Jaramillo-Núñez A, Zapote-Hernández B, Sánchez-Rinza B, Titla-Tlatelpa JJ

Language: Spanish
References: 7
Page: 345-356
PDF size: 554.02 Kb.

ABSTRACT

Introduction: we are developing a program which has as its primary objective to automatically detect, in bone scintigrams, early bone metastasis and other bone diseases such as osteoporosis, infection, inflammation, etc. Its functioning is based on analysis of shades of gray in the image in regions with high probability of bone metastasis such as the skull, shoulders, vertebrae, ribs, pelvis, etc. Acquisition of shades of gray is based on the pixel elimination method in which, given a threshold value provided by the user, all pixels with values below the threshold are set to zero; in other words “eliminated” and those that remain are analyzed to determine the shades of gray which may indicate a bone abnormality.
Objetive: determine the intervals of shades of gray in the anterior region of the skull from bone scintigrams. The lower and upper limits of the intervals will be entered in the program so that it automatically differentiates healthy and unhealthy cases.
Material and Method: 59 bone scintigrams were chosen at random, from a sample of 138, which were taken from an equal number of patients diagnosed with prostate cancer. Before the study, they were given an intravenous dose of 25 mCi of 99mTc-MDP. Two hours after administration of the radioactive marker they underwent a full body scan with a two-head Mediso Interview XP, version 1.05014 with a LEHR collimator at a rate of 12 cm/min, in anterior and posterior projections. Then the top of the skull was analyzed and the average and standard deviation of the sample were calculated by means of a statistical process. Finally, the values were used to find the intervals.
Results: the intervals of the cases analyzed perfectly differentiate ideal cases from non-ideal cases and infiltrates. This guarantees that the software will perform the process of classifying cases automatically. The quality of the intervals is that they are obtained based on the health of the skull. For an ideal case the interval is from 9 to 43 shades of gray, for non-ideal cases the interval is from 12 to 66, and for infiltrates it is from 32 to 137.
Discussion: the intervals obtained for the sample analyzed perfectly differentiate healthy from unhealthy cases. The preliminary results obtained suggest continuing the analysis, but with a larger sample, although it will not significantly alter the results. When the sample size is increased, it may prove necessary to use another type of statistics different from that used to find the new intervals.
Conclusion: although skulls without metastasis were taken as reference, the method showed bone abnormalities indicating that the majority of the skulls analyzed are not completely “healthy.” The limits of the intervals differentiate healthy from unhealthy cases perfectly well because the shades of gray depend on the “health” status of the skull.

REFERENCES

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