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Sample records for 3d ct colonography

  1. CT Colonography (Virtual Colonoscopy)

    MedlinePlus

    ... Z CT Colonography Computed tomography (CT) colonography or virtual colonoscopy uses special x-ray equipment to examine ... and blood vessels. CT colonography, also known as virtual colonoscopy, uses low dose radiation CT scanning to ...

  2. Three-dimensional display modes for CT colonography: conventional 3D virtual colonoscopy versus unfolded cube projection.

    PubMed

    Vos, Frans M; van Gelder, Rogier E; Serlie, Iwo W O; Florie, Jasper; Nio, C Yung; Glas, Afina S; Post, Frits H; Truyen, Roel; Gerritsen, Frans A; Stoker, Jaap

    2003-09-01

    The authors compared a conventional two-directional three-dimensional (3D) display for computed tomography (CT) colonography with an alternative method they developed on the basis of time efficiency and surface visibility. With the conventional technique, 3D ante- and retrograde cine loops were obtained (hereafter, conventional 3D). With the alternative method, six projections were obtained at 90 degrees viewing angles (unfolded cube display). Mean evaluation time per patient with the conventional 3D display was significantly longer than that with the unfolded cube display. With the conventional 3D method, 93.8% of the colon surface came into view; with the unfolded cube method, 99.5% of the colon surface came into view. Sensitivity and specificity were not significantly different between the two methods. Agreements between observers were kappa = 0.605 for conventional 3D display and kappa = 0.692 for unfolded cube display. Consequently, the latter method enhances the 3D endoluminal display with improved time efficiency and higher surface visibility.

  3. Matching 3-D prone and supine CT colonography scans using graphs.

    PubMed

    Wang, Shijun; Petrick, Nicholas; Van Uitert, Robert L; Periaswamy, Senthil; Wei, Zhuoshi; Summers, Ronald M

    2012-07-01

    In this paper, we propose a new registration method for prone and supine computed tomographic colonography scans using graph matching. We formulate 3-D colon registration as a graph matching problem and propose a new graph matching algorithm based on mean field theory. In the proposed algorithm, we solve the matching problem in an iterative way. In each step, we use mean field theory to find the matched pair of nodes with highest probability. During iterative optimization, one-to-one matching constraints are added to the system in a step-by-step approach. Prominent matching pairs found in previous iterations are used to guide subsequent mean field calculations. The proposed method was found to have the best performance with smallest standard deviation compared with two other baseline algorithms called the normalized distance along the colon centerline (NDACC) ( p = 0.17) with manual colon centerline correction and spectral matching ( p < 1e-5). A major advantage of the proposed method is that it is fully automatic and does not require defining a colon centerline for registration. For the latter NDACC method, user interaction is almost always needed for identifying the colon centerlines.

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

    SciTech Connect

    Yang Xiaoyun; Slabaugh, Greg

    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.

  5. Prior Image Constrained Compressed Sensing Metal Artifact Reduction (PICCS-MAR): 2D and 3D Image Quality Improvement with Hip Prostheses at CT Colonography

    PubMed Central

    Bannas, Peter; Li, Yinsheng; Motosugi, Utaroh; Li, Ke; Lubner, Meghan; Chen, Guang-Hong; Pickhardt, Perry J.

    2015-01-01

    Purpose To assess the effect of the prior-image-constrained-compressed-sensing based metal-artefactreduction (PICCS-MAR) algorithm on streak artefact reduction and 2D and 3D-image quality improvement in patients with total hip arthroplasty (THA) undergoing CT colonography (CTC). Material and Methods PICCS-MAR was applied to filtered-back-projection (FBP)-reconstructed DICOM CTC-images in 52 patients with THA (unilateral, n=30; bilateral, n=22). For FBP and PICCS-MAR series, ROI-measurements of CT-numbers were obtained at predefined levels for fat, muscle, air, and the most severe artefact. Two radiologists independently reviewed 2D and 3D CTC-images and graded artefacts and image quality using a five-point-scale (1=severe streak/no-diagnostic confidence, 5=no streak/excellent image-quality, high-confidence). Results were compared using paired and unpaired t-tests, Wilcoxon signed-ranks and Mann-Whitney-tests. Results Streak artefacts and image quality scores for FBP versus PICCS-MAR 2D-images (median: 1 vs. 3 and 2 vs. 3, respectively) and 3D images (median: 2 vs. 4 and 3 vs. 4, respectively) showed significant improvement after PICCS-MAR (all P<.001). PICCS-MAR significantly improved the accuracy of mean CT numbers for fat, muscle and the area with the most severe artefact (all P<.001). Conclusion PICCS-MAR substantially reduces streak artefacts related to THA on DICOM images, thereby enhancing visualization of anatomy on 2D and 3D CTC images and increasing diagnostic confidence. PMID:26521266

  6. Errors in CT colonography.

    PubMed

    Trilisky, Igor; Ward, Emily; Dachman, Abraham H

    2015-10-01

    CT colonography (CTC) is a colorectal cancer screening modality which is becoming more widely implemented and has shown polyp detection rates comparable to those of optical colonoscopy. CTC has the potential to improve population screening rates due to its minimal invasiveness, no sedation requirement, potential for reduced cathartic examination, faster patient throughput, and cost-effectiveness. Proper implementation of a CTC screening program requires careful attention to numerous factors, including patient preparation prior to the examination, the technical aspects of image acquisition, and post-processing of the acquired data. A CTC workstation with dedicated software is required with integrated CTC-specific display features. Many workstations include computer-aided detection software which is designed to decrease errors of detection by detecting and displaying polyp-candidates to the reader for evaluation. There are several pitfalls which may result in false-negative and false-positive reader interpretation. We present an overview of the potential errors in CTC and a systematic approach to avoid them.

  7. Prior Image Constrained Compressed Sensing Metal Artifact Reduction (PICCS-MAR): 2D and 3D Image Quality Improvement with Hip Prostheses at CT Colonography.

    PubMed

    Bannas, Peter; Li, Yinsheng; Motosugi, Utaroh; Li, Ke; Lubner, Meghan; Chen, Guang-Hong; Pickhardt, Perry J

    2016-07-01

    To assess the effect of the prior-image-constrained-compressed-sensing-based metal-artefact-reduction (PICCS-MAR) algorithm on streak artefact reduction and 2D and 3D-image quality improvement in patients with total hip arthroplasty (THA) undergoing CT colonography (CTC). PICCS-MAR was applied to filtered-back-projection (FBP)-reconstructed DICOM CTC-images in 52 patients with THA (unilateral, n = 30; bilateral, n = 22). For FBP and PICCS-MAR series, ROI-measurements of CT-numbers were obtained at predefined levels for fat, muscle, air, and the most severe artefact. Two radiologists independently reviewed 2D and 3D CTC-images and graded artefacts and image quality using a five-point-scale (1 = severe streak/no-diagnostic confidence, 5 = no streak/excellent image-quality, high-confidence). Results were compared using paired and unpaired t-tests and Wilcoxon signed-rank and Mann-Whitney-tests. Streak artefacts and image quality scores for FBP versus PICCS-MAR 2D-images (median: 1 vs. 3 and 2 vs. 3, respectively) and 3D images (median: 2 vs. 4 and 3 vs. 4, respectively) showed significant improvement after PICCS-MAR (all P < 0.001). PICCS-MAR significantly improved the accuracy of mean CT numbers for fat, muscle and the area with the most severe artefact (all P < 0.001). PICCS-MAR substantially reduces streak artefacts related to THA on DICOM images, thereby enhancing visualization of anatomy on 2D and 3D CTC images and increasing diagnostic confidence. • PICCS-MAR significantly reduces streak artefacts associated with total hip arthroplasty on 2D and 3D CTC. • PICCS-MAR significantly improves 2D and 3D CTC image quality and diagnostic confidence. • PICCS-MAR can be applied retrospectively to DICOM images from single-kVp CT.

  8. CT Colonography: Pitfalls in Interpretation

    PubMed Central

    Pickhardt, Perry J.; Kim, David H.

    2012-01-01

    Synopsis As with any radiologic imaging test, there are a number of potential interpretive pitfalls at CT colonography (CTC) that need to be recognized and handled appropriately. Perhaps the single most important step in learning to avoid most of these diagnostic traps is simply to be aware of their existence. With a little experience, most of these potential pitfalls will be easily recognized. This review will systematically cover the key pitfalls confronting the radiologist at CTC interpretation, primarily dividing them into those related to technique and those related to underlying anatomy. Tips and pointers for how to effectively handle these potential pitfalls are included. PMID:23182508

  9. [CT colonography - evolution of methodology and indications].

    PubMed

    Opletal, P; Standara, M

    2012-01-01

    Advances in CT scanners technology and computing in 90s allowed visual reconstruction of hollow organs inner surface. This method which was mainly used for colon wall imaging had to deal with several limitations from the very first years caused by poorly developed methodology of colonic preparation and distension as well as high radiation exposure. Aim of the paper is to provide an overview of technical and methodological innovations that can at least partially overcome above mentioned shortcomings. Due to these changes, CT colonography became the recognized method after incomplete or impossible optical colonography. Specific patient subgroups which particularly benefit from this modality and unresolved role of the CT colonography in colorectal cancer screening are also mentioned. CT colonography is a relatively new method that can not completely replace optical colonoscopy. Thanks to advances in technology, however, it became a valid diagnostic tool with certain advantages over other imaging or invasive methods. These benefits can be handed over to a patient when the examination is carefully indicated.

  10. Clinical experience with CT colonography

    NASA Astrophysics Data System (ADS)

    Reed, Judd E.; Garry, John L.; Wilson, Lynn A.; Johnson, C. Daniel

    2000-04-01

    Since the introduction of Computed Tomographic Colonography (CTC) in 1995, many advances in computer equipment and software have become available. Despite these advances, the promise of colon cancer prevention has not been realized. A colorectal screening tool that performs at a high level, is acceptable to patients, and can be performed safely and at low cost holds promise of saving lives in the future. Our institution has performed over two hundred seventy five clinical CTC examinations. These scans, which each entail a supine and a prone acquisition, only differ from our research protocol in the necessity of an expeditious interpretation. Patients arrive for their CTC examination early in the morning following a period of fasting and bowel preparation. If a CTC examination has a positive finding, the patient is scheduled for colonoscopic polypectomy that same morning. To facilitate this, the patients are required to continue fasting until the CTC examination has been interpreted. It is therefore necessary to process the CTC examination very quickly to minimize patient discomfort. A positive CTC result occurred in fifteen percent of examinations. Among these positive results, the specificity has been in excess of ninety five percent. Additionally, life threatening extra-colonic lesions were discovered in two percent of the screened population.

  11. Missed Lesions at CT Colonography: Lessons Learned

    PubMed Central

    Pickhardt, Perry J.

    2017-01-01

    Misinterpretation at CT colonography (CTC) can result in either a colorectal lesion being missed (false negative) or a false-positive diagnosis. This review will largely focus on potential missed lesions – and ways to avoid such misses. The general causes of false-negative interpretation at CTC can be broadly characterized and grouped into discrete categories related to suboptimal study technique, specific lesion characteristics, anatomic location, and imaging artifacts. Overlapping causes further increase the likelihood of missing a clinically relevant lesion. In the end, if the technical factors of bowel preparation, colonic distention, and robust CTC software are adequately addressed on a consistent basis, and the reader is aware of all the potential pitfalls at CTC, important lesions will seldom be missed. PMID:22539045

  12. CT colonography without cathartic preparation: feasibility study.

    PubMed

    Callstrom, M R; Johnson, C D; Fletcher, J G; Reed, J E; Ahlquist, D A; Harmsen, W S; Tait, K; Wilson, L A; Corcoran, K E

    2001-06-01

    To evaluate methods for contrast material labeling of stool in the unprepared colon for computed tomographic (CT) colonography and to determine their sensitivity for polyp detection. Fifty-six patients with suspected or known polyps were assigned to five groups. Two to seven doses of 225 mL of dilute contrast material were orally administered during 24 or 48 hours. Transverse CT images were assessed for effectiveness of stool labeling. Colonoscopy was performed in all patients and was the standard. Two radiologists blinded to prior imaging and colonoscopic results assessed polyp detection. For each group, average stool labeling scores and ranges were as follows: 24 hour two dose, 16% and 8%-21%; 24 hour five dose, 53% and 27%-66%; 48 hour four dose, 38% and 22%-48%; 48 hour six dose, 68% and 54%-77%; and 48 hour seven dose, 88% and 75%-98%. Sensitivity for the two radiologists for the identification of patients with polyps 1 cm or larger for each group was as follows: 24 hour two dose, 50% and 67%; 24 hour five dose, 100% and 100%; 48 hour four dose, 58% and 75%; 48 hour six dose, 56% and 67%; and 48 hour seven dose, 100% and 80%. Ingestion of contrast material adequately labels stool for lesion identification; a 48-hour lead time and multiple doses of contrast material are required. Sensitivity for polyp detection in patients with adequate stool labeling approaches the sensitivity for polyp detection in prepared colons.

  13. Adoption of CT colonography by US hospitals.

    PubMed

    McHugh, Megan; Osei-Anto, Awo; Klabunde, Carrie N; Galen, Barbara A

    2011-03-01

    Computed tomographic colonography (CTC) is a new noninvasive technology proposed as an option for colorectal cancer screening. The purpose of this study was to identify the percentage of US hospitals that offered CTC between 2005 and 2008 and factors that motivated or impeded adoption. Data on the provision of colorectal cancer screening services by nonfederal, general hospitals were analyzed using the 2005 to 2008 American Hospital Association annual surveys. Additionally, in 2009, exploratory interviews were conducted with representatives from radiology departments at 9 hospitals; 6 that provided CTC and 3 that did not. In 2008, 17% of hospitals offered CTC, up from 13% in 2005. Sixty-nine percent of hospitals that offered CTC in 2008 also offered optical colonoscopy services. Factors motivating the adoption of CTC included a desire to provide an alternative screening option for frail, elderly patients and patients with failed optical colonoscopy; long waits for optical colonoscopy; and promising evidence on CTC published in peer-reviewed literature. Lack of reimbursement was a commonly cited barrier. Growth of CT colonographic services at US hospitals occurred even in the absence of Medicare coverage or agreement among national guideline-setting organizations regarding CTC's use in screening. Almost one-third of hospitals that offer CTC do not offer optical colonoscopy and may not be prepared to provide adequate follow-up for patients with failed CTC. Copyright © 2011 American College of Radiology. All rights reserved.

  14. Automated synthesis, insertion and detection of polyps for CT colonography

    NASA Astrophysics Data System (ADS)

    Sezille, Nicolas; Sadleir, Robert J. T.; Whelan, Paul F.

    2003-03-01

    CT Colonography (CTC) is a new non-invasive colon imaging technique which has the potential to replace conventional colonoscopy for colorectal cancer screening. A novel system which facilitates automated detection of colorectal polyps at CTC is introduced. As exhaustive testing of such a system using real patient data is not feasible, more complete testing is achieved through synthesis of artificial polyps and insertion into real datasets. The polyp insertion is semi-automatic: candidate points are manually selected using a custom GUI, suitable points are determined automatically from an analysis of the local neighborhood surrounding each of the candidate points. Local density and orientation information are used to generate polyps based on an elliptical model. Anomalies are identified from the modified dataset by analyzing the axial images. Detected anomalies are classified as potential polyps or natural features using 3D morphological techniques. The final results are flagged for review. The system was evaluated using 15 scenarios. The sensitivity of the system was found to be 65% with 34% false positive detections. Automated diagnosis at CTC is possible and thorough testing is facilitated by augmenting real patient data with computer generated polyps. Ultimately, automated diagnosis will enhance standard CTC and increase performance.

  15. Automatic colon segmentation with dual scan CT colonography.

    PubMed

    Li, Hong; Santago, Peter

    2005-03-01

    We present a fully automated three-dimensional (3-D) segmentation algorithm to extract the colon lumen surface in CT colonography. Focusing on significant-size polyp detection, we target at an efficient algorithm that maximizes overall colon coverage, minimizes the extracolonic components, maintains local shape accuracy, and achieves high segmentation speed. Two-dimensional (2-D) image processing techniques are employed first, resulting in automatic seed placement and better colon coverage. This is followed by near-air threshold 3-D region-growing using an improved marching-cubes algorithm, which provides fast and accurate surface generation. The algorithm constructs a well-organized vertex-triangle structure that uniquely employs a hash table method, yielding an order of magnitude speed improvement. We segment two scans, prone and supine, independently and with the goal of improved colon coverage. Both segmentations would be available for subsequent polyp detection systems. Segmenting and analyzing both scans improves surface coverage by at least 6% over supine or prone alone. According to subjective evaluation, the average coverage is about 87.5% of the entire colon. Employing near-air threshold and elongation criteria, only 6% of the data sets include extracolonic components (EC) in the segmentation. The observed surface shape accuracy of the segmentation is adequate for significant-size (6 mm) polyp detection, which is also verified by the results of the prototype detection algorithm. The segmentation takes less than 5 minutes on an AMD 1-GHz single-processor PC, which includes reading the volume data and writing the surface results. The surface-based segmentation algorithm is practical for subsequent polyp detection algorithms in that it produces high coverage, has a low EC rate, maintains local shape accuracy, and has a computational efficiency that makes real-time polyp detection possible. A fully automatic or computer-aided polyp detection system using this

  16. Sub-milliSievert (sub-mSv) CT Colonography

    PubMed Central

    Lubner, Meghan G.; Pooler, B. Dustin; Kitchin, Douglas R.; Tang, Jie; Li, Ke; Kim, David H.; del Rio, Alejandro Munoz; Chen, Guang-Hong; Pickhardt, Perry J.

    2015-01-01

    Objective To prospectively compare reduced-dose (RD) CT colonography (CTC) with standard-dose (SD) imaging using several reconstruction algorithms. Methods 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, CTDIvol, 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. Results Mean CTDIvol 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). Conclusion 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. PMID:25903700

  17. Endoluminal surface registration for CT colonography using haustral fold matching☆

    PubMed Central

    Hampshire, Thomas; Roth, Holger R.; Helbren, Emma; Plumb, Andrew; Boone, Darren; Slabaugh, Greg; Halligan, Steve; Hawkes, David J.

    2013-01-01

    Computed Tomographic (CT) colonography is a technique used for the detection of bowel cancer or potentially precancerous polyps. The procedure is performed routinely with the patient both prone and supine to differentiate fixed colonic pathology from mobile faecal residue. Matching corresponding locations is difficult and time consuming for radiologists due to colonic deformations that occur during patient repositioning. We propose a novel method to establish correspondence between the two acquisitions automatically. The problem is first simplified by detecting haustral folds using a graph cut method applied to a curvature-based metric applied to a surface mesh generated from segmentation of the colonic lumen. A virtual camera is used to create a set of images that provide a metric for matching pairs of folds between the prone and supine acquisitions. Image patches are generated at the fold positions using depth map renderings of the endoluminal surface and optimised by performing a virtual camera registration over a restricted set of degrees of freedom. The intensity difference between image pairs, along with additional neighbourhood information to enforce geometric constraints over a 2D parameterisation of the 3D space, are used as unary and pair-wise costs respectively, and included in a Markov Random Field (MRF) model to estimate the maximum a posteriori fold labelling assignment. The method achieved fold matching accuracy of 96.0% and 96.1% in patient cases with and without local colonic collapse. Moreover, it improved upon an existing surface-based registration algorithm by providing an initialisation. The set of landmark correspondences is used to non-rigidly transform a 2D source image derived from a conformal mapping process on the 3D endoluminal surface mesh. This achieves full surface correspondence between prone and supine views and can be further refined with an intensity based registration showing a statistically significant improvement (p < 0

  18. Endoluminal surface registration for CT colonography using haustral fold matching.

    PubMed

    Hampshire, Thomas; Roth, Holger R; Helbren, Emma; Plumb, Andrew; Boone, Darren; Slabaugh, Greg; Halligan, Steve; Hawkes, David J

    2013-12-01

    Computed Tomographic (CT) colonography is a technique used for the detection of bowel cancer or potentially precancerous polyps. The procedure is performed routinely with the patient both prone and supine to differentiate fixed colonic pathology from mobile faecal residue. Matching corresponding locations is difficult and time consuming for radiologists due to colonic deformations that occur during patient repositioning. We propose a novel method to establish correspondence between the two acquisitions automatically. The problem is first simplified by detecting haustral folds using a graph cut method applied to a curvature-based metric applied to a surface mesh generated from segmentation of the colonic lumen. A virtual camera is used to create a set of images that provide a metric for matching pairs of folds between the prone and supine acquisitions. Image patches are generated at the fold positions using depth map renderings of the endoluminal surface and optimised by performing a virtual camera registration over a restricted set of degrees of freedom. The intensity difference between image pairs, along with additional neighbourhood information to enforce geometric constraints over a 2D parameterisation of the 3D space, are used as unary and pair-wise costs respectively, and included in a Markov Random Field (MRF) model to estimate the maximum a posteriori fold labelling assignment. The method achieved fold matching accuracy of 96.0% and 96.1% in patient cases with and without local colonic collapse. Moreover, it improved upon an existing surface-based registration algorithm by providing an initialisation. The set of landmark correspondences is used to non-rigidly transform a 2D source image derived from a conformal mapping process on the 3D endoluminal surface mesh. This achieves full surface correspondence between prone and supine views and can be further refined with an intensity based registration showing a statistically significant improvement (p<0.001), and

  19. Quantification of distention in CT colonography: development and validation of three computer algorithms.

    PubMed

    Hung, Peter W; Paik, David S; Napel, Sandy; Yee, Judy; Jeffrey, R Brooke; Steinauer-Gebauer, Andreas; Min, Juno; Jathavedam, Ashwin; Beaulieu, Christopher F

    2002-02-01

    Three bowel distention-measuring algorithms for use at computed tomographic (CT) colonography were developed, validated in phantoms, and applied to a human CT colonographic data set. The three algorithms are the cross-sectional area method, the moving spheres method, and the segmental volume method. Each algorithm effectively quantified distention, but accuracy varied between methods. Clinical feasibility was demonstrated. Depending on the desired spatial resolution and accuracy, each algorithm can quantitatively depict colonic diameter in CT colonography.

  20. Haustral fold detection method for CT colonography based on difference filter along colon centerline

    NASA Astrophysics Data System (ADS)

    Oda, Masahiro; Kitasaka, Takayuki; Mori, Kensaku; Suenaga, Yasuhito; Takayama, Tetsuji; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi; Nawano, Shigeru

    2009-02-01

    This paper presents a haustral fold detection method from 3D abdominal CT images. CT colonography (CTC) or virtual colonoscopy is a new colon diagnostic method to examine the inside of the colon. CTC system can visualize the interior of the colon from any viewpoint and viewing direction based on CT images of a patient. Both the supine and the prone positions of CT images are used for colon diagnosis to improve sensitivity of lesion detection. Registration of the supine and the prone positions of a patient is needed to improve efficiency of diagnosis using CT images in the two positions. Positions of haustral folds are utilizable as landmarks to establish correspondence between these two positions. We present a haustral fold detection method for registration of the supine and the prone positions. Haustral folds protrude almost perpendicular to a centerline of the colon. We designed new difference filter of CT values that can detect haustral folds. The difference filter calculates difference values of CT values along the colon centerline. It outputs high values in the haustral folds. False positive elimination is performed using two feature values including output value of the difference filter and volume of connected component. As the results of experiments using 12 cases of CT images, we confirmed that the proposed method can detect haustral folds satisfactorily. From evaluation using haustral folds >~ 3 [mm] in height and thickness, sensitivity of our method was 90.8% with 6.1 FPs/case.

  1. Informatics in radiology: Electronic cleansing for noncathartic CT colonography: a structure-analysis scheme.

    PubMed

    Cai, Wenli; Yoshida, Hiroyuki; Zalis, Michael E; Näppi, Janne Johannes; Harris, Gordon J

    2010-05-01

    Computed tomographic (CT) colonography performed after tagging of fecal matter but without a cathartic agent, or noncathartic CT colonography (also known as laxative-free CT colonography), is regarded as a promising next-generation technique for reducing or eliminating the discomfort associated with cathartic bowel preparation, which is the major barrier to undergoing colon cancer screening. Electronic cleansing is an emerging technique for the removal of tagged fecal materials from CT colonographic images. Three major electronic cleansing artifacts--soft-tissue degradation, pseudo-soft-tissue structures, and incomplete cleansing--severely impair the quality of electronically cleansed noncathartic CT colonographic images and limit the diagnostic utility of this modality. A structure-analysis electronic cleansing scheme was developed that makes use of local morphologic information to identify submerged colonic soft-tissue structures while removing the tagged material. Combined with other cutting-edge image processing techniques, including local roughness analysis, mosaic decomposition, and level set segmentation, structure-analysis cleansing helps eliminate the aforementioned artifacts, providing diagnostic-quality cleansed CT colonographic images for the detection of colon cancer. Noncathartic CT colonography with the application of structure-analysis cleansing is expected to help promote CT colonography as a patient-friendly method of colorectal cancer screening.

  2. Insurance Coverage for CT Colonography Screening: Impact on Overall Colorectal Cancer Screening Rates.

    PubMed

    Smith, Maureen A; Weiss, Jennifer M; Potvien, Aaron; Schumacher, Jessica R; Gangnon, Ronald E; Kim, David H; Weeth-Feinstein, Lauren A; Pickhardt, Perry J

    2017-09-01

    Purpose To compare overall colorectal cancer (CRC) screening rates for patients who were eligible and due for CRC screening and who were with and without insurance coverage for computed tomographic (CT) colonography for CRC screening. Materials and Methods The institutional review board approved this retrospective cohort study, with a waiver of consent. This study used longitudinal electronic health record data from 2005 through 2010 for patients managed by one of the largest multispecialty physician groups in the United States. It included 33 177 patients under age 65 who were eligible and due for CRC screening and managed by the participating health system. Stratified Cox regression models provided propensity-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the relationship between CT colonography coverage and CRC screening. Results After adjustment, patients who had insurance coverage for CT colonography and were due for CRC screening had a 48% greater likelihood of being screened for CRC by any method compared with those without coverage who were due for CRC screening (HR, 1.48; 95% CI: 1.41, 1.55). Similarly, patients with CT colonography coverage had a greater likelihood of being screened with CT colonography (HR, 8.35; 95% CI: 7.11, 9.82) and with colonoscopy (HR, 1.38; 95% CI: 1.31, 1.45) but not with fecal occult blood test (HR, 1.00; 95% CI: 0.91, 1.10) than those without such insurance coverage. Conclusion Insurance coverage of CT colonography for CRC screening was associated with a greater likelihood of a patient being screened and a greater likelihood of being screened with a test that helps both to detect cancer and prevent cancer from developing (CT colonography or colonoscopy). (©) RSNA, 2017.

  3. Centerline-based colon segmentation for CAD of CT colonography

    NASA Astrophysics Data System (ADS)

    Näppi, Janne; Frimmel, Hans; Yoshida, Hiroyuki

    2006-03-01

    We developed a fast centerline-based segmentation (CBS) algorithm for the extraction of colon in computer-aided detection (CAD) for CT colonography (CTC). CBS calculates local centerpoints along thresholded components of abdominal air, and connects the centerpoints iteratively to yield a colon centerline. A thick region encompassing the colonic wall is extracted by use of region-growing around the centerline. The resulting colonic wall is employed in our CAD scheme for the detection of polyps, in which polyps are detected within the wall by use of volumetric shape features. False-positive detections are reduced by use of a Bayesian neural network. The colon extraction accuracy of CBS was evaluated by use of 38 clinical CTC scans representing various preparation conditions. On average, CBS covered more than 96% of the visible region of colon with less than 1% extracolonic components in the extracted region. The polyp detection performance of the CAD scheme was evaluated by use of 121 clinical cases with 42 colonoscopy-confirmed polyps 5-25 mm. At a 93% by-polyp detection sensitivity for polyps >=5 mm, a leave-one-patient-out evaluation yielded 1.4 false-positive polyp detections per CT scan.

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

    PubMed Central

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

    2010-01-01

    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 (p<0.05) by the two-step algorithm than by the one-step for 63% of all possible operating points. While operating at a suitable sensitivity level such as 90.8% (79/87) or 88.5% (77/87), the false positive rate was reduced by 24.4% (95% confidence intervals 17.9–31.0%) or 45.8% (95% confidence intervals 40.1–51.0%) respectively. We demonstrated that, with a proper experimental design, the Pareto optimization process can effectively help in fine-tuning and redesigning polyp detection algorithms. PMID:20548966

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

    PubMed

    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 < 0.001), image noise was significantly lower (both P < 0.001), whereas volume CT dose index was unchanged (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.

  6. Performance of CT Colonography for Detecting Small Diminutive and Flat Polyps

    DTIC Science & Technology

    2010-04-01

    following CRC surgery , Togashi and colleagues41 fol- lowed 500 polyps 6 mm or less over an average interval of 3.6 years. They concluded that this practice...00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Performance of CT Colonography for Detecting Small Diminutive and Flat Polyps 5a. CONTRACT NUMBER...98) Prescribed by ANSI Std Z39-18 Author’s personal copy Performance of CT Colonography for Detecting Small , Diminutive, and Flat Polyps Perry J

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

    PubMed

    Zueco Zueco, Carmen; Sobrido Sampedro, Carolina; Corroto, Juan D; Rodriguez Fernández, Paula; Fontanillo Fontanillo, Manuela

    2012-06-01

    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. • Computed tomographic colonography (CTC) without cathartic preparation is well accepted by patients • Cathartic-free faecal tagging CTC yields high positive predictive values • CTC without cathartic preparation could improve uptake of colorectal cancer screening.

  8. Association Between Visceral Adiposity and Colorectal Polyps on CT Colonography

    PubMed Central

    Summers, Ronald M.; Liu, Jiamin; Sussman, Daniel L.; Dwyer, Andrew J.; Rehani, Bhavya; Pickhardt, Perry J.; Choi, J. Richard; Yao, Jianhua

    2012-01-01

    OBJECTIVE To determine if there is an association between visceral adiposity measured on CT colonography (CTC) and colorectal polyps. MATERIALS AND METHODS The study was HIPAA-compliant and approved by our Institutional Review Board and Office of Human Subjects Research. 1186 patients who underwent CTC and same day optical colonoscopy were analyzed. Visceral adipose tissue volumes (VAV) and volume percents relative to total internal body volume (VAV%) were measured on slices in the L2–L3 regions on supine CTC scan with validated fully-automated software. Student t-test, odds ratio (OR), logistic regression and receiver operating characteristic analyses were performed. RESULTS For subjects with and without adenomatous polyps, means and s. d. of VAV% were 31.2 ± 10.8% (n=345) and 28.2% ± 11.3% (n=841) (p<0.0001), respectively. For subjects with and without hyperplastic polyps they were 31.8% ± 10.7% (n=244) and 28.3% ± 11.2% (n=942) (p<0.0001), respectively. Comparing the lowest and highest quintiles of VAV%, the ORs for having at least one adenomatous polyp or hyperplastic polyp versus no polyp were 2.06 (95% CI: 1.36–3.13) and 1.71 [1.08, 2.71] and the prevalence of having adenomatous polyps or hyperplastic polyps increased 14% and 8%, respectively. CONCLUSION Subjects with higher visceral adiposity measurements on CTC have a greater risk for the presence of colonic polyps. PMID:22733893

  9. Haustral loop extraction for CT colonography using geodesics.

    PubMed

    Liu, Yongkai; Duan, Chaijie; Liang, Jerome; Hu, Jing; Lu, Hongbing; Luo, Mingyue

    2017-03-01

    The human colon has complex geometric structures because of its haustral folds, which are thin flat protrusions on the colon wall. The haustral loop is the curve (approximately triangular in shape) that encircles the highly convex region of the haustral fold, and is regarded as the natural landmark of the colon, intersecting the longitude of the colon in the middle. Haustral loop extraction can assist in reducing the structural complexity of the colon, and the loops can also serve as anatomic markers for computed tomographic colonography (CTC). Moreover, haustral loop sectioning of the colon can help with the performance of precise prone-supine registration. We propose an accurate approach of extracting haustral loops for CT virtual colonoscopy based on geodesics. First, the longitudinal geodesic (LG) connecting the start and end points is tracked by the geodesic method and the colon is cut along the LG. Second, key points are extracted from the LG, after which paired points that are used for seeking the potential haustral loops are calculated according to the key points. Next, for each paired point, the shortest distance (geodesic line) between the paired points twice is calculated, namely one on the original surface and the other on the cut surface. Then, the two geodesics are combined to form a potential haustral loop. Finally, erroneous and nonstandard potential loops are removed. To evaluate the haustral loop extraction algorithm, we first utilized the algorithm to extract the haustral loops. Then, we let the clinicians determine whether the haustral loops were correct and then identify the missing haustral loops. The extraction algorithm successfully detected 91.87% of all of the haustral loops with a very low false positive rate. We believe that haustral loop extraction may benefit many post-procedures in CTC, such as supine-prone registration, computer-aided diagnosis, and taenia coli extraction.

  10. CT colonography after fecal tagging with a reduced cathartic cleansing and a reduced volume of barium.

    PubMed

    Lefere, Philippe; Gryspeerdt, Stefaan; Marrannes, Jesse; Baekelandt, Marc; Van Holsbeeck, Bartel

    2005-06-01

    The objective of our study was to assess the efficacy of fecal tagging with a small volume of barium in combination with a reduced cathartic cleansing before CT colonography. The study consists of a review of 200 patients examined in a clinical setting. Conventional colonoscopy and CT colonography or follow-up were used as the gold standard. All patients prepared for CT colonography the day before the examination with a dedicated low-residue diet. Fecal tagging was performed with 50 mL of barium. The residual feces and fluid were evaluated on a segmental basis. The residual feces was divided in two categories (< 6 mm and > or = 6 mm). The amount of fluid was assessed on the axial slices. The efficacy of tagging was evaluated visually. For the study, 1,200 segments were evaluated. Residual feces was present in 413 segments (34.41%), with feces less than 6 mm in 210 segments (17.5%) and feces 6 mm or greater in 203 segments (16.92%). There was residual fluid in 527 segments (43.91%). Nontagged feces 6 mm or greater was present in 49 segments (4.08%) and nontagged fluid in 178 segments (14.83%). All nontagged feces 6 mm or greater was easy to assess. All fluid redistributed with dual positioning. A total of 65 lesions 6 mm or greater were correctly diagnosed on primary CT colonography. In two patients, two lesions adjacent to each other were misinterpreted as being only one. Another 8-mm lesion was missed. In the present study, CT colonography after fecal tagging with 50 mL of barium combined with a reduced cathartic cleansing was feasible.

  11. Burden of colonoscopy compared to non-cathartic CT-colonography in a colorectal cancer screening programme: randomised controlled trial.

    PubMed

    de Wijkerslooth, Thomas R; de Haan, Margriet C; Stoop, Esther M; Bossuyt, Patrick M; Thomeer, Maarten; Essink-Bot, Marie-Louise; van Leerdam, Monique E; Fockens, Paul; Kuipers, Ernst J; Stoker, Jaap; Dekker, Evelien

    2012-11-01

    CT-colonography has been suggested to be less burdensome for primary colorectal cancer (CRC) screening than colonoscopy. To compare the expected and perceived burden of both in a randomised trial. 8844 Dutch citizens aged 50-74 years were randomly invited for CRC screening with colonoscopy (n=5924) or CT-colonography (n=2920). Colonoscopy was performed after full colon lavage, or CT-colonography after limited bowel preparation (non-cathartic). All invitees were asked to complete the expected burden questionnaire before the procedure. All participants were invited to complete the perceived burden questionnaire 14 days later. Mean scores were calculated on 5-point scales. Expected burden: 2111 (36%) colonoscopy and 1199 (41%) CT-colonography invitees completed the expected burden questionnaire. Colonoscopy invitees expected the bowel preparation and screening procedure to be more burdensome than CT-colonography invitees: mean scores 3.0±1.1 vs 2.3±0.9 (p<0.001) and 3.1±1.1 vs 2.2±0.9 (p<0.001). Perceived burden: 1009/1276 (79%) colonoscopy and 801/982 (82%) CT-colonography participants completed the perceived burden questionnaire. The full screening procedure was reported as more burdensome in CT-colonography than in colonoscopy: 1.8±0.9 vs 2.0±0.9 (p<0.001). Drinking the bowel preparation resulted in a higher burden score in colonoscopy (3.0±1.3 vs 1.7±1.0, p<0.001) while related bowel movements were scored more burdensome in CT-colonography (2.0±1.0 vs 2.2±1.1, p<0.001). Most participants would probably or definitely take part in a next screening round: 96% for colonoscopy and 93% for CT-colonography (p=0.99). In a CRC screening programme, colonoscopy invitees expected the screening procedure and bowel preparation to be more burdensome than CT-colonography invitees. In participants, CT-colonography was scored as more burdensome than colonoscopy. Intended participation in a next screening round was comparable.

  12. CT colonography: patient tolerance of laxative free fecal tagging regimen versus traditional cathartic cleansing.

    PubMed

    Buccicardi, Duccio; Grosso, Massimo; Caviglia, Ilaria; Gastaldo, Alessandro; Carbone, Sabrina; Neri, Emanuele; Bartolozzi, Carlo; Quadri, Piergiorgio

    2011-10-01

    The aim of our prospective study was to compare patient tolerance of laxative free fecal tagging regimen (LFT) versus traditional cathartic cleansing (TC). 264 patients, at average risk for development of colorectal cancer (105 men and 159 women; mean age 62 years ± 5 SD), underwent 32 rows CT colonography. Patients were alternatively placed into 2 study groups: Group 1 (n = 132) followed TC and Group 2 (n = 132) LFT. TC protocol consisted of no fiber diet and Phospho-lax(®) 80 mL in 2 L of water the day before imaging. LFT protocol consisted of no fiber diet and ingestion with meals of 30 mL of water-soluble iodinated contrast agent (Gastrografin(®)) for 2 days before imaging. No frank laxative drugs were administered. All studies were reviewed in a combined fashion, primary 2D followed by 3D endoluminal and dissected views. After the examination all patients were asked to provide a feedback about tolerance to the each bowel preparation. The first 30 patients of each group were also investigated with optical colonoscopy (OC) used as gold standard to confirm our diagnosis (Group 1* and Group 2*). LFT reduces discomfort and seems to improve diagnostic accuracy of CTC.

  13. Colorectal and extracolonic cancers detected at screening CT colonography in 10,286 asymptomatic adults.

    PubMed

    Pickhardt, Perry J; Kim, David H; Meiners, Ryan J; Wyatt, Kimberly S; Hanson, Meghan E; Barlow, Duncan S; Cullen, Priscilla A; Remtulla, Rahim A; Cash, Brooks D

    2010-04-01

    To retrospectively determine the detection rates, clinical stages, and short-term patient survival for all unsuspected cancers identified at screening computed tomographic (CT) colonography, including both colorectal carcinoma (CRC) and extracolonic malignancies. From April 2004 through March 2008, prospective colorectal and extracolonic interpretation was performed in 10,286 outpatient adults (5388 men, 4898 women; mean age, 59.8 years) undergoing screening CT colonography at two centers in this institutional review board-approved, HIPAA-compliant study. For all histologically proved, clinically unsuspected cancers detected at CT colonography that were identified at retrospective review of the medical records, the stage of disease, treatment, and clinical outcome were analyzed. Benign neoplasms (including advanced colorectal adenomas), symptomatic lesions, and tumors without pathologic proof were excluded. Statistical analysis was performed with Fisher exact test and two-sample z test. Unsuspected cancer was confirmed in 58 (0.56%) patients (33 women, 25 men; mean age, 60.8 years), which included invasive CRC in 22 patients (0.21%) and extracolonic cancer in 36 patients (0.35%). Extracolonic malignancies included renal cell carcinoma (n = 11), lung cancer (n = 8), non-Hodgkin lymphoma (n = 6), and a variety of other tumors (n = 11). Cancers in 31 patients (53.4%) were stage I or localized. At the most recent clinical follow-up (mean, 30.0 months +/- 11.8 [standard deviation]; range, 12-56 months), three patients (5.2%) had died of their cancer. The overall detection rate of unsuspected cancer is approximately one per 200 asymptomatic adults undergoing routine screening CT colonography, including about one invasive CRC per 500 cases and one extracolonic cancer per 300 cases. Detection and treatment at an early presymptomatic stage may have contributed to the favorable outcome. RSNA, 2010

  14. Feasibility of automated matching of supine and prone CT-colonography examinations.

    PubMed

    de Vries, A H; Truyen, R; van der Peijl, J; Florie, J; van Gelder, R E; Gerritsen, F; Stoker, J

    2006-09-01

    Matching of prone and supine positions in CT colonography may improve accuracy of polyp detection. The purpose of this study was to investigate the feasibility of automatic prone-supine matching in CT-colonography using proven polyps as fixed points of reference. The method is based on similarities in the direction of centre-lines and allows for compression and extraction of the centre-lines in both positions. To illustrate the impact of the match error of the new method in practice, the visibility of the matched polyps in a primary three-dimensional unfolded cube setting was determined as well. The method was compared with a method that relies on the normalized distance along the centre-line (NDAC method). The median absolute match error was 14 mm (range 0-59 mm, average 20 mm) either proximal or distal from the actual polyp in prone position. In the observer study, 70% (26/37) of the polyps were directly visible in prone view. The overall difference in median absolute match error between both methods was small (2 mm), although half way along the centre-line there were polyps with substantial differences in match error (larger with NDAC). We concluded that automated prone-supine matching of CT-colonography studies is feasible and has a low match error. The difference with the NDAC method was small and not significant, although half way along the centre-line some differences were seen.

  15. CT Colonography with Computer-aided Detection: Recognizing the Causes of False-Positive Reader Results

    PubMed Central

    Dachman, Abraham H.; Wroblewski, Kristen; Vannier, Michael W.; Horne, John M.

    2014-01-01

    Computed tomography (CT) colonography is a screening modality used to detect colonic polyps before they progress to colorectal cancer. Computer-aided detection (CAD) is designed to decrease errors of detection by finding and displaying polyp candidates for evaluation by the reader. CT colonography CAD false-positive results are common and have numerous causes. The relative frequency of CAD false-positive results and their effect on reader performance on the basis of a 19-reader, 100-case trial shows that the vast majority of CAD false-positive results were dismissed by readers. Many CAD false-positive results are easily disregarded, including those that result from coarse mucosa, reconstruction, peristalsis, motion, streak artifacts, diverticulum, rectal tubes, and lipomas. CAD false-positive results caused by haustral folds, extracolonic candidates, diminutive lesions (<6 mm), anal papillae, internal hemorrhoids, varices, extrinsic compression, and flexural pseudotumors are almost always recognized and disregarded. The ileocecal valve and tagged stool are common sources of CAD false-positive results associated with reader false-positive results. Nondismissable CAD soft-tissue polyp candidates larger than 6 mm are another common cause of reader false-positive results that may lead to further evaluation with follow-up CT colonography or optical colonoscopy. Strategies for correctly evaluating CAD polyp candidates are important to avoid pitfalls from common sources of CAD false-positive results. ©RSNA, 2014 PMID:25384290

  16. Thin slice three dimentional (3D) reconstruction versus CT 3D reconstruction of human breast cancer

    PubMed Central

    Zhang, Yi; Zhou, Yan; Yang, Xinhua; Tang, Peng; Qiu, Quanguang; Liang, Yong; Jiang, Jun

    2013-01-01

    Background & objectives: With improvement in the early diagnosis of breast cancer, breast conserving therapy (BCT) is being increasingly used. Precise preoperative evaluation of the incision margin is, therefore, very important. Utilizing three dimentional (3D) images in a preoperative evaluation for breast conserving surgery has considerable significance, but the currently 3D CT scan reconstruction commonly used has problems in accurately displaying breast cancer. Thin slice 3D reconstruction is also widely used now to delineate organs and tissues of breast cancers. This study was aimed to compare 3D CT with thin slice 3D reconstruction in breast cancer patients to find a better technique for accurate evaluation of breast cancer. Methods: A total of 16-slice spiral CT scans and 3D reconstructions were performed on 15 breast cancer patients. All patients had been treated with modified radical mastectomy; 2D and 3D images of breast and tumours were obtained. The specimens were fixed and sliced at 2 mm thickness to obtain serial thin slice images, and reconstructed using 3D DOCTOR software to gain 3D images. Results: Compared with 2D CT images, thin slice images showed more clearly the morphological characteristics of tumour, breast tissues and the margins of different tissues in each slice. After 3D reconstruction, the tumour shapes obtained by the two reconstruction methods were basically the same, but the thin slice 3D reconstruction showed the tumour margins more clearly. Interpretation & conclusions: Compared with 3D CT reconstruction, thin slice 3D reconstruction of breast tumour gave clearer images, which could provide guidance for the observation and application of CT 3D reconstructed images and contribute to the accurate evaluation of tumours using CT imaging technology. PMID:23481052

  17. Opportunistic Osteoporosis Screening: Addition of Quantitative CT Bone Mineral Density Evaluation to CT Colonography.

    PubMed

    Ziemlewicz, Timothy J; Binkley, Neil; Pickhardt, Perry J

    2015-10-01

    For patients undergoing CT colonography (CTC), the screening presents an opportunity for concurrent osteoporosis screening, without increasing radiation exposure or the time involved for the patient, using proximal femur quantitative CT-CT x-ray absorptiometry (QCT-CTXA). This cohort included 129 women and 112 men (mean age: 60.1 ± 8.2 years; range: 50-95 years) who underwent CTC between March 2013 and September 2014. Areal bone mineral density (BMD; g/cm(2)), and resultant left femoral neck T-score, was prospectively measured on the supine CT series. QCT results were reported with the CTC. Chart review evaluated whether the patients were eligible for BMD screening according to guidelines from the US Preventive Services Task Force and the National Osteoporosis Foundation guidelines; whether they had undergone prior BMD testing; and whether QCT results changed patient management. Overall, 68.0% (164 of 241) of patients from this cohort had not previously undergone BMD screening. According to the National Osteoporosis Foundation guidelines, 44.0% (106 of 241) of patients were eligible for screening. T-scores within the osteopenic and osteoporotic range were detected in 32.3% (78 of 241) and 5.0% (12 of 241) of patients, respectively. Of these patients with low BMD, 66.7% (60 of 90) either had not previously undergone screening or were eligible for BMD testing. Reporting of QCT-CTXA T-scores altered management in 9 patients (3.7%) who had low BMD. Maximizing the pre-existing value from imaging studies is crucial in the current era of health care reform. We demonstrate that colorectal and osteoporosis screening can be combined at CT examination, adding clinical and likely economic value. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  18. Cost-effectiveness analysis of 3-D computerized tomography colonography versus optical colonoscopy for imaging symptomatic gastroenterology patients.

    PubMed

    Gomes, Manuel; Aldridge, Robert W; Wylie, Peter; Bell, James; Epstein, Owen

    2013-04-01

    When symptomatic gastroenterology patients have an indication for colonic imaging, clinicians have a choice between optical colonoscopy (OC) and computerized tomography colonography with three-dimensional reconstruction (3-D CTC). 3-D CTC provides a minimally invasive and rapid evaluation of the entire colon, and it can be an efficient modality for diagnosing symptoms. It allows for a more targeted use of OC, which is associated with a higher risk of major adverse events and higher procedural costs. A case can be made for 3-D CTC as a primary test for colonic imaging followed if necessary by targeted therapeutic OC; however, the relative long-term costs and benefits of introducing 3-D CTC as a first-line investigation are unknown. The aim of this study was to assess the cost effectiveness of 3-D CTC versus OC for colonic imaging of symptomatic gastroenterology patients in the UK NHS. We used a Markov model to follow a cohort of 100,000 symptomatic gastroenterology patients, aged 50 years or older, and estimate the expected lifetime outcomes, life years (LYs) and quality-adjusted life years (QALYs), and costs (£, 2010-2011) associated with 3-D CTC and OC. Sensitivity analyses were performed to assess the robustness of the base-case cost-effectiveness results to variation in input parameters and methodological assumptions. 3D-CTC provided a similar number of LYs (7.737 vs 7.739) and QALYs (7.013 vs 7.018) per individual compared with OC, and it was associated with substantially lower mean costs per patient (£467 vs £583), leading to a positive incremental net benefit. After accounting for the overall uncertainty, the probability of 3-D CTC being cost effective was around 60 %, at typical willingness-to-pay values of £20,000-£30,000 per QALY gained. 3-D CTC is a cost-saving and cost-effective option for colonic imaging of symptomatic gastroenterology patients compared with OC.

  19. A Case of Colon Cancer Associated with Ulcerative Colitis: Evaluation Using CT Colonography.

    PubMed

    Ichikawa, Tamaki; Sadahiro, Sotaro; Yuhara, Hiroki; Suzuki, Takayoshi; Igarashi, Muneki; Mine, Tetsuya; Tomita, Sakura; Imai, Yutaka

    2015-09-20

    A 29-year-old female with ulcerative colitis was found to have advanced sigmoid colon cancer on colonoscopy. Computed tomography (CT) was performed after colonoscopy for the evaluation of metastasis. CT colonography (CTC) could be understood adding carbon dioxide because of soon after colonoscopic examination. Images of CTC were evaluated by two- and three-dimensional images including virtual endoscopic, virtual colon dissection and air images, and then compared with conventional endoscopic images. Virtual endoscopic images of flat elevated cancer with shallow ulcer were similar to those findings by conventional endoscopy. This lesion could be depicted by computer-aided detection.

  20. Strategies for improved interpretation of computer-aided detections for CT colonography utilizing distributed human intelligence.

    PubMed

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

    2012-08-01

    Computer-aided detection (CAD) systems have been shown to improve the diagnostic performance of CT colonography (CTC) in the detection of premalignant colorectal polyps. Despite the improvement, the overall system is not optimal. CAD annotations on true lesions are incorrectly dismissed, and false positives are misinterpreted as true polyps. Here, we conduct an observer performance study utilizing distributed human intelligence in the form of anonymous knowledge workers (KWs) to investigate human performance in classifying polyp candidates under different presentation strategies. We evaluated 600 polyp candidates from 50 patients, each case having at least one polyp ≥6 mm, from a large database of CTC studies. Each polyp candidate was labeled independently as a true or false polyp by 20 KWs and an expert radiologist. We asked each labeler to determine whether the candidate was a true polyp after looking at a single 3D-rendered image of the candidate and after watching a video fly-around of the candidate. We found that distributed human intelligence improved significantly when presented with the additional information in the video fly-around. We noted that performance degraded with increasing interpretation time and increasing difficulty, but distributed human intelligence performed better than our CAD classifier for "easy" and "moderate" polyp candidates. Further, we observed numerous parallels between the expert radiologist and the KWs. Both showed similar improvement in classification moving from single-image to video interpretation. Additionally, difficulty estimates obtained from the KWs using an expectation maximization algorithm correlated well with the difficulty rating assigned by the expert radiologist. Our results suggest that distributed human intelligence is a powerful tool that will aid in the development of CAD for CTC.

  1. Noncathartic CT Colonography: Image Quality Assessment and Performance and in a Screening Cohort

    PubMed Central

    Fletcher, Joel G.; Silva, Alvin C.; Fidler, Jeff L.; Cernigliaro, Joseph G.; Manduca, Armando; Limburg, Paul J.; Wilson, Lynn A.; Engelby, Trudy A.; Spencer, Garrett; Harmsen, W. Scott; Mandrekar, Jay; Johnson, C. Daniel

    2014-01-01

    OBJECTIVE Cathartic bowel preparation is a major barrier for colorectal cancer screening. We examined noncathartic CT colonography (CTC) quality and performance using four similar bowel-tagging regimens in an asymptomatic screening cohort. SUBJECTS AND METHODS This prospective study included 564 asymptomatic subjects who underwent noncathartic CTC without dietary modification but with 21 g of barium with or without iodinated oral contrast material (four regimens). The quality of tagging with oral agents was evaluated. A gastrointestinal radiologist evaluated examinations using primary 2D search supplemented by electronic cleansing (EC) and 3D problem solving. Results were compared with complete colonoscopy findings after bowel purgation and with retrospective unblinded evaluation in 556 of the 564 (99%) subjects. RESULTS Of the 556 subjects, 7% (37/556) and 3% (16/556) of patients had 52 and 20 adenomatous polyps ≥ 6 and ≥ 10 mm, respectively. The addition of iodine significantly improved the percentage of labeled stool (p ≤ 0.0002) and specificity (80% vs 89–93%, respectively; p = 0.046). The overall sensitivity of noncathartic CTC for adenomatous polyps ≥ 6 mm was 76% (28/37; 95% CI, 59–88%), which is similar to the sensitivity of the iodinated regimens with most patients (sensitivity: 231 patients, 74% [14/19; 95% CI, 49–91%]; 229 patients, 80% [12/15; 95% CI, 52–96%]). The negative predictive value was 98% (481/490), and the lone cancer was detected (0.2%, 1/556). EC was thought to improve conspicuity of 10 of 21 visible polyps ≥ 10 mm. CONCLUSION In this prospective study of asymptomatic subjects, the per-patient sensitivity of noncathartic CTC for detecting adenomas ≥ 6 mm was approximately 76%. Inclusion of oral iodine contrast material improves examination specificity and the percentage of labeled stool. EC may improve polyp conspicuity. PMID:24059367

  2. Noncathartic CT colonography: Image quality assessment and performance and in a screening cohort.

    PubMed

    Fletcher, Joel G; Silva, Alvin C; Fidler, Jeff L; Cernigliaro, Joseph G; Manduca, Armando; Limburg, Paul J; Wilson, Lynn A; Engelby, Trudy A; Spencer, Garrett; Harmsen, W Scott; Mandrekar, Jay; Johnson, C Daniel

    2013-10-01

    Cathartic bowel preparation is a major barrier for colorectal cancer screening. We examined noncathartic CT colonography (CTC) quality and performance using four similar bowel-tagging regimens in an asymptomatic screening cohort. This prospective study included 564 asymptomatic subjects who underwent noncathartic CTC without dietary modification but with 21 g of barium with or without iodinated oral contrast material (four regimens). The quality of tagging with oral agents was evaluated. A gastrointestinal radiologist evaluated examinations using primary 2D search supplemented by electronic cleansing (EC) and 3D problem solving. Results were compared with complete colonoscopy findings after bowel purgation and with retrospective unblinded evaluation in 556 of the 564 (99%) subjects. Of the 556 subjects, 7% (37/556) and 3% (16/556) of patients had 52 and 20 adenomatous polyps ≥ 6 and ≥ 10 mm, respectively. The addition of iodine significantly improved the percentage of labeled stool (p ≤ 0.0002) and specificity (80% vs 89-93%, respectively; p = 0.046). The overall sensitivity of noncathartic CTC for adenomatous polyps ≥ 6 mm was 76% (28/37; 95% CI, 59-88%), which is similar to the sensitivity of the iodinated regimens with most patients (sensitivity: 231 patients, 74% [14/19; 95% CI, 49-91%]; 229 patients, 80% [12/15; 95% CI, 52-96%]). The negative predictive value was 98% (481/490), and the lone cancer was detected (0.2%, 1/556). EC was thought to improve conspicuity of 10 of 21 visible polyps ≥ 10 mm. In this prospective study of asymptomatic subjects, the per-patient sensitivity of noncathartic CTC for detecting adenomas ≥ 6 mm was approximately 76%. Inclusion of oral iodine contrast material improves examination specificity and the percentage of labeled stool. EC may improve polyp conspicuity.

  3. Strategies for Improved Interpretation of Computer-Aided Detections for CT Colonography Utilizing Distributed Human Intelligence

    PubMed Central

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

    2012-01-01

    Computer-aided detection (CAD) systems have been shown to improve the diagnostic performance of CT colonography (CTC) in the detection of premalignant colorectal polyps. Despite the improvement, the overall system is not optimal. CAD annotations on true lesions are incorrectly dismissed, and false positives are misinterpreted as true polyps. Here, we conduct an observer performance study utilizing distributed human intelligence in the form of anonymous knowledge workers (KWs) to investigate human performance in classifying polyp candidates under different presentation strategies. We evaluated 600 polyp candidates from 50 patients, each case having at least one polyp • 6 mm, from a large database of CTC studies. Each polyp candidate was labeled independently as a true or false polyp by 20 KWs and an expert radiologist. We asked each labeler to determine whether the candidate was a true polyp after looking at a single 3D-rendered image of the candidate and after watching a video fly-around of the candidate. We found that distributed human intelligence improved significantly when presented with the additional information in the video fly-around. We noted that performance degraded with increasing interpretation time and increasing difficulty, but distributed human intelligence performed better than our CAD classifier for “easy” and “moderate” polyp candidates. Further, we observed numerous parallels between the expert radiologist and the KWs. Both showed similar improvement in classification moving from single-image to video interpretation. Additionally, difficulty estimates obtained from the KWs using an expectation maximization algorithm correlated well with the difficulty rating assigned by the expert radiologist. Our results suggest that distributed human intelligence is a powerful tool that will aid in the development of CAD for CTC. PMID:22705287

  4. Colorectal cancer screening: The role of CT colonography

    PubMed Central

    Laghi, Andrea; Iafrate, Franco; Rengo, Marco; Hassan, Cesare

    2010-01-01

    Computed tomography colonography (CTC) in colorectal cancer (CRC) screening has two roles: one present and the other potential. The present role is, without any further discussion, the integration into established screening programs as a replacement for barium enema in the case of incomplete colonoscopy. The potential role is the use of CTC as a first-line screening method together with Fecal Occult Blood Test, sigmoidoscopy and colonoscopy. However, despite the fact that CTC has been officially endorsed for CRC screening of average-risk individuals by different scientific societies including the American Cancer Society, the American College of Radiology, and the US Multisociety Task Force on Colorectal Cancer, other entities, such as the US Preventive Services Task Force, have considered the evidence insufficient to justify its use as a mass screening method. Medicare has also recently denied reimbursement for CTC as a screening test. Nevertheless, multiple advantages exist for using CTC as a CRC screening test: high accuracy, full evaluation of the colon in virtually all patients, non-invasiveness, safety, patient comfort, detection of extracolonic findings and cost-effectiveness. The main potential drawback of a CTC screening is the exposure to ionizing radiation. However, this is not a major issue, since low-dose protocols are now routinely implemented, delivering a dose comparable or slightly superior to the annual radiation exposure of any individual. Indirect evidence exists that such a radiation exposure does not induce additional cancers. PMID:20731011

  5. Computer-aided diagnosis in CT colonography: detection of polyps based on geometric and texture features

    NASA Astrophysics Data System (ADS)

    Yoshida, Hiroyuki; Naeppi, Janne J.; Frimmel, Hans; Dachman, Abraham H.

    2002-05-01

    A computer-aided diagnosis scheme for the detection of colonic polyps in CT colonography has been developed, and its performance has been assessed based on clinical cases with colonoscopy-confirmed polyps. In the scheme, the colon was automatically segmented by use of knowledge-guided segmentation from 3-dimensional isotropic volumes reconstructed from axial CT slices in CT colonography. Polyp candidates are detected by first computing of 3-dimensional geometric features that characterize polyps, and then segmenting of connected components corresponding to suspicious regions by hysteresis thresholding and fuzzy clustering based on these geometric features. False-positive detections are reduced by computation of 3-dimensional texture features characterizing the internal structures of the polyp candidates, followed by application of discriminant analysis to the feature space generated by the geometric and texture features. We applied our scheme to 43 CT colonographic cases with cleansed colon, including 12 polyps larger than 5 mm. In a by-dataset analysis, the CAD scheme yielded a sensitivity of 95% with 1.2 false positives per data set. The false negative was one of the two polyps in a single patient. Consequently, in by-patient analysis, our method yielded 100% sensitivity with 2.0 false positives per patient. The results indicate that our CAD scheme has the potential to detect clinically important polyp cases with a high sensitivity and a relatively low false-positive rate.

  6. Bowel preparation for CT colonography: blinded comparison of magnesium citrate and sodium phosphate for catharsis.

    PubMed

    Borden, Zachary S; Pickhardt, Perry J; Kim, David H; Lubner, Meghan G; Agriantonis, Demetrios J; Hinshaw, J Louis

    2010-01-01

    To compare colonic cleansing and fluid retention of double-dose magnesium citrate with those of single-dose sodium phosphate in patients undergoing computed tomographic (CT) colonography. This retrospective HIPAA-compliant clinical study had institutional review board approval; informed consent was waived. The study included 118 consecutive patients given single-dose sodium phosphate for bowel catharsis and 115 consecutive patients at risk for phosphate nephropathy, who were instead given double-dose magnesium citrate. The bowel preparation regimen was otherwise identical. Four-point scales were used to assess residual stool and fluid in the six colonic segments, and attenuation of residual fluid was measured. An a priori power analysis was performed, and unpaired t tests with Welch correction were used to compare the two groups on stool and fluid scores and fluid attenuation. Both cathartic regimens offered excellent colon cleansing, with no significant difference for residual stool in any of the six segments. Stool scores of 1 or 2 (ie, no residual stool or residual stool <5 mm) were recorded in 88.6% (627 of 708) of colonic segments in the sodium phosphate group and in 88.1% (608 of 690) in the magnesium citrate group. No clinically important differences were seen in residual fluid scores in any of the six segments, with the only significant difference seen in the sigmoid colon (2.17 for sodium phosphate vs 2.44 for magnesium citrate; P< 0.01). Fluid attenuation was significantly different between magnesium citrate and sodium phosphate groups (790 HU +/- 216 vs 978 HU +/- 160; P <.001). Both sodium phosphate and magnesium citrate provided excellent colon cleansing for CT colonography. Residual stool and fluid were similar in both groups, and fluid attenuation values were closer to optimal in the magnesium citrate group. Since bowel preparation provided by both cathartics was comparable, magnesium citrate should be considered for CT colonography, particularly in

  7. Suspected extracolonic neoplasms detected on CT colonography: literature review and possible outcomes.

    PubMed

    Wernli, Karen J; Rutter, Carolyn M; Dachman, Abraham H; Zafar, Hanna M

    2013-06-01

    This study summarizes the literature on the detection of cancer among indeterminate extracolonic findings on computed tomographic (CT) colonography in five targeted organs. We searched PubMed for English-language literature published between January 1, 1994, and December 31, 2010. We describe extracolonic findings in the kidney, lung, liver, pancreas, and ovary suspect for malignancy as they are associated with high mortality. For each organ, we calculated the median prevalence, positive predictive value (PPV), and false positive rate of malignancy and a pooled false-positive rate across studies. Of 91 publications initially identified, 24 were eligible for review. Indeterminate renal masses on CT colonography had 20.5% median PPV and low pooled false positive rate of 1.3% (95% confidence interval 0.6-2.0). In contrast, indeterminate masses of the lung, liver, pancreas, and ovary had low PPV (median values ranged from 0% to 3.8%). Indeterminate masses of the ovary resulted in the highest pooled false-positive rate of 2.2%. Results were similar in studies of both screening and nonscreening populations. We estimated the probability of false positive results through the detection of significant extracolonic findings as 46 per 1000 for men and 68 per 1000 for women. Indeterminate renal masses newly detected on CT colonography have an estimated one in five chance of malignancy and therefore warrant further follow-up to provide a definitive diagnosis. Conversely, indeterminate masses of the lung, liver, pancreas, and ovary are associated with high false positive rates and merit more conservative clinical follow-up. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  8. Screening for colorectal neoplasia with CT colonography: initial experience from the 1st year of coverage by third-party payers.

    PubMed

    Pickhardt, Perry J; Taylor, Andrew J; Kim, David H; Reichelderfer, Mark; Gopal, Deepak V; Pfau, Patrick R

    2006-11-01

    To evaluate our experience in the 1st year of computed tomographic (CT) colonography screening since the initiation of local third-party payer coverage. This HIPAA-compliant study was approved by the institutional review board, and informed consent was waived. Over a 1-year period that ended on April 27, 2005, 1110 consecutive adults (585 women, 525 men; mean age, 58.1 years) underwent primary CT colonography screening. More than 99% were covered by managed care agreements. CT colonographic interpretation was performed with primary three-dimensional polyp detection, and the final results were issued within 2 hours. Patients with large (> or =10-mm) polyps were referred for same-day optical colonoscopy, and patients with medium-sized (6-9-mm) lesions had the option of immediate optical colonoscopy or short-term CT colonography surveillance. Large colorectal polyps were identified at CT colonography in 43 (3.9%) of 1110 patients. Medium-sized lesions were identified in 77 (6.9%) patients, 31 (40%) of whom chose optical colonoscopy and 46 (60%) of whom chose CT colonography surveillance. Concordant lesions were identified in 65 of 71 patients who underwent subsequent optical colonoscopy (positive predictive value, 91.5%). Sixty-one (86%) of 71 optical colonoscopic procedures were performed on the same day as CT colonography, thereby avoiding the need for repeat bowel preparation. The actual endoscopic referral rate for positive findings at CT colonography was 6.4% (71 of 1110 patients). The demand for CT colonography screening from primary care physicians and their patients increased throughout the study period. As a primary colorectal screening tool, CT colonography covered by third-party payers has an acceptably low endoscopic referral rate and a high concordance of positive findings at optical colonoscopy.

  9. New 3D Bolton standards: coregistration of biplane x rays and 3D CT

    NASA Astrophysics Data System (ADS)

    Dean, David; Subramanyan, Krishna; Kim, Eun-Kyung

    1997-04-01

    The Bolton Standards 'normative' cohort (16 males, 16 females) have been invited back to the Bolton-Brush Growth Study Center for new biorthogonal plain film head x-rays and 3D (three dimensional) head CT-scans. A set of 29 3D landmarks were identified on both their biplane head film and 3D CT images. The current 3D CT image is then superimposed onto the landmarks collected from the current biplane head films. Three post-doctoral fellows have collected 37 3D landmarks from the Bolton Standards' 40 - 70 year old biplane head films. These films were captured annually during their growing period (ages 3 - 18). Using 29 of these landmarks the current 3D CT image is next warped (via thin plate spline) to landmarks taken from each participant's 18th year biplane head films, a process that is successively reiterated back to age 3. This process is demonstrated here for one of the Bolton Standards. The outer skull surfaces will be extracted from each warped 3D CT image and an average will be generated for each age/sex group. The resulting longitudinal series of average 'normative' boney skull surface images may be useful for craniofacial patient: diagnosis, treatment planning, stereotactic procedures, and outcomes assessment.

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

    PubMed

    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.

  11. Business plan to establish a CT colonography service.

    PubMed

    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.

  12. Tracking eye gaze during interpretation of endoluminal three-dimensional CT colonography: visual perception of experienced and inexperienced readers.

    PubMed

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

    2014-12-01

    To identify and compare key stages of the visual process in experienced and inexperienced readers and to examine how these processes are used to search a moving three-dimensional ( 3D three-dimensional ) image and their relationship to false-negative errors. Institutional review board research ethics approval was granted to use anonymized computed tomographic (CT) colonographic data from previous studies and to obtain eye-tracking data from volunteers. Sixty-five radiologists (27 experienced, 38 inexperienced) interpreted 23 endoluminal 3D three-dimensional CT colonographic videos. Eye movements were recorded by using eye tracking with a desk-mounted tracker. Readers indicated when they saw a polyp by clicking a computer mouse. Polyp location and boundary on each video frame were quantified and gaze data were related to the polyp boundary for each individual reader and case. Predefined metrics were quantified and used to describe and compare visual search patterns between experienced and inexperienced readers by using multilevel modeling. Time to first pursuit was significantly shorter in experienced readers (hazard ratio, 1.22 [95% confidence interval: 1.04, 1.44]; P = .017) but other metrics were not significantly different. Regardless of expertise, metrics such as assessment, identification period, and pursuit times were extended in videos where polyps were visible on screen for longer periods of time. In 97% (760 of 787) of observations, readers correctly pursued polyps. Experienced readers had shorter time to first eye pursuit, but many other characteristics of eye tracking were similar between experienced and inexperienced readers. Readers pursued polyps in 97% of observations, which indicated that errors during interpretation of 3D three-dimensional CT colonography in this study occurred in either the discovery or the recognition phase, but rarely in the scanning phase of radiologic image inspection. © RSNA, 2014.

