Early effects of an x‐ray contrast medium on renal T<sub>2</sub>*/T<sub>2</sub><scp>MRI</scp> as compared to short‐term hyperoxia, hypoxia and aortic occlusion in rats

Arakelyan, Karen; Cantow, Kathleen; Hentschel, Jan; Flemming, Bert; Pohlmann, Andreas; Ladwig, Mechthild; Niendorf, Thoralf; Seeliger, Erdmann

doi:10.1111/apha.12094

Cited by 30 publications

(34 citation statements)

References 49 publications

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“…13 In animal models, several investigators have utilized BOLD MRI to demonstrate that breathing pure oxygen increases oxygenation in all renal compartments. 4,12 Pohlmann et al 4 confirmed these findings in pigs with simultaneous BOLD MRI measurements and direct measurements of pO 2 performed in the same kidney. Although the data are not entirely consistent, most BOLD MRI studies in humans have demonstrated that breathing 100% oxygen increases intrarenal oxygenation in the medulla but not in the cortex, suggesting nonsaturation of renal medullary oxygenation under physiologic conditions.…”

mentioning

confidence: 77%

“…3 Consistent with these observations, inhalation of pure nitrogen or 10% oxygen reduced oxygenation in all renal compartments in experimental animals. 4,11,12 Breathing 100% oxygen increases arterial plasma pO 2 , but has a minimal effect on the deoxyhemoglobin/ oxyhemoglobin ratio in healthy subjects since hemoglobin oxygen saturation is nearly complete. However, inhalation of …”

Section: Inspiratory Oxygen Levelmentioning

confidence: 99%

“…12,22,42,[55][56][57][58][59] In rats treated with cyclooxygenase and nitric oxide synthase inhibitors, administration of a first-generation ionic hyperosmolar contrast agent reduced medullary oxygenation. 55 Administration of a third-generation nonionic, iso-osmolar, high viscosity contrast agent caused an even greater reduction in medullary oxygenation.…”

Section: Contrast-associated Nephropathymentioning

confidence: 99%

“…58 In rats and swine studied by BOLD MRI, administration of radiocontrast caused an early and transient increase in medullary T2* followed by a sustained reduction below baseline, with minimal changes observed in the renal cortex. 12,22,42,57 Arakelyan et al 12 attributed the initial rise in T2* to an increase in renal tubular volume due to dye-induced osmotic diuresis resulting in a decreased blood volume fraction. These authors relied on studies by earlier investigators to conclude that medullary blood flow does not change after administration of radiocontrast.…”

Section: Contrast-associated Nephropathymentioning

confidence: 99%

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Blood oxygenation level-dependent MRI for assessment of renal oxygenation

Neugarten¹,

Golestaneh²

2014

IJNRD

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Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) has recently emerged as an important noninvasive technique to assess intrarenal oxygenation under physiologic and pathophysiologic conditions. Although this tool represents a major addition to our armamentarium of methodologies to investigate the role of hypoxia in the pathogenesis of acute kidney injury and progressive chronic kidney disease, numerous technical limitations confound interpretation of data derived from this approach. BOLD MRI has been utilized to assess intrarenal oxygenation in numerous experimental models of kidney disease and in human subjects with diabetic and nondiabetic chronic kidney disease, acute kidney injury, renal allograft rejection, contrast-associated nephropathy, and obstructive uropathy. However, confidence in conclusions based on data derived from BOLD MRI measurements will require continuing advances and technical refinements in the use of this technique.

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mentioning

confidence: 77%

Section: Inspiratory Oxygen Levelmentioning

confidence: 99%

Section: Contrast-associated Nephropathymentioning

confidence: 99%

Section: Contrast-associated Nephropathymentioning

confidence: 99%

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Blood oxygenation level-dependent MRI for assessment of renal oxygenation

Neugarten¹,

Golestaneh²

2014

IJNRD

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“…R2* (=1/T2*) relaxation rate has been used as BOLD MRI parameter based on our previous reports 8, 9 . Others have also concluded that R2* changes post-iodinated contrast are reflective of renal oxygenation 16 . The renal injury after iodinated contrast was confirmed using uNGAL.…”

Section: Introductionmentioning

confidence: 99%

Effect of Iodinated Contrast Medium in Diabetic Rat Kidneys as Evaluated by Blood-Oxygenation-Level–Dependent Magnetic Resonance Imaging and Urinary Neutrophil Gelatinase-Associated Lipocalin

