Journal of neuroimaging : official journal of the American Society of Neuroimaging
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The authors investigated the feasibility and accuracy of intravascular Doppler sonography (IVDS) with a newly developed microprobe. ⋯ For percutaneously directly reachable vessels, the transcutaneous Doppler sonography is the choice for easy noninvasive and inexpensive measurement of blood flow velocity. However, for vessels that are difficult or impossible to reach percutaneously, intravascular measurement is a valid procedure.
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Case Reports
Does reversal of ischemia on diffusion-weighted imaging reflect higher apparent diffusion coefficient values?
This study investigated whether ischemia on diffusion-weighted imaging (DWI) that reverses has higher apparent diffusion coefficients (ADCs). A patient treated with thrombolytics was evaluated with serial magnetic resonance imaging studies before treatment, at 3 and 14 days and at 4 weeks. ⋯ The mean ADC was 7.43 x 10(-3) mm2/s in the 6 regions that reversed and 7.31 x 10(-3) mm2/s in the 6 regions that persisted (P < .036). With thrombolytic treatment, large ischemic lesions on DWI may reverse, and these areas display higher mean ADCs.
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Ultrasound contrast agents (UCAs) have a distinct diagnostic impact on transcranial Doppler (TCD) and duplex sonography. In addition to the properties of the UCA and ultrasound imaging modes, the duration of contrast enhancement depends on the administration mode. Infusion of UCAs may be appropriate for prolonging the diagnostically useful time of elevated Doppler intensity. ⋯ Pharmacokinetic analysis of SonoVue during inflow (by exponential functional fitting of the time-mean intensity curves) and elimination (by linear regression analysis) revealed no dose-related differences. This study demonstrated a dose-dependent level of increased Doppler mean intensity within the brain circulation during infusion of SonoVue. Unlike the bell-shaped course of Doppler signal enhancement seen after bolus injection, infusion generates a stable plateau, which is an important prerequisite for more advanced contrast applications.