Quantification of human high-energy phosphate metabolite concentrations at 3T with partial volume and sensitivity corrections

Abdel Monem M El-Sharkawy, Refaat E. Gabr, Michael Schar, Robert George Weiss, Paul A Bottomley

Research output: Contribution to journalArticle

Abstract

Practical noninvasive methods for the measurement of absolute metabolite concentrations are key to the assessment of the depletion of myocardial metabolite pools which occurs with several cardiac diseases, including infarction and heart failure. Localized MRS offers unique noninvasive access to many metabolites, but is often confounded by nonuniform sensitivity and partial volume effects in the large, poorly defined voxels commonly used for the detection of low-concentration metabolites with surface coils. These problems are exacerbated at higher magnetic field strengths by greater radiofrequency (RF) field inhomogeneity and differences in RF penetration with heteronuclear concentration referencing. An example is the 31P measurement of cardiac adenosine triphosphate (ATP) and phosphocreatine (PCr) concentrations, which, although central to cardiac energetics, have not been measured at field strengths above 1.5T. Here, practical acquisition and analysis protocols are presented for the quantification of [PCr] and [ATP] with one-dimensionally resolved surface coil spectra and concentration referencing at 3T. The effects of nonuniform sensitivity and partial tissue volumes are addressed at 3T by the application of MRI-based three-dimensional sensitivity weighting and tissue segmentation. The method is validated in phantoms of different sizes and concentrations, and used to measure [PCr] and [ATP] in healthy subjects. In calf muscle (n=8), [PCr]=24.7±3.4 and [ATP]=5.7±1.3μmol/g wet weight, whereas, in heart (n=18), [PCr]=10.4±1.5 and [ATP]=6.0±1.1μmol/g wet weight (all mean±SD), consistent with previous reports at lower fields. The method enables, for the first time, the efficient, semi-automated quantification of high-energy phosphate metabolites in humans at 3T with nonuniform excitation and detection.

Original languageEnglish (US)
Pages (from-to)1363-1371
Number of pages9
JournalNMR in Biomedicine
Volume26
Issue number11
DOIs
StatePublished - Nov 2013

Fingerprint

Phosphocreatine
Metabolites
Adenosine Triphosphate
Phosphates
Tissue
Weights and Measures
Magnetic Fields
Magnetic resonance imaging
Infarction
Muscle
Heart Diseases
Healthy Volunteers
Heart Failure
Magnetic fields
Muscles

Keywords

  • 3T
  • High field
  • Human heart
  • Metabolism
  • Phosphorus
  • Quantification

ASJC Scopus subject areas

  • Spectroscopy
  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging

Cite this

Quantification of human high-energy phosphate metabolite concentrations at 3T with partial volume and sensitivity corrections. / El-Sharkawy, Abdel Monem M; Gabr, Refaat E.; Schar, Michael; Weiss, Robert George; Bottomley, Paul A.

In: NMR in Biomedicine, Vol. 26, No. 11, 11.2013, p. 1363-1371.

Research output: Contribution to journalArticle

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