Lü

Franklin

et al. 2015

Investigative Radiology

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Objectives To assess if streptozotocin (STZ) induced diabetic rats develop iodinated contrast induced acute kidney injury (CIAKI). The intra-renal R2* (= 1/ T2*) was evaluated continuously before-during-after contrast administration. Renal injury was confirmed by urinary neutrophil gelatinase-associated lipocalin (uNGAL) measurements. Materials and Methods Six Sprague-Dawley rats were administered STZ to induce diabetes (Group 1). R2* was measured before, during, and after administration of iodixanol. R2* readings were sampled from four renal regions: inner medulla, inner stripe of outer medulla (ISOM), outer stripe of outer medulla, and cortex. Peak R2* and initial up-slope of R2* increase following iodinated contrast were calculated. Data from 12 non-diabetic rats pre-treated with nitric oxide synthase and prostaglandin inhibitors to induce susceptibility to CIAKI (pre-treatment model) from a previous study were re-analyzed for peak R2* and initial up-slope of R2* increase following contrast. Six of these animals received saline (Group 2) and the other six received furosemide (Group 3) prior to idoxianol. Results Peak R2* and initial up-slope of R2* increase were used as BOLD response parameters. R2* in ISOM were comparable in all three groups prior to administration of furosemide. Except for the furosemide group, ISOM showed a rapid increase in R2* immediately following contrast administration. Unlike the L-NAME & indomethacin treated groups, the diabetic group showed a quick reversal of R2* towards baseline measurements after contrast administration. Urinary NGAL indicated significant increase in diabetic rats 4 hours following contrast administration. The observed trends with peak R2* and initial up-slope of R2* increase in renal ISOM were in agreement with those of uNGAL. Conclusion The STZ induced diabetic rat may be suitable for studying the effects of iodinated contrast on renal oxygenation status and may mimic human condition closer than the pre-treatment model described before. The peak R2* value and initial up-slope of R2* in ISOM appear to be effective MRI markers to predict renal injury following administration of an iodinated contrast agent.

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Physiological system analysis of the kidney by high‐temporal‐resolution monitoring of an oxygenation step response

Zhao

Pohlmann

Feng

et al. 2020

Magnetic Resonance in Med

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Purpose: Examine the feasibility of characterizing the regulation of renal oxygenation using high-temporal-resolution monitoring of the T * 2 response to a step-like oxygenation stimulus. Methods: For T * 2 mapping, multi-echo gradient-echo imaging was used (temporal resolution = 9 seconds). A step-like renal oxygenation challenge was applied involving sequential exposure to hyperoxia (100% O 2), hypoxia (10% O 2 + 90% N 2), and hyperoxia (100% O 2). In vivo experiments were performed in healthy rats (N = 10) and in rats with bilateral ischemia-reperfusion injury (N = 4). To assess the step response of renal oxygenation, a second-order exponential model was used (model parameters: amplitude [A], time delay [Δt], damping constant [D], and period of the oscillation [T]) for renal cortex, outer stripe of the outer medulla, inner stripe of the outer medulla, and inner medulla. Results: The second-order exponential model permitted us to model the exponential T * 2 recovery and the superimposed T * 2 oscillation following renal oxygenation stimulus. The in vivo experiments revealed a difference in D outer medulla between healthy controls (D < 1, indicating oscillatory recovery) and ischemia-reperfusion injury (D > 1, reflecting aperiodic recovery). The increase in D outer medulla by a factor of 3.7 (outer stripe of the outer medulla) and 10.0 (inner stripe of the outer medulla) suggests that this parameter might be rather sensitive to (patho)physiological oxygenation changes. Conclusion: This study demonstrates the feasibility of monitoring the dynamic oxygenation response of renal tissues to a step-like oxygenation challenge using | 335 ZHAO et Al.

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Early effects of an x‐ray contrast medium on renal T₂*/T₂MRI as compared to short‐term hyperoxia, hypoxia and aortic occlusion in rats

Cited by 30 publications

References 49 publications

Blood oxygenation level-dependent MRI for assessment of renal oxygenation

Blood oxygenation level-dependent MRI for assessment of renal oxygenation

Effect of Iodinated Contrast Medium in Diabetic Rat Kidneys as Evaluated by Blood-Oxygenation-Level–Dependent Magnetic Resonance Imaging and Urinary Neutrophil Gelatinase-Associated Lipocalin

Physiological system analysis of the kidney by high‐temporal‐resolution monitoring of an oxygenation step response

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Early effects of an x‐ray contrast medium on renal T2*/T2MRI as compared to short‐term hyperoxia, hypoxia and aortic occlusion in rats

Cited by 30 publications

References 49 publications

Blood oxygenation level-dependent MRI for assessment of renal oxygenation

Blood oxygenation level-dependent MRI for assessment of renal oxygenation

Effect of Iodinated Contrast Medium in Diabetic Rat Kidneys as Evaluated by Blood-Oxygenation-Level–Dependent Magnetic Resonance Imaging and Urinary Neutrophil Gelatinase-Associated Lipocalin

Physiological system analysis of the kidney by high‐temporal‐resolution monitoring of an oxygenation step response

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Early effects of an x‐ray contrast medium on renal T₂*/T₂MRI as compared to short‐term hyperoxia, hypoxia and aortic occlusion in rats