Koichi; Tsunematsu, Tokugoro (Shimane Medical Univ., Izumo (Japan))

1989-06-01

The effects of the cranial size and the computed tomography (CT) numbers of the cranial bone on that of the brain were studied in 70 subjects, aged from 30 to 94 years. The subjects had no histories of cerebrovascular accidents and showed no abnormalities in the central nervous system upon physical examinations and a CT scan. We measured the average attenuation values (CT numbers) of each elliptical region (165 pixels, 0.39 cm{sup 2}) at the bilateral thalamus and at twelve areas of the deep white matter. Multiple regression analysis was used to assess the effects of age, cranial size, and cranial bone CT numbers on the brain CT numbers. The effect of the cranial bone CT numbers on the brain CT numbers was statistically significant. The brain CT numbers increased with the increase in the cranial bone CT numbers. There was, however, no significant correlation between brain CT numbers and cranial size. In measuring the brain CT numbers, it is desirable that consideration be given to the cranial bone CT numbers. (author).

Bone quality evaluation at dental implant site using multislice CT, micro-CT, and cone beam CT.

Science.gov (United States)

Parsa, Azin; Ibrahim, Norliza; Hassan, Bassam; van der Stelt, Paul; Wismeijer, Daniel

2015-01-01

The first purpose of this study was to analyze the correlation between bone volume fraction (BV/TV) and calibrated radiographic bone density Hounsfield units (HU) in human jaws, derived from micro-CT and multislice computed tomography (MSCT), respectively. The second aim was to assess the accuracy of cone beam computed tomography (CBCT) in evaluating trabecular bone density and microstructure using MSCT and micro-CT, respectively, as reference gold standards. Twenty partially edentulous human mandibular cadavers were scanned by three types of CT modalities: MSCT (Philips, Best, the Netherlands), CBCT (3D Accuitomo 170, J Morita, Kyoto, Japan), and micro-CT (SkyScan 1173, Kontich, Belgium). Image analysis was performed using Amira (v4.1, Visage Imaging Inc., Carlsbad, CA, USA), 3Diagnosis (v5.3.1, 3diemme, Cantu, Italy), Geomagic (studio(®) 2012, Morrisville, NC, USA), and CTAn (v1.11, SkyScan). MSCT, CBCT, and micro-CT scans of each mandible were matched to select the exact region of interest (ROI). MSCT HU, micro-CT BV/TV, and CBCT gray value and bone volume fraction of each ROI were derived. Statistical analysis was performed to assess the correlations between corresponding measurement parameters. Strong correlations were observed between CBCT and MSCT density (r = 0.89) and between CBCT and micro-CT BV/TV measurements (r = 0.82). Excellent correlation was observed between MSCT HU and micro-CT BV/TV (r = 0.91). However, significant differences were found between all comparisons pairs (P micro-CT BV/TV (P = 0.147). An excellent correlation exists between bone volume fraction and bone density as assessed on micro-CT and MSCT, respectively. This suggests that bone density measurements could be used to estimate bone microstructural parameters. A strong correlation also was found between CBCT gray values and BV/TV and their gold standards, suggesting the potential of this modality in bone quality assessment at implant site. © 2013 John Wiley & Sons A/S. Published by

Combined CT Angiography and CT Venography in Thromboembolic disease: clinical impact

International Nuclear Information System (INIS)

Bouzas, R.; Migueles, Y.; Gomez, S.; Mallo, R.; Garcia-Tejedor, J. L.; Diaz Vega, M. J.

2002-01-01

Combined CT Venography and Pulmonary Angiography was described in 1998 as a tool for diagnostic Thromboembolic Disease. The purpose is to relate our own experience with this technique in a population with suspected pulmonary embolism. 46 consecutive patients with suspected pulmonary embolism underwent combined CT Venography after Pulmonary CT Angiography to depict Deep Venous Thrombosis (DVT). CT Venography where obtained with a 3 minutes delay from injection, without additional intravenous contrast, from upper abdomen to fibular head. A prospective study from emergency reports where used. The reports where aimed by nine different radiologist at diary emergency room (images where not retrospective review). We report if a pulmonary embolus or deep venous thrombus or another alternative diagnostic where done. An endo luminal thrombus in any pulmonary arteries was assessed as a positive study for PE. A Thrombus in the leg veins or in an abdominal vein without diminished size of vein was assessed as an acute DVT. In those patients with a CT negative to Thromboembolic Disease was the clinician who decide if more proves where needed. Those patients without evidence in CT of Thromboembolic Disease where asked for symptoms related to the episode in a 3 months period after initial CT. Patients free of symptoms for 3 months without anticoagulation therapy where considered true negative for CT. CT shows Thromboembolic Disease in 23 of 46 patients. 21PE, 14 DVT 2 of 14 patients with DVT don't show PE, CT excluded thromboembolic disease in 23 patients and in 15 of those patients an alternative diagnostic was shown. In 22 of those 23 patients CT excluded correctly Thromboembolic Disease. One patient result in a false negative CT, Pulmonary Angiography of that patient shows us a subsegmentary embolus. (Author) 9 refs

Picture analysis in CT-HF and its CT photographs

International Nuclear Information System (INIS)

Kubota, Kazuo; Kohirasawa, Hideo; Shinojima, Masayasu; Tokui, Mitsuru; Seo, Kunihiko.

1980-01-01

CT (computed tomography) apparatus is rarely used yet in the field of dentistry, though it seems useful. It is possibly because of the artefacts caused by the metallic parts attached to teeth, the large partial volume effect due to many bones and the problems of positioning and reproducibility. After considering the various requirements of the CT apparatuses in dental field, CT-HF (of T/R type) was chosen as such apparatus, and installed as the first in dentistry. In the CT-HF apparatus, the inner diameter of the gantry is up to 300 mm, and the position of a tomographic plane is only 40 mm away from the front of gantry. Mainly the usefulness of scanography in positioning and the usefulness of the CT apparatus in the picture analysis and processing in dental field are described. (J.P.N.)

Additional value of PET-CT in the staging of lung cancer: comparison with CT alone, PET alone and visual correlation of PET and CT

International Nuclear Information System (INIS)

Wever, W. de; Marchal, G.; Bogaert, J.; Verschakelen, J.A.; Ceyssens, S.; Mortelmans, L.; Stroobants, S.

2007-01-01

Integrated positron emission tomography (PET) and computed tomography (CT) is a new imaging modality offering anatomic and metabolic information. The purpose was to evaluate retrospectively the accuracy of integrated PET-CT in the staging of a suggestive lung lesion, comparing this with the accuracy of CT alone, PET alone and visually correlated PET-CT. Fifty patients undergoing integrated PET-CT for staging of a suggestive lung lesion were studied. Their tumor, node, metastasis (TNM) statuses were determined with CT, PET, visually correlated PET-CT and integrated PET-CT. These TNM stages were compared with the surgical TNM status. Integrated PET-CT was the most accurate imaging technique in the assessment of the TNM status. Integrated PET-CT predicted correctly the T status, N status, M status and TNM status in, respectively, 86%, 80%, 98%, 70% versus 68%, 66%,88%, 46% with CT, 46%, 70%, 96%, 30% with PET and 72%, 68%, 96%, 54% with visually correlated PET-CT. T status and N status were overstaged, respectively, in 8% and 16% with integrated PET-CT, in 20% and 28% with CT, in 16% and 20% with PET, in 12% and 20% with visually correlated PET-CT and understaged in 6% and 4% with integrated PET-CT, versus 12% and 6% with CT, 38% and 10% with PET and 12% with visually correlated PET-CT. Integrated PET-CT improves the staging of lung cancer through a better anatomic localization and characterization of lesions and is superior to CT alone and PET alone. If this technique is not available, visual correlation of PET and CT can be a valuable alternative. (orig.)

Automated polyp measurement based on colon structure decomposition for CT colonography

Science.gov (United States)

Wang, Huafeng; Li, Lihong C.; Han, Hao; Peng, Hao; Song, Bowen; Wei, Xinzhou; Liang, Zhengrong

2014-03-01

Accurate assessment of colorectal polyp size is of great significance for early diagnosis and management of colorectal cancers. Due to the complexity of colon structure, polyps with diverse geometric characteristics grow from different landform surfaces. In this paper, we present a new colon decomposition approach for polyp measurement. We first apply an efficient maximum a posteriori expectation-maximization (MAP-EM) partial volume segmentation algorithm to achieve an effective electronic cleansing on colon. The global colon structure is then decomposed into different kinds of morphological shapes, e.g. haustral folds or haustral wall. Meanwhile, the polyp location is identified by an automatic computer aided detection algorithm. By integrating the colon structure decomposition with the computer aided detection system, a patch volume of colon polyps is extracted. Thus, polyp size assessment can be achieved by finding abnormal protrusion on a relative uniform morphological surface from the decomposed colon landform. We evaluated our method via physical phantom and clinical datasets. Experiment results demonstrate the feasibility of our method in consistently quantifying the size of polyp volume and, therefore, facilitating characterizing for clinical management.

Metal artifact reduction of CT scans to improve PET/CT

NARCIS (Netherlands)

Van Der Vos, Charlotte S.; Arens, Anne I.J.; Hamill, James J.; Hofmann, Christian; Panin, Vladimir Y.; Meeuwis, Antoi P.W.; Visser, Eric P.; De Geus-Oei, Lioe Fee

2017-01-01

In recent years, different metal artifact reduction methods have been developed for CT. These methods have only recently been introduced for PET/CT even though they could be beneficial for interpretation, segmentation, and quantification of the PET/CT images. In this study, phantom and patient scans

Metal Artifact Reduction of CT Scans to Improve PET/CT

NARCIS (Netherlands)

Vos, C.S. van der; Arens, A.I.J.; Hamill, J.J.; Hofmann, C.; Panin, V.Y.; Meeuwis, A.P.W.; Visser, E.P.; Geus-Oei, L.F. de

2017-01-01

In recent years, different metal artifact reduction methods have been developed for CT. These methods have only recently been introduced for PET/CT even though they could be beneficial for interpretation, segmentation, and quantification of the PET/CT images. In this study, phantom and patient scans

Restaging of patients with lymphoma. Comparison of low dose CT (20 mAs) with contrast enhanced diagnostic CT in combined [18F]-FDG PET/CT

International Nuclear Information System (INIS)

Fougere, C. la; Pfluger, T.; Schneider, V.; Hacker, M.; Broeckel, N.; Bartenstein, P.; Tiling, R.; Morhard, D.; Hundt, W.; Becker, C.

2008-01-01

Aim: assessment of the clinical benefit of i.v. contrast enhanced diagnostic CT (CE-CT) compared to low dose CT with 20 mAs (LD-CT) without contrast medium in combined [ 18 F]-FDG PET/CT examinations in restaging of patients with lymphoma. Patients, methods: 45 patients with non-Hodgkin lymphoma (n = 35) and Hodgkin's disease (n = 10) were included into this study. PET, LD-CT and CE-CT were analyzed separately as well as side-by-side. Lymphoma involvement was evaluated separately for seven regions. Indeterminate diagnoses were accepted whenever there was a discrepancy between PET and CT findings. Results for combined reading were calculated by rating indeterminate diagnoses according the suggestions of either CT or PET. Each patient had a clinical follow-up evaluation for > 6 months. Results: region-based evaluation suggested a sensitivity/specificity of 66/93% for LD-CT, 87%/91% for CE-CT, 95%/96% for PET, 94%/99% for PET/LD-CT and 96%/99% for PET/CE-CT. The data for PET/CT were obtained by rating indeterminate results according to the suggestions of PET, which turned out to be superior to CT. Lymphoma staging was changed in two patients using PET/CE-CT as compared to PET/LD-CT. Conclusion: overall, there was no significant difference between PET/LD-CT and PET/CE-CT. However, PET/CE-CT yielded a more precise lesion delineation than PET/LD-CT. This was due to the improved image quality of CE-CT and might lead to a more accurate investigation of lymphoma. (orig.)

CT and PET-CT of a Dog with Multiple Pulmonary Adenocarcinoma

Science.gov (United States)

KIM, Jisun; KWON, Seong Young; CENA, Rohani; PARK, Seungjo; OH, Juyeon; OUI, Heejin; CHO, Kyoung-Oh; MIN, Jung-Joon; CHOI, Jihye

2013-01-01

ABSTRACT A 10-year-old, intact female Yorkshire terrier had multiple pulmonary nodules on thoracic radiography and ultrasonography with no lesions elsewhere. Computed tomography (CT) and positron emission tomography and computed tomography (PET-CT) using 18F-fluorodeoxyglucose (FDG) were performed to identify metastasis and undetected primary tumors. On CT examination, pulmonary nodules had a hypoattenuating center with thin peripheral enhancement, suggesting ischemic or necrotizing lesion. In PET-CT at 47 min after intravenous injection of 11.1 MBq/kg of FDG, the maximum standardized uptake value of each pulmonary nodule was about from 3.8 to 6.4. There were no abnormal lesions except for four pulmonary nodules on the CT and PET-CT. Primary lung tumor was tentatively diagnosed, and palliative therapy using 2 mg/kg tramadol and 2.2 mg/kg carprofen twice per day was applied. After the dog’s euthanasia due to deteriorated clinical signs and poor prognosis, undifferentiated pulmonary adenocarcinoma was diagnosed through histopathologic and immunochemistry examination. To the best of the authors’ knowledge, this is the first study of CT and PET-CT features of canine pulmonary adenocarcinoma. In this case, multiple pulmonary adenocarcinoma could be determined on the basis of FDG PET-CT through screening the obvious distant metastasis and/or lymph node invasions and excluding unknown primary tumors. PMID:24389742

CT paging arteriography with a multidetector-row CT. Advantages in splanchnic arterial imaging

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Seiji [Keio Univ., Tokyo (Japan). School of Medicine

1999-11-01

The purpose of this study is to assess the utility of CT paging arteriography with a multidetector-row CT as a replacement for conventional angiography in the evaluation of splanchnic arterial anomalies. Sixty-three patients underwent CT paging arteriography with a multidetector-row CT. In the 56 patients with conventional angiographic correlation, there was only one minor disagreement with CT paging arteriography. In the 7 patients who underwent IVDSA (intra venous digital subtraction angiography), CT paging arteriography defined four hepatic arterial anomalies which could not be depicted by IVDSA. In conclusion, CT paging arteriography provides noninvasive means to identify splanchnic arterial anomalies. (author)

Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT studies for the diagnosis of uterine cancer recurrence

Energy Technology Data Exchange (ETDEWEB)

Kitajima, Kazuhiro [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Suzuki, Kayo [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Nakamoto, Yuji [Kyoto University Hospital, Department of Diagnostic Radiology, Kyoto (Japan); Onishi, Yumiko; Sakamoto, Setsu; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Senda, Michio [Institute of Biomedical Research and Innovation, Department of Molecular Imaging, Kobe (Japan); Kita, Masato [Kobe City Medical Center General Hospital, Department of Obstetrics and Gynecology, Kobe (Japan)

2010-08-15

To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated {sup 18}F-fluorodeoxyglucose (FDG) PET/CT studies for restaging of uterine cancer. A group of 100 women who had undergone treatment for uterine cervical (n=55) or endometrial cancer (n=45) underwent a conventional PET/CT scans with ldCT, and then a ceCT scan. Two observers retrospectively reviewed and interpreted the PET/ldCT and PET/ceCT images in consensus using a three-point grading scale (negative, equivocal, or positive) per patient and per lesion. Final diagnoses were obtained by histopathological examination, or clinical follow-up for at least 6 months. Patient-based analysis showed that the sensitivity, specificity and accuracy of PET/ceCT were 90% (27/30), 97% (68/70) and 95% (95/100), respectively, whereas those of PET/ldCT were 83% (25/30), 94% (66/70) and 91% (91/100), respectively. Sensitivity, specificity and accuracy did not significantly differ between two methods (McNemar test, p=0.48, p=0.48, and p=0.13, respectively). There were 52 sites of lesion recurrence: 12 pelvic lymph node (LN), 11 local recurrence, 8 peritoneum, 7 abdominal LN, 5 lung, 3 supraclavicular LN, 3 liver, 2 mediastinal LN, and 1 muscle and bone. The grading results for the 52 sites of recurrence were: negative 5, equivocal 0 and positive 47 for PET/ceCT, and negative 5, equivocal 4 and positive 43 for PET/ldCT, respectively. Four equivocal regions by PET/ldCT (local recurrence, pelvic LN metastasis, liver metastasis and muscle metastasis) were correctly interpreted as positive by PET/ceCT. PET/ceCT is an accurate imaging modality for the assessment of uterine cancer recurrence. Its use reduces the frequency of equivocal interpretations. (orig.)

Computed Tomography (CT) -- Sinuses

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Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses ... CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known ...

Spinal CT scan, 1

International Nuclear Information System (INIS)

Nakagawa, Hiroshi

1982-01-01

Methods of CT of the cervical and thoracic spines were explained, and normal CT pictures of them were described. Spinal CT was evaluated in comparison with other methods in various spinal diseases. Plain CT revealed stenosis due to spondylosis or ossification of posterior longitudinal ligament and hernia of intervertebral disc. CT took an important role in the diagnosis of spinal cord tumors with calcification and destruction of the bone. CT scan in combination with other methods was also useful for the diagnosis of spinal injuries, congenital anomalies and infections. (Ueda, J.)

Differentiation between benign and malignant colon tumors using fast dynamic gadolinium-enhanced MR colonography; a feasibility study

International Nuclear Information System (INIS)

Achiam, M.P.; Andersen, L.P.H.; Klein, M.; Logager, V.; Chabanova, E.; Thomsen, H.S.; Rosenberg, J.

2010-01-01

Background: Colorectal cancer will present itself as a bowel obstruction in 16-23% of all cases. However, not all obstructing tumors are malignant and the differentiation between a benign and a malignant tumor can be difficult. The purpose of our study was to determine whether fast dynamic gadolinium-enhanced MR imaging combined with MR colonography could be used to differentiate a benign from a malignant obstructing colon tumor. Methods: Patients with benign colon tumor stenosis, based on diverticulitis, were asked to participate in the study. The same number of patients with verified colorectal cancer was included. Both groups had to be scheduled for surgery to be included. Two blinded observers analyzed the tumors on MR by placing a region of interest in the tumor and a series of parameters were evaluated, e.g. wash-in, wash-out and time-to-peak. Results: 14 patients were included. The wash-in and wash-out rates were significantly different between the benign and malignant tumors, and a clear distinction between benign and malignant disease was therefore possible by looking only at the MR data. Furthermore, MR colography evaluating the rest of the colon past the stenosis was possible with all patients. Conclusion: The results showed the feasibility of using fast dynamic gadolinium-enhanced MR imaging to differentiate between benign and malignant colonic tumors. With a high intra-class correlation and significant differences found on independent segments of the tumor, the method appears to be reproducible. Furthermore, the potential is big in performing a full preoperative colon evaluation even in patients with obstructing cancer. Trial number: (NCT00114829).

Differentiation between benign and malignant colon tumors using fast dynamic gadolinium-enhanced MR colonography; a feasibility study

Energy Technology Data Exchange (ETDEWEB)

Achiam, M.P., E-mail: achiam1@dadlnet.d [Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev Ringvej, DK-2730 Herlev (Denmark); Department of Surgical Gastroenterology D, Copenhagen University Hospital Herlev, Herlev Ringvej, DK-2730 Herlev (Denmark); Department of Diagnostic Sciences, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3C, DK-2200 Copenhagen (Denmark); Andersen, L.P.H.; Klein, M. [Department of Surgical Gastroenterology D, Copenhagen University Hospital Herlev, Herlev Ringvej, DK-2730 Herlev (Denmark); Department of Diagnostic Sciences, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3C, DK-2200 Copenhagen (Denmark); Logager, V.; Chabanova, E.; Thomsen, H.S. [Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev Ringvej, DK-2730 Herlev (Denmark); Department of Diagnostic Sciences, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3C, DK-2200 Copenhagen (Denmark); Rosenberg, J. [Department of Surgical Gastroenterology D, Copenhagen University Hospital Herlev, Herlev Ringvej, DK-2730 Herlev (Denmark); Department of Diagnostic Sciences, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3C, DK-2200 Copenhagen (Denmark)

2010-06-15

Background: Colorectal cancer will present itself as a bowel obstruction in 16-23% of all cases. However, not all obstructing tumors are malignant and the differentiation between a benign and a malignant tumor can be difficult. The purpose of our study was to determine whether fast dynamic gadolinium-enhanced MR imaging combined with MR colonography could be used to differentiate a benign from a malignant obstructing colon tumor. Methods: Patients with benign colon tumor stenosis, based on diverticulitis, were asked to participate in the study. The same number of patients with verified colorectal cancer was included. Both groups had to be scheduled for surgery to be included. Two blinded observers analyzed the tumors on MR by placing a region of interest in the tumor and a series of parameters were evaluated, e.g. wash-in, wash-out and time-to-peak. Results: 14 patients were included. The wash-in and wash-out rates were significantly different between the benign and malignant tumors, and a clear distinction between benign and malignant disease was therefore possible by looking only at the MR data. Furthermore, MR colography evaluating the rest of the colon past the stenosis was possible with all patients. Conclusion: The results showed the feasibility of using fast dynamic gadolinium-enhanced MR imaging to differentiate between benign and malignant colonic tumors. With a high intra-class correlation and significant differences found on independent segments of the tumor, the method appears to be reproducible. Furthermore, the potential is big in performing a full preoperative colon evaluation even in patients with obstructing cancer. Trial number: (NCT00114829).

