Extracolonic findings at CT colonography: a review of 258 consecutive cases

ACR Appropriateness Criteria® Colorectal Cancer Screening

This review summarizes the relevant literature regarding colorectal screening with imaging. For individuals at average or moderate risk for colorectal cancer, CT colonography is usually appropriate for colorectal cancer screening. After positive results on a fecal occult blood test or immunohistochemical test, CT colonography is usually appropriate for colorectal cancer detection. For individuals at high risk for colorectal cancer (eg, hereditary nonpolyposis colorectal cancer, ulcerative colitis, or Crohn colitis), optical colonoscopy is preferred because of its ability to obtain biopsies to detect dysplasia. After incomplete colonoscopy, CT colonography is usually appropriate for colorectal cancer screening for individuals at average, moderate, or high risk. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A comparison of computer-assisted detection (CAD) programs for the identification of colorectal polyps: performance and sensitivity analysis, current limitations and practical tips for radiologists

AIM

To directly compare the accuracy and speed of analysis of two commercially available computer-assisted detection (CAD) programs in detecting colorectal polyps.

MATERIALS AND METHOD

In this retrospective single-centre study, patients who had colorectal polyps identified on computed tomography colonography (CTC) and subsequent lower gastrointestinal endoscopy, were analysed using two commercially available CAD programs (CAD1 and CAD2). Results were compared against endoscopy to ascertain sensitivity and positive predictive value (PPV) for colorectal polyps. Time taken for CAD analysis was also calculated.

RESULTS

CAD1 demonstrated a sensitivity of 89.8%, PPV of 17.6% and mean analysis time of 125.8 seconds. CAD2 demonstrated a sensitivity of 75.5%, PPV of 44.0% and mean analysis time of 84.6 seconds.

CONCLUSION

The sensitivity and PPV for colorectal polyps and CAD analysis times can vary widely between current commercially available CAD programs. There is still room for improvement. Generally, there is a trade-off between sensitivity and PPV, and so further developments should aim to optimise both. Information on these factors should be made routinely available, so that an informed choice on their use can be made. This information could also potentially influence the radiologist's use of CAD results.

Lumbar Transforaminal Epidural Steroid Injections: Incidental Extraspinal Findings on Planning Imaging

OBJECTIVE

Planning imaging performed during CT-guided procedures may occasionally contain important incidental findings. The purpose of this study was to identify and characterize by clinical relevance the extraspinal findings detected on planning imaging for CT-guided lumbar transforaminal epidural steroid injections (TFESIs).

MATERIALS AND METHODS

Four radiologists retrospectively evaluated the planning scout views and CT studies for 488 consecutive CT-guided lumbar TFESIs performed in 400 patients over a 1-year period. Incidental extraspinal findings were identified and used to characterize patients by the need for follow-up using the CT Colonography Reporting and Data System (C-RADS), a classification scheme originally developed to characterize incidental findings on CT colonography. Patients with C-RADS E4 findings have potentially important findings that should be communicated to the referring physician; patients with C-RADS E3 findings have findings that are likely unimportant, but workup may be indicated. All previously unknown C-RADS E3 and E4 findings discovered in the course of this research were reported to referring physicians for appropriate patient follow-up.

RESULTS

Ten of 400 (2.5%) patients were classified as C-RADS E4; the most common C-RADS E4 finding was vascular aneurysm or stenosis (4/400, 1.0%). Thirteen of 400 (3.3%) patients were classified as C-RADS E3; the most common C-RADS E3 finding was hepatomegaly (4/400, 1.0%). Of 22 patients with C-RADS E3 and E4 findings unknown to clinicians, the finding for only one (4.5%) was communicated to clinicians at the time of the procedure.

CONCLUSION

Clinically important incidental extraspinal findings were identified in 5.8% of patients on the planning imaging performed for CT-guided lumbar TFESIs. Communication of clinically important findings was poor (4.5%).

Indeterminate but Likely Unimportant Extracolonic Findings at Screening CT Colonography (C-RADS Category E3): Incidence and Outcomes Data From a Clinical Screening Program

OBJECTIVE

The purpose of this study was to analyze the incidence and outcomes of unsuspected indeterminate but likely unimportant extracolonic findings (CT Colonography Reporting and Data System [C-RADS] category E3) at screening CT colonography (CTC).

MATERIALS AND METHODS

Over 99 months (April 2004 through June 2012), 7952 consecutive adults without symptoms of colorectal cancer (4277 women, 3675 men; mean age ± SD, 56.7 ± 7.3 years) underwent first-time screening CTC. Findings prospectively placed into C-RADS category E3 were retrospectively reviewed, including follow-up (range, 2-10 years) and ultimate clinical outcome.

