Quantitative measurement of spinal cord blood volume in humans using vascular‐space‐occupancy MRI

Abstract

Although perfusion is of major interest for many spinal cord disorders, there is no established, reproducible technique for evaluating blood flow or blood volume of the spinal cord in humans. Here the first report of in vivo measurement of human spinal cord blood volume (scBV) is presented. An FDA-approved contrast agent, Gd-DTPA, was used as an intravascular agent for the cord parenchyma, and pre-/post-contrast vascular-space-occupancy (VASO) MRI experiments were performed to obtain a quantitative estimation of scBV in mL blood/100 mL tissue. VASO MRI was used because it does not rely on knowledge of an arterial input function, it avoids the imaging artifacts of single-shot echo planar imaging approaches, and it requires only relatively simple and direct calculations for scBV quantification. Preliminary tests at 1.5 T and 3 T gave mean +/- SD scBV values of 4.3 +/- 0.7 ml/100 mL tissue (n = 6) and 4.4 +/- 0.7 ml/100 mL tissue (n = 4), respectively, consistent with the expectation that the scBV values would not be field-dependent.

Perfusion CT measurements in healthy cervical spinal cord: feasibility and repeatability of the study as well as interchangeability of the perfusion estimates using two commercially available software packages

“…Furthermore, in accordance with Hoy et al who found a plasma volume of 1 ml/100 g, which corresponds to V of 1.56 ml/100 g in dogs using radioactively labeled plasma proteins [22], we obtained a similar median value of V (about 1 ml/100 g using either an AIF in the VA or in the ICA). Finally, a recent study [1] of the spinal cord blood volume in humans using perfusionweighted MRI reported higher values (approximately 4.3 ml/100 g), which may be attributed to the different modalities, as the results between CT and MRI may not be directly interchangeable [23], as well as to the known overestimation of the blood volume by using T1-weighted steady-state methods [24].…”

“…The dynamic contrast-enhanced CT or MRI has been increasingly utilised in the last years for quantifying hemodynamics in the brain and in other organs (such as the head and neck, lung, liver, intestine, kidney, prostate and muscle), but there is scarce evidence for perfusionweighted MR imaging of the spinal cord in humans [1,2], and there are no initial data using perfusion CT imaging. Today, two commercially available software packages are widely used for quantification of perfusion CT studies.…”

Assessment of Craniospinal Pressure-Volume Indices

“…The magnitude of the missing spinal arterial flow is difficult to estimate because there are no reliable reports of this quantity. 32 However, this missing flow is likely a small fraction compared with the blood flow to the brain, and thus the resulting underestimation of PVI CC is also small.…”

Diffusion tensor imaging in the assessment of ossification of the posterior longitudinal ligament: a report on preliminary results in 3 cases and review of the literature

“…Noninvasive MR perfusion and vascular permeability techniques being developed in step with spinal DT imaging protocols may provide more definitive evidence. 18,26 Regardless of the mechanism, reproducible patterns of neural degeneration are found on imaging modalities such as DT studies.…”