Optimization of Protocol CT, PET-CT, whole body

International Nuclear Information System (INIS)

Gutierrez, Fredys Santos; Namias, Mauro

2013-01-01

The objective of this study was to optimize the acquisition protocols and processing existing of the CT PET/CT scanner for clinical use of Nuclear Diagnostic Center Foundation, a way to minimize the radiation dose while maintaining diagnostic image quality properly. Dosimetric data of PET / CT service were surveyed and obtained the baseline against which we compare and define strategies and modifications to develop online. We selected transaxial up to the pulmonary hilum and liver slices as the anatomical regions of interest that led to the standardization of the study

Computed Tomography (CT) -- Head

Medline Plus

Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray ... What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT ...

Usefulness of multi-plane dynamic subtraction CT (MPDS-CT) for intracranial high density lesions

Energy Technology Data Exchange (ETDEWEB)

Takagi, Ryo; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan)

1996-02-01

We present a new CT technique using the high speed CT scanner in detection and evaluation of temporal and spatial contrast enhancement of intracranial high density lesions. A multi-plane dynamic subtraction CT (MPDS-CT) was performed in 21 patients with intracranial high density lesions. These lesions consisted of 10 brain tumors, 7 intracerebral hemorrhages and 4 vascular malformations (2 untreated, 2 post-embolization). Baseline study was first performed, and 5 sequential planes of covering total high density lesions were selected. After obtaining the 5 sequential CT images as mask images, three series of multi-plane dynamic CT were performed for the same 5 planes with an intravenous bolus injection of contrast medium. MPDS-CT images were reconstructed by subtracting dynamic CT images from the mask ones. MPDS-CT were compared with conventional contrast-enhanced CT. MPDS-CT images showed the definite contrast enhancement of high density brain tumors and vascular malformations which were not clearly identified on conventional contrast-enhanced CT images because of calcified or hemorrhagic lesions and embolic materials, enabling us to eliminate enhanced abnormalities with non-enhanced areas such as unusual intracerebral hemorrhages. MPDS-CT will provide us further accurate and objective information and will be greatly helpful for interpreting pathophysiologic condition. (author).

Abdominal and Pelvic CT

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Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Abdomen and Pelvis Computed tomography (CT) of the abdomen and pelvis is a ... is CT Scanning of the Abdomen/Pelvis? Computed tomography, more commonly known as a CT or CAT ...

Radiation exposure during CT-guided biopsies: recent CT machines provide markedly lower doses.

Science.gov (United States)

Guberina, Nika; Forsting, Michael; Ringelstein, Adrian; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Theysohn, Jens; Wetter, Axel

2018-03-28

To examine radiation dose levels of CT-guided interventional procedures of chest, abdomen, spine and extremities on different CT-scanner generations at a large multicentre institute. 1,219 CT-guided interventional biopsies of different organ regions ((A) abdomen (n=516), (B) chest (n=528), (C) spine (n=134) and (D) extremities (n=41)) on different CT-scanners ((I) SOMATOM-Definition-AS+, (II) Volume-Zoom, (III) Emotion6) were included from 2013-2016. Important CT-parameters and standard dose-descriptors were retrospectively examined. Additionally, effective dose and organ doses were calculated using Monte-Carlo simulation, following ICRP103. Overall, radiation doses for CT interventions are highly dependent on CT-scanner generation: the newer the CT scanner, the lower the radiation dose imparted to patients. Mean effective doses for each of four procedures on available scanners are: (A) (I) 9.3mSv versus (II) 13.9mSv (B) (I) 7.3mSv versus (III) 11.4mSv (C) (I) 6.3mSv versus (II) 7.4mSv (D) (I) 4.3mSv versus (II) 10.8mSv. Standard dose descriptors [standard deviation (SD); CT dose index vol (CTDI vol ); dose-length product (DLP body ); size-specific dose estimate (SSDE)] were also compared. Effective dose, organ doses and SSDE for various CT-guided interventional biopsies on different CT-scanner generations following recommendations of the ICRP103 are provided. New CT-scanner generations involve markedly lower radiation doses versus older devices. • Effective dose, organ dose and SSDE are provided for CT-guided interventional examinations. • These data allow identifying organs at risk of higher radiation dose. • Detailed knowledge of radiation dose may contribute to a better individual risk-stratification. • New CT-scanner generations involve markedly lower radiation doses compared to older devices.

Diagnosis of tracheal instability: inspiratory and expiratory spiral CT and cine CT

International Nuclear Information System (INIS)

Heussel, C.P.; Thelen, M.; Kauczor, H.U.; Hafner, B.; Lill, J.

2000-01-01

Purpose: In tracheo- and bronchomalacia, localization and determination of collapse is necessary for planning a surgical procedure. We compared inspiratory and spiral CT, cine CT, and bronchoscopy and evaluated the relevance of each method. Methods: Seventeen patients with suspected or verified tracheal stonosis or collapse underwent paired inspiratory and exspiratory spiral CT and cine CT during continuous respiration (temporal increment 100 ms). The tracheal cross-sectional area was calculated and compared. Results: In addition to bronchoscopy, further information concerning localization, extent, collapse, stability of the tracheal wall, distal portions of the stenosis, and extraluminal compressions was obtained. A significantly higher degree of tracheal collapse was seen using cine CT compared to paired spiral CT (p [de

Implications of CT noise and artifacts for quantitative 99mTc SPECT/CT imaging

International Nuclear Information System (INIS)

Hulme, K. W.; Kappadath, S. C.

2014-01-01

Purpose: This paper evaluates the effects of computed tomography (CT) image noise and artifacts on quantitative single-photon emission computed-tomography (SPECT) imaging, with the aim of establishing an appropriate range of CT acquisition parameters for low-dose protocols with respect to accurate SPECT attenuation correction (AC). Methods: SPECT images of two geometric and one anthropomorphic phantom were reconstructed iteratively using CT scans acquired at a range of dose levels (CTDI vol = 0.4 to 46 mGy). Resultant SPECT image quality was evaluated by comparing mean signal, background noise, and artifacts to SPECT images reconstructed using the highest dose CT for AC. Noise injection was performed on linear-attenuation (μ) maps to determine the CT noise threshold for accurate AC. Results: High levels of CT noise (σ ∼ 200–400 HU) resulted in low μ-maps noise (σ ∼ 1%–3%). Noise levels greater than ∼10% in 140 keV μ-maps were required to produce visibly perceptible increases of ∼15% in 99m Tc SPECT images. These noise levels would be achieved at low CT dose levels (CTDI vol = 4 μGy) that are over 2 orders of magnitude lower than the minimum dose for diagnostic CT scanners. CT noise could also lower (bias) the expected μ values. The relative error in reconstructed SPECT signal trended linearly with the relative shift in μ. SPECT signal was, on average, underestimated in regions corresponding with beam-hardening artifacts in CT images. Any process that has the potential to change the CT number of a region by ∼100 HU (e.g., misregistration between CT images and SPECT images due to motion, the presence of contrast in CT images) could introduce errors in μ 140 keV on the order of 10%, that in turn, could introduce errors on the order of ∼10% into the reconstructed 99m Tc SPECT image. Conclusions: The impact of CT noise on SPECT noise was demonstrated to be negligible for clinically achievable CT parameters. Because CT dose levels that affect

Performance evaluation of the General Electric eXplore CT 120 micro-CT using the vmCT phantom

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Bahri, M.A., E-mail: M.Bahri@ulg.ac.be [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); Warnock, G.; Plenevaux, A. [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); Choquet, P.; Constantinesco, A. [Biophysique et Medecine Nucleaire, Hopitaux universitaires de Strasbourg, Strasbourg (France); Salmon, E.; Luxen, A. [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); Seret, A. [ULg-Liege University, Cyclotron Research Centre, Liege, Bat. 30, Allee du 6 aout, 8 (Belgium); ULg-Liege University, Experimental Medical Imaging, Liege (Belgium)

2011-08-21

The eXplore CT 120 is the latest generation micro-CT from General Electric. It is equipped with a high-power tube and a flat-panel detector. It allows high resolution and high contrast fast CT scanning of small animals. The aim of this study was to compare the performance of the eXplore CT 120 with that of the eXplore Ultra, its predecessor for which the methodology using the vmCT phantom has already been described . The phantom was imaged using typical a rat (fast scan or F) or mouse (in vivo bone scan or H) scanning protocols. With the slanted edge method, a 10% modulation transfer function (MTF) was observed at 4.4 (F) and 3.9-4.4 (H) mm{sup -1} corresponding to 114 {mu}m resolution. A fairly larger MTF was obtained by the coil method with the MTF for the thinnest coil (3.3 mm{sup -1}) equal to 0.32 (F) and 0.34 (H). The geometric accuracy was better than 0.3%. There was a highly linear (R{sup 2}>0.999) relationship between measured and expected CT numbers for both the CT number accuracy and linearity sections of the phantom. A cupping effect was clearly seen on the uniform slices and the uniformity-to-noise ratio ranged from 0.52 (F) to 0.89 (H). The air CT number depended on the amount of polycarbonate surrounding the area where it was measured; a difference as high as approximately 200 HU was observed. This hindered the calibration of this scanner in HU. This is likely due to the absence of corrections for beam hardening and scatter in the reconstruction software. However in view of the high linearity of the system, the implementation of these corrections would allow a good quality calibration of the scanner in HU. In conclusion, the eXplore CT 120 achieved a better spatial resolution than the eXplore Ultra (based on previously reported specifications) and future software developments will include beam hardening and scatter corrections that will make the new generation CT scanner even more promising.

Pediatric CT angiography

International Nuclear Information System (INIS)

Siegel, M.J.

2005-01-01

Advances in CT technology are having profound impact on imaging children and have made CT angiography possible even in neonates. Even with the tiny anatomy of neonates, small volumes of contrast material, and small venous access catheters, successful CT angiography can be performed with attention to detail. Meticulous attention to patient preparation, the proper selection of technical factors, and optimal delivery of contrast material are crucial. Data post-processing and the creation of 3-D reconstructions are also essential in establishing a correct diagnosis. The applications fo CT angiography are different in children than in adults and most applications in children involve assessment of congenital and postoperative vascular and cardiac diseases. The use of CT angiography offers the opportunity to eliminate the long periods of sedation associated with MR and reduce the radiation exposure associated with conventional angiography. Generally, the benefits of CT angiography in children outweigh the risk, namely that of radiation exposure. However, care must still be taken to minimize the radiation exposure. (orig.)

Preoperative 4D CT Localization of Nonlocalizing Parathyroid Adenomas by Ultrasound and SPECT-CT.

Science.gov (United States)

Hinson, Andrew M; Lee, David R; Hobbs, Bradley A; Fitzgerald, Ryan T; Bodenner, Donald L; Stack, Brendan C

2015-11-01

To evaluate 4-dimensional (4D) computed tomography (CT) for the localization of parathyroid adenomas previously considered nonlocalizing on ultrasound and single-photon emission CT with CT scanning (SPECT-CT). To measure radiation exposure associated with 4D-CT and compared it with SPECT-CT. Case series with chart review. University tertiary hospital. Nineteen adults with primary hyperparathyroidism who underwent preoperative 4D CT from November 2013 through July 2014 after nonlocalizing preoperative ultrasound and technetium-99m SPECT-CT scans. Sensitivity, specificity, predictive values, and accuracy of 4D CT were evaluated. Nineteen patients (16 women and 3 men) were included with a mean age of 66 years (range, 39-80 years). Mean preoperative parathyroid hormone level was 108.5 pg/mL (range, 59.3-220.9 pg/mL), and mean weight of the excised gland was 350 mg (range, 83-797 mg). 4D CT sensitivity and specificity for localization to the patient's correct side of the neck were 84.2% and 81.8%, respectively; accuracy was 82.9%. The sensitivity for localizing adenomas to the correct quadrant was 76.5% and 91.5%, respectively; accuracy was 88.2%. 4D CT radiation exposure was significantly less than the radiation associated with SPECT-CT (13.8 vs 18.4 mSv, P = 0.04). 4D CT localizes parathyroid adenomas with relatively high sensitivity and specificity and allows for the localization of some adenomas not observed on other sestamibi-based scans. 4D CT was also associated with less radiation exposure when compared with SPECT-CT based on our study protocol. 4D CT may be considered as first- or second-line imaging for localizing parathyroid adenomas in the setting of primary hyperparathyroidism. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Coronary CT angiography

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Dewey, Marc [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie

2009-07-01

Coronary CT angiography has attained increasing scientific attention at academic institutions and has become a highly accurate diagnostic modality. Extending this knowledge into a practice setting is the purpose of 'Coronary CT Angiography'. This book will assist you in integrating cardiac CT into your daily practice, while also giving an overview of the current technical status and applications. The specific features of scanners from all four main vendors are also presented providing an objective overview of noninvasive coronary angiography using CT. (orig.)

Indications for chest CT. Retrospective study of cases with normal chest CT

International Nuclear Information System (INIS)

Obata, Shiro

1995-01-01

The usefulness of computed tomography (CT) in thoracic radiology is now well appreciated, and the number of chest CTs has greatly increased. There are, however, many chest CT cases that are completely or almost completely normal. Indications for chest CT should be re-evaluated considering the cost and radiation exposure associated with the examination. Reviewing the reports of 4930 chest CT examinations performed in three hospitals during the period of two years, the author found 620 (12.6%) negative CT examinations. In 312 of the 620, the CT was requested because of 'abnormal shadow' on chest radiograph. When the same chest radiographs were re-evaluated by two radiologists, no abnormality was noted in 257 cases (82.4%). CT examinations were considered justified in only 55 cases (17.6%). There was a significant difference in the frequency of normal chest CT examinations between the university hospital and two other hospitals. The causes of false positive interpretation of chest radiographs were analyzed, and it was felt that fundamental knowledge necessary to interpret chest radiographs was lacking. The importance of close cooperation between clinicians and radiologists should be emphasized. (author)

Micro-CT and nano-CT analysis of filling quality of three different endodontic sealers.

Science.gov (United States)

Huang, Yan; Celikten, Berkan; de Faria Vasconcelos, Karla; Ferreira Pinheiro Nicolielo, Laura; Lippiatt, Nicholas; Buyuksungur, Arda; Jacobs, Reinhilde; Orhan, Kaan

2017-12-01

To investigate voids in different root canal sealers using micro-CT and nano-CT, and to explore the feasibility of using nano-CT for quantitative analysis of sealer filling quality. 30 extracted mandibular central incisors were randomly assigned into three groups according to the applied root canal sealers (Total BC Sealer, Sure Seal Root, AH Plus) by the single cone technique. Subsequently, micro-CT and nano-CT were performed to analyse the incidence rate of voids, void fraction, void volume and their distribution in each sample. Micro-CT evaluation showed no significant difference among sealers for the incidence rate of voids or void fraction in the whole filling materials (p > 0.05), whereas a significant difference was found between AH Plus and the other two sealers using nano-CT (p nano-CT results displayed higher void volume in AH Plus among all the sealers and regions (p nano-CT analysis, when round root canals were treated by the single cone technique. The disparate results suggest that the higher resolution of nano-CT have a greater ability of distinguishing internal porosity, and therefore suggesting the potential use of nano-CT in quantitative analysis of filling quality of sealers.

Xenon-enhanced CT using subtraction CT: Basic and preliminary clinical studies for comparison of its efficacy with that of dual-energy CT and ventilation SPECT/CT to assess regional ventilation and pulmonary functional loss in smokers

International Nuclear Information System (INIS)

Ohno, Yoshiharu; Yoshikawa, Takeshi; Takenaka, Daisuke; Fujisawa, Yasuko; Sugihara, Naoki; Kishida, Yuji; Seki, Shinichiro; Koyama, Hisanobu; Sugimura, Kazuro

2017-01-01

Purpose: To prospectively and directly compare the capability for assessments of regional ventilation and pulmonary functional loss in smokers of xenon-ventilation CT obtained with the dual-energy CT (DE-CT) and subtraction CT (Sub-CT) Materials and methods: Twenty-three consecutive smokers (15 men and 8 women, mean age: 69.7 ± 8.7 years) underwent prospective unenhanced and xenon-enhanced CTs, the latter by Sub-CT and DE-CT methods, ventilation SPECT and pulmonary function tests. Sub-CT was generated from unenhanced and xenon-enhanced CT, and all co-registered SPECT/CT data were produced from SPECT and unenhanced CT data. For each method, regional ventilation was assessed by using a 11-point scoring system on a per-lobe basis. To determine the functional lung volume by each method, it was also calculated for individual sublets with a previously reported method. To determine inter-observer agreement for each method, ventilation defect assessment was evaluated by using the χ2 test with weighted kappa statistics. For evaluation of the efficacy of each method for pulmonary functional loss assessment, functional lung volume was correlated with%FEV 1 . Results: Each inter-observer agreement was rated as substantial (Sub-CT: κ = 0.69, p < 0.0001; DE-CT: κ = 0.64, p < 0.0001; SPECT/CT: κ = 0.64, p < 0.0001). Functional lung volume for each method showed significant to good correlation with%FEV 1 (Sub-CT: r = 0.72, p = 0.0001; DE-CT: r = 0.74, p < 0.0001; SPECT/CT: r = 0.66, p = 0.0006). Conclusion: Xenon-enhanced CT obtained by Sub-CT can be considered at least as efficacious as that obtained by DE-CT and SPECT/CT for assessment of ventilation abnormality and pulmonary functional loss in smokers.

Xenon-enhanced CT using subtraction CT: Basic and preliminary clinical studies for comparison of its efficacy with that of dual-energy CT and ventilation SPECT/CT to assess regional ventilation and pulmonary functional loss in smokers

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Ohno, Yoshiharu, E-mail: yosirad@kobe-u.ac.jp [Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe (Japan); Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe (Japan); Yoshikawa, Takeshi [Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe (Japan); Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe (Japan); Takenaka, Daisuke [Department of Radiology, Hyogo Cancer Center, Akashi (Japan); Fujisawa, Yasuko; Sugihara, Naoki [Toshiba Medical Systems Corporation, Otawara (Japan); Kishida, Yuji; Seki, Shinichiro; Koyama, Hisanobu; Sugimura, Kazuro [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine (Japan)

2017-01-15

Purpose: To prospectively and directly compare the capability for assessments of regional ventilation and pulmonary functional loss in smokers of xenon-ventilation CT obtained with the dual-energy CT (DE-CT) and subtraction CT (Sub-CT) Materials and methods: Twenty-three consecutive smokers (15 men and 8 women, mean age: 69.7 ± 8.7 years) underwent prospective unenhanced and xenon-enhanced CTs, the latter by Sub-CT and DE-CT methods, ventilation SPECT and pulmonary function tests. Sub-CT was generated from unenhanced and xenon-enhanced CT, and all co-registered SPECT/CT data were produced from SPECT and unenhanced CT data. For each method, regional ventilation was assessed by using a 11-point scoring system on a per-lobe basis. To determine the functional lung volume by each method, it was also calculated for individual sublets with a previously reported method. To determine inter-observer agreement for each method, ventilation defect assessment was evaluated by using the χ2 test with weighted kappa statistics. For evaluation of the efficacy of each method for pulmonary functional loss assessment, functional lung volume was correlated with%FEV{sub 1}. Results: Each inter-observer agreement was rated as substantial (Sub-CT: κ = 0.69, p < 0.0001; DE-CT: κ = 0.64, p < 0.0001; SPECT/CT: κ = 0.64, p < 0.0001). Functional lung volume for each method showed significant to good correlation with%FEV{sub 1} (Sub-CT: r = 0.72, p = 0.0001; DE-CT: r = 0.74, p < 0.0001; SPECT/CT: r = 0.66, p = 0.0006). Conclusion: Xenon-enhanced CT obtained by Sub-CT can be considered at least as efficacious as that obtained by DE-CT and SPECT/CT for assessment of ventilation abnormality and pulmonary functional loss in smokers.

Non-enhanced CT versus contrast-enhanced CT in integrated PET/CT studies for nodal staging of rectal cancer

International Nuclear Information System (INIS)

Tateishi, Ukihide; Maeda, Tetsuo; Morimoto, Tsuyoshi; Miyake, Mototaka; Arai, Yasuaki; Kim, E.E.