RESULTS

Unsuspected C-RADS category E3 extracolonic findings were detected in 9.1% (725/7952) of our patient population. A total of 751 category E3 findings were detected among these 725 patients; 25 patients had multiple findings. Commonly involved organ systems included gynecologic (24.4%, 183/751), genitourinary (20.9%, 157/751), lung (20.6%, 155/751), and gastrointestinal (16.1%, 121/751). Consideration for further imaging, if clinically warranted, was suggested in 83.8% (608/725). Sixty-five patients were lost to follow-up. Conditions requiring treatment or surveillance were ultimately diagnosed in 8.3% (55/660), including eight malignant neoplasms. In the remaining 605 patients, 25 (4.1%) underwent invasive biopsy or surgery to prove benignity (including 18 complex adnexal masses), and 278 (46.0%) received additional imaging follow-up.

CONCLUSION

Indeterminate but likely unimportant extracolonic findings (C-RADS category E3) occurred in less than 10% of adults without symptoms of colorectal cancer who underwent screening CTC. Over 90% of these findings ultimately proved to be clinically insignificant, with fewer than 5% requiring an invasive procedure to prove benign disease, the majority of which (> 70%) were complex adnexal lesions in women.

Potentially Important Extracolonic Findings at Screening CT Colonography: Incidence and Outcomes Data From a Clinical Screening Program

OBJECTIVE

The effect of detection of extracolonic findings at screening CT colonography (CTC) remains controversial. Our objective is to analyze the incidence and outcomes of unsuspected potentially significant (CT Colonography Reporting and Data System [C-RADS] extracolonic category E4) findings in a population undergoing clinical CTC screening.

SUBJECTS AND METHODS

Over the course of 99 months (April 1, 2004, through June 30, 2012), 7952 consecutive asymptomatic adults (3675 men and 4277 women; mean [± SD] age, 56.7 ± 7.3 years) underwent first-time screening CTC. Examinations were prospectively interpreted by radiologists within our abdominal imaging section, and extracolonic findings were recorded and categorized. Potentially significant (i.e., C-RADS extracolonic category E4) findings were retrospectively reviewed with additional analysis of follow-up (range, 2-10 years) and ultimate clinical outcome.

RESULTS

Overall, 2.5% (202/7952) of patients had a potentially significant (C-RADS category E4) extracolonic finding for which further imaging (56%; 113/202) or clinical follow-up (44%; 89/202) was recommended. No patients had multiple category E4 findings. Twenty-two patients were lost to follow-up. Of the remaining 180 patients, 68% (123/180) proved to have clinically significant disease, including 23% (42/180) with malignant or potentially malignant neoplasms and 32% (57/180) with abdominal aortic or other visceral artery aneurysms requiring treatment or surveillance. The most commonly involved organs and systems included the vascular system (26%; 53/202), the genitourinary system (18%; 36/202), the liver (15%; 30/202), the gastrointestinal system (9.9%; 20/202), the lungs (9.4%; 19/202), and the gynecologic system (6.9%; 14/202).

CONCLUSION

Potentially significant extracolonic findings in asymptomatic adults at screening CTC are uncommon (2-3% of cases). However, most of these findings (68%) will prove to be clinically significant, including a number of malignancies and aneurysms requiring treatment or surveillance.

Computed tomographic colonography is valuable for post-treatment evaluation and screening of hidden colorectal cancer in patients with cryptogenic pyogenic liver abscess

BACKGROUND/AIMS

It has been demonstrated that cryptogenic pyogenic liver abscess (PLA) is associated with colonic mucosal defect, especially colorectal cancer (CRC). Therefore, the screening of CRC in patients with cryptogenic PLA is important. This study was to investigate whether computed tomographic colonography (CTC) has value as a follow-up modality as well as CRC screening tool in patients with PLA.

METHODS

A retrospective evaluation of 109 patients with cryptogenic PLA who underwent CTC or colonoscopy for CRC screening between July 2005 and July 2012 was performed. The patients were divided into a CTC group (n = 68) and colonoscopy group (n = 41) after treatment of liver abscess, and compared concerning the detection rate of advanced neoplasia, consisting of advanced adenomas and invasive carcinomas. Patients with advanced polyps in CTC surveillance underwent subsequent colonoscopy.

RESULTS

Advanced colonic neoplasia was detected in 9 of the 68 patients (13.2%) in the CTC group and 8 of the 41 patients (19.5%) in the conventional colonoscopy group (p = 0.42). The treatment response of all abscess lesions was clearly visualized on CTC, with complete resolution in 17.6% (12/68) of patients. After adjustment for sex and pathogens, old age (≥65 years) was significantly associated with advanced neoplasia (OR 5.481; 95% CI 1.757-17.100; p = 0.03).

CONCLUSION

CTC has a valuable dual role as a follow-up modality and in the screening of CRC in patients with cryptogenic PLA, particularly in elderly patients over 65 years of age.

