Measurement of skeletal muscle perfusion during postischemic reactive hyperemia using contrast-enhanced MRI with a step-input function
✍ Scribed by Richard B. Thompson; Ronnier J. Aviles; Anthony Z. Faranesh; Venkatesh K. Raman; Victor Wright; Robert S. Balaban; Elliot R. McVeigh; Robert J. Lederman
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 544 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
The regional distribution of skeletal muscle blood flow was measured during postischemic reactive hyperemia using Gd‐DTPA contrast‐enhanced (CE) MRI. The release of an occlusive thigh cuff was used to deliver a step‐input of contrast concentration that was coincident with the onset of reactive hyperemia. A first‐order tracer kinetic equation was used to estimate the unidirectional influx constant, K~i~ (ml/100 g/min), and the distribution volume of Gd‐DTPA in the tissue, v~e~, from T~1~‐weighted images acquired with saturation recovery (SR) steady‐state free precession (SSFP) and spoiled gradient‐echo (SPGR) protocols. The capillary permeability surface (PS) area increased significantly during reactive hyperemia, which facilitated rapid extraction of Gd‐DTPA during the first pass. Regional muscle group studies from 11 normal volunteers yielded blood flow (K~i~) values of 108.3 ± 34.1 ml/100 g/min in the gastrocnemius, 184.3 ± 41.3 ml/100 g/min in the soleus, and 122.4 ± 34.4 ml/100 g/min in the tibialis anterior. The distribution volumes (v~e~) in the corresponding muscle groups were respectively 8.3% ± 2.1%, 9.3% ± 1.9%, and 7.9% ± 1.8% from the kinetic model, and 8.8% ± 2.4%, 9.1% ± 1.9%, and 7.2% ± 1.4% from tissue relaxometry studies. Bulk blood flow studies in the same volunteers using phase‐contrast velocimetry (popliteal artery) yielded significantly lower flow values, but with a correlation coefficient R~2~ = 0.62 and P = 0.004. Magn Reson Med 54:289–298, 2005. Published 2005 Wiley‐Liss, Inc.