2007-01-01

The purpose of the present study was to determine the diagnostic accuracy of non-enhanced CT and contrast-enhanced CT in integrated PET/CT studies for preoperative nodal staging of rectal cancer. Retrospective analysis was performed in 53 patients with pathologically proven rectal cancer who had been referred for preoperative staging. All patients underwent integrated PET/CT consisting of non-enhanced and contrast-enhanced CT followed by whole-body fluorine-18-fluorodeoxyglucose ([ 18 F]FDG) PET. Both non-enhanced and contrast-enhanced PET/CT images were evaluated separately by two observers in consensus. The reference standard was histopathologic results. For nodal staging of rectal cancer, we compared diagnostic accuracy on a per-patient basis between the two modalities. Nodal staging was correctly determined with non-enhanced studies in 37 patients (70%) and with contrast-enhanced studies in 42 patients (79%). On a per-patient basis, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of regional lymph node staging were 85%, 68%, 83%, 72%, and 79%, respectively, with contrast-enhanced studies, and 85%, 42%, 73%, 62%, and 70%, respectively, with non-enhanced studies. The difference in the accuracy of nodal staging between the two modalities was not significant (p = 0.063). Compared with non-enhanced studies, contrast-enhanced studies determined more correctly the status of pararectal lymph nodes (p 0.002), internal iliac lymph nodes (p = 0.004), and obturator lymph nodes (p < 0.0001). Contrast-enhanced PET/CT is superior to non-enhanced PET/CT for precise definition of regional nodal status in rectal cancer. (orig.)

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses ... of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses special ... the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

Perfusion CT in acute stroke

International Nuclear Information System (INIS)

Eckert, Bernd; Roether, Joachim; Fiehler, Jens; Thomalla, Goetz

2015-01-01

Modern multislice CT scanners enable multimodal protocols including non-enhanced CT, CT angiography, and CT perfusion. A 64-slice CT scanner provides 4-cm coverage. To cover the whole brain, a 128 - 256-slice scanner is needed. The use of perfusion CT requires an optimized scan protocol in order to reduce exposure to radiation. As compared to non-enhanced CT and CT angiography, the use of CT perfusion increases detection rates of cerebral ischemia, especially small cortical ischemic lesions, while the detection of lacunar and infratentorial stroke lesions remains limited. Perfusion CT enables estimation of collateral flow in acute occlusion of large intra- or extracranial arteries. Currently, no established reliable thresholds are available for determining infarct core and penumbral tissue by CT perfusion. Moreover, perfusion parameters depend on the processing algorithms and the software used for calculation. However, a number of studies point towards a reduction of cerebral blood volume (CBV) below 2 ml/100 g as a critical threshold that identifies infarct core. Large CBV lesions are associated with poor outcome even in the context of recanalization. The extent of early ischemic signs on non-enhanced CT remains the main parameter from CT imaging to guide acute reperfusion treatment. Nevertheless, perfusion CT increases diagnostic and therapeutic certainty in the acute setting. Similar to stroke MRI, perfusion CT enables the identification of tissue at risk of infarction by the mismatch between infarct core and the larger area of critical hypoperfusion. Further insights into the validity of perfusion parameters are expected from ongoing trials of mechanical thrombectomy in stroke.

Spiral CT versus conventional CT in the preoperative assessment of metallic intraocular foreign bodies

International Nuclear Information System (INIS)

Prokesch, R.; Bankier, A.; Ba-Ssalamah, A.; Imhof, H.; Lakits, A.; Scholda, C.

1998-01-01

Purpose: To compare the effectiveness of spiral CT versus conventional CT in the preoperative assessment of metallic intraocular foreign bodies. Results: All foreign bodies were detected by each scanning modality on the axial and on the reconstructed planes. The quality of the axial images was similar for spiral and conventional CT. The spiral technique provided high-quality reconstructed images which allowed accurate localization of the foreign bodies in all cases. Reconstructions by conventional technique were inadequate for preoperative assessment. The examination time for the total orbital volume was 18 s for spiral CT and 52 s for conventional CT. Radiation dose delivered to the lens was 35 mGy for spiral CT and 56 mGy for conventional CT axial scanning. Conclusion: Spiral CT multiplanar offers several significant advantages for the preoperative assessment of metallic intraocular foreign bodies compared to the conventional CT technique in clinical practice, including short examination time, minimized motion artifacts, reduced radiation exposure, and accurate localization. (orig.) [de

CT and MR imaging of the kidney and adrenal glands: CT of the kidney

International Nuclear Information System (INIS)

Levine, E.

1987-01-01

Because of its high diagnostic yield, safety, and cost-effectiveness, CT has become a major imaging technique for evaluating the kidney. CT is highly accurate for determining the nature and extent of renal masses, and this has become the main indication for renal CT. However, CT is also valuable in assessing patients with renal cystic disease, trauma, inflammatory disease, infarction, hemorrhage and hydronephrosis of unknown cause. This presentation reviews the normal CT anatomy of the kidneys and the usefulness of CT in the diagnosis of all these conditions. Examination techniques are discussed with particular emphasis on avoiding diagnostic pitfalls and tailoring the examination to the nature of the clinical problem. CT findings in various renal disorders are compared with those of other imaging techniques, particularly US and angiography, and the place of CT in the diagnostic approach to these disorders is considered

Improved attenuation correction for respiratory gated PET/CT with extended-duration cine CT: a simulation study

Science.gov (United States)

Zhang, Ruoqiao; Alessio, Adam M.; Pierce, Larry A.; Byrd, Darrin W.; Lee, Tzu-Cheng; De Man, Bruno; Kinahan, Paul E.

2017-03-01

Due to the wide variability of intra-patient respiratory motion patterns, traditional short-duration cine CT used in respiratory gated PET/CT may be insufficient to match the PET scan data, resulting in suboptimal attenuation correction that eventually compromises the PET quantitative accuracy. Thus, extending the duration of cine CT can be beneficial to address this data mismatch issue. In this work, we propose to use a long-duration cine CT for respiratory gated PET/CT, whose cine acquisition time is ten times longer than a traditional short-duration cine CT. We compare the proposed long-duration cine CT with the traditional short-duration cine CT through numerous phantom simulations with 11 respiratory traces measured during patient PET/CT scans. Experimental results show that, the long-duration cine CT reduces the motion mismatch between PET and CT by 41% and improves the overall reconstruction accuracy by 42% on average, as compared to the traditional short-duration cine CT. The long-duration cine CT also reduces artifacts in PET images caused by misalignment and mismatch between adjacent slices in phase-gated CT images. The improvement in motion matching between PET and CT by extending the cine duration depends on the patient, with potentially greater benefits for patients with irregular breathing patterns or larger diaphragm movements.

A modified VMAT adaptive radiotherapy for nasopharyngeal cancer patients based on CT-CT image fusion

International Nuclear Information System (INIS)

Jin, Xiance; Han, Ce; Zhou, Yongqiang; Yi, Jinling; Yan, Huawei; Xie, Congying

2013-01-01

To investigate the feasibility and benefits of a modified adaptive radiotherapy (ART) by replanning in the initial CT (iCT) with new contours from a repeat CT (rCT) based on CT-CT image fusion for nasopharyngeal cancer (NPC) patients underwent volumetric modulated arc radiotherapy (VMAT). Nine NPC patients underwent VMAT treatment with a rCT at 23rd fraction were enrolled in this study. Dosimetric differences for replanning VMAT plans in the iCT and in the rCT were compared. Volumetric and dosimetric changes of gross tumor volume (GTV) and organs at risk (OARs) of this modified ART were also investigated. No dosimetric differences between replanning in the iCT and in the rCT were observed. The average volume of GTV decreased from 78.83 ± 38.42 cm 3 in the iCT to 71.44 ± 37.46 cm 3 in the rCT, but with no significant difference (p = 0.42).The average volume of the left and right parotid decreased from 19.91 ± 4.89 cm 3 and 21.58 ± 6.16 cm 3 in the iCT to 11.80 ± 2.79 cm 3 and 13.29 ± 4.17 cm 3 in the rCT (both p < 0.01), respectively. The volume of other OARs did not shrink very much. No significant differences on PTV GTV and PTV CTV coverage were observed for replanning with this modified ART. Compared to the initial plans, the average mean dose of the left and right parotid after re-optimization were decreased by 62.5 cGy (p = 0.05) and 67.3 cGy (p = 0.02), respectively, and the V5 (the volume receiving 5 Gy) of the left and right parotids were decreased by 7.8% (p = 0.01) and 11.2% (p = 0.001), respectively. There was no significant difference on the dose delivered to other OARs. Patients with NPC undergoing VMAT have significant anatomic and dosimetric changes to parotids. Repeat CT as an anatomic changes reference and re-optimization in the iCT based on CT-CT image fusion was accurate enough to identify the volume changes and to ensure safe dose to parotids

Abdominal and Pelvic CT

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Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ...

Computed Tomography (CT) -- Sinuses

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Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ...

Computed Tomography (CT) -- Head

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Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ...

Prevalence of abdominal aortic aneurysm (AAA) in a population undergoing computed tomography colonography in Canterbury, New Zealand.

Science.gov (United States)

Khashram, M; Jones, G T; Roake, J A

2015-08-01

There is compelling level 1 evidence in support of screening men for abdominal aortic aneurysm (AAA) to reduce AAA mortality. However, New Zealand (NZ) lacks data on AAA prevalence, and national screening has not been implemented. The aim of this study was to determine the prevalence of AAA in a population undergoing a computed tomography colonography (CTC) for gastrointestinal symptoms. This was an observational study; all consecutive CTCs performed in three regions of the South Island of NZ over a 4 year period were reviewed. Data on abdominal and thoracic aorta diameters ≥30 mm, and iliac and femoral aneurysms ≥20 mm were recorded. Previous aortic surgical grafts or endovascular stents were also documented. Demographics, survival, and AAA related outcomes were collected and used for analysis. Included were 4,893 scans on 4,644 patients (1,933 men [41.6%], 2,711 women [58.4%]) with a median age of 69.3 years (range 17.0-97.0 years). There were 309 scans on 289 patients (75.4% men) who had either an aneurysm or a previous aortic graft with a median age of 79.6 years (range 57.0-96.0 years). Of these, 223 had a native AAA ≥30 mm. The prevalence of AAA rose with age from 1.3% in men aged 55-64 years, to 9.1% in 65-74 year olds, 16.8% in 75-84 year olds, and 22.0% in ≥85 year olds. The corresponding figures in women were 0.4%, 2%, 3.9%, and 6.2%, respectively. In this observational study, the prevalence of AAA was high and warrants further evaluation. The results acquired help to define a population that may benefit from a national AAA screening programme. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Spiral CT for evaluation of chest trauma; Spiral-CT beim Thoraxtrauma

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Roehnert, W. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik; Weise, R. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik

1997-07-01

After implementation of spiral CT in our department, we carried out an analysis for determining anew the value of CT as a modality of chest trauma diagnosis in the emergency department. The retrospective study covers a period of 10 months and all emergency patients with chest trauma exmined by spiral CT. The major lesions of varying seriousness covered by this study are: pneumothorax, hematothorax, pulmonary contusion or laceration, mediastinal hematoma, rupture of a vessel, injury of the heart and pericardium. The various fractures are not included in this study. In many cases, spiral CT within relatively short time yields significant diagnostic findings, frequently saving additional angiography. A rigid diagnostic procedure cannot be formulated. Plain-film chest radiography still remains a diagnostic modality of high value. (Orig.) [Deutsch] Nach Einfuehrung der Spiral-CT in unserer Einrichtung versuchten wir, den Stellenwert der Computertomographie in der Notfalldiagnostik des Thoraxtraumas neu zu bestimmen. Dazu wurden retrospektiv ueber einen Zeitraum von 10 Monaten alle mittels Spiral-CT untersuchten Notfallpatienten mit Thoraxverletzungen ausgewertet. Im Vordergrund standen folgende Befunde unterschiedlichen Schweregrades: Pneumothorax, Haematothorax, Lungenkontusion/-lazeration, Mediastinalhaematom, Gefaessruptur, Herz- und Herzbeutelverletzung. Auf die unterschiedlichen Frakturen wird bewusst nicht naeher eingegangen. In vielen Faellen liefert die Spiral-CT mit relativ geringem Zeitaufwand wesentliche diagnostische Aussagen. Haeufig kann auf eine Angiographie verzichtet werden. Ein starres diagnostisches Stufenschema laesst sich nicht definieren. Die Thoraxuebersichtsaufnahme besitzt einen unveraendert hohen Stellenwert. (orig.)

Marketing cardiac CT programs.

Science.gov (United States)

Scott, Jason

2010-01-01

There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.

Postoperative CT in pancreas transplantation

International Nuclear Information System (INIS)

Powell, F.E.; Harper, S.J.F.; Callaghan, C.J.; Shaw, A.; Godfrey, E.M.; Bradley, J.A.; Watson, C.J.E.; Pettigrew, G.J.

2015-01-01

Aim: To examine the usage and value of computed tomography (CT) following simultaneous pancreas and kidney (SPK) transplantation. Materials and methods: Indications for postoperative CT, key findings, and their influence on management were determined by retrospective analysis. Results: Ninety-eight patients underwent 313 CT examinations. Common indications for the examinations included suspected intra-abdominal collection (31.1%) and elevated serum amylase/lipase (24.1%). CT findings most frequently showed non-specific mild inflammation (27.6%), a normal scan (17.1%) and fluid collections (16.3%). High capillary blood glucose (CBG) was associated with resultant CT demonstration of graft vascular abnormalities, but otherwise, particular clinical indications were not associated with specific CT findings. Conclusion: Clinical findings in patients with SPK transplants are non-specific. The pattern of abnormalities encountered is significantly different to those seen in native pancreatic disease and demands a tailored protocol. CT enables accurate depiction of vascular abnormalities and fluid collections, thus reducing the number of surgical interventions that might otherwise be required. Elevated CBG should prompt urgent CT to exclude potentially reversible vascular complications. - Highlights: • The value of CT following simultaneous pancreas and kidney transplantation was assessed. • 313 CT scans were performed on 98 patients between January 2005 and August 2010. • Elevated blood glucose was associated with CT findings of graft vascular anomalities. • CT was particularly useful in directing operative versus non-operative intervention.

Dark-lumen MR colonography with fecal tagging: a comparison of water enema and air methods of colonic distension for detecting colonic neoplasms

International Nuclear Information System (INIS)

Rodriguez Gomez, Sonia; Pages Llinas, Mario; Juan Garcia, Carmen de; Rimola Gibert, Jordi; Ayuso Colella, Juan R.; Ayuso Colella, Carmen; Castells Garangou, Antoni; Bordas Alsina, Josep M.

2008-01-01

The purpose was to evaluate MR colonography (MRC) with barium fecal tagging in detecting colorectal pathology and to determine how air-based and water-based colonic distension influences MRC. We studied 83 patients with high risk of colonic neoplasms. All received oral barium sulfate for colonic preparation before unenhanced and enhanced T1-weighted gradient-echo MRC using either water (n=54) or air (n=29) for colonic distension. Fecal tagging, distension, and artifacts were recorded. All patients underwent conventional colonoscopy within 2 weeks of MRC; the techniques were compared for detection of malignant neoplasms and polyps ≥1 cm, 6-9 mm, and ≤5 mm. Fecal tagging was ''good'' in 76% of the colonic segments in water-distended patients and 46% of air-distended patients. The degree of distension was ''good'' in 90.7% of water-distended patients and 44% of air-distended patients. Severe artifacts were present in 15% air-distended patients and 0.3% of water-distended patients. Both water-distended and air-distended MRC detected all malignant neoplasms and polyps ≥1 cm, but more air-distended MRC were excluded for poor quality. MRC with fecal tagging is useful for detecting lesions ≥1 cm. Air distension was inferior to water distension in most aspects. Water-based colonic distension should be used for barium-tagging MRC. (orig.)

Clinical indications for computed tomographic colonography: European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline

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Spada, Cristiano; Barbaro, Federico; Petruzziello, Lucio [Catholic University, Digestive Endoscopy Unit, Rome (Italy); Stoker, Jaap; Haan, Margriet C. de [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); Alarcon, Onofre [Universidad de La Laguna, Department of Gastroenterology, Hospital Universitario de Canarias, Facultad de Medicina, La Laguna, Tenerife (Spain); Bellini, Davide; Laghi, Andrea [Sapienza University of Rome, I.C.O.T. Hospital, Department of Radiological Sciences, Oncology and Pathology, Latina (Italy); Bretthauer, Michael [Oslo University Hospital, Department of Health Economy and Health Management, University of Oslo, and Department of Transplantation Medicine, Gastroenterology Unit, Oslo (Norway); Dumonceau, Jean-Marc [Gedyt Endoscopy Center, Buenos Aires (Argentina); Ferlitsch, Monika [Medical University of Vienna, Department of Internal Medicine III, Division of Gastroenterology and Hepatology, Vienna (Austria); Halligan, Steve; Helbren, Emma; Plumb, Andrew; Taylor, Stuart A. [University College London, Centre for Medical Imaging, London (United Kingdom); Hellstrom, Mikael [Sahlgrenska University Hospital and Sahlgrenska Academy at University of Gothenburg, Department of Radiology, Gothenburg (Sweden); Kuipers, Ernst J. [Erasmus MC University Medical Center, Department of Gastroenterology and Hepatology, Rotterdam (Netherlands); Lefere, Philippe [Virtual Colonoscopy Teaching Centre, Hooglede (Belgium); AZ Delta, Roeselare (Belgium); Mang, Thomas [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Neri, Emanuele [University of Pisa, Diagnostic and Interventional Radiology, Pisa (Italy); Regge, Daniele [Institute for Cancer Research and Treatment, Candiolo-Torino (Italy); Hassan, Cesare [Catholic University, Digestive Endoscopy Unit, Rome (Italy); Ospedale Nuovo Regina Margherita, Department of Gastroenterology, Rome (Italy)

2014-10-03

Colorectal cancer (CRC) is a major cause of morbidity and mortality [1, 2]. CRC screening by fecal occult blood testing (FOBT) has been shown to reduce CRC mortality [3, 4], and is currently used in several European countries. Colonoscopy is highly effective for detecting advanced neoplasia, and endoscopic polypectomy reduces subsequent CRCspecific incidence and mortality [5]. In Europe, colonoscopy is mainly used to investigate FOBT-positive or symptomatic patients, or as a preventive strategy in those with increased CRC risk [6]. Computed tomographic colonography (CTC) is a minimally invasive imaging technique that is highly accurate for detecting colorectal cancer (CRC) and adenomatous polyps. The technique is standardized [7], and CTC is more easily performed than barium enema. Evidence-based data suggest that CTC is the natural replacement for barium enema and a complementary rather than an alternative examination to colonoscopy. However, the clinical scenarios for which CTC is indicated remain unclear. To address this uncertainty - 20 years after the first presentation of CTC at a radiological meeting [8] - the European Society of Gastrointestinal Endoscopy (ESGE) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) decided to produce a common guideline regarding indications for CTC in clinical practice. Technical and quality issues of CTC have been deliberately excluded from this work as these have already been discussed separately [7].

Clinical indications for computed tomographic colonography: European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline

International Nuclear Information System (INIS)

Spada, Cristiano; Barbaro, Federico; Petruzziello, Lucio; Stoker, Jaap; Haan, Margriet C. de; Alarcon, Onofre; Bellini, Davide; Laghi, Andrea; Bretthauer, Michael; Dumonceau, Jean-Marc; Ferlitsch, Monika; Halligan, Steve; Helbren, Emma; Plumb, Andrew; Taylor, Stuart A.; Hellstrom, Mikael; Kuipers, Ernst J.; Lefere, Philippe; Mang, Thomas; Neri, Emanuele; Regge, Daniele; Hassan, Cesare

2015-01-01

Colorectal cancer (CRC) is a major cause of morbidity and mortality [1, 2]. CRC screening by fecal occult blood testing (FOBT) has been shown to reduce CRC mortality [3, 4], and is currently used in several European countries. Colonoscopy is highly effective for detecting advanced neoplasia, and endoscopic polypectomy reduces subsequent CRCspecific incidence and mortality [5]. In Europe, colonoscopy is mainly used to investigate FOBT-positive or symptomatic patients, or as a preventive strategy in those with increased CRC risk [6]. Computed tomographic colonography (CTC) is a minimally invasive imaging technique that is highly accurate for detecting colorectal cancer (CRC) and adenomatous polyps. The technique is standardized [7], and CTC is more easily performed than barium enema. Evidence-based data suggest that CTC is the natural replacement for barium enema and a complementary rather than an alternative examination to colonoscopy. However, the clinical scenarios for which CTC is indicated remain unclear. To address this uncertainty - 20 years after the first presentation of CTC at a radiological meeting [8] - the European Society of Gastrointestinal Endoscopy (ESGE) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) decided to produce a common guideline regarding indications for CTC in clinical practice. Technical and quality issues of CTC have been deliberately excluded from this work as these have already been discussed separately [7].

Spinal CT scan, 2

International Nuclear Information System (INIS)

Nakagawa, Hiroshi

1982-01-01

Plain CT described fairly accurately the anatomy and lesions of the lumbar and sacral spines on their transverse sections. Since hernia of the intervertebral disc could be directly diagnosed by CT, indications of myelography could be restricted. Spinal-canal stenosis of the lumbar spine occurs because of various factors, and CT not only demonstrated the accurate size and morphology of bony canals, but also elucidated thickening of the joints and yellow ligament. CT was also useful for the diagnosis of tumors in the lumbar and sacral spines, visualizing the images of bone changes and soft tissues on the trasverse sections. But the diagnosis of intradural tumors required myelography and metrizamide CT. CT has become important for the diagnosis of spinal and spinal-cord diseases and for selection of the route of surgical arrival. (Chiba, N.)

