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Age-related changes in conventional and magnetization transfer MR imaging in elderly people: comparison with neurocognitive performance.

Lee KY, Kim TK, Park M, Ko S, Song IC, Cho IH - Korean J Radiol (2004 Apr-Jun)

Bottom Line: The T2LV scores were significantly higher in the cognitively impaired subjects (p = 0.01).An inverse correlation was found between the PHMTR and T2LV (r = -0.747, p < 0.001), and also between the PBV and T2LV (r = -0.823, p < 0.001).Our findings of a correlation among the PBV, the T2LV, and the PHMTR suggest that MTR histograms and the PBV and T2LV can be used as a reliable method and valid statistical tool, respectively, for quantifying the total lesion burden in an aging brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Korea University College of Medicine, Seoul, Korea. tkkim@kumc.or.kr

ABSTRACT

Objective: This study was designed to compare three different measures of the elderly human brain; the magnetization transfer ratio (MTR) histogram, the percentage of brain parenchymal volume, and the volume of T2 hyperintense areas in terms of correlations with the study subjects neurocognitive performance.

Materials and methods: Thirty-five healthy community-dwelling elderly volunteers aged 60-82 years underwent dual fast spin-echo (FSE) imaging and magnetization transfer imaging. A semi-automated technique was used to generate the MTR histogram, the brain parenchymal volume, and the T2 lesion volume. The subjects' neurocognitive performance was assessed by using the Korean-Mini Mental State Examination (K-MMSE) and additional tests. The peak height of the MTR (PHMTR), the percentage of brain parenchymal volume (PBV), and the normalized T2 lesion volume (T2LV) were compared between the normal group (Z score on the K-MMSE>/=-2, n=23) and the mild cognitive impairment group (Z score on the K-MMSE < -2, n=12), and these parameters were correlated with age and various neurocognitive performance scores.

Results: The PHMTR was significantly lower in the cognitively impaired subjects than the PHMTR in the normal subjects (p = 0.005). The PBV scores were lower in the cognitively impaired subjects than in the normal subjects (p = 0.02). The T2LV scores were significantly higher in the cognitively impaired subjects (p = 0.01). An inverse correlation was found between the PHMTR and T2LV (r = -0.747, p < 0.001), and also between the PBV and T2LV (r = -0.823, p < 0.001). A positive correlation was observed between the PHMTR and the PBV (r = 0.846, p < 0.001). Scores on the various neurocognitive tests were positively correlated with the PHMTR (6 of 7 items) and the PBV (5 of 7 items), and they were negatively correlated with the T2LV (5 of 7 items).

Conclusion: Our findings of a correlation among the PBV, the T2LV, and the PHMTR suggest that MTR histograms and the PBV and T2LV can be used as a reliable method and valid statistical tool, respectively, for quantifying the total lesion burden in an aging brain.

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Related in: MedlinePlus

Segmented volume image of the intracranium (A), cerebrospinal fluid (B), and brain parenchyma (C) from proton density-weighted and T2-weighted images.
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Figure 1: Segmented volume image of the intracranium (A), cerebrospinal fluid (B), and brain parenchyma (C) from proton density-weighted and T2-weighted images.

Mentions: T2 lesion volume calculations were performed with a validated semiautomatic computerized method based on the concept of fuzzy connectedness (12) by using PD- and T2-weighted image sets. This method has been described previously and validated in several studies (12-14). Parenchyma and CSF volumes also were determined with the same system (Fig. 1). To summarize, PD- and T2-weighted images were used for segmentation as follows: the skull was stripped from the images, and the whole brain was segmented into CSF and parenchyma using a k-means cluster analysis (15). Manual editing to exclude any residual extracranial components followed this automated process. To normalize for baseline differences in the intracranial volumes among subjects, an additional parameter, the PBV (%), was calculated by dividing the brain parenchymal volume by the sum of the brain parenchymal volume and CSF volume. Another parameter, the T2LV (%), also was achieved by dividing the T2 lesion volume by the brain parenchymal volume for interpersonal normalization.


