Ischemia‐reperfusion injury in rat skeletal muscle assessed with T₂‐weighted and dynamic contrast‐enhanced MRI

Abstract

Pressure ulcers are localized areas of soft tissue breakdown due to mechanical loading. Susceptible individuals are subjected to pressure relief strategies to prevent long loading periods. Therefore, ischemia-reperfusion injury may play an important role in the etiology of pressure ulcers. To investigate the inter-relation between postischemic perfusion and changes in skeletal muscle integrity, the hindlimbs of Brown Norway rats were subjected to 4-h ischemia followed by 2-h reperfusion. Dynamic contrastenhanced MRI was used to examine perfusion, and changes in skeletal muscle integrity were monitored with T 2 -weighted MRI. The dynamic contrast-enhanced MRI data showed a heterogeneous postischemic profile in the hindlimb, consisting of areas with increased contrast enhancement (14-76% of the hindlimb) and regions with no-reflow (5-77%). For T 2 , a gradual increase in the complete leg was observed during the 4-h ischemic period (from 34 to 41 msec). During the reperfusion phase, a heterogeneous distribution of T 2 was observed. Areas with increased contrast enhancement were associated with a decrease in T 2 (to 38 msec) toward preischemic levels, whereas no-reflow areas exhibited a further increase in T 2 (to 42 msec). These results show that reperfusion after prolonged ischemia may not be complete, thereby continuing the ischemic condition and aggravating tissue damage. Magn Reson Med 66:528-537, 2011.

Skeletal muscle evaluation by MRI in a rabbit model of acute ischaemia

“…We observed a similar phenomenon and hence both the ROI analysis and the biopsy were obtained in the vastus lateralis muscle [28].…”

A MRI-Compatible Combined Mechanical Loading and MR Elastography Setup to Study Deformation-Induced Skeletal Muscle Damage in Rats

“…This well-established animal model of deep tissue injury involves the compression of the rat Tibialis Anterior (TA) muscle with a custom loading device that can be placed in an MRI scanner for imaging during the development of the wound [24]. Maps of the global transversal relaxation time T 2 were used as a readout of muscle edema as a consequence of damage and inflammation after load release[23,26,31,33]. T 2 is generally accepted as quantitative damage marker in musculoskeletal MRI [34–39].…”

Magnetic Resonance Imaging at 7T Reveals Common Events in Age-Related Sarcopenia and in the Homeostatic Response to Muscle Sterile Injury

“…increase during regenerative phases was described [3]. An increased signal in T2-weighted images linked to T2 relaxation-time (T2-rt) lengthening is a commonly accepted MRI sign of muscle damage, which is supposed to reflect heterogeneous phenomena as muscle edema, inflammation and necrosis [4], [5], [6], [7], [8].…”