Contrast agent derived determination of the total circulating blood volume using magnetic resonance

Abstract

This work introduces a novel method for the determination of the total circulating blood volume using magnetic resonance contrast agents as tracers.

Blood volume measurement using cardiovascular magnetic resonance and ferumoxytol: preclinical validation

“…Two successive imaging sessions tested the repeatability of the blood volume measurement at euvolemia. Based on a target post-contrast T 1 of approximately 300 ms for optimal accuracy and precision in the T 1 measurement [ 11 ], animals received 0.7 mg/kg (0.011 mM/kg) ferumoxytol diluted in 50 ml saline infused slowly ~ 0.4 ml/sec. As ferumoxytol elimination from the blood is faster at lower concentrations [ 19 ], each animal was imaged for an hour to characterize the resultant change in T 1 .…”

“…3 . As posited by Pannek et al for Gd-based agents, V plasma can then be calculated by fitting the estimated ‘time-dependent’ plasma volume, V ′ ( t ) [ 11 ], assuming an exponential elimination: where τ is the time constant for extraction of ferumoxytol from circulation. As physiology is typically reported in terms of half-life, this term shall be reported, with the half-life t 1/2 = τ × ln 2.…”

“…A single baseline T 1 measurement was used for simulated and in vivo data. Protocol #1 (1 post-contrast T 1 measurement) represents the simplest scheme in which a single T 1 measurement at 4 min post-contrast is used to estimate blood volume (similar to Pannek, et al [ 11 ]). V blood is determined directly from Eq.…”

“…Current methods to measure blood volume include controlled inhalation of carbon monoxide to tag circulating hemoglobin, or tracer dilution using Evans blue dye or radiopharmaceuticals [ 4 , 7 – 10 ], and are infrequently used clinically because of ionizing radiation, cost, and/or complexity in stand-alone examinations. Cardiovascular magnetic resonance (CMR) dilution measurement of plasma blood volume has been attempted in rats [ 11 ] using gadopentetate dimeglumine (Gd-DTPA), which has a relatively short distribution and elimination kinetics that limit measurement accuracy and feasibility. Gadofosveset trisodium, which reversibly binds plasma albumin, might be an attractive alternative because of its a longer intravascular half-life [ 12 ] except but it exhibits significant and rapid extravascular distribution, and has been withdrawn from marketing because of poor sales.…”

Automatic indicator dilution curve extraction in dynamic-contrast enhanced imaging using spectral clustering

“…Ultrasound (Wei et al 1998, Feinstein 2004, Mischi et al 2004, Wei 2012, x-ray computed tomography (Mahnken et al 2003), and magnetic resonance imaging (MRI) contrast agents (Mischi et al 2009, Oechsner et al 2009, Pannek et al 2012, Conroy et al 2015 have been proposed as indicators for cardiovascular quantifications (Mischi et al 2005). These indicators allow the application of indicator dilution methods in a minimally invasive way, as the measurement of the IDCs in the blood pool (e.g.…”