Perry J. Pickhardt

Impact of computer-aided detection on the cost-effectiveness of CT colonography.

PURPOSEnTo analyze the cost-effectiveness of adding computer-aided detection (CAD) to a computed tomographic (CT) colonography screening program and to compare it with other options of colorectal cancer (CRC) prevention.nnnMATERIALS AND METHODSnThe cost-effectiveness of screening strategies by using CT colonography with and without CAD, flexible sigmoidoscopy (FS), and optical colonoscopy were compared by using a Markov-based computer model. In the model, a hypothetical population of 100,000 persons aged 50 years underwent colorectal screening every 10 years. Baseline sensitivities for both experienced and inexperienced readers and the incremental accuracy when adding CAD were estimated from a systematic review of the literature.nnnRESULTSnAt baseline, the addition of CAD resulted in 9% and 2% increases in CRC prevention rates for inexperienced and experienced readers, respectively, when compared with CT colonography without CAD. Assuming a CAD cost of

Cost-effectiveness of upper gastrointestinal endoscopy according to the appropriateness of the indication

50 per CT colonography, the overall program costs increased by only 3%-5%, largely because of the substantial reduction in CRC-related costs. The incremental cost-effectiveness of CT colonography with CAD compared with CT colonography without CAD was

Automatic colonic polyp detection using multi-objective evolutionary techniques

8661 and

The effect of edge-preserving image smoothing on automatic colonic polyp detection for CT colonography

61,354 per life-year gained for inexperienced and experienced readers, respectively. Optical colonoscopy was not a cost-effective alternative to CT colonography with CAD performed by experienced readers, with an incremental cost-effectiveness of

Automatic procedure to distinguish colonic polyps located on fold vs. not on fold

498,668 per life-year gained. CT colonography with CAD for inexperienced readers was more clinically effective and cost-effective than FS. At analysis, sensitivity of CT colonography with CAD for polyps 6 mm or larger was the most meaningful variable.nnnCONCLUSIONnThe addition of CAD to CT colonography screening improves the CRC prevention rate, resulting in advantageous cost-effectiveness for screening.nnnSUPPLEMENTAL MATERIALnhttp://radiology.rsnajnls.org/cgi/content/full/250/2/488/DC1.

Computed Tomographic Virtual Colonoscopy Computer-Aided Polyp Detection in a Screening Population

Objective. Application of appropriate indications for upper endoscopy (EGD) should conserve limited endoscopic resources. The cost-effectiveness of current guidelines for the detection of gastro-oesophageal cancer is unknown. The aim of this study was to assess the clinical and economic impact of ASGE and EPAGE guidelines in selecting patients referred for upper endoscopy relative to the detection of gastro-oesophageal cancer. Material and methods. A decision analysis model was constructed to compare a strategy of not referring patients for EGD (with either an appropriate or inappropriate indication) with a policy of carrying out the requested EGD. Cancer prevalence in appropriate and inappropriate EGDs was estimated using a systematic review of the literature. Costs of EGD and cancer care were estimated from Medicare reimbursement data. Results. The number of appropriate and inappropriate EGDs required to detect one case of cancer was 41 and 753, respectively, and to prevent one gastro-oesophageal cancer-related death the numbers were 571 and 11,111, respectively. The incremental cost-effectiveness ratios of appropriate and inappropriate EGDs as compared to a policy of not referring patients for endoscopy were

Primary Neoplasms of the Appendix: Radiologic Spectrum of Disease with Pathologic Correlation

16,577 and

Linear Polyp Measurement at CT Colonography: In Vitro and in Vivo Comparison of Two-dimensional and Three-dimensional Displays

301,203, respectively, per life-year gained. Conclusions. For inappropriate EGD, the very low likelihood of cancer and the relatively high costs associated with this procedure argue against endoscopic referral.

Bowel Preparation for CT Colonography

Colonic polyps appear like elliptical protrusions on the inner wall of the colon. Curvature based features for colonic polyp detection have proved to be successful in several computer-aided diagnostic CT colonography (CTC) systems. Some simple thresholds are set for those features for creating initial polyp candidates, sophisticated classification scheme are then applied on these polyp candidates to reduce false positives. There are two objective functions, the number of missed polyps and false positive rate, that need to be minimized when setting those thresholds. These two objectives conflict and it is usually difficult to optimize them both by a gradient search. In this paper, we utilized a multiobjective evolutionary method, the Strength Pareto Evolutionary Algorithm (SPEA2), to optimize those thresholds. SPEA2 incorporates the concept of Pareto dominance and applies genetic techniques to evolve individual solutions to the Pareto front. The SPEA2 algorithm was applied to colon CT images from 27 patients each having a prone and a supine scan. There are 40 colonoscopically confirmed polyps resulting in 72 positive detections in CTC reading. The results obtained by SPEA2 were compared with those obtained by our old system, where an appropriate value was set for each of those thresholds by a histogram examination method. If we keep the sensitivity the same as that of our old system, the SPEA2 algorithm reduced false positive rate by 76.4% from average false positive 55.6 to 13.3 per data set. If the false positive rate is kept the same for both systems, SPEA2 increased the sensitivity by 13.1% from 53 to 61 among 72 ground truth detections.

Chapter 13 – Colonic Distention for CT Colonography

Low radiation dose requirements create relatively noisy images that contribute to high numbers of false positive detections in CAD for CT colonography. Presumably image denoising techniques such as non-linear, edge-preserving smoothing filters can improve automatic colonic polyp detection in CT colonography by reducing overall per patient false positive rates. Here, we have evaluated multiple edge-preserving smoothing filters to determine whether this is so. Prone and supine scans from 81 asymptomatic, average-risk adults with adenomatous polyps were studied with and without smoothing. FROC curves were generated to analyze CAD results. A single, clinically relevant operating point was compared between the best smoothing filter results and the unsmoothed data. Improvement in performance was observed, but the differences were not found to be statistically significant for average dose CT colonography.