Diagnostic Performance and Patient Acceptance of Reduced-Laxative CT Colonography for the Detection of Polypoid and Non-Polypoid Neoplasms: A Multicenter Prospective Trial

CT colonography has advantages over colonoscopy for size measurement of colorectal polyps

PURPOSE

The aim of this study was to compare the accuracy of colonoscopy (CS) and CT colonography (CTC) in the measurement of colorectal polyps using pathological size as a reference.

MATERIALS AND METHODS

The analysis included 61 colorectal polyps in 28 patients who underwent preoperative CTC at our institution. All polyps were endoscopically resected. Polyp sizes were measured by CS and CTC. Endoscopic polyp size was extracted from endoscopy records written by one of two endoscopists (A with 11 and B with 6 years of endoscopic experience, respectively), who estimated the size visually/categorically without any measuring devices. After matching the location, the polyp size was measured on CTC using manual three-dimensional (3D) measurement on a workstation. The sizes of resected polyps were also measured after pathological inspection. Differences of the polyp size between CTC and histology, and between CS and histology were compared using paired t tests. Differences in measurement between the two endoscopists were also analyzed.

RESULTS

The mean diameters of polyps measured using CS, CTC, and pathology were 10.5 mm, 9.2 mm, and 8.4 mm, respectively. There was a significant correlation between CS and pathology, as well as between CTC and pathology (both P < 0.0001). The correlation coefficient for CS (r = 0.86) was lower than that for CTC (r = 0.96). The correlations between CS and pathology for endoscopists A and B were 0.90 and 0.89, respectively.

CONCLUSION

Measurements of polyp size using CTC were closer to the pathological measurements compared to those by CS, which exhibited greater variability. This suggests that CTC may be more suitable for polyp size measurements in the clinical setting if patients undergo CTC concurrently with colonoscopy.

Acceptance and Preference of Computed Tomographic Colonography and Colonoscopy: Results of a Nationwide Multicenter Comparative Questionnaire Survey in Japan

Objectives

To investigate patient acceptance and preference for computed tomographic colonography (CTC) over colonoscopy.

Methods

Participants were recruited from a nationwide multicenter trial in Japan to assess the accuracy of CTC detection. They were scheduled to undergo colonoscopy after CTC with common bowel preparation on the same day. Some were administered sedative drugs during colonoscopy, depending on the referring clinician and participant's preferences. The participants were requested to complete a questionnaire to evaluate the acceptability of bowel preparation, examinations, and preference for future examinations.

Results

Of the 1,257 enrolled participants, 1,180 (mean age: 60.6 years; women: 43.3%) completed the questionnaire. Sedative drugs were not administered in 687 participants (unsedated colonoscopy group) and were administered intravenously during colonoscopy in 493 participants (sedated colonoscopy group). Before propensity score matching, the mean participants' age, percentages of asymptomatic participants, insufflation of gas during colonoscopy, and number of participants with a history of abdominal/pelvic operation significantly differed between the groups. After propensity score matching, 912 participants from each group were included in the analysis. In the unsedated colonoscopy group, CTC was answered as significantly easier than colonoscopy (p<0.001). Conversely, CTC was significantly more difficult than colonoscopy in the sedated colonoscopy group (p<0.001). In the unsedated colonoscopy group, 48% preferred CTC and 22% preferred colonoscopy for future examinations, whereas in the sedated colonoscopy group, 26% preferred CTC and 38% preferred colonoscopy (p<0.001).

Conclusions

CTC has superior participant acceptability compared with unsedated colonoscopy. However, our study did not observe the advantages of CTC acceptance over sedative colonoscopy.

Comparison of Diatrizoate and Iohexol for Patient Acceptance and Fecal-Tagging Performance in Noncathartic CT Colonography

OBJECTIVE

The aim of this study was to compare diatrizoate and iohexol regarding patient acceptance and fecal-tagging performance in noncathartic computed tomography colonography.