ACR Appropriateness Criteria colorectal cancer screening

Colorectal cancer is the third leading cause of cancer deaths in the United States. Most colorectal cancers can be prevented by detecting and removing the precursor adenomatous polyp. Individual risk factors for the development of colorectal cancer will influence the particular choice of screening tool. CT colonography (CTC) is the primary imaging test for colorectal cancer screening in average-risk individuals, whereas the double-contrast barium enema (DCBE) is now considered to be a test that may be appropriate, particularly in settings where CTC is unavailable. Single-contrast barium enema has a lower performance profile and is indicated for screening only when CTC and DCBE are not available. CTC is also the preferred test for colon evaluation following an incomplete colonoscopy. Imaging tests including CTC and DCBE are not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the updated colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Competition in Colon Cancer Screening? What Is the Role of Colonoscopy?

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the Western world. The incidence could be reduced if this cancer were to be diagnosed at an early stage of disease. A competition has started between the existing screening methods to be the most efficient in detecting premalignant conditions. This review illustrates the current state of screening techniques for CRC.

METHOD

Pubmed was searched for meta-analyses and prospective studies on screening for CRC, with an emphasis on colonography, computed tomographic colonography (CTC), magnetic resonance colonography (MRC), stool DNA testing, and colon capsule endoscopy, and critical appraisal of the research was done by the reviewers.

RESULTS

The imaging techniques (CTC and MRC) had similar detection rates for bigger lesions (≥10 mm) as colonoscopy. High-definition colonoscopy showed better efficiency with smaller lesions. The techniques developing around colonoscopy such as the retro-viewing colonoscope, the balloon colonoscope, or the 330-degree viewing colonoscope try to enhance efficacy by reducing the adenoma miss rate in right-sided, non-polypoid lesions. Colon capsule endoscopy and the stool detection systems are limited to identifying cancer but not necessarily adenomas.

CONCLUSION

Colonoscopy is the preferred CRC screening strategy and the undisputed gold standard in terms of efficacy.

Extracolonic findings (ECF) on CT colonography (CTC) in patients presenting with colorectal symptoms

BACKGROUND

Computed tomographic colonography (CTC) is now an established method for imaging the colon and rectum in the screening and symptomatic setting. Additional benefit of CTC is the ability to assess for extracolonic findings especially in patients presenting with colorectal symptoms.

PURPOSE

To determine prevalence of extracolonic findings (ECF) in symptomatic patients undergoing CTC and determine accuracy of CTC for exclusion of significant abdominal disease and extracolonic malignancy (ECM).

MATERIAL AND METHODS

A total of 1359 unenhanced prone and postcontrast supine CTC studies were performed between March 2002 and December 2007. ECF were retrospectively classified according to C-RADS criteria into E1 to E4 findings. For ECM, a gold standard of clinical and/or radiological follow-up supplemented with data from the regional cancer registry with a median follow-up of 42 months was created. Sensitivity and negative predictive values for ECM was calculated.

RESULTS

Following exclusions, 1177 CTCs were analyzed. Of 1423 extracolonic findings reported, 328/1423 (23%) E3 and 100/1423 (7%) E4 (including six eventual FP studies) findings were identified. Thirty-two ECMs were confirmed following further investigations. Seven further small ECMs were detected during the entire follow-up, of which two were potentially visible in retrospect (false-negative studies). Additional tests were generated from 55/1177 (4.7%) studies. Sensitivity and negative predictive value for ECM was 94.1% (95% CI 78.9-98.9%) and 99.8% (95% CI 99.3-99.9%), respectively.

CONCLUSION

One in 37 patients were found to have an ECM. Two potentially detectable cancers were missed. Only a small proportion of patients underwent additional work-up.

The time has arrived for national reimbursement of screening CT colonography

OBJECTIVE

CT colonography (CTC) has been fully validated as an accurate screening test for colorectal carcinoma and is being disseminated globally. There is an abundance of new literature addressing the prior concerns of the U.S. Preventive Services Task Force and the Centers for Medicare & Medicaid Services. Specific areas related to radiation dose, extracolonic findings, and generalizability of CTC to senior patients are discussed.

CONCLUSION

The time has arrived for national reimbursement of CTC in the United States.

Advances in CT Colonography for Colorectal Cancer Screening and Diagnosis

CT colonography (CTC) is a validated colorectal cancer test that provides an additional minimally-invasive screening option which is likely to be preferred by some patients. Important examination prerequisites include adequate colonic cleansing and distention. Tagging of residual material aids in the differentiation of true polyps from stool. Low radiation dose technique should be employed routinely for screening studies. Readers must be skilled in the use of both 2D and 3D interpretation methods.

Screening for colorectal cancer: what fits best?

Colorectal cancer (CRC) screening has been shown to be effective in reducing CRC incidence and mortality. There are currently a number of screening modalities available for implementation into a population-based CRC screening program. Each screening method offers different strengths but also possesses its own limitations as a population-based screening strategy. We review the current evidence base for accepted CRC screening tools and evaluate their merits alongside their challenges in fulfilling their role in the detection of CRC. We also aim to provide an outlook on the demands of a low-risk population-based CRC screening program with a view to providing insight as to which modality would best suit current and future needs.