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Delayed urea differential enhancement CEST (dudeCEST)-MRI with T1 correction for monitoring renal urea handling.
Shin, Soo Hyun; Wendland, Michael F; Vandsburger, Moriel H.
Afiliación
  • Shin SH; Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA.
  • Wendland MF; Berkeley Preclinical Imaging Core (BPIC), University of California, Berkeley, Berkeley, California, USA.
  • Vandsburger MH; Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA.
Magn Reson Med ; 85(5): 2791-2804, 2021 05.
Article en En | MEDLINE | ID: mdl-33180343
ABSTRACT

PURPOSE:

We demonstrate a method of delayed urea differential enhancement CEST for probing urea recycling action of the kidney using expanded multi-pool Lorentzian fitting and apparent exchange-dependent relaxation compensation.

METHODS:

T1 correction of urea CEST contrast by apparent exchange-dependent relaxation was tested in phantoms. Nine mice were scanned at 7 Tesla following intraperitoneal injection of 2M 150 µL urea, and later saline. T1 maps and Z-spectra were acquired before and 20 and 40 min postinjection. Z-spectra were fit to a 7-pool Lorentzian model for CEST quantification and compared to urea assay of kidney homogenate. Renal injury was induced by aristolochic acid in 7 mice, and the same scan protocol was performed.

RESULTS:

Apparent exchange-dependent relaxation corrected for variable T1 times in phantoms. Urea CEST contrast at +1 ppm increased significantly at both time points following urea injection in the inner medulla and papilla. When normalizing the postinjection urea CEST contrast to the corresponding baseline value, both urea and saline injection resulted in identical fold changes in urea CEST contrast. Urea assay of kidney homogenate showed a significant correlation to both apparent exchange-dependent relaxation (R2 = 0.4687, P = .0017) and non-T1 -corrected Lorentzian amplitudes (R2 = 0.4964, P = .0011). Renal injury resulted in increased T1 time in the cortex and reduced CEST contrast change upon urea and saline infusion.

CONCLUSION:

Delayed urea enhancement following infusion can provide insight into renal urea handling. In addition, changes in CEST contrast at 1.0 ppm following saline infusion may provide insight into renal function.
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Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Urea / Imagen por Resonancia Magnética Tipo de estudio: Prognostic_studies Límite: Animals Idioma: En Revista: Magn Reson Med Asunto de la revista: DIAGNOSTICO POR IMAGEM Año: 2021 Tipo del documento: Article País de afiliación: Estados Unidos

Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Urea / Imagen por Resonancia Magnética Tipo de estudio: Prognostic_studies Límite: Animals Idioma: En Revista: Magn Reson Med Asunto de la revista: DIAGNOSTICO POR IMAGEM Año: 2021 Tipo del documento: Article País de afiliación: Estados Unidos