METHODS

This study enrolled 284 volunteers with fecal tagging by either diatrizoate or iohexol at an iodine concentration of 13.33 mg/mL and an iodine load of 24 g. Patient acceptance was rated on a 4-point scale of gastrointestinal discomfort. Two gastrointestinal radiologists jointly analyzed image quality, fecal-tagging density and homogeneity, and residual contrast agent in the small intestine. The results were compared by the generalized estimating equation method.

RESULTS

Patient acceptance was comparable between the 2 groups (3.95 ± 0.22 vs 3.96 ± 0.20, P = 0.777). The diatrizoate group had less residual fluid and stool than the iohexol group ( P = 0.019, P = 0.004, respectively). There was no significant difference in colorectal distention, residual fluid, and stool tagging quality between the 2 groups (all P 's > 0.05). The mean 2-dimensional image quality score was 4.59 ± 0.68 with diatrizoate and 3.60 ± 1.14 with iohexol ( P < 0.001). The attenuation of tagged feces was 581 ± 66 HU with diatrizoate and 1038 ± 117 HU with iohexol ( P < 0.001). Residual contrast agent in the small intestine was assessed at 55.3% and 62.3% for the diatrizoate group and iohexol group, respectively ( P = 0.003).

CONCLUSIONS

Compared with iohexol, diatrizoate had better image quality, proper fecal-tagging density, and more homogeneous tagging along with comparable excellent patient acceptance, and might be more suitable for fecal tagging in noncathartic computed tomography colonography.

Diagnostic accuracy of ultra-low-dose CT colonography for the detection of colorectal polyps: a feasibility study

PURPOSE

The aim of this feasibility study was to evaluate the diagnostic accuracy of ultra-low-dose CT colonography using iterative reconstruction algorithms with reference to standard colonoscopy.

MATERIALS AND METHODS

Prior to this study, a phantom study was performed to investigate the optimal protocol for ultra-low-dose CT colonography. A total of 206 patients with average/high risk of colorectal cancer were recruited. After undergoing full bowel preparation, the patients were scanned in the prone and supine positions with the CT conditions set to 120 kV, standard deviation 45 to 50, and an adaptive iterative reconstruction algorithm applied. Two expert readers read the images independently. The main outcome measures were the per-patient and per-polyp accuracies for the detection of polyps ≥ 10 mm, with colonoscopy results as the reference standard.

RESULTS

Two hundred patients (102 females, mean age 67.5 years) underwent both ultra-low-dose CT colonography and colonoscopy on the same day. The mean radiation exposure dose was 0.64 ± 0.34 mSv. On colonoscopy, 39 patients had 45 polyps ≥ 10 mm (non-polypoid morphology 7), including 4 cancers. Per-patient sensitivity, specificity, and accuracy of CT colonography for polyps ≥ 10 mm were 0.74, 0.96, and 0.92 for reader one, and 0.74, 0.99, and 0.94 for reader two, respectively. Per-polyp sensitivities for polyps ≥ 10 mm were 0.73 for reader one and 0.71 for reader two. On subgroup analysis by morphology, non-polypoid polyps ≥ 10 mm were not detected by both readers.

CONCLUSION

Extreme ultra-low-dose CT colonography had an insufficient diagnostic performance for the detection of polyps ≥ 10 mm, because it was unable to detect non-polypoid polyps. This study showed that the problem with ultra-low-dose CT colonography was the lack of detectability of small-size polyps, especially non-polypoid polyps. To use ultra-low-dose CT colonography clinically, it is necessary to resolve the problems identified by this study.

Bowel habits and gender correlate with colon length measured by CT colonography

PURPOSE

CT colonography enables three-dimensional measurement of colon length. However, previous studies using CT colonography have not examined the association with gender, age, physique, a history of laparotomy and bowel habits, all possible contributory factors to colon length. The aim of this study is to investigate factors associated with colon length.