  13. Fast and robust method to compute colon centerline in CT colonography

    NASA Astrophysics Data System (ADS)

    Frimmel, Hans; Naeppi, Janne J.; Yoshida, Hiroyuki

    2003-05-01

    We developed a method for generating the centerline of a colon in CT Colonography that is computationally fast, and robust to collapsed regions. Patients underwent CT Colonography after standard pre-colonoscopy cleansing. The colonic lumen was segmented using an existing anatomy-based approach, and a distance map of the colonic lumen was computed using a distance transform. The centerline was computed as follows: Local maxima representative for the centerline were sparsely extracted from the distance map. Iteratively, each pair of maxima satisfying a set of connection criteria were connected, creating a graph-like structure containing a main centerline with additional branches. Branches were later removed and the resulting centerline was stored. Centerlines of the colon were computed, and also manually and independently drawn by two radiologists, for 33 CT Colonographic data sets. The data sets were chosen to give a wide spectrum of colons, ranging from cases with good segmentation and extension to cases with collapsed regions and numerous extra-colonic components such as small bowel. On average, 94% of the human-generated centerlines were correctly identified by the computer-generated centerlines. The average displacement between the human- and computer-generated centerlines was 4.0 mm. Average centerline computation time was less than 4 seconds.

  14. Computer-aided detection of polyps in CT colonography based on geometric features

    NASA Astrophysics Data System (ADS)

    Yoshida, Hiroyuki; Masutani, Yoshitaka; MacEneaney, Peter; Dachman, Abraham H.

    2001-05-01

    CT colonography is a promising technique with a long-term goal to provide mass screening for colorectal carcinoma. Colorectal screening by CT colonography requires that the examination be cost-effective. The correct interpretation time is excessive for a screening test. Therefore, a computerized detection method capable of indicating regions of suspicion is attractive as a diagnostic aid for radiologists. We have developed a new CAD scheme for automated detection of polyps based on CT colonographic data sets. Our method characterizes polyps by geometric features of volumetric data including the volumetric shape index and curvedness. Polyps were detected by fuzzy clustering in a feature space generated by the feature values and spatial coordinates, followed by a rule-based test in the feature space. In an analysis of 41 patients, 9 of whom had at least one biopsy-proved polyp, our CAD scheme detected 100% of polyps with 2.5 false positives per patient. Our preliminary result indicates that the CAD scheme is potentially useful for highlighting areas of suspicion in the colon and, therefore, facilitates widespread screening by reducing the reading time substantially.

  15. Patient willingness for repeat screening and preference for CT colonography and optical colonoscopy in ACRIN 6664: the National CT Colonography trial.

    PubMed

    Gareen, Ilana F; Siewert, Bettina; Vanness, David J; Herman, Benjamin; Johnson, C D; Gatsonis, Constantine

    2015-01-01

    Current American Cancer Society recommendations for colon cancer screening include optical colonoscopy every 10 years or computed tomography colonography (CTC) every 5 years. Bowel preparation (BP) is currently required for both screening modalities. To compare ACRIN 6664: the National CT Colonography Trial (NCTCT) participant experiences with CTC and optical colonoscopy (OC), procedure preference, and willingness to return for each procedure. Participants from fifteen NCTCT sites, who underwent CTC followed by OC under sedation, were invited to complete questionnaires 2 weeks postexam, asking about procedure preference, physical discomfort, and embarrassment experienced and whether that discomfort and embarrassment was better or worse than expected during BP, CTC, and OC, as well as willingness to return for repeat CTC and OC at different time intervals. A total of 2,310 of 2,600 patients (89%) returned their questionnaires. Of patients reporting a preference, 1,058 (46.6%) preferred CTC, 569 (25.0%) preferred OC, and 626 (27.6%) reported no preference. Participant-reported discomfort worse than expected differed significantly between CTC (32.9%) and OC (5.0%) (P<0.001). About 79.3% were willing to be screened again with CTC in 5 years, and 96.6% with OC in 10 years. Discomfort and embarrassment worse than expected with OC were associated with increased intention to adhere with CTC in the future. Conversely, embarrassment experienced during CTC and discomfort worse than expected on CTC were associated with increased intention to adhere with OC in the future. While a larger proportion of participants indicated that they preferred CTC to OC, willingness to undergo repeat CTC compared to OC was limited by unanticipated exam discomfort and embarrassment and CTC's shorter screening interval.

  16. Patient willingness for repeat screening and preference for CT colonography and optical colonoscopy in ACRIN 6664: the National CT Colonography trial

    PubMed Central

    Gareen, Ilana F; Siewert, Bettina; Vanness, David J; Herman, Benjamin; Johnson, CD; Gatsonis, Constantine

    2015-01-01

    Background Current American Cancer Society recommendations for colon cancer screening include optical colonoscopy every 10 years or computed tomography colonography (CTC) every 5 years. Bowel preparation (BP) is currently required for both screening modalities. Purpose To compare ACRIN 6664: the National CT Colonography Trial (NCTCT) participant experiences with CTC and optical colonoscopy (OC), procedure preference, and willingness to return for each procedure. Materials and methods Participants from fifteen NCTCT sites, who underwent CTC followed by OC under sedation, were invited to complete questionnaires 2 weeks postexam, asking about procedure preference, physical discomfort, and embarrassment experienced and whether that discomfort and embarrassment was better or worse than expected during BP, CTC, and OC, as well as willingness to return for repeat CTC and OC at different time intervals. Results A total of 2,310 of 2,600 patients (89%) returned their questionnaires. Of patients reporting a preference, 1,058 (46.6%) preferred CTC, 569 (25.0%) preferred OC, and 626 (27.6%) reported no preference. Participant-reported discomfort worse than expected differed significantly between CTC (32.9%) and OC (5.0%) (P<0.001). About 79.3% were willing to be screened again with CTC in 5 years, and 96.6% with OC in 10 years. Discomfort and embarrassment worse than expected with OC were associated with increased intention to adhere with CTC in the future. Conversely, embarrassment experienced during CTC and discomfort worse than expected on CTC were associated with increased intention to adhere with OC in the future. Conclusion While a larger proportion of participants indicated that they preferred CTC to OC, willingness to undergo repeat CTC compared to OC was limited by unanticipated exam discomfort and embarrassment and CTC’s shorter screening interval. PMID:26229451

  17. Volume rendering with color coding of tagged stool during endoluminal fly-through CT colonography: effect on reading efficiency.

    PubMed

    Park, Seong Ho; Lee, Seung Soo; Kim, Jin Kook; Kim, Min-Ju; Kim, Hye Jin; Kim, So Yeon; Kim, Min-Yeong; Kim, Ah Young; Ha, Hyun Kwon

    2008-09-01

    Institutional review board approval and informed consent were obtained. This study was conducted to evaluate a newly developed technique for discriminative color coding of tagged stool during three-dimensional (3D) endoluminal fly-through computed tomographic (CT) colonography and to determine its effect on reading efficiency. Thirty patients, including three dropouts, were prepared with moderate cathartic preparation (20 mg bisacodyl, three doses of 200 mL of 5% wt/vol barium sulfate). Images were reviewed by two independent readers with and without color coding. Reader preference, interpretation time, and diagnostic performance were evaluated. Both reviewers preferred color coding. With color coding, interpretation time was shortened by 3 minutes (reader 1, P = .002) and 2.5 minutes (reader 2, P = .009); sensitivity for 6-mm-diameter or larger lesions remained constant at 96% (24 of 25; 95% confidence interval: 78.9%, <100%; P = >.99). This technique facilitates primary 3D interpretation of images obtained with moderate cathartic preparation. RSNA, 2008

  18. Informatics in radiology: dual-energy electronic cleansing for fecal-tagging CT colonography.

    PubMed

    Cai, Wenli; Kim, Se Hyung; Lee, June-Goo; Yoshida, Hiroyuki

    2013-05-01

    Electronic cleansing (EC) is an emerging technique for the removal of tagged fecal materials at fecal-tagging computed tomographic (CT) colonography. However, existing EC methods may generate various types of artifacts that severely impair the quality of the cleansed CT colonographic images. Dual-energy fecal-tagging CT colonography is regarded as a next-generation imaging modality. EC that makes use of dual-energy fecal-tagging CT colonographic images promises to be effective in reducing cleansing artifacts by means of applying the material decomposition capability of dual-energy CT. The dual-energy index (DEI), which is calculated from the relative change in the attenuation values of a material at two different photon energies, is a reliable and effective indicator for differentiating tagged fecal materials from various types of tissues on fecal-tagging CT colonographic images. A DEI-based dual-energy EC scheme uses the DEI to help differentiate the colonic lumen-including the luminal air, tagged fecal materials, and air-tagging mixture-from the colonic soft-tissue structures, and then segments the entire colonic lumen for cleansing of the tagged fecal materials. As a result, dual-energy EC can help identify partial-volume effects in the air-tagging mixture and inhomogeneous tagging in residual fecal materials, the major causes of EC artifacts. This technique has the potential to significantly improve the quality of EC and promises to provide images of a cleansed colon that are free of the artifacts commonly observed with conventional single-energy EC methods.

  19. Informatics in Radiology: Dual-Energy Electronic Cleansing for Fecal-Tagging CT Colonography

    PubMed Central

    Kim, Se Hyung; Lee, June-Goo; Yoshida, Hiroyuki

    2013-01-01

    Electronic cleansing (EC) is an emerging technique for the removal of tagged fecal materials at fecal-tagging computed tomographic (CT) colonography. However, existing EC methods may generate various types of artifacts that severely impair the quality of the cleansed CT colonographic images. Dual-energy fecal-tagging CT colonography is regarded as a next-generation imaging modality. EC that makes use of dual-energy fecal-tagging CT colonographic images promises to be effective in reducing cleansing artifacts by means of applying the material decomposition capability of dual-energy CT. The dual-energy index (DEI), which is calculated from the relative change in the attenuation values of a material at two different photon energies, is a reliable and effective indicator for differentiating tagged fecal materials from various types of tissues on fecal-tagging CT colonographic images. A DEI-based dual-energy EC scheme uses the DEI to help differentiate the colonic lumen—including the luminal air, tagged fecal materials, and air-tagging mixture—from the colonic soft-tissue structures, and then segments the entire colonic lumen for cleansing of the tagged fecal materials. As a result, dual-energy EC can help identify partial-volume effects in the air-tagging mixture and inhomogeneous tagging in residual fecal materials, the major causes of EC artifacts. This technique has the potential to significantly improve the quality of EC and promises to provide images of a cleansed colon that are free of the artifacts commonly observed with conventional single-energy EC methods. © RSNA, 2013 PMID:23479680

  20. Objective volumetric comparison of room air versus carbon dioxide for colonic distention at screening CT colonography.

    PubMed

    Patrick, James L; Bakke, Joshua R; Bannas, Peter; Kim, David H; Lubner, Meghan G; Pickhardt, Perry J

    2015-02-01

    To objectively compare colonic distention at CT colonography (CTC) achieved with manual room air vs. automated low-pressure carbon dioxide (CO2) using a novel automated volumetric quality assessment tool. Volumetric analysis was retrospectively performed on CTC studies in 300 asymptomatic adults using an automated quality assessment tool (V3D Colon [beta version], Viatronix). Colonic distention was achieved with room air self-administered to tolerance via hand-held pump (mean number of pumps, 39 ± 32) in 150 individuals (mean age, 59 years; 98 men, 51 women) and via continuous low-pressure automated infusion of CO2 in 150 individuals (mean age, 57 years; 89 men, 61 women). CTC studies in supine and prone position were assessed to determine total colonic volume (luminal gas and fluid). The colonic length along the automated centerline was also recorded to enable calculation of length-adjusted colonic volumes. The mean total colonic volume (±SD) for individuals receiving room air and CO2 distention was 1809 ± 514 and 2223 ± 686 mL, respectively (p < 0.01). The prone position was better distended in 78.7% (118/150) of cases using room air; whereas, the supine was better in 66.0% (99/150) of CO2 cases (p < 0.01). Using a volume threshold of 2000 mL, 49 (32.7%) of room air cases and 92 (61.3%) of CO2 cases were above this cut-off. The mean length-adjusted colonic volume (mL/cm) for the room air and CO2 techniques was 9.9 ± 2.4 and 11.6 ± 2.6 mL/cm (p < 0.01). Using automated volumetry allowed quantitative analyses of colonic volumes and objectively confirmed that continuous low-pressure CO2 provides greater overall colonic distention than the manual room air technique at CTC. The supine position demonstrated better distention with CO2, whereas the prone position was better distended with the room air technique.

  1. Ct3d: tracking microglia motility in 3D using a novel cosegmentation approach.

    PubMed

    Xiao, Hang; Li, Ying; Du, Jiulin; Mosig, Axel

    2011-02-15

    Cell tracking is an important method to quantitatively analyze time-lapse microscopy data. While numerous methods and tools exist for tracking cells in 2D time-lapse images, only few and very application-specific tracking tools are available for 3D time-lapse images, which is of high relevance in immunoimaging, in particular for studying the motility of microglia in vivo. We introduce a novel algorithm for tracking cells in 3D time-lapse microscopy data, based on computing cosegmentations between component trees representing individual time frames using the so-called tree-assignments. For the first time, our method allows to track microglia in three dimensional confocal time-lapse microscopy images. We also evaluate our method on synthetically generated data, demonstrating that our algorithm is robust even in the presence of different types of inhomogeneous background noise. Our algorithm is implemented in the ct3d package, which is available under http://www.picb.ac.cn/patterns/Software/ct3d; supplementary videos are available from http://www.picb.ac.cn/patterns/Supplements/ct3d.

  2. Development of a 3D CT scanner using cone beam

    NASA Astrophysics Data System (ADS)

    Endo, Masahiro; Kamagata, Nozomu; Sato, Kazumasa; Hattori, Yuichi; Kobayashi, Shigeo; Mizuno, Shinichi; Jimbo, Masao; Kusakabe, Masahiro

    1995-05-01

    In order to acquire 3D data of high contrast objects such as bone, lung and vessels enhanced by contrast media for use in 3D image processing, we have developed a 3D CT-scanner using cone beam x ray. The 3D CT-scanner consists of a gantry and a patient couch. The gantry consists of an x-ray tube designed for cone beam CT and a large area two-dimensional detector mounted on a single frame and rotated around an object in 12 seconds. The large area detector consists of a fluorescent plate and a charge coupled device video camera. The size of detection area was 600 mm X 450 mm capable of covering the total chest. While an x-ray tube was rotated around an object, pulsed x ray was exposed 30 times a second and 360 projected images were collected in a 12 second scan. A 256 X 256 X 256 matrix image (1.25 mm X 1.25 mm X 1.25 mm voxel) was reconstructed by a high-speed reconstruction engine. Reconstruction time was approximately 6 minutes. Cylindrical water phantoms, anesthetized rabbits with or without contrast media, and a Japanese macaque were scanned with the 3D CT-scanner. The results seem promising because they show high spatial resolution in three directions, though there existed several point to be improved. Possible improvements are discussed.

  3. Primary Gallbladder Lymphoma in a Male Patient with No Risk Factors Detected Incidentally by CT Colonography

    PubMed Central

    Karia, Monil; Mitsopoulos, Grigorios; Patel, Ketan; Rafique, Akkib; Sheth, Hemant

    2015-01-01

    Primary gallbladder lymphoma, although rare, usually presents in females with symptoms mimicking cholecystitis. We present a rare case of primary gallbladder in an 81-year-old male with no risk factors whose only symptom was weight loss. Routine blood tests including liver function tests were unremarkable. A CT colonography was carried out to exclude colonic malignancy. Unilateral gallbladder wall thickening and lymphadenopathy were incidentally detected and confirmed by ultrasound and a decision for the patient to undergo laparoscopic cholecystectomy and intraoperative cholangiogram was made. Histology confirmed extranodal marginal zone lymphoma with follow-up staging and biopsy of the bone marrow not demonstrating spread. Cholecystectomy was therefore deemed curative and no adjuvant therapy was necessary. Thickening of the gallbladder wall on any imaging with or without symptoms should not be ignored or assumed to be cholecystitis, even in males with no risk factors. In these patients urgent cholecystectomy with intraoperative cholangiogram is indicated with histology and haematology follow-up. PMID:26587306

  4. Evaluation of two minimal-preparation regimes for CT colonography: optimising image quality and patient acceptability.

    PubMed

    Pollentine, A; Mortimer, A; McCoubrie, P; Archer, L

    2012-08-01

    To compare a 2 day bowel preparation regime of barium, iodine and a mild stimulant laxative with a 1 day iodine-only regime for CT colonography (CTC). 100 consecutive patients underwent CTC. The first 50 patients (Regime 1) ingested 1 bisacodyl tablet twice a day 3 days before CTC and 1 dose each of 50 ml of barium and 20 ml of iodinated contrast per day starting 2 days before CTC. The second 50 patients (Regime 2) ingested 3 doses of iodinated contrast over 24 h prior to CTC. Volumes of residual stool and fluid, and the effectiveness of stool and fluid tagging, were graded according to methods established by Taylor et al (Taylor S, Slaker A, Burling D, Tam E, Greenhalgh R, Gartner L, et al. CT colonography: optimisation, diagnostic performance and patient acceptability of reduced-laxative regimens using barium-based faecal tagging. Eur Radiol 2008; 18: 32-42). A 3 day low-residue diet was taken by both cohorts. Questionnaires rating the side-effects and burden of the bowel preparation were compared to a control cohort of patients undergoing barium enema. The proportion of colons producing none/scattered stool (score 1) was 90.3% with Regime 1 and 65.0% with Regime 2 (p<0.005). Any residual stool was significantly better tagged with Regime 1 (score 5), with 91.7% of Regime 1 exhibiting optimum tagging vs 71.3% of Regime 2 (p<0.05). No significant differences in side-effects between the bowel preparation regimes for CTC were elicited. Bowel preparation for barium enema was tolerated significantly worse than both of the CTC bowel preparation regimes. Regime 1, containing a 3 day preparation of a mild laxative, barium and iodine, produced a significantly better prepared colon, with no difference in patient acceptability.

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

    PubMed

    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

  6. Automated 3D vascular segmentation in CT hepatic venography

    NASA Astrophysics Data System (ADS)

    Fetita, Catalin; Lucidarme, Olivier; Preteux, Francoise

    2005-08-01

    In the framework of preoperative evaluation of the hepatic venous anatomy in living-donor liver transplantation or oncologic rejections, this paper proposes an automated approach for the 3D segmentation of the liver vascular structure from 3D CT hepatic venography data. The developed segmentation approach takes into account the specificities of anatomical structures in terms of spatial location, connectivity and morphometric properties. It implements basic and advanced morphological operators (closing, geodesic dilation, gray-level reconstruction, sup-constrained connection cost) in mono- and multi-resolution filtering schemes in order to achieve an automated 3D reconstruction of the opacified hepatic vessels. A thorough investigation of the venous anatomy including morphometric parameter estimation is then possible via computer-vision 3D rendering, interaction and navigation capabilities.

  7. Validation of 3D ultrasound: CT registration of prostate images

    NASA Astrophysics Data System (ADS)

    Firle, Evelyn A.; Wesarg, Stefan; Karangelis, Grigoris; Dold, Christian

    2003-05-01

    All over the world 20% of men are expected to develop prostate cancer sometime in his life. In addition to surgery - being the traditional treatment for cancer - the radiation treatment is getting more popular. The most interesting radiation treatment regarding prostate cancer is Brachytherapy radiation procedure. For the safe delivery of that therapy imaging is critically important. In several cases where a CT device is available a combination of the information provided by CT and 3D Ultrasound (U/S) images offers advantages in recognizing the borders of the lesion and delineating the region of treatment. For these applications the CT and U/S scans should be registered and fused in a multi-modal dataset. Purpose of the present development is a registration tool (registration, fusion and validation) for available CT volumes with 3D U/S images of the same anatomical region, i.e. the prostate. The combination of these two imaging modalities interlinks the advantages of the high-resolution CT imaging and low cost real-time U/S imaging and offers a multi-modality imaging environment for further target and anatomy delineation. This tool has been integrated into the visualization software "InViVo" which has been developed over several years in Fraunhofer IGD in Darmstadt.

  8. An automatic approach for 3D registration of CT scans

    NASA Astrophysics Data System (ADS)

    Hu, Yang; Saber, Eli; Dianat, Sohail; Vantaram, Sreenath Rao; Abhyankar, Vishwas

    2012-03-01

    CT (Computed tomography) is a widely employed imaging modality in the medical field. Normally, a volume of CT scans is prescribed by a doctor when a specific region of the body (typically neck to groin) is suspected of being abnormal. The doctors are required to make professional diagnoses based upon the obtained datasets. In this paper, we propose an automatic registration algorithm that helps healthcare personnel to automatically align corresponding scans from 'Study' to 'Atlas'. The proposed algorithm is capable of aligning both 'Atlas' and 'Study' into the same resolution through 3D interpolation. After retrieving the scanned slice volume in the 'Study' and the corresponding volume in the original 'Atlas' dataset, a 3D cross correlation method is used to identify and register various body parts.

  9. [Volumetric CT scanning: 2D and 3D reconstruction].

    PubMed

    Ferretti, G-R; Jankowski, A

    2010-12-01

    This review aims to present the 2D and 3D reconstructions derived from high-resolution volume CT acquisitions and to illustrate their thoracic applications, as well as showing the interest and limitations of these techniques. We present new applications for computer-assisted detection (CAD) and tools for quantification of pulmonary lesions. Copyright © 2010 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  10. Electronic cleansing for CT colonography using spectral-driven iterative reconstruction

    NASA Astrophysics Data System (ADS)

    Nasirudin, Radin A.; Näppi, Janne J.; Hironaka, Toru; Tachibana, Rie; Yoshida, Hiroyuki

    2017-03-01

    Dual-energy computed tomography is used increasingly in CT colonography (CTC). The combination of computer-aided detection (CADe) and dual-energy CTC (DE-CTC) has high clinical value, because it can detect clinically significant colonic lesions automatically at higher accuracy than does conventional single-energy CTC. While CADe has demonstrated its ability to detect small polyps, its performance is highly dependent on several factors, including the quality of CTC images and electronic cleansing (EC) of the images. The presence of artifacts such as beam hardening and image noise in ultra-low-dose CTC can produce incorrectly cleansed colon images that severely degrade the detection performance of CTC for small polyps. Also, CADe methods are very dependent on the quality of input images and the information about different tissues in the colon. In this work, we developed a novel method to calculate EC images using spectral information from DE-CTC data. First, the ultra-low dose dual-energy projection data obtained from a CT scanner are decomposed into two materials, soft tissue and the orally administered fecal-tagging contrast agent, to detect the location and intensity of the contrast agent. Next, the images are iteratively reconstructed while gradually removing the presence of tagged materials from the images. Our preliminary qualitative results show that the method can cleanse the contrast agent and tagged materials correctly from DE-CTC images without affecting the appearance of surrounding tissue.

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

    PubMed

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

    2017-06-01

    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 <5 mm were also detected. The results were validated qualitatively and quantitatively using both 2D MPR and 3D view. Implementation was done on a high-performance computer with parallel 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].

  12. Participation and yield of colonoscopy versus non-cathartic CT colonography in population-based screening for colorectal cancer: a randomised controlled trial.

    PubMed

    Stoop, Esther M; de Haan, Margriet C; de Wijkerslooth, Thomas R; Bossuyt, Patrick M; van Ballegooijen, Marjolein; Nio, C Yung; van de Vijver, Marc J; Biermann, Katharina; Thomeer, Maarten; van Leerdam, Monique E; Fockens, Paul; Stoker, Jaap; Kuipers, Ernst J; Dekker, Evelien

    2012-01-01

    Screening for colorectal cancer is widely recommended, but the preferred strategy remains unidentified. We aimed to compare participation and diagnostic yield between screening with colonoscopy and with non-cathartic CT colonography. Members of the general population, aged 50-75 years, and living in the regions of Amsterdam or Rotterdam, identified via the registries of the regional municipal administration, were randomly allocated (2:1) to be invited for primary screening for colorectal cancer by colonoscopy or by CT colonography. Randomisation was done per household with a minimisation algorithm based on age, sex, and socioeconomic status. Invitations were sent between June 8, 2009, and Aug 16, 2010. Participants assigned to CT colonography who were found to have one or more large lesions (≥10 mm) were offered colonoscopy; those with 6-9 mm lesions were offered surveillance CT colonography. The primary outcome was the participation rate, defined as number of invitees undergoing the examination relative to the total number of invitees. Diagnostic yield was calculated as number of participants with advanced neoplasia relative to the total number of invitees. Invitees and screening centre employees were not masked to allocation. This trial is registered in the Dutch trial register, number NTR1829. 1276 (22%) of 5924 colonoscopy invitees participated, compared with 982 (34%) of 2920 CT colonography invitees (relative risk [RR] 1·56, 95% CI 1·46-1·68; p<0·0001). Of the participants in the colonoscopy group, 111 (9%) had advanced neoplasia of whom seven (<1%) had a carcinoma. Of CT colonography participants, 84 (9%) were offered colonoscopy, of whom 60 (6%) had advanced neoplasia of whom five (<1%) had a carcinoma; 82 (8%) were offered surveillance. The diagnostic yield for all advanced neoplasia was 8·7 per 100 participants for colonoscopy versus 6·1 per 100 for CT colonography (RR 1·46, 95% CI 1·06-2·03; p=0·02) and 1·9 per 100 invitees for colonoscopy

  13. Texture-based CAD improves diagnosis for low-dose CT colonography

    NASA Astrophysics Data System (ADS)

    Liang, Zhengrong; Cohen, Harris; Posniak, Erica; Fiore, Eddie; Wang, Zigang; Li, Bin; Andersen, Joseph; Harrington, Donald

    2008-03-01

    Computed tomography (CT)-based virtual colonoscopy or CT colonography (CTC) currently utilizes oral contrast solutions to tag the colonic fluid and possibly residual stool for differentiation from the colon wall and polyps. The enhanced image density of the tagged colonic materials causes a significant partial volume (PV) effect into the colon wall as well as the lumen space (filled with air or CO II). The PV effect on the colon wall can "bury" polyps of size as large as 5mm by increasing their image densities to a noticeable level, resulting in false negatives. It can also create false positives when PV effect goes into the lumen space. We have been modeling the PV effect for mixture-based image segmentation and developing text-based computer-aided detection of polyp (CADpolyp) by utilizing the PV mixture-based image segmentation. This work presents some preliminary results of developing and applying texture-based CADpolyp technique to low-dose CTC studies. A total of 114 studies of asymptomatic patients older than 50, who underwent CTC and then optical colonoscopy (OC) on the same day, were selected from a database, which was accumulated in the past decade and contains various bowel preparations and CT scanning protocols. The participating radiologists found ten polyps of greater than 5 mm from a total of 16 OC proved polyps, i.e., a detection sensitivity of 63%. They scored 23 false positives from the database, i.e., a 20% false positive rate. Approximately 70% of the datasets were marked as imperfect bowel cleansing and/or presence of image artifacts. The impact of imperfect bowel cleansing and image artifacts on VC performance is significant. The texture-based CADpolyp detected all the polyps with an average of 2.68 false positives per patient. This indicates that texture-based CADpolyp can improve the CTC performance in the cases of imperfect cleansed bowels and presence of image artifacts.

  14. Aortic valve and ascending aortic root modeling from 3D and 3D+t CT

    NASA Astrophysics Data System (ADS)

    Grbic, Saša; Ionasec, Razvan I.; Zäuner, Dominik; Zheng, Yefeng; Georgescu, Bogdan; Comaniciu, Dorin

    2010-02-01

    Aortic valve disorders are the most frequent form of valvular heart disorders (VHD) affecting nearly 3% of the global population. A large fraction among them are aortic root diseases, such as aortic root aneurysm, often requiring surgical procedures (valve-sparing) as a treatment. Visual non-invasive assessment techniques could assist during pre-selection of adequate patients, planning procedures and afterward evaluation of the same. However state of the art approaches try to model a rather short part of the aortic root, insufficient to assist the physician during intervention planning. In this paper we propose a novel approach for morphological and functional quantification of both the aortic valve and the ascending aortic root. A novel physiological shape model is introduced, consisting of the aortic valve root, leaflets and the ascending aortic root. The model parameters are hierarchically estimated using robust and fast learning-based methods. Experiments performed on 63 CT sequences (630 Volumes) and 20 single phase CT volumes demonstrated an accuracy of 1.45mm and an performance of 30 seconds (3D+t) for this approach. To the best of our knowledge this is the first time a complete model of the aortic valve (including leaflets) and the ascending aortic root, estimated from CT, has been proposed.

  15. Improved computer-aided detection of small polyps in CT colonography using interpolation for curvature estimationa

    PubMed Central

    Liu, Jiamin; Kabadi, Suraj; Van Uitert, Robert; Petrick, Nicholas; Deriche, Rachid; Summers, Ronald M.

    2011-01-01

    Purpose: Surface curvatures are important geometric features for the computer-aided analysis and detection of polyps in CT colonography (CTC). However, the general kernel approach for curvature computation can yield erroneous results for small polyps and for polyps that lie on haustral folds. Those erroneous curvatures will reduce the performance of polyp detection. This paper presents an analysis of interpolation’s effect on curvature estimation for thin structures and its application on computer-aided detection of small polyps in CTC. Methods: The authors demonstrated that a simple technique, image interpolation, can improve the accuracy of curvature estimation for thin structures and thus significantly improve the sensitivity of small polyp detection in CTC. Results: Our experiments showed that the merits of interpolating included more accurate curvature values for simulated data, and isolation of polyps near folds for clinical data. After testing on a large clinical data set, it was observed that sensitivities with linear, quadratic B-spline and cubic B-spline interpolations significantly improved the sensitivity for small polyp detection. Conclusions: The image interpolation can improve the accuracy of curvature estimation for thin structures and thus improve the computer-aided detection of small polyps in CTC. PMID:21859029

  16. Patient experiences of colonoscopy, barium enema and CT colonography: a qualitative study.

    PubMed

    Von Wagner, C; Knight, K; Halligan, S; Atkin, W; Lilford, R; Morton, D; Wardle, J

    2009-01-01

    Previous studies of patient experience with bowel screening tests, in particular CT colonography (CTC), have superimposed global rating scales and not explored individual experience in detail. To redress this, we performed qualitative interviews in order to characterize patient expectations and experiences in depth. Following ethical permission, 16 patients undergoing CTC, 18 undergoing colonoscopy and 15 undergoing barium enema agreed to a semi-structured interview by a health psychologist. Interviews were recorded, responses transcribed and themes extracted with the aim of assimilating individual experiences to facilitate subsequent development and interpretation of quantitative surveys of overall satisfaction with each diagnostic test. Transcript analysis identified three principal themes: physical sensations, social interactions and information provision. Physical sensations differed for each test but were surprisingly well tolerated overall. Social interactions with staff were perceived as very important in colouring the whole experience, particularly in controlling the feelings of embarrassment, which was critical for all procedures. Information provision was also an important determinant of experience. Verbal feedback was most common during colonoscopy and invariably reassuring. However, patients undergoing CTC received little visual or verbal feedback and were often confused regarding the test outcome. Barium enema had no specific advantage over other tests. Qualitative interviews provided important perspectives on patient experience. Our data demonstrated that models describing the quality of medical encounters are applicable to single diagnostic episodes. Staff interactions and information provision were particularly important. We found advantages specific to both CTC and colonoscopy but none for barium enema. CTC could benefit greatly from improved information provision following examination.

  17. Electronic cleansing for dual-energy CT colonography based on material decomposition and virtual monochromatic imaging

    NASA Astrophysics Data System (ADS)

    Tachibana, Rie; Näppi, Janne J.; Kim, Se Hyung; Yoshida, Hiroyuki

    2015-03-01

    CT colonography (CTC) uses orally administered fecal-tagging agents to enhance retained fluid and feces that would otherwise obscure or imitate polyps on CTC images. To visualize the complete region of colon without residual materials, electronic cleansing (EC) can be used to perform virtual subtraction of the tagged materials from CTC images. However, current EC methods produce subtraction artifacts and they can fail to subtract unclearly tagged feces. We developed a novel multi-material EC (MUMA-EC) method that uses dual-energy CTC (DE-CTC) and machine-learning methods to improve the performance of EC. In our method, material decomposition is performed to calculate wateriodine decomposition images and virtual monochromatic (VIM) images. Using the images, a random forest classifier is used to label the regions of lumen air, soft tissue, fecal tagging, and their partial-volume boundaries. The electronically cleansed images are synthesized from the multi-material and VIM image volumes. For pilot evaluation, we acquired the clinical DE-CTC data of 7 patients. Preliminary results suggest that the proposed MUMA-EC method is effective and that it minimizes the three types of image artifacts that were present in previous EC methods.

  18. Optical Colonoscopy and Virtual Colonoscopy Numbers after Initiation of a CT Colonography Program: Long Term Data

    PubMed Central

    Benson, Mark; Pier, Jeff; Kraft, Sally; Kim, David; Pickhardt, Perry; Weiss, Jennifer; Gopal, Deepak; Reichelderfer, Mark; Pfau, Patrick

    2015-01-01

    Background & Aims The effect of CT colonography (CTC) screening on colonoscopy is unknown. The objective of this study is to determine the effect of a CTC screening program on the number of screening, therapeutic and total colonoscopies performed. Methods We compared the quarterly mean numbers of colonoscopic examinations performed for 50-79 year olds undergoing colorectal cancer screening in 2003, before initiation of a CTC program, to 2011, seven years after the CTC program began at our academic tertiary care facility. Results The CTC program began in 2004 with a peak number of 387 CTC examinations performed in the 3rd quarter of 2005 and 275 examinations in the final quarter of 2011. Screening colonoscopies increased from 555 mean/quarter in 2003 to 1460 in 2011 (P < 0.001). The mean/quarter number of total colonoscopies performed increased from 1104 in 2003 to 2382 in 2011 (P < 0.001). The number of overall colon cancer screening examinations (Colonoscopy + CTC) increased from 555/quarter in 2003 to 1736 in 2011 (P < 0.001). Conclusions Since the initiation of CTC screening at our institution, the overall number of total colorectal cancer screening examinations (CTC + colonoscopy) has greatly increased. The initiation of a CTC screening program did not lead to a reduction in the number of colonoscopic examinations performed. Conversely, a significant increase in the number of screening and total colonoscopies completed was observed. PMID:23256122

  19. Characteristics of false positive findings in CT colonography CAD: a comparison of two fecal tagging regimens

    NASA Astrophysics Data System (ADS)

    Morra, Lia; Delsanto, Silvia; Agliozzo, Silvano; Baggio, Riccardo; Belluccio, Erika; Correale, Loredana; Genova, Dario; Bert, Alberto; Regge, Daniele

    2009-02-01

    The successful application of Computer Aided Detection schemes to CT Colonography depends not only on their performances in terms of sensitivity and specificity, but also on the interaction with the radiologist, and thus ultimately on factors such as the nature of CAD prompts and the reading paradigm. Fecal tagging is emerging as a widely accepted technique for patient preparation, and patient-friendlier schemes are being proposed in an effort to increase compliance to screening programs; the interaction between CAD and FT regimens should likewise be taken into account. In this scenario, an analysis of the characteristics of CAD prompts is of paramount importance in order to guide further research, both from clinical and technical viewpoints. The CAD scheme analyzed in this paper is essentially composed of five steps: electronic cleansing, colon surface extraction, polyp candidate segmentation, pre-filtering of residual tagged stool and classification of the generated candidates in true polyps vs. false alarms. False positives were divided into six categories: untagged and tagged solid stool, haustral folds, extra-colonic candidates, ileocecal valve and cleansing artifacts. A full cathartic preparation was compared with a semi-cathartic regimen with sameday fecal tagging, which is characterized by higher patient acceptance but also higher inhomogeneity. The distribution of false positives at segmentation reflects the quality of preparation, as more inhomogeneous tagging results in a higher number of untagged solid stool and cleansing artifacts.

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

    PubMed

    Mc Laughlin, Patrick; Eustace, Joseph; Mc Sweeney, Sean; Mc Williams, Sebastian; O'Regan, Kevin; O'Connor, Michael; Kelly, Denis; Maher, Michael M

    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. Patients aged over 70 years considered at risk of complication during SPS-MC administration by a physician specialised in care of the elderly were included in this retrospective study. Biochemical parameters pre- and post-CTC and the presence of co-morbidities were recorded. Imaging findings and quality of bowel preparation at CTC were graded by consensus by two radiologists. Of the 72 patients 56% had co-morbidities that caution the use of SPS-MC. No significant changes in serum urea, sodium, potassium or estimated glomerular filtration rate (eGFR) occurred post-CTC (p > 0.10). Serum magnesium increased by 0.11 mmol/L in 14 patients (p = 0.03) without clinical sequelae. Good overall preparation was achieved in 88% of patients, allowing confident identification of signs of colonic neoplasia in 20 patients (27%). A mild increase in serum magnesium but no other significant biochemical disturbance was observed. In our group CTC with SPS-MC was safe and effective; however, we advise an alternate preparation be considered in patients with decreased renal function due to decreased magnesium clearance.

  1. Technical development: CT colonography without cathartic cleansing and with barium as the sole tagging agent

    NASA Astrophysics Data System (ADS)

    Lefere, Philippe; Gryspeerdt, Stefaan; Baekelandt, Marc; Van Holsbeeck, Bartel

    2004-04-01

    The purpose of this study was to perform CT colonography (CTC) without cathartic colon cleansing. Four groups of 3 patients were prepared the day before CTC with a dedicated low residue diet, a hydration control allowing 2 liters of fluid intake and barium as tagging agent. Four different barium regimens were investigated. Groups 1 and 3 ingested barium over 1 day at different concentrations and groups 2 and 4 over 2 days. The barium volume to drink the day before CTC was 750 ml in groups 1 and 2 and 50 ml in groups 3 and 4. The fluid, density measurements of the fecal residue and tagging efficacy were evaluated. All fecal residue with densities >= 150 H.U. was electronically labeled. Per segment a visual labeling score (0, 25, 50, 75, 100%) was performed. The fluid was evaluated according to its proportion to the maximum anteroposterior diameter of the colonic segment where it was detected. No significant differences in densities of tagged residue were detected. The visual labeling scores varied between 90 and 100% in all segments. There were 6 fluid levels: 5 covering < 10% and one covering 50% of the colonic lumen. The lowest density of the fluid was 360 H.U. In this preliminary study we could conclude that CTC without cathartic cleansing and with barium produced efficient labeling of fecal residue. The barium intake could be reduced to one day and to 50 ml.

  2. Deep multi-spectral ensemble learning for electronic cleansing in dual-energy CT colonography

    NASA Astrophysics Data System (ADS)

    Tachibana, Rie; Näppi, Janne J.; Hironaka, Toru; Kim, Se Hyung; Yoshida, Hiroyuki

    2017-03-01

    We developed a novel electronic cleansing (EC) method for dual-energy CT colonography (DE-CTC) based on an ensemble deep convolution neural network (DCNN) and multi-spectral multi-slice image patches. In the method, an ensemble DCNN is used to classify each voxel of a DE-CTC image volume into five classes: luminal air, soft tissue, tagged fecal materials, and partial-volume boundaries between air and tagging and those between soft tissue and tagging. Each DCNN acts as a voxel classifier, where an input image patch centered at the voxel is generated as input to the DCNNs. An image patch has three channels that are mapped from a region-of-interest containing the image plane of the voxel and the two adjacent image planes. Six different types of spectral input image datasets were derived using two dual-energy CT images, two virtual monochromatic images, and two material images. An ensemble DCNN was constructed by use of a meta-classifier that combines the output of multiple DCNNs, each of which was trained with a different type of multi-spectral image patches. The electronically cleansed CTC images were calculated by removal of regions classified as other than soft tissue, followed by a colon surface reconstruction. For pilot evaluation, 359 volumes of interest (VOIs) representing sources of subtraction artifacts observed in current EC schemes were sampled from 30 clinical CTC cases. Preliminary results showed that the ensemble DCNN can yield high accuracy in labeling of the VOIs, indicating that deep learning of multi-spectral EC with multi-slice imaging could accurately remove residual fecal materials from CTC images without generating major EC artifacts.

  3. Distributed Human Intelligence for Colonic Polyp Classification in Computer-aided Detection for CT Colonography

    PubMed Central

    Nguyen, Tan B.; Wang, Shijun; Anugu, Vishal; Rose, Natalie; McKenna, Matthew; Petrick, Nicholas; Burns, Joseph E.

    2012-01-01

    Purpose: To assess the diagnostic performance of distributed human intelligence for the classification of polyp candidates identified with computer-aided detection (CAD) for computed tomographic (CT) colonography. Materials and Methods: This study was approved by the institutional Office of Human Subjects Research. The requirement for informed consent was waived for this HIPAA-compliant study. CT images from 24 patients, each with at least one polyp of 6 mm or larger, were analyzed by using CAD software to identify 268 polyp candidates. Twenty knowledge workers (KWs) from a crowdsourcing platform labeled each polyp candidate as a true or false polyp. Two trials involving 228 KWs were conducted to assess reproducibility. Performance was assessed by comparing the area under the receiver operating characteristic curve (AUC) of KWs with the AUC of CAD for polyp classification. Results: The detection-level AUC for KWs was 0.845 ± 0.045 (standard error) in trial 1 and 0.855 ± 0.044 in trial 2. These were not significantly different from the AUC for CAD, which was 0.859 ± 0.043. When polyp candidates were stratified by difficulty, KWs performed better than CAD on easy detections; AUCs were 0.951 ± 0.032 in trial 1, 0.966 ± 0.027 in trial 2, and 0.877 ± 0.048 for CAD (P = .039 for trial 2). KWs who participated in both trials showed a significant improvement in performance going from trial 1 to trial 2; AUCs were 0.759 ± 0.052 in trial 1 and 0.839 ± 0.046 in trial 2 (P = .041). Conclusion: The performance of distributed human intelligence is not significantly different from that of CAD for colonic polyp classification. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110938/-/DC1 PMID:22274839

  4. Distributed human intelligence for colonic polyp classification in computer-aided detection for CT colonography.

    PubMed

    Nguyen, Tan B; Wang, Shijun; Anugu, Vishal; Rose, Natalie; McKenna, Matthew; Petrick, Nicholas; Burns, Joseph E; Summers, Ronald M

    2012-03-01

    To assess the diagnostic performance of distributed human intelligence for the classification of polyp candidates identified with computer-aided detection (CAD) for computed tomographic (CT) colonography. This study was approved by the institutional Office of Human Subjects Research. The requirement for informed consent was waived for this HIPAA-compliant study. CT images from 24 patients, each with at least one polyp of 6 mm or larger, were analyzed by using CAD software to identify 268 polyp candidates. Twenty knowledge workers (KWs) from a crowdsourcing platform labeled each polyp candidate as a true or false polyp. Two trials involving 228 KWs were conducted to assess reproducibility. Performance was assessed by comparing the area under the receiver operating characteristic curve (AUC) of KWs with the AUC of CAD for polyp classification. The detection-level AUC for KWs was 0.845 ± 0.045 (standard error) in trial 1 and 0.855 ± 0.044 in trial 2. These were not significantly different from the AUC for CAD, which was 0.859 ± 0.043. When polyp candidates were stratified by difficulty, KWs performed better than CAD on easy detections; AUCs were 0.951 ± 0.032 in trial 1, 0.966 ± 0.027 in trial 2, and 0.877 ± 0.048 for CAD (P = .039 for trial 2). KWs who participated in both trials showed a significant improvement in performance going from trial 1 to trial 2; AUCs were 0.759 ± 0.052 in trial 1 and 0.839 ± 0.046 in trial 2 (P = .041). The performance of distributed human intelligence is not significantly different from that of CAD for colonic polyp classification. © RSNA.

  5. Low-dose dual-energy electronic cleansing for fecal-tagging CT Colonography

    NASA Astrophysics Data System (ADS)

    Cai, Wenli; Zhang, Da; Lee, June-Goo; Yoshida, Hiroyuki

    2013-03-01

    Dual-energy electronic cleansing (DE-EC) provides a promising means for cleansing the tagged fecal materials in fecaltagging CT colonography (CTC). However, the increased radiation dose due to the double exposures in dual-energy CTC (DE-CTC) scanning is a major limitation for the use of DE-EC in clinical practice. The purpose of this study was to develop and evaluate a low-dose DE-EC scheme in fecal-tagging DE-CTC. In this study, a custom-made anthropomorphic colon phantom, which was filled with simulated tagged materials by non-ionic iodinated contrast agent (Omnipaque iohexol, GE Healthcare), was scanned by a dual-source CT scanner (SOMATON Definition Flash, Siemens Healthcare) at two photon energies: 80 kVp and 140 kVp with nine different tube current settings ranging from 12 to 74 mAs for 140 kVp, and then reconstructed by soft-tissue reconstruction kernel (B30f). The DE-CTC images were subjected to a low-dose DE-EC scheme. First, our image-space DE-CTC denoising filter was applied for reduction of image noise. Then, the noise-reduced images were processed by a virtual lumen tagging method for reduction of partial volume effect and tagging inhomogeneity. The results were compared with the registered CTC images of native phantom without fillings. Preliminary results showed that our low-dose DE-EC scheme achieved the cleansing ratios, defined by the proportion of the cleansed voxels in the tagging mask, between 93.18% (12 mAs) and 96.62% (74 mAs). Also, the soft-tissue preservation ratios, defined by the proportion of the persevered voxels in the soft-tissue mask, were maintained in the range between 94.67% and 96.41%.

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

    PubMed

    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

    2017-07-05

    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.

  7. Dual-energy electronic cleansing for non-cathartic CT colonography: a phantom study

    NASA Astrophysics Data System (ADS)

    Cai, Wenli; Liu, Bob; Yoshida, Hiroyuki

    2010-03-01

    Partial volume effect and inhomogeneity are two major causes of artifacts in electronic cleansing (EC) for non-cathartic CT colonography (CTC). Our purpose was to develop a novel method of EC for non-cathartic dual-energy CTC (DECTC) using a subvoxel multi-spectral material classifier and a regional material decomposition method for differentiation of residual fecal materials from colonic soft-tissue structures. In this study, an anthropomorphic colon phantom, which was filled with a mixture of aqueous fiber (psyllium), ground foodstuff (cereal), and non-ionic iodinated agent (Omnipaque iohexol, GE Healthcare, Milwaukee, WI), was scanned by a dual-energy CT scanner (SOMATON, Siemens) with two photon energies: 80 kVp and 140 kVp. The DE-CTC images were subjected to a dual-energy EC (DE-EC) scheme, in which a multi-spectral material classifier was used to compute the fraction of each material within one voxel by an expectation-maximization (EM) algorithm. This was followed by a regional material segmentation method for identifying of homogeneous sub-regions (tiles) as fecal materials from other tissue types. The results were compared with the structural-analysis cleansing (SA-EC) method based upon the CTC images of native phantom without fillings. The mean cleansing ratio of the DE-EC scheme was 96.57+/-1.21% compared to 76.3+/-5.56% of the SA-EC scheme. The soft-tissue preservation ratio of the DE-EC scheme was 97.05%+/-0.64% compared to 99.25+/-0.77% of the SA-EC scheme.

  8. Towards a framework for analysis of eye-tracking studies in the three dimensional environment: a study of visual search by experienced readers of endoluminal CT colonography.

    PubMed

    Helbren, E; Halligan, S; Phillips, P; Boone, D; Fanshawe, T R; Taylor, S A; Manning, D; Gale, A; Altman, D G; Mallett, S

    2014-05-01

    Eye tracking in three dimensions is novel, but established descriptors derived from two-dimensional (2D) studies are not transferable. We aimed to develop metrics suitable for statistical comparison of eye-tracking data obtained from readers of three-dimensional (3D) "virtual" medical imaging, using CT colonography (CTC) as a typical example. Ten experienced radiologists were eye tracked while observing eight 3D endoluminal CTC videos. Subsequently, we developed metrics that described their visual search patterns based on concepts derived from 2D gaze studies. Statistical methods were developed to allow analysis of the metrics. Eye tracking was possible for all readers. Visual dwell on the moving region of interest (ROI) was defined as pursuit of the moving object across multiple frames. Using this concept of pursuit, five categories of metrics were defined that allowed characterization of reader gaze behaviour. These were time to first pursuit, identification and assessment time, pursuit duration, ROI size and pursuit frequency. Additional subcategories allowed us to further characterize visual search between readers in the test population. We propose metrics for the characterization of visual search of 3D moving medical images. These metrics can be used to compare readers' visual search patterns and provide a reproducible framework for the analysis of gaze tracking in the 3D environment. This article describes a novel set of metrics that can be used to describe gaze behaviour when eye tracking readers during interpretation of 3D medical images. These metrics build on those established for 2D eye tracking and are applicable to increasingly common 3D medical image displays.

  9. Deep transfer learning of virtual endoluminal views for the detection of polyps in CT colonography

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    Proper training of deep convolutional neural networks (DCNNs) requires large annotated image databases that are currently not available in CT colonography (CTC). In this study, we employed a deep transfer learning (DETALE) scheme to circumvent this problem in automated polyp detection for CTC. In our method, a DCNN that had been pre-trained with millions of non-medical images was adapted to identify polyps using virtual endoluminal images of the polyp candidates prompted by a computer-aided detection (CADe) system. For evaluation, 154 CTC cases with and without fecal tagging were divided randomly into a development set and an external validation set including 107 polyps >=6 mm in size. A CADe system was trained to detect polyp candidates using the development set, and the virtual endoluminal images of the polyp candidates were labeled manually into true-positive and several false-positive (FP) categories for transfer learning of the DCNN. Next, the trained CADe system was used to detect polyp candidates from the external validation set, and the DCNN reviewed their images to determine the final detections. The detection sensitivity of the standalone CADe system was 93% at 6.4 FPs per patient on average, whereas the DCNN reduced the number of FPs to 2.0 per patient without reducing detection sensitivity. Most of the remaining FP detections were caused by untagged stool. In fecal-tagged CTC cases, the detection sensitivity was 94% at only 0.78 FPs per patient on average. These preliminary results indicate that DETALE can yield substantial improvement in the accuracy of automated polyp detection in CTC.

  10. Deep learning for electronic cleansing in dual-energy CT colonography

    NASA Astrophysics Data System (ADS)

    Tachibana, Rie; Näppi, Janne J.; Hironakaa, Toru; Kim, Se Hyung; Yoshida, Hiroyuki

    2016-03-01

    The purpose of this study was to develop a novel deep-learning-based electronic cleansing (EC) method for dual-energy CT colonography (DE-CTC). In this method, an ensemble of deep convolutional neural networks (DCNNs) is used to classify each voxel of DE-CTC image volumes into one of five multi-material (MUMA) classes: luminal air, soft tissue, tagged fecal material, or a partial-volume boundary between air and tagging or that of soft tissue and tagging. Each DCNN acts as a voxel classifier. At each voxel, a region-of-interest (ROI) centered at the voxel is extracted. After mapping the pixels of the ROI to the input layer of a DCNN, a series of convolutional and max-pooling layers is used to extract features with increasing levels of abstraction. The output layer produces the probabilities at which the input voxel belongs to each of the five MUMA classes. To develop an ensemble of DCNNs, we trained multiple DCNNs based on multi-spectral image volumes derived from the DE-CTC images, including material decomposition images and virtual monochromatic images. The outputs of these DCNNs were then combined by means of a meta-classifier for precise classification of the voxels. Finally, the electronically cleansed CTC images were generated by removing regions that were classified as other than soft tissue, followed by colon surface reconstruction. Preliminary results based on 184,320 images sampled from 30 clinical CTC cases showed a higher accuracy in labeling these classes than that of our previous machine-learning methods, indicating that deep-learning-based multi-spectral EC can accurately remove residual fecal materials from CTC images without generating major EC artifacts.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Use of CT colonography in the English Bowel Cancer Screening Programme

    PubMed Central

    Plumb, Andrew A; Halligan, Steve; Nickerson, Claire; Bassett, Paul; Goddard, Andrew F; Taylor, Stuart A; Patnick, Julietta; Burling, David

    2014-01-01

    Objective To examine use of CT colonography (CTC) in the English Bowel Cancer Screening Programme (BCSP) and investigate detection rates. Design Retrospective analysis of routinely coded BCSP data. Guaiac faecal occult blood test (gFOBt)-positive screenees undergoing CTC from June 2006 to July 2012 as their first-line colonic investigation were included. Abnormalities found at CTC, subsequent polyp, adenoma and cancer detection and positive predictive value (PPV) were calculated. Detection rates were compared with those observed in gFOBt-positive screenees investigated by colonoscopy. Multilevel logistic regression was used to examine factors associated with variable detection. Results 2731 screenees underwent CTC. Colorectal cancer (CRC) or polyps were suspected in 1027 individuals (37.6%; 95% CI 33.8% to 41.4%); 911 of these underwent confirmatory testing. 124 screenees had CRC (4.5%) and 533 had polyps (19.5%), 468 adenomatous (17.1%). Overall detection was 24.1% (95% CI 21.5% to 26.6%) for CRC or polyps and 21.7% (95% CI 19.2% to 24.1%) for CRC or adenoma. Advanced neoplasia was detected in 504 screenees (18.5%; 95% CI 16.1% to 20.8%). PPV for CRC or polyp was 72.1% (95% CI 66.6% to 77.6%). By comparison, 9.0% of 72 817 screenees undergoing colonoscopy had cancer and 50.6% had polyps; advanced neoplasia was detected in 32.7%. CTC detection rates and PPV were higher at centres with experienced radiologists (>1000 examinations) and at high-volume centres (>175 cases/radiologist/annum). Centres using three-dimensional interpretation detected more neoplasia. Conclusions In the BCSP, detection rates after positive gFOBt are lower for CTC than colonoscopy, although populations undergoing the two tests are different. Centres with more experienced radiologists have higher detection and accuracy. Rigorous quality assurance of BCSP radiology is needed. PMID:23955527

  13. Deep ensemble learning of virtual endoluminal views for polyp detection in CT colonography

    NASA Astrophysics Data System (ADS)

    Umehara, Kensuke; Näppi, Janne J.; Hironaka, Toru; Regge, Daniele; Ishida, Takayuki; Yoshida, Hiroyuki

    2017-03-01

    Robust training of a deep convolutional neural network (DCNN) requires a very large number of annotated datasets that are currently not available in CT colonography (CTC). We previously demonstrated that deep transfer learning provides an effective approach for robust application of a DCNN in CTC. However, at high detection accuracy, the differentiation of small polyps from non-polyps was still challenging. In this study, we developed and evaluated a deep ensemble learning (DEL) scheme for reviewing of virtual endoluminal images to improve the performance of computer-aided detection (CADe) of polyps in CTC. Nine different types of image renderings were generated from virtual endoluminal images of polyp candidates detected by a conventional CADe system. Eleven DCNNs that represented three types of publically available pre-trained DCNN models were re-trained by transfer learning to identify polyps from the virtual endoluminal images. A DEL scheme that determines the final detected polyps by a review of the nine types of VE images was developed by combining the DCNNs using a random forest classifier as a meta-classifier. For evaluation, we sampled 154 CTC cases from a large CTC screening trial and divided the cases randomly into a training dataset and a test dataset. At 3.9 falsepositive (FP) detections per patient on average, the detection sensitivities of the conventional CADe system, the highestperforming single DCNN, and the DEL scheme were 81.3%, 90.7%, and 93.5%, respectively, for polyps ≥6 mm in size. For small polyps, the DEL scheme reduced the number of false positives by up to 83% over that of using a single DCNN alone. These preliminary results indicate that the DEL scheme provides an effective approach for improving the polyp detection performance of CADe in CTC, especially for small polyps.

  14. Objective and Subjective Intrapatient Comparison of Iohexol Versus Diatrizoate for Bowel Preparation Quality at CT Colonography.

    PubMed

    Johnson, Brandon; Hinshaw, J Louis; Robbins, Jessica B; Pickhardt, Perry J

    2016-06-01

    The purpose of this study is to objectively and subjectively compare nonionic iohexol and ionic diatrizoate iodinated oral contrast agents as part of a cathartic bowel regimen within the same CT colonography (CTC) cohort, with otherwise identical preparations. In this retrospective study, 46 adults with no symptoms (mean age, 59.4 years; 26 men and 20 women) returning for follow-up CTC over a 9-month interval underwent the same bowel preparation with the exception of 75 mL of iohexol 350 in place of 60 mL of diatrizoate. All other preparation components (bisacodyl, magnesium citrate, and 2% barium) remained constant. Objective volumetric analysis of residual colonic fluid volume and fluid attenuation was performed. Additionally, two radiologists experienced with CTC who were blinded to the specific bowel preparation scored each of six colonic segments for adherent residual solid stool using a previously validated 4-point scale (0 for no stool; 1-3 for increasing residual stool). A paired t test was used for comparison of the cohorts. No clear clinically meaningful difference was found between the two preparations on overall objective or subjective evaluation. The mean (± SD) residual fluid volume was 173 ± 126 mL with the iohexol preparation and 130 ± 79 mL with the diatrizoate preparation (p = 0.02). The mean total colonic stool score was 2.5 (0.42/segment) with iohexol and 2.3 (0.38/segment) with diatrizoate (p = 0.69). The mean fluid attenuation was higher with iohexol (849 ± 270 HU) compared with diatrizoate (732 ± 168 HU) (p = 0.03). On the basis of this direct intrapatient comparison, we found that oral iohexol is a suitable alternative to diatrizoate for fluid tagging as part of a cathartic bowel preparation at CTC. Because this nonionic tagging agent is more palatable, less expensive, and likely safer than ionic diatrizoate, our CTC program now uses iohexol as the standard recommended regimen.

  15. Associations among Pericolonic Fat, Visceral Fat, and Colorectal Polyps on CT Colonography

    PubMed Central

    Liu, Jiamin; Pattanaik, Sanket; Yao, Jianhua; Dwyer, Andrew J.; Pickhardt, Perry J.; Choi, J. Richard; Summers, Ronald M.

    2014-01-01

    OBJECTIVE To determine the association between pericolonic fat and colorectal polyps using CT colonography (CTC). METHODS 1169 patients who underwent CTC and same day optical colonoscopy were assessed. Pericolonic fat was measured on CTC in a band surrounding the colon. Visceral adipose tissue volume was measured at the L2-L3 levels. Student t-tests, odds ratio, logistic regression, binomial statistics and weighted-kappa were performed to ascertain associations with the incidence of colorectal polyps. RESULTS Pericolonic fat volume fractions (PFVF) were 61.5±11.0% versus 58.1±11.5%, 61.6 ±11.1% versus 58.7±11.5%, and 62.4±10.6% versus 58.8±11.5% for patients with and without any polyps, adenomatous polyps, and hyperplastic polyps, respectively (p<0.0001). Similar trends were observed when examining visceral fat volume fractions (VFVF). When patients were ordered by quintiles of PFVF or VFVF, there were 2.49, 2.19 and 2.39-fold increases in odds ratio for the presence of any polyp, adenomatous polyps, or hyperplastic polyps from the first to the fifth quintile for PFVF, and 1.92, 2.00 and 1.71-fold increases in odds ratio for VFVF. Polyps tended to occur more commonly in parts of the colon that had more PFVF than the spatially-adjusted average for patients in the highest quintile of VFVF. CONCLUSION Pericolonic fat accumulations, like visceral fat, are correlated with an increased risk of adenomatous and hyperplastic polyps. PMID:25558027

  16. Frequency analysis of gaze points with CT colonography interpretation using eye gaze tracking system

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Shoko; Tamashiro, Wataru; Sato, Mitsuru; Okajima, Mika; Ogura, Toshihiro; Doi, Kunio

    2017-03-01

    It is important to investigate eye tracking gaze points of experts, in order to assist trainees in understanding of image interpretation process. We investigated gaze points of CT colonography (CTC) interpretation process, and analyzed the difference in gaze points between experts and trainees. In this study, we attempted to understand how trainees can be improved to a level achieved by experts in viewing of CTC. We used an eye gaze point sensing system, Gazefineder (JVCKENWOOD Corporation, Tokyo, Japan), which can detect pupil point and corneal reflection point by the dark pupil eye tracking. This system can provide gaze points images and excel file data. The subjects are radiological technologists who are experienced, and inexperienced in reading CTC. We performed observer studies in reading virtual pathology images and examined observer's image interpretation process using gaze points data. Furthermore, we examined eye tracking frequency analysis by using the Fast Fourier Transform (FFT). We were able to understand the difference in gaze points between experts and trainees by use of the frequency analysis. The result of the trainee had a large amount of both high-frequency components and low-frequency components. In contrast, both components by the expert were relatively low. Regarding the amount of eye movement in every 0.02 second we found that the expert tended to interpret images slowly and calmly. On the other hand, the trainee was moving eyes quickly and also looking for wide areas. We can assess the difference in the gaze points on CTC between experts and trainees by use of the eye gaze point sensing system and based on the frequency analysis. The potential improvements in CTC interpretation for trainees can be evaluated by using gaze points data.

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

    PubMed

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

    2017-10-03

    To identify the top 100 cited articles, which focused on CT colonography. The top 100 articles could then be analyzed to get an idea of which factors resulted in highly cited works, and to establish trends in CTC research. Web of Science search was used to create a database of scientific journals using our search terms. A total of 10597 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 2 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 73-1179, and citations per year ranged from 4.5-84.21. Articles were published across 22 journals, most commonly Radiology (n=37) and American Journal of Roentgenology (n=19). Authors contributed from 1-20 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.

  18. Automated detection of colorectal lesions with dual-energy CT colonography

    NASA Astrophysics Data System (ADS)

    Näppi, Janne J.; Kim, Se Hyung; Yoshida, Hiroyuki

    2012-03-01

    Conventional single-energy computed tomography colonography (CTC) tends to miss polyps 6 - 9 mm in size and flat lesions. Dual-energy CTC (DE-CTC) provides more complete information about the chemical composition of tissue than does conventional CTC. We developed an automated computer-aided detection (CAD) scheme for detecting colorectal lesions in which dual-energy features were used to identify different bowel materials and their partial-volume artifacts. Based on these features, the dual-energy CAD (DE-CAD) scheme extracted the region of colon by use of a lumen-tracking method, detected lesions by use of volumetric shape features, and reduced false positives by use of a statistical classifier. For validation, 20 patients were prepared for DE-CTC by use of reduced bowel cleansing and orally administered fecal tagging with iodine and/or barium. The DE-CTC was performed in dual positions by use of a dual-energy CT scanner (SOMATOM Definition, Siemens) at 140 kVp and 80 kVp energy levels. The lesions identified by subsequent same-day colonoscopy were correlated with the DE-CTC data. The detection accuracies of the DE-CAD and conventional CAD schemes were compared by use of leave-one-patient-out evaluation and a bootstrap analysis. There were 25 colonoscopy-confirmed lesions: 22 were 6 - 9 mm and 3 were flat lesions >=10 mm in size. The DE-CAD scheme detected the large flat lesions and 95% of the 6 - 9 mm lesions with 9.9 false positives per patient. The improvement in detection accuracy by the DE-CAD was statistically significant.

  19. Screening CT Colonography: Multicenter Survey of Patient Experience, Preference, and Potential Impact on Adherence

    PubMed Central

    Pooler, B. Dustin; Baumel, Mark J.; Cash, Brooks D.; Moawad, Fouad J.; Riddle, Mark S.; Patrick, Amy M.; Damiano, Mark; Lee, Matthew H.; Kim, David H.; del Rio, Alejandro Muñoz; Pickhardt, Perry J.

    2013-01-01

    OBJECTIVE Prior research indicates CT colonography (CTC) would be a cost-effective colorectal cancer (CRC) screening test if widespread availability were to increase overall CRC screening adherence rates. The primary aims of this multicenter study were to evaluate patient experience and satisfaction with CTC screening and compare preference against screening colonoscopy. MATERIALS AND METHODS A 12-question survey instrument measuring pretest choice, experience, and satisfaction was given to a consecutive cohort of adults undergoing CTC screening in three disparate screening settings: university academic center, military medical center, and community practice. The study cohort was composed of individuals voluntarily participating in clinical CTC screening programs. RESULTS A total of 1417 patients responded to the survey. The top reasons for choosing CTC for screening included “noninvasiveness” (68.0%), “avoidance of sedation/anesthesia” (63.1%), “ability to drive after the test” (49.2%), “avoidance of optical colonoscopy risks” (46.9%), and “identifying abnormalities outside the colon” (43.3%). Only 7.2% of patients reported pain during the CTC examination and only 2.5% reported greater than moderate discomfort. Of 441 patients who had experienced both CTC and optical colonoscopy, 77.1% preferred CTC and 13.8% preferred optical colonoscopy. Of all patients, 29.6% indicated that they may not have undergone optical colonoscopy screening if CTC were not available. Of all patients, 92.9% labeled their overall experience with CTC as “excellent” or “good,” and 93.0% indicated they would choose CTC for their next screening. CONCLUSION Respondents reported a very high satisfaction level with CTC, and those who had experienced both modalities indicated a preference for CTC over optical colonoscopy. These results suggest that CTC has the potential to increase adherence to CRC screening guidelines if widely available. PMID:22623549

  20. Crouzon syndrome associated with acanthosis nigricans: prenatal 2D and 3D ultrasound findings and postnatal 3D CT findings

    PubMed Central

    Nørgaard, Pernille; Hagen, Casper Petri; Hove, Hanne; Dunø, Morten; Nissen, Kamilla Rothe; Kreiborg, Sven; Jørgensen, Finn Stener

    2012-01-01

    Crouzon syndrome with acanthosis nigricans (CAN) is a very rare condition with an approximate prevalence of 1 per 1 million newborns. We add the first report on prenatal 2D and 3D ultrasound findings in CAN. In addition we present the postnatal 3D CT findings. The diagnosis was confirmed by molecular testing. PMID:23986840

  1. Crouzon syndrome associated with acanthosis nigricans: prenatal 2D and 3D ultrasound findings and postnatal 3D CT findings.

    PubMed

    Nørgaard, Pernille; Hagen, Casper Petri; Hove, Hanne; Dunø, Morten; Nissen, Kamilla Rothe; Kreiborg, Sven; Jørgensen, Finn Stener

    2012-01-01

    Crouzon syndrome with acanthosis nigricans (CAN) is a very rare condition with an approximate prevalence of 1 per 1 million newborns. We add the first report on prenatal 2D and 3D ultrasound findings in CAN. In addition we present the postnatal 3D CT findings. The diagnosis was confirmed by molecular testing.

  2. Colonic distention at CT colonography: randomized evaluation of both IV hyoscine butylbromide and automated carbon dioxide insufflation.