CT manifestations of liver abscess

International Nuclear Information System (INIS)

Yan Jianfeng; Peng Yongjun

2006-01-01

Objective: To study CT findings of hepatic abscess. Methods: CT findings and clinical materials of 38 patients with liver abscess verified by aspiration were retrospectively viewed. All patients were examined by non-enhanced and contrast enhanced CT. Results: In 25 cases, inhomogeneous hypodense lesions with unclear demarcation were found on non-enhanced CT. On contrast enhanced CT scan, target or cluster enhancement was found Additionally, air was found within some lesions. In the rest 13 cases with early stage liver abscess, no typical sign was found on non-enhanced CT, while rosette sign and continued enhancement sign were demonstrated after the contrast agent was given. Conclusion: Various CT findings are found in different stages of liver abscess. The diagnosis and differential diagnosis should be based on CT manifestations and clinical history as well. (authors)

Radiation exposure during paediatric CT in Sudan: CT dose, organ and effective doses

International Nuclear Information System (INIS)

Suliman, I.I.; Khamis, H.M.; Ombada, T.H.; Alzimami, K.; Alkhorayef, M.; Sulieman, A.

2015-01-01

The purpose of this study was to assess the magnitude of radiation exposure during paediatric CT in Sudanese hospitals. Doses were determined from CT acquisition parameters using CT-Expo 2.1 dosimetry software. Doses were evaluated for three patient ages (0-1, 1-5 and 5-10 y) and two common procedures (head and abdomen). For children aged 0-1 y, volume CT air kerma index (C vol ), air Kerma-length product and effective dose (E) values were 19.1 mGy, 265 mGy.cm and 3.1 mSv, respectively, at head CT and those at abdominal CT were 8.8 mGy, 242 mGy.cm and 7.7 mSv, respectively. Those for children aged 1-5 y were 22.5 mGy, 305 mGy.cm and 1.1 mSv, respectively, at head CT and 12.6 mGy, 317 mGy.cm, and 5.1 mSv, respectively, at abdominal CT. Dose values and variations were comparable with those reported in the literature. Organ equivalent doses vary from 7.5 to 11.6 mSv for testes, from 9.0 to 10.0 mSv for ovaries and from 11.1 to 14.3 mSv for uterus in abdominal CT. The results are useful for dose optimisation and derivation of national diagnostic reference levels. (authors)

CT of the knee

International Nuclear Information System (INIS)

Ghelman, B.

1987-01-01

CT can be combined with arthrography of the knee to study the following abnormalities: meniscal tears and cysts, synovial plicae, chondromalacia patellae, and osteochondritis dissecans. The CT-arthrogram images present abnormalities in a manner that resembles the ''in situ'' surgical findings, allowing management decisions to be made with greater confidence. The CT techniques for imaging the knee after arthrography are discussed, as is the use of plain CT

Computed Tomography (CT) -- Sinuses

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Full Text Available ... are the limitations of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed ... nasal cavity by small openings. top of page What are some common uses of the procedure? CT ...

Computed Tomography (CT) -- Head

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Full Text Available ... the limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, ... than regular radiographs (x-rays). top of page What are some common uses of the procedure? CT ...

Abdominal and Pelvic CT

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Full Text Available ... scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, ... preferable over CT scanning. top of page Additional Information and Resources RTAnswers.org: Radiation Therapy for Bladder ...

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... News Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) ... are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a ...

CT after transsphenoidal surgery

International Nuclear Information System (INIS)

Tazawa, Satoru

1991-01-01

Two hundred and ten CT studies of 95 patients after transsphenoidal surgery were reviewed. Spheno-ethmoid opacificaiton, intrasellar hematoma and gas bubbles were noted within 2 weeks after surgery. Bone defect of the sellar floor and bone stent were seen on coronal scans in most cases. The packing material frequently disappeared on follow-up studies. Hormonal assessment of the functioning tumor, according to which the effect of treatment was evaluated, was correlated with CT findings. Because differentiation between postoperative changes and residual mass was difficult, there was no definite CT criteria to indicate residual functioning tumor except upward convexity of the diaphragma sellae on CT more than 3 months after surgery. Initial follow up CT study is recommended to be performed at about 3 months after surgery, at which time the immediate postoperative inflammatory changes have been disappeared. The incidence of recurrence was 3/47 (6%), which was shown on follow-up CT from 4 to 10 years after surgery. Therefore, subsequent CT study should be done in every year or two, taking the clinical symptoms and hormonal data into consideration. (author)

CT after transsphenoidal surgery

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Tazawa, Satoru [Tohoku Univ., Sendai (Japan). School of Medicine

1991-03-01

Two hundred and ten CT studies of 95 patients after transsphenoidal surgery were reviewed. Spheno-ethmoid opacificaiton, intrasellar hematoma and gas bubbles were noted within 2 weeks after surgery. Bone defect of the sellar floor and bone stent were seen on coronal scans in most cases. The packing material frequently disappeared on follow-up studies. Hormonal assessment of the functioning tumor, according to which the effect of treatment was evaluated, was correlated with CT findings. Because differentiation between postoperative changes and residual mass was difficult, there was no definite CT criteria to indicate residual functioning tumor except upward convexity of the diaphragma sellae on CT more than 3 months after surgery. Initial follow up CT study is recommended to be performed at about 3 months after surgery, at which time the immediate postoperative inflammatory changes have been disappeared. The incidence of recurrence was 3/47 (6%), which was shown on follow-up CT from 4 to 10 years after surgery. Therefore, subsequent CT study should be done in every year or two, taking the clinical symptoms and hormonal data into consideration. (author).

Indeterminate lesions on planar bone scintigraphy in lung cancer patients: SPECT, CT or SPECT-CT?

International Nuclear Information System (INIS)

Sharma, Punit; Kumar, Rakesh; Singh, Harmandeep; Bal, Chandrasekhar; Malhotra, Arun; Julka, Pramod Kumar; Thulkar, Sanjay

2012-01-01

The objective of the present study was to compare the role of single photon emission computed tomography (SPECT), computed tomography (CT) and SPECT-CT of selected volume in lung cancer patients with indeterminate lesions on planar bone scintigraphy (BS). The data of 50 lung cancer patients (53 ± 10.3 years; range 30-75; male/female 38/12) with 65 indeterminate lesions on planar BS (January 2010 to November 2010) were retrospectively evaluated. All of them underwent SPECT-CT of a selected volume. SPECT, CT and SPECT-CT images were independently evaluated by two experienced readers (experience in musculoskeletal imaging, including CT: 5 and 7 years) in separate sessions. A scoring scale of 1 to 5 was used, in which 1 is definitely metastatic, 2 is probably metastatic, 3 is indeterminate, 4 is probably benign and 5 is definitely benign. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for each modality, taking a score ≤2 as metastatic. With receiver operating characteristic (ROC) curve analysis, areas under the curve (AUC) were calculated for each modality and compared. Clinical and imaging follow-up and/or histopathology were taken as reference standard. For both readers SPECT was inferior to CT (P = 0.004, P = 0.022) and SPECT-CT (P = 0.003, P = 0.037). However, no significant difference was found between CT and SPECT-CT for reader 1 (P = 0.847) and reader 2 (P = 0.592). The findings were similar for lytic as well as sclerotic lesions. Moderate inter-observer agreement was seen for SPECT images (κ = 0.426), while almost perfect agreement was seen for CT (κ = 0.834) and SPECT-CT (κ = 0.971). CT alone and SPECT-CT are better than SPECT for accurate characterisation of indeterminate lesions on planar BS in lung cancer patients. CT alone is not inferior to SPECT-CT for this purpose and might be preferred because of shorter acquisition time and wider availability. (orig.)

Evaluation of CT in hepatocellular carcinoma

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Nakao, Norio; Miura, Yukio; Ohnishi, Mitsunori; Kamikon-ya, Norihiko; Sakamoto, Yoshisato; Miura, Takashi; Sakamoto, Kiyoshi; Takayasu, Yoshio

1985-06-01

In order to evaluate the diagnostic ability of CT in hepatocellular carcinoma, four kinds of CT images were comparatively studied by the accuracy and ROC (receiver operating characteristic) curve analysis. As a result, it was clarified that CT images were evaluated more objectively by ROC curve analysis than by accuracy. The diagnostic ability of existence and differentiation of tumor in the liver were higher in order of plain CT, contrast enhanced CT (CECT), bolus CT and CT arteriography (CTA). Therefore, in an usual CT examination intended to make differential diagnosis in space occupying liver disease, bolus CT seems to be indispensable, and also CTA is essential where diagnosis is difficult even by bolus CT.

Low-dose Dental-CT

International Nuclear Information System (INIS)

Gahleitner, A.; Imhof, H.; Homolka, P.; Fuerhauser, R.; Freudenthaler, J.; Watzek, G.

2000-01-01

Dental-CT is a relatively new, increasingly used investigation technique in dental radiology. Several authors have stated that the indication for Dental-CT has to be chosen on a strict basis, due to high dose values. This article describes the technique of performing dental-CT and calculates the effective dose based on published data and own measurements as well as the dose reduction potential to achieve an optimized protocol for Dental-CT investigations. (orig.) [de

Dose calculation with respiration-averaged CT processed from cine CT without a respiratory surrogate

International Nuclear Information System (INIS)

Riegel, Adam C.; Ahmad, Moiz; Sun Xiaojun; Pan Tinsu

2008-01-01

Dose calculation for thoracic radiotherapy is commonly performed on a free-breathing helical CT despite artifacts caused by respiratory motion. Four-dimensional computed tomography (4D-CT) is one method to incorporate motion information into the treatment planning process. Some centers now use the respiration-averaged CT (RACT), the pixel-by-pixel average of the ten phases of 4D-CT, for dose calculation. This method, while sparing the tedious task of 4D dose calculation, still requires 4D-CT technology. The authors have recently developed a means to reconstruct RACT directly from unsorted cine CT data from which 4D-CT is formed, bypassing the need for a respiratory surrogate. Using RACT from cine CT for dose calculation may be a means to incorporate motion information into dose calculation without performing 4D-CT. The purpose of this study was to determine if RACT from cine CT can be substituted for RACT from 4D-CT for the purposes of dose calculation, and if increasing the cine duration can decrease differences between the dose distributions. Cine CT data and corresponding 4D-CT simulations for 23 patients with at least two breathing cycles per cine duration were retrieved. RACT was generated four ways: First from ten phases of 4D-CT, second, from 1 breathing cycle of images, third, from 1.5 breathing cycles of images, and fourth, from 2 breathing cycles of images. The clinical treatment plan was transferred to each RACT and dose was recalculated. Dose planes were exported at orthogonal planes through the isocenter (coronal, sagittal, and transverse orientations). The resulting dose distributions were compared using the gamma (γ) index within the planning target volume (PTV). Failure criteria were set to 2%/1 mm. A follow-up study with 50 additional lung cancer patients was performed to increase sample size. The same dose recalculation and analysis was performed. In the primary patient group, 22 of 23 patients had 100% of points within the PTV pass γ criteria

CT pelvimetry

International Nuclear Information System (INIS)

Vicens, J.L.; Charles, G.; Le Berre, J.; Flageat, J.

1989-01-01

Pelvimetry aims at providing the obstetrician with information on the size and morphology of the female pelvis, thus enabling him to assess the obstetrical prognosis as accurately as possible. Computed tomography (CT) has several advantages, in particular the lower mother and fetus radiation dose. After a brief description of obstetrical anatomy, the usual CT exploration method is presented and its results are considered in terms of measurements, indices and morphological findings. If performed with a very strict exploration procedure, CT pelvimetry is a very reliable, fact and comfortable method of examination. All these advantages, combined with the minimized patient dose, should lead to an increasingly widespread use of this technique [fr

Detection of skeletal muscle metastasis: torso FDG PET-CT versus contrast-enhanced chest or abdomen CT.

Science.gov (United States)

So, Young; Yi, Jeong Geun; Song, Inyoung; Lee, Won Woo; Chung, Hyun Woo; Park, Jeong Hee; Moon, Sung Gyu

2015-07-01

Skeletal muscle metastasis (SMM) in cancer patients has not been sufficiently evaluated regarding prevalence and proper method of detection. To determine the prevalence of SMM and compare the diagnostic competencies for SMM of torso F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and contrast-enhanced chest or abdomen CT. We investigated 18,225 PET-CT studies of 6359 cancer patients performed from 2005 to 2012. The PET-CT studies describing potential SMM were retrieved and the corresponding medical records were reviewed. The gold standard for SMM was histopathologically-proven SMM or imaging study-based disease progression. The detectability of SMM was compared between PET-CT and contrast-enhanced CT. Twenty-six patients had 84 SMM lesions, representing a SMM prevalence of 0.41%. Lung cancer was the most common SMM-associated malignancy (54%) and the gluteal/pelvic girdle muscle was the most frequently involved SMM site (37%). All 84 SMM lesions were visualized on PET-CT (100%). Of these PET-CT positive 84 SMM lesions, 51 lesions were in the CT field of view (FOV) (61%), whereas 33 lesions were out of the CT FOV (39%). Among these 51 lesions, 17 lesions showed rim-enhancing nodules/masses (33%), eight lesions showed homogeneously enhancing nodules (16%), three lesions showed heterogeneously enhancing nodules (6%), and 23 SMM lesions (45%) were non-diagnostic by CT. All 51 SMM lesions within CT FOV were detected on PET-CT (100%), whereas only 28 were visualized on CT (54.9%), resulting in a significant difference (P SMM was revealed by PET-CT. The prevalence of SMM was as low as 0.41% in the current large cohort of cancer patients. Torso PET-CT was a more competent modality than contrast-enhanced CT in the detection of SMM. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

CT-based postimplant dosimetry of prostate brachytherapy. Comparison of 1-mm and 5-mm section CT

International Nuclear Information System (INIS)

Tanaka, Osamu; Hayashi, Shinya; Kanematsu, Masayuki; Matsuo, Masayuki; Hoshi, Hiroaki; Nakano, Masahiro; Maeda, Sanaho; Deguchi, Takashi; Hoshi, Hiroaki

2007-01-01

The aim of this study was to compare the outcomes between 1-mm and 5-mm section computed tomography (CT)-based postimplant dosimetry. A series of 21 consecutive patients underwent permanent prostate brachytherapy. The postimplant prostate volume was calculated using 1-mm and 5-mm section CT. One radiation oncologist contoured the prostate on CT images to obtain the reconstructed prostate volume (pVol), prostate V 100 (percent of the prostate volume receiving at least the full prescribed dose), and prostate D 90 (mean dose delivered to 90% of the prostate gland). The same radiation oncologist performed the contouring three times to evaluate intraobserver variation and subjectively scored the quality of the CT images. The mean ±1 standard deviation (SD) postimplant pVol was 20.17±6.66 cc by 1-mm section CT and 22.24±8.48 cc by 5-mm section CT; the difference in the mean values was 2.06 cc (P 100 was 80.44%±7.06% by 1-mm section CT and 77.33%±10.22% by 5-mm section CT. The mean postimplant prostate D 90 was 83.28%±10.81% by 1-mm section CT and 78.60%±15.75% by 5-mm section CT. In the evaluation of image quality, 5-mm section CT was assigned significantly higher scores than 1-mm section CT. In regard to intraobserver variation, 5-mm section CT revealed less intraobserver variation than 1-mm section CT. Our current results suggested that the outcomes of postimplant dosimetry using 1-mm section CT did not improved the results over those obtained using 5-mm section CT in terms of the quality of the CT image or reproducibility. (author)

Functional CT imaging: load-dependent visualization of the subchondral mineralization by means of CT osteoabsorptionmetry (CT-OAM); Funktionelle Computertomographie: Beanspruchungsabhaengige Darstellung der subchondralen Mineralisierung mittels CT gestuetzter Osteoabsorptiometrie (CTOAM)

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Linsenmaier, U.; Schlichtenhorst, K.; Pfeifer, K.J.; Reiser, M. [Inst. fuer Klinische Radiologie, Innenstadt, Ludwig-Maximilians-Univ. Muenchen (Germany); Kersting, S.; Putz, R.; Mueller-Gerbl, M. [Anatomische Anstalt, Ludwig-Maximilians-Univ. Muenchen (Germany)

2003-05-01

Purpose: Functional computed tomography for visualization and quantification of subchondral bone mineralization using CT osteoabsorptiometry (CT-OAM). Materials and Methods: Tarsometatarsal (TMT) and metatarsophalangeal (MTP) joints of 46 human hallux valgus (HV) specimens were examined (sagittal 1/1/1 mm) on a single slice CT scanner SCT (Somatom Plus 4, Siemens AG). Subchondral bone pixels were segmented and assigned to 10 density value groups (triangle 100 HU, range 200 - 1200 HU) the pixels using volume rendering technique (VRT). The data analysis considered the severity of HV as determined by the radiographically measured HV-angle (a.p. projection). Results: CT-OAM could generate reproducible densitograms of the distribution pattern of the subchondral bone density for all four joint surfaces (TMT and MTP joints). The bone density localization enables the assignment to different groups, showing a characteristic HV-angle-dependent distribution of the maximum bone mineralization of the load-dependent densitogram (p < 0.001). Conclusion: CT-OAM is a functional CT technique for visualizing and quantifying the distribution of the subchondral bone density, enabling a noninvasive load-dependent assessment of the joint surfaces. Load-dependent densitograms of hallux valgus specimens show a characteristic correlation with an increase of the HV-angle. (orig.) [German] Ziel: Darstellung und Quantifizierung der subchondralen Mineralisierung in Abhaengigkeit von unterschiedlichen Beanspruchungssituationen mittels funktioneller Computertomographie als CT-Osteoabsorptiometrie (CT-OAM). Methode: An 46 humanen Praeparaten mit Hallux valgus (HV) wurden exemplarisch die TMT I (Tarsometatarsal)- und MTP I (Metatarsophalangeal)-Gelenke des ersten Strahles (sagittal 1/1/1 mm) an einem Singleslice Spiral-CT (SCT, Somatom Plus 4, Siemens AG) untersucht. Der subchondrale Knochen wurde segmentiert, den Pixel wurde mittels Volume Rendering Technik (VRT) 10 Graustufenbereiche (D100 HU

FDG-PET/contrast-enhanced CT as a post-treatment tool in head and neck squamous cell carcinoma: comparison with FDG-PET/non-contrast-enhanced CT and contrast-enhanced CT

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Suenaga, Yuko; Kitajima, Kazuhiro; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Ishihara, Takeaki; Sasaki, Ryohei [Kobe University Graduate, School of Medicine, Department of Radiology, Division of Radiation Oncology, Kobe (Japan); Otsuki, Naoki; Nibu, Ken-ichi [Kobe University Graduate, School of Medicine, Department of Otolaryngology-Head and Neck Surgery, Kobe (Japan); Minamikawa, Tsutomu [Kobe University Graduate School of Medicine, Department of Oral and Maxillofacial Surgery, Kobe (Japan); Kiyota, Naomi [Kobe University Hospital, Department of Medical Oncology and Hematology, Kobe (Japan)

2016-04-15

To evaluate the accuracy of PET/CT using {sup 18}F-fluorodeoxyglucose (FDG) with IV contrast for suspected recurrent head and neck squamous cell carcinoma (HNSCC). One hundred and seventy patients previously treated for HNSCC underwent PET/CT, consisting of non-contrast-enhanced and contrast-enhanced CT, to investigate suspected recurrence. Diagnostic performance of PET/contrast-enhanced CT (PET/ceCT), PET/non-contrast-enhanced CT (PET/ncCT) and contrast-enhanced CT (ceCT) for local or regional recurrence, distant metastasis, overall recurrence and second primary cancer was evaluated. The reference standard included histopathology, treatment change and imaging follow-up. The patient-based areas under the receiver operating characteristic curves (AUC) for ceCT, PET/ncCT and PET/ceCT were 0.82, 0.96 and 0.98 for local recurrence, 0.73, 0.86 and 0.86 for regional recurrence, 0.86, 0.91 and 0.92 for distant metastasis, 0.72, 0.86 and 0.87 for overall recurrence, and 0.86, 0.89 and 0.91 for a second primary cancer. Both PET/ceCT and PET/ncCT statistically showed larger AUC than ceCT for recurrence, and the difference between PET/ceCT and PET/ncCT for local recurrence reached a significant level (p = 0.039). The accuracy of PET/ceCT for diagnosing overall recurrence was high, irrespective of the time interval after the last treatment (83.3-94.1 %). FDG-PET/CT was a more accurate HNSCC restaging tool than ceCT. The added value of ceCT at FDG-PET/CT is minimal. (orig.)

