Membranous urethral length measurement on preoperative MRI to predict incontinence after radical prostatectomy: a literature review towards a proposal for measurement standardization.

OBJECTIVES: To investigate the membranous urethral length (MUL) measurement and its interobserver agreement, and propose literature-based recommendations to standardize MUL measurement for increasing interobserver agreement. MUL measurements based on prostate MRI scans, for urinary incontinence risk assessment before radical prostatectomy (RP), may influence treatment decision-making in men with localised prostate cancer. Before implementation in clinical practise, MRI-based MUL measurements need standardization to improve observer agreement. METHODS: Online libraries were searched up to August 5, 2022, on MUL measurements. Two reviewers performed article selection and critical appraisal. Papers reporting on preoperative MUL measurements and urinary continence correlation were selected. Extracted information included measuring procedures, MRI sequences, population mean/median values, and observer agreement. RESULTS: Fifty papers were included. Studies that specified the MRI sequence used T2-weighted images and used either coronal images (n = 13), sagittal images (n = 18), or both (n = 12) for MUL measurements. 'Prostatic apex' was the most common description of the proximal membranous urethra landmark and 'level/entry of the urethra into the penile bulb' was the most common description of the distal landmark. Population mean (median) MUL value range was 10.4-17.1 mm (7.3-17.3 mm), suggesting either population or measurement differences. Detailed measurement technique descriptions for reproducibility were lacking. Recommendations on MRI-based MUL measurement were formulated by using anatomical landmarks and detailed descriptions and illustrations. CONCLUSIONS: In order to improve on measurement variability, a literature-based measuring method of the MUL was proposed, supported by several illustrative case studies, in an attempt to standardize MRI-based MUL measurements for appropriate urinary incontinence risk preoperatively. CLINICAL RELEVANCE STATEMENT: Implementation of MUL measurements into clinical practise for personalized post-prostatectomy continence prediction is hampered by lack of standardization and suboptimal interobserver agreement. Our proposed standardized MUL measurement aims to facilitate standardization and to improve the interobserver agreement. KEY POINTS: • Variable approaches for membranous urethral length measurement are being used, without detailed description and with substantial differences in length of the membranous urethra, hampering standardization. • Limited interobserver agreement for membranous urethral length measurement was observed in several studies, while preoperative incontinence risk assessment necessitates high interobserver agreement. • Literature-based recommendations are proposed to standardize MRI-based membranous urethral length measurement for increasing interobserver agreement and improving preoperative incontinence risk assessment, using anatomical landmarks on sagittal T2-weighted images.

Prostate MRI for Improving Personalized Risk Prediction of Incontinence and Surgical Planning: The Role of Membranous Urethral Length Measurements and the Use of 3D Models.

Prostate MRI has an important role in prostate cancer diagnosis and treatment, including detection, the targeting of prostate biopsies, staging and guiding radiotherapy and active surveillance. However, there are other ''less well-known'' applications which are being studied and frequently used in our highly specialized medical center. In this review, we focus on two research topics that lie within the expertise of this study group: (1) anatomical parameters predicting the risk of urinary incontinence after radical prostatectomy, allowing more personalized shared decision-making, with special emphasis on the membranous urethral length (MUL); (2) the use of three-dimensional models to help the surgical planning. These models may be used for training, patient counselling, personalized estimation of nerve sparing and extracapsular extension and may help to achieve negative surgical margins and undetectable postoperative PSA values.

A standardized method to measure the membranous urethral length (MUL) on MRI of the prostate with high inter- and intra-observer agreement.

