Elizabeth G. McFarland

Managing Incidental Findings in Human Subjects Research: Analysis and Recommendations

No consensus yet exists on how to handle incidental findings (IFs) in human subjects research. Yet empirical studies document IFs in a wide range of research studies, where IFs are findings beyond the aims of the study that are of potential health or reproductive importance to the individual research participant. This paper reports recommendations of a two-year project group funded by NIH to study how to manage IFs in genetic and genomic research, as well as imaging research. We conclude that researchers have an obligation to address the possibility of discovering IFs in their protocol and communications with the IRB, and in their consent forms and communications with research participants. Researchers should establish a pathway for handling IFs and communicate that to the IRB and research participants. We recommend a pathway and categorize IFs into those that must be disclosed to research participants, those that may be disclosed, and those that should not be disclosed.

Patient Preferences for CT Colonography, Conventional Colonoscopy, and Bowel Preparation

Abstract Objectives The aim of this study was to determine patient pre-examination expectations and postexamination appraisals for CT colonography, conventional colonoscopy and bowel preparation. Methods Prospective evaluation of 120 patients at defined risk for colorectal neoplasia was performed with CT colonography followed by colonoscopy on the same day. Subjects were stratified by age and sex (67 women and 53 men) and were randomized to receive either manual air (n = 61) or CO2 (n = 59) insufflation during CT colonography. Patients’ expectations were assessed just before the two examinations, and appraisals were assessed 2 to 3 days afterward regarding pain/discomfort, embarrassment, difficulty, overall assessment, preference for future testing, and bowel preparation. Results No significant differences were found in appraisals of manual air versus CO2 insufflation techniques. For both CT colonography and colonoscopy, patients’ appraisals after the procedure were significantly more positive than prior expectations. Patients expressed more favorable appraisals of colonoscopy for pain (p Conclusions Overall appraisals were similar and positive for both CT colonography and colonoscopy, with less favorable appraisals of the bowel preparation. Most patients stated that they would prefer CT for future evaluation.

Incidental Findings in Imaging Research Evaluating Incidence, Benefit, and Burden

BACKGROUND Little information exists concerning the frequency and medical significance of incidental findings (IFs) in imaging research. METHODS Medical records of research participants undergoing a research imaging examination interpreted by a radiologist during January through March 2004 were reviewed, with 3-year clinical follow-up. An expert panel reviewed all IFs generating clinical action to determine medical benefit/burden on the basis of predefined criteria. The frequency of IFs that generated further clinical action was estimated by modality, body part, age, and sex, along with net medical benefit or burden. RESULTS Of 1426 research imaging examinations, 567 (39.8%) had at least 1 IF (1055 total). Risk of an IF increased significantly by age (odds ratio [OR], 1.5; 95% confidence interval, 1.4-1.7 per decade increase). Abdominopelvic computed tomography generated more IFs than other examinations (OR, 18.9 vs ultrasonography; 9.2% with subsequent clinical action), with computed tomography of the thorax and magnetic resonance imaging of the head next (OR, 11.9 and 5.9; 2.8% and 2.2% with action, respectively). Of the 567 examinations with an IF, 35 (6.2%) generated clinical action, resulting in clear medical benefit in 1.1% (6 of 567) and clear medical burden in 0.5% (3 of 567). Medical benefit/burden was usually unclear (26 of 567 [4.6%]). CONCLUSIONS Frequency of IFs in imaging research examinations varies significantly by imaging modality, body region, and age. Research imaging studies at high risk for generating IFs can be identified. Routine evaluation of research images by radiologists may result in identification of IFs in a high number of cases and subsequent clinical action to address them in a small but significant minority. Such clinical action can result in medical benefit to a small number of patients.

