Article Figures & Data
Figures
- FIGURE 1.
Method of determining area of hypoperfused region extracted from patient data to brain surface from area of trapezoidal shape. We calculated distance (r1; mm) of hypoperfused lesion and distance (r2; mm) of next slice using slice thickness (d) in 3 slice images. (A) Distance r1 (mm) measured on surface of nonperfused region in each SPECT slice after anatomic standardization (voxel size, 2.25 mm). (B) Area determined using distances r1 and r2 extracted to brain surface and trapezoidal formula for trapezoidal approximation.
- FIGURE 2.
3D-SSP (A) and eZIS (B) histograms of SD in normal database obtained at each fc of Butterworth filter. Histogram distribution of SD was generated from SD of each pixel of brain using data from all participants. Each (3D-SSP, eZIS) histogram for SD scores of normal database was obtained at different fc of Butterworth filter. Horizontal axis is SD score; vertical axis is frequency.
- FIGURE 3.
3D-SSP (A) and eZIS (B) histograms of SD in normal database with and without correction. Each histogram of SD scores of normal database was obtained with and without scatter and attenuation correction. Horizontal axis is SD score; vertical axis is frequency. AC+ = with attenuation correction; SC+ = with scatter correction.
- FIGURE 4.
3D-SSP (A) and eZIS (B) z score map images of left lateral brain surface when fc of Butterworth filter of normal database is changed while patient data remain constant. Pixel values are normalized to global brain, and images show decrease in z score. z score images confirm hypoperfused region. z score in each z score map image is scaled to 10.0 from 2.0.
Tables
- TABLE 1
Variation in Average z Scores in Region of Interest at Various Butterworth Filter fc Settings
Processing method fc (cycles/cm) 0.4 0.45 0.5 0.55 0.6 3D-SSP 14.55 14.52 12.82 11.24 10.17 eZIS 14.2 13.91 13.51 12.83 12.24 Processing method fc of Butterworth filter (cycles/cm) 0.4 0.45 0.5 0.55 0.6 3D-SSP 40.21 25.65 7.51 −9.5 −13.33 eZIS 70.86 66.26 55.34 53.09 41.92 Units are % error of measured, compared with true, region size.
- TABLE 3
Evaluation of Error of Hypoperfused Region According to Differences Between Compensation Methods
Processing method NDB−, PD− NDB+, PD+ NDB−, PD+ NDB+, PD− AC SC AC SC AC SC AC SC 3D-SSP 7.81 7.96 −2.15 −3.3 −13.54 19.27 −20.58 −19.79 eZIS 4.53 4.53 −4.12 −4.36 −13.17 10.7 −27.57 −23.87 Data are ratios. NDB− = without correction in normal database; PD− = without correction in patient data; NDB+ = with correction in normal database; PD+ = with correction in patient data.
