Quantifying stenosis in renal arteriograms: A fuzzy syntactic analysis

The introduction of fuzzy logic improves a system for the automatic quantif ication of renal artery lesions seen in digital subtraction angiograms, A t wo-step approach has been followed. An earlier system based on non fuzzy sy ntactic analysis provided a clear symbolic description of the stenotic lesi ons, Although this system worked correctly, it did not take into account th e variability and uncertainty inherent to image processing and to knowledge on the reference diameter. This system has been improved by the introducti on of fuzzy logic in the representation of the reference diameter. It provi des a description of the stenosis in terms of fuzzy quantities, To illustra te the benefits of the fuzzy approach, the results of the two systems have been compared by plotting the differences of an index of variability. It ap pears that the differences are statistically different when using a two-tai led paired t-test (t = 2.37; p = 0.025). The result shows that the fuzzy ap proach is better than a non-fuzzy approach in the sense that the index of v ariability is reduced significantly.