Virtual Colonography Research Articles

Colorectal cancer screening with virtual colonography

Since 2003, adecline in the age-standardized incidence rates of colorectal cancer (CRC) has been observed in Germany. Nonetheless, one in eight cancer cases still affects the colon or rectum. The prognosis has improved, with the relative 5‑year survival rate for CRC being approximately 65%. This positive trend is probably aresult of preventive measures introduced over the last 20years. This could be further improved, however, as CRC can not only be detected early but in almost all cases also prevented through the identification of benign precursors. Less than half of all eligible individuals participate in screening via colonoscopy. This implies that further, possibly even imaging, screening test methods should be explored and offered. Studies have reported that virtual colonography techniques have acomparable accuracy to endoscopy of about 90% for polyp sizes larger than 5 mm. The data for computed tomography (CT) is more extensive than for magnetic resonance imaging (MRI). Significant challenges are posed however by the fact that in Germany CT colonography (CTC) is not considered aviable screening option due to radiation protection concerns, and MRI screening is not an established screening method. Radiologists should be familiar with classification using the CT Colonography Reporting and Data System (C-RADS), which uses criteria such as CT density, morphology, size, and location for classification. C‑RADS classification follows the categories: C0 (inadequate study), C1 (normal), C2a (indeterminate), C2b (benign), C3 (suspicious), and C4 (malignant), as well as extracolonic categories E1/2 (no clinically significant findings), E3 (likely insignificant findings), and E4 (likely significant findings).

Immersive Virtual Colonography Viewer for Colon Growths Diagnosis: Design and Think-Aloud Study

Desktop-based virtual colonoscopy is a proven and accurate process for identifying colon abnormalities. However, it is time-consuming. Faster, immersive interfaces for virtual colonoscopy are still incipient and need to be better understood. This article introduces a novel design that leverages VR paradigm components to enhance the efficiency and effectiveness of immersive analysis. Our approach contributes a novel tool highlighting unseen areas within the colon via eye-tracking, a flexible navigation approach, and a distinct interface for displaying scans blended with the reconstructed colon surface. The path to evaluating and validating such a tool for clinical settings is arduous. This article contributes a formative evaluation using think-aloud sessions with radiology experts and students. Questions related to colon coverage, diagnostic accuracy, and time to complete are analyzed with different user profiles. Although not aimed at quantitatively measuring performance, the experiment provides lessons learned to guide other researchers in the field.

Comprehensive study between conventional colonoscopy and virtual CT colonography in assessment of colonic disorders

Comprehensive study between conventional colonoscopy and virtual CT colonography in assessment of colonic disorders

WEO Newsletter.

WEO Newsletter.

It’s All About the Prep: Improving Colonoscopy Bowel Preparation through Patient Instructions

Colonoscopy is the most effective modality to detect and prevent colorectal cancer. The quality of bowel preparation is an important quality indicator for colonoscopy. An adequate bowel preparation requires the patient’s compliance with the preparation instructions. Currently, patients receive a copy of the instructions including the phone number of the on-call GI fellow who answers calls after hours. We aim to improve patient education and compliance with bowel preparation, as well as to educate the GI fellows on commonly used preparations and to provide standardized answers to questions frequently asked by patients. We hope to improve the overall quality of bowel preparation of our patients undergoing colonoscopy. We documented all of the patient phone calls received by the on-call GI fellows for 3 months including the questions asked by the patients, answers provided by the fellows and the quality of the preparation. We then designed a "Frequently Asked Questions and Answers" page based on the questions received to add to the bowel preparation instructions distributed to the patients. We also designed a short course for the GI fellows to review and discuss bowel preparations. We plan to document patient phone calls after the above interventions to determine if the frequency or the quality of phone calls have changed, as well as the quality of the bowel preparation. We are using data from GIQuIC to measure the overall quality of bowel preparation before and after the intervention. A total of 47 phone calls by 43 patients were received from October 10 to December 20, 2018. Out of the 47 phone calls, 38 (81%) of them can be categorized into one of the following 3 groups: no bowel movements after taking bowel preparation (18 calls), frequent bowel movements hoping to not have to complete the preparation (14 calls), or nausea/vomiting after taking the preparation (6 calls). Out of the 47 phone calls, 22 (47%) of them occurred between the hours of 10pm and 6am. After the phone calls, 9 (21%) patients cancelled their colonoscopy appointment, and 2 patients (4%) underwent scheduled virtual colonography. Out of the 32 patients (74%) who underwent their scheduled colonoscopy, the quality of their preparation was reported as excellent to good for 27 patients (84%), adequate for 1 patient (3%), fair for 2 patients (6%), and poor for 2 patients (6%). Based on GIQuIC data, 723 out 816 (88.6%) reported colonoscopies in our institution had adequate bowel preparation from October to December 2018. Patients often have similar questions regarding their bowel preparation. By providing easily accessible answers to these frequently asked questions, we hope to improve compliance and ultimately improve the overall quality of bowel preparation for scheduled colonoscopies.

