Pathophysiology, diagnosis, and management of opioid-induced constipation.

Opioids are potent analgesics used for the treatment of acute and chronic pain. Side-effects are common and among the most bothersome are those associated with opioid-induced bowel dysfunction, which includes opioid-induced constipation. In this Review, we provide a summary of the pathophysiology, diagnosis, and management of opioid-induced constipation, which can be defined as a change in baseline bowel habit or defecatory patterns following initiation, alteration, or increase of opioid therapy. Opioid-induced constipation is a consequence of the action of opioids on their receptors in the gastrointestinal tract. A comprehensive clinical assessment is beneficial, including evaluation of the patient's understanding of their constipation and underlying condition for which opioids are used. Clinical assessment should also aim to differentiate opioid-induced constipation from pre-existing constipation exacerbated by the opioids. Preventive strategies need to be considered when patients start treatment with opioids, such as lifestyle changes. First-line management includes simple over-the-counter laxatives. The bowel function index can be useful to objectively identify patients who are refractory to these initial measures. In this context, alternative over-the-counter laxatives (or combinations of laxatives), secretogogues, or peripherally acting µ-opioid receptor antagonists might also be considered. Educational strategies need to be developed to improve the knowledge base of health-care providers on the identification and management of opioid-induced constipation.

Synchrotron based planar imaging and digital tomosynthesis of breast and biopsy phantoms using a CMOS active pixel sensor.

The SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at Elettra is performing the first mammography study on human patients using free-space propagation phase contrast imaging. The stricter spatial resolution requirements of this method currently force the use of conventional films or specialized computed radiography (CR) systems. This also prevents the implementation of three-dimensional (3D) approaches. This paper explores the use of an X-ray detector based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology as a possible alternative, for acquisitions both in planar and tomosynthesis geometry. Results indicate higher quality of the images acquired with the synchrotron set-up in both geometries. This improvement can be partly ascribed to the use of parallel, collimated and monochromatic synchrotron radiation (resulting in scatter rejection, no penumbra-induced blurring and optimized X-ray energy), and partly to phase contrast effects. Even though the pixel size of the used detector is still too large - and thus suboptimal - for free-space propagation phase contrast imaging, a degree of phase-induced edge enhancement can clearly be observed in the images.

A novel approach to digital breast tomosynthesis for simultaneous acquisition of 2D and 3D images.

OBJECTIVE: The complexity of anatomical structure within the breast represents the ultimate limit to signal detection on a mammogram. To increase lesion conspicuity Digital Breast Tomosynthesis (DBT) has been recently proposed and several manufacturers are currently performing clinical trials. In this study we investigate the potential of DBT with variable dose distribution by using a phantom in which details of interest are within a heterogeneous background. METHODS: To compare the performance of a commercial digital mammography unit and a DBT prototype, 2D and 3D images of the breast phantom were obtained at similar dose levels. RESULTS: As expected, DBT showed superior performance over digital mammography. Although certain details of interest are not detectable with digital mammography, DBT can reveal their signal by reducing the complexity of tissue structures. Additionally, the potential of the central projection in variable dose DBT is similar to the standard projection obtained with digital mammography. Finally, the uniform and variable dose approaches provided almost identical reconstructed slices. CONCLUSION: This preliminary investigation demonstrates that breast tomosynthesis acquired with variable dose distribution exhibits inherent 3D reconstruction advantages for structure noise removal and provides a 2D projection with a physical image quality close to that of standard mammography.

Multidirectional pelvic floor muscle strength measurement.

Pelvic floor muscle (PFM) strength measurement provides useful information for the study of pelvic floor dysfunctions. Vaginal digital palpation, intravaginal pressure measurements, and the use of a dynamometric speculum represent currently available clinical methods for evaluating PFM strength. However, none of these methods provide a dynamic measurement of pelvic floor strength in multiple directions simultaneously. The aim of the present paper is to report the development and first measurement trial of a device that follows the vaginal canal morphology and is able to measure pelvic floor strength multidirectionally.