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Magn Reson Med. 2016 Dec;76(6):1677-1683. doi: 10.1002/mrm.26457. Epub 2016 Sep 26.

Quantitative chemical exchange saturation transfer MRI of intervertebral disc in a porcine model.

Zhou Z1,2, Bez M3, Tawackoli W1,4,5, Giaconi J6, Sheyn D4,5, de Mel S4,5, Maya MM6, Pressman BD6, Gazit Z3,4,5, Pelled G3,4,5, Gazit D3,4,5, Li D1,2,6.

Author information

1
Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.
2
Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA.
3
Skeletal Biotech Laboratory, The Hebrew University-Hadassah Faculty of Dental Medicine, Ein Kerem, Jerusalem, Israel.
4
Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.
5
Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.
6
Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, California, USA.

Abstract

PURPOSE:

Previous studies have associated low pH in intervertebral discs (IVDs) with discogenic back pain. The purpose of this study was to determine whether quantitative CEST (qCEST) MRI can be used to detect pH changes in IVDs in vivo.

METHODS:

The exchange rate ksw between glycosaminoglycan (GAG) protons and water protons was determined from qCEST analysis. Its dependence on pH value was investigated in GAG phantoms with varying pH and concentrations. The relationship between ksw and pH was studied further in vivo in a porcine model on a 3T MR scanner and validated using a pH meter. Sodium lactate was injected into the IVDs to induce various pH values within the discs ranging from 5 to 7.

RESULTS:

Phantom and animal results revealed that ksw measured using qCEST MRI is highly correlated with pH level. In the animal studies, the relationship can be described as ksw  =9.2 × 106 × 10-pH + 196.9, R2  = 0.7883.

CONCLUSION:

The exchange rate between GAG and water protons determined from qCEST MRI is closely correlated with pH value. This technique has the potential to noninvasively measure pH in the IVDs of patients with discogenic pain. Magn Reson Med 76:1677-1683, 2016. © 2016 International Society for Magnetic Resonance in Medicine.

KEYWORDS:

CEST; gagCEST; intervertebral disc; low back pain; pH; quantitative CEST

PMID:
27670140
PMCID:
PMC5561741
DOI:
10.1002/mrm.26457
[Indexed for MEDLINE]
Free PMC Article

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