CONTRAST-TO-NOISE RATIO IN FUNCTIONAL MRI OF RELATIVE CEREBRAL BLOOD-VOLUME WITH SPRODIAMIDE INJECTION

The purpose of this study was to investigate the dependence of contras t-to-noise ratio (CNR) on the dose and rate of sprodiamide injection i n magnetic resonance relative cerebral blood volume [rCBV] imaging, rC BV maps for 35 normal volunteers were constructed from dynamic MR imag e sets acquired with echo-planar spin-echo imaging after intravenous i njection of sprodiamide, Doses of .1, .2, and .3 mmol/kg, at rates of 2 ml/second and 5 ml/second, were tested, CNRs and blood/volume ratios of gray to white matter were computed, CNR depended on dose [P <.0001 ] but was independent of injection rate [P <.69). rCBV ratios of gray to white matter were dose independent (P <.38) and rate independent (P <.97), The dependence of CNR on dose, but not injection rate, has pra ctical implications in optimal protocol design, The independence of gr ay/white ratios supports the theory underlying the generation of rCBV maps.