摘要:

AbstractCoronary stenosis results in transmurally non‐uniform blood flow with the inner layers of the left ventricular wall typically suffering a more severe hypoperfusion relative to the outer layers. Coupled with numerous other transmural non‐uniformities such as systolic tension development and oxygen needs, the heterogeneous blood flow distribution in the presence of coronary stenosis is expected to result in transmurally heterogeneous ischemia. All previous NMR spectroscopy studies of myocardial metabolism and bioenergetics under normal and ischemic conditions treated the organ as a homogeneous tissue. We have utilized spatially localized31P NMR spectroscopy together with non‐NMR measurements of regional blood flow to study the myocardium with transmural spatial differentiation under normal and flow‐restricted conditions.31P NMR and blood flow data obtained concurrently on each heart revealed that sustained coronary artery stenosis resulted in transmurally non‐uniform ischemia which largely paralleled the hypoperfusion pattern. The reduction in creatine phosphate content (with consequent elevation of Pi) and hypoperfusion was tightly correlated in the subendocardium for flow rates less than ∼0.7 mL/min per g wet myocardium. The high energy phosphate and Picontent of the epicardium, however, was responsive not only to the flow to this region but also to the extent of ischemia in the subendocardial layers. These results document the utility of localized NMR spectroscopy in physiologic research and suggest potential biomedical applications due to the tight correlation noted between alterations in blood flow and changes in the phosphorylated metabolite levels detecte

ISSN:0952-3480    

DOI:10.1002/nbm.1940020523

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractArtifacts due to localized susceptibility effects, variations in the spin‐lattice relaxation time constants of signals and a mixing of signals arising from tissue motions can contaminate otherwise credible results. The sources and magnitude of some of these are discussed and their likely impact assessed, so that the necessity of incorporating additional measurements in an individual study can be demonstrate

ISSN:0952-3480    

DOI:10.1002/nbm.1940020524

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractLocalization techniques are considered an indispensable part of the clinical spectroscopy examination. The results are often a marked improvement in diagnostic information (amplification), but because of the introduction of new artifacts and the more prolonged examination time, some of the undoubted advantage is lost (obfuscation). There is thus an argument for continued development of more rapid methods of clinical spectroscopy and, if necessary, sacrificing some spatial information.

ISSN:0952-3480    

DOI:10.1002/nbm.1940020525

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

ISSN:0952-3480    

DOI:10.1002/nbm.1940020502

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY