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Comparative Study of Voxel-Based Epileptic Foci Localization Accuracy between Statistical Parametric Mapping and Three-dimensional Stereotactic Surface Projection

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Fluorine-18-fluorodeoxyglucose positron-emission tomography (18F-FDG-PET) is widely used to help localize the hypometabolic epileptogenic focus for presurgical evaluation of drug-refractory epilepsy patients. Two voxel-based brain mapping methods to interpret 18F-FDG-PET, statistical parametric mapping (SPM) and three-dimensional stereotactic surface projection (3D-SSP), improve the detection rate of seizure foci. This study aimed to compare the consistency of epileptic focus detection between SPM and 3D-SSP for 18F-FDG-PET brain mapping analysis.

Methods: We retrospectively reviewed the clinical, electroecephalographic, and brain imaging results of 35 patients with refractory epilepsy. 18F-FDG-PET studies were revaluated by SPM, 3D-SSP, and visual assessment, and the results were compared to the magnetic resonance imaging (MRI) lesion location and to the presumed epileptogenic zone (PEZ) defined by video-electroencephalogram and other clinical data. A second consistency study compared PET analyses to histopathology and surgical outcomes in the 19 patients who underwent lesion resection surgery.

Results: Of the 35 patients, consistency with the PEZ was 29/35 for SPM, 25/35 for 3D-SSP, 14/35 for visual assessment, and 10/35 for MRI. Concordance rates with the PEZ were significantly higher for SPM and 3D-SSP than for MRI (P < 0.05) and visual assessment (P < 0.05). Differences between SPM and 3D-SSP and between visual assessment and MRI were not significant. In the 19 surgical patients, concordance with histopathology/clinical outcome was 14/19 for SPM, 15/19 for 3D-SSP, 14/19 for visual assessment, and 9/19 for MRI (P > 0.05). A favorable Engel outcome (class I/II) was found in 16 of 19 cases (84%), and failure of seizure control was found in 3 of 19 patients (class III/IV).

Conclusion: Voxel-based 18F-FDG-PET brain mapping analysis using SPM or 3D-SSP can improve the detection rate of the epileptic focus compared to visual assessment and MRI. Consistency with PEZ was similar between SPM and 3D-SSP; according to their own characteristics, 3D-SSP is recommended for primary evaluation due to greater efficiency and operability of the software, while SPM is recommended for high-accuracy localization of complex lesions. Therefore, joint application of both software packages may be the best solution for FDG-PET analysis of epileptic focus localization.

No MeSH data available.


Comparison of location concordance relative to PEZ among analysis methods (**P < 0.05, ##P > 0.05).
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Figure 2: Comparison of location concordance relative to PEZ among analysis methods (**P < 0.05, ##P > 0.05).

Mentions: The concordance rate with PEZ was significantly higher using computational analyses of PET compared to MRI (SPM-PET: 83 vs. 29%, P = 0.000, k = −0.115; 3D-SSP-PET: 71 vs. 29%, P = 0.001, k = −0.014), while the difference between visual-PET and MRI was not significant (40 vs. 29%, P = 0.388, k = 0.25), as shown in Figure 2. Combined SPM-PET and 3D-SSP-PET results were consistent with PEZ in 32 of 35 cases (91%), while combining computational analysis with visual-PET increased consistency with PEZ to 34 of 35 cases, significantly higher than for MRI (97 vs. 26%, P = 0.000, k = −0.058) (Figure 3). Indeed, MRI failed to reveal the epileptogenic lesion according to PEZ in 25 of 35 patients (71%). Within this NS group, SPM-PET successfully localized the PEZ-defined lesion in 22 of 25 cases (88%) and 3D-SSP-PET in 18 of 25 cases (72%), while visual-PET was consistent with PEZ in only 8 of these 25 cases (32%).


Comparative Study of Voxel-Based Epileptic Foci Localization Accuracy between Statistical Parametric Mapping and Three-dimensional Stereotactic Surface Projection
Comparison of location concordance relative to PEZ among analysis methods (**P < 0.05, ##P > 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037321&req=5

Figure 2: Comparison of location concordance relative to PEZ among analysis methods (**P < 0.05, ##P > 0.05).
Mentions: The concordance rate with PEZ was significantly higher using computational analyses of PET compared to MRI (SPM-PET: 83 vs. 29%, P = 0.000, k = −0.115; 3D-SSP-PET: 71 vs. 29%, P = 0.001, k = −0.014), while the difference between visual-PET and MRI was not significant (40 vs. 29%, P = 0.388, k = 0.25), as shown in Figure 2. Combined SPM-PET and 3D-SSP-PET results were consistent with PEZ in 32 of 35 cases (91%), while combining computational analysis with visual-PET increased consistency with PEZ to 34 of 35 cases, significantly higher than for MRI (97 vs. 26%, P = 0.000, k = −0.058) (Figure 3). Indeed, MRI failed to reveal the epileptogenic lesion according to PEZ in 25 of 35 patients (71%). Within this NS group, SPM-PET successfully localized the PEZ-defined lesion in 22 of 25 cases (88%) and 3D-SSP-PET in 18 of 25 cases (72%), while visual-PET was consistent with PEZ in only 8 of these 25 cases (32%).

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Fluorine-18-fluorodeoxyglucose positron-emission tomography (18F-FDG-PET) is widely used to help localize the hypometabolic epileptogenic focus for presurgical evaluation of drug-refractory epilepsy patients. Two voxel-based brain mapping methods to interpret 18F-FDG-PET, statistical parametric mapping (SPM) and three-dimensional stereotactic surface projection (3D-SSP), improve the detection rate of seizure foci. This study aimed to compare the consistency of epileptic focus detection between SPM and 3D-SSP for 18F-FDG-PET brain mapping analysis.

Methods: We retrospectively reviewed the clinical, electroecephalographic, and brain imaging results of 35 patients with refractory epilepsy. 18F-FDG-PET studies were revaluated by SPM, 3D-SSP, and visual assessment, and the results were compared to the magnetic resonance imaging (MRI) lesion location and to the presumed epileptogenic zone (PEZ) defined by video-electroencephalogram and other clinical data. A second consistency study compared PET analyses to histopathology and surgical outcomes in the 19 patients who underwent lesion resection surgery.

Results: Of the 35 patients, consistency with the PEZ was 29/35 for SPM, 25/35 for 3D-SSP, 14/35 for visual assessment, and 10/35 for MRI. Concordance rates with the PEZ were significantly higher for SPM and 3D-SSP than for MRI (P&thinsp;&lt;&thinsp;0.05) and visual assessment (P&thinsp;&lt;&thinsp;0.05). Differences between SPM and 3D-SSP and between visual assessment and MRI were not significant. In the 19 surgical patients, concordance with histopathology/clinical outcome was 14/19 for SPM, 15/19 for 3D-SSP, 14/19 for visual assessment, and 9/19 for MRI (P&thinsp;&gt;&thinsp;0.05). A favorable Engel outcome (class I/II) was found in 16 of 19 cases (84%), and failure of seizure control was found in 3 of 19 patients (class III/IV).

Conclusion: Voxel-based 18F-FDG-PET brain mapping analysis using SPM or 3D-SSP can improve the detection rate of the epileptic focus compared to visual assessment and MRI. Consistency with PEZ was similar between SPM and 3D-SSP; according to their own characteristics, 3D-SSP is recommended for primary evaluation due to greater efficiency and operability of the software, while SPM is recommended for high-accuracy localization of complex lesions. Therefore, joint application of both software packages may be the best solution for FDG-PET analysis of epileptic focus localization.

No MeSH data available.