OBJECTIVES: The membranous urethral length (MUL), defined as the length between the apex and penile base as measured on preoperative prostate magnetic resonance imaging (MRI), is an important predictor for urinary incontinence after radical prostatectomy. Literature on inter- and intra - observer agreement of MUL measurement is limited. We studied the inter- and intra-observer agreement between radiologists using a well-defined method to measure the MUL on the prostate MRI. METHODS: Prostate cancer patients underwent a preoperative MRI and robot-assisted radical prostatectomy (RARP) at one high-volume RARP center. MUL measurement was based on well-defined landmarks on sagittal T2-weighted (anatomical) images. Three radiologists independently performed MUL measurements retrospectively in 106 patients blinded to themselves, to each other, and to clinical outcomes. The inter- and intra-observer agreement of MUL measurement between the radiologists were calculated, expressed as intra-class correlation coefficient (ICC). RESULTS: The initial inter-observer agreement was ICC 0.63; 95% confidence interval (CI) 0.28-0.81. Radiologist 3 measured the MUL mean 3.9 mm (SD 3.3) longer than the other readers, interpreting the caudal point of the MUL (penile base) differently. After discussion on the correct anatomical definition, radiologist 3 re-assessed all scans, which resulted in a high inter-observer agreement (ICC 0.84; 95% CI 0.66-0.91). After a subsequent reading by radiologists 1 and 2, the intra-observer agreements were ICC 0.93; 95% CI 0.89-0.96, and ICC 0.98; 95% CI 0.97-0.98, respectively. Limitation is the monocenter design. CONCLUSIONS: The MUL can be measured reliably with high agreement among radiologists. KEY POINTS: • After discussion on the correct anatomical definition, the inter- and intra - observer agreements of membranous urethral length (MUL) measurement on magnetic resonance imaging (MRI) were high. • A reproducible method to measure the MUL can improve the clinical usefulness of prediction models for urinary continence after RARP which may benefit patient counselling.

Value of Different Magnetic Resonance Imaging-based Measurements of Anatomical Structures on Preoperative Prostate Imaging in Predicting Urinary Continence After Radical Prostatectomy in Men with Prostate Cancer: A Systematic Review and Meta-analysis.

CONTEXT: Measurements of anatomical structures on preoperative prostate magnetic resonance imaging (MRI) are used in risk models for treatment decisions to predict urinary continence (UC) following radical prostatectomy (RP). However, the association between these parameters and UC is unclear. OBJECTIVE: To systematically summarize the literature on prognostic preoperative prostate MRI measurements of (peri)prostatic structures in relation to time to recovery of postoperative UC in men with prostate cancer. EVIDENCE ACQUISITION: Online libraries were searched up to August 27, 2021. Article selection and critical appraisal were performed by two reviewers. All papers reporting on preoperative MRI measurements with UC correlation in univariable or multivariable analyses were included. EVIDENCE SYNTHESIS: In the 50 studies included (mostly retrospective), 57 MRI parameters were evaluated. The pooled analyses showed that greater membranous urethra length (MUL) was prognostic for regaining UC at 1 mo (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.10-1.21), 3 mo (OR 1.23, 95% CI 1.16-1.31), 6 mo (OR 1.16, 95% CI 1.08-1.25), and 12 mo (OR 1.19, 95% CI 1.10-1.29). Several other anatomical structures showed at least in one study a significant correlation with later return to UC: four prostate-related parameters (greater depth, apical protrusion, larger intravesical protrusion, small dorsal vascular complex), five urethra-related parameters (thicker wall, severe fibrosis, smaller volume, larger preoperative angle between the prostate axis and membranous urethra, shorter minimal residual MUL), and six musculoskeletal-related parameters (lower perfusion ratio, thinner levator ani muscle, larger inner or outer levator distance, shorter pelvic diaphragm length, and larger midpelvic area). CONCLUSIONS: Greater MUL as measured on preoperative MRI was an independent prognostic factor for return to UC within 1 mo after RP and remained prognostic at 12 mo. Other anatomical structures may potentially be predictive, but these would need to be substantiated in prospective trials before being adopted in postoperative UC risk models for treatment decisions in men with prostate cancer. PATIENT SUMMARY: We summarized study data on the relation between measurements of anatomical structures on preoperative magnetic resonance imaging scans and urinary continence after removal of the prostate. Greater length of one part of the urethra (membranous urethra) is associated with faster return to continence. Other anatomical structures have potential for predicting postoperative continence, but need further investigation.

Imaging alternatives to colonoscopy: CT colonography and colon capsule. European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline - Update 2020.