    PubMed

    Nagata, Koichi; Fujiwara, Masanori; Shimamoto, Takeshi; Iida, Nao; Mogi, Tomohiro; Mitsushima, Toru

    2015-01-01

    The purpose of this article is to evaluate the efficacy of IV hyoscine butylbromide as a bowel relaxant and automated carbon dioxide insufflation in CT colonography in terms of colonic distention and perceived burden. SUBJECTS AND METHODS; Two hundred twenty-four participants were randomly allocated to one of four groups: control (no bowel relaxant and IV saline placebo before CT colonography with manual carbon dioxide insufflation), hyoscine butylbromide (IV hyoscine butylbromide before examination with manual carbon dioxide insufflation), automated (no bowel relaxant before examination with automated carbon dioxide insufflation), and combined (hyoscine butylbromide before examination with automated carbon dioxide insufflation). The degree of colonic distention on a 4-point scale, examination time, and participants' satisfaction, as measured by their responses to a questionnaire, were assessed. The mean distention grades of all the colonic segments and both positions were 3.22 in the control group, 3.28 in the hyoscine butylbromide group, 3.77 in the automated group, and 3.74 in the combined group. Compared with manual carbon dioxide insufflation, automated carbon dioxide insufflation significantly improved the clinical adequacy of colonic distention and shortened examination time. No statistically significant difference was seen in the clinical adequacy of distention between participants who received hyoscine butylbromide and those who did not, or in examination time. Overall, the participants' experiences were not different. Colonic distention was statistically significantly improved by automated carbon dioxide insufflation, but not by the administration of hyoscine butylbromide. The participants' tolerance was similar in each group.

  3. Fast 3D multiple fan-beam CT systems

    NASA Astrophysics Data System (ADS)

    Kohlbrenner, Adrian; Haemmerle, Stefan; Laib, Andres; Koller, Bruno; Ruegsegger, Peter

    1999-09-01

    Two fast, CCD-based three-dimensional CT scanners for in vivo applications have been developed. One is designed for small laboratory animals and has a voxel size of 20 micrometer, while the other, having a voxel size of 80 micrometer, is used for human examinations. Both instruments make use of a novel multiple fan-beam technique: radiation from a line-focus X-ray tube is divided into a stack of fan-beams by a 28 micrometer pitch foil collimator. The resulting wedge-shaped X-ray field is the key to the instrument's high scanning speed and allows to position the sample close to the X-ray source, which makes it possible to build compact CT systems. In contrast to cone- beam scanners, the multiple fan-beam scanner relies on standard fan-beam algorithms, thereby eliminating inaccuracies in the reconstruction process. The projections from one single rotation are acquired within 2 min and are subsequently reconstructed into a 1024 X 1024 X 255 voxel array. Hence a single rotation about the sample delivers a 3D image containing a quarter of a billion voxels. Such volumetric images are 6.6 mm in height and can be stacked on top of each other. An area CCD sensor bonded to a fiber-optic light guide acts as a detector. Since no image intensifier, conventional optics or tapers are used throughout the system, the image is virtually distortion free. The scanner's high scanning speed and high resolution at moderately low radiation dose are the basis for reliable time serial measurements and analyses.

  4. Mosaic Decomposition: An Electronic Cleansing Method for Inhomogeneously Tagged Regions in Noncathartic CT Colonography

    PubMed Central

    Cai, Wenli; Lee, June-Goo; Zalis, Michael E.; Yoshida, Hiroyuki

    2015-01-01

    Electronic cleansing (EC) is a method that segments fecal material tagged by an X-ray-opaque oral contrast agent in computed tomographic colonography (CTC) images, and effectively removes the material for digitally cleansing the colon. In this study, we developed a novel EC method, called mosaic decomposition (MD), for reduction of the artifacts due to incomplete cleansing of inhomogeneously tagged fecal material in CTC images, especially in noncathartic CTC images. In our approach, the entire colonic region, including the residual fecal regions, was first decomposed into a set of local homogeneous regions, called tiles, after application of a 3-D watershed transform to the CTC images. Each tile was then subjected to a single-class support vector machine (SVM) classifier for soft-tissue discrimination. The feature set of the soft-tissue SVM classifier was selected by a genetic algorithm (GA). A scalar index, called a soft-tissue likelihood, is formulated for differentiation of the soft-tissue tiles from those of other materials. Then, EC based on MD, called MD-cleansing, is performed by first initializing of the level-set front with the classified tagged regions; the front is then evolved by use of a speed function that was designed, based on the soft-tissue index, to reserve the submerged soft-tissue structures while suppressing the residual fecal regions. The performance of the MD-cleansing method was evaluated by use of a phantom and of clinical cases. In the phantom evaluation, our MD-cleansing was trained with the supine (prone) scan and tested on the prone (supine) scan, respectively. In both cases, the sensitivity and specificity of classification were 100%. The average cleansing ratio was 90.6%, and the soft-tissue preservation ratio was 97.6%. In the clinical evaluation, 10 noncathartic CTC cases (20 scans) were collected, and the ground truth of a total of 2095 tiles was established by manual assignment of a material class to each tile. Five cases were

  5. Comparing CT colonography and flexible sigmoidoscopy: a randomised trial within a population-based screening programme.

    PubMed

    Regge, Daniele; Iussich, Gabriella; Segnan, Nereo; Correale, Loredana; Hassan, Cesare; Arrigoni, Arrigo; Asnaghi, Roberto; Bestagini, Piero; Bulighin, Gianmarco; Cassinis, Maria Carla; Ederle, Andrea; Ferraris, Andrea; Galatola, Giovanni; Gallo, Teresa; Gandini, Giovanni; Garretti, Licia; Martina, Maria Cristina; Molinar, Daniela; Montemezzi, Stefania; Morra, Lia; Motton, Massimiliano; Occhipinti, Pietro; Pinali, Lucia; Soardi, Gian Alberto; Senore, Carlo

    2017-08-01

    The role of CT colonography (CTC) as a colorectal cancer (CRC) screening test is uncertain. The aim of our trial was to compare participation and detection rate (DR) with sigmoidoscopy (flexible sigmoidoscopy (FS)) and CTC in a screening setting. We conducted two randomised clinical trials (RCTs). (1) Participation RCT: individuals, aged 58 years, living in Turin (Italy), were randomly assigned to be invited to FS or CTC screening; (2) detection RCT: residents in northern Italy, aged 58-60, giving their consent to recruitment, were randomly allocated to CTC or FS. Polyps ≥6 mm at CTC, or 'high-risk' distal lesions at FS, were referred for colonoscopy (TC). Participation rate (proportion of invitees examined); DR of advanced adenomas or CRC (advanced neoplasia (AN)). Participation was 30.4% (298/980) for CTC and 27.4% (267/976) for FS (relative risk (RR) 1.1; 95% CI 0.98 to 1.29). Among men, participation was higher with CTC than with FS (34.1% vs 26.5%, p=0.011). In the detection RCT, 2673 subjects had FS and 2595 had CTC: the AN DR was 4.8% (127/2673, including 9 CRCs) with FS and 5.1% (133/2595, including 10 CRCs) with CTC (RR 1.08; 95% CI 0.85 to 1.37). Distal AN DR was 3.9% (109/2673) with FS and 2.9% (76/2595) with CTC (RR 0.72; 95% CI 0.54 to 0.96); proximal AN DR was 1.2% (34/2595) for FS vs 2.7% (69/2595) for CTC (RR 2.06; 95% CI 1.37 to 3.10). Participation and DR for FS and CTC were comparable. AN DR was twice as high in the proximal colon and lower in the distal colon with CTC than with FS. Men were more likely to participate in CTC screening. NCT01739608; Pre-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  6. Structure-analysis method for electronic cleansing in cathartic and noncathartic CT colonography.

    PubMed

    Cai, Wenli; Zalis, Michael E; Näppi, Janne; Harris, Gordon J; Yoshida, Hiroyuki

    2008-07-01

    Electronic cleansing (EC) is an emerging method for segmentation of fecal material in CT colonography (CTC) that is used for reducing or eliminating the requirement for cathartic bowel preparation and hence for improving patients' adherence to recommendations for colon cancer screening. In EC, feces tagged by an x-ray-opaque oral contrast agent are removed from the CTC images, effectively cleansing the colon after image acquisition. Existing EC approaches tend to suffer from the following cleansing artifacts: degradation of soft-tissue structures because of pseudo-enhancement caused by the surrounding tagged fecal materials, and pseudo soft-tissue structures and false fistulas caused by partial volume effects at the boundary between the air lumen and the tagged regions, called the air-tagging boundary (AT boundary). In this study, we developed a novel EC method, called structure-analysis cleansing, which effectively avoids these cleansing artifacts. In our method, submerged soft-tissue structures are recognized by their local morphologic signatures that are characterized based on the eigenvalues of a three-dimensional Hessian matrix. A structure-enhancement function is formulated for enhancing of the soft-tissue structures. In addition, thin folds sandwiched between the air lumen and tagged regions are enhanced by analysis of the local roughness based on multi-scale volumetric curvedness. Both values of the structure-enhancement function and the local roughness are integrated into the speed function of a level set method for delineating the tagged fecal materials. Thus, submerged soft-tissue structures as well as soft-tissue structures adhering to the tagged regions are preserved, whereas the tagged regions are removed along with the associated AT boundaries from CTC images. Evaluation of the quality of the cleansing based on polyps and folds in a colon phantom, as well as on polyps in clinical cathartic and noncathartic CTC cases with fluid and stool tagging

  7. Structure-analysis method for electronic cleansing in cathartic and noncathartic CT colonography

    PubMed Central

    Cai, Wenli; Zalis, Michael E.; Näppi, Janne; Harris, Gordon J.; Yoshida, Hiroyuki

    2008-01-01

    Electronic cleansing (EC) is an emerging method for segmentation of fecal material in CT colonography (CTC) that is used for reducing or eliminating the requirement for cathartic bowel preparation and hence for improving patients’ adherence to recommendations for colon cancer screening. In EC, feces tagged by an x-ray-opaque oral contrast agent are removed from the CTC images, effectively cleansing the colon after image acquisition. Existing EC approaches tend to suffer from the following cleansing artifacts: degradation of soft-tissue structures because of pseudo-enhancement caused by the surrounding tagged fecal materials, and pseudo soft-tissue structures and false fistulas caused by partial volume effects at the boundary between the air lumen and the tagged regions, called the air-tagging boundary (AT boundary). In this study, we developed a novel EC method, called structure-analysis cleansing, which effectively avoids these cleansing artifacts. In our method, submerged soft-tissue structures are recognized by their local morphologic signatures that are characterized based on the eigenvalues of a three-dimensional Hessian matrix. A structure-enhancement function is formulated for enhancing of the soft-tissue structures. In addition, thin folds sandwiched between the air lumen and tagged regions are enhanced by analysis of the local roughness based on multi-scale volumetric curvedness. Both values of the structure-enhancement function and the local roughness are integrated into the speed function of a level set method for delineating the tagged fecal materials. Thus, submerged soft-tissue structures as well as soft-tissue structures adhering to the tagged regions are preserved, whereas the tagged regions are removed along with the associated AT boundaries from CTC images. Evaluation of the quality of the cleansing based on polyps and folds in a colon phantom, as well as on polyps in clinical cathartic and noncathartic CTC cases with fluid and stool tagging

  8. Structure-analysis method for electronic cleansing in cathartic and noncathartic CT colonography.

    PubMed

    Cai, Wenli; Zalis, Michael E; Näppi, Janne; Harris, Gordon J; Yoshida, Hiroyuki

    2008-07-01

    Electronic cleansing (EC) is an emerging method for segmentation of fecal material in CT colonography (CTC) that is used for reducing or eliminating the requirement for cathartic bowel preparation and hence for improving patients' adherence to recommendations for colon cancer screening. In EC, feces tagged by an x-ray-opaque oral contrast agent are removed from the CTC images, effectively cleansing the colon after image acquisition. Existing EC approaches tend to suffer from the following cleansing artifacts: degradation of soft-tissue structures because of pseudo-enhancement caused by the surrounding tagged fecal materials, and pseudo soft-tissue structures and false fistulas caused by partial volume effects at the boundary between the air lumen and the tagged regions, called the air-tagging boundary (AT boundary). In this study, we developed a novel EC method, called structure-analysis cleansing, which effectively avoids these cleansing artifacts. In our method, submerged soft-tissue structures are recognized by their local morphologic signatures that are characterized based on the eigenvalues of a three-dimensional Hessian matrix. A structure-enhancement function is formulated for enhancing of the soft-tissue structures. In addition, thin folds sandwiched between the air lumen and tagged regions are enhanced by analysis of the local roughness based on multi-scale volumetric curvedness. Both values of the structure-enhancement function and the local roughness are integrated into the speed function of a level set method for delineating the tagged fecal materials. Thus, submerged soft-tissue structures as well as soft-tissue structures adhering to the tagged regions are preserved, whereas the tagged regions are removed along with the associated AT boundaries from CTC images. Evaluation of the quality of the cleansing based on polyps and folds in a colon phantom, as well as on polyps in clinical cathartic and noncathartic CTC cases with fluid and stool tagging

  9. Intra-individual comparison of magnesium citrate and sodium phosphate for bowel preparation at CT colonography

    PubMed Central

    Bannas, Peter; Bakke, Joshua; Munoz del Rio, Alejandro; Pickhardt, Perry 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. PMID:25239789

  10. Reduced cathartic bowel preparation for CT colonography: prospective comparison of 2-L polyethylene glycol and magnesium citrate.

    PubMed

    Keedy, Alexander W; Yee, Judy; Aslam, Rizwan; Weinstein, Stefanie; Landeras, Luis A; Shah, Janak N; McQuaid, Kenneth R; Yeh, Benjamin M

    2011-10-01

    To prospectively compare adequacy of colonic cleansing, adequacy of solid stool and fluid tagging, and patient acceptance by using reduced-volume, 2-L polyethylene glycol (PEG) versus magnesium citrate bowel preparations for CT colonography. This study was approved by the institutional Committee on Human Research and was compliant with HIPAA; all patients provided written consent. In this randomized, investigator-blinded study, 50 patients underwent oral preparation with either a 2-L PEG or a magnesium citrate solution, tagging with oral contrast agents, and subsequent CT colonography and segmentally unblinded colonoscopy. The residual stool (score 0 [best] to 3 [worst]) and fluid (score 0 [best] to 4 [worst]) burden and tagging adequacy were qualitatively assessed. Residual fluid attenuation was recorded as a quantitative measure of tagging adequacy. Patients completed a tolerance questionnaire within 2 weeks of scanning. Preparations were compared for residual stool and fluid by using generalized estimating equations; the Mann-Whitney test was used to compare the qualitative tagging score, mean residual fluid attenuation, and adverse effects assessed on the patient experience questionnaire. The mean residual stool (0.90 of three) and fluid burden (1.05 of four) scores for PEG were similar to those for magnesium citrate (0.96 [P = .58] and 0.98 [P = .48], respectively). However, the mean fecal and fluid tagging scores were significantly better for PEG (0.48 and 0.28, respectively) than for magnesium citrate (1.52 [P < .01] and 1.28 [P < .01], respectively). Mean residual fluid attenuation was higher for PEG (765 HU) than for magnesium citrate (443 HU, P = .01), and mean interpretation time was shorter for PEG (14.8 minutes) than for magnesium citrate (18.0 minutes, P = .04). Tolerance ratings were not significantly different between preparations. Reduced-volume PEG and magnesium citrate bowel preparations demonstrated adequate cleansing effectiveness for CT

  11. Reduced Cathartic Bowel Preparation for CT Colonography: Prospective Comparison of 2-L Polyethylene Glycol and Magnesium Citrate

    PubMed Central

    Keedy, Alexander W.; Aslam, Rizwan; Weinstein, Stefanie; Landeras, Luis A.; Shah, Janak N.; McQuaid, Kenneth R.; Yeh, Benjamin M.

    2011-01-01

    Purpose: To prospectively compare adequacy of colonic cleansing, adequacy of solid stool and fluid tagging, and patient acceptance by using reduced-volume, 2-L polyethylene glycol (PEG) versus magnesium citrate bowel preparations for CT colonography. Materials and Methods: This study was approved by the institutional Committee on Human Research and was compliant with HIPAA; all patients provided written consent. In this randomized, investigator-blinded study, 50 patients underwent oral preparation with either a 2-L PEG or a magnesium citrate solution, tagging with oral contrast agents, and subsequent CT colonography and segmentally unblinded colonoscopy. The residual stool (score 0 [best] to 3 [worst]) and fluid (score 0 [best] to 4 [worst]) burden and tagging adequacy were qualitatively assessed. Residual fluid attenuation was recorded as a quantitative measure of tagging adequacy. Patients completed a tolerance questionnaire within 2 weeks of scanning. Preparations were compared for residual stool and fluid by using generalized estimating equations; the Mann-Whitney test was used to compare the qualitative tagging score, mean residual fluid attenuation, and adverse effects assessed on the patient experience questionnaire. Results: The mean residual stool (0.90 of three) and fluid burden (1.05 of four) scores for PEG were similar to those for magnesium citrate (0.96 [P = .58] and 0.98 [P = .48], respectively). However, the mean fecal and fluid tagging scores were significantly better for PEG (0.48 and 0.28, respectively) than for magnesium citrate (1.52 [P < .01] and 1.28 [P < .01], respectively). Mean residual fluid attenuation was higher for PEG (765 HU) than for magnesium citrate (443 HU, P = .01), and mean interpretation time was shorter for PEG (14.8 minutes) than for magnesium citrate (18.0 minutes, P = .04). Tolerance ratings were not significantly different between preparations. Conclusion: Reduced-volume PEG and magnesium citrate bowel preparations

  12. Image fusion in craniofacial virtual reality modeling based on CT and 3dMD photogrammetry.

    PubMed

    Xin, Pengfei; Yu, Hongbo; Cheng, Huanchong; Shen, Shunyao; Shen, Steve G F

    2013-09-01

    The aim of this study was to demonstrate the feasibility of building a craniofacial virtual reality model by image fusion of 3-dimensional (3D) CT models and 3 dMD stereophotogrammetric facial surface. A CT scan and stereophotography were performed. The 3D CT models were reconstructed by Materialise Mimics software, and the stereophotogrammetric facial surface was reconstructed by 3 dMD patient software. All 3D CT models were exported as Stereo Lithography file format, and the 3 dMD model was exported as Virtual Reality Modeling Language file format. Image registration and fusion were performed in Mimics software. Genetic algorithm was used for precise image fusion alignment with minimum error. The 3D CT models and the 3 dMD stereophotogrammetric facial surface were finally merged into a single file and displayed using Deep Exploration software. Errors between the CT soft tissue model and 3 dMD facial surface were also analyzed. Virtual model based on CT-3 dMD image fusion clearly showed the photorealistic face and bone structures. Image registration errors in virtual face are mainly located in bilateral cheeks and eyeballs, and the errors are more than 1.5 mm. However, the image fusion of whole point cloud sets of CT and 3 dMD is acceptable with a minimum error that is less than 1 mm. The ease of use and high reliability of CT-3 dMD image fusion allows the 3D virtual head to be an accurate, realistic, and widespread tool, and has a great benefit to virtual face model.

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

    PubMed Central

    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 < 0.001). The average distance from the 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

  14. A new 3-D diagnosis strategy for duodenal malignant lesions using multidetector row CT, CT virtual duodenoscopy, duodenography, and 3-D multicholangiography.

    PubMed

    Sata, N; Endo, K; Shimura, K; Koizumi, M; Nagai, H

    2007-01-01

    Recent advances in multidetector row computed tomography (MD-CT) technology provide new opportunities for clinical diagnoses of various diseases. Here we assessed CT virtual duodenoscopy, duodenography, and three-dimensional (3D) multicholangiography created by MD-CT for clinical diagnosis of duodenal malignant lesions. The study involved seven cases of periduodenal carcinoma (four ampullary carcinomas, two duodenal carcinomas, one pancreatic carcinoma). Biliary contrast medium was administered intravenously, followed by intravenous administration of an anticholinergic agent and oral administration of effervescent granules for expanding the upper gastrointestinal tract. Following intravenous administration of a nonionic contrast medium, an upper abdominal MD-CT scan was performed in the left lateral position. Scan data were processed on a workstation to create CT virtual duodenoscopy, duodenography, 3D multicholangiography, and various postprocessing images, which were then evaluated for their effectiveness as preoperative diagnostic tools. Carcinoma location and extent were clearly demonstrated as defects or colored low-density areas in 3-D multicholangiography images and as protruding lesions in virtual duodenography and duodenoscopy images. These findings were confirmed using multiplanar or curved planar reformation images. In conclusion, CT virtual duodenoscopy, doudenography, 3-D multicholangiography, and various images created by MD-CT alone provided necessary and adequate preoperative diagnostic information.

  15. Current techniques in the performance, interpretation, and reporting of CT colonography.

    PubMed

    Poullos, Peter D; Beaulieu, Christopher F

    2010-04-01

    The technical objective of computed tomographic colonography (CTC) is to acquire high-quality computed tomography images of the cleansed, well-distended colon for polyp detection. In this article the authors provide an overview of the technical components of CTC, from preparation of the patient to acquisition of the imaging data and basic methods of interpretation. In each section, the best evidence for current practices and recommendations is reviewed. Each of the technical components must be optimized to achieve high sensitivity in polyp detection.

  16. 3D statistical shape models incorporating 3D random forest regression voting for robust CT liver segmentation

    NASA Astrophysics Data System (ADS)

    Norajitra, Tobias; Meinzer, Hans-Peter; Maier-Hein, Klaus H.

    2015-03-01

    During image segmentation, 3D Statistical Shape Models (SSM) usually conduct a limited search for target landmarks within one-dimensional search profiles perpendicular to the model surface. In addition, landmark appearance is modeled only locally based on linear profiles and weak learners, altogether leading to segmentation errors from landmark ambiguities and limited search coverage. We present a new method for 3D SSM segmentation based on 3D Random Forest Regression Voting. For each surface landmark, a Random Regression Forest is trained that learns a 3D spatial displacement function between the according reference landmark and a set of surrounding sample points, based on an infinite set of non-local randomized 3D Haar-like features. Landmark search is then conducted omni-directionally within 3D search spaces, where voxelwise forest predictions on landmark position contribute to a common voting map which reflects the overall position estimate. Segmentation experiments were conducted on a set of 45 CT volumes of the human liver, of which 40 images were randomly chosen for training and 5 for testing. Without parameter optimization, using a simple candidate selection and a single resolution approach, excellent results were achieved, while faster convergence and better concavity segmentation were observed, altogether underlining the potential of our approach in terms of increased robustness from distinct landmark detection and from better search coverage.

  17. Comparison of physical quality assurance between Scanora 3D and 3D Accuitomo 80 dental CT scanners.

    PubMed

    Ali, Ahmed S; Fteita, Dareen; Kulmala, Jarmo

    2015-01-01

    The use of cone beam computed tomography (CBCT) in dentistry has proven to be useful in the diagnosis and treatment planning of several oral and maxillofacial diseases. The quality of the resulting image is dictated by many factors related to the patient, unit, and operator. In this work, two dental CBCT units, namely Scanora 3D and 3D Accuitomo 80, were assessed and compared in terms of quantitative effective dose delivered to specific locations in a dosimetry phantom. Resolution and contrast were evaluated in only 3D Accuitomo 80 using special quality assurance phantoms. Scanora 3D, with less radiation time, showed less dosing values compared to 3D Accuitomo 80 (mean 0.33 mSv, SD±0.16 vs. 0.18 mSv, SD±0.1). Using paired t-test, no significant difference was found in Accuitomo two scan sessions (p>0.05), while it was highly significant in Scanora (p>0.05). The modulation transfer function value (at 2 lp/mm), in both measurements, was found to be 4.4%. The contrast assessment of 3D Accuitomo 80 in the two measurements showed few differences, for example, the grayscale values were the same (SD=0) while the noise level was slightly different (SD=0 and 0.67, respectively). The radiation dose values in these two CBCT units are significantly less than those encountered in systemic CT scans. However, the dose seems to be affected more by changing the field of view rather than the voltage or amperage. The low doses were at the expense of the image quality produced, which was still acceptable. Although the spatial resolution and contrast were inferior to the medical images produced in systemic CT units, the present results recommend adopting CBCTs in maxillofacial imaging because of low radiation dose and adequate image quality.

  18. Comparison of physical quality assurance between Scanora 3D and 3D Accuitomo 80 dental CT scanners

    PubMed Central

    Ali, Ahmed S.; Fteita, Dareen; Kulmala, Jarmo

    2015-01-01

    Background The use of cone beam computed tomography (CBCT) in dentistry has proven to be useful in the diagnosis and treatment planning of several oral and maxillofacial diseases. The quality of the resulting image is dictated by many factors related to the patient, unit, and operator. Materials and methods In this work, two dental CBCT units, namely Scanora 3D and 3D Accuitomo 80, were assessed and compared in terms of quantitative effective dose delivered to specific locations in a dosimetry phantom. Resolution and contrast were evaluated in only 3D Accuitomo 80 using special quality assurance phantoms. Results Scanora 3D, with less radiation time, showed less dosing values compared to 3D Accuitomo 80 (mean 0.33 mSv, SD±0.16 vs. 0.18 mSv, SD±0.1). Using paired t-test, no significant difference was found in Accuitomo two scan sessions (p>0.05), while it was highly significant in Scanora (p>0.05). The modulation transfer function value (at 2 lp/mm), in both measurements, was found to be 4.4%. The contrast assessment of 3D Accuitomo 80 in the two measurements showed few differences, for example, the grayscale values were the same (SD=0) while the noise level was slightly different (SD=0 and 0.67, respectively). Conclusions The radiation dose values in these two CBCT units are significantly less than those encountered in systemic CT scans. However, the dose seems to be affected more by changing the field of view rather than the voltage or amperage. The low doses were at the expense of the image quality produced, which was still acceptable. Although the spatial resolution and contrast were inferior to the medical images produced in systemic CT units, the present results recommend adopting CBCTs in maxillofacial imaging because of low radiation dose and adequate image quality. PMID:26091832

  19. Therapeutic response assessment using 3D ultrasound for hepatic metastasis from colorectal cancer: Application of a personalized, 3D-printed tumor model using CT images

    PubMed Central

    Choi, Ye Ra; Park, Sang Joon; Hur, Bo Yun; Han, Joon Koo

    2017-01-01

    Background & aims To evaluate accuracy and reliability of three-dimensional ultrasound (3D US) for response evaluation of hepatic metastasis from colorectal cancer (CRC) using a personalized 3D-printed tumor model. Methods Twenty patients with liver metastasis from CRC who underwent baseline and after chemotherapy CT, were retrospectively included. Personalized 3D-printed tumor models using CT were fabricated. Two radiologists measured volume of each 3D printing model using 3D US. With CT as a reference, we compared difference between CT and US tumor volume. The response evaluation was based on Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Results 3D US tumor volume showed no significant difference from CT volume (7.18 ± 5.44 mL, 8.31 ± 6.32 mL vs 7.42 ± 5.76 mL in CT, p>0.05). 3D US provided a high correlation coefficient with CT (r = 0.953, r = 0.97) as well as a high inter-observer intraclass correlation (0.978; 0.958–0.988). Regarding response, 3D US was in agreement with CT in 17 and 18 out of 20 patients for observer 1 and 2 with excellent agreement (κ = 0.961). Conclusions 3D US tumor volume using a personalized 3D-printed model is an accurate and reliable method for the response evaluation in comparison with CT tumor volume. PMID:28797089

  20. Computation of tooth axes of existent and missing teeth from 3D CT images.

    PubMed

    Wang, Yang; Wu, Lin; Guo, Huayan; Qiu, Tiantian; Huang, Yuanliang; Lin, Bin; Wang, Lisheng

    2015-12-01

    Orientations of tooth axes are important quantitative information used in dental diagnosis and surgery planning. However, their computation is a complex problem, and the existing methods have respective limitations. This paper proposes new methods to compute 3D tooth axes from 3D CT images for existent teeth with single root or multiple roots and to estimate 3D tooth axes from 3D CT images for missing teeth. The tooth axis of a single-root tooth will be determined by segmenting the pulp cavity of the tooth and computing the principal direction of the pulp cavity, and the estimation of tooth axes of the missing teeth is modeled as an interpolation problem of some quaternions along a 3D curve. The proposed methods can either avoid the difficult teeth segmentation problem or improve the limitations of existing methods. Their effectiveness and practicality are demonstrated by experimental results of different 3D CT images from the clinic.

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

    PubMed

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

    2015-01-01

    To quantify the incremental benefit of computer-assisted-detection (CAD) for polyps, for inexperienced readers versus experienced readers of CT colonography. 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. 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. 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.

  2. Value of 3-D CT in classifying acetabular fractures during orthopedic residency training.

    PubMed

    Garrett, Jeffrey; Halvorson, Jason; Carroll, Eben; Webb, Lawrence X

    2012-05-01

    The complex anatomy of the pelvis and acetabulum have historically made classification and interpretation of acetabular fractures difficult for orthopedic trainees. The addition of 3-dimensional (3-D) computed tomography (CT) scan has gained popularity in preoperative planning, identification, and education of acetabular fractures given their complexity. Therefore, the authors examined the value of 3-D CT compared with conventional radiography in classifying acetabular fractures at different levels of orthopedic training. Their hypothesis was that 3-D CT would improve correct identification of acetabular fractures compared with conventional radiography.The classic Letournel fracture pattern classification system was presented in quiz format to 57 orthopedic residents and 20 fellowship-trained orthopedic traumatologists. A case consisted of (1) plain radiographs and 2-dimensional axial CT scans or (2) 3-D CT scans. All levels of training showed significant improvement in classifying acetabular fractures with 3-D vs 2-D CT, with the greatest benefit from 3-D CT found in junior residents (postgraduate years 1-3).Three-dimensional CT scans can be an effective educational tool for understanding the complex spatial anatomy of the pelvis, learning acetabular fracture patterns, and correctly applying a widely accepted fracture classification system.

  3. Segmentation of the ovine lung in 3D CT Images

    NASA Astrophysics Data System (ADS)

    Shi, Lijun; Hoffman, Eric A.; Reinhardt, Joseph M.

    2004-04-01

    Pulmonary CT images can provide detailed information about the regional structure and function of the respiratory system. Prior to any of these analyses, however, the lungs must be identified in the CT data sets. A popular animal model for understanding lung physiology and pathophysiology is the sheep. In this paper we describe a lung segmentation algorithm for CT images of sheep. The algorithm has two main steps. The first step is lung extraction, which identifies the lung region using a technique based on optimal thresholding and connected components analysis. The second step is lung separation, which separates the left lung from the right lung by identifying the central fissure using an anatomy-based method incorporating dynamic programming and a line filter algorithm. The lung segmentation algorithm has been validated by comparing our automatic method to manual analysis for five pulmonary CT datasets. The RMS error between the computer-defined and manually-traced boundary is 0.96 mm. The segmentation requires approximately 10 minutes for a 512x512x400 dataset on a PC workstation (2.40 GHZ CPU, 2.0 GB RAM), while it takes human observer approximately two hours to accomplish the same task.

  4. Algorithm of pulmonary emphysema extraction using thoracic 3D CT images

    NASA Astrophysics Data System (ADS)

    Saita, Shinsuke; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Ohmatsu, Hironobu; Tominaga, Keigo; Eguchi, Kenji; Moriyama, Noriyuki

    2007-03-01

    Recently, due to aging and smoking, emphysema patients are increasing. The restoration of alveolus which was destroyed by emphysema is not possible, thus early detection of emphysema is desired. We describe a quantitative algorithm for extracting emphysematous lesions and quantitatively evaluate their distribution patterns using low dose thoracic 3-D CT images. The algorithm identified lung anatomies, and extracted low attenuation area (LAA) as emphysematous lesion candidates. Applying the algorithm to thoracic 3-D CT images and then by follow-up 3-D CT images, we demonstrate its potential effectiveness to assist radiologists and physicians to quantitatively evaluate the emphysematous lesions distribution and their evolution in time interval changes.

  5. [Virtual reality in MR colonography].

    PubMed

    Schoenfelder, D; Debatin, J F

    2000-03-01

    Early detection and subsequent removal of colorectal polyps have been shown to constitute an effective approach for decreasing the incidence of colorectal cancer. The lack of an ideal modality for colorectal polyp screening stimulated interest in the development of CT-colonography and MR-colonography. Both techniques allow the colon to be analyzed in a cross-sectional as well as a virtual endoscopic format. Causing no side-effects and not concerning for radiation exposure MR-colonography warrants further consideration. Additional to detecting polyps down to 6 mm in size the inner wall contour and the morphology of the colonic wall itself can be assessed. New developments like fecal tagging will increase patients acceptance comparing to other diagnostic techniques. In search of an ideal modality for polyp screening MR-colonography will become a potent option in the diagnostic arsenal.

  6. Accuracy of volume measurement using 3D ultrasound and development of CT-3D US image fusion algorithm for prostate cancer radiotherapy

    SciTech Connect

    Baek, Jihye; Huh, Jangyoung; Hyun An, So; Oh, Yoonjin; Kim, Myungsoo; Kim, DongYoung; Chung, Kwangzoo; Cho, Sungho; Lee, Rena

    2013-02-15

    Purpose: To evaluate the accuracy of measuring volumes using three-dimensional ultrasound (3D US), and to verify the feasibility of the replacement of CT-MR fusion images with CT-3D US in radiotherapy treatment planning. Methods: Phantoms, consisting of water, contrast agent, and agarose, were manufactured. The volume was measured using 3D US, CT, and MR devices. A CT-3D US and MR-3D US image fusion software was developed using the Insight Toolkit library in order to acquire three-dimensional fusion images. The quality of the image fusion was evaluated using metric value and fusion images. Results: Volume measurement, using 3D US, shows a 2.8 {+-} 1.5% error, 4.4 {+-} 3.0% error for CT, and 3.1 {+-} 2.0% error for MR. The results imply that volume measurement using the 3D US devices has a similar accuracy level to that of CT and MR. Three-dimensional image fusion of CT-3D US and MR-3D US was successfully performed using phantom images. Moreover, MR-3D US image fusion was performed using human bladder images. Conclusions: 3D US could be used in the volume measurement of human bladders and prostates. CT-3D US image fusion could be used in monitoring the target position in each fraction of external beam radiation therapy. Moreover, the feasibility of replacing the CT-MR image fusion to the CT-3D US in radiotherapy treatment planning was verified.

  7. Vascular Map Combined with CT Colonography for Evaluating Candidates for Laparoscopic Colorectal Surgery.

    PubMed

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

    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.

  8. Vascular Map Combined with CT Colonography for Evaluating Candidates for Laparoscopic Colorectal Surgery

    PubMed Central

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

    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. PMID:26175581

  9. 3D Biometrics for Hindfoot Alignment Using Weightbearing CT.

    PubMed

    Lintz, François; Welck, Matthew; Bernasconi, Alessio; Thornton, James; Cullen, Nicholas P; Singh, Dishan; Goldberg, Andy

    2017-06-01

    Hindfoot alignment on 2D radiographs can present anatomical and operator-related bias. In this study, software designed for weightbearing computed tomography (WBCT) was used to calculate a new 3D biometric tool: the Foot and Ankle Offset (FAO). We described the distribution of FAO in a series of data sets from clinically normal, varus, and valgus cases, hypothesizing that FAO values would be significantly different in the 3 groups. In this retrospective cohort study, 135 data sets (57 normal, 38 varus, 40 valgus) from WBCT (PedCAT; CurveBeam LLC, Warrington, PA) were obtained from a specialized foot and ankle unit. 3D coordinates of specific anatomical landmarks (weightbearing points of the calcaneus, of the first and fifth metatarsal heads and the highest and centermost point on the talar dome) were collected. These data were processed with the TALAS system (CurveBeam), which resulted in an FAO value for each case. Intraobserver and interobserver reliability were also assessed. In normal cases, the mean value for FAO was 2.3% ± 2.9%, whereas in varus and valgus cases, the mean was -11.6% ± 6.9% and 11.4% ± 5.7%, respectively, with a statistically significant difference among groups ( P < .001). The distribution of the normal population was Gaussian. The inter- and intraobserver reliability were 0.99 +/- 0.00 and 0.97 +/-0.02 Conclusions: This pilot study suggests that the FAO is an efficient tool for measuring hindfoot alignment using WBCT. Previously published research in this field has looked at WBCT by adapting 2D biometrics. The present study introduces the concept of 3D biometrics and describes an efficient, semiautomatic tool for measuring hindfoot alignment. Level III, retrospective comparative study.

  10. Evaluation of dose reduction and image quality in CT colonography: comparison of low-dose CT with iterative reconstruction and routine-dose CT with filtered back projection.

    PubMed

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

    2015-01-01

    To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the prone series (p < 0.01). Overall image quality and noise of low-dose CTC with iterative reconstruction were significantly improved compared to routine-dose CTC using filtered back projection. The lowest dose group had image quality comparable to routine-dose images. Low-dose CTC with iterative reconstruction reduces the radiation dose by 48.5 to 75.1% without image quality degradation compared to routine-dose CTC with filtered back projection. • Low-dose CTC reduces radiation dose ≥ 48.5% compared to routine-dose CTC. • Iterative reconstruction improves overall CTC image quality compared with FBP. • Iterative reconstruction reduces overall CTC image noise compared with FBP. • Automated exposure control with iterative reconstruction is useful for low-dose CTC.

  11. 3D Ultrasound Can Contribute to Planning CT to Define the Target for Partial Breast Radiotherapy

    SciTech Connect

    Berrang, Tanya S.; Truong, Pauline T. Popescu, Carmen; Drever, Laura; Kader, Hosam A.; Hilts, Michelle L.; Mitchell, Tracy; Soh, S.Y.; Sands, Letricia; Silver, Stuart; Olivotto, Ivo A.

    2009-02-01

    Purpose: The role of three-dimensional breast ultrasound (3D US) in planning partial breast radiotherapy (PBRT) is unknown. This study evaluated the accuracy of coregistration of 3D US to planning computerized tomography (CT) images, the seroma contouring consistency of radiation oncologists using the two imaging modalities and the clinical situations in which US was associated with improved contouring consistency compared to CT. Materials and Methods: Twenty consecutive women with early-stage breast cancer were enrolled prospectively after breast-conserving surgery. Subjects underwent 3D US at CT simulation for adjuvant RT. Three radiation oncologists independently contoured the seroma on separate CT and 3D US image sets. Seroma clarity, seroma volumes, and interobserver contouring consistency were compared between the imaging modalities. Associations between clinical characteristics and seroma clarity were examined using Pearson correlation statistics. Results: 3D US and CT coregistration was accurate to within 2 mm or less in 19/20 (95%) cases. CT seroma clarity was reduced with dense breast parenchyma (p = 0.035), small seroma volume (p < 0.001), and small volume of excised breast tissue (p = 0.01). US seroma clarity was not affected by these factors (p = NS). US was associated with improved interobserver consistency compared with CT in 8/20 (40%) cases. Of these 8 cases, 7 had low CT seroma clarity scores and 4 had heterogeneously to extremely dense breast parenchyma. Conclusion: 3D US can be a useful adjunct to CT in planning PBRT. Radiation oncologists were able to use US images to contour the seroma target, with improved interobserver consistency compared with CT in cases with dense breast parenchyma and poor CT seroma clarity.

  12. Enhancement of weakly tagged fecal materials in dual-energy CT colonography using spectral-driven iterative reconstruction technique

    NASA Astrophysics Data System (ADS)

    Nasirudin, Radin A.; Näppi, Janne J.; Hironaka, Toru; Tachibana, Rie; Yoshida, Hiroyuki

    2017-03-01

    Dual-energy computed tomography is used increasingly in CT colonography (CTC). The combination of computer-aided detection (CAD) and dual-energy CTC has a high clinical value because it can automatically detect clinically significant colonic lesions in CTC images with higher accuracy than does single-energy CTC. While CAD has demonstrated its ability to detect small polyps, its performance is highly dependent on the quality of the input images. The presence of artifacts such as beam hardening and image noise in ultra-low-dose CTC may severely degrade detection performance for small polyps. A further limitation to the effectiveness of CAD are the weakly tagged fecal materials in the colon that may cause false-positive detections. In this work, we developed a dual-energy method for enhancing the appearance of weakly tagged fecal materials in CTC images. The proposed method consists of two stages: 1) the detection of weakly tagged fecal materials by use of sinogram-based image decomposition and 2) the enhancement of the detected tagged fecal materials in the images using an iterative reconstruction method. In the first stage, the ultra-low-dose dual-energy projection data obtained from a CT scanner are decomposed into two basis materials - soft tissue and fecal-tagged material (iodine). Virtual monochromatic projection data are calculated from the material decomposition at a pre-determined energy. The iodine-decomposed sinogram and the virtual monochromatic projection data are then used as input to an iterative reconstruction method. In the second stage, virtual monochromatic images are reconstructed iteratively while the intensity of weakly tagged iodine in the images is enhanced. The performance of the proposed method was assessed qualitatively and quantitatively. Preliminary results show that our method effectively enhances the visual appearance of weakly tagged fecal materials in the reconstructed CT images while reducing noise and improving the overall quality of

  13. 3D CT spine data segmentation and analysis of vertebrae bone lesions.

    PubMed

    Peter, R; Malinsky, M; Ourednicek, P; Jan, J

    2013-01-01

    A method is presented aiming at detecting and classifying bone lesions in 3D CT data of human spine, via Bayesian approach utilizing Markov random fields. A developed algorithm for necessary segmentation of individual possibly heavily distorted vertebrae based on 3D intensity modeling of vertebra types is presented as well.

  14. Do prevalence expectations affect patterns of visual search and decision-making in interpreting CT colonography endoluminal videos?

    PubMed

    Fanshawe, Thomas R; Phillips, Peter; Plumb, Andrew; Helbren, Emma; Halligan, Steve; Taylor, Stuart A; Gale, Alastair; Mallett, Susan

    2016-01-01

    To assess the effect of expected abnormality prevalence on visual search and decision-making in CT colonography (CTC). 13 radiologists interpreted endoluminal CTC fly-throughs of the same group of 10 patient cases, 3 times each. Abnormality prevalence was fixed (50%), but readers were told, before viewing each group, that prevalence was either 20%, 50% or 80% in the population from which cases were drawn. Infrared visual search recording was used. Readers indicated seeing a polyp by clicking a mouse. Multilevel modelling quantified the effect of expected prevalence on outcomes. Differences between expected prevalence were not statistically significant for time to first pursuit of the polyp (median 0.5 s, each prevalence), pursuit rate when no polyp was on screen (median 2.7 s(-1), each prevalence) or number of mouse clicks [mean 0.75/video (20% prevalence), 0.93 (50%), 0.97 (80%)]. There was weak evidence of increased tendency to look outside the central screen area at 80% prevalence and reduction in positive polyp identifications at 20% prevalence. This study did not find a large effect of prevalence information on most visual search metrics or polyp identification in CTC. Further research is required to quantify effects at lower prevalence and in relation to secondary outcome measures. Prevalence effects in evaluating CTC have not previously been assessed. In this study, providing expected prevalence information did not have a large effect on diagnostic decisions or patterns of visual search.

  15. Information-Preserving Pseudo-Enhancement Correction for Non-Cathartic Low-Dose Dual-Energy CT Colonography.

    PubMed

    Näppi, Janne J; Tachibana, Rie; Regge, Daniele; Yoshida, Hiroyuki

    2014-09-01

    In CT colonography (CTC), orally administered positive-contrast fecal-tagging agents can cause artificial elevation of the observed radiodensity of adjacent soft tissue. Such pseudo-enhancement makes it challenging to differentiate polyps and folds reliably from tagged materials, and it is also present in dual-energy CTC (DE-CTC). We developed a method that corrects for pseudo-enhancement on DE-CTC images without distorting the dual-energy information contained in the data. A pilot study was performed to evaluate the effect of the method visually and quantitatively by use of clinical non-cathartic low-dose DE-CTC data from 10 patients including 13 polyps covered partially or completely by iodine-based fecal tagging. The results indicate that the proposed method can be used to reduce the pseudo-enhancement distortion of DE-CTC images without losing material-specific dual-energy information. The method has potential application in improving the accuracy of automated image-processing applications, such as computer-aided detection and virtual bowel cleansing in CTC.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Flexible sigmoidoscopy does not significantly increase polyp and cancer detection yield when used to supplement CT colonography.

    PubMed

    Selinger, C P; Mullender, J; Choudhury, S; Jones, P E; Sukumar, S; Ramesh, J

    2012-01-01

    Flexible sigmoidoscopy (FS) increases polyp and carcinoma detection in addition to double contrast barium enema (DCBE). However, CT colonography (CTC) is now the preferred technique. Our aim was to explore whether FS increases polyp and carcinoma detection rates when used in addition to CTC. Patients who underwent FS and CTC between 2007 and 2009 were included and data were collected from patient records. Yields of polyp, adenoma and carcinoma detection were calculated for FS and CTC. In a cohort of 294 patients, CTC detected 36 patients with carcinomas while FS detected 28. One rectal cancer not seen on CTC was diagnosed by FS. Polyps were seen by CTC in 66 and FS in 45 patients. In 5 patients FS found polyps that were not detected by CTC; 3 of which were small adenomas. FS detected extra adenomas or carcinomas in 1.36% (4/294). Adding FS to CTC neither increased the cancer nor the polyp detection yield significantly. This first study investigating the use of FS in addition to CTC detected little additional pathology. The routine use of FS as a supplement to CTC for adenoma and carcinoma detection is of questionable utility. Copyright © 2011 S. Karger AG, Basel.

  19. In vivo 3D PIXE-micron-CT imaging of Drosophila melanogaster using a contrast agent

    NASA Astrophysics Data System (ADS)

    Matsuyama, Shigeo; Hamada, Naoki; Ishii, Keizo; Nozawa, Yuichiro; Ohkura, Satoru; Terakawa, Atsuki; Hatori, Yoshinobu; Fujiki, Kota; Fujiwara, Mitsuhiro; Toyama, Sho

    2015-04-01

    In this study, we developed a three-dimensional (3D) computed tomography (CT) in vivo imaging system for imaging small insects with micrometer resolution. The 3D CT imaging system, referred to as 3D PIXE-micron-CT (PIXEμCT), uses characteristic X-rays produced by ion microbeam bombardment of a metal target. PIXEμCT was used to observe the body organs and internal structure of a living Drosophila melanogaster. Although the organs of the thorax were clearly imaged, the digestive organs in the abdominal cavity could not be clearly discerned initially, with the exception of the rectum and the Malpighian tubule. To enhance the abdominal images, a barium sulfate powder radiocontrast agent was added. For the first time, 3D images of the ventriculus of a living D. melanogaster were obtained. Our results showed that PIXEμCT can provide in vivo 3D-CT images that reflect correctly the structure of individual living organs, which is expected to be very useful in biological research.

  20. Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

    PubMed Central

    2011-01-01

    Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides. Methods In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast) and preoperative (radiographic template) models, obtained by both CT and optical scanning processes. Results A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates. Conclusions The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology. PMID:21338504

  1. CAD of colon cancer on CT colonography cases without cathartic bowel preparation.

    PubMed

    Linguraru, Marius George; Zhao, Shan; Van Uitert, Robert L; Liu, Jiamin; Fletcher, Joel G; Manduca, Armando; Summers, Ronald M

    2008-01-01

    Computer-aided diagnosis (CAD) systems must show sufficient versatility to produce robust analysis on a large variety of data. In the case of colonography, CAD has not been designed to cope with the presence of stool, although labeling the stool with high contrast agents replaces the use of laxatives and reduces the patient discomfort. This procedure introduces additional challenges for the diagnosis, such as poorly tagged stool, stool sticking to colonic walls, and heterogeneous stool (tagged stool mixed with air or untagged stool). Our study proposes a robust algorithm for heterogeneous stool removal to be employed as a preprocessing module for CAD systems in colonic cancer detection. Colonoscopy data are automatically cleansed of residual stool to enhance the polyp appearance for improved diagnosis. The algorithm uses expectation-maximization, quadratic regression, level sets and minimum variance. Results show stool removal accuracy on polyps which are partially or fully covered by stool. The results are robust on stool lining and large pools of heterogeneous and weakly-tagged stool. The automatic detection of colon polyps using our CAD system on cathartic-free data improves considerably with the addition of the automatic stool removal module from 74% to 86% true positive (TP) rate at 6.4 false positives (FP)/case.

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

    PubMed

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

    2014-12-01

    To prospectively evaluate the effect of listening to music and inhaling aroma oil on patients undergoing screening computed tomography colonography. 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. 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). 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. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. 3D Dose Verification Using Tomotherapy CT Detector Array

    SciTech Connect

    Sheng Ke; Jones, Ryan; Yang Wensha; Saraiya, Siddharth; Schneider, Bernard; Chen Quan; Sobering, Geoff; Olivera, Gustavo; Read, Paul

    2012-02-01

    Purpose: To evaluate a three-dimensional dose verification method based on the exit dose using the onboard detector of tomotherapy. Methods and Materials: The study included 347 treatment fractions from 24 patients, including 10 prostate, 5 head and neck (HN), and 9 spinal stereotactic body radiation therapy (SBRT) cases. Detector sonograms were retrieved and back-projected to calculate entrance fluence, which was then forward-projected on the CT images to calculate the verification dose, which was compared with ion chamber and film measurement in the QA plans and with the planning dose in patient plans. Results: Root mean square (RMS) errors of 2.0%, 2.2%, and 2.0% were observed comparing the dose verification (DV) and the ion chamber measured point dose in the phantom plans for HN, prostate, and spinal SBRT patients, respectively. When cumulative dose in the entire treatment is considered, for HN patients, the error of the mean dose to the planning target volume (PTV) varied from 1.47% to 5.62% with a RMS error of 3.55%. For prostate patients, the error of the mean dose to the prostate target volume varied from -5.11% to 3.29%, with a RMS error of 2.49%. The RMS error of maximum doses to the bladder and the rectum were 2.34% (-4.17% to 2.61%) and 2.64% (-4.54% to 3.94%), respectively. For the nine spinal SBRT patients, the RMS error of the minimum dose to the PTV was 2.43% (-5.39% to 2.48%). The RMS error of maximum dose to the spinal cord was 1.05% (-2.86% to 0.89%). Conclusions: An excellent agreement was observed between the measurement and the verification dose. In the patient treatments, the agreement in doses to the majority of PTVs and organs at risk is within 5% for the cumulative treatment course doses. The dosimetric error strongly depends on the error in multileaf collimator leaf opening time with a sensitivity correlating to the gantry rotation period.

  4. Test of 3D CT reconstructions by EM + TV algorithm from undersampled data

    SciTech Connect

    Evseev, Ivan; Ahmann, Francielle; Silva, Hamilton P. da

    2013-05-06

    Computerized tomography (CT) plays an important role in medical imaging for diagnosis and therapy. However, CT imaging is connected with ionization radiation exposure of patients. Therefore, the dose reduction is an essential issue in CT. In 2011, the Expectation Maximization and Total Variation Based Model for CT Reconstruction (EM+TV) was proposed. This method can reconstruct a better image using less CT projections in comparison with the usual filtered back projection (FBP) technique. Thus, it could significantly reduce the overall dose of radiation in CT. This work reports the results of an independent numerical simulation for cone beam CT geometry with alternative virtual phantoms. As in the original report, the 3D CT images of 128 Multiplication-Sign 128 Multiplication-Sign 128 virtual phantoms were reconstructed. It was not possible to implement phantoms with lager dimensions because of the slowness of code execution even by the CORE i7 CPU.

  5. 3D CT-Video Fusion for Image-Guided Bronchoscopy

    PubMed Central

    Higgins, William E.; Helferty, James P.; Lu, Kongkuo; Merritt, Scott A.; Rai, Lav; Yu, Kun-Chang

    2008-01-01

    Bronchoscopic biopsy of the central-chest lymph nodes is an important step for lung-cancer staging. Before bronchoscopy, the physician first visually assesses a patient’s three-dimensional (3D) computed tomography (CT) chest scan to identify suspect lymph-node sites. Next, during bronchoscopy, the physician guides the bronchoscope to each desired lymph-node site. Unfortunately, the physician has no link between the 3D CT image data and the live video stream provided during bronchoscopy. Thus, the physician must essentially perform biopsy blindly, and the skill levels between different physicians differ greatly. We describe an approach that enables synergistic fusion between the 3D CT data and the bronchoscopic video. Both the integrated planning and guidance system and the internal CT-video registration and fusion methods are described. Phantom, animal, and human studies illustrate the efficacy of the methods. PMID:18096365

  6. 3D CT-video fusion for image-guided bronchoscopy.

    PubMed

    Higgins, William E; Helferty, James P; Lu, Kongkuo; Merritt, Scott A; Rai, Lav; Yu, Kun-Chang

    2008-04-01

    Bronchoscopic biopsy of the central-chest lymph nodes is an important step for lung-cancer staging. Before bronchoscopy, the physician first visually assesses a patient's three-dimensional (3D) computed tomography (CT) chest scan to identify suspect lymph-node sites. Next, during bronchoscopy, the physician guides the bronchoscope to each desired lymph-node site. Unfortunately, the physician has no link between the 3D CT image data and the live video stream provided during bronchoscopy. Thus, the physician must essentially perform biopsy blindly, and the skill levels between different physicians differ greatly. We describe an approach that enables synergistic fusion between the 3D CT data and the bronchoscopic video. Both the integrated planning and guidance system and the internal CT-video registration and fusion methods are described. Phantom, animal, and human studies illustrate the efficacy of the methods.

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

    PubMed

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

    2014-05-01

    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. • FOBt is the most common mass screening test for colorectal cancer. • Few studies evaluate CT colonography after positive FOBt. • CTC is approximately 89 % sensitive for ≥6 mm adenomas/cancer in this setting. • Specificity is lower, at approximately 75 %, and more variable. • CT colonography is a good alternative when colonoscopy is undesirable.

  8. Repositioning accuracy of two different mask systems-3D revisited: Comparison using true 3D/3D matching with cone-beam CT

    SciTech Connect

    Boda-Heggemann, Judit . E-mail: judit.boda-heggemann@radonk.ma.uni-heidelberg.de; Walter, Cornelia; Rahn, Angelika; Wertz, Hansjoerg; Loeb, Iris; Lohr, Frank; Wenz, Frederik

    2006-12-01

    Purpose: The repositioning accuracy of mask-based fixation systems has been assessed with two-dimensional/two-dimensional or two-dimensional/three-dimensional (3D) matching. We analyzed the accuracy of commercially available head mask systems, using true 3D/3D matching, with X-ray volume imaging and cone-beam CT. Methods and Materials: Twenty-one patients receiving radiotherapy (intracranial/head-and-neck tumors) were evaluated (14 patients with rigid and 7 with thermoplastic masks). X-ray volume imaging was analyzed online and offline separately for the skull and neck regions. Translation/rotation errors of the target isocenter were analyzed. Four patients were treated to neck sites. For these patients, repositioning was aided by additional body tattoos. A separate analysis of the setup error on the basis of the registration of the cervical vertebra was performed. The residual error after correction and intrafractional motility were calculated. Results: The mean length of the displacement vector for rigid masks was 0.312 {+-} 0.152 cm (intracranial) and 0.586 {+-} 0.294 cm (neck). For the thermoplastic masks, the value was 0.472 {+-} 0.174 cm (intracranial) and 0.726 {+-} 0.445 cm (neck). Rigid masks with body tattoos had a displacement vector length in the neck region of 0.35 {+-} 0.197 cm. The intracranial residual error and intrafractional motility after X-ray volume imaging correction for rigid masks was 0.188 {+-} 0.074 cm, and was 0.134 {+-} 0.14 cm for thermoplastic masks. Conclusions: The results of our study have demonstrated that rigid masks have a high intracranial repositioning accuracy per se. Given the small residual error and intrafractional movement, thermoplastic masks may also be used for high-precision treatments when combined with cone-beam CT. The neck region repositioning accuracy was worse than the intracranial accuracy in both cases. However, body tattoos and image guidance improved the accuracy. Finally, the combination of both mask

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

    SciTech Connect

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

    2009-12-15

    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.

  10. Volumetric texture features from higher-order images for diagnosis of colon lesions via CT colonography

    PubMed Central

    Song, Bowen; Zhang, Guopeng; Lu, Hongbing; Wang, Huafeng; Zhu, Wei; Pickhardt, Perry J.

    2014-01-01

    Purpose Differentiation of colon lesions according to underlying pathology, e.g., neoplastic and non-neoplastic lesions, is of fundamental importance for patient management. Image intensity-based textural features have been recognized as useful biomarker for the differentiation task. In this paper, we introduce texture features from higher-order images, i.e., gradient and curvature images, beyond the intensity image, for that task. Methods Based on the Haralick texture analysis method, we introduce a virtual pathological model 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 a database consisting of 148 colon lesions, of which 35 are non-neoplastic lesions, using the support vector machine classifier and the merit of area under the curve (AUC) of the receiver operating characteristics. Results The AUC of classification was improved from 0.74 (using the image intensity alone) to 0.85 (by also considering the gradient and curvature images) in differentiating the neoplastic lesions from non-neoplastic ones, e.g., hyperplastic polyps from tubular adenomas, tubulovillous adenomas and adenocarcinomas. Conclusions The experimental results demonstrated that texture features from 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 colonography for colorectal cancer screening by not only detecting polyps but also classifying them for optimal polyp management for the best outcome in personalized medicine. PMID:24696313

  11. Multimodal 3D PET/CT system for bronchoscopic procedure planning

    NASA Astrophysics Data System (ADS)

    Cheirsilp, Ronnarit; Higgins, William E.

    2013-02-01

    Integrated positron emission tomography (PET) / computed-tomography (CT) scanners give 3D multimodal data sets of the chest. Such data sets offer the potential for more complete and specific identification of suspect lesions and lymph nodes for lung-cancer assessment. This in turn enables better planning of staging bronchoscopies. The richness of the data, however, makes the visualization and planning process difficult. We present an integrated multimodal 3D PET/CT system that enables efficient region identification and bronchoscopic procedure planning. The system first invokes a series of automated 3D image-processing methods that construct a 3D chest model. Next, the user interacts with a set of interactive multimodal graphical tools that facilitate procedure planning for specific regions of interest (ROIs): 1) an interactive region candidate list that enables efficient ROI viewing in all tools; 2) a virtual PET-CT bronchoscopy rendering with SUV quantitative visualization to give a "fly through" endoluminal view of prospective ROIs; 3) transverse, sagittal, coronal multi-planar reformatted (MPR) views of the raw CT, PET, and fused CT-PET data; and 4) interactive multimodal volume/surface rendering to give a 3D perspective of the anatomy and candidate ROIs. In addition the ROI selection process is driven by a semi-automatic multimodal method for region identification. In this way, the system provides both global and local information to facilitate more specific ROI identification and procedure planning. We present results to illustrate the system's function and performance.

  12. [Spiral computerized tomography with tridimensional reconstruction (spiral 3D CT) in the study of maxillofacial pathology].

    PubMed

    Mevio, E; Calabrò, P; Preda, L; Di Maggio, E M; Caprotti, A

    1995-12-01

    Three dimensional computer reconstruction of CT scans provide head and neck surgeons with an exciting interactive display of clinical anatomy. The 3D CT reconstruction of complex maxillo facial anatomic parts permits a more specific preoperative analysis and surgical planning. Its delineation of disease extension aids the surgeon in developing his own mental three-dimensional image of the regional morphology. Three-dimensional CT permits a clearer perception of the extent of fracture comminution and resulting displacement of fragments. In the case of maxillo-facial tumors, 3D images provide a very clear picture of the extent of erosion involving the adjacent critical organs. Three-dimensional imaging in first generation 3D scanners did have some limitations such as long reconstruction times and inadequate resolution. Subsequent generations, in particular the spiral 3D CT, have eliminated these drawbacks. Furthermore, costs are comparable with those of other computer reconstruction technology that might provide similar images. Representative cases demonstrating the use of 3D CT in maxillofacial surgery and its benefits in planning surgery are discussed.

  13. Patient specific respiratory motion modeling using a limited number of 3D lung CT images.

    PubMed

    Cui, Xueli; Gao, Xin; Xia, Wei; Liu, Yangchuan; Liang, Zhiyuan

    2014-01-01

    To build a patient specific respiratory motion model with a low dose, a novel method was proposed that uses a limited number of 3D lung CT volumes with an external respiratory signal. 4D lung CT volumes were acquired for patients with in vitro labeling on the upper abdominal surface. Meanwhile, 3D coordinates of in vitro labeling were measured as external respiratory signals. A sequential correspondence between the 4D lung CT and the external respiratory signal was built using the distance correlation method, and a 3D displacement for every registration control point in the CT volumes with respect to time can be obtained by the 4D lung CT deformable registration. A temporal fitting was performed for every registration control point displacements and an external respiratory signal in the anterior-posterior direction respectively to draw their fitting curves. Finally, a linear regression was used to fit the corresponding samples of the control point displacement fitting curves and the external respiratory signal fitting curve to finish the pulmonary respiration modeling. Compared to a B-spline-based method using the respiratory signal phase, the proposed method is highly advantageous as it offers comparable modeling accuracy and target modeling error (TME); while at the same time, the proposed method requires 70% less 3D lung CTs. When using a similar amount of 3D lung CT data, the mean of the proposed method's TME is smaller than the mean of the PCA (principle component analysis)-based methods' TMEs. The results indicate that the proposed method is successful in striking a balance between modeling accuracy and number of 3D lung CT volumes.

  14. Adapted morphing model for 3D volume reconstruction applied to abdominal CT images

    NASA Astrophysics Data System (ADS)

    Fadeev, Aleksey; Eltonsy, Nevine; Tourassi, Georgia; Martin, Robert; Elmaghraby, Adel

    2005-04-01

    The purpose of this study was to develop a 3D volume reconstruction model for volume rendering and apply this model to abdominal CT data. The model development includes two steps: (1) interpolation of given data for a complete 3D model, and (2) visualization. First, CT slices are interpolated using a special morphing algorithm. The main idea of this algorithm is to take a region from one CT slice and locate its most probable correspondence in the adjacent CT slice. The algorithm determines the transformation function of the region in between two adjacent CT slices and interpolates the data accordingly. The most probable correspondence of a region is obtained using correlation analysis between the given region and regions of the adjacent CT slice. By applying this technique recursively, taking progressively smaller subregions within a region, a high quality and accuracy interpolation is obtained. The main advantages of this morphing algorithm are 1) its applicability not only to parallel planes like CT slices but also to general configurations of planes in 3D space, and 2) its fully automated nature as it does not require control points to be specified by a user compared to most morphing techniques. Subsequently, to visualize data, a specialized volume rendering card (TeraRecon VolumePro 1000) was used. To represent data in 3D space, special software was developed to convert interpolated CT slices to 3D objects compatible with the VolumePro card. Visual comparison between the proposed model and linear interpolation clearly demonstrates the superiority of the proposed model.

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

    PubMed Central

    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

  16. Exploration of Analysis Methods for Diagnostic Imaging Tests: Problems with ROC AUC and Confidence Scores in CT Colonography

    PubMed Central

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

    2014-01-01

    Background 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. Methods 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. Results 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. Conclusions 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. PMID:25353643

  17. Non-laxative CT colonography with barium-based faecal tagging: is additional phosphate enema beneficial and well tolerated?

    PubMed

    Davis, W; Nisbet, P; Hare, C; Cooke, P; Taylor, S A

    2011-02-01

    The purpose of this study was to investigate the efficacy and tolerance of an additional phosphate enema prior to non-laxative CT colonography (CTC). 71 patients (mean age 80 years, 28 male, 43 female) underwent non-laxative CTC following 4 oral doses of diluted 2% w/w barium sulphate. Patients were invited to self-administer a phosphate enema 2 h before CTC. An experienced observer graded the volume of retained stool (1 (nil) to 4 (>75% bowel circumference coated)), retained fluid ((1 (nil) to 4 (>50% circumference obscured)), retained stool tagging quality (1 (untagged) to 5 (≥75% to 100%) tagged) and confidence a polyp ≥6 mm could be excluded (yes/no) for each of six colonic segments. Tolerance of the enema was assessed via questionnaire. Data were analysed between those using and not using the enema by Mann-Whitney and Fisher's exact test. 18/71 patients declined the enema. There was no reduction in residual stool volume with enema use compared with non-use either overall (mean score 2.6 vs 2.7, p = 0.76) or in the left colon (mean 2.3 vs 2.4, p = 0.47). Overall tagging quality was no different (mean score 4.4 vs 4.3, p = 0.43). There was significantly more retained left colonic fluid post enema (mean score 1.9 vs 1.1, p<0.0001), and diagnostic confidence in excluding polyps was significantly reduced (exclusion not possible in 35% segments vs 21% without enema, p = 0.006). Of 53 patients, 30 (56%) found the enema straightforward to use, but 4 (8%) found it unpleasant. Phosphate enema use prior to non-laxative CTC leads to greater retained fluid, reducing diagnostic confidence, and is not recommended.

  18. Detailed quantitative assessment of colonic morphology at CT colonography using novel software: a feasibility and reproducibility study.

    PubMed

    Weber, Charles N; Lev-Toaff, Anna S; Levine, Marc S; Sudarsky, Sandra; Guendel, Lutz; Geiger, Bernhard; Zafar, Hanna M

    2017-03-01

    The aim of this study was to evaluate feasibility and reproducibility of quantitative assessment of colonic morphology on CT colonography (CTC). CTC datasets from 60 patients with optimal colonic distension were assessed using prototype software. Metrics potentially associated with poor endoscopic performance were calculated for the total colon and each segment including: length, volume, tortuosity (number of high curvature points <90°), and compactness (volume of box containing centerline divided by centerline length). Sigmoid apex height relative to the lumbosacral junction was also measured. Datasets were quantified twice each, and intra-reader reliability was evaluated using concordance correlation coefficient and Bland-Altman plot. Complete quantitative datasets including the five proposed metrics were generated from 58 of 60 (97 %) CTC examinations. The sigmoid and transverse segments were the longest (55.9 and 51.4 cm), had the largest volumes (0.410 and 0.609 L), and were the most tortuous (3.39 and 2.75 high curvature points) and least compact (3347 and 3595 mm(2)), noting high inter-patient variability for all metrics. Mean height of the sigmoid apex was 6.7 cm, also with high inter-patient variability (SD 6.8 cm). Intra-reader reliability was high for total and segmental lengths and sigmoid apex height (CCC = 0.9991) with excellent repeatability coefficient (CR = 3.0-3.3). There was low percent variance of metrics dependent upon length (median 5 %). Detailed automated quantitative assessment of colonic morphology on routine CTC datasets is feasible and reproducible, requiring minimal reader interaction.

  19. Do prevalence expectations affect patterns of visual search and decision-making in interpreting CT colonography endoluminal videos?

    PubMed Central

    Phillips, Peter; Plumb, Andrew; Helbren, Emma; Halligan, Steve; Taylor, Stuart A; Gale, Alastair; Mallett, Susan

    2016-01-01

    Objective: To assess the effect of expected abnormality prevalence on visual search and decision-making in CT colonography (CTC). Methods: 13 radiologists interpreted endoluminal CTC fly-throughs of the same group of 10 patient cases, 3 times each. Abnormality prevalence was fixed (50%), but readers were told, before viewing each group, that prevalence was either 20%, 50% or 80% in the population from which cases were drawn. Infrared visual search recording was used. Readers indicated seeing a polyp by clicking a mouse. Multilevel modelling quantified the effect of expected prevalence on outcomes. Results: Differences between expected prevalence were not statistically significant for time to first pursuit of the polyp (median 0.5 s, each prevalence), pursuit rate when no polyp was on screen (median 2.7 s−1, each prevalence) or number of mouse clicks [mean 0.75/video (20% prevalence), 0.93 (50%), 0.97 (80%)]. There was weak evidence of increased tendency to look outside the central screen area at 80% prevalence and reduction in positive polyp identifications at 20% prevalence. Conclusion: This study did not find a large effect of prevalence information on most visual search metrics or polyp identification in CTC. Further research is required to quantify effects at lower prevalence and in relation to secondary outcome measures. Advances in knowledge: Prevalence effects in evaluating CTC have not previously been assessed. In this study, providing expected prevalence information did not have a large effect on diagnostic decisions or patterns of visual search. PMID:26903391

  20. Objective and Subjective Intra-patient Comparison of Iohexol versus Diatrizoate for Bowel Preparation Quality at CT Colonography

    PubMed Central

    Johnson, Brandon; Hinshaw, J. Louis; Robbins, Jessica B.; Pickhardt, Perry J.

