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High temporal resolution parametric MRI monitoring of the initial ischemia/reperfusion phase in experimental acute kidney injury.

Pohlmann A, Hentschel J, Fechner M, Hoff U, Bubalo G, Arakelyan K, Cantow K, Seeliger E, Flemming B, Waiczies H, Waiczies S, Schunck WH, Dragun D, Niendorf T - PLoS ONE (2013)

Bottom Line: There is an unmet need to better understand the mechanisms operative during the initial phase of ischemic AKI.Our study demonstrated for the first time that continuous and high temporal resolution parametric MRI is feasible for in-vivo monitoring and characterization of I/R induced AKI in rats.This technique may help in the identification of the timeline of key events responsible for development of renal damage in hypoperfusion-induced AKI.

View Article: PubMed Central - PubMed

Affiliation: Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany. andreas.pohlmann@mdc-berlin.de

ABSTRACT
Ischemia/reperfusion (I/R) injury, a consequence of kidney hypoperfusion or temporary interruption of blood flow is a common cause of acute kidney injury (AKI). There is an unmet need to better understand the mechanisms operative during the initial phase of ischemic AKI. Non-invasive in vivo parametric magnetic resonance imaging (MRI) may elucidate spatio-temporal pathophysiological changes in the kidney by monitoring the MR relaxation parameters T2* and T2, which are known to be sensitive to blood oxygenation. The aim of our study was to establish the technical feasibility of fast continuous T2*/T2 mapping throughout renal I/R. MRI was combined with a remotely controlled I/R model and a segmentation model based semi-automated quantitative analysis. This technique enabled the detailed assessment of in vivo changes in all kidney regions during ischemia and early reperfusion. Significant changes in T2* and T2 were observed shortly after induction of renal ischemia and during the initial reperfusion phase. Our study demonstrated for the first time that continuous and high temporal resolution parametric MRI is feasible for in-vivo monitoring and characterization of I/R induced AKI in rats. This technique may help in the identification of the timeline of key events responsible for development of renal damage in hypoperfusion-induced AKI.

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Change of renal T2* and T2 during hypoxia, hyperoxia, ischemia and reperfusion.Shown are T2* and T2 difference maps of the kidney (color-coded, overlay on anatomical MR image) between the last time point in each experiment phase and baseline. The three interventions (hypoxia, hyperoxia, ischemia) led to a reasonably homogeneous decrease/increase in both parameters. During ischemia the magnitude of the T2*/T2 reduction exceeded that during hypoxia. Parameter changes in the reperfusion phase clearly differentiated cortex and medulla: while medullary T2*/T2 remained reduced throughout reperfusion, in the cortex T2* returned to baseline and T2 rose above baseline.
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pone-0057411-g006: Change of renal T2* and T2 during hypoxia, hyperoxia, ischemia and reperfusion.Shown are T2* and T2 difference maps of the kidney (color-coded, overlay on anatomical MR image) between the last time point in each experiment phase and baseline. The three interventions (hypoxia, hyperoxia, ischemia) led to a reasonably homogeneous decrease/increase in both parameters. During ischemia the magnitude of the T2*/T2 reduction exceeded that during hypoxia. Parameter changes in the reperfusion phase clearly differentiated cortex and medulla: while medullary T2*/T2 remained reduced throughout reperfusion, in the cortex T2* returned to baseline and T2 rose above baseline.

Mentions: Changes in renal T2* and T2 during hypoxia, hyperoxia, ischemia and reperfusion are illustrated in Figure 6 by T2* and T2 difference maps. Hypoxia/hyperoxia led to a rather uniform T2*/T2 reduction/rise across the kidney. The T2*/T2 reduction in ischemic kidneys exceeded that during hypoxia. Changes in the course of reperfusion clearly differentiated cortex and medulla. In accordance with the ROI data medullary T2*/T2 remained reduced throughout reperfusion, cortical T2* returned to baseline and cortical T2 even rose markedly above baseline.