Comparison SPECT-CT with PET-CT in several applications of small-animal models

International Nuclear Information System (INIS)

Pan Yifan; Song Shaoli; Huang Gang

2009-01-01

With the development of medical science, monitoring dynamic biologic processes in small-animal models of diseases has become one of the most important approaches in medical studies. Important physiologic parameters that traditionally have been characterized by nuclear medicine imaging include blood flow, biochemical metabolism, and cellular receptors. Recently, nuclear medicine has been greatly facilitated by the newer development of dual-modality integrated imaging systems (SPECT-CT and PET-CT), which provide functional and anatomical images in the same scanning session, with the acquired images co-registered by means of the hardware. The purpose of this review is to compare SPECT-CT with PET-CT in several applications of small-animal models. Conclusicn: PET-CT for small animal modes in nledical research in the applications has great advantages, but SPECT-CT is still a very important role, and research low cost. (authors)

Improved quantitation and reproducibility in multi-PET/CT lung studies by combining CT information.

Science.gov (United States)

Holman, Beverley F; Cuplov, Vesna; Millner, Lynn; Endozo, Raymond; Maher, Toby M; Groves, Ashley M; Hutton, Brian F; Thielemans, Kris

2018-06-05

Matched attenuation maps are vital for obtaining accurate and reproducible kinetic and static parameter estimates from PET data. With increased interest in PET/CT imaging of diffuse lung diseases for assessing disease progression and treatment effectiveness, understanding the extent of the effect of respiratory motion and establishing methods for correction are becoming more important. In a previous study, we have shown that using the wrong attenuation map leads to large errors due to density mismatches in the lung, especially in dynamic PET scans. Here, we extend this work to the case where the study is sub-divided into several scans, e.g. for patient comfort, each with its own CT (cine-CT and 'snap shot' CT). A method to combine multi-CT information into a combined-CT has then been developed, which averages the CT information from each study section to produce composite CT images with the lung density more representative of that in the PET data. This combined-CT was applied to nine patients with idiopathic pulmonary fibrosis, imaged with dynamic 18 F-FDG PET/CT to determine the improvement in the precision of the parameter estimates. Using XCAT simulations, errors in the influx rate constant were found to be as high as 60% in multi-PET/CT studies. Analysis of patient data identified displacements between study sections in the time activity curves, which led to an average standard error in the estimates of the influx rate constant of 53% with conventional methods. This reduced to within 5% after use of combined-CTs for attenuation correction of the study sections. Use of combined-CTs to reconstruct the sections of a multi-PET/CT study, as opposed to using the individually acquired CTs at each study stage, produces more precise parameter estimates and may improve discrimination between diseased and normal lung.

Physics and basic technology of CT

International Nuclear Information System (INIS)

Mahesh, Mahadevappa

2017-01-01

Computed Tomography is one of the prime imaging modalities in any hospital around the globe. From its inception in 1973, CT technology have advanced leaps and bounds in medical diagnosis. Advances in X-ray tubes, detection technologies and image reconstruction methods led to the development of multiple-row detector CT (MDCT) technologies in early 2000, that has been the impetus for new fields such as Cardiovascular CT, Hybrid CT (PET-CT and SPECT-CT), CT Perfusion, Cone Beam CT, etc. It is now possible to image the entire organ (such as heart) in less than 0.3 seconds providing isotropic resolution images with high temporal resolution. With all X-ray imaging modalities, including CT, the concern is the radiation dose. Since CT procedures are one of the major imaging procedures performed in any hospital, it is important to optimize CT protocols in order to provide quality images at optimal radiation dose

SU-F-J-109: Generate Synthetic CT From Cone Beam CT for CBCT-Based Dose Calculation

Energy Technology Data Exchange (ETDEWEB)

Wang, H; Barbee, D; Wang, W; Pennell, R; Hu, K; Osterman, K [Department of Radiation Oncology, NYU Langone Medical Center, New York, NY (United States)

2016-06-15

Purpose: The use of CBCT for dose calculation is limited by its HU inaccuracy from increased scatter. This study presents a method to generate synthetic CT images from CBCT data by a probabilistic classification that may be robust to CBCT noise. The feasibility of using the synthetic CT for dose calculation is evaluated in IMRT for unilateral H&N cancer. Methods: In the training phase, a fuzzy c-means classification was performed on HU vectors (CBCT, CT) of planning CT and registered day-1 CBCT image pair. Using the resulting centroid CBCT and CT values for five classified “tissue” types, a synthetic CT for a daily CBCT was created by classifying each CBCT voxel to obtain its probability belonging to each tissue class, then assigning a CT HU with a probability-weighted summation of the classes’ CT centroids. Two synthetic CTs from a CBCT were generated: s-CT using the centroids from classification of individual patient CBCT/CT data; s2-CT using the same centroids for all patients to investigate the applicability of group-based centroids. IMRT dose calculations for five patients were performed on the synthetic CTs and compared with CT-planning doses by dose-volume statistics. Results: DVH curves of PTVs and critical organs calculated on s-CT and s2-CT agree with those from planning-CT within 3%, while doses calculated with heterogeneity off or on raw CBCT show DVH differences up to 15%. The differences in PTV D95% and spinal cord max are 0.6±0.6% and 0.6±0.3% for s-CT, and 1.6±1.7% and 1.9±1.7% for s2-CT. Gamma analysis (2%/2mm) shows 97.5±1.6% and 97.6±1.6% pass rates for using s-CTs and s2-CTs compared with CT-based doses, respectively. Conclusion: CBCT-synthesized CTs using individual or group-based centroids resulted in dose calculations that are comparable to CT-planning dose for unilateral H&N cancer. The method may provide a tool for accurate dose calculation based on daily CBCT.

SU-F-J-109: Generate Synthetic CT From Cone Beam CT for CBCT-Based Dose Calculation

International Nuclear Information System (INIS)

Wang, H; Barbee, D; Wang, W; Pennell, R; Hu, K; Osterman, K

2016-01-01

Purpose: The use of CBCT for dose calculation is limited by its HU inaccuracy from increased scatter. This study presents a method to generate synthetic CT images from CBCT data by a probabilistic classification that may be robust to CBCT noise. The feasibility of using the synthetic CT for dose calculation is evaluated in IMRT for unilateral H&N cancer. Methods: In the training phase, a fuzzy c-means classification was performed on HU vectors (CBCT, CT) of planning CT and registered day-1 CBCT image pair. Using the resulting centroid CBCT and CT values for five classified “tissue” types, a synthetic CT for a daily CBCT was created by classifying each CBCT voxel to obtain its probability belonging to each tissue class, then assigning a CT HU with a probability-weighted summation of the classes’ CT centroids. Two synthetic CTs from a CBCT were generated: s-CT using the centroids from classification of individual patient CBCT/CT data; s2-CT using the same centroids for all patients to investigate the applicability of group-based centroids. IMRT dose calculations for five patients were performed on the synthetic CTs and compared with CT-planning doses by dose-volume statistics. Results: DVH curves of PTVs and critical organs calculated on s-CT and s2-CT agree with those from planning-CT within 3%, while doses calculated with heterogeneity off or on raw CBCT show DVH differences up to 15%. The differences in PTV D95% and spinal cord max are 0.6±0.6% and 0.6±0.3% for s-CT, and 1.6±1.7% and 1.9±1.7% for s2-CT. Gamma analysis (2%/2mm) shows 97.5±1.6% and 97.6±1.6% pass rates for using s-CTs and s2-CTs compared with CT-based doses, respectively. Conclusion: CBCT-synthesized CTs using individual or group-based centroids resulted in dose calculations that are comparable to CT-planning dose for unilateral H&N cancer. The method may provide a tool for accurate dose calculation based on daily CBCT.

Computed Tomography (CT) -- Sinuses

Medline Plus

Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses uses special x-ray equipment ... story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content ...

Computed Tomography (CT) -- Head

Medline Plus

Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray equipment ... story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content ...

Abdominal and Pelvic CT

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Full Text Available ... CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT ...

Computed Tomography (CT) -- Sinuses

Medline Plus

Full Text Available ... CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT ...

Computed Tomography (CT) -- Head

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Full Text Available ... CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT ...

CT of the heart

International Nuclear Information System (INIS)

Lipton, M.J.

1986-01-01

Advances based upon the detector elements instead of X-ray film have greatly increased the power of X-ray imaging. Computed tomography (CT) creates cross sectional rather than projected images. Recently, high speed CT devices have been developed for cardiovascular studies. The Cine-CT scanner employs a scanning electron beam deflected on an extended tungsten target ring. Fast scans of 50 millisecond exposures at multiple levels can provide information concerning blood flow in vessels and tissues, myocardial wall motion, valve integrity, coronary bypass graft patency and proximal coronary artery anatomy. Cine-CT dynamic scanning can also provide volume imaging with small quantities (0.05 - 1.5 ml/kg) of contrast medium administered via peripheral vein injections. Cine-CT provides simultaneous measurements of cardiac dimensions and function and is rapidly becoming a new tool for quantitating myocardial blood flow, cardiac chamber volumes and wall mechanics. The future outlook is very promising for this three-dimensional cine-CT technique with high spatial resolution. High speed CT should provide unique diagnostic information and as the technology continues to improve at a rapid speed, this new imaging modality could be a challenge for angiography. (Auth.)

CT-docking patient stretcher

International Nuclear Information System (INIS)

Mirvis, S.E.; Owens, E.; Maslyn, J.; Rizutto, M.

1990-01-01

This paper assesses the use of a patient stretcher that directly docks to a CT scanner for acutely injured and/or critically ill patients. The stretcher permits performance of radiography and acts as a platform for critical care monitoring and patient support devices. During a 1-year period, the prototype CT-docking stretcher was used for 35 patients sustaining acute trauma and 25 patients from critical care units. Observations were elicited from physicians, nurses and technologists concerning the advantages or disadvantages of the docking stretcher. Advantages of the CT-docking stretcher included time saved in moving patients to the CT table from the admitting/emergency ward, transfer of critically ill patients onto the stretcher in the controlled environment of the intensive care unit rather than the CT suite, increasing CT throughput by direct docking of the patient stretcher to the CT scanner rather than manual transfer of complex support and monitoring devices with the patient, decreased risk associated with physical movement of patients with potentially unstable spinal injuries or unstable physiologic status, and decrease in potential for injury to medical personnel performing patient transfer

Radiation dose and cancer risk from pediatric CT examinations on 64-slice CT: A phantom study

International Nuclear Information System (INIS)

Feng Shiting; Law, Martin Wai-Ming; Huang Bingsheng; Ng, Sherry; Li Ziping; Meng Quanfei; Khong, Pek-Lan

2010-01-01

Objective: To measure the radiation dose from CT scans in an anthropomorphic phantom using a 64-slice MDCT, and to estimate the associated cancer risk. Materials and methods: Organ doses were measured with a 5-year-old phantom and thermoluminescent dosimeters. Four protocols; head CT, thorax CT, abdomen CT and pelvis CT were studied. Cancer risks, in the form of lifetime attributable risk (LAR) of cancer incidence, were estimated by linear extrapolation using the organ radiation doses and the LAR data. Results: The effective doses for head, thorax, abdomen and pelvis CT, were 0.7 mSv, 3.5 mSv, 3.0 mSv, 1.3 mSv respectively. The organs with the highest dose were; for head CT, salivary gland (22.33 mGy); for thorax CT, breast (7.89 mGy); for abdomen CT, colon (6.62 mGy); for pelvis CT, bladder (4.28 mGy). The corresponding LARs for boys and girls were 0.015-0.053% and 0.034-0.155% respectively. The organs with highest LARs were; for head CT, thyroid gland (0.003% for boys, 0.015% for girls); for thorax CT, lung for boys (0.014%) and breast for girls (0.069%); for abdomen CT, colon for boys (0.017%) and lung for girls (0.016%); for pelvis CT, bladder for both boys and girls (0.008%). Conclusion: The effective doses from these common pediatric CT examinations ranged from 0.7 mSv to 3.5 mSv and the associated lifetime cancer risks were found to be up to 0.16%, with some organs of higher radiosensitivity including breast, thyroid gland, colon and lungs.

CT arteriography of the upper abdomen

Energy Technology Data Exchange (ETDEWEB)

Hasuo, K; Matsuura, K; Baba, H; Numaguchi, Y; Komaki, S [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

1980-04-01

The technique of CT arteriography was introduced, and CT images of the upper abdomen were explained. Very clear enhancement of parenchyma and vessels (especially portal vein) of the object organs could be obtained by CT arteriography of the upper abdomen, anatomical structures of organs were identified more easily by CT arteriography than by conventional CT, and the amount of information obtained was increased by using CT arteriography. However, the indication of CT arteriography must be limited, because of its complexity that CT arteriography is performed after angiography and involves the invasion of patients' bodies. As described in many reports, CT arteriography is useful for malignant tumors of the liver, and it is worthwhile, especially when surgery for hepatocellular carcinoma is considered. CT arteriography for organs except the liver has not been discussed sufficiently. Therefore, an application of this method for other organs must be decided after consideration of the balance of the amount of information obtained by CT arteriography with invasion to patients.

Computed Tomography (CT) -- Head

Medline Plus

Full Text Available ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Blood Clots CT Perfusion of the Head CT Angiography ( ...

Functional CT imaging: load-dependent visualization of the subchondral mineralization by means of CT osteoabsorptionmetry (CT-OAM)

International Nuclear Information System (INIS)

Linsenmaier, U.; Schlichtenhorst, K.; Pfeifer, K.J.; Reiser, M.; Kersting, S.; Putz, R.; Mueller-Gerbl, M.

2003-01-01

Purpose: Functional computed tomography for visualization and quantification of subchondral bone mineralization using CT osteoabsorptiometry (CT-OAM). Materials and Methods: Tarsometatarsal (TMT) and metatarsophalangeal (MTP) joints of 46 human hallux valgus (HV) specimens were examined (sagittal 1/1/1 mm) on a single slice CT scanner SCT (Somatom Plus 4, Siemens AG). Subchondral bone pixels were segmented and assigned to 10 density value groups (triangle 100 HU, range 200 - 1200 HU) the pixels using volume rendering technique (VRT). The data analysis considered the severity of HV as determined by the radiographically measured HV-angle (a.p. projection). Results: CT-OAM could generate reproducible densitograms of the distribution pattern of the subchondral bone density for all four joint surfaces (TMT and MTP joints). The bone density localization enables the assignment to different groups, showing a characteristic HV-angle-dependent distribution of the maximum bone mineralization of the load-dependent densitogram (p [de

CT diagnosis of the primary lung cancer and usefulness of biopsy under CT

International Nuclear Information System (INIS)

Fujisawa, Hidefumi; Kushihashi, Tamio

2011-01-01

CT especially plays an important role in imaging diagnosis of lung cancer (LC) which gives quite multiple CT findings and this paper describes details to be noted for CT findings of individual lung lesion and cancer according to 5 classes below, together with usefulness of CT-guided biopsy and positron emission tomography (PET) usage. Explained are as follows: Important points in histopathology and CT findings from adenomatous hyperplasia (AH) to atypical AH (pre-invasive lesion); Differential CT diagnosis of benignity or malignancy of pulmonary nodes and tumors; Typical CT findings of LC of peripheral type of invasive or exclusive proliferative type, and pulmonary hillar type; Atypical CT findings of LC/having atypical inner structure such as presenting atypical calcification and atypical cavity/having atypical morphology such as presenting pneumonia-like finding, exhibiting regular or linear edge, and existing at atypical region like extrapleural lumen /having atypical progression rate such as showing rapid or slow doubling time of the volume and shrinking tentatively during the progress/of juvenile LC/and generated from background lung diseases such as interstitial pneumonia, tuberculosis, pneumoconiosis like asbestosis, pneumosilicosis, and pulmonary emphysema and bulla; and Regional ground glass opacity. As well, authors mention about the usefulness of CT-guided needle biopsy of the pulmonary lesion which enables to take the nodal specimen as small as <10 mm. Most frequent complication of the biopsy is pneumothorax (10-50%). How to use PET for LC examination is also commented with its usability and limitation. (T.T.)

CT of thymoma

Energy Technology Data Exchange (ETDEWEB)

Sone, S.; Higashihara, T.; Morimoto, S.; Ikezoe, J.; Arisawa, J. (Osaka Univ. (Japan). Faculty of Medicine)

1982-08-01

Based on 17 patients with thymoma (8 with myasthenia gravis and 9 free from it); 1. The effectiveness of CT, conventional radiography and pneumomediastinography in the detection of thymomas was determined and the results compared. 2. The CT findings of thymomas were discussed and the CT features which seemed to suggest malignant thymomas were evaluated. The results were as follows: 1. Of the 17 cass with thymomas, 13 were diagnosed from p-a films, 13 from lateral films, and 16 from CT. Of the 16 thymomas, 14 were diagnosed from lateral tomography. Mass densities were shown in all 15 cases in which pneumomediastinography were performed. 2. Benign thymomas showed round or oval smoothly marginated mass. The fatty plane between the mass and the mediastinal structures was nicely preserved. 3. Malignant thymoma frequently showed a plaque-like mass with more or less irregular or lobulated contours with obliteration of the fatty planes of the cardiovascular structures. Tumor calcification was shown in 4 of 10 malignant thymomas. 4. Slight tumor invasion to the mediastinal pleura and lung was difficult to predict from the CT images.

Does CT colonography have a role for population-based colorectal cancer screening?

NARCIS (Netherlands)

de Haan, Margriet C.; Halligan, Steve; Stoker, Jaap

2012-01-01

Colorectal cancer (CRC) is the second most common cancer and second most common cause of cancer-related deaths in Europe. CRC screening has been proven to reduce disease-specific mortality and several European countries employ national screening programmes. These almost exclusively rely on stool

Case Report: Rectal perforation during CT colonography [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Marianna Zukiwskyj

2016-03-01

Full Text Available Introduction Computer tomography colonoscopy (CTC is an increasingly prevalent procedure for the investigation of colorectal symptoms, or as a component of colorectal cancer screening.  It is considered a low risk procedure, however colonic perforation is a recognized significant complication.   Case Report We report the case of an 81-year-old female patient who underwent CTC after failed optical colonoscopy as part of routine colorectal cancer screening.  Perforation of the rectum with surrounding pararectal air was confirmed on CTC.  The patient had minimal symptoms and was treated successful non-operatively with bowel rest and antibiotics.   Conclusion Perforation sustained during CTC is an uncommon complication.  The incidence of perforation during CTC is still lower than that during optical colonoscopy.  In the absence of significant abdominal signs and symptoms, this rare complication may be successfully managed non-operatively.

Preoperative evaluation of renal anatomy and renal masses with helical CT, 3D-CT and 3D-CT angiography.

Science.gov (United States)

Toprak, Uğur; Erdoğan, Aysun; Gülbay, Mutlu; Karademir, Mehmet Alp; Paşaoğlu, Eşref; Akar, Okkeş Emrah

2005-03-01

The aim of this prospective study was to determine the efficacy of three-dimensional computed tomography (3D-CT) and three-dimensional computed tomographic angiography (3D-CTA) that were reconstructed by using the axial images of the multiphasic helical CT in the preoperative evaluation of renal masses and demonstration of renal anatomy. Twenty patients that were suspected of having renal masses upon initial physical examination and ultrasonographic evaluation were examined through multiphasic helical CT. Two authors executed CT evaluations. Axial images were first examined and then used to reconstruct 3D-CT and 3D- CTA images. Number, location and size of the renal masses and other findings were noted. Renal vascularization and relationships of the renal masses with the neighboring renal structures were further investigated with 3D-CT and 3D-CTA images. Out of 20 patients, 13 had histopathologically proven renal cell carcinoma. The diagnoses of the remaining seven patients were xanthogranulomatous pyelonephritis, abscess, simple cyst, infected cyst, angiomyolipoma, oncocytoma and arteriovenous fistula. In the renal cell carcinoma group, 3 patients had stage I, 7 patients had stage II, and 3 patients had stage III disease. Sizes of renal cell carcinoma masses were between 23 mm to 60 mm (mean, 36 mm). Vascular invasion was shown in 2 renal cell carcinoma patients. Collecting system invasion was identified in 11 of 13 renal cell patients. These radiologic findings were confirmed with surgical specimens. Three-dimensional CT and 3D-CTA are non-invasive, effective imaging techniques for the preoperative evaluation of renal masses.

ESGAR 2007. Book of abstracts

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-06-15

The book includes the abstracts of all contributions presented during ESGAR (European Society of Gastrointestinal and Abdominal Radiology) 2007. The contributions of the symposium and the scientific sessions cover the following topics: abdominal MRI; interactive liver diagnosis; rectal cancer; liver metastases; pancreas: technical advances, lesion characterisation and staging; hepatic interventions; upper GI tract: multimodality evaluation; Crohn's disease evaluation; focal liver lesions: multimodality evaluation; CTC-computer aided diagnosis; bile ducts: imaging and intervention; GI tract: imaging and intervention; small bowel and appendix: cross-sectional imaging; CT and MR colonography; trauma and acute abdominal conditions: imaging and intervention; vascular and diffuse liver disease; liver contrast enhanced US. The second part covers the abstract of 248 presentations.

Computed Tomography (CT) -- Sinuses

Medline Plus

Full Text Available ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement ...

Computed Tomography (CT) -- Head

Medline Plus

Full Text Available ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement ...

Abdominal and Pelvic CT

Medline Plus

Full Text Available ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement ...

