Measurement of creatine kinase reaction rate in human brain using magnetization transfer image-selected in vivo spectroscopy (MT-ISIS) and a volume ³¹P/¹H radiofrequency coil in a clinical 3-T MRI system.

NMR in biomedicine · 2011 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 3262

Study snapshot

PublicationNMR in biomedicine · 2011

Study typeexposure_assessment

Reported directionUnclear

Evidence ratingInsufficient

Abstract

High-energy phosphate metabolism, which allows the synthesis and regeneration of adenosine triphosphate (ATP), is a vital process for neuronal survival and activity. In particular, creatine kinase (CK) serves as an energy reservoir for the rapid buffering of ATP levels. Altered CK enzyme activity, reflecting compromised high-energy phosphate metabolism or mitochondrial dysfunction in the brain, can be assessed using magnetization transfer (MT) MRS. MT (31)P MRS has been used to measure the forward CK reaction rate in animal and human brain, employing a surface radiofrequency coil. However, long acquisition times and excessive radiofrequency irradiation prevent these methods from being used routinely for clinical evaluations. In this article, a new MT (31)P MRS method is presented, which can be practically used to measure the CK forward reaction rate constant in a clinical MRI system employing a volume head (31)P coil for spatial localization, without contamination from the scalp muscle, and an acquisition time of 30 min. Other advantages associated with the method include radiofrequency homogeneity within the regions of interest of the brain using a volume coil with image-selected in vivo spectroscopy localization, and reduction of the specific absorption rate using nonadiabatic radiofrequency pulses for MT saturation. The mean value of k(f) was measured as 0.320 ± 0.075 s(-1) from 10 healthy volunteers with an age range of 18-40 years. These values are consistent with those obtained using earlier methods, and the technique may be used routinely to evaluate energetic processes in the brain on a clinical MRI system.

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Study typeexposure_assessment

Effect directionunclear

Population10 healthy volunteers (age 18–40 years)

Sample size10

Exposure30 min acquisition time

Evidence strengthInsufficientConfidence: 66% · Peer reviewed: yes

Main findings

A new MT 31P MRS method using a volume head 31P coil with ISIS localization was presented for measuring the CK forward reaction rate in a clinical 3-T MRI system with a 30 min acquisition time. The mean k_f measured in 10 healthy volunteers was 0.320 ± 0.075 s^-1, consistent with earlier methods; the method also aimed to reduce specific absorption rate using nonadiabatic RF pulses.

Outcomes measured

Creatine kinase (CK) forward reaction rate constant (k_f) in human brain measured by MT 31P MRS

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": null,
    "source": "clinical 3-T MRI system (volume 31P/1H radiofrequency coil)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "30 min acquisition time"
  },
  "population": "10 healthy volunteers (age 18–40 years)",
  "sample_size": 10,
  "outcomes": [
    "Creatine kinase (CK) forward reaction rate constant (k_f) in human brain measured by MT 31P MRS"
  ],
  "main_findings": "A new MT 31P MRS method using a volume head 31P coil with ISIS localization was presented for measuring the CK forward reaction rate in a clinical 3-T MRI system with a 30 min acquisition time. The mean k_f measured in 10 healthy volunteers was 0.320 ± 0.075 s^-1, consistent with earlier methods; the method also aimed to reduce specific absorption rate using nonadiabatic RF pulses.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.66,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "3-T MRI",
    "magnetization transfer",
    "31P MRS",
    "creatine kinase",
    "radiofrequency coil",
    "specific absorption rate",
    "ISIS localization",
    "brain energetics"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.2,
      "reason": "Mentions specific absorption rate (SAR) reduction in an MRI RF method; no explicit policy focus."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1002/nbm.1636
PubMed: 21834000

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