    2017-01-01

    Objective To objectively and subjectively compare nonionic iohexol and ionic diatrizoate iodinated oral contrast as part of a cathartic bowel regimen within the same CT colonography (CTC) cohort, with otherwise identical preparations. Materials and Methods In our IRB-approved retrospective study, 46 asymptomatic adults (mean age, 59.4 years; 26M/20F) returning for follow-up CTC over a 9-month interval underwent the same bowel preparation with the exception of 75 ml iohexol 350 (Omnipaque) in place of 60 ml diatrizoate (Gastrografin). All other preparation components (bisacodyl, magnesium citrate, and 2% barium) remained constant. Objective volumetric analysis of residual colonic fluid volume and fluid attenuation was performed. Additionally, two radiologists experienced with CTC, blinded to the specific bowel preparation, scored each of 6 colonic segments for adherent residual solid stool using a previously validated 4-point scale (0 for no stool; 1–3 for increasing residual stool). Paired t-test was used for comparison of the cohorts. Results No clear clinically-meaningful difference was found between the two preparations on overall objective or subjective evaluation. Mean (±SD) residual fluid volume was 173±126 ml with the iohexol preparation and 130±79 ml with the diatrizoate prep (p=0.02). Mean total colonic stool score was 2.5 (0.42/segment) with iohexol and 2.3 (0.38/segment) with diatrizoate (p=0.69). Mean (±SD) fluid attenuation was higher with iohexol (849±270HU) compared with diatrizoate (732±168HU) (p=0.03). Conclusions Based on this direct intra-patient comparison, we found that oral iohexol is a suitable alternative to diatrizoate for fluid tagging as part of a cathartic bowel preparation at CTC. Because this nonionic tagging agent is more palatable, less expensive, and likely safer than ionic diatrizoate, our CTC program now utilizes iohexol as the standard recommended regimen. PMID:27010251

  1. CT colonography: optimisation, diagnostic performance and patient acceptability of reduced-laxative regimens using barium-based faecal tagging

    PubMed Central

    Slater, Andrew; Burling, David N.; Tam, Emily; Greenhalgh, Rebecca; Gartner, Louise; Scarth, Julia; Pearce, Robert; Bassett, Paul; Halligan, Steve

    2007-01-01

    To establish the optimum barium-based reduced-laxative tagging regimen prior to CT colonography (CTC). Ninety-five subjects underwent reduced-laxative (13 g senna/18 g magnesium citrate) CTC prior to same-day colonoscopy and were randomised to one of four tagging regimens using 20 ml 40%w/v barium sulphate: regimen A: four doses, B: three doses, C: three doses plus 220 ml 2.1% barium sulphate, or D: three doses plus 15 ml diatriazoate megluamine. Patient experience was assessed immediately after CTC and 1 week later. Two radiologists graded residual stool (1: none/scattered to 4: >50% circumference) and tagging efficacy for stool (1: untagged to 5: 100% tagged) and fluid (1: untagged, 2: layered, 3: tagged), noting the HU of tagged fluid. Preparation was good (76–94% segments graded 1), although best for regimen D (P = 0.02). Across all regimens, stool tagging quality was high (mean 3.7–4.5) and not significantly different among regimens. The HU of layered tagged fluid was higher for regimens C/D than A/B (P = 0.002). Detection of cancer (n = 2), polyps ≥6 mm (n = 21), and ≤5 mm (n = 72) was 100, 81 and 32% respectively, with only four false positives ≥6 mm. Reduced preparation was tolerated better than full endoscopic preparation by 61%. Reduced-laxative CTC with three doses of 20 ml 40% barium sulphate is as effective as more complex regimens, retaining adequate diagnostic accuracy. PMID:17404739

  2. Performance evaluation of multi-material electronic cleansing for ultra-low-dose dual-energy CT colonography

    NASA Astrophysics Data System (ADS)

    Tachibana, Rie; Kohlhase, Naja; Näppi, Janne J.; Hironaka, Toru; Ota, Junko; Ishida, Takayuki; Regge, Daniele; Yoshida, Hiroyuki

    2016-03-01

    Accurate electronic cleansing (EC) for CT colonography (CTC) enables the visualization of the entire colonic surface without residual materials. In this study, we evaluated the accuracy of a novel multi-material electronic cleansing (MUMA-EC) scheme for non-cathartic ultra-low-dose dual-energy CTC (DE-CTC). The MUMA-EC performs a wateriodine material decomposition of the DE-CTC images and calculates virtual monochromatic images at multiple energies, after which a random forest classifier is used to label the images into the regions of lumen air, soft tissue, fecal tagging, and two types of partial-volume boundaries based on image-based features. After the labeling, materials other than soft tissue are subtracted from the CTC images. For pilot evaluation, 384 volumes of interest (VOIs), which represented sources of subtraction artifacts observed in current EC schemes, were sampled from 32 ultra-low-dose DE-CTC scans. The voxels in the VOIs were labeled manually to serve as a reference standard. The metric for EC accuracy was the mean overlap ratio between the labels of the reference standard and the labels generated by the MUMA-EC, a dualenergy EC (DE-EC), and a single-energy EC (SE-EC) scheme. Statistically significant differences were observed between the performance of the MUMA/DE-EC and the SE-EC methods (p<0.001). Visual assessment confirmed that the MUMA-EC generated less subtraction artifacts than did DE-EC and SE-EC. Our MUMA-EC scheme yielded superior performance over conventional SE-EC scheme in identifying and minimizing subtraction artifacts on noncathartic ultra-low-dose DE-CTC images.

  3. Automated volumetric analysis for comparison of oral sulfate solution (SUPREP) with established cathartic agents at CT colonography

    PubMed Central

    Bannas, Peter; Bakke, Joshua; Patrick, James L.; Pickhardt, Perry J.

    2015-01-01

    Purpose To objectively compare residual colonic fluid volume and attenuation of oral sulfate solution (OSS) with four different established cathartic regimens using an automated volumetric software tool at CT colonography (CTC). Methods This HIPAA-compliant study had institutional review board approval. Volumetric analysis of residual contrast-tagged colonic fluid was performed on CTC studies in 263 adults (mean age, 60.1 years; 137M/126F) using an automated volumetric software tool. 23 patients receiving 177 ml OSS (SUPREP; single-bottle purgation) were compared with 60 patients each receiving 45 ml sodium phosphate (NaP), 90 ml NaP (2xNaP), 592 ml (two bottles) magnesium citrate (MgC), and 4000 ml polyethylene glycol (PEG). All patients received oral contrast cleansing after catharsis. Data were analyzed with unpaired t test with Welch correction and F test. Results The mean volume of residual colonic fluid was less with OSS (125±60 ml) than for established cathartic agents: 2xNaP (206±125 ml, (p<0.0001), MgC (184±125 ml, p<0.01), PEG (166±114 ml, p<0.05) and NaP (165±135 ml, p=0.067). Variance of volumes was also significantly lower for OSS (range, 28 – 251 ml) than for established agents (range, 4 – 853 ml) (all p<0.01). Mean fluid attenuation was higher with OSS (956±168 HU) than for established agents (all p<0.05): 2xNaP (455±191 HU), MgC (691±154 HU), NaP (779±127 HU), and PEG (843±193 HU). Conclusions Automated volumetry allows rapid objective assessment of bowel preparation quality at CTC. Purgation with the novel oral sulfate solution (SUPREP) consistently resulted in less residual colonic fluid and higher fluid attenuation compared with established cathartic regimens. PMID:24965898

  4. Mosaic decomposition method for detection and removal of inhomogeneously tagged regions in electronic cleansing for CT colonography

    NASA Astrophysics Data System (ADS)

    Cai, Wenli; Zalis, Micheal; Yoshida, Hiroyuki

    2008-03-01

    Electronic cleansing (EC) is a method that segments fecal material tagged by an X-ray-opaque oral contrast agent in CT colonography (CTC) images, and effectively removes the material for digitally cleansing the colon. In this study, we developed a novel EC method, called mosaic decomposition, for reduction of the artifacts due to incomplete cleansing of heterogeneously tagged fecal material in reduced- or non-cathartic fecal-tagging CTC examinations. In our approach, a segmented colonic lumen, including the tagged regions, was first partitioned into a set of local homogeneous regions by application of a watershed transform to the gradient of the CTC images. Then, each of the local homogeneous regions was classified into five different material classes, including air, soft tissue, tagged feces, air bubbles, and foodstuff, based on texture features of the tile. A single index, called a soft-tissue index, is formulated for differentiation of these materials from the submerged solid soft-tissue structures such as polyps and folds. Here, a larger value of the index indicates a higher likelihood of soft tissue. Then, EC is performed by first initializing the level-set front with the classified tagged regions, and the front is evolved by use of a speed function that was designed, based on the soft-tissue index, to reserve the submerged soft-tissue structures while suppressing the air bubbles and foodstuff. Visual assessment and application of our computer-aided detection (CAD) of polyps showed that the use of our new EC method substantially improved the detection performance of CAD, indicating the effectiveness of our EC method in reducing incomplete cleansing artifacts.

  5. 3D Printing of CT Dataset: Validation of an Open Source and Consumer-Available Workflow.

    PubMed

    Bortolotto, Chandra; Eshja, Esmeralda; Peroni, Caterina; Orlandi, Matteo A; Bizzotto, Nicola; Poggi, Paolo

    2016-02-01

    The broad availability of cheap three-dimensional (3D) printing equipment has raised the need for a thorough analysis on its effects on clinical accuracy. Our aim is to determine whether the accuracy of 3D printing process is affected by the use of a low-budget workflow based on open source software and consumer's commercially available 3D printers. A group of test objects was scanned with a 64-slice computed tomography (CT) in order to build their 3D copies. CT datasets were elaborated using a software chain based on three free and open source software. Objects were printed out with a commercially available 3D printer. Both the 3D copies and the test objects were measured using a digital professional caliper. Overall, the objects' mean absolute difference between test objects and 3D copies is 0.23 mm and the mean relative difference amounts to 0.55 %. Our results demonstrate that the accuracy of 3D printing process remains high despite the use of a low-budget workflow.

  6. A statistical description of 3D lung texture from CT data

    NASA Astrophysics Data System (ADS)

    Chaisaowong, Kraisorn; Paul, Andreas

    2015-03-01

    A method was described to create a statistical description of 3D lung texture from CT data. The second order statistics, i.e. the gray level co-occurrence matrix (GLCM), has been applied to characterize texture of lung by defining the joint probability distribution of pixel pairs. The required GLCM was extended to three-dimensional image regions to deal with CT volume data. For a fine-scale lung segmentation, both the 3D GLCM of lung and thorax without lung are required. Once the co-occurrence densities are measured, the 3D models of the joint probability density function for each describing direction of involving voxel pairs and for each class (lung or thorax) are estimated using mixture of Gaussians through the expectation-maximization algorithm. This leads to a feature space that describes the 3D lung texture.

  7. The safety of same-day CT colonography following incomplete colonoscopy with polypectomy

    PubMed Central

    Avalos, Danny; Huynh, Huan; Jimenez-Cantisano, Brenda; Padron, Mariann; Pimentel, Ronnie; Erim, Tolga; Schneider, Alison; Ukleja, Andrew; Parlade, Albert; Castro, Fernando

    2015-01-01

    Background Concerns about the risk of bowel perforation for same-day computed tomography colonography (CTC) following an incomplete colonoscopy with polypectomy may lead to unnecessarily postponing the CTC. Objective The objective of this article is to describe the complications including colon perforations associated with same-day CTC in a cohort who had polypectomies but an incomplete colonoscopy. Design We conducted a retrospective study. Setting Our study took place in a single, tertiary referral center. Patients We studied consecutive patients who had CTC the same day as an incomplete colonoscopy with polypectomy. Interventions Interventions included optical colonoscopy (OC), endoscopic polypectomies, and same-day CTC. Main outcome measurements: Our main outcome measurements included perforation rate with long-term follow-up. Results A total of 3% of patients undergoing colonoscopy from January 2008 to December 2012 had same-day CTC following incomplete OC, and 72 polypectomies were performed in 34 (or 17%) of these patients. Incomplete colonoscopies were due to colon tortuosity and looping (25), severe angulations (five), colon mass (two), colon stenosis (one), bradycardia (one). Fifty-three percent of the OCs were screening for colon neoplasia, 29% diagnostic and 18% were surveillance of colon polyps. Most polyps were ≤ 5 mm, and found in the left colon. There were no reported complications or perforations associated with same-day CTCs during short- and long-term follow-up. Limitations Limitations of our analysis included retrospective single-center design, small number of patients for the occurrence, referral to same-day CTC was not standardized, inability to establish safety of CTC for specific scenarios such as after complex polypectomies, strictures, or advanced IBD. Conclusions Radiologists’ apprehension to perform a CTC the same day as an incomplete colonoscopy following polypectomies because of perceived risk of perforation may be unfounded

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

    PubMed

    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 <.001). The effective radiation dose, calculated with a Monte Carlo simulation, was 1.4-10.0 mSv. Detection of small polyps (<5 mm) with multi-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

  9. High-performance computer aided detection system for polyp detection in CT colonography with fluid and fecal tagging

    NASA Astrophysics Data System (ADS)

    Liu, Jiamin; Wang, Shijun; Kabadi, Suraj; Summers, Ronald M.

    2009-02-01

    CT colonography (CTC) is a feasible and minimally invasive method for the detection of colorectal polyps and cancer screening. Computer-aided detection (CAD) of polyps has improved consistency and sensitivity of virtual colonoscopy interpretation and reduced interpretation burden. A CAD system typically consists of four stages: (1) image preprocessing including colon segmentation; (2) initial detection generation; (3) feature selection; and (4) detection classification. In our experience, three existing problems limit the performance of our current CAD system. First, highdensity orally administered contrast agents in fecal-tagging CTC have scatter effects on neighboring tissues. The scattering manifests itself as an artificial elevation in the observed CT attenuation values of the neighboring tissues. This pseudo-enhancement phenomenon presents a problem for the application of computer-aided polyp detection, especially when polyps are submerged in the contrast agents. Second, general kernel approach for surface curvature computation in the second stage of our CAD system could yield erroneous results for thin structures such as small (6-9 mm) polyps and for touching structures such as polyps that lie on haustral folds. Those erroneous curvatures will reduce the sensitivity of polyp detection. The third problem is that more than 150 features are selected from each polyp candidate in the third stage of our CAD system. These high dimensional features make it difficult to learn a good decision boundary for detection classification and reduce the accuracy of predictions. Therefore, an improved CAD system for polyp detection in CTC data is proposed by introducing three new techniques. First, a scale-based scatter correction algorithm is applied to reduce pseudo-enhancement effects in the image pre-processing stage. Second, a cubic spline interpolation method is utilized to accurately estimate curvatures for initial detection generation. Third, a new dimensionality

  10. High resolution 3D dosimetry for microbeam radiation therapy using optical CT

    NASA Astrophysics Data System (ADS)

    McErlean, C.; Bräuer-Krisch, E.; Adamovics, J.; Leach, M. O.; Doran, S. J.

    2015-01-01

    Optical Computed Tomography (CT) is a promising technique for dosimetry of Microbeam Radiation Therapy (MRT), providing high resolution 3D dose maps. Here different MRT irradiation geometries are visualised showing the potential of Optical CT as a tool for future MRT trials. The Peak-to-Valley dose ratio (PVDR) is calculated to be 7 at a depth of 3mm in the radiochromic dosimeter PRESAGE®. This is significantly lower than predicted values and possible reasons for this are discussed.

  11. Comparison of femoral neck BMD evaluation obtained using Lunar DXA and QCT with asynchronous calibration from CT colonography.

    PubMed

    Pickhardt, Perry J; Bodeen, Gabriel; Brett, Alan; Brown, J Keenan; Binkley, Neil

    2015-01-01

    For patients undergoing screening computed tomography colonography (CTC), an opportunity exists for bone mineral density (BMD) screening without additional radiation exposure using quantitative computed tomography (QCT). This study investigated the use of dual-energy X-ray absorptiometry (DXA)-equivalent QCT Computed Tomography X-Ray Absorptiometry (CTXA) analysis at the hip obtained using CTC examinations using a retrospective asynchronous calibration of patient scans. A cohort of 33 women, age 61.3 (10.6) yr (mean [standard deviation]), had routine CTC using various GE LightSpeed CT scanner models followed after 0-9 mo by a DXA hip BMD examination using a GE Lunar Prodigy machine. Areal bone mineral density (aBMD) and T-scores of the proximal femur were measured from either prone or supine CTC examinations using Mindways QCT Pro software following standard workflow except that the CT scanners were asynchronously calibrated by phantoms scanned retrospectively of the CTC examination without the subject present. CTXA and DXA aBMD were highly correlated (R2=0.907) with a linear relationship of DXA_BMD=1.297*CTXA_BMD+0.048. The standard error of estimate (SEE) on the linear fit was 0.053 g/cm2. CTXA and DXA T-scores showed a linear relationship of DXA_T-score=1.034*CTXA_T-score+0.3 and an SEE of 0.379 T-scores. CTXA and DXA aBMD and T-score measurements showed good correlation despite asynchronous scan acquisition and retrospective QCT calibration. The SEE of 0.053 g/cm2 is on par with the literature comparing Hologic and Lunar DXA devices. The observed relationship between CTXA and Lunar DXA aBMD matches predictions from published cross-calibrations relating CTXA to DXA aBMD measurement. Thus, opportunistic use of CTXA T-scores obtained at the time of CTC could enhance osteoporosis screening.

  12. Method of Individual Adjustment for 3D CT Analysis: Linear Measurement

    PubMed Central

    Choi, Dong Hun; Lee, Jeong Woo; Yang, Jung Dug; Chung, Ho Yun; Cho, Byung Chae

    2016-01-01

    Introduction. We aim to regularize measurement values in three-dimensional (3D) computed tomography (CT) reconstructed images for higher-precision 3D analysis, focusing on length-based 3D cephalometric examinations. Methods. We measure the linear distances between points on different skull models using Vernier calipers (real values). We use 10 differently tilted CT scans for 3D CT reconstruction of the models and measure the same linear distances from the picture archiving and communication system (PACS). In both cases, each measurement is performed three times by three doctors, yielding nine measurements. The real values are compared with the PACS values. Each PACS measurement is revised based on the display field of view (DFOV) values and compared with the real values. Results. The real values and the PACS measurement changes according to tilt value have no significant correlations (p > 0.05). However, significant correlations appear between the real values and DFOV-adjusted PACS measurements (p < 0.001). Hence, we obtain a correlation expression that can yield real physical values from PACS measurements. The DFOV value intervals for various age groups are also verified. Conclusion. Precise confirmation of individual preoperative length and precise analysis of postoperative improvements through 3D analysis is possible, which is helpful for facial-bone-surgery symmetry correction. PMID:28070517

  13. Method of Individual Adjustment for 3D CT Analysis: Linear Measurement.

    PubMed

    Kim, Dong Kyu; Choi, Dong Hun; Lee, Jeong Woo; Yang, Jung Dug; Chung, Ho Yun; Cho, Byung Chae; Choi, Kang Young

    2016-01-01

    Introduction. We aim to regularize measurement values in three-dimensional (3D) computed tomography (CT) reconstructed images for higher-precision 3D analysis, focusing on length-based 3D cephalometric examinations. Methods. We measure the linear distances between points on different skull models using Vernier calipers (real values). We use 10 differently tilted CT scans for 3D CT reconstruction of the models and measure the same linear distances from the picture archiving and communication system (PACS). In both cases, each measurement is performed three times by three doctors, yielding nine measurements. The real values are compared with the PACS values. Each PACS measurement is revised based on the display field of view (DFOV) values and compared with the real values. Results. The real values and the PACS measurement changes according to tilt value have no significant correlations (p > 0.05). However, significant correlations appear between the real values and DFOV-adjusted PACS measurements (p < 0.001). Hence, we obtain a correlation expression that can yield real physical values from PACS measurements. The DFOV value intervals for various age groups are also verified. Conclusion. Precise confirmation of individual preoperative length and precise analysis of postoperative improvements through 3D analysis is possible, which is helpful for facial-bone-surgery symmetry correction.

  14. Association between condylar asymmetry and temporo- mandibular disorders using 3D-CT

    PubMed Central

    Yáñez-Vico, Rosa M.; Iglesias-Linares, Alejandro; Torres-Lagares, Daniel; Solano-Reina, Enrique

    2012-01-01

    Objectives: Using reconstructed three-dimensional computed tomography (3D-CT) models, the purpose of this study was to analyze and compare mandibular condyle morphology in patients with and without temporomandibular disorder (TMD). Study Design: Thirty-two patients were divided into two groups: the first comprised those with TMD (n=18), and the second those who did not have TMD (n=14). A CT of each patient was obtained and reconstructed as a 3D model. The 64 resulting 3D condylar models were evaluated for possible TMD-associated length, width and height asymmetries of the condylar process. Descriptive statistics were used to assess the results and student’s t tests applied to compare the two groups. Results: Statistically significant (p<0.05) vertical, mediolateral and sagittal asymmetries of the condylar process were observed between TMD and non-TMD groups. TMD patients showed less condylar height (p<0.05) in comparison with their asymptomatic counterparts. Conclusions: Using 3D-CT, it was shown that condylar width, height and length asymmetries were a common feature of TMD. Key words:Condilar asymmetry, 3D-computed tomography, X-ray diagnosis , maxillofacial surgery, orthodontics. PMID:22322511

  15. Preoperative dual-phase 3D CT angiography assessment of the right hepatic artery before gastrectomy.

    PubMed

    Yamashita, Keishi; Sakuramoto, Shinichi; Mieno, Hiroaki; Shibata, Tomotaka; Nemoto, Masayuki; Katada, Natsuya; Kikuchi, Shiro; Watanabe, Masahiko

    2014-10-01

    In the current study, we evaluated the efficacy of dual-phase three-dimensional (3D) CT angiography (CTA) in the assessment of the vascular anatomy, especially the right hepatic artery (RHA), before gastrectomy. The study initially included 714 consecutive patients being treated for gastric cancer. A dual-phase contrast-enhanced CT scan using 32-multi detector-row CT was performed for all patients. Among the 714 patients, 3D CTA clearly identified anomalies with the RHA arising from the superior mesenteric artery (SMA) in 49 cases (6.9 %). In Michels' classification type IX, the common hepatic artery (CHA) originates only from the SMA. Such cases exhibit defective anatomy for the CHA in conjunction with the celiac-splenic artery system, resulting in direct exposure of the portal vein beneath the #8a lymph node station, which was retrospectively confirmed by video in laparoscopic gastrectomy cases. Fused images of both 3D angiography and venography were obtained, and could have predicted the risk preoperatively, and the surgical finding confirmed its usefulness. Preoperative evaluations using 3D CTA can provide more accurate information about the vessel anatomy. The fused images from 3D CTA have the potential to reduce the intraoperative risks for injuries to critical vessel, such as the portal vein, during gastrectomy.

  16. Evaluation of accuracy of 3D reconstruction images using multi-detector CT and cone-beam CT

    PubMed Central

    Kim, Mija; YI, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun; Choi, Soon-Chul

    2012-01-01

    Purpose This study was performed to determine the accuracy of linear measurements on three-dimensional (3D) images using multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). Materials and Methods MDCT and CBCT were performed using 24 dry skulls. Twenty-one measurements were taken on the dry skulls using digital caliper. Both types of CT data were imported into OnDemand software and identification of landmarks on the 3D surface rendering images and calculation of linear measurements were performed. Reproducibility of the measurements was assessed using repeated measures ANOVA and ICC, and the measurements were statistically compared using a Student t-test. Results All assessments under the direct measurement and image-based measurements on the 3D CT surface rendering images using MDCT and CBCT showed no statistically difference under the ICC examination. The measurements showed no differences between the direct measurements of dry skull and the image-based measurements on the 3D CT surface rendering images (P>.05). Conclusion Three-dimensional reconstructed surface rendering images using MDCT and CBCT would be appropriate for 3D measurements. PMID:22474645

  17. Application of 3D X-ray CT data sets to finite element analysis

    SciTech Connect

    Bossart, P.L.; Martz, H.E.; Brand, H.R.; Hollerbach, K.

    1995-08-31

    Finite Element Modeling (FEM) is becoming more important as industry drives toward concurrent engineering. A fundamental hindrance to fully exploiting the power of FEM is the human effort required to acquire complex part geometry, particularly as-built geometry, as a FEM mesh. Many Quantitative Non Destructive Evaluation (QNDE) techniques that produce three-dimensional (3D) data sets provide a substantial reduction in the effort required to apply FEM to as-built parts. This paper describes progress at LLNL on the application of 3D X-ray computed tomography (CT) data sets to more rapidly produce high-quality FEM meshes of complex, as-built geometries. Issues related to the volume segmentation of the 3D CT data as well as the use of this segmented data to tailor generic hexahedral FEM meshes to part specific geometries are discussed. The application of these techniques to FEM analysis in the medical field is reported here.

  18. AN AUTOMATIC 3D CT/PET SEGMENTATION FRAMEWORK FOR BONE MARROW PROLIFERATION ASSESSMENT.

    PubMed

    Nguyen, Chuong; Havlicek, Joseph; Duong, Quyen; Vesely, Sara; Gress, Ronald; Lindenberg, Liza; Choyke, Peter; Chakrabarty, Jennifer Holter; Williams, Kirsten

    2016-09-01

    Clinical assessment of bone marrow is limited by an inability to evaluate the marrow space comprehensively and dynamically and there is no current method for automatically assessing hematopoietic activity within the medullary space. Evaluating the hematopoietic space in its entirety could be applicable in blood disorders, malignancies, infections, and medication toxicity. In this paper, we introduce a CT/PET 3D automatic framework for measurement of the hematopoietic compartment proliferation within osseous sites. We first perform a full-body bone structure segmentation using 3D graph-cut on the CT volume. The vertebrae are segmented by detecting the discs between adjacent vertebrae. Finally, we register the bone marrow CT volume with its corresponding PET volume and capture the spinal bone marrow volume. The proposed framework was tested on 17 patients, achieving an average accuracy of 86.37% and a worst case accuracy of 82.3% in automatically extracting the aggregate volume of the spinal marrow cavities.

  19. Microstructure analysis of the secondary pulmonary lobules by 3D synchrotron radiation CT

    NASA Astrophysics Data System (ADS)

    Fukuoka, Y.; Kawata, Y.; Niki, N.; Umetani, K.; Nakano, Y.; Ohmatsu, H.; Moriyama, N.; Itoh, H.

    2014-03-01

    Recognition of abnormalities related to the lobular anatomy has become increasingly important in the diagnosis and differential diagnosis of lung abnormalities at clinical routines of CT examinations. This paper aims a 3-D microstructural analysis of the pulmonary acinus with isotropic spatial resolution in the range of several micrometers by using micro CT. Previously, we demonstrated the ability of synchrotron radiation micro CT (SRμCT) using offset scan mode in microstructural analysis of the whole part of the secondary pulmonary lobule. In this paper, we present a semiautomatic method to segment the acinar and subacinar airspaces from the secondary pulmonary lobule and to track small vessels running inside alveolar walls in human acinus imaged by the SRμCT. The method beains with and segmentation of the tissues such as pleural surface, interlobular septa, alveola wall, or vessel using a threshold technique and 3-D connected component analysis. 3-D air space are then conustructed separated by tissues and represented branching patterns of airways and airspaces distal to the terminal bronchiole. A graph-partitioning approach isolated acini whose stems are interactively defined as the terminal bronchiole in the secondary pulmonary lobule. Finally, we performed vessel tracking using a non-linear sate space which captures both smoothness of the trajectories and intensity coherence along vessel orientations. Results demonstrate that the proposed method can extract several acinar airspaces from the 3-D SRμCT image of secondary pulmonary lobule and that the extracted acinar airspace enable an accurate quantitative description of the anatomy of the human acinus for interpretation of the basic unit of pulmonary structure and function.

  20. Calculation of strain images of a breast-mimicking phantom from 3D CT image data.

    PubMed

    Kim, Jae G; Aowlad Hossain, A B M; Shin, Jong H; Lee, Soo Y

    2012-09-01

    Elastography is a medical imaging modality to visualize the elasticity of soft tissues. Ultrasound and MRI have been exclusively used for elastography of soft tissues since they can sensitize the tissues' minute displacements of an order of μm. It is known that ultrasound and MRI elastography show cancerous tissues with much higher contrast than conventional ultrasound and MRI. To evaluate possibility of combining elastography with x-ray imaging, we have calculated strain images of a breast-mimicking phantom from its 3D CT image data. We first simulated the x-ray elastography using a FEM model which incorporated both the elasticity and x-ray attenuation behaviors of breast tissues. After validating the x-ray elastography scheme by simulation, we made a breast-mimicking phantom that contained a hard inclusion against soft background. With a micro-CT, we took 3D images of the phantom twice, changing the compressing force to the phantom. From the two 3D phantom images taken with two different compression ratios, we calculated the displacement vector maps that represented the compression-induced pixel displacements. In calculating the displacement vectors, we tracked the movements of image feature patterns from the less-compressed-phantom images to the more-compressed-phantom images using the 3D image correlation technique. We obtained strain images of the phantom by differentiating the displacement vector maps. The FEM simulation has shown that x-ray strain imaging is possible by tracking image feature patterns in the 3D CT images of the breast-mimicking phantom. The experimental displacement and strain images of a breast-mimicking phantom, obtained from the 3D micro-CT images taken with 0%-3% compression ratios, show behaviors similar to the FEM simulation results. The contrast and noise performance of the strain images improves as the phantom compression ratio increases. We have experimentally shown that we can improve x-ray strain image quality by applying 3D

  1. TBIdoc: 3D content-based CT image retrieval system for traumatic brain injury

    NASA Astrophysics Data System (ADS)

    Li, Shimiao; Gong, Tianxia; Wang, Jie; Liu, Ruizhe; Tan, Chew Lim; Leong, Tze Yun; Pang, Boon Chuan; Lim, C. C. Tchoyoson; Lee, Cheng Kiang; Tian, Qi; Zhang, Zhuo

    2010-03-01

    Traumatic brain injury (TBI) is a major cause of death and disability. Computed Tomography (CT) scan is widely used in the diagnosis of TBI. Nowadays, large amount of TBI CT data is stacked in the hospital radiology department. Such data and the associated patient information contain valuable information for clinical diagnosis and outcome prediction. However, current hospital database system does not provide an efficient and intuitive tool for doctors to search out cases relevant to the current study case. In this paper, we present the TBIdoc system: a content-based image retrieval (CBIR) system which works on the TBI CT images. In this web-based system, user can query by uploading CT image slices from one study, retrieval result is a list of TBI cases ranked according to their 3D visual similarity to the query case. Specifically, cases of TBI CT images often present diffuse or focal lesions. In TBIdoc system, these pathological image features are represented as bin-based binary feature vectors. We use the Jaccard-Needham measure as the similarity measurement. Based on these, we propose a 3D similarity measure for computing the similarity score between two series of CT slices. nDCG is used to evaluate the system performance, which shows the system produces satisfactory retrieval results. The system is expected to improve the current hospital data management in TBI and to give better support for the clinical decision-making process. It may also contribute to the computer-aided education in TBI.

  2. Thoracic cavity definition for 3D PET/CT analysis and visualization.

    PubMed

    Cheirsilp, Ronnarit; Bascom, Rebecca; Allen, Thomas W; Higgins, William E

    2015-07-01

    X-ray computed tomography (CT) and positron emission tomography (PET) serve as the standard imaging modalities for lung-cancer management. CT gives anatomical details on diagnostic regions of interest (ROIs), while PET gives highly specific functional information. During the lung-cancer management process, a patient receives a co-registered whole-body PET/CT scan pair and a dedicated high-resolution chest CT scan. With these data, multimodal PET/CT ROI information can be gleaned to facilitate disease management. Effective image segmentation of the thoracic cavity, however, is needed to focus attention on the central chest. We present an automatic method for thoracic cavity segmentation from 3D CT scans. We then demonstrate how the method facilitates 3D ROI localization and visualization in patient multimodal imaging studies. Our segmentation method draws upon digital topological and morphological operations, active-contour analysis, and key organ landmarks. Using a large patient database, the method showed high agreement to ground-truth regions, with a mean coverage=99.2% and leakage=0.52%. Furthermore, it enabled extremely fast computation. For PET/CT lesion analysis, the segmentation method reduced ROI search space by 97.7% for a whole-body scan, or nearly 3 times greater than that achieved by a lung mask. Despite this reduction, we achieved 100% true-positive ROI detection, while also reducing the false-positive (FP) detection rate by >5 times over that achieved with a lung mask. Finally, the method greatly improved PET/CT visualization by eliminating false PET-avid obscurations arising from the heart, bones, and liver. In particular, PET MIP views and fused PET/CT renderings depicted unprecedented clarity of the lesions and neighboring anatomical structures truly relevant to lung-cancer assessment.

  3. Thoracic Cavity Definition for 3D PET/CT Analysis and Visualization

    PubMed Central

    Cheirsilp, Ronnarit; Bascom, Rebecca; Allen, Thomas W.; Higgins, William E.

    2015-01-01

    X-ray computed tomography (CT) and positron emission tomography (PET) serve as the standard imaging modalities for lung-cancer management. CT gives anatomical detail on diagnostic regions of interest (ROIs), while PET gives highly specific functional information. During the lung-cancer management process, a patient receives a co-registered whole-body PET/CT scan pair and a dedicated high-resolution chest CT scan. With these data, multimodal PET/CT ROI information can be gleaned to facilitate disease management. Effective image segmentation of the thoracic cavity, however, is needed to focus attention on the central chest. We present an automatic method for thoracic cavity segmentation from 3D CT scans. We then demonstrate how the method facilitates 3D ROI localization and visualization in patient multimodal imaging studies. Our segmentation method draws upon digital topological and morphological operations, active-contour analysis, and key organ landmarks. Using a large patient database, the method showed high agreement to ground-truth regions, with a mean coverage = 99.2% and leakage = 0.52%. Furthermore, it enabled extremely fast computation. For PET/CT lesion analysis, the segmentation method reduced ROI search space by 97.7% for a whole-body scan, or nearly 3 times greater than that achieved by a lung mask. Despite this reduction, we achieved 100% true-positive ROI detection, while also reducing the false-positive (FP) detection rate by >5 times over that achieved with a lung mask. Finally, the method greatly improved PET/CT visualization by eliminating false PET-avid obscurations arising from the heart, bones, and liver. In particular, PET MIP views and fused PET/CT renderings depicted unprecedented clarity of the lesions and neighboring anatomical structures truly relevant to lung-cancer assessment. PMID:25957746

  4. 3D printing based on cardiac CT assists anatomic visualization prior to transcatheter aortic valve replacement.

    PubMed

    Ripley, Beth; Kelil, Tatiana; Cheezum, Michael K; Goncalves, Alexandra; Di Carli, Marcelo F; Rybicki, Frank J; Steigner, Mike; Mitsouras, Dimitrios; Blankstein, Ron

    2016-01-01

    3D printing is a promising technique that may have applications in medicine, and there is expanding interest in the use of patient-specific 3D models to guide surgical interventions. To determine the feasibility of using cardiac CT to print individual models of the aortic root complex for transcatheter aortic valve replacement (TAVR) planning as well as to determine the ability to predict paravalvular aortic regurgitation (PAR). This retrospective study included 16 patients (9 with PAR identified on blinded interpretation of post-procedure trans-thoracic echocardiography and 7 age, sex, and valve size-matched controls with no PAR). 3D printed models of the aortic root were created from pre-TAVR cardiac computed tomography data. These models were fitted with printed valves and predictions regarding post-implant PAR were made using a light transmission test. Aortic root 3D models were highly accurate, with excellent agreement between annulus measurements made on 3D models and those made on corresponding 2D data (mean difference of -0.34 mm, 95% limits of agreement: ± 1.3 mm). The 3D printed valve models were within 0.1 mm of their designed dimensions. Examination of the fit of valves within patient-specific aortic root models correctly predicted PAR in 6 of 9 patients (6 true positive, 3 false negative) and absence of PAR in 5 of 7 patients (5 true negative, 2 false positive). Pre-TAVR 3D-printing based on cardiac CT provides a unique patient-specific method to assess the physical interplay of the aortic root and implanted valves. With additional optimization, 3D models may complement traditional techniques used for predicting which patients are more likely to develop PAR. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  5. Automated volumetric analysis for comparison of oral sulfate solution (SUPREP) with established cathartic agents at CT colonography.

    PubMed

    Bannas, Peter; Bakke, Joshua; Patrick, James L; Pickhardt, Perry J

    2015-01-01

    To objectively compare residual colonic fluid volume and attenuation of oral sulfate solution (OSS) with four different established cathartic regimens using an automated volumetric software tool at CT colonography (CTC). This HIPAA-compliant study had institutional review board approval. Volumetric analysis of residual contrast-tagged colonic fluid was performed on CTC studies in 263 adults (mean age 60.1 years; 137M/126F) using an automated volumetric software tool. Twenty-three patients receiving 177 mL OSS (SUPREP; single-bottle purgation) were compared with 60 patients each receiving 45 mL sodium phosphate (NaP), 90 mL NaP (2× NaP), 592 mL (two bottles) magnesium citrate (MgC), and 4,000 mL polyethylene glycol (PEG). All patients received oral contrast cleansing after catharsis. Data were analyzed with unpaired t test with Welch correction and F test. The mean volume of residual colonic fluid was less with OSS (125 ± 60 mL) than for established cathartic agents: 2× NaP (206 ± 125 mL, P < 0.0001), MgC (184 ± 125 mL, P < 0.01), PEG (166 ± 114 mL, P < 0.05), and NaP (165 ± 135 mL, P = 0.067). Variance of volumes was also significantly lower for OSS (range 28-251 mL) than for established agents (range 4-853 mL) (all P < 0.01). Mean fluid attenuation was higher with OSS (956 ± 168 HU) than for established agents (all P < 0.05): 2× NaP (455 ± 191 HU), MgC (691 ± 154 HU), NaP (779 ± 127 HU), and PEG (843 ± 193 HU). Automated volumetry allows rapid objective assessment of bowel preparation quality at CTC. Purgation with the novel oral sulfate solution (SUPREP) consistently resulted in less residual colonic fluid and higher fluid attenuation compared with established cathartic regimens.

  6. Inter-plane artifact suppression in tomosynthesis using 3D CT image data

    PubMed Central

    2011-01-01

    Background Despite its superb lateral resolution, flat-panel-detector (FPD) based tomosynthesis suffers from low contrast and inter-plane artifacts caused by incomplete cancellation of the projection components stemming from outside the focal plane. The incomplete cancellation of the projection components, mostly due to the limited scan angle in the conventional tomosynthesis scan geometry, often makes the image contrast too low to differentiate the malignant tissues from the background tissues with confidence. Methods In this paper, we propose a new method to suppress the inter-plane artifacts in FPD-based tomosynthesis. If 3D whole volume CT images are available before the tomosynthesis scan, the CT image data can be incorporated into the tomosynthesis image reconstruction to suppress the inter-plane artifacts, hence, improving the image contrast. In the proposed technique, the projection components stemming from outside the region-of-interest (ROI) are subtracted from the measured tomosynthesis projection data to suppress the inter-plane artifacts. The projection components stemming from outside the ROI are calculated from the 3D whole volume CT images which usually have lower lateral resolution than the tomosynthesis images. The tomosynthesis images are reconstructed from the subtracted projection data which account for the x-ray attenuation through the ROI. After verifying the proposed method by simulation, we have performed both CT scan and tomosynthesis scan on a phantom and a sacrificed rat using a FPD-based micro-CT. Results We have measured contrast-to-noise ratio (CNR) from the tomosynthesis images which is an indicator of the residual inter-plane artifacts on the focal-plane image. In both cases of the simulation and experimental imaging studies of the contrast evaluating phantom, CNRs have been significantly improved by the proposed method. In the rat imaging also, we have observed better visual contrast from the tomosynthesis images reconstructed by

  7. Inter-plane artifact suppression in tomosynthesis using 3D CT image data.

    PubMed

    Kim, Jae G; Jin, Seung O; Cho, Min H; Lee, Soo Y

    2011-12-10

    Despite its superb lateral resolution, flat-panel-detector (FPD) based tomosynthesis suffers from low contrast and inter-plane artifacts caused by incomplete cancellation of the projection components stemming from outside the focal plane. The incomplete cancellation of the projection components, mostly due to the limited scan angle in the conventional tomosynthesis scan geometry, often makes the image contrast too low to differentiate the malignant tissues from the background tissues with confidence. In this paper, we propose a new method to suppress the inter-plane artifacts in FPD-based tomosynthesis. If 3D whole volume CT images are available before the tomosynthesis scan, the CT image data can be incorporated into the tomosynthesis image reconstruction to suppress the inter-plane artifacts, hence, improving the image contrast. In the proposed technique, the projection components stemming from outside the region-of-interest (ROI) are subtracted from the measured tomosynthesis projection data to suppress the inter-plane artifacts. The projection components stemming from outside the ROI are calculated from the 3D whole volume CT images which usually have lower lateral resolution than the tomosynthesis images. The tomosynthesis images are reconstructed from the subtracted projection data which account for the x-ray attenuation through the ROI. After verifying the proposed method by simulation, we have performed both CT scan and tomosynthesis scan on a phantom and a sacrificed rat using a FPD-based micro-CT. We have measured contrast-to-noise ratio (CNR) from the tomosynthesis images which is an indicator of the residual inter-plane artifacts on the focal-plane image. In both cases of the simulation and experimental imaging studies of the contrast evaluating phantom, CNRs have been significantly improved by the proposed method. In the rat imaging also, we have observed better visual contrast from the tomosynthesis images reconstructed by the proposed method. The

  8. Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

    SciTech Connect

    Ravindran, V. R.; Sreelakshmi, C.; Vibin

    2008-09-26

    The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

  9. Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

    NASA Astrophysics Data System (ADS)

    Ravindran, V. R.; Sreelakshmi, C.; Vibin, Vibin

    2008-09-01

    The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

  10. Factors Affecting Dimensional Accuracy of 3-D Printed Anatomical Structures Derived from CT Data.

    PubMed

    Ogden, Kent M; Aslan, Can; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Soman, Pranav

    2015-12-01

    Additive manufacturing and bio-printing, with the potential for direct fabrication of complex patient-specific anatomies derived from medical scan data, are having an ever-increasing impact on the practice of medicine. Anatomic structures are typically derived from CT or MRI scans, and there are multiple steps in the model derivation process that influence the geometric accuracy of the printed constructs. In this work, we compare the dimensional accuracy of 3-D printed constructs of an L1 vertebra derived from CT data for an ex vivo cadaver T-L spine with the original vertebra. Processing of segmented structures using binary median filters and various surface extraction algorithms is evaluated for the effect on model dimensions. We investigate the effects of changing CT reconstruction kernels by scanning simple geometric objects and measuring the impact on the derived model dimensions. We also investigate if there are significant differences between physical and virtual model measurements. The 3-D models were printed using a commercial 3-D printer, the Replicator 2 (MakerBot, Brooklyn, NY) using polylactic acid (PLA) filament. We found that changing parameters during the scan reconstruction, segmentation, filtering, and surface extraction steps will have an effect on the dimensions of the final model. These effects need to be quantified for specific situations that rely on the accuracy of 3-D printed models used in medicine or tissue engineering applications.

  11. [Design of a 3D afterloading brachytherapy simulation system based on CT images].

    PubMed

    Yu, Hui; Xu, Hai-Rong; Zhang, Shu-Xu; Shi, Yu-Sheng; Qian, Jian-Yang

    2008-03-01

    To design a new afterloading brachytherapy simulation system based on CT images. This paper mainly focuses on the anthropomorphic pelvic phantom spiled by three pipelines and the nasopharyngeal carcinoma spiled by two pipelines. Microsoft Visual C++ was used to parse CT images for some information, then to reconstruct pipelines in the body of phantom or the patient and to give the three-dimensional coordinate of dwelling points. The dose distribution displayed on CT images was processed by the dose distribution calculation methods near single afterloading source and the dose optimization methods. VTK technology was used in the 3D display in the system. According to the reference points applied by doctors, the system can calculate reversely the dwelling time of dwelling points in pipelines and get satisfying dose distribution on CT images. Besides, it can reflect the 3D relationship between the dose volume and the normal tissues. This system overcomes some deficiencies of 2D afterloading brachytherapy simulation system based on X-ray films which are used widely in China. It supplies 3D display of dose distribution for clinical doctors. At present, the system is being tested in clinics.

  12. SU-E-J-209: Verification of 3D Surface Registration Between Stereograms and CT Images

    SciTech Connect

    Han, T; Gifford, K; Smith, B; Salehpour, M

    2014-06-01

    Purpose: Stereography can provide a visualization of the skin surface for radiation therapy patients. The aim of this study was to verify the registration algorithm in a commercial image analysis software, 3dMDVultus, for the fusion of stereograms and CT images. Methods: CT and stereographic scans were acquired of a head phantom and a deformable phantom. CT images were imported in 3dMDVultus and the surface contours were generated by threshold segmentation. Stereograms were reconstructed in 3dMDVultus. The resulting surfaces were registered with Vultus algorithm and then exported to in-house registration software and compared with four algorithms: rigid, affine, non-rigid iterative closest point (ICP) and b-spline algorithm. RMS (root-mean-square residuals of the surface point distances) error between the registered CT and stereogram surfaces was calculated and analyzed. Results: For the head phantom, the maximum RMS error between registered CT surfaces to stereogram was 6.6 mm for Vultus algorithm, whereas the mean RMS error was 0.7 mm. For the deformable phantom, the maximum RMS error was 16.2 mm for Vultus algorithm, whereas the mean RMS error was 4.4 mm. Non-rigid ICP demonstrated the best registration accuracy, as the mean of RMS errors were both within 1 mm. Conclusion: The accuracy of registration algorithm in 3dMDVultus was verified and exceeded RMS of 2 mm for deformable cases. Non-rigid ICP and b-spline algorithms improve the registration accuracy for both phantoms, especially in deformable one. For those patients whose body habitus deforms during radiation therapy, more advanced nonrigid algorithms need to be used.

  13. 3D-SIFT-Flow for atlas-based CT liver image segmentation

    SciTech Connect

    Xu, Yan; Xu, Chenchao Kuang, Xiao; Wang, Hongkai; Chang, Eric I-Chao; Huang, Weimin; Fan, Yubo

    2016-05-15

    Purpose: In this paper, the authors proposed a new 3D registration algorithm, 3D-scale invariant feature transform (SIFT)-Flow, for multiatlas-based liver segmentation in computed tomography (CT) images. Methods: In the registration work, the authors developed a new registration method that takes advantage of dense correspondence using the informative and robust SIFT feature. The authors computed the dense SIFT features for the source image and the target image and designed an objective function to obtain the correspondence between these two images. Labeling of the source image was then mapped to the target image according to the former correspondence, resulting in accurate segmentation. In the fusion work, the 2D-based nonparametric label transfer method was extended to 3D for fusing the registered 3D atlases. Results: Compared with existing registration algorithms, 3D-SIFT-Flow has its particular advantage in matching anatomical structures (such as the liver) that observe large variation/deformation. The authors observed consistent improvement over widely adopted state-of-the-art registration methods such as ELASTIX, ANTS, and multiatlas fusion methods such as joint label fusion. Experimental results of liver segmentation on the MICCAI 2007 Grand Challenge are encouraging, e.g., Dice overlap ratio 96.27% ± 0.96% by our method compared with the previous state-of-the-art result of 94.90% ± 2.86%. Conclusions: Experimental results show that 3D-SIFT-Flow is robust for segmenting the liver from CT images, which has large tissue deformation and blurry boundary, and 3D label transfer is effective and efficient for improving the registration accuracy.

  14. 3D-SIFT-Flow for atlas-based CT liver image segmentation.

    PubMed

    Xu, Yan; Xu, Chenchao; Kuang, Xiao; Wang, Hongkai; Chang, Eric I-Chao; Huang, Weimin; Fan, Yubo

    2016-05-01

    In this paper, the authors proposed a new 3D registration algorithm, 3D-scale invariant feature transform (SIFT)-Flow, for multiatlas-based liver segmentation in computed tomography (CT) images. In the registration work, the authors developed a new registration method that takes advantage of dense correspondence using the informative and robust SIFT feature. The authors computed the dense SIFT features for the source image and the target image and designed an objective function to obtain the correspondence between these two images. Labeling of the source image was then mapped to the target image according to the former correspondence, resulting in accurate segmentation. In the fusion work, the 2D-based nonparametric label transfer method was extended to 3D for fusing the registered 3D atlases. Compared with existing registration algorithms, 3D-SIFT-Flow has its particular advantage in matching anatomical structures (such as the liver) that observe large variation/deformation. The authors observed consistent improvement over widely adopted state-of-the-art registration methods such as ELASTIX, ANTS, and multiatlas fusion methods such as joint label fusion. Experimental results of liver segmentation on the MICCAI 2007 Grand Challenge are encouraging, e.g., Dice overlap ratio 96.27% ± 0.96% by our method compared with the previous state-of-the-art result of 94.90% ± 2.86%. Experimental results show that 3D-SIFT-Flow is robust for segmenting the liver from CT images, which has large tissue deformation and blurry boundary, and 3D label transfer is effective and efficient for improving the registration accuracy.

  15. Segmentation of brain blood vessels using projections in 3-D CT angiography images.

    PubMed

    Babin, Danilo; Vansteenkiste, Ewout; Pizurica, Aleksandra; Philips, Wilfried

    2011-01-01

    Segmenting cerebral blood vessels is of great importance in diagnostic and clinical applications, especially in quantitative diagnostics and surgery on aneurysms and arteriovenous malformations (AVM). Segmentation of CT angiography images requires algorithms robust to high intensity noise, while being able to segment low-contrast vessels. Because of this, most of the existing methods require user intervention. In this work we propose an automatic algorithm for efficient segmentation of 3-D CT angiography images of cerebral blood vessels. Our method is robust to high intensity noise and is able to accurately segment blood vessels with high range of luminance values, as well as low-contrast vessels.

  16. Computer-aided diagnosis for osteoporosis using chest 3D CT images

    NASA Astrophysics Data System (ADS)

    Yoneda, K.; Matsuhiro, M.; Suzuki, H.; Kawata, Y.; Niki, N.; Nakano, Y.; Ohmatsu, H.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, M.

    2016-03-01

    The patients of osteoporosis comprised of about 13 million people in Japan and it is one of the problems the aging society has. In order to prevent the osteoporosis, it is necessary to do early detection and treatment. Multi-slice CT technology has been improving the three dimensional (3-D) image analysis with higher body axis resolution and shorter scan time. The 3-D image analysis using multi-slice CT images of thoracic vertebra can be used as a support to diagnose osteoporosis and at the same time can be used for lung cancer diagnosis which may lead to early detection. We develop automatic extraction and partitioning algorithm for spinal column by analyzing vertebral body structure, and the analysis algorithm of the vertebral body using shape analysis and a bone density measurement for the diagnosis of osteoporosis. Osteoporosis diagnosis support system obtained high extraction rate of the thoracic vertebral in both normal and low doses.

  17. A case of pulmonary artery intimal sarcoma diagnosed with multislice CT scan with 3D reconstruction.

    PubMed

    Choi, Eui-Young; Yoon, Young-Won; Kwon, Hyuck Moon; Kim, Dongsoo; Park, Byung-Eun; Hong, Yoo-Sun; Koo, Ja-Seung; Kim, Tae-Hoon; Kim, Hyun-Seung

    2004-06-30

    Pulmonary artery intimal sarcoma is a rare highly lethal disease, with additional retrograde extension to pulmonic valve and right ventricle being an extremely rare condition. It is frequently mistaken for pulmonary thromboembolism. We report a case of 64-year-old woman with progressive dyspnea initially suspected and treated for pulmonary thromboembolism. Her helical chest CT scan with 3 dimensional (3D) reconstruction combined with echocardiography revealed a compacting main pulmonary artery mass extending to the right ventricular outflow tract and the right pulmonary artery. After excision of the mass, the patient's condition improved dramatically, and the pathologic findings revealed pulmonary intimal sarcoma. This report emphasizes that helical chest CT with 3D reconstruction can be an important tool to differentiate the characteristics of pulmonary artery lesions, such as intimal sarcoma and thromboembolism.

  18. Volumetric CT-based segmentation of NSCLC using 3D-Slicer

    NASA Astrophysics Data System (ADS)

    Velazquez, Emmanuel Rios; Parmar, Chintan; Jermoumi, Mohammed; Mak, Raymond H.; van Baardwijk, Angela; Fennessy, Fiona M.; Lewis, John H.; de Ruysscher, Dirk; Kikinis, Ron; Lambin, Philippe; Aerts, Hugo J. W. L.

    2013-12-01

    Accurate volumetric assessment in non-small cell lung cancer (NSCLC) is critical for adequately informing treatments. In this study we assessed the clinical relevance of a semiautomatic computed tomography (CT)-based segmentation method using the competitive region-growing based algorithm, implemented in the free and public available 3D-Slicer software platform. We compared the 3D-Slicer segmented volumes by three independent observers, who segmented the primary tumour of 20 NSCLC patients twice, to manual slice-by-slice delineations of five physicians. Furthermore, we compared all tumour contours to the macroscopic diameter of the tumour in pathology, considered as the ``gold standard''. The 3D-Slicer segmented volumes demonstrated high agreement (overlap fractions > 0.90), lower volume variability (p = 0.0003) and smaller uncertainty areas (p = 0.0002), compared to manual slice-by-slice delineations. Furthermore, 3D-Slicer segmentations showed a strong correlation to pathology (r = 0.89, 95%CI, 0.81-0.94). Our results show that semiautomatic 3D-Slicer segmentations can be used for accurate contouring and are more stable than manual delineations. Therefore, 3D-Slicer can be employed as a starting point for treatment decisions or for high-throughput data mining research, such as Radiomics, where manual delineating often represent a time-consuming bottleneck.

  19. Volumetric CT-based segmentation of NSCLC using 3D-Slicer

    PubMed Central

    Velazquez, Emmanuel Rios; Parmar, Chintan; Jermoumi, Mohammed; Mak, Raymond H.; van Baardwijk, Angela; Fennessy, Fiona M.; Lewis, John H.; De Ruysscher, Dirk; Kikinis, Ron; Lambin, Philippe; Aerts, Hugo J. W. L.

    2013-01-01

    Accurate volumetric assessment in non-small cell lung cancer (NSCLC) is critical for adequately informing treatments. In this study we assessed the clinical relevance of a semiautomatic computed tomography (CT)-based segmentation method using the competitive region-growing based algorithm, implemented in the free and public available 3D-Slicer software platform. We compared the 3D-Slicer segmented volumes by three independent observers, who segmented the primary tumour of 20 NSCLC patients twice, to manual slice-by-slice delineations of five physicians. Furthermore, we compared all tumour contours to the macroscopic diameter of the tumour in pathology, considered as the “gold standard”. The 3D-Slicer segmented volumes demonstrated high agreement (overlap fractions > 0.90), lower volume variability (p = 0.0003) and smaller uncertainty areas (p = 0.0002), compared to manual slice-by-slice delineations. Furthermore, 3D-Slicer segmentations showed a strong correlation to pathology (r = 0.89, 95%CI, 0.81–0.94). Our results show that semiautomatic 3D-Slicer segmentations can be used for accurate contouring and are more stable than manual delineations. Therefore, 3D-Slicer can be employed as a starting point for treatment decisions or for high-throughput data mining research, such as Radiomics, where manual delineating often represent a time-consuming bottleneck. PMID:24346241

  20. A fast 3D region growing approach for CT angiography applications

    NASA Astrophysics Data System (ADS)

    Ye, Zhen; Lin, Zhongmin; Lu, Cheng-chang

    2004-05-01

    Region growing is one of the most popular methods for low-level image segmentation. Many researches on region growing have focused on the definition of the homogeneity criterion or growing and merging criterion. However, one disadvantage of conventional region growing is redundancy. It requires a large memory usage, and the computation-efficiency is very low especially for 3D images. To overcome this problem, a non-recursive single-pass 3D region growing algorithm named SymRG is implemented and successfully applied to 3D CT angiography (CTA) applications for vessel segmentation and bone removal. The method consists of three steps: segmenting one-dimensional regions of each row; doing region merging to adjacent rows to obtain the region segmentation of each slice; and doing region merging to adjacent slices to obtain the final region segmentation of 3D images. To improve the segmentation speed for very large volume 3D CTA images, this algorithm is applied repeatedly to newly updated local cubes. The next new cube can be estimated by checking isolated segmented regions on all 6 faces of the current local cube. This local non-recursive 3D region-growing algorithm is memory-efficient and computation-efficient. Clinical testings of this algorithm on Brain CTA show this technique could effectively remove whole skull, most of the bones on the skull base, and reveal the cerebral vascular structures clearly.

  1. A universal approach for automatic organ segmentations on 3D CT images based on organ localization and 3D GrabCut

    NASA Astrophysics Data System (ADS)

    Zhou, Xiangrong; Ito, Takaaki; Zhou, Xinxin; Chen, Huayue; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

    2014-03-01

    This paper describes a universal approach to automatic segmentation of different internal organ and tissue regions in three-dimensional (3D) computerized tomography (CT) scans. The proposed approach combines object localization, a probabilistic atlas, and 3D GrabCut techniques to achieve automatic and quick segmentation. The proposed method first detects a tight 3D bounding box that contains the target organ region in CT images and then estimates the prior of each pixel inside the bounding box belonging to the organ region or background based on a dynamically generated probabilistic atlas. Finally, the target organ region is separated from the background by using an improved 3D GrabCut algorithm. A machine-learning method is used to train a detector to localize the 3D bounding box of the target organ using template matching on a selected feature space. A content-based image retrieval method is used for online generation of a patient-specific probabilistic atlas for the target organ based on a database. A 3D GrabCut algorithm is used for final organ segmentation by iteratively estimating the CT number distributions of the target organ and backgrounds using a graph-cuts algorithm. We applied this approach to localize and segment twelve major organ and tissue regions independently based on a database that includes 1300 torso CT scans. In our experiments, we randomly selected numerous CT scans and manually input nine principal types of inner organ regions for performance evaluation. Preliminary results showed the feasibility and efficiency of the proposed approach for addressing automatic organ segmentation issues on CT images.

  2. Massive-training support vector regression and Gaussian process for false-positive reduction in computer-aided detection of polyps in CT colonography.

    PubMed

    Xu, Jian-Wu; Suzuki, Kenji

    2011-04-01

    A massive-training artificial neural network (MTANN) has been developed for the reduction of false positives (FPs) in computer-aided detection (CADe) of polyps in CT colonography (CTC). A major limitation of the MTANN is the long training time. To address this issue, the authors investigated the feasibility of two state-of-the-art regression models, namely, support vector regression (SVR) and Gaussian process regression (GPR) models, in the massive-training framework and developed massive-training SVR (MTSVR) and massive-training GPR (MTGPR) for the reduction of FPs in CADe of polyps. The authors applied SVR and GPR as volume-processing techniques in the distinction of polyps from FP detections in a CTC CADe scheme. Unlike artificial neural networks (ANNs), both SVR and GPR are memory-based methods that store a part of or the entire training data for testing. Therefore, their training is generally fast and they are able to improve the efficiency of the massive-training methodology. Rooted in a maximum margin property, SVR offers excellent generalization ability and robustness to outliers. On the other hand, GPR approaches nonlinear regression from a Bayesian perspective, which produces both the optimal estimated function and the covariance associated with the estimation. Therefore, both SVR and GPR, as the state-of-the-art nonlinear regression models, are able to offer a performance comparable or potentially superior to that of ANN, with highly efficient training. Both MTSVR and MTGPR were trained directly with voxel values from CTC images. A 3D scoring method based on a 3D Gaussian weighting function was applied to the outputs of MTSVR and MTGPR for distinction between polyps and nonpolyps. To test the performance of the proposed models, the authors compared them to the original MTANN in the distinction between actual polyps and various types of FPs in terms of training time reduction and FP reduction performance. The authors' CTC database consisted of 240 CTC

  3. Massive-training support vector regression and Gaussian process for false-positive reduction in computer-aided detection of polyps in CT colonography

    PubMed Central

    Xu, Jian-Wu; Suzuki, Kenji

    2011-01-01

    Purpose: A massive-training artificial neural network (MTANN) has been developed for the reduction of false positives (FPs) in computer-aided detection (CADe) of polyps in CT colonography (CTC). A major limitation of the MTANN is the long training time. To address this issue, the authors investigated the feasibility of two state-of-the-art regression models, namely, support vector regression (SVR) and Gaussian process regression (GPR) models, in the massive-training framework and developed massive-training SVR (MTSVR) and massive-training GPR (MTGPR) for the reduction of FPs in CADe of polyps. Methods: The authors applied SVR and GPR as volume-processing techniques in the distinction of polyps from FP detections in a CTC CADe scheme. Unlike artificial neural networks (ANNs), both SVR and GPR are memory-based methods that store a part of or the entire training data for testing. Therefore, their training is generally fast and they are able to improve the efficiency of the massive-training methodology. Rooted in a maximum margin property, SVR offers excellent generalization ability and robustness to outliers. On the other hand, GPR approaches nonlinear regression from a Bayesian perspective, which produces both the optimal estimated function and the covariance associated with the estimation. Therefore, both SVR and GPR, as the state-of-the-art nonlinear regression models, are able to offer a performance comparable or potentially superior to that of ANN, with highly efficient training. Both MTSVR and MTGPR were trained directly with voxel values from CTC images. A 3D scoring method based on a 3D Gaussian weighting function was applied to the outputs of MTSVR and MTGPR for distinction between polyps and nonpolyps. To test the performance of the proposed models, the authors compared them to the original MTANN in the distinction between actual polyps and various types of FPs in terms of training time reduction and FP reduction performance. The authors’ CTC database

  4. Computerized detection of colorectal masses in CT colonography based on fuzzy merging and wall-thickening analysis.

    PubMed

    Näppi, Janne J; Frimmel, Hans; Dachman, Abraham H; Yoshida, Hiroyuki

    2004-04-01

    In recent years, several computer-aided detection (CAD) schemes have been developed for the detection of polyps in CT colonography (CTC). However, few studies have addressed the problem of computerized detection of colorectal masses in CTC. This is mostly because masses are considered to be well visualized by a radiologist because of their size and invasiveness. Nevertheless, the automated detection of masses would naturally complement the automated detection of polyps in CTC and would produce a more comprehensive computer aid to radiologists. Therefore, in this study, we identified some of the problems involved with the computerized detection of masses, and we developed a scheme for the computerized detection of masses that can be integrated into a CAD scheme for the detection of polyps. The performance of the mass detection scheme was evaluated by application to clinical CTC data sets. CTC was performed on 82 patients with helical CT scanners and reconstruction intervals of 1.0-5.0 mm in the supine and prone positions. Fourteen patients (17%) had a total of 14 masses of 30-50 mm, and sixteen patients (20%) had a total of 30 polyps 5-25 mm in diameter. Four patients had both polyps and masses. Fifty-six of the patients (68%) were normal. The CTC data were interpolated linearly to yield isotropic data sets, and the colon was extracted by use of a knowledge-guided segmentation technique. Two methods, fuzzy merging and wall-thickening analysis, were developed for the detection of masses. The fuzzy merging method detected masses with a significant intraluminal component by separating the initial CAD detections of locally cap-like shapes within the colonic wall into mass candidates and polyp candidates. The wall-thickening analysis detected nonintraluminal masses by searching the colonic wall for abnormal thickening. The final regions of the mass candidates were extracted by use of a level set method based on a fast marching algorithm. False-positive (FP) detections

  5. Imaging Properties of 3D Printed Materials: Multi-Energy CT of Filament Polymers.

    PubMed

    Shin, James; Sandhu, Ranjit S; Shih, George

    2017-02-06

    Clinical applications of 3D printing are increasingly commonplace, likewise the frequency of inclusion of 3D printed objects on imaging studies. Although there is a general familiarity with the imaging appearance of traditional materials comprising common surgical hardware and medical devices, comparatively less is known regarding the appearance of available 3D printing materials in the consumer market. This work detailing the CT appearance of a selected number of common filament polymer classes is an initial effort to catalog these data, to provide for accurate interpretation of imaging studies incidentally or intentionally including fabricated objects. Furthermore, this information can inform the design of image-realistic tissue-mimicking phantoms for a variety of applications, with clear candidate material analogs for bone, soft tissue, water, and fat attenuation.

  6. Two-alternative forced-choice evaluation of 3D CT angiograms

    NASA Astrophysics Data System (ADS)

    Habets, Damiaan F.; Chapman, Brian E.; Fox, Allan J.; Hyde, Derek E.; Holdsworth, David W.

    2001-06-01

    This study describes the development and evaluation of an appropriate methodology to study observer performance when comparing 2D and 3D angiographic techniques. 3D-CT angiograms were obtained from patients with cerebral aneurysms or occlusive carotid artery disease and perspective rendering of this 3D data was performed to produce maximum intensity projections (MIP) at view angles identical to digital subtraction angiography (DSA) images. Two-alternative-forced-choice methodology (2AFC) was then used to determine the percent correct (Pc), which is equivalent to the area Az under the receiver-operating characteristic (RTOC) curve. In a comparison of CRA MIP images and DSA images of the intracranial vasculature, the average value of Pc was 0.90+/- 0.03. Perspective reprojection produces digitally reconstructed radiographs (DRRs) with image quality that is nearly equivalent to conventional DSA, with the additional clinical advantage of providing digitally reconstructed images at an unlimited number of viewing angles.

  7. Digimouse: a 3D whole body mouse atlas from CT and cryosection data

    NASA Astrophysics Data System (ADS)

    Dogdas, Belma; Stout, David; Chatziioannou, Arion F.; Leahy, Richard M.

    2007-02-01

    We have constructed a three-dimensional (3D) whole body mouse atlas from coregistered x-ray CT and cryosection data of a normal nude male mouse. High quality PET, x-ray CT and cryosection images were acquired post mortem from a single mouse placed in a stereotactic frame with fiducial markers visible in all three modalities. The image data were coregistered to a common coordinate system using the fiducials and resampled to an isotropic 0.1 mm voxel size. Using interactive editing tools we segmented and labelled whole brain, cerebrum, cerebellum, olfactory bulbs, striatum, medulla, masseter muscles, eyes, lachrymal glands, heart, lungs, liver, stomach, spleen, pancreas, adrenal glands, kidneys, testes, bladder, skeleton and skin surface. The final atlas consists of the 3D volume, in which the voxels are labelled to define the anatomical structures listed above, with coregistered PET, x-ray CT and cryosection images. To illustrate use of the atlas we include simulations of 3D bioluminescence and PET image reconstruction. Optical scatter and absorption values are assigned to each organ to simulate realistic photon transport within the animal for bioluminescence imaging. Similarly, 511 keV photon attenuation values are assigned to each structure in the atlas to simulate realistic photon attenuation in PET. The Digimouse atlas and data are available at http://neuroimage.usc.edu/Digimouse.html.