Extending medical interfaces towards virtual reality and augmented reality

Introduction: The growing interest of Augmented Reality (AR) together with the renaissance of Virtual Reality (VR) opened new possibilities to redesign how professionals interact with medical images. Several medical specialties already rely on 2D and 3D image data for diagnosis, surgical planning, surgical navigation, medical education and patient-clinician communication. However, the vast majority of conventional medical interfaces and interaction techniques continue unchanged, while the most innovative solutions have not yet untapped the full potential of VR and AR because extending conventional workstations to accommodate VR and AR interaction paradigms is not free of challenges. Notably, VR and AR-based workstations, besides having to render complex anatomical data in interactive frame rates, must also promote proper anatomical insight, boost visual memory through seamless visual collaboration between professionals, unrestrained interaction from being seated at a desk (e.g., using mouse and keyboard) to adopt non-stationary postures and freely walk within a work space, and must support a fluid exchange of image data and 3D models as this foments interesting discussions to solve clinical cases. Moreover, VR and AR-based workstations should likewise be designed according to good human-computer interaction principles since it is well known that medical professionals can be resistant to changes in their workflow. To meet these challenges, we present several case studies that serve as proofs of concept represented as VR or AR prototypes, which were tested by professionals of different medical specialities. Case studies: We have identified specific areas where VR and AR paradigms can make a difference on how healthcare professionals visualize, manipulate and read 2D and 3D medical image data. The most obvious is medical education, where we are currently exploring implant planning using mobile AR and a tablet to train dentistry students. Another specific area is radiodiagnostics, where we evaluated the positive impact of VR, namely, on how radiologists analyze images when immersed inside a virtual reading room [1], and on how radiologists may perform immersive virtual colonography. Also in surgical navigation, AR head-mounted displays carry the promise to assist surgeons performing laparoscopic surgery, in particular, how optical see-through head-mounted displays can assist the surgeon’s eye-hand coordination and to clarify the location of anatomical landmarks displayed on the video stream. Finally, we explore how AR, using multiple projection surfaces, can assist users to perform rehabilitation exercises by themselves under the offline supervision of a physiotherapist [2].

Clinical Imaging Technology and the Diagnosis in Patient-centered Interdisciplinary Care.

Clinical imaging examinations and the diagnosis of their findings play an important role in patientcentered interdisciplinary care. Clinical imaging tests, such as X-ray, computed tomography (CT), magnetic resonance imaging (MRI) and nuclear medicine scans, are performed both in the initial diagnosis to identify the disease and at follow-up with the radiology team. Imaging technology is advancing day by day, both the hardware and software. CT and MRI are useful for confirming the size and location of lesions, providing what is known as morphologic images. CT can perform whole-body imaging very quickly, and the huge data are reconstructed in many ways with advanced computer systems. Three-dimensional CT, such as virtual colonography and bronchography, isuseful for planning the approach before surgery or endoscopic study. MRI isuseful for detecting acute cerebral infarction and evaluating brain perfusion or brain metabolites using MR spectroscopy. Fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT is a molecular imaging modality mainly used in oncology for the initial diagnosis, staging and detection of recurrence or metastasis after treatment as well as the evaluation of the treatment response. The focus of this paper was to elucidate the typesand use of clinical imaging technologies, with a focus on CT, MRI and FDG-PET. J. Med.I nvest. 66:31-34, February, 2019.

Virtual CT Colonography: Technique and findings: Single Institute experience.

Colorectal cancer is the second leading cause of death due to malignancy in industrialized counties. It is argued that most large bowel malignancies arise from preexisting adenormas. Computed tomographic (CT) colonography is a noninvasive, rapidly evolving technique that has been shown in some studies to be comparable with conventional colonoscopy for the screening of colorectal cancer. However, widespread colorectal screening and preventive efforts aimed at detecting disease in this early stage are opposed by several practical obstacles, including limited resources, and poor patient acceptance and therefore poor compliance (1-2). Patients and methods

Virtual CT Colonography Versus Lower Endoscopy in Detection of Colorectal Lesions.

