Biomedical subjects

Marielle Scherrer-Crosbie

Publications and source records attributed to Marielle Scherrer-Crosbie.

3 recordsLinked to original sources

PubMed2002

Pulse inversion harmonic imaging improves endocardial border visualization in two-dimensional images: comparison with harmonic imaging.

Pulse inversion harmonic imaging (PIHI) is a new modality that increases the detection of harmonic echoes and myocardial contrast by cancelling linearly transmitted signals. We tested whether PIHI improved the detection of endocardial borders in noncontrast 2-dimensional echocardiography. We compared PIHI with tissue harmonic imaging (THI), which decreases linearly transmitted signals using filters. Fundamental mode (FM) was compared with THI and PIHI in 50 consecutive patients. The global and segmental endocardial visualization scores measured with FM were significantly improved by using either THI or PIHI. The improvement of the global score compared with FM was slightly higher using PIHI than THI, because of an improved visualization of the base and the anterior wall with the PIHI technique compared with THI. The ratio of myocardial-to-cavity signal was similarly increased from FM with THI and PIHI. PIHI, a new modality for detection of myocardial contrast, can also be used for endocardial border visualization. It provides an improvement relative to THI for specific regions of the endocardium.

Echocardiography↗

PubMed2002

Echocardiography improves detection of rejection after heterotopic mouse cardiac transplantation.

BACKGROUND: Current assessments of cardiac rejection in murine transplant models rely on subjective estimates of the force of the palpable heart beat that have limited sensitivity and precision. METHODS: We used 2-dimensional echocardiography to evaluate changes in left ventricular posterior wall thickness (PWT) in a heterotopic cardiac mouse transplant model of rejection. Nine allografts and 6 isografts were imaged daily for 6 days and harvested. Thirteen allografts were imaged daily and harvested at day 3. RESULTS: Intraobserver variability on PWT was 0.003 +/- 0.09 mm, interobserver variability 0.09 +/- 0.11 mm. Allograft PWT increased after transplantation (0.74 +/- 0.02 mm to 1.28 +/- 0.05 mm at day 5, P <.0001). For isografts, PWT remained constant (0.73 +/- 0.03 mm to 0.85 +/- 0.01 mm) after an initial increase at day 1. Palpation failed to identify rejection at day 3 whereas PWT was already increased (1.15 +/- 0.02 mm in the allografts at day 3 vs 0.85 +/- 0.02 mm in the isografts, P <.0001). There was a relation between histologic score and PWT (P <.0001). CONCLUSION: Two-dimensional echocardiography allows the noninvasive detection and follow-up of cardiac rejection after transplantation. It eliminates the subjectivity of palpation and provides quantitative and reliable indices of rejection.

Animals↗

PubMed2002

Effect of destructive pulse duration on the detection of myocardial perfusion in myocardial contrast echocardiography: In vitro and in vivo observations.

UNLABELLED: Myocardial perfusion is detected with contrast echocardiography by comparing a contrast-enhanced image with a baseline obtained before contrast injection (true baseline) or after myocardial bubble destruction after a high-power destructive pulse (postdestructive pulse baseline). Although it is assumed that all bubbles are destroyed by a destructive pulse insuring optimal contrast detection, this assumption has not been tested. In 18 participants we compared the videointensity (VI) differences among the contrast-enhanced image, the postdestructive pulse baseline, and the true baseline using both triggered high-mechanical index imaging and real-time imaging. VI difference was significantly greater for the true baseline with both techniques at all ventricular levels. The benefit of using a true baseline was less when the duration of the destructive pulse was increased. Similarly, we quantified VI in a flow phantom using continuous Optison (commercially available perfluoropropane-filled albumin microbubbles) (Amersham, Princeton, NJ) infusion and variable durations of destructive pulses. VI decreased with the duration of the destructive pulse and reached a plateau after a duration of 8 to 15 frames. The plateau reached after a long destructive pulse was dependent on flow rate and concentration and never reached a true baseline, unless concentration (<100 microL/L) and flow rate (<0.5 cm/s) were very low. IN CONCLUSION: (1) in clinical studies, the difference in VI between contrast-enhanced and baseline images is greater when true baseline is used; (2) the longer the destructive pulse, the closer the postdestructive pulse baseline to true baseline; and (3) this effect exists in all regions of the left ventricle.

Adult↗