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Metabolic alterations in Parkinson's disease after thalamotomy, as revealed by 1H MR spectroscopy.

Baik HM, Choe BY, Lee HK, Suh TS, Son BC, Lee JM - Korean J Radiol (2002 Jul-Sep)

Bottom Line: In the substantia nigra of 80% of patients (12/15) who showed clinical improvement, decreased NAA/Cho ratios were observed in selected voxels after thalamic surgery (p < 0.05).In the thalamus of 67% of such patients (10/15), significant decreases were also noted (p < 0.05).Our results suggest that the NAA/Cho ratio may be a valuable criterion for the evaluation of Parkinson's disease patients who show clinical improvement following surgery.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Kangnam St. Mary's Hospital College of Medicine, The Catholic University of Korea, Seoul, Korea.

ABSTRACT

Objective: To determine, using proton magnetic resonance spectroscopy (1H MRS) whether thalamotomy in patients with Parkinson's disease gives rise to significant changes in regional brain metabolism.

Materials and methods: Fifteen patients each underwent stereotactic thalamotomy for the control of medically refractory parkinsonian tremor. Single-voxel 1H MRS was performed on a 1.5T unit using a STEAM sequence (TR/TM/TE, 2000/14/20 msec), and spectra were obtained from substantia nigra, thalamus and putamen areas, with volumes of interest of 7-8 ml, before and after thalamotomy. NAA/Cho, NAA/Cr and Cho/Cr metabolite ratios were calculated from relative peak area measurements, and any changes were recorded and assessed.

Results: In the substantia nigra and thalamus, NAA/Cho ratios were generally low. In the substantia nigra of 80% of patients (12/15) who showed clinical improvement, decreased NAA/Cho ratios were observed in selected voxels after thalamic surgery (p < 0.05). In the thalamus of 67% of such patients (10/15), significant decreases were also noted (p < 0.05).

Conclusion: Our results suggest that the NAA/Cho ratio may be a valuable criterion for the evaluation of Parkinson's disease patients who show clinical improvement following surgery. By highlighting variations in this ratio, 1H MRS may help lead to a better understanding of the pathophysiologic processes occurring in those with Parkinson's disease.

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Related in: MedlinePlus

Typical T2-weighted axial MR images obtained approximately 4 months after stereotactic thalamotomy show no apparent morphologic abnormalities. Voxels of (A) substantia nigra, (B) thalamus, and (C) putamen of the hemisphere that did undergo surgery were selected for localized in-vivo 1H magnetic resonance spectroscopy.
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Figure 1: Typical T2-weighted axial MR images obtained approximately 4 months after stereotactic thalamotomy show no apparent morphologic abnormalities. Voxels of (A) substantia nigra, (B) thalamus, and (C) putamen of the hemisphere that did undergo surgery were selected for localized in-vivo 1H magnetic resonance spectroscopy.

Mentions: During the initial postoperative period of about one week, each patient underwent T2-weighted MR imaging, and temporary neurological deficits, presumably due to perilesional edema, were observed in all cases. The deficits resolved as the edema resolved, and were absent at four-month follow-up examination (Fig. 1B). Typical T2-weighted axial MR images, including voxels of the substantia nigra, thalamus and putamen for localized in-vivo 1H MRS after thalamotomy, are shown in Figure 1. In-vivo 1H MR spectra were also obtained from the voxels of the substantia nigra, thalamus and putamen, on the most affected side, before and after thalamotomy (Fig. 2). NAA/Cho ratios for the substantia nigra, thalamus and putamen are listed in Table 2, and compared graphically in Figure 3. As can be seen in Figures 3A and 3B, the differences between them are substantial. In the substantia nigra of 80% of patients (12/15) who showed clinical improvement following thalamotomy, decreased NAA/Cho ratios were observed at selected voxels, and significant metabolic changes in these ratios were apparent after thalamic surgery (p = 0.03). In 67% of patients (10/15) whose clinical condition improved, these ratios were also significantly lower in the thalamus (p = 0.03). In the putamen, significant statistical change in the ratios was not established (p = 0.08), though a significant reduction was noted in 73% of patients (11/15). Thus, in these 15 cases, NAA/Cho ratios in the substantia nigra, thalamus and putamen were generally low following thalamotomy. No significant changes in other metabolite ratios (NAA/Cr and Cho/Cr) were established. Although the mean ratios appear to indicate lower NAA/Cho for patients than for age-matched controls, t tests showed that these differences were not statistically significant.