  8. Digimouse: a 3D whole body mouse atlas from CT and cryosection data.

    PubMed

    Dogdas, Belma; Stout, David; Chatziioannou, Arion F; Leahy, Richard M

    2007-02-07

    We have constructed a three-dimensional (3D) whole body mouse atlas from coregistered x-ray CT and cryosection data of a normal nude male mouse. High quality PET, x-ray CT and cryosection images were acquired post mortem from a single mouse placed in a stereotactic frame with fiducial markers visible in all three modalities. The image data were coregistered to a common coordinate system using the fiducials and resampled to an isotropic 0.1 mm voxel size. Using interactive editing tools we segmented and labelled whole brain, cerebrum, cerebellum, olfactory bulbs, striatum, medulla, masseter muscles, eyes, lachrymal glands, heart, lungs, liver, stomach, spleen, pancreas, adrenal glands, kidneys, testes, bladder, skeleton and skin surface. The final atlas consists of the 3D volume, in which the voxels are labelled to define the anatomical structures listed above, with coregistered PET, x-ray CT and cryosection images. To illustrate use of the atlas we include simulations of 3D bioluminescence and PET image reconstruction. Optical scatter and absorption values are assigned to each organ to simulate realistic photon transport within the animal for bioluminescence imaging. Similarly, 511 keV photon attenuation values are assigned to each structure in the atlas to simulate realistic photon attenuation in PET. The Digimouse atlas and data are available at http://neuroimage.usc.edu/Digimouse.html.

  9. Performance of a commercial optical CT scanner and polymer gel dosimeters for 3-D dose verification.

    PubMed

    Xu, Y; Wuu, Cheng-Shie; Maryanski, Marek J

    2004-11-01

    Performance analysis of a commercial three-dimensional (3-D) dose mapping system based on optical CT scanning of polymer gels is presented. The system consists of BANG 3 polymer gels (MGS Research, Inc., Madison, CT), OCTOPUS laser CT scanner (MGS Research, Inc., Madison, CT), and an in-house developed software for optical CT image reconstruction and 3-D dose distribution comparison between the gel, film measurements and the radiation therapy treatment plans. Various sources of image noise (digitization, electronic, optical, and mechanical) generated by the scanner as well as optical uniformity of the polymer gel are analyzed. The performance of the scanner is further evaluated in terms of the reproducibility of the data acquisition process, the uncertainties at different levels of reconstructed optical density per unit length and the effects of scanning parameters. It is demonstrated that for BANG 3 gel phantoms held in cylindrical plastic containers, the relative dose distribution can be reproduced by the scanner with an overall uncertainty of about 3% within approximately 75% of the radius of the container. In regions located closer to the container wall, however, the scanner generates erroneous optical density values that arise from the reflection and refraction of the laser rays at the interface between the gel and the container. The analysis of the accuracy of the polymer gel dosimeter is exemplified by the comparison of the gel/OCT-derived dose distributions with those from film measurements and a commercial treatment planning system (Cadplan, Varian Corporation, Palo Alto, CA) for a 6 cm x 6 cm single field of 6 MV x rays and a 3-D conformal radiotherapy (3DCRT) plan. The gel measurements agree with the treatment plans and the film measurements within the "3%-or-2 mm" criterion throughout the usable, artifact-free central region of the gel volume. Discrepancies among the three data sets are analyzed.

  10. Performance of a commercial optical CT scanner and polymer gel dosimeters for 3-D dose verification

    SciTech Connect

    Xu, Y.; Wuu, C.-S.; Maryanski, Marek J.

    2004-11-01

    Performance analysis of a commercial three-dimensional (3-D) dose mapping system based on optical CT scanning of polymer gels is presented. The system consists of BANG{sup reg}3 polymer gels (MGS Research, Inc., Madison, CT), OCTOPUS{sup TM} laser CT scanner (MGS Research, Inc., Madison, CT), and an in-house developed software for optical CT image reconstruction and 3-D dose distribution comparison between the gel, film measurements and the radiation therapy treatment plans. Various sources of image noise (digitization, electronic, optical, and mechanical) generated by the scanner as well as optical uniformity of the polymer gel are analyzed. The performance of the scanner is further evaluated in terms of the reproducibility of the data acquisition process, the uncertainties at different levels of reconstructed optical density per unit length and the effects of scanning parameters. It is demonstrated that for BANG{sup registered}3 gel phantoms held in cylindrical plastic containers, the relative dose distribution can be reproduced by the scanner with an overall uncertainty of about 3% within approximately 75% of the radius of the container. In regions located closer to the container wall, however, the scanner generates erroneous optical density values that arise from the reflection and refraction of the laser rays at the interface between the gel and the container. The analysis of the accuracy of the polymer gel dosimeter is exemplified by the comparison of the gel/OCT-derived dose distributions with those from film measurements and a commercial treatment planning system (Cadplan, Varian Corporation, Palo Alto, CA) for a 6 cmx6 cm single field of 6 MV x rays and a 3-D conformal radiotherapy (3DCRT) plan. The gel measurements agree with the treatment plans and the film measurements within the '3%-or-2 mm' criterion throughout the usable, artifact-free central region of the gel volume. Discrepancies among the three data sets are analyzed.

  11. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    PubMed Central

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-01-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images. PMID:26980176

  12. 3D Convolutional Neural Network for Automatic Detection of Lung Nodules in Chest CT

    PubMed Central

    Hamidian, Sardar; Sahiner, Berkman; Petrick, Nicholas; Pezeshk, Aria

    2017-01-01

    Deep convolutional neural networks (CNNs) form the backbone of many state-of-the-art computer vision systems for classification and segmentation of 2D images. The same principles and architectures can be extended to three dimensions to obtain 3D CNNs that are suitable for volumetric data such as CT scans. In this work, we train a 3D CNN for automatic detection of pulmonary nodules in chest CT images using volumes of interest extracted from the LIDC dataset. We then convert the 3D CNN which has a fixed field of view to a 3D fully convolutional network (FCN) which can generate the score map for the entire volume efficiently in a single pass. Compared to the sliding window approach for applying a CNN across the entire input volume, the FCN leads to a nearly 800-fold speed-up, and thereby fast generation of output scores for a single case. This screening FCN is used to generate difficult negative examples that are used to train a new discriminant CNN. The overall system consists of the screening FCN for fast generation of candidate regions of interest, followed by the discrimination CNN. PMID:28845077

  13. 3D convolutional neural network for automatic detection of lung nodules in chest CT

    NASA Astrophysics Data System (ADS)

    Hamidian, Sardar; Sahiner, Berkman; Petrick, Nicholas; Pezeshk, Aria

    2017-03-01

    Deep convolutional neural networks (CNNs) form the backbone of many state-of-the-art computer vision systems for classification and segmentation of 2D images. The same principles and architectures can be extended to three dimensions to obtain 3D CNNs that are suitable for volumetric data such as CT scans. In this work, we train a 3D CNN for automatic detection of pulmonary nodules in chest CT images using volumes of interest extracted from the LIDC dataset. We then convert the 3D CNN which has a fixed field of view to a 3D fully convolutional network (FCN) which can generate the score map for the entire volume efficiently in a single pass. Compared to the sliding window approach for applying a CNN across the entire input volume, the FCN leads to a nearly 800-fold speed-up, and thereby fast generation of output scores for a single case. This screening FCN is used to generate difficult negative examples that are used to train a new discriminant CNN. The overall system consists of the screening FCN for fast generation of candidate regions of interest, followed by the discrimination CNN.

  14. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation.

    PubMed

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-16

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  15. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    NASA Astrophysics Data System (ADS)

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  16. The CT-PPS tracking system with 3D pixel detectors

    NASA Astrophysics Data System (ADS)

    Ravera, F.

    2016-11-01

    The CMS-TOTEM Precision Proton Spectrometer (CT-PPS) detector will be installed in Roman pots (RP) positioned on either side of CMS, at about 210 m from the interaction point. This detector will measure leading protons, allowing detailed studies of diffractive physics and central exclusive production in standard LHC running conditions. An essential component of the CT-PPS apparatus is the tracking system, which consists of two detector stations per arm equipped with six 3D silicon pixel-sensor modules, each read out by six PSI46dig chips. The front-end electronics has been designed to fulfill the mechanical constraints of the RP and to be compatible as much as possible with the readout chain of the CMS pixel detector. The tracking system is currently under construction and will be installed by the end of 2016. In this contribution the final design and the expected performance of the CT-PPS tracking system is presented. A summary of the studies performed, before and after irradiation, on the 3D detectors produced for CT-PPS is given.

  17. A positioning QA procedure for 2D/2D (kV/MV) and 3D/3D (CT/CBCT) image matching for radiotherapy patient setup.

    PubMed

    Guan, Huaiqun; Hammoud, Rabih; Yin, Fang-Fang

    2009-10-06

    A positioning QA procedure for Varian's 2D/2D (kV/MV) and 3D/3D (planCT/CBCT) matching was developed. The procedure was to check: (1) the coincidence of on-board imager (OBI), portal imager (PI), and cone beam CT (CBCT)'s isocenters (digital graticules) to a linac's isocenter (to a pre-specified accuracy); (2) that the positioning difference detected by 2D/2D (kV/MV) and 3D/3D(planCT/CBCT) matching can be reliably transferred to couch motion. A cube phantom with a 2 mm metal ball (bb) at the center was used. The bb was used to define the isocenter. Two additional bbs were placed on two phantom surfaces in order to define a spatial location of 1.5 cm anterior, 1.5 cm inferior, and 1.5 cm right from the isocenter. An axial scan of the phantom was acquired from a multislice CT simulator. The phantom was set at the linac's isocenter (lasers); either AP MV/R Lat kV images or CBCT images were taken for 2D/2D or 3D/3D matching, respectively. For 2D/2D, the accuracy of each device's isocenter was obtained by checking the distance between the central bb and the digital graticule. Then the central bb in orthogonal DRRs was manually moved to overlay to the off-axis bbs in kV/MV images. For 3D/3D, CBCT was first matched to planCT to check the isocenter difference between the two CTs. Manual shifts were then made by moving CBCT such that the point defined by the two off-axis bbs overlay to the central bb in planCT. (PlanCT can not be moved in the current version of OBI1.4.) The manual shifts were then applied to remotely move the couch. The room laser was used to check the accuracy of the couch movement. For Trilogy (or Ix-21) linacs, the coincidence of imager and linac's isocenter was better than 1 mm (or 1.5 mm). The couch shift accuracy was better than 2 mm.

  18. 3D SPECT/CT fusion using image data projection of bone SPECT onto 3D volume-rendered CT images: feasibility and clinical impact in the diagnosis of bone metastasis.

    PubMed

    Ogata, Yuji; Nakahara, Tadaki; Ode, Kenichi; Matsusaka, Yohji; Katagiri, Mari; Iwabuchi, Yu; Itoh, Kazunari; Ichimura, Akira; Jinzaki, Masahiro

    2017-05-01

    We developed a method of image data projection of bone SPECT into 3D volume-rendered CT images for 3D SPECT/CT fusion. The aims of our study were to evaluate its feasibility and clinical usefulness. Whole-body bone scintigraphy (WB) and SPECT/CT scans were performed in 318 cancer patients using a dedicated SPECT/CT systems. Volume data of bone SPECT and CT were fused to obtain 2D SPECT/CT images. To generate our 3D SPECT/CT images, colored voxel data of bone SPECT were projected onto the corresponding location of the volume-rendered CT data after a semi-automatic bone extraction. Then, the resultant 3D images were blended with conventional volume-rendered CT images, allowing to grasp the three-dimensional relationship between bone metabolism and anatomy. WB and SPECT (WB + SPECT), 2D SPECT/CT fusion, and 3D SPECT/CT fusion were evaluated by two independent reviewers in the diagnosis of bone metastasis. The inter-observer variability and diagnostic accuracy in these three image sets were investigated using a four-point diagnostic scale. Increased bone metabolism was found in 744 metastatic sites and 1002 benign changes. On a per-lesion basis, inter-observer agreements in the diagnosis of bone metastasis were 0.72 for WB + SPECT, 0.90 for 2D SPECT/CT, and 0.89 for 3D SPECT/CT. Receiver operating characteristic analyses for the diagnostic accuracy of bone metastasis showed that WB + SPECT, 2D SPECT/CT, and 3D SPECT/CT had an area under the curve of 0.800, 0.983, and 0.983 for reader 1, 0.865, 0.992, and 0.993 for reader 2, respectively (WB + SPECT vs. 2D or 3D SPECT/CT, p < 0.001; 2D vs. 3D SPECT/CT, n.s.). The durations of interpretation of WB + SPECT, 2D SPECT/CT, and 3D SPECT/CT images were 241 ± 75, 225 ± 73, and 182 ± 71 s for reader 1 and 207 ± 72, 190 ± 73, and 179 ± 73 s for reader 2, respectively. As a result, it took shorter time to read 3D SPECT/CT images than 2D SPECT/CT (p < 0.0001) or WB

  19. From CT scanning to 3-D printing technology for the preoperative planning in laparoscopic splenectomy.

    PubMed

    Pietrabissa, Andrea; Marconi, Stefania; Peri, Andrea; Pugliese, Luigi; Cavazzi, Emma; Vinci, Alessio; Botti, Marta; Auricchio, Ferdinando

    2016-01-01

    Three-dimensional printing technology is rapidly changing the way we produce all sort of objects, having also included medical applications. We embarked in a pilot study to assess the value of patient-specific 3-D physical manufacturing of spleno-pancreatic anatomy in helping during patient's counseling and for preoperative planning. Twelve patients scheduled for a laparoscopic splenectomy underwent contrast CT and subsequent post-processing to create virtual 3-D models of the target anatomy, and 3-D printing of the relative solid objects. The printing process, its cost and encountered problems were monitored and recorded. Patients were asked to rate the value of 3-D objects on a 1-5 scale in facilitating their understanding of the proposed procedure. Also 10 surgical residents were required to evaluate the perceived extra value of 3-D printing in the preoperative planning process. The post-processing analysis required an average of 2; 20 h was needed to physically print each model and 4 additional hours to finalize each object. The cost for the material employed for each object was around 300 euros. Ten patients gave a score of 5, two a score of 4. Six residents gave a score of 5, four a score of 4. Three-dimensional printing is helpful in understanding complex anatomy for educational purposes at all levels. Cost and working time to produce good quality objects are still considerable.

  20. 3D visualization of biomedical CT images based on OpenGL and VRML techniques

    NASA Astrophysics Data System (ADS)

    Yin, Meng; Luo, Qingming; Xia, Fuhua

    2002-04-01

    Current high-performance computers and advanced image processing capabilities have made the application of three- dimensional visualization objects in biomedical computer tomographic (CT) images facilitate the researches on biomedical engineering greatly. Trying to cooperate with the update technology using Internet, where 3D data are typically stored and processed on powerful servers accessible by using TCP/IP, we should hold the results of the isosurface be applied in medical visualization generally. Furthermore, this project is a future part of PACS system our lab is working on. So in this system we use the 3D file format VRML2.0, which is used through the Web interface for manipulating 3D models. In this program we implemented to generate and modify triangular isosurface meshes by marching cubes algorithm. Then we used OpenGL and MFC techniques to render the isosurface and manipulating voxel data. This software is more adequate visualization of volumetric data. The drawbacks are that 3D image processing on personal computers is rather slow and the set of tools for 3D visualization is limited. However, these limitations have not affected the applicability of this platform for all the tasks needed in elementary experiments in laboratory or data preprocessed.

  1. Supervised recursive segmentation of volumetric CT images for 3D reconstruction of lung and vessel tree.

    PubMed

    Li, Xuanping; Wang, Xue; Dai, Yixiang; Zhang, Pengbo

    2015-12-01

    Three dimensional reconstruction of lung and vessel tree has great significance to 3D observation and quantitative analysis for lung diseases. This paper presents non-sheltered 3D models of lung and vessel tree based on a supervised semi-3D lung tissues segmentation method. A recursive strategy based on geometric active contour is proposed instead of the "coarse-to-fine" framework in existing literature to extract lung tissues from the volumetric CT slices. In this model, the segmentation of the current slice is supervised by the result of the previous one slice due to the slight changes between adjacent slice of lung tissues. Through this mechanism, lung tissues in all the slices are segmented fast and accurately. The serious problems of left and right lungs fusion, caused by partial volume effects, and segmentation of pleural nodules can be settled meanwhile during the semi-3D process. The proposed scheme is evaluated by fifteen scans, from eight healthy participants and seven participants suffering from early-stage lung tumors. The results validate the good performance of the proposed method compared with the "coarse-to-fine" framework. The segmented datasets are utilized to reconstruct the non-sheltered 3D models of lung and vessel tree.

  2. CT image artifacts from brachytherapy seed implants: A postprocessing 3D adaptive median filter

    SciTech Connect

    Basran, Parminder S.; Robertson, Andrew; Wells, Derek

    2011-02-15

    Purpose: To design a postprocessing 3D adaptive median filter that minimizes streak artifacts and improves soft-tissue contrast in postoperative CT images of brachytherapy seed implantations. Methods: The filter works by identifying voxels that are likely streaks and estimating more reflective voxel intensity by using voxel intensities in adjacent CT slices and applying a median filter over voxels not identified as seeds. Median values are computed over a 5x5x5 mm region of interest (ROI) within the CT volume. An acrylic phantom simulating a clinical seed implant arrangement and containing nonradioactive seeds was created. Low contrast subvolumes of tissuelike material were also embedded in the phantom. Pre- and postprocessed image quality metrics were compared using the standard deviation of ROIs between the seeds, the CT numbers of low contrast ROIs embedded within the phantom, the signal to noise ratio (SNR), and the contrast to noise ratio (CNR) of the low contrast ROIs. The method was demonstrated with a clinical postimplant CT dataset. Results: After the filter was applied, the standard deviation of CT values in streak artifact regions was significantly reduced from 76.5 to 7.2 HU. Within the observable low contrast plugs, the mean of all ROI standard deviations was significantly reduced from 60.5 to 3.9 HU, SNR significantly increased from 2.3 to 22.4, and CNR significantly increased from 0.2 to 4.1 (all P<0.01). The mean CT in the low contrast plugs remained within 5 HU of the original values. Conclusion: An efficient postprocessing filter that does not require access to projection data, which can be applied irrespective of CT scan parameters has been developed, provided the slice thickness and spacing is 3 mm or less.

  3. Pulmonary nodule classification based on CT density distribution using 3D thoracic CT images

    NASA Astrophysics Data System (ADS)

    Kawata, Yoshiki; Niki, Noboru; Ohamatsu, Hironobu; Kusumoto, Masahiko; Kakinuma, Ryutaro; Mori, Kiyoshi; Yamada, Kozo; Nishiyama, Hiroyuki; Eguchi, Kenji; Kaneko, Masahiro; Moriyama, Noriyuki

    2004-04-01

    Computer-aided diagnosis (CAD) has been investigated to provide physicians with quantitative information, such as estimates of the malignant likelihood, to aid in the classification of abnormalities detected at screening of lung cancers. The purpose of this study is to develop a method for classifying nodule density patterns that provides information with respect to nodule statuses such as lesion stage. This method consists of three steps, nodule segmentation, histogram analysis of CT density inside nodule, and classifying nodules into five types based on histogram patterns. In this paper, we introduce a two-dimensional (2-D) joint histogram with respect to distance from nodule center and CT density inside nodule and explore numerical features with respect to shape and position of the joint histogram.

  4. Pore detection in Computed Tomography (CT) soil 3D images using singularity map analysis

    NASA Astrophysics Data System (ADS)

    Sotoca, Juan J. Martin; Tarquis, Ana M.; Saa Requejo, Antonio; Grau, Juan B.

    2016-04-01

    X-ray Computed Tomography (CT) images have significantly helped the study of the internal soil structure. This technique has two main advantages: 1) it is a non-invasive technique, i.e., it doesńt modify the internal soil structure, and 2) it provides a good resolution. The major disadvantage is that these images are sometimes low-contrast in the solid/pore interface. One of the main problems in analyzing soil structure through CT images is to segment them in solid/pore space. To do so, we have different segmentation techniques at our disposal that are mainly based on thresholding methods in which global or local thresholds are calculated to separate pore space from solid space. The aim of this presentation is to develop the fractal approach to soil structure using "singularity maps" and the "Concentration-Area (CA) method". We will establish an analogy between mineralization processes in ore deposits and morphogenesis processes in soils. Resulting from this analogy a new 3D segmentation method is proposed, the "3D Singularity-CA" method. A comparison with traditional 3D segmentation methods will be performed to show the main differences among them.

  5. Insight into 3D micro-CT data: exploring segmentation algorithms through performance metrics.

    PubMed

    Perciano, Talita; Ushizima, Daniela; Krishnan, Harinarayan; Parkinson, Dilworth; Larson, Natalie; Pelt, Daniël M; Bethel, Wes; Zok, Frank; Sethian, James

    2017-09-01

    Three-dimensional (3D) micro-tomography (µ-CT) has proven to be an important imaging modality in industry and scientific domains. Understanding the properties of material structure and behavior has produced many scientific advances. An important component of the 3D µ-CT pipeline is image partitioning (or image segmentation), a step that is used to separate various phases or components in an image. Image partitioning schemes require specific rules for different scientific fields, but a common strategy consists of devising metrics to quantify performance and accuracy. The present article proposes a set of protocols to systematically analyze and compare the results of unsupervised classification methods used for segmentation of synchrotron-based data. The proposed dataflow for Materials Segmentation and Metrics (MSM) provides 3D micro-tomography image segmentation algorithms, such as statistical region merging (SRM), k-means algorithm and parallel Markov random field (PMRF), while offering different metrics to evaluate segmentation quality, confidence and conformity with standards. Both experimental and synthetic data are assessed, illustrating quantitative results through the MSM dashboard, which can return sample information such as media porosity and permeability. The main contributions of this work are: (i) to deliver tools to improve material design and quality control; (ii) to provide datasets for benchmarking and reproducibility; (iii) to yield good practices in the absence of standards or ground-truth for ceramic composite analysis.

  6. Segmentation of bone structures in 3D CT images based on continuous max-flow optimization

    NASA Astrophysics Data System (ADS)

    Pérez-Carrasco, J. A.; Acha-Piñero, B.; Serrano, C.

    2015-03-01

    In this paper an algorithm to carry out the automatic segmentation of bone structures in 3D CT images has been implemented. Automatic segmentation of bone structures is of special interest for radiologists and surgeons to analyze bone diseases or to plan some surgical interventions. This task is very complicated as bones usually present intensities overlapping with those of surrounding tissues. This overlapping is mainly due to the composition of bones and to the presence of some diseases such as Osteoarthritis, Osteoporosis, etc. Moreover, segmentation of bone structures is a very time-consuming task due to the 3D essence of the bones. Usually, this segmentation is implemented manually or with algorithms using simple techniques such as thresholding and thus providing bad results. In this paper gray information and 3D statistical information have been combined to be used as input to a continuous max-flow algorithm. Twenty CT images have been tested and different coefficients have been computed to assess the performance of our implementation. Dice and Sensitivity values above 0.91 and 0.97 respectively were obtained. A comparison with Level Sets and thresholding techniques has been carried out and our results outperformed them in terms of accuracy.

  7. Automatic cerebrospinal fluid segmentation in non-contrast CT images using a 3D convolutional network

    NASA Astrophysics Data System (ADS)

    Patel, Ajay; van de Leemput, Sil C.; Prokop, Mathias; van Ginneken, Bram; Manniesing, Rashindra

    2017-03-01

    Segmentation of anatomical structures is fundamental in the development of computer aided diagnosis systems for cerebral pathologies. Manual annotations are laborious, time consuming and subject to human error and observer variability. Accurate quantification of cerebrospinal fluid (CSF) can be employed as a morphometric measure for diagnosis and patient outcome prediction. However, segmenting CSF in non-contrast CT images is complicated by low soft tissue contrast and image noise. In this paper we propose a state-of-the-art method using a multi-scale three-dimensional (3D) fully convolutional neural network (CNN) to automatically segment all CSF within the cranial cavity. The method is trained on a small dataset comprised of four manually annotated cerebral CT images. Quantitative evaluation of a separate test dataset of four images shows a mean Dice similarity coefficient of 0.87 +/- 0.01 and mean absolute volume difference of 4.77 +/- 2.70 %. The average prediction time was 68 seconds. Our method allows for fast and fully automated 3D segmentation of cerebral CSF in non-contrast CT, and shows promising results despite a limited amount of training data.

  8. First 3D reconstruction of the rhizocephalan root system using MicroCT

    NASA Astrophysics Data System (ADS)

    Noever, Christoph; Keiler, Jonas; Glenner, Henrik

    2016-07-01

    Parasitic barnacles (Cirripedia: Rhizocephala) are highly specialized parasites of crustaceans. Instead of an alimentary tract for feeding they utilize a system of roots, which infiltrates the body of their hosts to absorb nutrients. Using X-ray micro computer tomography (MicroCT) and computer-aided 3D-reconstruction, we document the spatial organization of this root system, the interna, inside the intact host and also demonstrate its use for morphological examinations of the parasites reproductive part, the externa. This is the first 3D visualization of the unique root system of the Rhizocephala in situ, showing how it is related to the inner organs of the host. We investigated the interna from different parasitic barnacles of the family Peltogastridae, which are parasitic on anomuran crustaceans. Rhizocephalan parasites of pagurid hermit crabs and lithodid crabs were analysed in this study.

  9. Performance of an improved first generation optical CT scanner for 3D dosimetry

    NASA Astrophysics Data System (ADS)

    Qian, Xin; Adamovics, John; Wuu, Cheng-Shie

    2013-12-01

    Performance analysis of a modified 3D dosimetry optical scanner based on the first generation optical CT scanner OCTOPUS is presented. The system consists of PRESAGE™ dosimeters, the modified 3D scanner, and a new developed in-house user control panel written in Labview program which provides more flexibility to optimize mechanical control and data acquisition technique. The total scanning time has been significantly reduced from initial 8 h to ∼2 h by using the modified scanner. The functional performance of the modified scanner has been evaluated in terms of the mechanical integrity uncertainty of the data acquisition process. Optical density distribution comparison between the modified scanner, OCTOPUS and the treatment plan system has been studied. It has been demonstrated that the agreement between the modified scanner and treatment plans is comparable with that between the OCTOPUS and treatment plans.

  10. Performance of an improved first generation optical CT scanner for 3D dosimetry.

    PubMed

    Qian, Xin; Adamovics, John; Wuu, Cheng-Shie

    2013-12-21

    Performance analysis of a modified 3D dosimetry optical scanner based on the first generation optical CT scanner OCTOPUS is presented. The system consists of PRESAGE dosimeters, the modified 3D scanner, and a new developed in-house user control panel written in Labview program which provides more flexibility to optimize mechanical control and data acquisition technique. The total scanning time has been significantly reduced from initial 8 h to ∼2 h by using the modified scanner. The functional performance of the modified scanner has been evaluated in terms of the mechanical integrity uncertainty of the data acquisition process. Optical density distribution comparison between the modified scanner, OCTOPUS and the treatment plan system has been studied. It has been demonstrated that the agreement between the modified scanner and treatment plans is comparable with that between the OCTOPUS and treatment plans.

  11. 3D segmentation of lung CT data with graph-cuts: analysis of parameter sensitivities

    NASA Astrophysics Data System (ADS)

    Cha, Jung won; Dunlap, Neal; Wang, Brian; Amini, Amir

    2016-03-01

    Lung boundary image segmentation is important for many tasks including for example in development of radiation treatment plans for subjects with thoracic malignancies. In this paper, we describe a method and parameter settings for accurate 3D lung boundary segmentation based on graph-cuts from X-ray CT data1. Even though previously several researchers have used graph-cuts for image segmentation, to date, no systematic studies have been performed regarding the range of parameter that give accurate results. The energy function in the graph-cuts algorithm requires 3 suitable parameter settings: K, a large constant for assigning seed points, c, the similarity coefficient for n-links, and λ, the terminal coefficient for t-links. We analyzed the parameter sensitivity with four lung data sets from subjects with lung cancer using error metrics. Large values of K created artifacts on segmented images, and relatively much larger value of c than the value of λ influenced the balance between the boundary term and the data term in the energy function, leading to unacceptable segmentation results. For a range of parameter settings, we performed 3D image segmentation, and in each case compared the results with the expert-delineated lung boundaries. We used simple 6-neighborhood systems for n-link in 3D. The 3D image segmentation took 10 minutes for a 512x512x118 ~ 512x512x190 lung CT image volume. Our results indicate that the graph-cuts algorithm was more sensitive to the K and λ parameter settings than to the C parameter and furthermore that amongst the range of parameters tested, K=5 and λ=0.5 yielded good results.

  12. Iliosacral screw insertion using CT-3D-fluoroscopy matching navigation.

    PubMed

    Takao, Masaki; Nishii, Takashi; Sakai, Takashi; Yoshikawa, Hideki; Sugano, Nobuhiko

    2014-06-01

    Percutaneous iliosacral screw insertion requires substantial experience and detailed anatomical knowledge to find the proper entry point and trajectory even with the use of a navigation system. Our hypothesis was that three-dimensional (3D) fluoroscopic navigation combined with a preoperative computed tomography (CT)-based plan could enable surgeons to perform safe and reliable iliosacral screw insertion. The purpose of the current study is two-fold: (1) to demonstrate the navigation accuracy for sacral fractures and sacroiliac dislocations on widely displaced cadaveric pelves; and (2) to report the technical and clinical aspects of percutaneous iliosacral screw insertion using the CT-3D-fluoroscopy matching navigation system. We simulated three types of posterior pelvic ring disruptions with vertical displacements of 0, 1, 2 and 3cm using cadaveric pelvic rings. A total of six fiducial markers were fixed to the anterior surface of the sacrum. Target registration error over the sacrum was assessed with the fluoroscopic imaging centre on the second sacral vertebral body. Six patients with pelvic ring fractures underwent percutaneous iliosacral screw placement using the CT-3D-fluoroscopy matching navigation. Three pelvic ring fractures were classified as type B2 and three were classified as type C1 according to the AO-OTA classification. Iliosacral screws for the S1 and S2 vertebra were inserted. The mean target registration error over the sacrum was 1.2mm (0.5-1.9mm) in the experimental study. Fracture type and amount of vertical displacement did not affect the target registration error. All 12 screws were positioned correctly in the clinical series. There were no postoperative complications including nerve palsy. The mean deviation between the planned and the inserted screw position was 2.5mm at the screw entry point, 1.8mm at the area around the nerve root tunnels and 2.2mm at the tip of the screw. The CT-3D-fluoroscopy matching navigation system was accurate and

  13. Characterization of a parallel beam CCD optical-CT apparatus for 3D radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Krstajić, Nikola; Doran, Simon J.

    2006-12-01

    This paper describes the initial steps we have taken in establishing CCD based optical-CT as a viable alternative for 3-D radiation dosimetry. First, we compare the optical density (OD) measurements from a high quality test target and variable neutral density filter (VNDF). A modulation transfer function (MTF) of individual projections is derived for three positions of the sinusoidal test target within the scanning tank. Our CCD is then characterized in terms of its signal-to-noise ratio (SNR). Finally, a sample reconstruction of a scan of a PRESAGETM (registered trademark of Heuris Pharma, NJ, Skillman, USA.) dosimeter is given, demonstrating the capabilities of the apparatus.

  14. High precision localization of intracerebral hemorrhage based on 3D MPR on head CT images

    NASA Astrophysics Data System (ADS)

    Sun, Jianyong; Hou, Xiaoshuai; Sun, Shujie; Zhang, Jianguo

    2017-03-01

    The key step for minimally invasive intracerebral hemorrhage surgery is precisely positioning the hematoma location in the brain before and during the hematoma surgery, which can significantly improves the success rate of puncture hematoma. We designed a 3D computerized surgical plan (CSP) workstation precisely to locate brain hematoma based on Multi-Planar Reconstruction (MPR) visualization technique. We used ten patients' CT/MR studies to verify our designed CSP intracerebral hemorrhage localization method. With the doctor's assessment and comparing with the results of manual measurements, the output of CSP WS for hematoma surgery is more precise and reliable than manual procedure.

  15. Development of 3D-CT System Using MIRRORCLE-6X

    NASA Astrophysics Data System (ADS)

    Sasaki, M.; Takaku, J.; Hirai, T.; Yamada, H.

    2007-03-01

    The technique of computed tomography (CT) has been used in various fields, such as medical, non-destructive testing (NDT), baggage checking, etc. A 3D-CT system based on the portable synchrotron "MIRRORCLE"-series will be a novel instrument for these fields. The hard x-rays generated from the "MIRRORCLE" have a wide energy spectrum. Light and thin materials create absorption and refraction contrast in x-ray images by the lower energy component (< 60 keV), and heavy and thick materials create absorption contrast by the higher energy component. In addition, images with higher resolutions can be obtained using "MIRRORCLE" with a small source size of micron order. Thus, high resolution 3D-CT images of specimens containing both light and heavy materials can be obtained using "MIRRORCLE" and a 2D-detector with a wide dynamic range. In this paper, the development and output of a 3D-CT system using the "MIRRORCLE-6X" and a flat panel detector are reported. A 3D image of a piece of concrete was obtained. The detector was a flat panel detector (VARIAN, PAXSCAN2520) with 254 μm pixel size. The object and the detector were set at 50 cm and 250 cm respectively from the x-ray source, so that the magnification was 5x. The x-ray source was a 50 μm Pt rod. The rotation stage and the detector were remote-controlled using a computer, which was originally created using LabView and Visual Basic software. The exposure time was about 20 minutes. The reconstruction calculation was based on the Feldkamp algorithm, and the pixel size was 50 μm. We could observe sub-mm holes and density differences in the object. Thus, the "MIRRORCLE-CV" with 1MeV electron energy, which has same x-ray generation principles, will be an excellent x-ray source for medical diagnostics and NDT.

  16. Development of 3D-CT System Using MIRRORCLE-6X

    SciTech Connect

    Sasaki, M.; Yamada, H.; Takaku, J.; Hirai, T.

    2007-03-30

    The technique of computed tomography (CT) has been used in various fields, such as medical, non-destructive testing (NDT), baggage checking, etc. A 3D-CT system based on the portable synchrotron 'MIRRORCLE'-series will be a novel instrument for these fields. The hard x-rays generated from the 'MIRRORCLE' have a wide energy spectrum. Light and thin materials create absorption and refraction contrast in x-ray images by the lower energy component (< 60 keV), and heavy and thick materials create absorption contrast by the higher energy component. In addition, images with higher resolutions can be obtained using 'MIRRORCLE' with a small source size of micron order. Thus, high resolution 3D-CT images of specimens containing both light and heavy materials can be obtained using 'MIRRORCLE' and a 2D-detector with a wide dynamic range. In this paper, the development and output of a 3D-CT system using the 'MIRRORCLE-6X' and a flat panel detector are reported.A 3D image of a piece of concrete was obtained. The detector was a flat panel detector (VARIAN, PAXSCAN2520) with 254 {mu}m pixel size. The object and the detector were set at 50 cm and 250 cm respectively from the x-ray source, so that the magnification was 5x. The x-ray source was a 50 {mu}m Pt rod. The rotation stage and the detector were remote-controlled using a computer, which was originally created using LabView and Visual Basic software. The exposure time was about 20 minutes. The reconstruction calculation was based on the Feldkamp algorithm, and the pixel size was 50 {mu}m. We could observe sub-mm holes and density differences in the object. Thus, the 'MIRRORCLE-CV' with 1MeV electron energy, which has same x-ray generation principles, will be an excellent x-ray source for medical diagnostics and NDT.

  17. 3D patient-specific model of the tibia from CT for orthopedic use

    PubMed Central

    González-Carbonell, Raide A.; Ortiz-Prado, Armando; Jacobo-Armendáriz, Victor H.; Cisneros-Hidalgo, Yosbel A.; Alpízar-Aguirre, Armando

    2015-01-01

    Objectives 3D patient-specific model of the tibia is used to determine the torque needed to initialize the tibial torsion correction. Methods The finite elements method is used in the biomechanical modeling of tibia. The geometric model of the tibia is obtained from CT images. The tibia is modeled as an anisotropic material with non-homogeneous mechanical properties. Conclusions The maximum stress is located in the shaft of tibia diaphysis. With both meshes are obtained similar results of stresses and displacements. For this patient-specific model, the torque must be greater than 30 Nm to initialize the correction of tibial torsion deformity. PMID:25829755

  18. 3D patient-specific model of the tibia from CT for orthopedic use.

    PubMed

    González-Carbonell, Raide A; Ortiz-Prado, Armando; Jacobo-Armendáriz, Victor H; Cisneros-Hidalgo, Yosbel A; Alpízar-Aguirre, Armando

    2015-03-01

    3D patient-specific model of the tibia is used to determine the torque needed to initialize the tibial torsion correction. The finite elements method is used in the biomechanical modeling of tibia. The geometric model of the tibia is obtained from CT images. The tibia is modeled as an anisotropic material with non-homogeneous mechanical properties. The maximum stress is located in the shaft of tibia diaphysis. With both meshes are obtained similar results of stresses and displacements. For this patient-specific model, the torque must be greater than 30 Nm to initialize the correction of tibial torsion deformity.

  19. CT Colonography (Virtual Colonoscopy)

    MedlinePlus

    ... ray beam follows a spiral path. A special computer program processes this large volume of data to create ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ...

  20. Effect of voxel size on the accuracy of 3D reconstructions with cone beam CT

    PubMed Central

    Maret, D; Telmon, N; Peters, O A; Lepage, B; Treil, J; Inglèse, J M; Peyre, A; Kahn, J L; Sixou, M

    2012-01-01

    Objectives The various types of cone beam CT (CBCT) differ in several technical characteristics, notably their spatial resolution, which is defined by the acquisition voxel size. However, data are still lacking on the effects of voxel size on the metric accuracy of three-dimensional (3D) reconstructions. This study was designed to assess the effect of isotropic voxel size on the 3D reconstruction accuracy and reproducibility of CBCT data. Methods The study sample comprised 70 teeth (from the Institut d’Anatomie Normale, Strasbourg, France). The teeth were scanned with a KODAK 9500 3D® CBCT (Carestream Health, Inc., Marne-la-Vallée, France), which has two voxel sizes: 200 µm (CBCT 200 µm group) and 300 µm (CBCT 300 µm group). These teeth had also been scanned with the KODAK 9000 3D® CBCT (Carestream Health, Inc.) (CBCT 76 µm group) and the SCANCO Medical micro-CT XtremeCT (SCANCO Medical, Brüttisellen, Switzerland) (micro-CT 41 µm group) considered as references. After semi-automatic segmentation with AMIRA® software (Visualization Sciences Group, Burlington, MA), tooth volumetric measurements were obtained. Results The Bland–Altman method showed no difference in tooth volumes despite a slight underestimation for the CBCT 200 µm and 300 µm groups compared with the two reference groups. The underestimation was statistically significant for the volumetric measurements of the CBCT 300 µm group relative to the two reference groups (Passing–Bablok method). Conclusions CBCT is not only a tool that helps in diagnosis and detection but it has the complementary advantage of being a measuring instrument, the accuracy of which appears connected to the size of the voxels. Future applications of such measurements with CBCT are discussed. PMID:23166362

  1. Effect of voxel size on the accuracy of 3D reconstructions with cone beam CT.

    PubMed

    Maret, D; Telmon, N; Peters, O A; Lepage, B; Treil, J; Inglèse, J M; Peyre, A; Kahn, J L; Sixou, M

    2012-12-01

    The various types of cone beam CT (CBCT) differ in several technical characteristics, notably their spatial resolution, which is defined by the acquisition voxel size. However, data are still lacking on the effects of voxel size on the metric accuracy of three-dimensional (3D) reconstructions. This study was designed to assess the effect of isotropic voxel size on the 3D reconstruction accuracy and reproducibility of CBCT data. The study sample comprised 70 teeth (from the Institut d'Anatomie Normale, Strasbourg, France). The teeth were scanned with a KODAK 9500 3D® CBCT (Carestream Health, Inc., Marne-la-Vallée, France), which has two voxel sizes: 200 µm (CBCT 200 µm group) and 300 µm (CBCT 300 µm group). These teeth had also been scanned with the KODAK 9000 3D® CBCT (Carestream Health, Inc.) (CBCT 76 µm group) and the SCANCO Medical micro-CT XtremeCT (SCANCO Medical, Brüttisellen, Switzerland) (micro-CT 41 µm group) considered as references. After semi-automatic segmentation with AMIRA® software (Visualization Sciences Group, Burlington, MA), tooth volumetric measurements were obtained. The Bland-Altman method showed no difference in tooth volumes despite a slight underestimation for the CBCT 200 µm and 300 µm groups compared with the two reference groups. The underestimation was statistically significant for the volumetric measurements of the CBCT 300 µm group relative to the two reference groups (Passing-Bablok method). CBCT is not only a tool that helps in diagnosis and detection but it has the complementary advantage of being a measuring instrument, the accuracy of which appears connected to the size of the voxels. Future applications of such measurements with CBCT are discussed.

  2. 3D iterative full and half scan reconstruction in CT architectures with distributed sources

    NASA Astrophysics Data System (ADS)

    Iatrou, M.; De Man, B.; Beque, D.; Yin, Z.; Khare, K.; Benson, T. M.

    2008-03-01

    In 3 rd generation CT systems projection data, generated by X-rays emitted from a single source and passing through the imaged object, are acquired by a single detector covering the entire field of view (FOV). Novel CT system architectures employing distributed sources [1,2] could extend the axial coverage, while removing cone-beam artifacts and improving spatial resolution and dose. The sources can be distributed in plane and/or in the longitudinal direction. We investigate statistical iterative reconstruction of multi-axial data, acquired with simulated CT systems with multiple sources distributed along the in-plane and longitudinal directions. The current study explores the feasibility of 3D iterative Full and Half Scan reconstruction methods for CT systems with two different architectures. In the first architecture the sources are distributed in the longitudinal direction, and in the second architecture the sources are distributed both longitudinally and trans-axially. We used Penalized Weighted Least Squares Transmission Reconstruction (PWLSTR) and incorporated a projector-backprojector model matching the simulated architectures. The proposed approaches minimize artifacts related to the proposed geometries. The reconstructed images show that the investigated architectures can achieve good image quality for very large coverage without severe cone-beam artifacts.

  3. 3D cardiac motion reconstruction from CT data and tagged MRI.

    PubMed

    Wang, Xiaoxu; Mihalef, Viorel; Qian, Zhen; Voros, Szilard; Metaxas, Dimitris

    2012-01-01

    In this paper we present a novel method for left ventricle (LV) endocardium motion reconstruction using high resolution CT data and tagged MRI. High resolution CT data provide anatomic details on the LV endocardial surface, such as the papillary muscle and trabeculae carneae. Tagged MRI provides better time resolution. The combination of these two imaging techniques can give us better understanding on left ventricle motion. The high resolution CT images are segmented with mean shift method and generate the LV endocardium mesh. The meshless deformable model built with high resolution endocardium surface from CT data fit to the tagged MRI of the same phase. 3D deformation of the myocardium is computed with the Lagrangian dynamics and local Laplacian deformation. The segmented inner surface of left ventricle is compared with the heart inner surface picture and show high agreement. The papillary muscles are attached to the inner surface with roots. The free wall of the left ventricle inner surface is covered with trabeculae carneae. The deformation of the heart wall and the papillary muscle in the first half of the cardiac cycle is presented. The motion reconstruction results are very close to the live heart video.

  4. A comprehensive evaluation of the PRESAGE/optical-CT 3D dosimetry system

    SciTech Connect

    Sakhalkar, H. S.; Adamovics, J.; Ibbott, G.; Oldham, M.

    2009-01-15

    This work presents extensive investigations to evaluate the robustness (intradosimeter consistency and temporal stability of response), reproducibility, precision, and accuracy of a relatively new 3D dosimetry system comprising a leuco-dye doped plastic 3D dosimeter (PRESAGE) and a commercial optical-CT scanner (OCTOPUS 5x scanner from MGS Research, Inc). Four identical PRESAGE 3D dosimeters were created such that they were compatible with the Radiologic Physics Center (RPC) head-and-neck (H and N) IMRT credentialing phantom. Each dosimeter was irradiated with a rotationally symmetric arrangement of nine identical small fields (1x3 cm{sup 2}) impinging on the flat circular face of the dosimeter. A repetitious sequence of three dose levels (4, 2.88, and 1.28 Gy) was delivered. The rotationally symmetric treatment resulted in a dose distribution with high spatial variation in axial planes but only gradual variation with depth along the long axis of the dosimeter. The significance of this treatment was that it facilitated accurate film dosimetry in the axial plane, for independent verification. Also, it enabled rigorous evaluation of robustness, reproducibility and accuracy of response, at the three dose levels. The OCTOPUS 5x commercial scanner was used for dose readout from the dosimeters at daily time intervals. The use of improved optics and acquisition technique yielded substantially improved noise characteristics (reduced to {approx}2%) than has been achieved previously. Intradosimeter uniformity of radiochromic response was evaluated by calculating a 3D gamma comparison between each dosimeter and axially rotated copies of the same dosimeter. This convenient technique exploits the rotational symmetry of the distribution. All points in the gamma comparison passed a 2% difference, 1 mm distance-to-agreement criteria indicating excellent intradosimeter uniformity even at low dose levels. Postirradiation, the dosimeters were all found to exhibit a slight increase in

  5. A comprehensive evaluation of the PRESAGE/optical-CT 3D dosimetry system.

    PubMed

    Sakhalkar, H S; Adamovics, J; Ibbott, G; Oldham, M

    2009-01-01

    This work presents extensive investigations to evaluate the robustness (intradosimeter consistency and temporal stability of response), reproducibility, precision, and accuracy of a relatively new 3D dosimetry system comprising a leuco-dye doped plastic 3D dosimeter (PRESAGE) and a commercial optical-CT scanner (OCTOPUS 5x scanner from MGS Research, Inc). Four identical PRESAGE 3D dosimeters were created such that they were compatible with the Radiologic Physics Center (RPC) head-and-neck (H&N) IMRT credentialing phantom. Each dosimeter was irradiated with a rotationally symmetric arrangement of nine identical small fields (1 x 3 cm2) impinging on the flat circular face of the dosimeter. A repetitious sequence of three dose levels (4, 2.88, and 1.28 Gy) was delivered. The rotationally symmetric treatment resulted in a dose distribution with high spatial variation in axial planes but only gradual variation with depth along the long axis of the dosimeter. The significance of this treatment was that it facilitated accurate film dosimetry in the axial plane, for independent verification. Also, it enabled rigorous evaluation of robustness, reproducibility and accuracy of response, at the three dose levels. The OCTOPUS 5x commercial scanner was used for dose readout from the dosimeters at daily time intervals. The use of improved optics and acquisition technique yielded substantially improved noise characteristics (reduced to approximately 2%) than has been achieved previously. Intradosimeter uniformity of radiochromic response was evaluated by calculating a 3D gamma comparison between each dosimeter and axially rotated copies of the same dosimeter. This convenient technique exploits the rotational symmetry of the distribution. All points in the gamma comparison passed a 2% difference, 1 mm distance-to-agreement criteria indicating excellent intradosimeter uniformity even at low dose levels. Postirradiation, the dosimeters were all found to exhibit a slight increase in

  6. Reconstruction of 4D-CT from a Single Free-Breathing 3D-CT by Spatial-Temporal Image Registration

    PubMed Central

    Wu, Guorong; Wang, Qian; Lian, Jun; Shen, Dinggang

    2011-01-01

    In the radiation therapy of lung cancer, a free-breathing 3D-CT image is usually acquired in the treatment day for image-guided patient setup, by registering with the free-breathing 3D-CT image acquired in the planning day. In this way, the optimal dose plan computed in the planning day can be transferred onto the treatment day for cancer radiotherapy. However, patient setup based on the simple registration of the free-breathing 3D-CT images of the planning and the treatment days may mislead the radiotherapy, since the free-breathing 3D-CT is actually the mixed-phase image, with different slices often acquired from different respiratory phases. Moreover, a 4D-CT that is generally acquired in the planning day for improvement of dose planning is often ignored for guiding patient setup in the treatment day. To overcome these limitations, we present a novel two-step method to reconstruct the 4D-CT from a single free-breathing 3D-CT of the treatment day, by utilizing the 4D-CT model built in the planning day. Specifically, in the first step, we proposed a new spatial-temporal registration algorithm to align all phase images of the 4D-CT acquired in the planning day, for building a 4D-CT model with temporal correspondences established among all respiratory phases. In the second step, we first determine the optimal phase for each slice of the free-breathing (mixed-phase) 3D-CT of the treatment day by comparing with the 4D-CT of the planning day and thus obtain a sequence of partial 3D-CT images for the treatment day, each with only the incomplete image information in certain slices; and then we reconstruct a complete 4D-CT for the treatment day by warping the 4D-CT of the planning day (with complete information) to the sequence of partial 3D-CT images of the treatment day, under the guidance of the 4D-CT model built in the planning day. We have comprehensively evaluated our 4D-CT model building algorithm on a public lung image database, achieving the best registration

  7. Acceleration of EM-Based 3D CT Reconstruction Using FPGA.

    PubMed

    Choi, Young-Kyu; Cong, Jason

    2016-06-01

    Reducing radiation doses is one of the key concerns in computed tomography (CT) based 3D reconstruction. Although iterative methods such as the expectation maximization (EM) algorithm can be used to address this issue, applying this algorithm to practice is difficult due to the long execution time. Our goal is to decrease this long execution time to an order of a few minutes, so that low-dose 3D reconstruction can be performed even in time-critical events. In this paper we introduce a novel parallel scheme that takes advantage of numerous block RAMs on field-programmable gate arrays (FPGAs). Also, an external memory bandwidth reduction strategy is presented to reuse both the sinogram and the voxel intensity. Moreover, a customized processing engine based on the FPGA is presented to increase overall throughput while reducing the logic consumption. Finally, a hardware and software flow is proposed to quickly construct a design for various CT machines. The complete reconstruction system is implemented on an FPGA-based server-class node. Experiments on actual patient data show that a 26.9 × speedup can be achieved over a 16-thread multicore CPU implementation.

  8. 3D segmentation of the true and false lumens on CT aortic dissection images

    NASA Astrophysics Data System (ADS)

    Fetnaci, Nawel; Łubniewski, Paweł; Miguel, Bruno; Lohou, Christophe

    2013-03-01

    Our works are related to aortic dissections which are a medical emergency and can quickly lead to death. In this paper, we want to retrieve in CT images the false and the true lumens which are aortic dissection features. Our aim is to provide a 3D view of the lumens that we can difficultly obtain either by volume rendering or by another visualization tool which only directly gives the outer contour of the aorta; or by other segmentation methods because they mainly directly segment either only the outer contour of the aorta or other connected arteries and organs both. In our work, we need to segment the two lumens separately; this segmentation will allow us to: distinguish them automatically, facilitate the landing of the aortic prosthesis, propose a virtual 3d navigation and do quantitative analysis. We chose to segment these data by using a deformable model based on the fast marching method. In the classical fast marching approach, a speed function is used to control the front propagation of a deforming curve. The speed function is only based on the image gradient. In our CT images, due to the low resolution, with the fast marching the front propagates from a lumen to the other; therefore, the gradient data is insufficient to have accurate segmentation results. In the paper, we have adapted the fast marching method more particularly by modifying the speed function and we succeed in segmenting the two lumens separately.

  9. Feature extraction, analysis, and 3D visualization of local lung regions in volumetric CT images

    NASA Astrophysics Data System (ADS)

    Delegacz, Andrzej; Lo, Shih-Chung B.; Freedman, Matthew T.; Mun, Seong K.

    2001-05-01

    The purpose of the work was to develop image functions for volumetric segmentation, feature extraction, and enhanced 3D visualization of local regions using CT datasets of human lungs. The system is aimed to assist the radiologist in the analysis of lung nodules. Volumetric datasets consisting of 30-50 thoracic helical low-dose CT slices were used in the study. The 3D topological characteristics of local structures including bronchi, blood vessels, and nodules were computed and evaluated. When a location of a region of interest is identified, the computer would automatically compute size, surface of the area, and normalized shape index of the suspected lesion. The developed system can also allow the user to perform interactive operation for evaluation of lung regions and structures through a user- friendly interface. These functions provide the user with a powerful tool to observe and investigate clinically interesting regions through unconventional radiographic viewings and analyses. The developed functions can also be used to view and analyze patient's lung abnormalities in surgical planning applications. Additionally, we see the possibility of using the system as a teaching tool for correlating anatomy of lungs.

  10. Description of patellar movement by 3D parameters obtained from dynamic CT acquisition

    NASA Astrophysics Data System (ADS)

    de Sá Rebelo, Marina; Moreno, Ramon Alfredo; Gobbi, Riccardo Gomes; Camanho, Gilberto Luis; de Ávila, Luiz Francisco Rodrigues; Demange, Marco Kawamura; Pecora, Jose Ricardo; Gutierrez, Marco Antonio

    2014-03-01

    The patellofemoral joint is critical in the biomechanics of the knee. The patellofemoral instability is one condition that generates pain, functional impairment and often requires surgery as part of orthopedic treatment. The analysis of the patellofemoral dynamics has been performed by several medical image modalities. The clinical parameters assessed are mainly based on 2D measurements, such as the patellar tilt angle and the lateral shift among others. Besides, the acquisition protocols are mostly performed with the leg laid static at fixed angles. The use of helical multi slice CT scanner can allow the capture and display of the joint's movement performed actively by the patient. However, the orthopedic applications of this scanner have not yet been standardized or widespread. In this work we present a method to evaluate the biomechanics of the patellofemoral joint during active contraction using multi slice CT images. This approach can greatly improve the analysis of patellar instability by displaying the physiology during muscle contraction. The movement was evaluated by computing its 3D displacements and rotations from different knee angles. The first processing step registered the images in both angles based on the femuŕs position. The transformation matrix of the patella from the images was then calculated, which provided the rotations and translations performed by the patella from its position in the first image to its position in the second image. Analysis of these parameters for all frames provided real 3D information about the patellar displacement.

  11. 3D Forward and Back-Projection for X-Ray CT Using Separable Footprints

    PubMed Central

    Long, Yong; Fessler, Jeffrey A.; Balter, James M.

    2010-01-01

    Iterative methods for 3D image reconstruction have the potential to improve image quality over conventional filtered back projection (FBP) in X-ray computed tomography (CT). However, the computation burden of 3D cone-beam forward and back-projectors is one of the greatest challenges facing practical adoption of iterative methods for X-ray CT. Moreover, projector accuracy is also important for iterative methods. This paper describes two new separable footprint (SF) projector methods that approximate the voxel footprint functions as 2D separable functions. Because of the separability of these footprint functions, calculating their integrals over a detector cell is greatly simplified and can be implemented efficiently. The SF-TR projector uses trapezoid functions in the transaxial direction and rectangular functions in the axial direction, whereas the SF-TT projector uses trapezoid functions in both directions. Simulations and experiments showed that both SF projector methods are more accurate than the distance-driven (DD) projector, which is a current state-of-the-art method in the field. The SF-TT projector is more accurate than the SF-TR projector for rays associated with large cone angles. The SF-TR projector has similar computation speed with the DD projector and the SF-TT projector is about two times slower. PMID:20529732

  12. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy.

    PubMed

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-21

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  13. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy

    NASA Astrophysics Data System (ADS)

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-01

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  14. CT-based 3-D visualisation of secure bone corridors and optimal trajectories for sacroiliac screws.

    PubMed

    Mendel, Thomas; Radetzki, Florian; Wohlrab, David; Stock, Karsten; Hofmann, Gunther Olaf; Noser, Hansrudi

    2013-07-01

    Sacroiliac screw (SI) fixation represents the only minimally invasive method to stabilise unstable injuries of the posterior pelvic ring. However, it is technically demanding. The narrow sacral proportions and a high inter-individual shape variability places adjacent neurovascular structures at potential risk. In this study a CT-based virtual analysis of the iliosacral anatomy in the human pelvis was performed to visualise and analyse 3-D bone corridors for the safe placement of SI-screws in the first sacral segment. Computer-aided calculation of 3-D transverse and general SI-corridors as a sum of all inner-bony 7.3-mm screw positions was done with custom-made software algorithms based on CT-scans of intact human pelvises. Radiomorphometric analysis of 11 CT-DICOM datasets using the software Amira 4.2. Optimal screw tracks allowing the greatest safety distance to the cortex were computed. Corridor geometry and optimal tracks were visualised; measurement data were calculated. A transverse corridor existed in 10 pelvises. In one dysmorphic pelvis, the pedicular height at the level of the 1st neural foramina came below the critical distance of 7.3mm defined by the outer screw diameter. The mean corridor volume was 45.2 cm3, with a length of 14.9cm. The oval cross-section measured 2.8 cm2. The diameter of the optimal screw pathway with the greatest safety distance was 14.2mm. A double cone-shaped general corridor for screw penetration up to the centre of the S1-body was calculated bilaterally for every pelvis. The mean volume was 120.6 cm3 for the left side and 115.8 cm3 for the right side. The iliac entry area measured 49.1 versus 46.0 cm2. Optimal screw tracks were calculated in terms of projected inlet and outlet angles. Multiple optimal screw positions existed for each pelvis. The described method allows an automated 3-D analysis with regard to secure SI-screw corridors even with a high number of CT-datasets. Corridor visualisation and calculation of optimal screw

  15. Semi-automatic 3D segmentation of costal cartilage in CT data from Pectus Excavatum patients

    NASA Astrophysics Data System (ADS)

    Barbosa, Daniel; Queirós, Sandro; Rodrigues, Nuno; Correia-Pinto, Jorge; Vilaça, J.

    2015-03-01

    One of the current frontiers in the clinical management of Pectus Excavatum (PE) patients is the prediction of the surgical outcome prior to the intervention. This can be done through computerized simulation of the Nuss procedure, which requires an anatomically correct representation of the costal cartilage. To this end, we take advantage of the costal cartilage tubular structure to detect it through multi-scale vesselness filtering. This information is then used in an interactive 2D initialization procedure which uses anatomical maximum intensity projections of 3D vesselness feature images to efficiently initialize the 3D segmentation process. We identify the cartilage tissue centerlines in these projected 2D images using a livewire approach. We finally refine the 3D cartilage surface through region-based sparse field level-sets. We have tested the proposed algorithm in 6 noncontrast CT datasets from PE patients. A good segmentation performance was found against reference manual contouring, with an average Dice coefficient of 0.75±0.04 and an average mean surface distance of 1.69+/-0.30mm. The proposed method requires roughly 1 minute for the interactive initialization step, which can positively contribute to an extended use of this tool in clinical practice, since current manual delineation of the costal cartilage can take up to an hour.

  16. Micro-CT images reconstruction and 3D visualization for small animal studying

    NASA Astrophysics Data System (ADS)

    Gong, Hui; Liu, Qian; Zhong, Aijun; Ju, Shan; Fang, Quan; Fang, Zheng

    2005-01-01

    A small-animal x-ray micro computed tomography (micro-CT) system has been constructed to screen laboratory small animals and organs. The micro-CT system consists of dual fiber-optic taper-coupled CCD detectors with a field-of-view of 25x50 mm2, a microfocus x-ray source, a rotational subject holder. For accurate localization of rotation center, coincidence between the axis of rotation and centre of image was studied by calibration with a polymethylmethacrylate cylinder. Feldkamp"s filtered back-projection cone-beam algorithm is adopted for three-dimensional reconstruction on account of the effective corn-beam angle is 5.67° of the micro-CT system. 200x1024x1024 matrix data of micro-CT is obtained with the magnification of 1.77 and pixel size of 31x31μm2. In our reconstruction software, output image size of micro-CT slices data, magnification factor and rotation sample degree can be modified in the condition of different computational efficiency and reconstruction region. The reconstructed image matrix data is processed and visualization by Visualization Toolkit (VTK). Data parallelism of VTK is performed in surface rendering of reconstructed data in order to improve computing speed. Computing time of processing a 512x512x512 matrix datasets is about 1/20 compared with serial program when 30 CPU is used. The voxel size is 54x54x108 μm3. The reconstruction and 3-D visualization images of laboratory rat ear are presented.

  17. Improvement of image quality and dose management in CT fluoroscopy by iterative 3D image reconstruction.

    PubMed

    Grosser, Oliver S; Wybranski, Christian; Kupitz, Dennis; Powerski, Maciej; Mohnike, Konrad; Pech, Maciej; Amthauer, Holger; Ricke, Jens

    2017-09-01

    The objective of this study was to assess the influence of an iterative CT reconstruction algorithm (IA), newly available for CT-fluoroscopy (CTF), on image noise, readers' confidence and effective dose compared to filtered back projection (FBP). Data from 165 patients (FBP/IA = 82/74) with CTF in the thorax, abdomen and pelvis were included. Noise was analysed in a large-diameter vessel. The impact of reconstruction and variables (e.g. X-ray tube current I) influencing noise and effective dose were analysed by ANOVA and a pairwise t-test with Bonferroni-Holm correction. Noise and readers' confidence were evaluated by three readers. Noise was significantly influenced by reconstruction, I, body region and circumference (all p ≤ 0.0002). IA reduced the noise significantly compared to FBP (p = 0.02). The effect varied for body regions and circumferences (p ≤ 0.001). The effective dose was influenced by the reconstruction, body region, interventional procedure and I (all p ≤ 0.02). The inter-rater reliability for noise and readers' confidence was good (W ≥ 0.75, p < 0.0001). Noise and readers' confidence were significantly better in AIDR-3D compared to FBP (p ≤ 0.03). Generally, IA yielded a significant reduction of the median effective dose. The CTF reconstruction by IA showed a significant reduction in noise and effective dose while readers' confidence increased. • CTF is performed for image guidance in interventional radiology. • Patient exposure was estimated from DLP documented by the CT. • Iterative CT reconstruction is appropriate to reduce image noise in CTF. • Using iterative CT reconstruction, the effective dose was significantly reduced in abdominal interventions.

  18. Automatic 3D pulmonary nodule detection in CT images: A survey.

    PubMed

    Valente, Igor Rafael S; Cortez, Paulo César; Neto, Edson Cavalcanti; Soares, José Marques; de Albuquerque, Victor Hugo C; Tavares, João Manuel R S

    2016-02-01

    This work presents a systematic review of techniques for the 3D automatic detection of pulmonary nodules in computerized-tomography (CT) images. Its main goals are to analyze the latest technology being used for the development of computational diagnostic tools to assist in the acquisition, storage and, mainly, processing and analysis of the biomedical data. Also, this work identifies the progress made, so far, evaluates the challenges to be overcome and provides an analysis of future prospects. As far as the authors know, this is the first time that a review is devoted exclusively to automated 3D techniques for the detection of pulmonary nodules from lung CT images, which makes this work of noteworthy value. The research covered the published works in the Web of Science, PubMed, Science Direct and IEEEXplore up to December 2014. Each work found that referred to automated 3D segmentation of the lungs was individually analyzed to identify its objective, methodology and results. Based on the analysis of the selected works, several studies were seen to be useful for the construction of medical diagnostic aid tools. However, there are certain aspects that still require attention such as increasing algorithm sensitivity, reducing the number of false positives, improving and optimizing the algorithm detection of different kinds of nodules with different sizes and shapes and, finally, the ability to integrate with the Electronic Medical Record Systems and Picture Archiving and Communication Systems. Based on this analysis, we can say that further research is needed to develop current techniques and that new algorithms are needed to overcome the identified drawbacks. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  19. Prognostic value of Tissue Transition Projection 3D transparent wall CT reconstructions in bowel ischemia.

    PubMed

    Moschetta, Marco; Scardapane, Arnaldo; Telegrafo, Michele; Lucarelli, Nicola Maria; Lorusso, Valentina; Angelelli, Giuseppe; Stabile Ianora, Amato Antonio

    2016-10-01

    Multi-detector computed tomography (MDCT) represents the gold standard in patients with acute abdomen syndrome and suspected bowel ischemia. It provides a correct diagnosis and contributes to appropriate treatment planning. This study aims to evaluate the role of 3D Tissue Transition Projection (TTP) transparent wall CT reconstruction for detecting the degree of bowel dilatation and to correlate this finding with the aetiology and prognosis in patients affected by mesenteric infarction. Forty-seven patients affected by bowel infarction due to vascular obstruction (arterial in 66% of cases, venous in 34%) were assessed by MDCT examination searching for the degree of bowel dilatation (subdivided into 4 groups: entire small bowel (SB); ≥50% of SB; < 50% of SB; large bowel only). Two blinded radiologists evaluated TTP 3D transparent wall and multi-planar reconstructions. Chi square test was used to correlate CT findings with the disease course and the mortality rate. Cohen's kappa statistics was used in order to assess inter-observer agreement. The overall mortality rate was 64%, with a 90% value for arterial forms and 10% in case of venous infarctions. The entire SB (n = 10) or a ≥50% SB dilatation (n = 16) correlated with poor prognosis in all cases (p < 0.05); a <50% SB dilatation (n = 16) correlated with good prognosis in 87.5% of cases (p < 0.05). A large bowel only dilatation (n = 5) did not show a significant prognostic value (p = 0.13). Almost perfect agreement between the two readers was found (k = 0.84). MDCT offers different reconstruction software for diagnosing bowel ischemia. 3D TTP transparent wall reconstructions represent a rapid and automatic tool for identifying loop dilatation, which significantly correlates with an arterial aetiology and poor prognosis. Copyright © 2016. Published by Elsevier Ltd.

  20. Technical note: cone beam CT imaging for 3D image guided brachytherapy for gynecological HDR brachytherapy.

    PubMed

    Reniers, Brigitte; Verhaegen, Frank

    2011-05-01

    This paper focuses on a novel image guidance technique for gynecological brachytherapy treatment. The present standard technique is orthogonal x-ray imaging to reconstruct the 3D position of the applicator when the availability of CT or MR is limited. Our purpose is to introduce 3D planning in the brachytherapy suite using a cone beam CT (CBCT) scanner dedicated to brachytherapy. This would avoid moving the patient between imaging and treatment procedures which may cause applicator motion. This could be used to replace the x-ray images or to verify the treatment position immediately prior to dose delivery. The sources of CBCT imaging artifacts in the case of brachytherapy were identified and removed where possible. The image quality was further improved by modifying the x-ray tube voltage, modifying the compensator bowtie filter and optimizing technical parameters such as the detector gain or tube current. The image quality was adequate to reconstruct the applicators in the treatment planning system. The position of points A and the localization of the organs at risk (OAR) ICRU points is easily achieved. This allows identification of cases where the rectum had moved with respect to the ICRU point which would require asymmetrical source loading. A better visualization is a first step toward a better sparing of the OAR. Treatment planning for gynecological brachytherapy is aided by CBCT images. CBCT presents advantages over CT: acquisition in the treatment room and in the treatment position due to the larger clearance of the CBCT, thereby reducing problems associated to moving patients between rooms.

  1. Automatic seed picking for brachytherapy postimplant validation with 3D CT images.

    PubMed

    Zhang, Guobin; Sun, Qiyuan; Jiang, Shan; Yang, Zhiyong; Ma, Xiaodong; Jiang, Haisong

    2017-06-22

    Postimplant validation is an indispensable part in the brachytherapy technique. It provides the necessary feedback to ensure the quality of operation. The ability to pick implanted seed relates directly to the accuracy of validation. To address it, an automatic approach is proposed for picking implanted brachytherapy seeds in 3D CT images. In order to pick seed configuration (location and orientation) efficiently, the approach starts with the segmentation of seed from CT images using a thresholding filter which based on gray-level histogram. Through the process of filtering and denoising, the touching seed and single seed are classified. The true novelty of this approach is found in the application of the canny edge detection and improved concave points matching algorithm to separate touching seeds. Through the computation of image moments, the seed configuration can be determined efficiently. Finally, two different experiments are designed to verify the performance of the proposed approach: (1) physical phantom with 60 model seeds, and (2) patient data with 16 cases. Through assessment of validated results by a medical physicist, the proposed method exhibited promising results. Experiment on phantom demonstrates that the error of seed location and orientation is within ([Formula: see text]) mm and ([Formula: see text])[Formula: see text], respectively. In addition, the most seed location and orientation error is controlled within 0.8 mm and 3.5[Formula: see text] in all cases, respectively. The average process time of seed picking is 8.7 s per 100 seeds. In this paper, an automatic, efficient and robust approach, performed on CT images, is proposed to determine the implanted seed location as well as orientation in a 3D workspace. Through the experiments with phantom and patient data, this approach also successfully exhibits good performance.

