Reperfused Rat Myocardium Subjected to Various Durations of Ischemia: Estimation of the Distribution Volume of Contrast Material with Echo-planar MR Imaging

Arheden, Håkan; Saeed, Maythem; Higgins, Charles B.; Gao, Dong-Wei; Ursell, Philip C.; Bremerich, Jens; Wyttenbach, Rolf; Dae, Michael W.; Wendland, Michael F.

doi:10.1148/radiology.215.2.r00ma38520

Cited by 123 publications

(130 citation statements)

References 38 publications

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“…Table 1 summarizes these previous findings from other groups. Specifically, the estimates of v e from this study are similar to v e results from autoradiographic imaging and histological sectioning techniques (29)(30)(31) and are comparable to v e estimates from the steady-state Ct/Cb method, using regional changes in signal enhancement (7,9,10,32). v e measurements from histological studies range from 19%-30% depending on the method of chemical fixation and histological analysis.…”

Section: Discussionsupporting

confidence: 76%

“…One limitation of the study is that when computing v e and Ct/Cb, the vascular blood volume was assumed to be a constant Vb=0.04, which was the mean model estimate of Vb from all of the dynamic contrast-enhanced perfusion studies. While this value of Vb is comparable to values found by another group using MRI (18,29), it is lower than estimates of Vb found by some histopathological estimates (30,31), and it may be possible that within a region of myocardium the fraction of tissue comprised of blood vasculature may not be spatially uniform.…”

Section: Discussionsupporting

confidence: 62%

“…It is hypothesized that in regions of the heart where an infarct has occurred, the loss of viable cardiac cells results in an increased distribution volume. Furthermore, (29) reports that v e increases with increased time of coronary artery occlusion and that v e is greater in the core of an infarct than in the peripheral infarct regions. This finding suggests that there may be a range of v e values within an infarct that vary according to the severity of cellular damage in the region.…”

Section: Discussionmentioning

confidence: 99%

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Quantitative myocardial distribution volume from dynamic contrast-enhanced MRI

Pack

DiBella

Wilson

et al. 2008

Magnetic Resonance Imaging

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The objective of this study was to investigate if dynamic contrast-enhanced magnetic resonance imaging (MRI) can be used to quantitate the distribution volume (v e ) in regions of normal and infarcted myocardium. v e reflects the volume of the extra-cellular, extra-vascular space within the myocardial tissue. In regions of the heart where an infarct has occurred, the loss of viable cardiac cells results in an elevated v e compared to normal regions. A quantitative estimate of the magnitude and spatial distribution of v e is significant because it may provide information complementary to delayed enhancement MRI alone.Using a hybrid gradient echo-echo planar imaging (GRE-EPI) pulse sequence on a 1.5T MRI scanner, 12 normal subjects and four infarct patients were imaged dynamically, during the injection of a contrast agent, to measure the regional blood and tissue enhancement in the left ventricular (LV) myocardium. Seven of the normal subjects and all of the infarct patients were also imaged at steadystate contrast enhancement to estimate the steady-state ratio of contrast agent in the tissue and blood (Ct/Cb)-a validated measure of v e . Normal and infarct regions of the LV were manually selected and the blood and tissue enhancement curves were fit to a compartment model to estimate v e . Also, the effect of the vascular blood signal on estimates of v e was evaluated using simulations and in the dynamic and steady-state studies.Aggregate estimates of v e were 23.6% ± 6.3% in normal myocardium and 45.7% ± 3.4% in regions of infarct. These results were not significantly different from the reference standards of Ct/Cb (22.9% ± 6.8% and 42.6% ± 6.3%, p=0.073). From the dynamic contrast-enhanced studies, approximately one minute of scan time was necessary to estimate v e in the normal myocardium to within 10% of the steady-state estimate. In regions of infarct, up to three minutes of dynamic data was required to estimate v e to within 10% of the steady-state v e value.By measuring the kinetics of blood and tissue enhancement in the myocardium during an extended dynamic contrast enhanced MRI study, v e may be estimated using compartment modeling.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

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Quantitative myocardial distribution volume from dynamic contrast-enhanced MRI