Colorectal cancer is the third most common cancer and the second leading cause of cancer-related death in Western countries. As with other malignancies, screening and early detection is fundamental for successful management of colorectal cancer. Computed tomographic (CT) colonography is a noninvasive, rapidly evolving technique that has been shown in some studies to be comparable with conventional colonoscopy for the screening of colorectal cancer. CT colonography is being increasingly applied as a routine screening method for the detection of colorectal cancer in last few years as it is more convenient and less invasive than colonoscopy. In addition, it has an upper hand in diagnosis of small lesions less than 10mm (Choi, et al., 2011). Patients and methods:This prospective double blind comparative study will be conducted on 23 patients with colorectal symptoms and signs as altered bowel habits, bleeding per rectum, abdominal pain, weight loss, unexplained fatigue and loss of appetite.An informed written consent was obtained from all patients and approval of the faculty research ethics committee was obtained. Results: Total of 108 colonic lesions were analyzed in 23 patient; Seven colonic masses were diagnosed in 6 patients, 41 polyps in 8 patients and 60 diverticulae in 5 patients. Six patients had incomplete colonoscopy. Of them, 2 patients had a large polypoidal mass that prevents further colonoscopic introduction. Using CT colonography we were able to evaluate those polypoidal masses. Moreover, we could complete the examination and evaluation of the proximal colon and one of them had a polypoidal sigmoid colon mass and showed another proximal annular mass. Four patients presented with colonic obstruction and good preparation to the proximal parts of the colon failed, So completing the colonoscopy was difficult. After undergoing CT colonography, 2 patients were normal and 2 patients had annular masses causing proximal obstruction and marked distension. ConclusionCT Colonography (Virtual Colonoscopy) is a reliable tool and more sensitive for detecting colonic mass lesions larger than 5 mm, polyps larger than 5 mm, strictures and diverticulosis. CTC is of value in evaluating the colonic segment lying proximal to colonic cancers including those with occlusive growths or strictures. Contrast-enhanced CTC is also useful in identifying extra-colonic findings.Virtual Colonoscopy is a good screening tools for malignant or premalignant lesions in patients presented with colorectal symptoms.

Sigmoid Perforation during CT Colonography in a Patient with an Inguinal Hernia and Concomitant Finding of a Right-Sided Colon Cancer

The use of computed tomography colonography or virtual colonography (VC) is gaining acceptance as a screening modality for colon cancer. A comprehensive understanding of VC complications is limited. We report a case of colon perforation in a patient where a colon cancer was diagnosed using VC colonography with manual insufflation. A 79-year-old patient underwent a VC after a failed screening optical colonoscopy (OC). The initial radiological findings included a large amount of mesoperitoneum and retroperitoneal air near the proximal sigmoid and a left inguinal hernia containing the distal sigmoid colon suggesting a colonic perforation caused by colonic obstruction. Subsequent radiological interpretation revealed a 1.5 cm lesion in the posterior cecum. The patient underwent repair of the hernia, sigmoid resection for sigmoid perforation, followed by intra-operative colonoscopy (which confirmed the radiographic findings of a cecal lesion) and right colectomy. Pathologic examination confirmed the T3, N0, MX adenocarcinoma.

Endoscopic training in gastroenterology fellowship: adherence to core curriculum guidelines.

The Gastroenterology Core Curriculum and American Society of Gastrointestinal Endoscopy provide guidelines for endoscopic training. Program adherence to these recommendations is unclear. This study aims to assess endoscopic training experience during fellowship. Questionnaire study. The questionnaire was circulated to US fellowship programs, with the assistance of the American Gastroenterological Association. Graduating third-year fellows. Seventy-three fellows returned the questionnaire. Nearly all fellows met the required numbers for esophagoduodenoscopy (98%) and colonoscopy (100%), with fewer meeting requirements for PEG (73%) and non-variceal hemorrhage (75%). The majority of fellows did not meet minimum numbers for variceal banding (40%), esophageal dilation (43%), capsule endoscopy (42%). Fellows rated training in cognitive aspects of endoscopy as 3.86 [1 (inadequate), 5 (excellent)] and reported greatest emphasis on interpreting endoscopic findings and least on virtual colonography. Quality indicators of endoscopy received little emphasis (rating of 3.04; p = 0.00001), with adenoma detection rate being least emphasized. Fifty-six percent of fellows reported having routine endoscopy conferences. Half of the programs have endoscopic simulators, with 15% of fellows being required to use simulation. Following direct hands-on experience, fellows rated external endoscopy courses (64%) as the next most useful experience. Many fellows do not meet required numbers for several endoscopic procedures, and quality indicators receive little emphasis during training. Most programs do not provide simulation training or hold regular endoscopy conferences. Fellowship programs should perform internal audits and make feasible adjustments. Furthermore, it may be time for professional societies to revisit training guidelines.