Age-related changes in conventional and magnetization transfer MR imaging in elderly people: comparison with neurocognitive performance.

Lee KY, Kim TK, Park M, Ko S, Song IC, Cho IH - Korean J Radiol (2004 Apr-Jun)

Segmented volume image of the intracranium (A), cerebrospinal fluid (B), and brain parenchyma (C) from proton density-weighted and T2-weighted images.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2698146&req=5

Figure 1: Segmented volume image of the intracranium (A), cerebrospinal fluid (B), and brain parenchyma (C) from proton density-weighted and T2-weighted images.
Mentions: T2 lesion volume calculations were performed with a validated semiautomatic computerized method based on the concept of fuzzy connectedness (12) by using PD- and T2-weighted image sets. This method has been described previously and validated in several studies (12-14). Parenchyma and CSF volumes also were determined with the same system (Fig. 1). To summarize, PD- and T2-weighted images were used for segmentation as follows: the skull was stripped from the images, and the whole brain was segmented into CSF and parenchyma using a k-means cluster analysis (15). Manual editing to exclude any residual extracranial components followed this automated process. To normalize for baseline differences in the intracranial volumes among subjects, an additional parameter, the PBV (%), was calculated by dividing the brain parenchymal volume by the sum of the brain parenchymal volume and CSF volume. Another parameter, the T2LV (%), also was achieved by dividing the T2 lesion volume by the brain parenchymal volume for interpersonal normalization.

Bottom Line: The T2LV scores were significantly higher in the cognitively impaired subjects (p = 0.01).An inverse correlation was found between the PHMTR and T2LV (r = -0.747, p < 0.001), and also between the PBV and T2LV (r = -0.823, p < 0.001).Our findings of a correlation among the PBV, the T2LV, and the PHMTR suggest that MTR histograms and the PBV and T2LV can be used as a reliable method and valid statistical tool, respectively, for quantifying the total lesion burden in an aging brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Korea University College of Medicine, Seoul, Korea. tkkim@kumc.or.kr

ABSTRACT

Objective: This study was designed to compare three different measures of the elderly human brain; the magnetization transfer ratio (MTR) histogram, the percentage of brain parenchymal volume, and the volume of T2 hyperintense areas in terms of correlations with the study subjects neurocognitive performance.

Materials and methods: Thirty-five healthy community-dwelling elderly volunteers aged 60-82 years underwent dual fast spin-echo (FSE) imaging and magnetization transfer imaging. A semi-automated technique was used to generate the MTR histogram, the brain parenchymal volume, and the T2 lesion volume. The subjects' neurocognitive performance was assessed by using the Korean-Mini Mental State Examination (K-MMSE) and additional tests. The peak height of the MTR (PHMTR), the percentage of brain parenchymal volume (PBV), and the normalized T2 lesion volume (T2LV) were compared between the normal group (Z score on the K-MMSE>/=-2, n=23) and the mild cognitive impairment group (Z score on the K-MMSE < -2, n=12), and these parameters were correlated with age and various neurocognitive performance scores.

Results: The PHMTR was significantly lower in the cognitively impaired subjects than the PHMTR in the normal subjects (p = 0.005). The PBV scores were lower in the cognitively impaired subjects than in the normal subjects (p = 0.02). The T2LV scores were significantly higher in the cognitively impaired subjects (p = 0.01). An inverse correlation was found between the PHMTR and T2LV (r = -0.747, p < 0.001), and also between the PBV and T2LV (r = -0.823, p < 0.001). A positive correlation was observed between the PHMTR and the PBV (r = 0.846, p < 0.001). Scores on the various neurocognitive tests were positively correlated with the PHMTR (6 of 7 items) and the PBV (5 of 7 items), and they were negatively correlated with the T2LV (5 of 7 items).

Conclusion: Our findings of a correlation among the PBV, the T2LV, and the PHMTR suggest that MTR histograms and the PBV and T2LV can be used as a reliable method and valid statistical tool, respectively, for quantifying the total lesion burden in an aging brain.

Show MeSH
Related in: MedlinePlus