MATERIALS AND METHODS

We conducted a post hoc analysis based on data obtained from a previous multi-center trial including 321 patients with positive fecal immunochemical tests who underwent CT colonography. Colon length was measured using a computer-generated center line and was divided at the iliac crest level into the distal and proximal colons. Bowel habits were classified into three groups: A-daily; B-once every 2 or 3 days; and C-less than once in 3 days. Statistical comparison was made using one-way ANOVA with Bonferroni's correction.

RESULTS

A total of 295 patients were analyzed. The entire colon length (cm, mean ± standard deviation) of individual patients was 150.3 ± 18.5 cm and ranged from 109.7 to 195.9 cm. The female colon was significantly longer than the male colon (154.3 ± 18.1 cm vs. 147.1 ± 18.3 cm; p = 0.022). Colon length showed trends associated with age (p = 0.18) and a history of laparotomy (p = 0.14). According to bowel habits, the entire colon measured 147.4 ± 17.9 in group A, 154.7 ± 18.5 in group B and 158.6 ± 18.3 in group C, and significant differences were observed for "A vs. C" (p = 0.002) and "A vs. B" (p = 0.014). In subgroup analysis by colon segment, the proximal colon trended similarly to the entire colon while there were no trends for the distal colon.

CONCLUSIONS

This study has clearly demonstrated that bowel habits and gender both correlate with the length of the entire colon measured by CT colonography, and in particular, the proximal colon. Using CT colonography, we measured the colon length in 295 patients. The entire colon length was 150.3 ± 18.5 cm on average. Females and constipated (less frequent defecation) patients have a significantly longer colon, and in particular, the proximal colon. Colon length showed trends associated with age and a history of laparotomy.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis treatment and follow-up of patients with localised colon cancer

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of localised colon cancer was published in 2020. It was decided by both the ESMO and the Japanese Society of Medical Oncology (JSMO) to convene a special virtual guidelines meeting in March 2021 to adapt the ESMO 2020 guidelines to take into account the ethnic differences associated with the treatment of localised colon cancer in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with localised colon cancer representing the oncological societies of Japan (JSMO), China (CSCO), India (ISMPO), Korea (KSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence and was independent of the current treatment practices and drug availability and reimbursement situations in the different Asian countries.

Low-volume reduced bowel preparation regimen for CT colonography: a randomized noninferiority trial

PURPOSE

To determine whether the quality of a low-volume reduced bowel preparation (LV-RBP) for CT Colonography (CTC) is noninferior to full-volume reduced bowel preparation (FV-RBP) regimen.

METHODS

In this randomized controlled trial, consecutive participants referred for CTC were randomly assigned to receive LV-RBP (52.5 g of PMF104 in 500 mL of water) or FV-RBP (105 g of PMF104 in 1000 mL of water). Images were independently reviewed by five blinded readers who rated the quality of bowel preparation from 0 (best score) to 3 (worst score). The primary outcome was the noninferiority of LV-RBP to FV-RBP in the proportion of colonic segments scored 0 for cleansing quality, with noninferiority margin of 10%. Volume of residual fluids, colonic distension, lesions and polyps detection rates and patient tolerability were secondary outcomes.

RESULTS

From March 2019 to January 2020, 110 participants (mean age 65 years ± 14 [standard deviation]; 74 women) were allocated to LV-RBP (n = 55) or FV-RBP (n = 55) arms. There were 92% segment scored 0 in colon cleansing quality in LV-RBP and 94% in FV-RBP for prone scans, and 94% vs 92% for supine scans. Risk difference was - 2.1 (95% CI -5.9 to 1.7) and 1.5 (95% CI -2.4 to 5.4) for prone and supine positions, respectively. Residual fluids and colonic distension were also noninferior in LV-RBP. LV-RBP was associated with a lower number of evacuations during preparation (7 ± 5 vs 10 ± 6, p = 0.002).

CONCLUSION

The LV-RBP for CTC demonstrated noninferior quality of colon cleansing with improved gastrointestinal tolerability compared to FV-RBP regimen.