Colon PillCam: why not just take a pill?

This review article deals with the clinical value of capsule endoscopy for visualization of the colon. Since its introduction in 2006, the colon capsule endoscopy underwent major technological improvements. The improved performance of colon capsule endoscopy is reviewed based on three multicenter prospective studies. Screening patients for colonic adenomatous polyps is reasonable in patients who are unwilling to undergo conventional colonoscopy. Another prospective study proved that colon capsule endoscopy is effective in incomplete colonoscopy. Colon capsule endoscopy was shown to be superior to virtual colonography in the evaluation of patients with incomplete colonoscopy. Further improvements are expected in colon capsule endoscopy.

Staging of colorectal cancer using contrast-enhanced multidetector computed tomographic colonography.

Preoperative staging is essential for the optimal treatment and surgical planning of colorectal cancers. This study was aimed to evaluate the accuracy of colorectal cancer staging done using contrast-enhanced multidetector computed tomographic colonography (CEMDCTC). We recruited 25 patients with 28 proven colorectal cancers. A 16-slice multidetector computed tomography scanner was used to generate two-dimensional multiplanar reformatted sagittal, coronal and oblique coronal images, and three-dimensional virtual colonography (endoluminal) images. Axial and reformatted views were analysed, and TNM staging was done. Patients underwent surgery and conventional colonoscopy, and surgical histopathological correlation was obtained. The diagnostic accuracies for TNM colorectal cancer staging were 92.3% for T staging, 42.3% for N staging and 96.1% for M staging using CEMDCTC. There was excellent positive correlation for T staging between CEMDCTC and both surgery (κ-value = 0.686) and histopathology (κ-value = 0.838) (p < 0.0001), and moderate positive correlation for N staging between CEMDCTC and surgery (κ-value = 0.424; p < 0.0001). The correlation between CEMDCTC and histopathology for N staging was poor (κ-value = 0.186; p < 0.05); the negative predictive value was 100% for lymph node detection. Moderate positive correlation was seen for M staging between CEMDCTC and both surgery (κ-value = 0.462) and histopathology (κ-value = 0.649). No false negatives were identified in any of the M0 cases. CEMDCTC correlated well with pathologic T and M stages, but poorly with pathologic N stage. It is an extremely accurate tool for T staging, but cannot reliably distinguish between malignant lymph nodes and enlarged reactive lymph nodes.

In vivo MRI virtual colonography in a mouse model of colon cancer.

We have developed a reliable noninvasive method for monitoring colonic tumors and mucosal inflammation in a mouse model of colon cancer using magnetic resonance colonography (MRC). After a mild cleansing enema, the colon is filled with Fluorinert, a perfluorinated liquid that does not produce a proton MR signal. The mouse is placed in a dedicated volume MR receiver coil, and high-resolution images are acquired in three planes. The Fluorinert enema distends the mouse colon, creating an artifact-free black homogeneous background, allowing clear delineation of the inflamed colonic wall and visualization of luminal tumors in various stages of development. A gadolinium-based contrast agent can be administered i.v. to the animal to detect mural inflammation or tumor vascularity. This technique is useful for serial monitoring of the effects of preventive or therapeutic strategies on tumor development without killing the animal or requiring invasive endoscopies. The animal preparation and imaging can be completed in ∼1.5 h.

Colonoscopia óptica y colonoscopia virtual. El papel de cada una hoy

The importance of optical or conventional colonoscopy in diagnosing colon disease is undisputed. In this context, optical colonoscopy is the gold standard against which other techniques must be validated. Apart from enabling direct inspection of the colonic mucosa, optical colonoscopy enables biopsies and techniques to treat and prevent colorectal cancer. Virtual colonoscopy or CT colonography has been validated in multicenter studies; virtual colonoscopy is as sensitive as optical colonoscopy for the detection of polyps and colon cancer. It is currently the only valid alternative to optical colonoscopy. Its role in patients with medium or high risk of colon cancer is in the process of being defined as multidisciplinary teams gain experience. This article aims to discuss the usefulness of virtual colonoscopy in different clinical situations, emphasizing the situations in which there is enough scientific evidence, and to discuss the controversies surrounding its possible use for population-based screening.