  2. Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid

    PubMed Central

    Bache, Steven; Malcolm, Javian; Adamovics, John; Oldham, Mark

    2016-01-01

    Telecentric optical computed tomography (optical-CT) is a state-of-the-art method for visualizing and quantifying 3-dimensional dose distributions in radiochromic dosimeters. In this work a prototype telecentric system (DFOS—Duke Fresnel Optical-CT Scanner) is evaluated which incorporates two substantial design changes: the use of Fresnel lenses (reducing lens costs from $10-30K t0 $1-3K) and the use of a ‘solid tank’ (which reduces noise, and the volume of refractively matched fluid from 1ltr to 10cc). The efficacy of DFOS was evaluated by direct comparison against commissioned scanners in our lab. Measured dose distributions from all systems were compared against the predicted dose distributions from a commissioned treatment planning system (TPS). Three treatment plans were investigated including a simple four-field box treatment, a multiple small field delivery, and a complex IMRT treatment. Dosimeters were imaged within 2h post irradiation, using consistent scanning techniques (360 projections acquired at 1 degree intervals, reconstruction at 2mm). DFOS efficacy was evaluated through inspection of dose line-profiles, and 2D and 3D dose and gamma maps. DFOS/TPS gamma pass rates with 3%/3mm dose difference/distance-to-agreement criteria ranged from 89.3% to 92.2%, compared to from 95.6% to 99.0% obtained with the commissioned system. The 3D gamma pass rate between the commissioned system and DFOS was 98.2%. The typical noise rates in DFOS reconstructions were up to 3%, compared to under 2% for the commissioned system. In conclusion, while the introduction of a solid tank proved advantageous with regards to cost and convenience, further work is required to improve the image quality and dose reconstruction accuracy of the new DFOS optical-CT system. PMID:27019460

  3. Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid.

    PubMed

    Bache, Steven; Malcolm, Javian; Adamovics, John; Oldham, Mark

    2016-01-01

    Telecentric optical computed tomography (optical-CT) is a state-of-the-art method for visualizing and quantifying 3-dimensional dose distributions in radiochromic dosimeters. In this work a prototype telecentric system (DFOS-Duke Fresnel Optical-CT Scanner) is evaluated which incorporates two substantial design changes: the use of Fresnel lenses (reducing lens costs from $10-30K t0 $1-3K) and the use of a 'solid tank' (which reduces noise, and the volume of refractively matched fluid from 1 ltr to 10 cc). The efficacy of DFOS was evaluated by direct comparison against commissioned scanners in our lab. Measured dose distributions from all systems were compared against the predicted dose distributions from a commissioned treatment planning system (TPS). Three treatment plans were investigated including a simple four-field box treatment, a multiple small field delivery, and a complex IMRT treatment. Dosimeters were imaged within 2 h post irradiation, using consistent scanning techniques (360 projections acquired at 1 degree intervals, reconstruction at 2mm). DFOS efficacy was evaluated through inspection of dose line-profiles, and 2D and 3D dose and gamma maps. DFOS/TPS gamma pass rates with 3%/3mm dose difference/distance-to-agreement criteria ranged from 89.3% to 92.2%, compared to from 95.6% to 99.0% obtained with the commissioned system. The 3D gamma pass rate between the commissioned system and DFOS was 98.2%. The typical noise rates in DFOS reconstructions were up to 3%, compared to under 2% for the commissioned system. In conclusion, while the introduction of a solid tank proved advantageous with regards to cost and convenience, further work is required to improve the image quality and dose reconstruction accuracy of the new DFOS optical-CT system.

  4. A 3-D CT Analysis of Screw and Suture-Button Fixation of the Syndesmosis.

    PubMed

    Schon, Jason M; Williams, Brady T; Venderley, Melanie B; Dornan, Grant J; Backus, Jonathon D; Turnbull, Travis Lee; LaPrade, Robert F; Clanton, Thomas O

    2017-02-01

    Historically, syndesmosis injuries have been repaired with screw fixation; however, some suggest that suture-button constructs may provide a more accurate anatomic and physiologic reduction. The purpose of this study was to compare changes in the volume of the syndesmotic space following screw or suture-button fixation using a preinjury and postoperative 3-D computed tomography (CT) model. The null hypothesis was that no difference would be observed among repair techniques. Twelve pairs of cadaveric specimens were dissected to identify the syndesmotic ligaments. Specimens were imaged with CT prior to the creation of a complete syndesmosis injury and were subsequently repaired using 1 of 3 randomly assigned techniques: (a) one 3.5-mm cortical screw, (b) 1 suture-button, and (c) 2 suture-buttons. Specimens were imaged postoperatively with CT. 3-D models of all scans and tibiofibular joint space volumes were calculated to assess restoration of the native syndesmosis. Analysis of variance and Tukey's method were used to compare least squares mean differences from the intact syndesmosis among repair techniques. For each of the 3 fixation methods, the total postoperative syndesmosis volume was significantly decreased relative to the intact state. The total mean decreases in volume compared with the intact state for the 1-suture-button construct, 2-suture-button construct, and syndesmotic screw were -561 mm(3) (95% CI, -878 to -244), -964 mm(3) (95% CI, -1281 to -647) and -377 mm(3) (95% CI, -694 to -60), respectively. All repairs notably reduced the volume of the syndesmosis beyond the intact state. Fixation with 1 suture-button was not significantly different from screw or 2-suture-button fixation; however, fixation with 2 suture-buttons resulted in significantly decreased volume compared with screw fixation. The results of this study suggest that the 1-suture-button repair technique and the screw fixation repair technique were comparable for reduction of syndesmosis

  5. The relationship between post-traumatic ossicular injuries and conductive hearing loss: A 3D-CT study.

    PubMed

    Maillot, Olivier; Attyé, Arnaud; Boutet, Claire; Boubagra, Kamel; Perolat, Romain; Zanolla, Marion; Grand, Sylvie; Schmerber, Sébastien; Krainik, Alexandre

    2017-09-01

    After a trauma, the conductive ossicular chain may be disrupted by ossicular luxation or fracture. Recent developments in 3D-CT allow a better understanding of ossicular injuries. In this retrospective study, we compared patients with post-traumatic conductive hearing loss (CHL) with those referred without CHL to evaluate the relationship between ossicular injuries and CHL. We also assessed the added value of 3D reconstructions on 2D-CT scan to detect ossicular lesions in patients surgically managed. The CT scans were performed using a 40-section spiral CT scanner in 49 patients with post-traumatic CHL (n=29) and without CHL (n=20). Three radiologists performed independent blind evaluations of 2D-CT and 3D reconstructions to detect ossicular chain injury. We used the t-test to explore differences regarding the number of subjects with ossicular injury in the two groups. We also estimated the diagnostic accuracy and the inter-rater agreement of the 3D-CT reconstructions associated to 2D-CT scan. We identified ossicular abnormality in 14 patients out of 29 and in one patient out of 20 in the CHL and non-CHL groups respectively. There was a significant difference regarding the number of subjects with ossicular lesions between the two groups (P≤0.01). The diagnostic sensitivity of 3D-CT reconstructions associated with 2D-CT ranged from 66% to 100% and the inter-reader agreement ranged from 0.85 to 1, depending of the type of lesion. The relationship between ossicular lesion and the presence of CHL tightly correlated. 3D-CT reconstructions of the temporal bone are useful to assess patients in a post-traumatic context. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method

    NASA Astrophysics Data System (ADS)

    Kakakhel, M. B.; Kairn, T.; Kenny, J.; Trapp, J. V.

    2013-06-01

    In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the 'zero-scan' method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scanner's x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels.

  7. Peripheral pulmonary arteries: identification at multi-slice spiral CT with 3D reconstruction.

    PubMed

    Coche, Emmanuel; Pawlak, Sebastien; Dechambre, Stéphane; Maldague, Baudouin

    2003-04-01

    Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries.

  8. A prototype optical-CT system for PRESAGE 3D dosimeter readout

    NASA Astrophysics Data System (ADS)

    Miles, Devin; Yoon, Paul; Kodra, Jacob; Adamovics, John; Oldham, Mark

    2017-05-01

    This work introduces the Duke Integrated-lens Optical Scanner (DIOS), a prototype optical-CT system designed for convenient and low-cost readout of PRESAGE 3D dosimeters. A key novelty of the DIOS is the incorporation of a multi-purpose light-collimating tank (the LC-tank). The LC-tank collimates light from a point source, maintains parallel ray geometry through a dosimeter mounted inside the tank, and refocuses emergent light onto a CCD detector. A second purpose is to dramatically reduce the amount of refractive matched fluid required in prior optical-CT scanners. This is achieved by substituting large quantities of refractive-matched fluid with solid RI-matched polyurethane. The advantages of DIOS include eliminating the need for expensive telecentric lenses, and eliminating the impracticality of large volumes of RI matched fluid. The DIOS is potentially more susceptible to stray-light artifacts. Preliminary phantom testing shows promising agreement between PRESAGE/DIOS readout and prior commissioned optical-CT scanners, as well as with Eclipse dose calculations.

  9. Swarm Intelligence Integrated Graph-Cut for Liver Segmentation from 3D-CT Volumes

    PubMed Central

    Eapen, Maya; Korah, Reeba; Geetha, G.

    2015-01-01

    The segmentation of organs in CT volumes is a prerequisite for diagnosis and treatment planning. In this paper, we focus on liver segmentation from contrast-enhanced abdominal CT volumes, a challenging task due to intensity overlapping, blurred edges, large variability in liver shape, and complex background with cluttered features. The algorithm integrates multidiscriminative cues (i.e., prior domain information, intensity model, and regional characteristics of liver in a graph-cut image segmentation framework). The paper proposes a swarm intelligence inspired edge-adaptive weight function for regulating the energy minimization of the traditional graph-cut model. The model is validated both qualitatively (by clinicians and radiologists) and quantitatively on publically available computed tomography (CT) datasets (MICCAI 2007 liver segmentation challenge, 3D-IRCAD). Quantitative evaluation of segmentation results is performed using liver volume calculations and a mean score of 80.8% and 82.5% on MICCAI and IRCAD dataset, respectively, is obtained. The experimental result illustrates the efficiency and effectiveness of the proposed method. PMID:26689833

  10. Extraction and classification of 3D objects from volumetric CT data

    NASA Astrophysics Data System (ADS)

    Song, Samuel M.; Kwon, Junghyun; Ely, Austin; Enyeart, John; Johnson, Chad; Lee, Jongkyu; Kim, Namho; Boyd, Douglas P.

    2016-05-01

    We propose an Automatic Threat Detection (ATD) algorithm for Explosive Detection System (EDS) using our multistage Segmentation Carving (SC) followed by Support Vector Machine (SVM) classifier. The multi-stage Segmentation and Carving (SC) step extracts all suspect 3-D objects. The feature vector is then constructed for all extracted objects and the feature vector is classified by the Support Vector Machine (SVM) previously learned using a set of ground truth threat and benign objects. The learned SVM classifier has shown to be effective in classification of different types of threat materials. The proposed ATD algorithm robustly deals with CT data that are prone to artifacts due to scatter, beam hardening as well as other systematic idiosyncrasies of the CT data. Furthermore, the proposed ATD algorithm is amenable for including newly emerging threat materials as well as for accommodating data from newly developing sensor technologies. Efficacy of the proposed ATD algorithm with the SVM classifier is demonstrated by the Receiver Operating Characteristics (ROC) curve that relates Probability of Detection (PD) as a function of Probability of False Alarm (PFA). The tests performed using CT data of passenger bags shows excellent performance characteristics.

  11. Accuracy of 3D volumetric image registration based on CT, MR and PET/CT phantom experiments.

    PubMed

    Li, Guang; Xie, Huchen; Ning, Holly; Citrin, Deborah; Capala, Jacek; Maass-Moreno, Roberto; Guion, Peter; Arora, Barbara; Coleman, Norman; Camphausen, Kevin; Miller, Robert W

    2008-07-09

    Registration is critical for image-based treatment planning and image-guided treatment delivery. Although automatic registration is available, manual, visual-based image fusion using three orthogonal planar views (3P) is always employed clinically to verify and adjust an automatic registration result. However, the 3P fusion can be time consuming, observer dependent, as well as prone to errors, owing to the incomplete 3-dimensional (3D) volumetric image representations. It is also limited to single-pixel precision (the screen resolution). The 3D volumetric image registration (3DVIR) technique was developed to overcome these shortcomings. This technique introduces a 4th dimension in the registration criteria beyond the image volume, offering both visual and quantitative correlation of corresponding anatomic landmarks within the two registration images, facilitating a volumetric image alignment, and minimizing potential registration errors. The 3DVIR combines image classification in real-time to select and visualize a reliable anatomic landmark, rather than using all voxels for alignment. To determine the detection limit of the visual and quantitative 3DVIR criteria, slightly misaligned images were simulated and presented to eight clinical personnel for interpretation. Both of the criteria produce a detection limit of 0.1 mm and 0.1 degree. To determine the accuracy of the 3DVIR method, three imaging modalities (CT, MR and PET/CT) were used to acquire multiple phantom images with known spatial shifts. Lateral shifts were applied to these phantoms with displacement intervals of 5.0+/-0.1 mm. The accuracy of the 3DVIR technique was determined by comparing the image shifts determined through registration to the physical shifts made experimentally. The registration accuracy, together with precision, was found to be: 0.02+/-0.09 mm for CT/CT images, 0.03+/-0.07 mm for MR/MR images, and 0.03+/-0.35 mm for PET/CT images. This accuracy is consistent with the detection limit

  12. "High-precision, reconstructed 3D model" of skull scanned by conebeam CT: Reproducibility verified using CAD/CAM data.

    PubMed

    Katsumura, Seiko; Sato, Keita; Ikawa, Tomoko; Yamamura, Keiko; Ando, Eriko; Shigeta, Yuko; Ogawa, Takumi

    2016-01-01

    Computed tomography (CT) scanning has recently been introduced into forensic medicine and dentistry. However, the presence of metal restorations in the dentition can adversely affect the quality of three-dimensional reconstruction from CT scans. In this study, we aimed to evaluate the reproducibility of a "high-precision, reconstructed 3D model" obtained from a conebeam CT scan of dentition, a method that might be particularly helpful in forensic medicine. We took conebeam CT and helical CT images of three dry skulls marked with 47 measuring points; reconstructed three-dimensional images; and measured the distances between the points in the 3D images with a computer-aided design/computer-aided manufacturing (CAD/CAM) marker. We found that in comparison with the helical CT, conebeam CT is capable of reproducing measurements closer to those obtained from the actual samples. In conclusion, our study indicated that the image-reproduction from a conebeam CT scan was more accurate than that from a helical CT scan. Furthermore, the "high-precision reconstructed 3D model" facilitates reliable visualization of full-sized oral and maxillofacial regions in both helical and conebeam CT scans.

  13. 3D documentation and visualization of external injury findings by integration of simple photography in CT/MRI data sets (IprojeCT).

    PubMed

    Campana, Lorenzo; Breitbeck, Robert; Bauer-Kreuz, Regula; Buck, Ursula

    2016-05-01

    This study evaluated the feasibility of documenting patterned injury using three dimensions and true colour photography without complex 3D surface documentation methods. This method is based on a generated 3D surface model using radiologic slice images (CT) while the colour information is derived from photographs taken with commercially available cameras. The external patterned injuries were documented in 16 cases using digital photography as well as highly precise photogrammetry-supported 3D structured light scanning. The internal findings of these deceased were recorded using CT and MRI. For registration of the internal with the external data, two different types of radiographic markers were used and compared. The 3D surface model generated from CT slice images was linked with the photographs, and thereby digital true-colour 3D models of the patterned injuries could be created (Image projection onto CT/IprojeCT). In addition, these external models were merged with the models of the somatic interior. We demonstrated that 3D documentation and visualization of external injury findings by integration of digital photography in CT/MRI data sets is suitable for the 3D documentation of individual patterned injuries to a body. Nevertheless, this documentation method is not a substitution for photogrammetry and surface scanning, especially when the entire bodily surface is to be recorded in three dimensions including all external findings, and when precise data is required for comparing highly detailed injury features with the injury-inflicting tool.

  14. Novel and powerful 3D adaptive crisp active contour method applied in the segmentation of CT lung images.

    PubMed

    Rebouças Filho, Pedro Pedrosa; Cortez, Paulo César; da Silva Barros, Antônio C; C Albuquerque, Victor Hugo; R S Tavares, João Manuel

    2017-01-01

    The World Health Organization estimates that 300 million people have asthma, 210 million people have Chronic Obstructive Pulmonary Disease (COPD), and, according to WHO, COPD will become the third major cause of death worldwide in 2030. Computational Vision systems are commonly used in pulmonology to address the task of image segmentation, which is essential for accurate medical diagnoses. Segmentation defines the regions of the lungs in CT images of the thorax that must be further analyzed by the system or by a specialist physician. This work proposes a novel and powerful technique named 3D Adaptive Crisp Active Contour Method (3D ACACM) for the segmentation of CT lung images. The method starts with a sphere within the lung to be segmented that is deformed by forces acting on it towards the lung borders. This process is performed iteratively in order to minimize an energy function associated with the 3D deformable model used. In the experimental assessment, the 3D ACACM is compared against three approaches commonly used in this field: the automatic 3D Region Growing, the level-set algorithm based on coherent propagation and the semi-automatic segmentation by an expert using the 3D OsiriX toolbox. When applied to 40 CT scans of the chest the 3D ACACM had an average F-measure of 99.22%, revealing its superiority and competency to segment lungs in CT images.

  15. Calcification detection of abdominal aorta in CT images and 3D visualization in VR devices.

    PubMed

    Garcia-Berna, Jose A; Sanchez-Gomez, Juan M; Hermanns, Judith; Garcia-Mateos, Gines; Fernandez-Aleman, Jose L

    2016-08-01

    Automatic calcification detection in abdominal aorta consists of a set of computer vision techniques to quantify the amount of calcium that is found around this artery. Knowing that information, it is possible to perform statistical studies that relate vascular diseases with the presence of calcium in these structures. To facilitate the detection in CT images, a contrast is usually injected into the circulatory system of the patients to distinguish the aorta from other body tissues and organs. This contrast increases the absorption of X-rays by human blood, making it easier the measurement of calcifications. Based on this idea, a new system capable of detecting and tracking the aorta artery has been developed with an estimation of the calcium found surrounding the aorta. Besides, the system is complemented with a 3D visualization mode of the image set which is designed for the new generation of immersive VR devices.

  16. Visualising, segmenting and analysing heterogenous glacigenic sediments using 3D x-ray CT.

    NASA Astrophysics Data System (ADS)

    Carr, Simon; Diggens, Lucy; Groves, John; O'Sullivan, Catherine; Marsland, Rhona

    2015-04-01

    Whilst there has been significant application of 3D x-ray CT to geological contexts, much of this work has focused on examining properties such as porosity, which are important in reservoir assessment and hydrological evaluations. There has been considerably less attention given to the analysis of the properties of sediments themselves. One particular challenge in CT analysis is to effectively observe and discriminate the relationships between the skeleton and matrix of a sediment. This is particularly challenging in glacial sediments, which comprise an admixture of particles of a wide range of size, morphology and composition within a variably-consolidated sediment body. A key sedimentological component of glacial sediments is their fabric properties. Till fabric data has long been applied to the analysis of the coupling between glaciers and their deformable substrates. This work has typically focused on identifying former ice-flow directions, processes of till deformation and emplacement, and such data is often used to reconcile the sedimentary evidence of former glaciation with the predicted glacier and ice-sheet dynamics derived from numerical models. The collection and interpretation of till fabric data has received significant criticism in recent years, with issues such as low sample populations (typically ~50 grains per sample), small-scale spatial variation in till fabric and operator bias during data collection, all of which compromise the reliability of macro-scale till fabric analysis. Recent studies of micro-scale till fabrics have substantially added to our understanding, and suggest there is systematic variation in particle fabric as a function of particle size. However, these findings are compromised by the 2D nature of the samples (derived from thin sections) capturing only apparent orientations of particles, and are again limited to relatively small datasets. As such, there are fundamental limitations in the quality and application of till fabric

  17. Reduced-dose chest CT with 3D automatic exposure control vs. standard chest CT: quantitative assessment of emphysematous changes in smokers' lung parenchyma.

    PubMed

    Koyama, Hisanobu; Ohno, Yoshiharu; Yamazaki, Youichi; Matsumoto, Keiko; Onishi, Yumiko; Takenaka, Daisuke; Yoshikawa, Takeshi; Nishio, Mizuho; Matsumoto, Sumiaki; Murase, Kenya; Nishimura, Yoshihiro; Sugimura, Kazuro

    2012-06-01

    To determine the capability of reduced-dose chest CT with three-dimensional (3D) automatic exposure control (AEC) on quantitative assessment of emphysematous change in smoker' lung parenchyma, compared to standard chest CT. Twenty consecutive smoker patients (mean age 62.8 years) underwent CT examinations using a standard protocol (150 mAs) and a protocol with 3D-AEC. In this study, the targeted standard deviations number was set to 160. For quantitative assessment of emphysematous change in lung parenchyma in each subject using the standard protocol, a percentage of voxels less than -950 HU in the lung (%LAA(-950)) was calculated. The 3D-AEC protocol's %LAA was computed from of voxel percentages under selected threshold CT value. The differences of radiation doses between these two protocols were evaluated, and %LAAs(-950) was compared with the 3D-AEC protocol %LAAs. Mean dose length products were 780.2 ± 145.5 mGy cm (standard protocol), and 192.0 ± 95.9 (3D-AEC protocol). There was significant difference between them (paired Student's t test, p<0.00001). Meanwhile, only setting -960 HU yielded no significant difference (paired Student's t test, p=0.32) between %LAAs(-950) and 3D-AEC protocol %LAAs. In adopting the feasible threshold CT values of the 3D-AEC protocol, the 3D-AEC protocol %LAAs were significantly correlated with %LAAs(-950) (r = 0.98, p<0.001) and limits of agreement from Bland-Altman analysis was 0.52 ± 4.3%. Changing threshold CT values demonstrated that reduced-dose chest CT with 3D-AEC can substitute for the standard protocol in assessments of emphysematous change in smoker' lung parenchyma. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  18. 3D segmentation and image annotation for quantitative diagnosis in lung CT images with pulmonary lesions

    NASA Astrophysics Data System (ADS)

    Li, Suo; Zhu, Yanjie; Sun, Jianyong; Zhang, Jianguo

    2013-03-01

    Pulmonary nodules and ground glass opacities are highly significant findings in high-resolution computed tomography (HRCT) of patients with pulmonary lesion. The appearances of pulmonary nodules and ground glass opacities show a relationship with different lung diseases. According to corresponding characteristic of lesion, pertinent segment methods and quantitative analysis are helpful for control and treat diseases at an earlier and potentially more curable stage. Currently, most of the studies have focused on two-dimensional quantitative analysis of these kinds of deceases. Compared to two-dimensional images, three-dimensional quantitative analysis can take full advantage of isotropic image data acquired by using thin slicing HRCT in space and has better quantitative precision for clinical diagnosis. This presentation designs a computer-aided diagnosis component to segment 3D disease areas of nodules and ground glass opacities in lung CT images, and use AIML (Annotation and image makeup language) to annotate the segmented 3D pulmonary lesions with information of quantitative measurement which may provide more features and information to the radiologists in clinical diagnosis.

  19. 3D Alternating Direction TV-Based Cone-Beam CT Reconstruction with Efficient GPU Implementation

    PubMed Central

    Cai, Ailong; Zhang, Hanming; Li, Lei; Xi, Xiaoqi; Guan, Min; Li, Jianxin

    2014-01-01

    Iterative image reconstruction (IIR) with sparsity-exploiting methods, such as total variation (TV) minimization, claims potentially large reductions in sampling requirements. However, the computation complexity becomes a heavy burden, especially in 3D reconstruction situations. In order to improve the performance for iterative reconstruction, an efficient IIR algorithm for cone-beam computed tomography (CBCT) with GPU implementation has been proposed in this paper. In the first place, an algorithm based on alternating direction total variation using local linearization and proximity technique is proposed for CBCT reconstruction. The applied proximal technique avoids the horrible pseudoinverse computation of big matrix which makes the proposed algorithm applicable and efficient for CBCT imaging. The iteration for this algorithm is simple but convergent. The simulation and real CT data reconstruction results indicate that the proposed algorithm is both fast and accurate. The GPU implementation shows an excellent acceleration ratio of more than 100 compared with CPU computation without losing numerical accuracy. The runtime for the new 3D algorithm is about 6.8 seconds per loop with the image size of 256 × 256 × 256 and 36 projections of the size of 512 × 512. PMID:25045400

  20. Fast and Automatic Heart Isolation in 3D CT Volumes: Optimal Shape Initialization

    NASA Astrophysics Data System (ADS)

    Zheng, Yefeng; Vega-Higuera, Fernando; Zhou, Shaohua Kevin; Comaniciu, Dorin

    Heart isolation (separating the heart from the proximity tissues, e.g., lung, liver, and rib cage) is a prerequisite to clearly visualize the coronary arteries in 3D. Such a 3D visualization provides an intuitive view to physicians to diagnose suspicious coronary segments. Heart isolation is also necessary in radiotherapy planning to mask out the heart for the treatment of lung or liver tumors. In this paper, we propose an efficient and robust method for heart isolation in computed tomography (CT) volumes. Marginal space learning (MSL) is used to efficiently estimate the position, orientation, and scale of the heart. An optimal mean shape (which optimally represents the whole shape population) is then aligned with detected pose, followed by boundary refinement using a learning-based boundary detector. Post-processing is further exploited to exclude the rib cage from the heart mask. A large-scale experiment on 589 volumes (including both contrasted and non-contrasted scans) from 288 patients demonstrates the robustness of the approach. It achieves a mean point-to-mesh error of 1.91 mm. Running at a speed of 1.5 s/volume, it is at least 10 times faster than the previous methods.

  1. Radiation dose reduction for coronary artery calcium scoring at 320-detector CT with adaptive iterative dose reduction 3D.

    PubMed

    Tatsugami, Fuminari; Higaki, Toru; Fukumoto, Wataru; Kaichi, Yoko; Fujioka, Chikako; Kiguchi, Masao; Yamamoto, Hideya; Kihara, Yasuki; Awai, Kazuo

    2015-06-01

    To assess the possibility of reducing the radiation dose for coronary artery calcium (CAC) scoring by using adaptive iterative dose reduction 3D (AIDR 3D) on a 320-detector CT scanner. Fifty-four patients underwent routine- and low-dose CT for CAC scoring. Low-dose CT was performed at one-third of the tube current used for routine-dose CT. Routine-dose CT was reconstructed with filtered back projection (FBP) and low-dose CT was reconstructed with AIDR 3D. We compared the calculated Agatston-, volume-, and mass scores of these images. The overall percentage difference in the Agatston-, volume-, and mass scores between routine- and low-dose CT studies was 15.9, 11.6, and 12.6%, respectively. There were no significant differences in the routine- and low-dose CT studies irrespective of the scoring algorithms applied. The CAC measurements of both imaging modalities were highly correlated with respect to the Agatston- (r = 0.996), volume- (r = 0.996), and mass score (r = 0.997; p < 0.001, all); the Bland-Altman limits of agreement scores were -37.4 to 51.4, -31.2 to 36.4 and -30.3 to 40.9%, respectively, suggesting that AIDR 3D was a good alternative for FBP. The mean effective radiation dose for routine- and low-dose CT was 2.2 and 0.7 mSv, respectively. The use of AIDR 3D made it possible to reduce the radiation dose by 67% for CAC scoring without impairing the quantification of coronary calcification.

  2. Objective and subjective comparison of standard 2-D and fully 3-D reconstructed data on a PET/CT system.

    PubMed

    Strobel, Klaus; Rüdy, Matthias; Treyer, Valerie; Veit-Haibach, Patrick; Burger, Cyrill; Hany, Thomas F

    2007-07-01

    The relative advantage of fully 3-D versus 2-D mode for whole-body imaging is currently the focus of considerable expert debate. The nature of 3-D PET acquisition for FDG PET/CT theoretically allows a shorter scan time and improved efficiency of FDG use than in the standard 2-D acquisition. We therefore objectively and subjectively compared standard 2-D and fully 3-D reconstructed data for FDG PET/CT on a research PET/CT system. In a total of 36 patients (mean 58.9 years, range 17.3-78.9 years; 21 male, 15 female) referred for known or suspected malignancy, FDG PET/CT was performed using a research PET/CT system with advanced detector technology with improved sensitivity and spatial resolution. After 45 min uptake, a low-dose CT (40 mAs) from head to thigh was performed followed by 2-D PET (emission 3 min per field) and 3-D PET (emission 1.5 min per field) with both seven slices overlap to cover the identical anatomical region. Acquisition time was therefore 50% less (seven fields; 21 min vs. 10.5 min). PET data was acquired in a randomized fashion, so in 50% of the cases 2-D data was acquired first. CT data was used for attenuation correction. 2-D (OSEM) and 3-D PET images were iteratively reconstructed. Subjective analysis of 2-D and 3-D images was performed by two readers in a blinded, randomized fashion evaluating the following criteria: sharpness of organs (liver, chest wall/lung), overall image quality and detectability and dignity of each identified lesion. Objective analysis of PET data was investigated measuring maximum standard uptake value with lean body mass (SUV(max,LBM)) of identified lesions. On average, per patient, the SUV(max) was 7.86 (SD 7.79) for 2-D and 6.96 (SD 5.19) for 3-D. On a lesion basis, the average SUV(max) was 7.65 (SD 7.79) for 2-D and 6.75 (SD 5.89) for 3-D. The absolute difference on a paired t-test of SUV 3-D-2-D based on each measured lesion was significant with an average of -0.956 (P=0.002) and an average of -0.884 on a

  3. Inter-algorithm lesion volumetry comparison of real and 3D simulated lung lesions in CT

    NASA Astrophysics Data System (ADS)

    Robins, Marthony; Solomon, Justin; Hoye, Jocelyn; Smith, Taylor; Ebner, Lukas; Samei, Ehsan

    2017-03-01

    The purpose of this study was to establish volumetric exchangeability between real and computational lung lesions in CT. We compared the overall relative volume estimation performance of segmentation tools when used to measure real lesions in actual patient CT images and computational lesions virtually inserted into the same patient images (i.e., hybrid datasets). Pathologically confirmed malignancies from 30 thoracic patient cases from Reference Image Database to Evaluate Therapy Response (RIDER) were modeled and used as the basis for the comparison. Lesions included isolated nodules as well as those attached to the pleura or other lung structures. Patient images were acquired using a 16 detector row or 64 detector row CT scanner (Lightspeed 16 or VCT; GE Healthcare). Scans were acquired using standard chest protocols during a single breath-hold. Virtual 3D lesion models based on real lesions were developed in Duke Lesion Tool (Duke University), and inserted using a validated image-domain insertion program. Nodule volumes were estimated using multiple commercial segmentation tools (iNtuition, TeraRecon, Inc., Syngo.via, Siemens Healthcare, and IntelliSpace, Philips Healthcare). Consensus based volume comparison showed consistent trends in volume measurement between real and virtual lesions across all software. The average percent bias (+/- standard error) shows -9.2+/-3.2% for real lesions versus -6.7+/-1.2% for virtual lesions with tool A, 3.9+/-2.5% and 5.0+/-0.9% for tool B, and 5.3+/-2.3% and 1.8+/-0.8% for tool C, respectively. Virtual lesion volumes were statistically similar to those of real lesions (< 4% difference) with p >.05 in most cases. Results suggest that hybrid datasets had similar inter-algorithm variability compared to real datasets.

  4. Reliability analysis of Cobb angle measurements of congenital scoliosis using X-ray and 3D-CT images.

    PubMed

    Tauchi, Ryoji; Tsuji, Taichi; Cahill, Patrick J; Flynn, John M; Flynn, John M; Glotzbecker, Michael; El-Hawary, Ron; Heflin, John A; Imagama, Shiro; Joshi, Ajeya P; Nohara, Ayato; Ramirez, Norman; Roye, David P; Saito, Toshiki; Sawyer, Jeffrey R; Smith, John T; Kawakami, Noriaki

    2016-01-01

    Therapeutic decisions for congenital scoliosis rely on Cobb angle measurements on consecutive radiographs. There have been no studies documenting the variability of measuring the Cobb angle using 3D-CT images in children with congenital scoliosis. The purpose of this study was to compare the reliability and measurement errors using X-ray images and those utilizing 3D-CT images. The X-ray and 3D-CT images of 20 patients diagnosed with congenital scoliosis were used to assess the reliability of the digital 3D-CT images for the measurement of the Cobb angle. Thirteen observers performed the measurements, and each image was analyzed by each observer twice with a minimum interval of 1 week between measurements. The analysis of intraobserver variation was expressed as the mean absolute difference (MAD) and standard deviation (SD) between measurements and the intraclass correlation coefficient (IaCC) of the measurements. In addition, the interobserver variation was expressed as the MAD and interclass correlation coefficient (IeCC). The average MAD and SD was 4.5° and 3.2° by the X-ray method and 3.7° and 2.6° by the 3D-CT method. The intraobserver and interobserver intraclass ICCs were excellent in both methods (X-ray: IaCC 0.835-0.994 IeCC 0.847, 3D-CT: IaCC 0.819-0.996 IeCC 0.893). There was no significant MAD difference between X-ray and 3D-CT images in measuring each type of congenital scoliosis by each observer. Results of Cobb angle measurements in patients with congenital scoliosis using X-ray images in the frontal plane could be reproduced with almost the same measurement variance (3°-4° measurement error) using 3D-CT images. This suggests that X-ray images are clinically useful for assessing any type of congenital scoliosis about measuring the Cobb angle alone. However, since 3D-CT can provide more detailed images of the anterior and posterior components of malformed vertebrae, the volume of information that can be obtained by evaluating them has

  5. Adaptive Iterative Dose Reduction Using Three Dimensional Processing (AIDR3D) Improves Chest CT Image Quality and Reduces Radiation Exposure

    PubMed Central

    Yamashiro, Tsuneo; Miyara, Tetsuhiro; Honda, Osamu; Kamiya, Hisashi; Murata, Kiyoshi; Ohno, Yoshiharu; Tomiyama, Noriyuki; Moriya, Hiroshi; Koyama, Mitsuhiro; Noma, Satoshi; Kamiya, Ayano; Tanaka, Yuko; Murayama, Sadayuki

    2014-01-01

    Objective To assess the advantages of Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D) for image quality improvement and dose reduction for chest computed tomography (CT). Methods Institutional Review Boards approved this study and informed consent was obtained. Eighty-eight subjects underwent chest CT at five institutions using identical scanners and protocols. During a single visit, each subject was scanned using different tube currents: 240, 120, and 60 mA. Scan data were converted to images using AIDR3D and a conventional reconstruction mode (without AIDR3D). Using a 5-point scale from 1 (non-diagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for three lung zones, four patterns of lung disease (nodule/mass, emphysema, bronchiolitis, and diffuse lung disease), and three mediastinal measurements (small structure visibility, streak artifacts, and shoulder artifacts). Differences in these scores were assessed by Scheffe's test. Results At each tube current, scans using AIDR3D had higher scores than those without AIDR3D, which were significant for lung zones (p<0.0001) and all mediastinal measurements (p<0.01). For lung diseases, significant improvements with AIDR3D were frequently observed at 120 and 60 mA. Scans with AIDR3D at 120 mA had significantly higher scores than those without AIDR3D at 240 mA for lung zones and mediastinal streak artifacts (p<0.0001), and slightly higher or equal scores for all other measurements. Scans with AIDR3D at 60 mA were also judged superior or equivalent to those without AIDR3D at 120 mA. Conclusion For chest CT, AIDR3D provides better image quality and can reduce radiation exposure by 50%. PMID:25153797

  6. Computerized identification of airway wall in CT examinations using a 3D active surface evolution approach.

    PubMed

    Gu, Suicheng; Fuhrman, Carl; Meng, Xin; Siegfried, Jill M; Gur, David; Leader, Joseph K; Sciurba, Frank C; Pu, Jiantao

    2013-04-01

    Airway diseases (e.g., asthma, emphysema, and chronic bronchitis) are extremely common worldwide. Any morphological variations (abnormalities) of airways may physically change airflow and ultimately affect the ability of the lungs in gas exchange. In this study, we describe a novel algorithm aimed to automatically identify airway walls depicted on CT images. The underlying idea is to place a three-dimensional (3D) surface model within airway regions and thereafter allow this model to evolve (deform) under predefined external and internal forces automatically to the location where these forces reach a state of balance. By taking advantage of the geometric and the density characteristics of airway walls, the evolution procedure is performed in a distance gradient field and ultimately stops at regions with the highest contrast. The performance of this scheme was quantitatively evaluated from several perspectives. First, we assessed the accuracy of the developed scheme using a dedicated lung phantom in airway wall estimation and compared it with the traditional full-width at half maximum (FWHM) method. The phantom study shows that the developed scheme has an error ranging from 0.04 mm to 0.36 mm, which is much smaller than the FWHM method with an error ranging from 0.16 mm to 0.84 mm. Second, we compared the results obtained by the developed scheme with those manually delineated by an experienced (>30 years) radiologist on clinical chest CT examinations, showing a mean difference of 0.084 mm. In particular, the sensitivity of the scheme to different reconstruction kernels was evaluated on real chest CT examinations. For the 'lung', 'bone' and 'standard' kernels, the average airway wall thicknesses computed by the developed scheme were 1.302 mm, 1.333 mm and 1.339 mm, respectively. Our preliminary experiments showed that the scheme had a reasonable accuracy in airway wall estimation. For a clinical chest CT examination, it took around 4 min for this scheme to identify

  7. An adaptive approach to centerline extraction for CT colonography using MAP-EM segmentation and distance field

    NASA Astrophysics Data System (ADS)

    Peng, Hao; Li, Lihong C.; Wang, Huafeng; Han, Hao; Pickhardt, Perry J.; Liang, Zhengrong

    2014-03-01

    In this paper, we present an adaptive approach for fully automatic centerline extraction and small intestine removal based on partial volume (PV) image segmentation and distance field modeling. Computed tomographic colonography (CTC) volume image is first segmented for the colon wall mucosa layer, which represents the PV effect around the colon wall. Then centerline extraction is performed in the presence of colon collapse and small intestine touch by the use of distance field within the segmented PV mucosa layer, where centerline breakings due to collapse are recovered and centerline branches due to small intestine tough are removed. Experimental results from 24 patient CTC scans with small intestine touch rendered 100% removal of the touch, while only 16 out of the 24 could be done by the well-known isolated component method. Our voxel-by-voxel marking strategy in the automated procedure preserves the topology and validity of the colon structure. The marked inner and outer boundaries on cleansed colon are very close to those labeled by the experts. Experimental results demonstrated the robustness and efficiency of the presented adaptive approach for CTC utility.

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

    PubMed

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

    2013-11-01

    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. 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. 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. 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. Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  9. Automatic 3D-to-2D registration for CT and dual-energy digital radiography for calcification detection

    SciTech Connect

    Chen Xiang; Gilkeson, Robert C.; Fei, Baowei

    2007-12-15

    We are investigating three-dimensional (3D) to two-dimensional (2D) registration methods for computed tomography (CT) and dual-energy digital radiography (DEDR). CT is an established tool for the detection of cardiac calcification. DEDR could be a cost-effective alternative screening tool. In order to utilize CT as the 'gold standard' to evaluate the capability of DEDR images for the detection and localization of calcium, we developed an automatic, intensity-based 3D-to-2D registration method for 3D CT volumes and 2D DEDR images. To generate digitally reconstructed radiography (DRR) from the CT volumes, we developed several projection algorithms using the fast shear-warp method. In particular, we created a Gaussian-weighted projection for this application. We used normalized mutual information (NMI) as the similarity measurement. Simulated projection images from CT values were fused with the corresponding DEDR images to evaluate the localization of cardiac calcification. The registration method was evaluated by digital phantoms, physical phantoms, and clinical data sets. The results from the digital phantoms show that the success rate is 100% with a translation difference of less than 0.8 mm and a rotation difference of less than 0.2 deg. . For physical phantom images, the registration accuracy is 0.43{+-}0.24 mm. Color overlay and 3D visualization of clinical images show that the two images registered well. The NMI values between the DRR and DEDR images improved from 0.21{+-}0.03 before registration to 0.25{+-}0.03 after registration. Registration errors measured from anatomic markers decreased from 27.6{+-}13.6 mm before registration to 2.5{+-}0.5 mm after registration. Our results show that the automatic 3D-to-2D registration is accurate and robust. This technique can provide a useful tool for correlating DEDR with CT images for screening coronary artery calcification.

  10. Pancreas segmentation from 3D abdominal CT images using patient-specific weighted subspatial probabilistic atlases

    NASA Astrophysics Data System (ADS)

    Karasawa, Kenichi; Oda, Masahiro; Hayashi, Yuichiro; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Rueckert, Daniel; Mori, Kensaku

    2015-03-01

    Abdominal organ segmentations from CT volumes are now widely used in the computer-aided diagnosis and surgery assistance systems. Among abdominal organs, the pancreas is especially difficult to segment because of its large individual differences of the shape and position. In this paper, we propose a new pancreas segmentation method from 3D abdominal CT volumes using patient-specific weighted-subspatial probabilistic atlases. First of all, we perform normalization of organ shapes in training volumes and an input volume. We extract the Volume Of Interest (VOI) of the pancreas from the training volumes and an input volume. We divide each training VOI and input VOI into some cubic regions. We use a nonrigid registration method to register these cubic regions of the training VOI to corresponding regions of the input VOI. Based on the registration results, we calculate similarities between each cubic region of the training VOI and corresponding region of the input VOI. We select cubic regions of training volumes having the top N similarities in each cubic region. We subspatially construct probabilistic atlases weighted by the similarities in each cubic region. After integrating these probabilistic atlases in cubic regions into one, we perform a rough-to-precise segmentation of the pancreas using the atlas. The results of the experiments showed that utilization of the training volumes having the top N similarities in each cubic region led good results of the pancreas segmentation. The Jaccard Index and the average surface distance of the result were 58.9% and 2.04mm on average, respectively.

  11. Registration uncertainties between 3D cone beam computed tomography and different reference CT datasets in lung stereotactic body radiation therapy.

    PubMed

    Oechsner, Markus; Chizzali, Barbara; Devecka, Michal; Combs, Stephanie Elisabeth; Wilkens, Jan Jakob; Duma, Marciana Nona

    2016-10-26

    The aim of this study was to analyze differences in couch shifts (setup errors) resulting from image registration of different CT datasets with free breathing cone beam CTs (FB-CBCT). As well automatic as manual image registrations were performed and registration results were correlated to tumor characteristics. FB-CBCT image registration was performed for 49 patients with lung lesions using slow planning CT (PCT), average intensity projection (AIP), maximum intensity projection (MIP) and mid-ventilation CTs (MidV) as reference images. Both, automatic and manual image registrations were applied. Shift differences were evaluated between the registered CT datasets for automatic and manual registration, respectively. Furthermore, differences between automatic and manual registration were analyzed for the same CT datasets. The registration results were statistically analyzed and correlated to tumor characteristics (3D tumor motion, tumor volume, superior-inferior (SI) distance, tumor environment). Median 3D shift differences over all patients were between 0.5 mm (AIPvsMIP) and 1.9 mm (MIPvsPCT and MidVvsPCT) for the automatic registration and between 1.8 mm (AIPvsPCT) and 2.8 mm (MIPvsPCT and MidVvsPCT) for the manual registration. For some patients, large shift differences (>5.0 mm) were found (maximum 10.5 mm, automatic registration). Comparing automatic vs manual registrations for the same reference CTs, ∆AIP achieved the smallest (1.1 mm) and ∆MIP the largest (1.9 mm) median 3D shift differences. The standard deviation (variability) for the 3D shift differences was also the smallest for ∆AIP (1.1 mm). Significant correlations (p < 0.01) between 3D shift difference and 3D tumor motion (AIPvsMIP, MIPvsMidV) and SI distance (AIPvsMIP) (automatic) and also for 3D tumor motion (∆PCT, ∆MidV; automatic vs manual) were found. Using different CT datasets for image registration with FB-CBCTs can result in different 3D couch shifts. Manual registrations

  12. Registration of 2D x-ray images to 3D MRI by generating pseudo-CT data

    NASA Astrophysics Data System (ADS)

    van der Bom, M. J.; Pluim, J. P. W.; Gounis, M. J.; van de Kraats, E. B.; Sprinkhuizen, S. M.; Timmer, J.; Homan, R.; Bartels, L. W.

    2011-02-01

    Spatial and soft tissue information provided by magnetic resonance imaging can be very valuable during image-guided procedures, where usually only real-time two-dimensional (2D) x-ray images are available. Registration of 2D x-ray images to three-dimensional (3D) magnetic resonance imaging (MRI) data, acquired prior to the procedure, can provide optimal information to guide the procedure. However, registering x-ray images to MRI data is not a trivial task because of their fundamental difference in tissue contrast. This paper presents a technique that generates pseudo-computed tomography (CT) data from multi-spectral MRI acquisitions which is sufficiently similar to real CT data to enable registration of x-ray to MRI with comparable accuracy as registration of x-ray to CT. The method is based on a k-nearest-neighbors (kNN)-regression strategy which labels voxels of MRI data with CT Hounsfield Units. The regression method uses multi-spectral MRI intensities and intensity gradients as features to discriminate between various tissue types. The efficacy of using pseudo-CT data for registration of x-ray to MRI was tested on ex vivo animal data. 2D-3D registration experiments using CT and pseudo-CT data of multiple subjects were performed with a commonly used 2D-3D registration algorithm. On average, the median target registration error for registration of two x-ray images to MRI data was approximately 1 mm larger than for x-ray to CT registration. The authors have shown that pseudo-CT data generated from multi-spectral MRI facilitate registration of MRI to x-ray images. From the experiments it could be concluded that the accuracy achieved was comparable to that of registering x-ray images to CT data.

  13. Automatic Segmentation of 3D Micro-CT Coronary Vascular Images

    SciTech Connect

    Lee,J.; Beighley, P.; Ritman, E.; Smith, N.

    2007-01-01

    Although there are many algorithms available in the literature aimed at segmentation and model reconstruction of 3D angiographic images, many are focused on characterizing only a part of the vascular network. This study is motivated by the recent emerging prospects of whole-organ simulations in coronary hemodynamics, autoregulation and tissue oxygen delivery for which anatomically accurate vascular meshes of extended scale are highly desirable. The key requirements of a reconstruction technique for this purpose are automation of processing and sub-voxel accuracy. We have designed a vascular reconstruction algorithm which satisfies these two criteria. It combines automatic seeding and tracking of vessels with radius detection based on active contours. The method was first examined through a series of tests on synthetic data, for accuracy in reproduced topology and morphology of the network and was shown to exhibit errors of less than 0.5 voxel for centerline and radius detections, and 3 for initial seed directions. The algorithm was then applied on real-world data of full rat coronary structure acquired using a micro-CT scanner at 20 {mu}m voxel size. For this, a further validation of radius quantification was carried out against a partially rescanned portion of the network at 8 {mu}m voxel size, which estimated less than 10% radius error in vessels larger than 2 voxels in radius.

  14. Automatic segmentation of 3D micro-CT coronary vascular images.

    PubMed

    Lee, Jack; Beighley, Patricia; Ritman, Erik; Smith, Nicolas

    2007-12-01

    Although there are many algorithms available in the literature aimed at segmentation and model reconstruction of 3D angiographic images, many are focused on characterizing only a part of the vascular network. This study is motivated by the recent emerging prospects of whole-organ simulations in coronary hemodynamics, autoregulation and tissue oxygen delivery for which anatomically accurate vascular meshes of extended scale are highly desirable. The key requirements of a reconstruction technique for this purpose are automation of processing and sub-voxel accuracy. We have designed a vascular reconstruction algorithm which satisfies these two criteria. It combines automatic seeding and tracking of vessels with radius detection based on active contours. The method was first examined through a series of tests on synthetic data, for accuracy in reproduced topology and morphology of the network and was shown to exhibit errors of less than 0.5 voxel for centerline and radius detections, and 3 degrees for initial seed directions. The algorithm was then applied on real-world data of full rat coronary structure acquired using a micro-CT scanner at 20 microm voxel size. For this, a further validation of radius quantification was carried out against a partially rescanned portion of the network at 8 microm voxel size, which estimated less than 10% radius error in vessels larger than 2 voxels in radius.

  15. Measurement of spiculation index in 3D for solitary pulmonary nodules in volumetric lung CT images

    NASA Astrophysics Data System (ADS)

    Dhara, Ashis Kumar; Mukhopadhyay, Sudipta; Alam, Naved; Khandelwal, Niranjan

    2013-02-01

    In this paper a differential geometry based method is proposed for calculating surface speculation of solitary pulmonary nodule (SPN) in 3D from lung CT images. Spiculation present in SPN is an important shape feature to assist radiologist for measurement of malignancy. Performance of Computer Aided Diagnostic (CAD) system depends on the accurate estimation of feature like spiculation. In the proposed method, the peak of the spicules is identified using the property of Gaussian and mean curvature calculated at each surface point on segmented SPN. Once the peak point for a particular SPN is identified, the nearest valley points for the corresponding peak point are determined. The area of cross-section of the best fitted plane passing through the valley points is the base of that spicule. The solid angle subtended by the base of spicule at peak point and the distance of peak point from nodule base are taken as the measures of spiculation. The speculation index (SI) for a particular SPN is the weighted combination of all the spicules present in that SPN. The proposed method is validated on 95 SPN from Imaging Database Resources Initiative (IDRI) public database. It has achieved 87.4% accuracy in calculating quantified spiculation index compared to the spiculation index provided by radiologists in IDRI database.

  16. A strain energy filter for 3D vessel enhancement with application to pulmonary CT images.

    PubMed

    Xiao, Changyan; Staring, Marius; Shamonin, Denis; Reiber, Johan H C; Stolk, Jan; Stoel, Berend C

    2011-02-01

    The traditional Hessian-related vessel filters often suffer from detecting complex structures like bifurcations due to an over-simplified cylindrical model. To solve this problem, we present a shape-tuned strain energy density function to measure vessel likelihood in 3D medical images. This method is initially inspired by established stress-strain principles in mechanics. By considering the Hessian matrix as a stress tensor, the three invariants from orthogonal tensor decomposition are used independently or combined to formulate distinctive functions for vascular shape discrimination, brightness contrast and structure strength measuring. Moreover, a mathematical description of Hessian eigenvalues for general vessel shapes is obtained, based on an intensity continuity assumption, and a relative Hessian strength term is presented to ensure the dominance of second-order derivatives as well as suppress undesired step-edges. Finally, we adopt the multi-scale scheme to find an optimal solution through scale space. The proposed method is validated in experiments with a digital phantom and non-contrast-enhanced pulmonary CT data. It is shown that our model performed more effectively in enhancing vessel bifurcations and preserving details, compared to three existing filters.

  17. Semi-automatic 3D lung nodule segmentation in CT using dynamic programming

    NASA Astrophysics Data System (ADS)

    Sargent, Dustin; Park, Sun Young

    2017-02-01

    We present a method for semi-automatic segmentation of lung nodules in chest CT that can be extended to general lesion segmentation in multiple modalities. Most semi-automatic algorithms for lesion segmentation or similar tasks use region-growing or edge-based contour finding methods such as level-set. However, lung nodules and other lesions are often connected to surrounding tissues, which makes these algorithms prone to growing the nodule boundary into the surrounding tissue. To solve this problem, we apply a 3D extension of the 2D edge linking method with dynamic programming to find a closed surface in a spherical representation of the nodule ROI. The algorithm requires a user to draw a maximal diameter across the nodule in the slice in which the nodule cross section is the largest. We report the lesion volume estimation accuracy of our algorithm on the FDA lung phantom dataset, and the RECIST diameter estimation accuracy on the lung nodule dataset from the SPIE 2016 lung nodule classification challenge. The phantom results in particular demonstrate that our algorithm has the potential to mitigate the disparity in measurements performed by different radiologists on the same lesions, which could improve the accuracy of disease progression tracking.

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

    SciTech Connect

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

    2011-12-15

    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%.

  19. Clinical Application of Solid Model Based on Trabecular Tibia Bone CT Images Created by 3D Printer.

    PubMed

    Cho, Jaemo; Park, Chan-Soo; Kim, Yeoun-Jae; Kim, Kwang Gi

    2015-07-01

    The aim of this work is to use a 3D solid model to predict the mechanical loads of human bone fracture risk associated with bone disease conditions according to biomechanical engineering parameters. We used special image processing tools for image segmentation and three-dimensional (3D) reconstruction to generate meshes, which are necessary for the production of a solid model with a 3D printer from computed tomography (CT) images of the human tibia's trabecular and cortical bones. We examined the defects of the mechanism for the tibia's trabecular bones. Image processing tools and segmentation techniques were used to analyze bone structures and produce a solid model with a 3D printer. These days, bio-imaging (CT and magnetic resonance imaging) devices are able to display and reconstruct 3D anatomical details, and diagnostics are becoming increasingly vital to the quality of patient treatment planning and clinical treatment. Furthermore, radiographic images are being used to study biomechanical systems with several aims, namely, to describe and simulate the mechanical behavior of certain anatomical systems, to analyze pathological bone conditions, to study tissues structure and properties, and to create a solid model using a 3D printer to support surgical planning and reduce experimental costs. These days, research using image processing tools and segmentation techniques to analyze bone structures to produce a solid model with a 3D printer is rapidly becoming very important.

  20. Clinical Application of Solid Model Based on Trabecular Tibia Bone CT Images Created by 3D Printer

    PubMed Central

    Cho, Jaemo; Park, Chan-Soo; Kim, Yeoun-Jae

    2015-01-01

    Objectives The aim of this work is to use a 3D solid model to predict the mechanical loads of human bone fracture risk associated with bone disease conditions according to biomechanical engineering parameters. Methods We used special image processing tools for image segmentation and three-dimensional (3D) reconstruction to generate meshes, which are necessary for the production of a solid model with a 3D printer from computed tomography (CT) images of the human tibia's trabecular and cortical bones. We examined the defects of the mechanism for the tibia's trabecular bones. Results Image processing tools and segmentation techniques were used to analyze bone structures and produce a solid model with a 3D printer. Conclusions These days, bio-imaging (CT and magnetic resonance imaging) devices are able to display and reconstruct 3D anatomical details, and diagnostics are becoming increasingly vital to the quality of patient treatment planning and clinical treatment. Furthermore, radiographic images are being used to study biomechanical systems with several aims, namely, to describe and simulate the mechanical behavior of certain anatomical systems, to analyze pathological bone conditions, to study tissues structure and properties, and to create a solid model using a 3D printer to support surgical planning and reduce experimental costs. These days, research using image processing tools and segmentation techniques to analyze bone structures to produce a solid model with a 3D printer is rapidly becoming very important. PMID:26279958

  1. Data-fusion of high resolution X-ray CT, SEM and EDS for 3D and pseudo-3D chemical and structural characterization of sandstone.

    PubMed

    De Boever, Wesley; Derluyn, Hannelore; Van Loo, Denis; Van Hoorebeke, Luc; Cnudde, Veerle

    2015-07-01

    When dealing with the characterization of the structure and composition of natural stones, problems of representativeness and choice of analysis technique almost always occur. Since feature-sizes are typically spread over the nanometer to centimeter range, there is never one single technique that allows a rapid and complete characterization. Over the last few decades, high resolution X-ray CT (μ-CT) has become an invaluable tool for the 3D characterization of many materials, including natural stones. This technique has many important advantages, but there are also some limitations, including a tradeoff between resolution and sample size and a lack of chemical information. For geologists, this chemical information is of importance for the determination of minerals inside samples. We suggest a workflow for the complete chemical and structural characterization of a representative volume of a heterogeneous geological material. This workflow consists of combining information derived from CT scans at different spatial resolutions with information from scanning electron microscopy and energy-dispersive X-ray spectroscopy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A prototype fan-beam optical CT scanner for 3D dosimetry

    SciTech Connect

    Campbell, Warren G.; Rudko, D. A.; Braam, Nicolas A.; Jirasek, Andrew; Wells, Derek M.

    2013-06-15

    flask registration technique was shown to achieve submillimetre and subdegree placement accuracy. Dosimetry protocol investigations emphasize the need to allow gel dosimeters to cool gradually and to be scanned while at room temperature. Preliminary tests show that considerable noise reduction can be achieved with sinogram filtering and by binning image pixels into more clinically relevant grid sizes. Conclusions: This paper describes a new optical CT scanner for 3D radiation dosimetry. Tests demonstrate that it is capable of imaging both absorption-based and scatter-based samples of high opacities. Imaging protocol and gel dosimeter manufacture techniques have been adapted to produce optimal reconstruction results. These optimal results will require suitable filtering and binning techniques for noise reduction purposes.

  3. A prototype fan-beam optical CT scanner for 3D dosimetry.

    PubMed

    Campbell, Warren G; Rudko, D A; Braam, Nicolas A; Wells, Derek M; Jirasek, Andrew

    2013-06-01

    submillimetre and subdegree placement accuracy. Dosimetry protocol investigations emphasize the need to allow gel dosimeters to cool gradually and to be scanned while at room temperature. Preliminary tests show that considerable noise reduction can be achieved with sinogram filtering and by binning image pixels into more clinically relevant grid sizes. This paper describes a new optical CT scanner for 3D radiation dosimetry. Tests demonstrate that it is capable of imaging both absorption-based and scatter-based samples of high opacities. Imaging protocol and gel dosimeter manufacture techniques have been adapted to produce optimal reconstruction results. These optimal results will require suitable filtering and binning techniques for noise reduction purposes.

  4. National CT Colonography Trial (ACRIN 6664): Comparison of Three Full-Laxative Bowel Preparations in More Than 2500 Average-Risk Patients

    PubMed Central

    Hara, Amy K.; Kuo, Mark D.; Blevins, Meridith; Chen, Mei-Hsiu; Yee, Judy; Dachman, Abraham; Menias, Christine O.; Siewert, Betina; Cheema, Jugesh I.; Obregon, Richard G.; Fidler, Jeff L.; Zimmerman, Peter; Horton, Karen M.; Coakley, Kevin; Iyer, Revathy B.; Halvorsen, Robert A.; Casola, Giovanna; Johnson, C. Daniel

    2011-01-01

    OBJECTIVE The purpose of our study was to compare the effect of three different full-laxative bowel preparations on patient compliance, residual stool and fluid, reader confidence, and polyp detection at CT colonography (CTC). SUBJECTS AND METHODS A total of 2531 patients underwent CTC followed by colonoscopy for the American College of Radiology Imaging Network (ACRIN) National CTC Trial. Of this total, 2525 patients used one of three bowel preparations with bisacodyl tablets and stool and fluid tagging: 4 L of polyethylene glycol (PEG); 90 mL of phosphosoda; or 300 mL of magnesium citrate. Patients reported percent compliance with the bowel preparation and radiologists graded each CTC examination for the amount of residual fluid and stool on a scale from 1 (none) to 4 (nondiagnostic). Reader confidence for true-positive findings was reported on a 5-point scale: 1 (low) to 5 (high). Sensitivity and specificity for detecting polyps ≥ 6 mm and ≥ 1 cm compared with colonoscopy were calculated for each preparation. RESULTS The most commonly prescribed preparation was phosphosoda (n = 1403) followed by PEG (n = 1020) and magnesium citrate (n = 102). Phosphosoda had the highest patient compliance (p = 0.01), least residual stool (p < 0.001), and highest reader confidence versus PEG for examinations with polyps (p = 0.06). Magnesium citrate had significantly more residual fluid compared with PEG and phosphosoda (p = 0.006). The sensitivity and specificity for detecting colon polyps ≥ 6 mm and ≥ 1 cm did not differ significantly between preparations. CONCLUSION Polyp detection was comparable for all three preparations, although phosphosoda had significantly higher patient compliance and the least residual stool. PMID:21512073

  5. Cascaded systems analysis of the 3D noise transfer characteristics of flat-panel cone-beam CT.

    PubMed

    Tward, Daniel J; Siewerdsen, Jeffrey H

    2008-12-01

    The physical factors that govern 2D and 3D imaging performance may be understood from quantitative analysis of the spatial-frequency-dependent signal and noise transfer characteristics [e.g., modulation transfer function (MTF), noise-power spectrum (NPS), detective quantum efficiency (DQE), and noise-equivalent quanta (NEQ)] along with a task-based assessment of performance (e.g., detectability index). This paper advances a theoretical framework based on cascaded systems analysis for calculation of such metrics in cone-beam CT (CBCT). The model considers the 2D projection NPS propagated through a series of reconstruction stages to yield the 3D NPS and allows quantitative investigation of tradeoffs in image quality associated with acquisition and reconstruction techniques. While the mathematical process of 3D image reconstruction is deterministic, it is shown that the process is irreversible, the associated reconstruction parameters significantly affect the 3D DQE and NEQ, and system optimization should consider the full 3D imaging chain. Factors considered in the cascade include: system geometry; number of projection views; logarithmic scaling; ramp, apodization, and interpolation filters; 3D back-projection; and 3D sampling (noise aliasing). The model is validated in comparison to experiment across a broad range of dose, reconstruction filters, and voxel sizes, and the effects of 3D noise correlation on detectability are explored. The work presents a model for the 3D NPS, DQE, and NEQ of CBCT that reduces to conventional descriptions of axial CT as a special case and provides a fairly general framework that can be applied to the design and optimization of CBCT systems for various applications.

  6. 3D texture analysis of solitary pulmonary nodules using co-occurrence matrix from volumetric lung CT images

    NASA Astrophysics Data System (ADS)

    Dhara, Ashis Kumar; Mukhopadhyay, Sudipta; Khandelwal, Niranjan

    2013-02-01

    In this paper we have investigated a new approach for texture features extraction using co-occurrence matrix from volumetric lung CT image. Traditionally texture analysis is performed in 2D and is suitable for images collected from 2D imaging modality. The use of 3D imaging modalities provide the scope of texture analysis from 3D object and 3D texture feature are more realistic to represent 3D object. In this work, Haralick's texture features are extended in 3D and computed from volumetric data considering 26 neighbors. The optimal texture features to characterize the internal structure of Solitary Pulmonary Nodules (SPN) are selected based on area under curve (AUC) values of ROC curve and p values from 2-tailed Student's t-test. The selected texture feature in 3D to represent SPN can be used in efficient Computer Aided Diagnostic (CAD) design plays an important role in fast and accurate lung cancer screening. The reduced number of input features to the CAD system will decrease the computational time and classification errors caused by irrelevant features. In the present work, SPN are classified from Ground Glass Nodule (GGN) using Artificial Neural Network (ANN) classifier considering top five 3D texture features and top five 2D texture features separately. The classification is performed on 92 SPN and 25 GGN from Imaging Database Resources Initiative (IDRI) public database and classification accuracy using 3D texture features and 2D texture features provide 97.17% and 89.1% respectively.

  7. Development of a 3D CT-scanner using a cone beam and video-fluoroscopic system.

    PubMed

    Endo, M; Yoshida, K; Kamagata, N; Satoh, K; Okazaki, T; Hattori, Y; Kobayashi, S; Jimbo, M; Kusakabe, M; Tateno, Y

    1998-01-01

    We describe the design and implementation of a system that acquires three-dimensional (3D) data of high-contrast objects such as bone, lung, and blood vessels (enhanced by contrast agent). This 3D computed tomography (CT) system is based on a cone beam and video-fluoroscopic system and yields data that is amenable to 3D image processing. An X-ray tube and a large area two-dimensional detector were mounted on a single frame and rotated around objects in 12 seconds. The large area detector consisted of a fluorescent plate and a charge coupled device (CCD) video camera. While the X-ray tube was rotated around the object, a pulsed X-ray was generated (30 pulses per second) and 360 projected images were collected in a 12-second scan. A 256 x 256 x 256 matrix image was reconstructed using a high-speed parallel processor. Reconstruction required approximately 6 minutes. Two volunteers underwent scans of the head or chest. High-contrast objects such as bronchial, vascular, and mediastinal structures in the thorax, or bones and air cavities in the head were delineated in a "real" 3D format. Our 3D CT-scanner appears to produce data useful for clinical imaging and 3D image processing.

  8. Population screening for colorectal cancer by flexible sigmoidoscopy or CT colonography: study protocol for a multicenter randomized trial

    PubMed Central

    2014-01-01

    Background Colorectal cancer (CRC) is the second most prevalent type of cancer in Europe. A single flexible sigmoidoscopy (FS) screening at around the age of 60 years prevents about one-third of CRC cases. However, FS screens only the distal colon, and thus mortality from proximal CRC is unaffected. Computed tomography colonography (CTC) is a highly accurate examination that allows assessment of the entire colon. However, the benefit of CTC testing as a CRC screening test is uncertain. We designed a randomized trial to compare participation rate, detection rates, and costs between CTC (with computer-aided detection) and FS as primary tests for population-based screening. Methods/Design An invitation letter to participate in a randomized screening trial comparing CTC versus FS will be mailed to a sample of 20,000 people aged 58 or 60 years, living in the Piedmont region and the Verona district of Italy. Individuals with a history of CRC, adenomas, inflammatory bowel disease, or recent colonoscopy, or with two first-degree relatives with CRC will be excluded from the study by their general practitioners. Individuals responding positively to the invitation letter will be then randomized to the intervention group (CTC) or control group (FS), and scheduled for the screening procedure. The primary outcome parameter of this part of the trial is the difference in advanced neoplasia detection between the two screening tests. Secondary outcomes are cost-effectiveness analysis, referral rates for colonoscopy induced by CTC versus FS, and the expected and perceived burden of the procedures. To compare participation rates for CTC versus FS, 2,000 additional eligible subjects will be randomly assigned to receive an invitation for screening with CTC or FS. In the CTC arm, non-responders will be offered fecal occult blood test (FOBT) as alternative screening test, while in the FS arm, non-responders will receive an invitation letter to undergo screening with either FOBT or CTC

  9. Population screening for colorectal cancer by flexible sigmoidoscopy or CT colonography: study protocol for a multicenter randomized trial.

    PubMed

    Regge, Daniele; Iussich, Gabriella; Senore, Carlo; Correale, Loredana; Hassan, Cesare; Bert, Alberto; Montemezzi, Stefania; Segnan, Nereo

    2014-03-28

    Colorectal cancer (CRC) is the second most prevalent type of cancer in Europe. A single flexible sigmoidoscopy (FS) screening at around the age of 60 years prevents about one-third of CRC cases. However, FS screens only the distal colon, and thus mortality from proximal CRC is unaffected. Computed tomography colonography (CTC) is a highly accurate examination that allows assessment of the entire colon. However, the benefit of CTC testing as a CRC screening test is uncertain. We designed a randomized trial to compare participation rate, detection rates, and costs between CTC (with computer-aided detection) and FS as primary tests for population-based screening. An invitation letter to participate in a randomized screening trial comparing CTC versus FS will be mailed to a sample of 20,000 people aged 58 or 60 years, living in the Piedmont region and the Verona district of Italy. Individuals with a history of CRC, adenomas, inflammatory bowel disease, or recent colonoscopy, or with two first-degree relatives with CRC will be excluded from the study by their general practitioners. Individuals responding positively to the invitation letter will be then randomized to the intervention group (CTC) or control group (FS), and scheduled for the screening procedure. The primary outcome parameter of this part of the trial is the difference in advanced neoplasia detection between the two screening tests. Secondary outcomes are cost-effectiveness analysis, referral rates for colonoscopy induced by CTC versus FS, and the expected and perceived burden of the procedures. To compare participation rates for CTC versus FS, 2,000 additional eligible subjects will be randomly assigned to receive an invitation for screening with CTC or FS. In the CTC arm, non-responders will be offered fecal occult blood test (FOBT) as alternative screening test, while in the FS arm, non-responders will receive an invitation letter to undergo screening with either FOBT or CTC. Data on reasons for

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

    PubMed

    Kim, Bohyun; Park, Seong Ho; Hong, Gil-Sun; Lee, Ju Hee; Lee, Jong Seok; Kim, Hyun Jin; Kim, Ah Young; Ha, Hyun Kwon

    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. • When used for tagging, iohexol caused significantly more colonic bubbles than diatrizoate. • The residual colonic fluid amount did not significantly differ between iohexol and diatrizoate. • The quality of fluid tagging was similarly adequate in both iohexol and diatrizoate.