Ultrathin colonoscopy can improve complete preoperative colonoscopy for stenotic colorectal cancer: Prospective observational study

OBJECTIVES

Preoperative colonoscopy is often incomplete for stenotic colorectal cancers (CRC). This prospective observational study aimed to evaluate the ability of an ultrathin colonoscope (UTC) to inspect the whole colon by passing through the stenotic CRC.

METHODS

All patients who underwent preoperative colonoscopy for stenotic CRCs at Shizuoka Cancer Center were examined for eligibility. If a standard colonoscope (PCF-H290ZI) could not pass because of a stenosis, the patients were recruited. All of the eligible patients were prospectively enrolled when informed consent could be obtained, and complete colonoscopy was attempted again using an UTC (PCF-PQ260L). Patients with stent placement and those requiring right hemicolectomy were not recruited. Primary endpoints were pass-through and cecal intubation rates. The detected synchronous neoplasias (adenomas and cancers) and their pathological findings after resection were evaluated.

RESULTS

A total of 100 patients were enrolled between September 2017 and February 2019. The mean age was 65.6 ± 10.8 years, and 59% were male. The pass-through and cecal intubation rates were 67% (67/100) and 58% (58/100), respectively. Synchronous lesions located proximal to the stenoses were detected in 65.5% (38/58) of the complete colonoscopies, with a total of 86 lesions, including 18 advanced neoplasias with three invasive cancers.

CONCLUSION

When standard colonoscopy cannot pass through stenotic CRC, ultrathin colonoscopy can be considered as an option to inspect the whole colon proximal to the stenosis because treatment strategy can potentially be changed by detecting synchronous neoplasias proximal to the stenosis before surgery. (UMIN000028505).

[Effect of Matrix Size on Lesion Detectability in CT Colonography]

OBJECTIVES

While computed tomography colonography (CTC) has become a non-invasive alternative to traditional colonoscopy, superficial lesions tend to be harder to detect, with reports of lesions <2 mm in height being missed. Therefore, for the evaluation of lesion detectability using CTC, optimizing scan parameters becomes important. In this study, we investigate the effect of the reconstructed matrix size from CTC on the lesion conspicuity.

METHODS

A CTC phantom was scanned, and images were reconstructed with 512, 768 and 1024 matrix sizes with the same raw data. The image data in each matrix size were compared in terms of physical assessment of the task-transfer function (TTF) and the noise power spectrum (NPS), and of visual assessment using Scheffé's paired comparison.

RESULTS

Comparing 768 and 1024 matrix sizes with that of 512, NPS was higher in high-frequency components. On the other hand, TTF was improved using these larger matrix sizes along with significant statistical differences in the visual assessment.

CONCLUSION

Larger matrix sizes (768 and 1024) improve the lesion conspicuity, thereby helping to detect superficial and small lesions (size<2 mm) in CTC.

Diagnostic accuracy of computed tomography colonography in patients at high risk for colorectal cancer: a meta-analysis

AIM

The aim was to explore the diagnostic value of computed tomographic colonography (CTC) compared with conventional colonoscopy in individuals at high risk for colorectal cancer.

METHOD

PubMed, Embase, the Cochrane Library and the Web of Science were searched by two independent reviewers for potentially eligible studies published up to 31 October 2018 that were based on a per-patient analysis. stata, meta-disc and revman were used to perform this meta-analysis. A random-effect model was used, and a subgroup analysis was conducted to explore the sources of heterogeneity.

RESULTS

A total of 14 full-text articles, involving 3578 patients, were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and the area under the summary receiver operating characteristic curve of CTC for detecting polyps ≥ 6 mm were 0.87 (95% CI 0.83-0.90), 0.90 (95% CI 0.86-0.93), 9.08 (95% CI 6.28-13.13), 0.14 (95% CI 0.11-0.18) and 0.94 (95% CI 0.92-0.96), respectively. For polyps ≥ 10 mm, the pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of CTC were 0.91 (95% CI 0.86-0.94), 0.98 (95% CI 0.95-0.99), 40.36 (95% CI 19.16-85.03), 0.90 (95% CI 0.06-0.14) and 0.98 (95% CI 0.96-0.99), respectively.