Application of Pseudo-enhancement Correction to Virtual Monochromatic CT Colonography.

In CT colonography, orally administered positive-contrast fecal-tagging agents are used for differentiating residual fluid and feces from true lesions. However, the presence of high-density tagging agent in the colon can introduce erroneous artifacts, such as local pseudo-enhancement and beam-hardening, on the reconstructed CT images, thereby complicating reliable detection of soft-tissue lesions. In dual-energy CT colonography, such image artifacts can be reduced by the calculation of virtual monochromatic CT images, which provide more accurate quantitative attenuation measurements than conventional single-energy CT colonography. In practice, however, virtual monochromatic images may still contain some pseudo-enhancement artifacts, and efforts to minimize radiation dose may enhance such artifacts. In this study, we evaluated the effect of image-based pseudo-enhancement post-correction on virtual monochromatic images in standard-dose and low-dose dual-energy CT colonography. The mean CT values of the virtual monochromatic standard-dose CT images of 51 polyps and those of the virtual monochromatic low-dose CT images of 20 polyps were measured without and with the pseudo-enhancement correction. Statistically significant differences were observed between uncorrected and pseudo-enhancement-corrected images of polyps covered by fecal tagging in standard-dose CT (p < 0.001) and in low-dose CT (p < 0.05). The results indicate that image-based pseudo-enhancement post-correction can be useful for optimizing the performance of image-processing applications in virtual monochromatic CT colonography.

MD1 - Comparing Virtual Colonography with Conventional Colonoscopy for Colorectal Cancer Screening: What are the Drivers of Cost-effectiveness?

MD1 - Comparing Virtual Colonography with Conventional Colonoscopy for Colorectal Cancer Screening: What are the Drivers of Cost-effectiveness?

Impact of Inappropriate Fecal Occult Blood Testing in the Veterans Health Administration

Purpose: To reduce costs associated with and improve the process of colorectal cancer screening by identifying the number of colonoscopies which result from inappropriate fecal occult blood testing (FOBT) in the Veterans Health Administration (VHA). Methods: Inappropriate screening FOBT for fiscal year (FY) 2011 at a single VHA facility was derived using the Veterans Integrated Service Network 7 (VISN7) Corporate Data Warehouse. Inappropriate screening FOBT was defined as FOBT performed within nine years of a prior colonoscopy, four years of a CT colonography or double contrast barium enema, or 10 months of FOBT. FOBT conducted for diagnostic purposes, defined as inpatient testing or single FOBT card, was excluded. For a portion of the individuals who met criteria for inappropriate FOBT, a chart review was conducted to ensure accuracy of collection methodology. Results from the subset of cases which were chart reviewed were extrapolated to the total number of patients that met initial inclusion criteria. Results: Of 7,765 screening FOBT performed at a single VHA facility in FY2011, 1,061 were inappropriate based on our inclusion criteria. The charts were reviewed for 275 (26%) of the 1,061 inappropriate FOBT cases, of which 259 were identified as true inappropriate FOBT. The remaining 16 FOBT were deemed appropriate due to the recommendation by the endoscopist to resume screening at an interval less than 10 years due to bowel preparation quality. Of the 259 inappropriate screening FOBT, 59 were positive, leading to 47 additional follow-up procedures (either colonoscopy or virtual colonography). Colorectal cancer was not detected in any of these procedures. Extrapolating to the cohort of 7,765 screening FOBT performed in a single VHA facility in FY2011, an estimated 999 screening FOBT (13%) were inappropriate. Of these, an estimated 228 (23%) were positive and led to approximately 181 unnecessary procedures. Conclusion: FOBT for colorectal cancer screening is often overused and, if positive, exposes patients to additional tests and their associated potential risks. Several interventions may help to reduce this costly problem: improved visibility of non-VHA facility colonoscopy reports in the medical record; reminder systems which integrate all modalities of CRC screening conducted within VHA or entered by provider or staff based on non-VHA screening; and provider education regarding indications for FOBT.

Early colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Early colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Virtual colonoscopy and PET/CT for diagnosis and staging of colorectal cancer

Colo-rectal cancer is the most common malignancy of the gastrointestinal tract and is the third frequency for malignancy in humans. CT and MRI development allows an early diagnosis and a modulation of the therapeutic approach. Many papers seem to confirm the role of PET/CT and virtual colonography in the evaluation of primary lesions. The PET/CT appears mode accurate in assessing lymph node metastases. Today, new approaches such as virtual colonoscopy and PET/CT open new horizons in the diagnosis and staging of cancer of the colon and rectum.