  11. Automated 3D closed surface segmentation: application to vertebral body segmentation in CT images.

    PubMed

    Liu, Shuang; Xie, Yiting; Reeves, Anthony P

    2016-05-01

    A fully automated segmentation algorithm, progressive surface resolution (PSR), is presented in this paper to determine the closed surface of approximately convex blob-like structures that are common in biomedical imaging. The PSR algorithm was applied to the cortical surface segmentation of 460 vertebral bodies on 46 low-dose chest CT images, which can be potentially used for automated bone mineral density measurement and compression fracture detection. The target surface is realized by a closed triangular mesh, which thereby guarantees the enclosure. The surface vertices of the triangular mesh representation are constrained along radial trajectories that are uniformly distributed in 3D angle space. The segmentation is accomplished by determining for each radial trajectory the location of its intersection with the target surface. The surface is first initialized based on an input high confidence boundary image and then resolved progressively based on a dynamic attraction map in an order of decreasing degree of evidence regarding the target surface location. For the visual evaluation, the algorithm achieved acceptable segmentation for 99.35 % vertebral bodies. Quantitative evaluation was performed on 46 vertebral bodies and achieved overall mean Dice coefficient of 0.939 (with max [Formula: see text] 0.957, min [Formula: see text] 0.906 and standard deviation [Formula: see text] 0.011) using manual annotations as the ground truth. Both visual and quantitative evaluations demonstrate encouraging performance of the PSR algorithm. This novel surface resolution strategy provides uniform angular resolution for the segmented surface with computation complexity and runtime that are linearly constrained by the total number of vertices of the triangular mesh representation.

  12. Effect of voxel size on 3D micro-CT analysis of cortical bone porosity.

    PubMed

    Cooper, David; Turinsky, Andrei; Sensen, Christoph; Hallgrimsson, Benedikt

    2007-03-01

    This study examines the impact of voxel size on 3D micro-CT analysis of human cortical bone porosity. The study is based on computed microtomography scans of 10 human anterior femoral midshaft specimens acquired at 5, 10, and 15 microm voxel sizes. Artificial voxel sizes (10, 20, and 40 microm) were generated from the smallest scan voxel size (5 microm) in order to compare actual scanning with artificial degradation, a method employed in other similar studies. Canal volume fraction (CaV/TV), canal surface to volume ratio (CaS/CaV), mean canal diameter (CaDm), mean canal separation (CaSp), canal number (CaN), degree of anisotropy (DA), and canal connectivity density (CaConnD) were calculated from matching volumes of interest for all datasets. Qualitatively, the clarity of the actual scan datasets deteriorated rapidly as voxel size increased. In contrast, within the artificially generated datasets, the clarity of cortical pores was better maintained until the largest voxel size (40 microm). Mean absolute percent error values, correlation coefficients, and paired t-tests revealed a pattern of increasing, and generally significant, differences between the smallest and progressively larger voxel sizes (both scanned and artificial). Relative to the actual scans, however, the artificial datasets were less sensitive to changing voxel size. These findings indicated that subtle changes in voxel size, within the range examined, have a considerable effect on human cortical porosity structural parameters. Additionally, the use of artificially increased voxel sizes should be viewed with caution as they may not reflect what can actually be obtained by scanning.

  13. Efficient 3D finite element analysis of dental restorative procedures using micro-CT data.

    PubMed

    Magne, Pascal

    2007-05-01

    This investigation describes a rapid method for the generation of finite element models of dental structures and restorations. An intact mandibular molar was digitized with a micro-CT scanner. Surface contours of enamel and dentin were fitted following tooth segmentation based on pixel density using an interactive medical image control system. Stereolithography (STL) files of enamel and dentin surfaces were then remeshed to reduce mesh density and imported in a rapid prototyping software, where Boolean operations were used to assure the interfacial mesh congruence (dentinoenamel junction) and simulate different cavity preparations (MO/MOD preparations, endodontic access) and restorations (feldspathic porcelain and composite resin inlays). The different tooth parts were then imported in a finite element software package to create 3D solid models. The potential use of the model was demonstrated using nonlinear contact analysis to simulate occlusal loading. Cuspal deformation was measured at different restorative steps and correlated with existing experimental data for model validation and optimization. Five different models were validated by existing experimental data. Cuspal widening (between mesial cusps) at 100 N load ranged from 0.4 microm for the unrestored tooth, 9-12 microm for MO, MOD cavities, to 12-21 microm for endodontic access cavities. Placement of an MOD adhesive restoration in porcelain resulted in 100% cuspal stiffness recovery (0.4 microm of cuspal widening at 100 N) while the composite resin inlay allowed for a partial recuperation of cusp stabilization (1.3 microm of cuspal widening at 100 N). The described method can generate detailed and valid three dimensional finite element models of a molar tooth with different cavities and restorative materials. This method is rapid and can readily be used for other medical (and dental) applications.

  14. Clinical significance of creative 3D-image fusion across multimodalities [PET+CT+MR] based on characteristic coregistration.

    PubMed

    Peng, Matthew Jian-qiao; Ju, Xiangyang; Khambay, Balvinder S; Ayoub, Ashraf F; Chen, Chin-Tu; Bai, Bo

    2012-03-01

    To investigate a registration approach for 2-dimension (2D) based on characteristic localization to achieve 3-dimension (3D) fusion from images of PET, CT and MR one by one. A cubic oriented scheme of"9-point & 3-plane" for co-registration design was verified to be geometrically practical. After acquisiting DICOM data of PET/CT/MR (directed by radiotracer 18F-FDG etc.), through 3D reconstruction and virtual dissection, human internal feature points were sorted to combine with preselected external feature points for matching process. By following the procedure of feature extraction and image mapping, "picking points to form planes" and "picking planes for segmentation" were executed. Eventually, image fusion was implemented at real-time workstation mimics based on auto-fuse techniques so called "information exchange" and "signal overlay". The 2D and 3D images fused across modalities of [CT+MR], [PET+MR], [PET+CT] and [PET+CT+MR] were tested on data of patients suffered from tumors. Complementary 2D/3D images simultaneously presenting metabolic activities and anatomic structures were created with detectable-rate of 70%, 56%, 54% (or 98%) and 44% with no significant difference for each in statistics. Currently, based on the condition that there is no complete hybrid detector integrated of triple-module [PET+CT+MR] internationally, this sort of multiple modality fusion is doubtlessly an essential complement for the existing function of single modality imaging. Crown Copyright © 2012. Published by Elsevier Ireland Ltd. All rights reserved.

  15. [Analysis and discussion on the facet of the spinal column, spiral CT lock multiplanar reconstruction and 
3D reconstruction].

    PubMed

    Zheng, Zhifeng; Wang, Shuhang; Si, Donglei

    2015-10-01

    To investigate the imaging appearances and diagnostic value of axial CT scanning, spiral CT multiplanar reconstruction (MPR) and three-dimensional (3D) reconstruction in vertebral facet joints locking.
 A total of 31 cases of vertebral facet joints locking, with injuries in different parts, were recruited to explore their CT features, and to evaluate their advantages in diagnosis against each other.
 Among the CT images of 31 cases with "Hamburger" sign in axial view, there were 21 cases of cervical spine and 10 cases of thoracolumbar segment; in vertical plane of MPR, "top to top" form was formed below the inferior and the superior articular process, accompanied by I° spondylolisthesis and inferior articular process tip fracture; 5 cases were unilateral locked cervical spine; none case for thoracolumbar segment. The inferior articular process was crossed with the superior articular process below and moved forward, formed "back to back" form, accompanied by II°-III° spondylolisthesis. 9 or 6 cases were bilateral or unilateral locking cervical spine, 10 cases were thoracolumbar segment, accompanied by teardrop fracture in the vertebral body below cervical spine. In coronal plane of MPR, inferior articular process showed ingression in different extent, and relied on the superior articular process below or locked in the articular fossa (21 cases for cervical spine); inferior articular process displayed upward displacement or appeared with the superior articular process at the same time, which meant joint structure disappearing thoracolumbar segment (10 cases). In 3D reconstruction, 31 cases displayed clearly in the spatial form of vertebral facet joints locking and the degree of spondylolisthesis of vertebral body.
 MPR and 3D image were more clear and intuitive in vertebral facet joints locking comparing to axial CT scan image. Spiral CT MPR and 3D reconstruction contributed to the diagnosis of vertebral facet joints locking and the reduction of misdiagnoses

  16. Cost-effectiveness of computerized tomographic colonography versus colonoscopy for colorectal cancer screening

    PubMed Central

    Heitman, Steven J.; Manns, Braden J.; Hilsden, Robert J.; Fong, Andrew; Dean, Stafford; Romagnuolo, Joseph

    2005-01-01

    Background Computerized tomographic (CT) colonography is a potential alternative to colonoscopy for colorectal cancer screening. Its main advantage, a better safety profile, may be offset by its limitations: lower sensitivity, need for colonoscopy in cases where results are positive, and expense. Methods We performed an economic evaluation, using decision analysis, to compare CT colonography with colonoscopy for colorectal cancer screening in patients over 50 years of age. Three-year outcomes included number of colonoscopies, perforations and adenomas removed; deaths from perforation and from colorectal cancer from missed adenomas; and direct health care costs. The expected prevalence of adenomas, test performance characteristics of CT colonography and colonoscopy, and probability of colonoscopy complications and cancer from missed adenomas were derived from the literature. Costs were determined in detail locally. Results Using the base-case assumptions, a strategy of CT colonography for colorectal cancer screening would cost $2.27 million extra per 100 000 patients screened; 3.78 perforation-related deaths would be avoided, but 4.11 extra deaths would occur from missed adenomas. Because screening with CT colonography would cost more and result in more deaths overall compared with colonoscopy, the latter remained the dominant strategy. Our results were sensitive to CT colonography's test performance characteristics, the malignant risk of missed adenomas, the risk of perforation and related death, the procedural costs and differences in screening adherence. Interpretation At present, CT colonography cannot be recommended as a primary means of population-based colorectal cancer screening in Canada. PMID:16217110

  17. µCT-3D visualization analysis of resin composite polymerization and dye penetration test of composite adaptation.

    PubMed

    Yoshikawa, Takako; Sadr, Alireza; Tagami, Junji

    2017-08-25

    This study evaluated the effects of the light curing methods and resin composite composition on composite polymerization contraction behavior and resin composite adaptation to the cavity wall using μCT-3D visualization analysis and dye penetration test. Cylindrical cavities were restored using Clearfil tri-S Bond ND Quick adhesive and filled with Clearfil AP-X or Clearfil Photo Bright composite. The composites were cured using the conventional or the slow-start curing method. The light-cured resin composite, which had increased contrast ratio during polymerization, improved adaptation to the cavity wall using the slow-start curing method. In the μCT-3D visualization method, the slow-start curing method reduced polymerization shrinkage volume of resin composite restoration to half of that produced by the conventional curing method in the cavity with adhesive for both composites. Moreover, μCT-3D visualization method can be used to detect and analyze resin composite polymerization contraction behavior and shrinkage volume as 3D image in the cavity.

  18. [Brain 3 D-CT angiography was a useful tool for diagnosis of internal carotid-posterior communicating artery aneurysm: a case of false negative 3 D-MRA].

    PubMed

    Ikeda, K; Iwasaki, Y; Murakami, S; Ichikawa, Y

    1999-09-01

    A 75-year-old woman with hypertension suddenly developed ptosis in the left eyelid. Neurological examination revealed left oculomotor nerve palsy. Brain T 2-weighted imaging showed abnormal flow void sign in the proximal portion of left middle cerebral artery. Other MRIs, including gadolinium enhancement, were normal. However, brain 3 D-MRA, using time-of-flight sequence, did not disclose any intracranial aneurysms. 3 D-CT angiography revealed left internal carotid-posterior communicating artery (IC-PC) aneurysm. Maximum intensity projection display of CT angiography demonstrated the neck and head portions of IC-PC aneurysm (size = 8 mm). Furthermore, 3 D-CT angiography was beneficial for anatomical evaluation of the aneurysm and the surrounding bony structures. The false negative 3 D-MRA of our patient was thought to result from flow-related artifacts, slow blood flow in the aneurysm, the surrounding noise and the localization of aneurysm. False negative findings of cerebral aneurysms occasionally occur on 3 D-MRA or 3 D-CT angiography, in comparison with digital subtraction angiography. Thus, we should pay more attention to assessment of 3 D-MRA and 3 D-CT angiography in patients who have high risks of cerebral aneurysms.

  19. 3D motion artifact compenstation in CT image with depth camera

    NASA Astrophysics Data System (ADS)

    Ko, Youngjun; Baek, Jongduk; Shim, Hyunjung

    2015-02-01

    Computed tomography (CT) is a medical imaging technology that projects computer-processed X-rays to acquire tomographic images or the slices of specific organ of body. A motion artifact caused by patient motion is a common problem in CT system and may introduce undesirable artifacts in CT images. This paper analyzes the critical problems in motion artifacts and proposes a new CT system for motion artifact compensation. We employ depth cameras to capture the patient motion and account it for the CT image reconstruction. In this way, we achieve the significant improvement in motion artifact compensation, which is not possible by previous techniques.

  20. Efficient 3D rigid-body registration of micro-MR and micro-CT trabecular bone images

    NASA Astrophysics Data System (ADS)

    Rajapakse, C. S.; Magland, J.; Wehrli, S. L.; Zhang, X. H.; Liu, X. S.; Guo, X. E.; Wehrli, F. W.

    2008-03-01

    Registration of 3D images acquired from different imaging modalities such as micro-magnetic resonance imaging (µMRI) and micro-computed tomography (µCT) are of interest in a number of medical imaging applications. Most general-purpose multimodality registration algorithms tend to be computationally intensive and do not take advantage of the shape of the imaging volume. Multimodality trabecular bone (TB) images of cylindrical cores, for example, tend to be misaligned along and around the axial direction more than that around other directions. Additionally, TB images acquired by µMRI can differ substantially from those acquired by µCT due to apparent trabecular thickening from magnetic susceptibility boundary effects and non-linear intensity correspondence. However, they share very similar contrast characteristics since the images essentially represent a binary tomographic system. The directional misalignment and the fundamental similarities of the two types of images can be exploited to achieve fast 3D registration. Here we present an intensity cross-correlation based 3D registration algorithm for registering 3D specimen images from cylindrical cores of cadaveric TB acquired by µMRI and µCT in the context of finite-element modeling to assess the bone's mechanical constants. The algorithm achieves the desired registration by first coarsely approximating the three translational and three rotational parameters required to align the µMR images to the µCT scan coordinate frame and fine-tuning the parameters in the neighborhood of the approximate solution. The algorithm described here is suitable for 3D rigid-body image registration applications where through-plane rotations are known to be relatively small. The accuracy of the technique is constrained by the image resolution and in-plane angular increments used.

  1. Noninvasive CT to Iso-C3D registration for improved intraoperative visualization in computer assisted orthopedic surgery

    NASA Astrophysics Data System (ADS)

    Rudolph, Tobias; Ebert, Lars; Kowal, Jens

    2006-03-01

    Supporting surgeons in performing minimally invasive surgeries can be considered as one of the major goals of computer assisted surgery. Excellent intraoperative visualization is a prerequisite to achieve this aim. The Siremobil Iso-C 3D has become a widely used imaging device, which, in combination with a navigation system, enables the surgeon to directly navigate within the acquired 3D image volume without any extra registration steps. However, the image quality is rather low compared to a CT scan and the volume size (approx. 12 cm 3) limits its application. A regularly used alternative in computer assisted orthopedic surgery is to use of a preoperatively acquired CT scan to visualize the operating field. But, the additional registration step, necessary in order to use CT stacks for navigation is quite invasive. Therefore the objective of this work is to develop a noninvasive registration technique. In this article a solution is being proposed that registers a preoperatively acquired CT scan to the intraoperatively acquired Iso-C 3D image volume, thereby registering the CT to the tracked anatomy. The procedure aligns both image volumes by maximizing the mutual information, an algorithm that has already been applied to similar registration problems and demonstrated good results. Furthermore the accuracy of such a registration method was investigated in a clinical setup, integrating a navigated Iso-C 3D in combination with an tracking system. Initial tests based on cadaveric animal bone resulted in an accuracy ranging from 0.63mm to 1.55mm mean error.

  2. A novel 3D-printed phantom insert for 4D PET/CT imaging and simultaneous integrated boost radiotherapy.

    PubMed

    Cerviño, Laura; Soultan, Dima; Cornell, Mariel; Yock, Adam; Pettersson, Niclas; Song, William Y; Aguilera, Joseph; Advani, Sunil; Murphy, James; Hoh, Carl; James, Claude; Paravati, Anthony; Coope, Robin; Gill, Bradford; Moiseenko, Vitali

    2017-10-01

    To construct a 3D-printed phantom insert designed to mimic the variable PET tracer uptake seen in lung tumor volumes and a matching dosimetric insert to be used in simultaneous integrated boost (SIB) phantom studies, and to evaluate the design through end-to-end tests. A set of phantom inserts was designed and manufactured for a realistic representation of gated radiotherapy steps from 4D PET/CT scanning to dose delivery. A cylindrical phantom (φ80 × 120 mm) holds inserts for PET/CT scanning. The novel 3D printed insert dedicated to 4D PET/CT mimics high PET tracer uptake in the core and low uptake in the periphery. This insert is a variable density porous cylinder (φ44.5 × 70.0 mm), ABS-P430 thermoplastic, 3D printed by fused deposition modeling an inner (φ11 × 42 mm) cylindrical void. The square pores (1.8 × 1.8 mm(2) each) fill 50% of outer volume, resulting in a 2:1 PET tracer concentration ratio in the void volume with respect to porous volume. A matching cylindrical phantom insert is dedicated to validate gated radiotherapy. It contains eight peripheral holes and one central hole, matching the location of the porous part and the void part of the 3D printed insert, respectively. These holes accommodate adaptors for Farmer-type ion chamber and cells vials. End-to-end tests were designed for imaging, planning, and dose measurements. End-to-end test were performed from 4D PET/CT scanning to transferring data to the planning system, target volume delineation, and dose measurements. 4D PET/CT scans were acquired of the phantom at different respiratory motion patterns and gating windows. A measured 2:1 18F-FDG concentration ratio between inner void and outer porous volume matched the 3D printed design. Measured dose in the dosimetric insert agreed well with planned dose on the imaging insert, within 3% for the static phantom and within 5% for most breathing patterns. The novel 3D printed phantom insert mimics variable PET tracer uptake typical of tumors

  3. US-CT 3D dual imaging by mutual display of the same sections for depicting minor changes in hepatocellular carcinoma.

    PubMed

    Fukuda, Hiroyuki; Ito, Ryu; Ohto, Masao; Sakamoto, Akio; Otsuka, Masayuki; Togawa, Akira; Miyazaki, Masaru; Yamagata, Hitoshi

    2012-09-01

    The purpose of this study was to evaluate the usefulness of ultrasound-computed tomography (US-CT) 3D dual imaging for the detection of small extranodular growths of hepatocellular carcinoma (HCC). The clinical and pathological profiles of 10 patients with single nodular type HCC with extranodular growth (extranodular growth) who underwent a hepatectomy were evaluated using two-dimensional (2D) ultrasonography (US), three-dimensional (3D) US, 3D computed tomography (CT) and 3D US-CT dual images. Raw 3D data was converted to DICOM (Digital Imaging and Communication in Medicine) data using Echo to CT (Toshiba Medical Systems Corp., Tokyo, Japan), and the 3D DICOM data was directly transferred to the image analysis system (ZioM900, ZIOSOFT Inc., Tokyo, Japan). By inputting the angle number (x, y, z) of the 3D CT volume data into the ZioM900, multiplanar reconstruction (MPR) images of the 3D CT data were displayed in a manner such that they resembled the conventional US images. Eleven extranodular growths were detected pathologically in 10 cases. 2D US was capable of depicting only 2 of the 11 extranodular growths. 3D CT was capable of depicting 4 of the 11 extranodular growths. On the other hand, 3D US was capable of depicting 10 of the 11 extranodular growths, and 3D US-CT dual images, which enable the dual analysis of the CT and US planes, revealed all 11 extranodular growths. In conclusion, US-CT 3D dual imaging may be useful for the detection of small extranodular growths.

  4. Self-calibration of cone-beam CT geometry using 3D-2D image registration.

    PubMed

    Ouadah, S; Stayman, J W; Gang, G J; Ehtiati, T; Siewerdsen, J H

    2016-04-07

    Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a 'self-calibration' of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM-e.g. on the CBCT bench, FWHM  =  0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p  <  0.001). Similar improvements were measured in RPE-e.g. on the robotic C-arm, RPE  =  0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p  <  0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is

  5. Self-calibration of cone-beam CT geometry using 3D-2D image registration

    NASA Astrophysics Data System (ADS)

    Ouadah, S.; Stayman, J. W.; Gang, G. J.; Ehtiati, T.; Siewerdsen, J. H.

    2016-04-01

    Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a ‘self-calibration’ of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM—e.g. on the CBCT bench, FWHM  =  0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p  <  0.001). Similar improvements were measured in RPE—e.g. on the robotic C-arm, RPE  =  0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p  <  0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is

  6. 3D image analysis of plants using electron tomography and micro-CT.

    PubMed

    Mineyuki, Yoshinobu

    2014-11-01

    help to promote MT bundling. Cell plate attachment to the parental wall leads to the fusion of the newly formed middle lamellae in the cell plate to the middle lamella of parental cell wall, and a three-way junction is created. Air space develops from the three-way junction. To determine 3D arrangement of cells and air spaces, we used X-ray micro-CT at the SPring-8 synchrotron radiation facility. Using micro-CT available in BL20XU (8 keV, 0.2 µm/pixel), we were able to elucidate ∼90% of the cortical cell outlines in the hypocotyl-radicle axis of arabidopsis seeds [4] and to analyze cell geometrical properties. As the strength of the system X-ray is too strong for seed survival, we used another beam line BL20B2 (10-15 keV, 2.4-2.7 µm/pixel) to examine air space development during seed imbibition [4,5]. Using this system, we were able to detect air space development at the early imbibition stages of seeds without causing damage during seed germination. AcknowledgmentThe author would like to thank Dr. Ichirou Karahara (Univ. Toyama), Dr. L. Andrew Staehelin (Univ. Colorado), Ms. Naoko Kajimura, Dr. Akio Takaoka (Osaka Univ.), Dr. Kazuyo Misaki, Dr. Shigenobu Yonemura (RIKEN CDB), Dr. Kazuyoshi Murata (NIP), Dr. Kentaro Uesugi, Dr. Akihisa Takeuchi, Dr. Yoshio Suzuki (JASRI), Dr. Miyuki Takeuchi, Dr. Daisuke Tamaoki, Dr. Daisuke Yamauchi, and Ms. Aki Fukuda (Univ. Hyogo) for their collaborations in the work presented here. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. CT Image Sequence Analysis for Object Recognition - A Rule-Based 3-D Computer Vision System

    Treesearch

    Dongping Zhu; Richard W. Conners; Daniel L. Schmoldt; Philip A. Araman

    1991-01-01

    Research is now underway to create a vision system for hardwood log inspection using a knowledge-based approach. In this paper, we present a rule-based, 3-D vision system for locating and identifying wood defects using topological, geometric, and statistical attributes. A number of different features can be derived from the 3-D input scenes. These features and evidence...

  8. Construction of Realistic Liver Phantoms from Patient Images using 3D Printer and Its Application in CT Image Quality Assessment

    PubMed Central

    Leng, Shuai; Yu, Lifeng; Vrieze, Thomas; Kuhlmann, Joel; Chen, Baiyu; McCollough, Cynthia H.

    2016-01-01

    The purpose of this study is to use 3D printing techniques to construct a realistic liver phantom with heterogeneous background and anatomic structures from patient CT images, and to use the phantom to assess image quality with filtered backprojection and iterative reconstruction algorithms. Patient CT images were segmented into liver tissues, contrast-enhanced vessels, and liver lesions using commercial software, based on which stereolithography (STL) files were created and sent to a commercial 3D printer. A 3D liver phantom was printed after assigning different printing materials to each object to simulate appropriate attenuation of each segmented object. As high opacity materials are not available for the printer, we printed hollow vessels and filled them with iodine solutions of adjusted concentration to represent enhance levels in contrast-enhanced liver scans. The printed phantom was then placed in a 35×26 cm oblong-shaped water phantom and scanned repeatedly at 4 dose levels. Images were reconstructed using standard filtered backprojection and an iterative reconstruction algorithm with 3 different strength settings. Heterogeneous liver background were observed from the CT images and the difference in CT numbers between lesions and background were representative for low contrast lesions in liver CT studies. CT numbers in vessels filled with iodine solutions represented the enhancement of liver arteries and veins. Images were run through a Channelized Hotelling model observer with Garbor channels and ROC analysis was performed. The AUC values showed performance improvement using the iterative reconstruction algorithm and the amount of improvement increased with strength setting. PMID:27721555

  9. Construction of Realistic Liver Phantoms from Patient Images using 3D Printer and Its Application in CT Image Quality Assessment.

    PubMed

    Leng, Shuai; Yu, Lifeng; Vrieze, Thomas; Kuhlmann, Joel; Chen, Baiyu; McCollough, Cynthia H

    2015-01-01

    The purpose of this study is to use 3D printing techniques to construct a realistic liver phantom with heterogeneous background and anatomic structures from patient CT images, and to use the phantom to assess image quality with filtered backprojection and iterative reconstruction algorithms. Patient CT images were segmented into liver tissues, contrast-enhanced vessels, and liver lesions using commercial software, based on which stereolithography (STL) files were created and sent to a commercial 3D printer. A 3D liver phantom was printed after assigning different printing materials to each object to simulate appropriate attenuation of each segmented object. As high opacity materials are not available for the printer, we printed hollow vessels and filled them with iodine solutions of adjusted concentration to represent enhance levels in contrast-enhanced liver scans. The printed phantom was then placed in a 35×26 cm oblong-shaped water phantom and scanned repeatedly at 4 dose levels. Images were reconstructed using standard filtered backprojection and an iterative reconstruction algorithm with 3 different strength settings. Heterogeneous liver background were observed from the CT images and the difference in CT numbers between lesions and background were representative for low contrast lesions in liver CT studies. CT numbers in vessels filled with iodine solutions represented the enhancement of liver arteries and veins. Images were run through a Channelized Hotelling model observer with Garbor channels and ROC analysis was performed. The AUC values showed performance improvement using the iterative reconstruction algorithm and the amount of improvement increased with strength setting.

  10. Construction of realistic liver phantoms from patient images using 3D printer and its application in CT image quality assessment

    NASA Astrophysics Data System (ADS)

    Leng, Shuai; Yu, Lifeng; Vrieze, Thomas; Kuhlmann, Joel; Chen, Baiyu; McCollough, Cynthia H.

    2015-03-01

    The purpose of this study is to use 3D printing techniques to construct a realistic liver phantom with heterogeneous background and anatomic structures from patient CT images, and to use the phantom to assess image quality with filtered back-projection and iterative reconstruction algorithms. Patient CT images were segmented into liver tissues, contrast-enhanced vessels, and liver lesions using commercial software, based on which stereolithography (STL) files were created and sent to a commercial 3D printer. A 3D liver phantom was printed after assigning different printing materials to each object to simulate appropriate attenuation of each segmented object. As high opacity materials are not available for the printer, we printed hollow vessels and filled them with iodine solutions of adjusted concentration to represent enhance levels in contrast-enhanced liver scans. The printed phantom was then placed in a 35×26 cm oblong-shaped water phantom and scanned repeatedly at 4 dose levels. Images were reconstructed using standard filtered back-projection and an iterative reconstruction algorithm with 3 different strength settings. Heterogeneous liver background were observed from the CT images and the difference in CT numbers between lesions and background were representative for low contrast lesions in liver CT studies. CT numbers in vessels filled with iodine solutions represented the enhancement of liver arteries and veins. Images were run through a Channelized Hotelling model observer with Garbor channels and ROC analysis was performed. The AUC values showed performance improvement using the iterative reconstruction algorithm and the amount of improvement increased with strength setting.

  11. A Registration Method Based on Contour Point Cloud for 3D Whole-Body PET and CT Images

    PubMed Central

    Yang, Qiyao; Wang, Zhiguo; Zhang, Guoxu

    2017-01-01

    The PET and CT fusion image, combining the anatomical and functional information, has important clinical meaning. An effective registration of PET and CT images is the basis of image fusion. This paper presents a multithread registration method based on contour point cloud for 3D whole-body PET and CT images. Firstly, a geometric feature-based segmentation (GFS) method and a dynamic threshold denoising (DTD) method are creatively proposed to preprocess CT and PET images, respectively. Next, a new automated trunk slices extraction method is presented for extracting feature point clouds. Finally, the multithread Iterative Closet Point is adopted to drive an affine transform. We compare our method with a multiresolution registration method based on Mattes Mutual Information on 13 pairs (246~286 slices per pair) of 3D whole-body PET and CT data. Experimental results demonstrate the registration effectiveness of our method with lower negative normalization correlation (NC = −0.933) on feature images and less Euclidean distance error (ED = 2.826) on landmark points, outperforming the source data (NC = −0.496, ED = 25.847) and the compared method (NC = −0.614, ED = 16.085). Moreover, our method is about ten times faster than the compared one. PMID:28316979

  12. Regularization Designs for Uniform Spatial Resolution and Noise Properties in Statistical Image Reconstruction for 3D X-ray CT

    PubMed Central

    Cho, Jang Hwan; Fessler, Jeffrey A.

    2014-01-01

    Statistical image reconstruction methods for X-ray computed tomography (CT) provide improved spatial resolution and noise properties over conventional filtered back-projection (FBP) reconstruction, along with other potential advantages such as reduced patient dose and artifacts. Conventional regularized image reconstruction leads to spatially variant spatial resolution and noise characteristics because of interactions between the system models and the regularization. Previous regularization design methods aiming to solve such issues mostly rely on circulant approximations of the Fisher information matrix that are very inaccurate for undersampled geometries like short-scan cone-beam CT. This paper extends the regularization method proposed in [1] to 3D cone-beam CT by introducing a hypothetical scanning geometry that helps address the sampling properties. The proposed regularization designs were compared with the original method in [1] with both phantom simulation and clinical reconstruction in 3D axial X-ray CT. The proposed regularization methods yield improved spatial resolution or noise uniformity in statistical image reconstruction for short-scan axial cone-beam CT. PMID:25361500

  13. Quantitative 3D micro-CT imaging of the human feto-placental vasculature in intrauterine growth restriction.

    PubMed

    Langheinrich, A C; Vorman, S; Seidenstücker, J; Kampschulte, M; Bohle, R M; Wienhard, J; Zygmunt, M

    2008-11-01

    Placental vascular development matches fetal growth and development. Quantification of the feto-placental vasculature in placentas from pregnancies is complicated by intrauterine growth restriction (IUGR) revealed confounding results. Therefore, the feto-placental vascular volume in IUGR placentas was assessed by 3D micro-computed tomography (micro-CT). Placental probes from IUGR (n=24) and healthy control placentas (n=40) were perfused in situ with Microfil or BaSO(4) and randomly chosen samples were scanned by micro-CT. Using 3D images, we quantitated the feto-placental vascular volume fraction (VVF). A subanalysis was performed at three different levels, reaching from the chorionic plate artery (level A), to intermediate arteries (level B) and capillary system (level C). Results were complemented by histology. The significance of differences in vascular volume measurements was tested with analysis of variance [ANOVA]. Microfil perfused placentas showed a total vascular volume fraction of 20.5+/-0.9% in healthy controls. In contrast, the VVF decreased to 7.9+/-0.9% (p<0.001) in IUGR placentas. Significant differences were found between Microfil and BaSO(4) perfused placentas in the vascular volume fraction using micro-CT and histology. Micro-CT demonstrated localized concentric luminal encroachments in the intermediate arteries in placentas complicated by IUGR. Micro-CT imaging is feasible for quantitative analysis of the feto-placental vascular tree in healthy controls and pregnancies complicated by IUGR.

  14. Regularization designs for uniform spatial resolution and noise properties in statistical image reconstruction for 3-D X-ray CT.

    PubMed

    Cho, Jang Hwan; Fessler, Jeffrey A

    2015-02-01

    Statistical image reconstruction methods for X-ray computed tomography (CT) provide improved spatial resolution and noise properties over conventional filtered back-projection (FBP) reconstruction, along with other potential advantages such as reduced patient dose and artifacts. Conventional regularized image reconstruction leads to spatially variant spatial resolution and noise characteristics because of interactions between the system models and the regularization. Previous regularization design methods aiming to solve such issues mostly rely on circulant approximations of the Fisher information matrix that are very inaccurate for undersampled geometries like short-scan cone-beam CT. This paper extends the regularization method proposed in to 3-D cone-beam CT by introducing a hypothetical scanning geometry that helps address the sampling properties. The proposed regularization designs were compared with the original method in with both phantom simulation and clinical reconstruction in 3-D axial X-ray CT. The proposed regularization methods yield improved spatial resolution or noise uniformity in statistical image reconstruction for short-scan axial cone-beam CT.

  15. Virtual animation of victim-specific 3D models obtained from CT scans for forensic reconstructions: Living and dead subjects.

    PubMed

    Villa, C; Olsen, K B; Hansen, S H

    2017-09-01

    Post-mortem CT scanning (PMCT) has been introduced at several forensic medical institutions many years ago and has proved to be a useful tool. 3D models of bones, skin, internal organs and bullet paths can rapidly be generated using post-processing software. These 3D models reflect the individual physiognomics and can be used to create whole-body 3D virtual animations. In such way, virtual reconstructions of the probable ante-mortem postures of victims can be constructed and contribute to understand the sequence of events. This procedure is demonstrated in two victims of gunshot injuries. Case #1 was a man showing three perforating gunshot wounds, who died due to the injuries of the incident. Whole-body PMCT was performed and 3D reconstructions of bones, relevant internal organs and bullet paths were generated. Using 3ds Max software and a human anatomy 3D model, a virtual animated body was built and probable ante-mortem postures visualized. Case #2 was a man presenting three perforating gunshot wounds, who survived the incident: one in the left arm and two in the thorax. Only CT scans of the thorax, abdomen and the injured arm were provided by the hospital. Therefore, a whole-body 3D model reflecting the anatomical proportions of the patient was made combining the actual bones of the victim with those obtained from the human anatomy 3D model. The resulted 3D model was used for the animation process. Several probable postures were also visualized in this case. It has be shown that in Case #1 the lesions and the bullet path were not consistent with an upright standing position; instead, the victim was slightly bent forward, i.e. he was sitting or running when he was shot. In Case #2, one of the bullets could have passed through the arm and continued into the thorax. In conclusion, specialized 3D modelling and animation techniques allow for the reconstruction of ante-mortem postures based on both PMCT and clinical CT. Copyright © 2017 Elsevier B.V. All rights

  16. Non-rigid registration of small animal skeletons from micro-CT using 3D shape context

    NASA Astrophysics Data System (ADS)

    Xiao, Di; Bourgeat, Pierrick; Fripp, Jurgen; Acosta Tamayo, Oscar; Gregoire, Marie Claude; Salvado, Olivier

    2009-02-01

    Small animal registration is an important step for molecular image analysis. Skeleton registration from whole-body or only partial micro Computerized Tomography (CT) image is often performed to match individual rats to atlases and templates, for example to identify organs in positron emission tomography (PET). In this paper, we extend the shape context matching technique for 3D surface registration and apply it for rat hind limb skeleton registration from CT images. Using the proposed method, after standard affine iterative closest point (ICP) registration, correspondences between the 3D points from sour and target objects were robustly found and used to deform the limb skeleton surface with thin-plate-spline (TPS). Experiments are described using phantoms and actual rat hind limb skeletons. On animals, mean square errors were decreased by the proposed registration compared to that of its initial alignment. Visually, skeletons were successfully registered even in cases of very different animal poses.

  17. Precise 3D dimensional metrology using high-resolution x-ray computed tomography (μCT)

    NASA Astrophysics Data System (ADS)

    Brunke, Oliver; Santillan, Javier; Suppes, Alexander

    2010-09-01

    Over the past decade computed tomography (CT) with conventional x-ray sources has evolved from an imaging method in medicine to a well established technology for industrial applications in fields such as material science, light metals and plastics processing, microelectronics and geology. By using modern microfocus and nanofocus X-ray tubes, parts can be scanned with sub-micrometer resolutions. Currently, micro-CT is a technology increasingly used for metrology applications in the automotive industry. CT offers big advantages compared with conventional tactile or optical coordinate measuring machines (CMMs). This is of greater importance if complex parts with hidden or difficult accessible surfaces have to be measured. In these cases, CT offers the advantage of a high density of measurement points and a non-destructive and fast capturing of the sample's complete geometry. When using this growing technology the question arises how precise a μCT based CMM can measure as compared to conventional and established methods for coordinate measurements. For characterizing the metrological capabilities of a tactile or optical CMM, internationally standardized parameters like length measurement error and probing error are defined and used. To increase the acceptance of CT as a metrological method, our work seeks to clarify the definition and usage of parameters used in the field of metrology as these apply to CT. In this paper, an overview of the process chain in CT based metrology will be given and metrological characteristics will be described. For the potential user of CT as 3D metrology tool it is important to show the measurement accuracy and repeatability on realistic samples. Following a discussion of CT metrology techniques, two samples are discussed. The first compares a measured CT Data set to CAD data using CMM data as a standard for comparison of results. The second data second realistic data set will compare the results of applying both the CMM method of

  18. Combining 2D wavelet edge highlighting and 3D thresholding for lung segmentation in thin-slice CT.

    PubMed

    Korfiatis, P; Skiadopoulos, S; Sakellaropoulos, P; Kalogeropoulou, C; Costaridou, L

    2007-12-01

    The first step in lung analysis by CT is the identification of the lung border. To deal with the increased number of sections per scan in thin-slice multidetector CT, it has been crucial to develop accurate and automated lung segmentation algorithms. In this study, an automated method for lung segmentation of thin-slice CT data is presented. The method exploits the advantages of a two-dimensional wavelet edge-highlighting step in lung border delineation. Lung volume segmentation is achieved with three-dimensional (3D) grey level thresholding, using a minimum error technique. 3D thresholding, combined with the wavelet pre-processing step, successfully deals with lung border segmentation challenges, such as anterior or posterior junction lines and juxtapleural nodules. Finally, to deal with mediastinum border under-segmentation, 3D morphological closing with a spherical structural element is applied. The performance of the proposed method is quantitatively assessed on a dataset originating from the Lung Imaging Database Consortium (LIDC) by comparing automatically derived borders with the manually traced ones. Segmentation performance, averaged over left and right lung volumes, for lung volume overlap is 0.983+/-0.008, whereas for shape differentiation in terms of mean distance it is 0.770+/-0.251 mm (root mean square distance is 0.520+/-0.008 mm; maximum distance is 3.327+/-1.637 mm). The effect of the wavelet pre-processing step was assessed by comparing the proposed method with the 3D thresholding technique (applied on original volume data). This yielded statistically significant differences for all segmentation metrics (p<0.01). Results demonstrate an accurate method that could be used as a first step in computer lung analysis by CT.

  19. 3D electron density imaging using single scattered x rays with application to breast CT and mammographic screening

    NASA Astrophysics Data System (ADS)

    van Uytven, Eric Peter

    Screening mammography is the current standard in detecting breast cancer. However, its fundamental disadvantage is that it projects a 3D object into a 2D image. Small lesions are difficult to detect when superimposed over layers of normal tissue. Commercial Computed Tomography (CT) produces a true 3D image yet has a limited role in mammography due to relatively low resolution and contrast. With the intent of enhancing mammography and breast CT, we have developed an algorithm which can produce 3D electron density images using a single projection. Imaging an object with x rays produces a characteristic scattered photon spectrum at the detector plane. A known incident beam spectrum, beam shape, and arbitrary 3D matrix of electron density values enable a theoretical scattered photon distribution to be calculated. An iterative minimization algorithm is used to make changes to the electron density voxel matrix to reduce regular differences between the theoretical and the experimentally measured distributions. The object is characterized by the converged electron density image. This technique has been validated in simulation using data produced by the EGSnrc Monte Carlo code system. At both mammographic and CT energies, a scanning polychromatic pencil beam was used to image breast tissue phantoms containing lesion-like inhomogeneities. The resulting Monte Carlo data is processed using a Nelder-Mead iterative algorithm (MATLAB) to produce the 3D matrix of electron density values. Resulting images have confirmed the ability of the algorithm to detect various 1x1x2.5 mm3 lesions with calcification content as low as 0.5% (p<0.005) at a dose comparable to mammography.

  20. Three-dimensional analysis of alveolar bone resorption by image processing of 3-D dental CT images

    NASA Astrophysics Data System (ADS)

    Nagao, Jiro; Kitasaka, Takayuki; Mori, Kensaku; Suenaga, Yasuhito; Yamada, Shohzoh; Naitoh, Munetaka

    2006-03-01

    We have developed a novel system that provides total support for assessment of alveolar bone resorption, caused by periodontitis, based on three-dimensional (3-D) dental CT images. In spite of the difficulty in perceiving the complex 3-D shape of resorption, dentists assessing resorption location and severity have been relying on two-dimensional radiography and probing, which merely provides one-dimensional information (depth) about resorption shape. However, there has been little work on assisting assessment of the disease by 3-D image processing and visualization techniques. This work provides quantitative evaluation results and figures for our system that measures the three-dimensional shape and spread of resorption. It has the following functions: (1) measures the depth of resorption by virtually simulating probing in the 3-D CT images, taking advantage of image processing of not suffering obstruction by teeth on the inter-proximal sides and much smaller measurement intervals than the conventional examination; (2) visualizes the disposition of the depth by movies and graphs; (3) produces a quantitative index and intuitive visual representation of the spread of resorption in the inter-radicular region in terms of area; and (4) calculates the volume of resorption as another severity index in the inter-radicular region and the region outside it. Experimental results in two cases of 3-D dental CT images and a comparison of the results with the clinical examination results and experts' measurements of the corresponding patients confirmed that the proposed system gives satisfying results, including 0.1 to 0.6mm of resorption measurement (probing) error and fairly intuitive presentation of measurement and calculation results.

  1. Thoracic Temporal Subtraction Three Dimensional Computed Tomography (3D-CT): Screening for Vertebral Metastases of Primary Lung Cancers

    PubMed Central

    Iwano, Shingo; Ito, Rintaro; Umakoshi, Hiroyasu; Karino, Takatoshi; Inoue, Tsutomu; Li, Yuanzhong; Naganawa, Shinji

    2017-01-01

    Purpose We developed an original, computer-aided diagnosis (CAD) software that subtracts the initial thoracic vertebral three-dimensional computed tomography (3D-CT) image from the follow-up 3D-CT image. The aim of this study was to investigate the efficacy of this CAD software during screening for vertebral metastases on follow-up CT images of primary lung cancer patients. Materials and Methods The interpretation experiment included 30 sets of follow-up CT scans in primary lung cancer patients and was performed by two readers (readers A and B), who each had 2.5 years’ experience reading CT images. In 395 vertebrae from C6 to L3, 46 vertebral metastases were identified as follows: osteolytic metastases (n = 17), osteoblastic metastases (n = 14), combined osteolytic and osteoblastic metastases (n = 6), and pathological fractures (n = 9). Thirty-six lesions were in the anterior component (vertebral body), and 10 lesions were in the posterior component (vertebral arch, transverse process, and spinous process). The area under the curve (AUC) by receiver operating characteristic (ROC) curve analysis and the sensitivity and specificity for detecting vertebral metastases were compared with and without CAD for each observer. Results Reader A detected 47 abnormalities on CT images without CAD, and 33 of them were true-positive metastatic lesions. Using CAD, reader A detected 57 abnormalities, and 38 were true positives. The sensitivity increased from 0.717 to 0.826, and on ROC curve analysis, AUC with CAD was significantly higher than that without CAD (0.849 vs. 0.902, p = 0.021). Reader B detected 40 abnormalities on CT images without CAD, and 36 of them were true-positive metastatic lesions. Using CAD, reader B detected 44 abnormalities, and 39 were true positives. The sensitivity increased from 0.783 to 0.848, and AUC with CAD was nonsignificantly higher than that without CAD (0.889 vs. 0.910, p = 0.341). Both readers detected more osteolytic and osteoblastic

  2. An innovative strategy for the identification and 3D reconstruction of pancreatic cancer from CT images.

    PubMed

    Marconi, S; Pugliese, L; Del Chiaro, M; Pozzi Mucelli, R; Auricchio, F; Pietrabissa, A

    2016-09-01

    We propose an innovative tool for Pancreatic Ductal AdenoCarcinoma 3D reconstruction from Multi-Detector-Computed Tomography. The tumor mass is discriminated from health tissue, and the resulting segmentation labels are rendered preserving information on different hypodensity levels. The final 3D virtual model includes also pancreas and main peri-pancreatic vessels, and it is suitable for 3D printing. We performed a preliminary evaluation of the tool effectiveness presenting ten cases of Pancreatic Ductal AdenoCarcinoma processed with the tool to an expert radiologist who can correct the result of the discrimination. In seven of ten cases, the 3D reconstruction is accepted without any modification, while in three cases, only 1.88, 5.13, and 5.70 %, respectively, of the segmentation labels are modified, preliminary proving the high effectiveness of the tool.

  3. Algorithm of pulmonary emphysema extraction using thoracic 3-D CT images

    NASA Astrophysics Data System (ADS)

    Saita, Shinsuke; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Ohmatsu, Hironobu; Tominaga, Keigo; Eguchi, Kenji; Moriyama, Noriyuki

    2008-03-01

    Emphysema patients have the tendency to increase due to aging and smoking. Emphysematous disease destroys alveolus and to repair is impossible, thus early detection is essential. CT value of lung tissue decreases due to the destruction of lung structure. This CT value becomes lower than the normal lung- low density absorption region or referred to as Low Attenuation Area (LAA). So far, the conventional way of extracting LAA by simple thresholding has been proposed. However, the CT value of CT image fluctuates due to the measurement conditions, with various bias components such as inspiration, expiration and congestion. It is therefore necessary to consider these bias components in the extraction of LAA. We removed these bias components and we proposed LAA extraction algorithm. This algorithm has been applied to the phantom image. Then, by using the low dose CT(normal: 30 cases, obstructive lung disease: 26 cases), we extracted early stage LAA and quantitatively analyzed lung lobes using lung structure.

  4. Sparse representation-based volumetric super-resolution algorithm for 3D CT images of reservoir rocks

    NASA Astrophysics Data System (ADS)

    Li, Zhengji; Teng, Qizhi; He, Xiaohai; Yue, Guihua; Wang, Zhengyong

    2017-09-01

    The parameter evaluation of reservoir rocks can help us to identify components and calculate the permeability and other parameters, and it plays an important role in the petroleum industry. Until now, computed tomography (CT) has remained an irreplaceable way to acquire the microstructure of reservoir rocks. During the evaluation and analysis, large samples and high-resolution images are required in order to obtain accurate results. Owing to the inherent limitations of CT, however, a large field of view results in low-resolution images, and high-resolution images entail a smaller field of view. Our method is a promising solution to these data collection limitations. In this study, a framework for sparse representation-based 3D volumetric super-resolution is proposed to enhance the resolution of 3D voxel images of reservoirs scanned with CT. A single reservoir structure and its downgraded model are divided into a large number of 3D cubes of voxel pairs and these cube pairs are used to calculate two overcomplete dictionaries and the sparse-representation coefficients in order to estimate the high frequency component. Future more, to better result, a new feature extract method with combine BM4D together with Laplacian filter are introduced. In addition, we conducted a visual evaluation of the method, and used the PSNR and FSIM to evaluate it qualitatively.

  5. Breast volume estimation from systematic series of CT scans using the Cavalieri principle and 3D reconstruction.

    PubMed

    Erić, Mirela; Anderla, Andraš; Stefanović, Darko; Drapšin, Miodrag

    2014-01-01

    Preoperative breast volume estimation is very important for the success of the breast surgery. In the present study, two different breast volume determination methods, Cavalieri principle and 3D reconstruction were compared. Consecutive sections were taken in slice thickness of 5 mm. Every 2nd breast section in a set of consecutive sections was selected. We marked breast tissue with blue line on each selected section, and so prepared CT scans used for breast volume estimation. The volumes of the 60 breasts were estimated using the Cavalieri principle and 3D reconstruction. The mean breast volume value was established to be 467.79 ± 188.90 cm(3) with Cavalieri method and 465.91 ± 191.41 cm(3) with 3D reconstruction. The mean CE for the estimates in this study was calculated as 0.25%. Skin-sparing volume was about 91.64% of the whole breast volume. Both methods are very accurate and have a strong linear association. Our results suggest that the calculation of breast volume or its part in vivo from systematic series of CT scans using the Cavalieri principle or 3D breast reconstruction is accurate enough to have a significant clinical benefit in planning reconstructive breast surgery. These methods can help the surgeon guide the choice of the most appropriate implant or/and flap preoperatively. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  6. Simultaneous screening for osteoporosis at CT colonography: bone mineral density assessment using MDCT attenuation techniques compared with the DXA reference standard.

    PubMed

    Pickhardt, Perry J; Lee, Lawrence J; del Rio, Alejandro Muñoz; Lauder, Travis; Bruce, Richard J; Summers, Ron M; Pooler, B Dustin; Binkley, Neil

    2011-09-01

    The purpose of this study was to evaluate the utility of lumbar spine attenuation measurement for bone mineral density (BMD) assessment at screening computed tomographic colonography (CTC) using central dual-energy X-ray absorptiometry (DXA) as the reference standard. Two-hundred and fifty-two adults (240 women and 12 men; mean age 58.9 years) underwent CTC screening and central DXA BMD measurement within 2 months (mean interval 25.0 days). The lowest DXA T-score between the spine and hip served as the reference standard, with low BMD defined per World Health Organization as osteoporosis (DXA T-score ≤ -2.5) or osteopenia (DXA T-score between -1.0 and -2.4). Both phantomless quantitative computed tomography (QCT) and simple nonangled region-of-interest (ROI) multi-detector CT (MDCT) attenuation measurements were applied to the T(12) -L(5) levels. The ability to predict osteoporosis and low BMD (osteoporosis or osteopenia) by DXA was assessed. A BMD cut-off of 90 mg/mL at phantomless QCT yielded 100% sensitivity for osteoporosis (29 of 29) and a specificity of 63.8% (143 of 224); 87.2% (96 of 110) below this threshold had low BMD and 49.6% (69 of 139) above this threshold had normal BMD at DXA. At L(1) , a trabecular ROI attenuation cut-off of 160 HU was 100% sensitive for osteoporosis (29 of 29), with a specificity of 46.4% (104 of 224); 83.9% (125 of 149) below this threshold had low BMD and 57.5% (59/103) above had normal BMD at DXA. ROI performance was similar at all individual T(12) -L(5) levels. At ROC analysis, AUC for osteoporosis was 0.888 for phantomless QCT [95% confidence interval (CI) 0.780-0.946] and ranged from 0.825 to 0.853 using trabecular ROIs at single lumbar levels (0.864; 95% CI 0.752-0.930 at multivariate analysis). Supine-prone reproducibility was better with the simple ROI method compared with QCT. It is concluded that both phantomless QCT and simple ROI attenuation measurements of the lumbar spine are effective for BMD screening at CTC

  7. Reduced and Full-Preparation CT Colonography, Fecal Immunochemical Test, and Colonoscopy for Population Screening of Colorectal Cancer: A Randomized Trial.

    PubMed

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

    2016-02-01

    Population screening for colorectal cancer (CRC) is widely adopted, but the preferred strategy is still under debate. We aimed to compare reduced (r-CTC) and full cathartic preparation CT colonography (f-CTC), fecal immunochemical test (FIT), and optical colonoscopy (OC) as primary screening tests for CRC. Citizens of a district of Florence, Italy, age 54 to 65 years, were allocated (8:2.5:2.5:1) with simple randomization to be invited by mail to one of four screening interventions: 1) biennial FIT for three rounds, 2) r-CTC, 3) f-CTC, 4) OC. Patients tested positive to FIT or CTC (at least one polyp ≥6mm) were referred to OC work-up. The primary outcomes were participation rate and detection rate (DR) for cancer or advanced adenoma (advanced neoplasia). All statistical tests were two-sided. Sixteen thousand eighty-seven randomly assigned subjects were invited to the assigned screening test. Participation rates were 50.4% (4677/9288) for first-round FIT, 28.1% (674/2395) for r-CTC, 25.2% (612/2430) for f-CTC, and 14.8% (153/1036) for OC. All differences between groups were statistically significant (P = .047 for r-CTC vs f-CTC; P < .001 for all others). DRs for advanced neoplasia were 1.7% (79/4677) for first-round FIT, 5.5% (37/674) for r-CTC, 4.9% (30/612) for f-CTC, and 7.2% (11/153) for OC. Differences in DR between CTC groups and FIT were statistically significant (P < .001), but not between r-CTC and f-CTC (P = .65). Reduced preparation increases participation in CTC. Lower attendance and higher DR of CTC as compared with FIT are key factors for the optimization of its role in population screening of CRC. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Cervical vertebrae maturation index estimates on cone beam CT: 3D reconstructions vs sagittal sections

    PubMed Central

    Bonfim, Marco A E; Costa, André L F; Ximenez, Michel E L; Cotrim-Ferreira, Flávio A; Ferreira-Santos, Rívea I

    2016-01-01

    Objectives: The aim of this study was to evaluate the performance of CBCT three-dimensional (3D) reconstructions and sagittal sections for estimates of cervical vertebrae maturation index (CVMI). Methods: The sample consisted of 72 CBCT examinations from patients aged 8–16 years (45 females and 27 males) selected from the archives of two private clinics. Two calibrated observers (kappa scores: ≥0.901) interpreted the CBCT settings twice. Intra- and interobserver agreement for both imaging exhibition modes was analyzed by kappa statistics, which was also used to analyze the agreement between 3D reconstructions and sagittal sections. Correlations between cervical vertebrae maturation estimates and chronological age, as well as between the assessments by 3D reconstructions and sagittal sections, were analyzed using gamma Goodman–Kruskal coefficients (α = 0.05). Results: The kappa scores evidenced almost perfect agreement between the first and second assessments of the cervical vertebrae by 3D reconstructions (0.933–0.983) and sagittal sections (0.983–1.000). Similarly, the agreement between 3D reconstructions and sagittal sections was almost perfect (kappa index: 0.983). In most divergent cases, the difference between 3D reconstructions and sagittal sections was one stage of CVMI. Strongly positive correlations (>0.8, p < 0.001) were found not only between chronological age and CVMI but also between the estimates by 3D reconstructions and sagittal sections (p < 0.001). Conclusions: Although CBCT imaging must not be used exclusively for this purpose, it may be suitable for skeletal maturity assessments. PMID:26509559

  9. Towards real-time 3D US to CT bone image registration using phase and curvature feature based GMM matching.

    PubMed

    Brounstein, Anna; Hacihaliloglu, Ilker; Guy, Pierre; Hodgson, Antony; Abugharbieh, Rafeef

    2011-01-01

    In order to use pre-operatively acquired computed tomography (CT) scans to guide surgical tool movements in orthopaedic surgery, the CT scan must first be registered to the patient's anatomy. Three-dimensional (3D) ultrasound (US) could potentially be used for this purpose if the registration process could be made sufficiently automatic, fast and accurate, but existing methods have difficulties meeting one or more of these criteria. We propose a near-real-time US-to-CT registration method that matches point clouds extracted from local phase images with points selected in part on the basis of local curvature. The point clouds are represented as Gaussian Mixture Models (GMM) and registration is achieved by minimizing the statistical dissimilarity between the GMMs using an L2 distance metric. We present quantitative and qualitative results on both phantom and clinical pelvis data and show a mean registration time of 2.11 s with a mean accuracy of 0.49 mm.

  10. Dosimetric impact of different CT datasets for stereotactic treatment planning using 3D conformal radiotherapy or volumetric modulated arc therapy.

    PubMed

    Oechsner, Markus; Odersky, Leonhard; Berndt, Johannes; Combs, Stephanie Elisabeth; Wilkens, Jan Jakob; Duma, Marciana Nona

    2015-12-01

    The purpose of this study was to assess the impact on dose to the planning target volume (PTV) and organs at risk (OAR) by using four differently generated CT datasets for dose calculation in stereotactic body radiotherapy (SBRT) of lung and liver tumors. Additionally, dose differences between 3D conformal radiotherapy and volumetric modulated arc therapy (VMAT) plans calculated on these CT datasets were determined. Twenty SBRT patients, ten lung cases and ten liver cases, were retrospectively selected for this study. Treatment plans were optimized on average intensity projection (AIP) CTs using 3D conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT). Afterwards, the plans were copied to the planning CTs (PCT), maximum intensity projection (MIP) and mid-ventilation (MidV) CT datasets and dose was recalculated keeping all beam parameters and monitor units unchanged. Ipsilateral lung and liver volumes and dosimetric parameters for PTV (Dmean, D2, D98, D95), ipsilateral lung and liver (Dmean, V30, V20, V10) were determined and statistically analysed using Wilcoxon test. Significant but small mean differences were found for PTV dose between the CTs (lung SBRT: ≤2.5 %; liver SBRT: ≤1.6 %). MIPs achieved the smallest lung and the largest liver volumes. OAR mean doses in MIP plans were distinctly smaller than in the other CT datasets. Furthermore, overlapping of tumors with the diaphragm results in underestimated ipsilateral lung dose in MIP plans. Best agreement was found between AIP and MidV (lung SBRT). Overall, differences in liver SBRT were smaller than in lung SBRT and VMAT plans achieved slightly smaller differences than 3D-CRT plans. Only small differences were found for PTV parameters between the four CT datasets. Larger differences occurred for the doses to organs at risk (ipsilateral lung, liver) especially for MIP plans. No relevant differences were observed between 3D-CRT or VMAT plans. MIP CTs are not appropriate for OAR dose

  11. Noise reduction for low-dose helical CT by 3D penalized weighted least-squares sinogram smoothing

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Li, Tianfang; Lu, Hongbing; Liang, Zhengrong

    2006-03-01

    Helical computed tomography (HCT) has several advantages over conventional step-and-shoot CT for imaging a relatively large object, especially for dynamic studies. However, HCT may increase X-ray exposure significantly to the patient. This work aims to reduce the radiation by lowering the X-ray tube current (mA) and filtering the low-mA (or dose) sinogram noise. Based on the noise properties of HCT sinogram, a three-dimensional (3D) penalized weighted least-squares (PWLS) objective function was constructed and an optimal sinogram was estimated by minimizing the objective function. To consider the difference of signal correlation among different direction of the HCT sinogram, an anisotropic Markov random filed (MRF) Gibbs function was designed as the penalty. The minimization of the objection function was performed by iterative Gauss-Seidel updating strategy. The effectiveness of the 3D-PWLS sinogram smoothing for low-dose HCT was demonstrated by a 3D Shepp-Logan head phantom study. Comparison studies with our previously developed KL domain PWLS sinogram smoothing algorithm indicate that the KL+2D-PWLS algorithm shows better performance on in-plane noise-resolution trade-off while the 3D-PLWS shows better performance on z-axis noise-resolution trade-off. Receiver operating characteristic (ROC) studies by using channelized Hotelling observer (CHO) shows that 3D-PWLS and KL+2DPWLS algorithms have similar performance on detectability in low-contrast environment.

  12. Piecewise-diffeomorphic image registration: application to the motion estimation between 3D CT lung images with sliding conditions.

    PubMed

    Risser, Laurent; Vialard, François-Xavier; Baluwala, Habib Y; Schnabel, Julia A

    2013-02-01

    In this paper, we propose a new strategy for modelling sliding conditions when registering 3D images in a piecewise-diffeomorphic framework. More specifically, our main contribution is the development of a mathematical formalism to perform Large Deformation Diffeomorphic Metric Mapping registration with sliding conditions. We also show how to adapt this formalism to the LogDemons diffeomorphic registration framework. We finally show how to apply this strategy to estimate the respiratory motion between 3D CT pulmonary images. Quantitative tests are performed on 2D and 3D synthetic images, as well as on real 3D lung images from the MICCAI EMPIRE10 challenge. Results show that our strategy estimates accurate mappings of entire 3D thoracic image volumes that exhibit a sliding motion, as opposed to conventional registration methods which are not capable of capturing discontinuous deformations at the thoracic cage boundary. They also show that although the deformations are not smooth across the location of sliding conditions, they are almost always invertible in the whole image domain. This would be helpful for radiotherapy planning and delivery. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  13. Efficient 3D texture feature extraction from CT images for computer-aided diagnosis of pulmonary nodules

    NASA Astrophysics Data System (ADS)

    Han, Fangfang; Wang, Huafeng; Song, Bowen; Zhang, Guopeng; Lu, Hongbing; Moore, William; Liang, Zhengrong; Zhao, Hong

    2014-03-01

    Texture feature from chest CT images for malignancy assessment of pulmonary nodules has become an un-ignored and efficient factor in Computer-Aided Diagnosis (CADx). In this paper, we focus on extracting as fewer as needed efficient texture features, which can be combined with other classical features (e.g. size, shape, growing rate, etc.) for assisting lung nodule diagnosis. Based on a typical calculation algorithm of texture features, namely Haralick features achieved from the gray-tone spatial-dependence matrices, we calculated two dimensional (2D) and three dimensional (3D) Haralick features from the CT images of 905 nodules. All of the CT images were downloaded from the Lung Image Database Consortium and Image Database Resource Initiative (LIDC-IDRI), which is the largest public chest database. 3D Haralick feature model of thirteen directions contains more information from the relationships on the neighbor voxels of different slices than 2D features from only four directions. After comparing the efficiencies of 2D and 3D Haralick features applied on the diagnosis of nodules, principal component analysis (PCA) algorithm was used to extract as fewer as needed efficient texture features. To achieve an objective assessment of the texture features, the support vector machine classifier was trained and tested repeatedly for one hundred times. And the statistical results of the classification experiments were described by an average receiver operating characteristic (ROC) curve. The mean value (0.8776) of the area under the ROC curves in our experiments can show that the two extracted 3D Haralick projected features have the potential to assist the classification of benign and malignant nodules.

  14. [Accurate 3D free-form registration between fan-beam CT and cone-beam CT].

    PubMed

    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.

  15. Influence of the Alveolar Cleft Type on Preoperative Estimation Using 3D CT Assessment for Alveolar Cleft

    PubMed Central

    Choi, Hang Suk; Choi, Hyun Gon; Kim, Soon Heum; Park, Hyung Jun; Shin, Dong Hyeok; Jo, Dong In; Kim, Cheol Keun

    2012-01-01

    Background The bone graft for the alveolar cleft has been accepted as one of the essential treatments for cleft lip patients. Precise preoperative measurement of the architecture and size of the bone defect in alveolar cleft has been considered helpful for increasing the success rate of bone grafting because those features may vary with the cleft type. Recently, some studies have reported on the usefulness of three-dimensional (3D) computed tomography (CT) assessment of alveolar bone defect; however, no study on the possible implication of the cleft type on the difference between the presumed and actual value has been conducted yet. We aimed to evaluate the clinical predictability of such measurement using 3D CT assessment according to the cleft type. Methods The study consisted of 47 pediatric patients. The subjects were divided according to the cleft type. CT was performed before the graft operation and assessed using image analysis software. The statistical significance of the difference between the preoperative estimation and intraoperative measurement was analyzed. Results The difference between the preoperative and intraoperative values were -0.1±0.3 cm3 (P=0.084). There was no significant intergroup difference, but the groups with a cleft palate showed a significant difference of -0.2±0.3 cm3 (P<0.05). Conclusions Assessment of the alveolar cleft volume using 3D CT scan data and image analysis software can help in selecting the optimal graft procedure and extracting the correct volume of cancellous bone for grafting. Considering the cleft type, it would be helpful to extract an additional volume of 0.2 cm3 in the presence of a cleft palate. PMID:23094242

  16. Local plate/rod descriptors of 3D trabecular bone micro-CT images from medial axis topologic analysis

    SciTech Connect

    Peyrin, Francoise; Attali, Dominique; Chappard, Christine; Benhamou, Claude Laurent

    2010-08-15

    Purpose: Trabecular bone microarchitecture is made of a complex network of plate and rod structures evolving with age and disease. The purpose of this article is to propose a new 3D local analysis method for the quantitative assessment of parameters related to the geometry of trabecular bone microarchitecture. Methods: The method is based on the topologic classification of the medial axis of the 3D image into branches, rods, and plates. Thanks to the reversibility of the medial axis, the classification is next extended to the whole 3D image. Finally, the percentages of rods and plates as well as their mean thicknesses are calculated. The method was applied both to simulated test images and 3D micro-CT images of human trabecular bone. Results: The classification of simulated phantoms made of plates and rods shows that the maximum error in the quantitative percentages of plate and rods is less than 6% and smaller than with the structure model index (SMI). Micro-CT images of human femoral bone taken in osteoporosis and early or advanced osteoarthritis were analyzed. Despite the large physiological variability, the present method avoids the underestimation of rods observed with other local methods. The relative percentages of rods and plates were not significantly different between osteoarthritis and osteoporotic groups, whereas their absolute percentages were in relation to an increase of rod and plate thicknesses in advanced osteoarthritis with also higher relative and absolute number of nodes. Conclusions: The proposed method is model-independent, robust to surface irregularities, and enables geometrical characterization of not only skeletal structures but entire 3D images. Its application provided more accurate results than the standard SMI on simple simulated phantoms, but the discrepancy observed on the advanced osteoarthritis group raises questions that will require further investigations. The systematic use of such a local method in the characterization of

  17. Computer-aided diagnosis of pulmonary nodules on CT scans: segmentation and classification using 3D active contours.

    PubMed

    Way, Ted W; Hadjiiski, Lubomir M; Sahiner, Berkman; Chan, Heang-Ping; Cascade, Philip N; Kazerooni, Ella A; Bogot, Naama; Zhou, Chuan

    2006-07-01

    We are developing a computer-aided diagnosis (CAD) system to classify malignant and benign lung nodules found on CT scans. A fully automated system was designed to segment the nodule from its surrounding structured background in a local volume of interest (VOI) and to extract image features for classification. Image segmentation was performed with a three-dimensional (3D) active contour (AC) method. A data set of 96 lung nodules (44 malignant, 52 benign) from 58 patients was used in this study. The 3D AC model is based on two-dimensional AC with the addition of three new energy components to take advantage of 3D information: (1) 3D gradient, which guides the active contour to seek the object surface, (2) 3D curvature, which imposes a smoothness constraint in the z direction, and (3) mask energy, which penalizes contours that grow beyond the pleura or thoracic wall. The search for the best energy weights in the 3D AC model was guided by a simplex optimization method. Morphological and gray-level features were extracted from the segmented nodule. The rubber band straightening transform (RBST) was applied to the shell of voxels surrounding the nodule. Texture features based on run-length statistics were extracted from the RBST image. A linear discriminant analysis classifier with stepwise feature selection was designed using a second simplex optimization to select the most effective features. Leave-one-case-out resampling was used to train and test the CAD system. The system achieved a test area under the receiver operating characteristic curve (A(z)) of 0.83 +/- 0.04. Our preliminary results indicate that use of the 3D AC model and the 3D texture features surrounding the nodule is a promising approach to the segmentation and classification of lung nodules with CAD. The segmentation performance of the 3D AC model trained with our data set was evaluated with 23 nodules available in the Lung Image Database Consortium (LIDC). The lung nodule volumes segmented by the 3D

  18. Computer-aided diagnosis of pulmonary nodules on CT scans: Segmentation and classification using 3D active contours

    PubMed Central

    Way, Ted W.; Hadjiiski, Lubomir M.; Sahiner, Berkman; Chan, Heang-Ping; Cascade, Philip N.; Kazerooni, Ella A.; Bogot, Naama; Zhou, Chuan

    2009-01-01

    We are developing a computer-aided diagnosis (CAD) system to classify malignant and benign lung nodules found on CT scans. A fully automated system was designed to segment the nodule from its surrounding structured background in a local volume of interest (VOI) and to extract image features for classification. Image segmentation was performed with a three-dimensional (3D) active contour (AC) method. A data set of 96 lung nodules (44 malignant, 52 benign) from 58 patients was used in this study. The 3D AC model is based on two-dimensional AC with the addition of three new energy components to take advantage of 3D information: (1) 3D gradient, which guides the active contour to seek the object surface, (2) 3D curvature, which imposes a smoothness constraint in the z direction, and (3) mask energy, which penalizes contours that grow beyond the pleura or thoracic wall. The search for the best energy weights in the 3D AC model was guided by a simplex optimization method. Morphological and gray-level features were extracted from the segmented nodule. The rubber band straightening transform (RBST) was applied to the shell of voxels surrounding the nodule. Texture features based on run-length statistics were extracted from the RBST image. A linear discriminant analysis classifier with stepwise feature selection was designed using a second simplex optimization to select the most effective features. Leave-one-case-out resampling was used to train and test the CAD system. The system achieved a test area under the receiver operating characteristic curve (Az) of 0.83±0.04. Our preliminary results indicate that use of the 3D AC model and the 3D texture features surrounding the nodule is a promising approach to the segmentation and classification of lung nodules with CAD. The segmentation performance of the 3D AC model trained with our data set was evaluated with 23 nodules available in the Lung Image Database Consortium (LIDC). The lung nodule volumes segmented by the 3D AC

  19. The effect of CT dose on glenohumeral joint congruency measurements using 3D reconstructed patient-specific bone models

    NASA Astrophysics Data System (ADS)

    Lalone, Emily A.; Fox, Anne-Marie V.; Kedgley, Angela E.; Jenkyn, Thomas R.; King, Graham J. W.; Athwal, George S.; Johnson, James A.; Peters, Terry M.

