Research ArticleCLINICAL INVESTIGATIONS

Results of Preliminary Clinical Trials of the Positron Emission Mammography System PEM-I: A Dedicated Breast Imaging System Producing Glucose Metabolic Images Using FDG

Kavita Murthy, Marianne Aznar, Christopher J. Thompson, Antoine Loutfi, Robert Lisbona and Jean H. Gagnon
Journal of Nuclear Medicine November 2000, 41 (11) 1851-1858;

Article Figures & Data

Figures

  • FIGURE 1.
    FIGURE 1.

    Photograph of PEM-1 system installed in mammography unit at Cedars' Breast Clinic. Lower detector is housed in standard mammographic magnification table and positioned below breast. Upper detector is positioned above compression paddle.

  • FIGURE 2.
    FIGURE 2.

    Schematics showing position of PEM detectors during acquisition of mammogram (A) of breast and emission scan (B) of breast. During mammogram, coregistration tool occupies position of PEM detectors. During emission scan, detectors replace coregistration tool.

  • FIGURE 3.
    FIGURE 3.

    Basic principles of data acquisition and limited-angle backprojection used in formation of PEM images. Planar PEM images are displayed in sets of 7 frames, with leftmost frame corresponding to slice closest to upper detector.

  • FIGURE 4.
    FIGURE 4.

    Formation of 7 planar images. Volume of breast between detectors is divided into 7 equal slices. Point of interaction of LOR with 7 planes is used to localize event in that plane. Final image set consists of 7 frames, each of which corresponds to 1 slice.

  • FIGURE 5.
    FIGURE 5.

    Typical set of true-positive PEM-I images, with upper row showing 7 emission images from breast with suggestive findings and lower row showing images from contralateral breast. Each image frame represents 1 slice through breast, with upper edge of frame corresponding to region of breast closest to chest wall and leftmost frame corresponding to image plane closest to upper detector. Localized region of preferential FDG uptake is visible in upper set of images. Pathologic evaluation of excised mass revealed infiltrating and intraductal carcinoma (2.5 × 2.2 × 2.2 cm, histologic grade 3 [Bloom Richardson], nuclear grade III).

  • FIGURE 6.
    FIGURE 6.

    True-positive PEM image in pseudocolor overlaid on its corresponding mammogram in gray scale. Outline of coregistration tool, which appears white on mammogram (shown in green here), is used to scale best-focused PEM image. That image is then overlaid on mammogram. Top of image corresponds to region closest to chest wall of subject; left side of image corresponds to left side of imaged breast.

Tables

  • TABLE 1.

    Comparison of PEM and Mammography Results

    IndexMethod of calculationImaging modality (%)
    PEMMammography
    SensitivityTP/(TP + FN)8090
    SpecificityTN/(FP + TN)10050
    AccuracyTP + TN/(TP +  TN + FP + FN)8678
    Positive predictive valueTP/(TP + FP)10081
    Negative predictive valueTN/(TN + FN)6767

    • TP = true-positive; FP = false-positive; FN = false-negative; TN = true-negative.

  • TABLE 2.

    Summary of Results

    Subject no.MammographyPEMCount rate difference* (%)PathologyHistology
    GradeSize (cm)
    1+−6−NA3.2 × 2.6 × 2.2
    2−+ (CA)43+31.1 × 1.1 × 0.9
    3++ (HS + CA)21+21.5 × 1.0 × 1.0
    4++ (HS + CA)17+32.5 × 2.2 × 2.2
    5++ (CA)22+25.5 × 4.5 × 2.8
    6++ (HS)0+31.8 × 1.5 × 2.5
    7+−−4−NA2.5 × 1.9 × 1.0
    8++ (HS + CA)51+23.0 × 3.0 × 2.0
    9−−2−NA1.5 × 1 × 1.2
    10++ (HS + CA)9+31.5 × 1.5 × 1.3
    11+−−13+21.5 × 1.3 × 1.0
    12−−−21−NA5.5 × 3.5 × 2.5
    13+−8+15.2 × 1.5 × 1.3
    14++ (CA)53+21.2 × 1.0 × 1.2

    • ↵* Difference between counts in breast with suggestive findings and counts in contralateral breast.

    • CA = count-rate asymmetry (>10% difference in count rates in breast with suggestive findings and contralateral breast); HS = tumor visible as hot spot in image.

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