MAIN RECOMMENDATIONS: 1. ESGE/ESGAR recommend computed tomographic colonography (CTC) as the radiological examination of choice for the diagnosis of colorectal neoplasia. Strong recommendation, high quality evidence. ESGE/ESGAR do not recommend barium enema in this setting. Strong recommendation, high quality evidence.2. ESGE/ESGAR recommend CTC, preferably the same or next day, if colonoscopy is incomplete. The timing depends on an interdisciplinary decision including endoscopic and radiological factors. Strong recommendation, low quality evidence. ESGE/ESGAR suggests that, in centers with expertise in and availability of colon capsule endoscopy (CCE), CCE preferably the same or the next day may be considered if colonoscopy is incomplete. Weak recommendation, low quality evidence.3. When colonoscopy is contraindicated or not possible, ESGE/ESGAR recommend CTC as an acceptable and equally sensitive alternative for patients with alarm symptoms. Strong recommendation, high quality evidence. Because of lack of direct evidence, ESGE/ESGAR do not recommend CCE in this situation. Very low quality evidence. ESGE/ESGAR recommend CTC as an acceptable alternative to colonoscopy for patients with non-alarm symptoms. Strong recommendation, high quality evidence. In centers with availability, ESGE/ESGAR suggests that CCE may be considered in patients with non-alarm symptoms. Weak recommendation, low quality evidence.4. Where there is no organized fecal immunochemical test (FIT)-based population colorectal screening program, ESGE/ESGAR recommend CTC as an option for colorectal cancer screening, providing the screenee is adequately informed about test characteristics, benefits, and risks, and depending on local service- and patient-related factors. Strong recommendation, high quality evidence. ESGE/ESGAR do not suggest CCE as a first-line screening test for colorectal cancer. Weak recommendation, low quality evidence.5. ESGE/ESGAR recommend CTC in the case of a positive fecal occult blood test (FOBT) or FIT with incomplete or unfeasible colonoscopy, within organized population screening programs. Strong recommendation, moderate quality evidence. ESGE/ESGAR also suggest the use of CCE in this setting based on availability. Weak recommendation, moderate quality evidence.6. ESGE/ESGAR suggest CTC with intravenous contrast medium injection for surveillance after curative-intent resection of colorectal cancer only in patients in whom colonoscopy is contraindicated or unfeasible. Weak recommendation, low quality evidence. There is insufficient evidence to recommend CCE in this setting. Very low quality evidence.7. ESGE/ESGAR suggest CTC in patients with high risk polyps undergoing surveillance after polypectomy only when colonoscopy is unfeasible. Weak recommendation, low quality evidence. There is insufficient evidence to recommend CCE in post-polypectomy surveillance. Very low quality evidence.8. ESGE/ESGAR recommend against CTC in patients with acute colonic inflammation and in those who have recently undergone colorectal surgery, pending a multidisciplinary evaluation. Strong recommendation, low quality evidence.9. ESGE/ESGAR recommend referral for endoscopic polypectomy in patients with at least one polyp ≥6 mm detected at CTC or CCE. Follow-up CTC may be clinically considered for 6-9-mm CTC-detected lesions if patients do not undergo polypectomy because of patient choice, comorbidity, and/or low risk profile for advanced neoplasia. Strong recommendation, moderate quality evidence. Source and scope This is an update of the 2014-15 Guideline of the European Society of Gastrointestinal Endoscopy (ESGE) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR). It addresses the clinical indications for the use of imaging alternatives to standard colonoscopy. A targeted literature search was performed to evaluate the evidence supporting the use of computed tomographic colonography (CTC) or colon capsule endoscopy (CCE). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence.

Imaging alternatives to colonoscopy: CT colonography and colon capsule. European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline - Update 2020.

