BOLD MRI can be used to monitor changes in intrarenal oxygenation in humans in a noninvasive fashion.

In persons with knee OA, knee pain severity was associated with subarticular bone attrition, bone marrow lesions, synovitis/effusion, and meniscal tears. The contribution of bone marrow lesions to pain severity appeared to require the presence of bone attrition.

Objective. Progressive knee osteoarthritis (OA) is believed to result from local factors acting in a systemic environment. Previous studies have not examined these factors concomitantly or compared quantitative and qualitative cartilage loss outcomes. The aim of this study was to test whether meniscal damage, meniscal extrusion, malalignment, and laxity each predicted tibiofemoral cartilage loss after controlling for the other factors.Methods. Laxity and alignment were measured at baseline in individuals with knee OA. Magnetic resonance imaging included spin-echo coronal and sagittal imaging for meniscal scoring and axial and coronal spoiled gradient echo sequences with water excitation for cartilage quantification. Tibial and weight-bearing femoral condylar subchondral bone area and cartilage surface were segmented. Cartilage volume, denuded bone area, and cartilage thickness were quantified in each plate, with progression defined as cartilage loss >2 times the coefficient of variation for each plate. Qualitative outcome was assessed as worsening of the cartilage score. Logistic regression analysis with generalized estimating equations yielded odds ratios for each factor, adjusting for age, sex, body mass index, and the other factors.Results. We studied 251 knees in 153 persons. After full adjustment, medial meniscal damage predicted medial tibial cartilage volume loss and tibial and femoral denuded bone increase, while varus malalignment predicted medial tibial cartilage volume and thickness loss and tibial and femoral denuded bone increase. Lateral meniscal damage predicted every lateral outcome. Laxity and meniscal extrusion had inconsistent effects. After full adjustment, no factor except medial laxity predicted qualitative outcome.Conclusion. Using quantitative cartilage loss assessment, local factors that independently predicted tibial and femoral loss included medial meniscal damage and varus malalignment (medially) and lateral meniscal damage (laterally). A measurement of quantitative outcome was more sensitive at revealing these relationships than a qualitative approach.Progressive knee osteoarthritis (OA) is believed to result from local mechanical factors acting in a systemic environment (1,2), although there is as yet little direct evidence of this from magnetic resonance imaging (MRI)-based natural history studies. Healthy menisci, more neutral alignment, and joint stability all protect the articular cartilage from concentrations of stress (3-5). When these factors are altered or impaired, stress is not well distributed, and it increases focally, potentially leading to articular cartilage damage. Meniscal damage, meniscal extrusion, varus-valgus malalignment, and medial-lateral laxity are local factors that may be

The effect of the oxygen inhalation on relaxation times was evaluated in various tissues, including the myocardium, liver, spleen, skeletal muscle, subcutaneous fat, bone marrow, and arterial blood, with a [1H]MR system. Statistically significant decrease of T1 relaxation times was observed in the myocardium, spleen, and arterial blood after inhalation of 100% oxygen, whereas no significant change was observed in liver, skeletal muscle, subcutaneous fat, or bone marrow. The T2 relaxation time of these tissues did not differ significantly between before and after inhalation of the oxygen. These results indicate that [1H]MRI can be used to evaluate changes with oxygen inhalation and that the effect of the oxygen inhalation on T1 relaxation time is different among various tissues.

In vivo diffusion measurements of abdominal organs obtained with MR imaging may prove helpful in the identification and classification of abdominal disease.