Abstract
Determination of the chemical shift and integral of the myocardial intracellular inorganic phosphate (P(i)) resonance by 31P magnetic resonance spectroscopy (MRS) is often precluded due to a large overlapping signal from 2,3-diphosphoglycerate (2,3-DPG) from chamber and myocardial blood. This report demonstrates the use of radiofrequency (RF) magnetic field gradient echoes (RFGE) to eliminate signals from 2,3-DPG in flowing blood, while retaining signals from intracellular myocardial P(i), ATP, and phosphocreatine (PCr). The ECG-triggered 31P spectra were acquired from the myocardium of open chest pigs using a Philips Gyroscan 2-T magnetic resonance spectrometer. A 2.5-cm-diameter surface coil attached to the myocardium was used to provide the RF gradient as well as for excitation and detection of signals. Optimal performance of the RFGE pulse sequence was obtained when the RF gradient pulses were centered at peak diastole or peak systole. Under these conditions, 2,3-DPG signals were completely suppressed, and sensitivity was usually sufficient to allow detection of a well-resolved P(i) signal. Myocardial pH determined from RFGE experiments was 7.16 ± 0.10, and the ratio of the integrals of the P(i) and ATP resonances (P(i)/ATP) was 0.24. The mean signal-to-noise ratio (S/N) for PCr in control spectra acquired in 4 min was 19/1, while the mean S/N for PCr in RFGE-edited spectra acquired in 15 min was 11/1, demonstrating that the present implementation of the RFGE method results in significant loss in sensitivity. These experiments demonstrate that RFGE-editing allows accurate determination of the chemical shift and integral of the P(i) resonance in blood-perfused myocardium in situ.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 171-183 |
| Number of pages | 13 |
| Journal | Magnetic Resonance in Medicine |
| Volume | 20 |
| Issue number | 2 |
| State | Published - 1991 |
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ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology
Cite this
31P MRS of myocardial inorganic phosphate using radiofrequency gradient echoes. / Gober, J. R.; Schwartz, G. G.; Schaefer, Saul; Massie, B. M.; Matson, G. B.; Weiner, M. W.; Karczmar, G. S.
In: Magnetic Resonance in Medicine, Vol. 20, No. 2, 1991, p. 171-183.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - 31P MRS of myocardial inorganic phosphate using radiofrequency gradient echoes
AU - Gober, J. R.
AU - Schwartz, G. G.
AU - Schaefer, Saul
AU - Massie, B. M.
AU - Matson, G. B.
AU - Weiner, M. W.
AU - Karczmar, G. S.
PY - 1991
Y1 - 1991
N2 - Determination of the chemical shift and integral of the myocardial intracellular inorganic phosphate (P(i)) resonance by 31P magnetic resonance spectroscopy (MRS) is often precluded due to a large overlapping signal from 2,3-diphosphoglycerate (2,3-DPG) from chamber and myocardial blood. This report demonstrates the use of radiofrequency (RF) magnetic field gradient echoes (RFGE) to eliminate signals from 2,3-DPG in flowing blood, while retaining signals from intracellular myocardial P(i), ATP, and phosphocreatine (PCr). The ECG-triggered 31P spectra were acquired from the myocardium of open chest pigs using a Philips Gyroscan 2-T magnetic resonance spectrometer. A 2.5-cm-diameter surface coil attached to the myocardium was used to provide the RF gradient as well as for excitation and detection of signals. Optimal performance of the RFGE pulse sequence was obtained when the RF gradient pulses were centered at peak diastole or peak systole. Under these conditions, 2,3-DPG signals were completely suppressed, and sensitivity was usually sufficient to allow detection of a well-resolved P(i) signal. Myocardial pH determined from RFGE experiments was 7.16 ± 0.10, and the ratio of the integrals of the P(i) and ATP resonances (P(i)/ATP) was 0.24. The mean signal-to-noise ratio (S/N) for PCr in control spectra acquired in 4 min was 19/1, while the mean S/N for PCr in RFGE-edited spectra acquired in 15 min was 11/1, demonstrating that the present implementation of the RFGE method results in significant loss in sensitivity. These experiments demonstrate that RFGE-editing allows accurate determination of the chemical shift and integral of the P(i) resonance in blood-perfused myocardium in situ.
AB - Determination of the chemical shift and integral of the myocardial intracellular inorganic phosphate (P(i)) resonance by 31P magnetic resonance spectroscopy (MRS) is often precluded due to a large overlapping signal from 2,3-diphosphoglycerate (2,3-DPG) from chamber and myocardial blood. This report demonstrates the use of radiofrequency (RF) magnetic field gradient echoes (RFGE) to eliminate signals from 2,3-DPG in flowing blood, while retaining signals from intracellular myocardial P(i), ATP, and phosphocreatine (PCr). The ECG-triggered 31P spectra were acquired from the myocardium of open chest pigs using a Philips Gyroscan 2-T magnetic resonance spectrometer. A 2.5-cm-diameter surface coil attached to the myocardium was used to provide the RF gradient as well as for excitation and detection of signals. Optimal performance of the RFGE pulse sequence was obtained when the RF gradient pulses were centered at peak diastole or peak systole. Under these conditions, 2,3-DPG signals were completely suppressed, and sensitivity was usually sufficient to allow detection of a well-resolved P(i) signal. Myocardial pH determined from RFGE experiments was 7.16 ± 0.10, and the ratio of the integrals of the P(i) and ATP resonances (P(i)/ATP) was 0.24. The mean signal-to-noise ratio (S/N) for PCr in control spectra acquired in 4 min was 19/1, while the mean S/N for PCr in RFGE-edited spectra acquired in 15 min was 11/1, demonstrating that the present implementation of the RFGE method results in significant loss in sensitivity. These experiments demonstrate that RFGE-editing allows accurate determination of the chemical shift and integral of the P(i) resonance in blood-perfused myocardium in situ.
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M3 - Article
C2 - 1775045
AN - SCOPUS:0025917911
VL - 20
SP - 171
EP - 183
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
SN - 0740-3194
IS - 2
ER -