1: ESGE/ESGAR recommend computed tomographic colonography (CTC) as the radiological examination of choice for the diagnosis of colorectal neoplasia.Strong recommendation, high quality evidence.ESGE/ESGAR do not recommend barium enema in this setting.Strong recommendation, high quality evidence. 2: ESGE/ESGAR recommend CTC, preferably the same or next day, if colonoscopy is incomplete. The timing depends on an interdisciplinary decision including endoscopic and radiological factors.Strong recommendation, low quality evidence.ESGE/ESGAR suggests that, in centers with expertise in and availability of colon capsule endoscopy (CCE), CCE preferably the same or the next day may be considered if colonoscopy is incomplete.Weak recommendation, low quality evidence. 3: When colonoscopy is contraindicated or not possible, ESGE/ESGAR recommend CTC as an acceptable and equally sensitive alternative for patients with alarm symptoms.Strong recommendation, high quality evidence.Because of lack of direct evidence, ESGE/ESGAR do not recommend CCE in this situation.Very low quality evidence.ESGE/ESGAR recommend CTC as an acceptable alternative to colonoscopy for patients with non-alarm symptoms.Strong recommendation, high quality evidence.In centers with availability, ESGE/ESGAR suggests that CCE may be considered in patients with non-alarm symptoms.Weak recommendation, low quality evidence. 4: Where there is no organized fecal immunochemical test (FIT)-based population colorectal screening program, ESGE/ESGAR recommend CTC as an option for colorectal cancer screening, providing the screenee is adequately informed about test characteristics, benefits, and risks, and depending on local service- and patient-related factors.Strong recommendation, high quality evidence.ESGE/ESGAR do not suggest CCE as a first-line screening test for colorectal cancer.Weak recommendation, low quality evidence. 5: ESGE/ESGAR recommend CTC in the case of a positive fecal occult blood test (FOBT) or FIT with incomplete or unfeasible colonoscopy, within organized population screening programs.Strong recommendation, moderate quality evidence.ESGE/ESGAR also suggest the use of CCE in this setting based on availability.Weak recommendation, moderate quality evidence. 6: ESGE/ESGAR suggest CTC with intravenous contrast medium injection for surveillance after curative-intent resection of colorectal cancer only in patients in whom colonoscopy is contraindicated or unfeasibleWeak recommendation, low quality evidence.There is insufficient evidence to recommend CCE in this setting.Very low quality evidence. 7: ESGE/ESGAR suggest CTC in patients with high risk polyps undergoing surveillance after polypectomy only when colonoscopy is unfeasible.Weak recommendation, low quality evidence.There is insufficient evidence to recommend CCE in post-polypectomy surveillance.Very low quality evidence. 8: ESGE/ESGAR recommend against CTC in patients with acute colonic inflammation and in those who have recently undergone colorectal surgery, pending a multidisciplinary evaluation.Strong recommendation, low quality evidence. 9: ESGE/ESGAR recommend referral for endoscopic polypectomy in patients with at least one polyp ≥ 6 mm detected at CTC or CCE.Follow-up CTC may be clinically considered for 6 - 9-mm CTC-detected lesions if patients do not undergo polypectomy because of patient choice, comorbidity, and/or low risk profile for advanced neoplasia.Strong recommendation, moderate quality evidence.

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

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

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

PURPOSE: Surveillance CT colonography (CTC) is a viable option for 6-9 mm polyps at CTC screening for colorectal cancer. We established participation and diagnostic yield of surveillance and determined overall yield of CTC screening. MATERIAL AND METHODS: In an invitational CTC screening trial 82 of 982 participants harboured 6-9 mm polyps as the largest lesion(s) for which surveillance CTC was advised. Only participants with one or more lesion(s) ≥6 mm at surveillance CTC were offered colonoscopy (OC); 13 had undergone preliminary OC. The surveillance CTC yield was defined as the number of participants with advanced neoplasia in the 82 surveillance participants, and was added to the primary screening yield. RESULTS: Sixty-five of 82 participants were eligible for surveillance CTC of which 56 (86.2 %) participated. Advanced neoplasia was diagnosed in 15/56 participants (26.8 %) and 9/13 (69.2 %) with preliminary OC. Total surveillance yield was 24/82 (29.3 %). No carcinomas were detected. Adding surveillance results to initial screening CTC yield significantly increased the advanced neoplasia yield per 100 CTC participants (6.1 to 8.6; p < 0.001) and per 100 invitees (2.1 to 2.9; p < 0.001). CONCLUSION: Surveillance CTC for 6-9 mm polyps has a substantial yield of advanced adenomas and significantly increased the CTC yield in population screening. KEY POINTS: • The participation rate in surveillance CT colonography (CTC) is 86 %. • Advanced adenoma prevalence in a 6-9 mm CTC surveillance population is high. • Surveillance CTC significantly increases the yield of population screening by CTC. • Surveillance CTC for 6-9 mm polyps is a safe strategy. • Surveillance CTC is unlikely to yield new important extracolonic findings.

