No abstract

Muscle blood flow (MBF) and muscle oxygen saturation (SmO(2)) were measured at eight locations (four proximal, four distal) over a 4 x 8 cm(2) area of the vastus lateralis at rest and immediately after isometric, maximal quadriceps contraction using multichannel, frequency-domain, near-infrared spectroscopy. A venous occlusion was applied 20 s before the end of the exercise, so that the venous-occlusion-induced increase in total hemoglobin was recorded without any delay after the end of the exercise. Therefore, we were able to investigate the relationship between the exercise-induced changes in vastus lateralis MBF and SmO(2). After exercise, MBF increased significantly at each measured location. Comparing the MBF values measured at the end of exercise in the proximal and distal regions, we observed that only one proximal region had a significantly higher MBF than the corresponding distal one. The maximum desaturation measured during exercise was positively correlated with the postexercise to pre-exercise MBF ratio in both the proximal (P=0.016) and distal (P=0.0065) regions. These data confirm that frequency-domain tissue oximeters are noninvasive, powerful tools to investigate the spatial and temporal features of muscle blood flow and oxygenation, with potential applications in areas of pathophysiology.

The intrauterine device (IUD) is gaining popularity as a reversible form of contraception. Ultrasonography serves as first-line imaging for the evaluation of IUD position in patients with pelvic pain, abnormal bleeding, or absent retrieval strings. This review highlights the imaging of both properly positioned and malpositioned IUDs. The problems associated with malpositioned IUDs include expulsion, displacement, embedment, and perforation. Management considerations depend on the severity of the malposition and the presence or absence of symptoms. Three-dimensional ultrasonography has proven to be more sensitive in the evaluation of more subtle findings of malposition, particularly side-arm embedment. Familiarity with the ultrasonographic features of properly positioned and malpositioned IUDs is essential.