Dynamic CT myocardial perfusion imaging

International Nuclear Information System (INIS)

Caruso, Damiano; Eid, Marwen; Schoepf, U. Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie

2016-01-01

Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

Brain tumor and CT, 1

International Nuclear Information System (INIS)

Suzuki, Nobuyuki; Katada, Kazuhiro; Shinomiya, Youichi; Sano, Hirotoshi; Kanno, Tetsuo

1981-01-01

It is very important for a neurosurgeon to know the consistency of a brain tumor preoperatively, since the information which is of much use in indicating the likely difficulty of the operation, which operative tools should be selected, the amount of bleeding to be expected from the tumor, and so on. The authors, therefore, tried to evaluate the consistency of brain tumors preoperatively 27 cases in which the margin of the tumor was made clear with a homogeneous stain were studied concerning the relationship between the tumor consistency and the CT findings. The results are as follows: 1) A higher CT number on a plain CT indicated a harder consistency of the tumor. 2) A lesser contrast index (CT number on enhancement CT/CT number on plain CT) showed a harder consistency of the tumor. (author)

Dynamic CT myocardial perfusion imaging

Energy Technology Data Exchange (ETDEWEB)

Caruso, Damiano [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncological and Pathological Sciences, University of Rome “Sapienza”, Latina (Italy); Eid, Marwen [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States); Jin, Kwang Nam [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul (Korea, Republic of); Varga-Szemes, Akos [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Tesche, Christian [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich (Germany); Mangold, Stefanie [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen (Germany); and others

2016-10-15

Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

Comparison of SPECT/CT, MRI and CT in diagnosis of skull base bone invasion in nasopharyngeal carcinoma.

Science.gov (United States)

Zhang, Shu-xu; Han, Peng-hui; Zhang, Guo-qian; Wang, Rui-hao; Ge, Yong-bin; Ren, Zhi-gang; Li, Jian-sheng; Fu, Wen-hai

2014-01-01

Early detection of skull base invasion in nasopharyngeal carcinoma (NPC) is crucial for correct staging, assessing treatment response and contouring the tumor target in radiotherapy planning, as well as improving the patient's prognosis. To compare the diagnostic efficacy of single photon emission computed tomography/computed tomography (SPECT/CT) imaging, magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of skull base invasion in NPC. Sixty untreated patients with histologically proven NPC underwent SPECT/CT imaging, contrast-enhanced MRI and CT. Of the 60 patients, 30 had skull base invasion confirmed by the final results of contrast-enhanced MRI, CT and six-month follow-up imaging (MRI and CT). The diagnostic efficacy of the three imaging modalities in detecting skull base invasion was evaluated. The rates of positive findings of skull base invasion for SPECT/CT, MRI and CT were 53.3%, 48.3% and 33.3%, respectively. The sensitivity, specificity and accuracy were 93.3%, 86.7% and 90.0% for SPECT/CT fusion imaging, 96.7%, 100.0% and 98.3% for contrast-enhanced MRI, and 66.7%, 100.0% and 83.3% for contrast-enhanced CT. MRI showed the best performance for the diagnosis of skull base invasion in nasopharyngeal carcinoma, followed closely by SPECT/CT. SPECT/CT had poorer specificity than that of both MRI and CT, while CT had the lowest sensitivity.

PET/CT and radiotherapy

International Nuclear Information System (INIS)

Messa, C.; CNR, Milano; S. Gerardo Hospital, Monza; Di Muzio, N.; Picchio, M.; Bettinardi, V.; Gilardi, M.C.; CNR, Milano; San Raffaele Scientific Institute, Milano; Fazio, F.; CNR, Milano; San Raffaele Scientific Institute, Milano; San Raffaele Scientific Institute, Milano

2006-01-01

This article reviews the state of the art of PET/CT applications in radiotherapy, specifically its use in disease staging, patient selection, treatment planning and treatment evaluation. Diseases for which radiotherapy with radical intent is indicated will be considered, as well as those in which PET/CT may actually change the course of disease. The methodological and technological aspects of PET/CT in radiotherapy are discussed, focusing on the problem of target volume definition with CT and PET functional imaging and the problem of tumor motion with respect to imaging and dose delivery

Slice sensitivity profiles and pixel noise of multi-slice CT in comparison with single-slice CT

International Nuclear Information System (INIS)

Schorn, C.; Obenauer, S.; Funke, M.; Hermann, K.P.; Kopka, L.; Grabbe, E.

1999-01-01

Purpose: Presentation and evaluation of slice sensitivity profile and pixel noise of multi-slice CT in comparison to single-slice CT. Methods: Slice sensitivity profiles and pixel noise of a multi-slice CT equiped with a 2D matrix detector array and of a single-slice CT were evaluated in phantom studies. Results: For the single-slice CT the width of the slice sensitivity profiles increased with increasing pitch. In spite of a much higher table speed the slice sensitivity profiles of multi-slice CT were narrower and did not increase with higher pitch. Noise in single-slice CT was independent of pitch. For multi-slice CT noise increased with higher pitch and for the higher pitch decreased slightly with higher detector row collimation. Conclusions: Multi-slice CT provides superior z-resolution and higher volume coverage speed. These qualities fulfill one of the prerequisites for improvement of 3D postprocessing. (orig.) [de

Adenocarcinoma Prostate With Neuroendocrine Differentiation: Potential Utility of 18F-FDG PET/CT and 68Ga-DOTANOC PET/CT Over 68Ga-PSMA PET/CT.

Science.gov (United States)

Parida, Girish Kumar; Tripathy, Sarthak; Datta Gupta, Shreya; Singhal, Abhinav; Kumar, Rakesh; Bal, Chandrasekhar; Shamim, Shamim Ahmed

2018-04-01

Ga-PSMA PET/CT is the upcoming imaging modality for staging, restaging and response assessment of prostate cancer. However, due to neuroendocrine differentiation in some of patients with prostate cancer, they express somatostatin receptors instead of prostate specific membrane antigen. This can be exploited and other modalities like Ga-DOTANOC PET/CT and F-FDG PET/CT should be used in such cases for guiding management. We hereby discuss a similar case of 67-year-old man of adenocarcinoma prostate with neuroendocrine differentiation, which shows the potential pitfall of Ga-PSMA PET/CT imaging and benefit of Ga-DOTANOC PET/CT and F-FDG PET/CT in such cases.

NMR-CT scanner

International Nuclear Information System (INIS)

Kose, Katsumi; Sato, Kozo; Sugimoto, Hiroshi; Sato, Masataka.

1983-01-01

A brief explanation is made on the imaging methods for a practical diagnostic NMR-CT scanner : A whole-body NMR-CT scanner utilizing a resistive magnet has been developed by Toshiba in cooperation with the Institute for Solid State Physics, the University of Tokyo. Typical NMR-CT images of volunteers and patients obtained in the clinical experiments using this device are presented. Detailed specifications are also shown about the practical NMR-CTs which are to be put on the market after obtaining the government approval. (author)

CT and HR-CT of exogenous allergic alveolitis

International Nuclear Information System (INIS)

Lederer, A.; Kullnig, P.; Pongratz, M.

1992-01-01

The CT changes on conventional and high resolution CT in 14 patients with exogeneous allergic alveolitis (EAA) were analysed retrospectively. There were 8 patients with clinically subacute disease, 5 patients in a chronic stage and 1 patient with acute EAA. The appearances and their distribution were examined. Seven of the 8 patients in the subacute stage showed a ground glass pattern and multiple nodules of less than 2 mm. All patients in the chronic stage showed a combination of fine infiltrates, small nodules and irregular linear densities; distortion of the pulmonary pattern was present in 3 cases. The patient with acute EAA showed diffuse dense areas of consolidation in both lungs as well as multiple nodules and a ground glass pattern. The CT appearances of EAA correspond with the basic micropathology and, within the clinical context, permit diagnostic classification. (orig.) [de

Coronary calcium screening with dual-source CT: reliability of ungated, high-pitch chest CT in comparison with dedicated calcium-scoring CT

Energy Technology Data Exchange (ETDEWEB)

Hutt, Antoine; Faivre, Jean-Baptiste; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain; Deken, Valerie [CHRU et Universite de Lille, Department of Biostatistics (EA 2694), Lille (France); Molinari, Francesco [Centre Hospitalier General de Tourcoing, Department of Radiology, Tourcoing (France)

2016-06-15

To investigate the reliability of ungated, high-pitch dual-source CT for coronary artery calcium (CAC) screening. One hundred and eighty-five smokers underwent a dual-source CT examination with acquisition of two sets of images during the same session: (a) ungated, high-pitch and high-temporal resolution acquisition over the entire thorax (i.e., chest CT); (b) prospectively ECG-triggered acquisition over the cardiac cavities (i.e., cardiac CT). Sensitivity and specificity of chest CT for detecting positive CAC scores were 96.4 % and 100 %, respectively. There was excellent inter-technique agreement for determining the quantitative CAC score (ICC = 0.986). The mean difference between the two techniques was 11.27, representing 1.81 % of the average of the two techniques. The inter-technique agreement for categorizing patients into the four ranks of severity was excellent (weighted kappa = 0.95; 95 % CI 0.93-0.98). The inter-technique differences for quantitative CAC scores did not correlate with BMI (r = 0.05, p = 0.575) or heart rate (r = -0.06, p = 0.95); 87.2 % of them were explained by differences at the level of the right coronary artery (RCA: 0.8718; LAD: 0.1008; LCx: 0.0139; LM: 0.0136). Ungated, high-pitch dual-source CT is a reliable imaging mode for CAC screening in the conditions of routine chest CT examinations. (orig.)

Clinical applications of SPECT-CT

Energy Technology Data Exchange (ETDEWEB)

Ahmadzadehfar, Hojjat; Biersack, Hans-Juergen (eds.) [University Hospital Bonn (Germany). Dept. of Nuclear Medicine

2014-06-01

Covers the full spectrum of clinical applications of SPECT/CT in diagnosis of benign and malignant diseases. Includes chapters on the use of SPECT/CT for dosimetry and for therapy planning. Completely up to date. Many helpful illustrations. SPECT/CT cameras have considerably improved diagnostic accuracy in recent years. Such cameras allow direct correlation of anatomic and functional information, resulting in better localization and definition of scintigraphic findings. In addition to this anatomic referencing, CT coregistration provides superior quantification of radiotracer uptake based on the attenuation correction capabilities of CT. Useful applications of SPECT/CT have been identified not only in oncology but also in other specialties such as orthopedics and cardiology. This book covers the full spectrum of clinical applications of SPECT/CT in diagnosis and therapy planning of benign and malignant diseases. Opening chapters discuss the technology and physics of SPECT/CT and its use for dosimetry. The role of SPECT/CT in the imaging of a range of pathologic conditions is then addressed in detail. Applications covered include, among others, imaging of the thyroid, bone, and lungs, imaging of neuroendocrine tumors, cardiac scintigraphy, and sentinel node scintigraphy. Individual chapters are also devoted to therapy planning in selective internal radiation therapy of liver tumors and bremsstrahlung SPECT/CT. Readers will find this book to be an essential and up-to-date source of information on this invaluable hybrid imaging technique.

Comparison of the 68Ga-DOTATATA PET/CT, FDG PET/CT, and MIBG SPECT/CT in the Evaluation of Suspected Primary Pheochromocytomas and Paragangliomas.

Science.gov (United States)

Jing, Hongli; Li, Fang; Wang, Ling; Wang, Zhenghua; Li, Wei; Huo, Li; Zhang, Jingjing

2017-07-01

Anatomical imaging modalities including CT and MRI are the mainstay of evaluation of primary pheochromocytoma or paraganglioma. However, nuclear medicine imaging is frequently necessary to determine the nature of the lesions. The purpose of this investigation is to assess which commonly used nuclear medicine modality might have a better diagnostic value in this clinical setting. Eight patients who had been suspected of having either primary pheochromocytoma or primary paraganglioma and 1 patient with known pheochromocytoma were included in the analysis. Among the 8 patients without known diagnosis, 7 had been suggested by anatomical imaging modalities, whereas one of them presented with initial negative anatomical imaging interpretation. All of 9 patients underwent Ga-DOTATATA PET/CT, FDG PET/CT, and MIBG SPECT/CT for further evaluation. The imaging findings were compared with postsurgical pathology and follow-up. Both Ga-DOTATATA PET/CT and MIBG SPECT/CT accurately identified 9 primary tumors, whereas FDG PET/CT showed increased activity in 8 of 9 primary tumors. Both Ga-DOTATATA and FDG PET/CT are able to detect associated extra-adrenal lesions not shown on MIBG study in patients with multiple endocrine neoplasia syndrome. Ga-DOTATATA PET/CT could be the nuclear medicine imaging choice to evaluate suspected primary pheochromocytoma or paraganglioma, especially in the situation of multiple endocrine neoplasia syndrome.

CT findings of infant epilepsy

International Nuclear Information System (INIS)

Hojoh, Hiroatsu; Kataoka, Kenkichi; Nakagawa, Yoshihiro; Nakano, Shozo; Tomita, Yutaka.

1982-01-01

CT diagnosis of infantile epilepsy was evaluated. High incidence of abnormal CT findings in infantile spasms and Lennox-Gastaut syndrome was same as in other reports. Comparison between CT findings and neurological complications and that between CT findings and electroencephalogram findings revealed a stronger relationship existing in the former. This suggested that CT is more useful as a measure to detect underlying diseases which are due to organic change of the brain to cause epilepsy, rather than as that to disclose epileptic primary lesions of functional change. (Ueda, J.)

CT of thymoma

International Nuclear Information System (INIS)

Sone, Shusuke; Higashihara, Tokuro; Morimoto, Shizuo; Ikezoe, Junpei; Arisawa, Jun

1982-01-01

Based on 17 patients with thymoma (8 with myasthenia gravis and 9 free from it); 1. The effectiveness of CT, conventional radiography and pneumomediastinography in the detection of thymomas was determined and the results compared. 2. The CT findings of thymomas were discussed and the CT features which seemed to suggest malignant thymomas were evaluated. The results were as follows: 1. Of the 17 cases with thymomas, 13 were diagnosed from p-a films, 13 from lateral films, and 16 from CT. Of the 16 thymomas, 14 were diagnosed from lateral tomography. Mass densities were shown in all 15 cases in which pneumomediastinography were performed. 2. Benign thymomas showed round or oval smoothly marginated mass. The fatty plane between the mass and the mediastinal structures was nicely preserved. 3. Malignant thymoma frequently showed a plaque-like mass with more or less irregular or lobulated contoures with obliteration of the fatty planes of the cardiovascular structures. Tumor calcification was shown in 4 of 10 malignant thymomas. 4. Slight tumor invasion to the mediastinal pleura and lung was difficult to predict from the CT images. (author)

F-FDG PET/CT (PET/CT) influences management in patients with known or suspected pancreatic cancer

International Nuclear Information System (INIS)

Barber, Thomas W.; Kalff, Victor; Cherk, Martin H.; Yap, Kenneth SK.; Evans, Peter; Kelly, Michael J.

2009-01-01

Full text: Objective: To assess the impact on clinical management of PET/CT in patients with known or suspected pancreatic cancer. Methods: Between April 2006 and September 2008,25 PET/CT scans were performed using a dedicated PET/CT (22 scans) or a coincidence hybrid PET/CT camera (3 scans) in 23 patients with known or suspected pancreatic cancer. 17 scans were performed for initial evaluation and 8 for restaging of disease. The pre-PET/CT management plan and for intent were prospectively recorded in all cases. The post-PET/CT management plan was determined from the medical record and for discussions with treating clinicians. The impact of PET/CT on management was classified as High, Medium, Low or None, defined using ANZAPNM PET data collection project criteria. Follow-up was used to reconcile any discordance between PET/CT and conventional imaging. Results: Overall, PET/CT management impact was classified as high (n equal 7), medium (n equal 4), low (n equal 10) or none (n equal 4). Impact was either high or medium in l l/25 patients (44%) (95% confidence interval; 24 - 64%). Impact was high in 4/17 patients imaged for initial evaluation, predominantly by clarifying equivocal lesions on conventional imaging. In restaged patients, PET/CT impact was high in 3/8, and it correctly modified disease extent in 5/8. In the 16 discordant studies, PET/CT assessment was correct in 10, conventional imaging in 4 and there was insufficient information in 2. Conclusion: PET/CT has high or medium management impact in 44% of patients imaged for known or suspected pancreatic cancer, more commonly during restaging. Discordant PET/CT results were usually correct.

SedCT: MATLAB™ tools for standardized and quantitative processing of sediment core computed tomography (CT) data collected using a medical CT scanner

Science.gov (United States)

Reilly, B. T.; Stoner, J. S.; Wiest, J.

2017-08-01

Computed tomography (CT) of sediment cores allows for high-resolution images, three-dimensional volumes, and down core profiles. These quantitative data are generated through the attenuation of X-rays, which are sensitive to sediment density and atomic number, and are stored in pixels as relative gray scale values or Hounsfield units (HU). We present a suite of MATLAB™ tools specifically designed for routine sediment core analysis as a means to standardize and better quantify the products of CT data collected on medical CT scanners. SedCT uses a graphical interface to process Digital Imaging and Communications in Medicine (DICOM) files, stitch overlapping scanned intervals, and create down core HU profiles in a manner robust to normal coring imperfections. Utilizing a random sampling technique, SedCT reduces data size and allows for quick processing on typical laptop computers. SedCTimage uses a graphical interface to create quality tiff files of CT slices that are scaled to a user-defined HU range, preserving the quantitative nature of CT images and easily allowing for comparison between sediment cores with different HU means and variance. These tools are presented along with examples from lacustrine and marine sediment cores to highlight the robustness and quantitative nature of this method.

CT in normal pressure hydrocephalus. Correlation between CT and clinical response to shunting

Energy Technology Data Exchange (ETDEWEB)

Fujita, K.; Nogaki, H.; Noda, M.; Kusunoki, T.; Tamaki, N. (Kobe Univ. (Japan). School of Medicine)

1981-02-01

CT scans were obtained on 33 patients (age 73y. to 31y.) with the diagnosis of normal pressure hydrocephalus. In each case, the diagnosis was made on the basis of the symptoms, CT and cisternographic findings. Underlying diseases of normal pressure hydrocephalus are ruptured aneurysms (21 cases), arteriovenous malformations (2 cases), head trauma (1 case), cerebrovascular accidents (1 case) and idiopathie (8 cases). Sixteen of 33 patients showed marked improvement, five, moderate or minimal improvement, and twelve, no change. The results were compared with CT findings and clinical response to shunting. CT findings were classified into five types, bases on the degree of periventricular hypodensity (P.V.H.), the extent of brain damage by underlying diseases, and the degree of cortical atrophy. In 17 cases of type (I), CT shows the presence of P.V.H. with or without minimal frontal lobe damage and no cortical atrophy. The good surgical improvements were achieved in all cases of type (I) by shunting. In 4 cases of type (II), CT shows the presence of P.V.H. and severe brain damage without cortical atrophy. The fair clinical improvements were achieved in 2 cases (50%) by shunting. In one case of type (III), CT shows the absence of P.V.H. without brain damage nor cortical atrophy. No clinical improvement was obtained by shunting in this type. In 9 cases of type (IV) with mild cortical atrophy, the fair clinical improvement was achieved in two cases (22%) and no improvement in 7 cases. In 2 cases of type (V) with moderate or marked cortical atrophy, no clinical improvement was obtained by shunting. In conclusion, it appeared from the present study that there was a good correlation between the result of shunting and the type of CT, and clinical response to shunting operation might be predicted by classification of CT findings.

Estimation of skull table thickness with clinical CT and validation with microCT.

Science.gov (United States)

Lillie, Elizabeth M; Urban, Jillian E; Weaver, Ashley A; Powers, Alexander K; Stitzel, Joel D

2015-01-01

Brain injuries resulting from motor vehicle crashes (MVC) are extremely common yet the details of the mechanism of injury remain to be well characterized. Skull deformation is believed to be a contributing factor to some types of traumatic brain injury (TBI). Understanding biomechanical contributors to skull deformation would provide further insight into the mechanism of head injury resulting from blunt trauma. In particular, skull thickness is thought be a very important factor governing deformation of the skull and its propensity for fracture. Current computed tomography (CT) technology is limited in its ability to accurately measure cortical thickness using standard techniques. A method to evaluate cortical thickness using cortical density measured from CT data has been developed previously. This effort validates this technique for measurement of skull table thickness in clinical head CT scans using two postmortem human specimens. Bone samples were harvested from the skulls of two cadavers and scanned with microCT to evaluate the accuracy of the estimated cortical thickness measured from clinical CT. Clinical scans were collected at 0.488 and 0.625 mm in plane resolution with 0.625 mm thickness. The overall cortical thickness error was determined to be 0.078 ± 0.58 mm for cortical samples thinner than 4 mm. It was determined that 91.3% of these differences fell within the scanner resolution. Color maps of clinical CT thickness estimations are comparable to color maps of microCT thickness measurements, indicating good quantitative agreement. These data confirm that the cortical density algorithm successfully estimates skull table thickness from clinical CT scans. The application of this technique to clinical CT scans enables evaluation of cortical thickness in population-based studies. © 2014 Anatomical Society.