Computerized tomographic colonography: Performance evaluation in a retrospective multicenter setting

BACKGROUND & AIMS No multicenter study has been reported evaluating the performance and interobserver variability of computerized tomographic colonography. The aim of this study was to assess the accuracy of computerized tomographic colonography for detecting clinically important colorectal neoplasia (polyps >or=10 mm in diameter) in a multi-institutional study. METHODS A retrospective study was developed from 341 patients who had computerized tomographic colonography and colonoscopy among 8 medical centers. Colonoscopy and pathology reports provided the standard. A random sample of 117 patients, stratified by criterion standard, was requested. Ninety-three patients were included (47% with polyps >or=10 mm; mean age, 62 years; 56% men; 84% white; 40% reported colorectal symptoms; 74% at increased risk for colorectal cancer). Eighteen radiologists blinded to the criterion standard interpreted computerized tomography colonography examinations, each using 2 of 3 different software display platforms. RESULTS The average area under the receiver operating characteristic curve for identifying patients with at least 1 lesion >or=10 mm was 0.80 (95% lower confidence bound, 0.74). The average sensitivity and specificity were 75% (95% lower confidence bound, 68%) and 73% (95% lower confidence bound, 66%), respectively. Per-polyp sensitivity was 75%. A trend was observed for better performance with more observer experience. There was no difference in performance across software display platforms. CONCLUSIONS Computerized tomographic colonography performance compared favorably with reported performance of fecal occult blood testing, flexible sigmoidoscopy, and barium enema. A prospective study evaluating the performance of computerized tomography colonography in a screening population is indicated.

ACR Colon Cancer Committee White Paper: Status of CT Colonography 2009

PURPOSE To review the current status and rationale of the updated ACR practice guidelines for CT colonography (CTC). METHODS Clinical validation trials in both the United States and Europe are reviewed. Key technical aspects of the CTC examination are emphasized, including low-dose protocols, proper insufflation, and bowel preparation. Important issues of implementation are discussed, including training and certification, definition of the target lesion, reporting of colonic and extracolonic findings, quality metrics, reimbursement, and cost-effectiveness. RESULTS Successful validation trials in screening cohorts both in the United States with ACRIN and in Germany demonstrated sensitivity > or = 90% for patients with polyps >10 mm. Proper technique is critical, including low-dose techniques in screening cohorts, with an upper limit of the CT dose index by volume of 12.5 mGy per examination. Training new readers includes the requirement of interactive workstation training with 2-D and 3-D image display techniques. The target lesion is defined as a polyp > or = 6 mm, consistent with the American Cancer Society joint guidelines. Five quality metrics have been defined for CTC, with pilot data entered. Although the CMS national noncoverage decision in May 2009 was a disappointment, multiple third-party payers are reimbursing for screening CTC. Cost-effective modeling has shown CTC to be a dominant strategy, including in a Medicare cohort. CONCLUSION Supported by third-party payer reimbursement for screening, CTC will continue to further transition into community practice and can provide an important adjunctive examination for colorectal screening.

Revised Colorectal Screening Guidelines: Joint Effort of the American Cancer Society, U.S. Multisociety Task Force on Colorectal Cancer, and American College of Radiology

Elizabeth G. McFarland, MD Bernard Levin, MD David A. Lieberman, MD Perry J. Pickhardt, MD C. Daniel Johnson, MD Seth N. Glick, MD Durado Brooks, MD, MPH Robert A. Smith, PhD Editor’s Note: This editorial refers to the 2008 revised colorectal screening guidelines jointly published by the American Cancer Society (ACS) and the American Gastroenterology Association. The full guidelines are reprinted, with permission from the ACS, online at http://radiology.rsnajnls.org/content /full/248/3/717/DC1. Subsequent to publication in CA A Cancer Journal for Clinicians, an erratum was issued regarding the listing of authors of the original report (CA Cancer J Clin, 2008;58:160).

Spiral computed tomographic colonography: Determination of the central axis and digital unraveling of the colon

RATIONALE AND OBJECTIVES The authors developed and tested automated and semiautomated bowel-lumen tracking and colon-unraveling techniques for determining the central axis of the bowel. METHODS A computer-simulated gastrointestinal tract phantom was used to test the accuracy of an automated algorithm for central axis determination and bowel unraveling. Variations in cross-sectional features between straight and unraveled formats were compared in a canine bowel segment in vitro and a human colon in vivo by using spiral computed tomography. Three readers each performed three semiautomated evaluations. RESULTS Accuracy of the automated algorithm was confirmed by the high degree of correlation in the cross-sectional feature measurements (length error, < 1%). For the canine colon segment, accuracy of the semiautomated algorithm was confirmed by comparison with the automated tracing. For the human colon, readings were reproducible with 3.3% (+/- 1.9 standard deviation) mean variation in length. CONCLUSION An automated algorithm for central axis deterioration and unraveling the colon has been validated in a gastrointestinal tract phantom. A semiautomated algorithm has been shown to be reproducible and time-efficient.