CONCLUSION

In this meta-analysis, CTC had high diagnostic accuracy for detecting polyps ≥ 6 mm and ≥ 10 mm in patients at high risk of developing colorectal cancer and it had a higher sensitivity and specificity for detecting polyps ≥ 10 mm than polyps ≥ 6 mm. However, the results should be used cautiously due to the significant heterogeneity.

Comparison of two Meglumine-Diatrizoate based bowel preparations for computed tomography colonography: Comparison of patient symptoms and bowel preparation quality

INTRODUCTION

To investigate the impact of two Meglumine-Diatrizoate based bowel preparation regimes for computed tomography colonography (CTC) on the patient experience and image quality.

METHODS

100 patients consumed Meglumine-Diatrizoate at 24 h and 12 h prior to the CTC examination. 50 patients followed regime 1 (50:50), 50 ml of Meglumine-Diatrizoate at both 24 and 12 h prior to the examination. 50 patients followed regime 2 (75:25), 75 ml of Meglumine-Diatrizoate at 24 h prior to the examination and 25 ml of Meglumine-Diatrizoate at 12 h prior to the examination. All patients completed a questionnaire to indicate the time of onset of adverse effects and when they were most severe. Five advanced practitioners assessed the image quality in a visual grading study. Visual grading characteristic (VGC) analysis was applied with regime 1 as the reference condition and regime 2 and test condition; test alpha was set at 0.05.

RESULTS

Image quality was assessed with successful bowel cleansing as the scoring criteria for the visual grading study. The bowel cleansing as provided by the two Meglumine-Diatrizoate regimes was revealed not to be statistically different, with the area under the VGC curve and 95% confidence intervals 0.487 (0.287, 0.701), p = 0.887. Patients taking the 75:25 bowel preparation experienced a shorter median time to the onset of adverse effects.

CONCLUSION

There was no observed difference in Image quality criteria score for the two Meglumine-Diatrizoate based bowel preparation with more predictable adverse effects of Meglumine-Diatrizoate with the 75:25 preparation.

IMPLICATIONS FOR PRACTICE

Providing patients with a higher contrast burden 24 h prior to CTC may have a positive impact on the patient experience without compromising image quality.

Preference and Experience of Colonic Examination for Participants Presenting to Hospitals with a Positive Fecal Immunochemical Test Result

PURPOSE

Patients who test positive on the fecal immunochemical test (FIT) for colorectal cancer (CRC) are referred for colonoscopy for further diagnostic evaluation. Colonoscopy is not a perfect method and may be a challenge for some FIT-positive patients. Computed tomographic colonography (CTC) is an alternative method that is less invasive and allows examination of the whole colon. The study objective was to evaluate the preference of FIT-positive patients for either colonoscopy or CTC for CRC examination.

PATIENTS AND METHODS

Individuals older than 40 years with a positive FIT test at eight Japanese hospitals between December 2012 and July 2015 were invited to participate. Participants were given detailed information regarding colonoscopy and CTC before deciding on either examination. They completed questionnaires before the procedure regarding their preference and after the procedure regarding their experience.

RESULTS

The pre- and post-questionnaires of 846 and 834 participants, respectively, were analyzed. Participants preferred colonoscopy over CTC (colonoscopy, 72%; CTC, 28%). The possibility of obtaining biopsy samples and removing colorectal polyps during the procedure was the main reason for colonoscopy selection. Patients selected CTC to reduce discomfort but reported that CTC bowel preparation was more burdensome than colonoscopy bowel preparation. The overall experience of the examination did not differ between the groups.

CONCLUSION

Colonoscopy is the standard examination for FIT-positive patients. However, when given a choice, almost one-third of participants chose CTC because they thought it would be a more "comfortable" examination. Clinicians should therefore be aware of patients' potential preference for noninvasive colorectal examinations.

