Computed tomographic colonography: how many and how fast should radiologists report?

Single CT Appointment for Double Lung and Colorectal Cancer Screening: Is the Time Ripe?

Annual screening of lung cancer (LC) with chest low-dose computed tomography (CT) and screening of colorectal cancer (CRC) with CT colonography every 5 years are recommended by the United States Prevention Service Task Force. We review epidemiological and pathological data on LC and CRC, and the features of screening chest low-dose CT and CT colonography comprising execution, reading, radiation exposure and harm, and the cost effectiveness of the two CT screening interventions. The possibility of combining chest low-dose CT and CT colonography examinations for double LC and CRC screening in a single CT appointment is then addressed. We demonstrate how this approach appears feasible and is already reasonable as an opportunistic screening intervention in 50–75-year-old subjects with smoking history and average CRC risk. In addition to the crucial role Computer Assisted Diagnosis systems play in decreasing the test reading times and the need to educate radiologists in screening chest LDCT and CT colonography, in view of a single CT appointment for double screening, the following uncertainties need to be solved: (1) the schedule of the screening CT; (2) the effectiveness of iterative reconstruction and deep learning algorithms affording an ultra-low-dose CT acquisition technique and (3) management of incidental findings. Resolving these issues will imply new cost-effectiveness analyses for LC screening with chest low dose CT and for CRC screening with CT colonography and, especially, for the double LC and CRC screening with a single-appointment CT.

Meeting the new joint British Society of Gastrointestinal and Abdominal Radiology and Royal College of Radiologists CT colonography standards: a 6-year experience

AIM

To audit the performance of computed tomography colonography (CTC) at St Mark's Hospital against the joint British Society of Gastrointestinal and Abdominal Radiology (BSGAR) and Royal College of Radiologists (RCR) standards.

MATERIALS AND METHODS

A retrospective audit of all CTC studies between January 2012 to December 2017 was performed against the BSGAR/RCR standards along with additional data outwith the guidelines. Evidence was obtained from a central database, radiology information systems (RISs), picture archiving and communication systems (PACSs), and electronic patient records (EPRs).

RESULTS

Over the 6 years, 13,143 CTCs were performed and 12,996 (99%) were adequate or better. Of the cases 1,867 had a >6 mm polyp or cancer reported (polyp identification rate [PIR] 14%) and the positive predictive value (PPV) was 93% (1,148/1,240). Median radiation dose was 458 mGy·cm, mean additional acquisition rate was 19% (2,505/13,143), subsequent endoscopy rate was 9% (1,222/13,143) and mean interpretation time for a negative study was 34.6 minutes. Nine perforations occurred (perforation rate of 0.068%) and one was symptomatic (symptomatic perforation rate of 0.008%). For suspected cancers, the same-day endoscopy rate was 27% (96/360) and same-day staging rate was 76% (272/360). Post-imaging colorectal cancer rates (PICRC) was 3.06 per 100 cancers detected and 0.23 per 1,000 CTCs. The service was always rated "good" or higher by patients.

CONCLUSION

This audit shows the CTC service at St Mark's Hospital to be safe and of sufficiently high quality to meet the BSGAR/RCR standards with most outcomes equal to or above the aspirational target. Areas for service and individual reader improvement were also identified.

Re-initiation of CT colonography services during the COVID-19 pandemic: Preliminary evaluation of safety

Objective:

The COVID-19 pandemic has led to cancellation and deferral of many cancer investigations, including CT colonography (CTC). In May 2020, BSGAR and SCoR issued guidelines outlining steps for conduct of CTC in the early recovery phase. We evaluated the implementation of these in four English hospital trusts.

Methods:

Ethical permission was not required for this multicentre service evaluation. We identified patients undergoing CTC over a 2-month period from May to July 2020 at four Trusts. We recorded demographics, scan indications, colonic findings, and incidental lung base changes compatible with COVID-19. A subset of patients were contacted via telephone to document new symptoms 2 weeks following their scan. Staff were contacted to determine if any acquired COVID-19 during the period.

Results:

224 patients (118 male, 52.7%) were scanned during the period. In 55 patients (24.6%), CTC showed a ≥6 mm polyp. 33 of 224 (14.7%) scans showed incidental lung base changes felt unrelated to COVID-19, and only one patient had changes indeterminate for COVID-19; no classic COVID-19 pulmonary changes were found. Of 169 patients with telephone follow-up, none reported any new symptoms of COVID-19 (cough, fever, anosmia, ageusia) within 14 days of CTC. None of the 86 staff contacted developed COVID-19.

Conclusion:

We found no cases of patients or staff acquiring COVID-19 infection following CTC; and no evidence of significant asymptomatic COVID-19 patients attending for CTC appointments based on lung base changes.

Advances in knowledge:

Our findings suggest that current practice is unlikely to contribute significantly to spread of SARS-nCOV2. Cancer and significant polyp detection rates were high, underlining the importance of maintaining service provision.