Bharath Ambale venkatesh PhD, Presenter: Nothing to Disclose

David A. Bluemke MD, PhD, Abstract Co-Author: Research support, Siemens AG

Joao A. C. Lima MD, Abstract Co-Author: Research Grant, Toshiba Corporation

Chikara Noda, Abstract Co-Author: Nothing to Disclose

Lower-extremity hyperemic skeletal muscle perfusion and popliteal arterial flow reserve measures could be valuable for diagnosing peripheral artery disease (PAD) and evaluating treatments that promote angiogenesis and tissue regeneration.

The Patients with Intermittent Claudication Injected with ALDH Bright Cells (PACE) study is a randomized, double-blind, placebo-controlled multi-center clinical trial, to assess the clinical safety and efficacy of autologous bone marrow derived aldehyde dehydrogenase-bright cells. In a preliminary analysis of 16 PAD patiens with an ankle-brachial index <0.9 and significant stenosis in the infrainguinal arteries at baseline as part of this study, MRI-derived measures of hyperemic calf muscle perfusion from dynamic contrast-enhanced (DCE) MRI and hyperemic popliteal artery flow from phase-contrast (PC) MRI were evaluated. Scans were performed in 1.5-T and 3-T scanners (GE, Siemens and Philips) across multiple centers using 0.05 mmol/kg Magnevist, and using a 5-minute occlusion of femoral artery flow by inflating a thigh cuff to suprasystolic pressures on the asymptomatic leg to induce hyperemia. DCE-MRI was performed at 8 slices at mid-calf using 3D SPGR sequences (spatial resolution: 1x1x5 mm, temporal resolution <5ms) and was preceded by a variable flip angle method to measure T1. Semi-quantitative measures and quantitative measures were obtained from the modified Tofts’ model post-hyperemia: area under the gadolinium curve at 60s (iAUC) and fractional blood plasma volume (Vb). The arterial flow reserve (AFR) was obtained as difference in peak flow (ml/s) after and before induced hyperemia from PC-MRI.

The patients were on average 66 years, with mean Vb = 4.5±5.2%, iAUC = 1.097±0.43 mmol/L*s and AFR = 1.144±1.15 ml/s. The iAUC was correlated with the absolute AFR – r = 0.55, p=0.027. The difference in average velocity at hyperemic and resting states was correlated to both the iAUC (r=0.51, p=0.045) and Vb (r=0.6, p=0.015).

Hyperemic blood flow rates measured with PC-MRI were related with hyperemic fractional blood plasma volume and tissue contrast uptake from DCE-MRI in PAD patients.

This helps in indentification of skeletal muscle perfusion in relation to blood flow.

Ambale venkatesh, B, Bluemke, D, Lima, J, Noda, C, Hyperemic Fractional Microvascular Blood Plasma Volume Is Related to Arterial Flow Reserve in Patients with Arterial Disease.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14019736.html