Evolution of Screen-Detected Small (6-9 mm) Polyps After a 3-Year Surveillance Interval: Assessment of Growth With CT Colonography Compared With Histopathology.

OBJECTIVES: Volumetric growth assessment has been proposed for predicting advanced histology at surveillance computed tomography (CT) colonography (CTC). We examined whether is it possible to predict which small (6-9 mm) polyps are likely to become advanced adenomas at surveillance by assessing volumetric growth. METHODS: In an invitational population-based CTC screening trial, 93 participants were diagnosed with one or two 6-9 mm polyps as the largest lesion(s). They were offered a 3-year surveillance CTC. Participants in whom surveillance CTC showed lesion(s) of ≥6 mm were offered colonoscopy. Volumetric measurements were performed on index and surveillance CTC, and polyps were classified into growth categories according to ±30% volumetric change (>30% growth as progression, 30% growth to 30% decrease as stable, and >30% decrease as regression). Polyp growth was related to histopathology. RESULTS: Between July 2012 and May 2014, 70 patients underwent surveillance CTC after a mean surveillance interval of 3.3 years (s.d. 0.3; range 3.0-4.6 years). In all, 33 (35%) of 95 polyps progressed, 36 (38%) remained stable, and 26 (27%) regressed, including an apparent resolution in 13 (14%) polyps. In 68 (83%) of the 82 polyps at surveillance, histopathology was obtained; 15 (47%) of 32 progressing polyps were advanced adenomas, 6 (21%) of 28 stable polyps, and none of the regressing polyps. CONCLUSIONS: The majority of 6-9 mm polyps will not progress to advanced neoplasia within 3 years. Those that do progress to advanced status can in particular be found among the lesions that increased in size on surveillance CTC.

CT colonography: accuracy, acceptance, safety and position in organised population screening.

Colorectal cancer (CRC) is the second most common cancer and second most common cause of cancer-related deaths in Europe. The introduction of CRC screening programmes using stool tests and flexible sigmoidoscopy, have been shown to reduce CRC-related mortality substantially. In several European countries, population-based CRC screening programmes are ongoing or being rolled out. Stool tests like faecal occult blood testing are non-invasive and simple to perform, but are primarily designed to detect early invasive cancer. More invasive tests like colonoscopy and CT colonography (CTC) aim at accurately detecting both CRC and cancer precursors, thus providing for cancer prevention. This review focuses on the accuracy, acceptance and safety of CTC as a CRC screening technique and on the current position of CTC in organised population screening. Based on the detection characteristics and acceptability of CTC screening, it might be a viable screening test. The potential disadvantage of radiation exposure is probably overemphasised, especially with newer technology. At this time-point, it is not entirely clear whether the detection of extracolonic findings at CTC is of net benefit and is cost effective, but with responsible handling, this may be the case. Future efforts will seek to further improve the technique, refine appropriate diagnostic algorithms and study cost-effectiveness.

Clinical indications for computed tomographic colonography: European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline.

