The Perfusion–Diffusion Mismatch: How and When?
The MTT is ideally inversely proportional to the regional perfusion pressure and, hence, closely related to the regional risk of ischemic injury in areas of normal DWI (mismatch). The mismatch volume depends on how MTT is determined and its significance seems to depend on the time of its measurement. Methodologically, “true” MTT is defined as area divided by height of the impulse response (tissue concentration curve if contrast was delivered as an infinitely narrow pulse), found by deconvolving the tissue concentration time curve with an arterial input.53 In acute stroke, the contralateral MCA is generally chosen to represent the arterial delivery of tracer to all brain tissue. Deconvolution techniques are, however, sensitive to dispersion and, in some cases, delays of the arterial input downstream of where it is measured. In cases in which blood reaches tissue through collaterals, the chosen arterial input is not truly representative and causes underestimation of MTT, and bias mismatc
Related Questions
- On real devices, the link lights would still come up if there is a duplex mismatch between both sides of the Ethernet connection. Why does Packet Tracer not model this behavior?
- I am attempting to create a relationship between two tables in Access, but keep getting a type mismatch error, every time I attempt to run the query. What is the problem?
- When starting the PAC, the error message RPC Program Mismatch appears. What does this mean?
