In Vivo 1H MR Spectroscopy of Human Head and Neck Lymph Node Metastasis and Comparison with Oxygen Tension Measurements
Josh M. Star-Lacka,
Eifar Adalsteinssona,
Markus F. Adama,
David J. Terrisa,
Harlan A. Pintoa,
J. Martin Browna and
Daniel M. Spielman
,a
a From the Lucas MRS Imaging Center (J.S.L., E.A., D.M.S.), Department of Radiology, the Department of Radiation Oncology/Division of Radiation Biology (M.F.A., J.M.B.), the Division of Otolaryngology/Head and Neck Surgery (D.J.T.), and the Department of Veterans Affairs Palo Alto Health Care System and Oncology Division Department of Medicine (H.A.P.), Stanford University, Stanford, CA.
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FIG 1. Dual BASING with PRESS excitation. The two BASING pulses (RFB1 and RFB1) are separated in time by TE = 2 msec. For Cycle 1, the Lac methine quartet is included in the BASING inversion band, whereas for Cycle 2, the BASING center frequency is shifted downfield to exclude all metabolites of interest. The addition of Cycle 1 and Cycle 2 spectra yields the singlets, whereas the subtraction of Cycle 2 from Cycle 1 yields the Lac methyl doublet
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FIG 2. Data from a representative hypoxic node in patient 7.
A, T2-weighted image (3000/85/2) shows the location of the PRESS box.
B, Histogram of oxygenation measurements. The median pO2 value is 1.3 mm Hg, which is very suggestive of hypoxia.
C, Uncoupled (Cycle 1 + Cycle 2).
D, Coupled (Cycle 1—Cycle 2).
E, Error spectra acquired with MRS parameters of 2000/144/256. The Cho:Cr ratio is 1.3.
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FIG 3. Data from a hypoxic node in patient 1.
A, T2-weighted image (3000/85/2) shows the location of the PRESS box.
B, Histogram of oxygen measurements. The median pO2 value is 0.7 mm Hg.
C, Uncoupled (Cycle 1 + Cycle 2).
D, Coupled (Cycle 1—Cycle 2).
E, Error spectra acquired with MRS parameters of 2000/144/256. The Cho:Cr ratio is 4.3.
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FIG 4. Data from a more aerobic node in patient 2.
A, T2-weighted image (3000/85/2) shows the location of the PRESS box.
B, Histogram of oxygen measurements. The median pO2 value is 14.1 mm Hg, which is more aerobic than the median values for patients 1 and 7.
C, Uncoupled (Cycle 1 + Cycle 2).
D, Coupled (Cycle 1—Cycle 2).
E, Error spectra acquired with MRS parameters of 2000/144/256. The Cho:Cr ratio is 3.9.
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FIG 5. Representative muscle spectrum.
A, T1-weighted image (500/8/2) from a normal volunteer shows the location of the PRESS box enclosing muscle tissue.
B, Uncoupled (Cycle 1 + Cycle 2).
C, Coupled (Cycle 1—Cycle 2).
D, Error spectra acquired with MRS parameters of 2000/144/256. The Cho:Cr ratio is 0.48, and the lipid suppression factor is greater than 3000.
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FIG 6. Accumulated Lac measurements.
A, Scatter plot of Lac SI versus pO2. The error bars are the SD after including the computed error signal (see fig 2C). A linear fit yielded a Pearson's correlation coefficient of -0.74.
B, Scatter plot of Lac/H2O versus pO2. The Pearson's coefficient is -0.76. The average water signal was used for normalizing the three samples with darkened boxes.
C, Box and whiskers plot for three data groups: pO2 < 10 mm Hg, pO2  10 mm Hg, and muscle. All three groups are statistically different (P < 0.05). The mean values for each group are annotated (0.60, 0.28, -0.05). The boxes span the range of Lac signal intensities from the 25th to 75th percentiles. The bars within the boxes denote the median value, whereas the vertical lines ("whiskers") are reflective of the data range.
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FIG 7. Accumulated Cho and Cr measurements.
A, Scatter plots of Cho SI versus pO2.
B, Scatter plots of Cho/H2O SI versus pO2. The correlation coefficients are -0.43 and-0.45, respectively. The average water signal was used for normalizing the three samples darkened black boxes.
C, Box and whiskers plots of Cho SI for three data groups: pO2 < 10 mm Hg, pO2 10 mm Hg, and muscle. The mean Cho values are annotated, and the data were not statistically different.
D, Box and whiskers plots of Cho:Cr ratios show statistically significant differentiation between muscle and cancer. The mean values are annotated.
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