Document Detail

Renal blood oxygenation level-dependent imaging: contribution of R2 to R2* values.
MedLine Citation:
PMID:  23385400     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: The aim of this study was to assess the impact of oral water and intravenous furosemide challenges on blood oxygenation level-dependent magnetic resonance imaging measurements in the kidney and to examine the contribution of R2 (=1/T2) to changes in R2* (=1/T2*).
MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act-compliant study had institutional review board approval, and written informed consent was obtained from all subjects. Nine healthy volunteers were imaged at 3 T on 2 visits. During each visit, a baseline fasting magnetic resonance acquisition was followed by a diuretic challenge: oral water load for the first visit and furosemide for the second. R2* and R2 values in the renal cortex and medulla were measured using multiple gradient echo and multiple spin echo sequences, respectively, and R2' values were computed as R2' = R2* - R2. Timed urinary output was also measured.
RESULTS: Averaged across all subjects, the R2* response to furosemide was greater than to water and greater in the medulla than the cortex. The mean R2 responses exhibited the same trends but were uniformly smaller than the mean R2* responses. The peak changes in R2* and R2 appeared, on average, 10 to 14 minutes before peak urinary output. The median percentage contribution of R2 to R2* changes was 16% in the medulla after both challenges. In the cortex, the median contribution was 48% after water load and 58% after furosemide challenge.
CONCLUSIONS: The contributions of R2 to R2* changes after water load and furosemide challenge are not negligible, especially in the renal cortex. In routine clinical practice, R2* could be used alone as a rough surrogate for R2' in the medulla. However, in the cortex, both R2 and R2* should be measured to obtain accurate values of R2'.
Pierre-Hugues Vivier; Pippa Storey; Hersh Chandarana; Akira Yamamoto; Kristopher Tantillo; Umer Khan; Jeff L Zhang; Eric E Sigmund; Henry Rusinek; James S Babb; Michael Bubenheim; Vivian S Lee
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Investigative radiology     Volume:  48     ISSN:  1536-0210     ISO Abbreviation:  Invest Radiol     Publication Date:  2013 Jul 
Date Detail:
Created Date:  2013-06-03     Completed Date:  2014-01-06     Revised Date:  2014-01-14    
Medline Journal Info:
Nlm Unique ID:  0045377     Medline TA:  Invest Radiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  501-8     Citation Subset:  IM    
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MeSH Terms
Administration, Oral
Diuretics / administration & dosage
Furosemide / administration & dosage*
Injections, Intravenous
Kidney / drug effects,  metabolism*
Kidney Function Tests / methods
Magnetic Resonance Angiography / methods*
Oximetry / methods*
Oxygen / blood*
Renal Circulation / drug effects,  physiology*
Tissue Distribution
Water / administration & dosage*
Young Adult
Grant Support
Reg. No./Substance:
0/Diuretics; 059QF0KO0R/Water; 7LXU5N7ZO5/Furosemide; S88TT14065/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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