Early Changes In Proton Magnetic Resonance Spectroscopic Findings In Patients Receiving Three-stage Gkrs For Relatively Large Brain Metastatic TumorsKeywords: Imaging, brain metastasis, magnetic resonance imaging, gamma knife, radiosurgeryInteractive Manuscript
Ask Questions of this Manuscript:
What is the background behind your study?
The response to tumor radiosurgery is evaluated with imaging.
What is the purpose of your study?
We studied early changes on proton magnetic resonance spectroscopy (1H-MRS) in patients who underwent three-stage gamma knife radiosurgery (GKRS) for relatively large metastatic brain tumors.
Describe your patient group.
Among 45 brain metastasis patients who underwent three-stage GKRS with an interval of two weeks from 2005 to 2009, 13 (eight men, five women, mean age 62 range; 42-81 years) were selected for this study.
Describe what you did.
All 13 patients (13 tumors) were assessed using multi-voxel 1H-MRS at least twice, before the first and third sessions. Seven patients received follow-up 1H-MRS studies at a median interval of 31 (range; 4-84) weeks. The most common primary tumor site was the lung, 10 patients, followed by breast, esophagus and thymus in one each. The mean pre-GKRS tumor volume was 20.7 (range; 9.9-30.8) cc. A 10 Gy peripheral dose was given in each of three sessions. We analyzed 1H-MRS-shown metabolites using a total of 113 voxels of which more than 60% of individual voxel volume was accounted for by a solid tumor component.
Describe your main findings.
Remarkable tumor volume reduction was seen between the first (mean; 20.7 cc) and third (mean; 9.5 cc) sessions. The volume reduction rate was 47.2%. The mean choline peak value before the first session (2.55+2.45) decreased significantly as compared to that before the third session (1.18+1.00, P<0.01) while there were no significant differences in metabolite peak values of N-acetyl-aspartate and creatine between the two sessions. Eight patients showed post-treatment tumor volume reductions while there were no remarkable changes in three. Due to early death, the other two patients did not receive follow-up MR examinations. In the seven patients assessed using 1HMRS after treatment, no marked changes in metabolite peak values were detected.
Describe the main limitation of this study.
This is a retrospective study.
Describe your main conclusion.
Three-stage GKRS produced remarkable tumor volume reduction during the four-week period between the first and third sessions in all cases and there was a subsequent post-treatment decrease in some cases.
Describe the importance of your findings and how they can be used by others.
While choline peak values had decreased remarkably by the third session, thereafter, little change was seen.
The response to tumor radiosurgery is evaluated with imaging.
We studied early changes on proton magnetic resonance spectroscopy (1H-MRS) in patients who underwent three-stage gamma knife radiosurgery (GKRS) for relatively large metastatic brain tumors.
Among 45 brain metastasis patients who underwent three-stage GKRS with an interval of two weeks from 2005 to 2009, 13 (eight men, five women, mean age 62 range; 42-81 years) were selected for this study.
All 13 patients (13 tumors) were assessed using multi-voxel 1H-MRS at least twice, before the first and third sessions. Seven patients received follow-up 1H-MRS studies at a median interval of 31 (range; 4-84) weeks. The most common primary tumor site was the lung, 10 patients, followed by breast, esophagus and thymus in one each. The mean pre-GKRS tumor volume was 20.7 (range; 9.9-30.8) cc. A 10 Gy peripheral dose was given in each of three sessions. We analyzed 1H-MRS-shown metabolites using a total of 113 voxels of which more than 60% of individual voxel volume was accounted for by a solid tumor component.
Remarkable tumor volume reduction was seen between the first (mean; 20.7 cc) and third (mean; 9.5 cc) sessions. The volume reduction rate was 47.2%. The mean choline peak value before the first session (2.55+2.45) decreased significantly as compared to that before the third session (1.18+1.00, P<0.01) while there were no significant differences in metabolite peak values of N-acetyl-aspartate and creatine between the two sessions. Eight patients showed post-treatment tumor volume reductions while there were no remarkable changes in three. Due to early death, the other two patients did not receive follow-up MR examinations. In the seven patients assessed using 1HMRS after treatment, no marked changes in metabolite peak values were detected.
This is a retrospective study.
Three-stage GKRS produced remarkable tumor volume reduction during the four-week period between the first and third sessions in all cases and there was a subsequent post-treatment decrease in some cases.
While choline peak values had decreased remarkably by the third session, thereafter, little change was seen.
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