CT-based virtual tracheobronchoscopy in children - comparison with axial CT and multiplanar reconstruction: preliminary results

International Nuclear Information System (INIS)

Sorantin, Erich; Lindbichler, Franz; Eber, Ernst; Schimpl, Guenther

2002-01-01

Background: 3D post-processing of spiral-CT (S-CT) data using perspective projection allows the generation of virtual views similar to endoscopy. Objective: To evaluate whether simultaneous reading of axial S-CT, multiplanar reconstruction (MPR) and virtual tracheobronchoscopy (VTB) is more precise and accurate than reading of axial S-CT and MPR alone in paediatric patients. Materials and methods: S-CT studies of 15 symptomatic and 4 normal patients were investigated. Two radiologists independently read two sets of images for airway abnormalities: first axial CT and MPR, followed by axial CT, MPR and VTB. A final decision was later made by consensus. All results were compared to fibre-optic bronchoscopy (FTB). Interobserver agreement was used as an indicator of precision for the display technique used. Results: At reading of axial S-CT and MPR an interobserver agreement of 89.5% (κ=0.776, P<0.00103) was found. Based on the consensus decision, a diagnostic accuracy of 89.5% at a sensitivity 86.6% and specificity of 100% (κ=0.776, 95% CI 0.491-1.062, P<0.00103) was achieved. At reporting on axial S-CT, MPR and VTB, all cases were classified correctly by both readers, indicating 100% accuracy, interobserver agreement, sensitivity and specificity (κ=1.00, 95% CI 1.0-1.0, P<0.000258). Conclusions: The simultaneous display of axial S-CT, MPR and VTB raises the precision, accuracy and sensitivity of radiological reports. (orig.)

CT of splenic trauma

International Nuclear Information System (INIS)

Griffiths, B.G.; Federle, M.P.; Minagi, H.; Jeffrey, R.B.

1986-01-01

Fifty-five consecutive cases of surgically proved splenic injuries were evaluated by CT. CT correctly identified 54 splenic injuries, with one false-negative and three false-positive studies. In the single false-negative study and in two of the three false-positive studies, CT correctly indicated the presence of a large hemoperitoneum and other abdominal visceral lacerations and so correctly indicated the need for surgery. Of the 55 proved cases of splenic injury, CT revealed hemoperitoneum in 54 (99%), perisplenic clot in 47 (85%), splenic laceration in 39 (71%), and subcapsular hematoma in 13 (24%). Perisplenic clot can be distinguished from lysed blood in the peritoneal cavity and is a sensitive and specific sign of splenic trauma, even in the absence of visible splenic laceration. The authors conclude that CT is highly reliable means of evaluating splenic trauma

Evaluation of pre and post-operative spinal plain CT and CT-myelography

International Nuclear Information System (INIS)

Nagase, Joji; Inoue, Shunichi; Miyasaka, Hitoshi; Kamata, Sakae; Shinohara, Hiroyasu.

1983-01-01

Confirmation of the level of scan slices is essential for the CT diagnosis of spinal and spinal-cord diseases. Pre- and postoperative comparison should be made on the same level. For reading of plain CT and CTM, window levels should be identical pre- and postoperatively. Both methods demonstrated the spinal canal, morphology of the spinal cord, and three-Fdimensional pathologic pictures inside and outside the spinal cord. Preoperative CT contributed useful information on the pathologic conditions and selection of surgical procedures and routes. Postoperative plain CT confirmed surgical results, and CTM revealed the spinal cord and the subarachnoid space, as well as the range and degree of decompression from the spinal cord. (Chiba, N.)

Children's (Pediatric) CT (Computed Tomography)

Medline Plus

Full Text Available ... view of the body's interior. Refinements in detector technology allow new CT scanners to obtain multiple slices in a single rotation. These scanners, called "multislice CT" or "multidetector CT," ...

SPECT/CT and pulmonary embolism

Energy Technology Data Exchange (ETDEWEB)

Mortensen, Jann [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); The Faroese National Hospital, Department of Medicine, Torshavn (Faroe Islands); Gutte, Henrik [Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Herlev Hospital, Copenhagen University Hospital, Department of Radiology, Copenhagen (Denmark); University of Copenhagen, Cluster for Molecular Imaging, Faculty of Health Sciences, Copenhagen (Denmark)

2014-05-15

Acute pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/P) scintigraphy or pulmonary CT angiography (CTPA). In recent years both techniques have improved. Many nuclear medicine centres have adopted the single photon emission CT (SPECT) technique as opposed to the planar technique for diagnosing PE. SPECT has been shown to have fewer indeterminate results and a higher diagnostic value. The latest improvement is the combination of a low-dose CT scan with a V/P SPECT scan in a hybrid tomograph. In a study comparing CTPA, planar scintigraphy and SPECT alone, SPECT/CT had the best diagnostic accuracy for PE. In addition, recent developments in the CTPA technique have made it possible to image the pulmonary arteries of the lungs in one breath-hold. This development is based on the change from a single-detector to multidetector CT technology with an increase in volume coverage per rotation and faster rotation. Furthermore, the dual energy CT technique is a promising modality that can provide functional imaging in combination with anatomical information. Newer high-end CT scanners and SPECT systems are able to visualize smaller subsegmental emboli. However, consensus is lacking regarding the clinical impact and treatment. In the present review, SPECT and SPECT in combination with low-dose CT, CTPA and dual energy CT are discussed in the context of diagnosing PE. (orig.)

Variation in quantitative CT air trapping in heavy smokers on repeat CT examinations

Energy Technology Data Exchange (ETDEWEB)

Mets, Onno M.; Gietema, Hester A.; Jong, Pim A. de [University Medical Center Utrecht, Radiology, Heidelberglaan 100, Postbus 85500, Utrecht (Netherlands); Isgum, Ivana; Mol, Christian P. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands); Zanen, Pieter [University Medical Center Utrecht, Pulmonology, Utrecht (Netherlands); Prokop, Mathias [Radboud University Nijmegen Medical Centre, Radiology, Nijmegen (Netherlands); University Medical Center Utrecht, Radiology, Heidelberglaan 100, Postbus 85500, Utrecht (Netherlands)

2012-12-15

To determine the variation in quantitative computed tomography (CT) measures of air trapping in low-dose chest CTs of heavy smokers. We analysed 45 subjects from a lung cancer screening trial, examined by CT twice within 3 months. Inspiratory and expiratory low-dose CT was obtained using breath hold instructions. CT air trapping was defined as the percentage of voxels in expiratory CT with an attenuation below -856 HU (EXP{sub -856}) and the expiratory to inspiratory ratio of mean lung density (E/I-ratio{sub MLD}). Variation was determined using limits of agreement, defined as 1.96 times the standard deviation of the mean difference. The effect of both lung volume correction and breath hold reproducibility was determined. The limits of agreement for uncorrected CT air trapping measurements were -15.0 to 11.7 % (EXP{sub -856}) and -9.8 to 8.0 % (E/I-ratio{sub MLD}). Good breath hold reproducibility significantly narrowed the limits for EXP{sub -856} (-10.7 to 7.5 %, P = 0.002), but not for E/I-ratio{sub MLD} (-9.2 to 7.9 %, P = 0.75). Statistical lung volume correction did not improve the limits for EXP{sub -856} (-12.5 to 8.8 %, P = 0.12) and E/I-ratio{sub MLD} (-7.5 to 5.8 %, P = 0.17). Quantitative air trapping measures on low-dose CT of heavy smokers show considerable variation on repeat CT examinations, regardless of lung volume correction or reproducible breath holds. (orig.)

Clinical values of CT and dynamic CT in brain infarction

International Nuclear Information System (INIS)

Lim, Soo Il; Jang, Do; Seo, Eun Joo; Sohn, Myung Hee; Choi, Ki Chul

1985-01-01

With the advent of faster scan time and new computer program, a scanning technique called 'dynamic computed tomography' has become possible. Dynamic computed tomography consisted of performing multiple rapid sequence scans after injection of contrast material. The authors have evaluated the clinical usefulness of computed tomography and dynamic computed tomography of 93 patients with brain infarction and/or ischemia during the period of 17 months from April 1983 to August 1984 in Department of Radiology, Chonbuk National University Hospital. The results were as follows; 1. The age distribution ranged from 18 years to 78 years. Among them the most common age group was between 50 years and 59 years (40.9%). 2. The sites of brain infarction were cerebral lobes (63 cases,68), basal ganglia (15 cases, 16.1%) and multiple sites (6 cases, 6.4%). The common affected site was middle cerebral artery territories. 3. The contrast enhancement of acute infarction was noted in 14 cases (17.5%) which occurred commonly between 3 days and 2 weeks from ictus. 4. The patterns of time-density curve in brain infarction and/or ischemia were as follow: a. Depression of slow wash-in phase was 20 cases (59%). b. Lower peak concentration was 17 cases (50%). c. Lower and delayed peak concentration was 7 cases (21%). d. No definite peak concentration was 6 cases (18%). First three patterns of time-density curve were thought as relatively characteristic curve of brain infarction and/or ischemia. 5. Two cases that showed negative findings on precontrast CT scan appeared to be positive findings as hypodensity on postcontrast CT scan and were confirmed as brain infarction by dynamic CT. 6. The diagnostic entity of dynamic CT scan were as follows; a. large artery thrombotic infarction were 23 cases (58%). b. lacnar infarction were 6 cases (15%). c. ischemia were 5 cases (13%). d. normal were 5 cases (13%). In six cases of lacunar infarction which was double hypodensity on pre-and postcontrast CT

Clinical values of CT and dynamic CT in brain infarction

Energy Technology Data Exchange (ETDEWEB)

Lim, Soo Il; Jang, Do; Seo, Eun Joo; Sohn, Myung Hee; Choi, Ki Chul [Chonbuk National University College of Medicine, Jeonju (Korea, Republic of)

1985-04-15

With the advent of faster scan time and new computer program, a scanning technique called 'dynamic computed tomography' has become possible. Dynamic computed tomography consisted of performing multiple rapid sequence scans after injection of contrast material. The authors have evaluated the clinical usefulness of computed tomography and dynamic computed tomography of 93 patients with brain infarction and/or ischemia during the period of 17 months from April 1983 to August 1984 in Department of Radiology, Chonbuk National University Hospital. The results were as follows; 1. The age distribution ranged from 18 years to 78 years. Among them the most common age group was between 50 years and 59 years (40.9%). 2. The sites of brain infarction were cerebral lobes (63 cases,68), basal ganglia (15 cases, 16.1%) and multiple sites (6 cases, 6.4%). The common affected site was middle cerebral artery territories. 3. The contrast enhancement of acute infarction was noted in 14 cases (17.5%) which occurred commonly between 3 days and 2 weeks from ictus. 4. The patterns of time-density curve in brain infarction and/or ischemia were as follow: a. Depression of slow wash-in phase was 20 cases (59%). b. Lower peak concentration was 17 cases (50%). c. Lower and delayed peak concentration was 7 cases (21%). d. No definite peak concentration was 6 cases (18%). First three patterns of time-density curve were thought as relatively characteristic curve of brain infarction and/or ischemia. 5. Two cases that showed negative findings on precontrast CT scan appeared to be positive findings as hypodensity on postcontrast CT scan and were confirmed as brain infarction by dynamic CT. 6. The diagnostic entity of dynamic CT scan were as follows; a. large artery thrombotic infarction were 23 cases (58%). b. lacnar infarction were 6 cases (15%). c. ischemia were 5 cases (13%). d. normal were 5 cases (13%). In six cases of lacunar infarction which was double hypodensity on pre

CT findings at lupus mesenteric vasculitis

International Nuclear Information System (INIS)

Ko, S.F.; Lee, T.Y.; Cheng, T.T.; Ng, S.H.; Lai, H.M.; Cheng, Y.F.; Tsai, C.C.

1997-01-01

Purpose: To describe the spectrum of early CT findings of lupus mesenteric vasculitis (LMV) and to assess the utility of CT in the management of this uncommon entity. Methods: Abdominal CT was performed within 1-4 days (average 2.2 days) of the onset of severe abdominal pain and tenderness in 15 women with systemic lupus erythematosus. Prompt high-dose i.v. corticosteroid in 11 patients after the CT diagnosis of LMV was made. CT was performed after abdominal symptoms subsided. Results: Eleven cases revealed CT features suggestive of LMV including conspicuous prominence of mesentric vessels with palisade pattern or comb-like appearance (CT comb sign) supplying focal or diffuse dilated bowel loops (n=11), ascites with slightly increased peritoneal enhancement (n=11), small bowel wall thickening (n=10) with double halo or target sign (n=8). Follow-up CT before high-dose steroid therapy revealed complete or marked resolution of the abnormal CT findings. Conclusion: CT is helpful for confirming the diagnosis of LMV, especially the comb sign which may be an early sign. Bowel ischemia due to LMV is less ominous than previously expected, and the abnormal CT findings were reversible when early diagnosis and prompt i.v. steroid therapy could be achieved. (orig.)

CT findings at lupus mesenteric vasculitis

Energy Technology Data Exchange (ETDEWEB)

Ko, S.F. [Chang Gung Medical College and Memorial Hospital, Dept. of Radiology, Kaohsiung Hsien (Taiwan); Lee, T.Y. [Chang Gung Medical College and Memorial Hospital, Dept. of Radiology, Kaohsiung Hsien (Taiwan); Cheng, T.T. [Chang Gung Medical College and Memorial Hospital, Dept. of Rheumatology, Kaohsiung Hsien (Taiwan); Ng, S.H. [Chang Gung Medical College and Memorial Hospital, Dept. of Radiology, Kaohsiung Hsien (Taiwan); Lai, H.M. [Chang Gung Medical College and Memorial Hospital, Dept. of Rheumatology, Kaohsiung Hsien (Taiwan); Cheng, Y.F. [Chang Gung Medical College and Memorial Hospital, Dept. of Radiology, Kaohsiung Hsien (Taiwan); Tsai, C.C. [Chang Gung Medical College and Memorial Hospital, Dept. of Radiology, Kaohsiung Hsien (Taiwan)

1997-01-01

Purpose: To describe the spectrum of early CT findings of lupus mesenteric vasculitis (LMV) and to assess the utility of CT in the management of this uncommon entity. Methods: Abdominal CT was performed within 1-4 days (average 2.2 days) of the onset of severe abdominal pain and tenderness in 15 women with systemic lupus erythematosus. Prompt high-dose i.v. corticosteroid in 11 patients after the CT diagnosis of LMV was made. CT was performed after abdominal symptoms subsided. Results: Eleven cases revealed CT features suggestive of LMV including conspicuous prominence of mesentric vessels with palisade pattern or comb-like appearance (CT comb sign) supplying focal or diffuse dilated bowel loops (n=11), ascites with slightly increased peritoneal enhancement (n=11), small bowel wall thickening (n=10) with double halo or target sign (n=8). Follow-up CT before high-dose steroid therapy revealed complete or marked resolution of the abnormal CT findings. Conclusion: CT is helpful for confirming the diagnosis of LMV, especially the comb sign which may be an early sign. Bowel ischemia due to LMV is less ominous than previously expected, and the abnormal CT findings were reversible when early diagnosis and prompt i.v. steroid therapy could be achieved. (orig.).

The impact of the PET/CT in comparison with the same day contrast enhanced CT in breast cancer management

International Nuclear Information System (INIS)

Piperkova, E.; Raphael, B.; Altinyay, M.; Castellon, I.; Libes, R.; Abdel-Dayem, H.

2006-01-01

Full text: The aim of this study is to evaluate the impact of 18F-fluorodeoxyglucose FDG positron emission tomography with fused computerized tomography (PET/CT) in comparison with the same day contrast enhanced CT (CE-CT) in the breast cancer (BC) management. 68 studies in 48 BC patients, 8 for initial and 60 for restaging disease, after surgery, radiation/chemotherapy, for radiation therapy planning or evaluating treatment response were included. All patients underwent whole body PET/CT for diagnostic purposes followed by CE-CT diagnostic scans of selected body regions. PET/CT was performed approximately 90 minutes following 10-15 mCi of 18F-FDG on a GE Discovery PET/CT system. CT part acquired with low dose X-ray for localization and attenuation correction. The CE-CT was performed according to departmental protocol. Out of a total of 235 lesions in 68 PET/CT and CE-CT studies, 189 were concordant between PET/CT and CE-CT. However, there were 46 discordant lesions, which were verified by either follow-up or biopsy. PET/CT correctly identified 25 (True Positive-TP). CE-CT identified 2 TP lesions missed by PET/CT (False negative): one liver metastasis with necrosis, which is a known non-avid FDG, the other was a missed abdominal metastatic node, which did not change staging or treatment. PET/CT incorrectly identified 2 lesions (False Positive) while CE-CT incorrectly identified 17 FP. For evaluating treatment response in 40 follow up studies PET/CT reported complete response in 15, partial response in 11, stable disease in 2, progression in 5, and free of disease following surgery - in 7. The CE-CT described progression of the disease in 1 PET/CT true negative study and no progression in 2 TP PET/CT studies. In this study, PET/CT played more important role than CECT scans alone and provided an impact on the management of BC patients

CT, MRI, and FDG PET/CT findings of sinonasal sarcoma: Differentiation from squamous cell carcinoma

International Nuclear Information System (INIS)

Kim, Jin Ho; Yoon, Dae Young; Baek, Sora; Park, Min Woo; Kwon, Kee Hwan; Rho, Young Soo

2016-01-01

To evaluate computed tomography (CT), magnetic resonance imaging (MRI), and 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) findings for the differentiation of sinonasal sarcoma from squamous cell carcinoma (SCC). We retrospectively reviewed CT, MRI, and FDG PET/CT results in 20 patients with pathologically proven sinonasal sarcoma (n = 7) and SCC (n = 13). Imaging characteristics of tumors, such as the shape, size, margin, MRI signal intensity, pattern of enhancement, local tumor invasion, and maximum standardized uptake value (SUVmax) were analyzed and compared between sarcoma and SCC. The SUVmax of sarcomas (7.4 ± 2.1) was significantly lower than the SUVmax of the SCCs (14.3 ± 4.5) (p = 0.0013). However, no significant difference in the shape, size, margin, MRI signal intensity, pattern of enhancement, and local tumor invasion was observed between sarcoma and SCC. Although CT and MR imaging features are nonspecific, FDG PET/CT is useful in distinguishing between sinonasal sarcoma and SCC based on the SUVmax value

CT, MRI, and FDG PET/CT findings of sinonasal sarcoma: Differentiation from squamous cell carcinoma

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Kim, Jin Ho; Yoon, Dae Young; Baek, Sora; Park, Min Woo; Kwon, Kee Hwan; Rho, Young Soo [Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of)

2016-07-15

To evaluate computed tomography (CT), magnetic resonance imaging (MRI), and 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) findings for the differentiation of sinonasal sarcoma from squamous cell carcinoma (SCC). We retrospectively reviewed CT, MRI, and FDG PET/CT results in 20 patients with pathologically proven sinonasal sarcoma (n = 7) and SCC (n = 13). Imaging characteristics of tumors, such as the shape, size, margin, MRI signal intensity, pattern of enhancement, local tumor invasion, and maximum standardized uptake value (SUVmax) were analyzed and compared between sarcoma and SCC. The SUVmax of sarcomas (7.4 ± 2.1) was significantly lower than the SUVmax of the SCCs (14.3 ± 4.5) (p = 0.0013). However, no significant difference in the shape, size, margin, MRI signal intensity, pattern of enhancement, and local tumor invasion was observed between sarcoma and SCC. Although CT and MR imaging features are nonspecific, FDG PET/CT is useful in distinguishing between sinonasal sarcoma and SCC based on the SUVmax value.

CT of hepatocellular carcinoma

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Nakamura, H; Tanaka, T; Sai, H; Kawamoto, S; Morimoto, K [Osaka Univ. (Japan). Faculty of Medicine

1982-06-01

CT was investigated in 125 cases of hepatocelluar carcinoma and 47 cases of metastatic hepatic neoplasm. The entire contour of each tumor was traced and the average CT value in the tumor was estimated. As a result, the CT value for hepatocellular carcinoma tended to be higher on plain CT and also after contrast enhancement. The CT findings seen frequently were as follows: capsule in 76 cases (60.8%) and septum in 67 cases (53.6%); tumor thrombus in portal vein in 39 cases (31.2%) and that in inferior vena cava in 3 cases (2.4%); localized enlargement of hepatic bile duct in 24 cases (19.2%). These findings were rarely seen in the cases of metastatic hepatic neoplasm. As a relatively outstanding feature of hepatic metastases, a double contour, like concentric circles or contour lines, with a relatively large inner circle or contour line, was found in 21 cases (44.7%). By paying attention to the change of CT value on contrast enhancement and the characteristic image of each case, hepatocellular carcinoma could be differentiated from metastatic hepatic neoplasm with high probability.

