Background-Blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) has been used to measure T2* changes in skeletal muscle tissue of healthy volunteers. The BOLD effect is assumed to primarily reflect changes in blood oxygenation at the tissue level. We compared the calf muscle BOLD response of patients with peripheral arterial occlusive disease (PAOD) to that of an age-matched non-PAOD group during postischemic reactive hyperemia. Methods and Results-PAOD patients (nϭ17) with symptoms of intermittent calf claudication and an age-matched non-PAOD group (nϭ11) underwent T2*-weighted single-shot multiecho planar imaging on a whole-body magnetic resonance scanner at 1.5 T. Muscle BOLD MRI of the calf was performed during reactive hyperemia provoked by a cuff-compression paradigm. T2* maps were generated with an automated fitting procedure. Maximal T2* change (⌬T2* max ) and time to peak to reach ⌬T2* max for gastrocnemius, soleus, tibial anterior, and peroneal muscle were evaluated. Compared with the non-PAOD group, patients revealed significantly lower ⌬T2* max -values, with a mean of 7.3Ϯ5.3% versus 13.1Ϯ5.6% (PϽ0.001), and significantly delayed time-to-peak values, with a mean of 109.3Ϯ79.3 versus 32.2Ϯ13.3 seconds (PϽ0.001). Conclusions-T2* time courses of the muscle BOLD MRI signal during postocclusive reactive hyperemia revealed statistically significant differences in the key parameters (⌬T2* max ; time to peak) in PAOD patients compared with age-matched non-PAOD controls.

Prolonged compression therapy after proximal deep vein thrombosis significantly reduces symptoms and may prevent post-thrombotic skin changes. Whether these findings translate to the prevention of advanced disease states with ulcerations remains unclear.

Venous thromboembolism (VTE) is common and has a high impact on morbidity, mortality, and costs of care. Although most of the patients with VTE are aged ≥65 years, there is little data about the medical outcomes in the elderly with VTE. The Swiss Cohort of Elderly Patients with VTE (SWITCO65+) is a prospective multicenter cohort study of in- and outpatients aged ≥65 years with acute VTE from all five Swiss university and four high-volume non-university hospitals. The goal is to examine which clinical and biological factors and processes of care drive short- and long-term medical outcomes, health-related quality of life, and medical resource utilization in elderly patients with acute VTE. The cohort also includes a large biobank with biological material from each participant. From September 2009 to March 2012, 1,863 elderly patients with VTE were screened and 1003 (53.8%) were enrolled in the cohort. Overall, 51.7% of patients were aged ≥75 years and 52.7% were men. By October 16, 2012, after an average follow-up time of 512 days, 799 (79.7%) patients were still actively participating. SWITCO65+ is a unique opportunity to study short- and long-term outcomes in elderly patients with VTE. The Steering Committee encourages national and international collaborative research projects related to SWITCO65+, including sharing anonymized data and biological samples.

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10101008/-/DC1.