When the p Value Doesn't Cut It: The Fragility Index Applied to Randomized Controlled Trials in Colorectal Surgery.

Background: The American Statistical Association, among others, has called for the use of statistical methods beyond p ≤ 0.05. The fragility index is a statistical metric defined as the minimum number of patients for whom if an event rather than a nonevent occurred, then the p value would increase to ≥0.

Imaging Modalities for Evaluation of Intestinal Obstruction.

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging.

The Acute Upper Gastrointestinal Bleed.

Upper gastrointestinal bleeding (UGIB), defined as intraluminal hemorrhage proximal to the ligament of Treitz, can range from mild and asymptomatic to massive life-threatening hemorrhage. For the purposes of this article, the authors define an acute UGIB to be one that results in new acute symptoms and is, therefore, potentially life-threatening. UGIB requires a systematic approach to evaluation and treatment, similar to the management of a trauma patient.

Assessment of three dead detector correction methods for cone-beam computed tomography.

Purpose: Dead detectors due to manufacturing defects or radiation damage in the electronic portal imaging devices (EPIDs) used for cone-beam computed tomography (CBCT) can lead to image degradation and ring artifacts. In this work three dead detector correction methods were assessed using megavoltage CBCT (MVCBCT) as a test system, with the goals of assessing the relative effectiveness of the three methods and establishing the conditions for which they fail.

Methods: MVCBCT projections acquired with four linacs at 8 and 60 MU (monitor units) were degraded with varying percentages (2%-95%) of randomly distributed dead single detectors (RDSs), randomly distributed dead detector clusters (RDCs) of 2 mm diameter, and nonrandomly distributed dead detector disks (NRDDs) of varying diameter (4-16 mm).