Head trauma and CT

International Nuclear Information System (INIS)

Samejima, Kanji; Yoshii, Nobuo; Tobari, Chitoshi

1979-01-01

It has been said that chronic subdural hematoma cannot be diagnosed by CT. In our cases, CT was used, and the results were described. According to the density of the picture, CT findings of chronic subdural hematoma could be classified into 3 types, those of higher density than that of the cerebral paranchyma, those of isodensity, and those of lower density than that of the cerebral parenchyma. The difference among them appeared to be due to variation in the fluid in hematoma, especially that in hemoglobin concentration. Chronic subdural hematoma was found in 27 of 388 cases of head trauma in which CT was undertaken in our department of surgery for last 2 years. It is difficult to differenciate this disease from subdural edema or subarachnoideal retention of the cerebrospinal fluid. In many cases, use of contrast medium added no change to the CT picture. Cerebral angiography is necessary for definite diagnosis of the disease. Chronic subdural hematoma gives more varieties of findings than other intracranial hematomas. However, if the film is very carefully read, CT is still useful for diagnosing this disease in spite of initially remarked difficulties. (Ueda, J.)

Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model.

Science.gov (United States)

Rosow, David E; Sahani, Dushyant; Strobel, Oliver; Kalva, Sanjeeva; Mino-Kenudson, Mari; Holalkere, Nagaraj S; Alsfasser, Guido; Saini, Sanjay; Lee, Susanna I; Mueller, Peter R; Fernández-del Castillo, Carlos; Warshaw, Andrew L; Thayer, Sarah P

2005-12-01

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findings--compared with pathologic diagnoses-- predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia.

CT-guided stereotactic neurosurgery

International Nuclear Information System (INIS)

Takizawa, Takaaki; Sato, Shoju; Matsumoto, Akira; Sano, Akira; Takahashi, Kazunori; Murakami, Yuji; Ohta, Kosuke

1985-01-01

Brown-Roberts-Wells stereotactic instruments were used for CT guided stereotactic surgery in 54 cases (65 operations). Stereotactic biopsy was done in 9 cases and successive regional chemotherapy was done in 3 cases. Stereotactic drainage was done in 2 cases of bacterial abcess, 3 cases of cystic neoplasm and 33 cases (43 operations) of intracerebral hematoma. CT guided stereotactic procedure was valuable for the correct cannulation to the center of the cavity. We tried to utilize CT image for the selection of targets for stereotactic functional neurosurgical procedures in 6 cases. In the cases of thalamotomy, the information derived from CT made the operation safer than that by contrast ventriculography alone. In all cases of electrode implantation for deep brain stimulation, accurate and precise electrode placement was achieved from CT images alone. This rapid and easy surgical technique was useful also for poor risk patients. (author)

Thyroid lymphography-computed tomography (TLG-CT)

International Nuclear Information System (INIS)

Matsuyama, Koukichi

1992-01-01

There are several useful diagnostic examinations for thyroid disease. The diagnostic value of CT in thyroid disease is still controvertial, although CT has become a routine clinical examination, since the plain CT does not always identify tumors accurately. In this paper, we introduce for the first time thyroid lymphography-computed tomography (TLG-CT) which may improve the diagnostic value of CT. The technique combines CT with thyroid lymphography. We performed TLG-CT in 92 patients with various thyroid diseases and 20 normal controls and classified the radiological features into the following 6 types: entire (normal thyroid); moth-eaten (Hashimoto's thyroiditis); defect (follicular adenoma and adenomatous goiter); lobate (papillary carcinoma); localized (various thyroid diseases); and extrathyroid defect (parathyroid tumor). In addition, we examined the relationship between TLG-CT type and the macroscopic appearance of the cut surface of the thyroid and lymph node metastasis in 20 patients with papillary carcinoma. The results suggest that papillary TLG-CT type carcinomas have a high incidence of lymph node metastasis. Our preliminary results suggest that TLG-CT is a potentially valuable diagnostic tool in the detection of thyroid disease and the assessment of the pathologic diagnosis as well as lymph node metastasis. (author)

[Accurate 3D free-form registration between fan-beam CT and cone-beam CT].

Science.gov (United States)

Liang, Yueqiang; Xu, Hongbing; Li, Baosheng; Li, Hongsheng; Yang, Fujun

2012-06-01

Because the X-ray scatters, the CT numbers in cone-beam CT cannot exactly correspond to the electron densities. This, therefore, results in registration error when the intensity-based registration algorithm is used to register planning fan-beam CT and cone-beam CT. In order to reduce the registration error, we have developed an accurate gradient-based registration algorithm. The gradient-based deformable registration problem is described as a minimization of energy functional. Through the calculus of variations and Gauss-Seidel finite difference method, we derived the iterative formula of the deformable registration. The algorithm was implemented by GPU through OpenCL framework, with which the registration time was greatly reduced. Our experimental results showed that the proposed gradient-based registration algorithm could register more accurately the clinical cone-beam CT and fan-beam CT images compared with the intensity-based algorithm. The GPU-accelerated algorithm meets the real-time requirement in the online adaptive radiotherapy.

CT scanning in pediatric head trauma: correlation of clinical features with CT scan diagnosis

International Nuclear Information System (INIS)

Arkoncel, Mary Ann P.; Posadas, Ma. Belen A.

1997-01-01

A retrospective review was conducted on 205 cases of pediatric head trauma for which cranial computed tomography scans were done at the Makati Medical Center, to determine which clinical features might positively predict an abnormality on CT scan. The clinical findings of loss of consciousness, GCS < 12, vomiting headache, seizures, and focal abnormalities on Neurologic Examination were significantly associated with abnormal findings on CT scan. However, a significant discrepancy does exist as to how accurately clinical findings do in fact predict normal and abnormal CT scan findings. Such a discrepancy allows us to conclude that a more liberal use of CT Scanning in cases of pediatric head trauma must be stressed to insure proper diagnosis. This study shows that when a patient presents with the aforementioned positive signs and symptoms, or with a focal neurologic deficit, or in combination, a 60-100 % positive prediction of abnormal CT Scan can be made. However, prediction of normal CT Scan is only 0-40%. (Author)

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... or nurse at the time of the CT examination. If your child has a known contrast material ... be given to your child for the CT examination. top of page What does the CT equipment ...

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is ... a CT scan. View full size with caption Pediatric Content Some imaging tests and treatments have special ...

CT diagnosis of acute spinal injury

International Nuclear Information System (INIS)

Ohhama, Mitsuru; Niimiya, Hikosuke; Kimura, Ko; Yamazaki, Gyoji; Nasu, Yoshiro; Shioya, Akihide

1982-01-01

CT pictures of 22 acute spinal injuries with damage of the spinal cord were evaluated. In the cases of spinal cord damage with bone injury, changes in the vertebral canal were fully observed by CT. In some of spinal cord damages without bone injury, narrowing of the vertebral canal was demonstrated by CT combined with CT myelography and reconstruction. Evaluation of CT number showed a high density area in damaged spinal cord in some cases. CT was thus considered to be useful as an adjunct diagnostic aid. (Ueda, J.)

Positron emission tomography/computed tomography (PET/CT) and CT for N staging of non-small cell lung cancer.

Science.gov (United States)

Vegar Zubović, Sandra; Kristić, Spomenka; Hadžihasanović, Besima

2017-08-01

Aim The aim of this study is to investigate the possibilities of non-invasive diagnostic imaging methods, positron emission tomography/computed tomography (PET/CT) and CT, in clinical N staging of non-small cell lung cancer (NSCLC). Methods Retrospective clinical study included 50 patients with diagnosed NSCLC who have undergone PET/CT for the purpose of disease staging. The International association for the study of lung cancer (IASLC) nodal mapping system was used for analysis of nodal disease. Data regarding CT N-staging and PET/CT Nstaging were recorded. Two methods were compared using χ2 test and Spearman rank correlation coefficient. Results Statistical analysis showed that although there were some differences in determining the N stage between CT and PET/CT, these methods were in significant correlation. CT and PET/CT findings established the same N stage in 74% of the patients. In five patients based on PET/CT findings the staging was changed from operable to inoperable, while in four patients staging was changed from inoperable to operable. Conclusion PET/CT and CT are noninvasive methods that can be reliably used for N staging of NSCLC. Copyright© by the Medical Assotiation of Zenica-Doboj Canton.

Volume-artifact reduction modality by helical CT of the anterior, middle and posterior carnial fossae. Comparison with conventional CT; Volumen-Artefakt-Reduktionstechnik mittels Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube. Vergleich mit der konventionellen kranialen CT

Energy Technology Data Exchange (ETDEWEB)

Dorenbeck, U.; Finkenzeller, T.; Hill, K.; Feuerbach, S.; Link, J. [Regensburg Univ. (Germany). Inst. fuer Roentgendiagnostik

2000-04-01

Purpose: The object of this study was to determine the extent to which a new volume-artifact reduction (VAR) modality using helical CT was able to reduce artifacts in the anterior, middle and posterior fossae in comparison with conventional CT (sequential mode). Methods: In a prospective, randomized trial, 50 patients underwent helical CT (VAR) and 50 underwent sequential CT. The results were evaluated by three radiologists; influences on image quality where scaled between 1 (no artifact) and 4 (not assessable). Eight regions of the anterior, middle and posterior fossae were evaluated. Results: On average, artifacts were scaled at 2.5 in helical CT (VAR) and 3.1 in conventional CT. Significant differences were seen at the eyeball, anterior to the petrosol bone, at the internal occipital crest, and at the level of the transverse sinus (p<0.005). Conclusions: Helical CT with the VAR modality is superior to conventional, sequential CT in the area of the anterior, middle and posterior fossae. (orig.) [German] Ziel: Das Ziel dieser Studie war herauszufinden, inwieweit ein neuer Volumen-Artefakt-Reduktionsmodus (VAR) im Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube gegenueber der Einzelschicht-CT zu einer Artefaktverringerung beitragen kann. Methoden: In einer prospektiven randomisierten Studie wurden 50 Untersuchungen mit Spiral-CT und 50 mit Einzelschicht-CT bezueglich Artefakten verglichen. Die Auswertung erfolgte durch drei Radiologen, die Bildqualitaet wurde in einer Skala zwischen 1 (kein Artefakt) und 4 (Beurteilung der Region wegen Artefakten nicht moeglich) angegeben. Acht anatomische Regionen in der vorderen, mittleren und hinteren Schaedelgrube wurden auf Beeintraechtigung durch Artefakte untersucht. Ergebnisse: Im Durchschnitt betrug die Bewertung fuer die Artefaktbeeintraechtigung beim Spiral-CT (VAR) 2,5 gegenueber 3,1 bei der Einzelschicht-CT. Der VAR-Modus ermoeglichte in der mittleren und hinteren Schaedelgrube sowie im Balbus oculi

Flat-detector computed tomography (FD-CT)

International Nuclear Information System (INIS)

Kalender, Willi A.; Kyriakou, Yiannis

2007-01-01

Flat-panel detectors or, synonymously, flat detectors (FDs) have been developed for use in radiography and fluoroscopy with the defined goal to replace standard X-ray film, film-screen combinations and image intensifiers by an advanced sensor system. FD technology in comparison to X-ray film and image intensifiers offers higher dynamic range, dose reduction, fast digital readout and the possibility for dynamic acquisitions of image series, yet keeping to a compact design. It appeared logical to employ FD designs also for computed tomography (CT) imaging. Respective efforts date back a few years only, but FD-CT has meanwhile become widely accepted for interventional and intra-operative imaging using C-arm systems. FD-CT provides a very efficient way of combining two-dimensional (2D) radiographic or fluoroscopic and 3D CT imaging. In addition, FD technology made its way into a number of dedicated CT scanner developments, such as scanners for the maxillo-facial region or for micro-CT applications. This review focuses on technical and performance issues of FD technology and its full range of applications for CT imaging. A comparison with standard clinical CT is of primary interest. It reveals that FD-CT provides higher spatial resolution, but encompasses a number of disadvantages, such as lower dose efficiency, smaller field of view and lower temporal resolution. FD-CT is not aimed at challenging standard clinical CT as regards to the typical diagnostic examinations; but it has already proven unique for a number of dedicated CT applications, offering distinct practical advantages, above all the availability of immediate CT imaging in the interventional suite or the operating room. (orig.)

Imaging and PET - PET/CT imaging

International Nuclear Information System (INIS)

Von Schulthess, G.K.; Hany, Th.F.

2008-01-01

PET/CT has grown because the lack of anatomic landmarks in PET makes 'hardware-fusion' to anatomic cross-sectional data extremely useful. Addition of CT to PET improves specificity, but also sensitivity, and adding PET to CT adds sensitivity and specificity in tumor imaging. The synergistic advantage of adding CT is that the attenuation correction needed for PET data can also be derived from the CT data. This makes PET-CT 25-30% faster than PET alone, leading to higher patient throughput and a more comfortable examination for patients typically lasting 20 minutes or less. FDG-PET-CT appears to provide relevant information in the staging and therapy monitoring of many tumors, such as lung carcinoma, colorectal cancer, lymphoma, gynaecological cancers, melanoma and many others, with the notable exception of prostatic cancer. for this cancer, choline derivatives may possibly become useful radiopharmaceuticals. The published literature on the applications of FDG-PET-CT in oncology is still limited but several designed studies have demonstrated the benefits of PET-CT. (authors)

CT of abdominal abscesses

International Nuclear Information System (INIS)

Korobkin, M.T.

1987-01-01

The imaging search for a suspected abdominal abscess is common in hospitalized patients, especially after recent abdominal surgery. This paper examines the role of CT in the detection, localization, and treatment of abdominal abscess. The accuracy, limitations, and technical aspects of CT in this clinical setting are discussed. The diagnosis of an abscess is based on the demonstration of a circumscribed abnormal fluid collection. Although percutaneous aspiration with gram stain and culture is usually indicated to differentiate abscess from other fluid collections, the CT-based detection of extraluminal gas bubbles makes the diagnosis of an abscess highly likely. CT is compared with conventional radiographic studies, US, and radio-nuclide imaging. Specific CT and clinical features of abscesses in the following sites are emphasized: subphrenic space, liver, pancreas, kidneys, psoas muscle, appendix, and colonic diverticula. Most abdominal abscesses can be successfully treated with percutaneous drainage techniques. The techniques, results, and limitations of percutaneous abscess drainage are reviewed

CT of tracheal agenesis

International Nuclear Information System (INIS)

Strouse, Peter J.; Hernandez, Ramiro J.; Newman, Beverley

2006-01-01

Tracheal agenesis is a rare and usually lethal anomaly. In the past, opaque contrast medium was injected via the esophagus to demonstrate the anatomy. To demonstrate the utility of helical and multidetector CT in delineating the aberrant anatomy in newborns with tracheal agenesis. Four newborns with tracheal agenesis were identified from three institutions. Imaging studies and medical records were reviewed. Each child was imaged with chest radiography. One child was imaged on a single-detector helical CT scanner and the other three on multidetector scanners. Helical and multidetector CT with 2D and 3D reconstructions clearly delineated the aberrant tracheobronchial and esophageal anatomy in each infant. Minimum intensity projection reformatted CT images were particularly helpful. One infant each had type I and type II tracheal agenesis. Two infants had type III tracheal agenesis. All four infants died. CT is a useful tool for delineating the aberrant anatomy of newborns with tracheal agenesis and thus helps in making rational clinical decisions. (orig.)

Head trauma and CT

International Nuclear Information System (INIS)

Samejima, Kanji; Yoshii, Nobuo; Tobari, Chitoshi

1979-01-01

In our cases of acute and subacute subdural hematoma, the use of CT was evaluated. In our department of surgery, acute subdural hematoma was found in 46 of 388 patients of head trauma who underwent CT. Acute subdural hematoma, like epidural hematoma was usually visualized as a high-density area along the cranial inner table, and this was easily differenciated from epidural hematoma because of difference in shape from the other. The picture of acute subdural hematoma was occasionally confused with that of intracerebral hematoma or cerebral contusion. Single use of CT does not differenciate subacute subdural hematoma from chronic subdural hematoma. However, CT usually visualized acute hematoma as a high-density area, showing the extent of hematoma. Comparison of the thickness of hematoma with the axis deviation of the median part such as the 3rd cerebral ventricle suggested severity of cerebral edema. CT also revealed bilateral or multiple lesions of cerebral contusion or intracerebral hematoma. (Ueda, J.)

CT of laryngeal trauma

International Nuclear Information System (INIS)

Jeffrey, R.B.

1986-01-01

Computed tomography has made a significant contribution to the radiologic assessment of the injured larynx. CT is an accurate, noninvasive modality that can rapidly diagnose both soft tissue and cartilaginous injuries. CT of the larynx involves a minimal degree of patient manipulation and discomfort and can be performed in conjunction with CT evaluation of intracranial or facial injuries. Conventional radiologic studies (anteroposterior and lateral soft tissue films of the neck, tomograms, or xerograms) are capable of demonstrating some cartilaginous fractures but are of limited value in defining the extent of soft tissue injury. In the acute trauma setting, laryngography is often technically difficult to perform because of patient discomfort and inability to cooperate. Although the overall experience is somewhat limited, CT appears to overcome many of the limitations of these conventional radiologic methods. The following is a discussion of the role of CT scanning in evaluating injuries to the larynx and cervical soft tissues

Congenital bronchopulmonary malformation: CT histopathological correlation.

Science.gov (United States)

Kyncl, Martin; Koci, Martin; Ptackova, Lea; Hornofova, Ludmila; Ondrej, Fabian; Snajdauf, Jiri; Pychova, Marcela

2016-12-01

This study evaluated the accuracy of postnatal computed tomography (CT) imaging in the identification of congenital bronchopulmonary malformation (BPM) in comparison with histopathological analysis. CT scans of prenatally diagnosed BPMs from 24 patients with available histology were analysed retrospectively. The CT images were reviewed blinded to histological findings by two radiologists. Specific diagnosis was assigned based on predetermined criteria. The accuracy of CT was evaluated. The agreement rate in CT diagnosis between two radiologists was 100%. In 75% the lesions were located in the lower lobes. An overlap of 71% in CT and histopathological diagnoses was reached. The least matching diagnosis was type 2 CPAM. Contrast enhanced chest CT is very accurate in characterizing the BPM spectrum and provides important information on lesion type and structure.

CT findings of inoperable lung carcinoma

International Nuclear Information System (INIS)

Gay, S.B.; Black, W.C.

1987-01-01

CT is useful in the evaluation of patients with newly diagnosed or highly suspected lung cancer. The principal role of CT is to screen those patients with metastatic disease beyond the hili from an attempt at curative thoracotomy. While CT is regarded as very sensitive, it is not considered highly specific, and thus a surgical procedure is usually recommended for definitive diagnosis of most ''positive'' CT findings. However, the authors demonstrate a few characteristic CT findings that are highly predictive of unresectable metastatic disease. These CT findings include massive mediastinal lymphadenopathy, diffuse mediastinal infiltration, pericardial involvement, vascular encasement, and advanced chest wall invasion

Thyroid lymphography-computed tomography (TLG-CT)

Energy Technology Data Exchange (ETDEWEB)

Matsuyama, Koukichi (Kansai Medical Univ., Moriguchi, Osaka (Japan))

1992-10-01

There are several useful diagnostic examinations for thyroid disease. The diagnostic value of CT in thyroid disease is still controvertial, although CT has become a routine clinical examination, since the plain CT does not always identify tumors accurately. In this paper, we introduce for the first time thyroid lymphography-computed tomography (TLG-CT) which may improve the diagnostic value of CT. The technique combines CT with thyroid lymphography. We performed TLG-CT in 92 patients with various thyroid diseases and 20 normal controls and classified the radiological features into the following 6 types: entire (normal thyroid); moth-eaten (Hashimoto's thyroiditis); defect (follicular adenoma and adenomatous goiter); lobate (papillary carcinoma); localized (various thyroid diseases); and extrathyroid defect (parathyroid tumor). In addition, we examined the relationship between TLG-CT type and the macroscopic appearance of the cut surface of the thyroid and lymph node metastasis in 20 patients with papillary carcinoma. The results suggest that papillary TLG-CT type carcinomas have a high incidence of lymph node metastasis. Our preliminary results suggest that TLG-CT is a potentially valuable diagnostic tool in the detection of thyroid disease and the assessment of the pathologic diagnosis as well as lymph node metastasis. (author).

CT diagnosis of hepatoma

Energy Technology Data Exchange (ETDEWEB)

Itai, Yuji [Tokyo Univ. (Japan). Faculty of Medicine

1982-04-01

In hepatocellular carcinoma, present status of CT diagnosis was discussed. Hepatocellular carcinoma is sometimes imaged in same concentration as that of surrounding tissues, and the detection rate ranged from 79 to 94%. The rate of differential diagnosis between primary and metastatic carcinoma was only 83% (includes 22% of false diagnosis) using contrast enhancement. The rates of detection of hepatocellular carcinoma and metastatic one were also only 87% and 75%, respectively, even by the combined use of arterial infusion CT and dynamic CT. However, the CT images is reproducible, and is supplemented by the information of US. Thus, the combination of these methods is useful in diagnosing the presence, extension, and nature of liver carcinoma.

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... What is Children's CT? What are some common uses of the procedure? How should we prepare for the CT scan? What does the CT equipment look like? How does the procedure work? How is the procedure performed? What will my ...

The role of CT in diagnosing small hepatic tumors; Usefulness of table incremental dynamic CT (ICT)