Blood flow in the splanchnic veins was studied in cirrhotics and matched controls by means of a system that combines a mechanical sector scanner with a pulsed Doppler. The measurements were validated in an in vitro model. Echo-doppler studies could be carried out reproducibly in only approximately two-thirds of cases because of poor echo transmission or incomplete cooperation. Portal blood velocity was significantly reduced in cirrhotics (10.5 +/- 0.6 cm/s versus 16.0 +/- 0.5 in controls; p less than 0.001), but portal blood flow was normal because of enlarged portal caliber. A complete hemodynamic evaluation of the splenic and superior mesenteric veins was possible in only a few subjects. In selected patients the technique may prove relevant in the study of hemodynamic effects of drugs and surgery on portal blood flow.
The M-mode (motion mode) technique has improved the diagnostic possibilities of echocardiography due to its high temporal resolution. The use of a two-dimensional (2D) image as a basis for M-mode analysis at a defined line, independent of the transducer orientation, namely the anatomic M-mode (AMM), has been proposed from the beginning of 2D echocardiography. For several years, however, this could not be accomplished due to several reasons including the limited digital memory, the relatively rough pixels of 2D images, and the low temporal resolution of the screen. The AMM has been improved by the "fully digital" machines. These are able to provide a series of digital data (direction, position, and timing) relative to any single echo received from any point of the tissue. AMM analysis, thus, can be performed in any direction, as a "normal" monodimensional echocardiogram. With respect to traditional M-mode, AMM permits a more detailed analysis of cardiac chambers diameters obtained by linear measurements, regional wall motion of the left ventricle (both at rest and during stress), and location of accessory pathways. In particular, the assessment of left ventricular regional wall motion represents the most important goal of this new technique, which results in marked reduction or even elimination of the limitations due to the subjective character of wall motion evaluation with 2D echocardiography.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.