Pack

DiBella

Wilson

et al. 2008

Magnetic Resonance Imaging

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“…Ischemically injured myocardium after 30 minutes of occlusion is expected to contain viable and nonviable portions. 22 Two groups were studied (nϭ8 rats per group). Group 1 animals received 0.3 mmol/kg Gd-DTPA on day 1 (2-hour reperfusion) and on day 2 (24-hour reperfusion) and were imaged after each injection.…”

Section: Experimental Protocolmentioning

confidence: 99%

Magnetic Resonance Characterization of the Peri-Infarction Zone of Reperfused Myocardial Infarction With Necrosis-Specific and Extracellular Nonspecific Contrast Media

et al. 2001

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Background-Because ischemically injured myocardium is frequently composed of viable and nonviable portions, a method to discriminate the two is useful for clinical management. Methods and Results-Ischemically injured myocardium was characterized with extracellular nonspecific (Gd-DTPA) and necrosis-specific (mesoporphyrin) MR contrast media in rats. Relaxation rates (R1) were measured on day 1 and day 2 by inversion-recovery echoplanar imaging. Spin-echo imaging was used to define contrast-enhanced regions and regional wall thickening. Gadolinium concentration, area at risk, and infarct size were measured at postmortem examination. ⌬R1 ratio (⌬R1 myocardium /⌬R1 blood ) after administration of Gd-DTPA was greater in ischemically injured myocardium (1.20Ϯ0.15) than in normal myocardium (0.47Ϯ0.05, PϽ0.05), which was attributed to differences in gadolinium concentration and water content. The Gd-DTPA-enhanced region on day 2 was larger (32.8Ϯ0.9%) than true infarction as demonstrated by triphenyltetrazolium chloride (TTC) (24.6Ϯ1.4%, PϽ0.001, rϭ0.21). Bland-Altman analysis revealed that the Gd-DTPA-enhanced region overestimated true infarct size by 7.8Ϯ5.9%. On the other hand, the mesoporphyrin-enhanced region (26.9Ϯ1.8%, PϭNS, rϭ0.87) and true infarct size were identical. The difference in the areas demarcated by the 2 agents is the peri-infarction. Systolic and diastolic MR images revealed no wall thickening in the mesoporphyrin-enhanced region (0.3Ϯ3.3%) but reduced thickening in the Gd-DTPA-enhanced rim (8.5Ϯ5.5%, PϽ0.05). Conclusions-The Gd-DTPA-enhanced region encompasses both viable and nonviable portions of the ischemically injured myocardium. The Gd-DTPA-enhanced area overestimated infarct size, but the mesoporphyrin-enhanced area matched true infarct size. The salvageable peri-infarction zone can be characterized with double-contrast-enhanced and functional MR imaging; the mismatched area of enhancement between the 2 agents shows residual wall thickening.

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“…Its slow clearance, however, is favorable for measurement of extracellular space and assessment of myocardial viability. Arheden et al (21,22) and Pereira et al (23,24) demonstrated that the increase of the fraction of nonviable myocytes is paralleled by an expansion of the extracellular distribution volume from 18% in normal myocardium and Ͼ 80% in infarcted myocardium (21). Measuring the extracellular space with a rapidly clearing standard extracellular contrast agent, however, is difficult (25,26).…”

Section: Extracellular Contrast Mediamentioning

confidence: 99%

Slow clearance gadolinium‐based extracellular and intravascular contrast media for three‐dimensional MR angiography

Bremerich¹,

Colet²,

Giovenzana³

et al. 2001

Magnetic Resonance Imaging

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Reperfused Rat Myocardium Subjected to Various Durations of Ischemia: Estimation of the Distribution Volume of Contrast Material with Echo-planar MR Imaging

Abstract: The fDV of MR contrast material in the periinfarcted rim was significantly (P <. 05) greater than that in the normal myocardium, but significantly less than that in the core of infarcted myocardium.

Cited by 123 publications

References 38 publications

Quantitative myocardial distribution volume from dynamic contrast-enhanced MRI

Quantitative myocardial distribution volume from dynamic contrast-enhanced MRI

Magnetic Resonance Characterization of the Peri-Infarction Zone of Reperfused Myocardial Infarction With Necrosis-Specific and Extracellular Nonspecific Contrast Media

Slow clearance gadolinium‐based extracellular and intravascular contrast media for three‐dimensional MR angiography

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