A novel volume-reduced CT colonography regimen using hypertonic laxative (polyethylene glycol with ascorbic acid): randomized controlled trial

OBJECTIVES

The aim of this study is to investigate the feasibility of bowel preparation using a hypertonic laxative (polyethylene glycol with ascorbic acid, PEG + Asc) for CT colonography (CTC) and to examine the volume limit of laxative.

METHODS

In one institution, patients who met the indications for CTC were enrolled and randomly assigned to CTC with regimen A (800 ml PEG + Asc), B (600 ml PEG + Asc), or C (400 ml PEG + Asc). Sodium diatrizoate was given orally for fecal tagging. On the previous day, patients ate low-residue meals and took the assigned lavage solution after dinner. A reader blinded to the preparation graded residual stool/fluid and fecal tagging quality in six segments of the colorectum. The primary outcome was a proportion of colon segments without stool. One hundred twenty segments in 20 patients with each regimen were needed to show a non-inferiority margin of 15%, assuming 85% of no stool.

RESULTS

A total of 360 segments in 60 patients were analyzed. There were 83% of segments with no stool in regimen A, 89% in regimen B, and 88% in regimen C. Using the delta method, the 95% confidence interval of the risk difference (6.7%) between regimens A and B was - 2.2% to 15.6%, and the risk difference (5.0%) between regimens A and C was - 4.1% to 14%, both within the non-inferiority margin. Residual fluid and fecal tagging quality were also within the non-inferiority margin. No adverse events occurred.

CONCLUSIONS

A novel CTC regimen using hypertonic laxative demonstrated optimal colon cleansing effectiveness even with the lowest volume of laxative (UMIN000022851).

KEY POINTS

• A novel CTC regimen using a hypertonic laxative is feasible. • The lowest volume of laxative provides excellent colon imaging. • However, the lowest volume of laxative did not improve patient acceptance.

Colonic distention and patient acceptance of CT colonography: supine/prone vs left/right lateral scanning

OBJECTIVE

To prospectively evaluate and complete the colonic distention and patient acceptance of CT colonography (CTC) in the supine/prone and left/right lateral positions.

METHODS

A total of 220 consecutive patients were alternately allocated to the supine/prone positioning or left/right lateral positioning group. Two readers scored the degree of colonic distention by segment using a 4-point Likert scale (4 = optimal, 3 = adequate, 2 = inadequate, 1 = collapsed). In addition, patients were asked to rate the discomfort due to positioning during each scan using a 3-point animated face scale (3 = difficult, 2 = somewhat unacceptable, 1 = easy).

RESULTS

The overall mean colonic distention scores for supine, prone, left lateral, and right lateral positions were 3.16, 3.29, 3.22, and 3.42, respectively. Of all, the right lateral position provided the best colonic distention (p < 0.01). Combined left lateral and right lateral positions provided more adequately distended segments compared with combined supine and prone positions (95.6% vs 90.7 %, respectively, p < 0.01). Patient acceptance was significantly lower in the prone position compared to other positions; however there was no difference in patient acceptance between the supine and left/right lateral positions.

CONCLUSION

Right lateral positioning provided the best colonic distention and good patient acceptance.

ADVANCES IN KNOWLEDGE

The left/right lateral position should be considered for routine CTC positioning protocols.

Colon cancer with rapid growth in 16 months confirmed by computed tomographic colonography

This report describes a case of rapidly growing colon cancer confirmed by computed tomographic colonography (CTC). A 75-year-old woman presented at our clinic with complaints of abdominal discomfort and melena. Colorectal examination was performed via CTC. The findings were normal. Sixteen months later, she was referred to our clinic again for positive findings on a faecal immunochemical screening test. A repeat CTC was performed, which revealed a 3 cm ulcerated tumour at the ascending colon. Colonoscopy with biopsy revealed tubular adenocarcinoma. Laparoscopic right hemicolectomy was performed and the TNM classification was found to be T3N1M0. The postoperative course was uneventful, and the cancer has not recurred for 2.5 years.