Metabolic alterations in Parkinson's disease after thalamotomy, as revealed by 1H MR spectroscopy.

Baik HM, Choe BY, Lee HK, Suh TS, Son BC, Lee JM - Korean J Radiol (2002 Jul-Sep)

Typical T2-weighted axial MR images obtained approximately 4 months after stereotactic thalamotomy show no apparent morphologic abnormalities. Voxels of (A) substantia nigra, (B) thalamus, and (C) putamen of the hemisphere that did undergo surgery were selected for localized in-vivo 1H magnetic resonance spectroscopy.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2713882&req=5

Figure 1: Typical T2-weighted axial MR images obtained approximately 4 months after stereotactic thalamotomy show no apparent morphologic abnormalities. Voxels of (A) substantia nigra, (B) thalamus, and (C) putamen of the hemisphere that did undergo surgery were selected for localized in-vivo 1H magnetic resonance spectroscopy.
Mentions: During the initial postoperative period of about one week, each patient underwent T2-weighted MR imaging, and temporary neurological deficits, presumably due to perilesional edema, were observed in all cases. The deficits resolved as the edema resolved, and were absent at four-month follow-up examination (Fig. 1B). Typical T2-weighted axial MR images, including voxels of the substantia nigra, thalamus and putamen for localized in-vivo 1H MRS after thalamotomy, are shown in Figure 1. In-vivo 1H MR spectra were also obtained from the voxels of the substantia nigra, thalamus and putamen, on the most affected side, before and after thalamotomy (Fig. 2). NAA/Cho ratios for the substantia nigra, thalamus and putamen are listed in Table 2, and compared graphically in Figure 3. As can be seen in Figures 3A and 3B, the differences between them are substantial. In the substantia nigra of 80% of patients (12/15) who showed clinical improvement following thalamotomy, decreased NAA/Cho ratios were observed at selected voxels, and significant metabolic changes in these ratios were apparent after thalamic surgery (p = 0.03). In 67% of patients (10/15) whose clinical condition improved, these ratios were also significantly lower in the thalamus (p = 0.03). In the putamen, significant statistical change in the ratios was not established (p = 0.08), though a significant reduction was noted in 73% of patients (11/15). Thus, in these 15 cases, NAA/Cho ratios in the substantia nigra, thalamus and putamen were generally low following thalamotomy. No significant changes in other metabolite ratios (NAA/Cr and Cho/Cr) were established. Although the mean ratios appear to indicate lower NAA/Cho for patients than for age-matched controls, t tests showed that these differences were not statistically significant.

Bottom Line: In the substantia nigra of 80% of patients (12/15) who showed clinical improvement, decreased NAA/Cho ratios were observed in selected voxels after thalamic surgery (p < 0.05).In the thalamus of 67% of such patients (10/15), significant decreases were also noted (p < 0.05).Our results suggest that the NAA/Cho ratio may be a valuable criterion for the evaluation of Parkinson's disease patients who show clinical improvement following surgery.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Kangnam St. Mary's Hospital College of Medicine, The Catholic University of Korea, Seoul, Korea.

ABSTRACT

Objective: To determine, using proton magnetic resonance spectroscopy (1H MRS) whether thalamotomy in patients with Parkinson's disease gives rise to significant changes in regional brain metabolism.

Materials and methods: Fifteen patients each underwent stereotactic thalamotomy for the control of medically refractory parkinsonian tremor. Single-voxel 1H MRS was performed on a 1.5T unit using a STEAM sequence (TR/TM/TE, 2000/14/20 msec), and spectra were obtained from substantia nigra, thalamus and putamen areas, with volumes of interest of 7-8 ml, before and after thalamotomy. NAA/Cho, NAA/Cr and Cho/Cr metabolite ratios were calculated from relative peak area measurements, and any changes were recorded and assessed.

Results: In the substantia nigra and thalamus, NAA/Cho ratios were generally low. In the substantia nigra of 80% of patients (12/15) who showed clinical improvement, decreased NAA/Cho ratios were observed in selected voxels after thalamic surgery (p < 0.05). In the thalamus of 67% of such patients (10/15), significant decreases were also noted (p < 0.05).

Conclusion: Our results suggest that the NAA/Cho ratio may be a valuable criterion for the evaluation of Parkinson's disease patients who show clinical improvement following surgery. By highlighting variations in this ratio, 1H MRS may help lead to a better understanding of the pathophysiologic processes occurring in those with Parkinson's disease.

Show MeSH
Related in: MedlinePlus