Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Biotech / Medical : Caprius(CAPR), Breast MRI(former ANMR/MAMO) -- Ignore unavailable to you. Want to Upgrade?

To: Zeev Hed who wrote (2118)	11/11/1997 8:29:00 AM
From: James L. Fleckenstein	Read Replies (3) \| Respond to of 2615

I might be able to help. First, let me dispense with my friend Luis' issues: <<Homogeneity depends on the tissues water and fat as much as it may depend on the magnetic fields..Resolution is in the mm something like 1~3mm... size of the tiniest tumors other than the micro tumors that form in the tiny channel like breast things.. but those are surrounded by softer tissue that absorbs galodinium... Dc Fleckenstein this is more your bag please explain...>> There is homogeneity of the tissue (water and fat) and of the magentic field. The former is what the patient brings in with them, the latter is something we can control. The resolution of the fat and water frequencies is critically dependent upon both the field strength and the homogeneity of the magnet. Without these, one cannot resolve the frequencies, and if you can't do that you have no hope of getting selective fat- and water- images. The tiny tumors that we hope to see with gad are indeed on the order of mm. When it comes to these tiny tissues, the poroblems with subtraction that Zeev correctly identifies become substantial, with the exception of temperature which will not fluctuate enough between the pre- and post- gad images to matter. As for the "hanging" and other misregistration artifacts, the are a big deal in substraction techniques. If one is stuck with this technique, then one tries to minimize the subtraction problems. Thes include fixing the breast in an immobile position, not a "hanging" position. Also, if you arrange your sequence such that it is obtained in a sort of a CINE sequence so that the first image is obtained before injection and a series of partial K-space images (quicker on order of 1-2 sec) are obtained over several minutes during a rapid infusion of gad (over 5 seconds say). A curve is generated that monitors the rate of enhancement and both benign and malignant tumors enhance but at different rates. It is on the basis of the rate of enhancement that the MRI diagnosis is made.