Effectiveness of computer-aided diagnosis of colorectal lesions using novel software for magnifying narrow-band imaging: a pilot study

BACKGROUND AND STUDY AIMS

 Magnifying narrow-band imaging (M-NBI) enables detailed observation of microvascular architecture and can be used in endoscopic diagnosis of colorectal lesion. However, in clinical practice, differential diagnosis and estimation of invasion depth of colorectal lesions based on M-NBI findings require experience. Therefore, developing computer-aided diagnosis (CAD) for M-NBI would be beneficial for clinical practice. The aim of this study was to evaluate the effectiveness of software for CAD of colorectal lesions.

MATERIALS AND METHODS

In collaboration with Yamaguchi University, we developed novel software that enables CAD of colorectal lesions using M-NBI images. This software for CAD further specifically divides original Sano's colorectal M-NBI classification into 3 groups (group A, capillary pattern [CP] type I; group B, CP type II + CP type IIIA; group C, CP type IIIB), which describe hyperplastic polyps (HPs), adenoma/adenocarcinoma (intramucosal [IM] to submucosal [SM]-superficial) lesions, and SM-deep lesions, respectively. We retrospectively reviewed 121 lesions evaluated using M-NBI.

RESULTS

The 121 reviewed lesions included 21 HP, 80 adenoma/adenocarcinoma (IM to SM-superficial), and 20 SM-deep lesions. The concordance rate between the CAD and the diagnosis of the experienced endoscopists was 90.9 %. The sensitivity, specificity, positive and negative predictive values, and accuracy of the CAD for neoplastic lesions were 83.9 %, 82.6 %, 53.1 %, 95.6 %, and 82.8 %, respectively. The values for SM-deep lesions were 83.9 %, 82.6 %, 53.1 %, 95.6 %, and 82.8 %, respectively.

CONCLUSION

 Relatively high diagnostic values were obtained using CAD. This software for CAD could possibly lead to a wider use of M-NBI in the endoscopic diagnosis of colorectal lesions.

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

OBJECTIVES

To retrospectively evaluate the frequencies and magnitudes of adverse events associated with computed tomographic colonography (CTC) for screening, diagnosis and preoperative staging of colorectal cancer.

METHODS

A Japanese national survey on CTC was administered by use of an online survey tool in the form of a questionnaire. The questions covered mortality, colorectal perforation, vasovagal reaction, total number of examinations, and examination procedures. The survey data was collated and raw frequencies were determined. Fisher's exact test was used to determine differences in event rates between groups.

RESULTS

At 431 institutions, 147,439 CTC examinations were performed. No deaths were reported. Colorectal perforations occurred in 0.014% (21/147,439): 0.003% (1/29,823) in screening, 0.014% (13/91,007) in diagnosis and 0.028% (7/25,330) in preoperative staging. The perforation risk was significantly lower in screening than in preoperative staging CTC procedures (p = 0.028). Eighty-one per cent of perforation cases (17/21) did not require emergency surgery. Vasovagal reaction occurred in 0.081% (120/147,439): 0.111% (33/29,823) in screening, 0.088% (80/91,007) in diagnosis and 0.028% (7/25,330) in preoperative staging.

CONCLUSIONS

The risk of colorectal perforation and vasovagal reaction in CTC is low. The frequency of colorectal perforation associated with CTC is least in the screening group and greatest in the preoperative-staging group.

KEY POINTS

• The colorectal perforation rate during preoperative-staging CTC was 0.028 %. • The perforation rates for screening and diagnosis were 0.003 % and 0.014 %, respectively. • The perforation risk is significantly lower in screening than in preoperative staging. • Eighty-one per cent of perforation cases did not require emergency surgery. • Use of an automatic colon insufflator can reduce the risk of bowel perforation.