Still no word from the movers. Well, there goes my entire apartment deposit. But, that affords me some more time to type out a blog entry on a cell phone dial pad! T9 makes every sentence seem so much more epic...

Unfortunately, I am unable to post the graphs from the preliminary data analysis, but it appears that the automatic segmentation algorithm lies somewhere between the phase contrast analysis and the manual segmentation. The manual segmentation tends to overestimate when compared to the other techniques, while the PC flow analysis tends to underestimate. Furthermore, the relation between all three is relatively linear, as indicated by a high correlation (0.95 or greater between any two of the three techniques) and a high level of confidence in the zero intercept inear regression.

And perhaps of the greatest importance, the technique demonstrates a "high degree of accuracy," as indicated by Dr. Weinsaft, when used to evaluate the cadiac metrics of subjects with Left Ventricle Disfunction (those who eject only a small portion of their blood in each cardiac cycle, on the order of 25% when compared to normal function of 50 or greater.) This has traditionally been one of the most time consuming

scenarios for a clinician to evaluate, so the time saving benefits from this automatic segmentation stand to be quite considerable.

Admittedly, the data set is still somewhat small (just 20 fully completed cases with an eventual target of 50 to 100). But the trends are already beginning to show. The next step, other than validation with more data sets, is to reconsider the design of the algorithm. As I mentioned before, which technique is more accurate? Phase contrast analysis or manual segmentation? Further, should the algorithm even emulate these techniques or should the design process be independent of other techniques? Perhaps a "true" measure should be experimentally derived using experimentation somehow?

The logistical hurdles of obtaining the truth are considerable. But for now, we are fairly convinced that the automatic segmenter operates consistly between the phase contrast measure and the magnitude measure, both of which are valid and widely used techniques in the clinical world.

## Thursday, July 26, 2007

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