Patient experience of CT colonography and colonoscopy after fecal occult blood test in a national screening programme.

OBJECTIVE: To investigate patient experience of CT colonography (CTC) and colonoscopy in a national screening programme. METHODS: Retrospective analysis of patient experience postal questionnaires. We included screenees from a fecal occult blood test (FOBt) based screening programme, where CTC was performed when colonoscopy was incomplete or deemed unsuitable. We analyzed questionnaire responses concerning communication of test risks, test-related discomfort and post-test pain, as well as complications. CTC and colonoscopy responses were compared using multilevel logistic regression. RESULTS: Of 67,114 subjects identified, 52,805 (79 %) responded. Understanding of test risks was lower for CTC (1712/1970 = 86.9 %) than colonoscopy (48783/50975 = 95.7 %, p < 0.0001). Overall, a slightly greater proportion of screenees found CTC unexpectedly uncomfortable (506/1970 = 25.7 %) than colonoscopy (10,705/50,975 = 21.0 %, p < 0.0001). CTC was tolerated well as a completion procedure for failed colonoscopy (unexpected discomfort; CTC = 26.3 %: colonoscopy = 57.0 %, p < 0.001). Post-procedural pain was equally common (CTC: 288/1970,14.6 %, colonoscopy: 7544/50,975,14.8 %; p = 0.55). Adverse event rates were similar in both groups (CTC: 20/2947 = 1.2 %; colonoscopy: 683/64,312 = 1.1 %), but generally less serious with CTC. CONCLUSIONS: Even though CTC was reserved for individuals either unsuitable for or unable to complete colonoscopy, we found only small differences in test-related discomfort. CTC was well tolerated as a completion procedure and was extremely safe. CTC can be delivered across a national screening programme with high patient satisfaction. KEY POINTS: • High patient satisfaction at CTC is deliverable across a national screening programme. • Patients who cannot tolerate screening colonoscopy are likely to find CTC acceptable. • CTC is extremely safe; complications are rare and almost never serious. • Patients may require more detailed information regarding the expected discomfort of CTC.

Volumetric analysis of colonic distention according to patient position at CT colonography: diagnostic value of the right lateral decubitus series.

OBJECTIVE: The purpose of this study was to compare total colonic gas volume and segmental luminal distention according to patient position on CT colonography (CTC), as well as to determine which two views should constitute the routine protocol. MATERIALS AND METHODS: Volumetric analysis was retrospectively performed on CTC examinations from 146 adults (mean age, 59.2 years; 81 men and 65 women; mean body mass index [BMI], 30.9) for whom supine, prone, and right lateral decubitus series were sequentially obtained using continuous low-pressure CO2 insufflation. Total colonic gas volumes were assessed using a novel automated volumetric tool. In addition, two radiologists scored distention by segment using a 4-point scale (4=optimal; 3=adequate; 2=inadequate; 1=collapsed). RESULTS: Mean (±SD) colonic gas volumes for supine, prone, and decubitus positioning were 1617±567, 1441±505, and 1901±627, respectively (p<0.001). Colonic volume was highest on the right lateral decubitus series in 73.3% (107/146) and lowest in 6.2% (9/146) of cases, whereas the prone series was highest in 0.7% (1/146) and lowest in 73.3% (107/146) of cases. Overall mean segmental reader scores and percentages of inadequate or collapsed for supine, prone, and decubitus positions were 3.48, 3.33, and 3.71 and 10.4%, 12.1%, and 4.2%, respectively (p<0.001). The only mean segmental scores below 3.0 were the sigmoid colon on supine (2.68) and prone (2.58) series, compared with 3.23 on decubitus series (p<0.001). Improvement in distention in both decubitus and supine positions over the prone position increased further with increasing BMI (p<0.001). CONCLUSION: The right lateral decubitus position consistently yields the best colonic distention at CTC and significantly improves evaluation of the sigmoid colon. Prone distention was the worst, particularly as BMI increased. Routine supine and decubitus positioning should be considered for standard CTC protocols, particularly in obese individuals. Automated volumetric analysis provides for rapid objective assessment of colonic distention.

A Survey on Machine Learning and Deep Learning-based Computer-Aided Methods for Detection of Polyps in CT Colonography.

BACKGROUND: Colon cancer generally begins as a neoplastic growth of tissue, called polyps, originating from the inner lining of the colon wall. Most colon polyps are considered harmless but over the time, they can evolve into colon cancer, which, when diagnosed in later stages, is often fatal. Hence, time is of the essence in the early detection of polyps and the prevention of colon cancer. METHODS: To aid this endeavor, many computer-aided methods have been developed, which use a wide array of techniques to detect, localize and segment polyps from CT Colonography images. In this paper, a comprehensive state-of-the-art method is proposed and categorize this work broadly using the available classification techniques using Machine Learning and Deep Learning. CONCLUSION: The performance of each of the proposed approach is analyzed with existing methods and also how they can be used to tackle the timely and accurate detection of colon polyps.