Last week I put more effort on one of Dr. Prince's new project: comparing the change of portal vein flow before and after meal in normal people and cirrhotic patients. Dr. Prince, me and other two medical students are working on the the pre-experiment part right now. Tons of problems with new ideas poped out, which made this week compact and intense.
It has been a long time that doctors found food intake can cause significant increase of portal blood flow, however, fibrous scar and regenerative nodules generated in cirrhosis can severely affect the liver reserve of this flow change. Studies on the comparison of this flow change between normal volunteers and cirrhotic patients by Doppler measurements started about decades ago. But because of the poor accuracy of Doppler in flow measurements, all the previous studies have many discrepancies, rendering this mecomparison not feasible in the diagnosis for early cirrhosis.
On the other hand, MRI can also do the flow measurement using PC (phase contrast) sequence. So Dr. Prince came up with the idea that whether MR can be used to improve the measurement of the portal flow change. Last week, we first tried out this measurement on him before and after meal. Surprisingly, after several repeated scanning, we found the measurement of the same portal flow can be very different in PC. What may cause the measurement error in PC? If we found them out, is it possible that we can get much better measurement of portal flow using MR?
Aiming for discorvering a better non-invasive diagnosis for early cirrhosis, we thought about many parameters that can be modified to achieve the improvement: resolution, SNR, and tricks to make the contour of portal vein, etc. To test these ideas, we need a proper phantom of human portal vein first. Then we came up with the "U-shape tubing phantom" idea. We connected a tubing bended into U shape to the injector of contrast agent and this could work as a nice continous flow phantom mimicing portal vein within 1 minute. Comparing the flow measurement obtained from both "in" and "out" profile of this tubing, we could get an idea about how sensible the scanning method or how accurate the measurement is with the known flow rate in the phantom.
After a whole week fighting with air bubbles, water leakage and all kinds of problems, we have finally got some very useful preliminary data. I am excited about this and will continue to do more measurement this week after analysing the current data thoroughly. I will keep you guys posted on this~
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