Yu Oyama

Kameda Medical Center, Kameda, Niigata, Japan

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Publications (3)7.26 Total impact

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    ABSTRACT: To assess the efficacy of quantitative (1)H MR spectroscopy (MRS) using the external standard method to predict the pathological response to neoadjuvant chemotherapy with an anthracycline-based regimen in breast cancer patients. Sixteen patients with breast cancer were included. Tumor response to chemotherapy was evaluated after the second cycle using MRI and MRS. Final histopathology following surgery after four cycles of chemotherapy served as reference. The average normalized choline (Cho) signal was 1.2 (range, 0.40 to 2.8). There were no significant differences in the baseline tumor size and normalized Cho signals between the pathological responders (n = 8) and nonresponders (n = 8). The reduction rates of the normalized Cho signal were statistically significantly different between the pathological responders and nonresponders (P = 0.004), whereas the reduction rates of the lesion size were not significantly different between the two groups. When 40-50% of the reduction rates of the normalized Cho was chosen as the cutoff value, the positive and negative predictive values of MRS were 89% (8/9) and 100% (7/7), respectively. The changes in Cho after the second cycle of chemotherapy as determined by quantitative MRS may be more sensitive than changes in the tumor size to predict the pathological response.
    Journal of Magnetic Resonance Imaging 04/2010; 31(4):895-902. DOI:10.1002/jmri.22118 · 3.21 Impact Factor
  • Mitsuhiro Tozaki · Yu Oyama · Eisuke Fukuma ·
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    ABSTRACT: The aim of this study was to assess the efficacy of single-voxel (1)H magnetic resonance spectroscopy (MRS) at 1.5 T to evaluate early responses to neoadjuvant chemotherapy after the first treatment in breast cancer patients and to compare it to measurements of apparent diffusion coefficient (ADC) values derived from diffusion-weighted magnetic resonance imaging (MRI). Nine patients with breast cancer who were scheduled to receive neoadjuvant chemotherapy were recruited. MR examination after the first cycle was scheduled for a few days before the administration of the second dose. Two patients were excluded from the study because their regimen was changed after the first cycle. MRS before chemotherapy demonstrated the presence of choline (Cho) at 3.22-3.23 ppm in six cases and at 3.27 ppm in one case. Diffusion-weighted MRI before chemotherapy demonstrated a localized high-signal lesion in all cases. The change of the integral value of Cho after the first cycle of chemotherapy showed a positive correlation with the change in lesion size (r = 0.91, P = 0.01), whereas no correlation was observed between the change of ADC values after the first cycle and the change in lesion size (r = 0.45, P = 0.32). MRS after the first cycle may be more sensitive to diffusion-weighted MRI to predict the pathological response.
    Japanese journal of radiology 02/2010; 28(2):101-9. DOI:10.1007/s11604-009-0391-7 · 0.84 Impact Factor
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    ABSTRACT: To assess the efficacy of (1)H MR spectroscopy (MRS) to evaluate early responses to neoadjuvant chemotherapy in breast cancer patients, as compared to that of the standardized uptake value (SUV) in (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). This retrospective study included seven patients with breast cancer who had both single-voxel (1)H MRS and PET/computed tomography (CT) acquired before, during, and after neoadjuvant chemotherapy. The averages of the Choline (Cho) integral value and peak SUV before chemotherapy were 2.5 (range, 1.2-5.3) and 7.5 (range, 1.9-19), respectively. Three cases became negative for both Cho and peak SUV after two cycles of chemotherapy, and one patient became negative before surgery. In the remaining three patients, the curves of both values paralleled the time course of chemotherapy treatment. The difference between Cho and peak SUV before, during, and after chemotherapy was r = 0.65 (P = 0.12), r = 0.80 (P = 0.03), and r = 0.99 (P < 0.001), respectively. The reduction rate (RR) of both values after chemotherapy was also correlated (r = 0.84, P = 0.02). A change in the Cho integral value is well correlated with that of peak SUV in the time course of neoadjuvant chemotherapy; thus, breast (1)H MRS is thought to be an alternative to sequential (18)F-FDG PET.
    Journal of Magnetic Resonance Imaging 08/2008; 28(2):420-7. DOI:10.1002/jmri.21454 · 3.21 Impact Factor