    2011-10-01

    The study of joint congruency at the glenohumeral joint of the shoulder using computed tomography (CT) and three-dimensional (3D) reconstructions of joint surfaces is an area of significant clinical interest. However, ionizing radiation delivered to patients during CT examinations is much higher than other types of radiological imaging. The shoulder represents a significant challenge for this modality as it is adjacent to the thyroid gland and breast tissue. The objective of this study was to determine the optimal CT scanning techniques that would minimize radiation dose while accurately quantifying joint congruency of the shoulder. The results suggest that only one-tenth of the standard applied total current (mA) and a pitch ratio of 1.375:1 was necessary to produce joint congruency values consistent with that of the higher dose scans. Using the CT scanning techniques examined in this study, the effective dose applied to the shoulder to quantify joint congruency was reduced by 88.9% compared to standard clinical CT imaging techniques.

  20. Numerical investigation of 3-D constraint effects on brittle fracture in SE(B) and C(T) specimens

    SciTech Connect

    Nevalainen, M.; Dodds, R.H. Jr.

    1996-07-01

    This investigation employs 3-D nonlinear finite element analyses to conduct an extensive parametric evaluation of crack front stress triaxiality for deep notch SE(B) and C(T) specimens and shallow notch SE(B) specimens, with and without side grooves. Crack front conditions are characterized in terms of J-Q trajectories and the constraint scaling model for cleavage fracture toughness proposed previously by Dodds and Anderson. The 3-D computational results imply that a significantly less strict size/deformation limit, relative to the limits indicated by previous plane-strain computations, is needed to maintain small-scale yielding conditions at fracture by a stress- controlled, cleavage mechanism in deep notch SE(B) and C(T) specimens. Additional new results made available from the 3-D analyses also include revised {eta}-plastic factors for use in experimental studies to convert measured work quantities to thickness average and maximum (local) J-values over the crack front.

  1. A visual data-mining approach using 3D thoracic CT images for classification between benign and malignant pulmonary nodules

    NASA Astrophysics Data System (ADS)

    Kawata, Yoshiki; Niki, Noboru; Ohamatsu, Hironobu; Kusumoto, Masahiko; Kakinuma, Ryutaro; Mori, Kiyoshi; Yamada, K.; Nishiyama, Hiroyuki; Eguchi, Kenji; Kaneko, Masahiro; Moriyama, Noriyuki

    2003-05-01

    This paper presents a visual data-mining approach to assist physicians for classification between benign and malignant pulmonary nodules. This approach retrieves and displays nodules which exhibit morphological and internal profiles consistent to the nodule in question. It uses a three-dimensional (3-D) CT image database of pulmonary nodules for which diagnosis is known. The central module in this approach makes possible analysis of the query nodule image and extraction of the features of interest: shape, surrounding structure, and internal structure of the nodules. The nodule shape is characterized by principal axes, while the surrounding and internal structure is represented by the distribution pattern of CT density and 3-D curvature indexes. The nodule representation is then applied to a similarity measure such as a correlation coefficient. For each query case, we sort all the nodules of the database from most to less similar ones. By applying the retrieval method to our database, we present its feasibility to search the similar 3-D nodule images.

  2. Mesenteric Vasculature-guided Small Bowel Segmentation on 3D CT

    PubMed Central

    Zhang, Weidong; Liu, Jiamin; Yao, Jianhua; Louie, Adeline; Nguyen, Tan B.; Wank, Stephen; Nowinski, Wieslaw L.; Summers, Ronald M.

    2014-01-01

    Due to its importance and possible applications in visualization, tumor detection and pre-operative planning, automatic small bowel segmentation is essential for computer-aided diagnosis of small bowel pathology. However, segmenting the small bowel directly on CT scans is very difficult because of the low image contrast on CT scans and high tortuosity of the small bowel and its close proximity to other abdominal organs. Motivated by the intensity characteristics of abdominal CT images, the anatomic relationship between the mesenteric vasculature and the small bowel, and potential usefulness of the mesenteric vasculature for establishing the path of the small bowel, we propose a novel mesenteric vasculature map-guided method for small bowel segmentation on high-resolution CT angiography scans. The major mesenteric arteries are first segmented using a vessel tracing method based on multi-linear subspace vessel model and Bayesian inference. Second, multi-view, multi-scale vesselness enhancement filters are used to segment small vessels, and vessels directly or indirectly connecting to the superior mesenteric artery are classified as mesenteric vessels. Third, a mesenteric vasculature map is built by linking vessel bifurcation points, and the small bowel is segmented by employing the mesenteric vessel map and fuzzy connectness. The method was evaluated on 11 abdominal CT scans of patients suspected of having carcinoid tumors with manually labeled reference standard. The result, 82.5% volume overlap accuracy compared with the reference standard, shows it is feasible to segment the small bowel on CT scans using the mesenteric vasculature as a roadmap. PMID:23807437

  3. Quantitative 3D Ultrashort Time-to-Echo (UTE) MRI and Micro-CTCT) Evaluation of the Temporomandibular Joint (TMJ) Condylar Morphology

    PubMed Central

    Geiger, Daniel; Bae, Won C.; Statum, Sheronda; Du, Jiang; Chung, Christine B.

    2014-01-01

    Objective Temporomandibular dysfunction involves osteoarthritis of the TMJ, including degeneration and morphologic changes of the mandibular condyle. Purpose of this study was to determine accuracy of novel 3D-UTE MRI versus micro-CTCT) for quantitative evaluation of mandibular condyle morphology. Material & Methods Nine TMJ condyle specimens were harvested from cadavers (2M, 3F; Age 85 ± 10 yrs., mean±SD). 3D-UTE MRI (TR=50ms, TE=0.05 ms, 104 μm isotropic-voxel) was performed using a 3-T MR scanner and μCT (18 μm isotropic-voxel) was performed. MR datasets were spatially-registered with μCT dataset. Two observers segmented bony contours of the condyles. Fibrocartilage was segmented on MR dataset. Using a custom program, bone and fibrocartilage surface coordinates, Gaussian curvature, volume of segmented regions and fibrocartilage thickness were determined for quantitative evaluation of joint morphology. Agreement between techniques (MRI vs. μCT) and observers (MRI vs. MRI) for Gaussian curvature, mean curvature and segmented volume of the bone were determined using intraclass correlation correlation (ICC) analyses. Results Between MRI and μCT, the average deviation of surface coordinates was 0.19±0.15 mm, slightly higher than spatial resolution of MRI. Average deviation of the Gaussian curvature and volume of segmented regions, from MRI to μCT, was 5.7±6.5% and 6.6±6.2%, respectively. ICC coefficients (MRI vs. μCT) for Gaussian curvature, mean curvature and segmented volumes were respectively 0.892, 0.893 and 0.972. Between observers (MRI vs. MRI), the ICC coefficients were 0.998, 0.999 and 0.997 respectively. Fibrocartilage thickness was 0.55±0.11 mm, as previously described in literature for grossly normal TMJ samples. Conclusion 3D-UTE MR quantitative evaluation of TMJ condyle morphology ex-vivo, including surface, curvature and segmented volume, shows high correlation against μCT and between observers. In addition, UTE MRI allows

  4. Extraction of 3D Femur Neck Trabecular Bone Architecture from Clinical CT Images in Osteoporotic Evaluation: a Novel Framework.

    PubMed

    Sapthagirivasan, V; Anburajan, M; Janarthanam, S

    2015-08-01

    The early detection of osteoporosis risk enhances the lifespan and quality of life of an individual. A reasonable in-vivo assessment of trabecular bone strength at the proximal femur helps to evaluate the fracture risk and henceforth, to understand the associated structural dynamics on occurrence of osteoporosis. The main aim of our study was to develop a framework to automatically determine the trabecular bone strength from clinical femur CT images and thereby to estimate its correlation with BMD. All the 50 studied south Indian female subjects aged 30 to 80 years underwent CT and DXA measurements at right femur region. Initially, the original CT slices were intensified and active contour model was utilised for the extraction of the neck region. After processing through a novel process called trabecular enrichment approach (TEA), the three dimensional (3D) trabecular features were extracted. The extracted 3D trabecular features, such as volume fraction (VF), solidity of delta points (SDP) and boundness, demonstrated a significant correlation with femoral neck bone mineral density (r = 0.551, r = 0.432, r = 0.552 respectively) at p < 0.001. The higher area under the curve values of the extracted features (VF: 85.3 %; 95CI: 68.2-100 %, SDP: 82.1 %; 95CI: 65.1-98.9 % and boundness: 90.4 %; 95CI: 78.7-100 %) were observed. The findings suggest that the proposed framework with TEA method would be useful for spotting women vulnerable to osteoporotic risk.

  5. Geometry-based vs. intensity-based medical image registration: A comparative study on 3D CT data.

    PubMed

    Savva, Antonis D; Economopoulos, Theodore L; Matsopoulos, George K

    2016-02-01

    Spatial alignment of Computed Tomography (CT) data sets is often required in numerous medical applications and it is usually achieved by applying conventional exhaustive registration techniques, which are mainly based on the intensity of the subject data sets. Those techniques consider the full range of data points composing the data, thus negatively affecting the required processing time. Alternatively, alignment can be performed using the correspondence of extracted data points from both sets. Moreover, various geometrical characteristics of those data points can be used, instead of their chromatic properties, for uniquely characterizing each point, by forming a specific geometrical descriptor. This paper presents a comparative study reviewing variations of geometry-based, descriptor-oriented registration techniques, as well as conventional, exhaustive, intensity-based methods for aligning three-dimensional (3D) CT data pairs. In this context, three general image registration frameworks were examined: a geometry-based methodology featuring three distinct geometrical descriptors, an intensity-based methodology using three different similarity metrics, as well as the commonly used Iterative Closest Point algorithm. All techniques were applied on a total of thirty 3D CT data pairs with both known and unknown initial spatial differences. After an extensive qualitative and quantitative assessment, it was concluded that the proposed geometry-based registration framework performed similarly to the examined exhaustive registration techniques. In addition, geometry-based methods dramatically improved processing time over conventional exhaustive registration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Automated quantitative Rb-82 3D PET/CT myocardial perfusion imaging: normal limits and correlation with invasive coronary angiography.

    PubMed

    Nakazato, Ryo; Berman, Daniel S; Dey, Damini; Le Meunier, Ludovic; Hayes, Sean W; Fermin, Jimmy S; Cheng, Victor Y; Thomson, Louise E J; Friedman, John D; Germano, Guido; Slomka, Piotr J

    2012-04-01

    We aimed to characterize normal limits and to determine the diagnostic accuracy for an automated quantification of 3D 82-Rubidium (Rb-82) PET/CT myocardial perfusion imaging (MPI). We studied 125 consecutive patients undergoing Rb-82 PET/CT MPI, including patients with suspected coronary artery disease (CAD) and invasive coronary angiography, and 42 patients with a low likelihood (LLk) of CAD. Normal limits for perfusion and function were derived from LLk patients. QPET software was used to quantify perfusion abnormality at rest and stress expressed as total perfusion deficit (TPD). Relative perfusion databases did not differ in any of the 17 segments between males and females. The areas under the receiver operating characteristic curve for detection of CAD were 0.86 for identification of ≥50% and ≥70% stenosis. The sensitivity/specificity was 86%/86% for detecting ≥50% stenosis and 93%/77% for ≥70% stenosis, respectively. In regard to normal limits, mean rest and stress left ventricular ejection fraction (LVEF) were 67% ± 10% and 75% ± 9%, respectively. Mean transient ischemic dilation ratio was 1.06 ± 0.14 and mean increase in LVEF with stress was 7.4% ± 6.1% (95th percentile of 0%). Normal limits have been established for 3D Rb-82 PET/CT analysis with QPET software. Fully automated quantification of myocardial perfusion PET data shows high diagnostic accuracy for detecting obstructive CAD.

  7. Parametric modeling of the intervertebral disc space in 3D: application to CT images of the lumbar spine.

    PubMed

    Korez, Robert; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž

    2014-10-01

    Gradual degeneration of intervertebral discs of the lumbar spine is one of the most common causes of low back pain. Although conservative treatment for low back pain may provide relief to most individuals, surgical intervention may be required for individuals with significant continuing symptoms, which is usually performed by replacing the degenerated intervertebral disc with an artificial implant. For designing implants with good bone contact and continuous force distribution, the morphology of the intervertebral disc space and vertebral body endplates is of considerable importance. In this study, we propose a method for parametric modeling of the intervertebral disc space in three dimensions (3D) and show its application to computed tomography (CT) images of the lumbar spine. The initial 3D model of the intervertebral disc space is generated according to the superquadric approach and therefore represented by a truncated elliptical cone, which is initialized by parameters obtained from 3D models of adjacent vertebral bodies. In an optimization procedure, the 3D model of the intervertebral disc space is incrementally deformed by adding parameters that provide a more detailed morphometric description of the observed shape, and aligned to the observed intervertebral disc space in the 3D image. By applying the proposed method to CT images of 20 lumbar spines, the shape and pose of each of the 100 intervertebral disc spaces were represented by a 3D parametric model. The resulting mean (±standard deviation) accuracy of modeling was 1.06±0.98mm in terms of radial Euclidean distance against manually defined ground truth points, with the corresponding success rate of 93% (i.e. 93 out of 100 intervertebral disc spaces were modeled successfully). As the resulting 3D models provide a description of the shape of intervertebral disc spaces in a complete parametric form, morphometric analysis was straightforwardly enabled and allowed the computation of the corresponding

  8. A new concept for intraoperative matching of 3D ultrasound and CT.

    PubMed

    Schorr, O; Wörn, H

    2001-01-01

    Matching of ultrasound images with CT or MRI scans is an awkward and unsatisfactory task when using conventional methods. Wide ranging differences in modality of ultrasound and CT/MRI require new techniques to be explored for successful alignment. Ultrasound images characteristically show comparable high noise ratio due to scattering inside the region of interest and the surrounding area. Additionally, shadowing and tissue dependent echo response time produce geometric artifacts. These image distortions are sophisticated to recover. Though image quality and geometric relationship are poor, ultrasound images show the potential for fast, low-cost, non-invasive and flexible image acquisition, predestinated for intraoperative application. The fusion of intraoperative ultrasound and preoperatively acquired CT/MRI images provides both, geometric invariance and flexible fast image acquisition, merging in a powerful tool for augmented three dimensional reality. In this paper we describe a completely new concept for alignment with abstaining from direct rigid or elastic matching of ultrasound to CT/MRI. Instead of placing those images in direct relationship, our approach involves a simulation of ultrasound wave behavior in order to predict B-mode images.

  9. Combining population and patient-specific characteristics for prostate segmentation on 3D CT images

    NASA Astrophysics Data System (ADS)

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Tade, Funmilayo; Schuster, David M.; Fei, Baowei

    2016-03-01

    Prostate segmentation on CT images is a challenging task. In this paper, we explore the population and patient-specific characteristics for the segmentation of the prostate on CT images. Because population learning does not consider the inter-patient variations and because patient-specific learning may not perform well for different patients, we are combining the population and patient-specific information to improve segmentation performance. Specifically, we train a population model based on the population data and train a patient-specific model based on the manual segmentation on three slice of the new patient. We compute the similarity between the two models to explore the influence of applicable population knowledge on the specific patient. By combining the patient-specific knowledge with the influence, we can capture the population and patient-specific characteristics to calculate the probability of a pixel belonging to the prostate. Finally, we smooth the prostate surface according to the prostate-density value of the pixels in the distance transform image. We conducted the leave-one-out validation experiments on a set of CT volumes from 15 patients. Manual segmentation results from a radiologist serve as the gold standard for the evaluation. Experimental results show that our method achieved an average DSC of 85.1% as compared to the manual segmentation gold standard. This method outperformed the population learning method and the patient-specific learning approach alone. The CT segmentation method can have various applications in prostate cancer diagnosis and therapy.

  10. Combining Population and Patient-Specific Characteristics for Prostate Segmentation on 3D CT Images

    PubMed Central

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Tade, Funmilayo; Schuster, David M.; Fei, Baowei

    2016-01-01

    Prostate segmentation on CT images is a challenging task. In this paper, we explore the population and patient-specific characteristics for the segmentation of the prostate on CT images. Because population learning does not consider the inter-patient variations and because patient-specific learning may not perform well for different patients, we are combining the population and patient-specific information to improve segmentation performance. Specifically, we train a population model based on the population data and train a patient-specific model based on the manual segmentation on three slice of the new patient. We compute the similarity between the two models to explore the influence of applicable population knowledge on the specific patient. By combining the patient-specific knowledge with the influence, we can capture the population and patient-specific characteristics to calculate the probability of a pixel belonging to the prostate. Finally, we smooth the prostate surface according to the prostate-density value of the pixels in the distance transform image. We conducted the leave-one-out validation experiments on a set of CT volumes from 15 patients. Manual segmentation results from a radiologist serve as the gold standard for the evaluation. Experimental results show that our method achieved an average DSC of 85.1% as compared to the manual segmentation gold standard. This method outperformed the population learning method and the patient-specific learning approach alone. The CT segmentation method can have various applications in prostate cancer diagnosis and therapy. PMID:27660382

  11. Combining Population and Patient-Specific Characteristics for Prostate Segmentation on 3D CT Images.

    PubMed

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Tade, Funmilayo; Schuster, David M; Fei, Baowei

    2016-02-27

    Prostate segmentation on CT images is a challenging task. In this paper, we explore the population and patient-specific characteristics for the segmentation of the prostate on CT images. Because population learning does not consider the inter-patient variations and because patient-specific learning may not perform well for different patients, we are combining the population and patient-specific information to improve segmentation performance. Specifically, we train a population model based on the population data and train a patient-specific model based on the manual segmentation on three slice of the new patient. We compute the similarity between the two models to explore the influence of applicable population knowledge on the specific patient. By combining the patient-specific knowledge with the influence, we can capture the population and patient-specific characteristics to calculate the probability of a pixel belonging to the prostate. Finally, we smooth the prostate surface according to the prostate-density value of the pixels in the distance transform image. We conducted the leave-one-out validation experiments on a set of CT volumes from 15 patients. Manual segmentation results from a radiologist serve as the gold standard for the evaluation. Experimental results show that our method achieved an average DSC of 85.1% as compared to the manual segmentation gold standard. This method outperformed the population learning method and the patient-specific learning approach alone. The CT segmentation method can have various applications in prostate cancer diagnosis and therapy.

  12. Micro-CT for the quantification of 3D voids within damaged structures

    SciTech Connect

    Patterson, Brian M; Hamilton, Christopher E; Cerreta, Ellen K; Dennis - Koller, Darcie; Bronkhorst, C. A.; Hansen, B. L.

    2011-01-26

    Micro X-ray Computed Tomography (MXCT) is widely used in the materials community to examine the internal structure of materials for voids and cracks due to damage or casting, or other defects. Most research in this area focuses on the qualitative aspect of the image, simply answering; Are there voids present? Here we present an ongoing study of the quantified incipient spall voids in Cu with different grain sizes, using a gas gun with various velocities. Data analysis packages for MXCT are just now becoming able to dimensionally measure and produce statistics on the voids-present. In order to make the size of the features in the 3D image quantifiable, the question, how many radiographs are required to render the object dimensionally accurate in 3D, must be answered. A series of data sets has been coUected, varying the number of radiographs collected in order to determine the appropriate number required.

  13. Iterative mesh transformation for 3D segmentation of livers with cancers in CT images.

    PubMed

    Lu, Difei; Wu, Yin; Harris, Gordon; Cai, Wenli

    2015-07-01

    Segmentation of diseased liver remains a challenging task in clinical applications due to the high inter-patient variability in liver shapes, sizes and pathologies caused by cancers or other liver diseases. In this paper, we present a multi-resolution mesh segmentation algorithm for 3D segmentation of livers, called iterative mesh transformation that deforms the mesh of a region-of-interest (ROI) in a progressive manner by iterations between mesh transformation and contour optimization. Mesh transformation deforms the 3D mesh based on the deformation transfer model that searches the optimal mesh based on the affine transformation subjected to a set of constraints of targeting vertices. Besides, contour optimization searches the optimal transversal contours of the ROI by applying the dynamic-programming algorithm to the intersection polylines of the 3D mesh on 2D transversal image planes. The initial constraint set for mesh transformation can be defined by a very small number of targeting vertices, namely landmarks, and progressively updated by adding the targeting vertices selected from the optimal transversal contours calculated in contour optimization. This iterative 3D mesh transformation constrained by 2D optimal transversal contours provides an efficient solution to a progressive approximation of the mesh of the targeting ROI. Based on this iterative mesh transformation algorithm, we developed a semi-automated scheme for segmentation of diseased livers with cancers using as little as five user-identified landmarks. The evaluation study demonstrates that this semi-automated liver segmentation scheme can achieve accurate and reliable segmentation results with significant reduction of interaction time and efforts when dealing with diseased liver cases.

  14. Iterative Mesh Transformation for 3D Segmentation of Livers with Cancers in CT Images

    PubMed Central

    Lu, Difei; Wu, Yin; Harris, Gordon; Cai, Wenli

    2015-01-01

    Segmentation of diseased liver remains a challenging task in clinical applications due to the high inter-patient variability in liver shapes, sizes and pathologies caused by cancers or other liver diseases. In this paper, we present a multi-resolution mesh segmentation algorithm for 3D segmentation of livers, called iterative mesh transformation that deforms the mesh of a region-of-interest (ROI) in a progressive manner by iterations between mesh transformation and contour optimization. Mesh transformation deforms the 3D mesh based on the deformation transfer model that searches the optimal mesh based on the affine transformation subjected to a set of constraints of targeting vertices. Besides, contour optimization searches the optimal transversal contours of the ROI by applying the dynamic-programming algorithm to the intersection polylines of the 3D mesh on 2D transversal image planes. The initial constraint set for mesh transformation can be defined by a very small number of targeting vertices, namely landmarks, and progressively updated by adding the targeting vertices selected from the optimal transversal contours calculated in contour optimization. This iterative 3D mesh transformation constrained by 2D optimal transversal contours provides an efficient solution to a progressive approximation of the mesh of the targeting ROI. Based on this iterative mesh transformation algorithm, we developed a semi-automated scheme for segmentation of diseased livers with cancers using as little as five user-identified landmarks. The evaluation study demonstrates that this semiautomated liver segmentation scheme can achieve accurate and reliable segmentation results with significant reduction of interaction time and efforts when dealing with diseased liver cases. PMID:25728595

  15. Twin robotic x-ray system for 2D radiographic and 3D cone-beam CT imaging

    NASA Astrophysics Data System (ADS)

    Fieselmann, Andreas; Steinbrener, Jan; Jerebko, Anna K.; Voigt, Johannes M.; Scholz, Rosemarie; Ritschl, Ludwig; Mertelmeier, Thomas

    2016-03-01

    In this work, we provide an initial characterization of a novel twin robotic X-ray system. This system is equipped with two motor-driven telescopic arms carrying X-ray tube and flat-panel detector, respectively. 2D radiographs and fluoroscopic image sequences can be obtained from different viewing angles. Projection data for 3D cone-beam CT reconstruction can be acquired during simultaneous movement of the arms along dedicated scanning trajectories. We provide an initial evaluation of the 3D image quality based on phantom scans and clinical images. Furthermore, initial evaluation of patient dose is conducted. The results show that the system delivers high image quality for a range of medical applications. In particular, high spatial resolution enables adequate visualization of bone structures. This system allows 3D X-ray scanning of patients in standing and weight-bearing position. It could enable new 2D/3D imaging workflows in musculoskeletal imaging and improve diagnosis of musculoskeletal disorders.

  16. Commissioning a CT-compatible LDR tandem and ovoid applicator using Monte Carlo calculation and 3D dosimetry.

    PubMed

    Adamson, Justus; Newton, Joseph; Yang, Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana

    2012-07-01

    To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T&O) applicator using Monte Carlo calculation and 3D dosimetry. For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 × 10(9) photon histories from a (137)Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for (137)Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE(®) dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5-8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5° increments, and a 3D distribution was reconstructed with a (0.05 cm)(3) isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T&O implant plan. The systematic difference in bucket angle relative to the nominal ovoid angle (105°) was 3.1°-4.7°. A systematic difference in bucket angle of 1°, 5°, and 10° caused a 1% ± 0.1%, 1.7% ± 0.4%, and 2.6% ± 0.7% increase in rectal dose, respectively, with smaller effect to dose to Point A, bladder

  17. Commissioning a CT-compatible LDR tandem and ovoid applicator using Monte Carlo calculation and 3D dosimetry

    SciTech Connect

    Adamson, Justus; Newton, Joseph; Yang Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana

    2012-07-15

    Purpose: To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T and O) applicator using Monte Carlo calculation and 3D dosimetry. Methods: For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 Multiplication-Sign 10{sup 9} photon histories from a {sup 137}Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for {sup 137}Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE{sup Registered-Sign} dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5-8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5 Degree-Sign increments, and a 3D distribution was reconstructed with a (0.05 cm){sup 3} isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T and O implant plan. Results: The systematic difference in bucket angle relative to the nominal ovoid angle (105 Degree-Sign ) was 3.1 Degree-Sign -4.7 Degree-Sign . A systematic difference in bucket angle of 1 Degree-Sign , 5 Degree-Sign , and

  18. Positioning evaluation of corrective osteotomy for the malunited radius: 3-D CT versus 2-D radiographs.

    PubMed

    Vroemen, Joy C; Dobbe, Johannes G G; Strackee, Simon D; Streekstra, Geert J

    2013-02-01

    The authors retrospectively investigated the postoperative position of the distal radius after a corrective osteotomy using 2-dimensional (2-D) and 3-dimensional (3-D) imaging techniques to determine whether malposition correlates with clinical outcome. Twenty-five patients who underwent a corrective osteotomy were available for follow-up. The residual positioning errors of the distal end were determined retrospectively using standard 2-D radiographs and 3-D computed tomography evaluations based on a scan of both forearms, with the contralateral healthy radius serving as reference. For 3-D analysis, use of an anatomical coordinate system for each reference bone allowed the authors to express the residual malalignment parameters in displacements (Δx, Δy, Δz) and rotations (Δφx, Δφy, Δφz) for aligning the affected bone in a standardized way with the corresponding reference bone. The authors investigated possible correlations between malalignment parameters and clinical outcome using patients' questionnaires. Two-dimensional radiographic evaluation showed a radial inclination of 24.9°±6.8°, a palmar tilt of 4.5°±8.6°, and an ulnar variance of 0.8±1.7 mm. With 3-D analysis, residual displacements were 2.6±3 (Δx), 2.4±3 (Δy), and -2.2±4 (Δz) mm. Residual rotations were -6.2°±10° (Δφx), 0.3°±7° (Δφy), and -5.1°±10° (Δφz). The large standard deviation is indicative of persistent malalignment in individual cases. Statistically significant correlations were found between 3-D rotational deficits and clinical outcome but not between 2-D evaluation parameters. Considerable residual malalignments and statistically significant correlations between malalignment parameters and clinical outcome confirm the need for better positioning techniques.

  19. Phantom investigation of 3D motion-dependent volume aliasing during CT simulation for radiation therapy planning

    PubMed Central

    Tanyi, James A; Fuss, Martin; Varchena, Vladimir; Lancaster, Jack L; Salter, Bill J

    2007-01-01

    Purpose To quantify volumetric and positional aliasing during non-gated fast- and slow-scan acquisition CT in the presence of 3D target motion. Methods Single-slice fast, single-slice slow, and multi-slice fast scan helical CTs were acquired of dynamic spherical targets (1 and 3.15 cm in diameter), embedded in an anthropomorphic phantom. 3D target motions typical of clinically observed tumor motion parameters were investigated. Motion excursions included ± 5, ± 10, and ± 15 mm displacements in the S-I direction synchronized with constant displacements of ± 5 and ± 2 mm in the A-P and lateral directions, respectively. For each target, scan technique, and motion excursion, eight different initial motion-to-scan phase relationships were investigated. Results An anticipated general trend of target volume overestimation was observed. The mean percentage overestimation of the true physical target volume typically increased with target motion amplitude and decreasing target diameter. Slow-scan percentage overestimations were larger, and better approximated the time-averaged motion envelope, as opposed to fast-scans. Motion induced centroid misrepresentation was greater in the S-I direction for fast-scan techniques, and transaxial direction for the slow-scan technique. Overestimation is fairly uniform for slice widths < 5 mm, beyond which there is gross overestimation. Conclusion Non-gated CT imaging of targets describing clinically relevant, 3D motion results in aliased overestimation of the target volume and misrepresentation of centroid location, with little or no correlation between the physical target geometry and the CT-generated target geometry. Slow-scan techniques are a practical method for characterizing time-averaged target position. Fast-scan techniques provide a more reliable, albeit still distorted, target margin. PMID:17319965

  20. 3D printing for orthopedic applications: from high resolution cone beam CT images to life size physical models

    NASA Astrophysics Data System (ADS)

    Jackson, Amiee; Ray, Lawrence A.; Dangi, Shusil; Ben-Zikri, Yehuda K.; Linte, Cristian A.

    2017-03-01

    With increasing resolution in image acquisition, the project explores capabilities of printing toward faithfully reflecting detail and features depicted in medical images. To improve safety and efficiency of orthopedic surgery and spatial conceptualization in training and education, this project focused on generating virtual models of orthopedic anatomy from clinical quality computed tomography (CT) image datasets and manufacturing life-size physical models of the anatomy using 3D printing tools. Beginning with raw micro CT data, several image segmentation techniques including thresholding, edge recognition, and region-growing algorithms available in packages such as ITK-SNAP, MITK, or Mimics, were utilized to separate bone from surrounding soft tissue. After converting the resulting data to a standard 3D printing format, stereolithography (STL), the STL file was edited using Meshlab, Netfabb, and Meshmixer. The editing process was necessary to ensure a fully connected surface (no loose elements), positive volume with manifold geometry (geometry possible in the 3D physical world), and a single, closed shell. The resulting surface was then imported into a "slicing" software to scale and orient for printing on a Flashforge Creator Pro. In printing, relationships between orientation, print bed volume, model quality, material use and cost, and print time were considered. We generated anatomical models of the hand, elbow, knee, ankle, and foot from both low-dose high-resolution cone-beam CT images acquired using the soon to be released scanner developed by Carestream, as well as scaled models of the skeletal anatomy of the arm and leg, together with life-size models of the hand and foot.

  1. From 3D to 4D: Integration of temporal information into CT angiography studies.

    PubMed

    Haubenreisser, Holger; Bigdeli, Amir; Meyer, Mathias; Kremer, Thomas; Riester, Thomas; Kneser, Ulrich; Schoenberg, Stefan O; Henzler, Thomas

    2015-12-01

    CT angiography is the current clinical standard for the imaging many vascular illnesses. This is traditionally done with a single arterial contrast phase. However, advances in CT technology allow for a dynamic acquisition of the contrast bolus, thus adding temporal information to the examination. The aim of this article is to highlight the clinical possibilities of dynamic CTA using 2 examples. The accuracy of the detection and quantification of stenosis in patients with peripheral arterial occlusive disease, especially in stadium III and IV, is significantly improved when performing dynamic CTA examinations. The post-interventional follow-up of examinations of EVAR benefit from dynamic information, allowing for a higher sensitivity and specificity, as well as allowing more accurate classification of potential endoleaks. The described radiation dose for these dynamic examinations is low, but this can be further optimized by using lower tube voltages. There are a multitude of applications for dynamic CTA that need to be further explored in future studies.

  2. CT scans and 3D reconstructions of Florida manatee (Trichechus manatus latirostris) heads and ear bones.

    PubMed

    Chapla, Marie E; Nowacek, Douglas P; Rommel, Sentiel A; Sadler, Valerie M

    2007-06-01

    The auditory anatomy of the Florida manatee (Trichechus manatus latirostris) was investigated using computerized tomography (CT), three-dimensional reconstructions, and traditional dissection of heads removed during necropsy. The densities (kg/m3) of the soft tissues of the head were measured directly using the displacement method and those of the soft tissues and bone were calculated from CT measurements (Hounsfield units). The manatee's fatty tissue was significantly less dense than the other soft tissues within the head (p<0.05). The squamosal bone was significantly less dense than the other bones of the head (p<0.05). Measurements of the ear bones (tympanic, periotic, malleus, incus, and stapes) collected during dissection revealed that the ossicular chain was overly massive for the mass of the tympanoperiotic complex.

  3. 3D segmentation of abdominal aorta from CT-scan and MR images.

    PubMed

    Duquette, Anthony Adam; Jodoin, Pierre-Marc; Bouchot, Olivier; Lalande, Alain

    2012-06-01

    We designed a generic method for segmenting the aneurismal sac of an abdominal aortic aneurysm (AAA) both from multi-slice MR and CT-scan examinations. It is a semi-automatic method requiring little human intervention and based on graph cut theory to segment the lumen interface and the aortic wall of AAAs. Our segmentation method works independently on MRI and CT-scan volumes and has been tested on a 44 patient dataset and 10 synthetic images. Segmentation and maximum diameter estimation were compared to manual tracing from 4 experts. An inter-observer study was performed in order to measure the variability range of a human observer. Based on three metrics (the maximum aortic diameter, the volume overlap and the Hausdorff distance) the variability of the results obtained by our method is shown to be similar to that of a human operator, both for the lumen interface and the aortic wall. As will be shown, the average distance obtained with our method is less than one standard deviation away from each expert, both for healthy subjects and for patients with AAA. Our semi-automatic method provides reliable contours of the abdominal aorta from CT-scan or MRI, allowing rapid and reproducible evaluations of AAA.

  4. Testing hypotheses of bat baculum function with 3D models derived from microCT

    PubMed Central

    Herdina, Anna Nele; Kelly, Diane A; Jahelková, Helena; Lina, Peter H C; Horáček, Ivan; Metscher, Brian D

    2015-01-01

    The baculum (os penis) has been extensively studied as a taxon-specific character in bats and other mammals but its mechanical function is still unclear. There is a wide consensus in the literature that the baculum is probably a sexually selected character. Using a novel approach combining postmortem manipulation and three-dimensional (3D) imaging, we tested two functional hypotheses in the common noctule bat Nyctalus noctula, the common pipistrelle Pipistrellus pipistrellus, and Nathusius’ pipistrelle Pipistrellus nathusii: (i) whether the baculum can protect the distal urethra and urethral opening from compression during erection and copulation; and (ii) whether the baculum and corpora cavernosa form a functional unit to support both the penile shaft and the more distal glans tip. In freshly dead or frozen and thawed bats, we compared flaccid penises with artificially ‘erect’ penises that were inflated with 10% formalin. Penises were stained with alcoholic iodine and imaged with a lab-based high-resolution x-ray microtomography system. Analysis of the 3D images enabled us to compare the changes in relative positions of the baculum, corpora cavernosa, urethra, and corpus spongiosum with one another between flaccid and ‘erect’ penises. Our results support both functional hypotheses, indicating that the baculum probably performs two different roles during erection. Our approach should prove valuable for comparing and testing the functions of different baculum morphologies in bats and other mammals. Moreover, we have validated an essential component of the groundwork necessary to extend this approach with finite element analysis for quantitative 3D biomechanical modeling of penis function. PMID:25655647

  5. Toward acquiring comprehensive radiosurgery field commissioning data using the PRESAGE®/ optical-CT 3D dosimetry system

    NASA Astrophysics Data System (ADS)

    Clift, Corey; Thomas, Andrew; Adamovics, John; Chang, Zheng; Das, Indra; Oldham, Mark

    2010-03-01

    Achieving accurate small field dosimetry is challenging. This study investigates the utility of a radiochromic plastic PRESAGE® read with optical-CT for the acquisition of radiosurgery field commissioning data from a Novalis Tx system with a high-definition multileaf collimator (HDMLC). Total scatter factors (Sc, p), beam profiles, and penumbrae were measured for five different radiosurgery fields (5, 10, 20, 30 and 40 mm) using a commercially available optical-CT scanner (OCTOPUS, MGS Research). The percent depth dose (PDD), beam profile and penumbra of the 10 mm field were also measured using a higher resolution in-house prototype CCD-based scanner. Gafchromic EBT® film was used for independent verification. Measurements of Sc, p made with PRESAGE® and film agreed with mini-ion chamber commissioning data to within 4% for every field (range 0.2-3.6% for PRESAGE®, and 1.6-3.6% for EBT). PDD, beam profile and penumbra measurements made with the two PRESAGE®/optical-CT systems and film showed good agreement with the high-resolution diode commissioning measurements with a competitive resolution (0.5 mm pixels). The in-house prototype optical-CT scanner allowed much finer resolution compared with previous applications of PRESAGE®. The advantages of the PRESAGE® system for small field dosimetry include 3D measurements, negligible volume averaging, directional insensitivity, an absence of beam perturbations, energy and dose rate independence.

  6. 2D and 3D Terahertz Imaging and X-Rays CT for Sigillography Study

    NASA Astrophysics Data System (ADS)

    Fabre, M.; Durand, R.; Bassel, L.; Recur, B.; Balacey, H.; Bou Sleiman, J.; Perraud, J.-B.; Mounaix, P.

    2017-04-01

    Seals are part of our cultural heritage but the study of these objects is limited because of their fragility. Terahertz and X-Ray imaging are used to analyze a collection of wax seals from the fourteenth to eighteenth centuries. In this work, both techniques are compared in order to discuss their advantages and limits and their complementarity for conservation state study of the samples. Thanks to 3D analysis and reconstructions, defects and fractures are detected with an estimation of their depth position. The path from the parchment tongue inside the seals is also detected.

  7. 2D and 3D Terahertz Imaging and X-Rays CT for Sigillography Study

    NASA Astrophysics Data System (ADS)

    Fabre, M.; Durand, R.; Bassel, L.; Recur, B.; Balacey, H.; Bou Sleiman, J.; Perraud, J.-B.; Mounaix, P.

    2017-01-01

    Seals are part of our cultural heritage but the study of these objects is limited because of their fragility. Terahertz and X-Ray imaging are used to analyze a collection of wax seals from the fourteenth to eighteenth centuries. In this work, both techniques are compared in order to discuss their advantages and limits and their complementarity for conservation state study of the samples. Thanks to 3D analysis and reconstructions, defects and fractures are detected with an estimation of their depth position. The path from the parchment tongue inside the seals is also detected.

  8. Technical note: Reliability of Suchey-Brooks and Buckberry-Chamberlain methods on 3D visualizations from CT and laser scans.

    PubMed

    Villa, Chiara; Buckberry, Jo; Cattaneo, Cristina; Lynnerup, Niels

    2013-05-01

    Previous studies have reported that the ageing method of Suchey-Brooks (pubic bone) and some of the features applied by Lovejoy et al. and Buckberry-Chamberlain (auricular surface) can be confidently performed on 3D visualizations from CT-scans. In this study, seven observers applied the Suchey-Brooks and the Buckberry-Chamberlain methods on 3D visualizations based on CT-scans and, for the first time, on 3D visualizations from laser scans. We examined how the bone features can be evaluated on 3D visualizations and whether the different modalities (direct observations of bones, 3D visualization from CT-scan and from laser scans) are alike to different observers. We found the best inter-observer agreement for the bones versus 3D visualizations, with the highest values for the auricular surface. Between the 3D modalities, less variability was obtained for the 3D laser visualizations. Fair inter-observer agreement was obtained in the evaluation of the pubic bone in all modalities. In 3D visualizations of the auricular surfaces, transverse organization and apical changes could be evaluated, although with high inter-observer variability; micro-, macroporosity and surface texture were very difficult to score. In conclusion, these methods were developed for dry bones, where they perform best. The Suchey-Brooks method can be applied on 3D visualizations from CT or laser, but with less accuracy than on dry bone. The Buckberry-Chamberlain method should be modified before application on 3D visualizations. Future investigation should focus on a different approach and different features: 3D laser scans could be analyzed with mathematical approaches and sub-surface features should be explored on CT-scans.

  9. 3D In Vivo Dosimetry Using Megavoltage Cone-Beam CT and EPID Dosimetry

    SciTech Connect

    Elmpt, Wouter van Nijsten, Sebastiaan; Petit, Steven; Mijnheer, Ben; Lambin, Philippe; Dekker, Andre

    2009-04-01

    Purpose: To develop a method that reconstructs, independently of previous (planning) information, the dose delivered to patients by combining in-room imaging with transit dose measurements during treatment. Methods and Materials: A megavoltage cone-beam CT scan of the patient anatomy was acquired with the patient in treatment position. During treatment, delivered fields were measured behind the patient with an electronic portal imaging device. The dose information in these images was back-projected through the cone-beam CT scan and used for Monte Carlo simulation of the dose distribution inside the cone-beam CT scan. Validation was performed using various phantoms for conformal and IMRT plans. Clinical applicability is shown for a head-and-neck cancer patient treated with IMRT. Results: For single IMRT beams and a seven-field IMRT step-and-shoot plan, the dose distribution was reconstructed within 3%/3mm compared with the measured or planned dose. A three-dimensional conformal plan, verified using eight point-dose measurements, resulted in a difference of 1.3 {+-} 3.3% (1 SD) compared with the reconstructed dose. For the patient case, planned and reconstructed dose distribution was within 3%/3mm for about 95% of the points within the 20% isodose line. Reconstructed mean dose values, obtained from dose-volume histograms, were within 3% of prescribed values for target volumes and normal tissues. Conclusions: We present a new method that verifies the dose delivered to a patient by combining in-room imaging with the transit dose measured during treatment. This verification procedure opens possibilities for offline adaptive radiotherapy and dose-guided radiotherapy strategies taking into account the dose distribution delivered during treatment sessions.

  10. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    PubMed

    Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

    2013-12-01

    The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime

  11. Use of the FLUKA Monte Carlo code for 3D patient-specific dosimetry on PET-CT and SPECT-CT images*

    PubMed Central

    Botta, F; Mairani, A; Hobbs, R F; Vergara Gil, A; Pacilio, M; Parodi, K; Cremonesi, M; Coca Pérez, M A; Di Dia, A; Ferrari, M; Guerriero, F; Battistoni, G; Pedroli, G; Paganelli, G; Torres Aroche, L A; Sgouros, G

    2014-01-01

    Patient-specific absorbed dose calculation for nuclear medicine therapy is a topic of increasing interest. 3D dosimetry at the voxel level is one of the major improvements for the development of more accurate calculation techniques, as compared to the standard dosimetry at the organ level. This study aims to use the FLUKA Monte Carlo code to perform patient-specific 3D dosimetry through direct Monte Carlo simulation on PET-CT and SPECT-CT images. To this aim, dedicated routines were developed in the FLUKA environment. Two sets of simulations were performed on model and phantom images. Firstly, the correct handling of PET and SPECT images was tested under the assumption of homogeneous water medium by comparing FLUKA results with those obtained with the voxel kernel convolution method and with other Monte Carlo-based tools developed to the same purpose (the EGS-based 3D-RD software and the MCNP5-based MCID). Afterwards, the correct integration of the PET/SPECT and CT information was tested, performing direct simulations on PET/CT images for both homogeneous (water) and non-homogeneous (water with air, lung and bone inserts) phantoms. Comparison was performed with the other Monte Carlo tools performing direct simulation as well. The absorbed dose maps were compared at the voxel level. In the case of homogeneous water, by simulating 108 primary particles a 2% average difference with respect to the kernel convolution method was achieved; such difference was lower than the statistical uncertainty affecting the FLUKA results. The agreement with the other tools was within 3–4%, partially ascribable to the differences among the simulation algorithms. Including the CT-based density map, the average difference was always within 4% irrespective of the medium (water, air, bone), except for a maximum 6% value when comparing FLUKA and 3D-RD in air. The results confirmed that the routines were properly developed, opening the way for the use of FLUKA for patient-specific, image

  12. Use of the FLUKA Monte Carlo code for 3D patient-specific dosimetry on PET-CT and SPECT-CT images

    NASA Astrophysics Data System (ADS)

    Botta, F.; Mairani, A.; Hobbs, R. F.; Vergara Gil, A.; Pacilio, M.; Parodi, K.; Cremonesi, M.; Coca Pérez, M. A.; Di Dia, A.; Ferrari, M.; Guerriero, F.; Battistoni, G.; Pedroli, G.; Paganelli, G.; Torres Aroche, L. A.; Sgouros, G.

    2013-11-01

    Patient-specific absorbed dose calculation for nuclear medicine therapy is a topic of increasing interest. 3D dosimetry at the voxel level is one of the major improvements for the development of more accurate calculation techniques, as compared to the standard dosimetry at the organ level. This study aims to use the FLUKA Monte Carlo code to perform patient-specific 3D dosimetry through direct Monte Carlo simulation on PET-CT and SPECT-CT images. To this aim, dedicated routines were developed in the FLUKA environment. Two sets of simulations were performed on model and phantom images. Firstly, the correct handling of PET and SPECT images was tested under the assumption of homogeneous water medium by comparing FLUKA results with those obtained with the voxel kernel convolution method and with other Monte Carlo-based tools developed to the same purpose (the EGS-based 3D-RD software and the MCNP5-based MCID). Afterwards, the correct integration of the PET/SPECT and CT information was tested, performing direct simulations on PET/CT images for both homogeneous (water) and non-homogeneous (water with air, lung and bone inserts) phantoms. Comparison was performed with the other Monte Carlo tools performing direct simulation as well. The absorbed dose maps were compared at the voxel level. In the case of homogeneous water, by simulating 108 primary particles a 2% average difference with respect to the kernel convolution method was achieved; such difference was lower than the statistical uncertainty affecting the FLUKA results. The agreement with the other tools was within 3-4%, partially ascribable to the differences among the simulation algorithms. Including the CT-based density map, the average difference was always within 4% irrespective of the medium (water, air, bone), except for a maximum 6% value when comparing FLUKA and 3D-RD in air. The results confirmed that the routines were properly developed, opening the way for the use of FLUKA for patient-specific, image

  13. Use of the FLUKA Monte Carlo code for 3D patient-specific dosimetry on PET-CT and SPECT-CT images.

    PubMed

    Botta, F; Mairani, A; Hobbs, R F; Vergara Gil, A; Pacilio, M; Parodi, K; Cremonesi, M; Coca Pérez, M A; Di Dia, A; Ferrari, M; Guerriero, F; Battistoni, G; Pedroli, G; Paganelli, G; Torres Aroche, L A; Sgouros, G

    2013-11-21

    Patient-specific absorbed dose calculation for nuclear medicine therapy is a topic of increasing interest. 3D dosimetry at the voxel level is one of the major improvements for the development of more accurate calculation techniques, as compared to the standard dosimetry at the organ level. This study aims to use the FLUKA Monte Carlo code to perform patient-specific 3D dosimetry through direct Monte Carlo simulation on PET-CT and SPECT-CT images. To this aim, dedicated routines were developed in the FLUKA environment. Two sets of simulations were performed on model and phantom images. Firstly, the correct handling of PET and SPECT images was tested under the assumption of homogeneous water medium by comparing FLUKA results with those obtained with the voxel kernel convolution method and with other Monte Carlo-based tools developed to the same purpose (the EGS-based 3D-RD software and the MCNP5-based MCID). Afterwards, the correct integration of the PET/SPECT and CT information was tested, performing direct simulations on PET/CT images for both homogeneous (water) and non-homogeneous (water with air, lung and bone inserts) phantoms. Comparison was performed with the other Monte Carlo tools performing direct simulation as well. The absorbed dose maps were compared at the voxel level. In the case of homogeneous water, by simulating 10(8) primary particles a 2% average difference with respect to the kernel convolution method was achieved; such difference was lower than the statistical uncertainty affecting the FLUKA results. The agreement with the other tools was within 3–4%, partially ascribable to the differences among the simulation algorithms. Including the CT-based density map, the average difference was always within 4% irrespective of the medium (water, air, bone), except for a maximum 6% value when comparing FLUKA and 3D-RD in air. The results confirmed that the routines were properly developed, opening the way for the use of FLUKA for patient-specific, image

  14. Efficient and robust 3D CT image reconstruction based on total generalized variation regularization using the alternating direction method.

    PubMed

    Chen, Jianlin; Wang, Linyuan; Yan, Bin; Zhang, Hanming; Cheng, Genyang

    2015-01-01

    Iterative reconstruction algorithms for computed tomography (CT) through total variation regularization based on piecewise constant assumption can produce accurate, robust, and stable results. Nonetheless, this approach is often subject to staircase artefacts and the loss of fine details. To overcome these shortcomings, we introduce a family of novel image regularization penalties called total generalized variation (TGV) for the effective production of high-quality images from incomplete or noisy projection data for 3D reconstruction. We propose a new, fast alternating direction minimization algorithm to solve CT image reconstruction problems through TGV regularization. Based on the theory of sparse-view image reconstruction and the framework of augmented Lagrange function method, the TGV regularization term has been introduced in the computed tomography and is transformed into three independent variables of the optimization problem by introducing auxiliary variables. This new algorithm applies a local linearization and proximity technique to make the FFT-based calculation of the analytical solutions in the frequency domain feasible, thereby significantly reducing the complexity of the algorithm. Experiments with various 3D datasets corresponding to incomplete projection data demonstrate the advantage of our proposed algorithm in terms of preserving fine details and overcoming the staircase effect. The computation cost also suggests that the proposed algorithm is applicable to and is effective for CBCT imaging. Theoretical and technical optimization should be investigated carefully in terms of both computation efficiency and high resolution of this algorithm in application-oriented research.

  15. Estimation of aortic valve leaflets from 3D CT images using local shape dictionaries and linear coding

    NASA Astrophysics Data System (ADS)

    Liang, Liang; Martin, Caitlin; Wang, Qian; Sun, Wei; Duncan, James

    2016-03-01

    Aortic valve (AV) disease is a significant cause of morbidity and mortality. The preferred treatment modality for severe AV disease is surgical resection and replacement of the native valve with either a mechanical or tissue prosthetic. In order to develop effective and long-lasting treatment methods, computational analyses, e.g., structural finite element (FE) and computational fluid dynamic simulations, are very effective for studying valve biomechanics. These computational analyses are based on mesh models of the aortic valve, which are usually constructed from 3D CT images though many hours of manual annotation, and therefore an automatic valve shape reconstruction method is desired. In this paper, we present a method for estimating the aortic valve shape from 3D cardiac CT images, which is represented by triangle meshes. We propose a pipeline for aortic valve shape estimation which includes novel algorithms for building local shape dictionaries and for building landmark detectors and curve detectors using local shape dictionaries. The method is evaluated on real patient image dataset using a leave-one-out approach and achieves an average accuracy of 0.69 mm. The work will facilitate automatic patient-specific computational modeling of the aortic valve.

  16. A user-friendly nano-CT image alignment and 3D reconstruction platform based on LabVIEW

    NASA Astrophysics Data System (ADS)

    Wang, Sheng-Hao; Zhang, Kai; Wang, Zhi-Li; Gao, Kun; Wu, Zhao; Zhu, Pei-Ping; Wu, Zi-Yu

    2015-01-01

    X-ray computed tomography at the nanometer scale (nano-CT) offers a wide range of applications in scientific and industrial areas. Here we describe a reliable, user-friendly, and fast software package based on LabVIEW that may allow us to perform all procedures after the acquisition of raw projection images in order to obtain the inner structure of the investigated sample. A suitable image alignment process to address misalignment problems among image series due to mechanical manufacturing errors, thermal expansion, and other external factors has been considered, together with a novel fast parallel beam 3D reconstruction procedure that was developed ad hoc to perform the tomographic reconstruction. We have obtained remarkably improved reconstruction results at the Beijing Synchrotron Radiation Facility after the image calibration, the fundamental role of this image alignment procedure was confirmed, which minimizes the unwanted blurs and additional streaking artifacts that are always present in reconstructed slices. Moreover, this nano-CT image alignment and its associated 3D reconstruction procedure are fully based on LabVIEW routines, significantly reducing the data post-processing cycle, thus making the activity of the users faster and easier during experimental runs.

  17. Optical CT scanner for in-air readout of gels for external radiation beam 3D dosimetry.

    PubMed

    Ramm, Daniel; Rutten, Thomas P; Shepherd, Justin; Bezak, Eva

    2012-06-21

    Optical CT scanners for a 3D readout of externally irradiated radiosensitive hydrogels currently require the use of a refractive index (RI) matching liquid bath to obtain suitable optical ray paths through the gel sample to the detector. The requirement for a RI matching liquid bath has been negated by the design of a plastic cylindrical gel container that provides parallel beam geometry through the gel sample for the majority of the projection. The design method can be used for various hydrogels. Preliminary test results for the prototype laser beam scanner with ferrous xylenol-orange gel show geometric distortion of 0.2 mm maximum, spatial resolution limited to beam spot size of about 0.4 mm and 0.8% noise (1 SD) for a uniform irradiation. Reconstruction of a star pattern irradiated through the cylinder walls demonstrates the suitability for external beam applications. The extremely simple and cost-effective construction of this optical CT scanner, together with the simplicity of scanning gel samples without RI matching fluid increases the feasibility of using 3D gel dosimetry for clinical external beam dose verifications.

  18. Automatic Segmentation of Lung Carcinoma Using 3D Texture Features in 18-FDG PET/CT.

    PubMed

    Markel, Daniel; Caldwell, Curtis; Alasti, Hamideh; Soliman, Hany; Ung, Yee; Lee, Justin; Sun, Alexander

    2013-01-01

    Target definition is the largest source of geometric uncertainty in radiation therapy. This is partly due to a lack of contrast between tumor and healthy soft tissue for computed tomography (CT) and due to blurriness, lower spatial resolution, and lack of a truly quantitative unit for positron emission tomography (PET). First-, second-, and higher-order statistics, Tamura, and structural features were characterized for PET and CT images of lung carcinoma and organs of the thorax. A combined decision tree (DT) with K-nearest neighbours (KNN) classifiers as nodes containing combinations of 3 features were trained and used for segmentation of the gross tumor volume. This approach was validated for 31 patients from two separate institutions and scanners. The results were compared with thresholding approaches, the fuzzy clustering method, the 3-level fuzzy locally adaptive Bayesian algorithm, the multivalued level set algorithm, and a single KNN using Hounsfield units and standard uptake value. The results showed the DTKNN classifier had the highest sensitivity of 73.9%, second highest average Dice coefficient of 0.607, and a specificity of 99.2% for classifying voxels when using a probabilistic ground truth provided by simultaneous truth and performance level estimation using contours drawn by 3 trained physicians.

  19. Automatic Segmentation of Lung Carcinoma Using 3D Texture Features in 18-FDG PET/CT

    PubMed Central

    Markel, Daniel; Caldwell, Curtis; Alasti, Hamideh; Soliman, Hany; Ung, Yee; Lee, Justin; Sun, Alexander

    2013-01-01

    Target definition is the largest source of geometric uncertainty in radiation therapy. This is partly due to a lack of contrast between tumor and healthy soft tissue for computed tomography (CT) and due to blurriness, lower spatial resolution, and lack of a truly quantitative unit for positron emission tomography (PET). First-, second-, and higher-order statistics, Tamura, and structural features were characterized for PET and CT images of lung carcinoma and organs of the thorax. A combined decision tree (DT) with K-nearest neighbours (KNN) classifiers as nodes containing combinations of 3 features were trained and used for segmentation of the gross tumor volume. This approach was validated for 31 patients from two separate institutions and scanners. The results were compared with thresholding approaches, the fuzzy clustering method, the 3-level fuzzy locally adaptive Bayesian algorithm, the multivalued level set algorithm, and a single KNN using Hounsfield units and standard uptake value. The results showed the DTKNN classifier had the highest sensitivity of 73.9%, second highest average Dice coefficient of 0.607, and a specificity of 99.2% for classifying voxels when using a probabilistic ground truth provided by simultaneous truth and performance level estimation using contours drawn by 3 trained physicians. PMID:23533750

  20. Remote-rendered 3D CT angiography (3DCTA) as an intraoperative aid in cerebrovascular neurosurgery.

    PubMed

    Wilkinson, E P; Shahidi, R; Wang, B; Martin, D P; Adler, J R; Steinberg, G K

    1999-01-01

    To assess the viability and utility of network-based rendering in the treatment of patients with cerebral aneurysms, we implemented an intraoperative rendering system and protocol using both three-dimensional CT angiography (3DCTA) and perspective volume rendering (PVR). A Silicon Graphics InfiniteReality engine was connected via a Fast Ethernet network to a workstation in the neurosurgical operating room. A protocol was developed to isolate bone and vessels using an appropriate transfer function. Three-dimensional CT angiogram images were volume rendered and transmitted to the workstation using a bandwidth-conserving remote rendering system, and were rotated, cut using clipping planes, and viewed using normal and perspective views. Twelve patients with intracranial aneurysms were examined at surgery using this system. Rendering performance at optimal operating bandwidths (50-60 Mb/s) was excellent, with regeneration of a high-resolution image in less than 1 s. Network performance varied in two cases, slowing image regeneration. Surgeons found the images to be useful as an adjunct to conventional imaging in understanding the morphology of complex aneurysms and their relationship to the skull base. Intraoperative volume rendering using 3DCTA is achievable over a network, can reduce hardware costs by amortizing hardware among multiple users, and provides useful imaging information during the surgical treatment of cerebral aneurysms. Future operating suites may incorporate network-transmitted three-dimensional images as additional sources of imaging information. Copyright 1999 Wiley-Liss, Inc.

  1. Development of the 3D volumetric micro-CT scanner for preclinical animals

    NASA Astrophysics Data System (ADS)

    Kim, Kyong-Woo; Kim, Kyu-Gyeom; Kim, Jae-Hee; Min, Jong-Hwan; Lee, Hee-Sin; Lee, Joonwhoan

    2011-06-01

    A high resolution micro computed tomography (micro-CT) system for live small animal imaging has been developed. The system consists of an x-ray source with micro focus spot and high brightness, rotating gantry with a x-ray tube and flat panel detector pair and a stationary and a horizontally positioned small animal bed to achieve a conebeam mode scan. The system is optimized for in vivo small animal imaging and the capability of administering respiratory anesthesia during scanning. The Feldkamp algorithm was adopted in image reconstruction with graphic processing unit (GPU). We evaluated the spatial resolution, image contrast, and uniformity of system using phantom. As the result, the spatial resolution of the system was the 56lp/mm at 10% of the MTF curve, and the radiation dose to the sample was 98mGy. The minimal resolving contrast was found to be less than 46 CT numbers on low-contrast phantom. We present the image test results of the bone and lung, and heart of the live mice. [Figure not available: see fulltext.

  2. Geodesic Distance Algorithm for Extracting the Ascending Aorta from 3D CT Images

    PubMed Central

    Jang, Yeonggul; Jung, Ho Yub; Hong, Youngtaek; Cho, Iksung; Shim, Hackjoon; Chang, Hyuk-Jae

    2016-01-01

    This paper presents a method for the automatic 3D segmentation of the ascending aorta from coronary computed tomography angiography (CCTA). The segmentation is performed in three steps. First, the initial seed points are selected by minimizing a newly proposed energy function across the Hough circles. Second, the ascending aorta is segmented by geodesic distance transformation. Third, the seed points are effectively transferred through the next axial slice by a novel transfer function. Experiments are performed using a database composed of 10 patients' CCTA images. For the experiment, the ground truths are annotated manually on the axial image slices by a medical expert. A comparative evaluation with state-of-the-art commercial aorta segmentation algorithms shows that our approach is computationally more efficient and accurate under the DSC (Dice Similarity Coefficient) measurements. PMID:26904151

  3. Practical alignment method for X-ray spectral measurement in micro-CT system based on 3D printing technology

    PubMed Central

    Ren, Liqiang; Wu, Di; Li, Yuhua; Zheng, Bin; Chen, Yong; Yang, Kai; Liu, Hong

    2016-01-01

    This study presents a practical alignment method for X-ray spectral measurement in a rotating gantry based micro-computed tomography (micro-CT) system using three-dimensional (3D) printing technology. In order to facilitate the spectrometer placement inside the gantry, supporting structures including a cover and a stand were dedicatedly designed and printed using a 3D printer. According to the relative position between the spectrometer and the stand, the upright projection of the spectrometer collimator onto the stand was determined and then marked by a tungsten pinhole. Thus, a visible alignment indicator of the X-ray central beam and the spectrometer collimator represented by the pinhole was established in the micro-CT live mode. Then, a rough alignment could be achieved through repeatedly adjusting and imaging the stand until the pinhole was located at the center of the acquired projection image. With the spectrometer being positioned back onto the stand, the precise alignment was completed by slightly translating the spectrometer-stand assembly around the rough location, until finding a “sweet spot” with the highest photon rate and proper distribution of the X-ray photons in the resultant spectrum. The spectra were acquired under precise alignment and misalignment of approximately 0.2, 0.5, and 1.0mm away from the precise alignment position, and then were compared in qualitative and quantitative analyses. Qualitative analysis results show that, with slight misalignment, the photon rate is reduced from 1302 to 1098, 1031, and 416 photons/second (p/s), respectively, and the characteristic peaks in the acquired spectra are gradually deteriorated. Quantitative analysis indicates that the energy resolutions for characteristic peak of Kα1 were calculated as 1.56% for precise alignment, while were 1.84% and 2.40% for slight misalignment of 0.2mm and 0.5mm. The mean energies were reduced from 43.93keV under precise alignment condition to 40.97, 39.63 and 37.78ke

  4. Practical alignment method for X-ray spectral measurement in micro-CT system based on 3D printing technology.

    PubMed

    Ren, Liqiang; Wu, Di; Li, Yuhua; Zheng, Bin; Chen, Yong; Yang, Kai; Liu, Hong

    2016-06-01

    This study presents a practical alignment method for X-ray spectral measurement in a rotating gantry based micro-computed tomography (micro-CT) system using three-dimensional (3D) printing technology. In order to facilitate the spectrometer placement inside the gantry, supporting structures including a cover and a stand were dedicatedly designed and printed using a 3D printer. According to the relative position between the spectrometer and the stand, the upright projection of the spectrometer collimator onto the stand was determined and then marked by a tungsten pinhole. Thus, a visible alignment indicator of the X-ray central beam and the spectrometer collimator represented by the pinhole was established in the micro-CT live mode. Then, a rough alignment could be achieved through repeatedly adjusting and imaging the stand until the pinhole was located at the center of the acquired projection image. With the spectrometer being positioned back onto the stand, the precise alignment was completed by slightly translating the spectrometer-stand assembly around the rough location, until finding a "sweet spot" with the highest photon rate and proper distribution of the X-ray photons in the resultant spectrum. The spectra were acquired under precise alignment and misalignment of approximately 0.2, 0.5, and 1.0mm away from the precise alignment position, and then were compared in qualitative and quantitative analyses. Qualitative analysis results show that, with slight misalignment, the photon rate is reduced from 1302 to 1098, 1031, and 416 photons/second (p/s), respectively, and the characteristic peaks in the acquired spectra are gradually deteriorated. Quantitative analysis indicates that the energy resolutions for characteristic peak of Kα1 were calculated as 1.56% for precise alignment, while were 1.84% and 2.40% for slight misalignment of 0.2mm and 0.5mm. The mean energies were reduced from 43.93keV under precise alignment condition to 40.97, 39.63 and 37.78keV when

  5. Assessment of angiogenesis in osseointegration of a silica-collagen biomaterial using 3D-nano-CT.

    PubMed

    Alt, Volker; Kögelmaier, Daniela Vera; Lips, Katrin S; Witt, Vera; Pacholke, Sabine; Heiss, Christian; Kampschulte, Marian; Heinemann, Sascha; Hanke, Thomas; Thormann, Ulrich; Schnettler, Reinhard; Langheinrich, Alexander C

    2011-10-01

    Bony integration of biomaterials is a complex process in which angiogenesis plays a crucial role. We evaluated micro- and nano-CT imaging to demonstrate and quantify neovascularization in bony integration of a biomaterial and to give an image based estimation for the needed resolution for imaging angiogenesis in an animal model of femora defect healing. In 8 rats 5mm full-size defects were created at the left femur that was filled with silica-collagen bone substitute material and internally fixed with plate osteosynthesis. After 6 weeks the femora were infused in situ with Microfil, harvested and scanned for micro-CT (9 μm)(3) and nano-CT (3 μm)(3) imaging. Using those 3D images, the newly formed blood vessels in the area of the biomaterial were assessed and the total vascular volume fraction, the volume of the bone substitute material and the volume of the bone defect were quantitatively characterized. Results were complemented by histology. Differences were statistically assessed using (ANOVA). High-resolution nano-CT demonstrated new blood vessel formation surrounding the biomaterial in all animals at capillary level. Immunohistochemistry confirmed the newly formed blood vessels surrounding the bone substitute material. The mean vascular volume fraction (VVF) around the implant was calculated to be 3.01 ± 0.4%. The VVF was in