This is an official guideline of the European Society of Gastrointestinal Endoscopy (ESGE) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR). It addresses the clinical indications for the use of computed tomographic colonography (CTC). A targeted literature search was performed to evaluate the evidence supporting the use of CTC. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence. Main recommendations 1 ESGE/ESGAR recommend computed tomographic colonography (CTC) as the radiological examination of choice for the diagnosis of colorectal neoplasia. ESGE/ESGAR do not recommend barium enema in this setting (strong recommendation, high quality evidence). 2 ESGE/ESGAR recommend CTC, preferably the same or next day, if colonoscopy is incomplete. Delay of CTC should be considered following endoscopic resection. In the case of obstructing colorectal cancer, preoperative contrast-enhanced CTC may also allow location or staging of malignant lesions (strong recommendation, moderate quality evidence). 3 When endoscopy is contraindicated or not possible, ESGE/ESGAR recommend CTC as an acceptable and equally sensitive alternative for patients with symptoms suggestive of colorectal cancer (strong recommendation, high quality evidence). 4 ESGE/ESGAR recommend referral for endoscopic polypectomy in patients with at least one polyp  ≥  6  mm in diameter detected at CTC. CTC surveillance may be clinically considered if patients do not undergo polypectomy (strong recommendation, moderate quality evidence). 5 ESGE/ESGAR do not recommend CTC as a primary test for population screening or in individuals with a positive first-degree family history of colorectal cancer (CRC). However, it may be proposed as a CRC screening test on an individual basis providing the screenee is adequately informed about test characteristics, benefits, and risks (weak recommendation, moderate quality evidence).

Visceral adipose tissue: the link with esophageal adenocarcinoma.

OBJECTIVE: There is strong evidence for an association between obesity and esophageal adenocarcinoma (EAC). This study investigated the association between directly measured visceral adipose tissue and the risk of EAC. METHODS: In a case-control setting, we measured visceral adipose tissue in patients with EAC and healthy controls. Visceral adipose tissue was determined by abdominal CT. Exclusion criteria were uninterpretable CT scans and severe comorbidity. Controls were healthy volunteers undergoing screening CT colonography. Cross-sectional areas of visceral and subcutaneous adipose tissues were measured in cm(2) at L3/L4. Values of adipose tissue of EAC patients were extrapolated to stage 0 and compared to controls. The association between visceral adipose tissue and EAC was calculated with least-squares regression, adjusted for age, sex and TNM stage. RESULTS: We included 175 EAC patients and 251 controls. While body mass index was similar in EAC patients (26.1 kg/m(2)) and controls (26.2 kg/m(2)), visceral adipose tissue was significantly higher in EAC patients at stage 0 than in controls (276 vs. 231 cm(2); p = 0.015). Regarding subcutaneous adipose tissue, there was no difference. CONCLUSIONS: Patients with EAC have significantly higher visceral adipose tissue than healthy controls. Visceral adipose tissue is a risk factor in the development of EAC and seems to be more important than obesity alone.

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

CT colonography (CTC) is one of the recommended methods for colorectal cancer screening. The subject's preparation is one of the most burdensome aspects of CTC with a cathartic bowel preparation. Tagging of the bowel content with an oral contrast medium facilitates CTC with limited bowel preparation. Unfortunately, such preparations adversely affect the 3-D image quality. Thus far, data acquired after very limited bowel preparation were evaluated with a 2-D reading strategy only. Existing cleansing algorithms do not work sufficiently well to allow a primary 3-D reading strategy. We developed an electronic cleansing algorithm, aimed to realize optimal 3-D image quality for low-dose CTC with 24-h limited bowel preparation. The method employs a principal curvature flow algorithm to remove heterogeneities within poorly tagged fecal residue. In addition, a pattern recognition-based approach is used to prevent polyp-like protrusions on the colon surface from being removed by the method. Two experts independently evaluated 40 CTC cases by means of a primary 2-D approach without involvement of electronic cleansing as well as by a primary 3-D method after electronic cleansing. The data contained four variations of 24-h limited bowel preparation and was based on a low radiation dose scanning protocol. The sensitivity for lesions ≥ 6 mm was significantly higher for the primary 3-D reading strategy (84%) than for the primary 2-D reading strategy (68%) (p = 0.031). The reading time was increased from 5:39 min (2-D) to 7:09 min (3-D) (p = 0.005); the readers' confidence was reduced from 2.3 (2-D) to 2.1 (3-D) ( p = 0.013) on a three-point Likert scale. Polyp conspicuity for cleansed submerged lesions was similar to not submerged lesions (p = 0.06). To our knowledge, this study is the first to describe and clinically validate an electronic cleansing algorithm that facilitates low-dose CTC with 24-h limited bowel preparation.