High temporal resolution parametric MRI monitoring of the initial ischemia/reperfusion phase in experimental acute kidney injury.

Pohlmann A, Hentschel J, Fechner M, Hoff U, Bubalo G, Arakelyan K, Cantow K, Seeliger E, Flemming B, Waiczies H, Waiczies S, Schunck WH, Dragun D, Niendorf T - PLoS ONE (2013)

Change of renal T2* and T2 during hypoxia, hyperoxia, ischemia and reperfusion.Shown are T2* and T2 difference maps of the kidney (color-coded, overlay on anatomical MR image) between the last time point in each experiment phase and baseline. The three interventions (hypoxia, hyperoxia, ischemia) led to a reasonably homogeneous decrease/increase in both parameters. During ischemia the magnitude of the T2*/T2 reduction exceeded that during hypoxia. Parameter changes in the reperfusion phase clearly differentiated cortex and medulla: while medullary T2*/T2 remained reduced throughout reperfusion, in the cortex T2* returned to baseline and T2 rose above baseline.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585384&req=5

pone-0057411-g006: Change of renal T2* and T2 during hypoxia, hyperoxia, ischemia and reperfusion.Shown are T2* and T2 difference maps of the kidney (color-coded, overlay on anatomical MR image) between the last time point in each experiment phase and baseline. The three interventions (hypoxia, hyperoxia, ischemia) led to a reasonably homogeneous decrease/increase in both parameters. During ischemia the magnitude of the T2*/T2 reduction exceeded that during hypoxia. Parameter changes in the reperfusion phase clearly differentiated cortex and medulla: while medullary T2*/T2 remained reduced throughout reperfusion, in the cortex T2* returned to baseline and T2 rose above baseline.
Mentions: Changes in renal T2* and T2 during hypoxia, hyperoxia, ischemia and reperfusion are illustrated in Figure 6 by T2* and T2 difference maps. Hypoxia/hyperoxia led to a rather uniform T2*/T2 reduction/rise across the kidney. The T2*/T2 reduction in ischemic kidneys exceeded that during hypoxia. Changes in the course of reperfusion clearly differentiated cortex and medulla. In accordance with the ROI data medullary T2*/T2 remained reduced throughout reperfusion, cortical T2* returned to baseline and cortical T2 even rose markedly above baseline.

Bottom Line: There is an unmet need to better understand the mechanisms operative during the initial phase of ischemic AKI.Our study demonstrated for the first time that continuous and high temporal resolution parametric MRI is feasible for in-vivo monitoring and characterization of I/R induced AKI in rats.This technique may help in the identification of the timeline of key events responsible for development of renal damage in hypoperfusion-induced AKI.

View Article: PubMed Central - PubMed

Affiliation: Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine, Berlin, Germany. andreas.pohlmann@mdc-berlin.de

ABSTRACT
Ischemia/reperfusion (I/R) injury, a consequence of kidney hypoperfusion or temporary interruption of blood flow is a common cause of acute kidney injury (AKI). There is an unmet need to better understand the mechanisms operative during the initial phase of ischemic AKI. Non-invasive in vivo parametric magnetic resonance imaging (MRI) may elucidate spatio-temporal pathophysiological changes in the kidney by monitoring the MR relaxation parameters T2* and T2, which are known to be sensitive to blood oxygenation. The aim of our study was to establish the technical feasibility of fast continuous T2*/T2 mapping throughout renal I/R. MRI was combined with a remotely controlled I/R model and a segmentation model based semi-automated quantitative analysis. This technique enabled the detailed assessment of in vivo changes in all kidney regions during ischemia and early reperfusion. Significant changes in T2* and T2 were observed shortly after induction of renal ischemia and during the initial reperfusion phase. Our study demonstrated for the first time that continuous and high temporal resolution parametric MRI is feasible for in-vivo monitoring and characterization of I/R induced AKI in rats. This technique may help in the identification of the timeline of key events responsible for development of renal damage in hypoperfusion-induced AKI.

Show MeSH
Related in: MedlinePlus