Straightening the colon with curved cross sections: An approach to CT colonography

RATIONALE AND OBJECTIVES The purpose of this study was to straighten digitally and consistently the colon with curved cross sections and to compare the results with planar cross-section-based processing for computed tomographic (CT) colonography. MATERIALS AND METHODS In electric field-based straightening, curved cross sections are formed along electric force lines because of electric charges digitally distributed along the colon central path. Four straightening experiments were conducted on CT scans of a colonoscopy phantom. Representative images were studied for polyp detectability and feature distortion. Two further trials involved patient data to demonstrate the clinical feasibility of this method. RESULTS In colon straightening with planar sections, a polyp was counted multiple times in both phantom and patient studies where the polyps were in central path turns with substantial curvature. Furthermore, opposite the central path turns, the colon walls were undersampled with planar sections. Straightening with curved sections produced consistent mappings. Image distortion was present in straightening with curved sections, but the conspicuity of polyps was maintained. In the soft-straightening process, trilinear interpolation greatly suppressed the surface- or volume-rendering noise associated with nearest neighbor interpolation. CONCLUSION Straightening with curved sections outperforms straightening with planar sections in terms of polyp detectability. This approach eliminates the navigation difficulties of current CT colonography and may have clinical use.

Understanding the contribution of family history to colorectal cancer risk and its clinical implications: A state‐of‐the‐science review

Persons with a family history (FH) of colorectal cancer (CRC) or adenomas that are not due to known hereditary syndromes have an increased risk for CRC. An understanding of these risks, screening recommendations, and screening behaviors can inform strategies for reducing the CRC burden in these families. A comprehensive review of the literature published within the past 10 years has been performed to assess what is known about cancer risk, screening guidelines, adherence and barriers to screening, and effective interventions in persons with an FH of CRC and to identify FH tools used to identify these individuals and inform care. Existing data show that having 1 affected first‐degree relative (FDR) increases the CRC risk 2‐fold, and the risk increases with multiple affected FDRs and a younger age at diagnosis. There is variability in screening recommendations across consensus guidelines. Screening adherence is <50% and is lower in persons under the age of 50 years. A providers recommendation, multiple affected relatives, and family encouragement facilitate screening; insufficient collection of FH, low knowledge of guidelines, and poor family communication are important barriers. Effective interventions incorporate strategies for overcoming barriers, but these have not been broadly tested in clinical settings. Four strategies for reducing CRC in persons with familial risk are suggested: 1) improving the collection and utilization of the FH of cancer, 2) establishing a consensus for screening guidelines by FH, 3) enhancing provider‐patient knowledge of guidelines and communication about CRC risk, and 4) encouraging survivors to promote screening within their families and partnering with existing screening programs to expand their reach to high‐risk groups. Cancer 2016.

Colon unraveling based on electrical field: recent progress and further work

CT colonography (CTC) is a new technology, which permits endoscopic-like evaluation of the mucosal surface. Recently, an electrical field based approach was developed to unravel the colon in spiral CT image volumes, that is to digitally straighten then flatten the colon using curved cross-sections. In this paper, we report (1) an exact and computation- intensive algorithm for straightening the colon using curved cross-sections, and (2) an approximate but computationally efficient straightening algorithm. In the direct straightening algorithm, each curved cross-section of the colon is defined by electrical force lines due to charges distributed along the colon path, and constructed by directly tracing the force lines. In the fast straightening algorithm, only representative force lines are traced that originate equiangularly from the current colon path position, while other force lines are interpolated from the traced force lines. The experiments are performed with both phantom and patient data. It is demonstrated that straightening the colon with curved cross-sections facilitates visualization and analysis, has potential for use in CTC; and the speed of the interpolation based straightening algorithm is practically acceptable, which is about 40 times faster than that of the direct algorithm.