Informed decision-making in colorectal cancer screening using colonoscopy or CT-colonography.

OBJECTIVE: To evaluate the level of informed decision making in a randomized controlled trial comparing colonoscopy and CT-colonography for colorectal cancer screening. METHODS: 8844 citizens aged 50-75 were randomly invited to colonoscopy (n=5924) or CT-colonography (n=2920) screening. All invitees received an information leaflet. Screenees received a questionnaire within 4 weeks before the planned examination, non-screenees 4 weeks after the invitation. A decision was categorized as informed when characterized by sufficient decision-relevant knowledge and consistent with personal attitudes toward participation in screening. RESULTS: Knowledge and attitude items were completed by 1032/1276 colonoscopy screenees (81%), by 698/4648 colonoscopy non-screenees (15%), by 824/982 CT-colonography screenees (84%) and by 192/1938 CT-colonography non-screenees (10%). 1027 colonoscopy screenees (>99%) and 815 CT-colonography screenees (99%) had adequate knowledge; 915 (89%) and 742 (90%) had a positive attitude. 675 non-screenees invited to colonoscopy (97%) and 182 invited to CT-colonography (95%) had adequate knowledge; 344 (49%) and 94 (49%) expressed a negative attitude. CONCLUSION: A large majority of screenees made an informed decision on participation. Almost half of responding non-screenees, made an uninformed decision, suggesting additional barriers to participation. PRACTICE IMPLICATIONS: Efforts to understand the additional barriers will create opportunities to facilitate informed participation to colorectal cancer screening.

Overinterpretation and misreporting of diagnostic accuracy studies: evidence of "spin".

PURPOSE: To estimate the frequency of distorted presentation and overinterpretation of results in diagnostic accuracy studies. MATERIALS AND METHODS: MEDLINE was searched for diagnostic accuracy studies published between January and June 2010 in journals with an impact factor of 4 or higher. Articles included were primary studies of the accuracy of one or more tests in which the results were compared with a clinical reference standard. Two authors scored each article independently by using a pretested data-extraction form to identify actual overinterpretation and practices that facilitate overinterpretation, such as incomplete reporting of study methods or the use of inappropriate methods (potential overinterpretation). The frequency of overinterpretation was estimated in all studies and in a subgroup of imaging studies. RESULTS: Of the 126 articles, 39 (31%; 95% confidence interval [CI]: 23, 39) contained a form of actual overinterpretation, including 29 (23%; 95% CI: 16, 30) with an overly optimistic abstract, 10 (8%; 96% CI: 3%, 13%) with a discrepancy between the study aim and conclusion, and eight with conclusions based on selected subgroups. In our analysis of potential overinterpretation, authors of 89% (95% CI: 83%, 94%) of the studies did not include a sample size calculation, 88% (95% CI: 82%, 94%) did not state a test hypothesis, and 57% (95% CI: 48%, 66%) did not report CIs of accuracy measurements. In 43% (95% CI: 34%, 52%) of studies, authors were unclear about the intended role of the test, and in 3% (95% CI: 0%, 6%) they used inappropriate statistical tests. A subgroup analysis of imaging studies showed 16 (30%; 95% CI: 17%, 43%) and 53 (100%; 95% CI: 92%, 100%) contained forms of actual and potential overinterpretation, respectively. CONCLUSION: Overinterpretation and misreporting of results in diagnostic accuracy studies is frequent in journals with high impact factors. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120527/-/DC1.

