How is it useful?

• A Z-score is a measure of the distance from the mean of a distribution normalized by the standard deviation of the distribution.
• Mathematically: Z-score = (value-mean)/sd
• Useful for quantifying how different from normal a recorded value is.
• Particularly useful when combining or comparing different features or measures.

How was it used?

• The mean and the standard deviation of the number of cells within Normal Limits and the number of cells similar to Invasive Cancer cells (as defined by DF) per field were calculated for the Normal Biopsies only.
• These values were used to define a within Normal Limits Z-score and a Similar to Cancer Cells Z-score for all 377 biopsies.
• For each biopsy these two Z-scores were combined into a single Morphometric Index which represents how unlike a Normal Biopsy the sample is.

Figure 2: Average Quantitative Scores for 377 Bronchial Biopsies Grouped by Pathology Grade [View Image]

Figure 3: Correlation of Morphometric Index with Pathology Grade [View Image]

Figure 4: Correlation of Architecture Index with Pathology Grade [View Image]