2133 Effect of the bolus size on the quantification of myocardial perfusion using MRI

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Meeting abstract

2133 Effect of the bolus size on the quantification of myocardial perfusion using MRI Marko Ivancevic*, Jean-Luc Daire, Michel Kocher, Alberto Righetti, Dominique Didier and Jean-Paul Vallée Address: Geneva University Hospital, Geneva, Switzerland * Corresponding author

from 11th Annual SCMR Scientific Sessions Los Angeles, CA, USA. 1–3 February 2008 Published: 22 October 2008 Journal of Cardiovascular Magnetic Resonance 2008, 10(Suppl 1):A402

doi:10.1186/1532-429X-10-S1-A402

Abstracts of the 11th Annual SCMR Scientific Sessions - 2008

Meeting abstracts – A single PDF containing all abstracts in this Supplement is available here. http://www.biomedcentral.com/content/pdf/1532-429X-10-S1-info.pdf

This abstract is available from: http://jcmr-online.com/content/10/S1/A402 © 2008 Ivancevic et al; licensee BioMed Central Ltd.

Introduction A limitation of MRI for cardiac perfusion on routine clinical MR scanners is the trade-off between the temporal resolution and spatial coverage. Assuming that a higher contrast media dose and a slower injection rate allow lower sampling rate without a significant loss of precision in an one compartmental model, we performed a simulation study to compare two contrast injection strategies (wide and narrow bolus). The validity of the protocol was then demonstrated in patients with a history of myocardial infarction, using 201-Tl SPECT imaging as reference.

Methods The myocardial perfusion is quantified using the one compartment model described by: dCmyo(t)/dt = K1Cart(t) – K2Cmyo(t) where Cart(t) and Cmyo(t) are the arterial and myocardial signal intensity time curves respectively, K1 the perfusion index related to the first order transfer constant from the LV blood to the myocardium and the ratio K1/K2 the fractional distribution volume of the contrast media.

The output error (OE) method was used as a system identification method to estimate K1 and K2. Finally, estimated values of K1 and K2 are described for different noise indices (the standard deviation of a zero mean Gaussian process varies from 0 to 10%) and different under-sampling strategies. Bias and standard deviation of fitted K1 and K2 values were described in each case as well as the Bode diagram. (Figure 1 and 2). Clinical study The validity of the protocol was then demonstrated in 12 patients with a history of myocardial infarction, using 201-Tl SPECT imaging as reference. The MR perfusion sequence was a T1 weighted FGRE sequence with eight slices (4 short-axis, and 4 long-axis) acquired during three to six cardiac cycles, depending on patient's heart rate. the average inter-image delay was 4 seconds (± 0.5). A bolus of 0.08 mmol/kg Gd-DTPA was injected in a brachial vein at 0.5 ml/s injection rate. Standard one compartment model analysis was then applied.

Results Simulation study to evaluate the effect of the bolus shape on the model, two arterial input functions (AIF), narrow (0.035 mmol/kg at 5 cc/sec) and wide (0.08 mmol/kg at 0.5 cc/sec) were derived from re