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

This article reviews two important aspects of CT-colonography, namely colonic distension and scan parameters. Adequate distension should be obtained to visualize the complete colonic lumen and optimal scan parameters should be used to prevent unnecessary radiation burden. For optimal distension, automatic carbon dioxide insufflation should be performed, preferably via a thin, flexible catheter. Hyoscine butylbromide is - when available - the preferred spasmolytic agent because of the positive effect on insufflation and pain/burden and its low costs. Scans in two positions are required for adequate distension and high polyp sensitivity and decubitus position may be used as an alternative for patients unable to lie in prone position. The great intrinsic contrast between air or tagging and polyps allows the use of low radiation dose. Low-dose protocol without intravenous contrast should be used when extracolonic findings are deemed unimportant. In patients suspected for colorectal cancer, normal abdominal CT scan protocols and intravenous contrast should be used in supine position for the evaluation of extracolonic findings. Dose reduction can be obtained by lowering the tube current and/or voltage. Tube current modulation reduces the radiation dose (except in obese patients), and should be used when available. Iterative reconstructions is a promising dose reducing tool and dual-energy CT is currently evaluated for its applications in CT-colonography. This review also provides our institution's insufflation procedure and scan parameters.

Reasons for participation and nonparticipation in colorectal cancer screening: a randomized trial of colonoscopy and CT colonography.

OBJECTIVES: We compared reported reasons for participation and nonparticipation in colorectal cancer (CRC) screening between colonoscopy and computed tomographic (CT) colonography in a randomized controlled trial. METHODS: We randomly invited 8,844 people for screening by colonoscopy or CT colonography. On a questionnaire, invitees indicated reasons for participation or nonparticipation and indicated the most decisive reason. RESULTS: The most frequently cited reasons to accept screening were early detection of precursor lesions and CRC, and contribution to science. The most frequently cited reasons to decline were the unpleasantness of the examination, the inconvenience of the preparation, a lack of symptoms, and "no time/too much effort." Among colonoscopy nonparticipants, elderly invitees cited inconvenience less often, and absence of symptoms more often, than did the group overall. The reason reported most frequently as the most decisive reason not to participate was the unpleasantness of the examination among colonoscopy nonparticipants, and "no time/too much effort" and lack of symptoms among CT colonography nonparticipants. CONCLUSIONS: In light of these results, future screening programs could tailor the information provided to invitees.

Comparing the diagnostic yields of technologists and radiologists in an invitational colorectal cancer screening program performed with CT colonography.

PURPOSE: To compare the diagnostic yields of a radiologist and trained technologists in the detection of advanced neoplasia within a population-based computed tomographic (CT) colonography screening program. MATERIALS AND METHODS: Ethical approval was obtained from the Dutch Health Council, and written informed consent was obtained from all participants. Nine hundred eighty-two participants (507 men, 475 women) underwent low-dose CT colonography after noncathartic bowel preparation (iodine tagging) between July 13, 2009, and January 21, 2011. Each scan was evaluated by one of three experienced radiologists (≥800 examinations) by using primary two-dimensional (2D) reading followed by secondary computer-aided detection (CAD) and by two of four trained technologists (≥200 examinations, with colonoscopic verification) by using primary 2D reading followed by three-dimensional analysis and CAD. Immediate colonoscopy was recommended for participants with lesions measuring at least 10 mm, and surveillance was recommended for participants with lesions measuring 6-9 mm. Consensus between technologists was achieved in case of discordant recommendations. Detection of advanced neoplasia (classified by a pathologist) was defined as a true-positive (TP) finding. Relative TP and false-positive (FP) fractions were calculated along with 95% confidence intervals (CIs). RESULTS: Overall, 96 of the 982 participants were referred for colonoscopy and 104 were scheduled for surveillance. Sixty of 84 participants (71%) referred for colonoscopy by the radiologist had advanced neoplasia, compared with 55 of 64 participants (86%) referred by two technologists. Both the radiologist and technologists detected all colorectal cancers (n = 5). The relative TP fraction (for technologists vs radiologist) for advanced neoplasia was 0.92 (95% CI: 0.78, 1.07), and the relative FP fraction was 0.38 (95% CI: 0.21, 0.67). CONCLUSION: Two technologists serving as a primary reader of CT colonographic images can achieve a comparable sensitivity to that of a radiologist for the detection of advanced neoplasia, with far fewer FP referrals for colonoscopy.

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

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