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The effects of voxel localization and time of echo on the diagnostic accuracy of cystic brain tumors in 3 tesla magnetic resonance spectroscopy.

Rezvanizadeh A, Firouznia K, Salehi-Sadaghiani M, Mohseni M, Gharaei D, Ghanaati H, Saligheh Rad H, Masoudnia M - Iran J Radiol (2012)

Bottom Line: There was no statistically significant difference among the compared TEs.The percentages of ratios above the cut-off point at all TEs were more in the rim compared to the center and in the union of both compared to the rim or center.If not accessible, the use of the union of peripheral and central voxels enhances the sensitivity when compared to usage of peripheral or central voxels solely.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

ABSTRACT

Background: Although magnetic resonance spectroscopy (MRS) has been shown as an effective diagnostic tool in distinguishing inflammation from neoplasm in cystic brain lesions, the optimum approach in selecting the portions of lesions in MRS and the possible effects of different times of echoes (TEs) remains unknown.

Objectives: To determine the most effective TE in diagnosing neoplastic lesions based on detecting choline (Cho), N acetyl aspartate (NAA) and creatinine (Cr). Moreover, the role of voxel localization on the diagnosis of the neoplastic nature of the lesions is assessed through comparing the abovementioned metabolite ratios in the rim and center of each lesion with the same TE.

Patients and methods: In 16 patients with brain cystic tumors, MRS was performed at TEs of 30, 135 and 270 ms for detection of Cho, NAA and Cr metabolites using a 3 tesla MRI unit. The percentage of analyzed ratios greater than a cut-off point of 1.3 for Cho/Cr and 1.6 for Cho/NAA were calculated.

Results: Cho/Cr and Cho/NAA ratio means at all TEs were more at the central area in comparison with the periphery, although none of the differences were statistically significant. There was no statistically significant difference among the compared TEs. The percentages of ratios above the cut-off point at all TEs were more in the rim compared to the center and in the union of both compared to the rim or center. All the patients had at least one voxel with a Cho/Cr ratio of more than 1.3 when the voxel was chosen according to the hotspots shown in the chemical shift imaging map, regardless of their location at all examined TEs.

Conclusions: Selection of voxels with the guide of chemical shift imaging map yields to 100% diagnostic sensitivity. If not accessible, the use of the union of peripheral and central voxels enhances the sensitivity when compared to usage of peripheral or central voxels solely.

No MeSH data available.


Related in: MedlinePlus

Comparing the effect of different TEs on the analyzed metabolite ratios. Each triple column represents a specific location. The color of ratios corresponds to the TE. The height of bars represents mean.
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fig939: Comparing the effect of different TEs on the analyzed metabolite ratios. Each triple column represents a specific location. The color of ratios corresponds to the TE. The height of bars represents mean.

Mentions: Of the 16 patients, 10 (62.5 %) had glioblastoma multiform (WHO grade IV) based on postoperative pathologic specimens reviewed by an experienced neuro-pathologist. One (6.25%) pilocytic astrocytoma, one (6.25%) oligodendroglioma (WHO grade I), two (12.5%) anaplastic astrocytoma (WHO grade III) and two (12.5%) metastases were also reported. The metabolite peak amplitude of Cho, NAA and Cr were analyzed. The Cho/Cr and Cho/NAA ratios for the rim and the center of the cystic tumors were computed separately for TE = 30, 135 and 270 ms (Figure 1). In order to investigate the role of the voxel location on the resulting ratios, the associated ratios of the rim and the center of the tumors were compared. As demonstrated in Figure 1, the Cho/Cr and Cho/NAA ratio means at all TEs were more at the central area, although none of the differences were statistically significant (Figure 1). Furthermore, in order to assess the effect of TE, the abovementioned ratios were compared in different TEs (Figure 2). There was no statistically significant difference among the compared TEs.


The effects of voxel localization and time of echo on the diagnostic accuracy of cystic brain tumors in 3 tesla magnetic resonance spectroscopy.

Rezvanizadeh A, Firouznia K, Salehi-Sadaghiani M, Mohseni M, Gharaei D, Ghanaati H, Saligheh Rad H, Masoudnia M - Iran J Radiol (2012)

Comparing the effect of different TEs on the analyzed metabolite ratios. Each triple column represents a specific location. The color of ratios corresponds to the TE. The height of bars represents mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3569551&req=5

fig939: Comparing the effect of different TEs on the analyzed metabolite ratios. Each triple column represents a specific location. The color of ratios corresponds to the TE. The height of bars represents mean.
Mentions: Of the 16 patients, 10 (62.5 %) had glioblastoma multiform (WHO grade IV) based on postoperative pathologic specimens reviewed by an experienced neuro-pathologist. One (6.25%) pilocytic astrocytoma, one (6.25%) oligodendroglioma (WHO grade I), two (12.5%) anaplastic astrocytoma (WHO grade III) and two (12.5%) metastases were also reported. The metabolite peak amplitude of Cho, NAA and Cr were analyzed. The Cho/Cr and Cho/NAA ratios for the rim and the center of the cystic tumors were computed separately for TE = 30, 135 and 270 ms (Figure 1). In order to investigate the role of the voxel location on the resulting ratios, the associated ratios of the rim and the center of the tumors were compared. As demonstrated in Figure 1, the Cho/Cr and Cho/NAA ratio means at all TEs were more at the central area, although none of the differences were statistically significant (Figure 1). Furthermore, in order to assess the effect of TE, the abovementioned ratios were compared in different TEs (Figure 2). There was no statistically significant difference among the compared TEs.

Bottom Line: There was no statistically significant difference among the compared TEs.The percentages of ratios above the cut-off point at all TEs were more in the rim compared to the center and in the union of both compared to the rim or center.If not accessible, the use of the union of peripheral and central voxels enhances the sensitivity when compared to usage of peripheral or central voxels solely.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

ABSTRACT

Background: Although magnetic resonance spectroscopy (MRS) has been shown as an effective diagnostic tool in distinguishing inflammation from neoplasm in cystic brain lesions, the optimum approach in selecting the portions of lesions in MRS and the possible effects of different times of echoes (TEs) remains unknown.

Objectives: To determine the most effective TE in diagnosing neoplastic lesions based on detecting choline (Cho), N acetyl aspartate (NAA) and creatinine (Cr). Moreover, the role of voxel localization on the diagnosis of the neoplastic nature of the lesions is assessed through comparing the abovementioned metabolite ratios in the rim and center of each lesion with the same TE.

Patients and methods: In 16 patients with brain cystic tumors, MRS was performed at TEs of 30, 135 and 270 ms for detection of Cho, NAA and Cr metabolites using a 3 tesla MRI unit. The percentage of analyzed ratios greater than a cut-off point of 1.3 for Cho/Cr and 1.6 for Cho/NAA were calculated.

Results: Cho/Cr and Cho/NAA ratio means at all TEs were more at the central area in comparison with the periphery, although none of the differences were statistically significant. There was no statistically significant difference among the compared TEs. The percentages of ratios above the cut-off point at all TEs were more in the rim compared to the center and in the union of both compared to the rim or center. All the patients had at least one voxel with a Cho/Cr ratio of more than 1.3 when the voxel was chosen according to the hotspots shown in the chemical shift imaging map, regardless of their location at all examined TEs.

Conclusions: Selection of voxels with the guide of chemical shift imaging map yields to 100% diagnostic sensitivity. If not accessible, the use of the union of peripheral and central voxels enhances the sensitivity when compared to usage of peripheral or central voxels solely.

No MeSH data available.


Related in: MedlinePlus