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BACKGROUND AND AIMS: Water exchange (WE) and cap-assisted colonoscopy separately have been shown to reduce pain during insertion in unsedated patients. We hypothesized that compared with WE, WE cap-assisted colonoscopy (WECAC) could significantly lower real-time maximum insertion pain (RTMIP). METHODS: Veterans without escort were recruited, randomized, blinded, and examined at 3 U.S. Veterans Affairs sites. The primary outcome was RTMIP, defined as the highest segmental pain (0 = no pain, 10 = most severe pain) during insertion. RESULTS: Randomization (WECAC, 143; WE, 137) produced an even distribution of a racially diverse group of men and women of low socioeconomic status. The intention-to-treat analysis reported results of WECAC and WE for cecal intubation (93% and 94.2%, respectively), mean RTMIP (2.9 [standard deviation {SD}, 2.5] and 2.6 [SD, 2.4]), proportion of patients with no pain (28.7% and 27.7%), mean insertion time (18.6 minutes [SD, 15.6] and 18.8 minutes [SD, 15.9]), and overall adenoma detection rate (48.3% and 55.1%); all P values were >.05. When RTMIP was binarized as "no pain" (0) versus "some pain" (1-10) or "low pain" (0-7) versus "high pain" (8-10), different significant predictors of RTMIP were identified. CONCLUSIONS: Unsedated colonoscopy was appropriate for unescorted veterans. WE alone was sufficient. Adding a cap did not reduce RTMIP. Patient-specific factors and application of WE with insertion suction of infused water contributed to high and low RTMIP, respectively. For unescorted patients, selecting those with low anxiety, avoiding low body mass index, history of depression or self-reported poor health, and complying with the steps of WE can minimize RTMIP to ensure success of unsedated colonoscopy. (Clinical trial registration number: NCT03160859.).
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OBJECTIVES: Increased iron deposition in the brain may occur in several neurodegenerative diseases, including Alzheimer disease (AD). Iron deposits shorten T2 relaxation times on T2-weighted magnetic resonance (MR) images. Iron-dependent contrast increases with magnetic field strength. We hypothesized that T2 mapping using 3 T MR imaging (MRI) can disclose differences between normal controls and AD subjects. METHODS: High-resolution brain imaging protocols were developed and applied to 24 AD patients and 20 age-matched controls using 3 T MRI. Eight anatomical regions of interest were manually segmented, and T2 histograms were computed. A visual analysis technique, the heat map, was modified and applied to the large image data sets generated by these protocols. RESULTS: A large number (163) of features from these histograms were examined, and 38 of these were significantly different (P < 0.05) between the groups. In the hippocampus, evidence was found for AD-related increases in iron deposition (shortened T2) and in the concentration of free tissue water (lengthened T2). Imaging of a section of postmortem brain before and after chemically extracting the iron established the presence of MRI-detectable iron in the hippocampus, cortex, and white matter in addition to brain regions traditionally viewed as containing high iron concentrations.