Increased blood oxygen level-dependent (BOLD) sensitivity in the mouse somatosensory cortex during electrical forepaw stimulation using a cryogenic radiofrequency probe.

NMR in biomedicine · 2011 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 3274

Study snapshot

PublicationNMR in biomedicine · 2011

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

Functional MRI (fMRI) based on the blood oxygen level-dependent (BOLD) contrast is widely used in preclinical neuroscience. The small dimensions of rodent brain place high demands on spatial resolution, and hence on the sensitivity of the fMRI experiment. This work investigates the performance of a 400-MHz cryogenic quadrature transceive radiofrequency probe (CryoProbe) with respect to the enhancement of the BOLD sensitivity. For this purpose, BOLD fMRI experiments were performed in mice during electrical forepaw stimulation using the CryoProbe and a conventional room temperature surface coil of comparable dimensions. Image signal-to-noise ratio (SNR) and temporal SNR were evaluated as quality measures for individual images and for fMRI time series of images, resulting in gains (mean ± standard deviation) with factors of 3.1 ± 0.7 and 1.8 ± 1.0 when comparing the CryoProbe and room temperature coil. The CryoProbe thermal shield temperature did not affect the noise characteristics, with temporal noise levels being 63 ± 16% of the corresponding room temperature value. However, a significant effect on BOLD amplitudes was found, which was attributed to temperature-dependent baseline cerebral blood volumes. Defined local thermal conditions were found to be a critical parameter for achieving an optimal and reproducible fMRI signal. In summary, the CryoProbe represents an attractive alternative for the enhancement of image SNR, temporal SNR and BOLD sensitivity in mouse fMRI experiments.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionunclear

PopulationMice

Sample sizeNot supplied

Exposure400 MHz

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

This study compared a 400-MHz cryogenic quadrature transceive RF probe (CryoProbe) versus a conventional room-temperature surface coil during mouse BOLD fMRI with electrical forepaw stimulation. Image SNR and temporal SNR were higher with the CryoProbe (gains of 3.1 ± 0.7 and 1.8 ± 1.0, respectively), and temporal noise levels were 63 ± 16% of the room-temperature value. A significant effect on BOLD amplitudes was observed and attributed to temperature-dependent baseline cerebral blood volumes; defined local thermal conditions were important for reproducible fMRI signal.

Outcomes measured

BOLD sensitivity
BOLD amplitudes
image signal-to-noise ratio (SNR)
temporal SNR
temporal noise levels
baseline cerebral blood volumes (temperature-dependent)

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "MRI radiofrequency probe (CryoProbe)",
    "frequency_mhz": 400,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Mice",
  "sample_size": null,
  "outcomes": [
    "BOLD sensitivity",
    "BOLD amplitudes",
    "image signal-to-noise ratio (SNR)",
    "temporal SNR",
    "temporal noise levels",
    "baseline cerebral blood volumes (temperature-dependent)"
  ],
  "main_findings": "This study compared a 400-MHz cryogenic quadrature transceive RF probe (CryoProbe) versus a conventional room-temperature surface coil during mouse BOLD fMRI with electrical forepaw stimulation. Image SNR and temporal SNR were higher with the CryoProbe (gains of 3.1 ± 0.7 and 1.8 ± 1.0, respectively), and temporal noise levels were 63 ± 16% of the room-temperature value. A significant effect on BOLD amplitudes was observed and attributed to temperature-dependent baseline cerebral blood volumes; defined local thermal conditions were important for reproducible fMRI signal.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "fMRI",
    "BOLD",
    "mouse",
    "somatosensory cortex",
    "electrical forepaw stimulation",
    "cryogenic RF probe",
    "CryoProbe",
    "400 MHz",
    "signal-to-noise ratio",
    "temperature",
    "cerebral blood volume"
  ],
  "suggested_hubs": [
    {
      "slug": "engineering",
      "weight": 0.9,
      "reason": "Method/technology study evaluating an MRI RF probe (CryoProbe) performance and thermal effects on BOLD fMRI signal quality."
    }
  ]
}

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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.1613
PubMed: 22945293

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