Evaluation of flash echo imaging of the canine gastrointestinal tract.

Abstract

Although it is important to assess gastrointestinal blood flow, no generally useful, noninvasive assessment method has been established. Harmonic flash echo imaging, which is an intermittent second harmonic imaging technique, has recently become available to evaluate blood flow. We investigated the usefulness of harmonic flash echo imaging in the assessment of the gastrointestinal tract, and we used this technique to study the effect of nicotine on small bowel blood flow. Harmonic flash echo imaging was performed at the beginning of intravenous injection of a contrast agent. It was also performed on the small bowel immediately before and 10 min after nicotine administration to evaluate blood flow. Gastric and small bowel walls were clearly enhanced on the primary images. Small bowel enhancement, which is regarded as transmural blood flow, significantly decreased after nicotine administration. Harmonic flash echo imaging appears to be useful in the assessment of the transmural blood flow in the gastrointestinal wall.

Contrast-enhanced ultrasonography with Sonazoid™ for the evaluation of bowel ischemia

“…Hamada et al also reported a sensitivity of 94.1% and a specificity of 100% using advanced dynamic flow for the diagnosis of bowel ischemia. However, the continuous visualization of transmural blood flow was difficult because microbubbles of Levovist TM are easily destroyed and often burst before the agent has the opportunity to enter the target organ [29]. On the other hand, Sonazoid TM consists of microspheres of perfluorobutane stabilized by a monomolecular membrane of hydrogenated egg phosphatidyl serine embedded in an amorphous sucrose structure; this formulation overcomes the stability problems associated with other ultrasound contrast agents and enables a clearer real-time visualization of the ischemic bowel wall than Levovist TM .…”

“…Real-time images allow the study of the dynamic behavior of internal anatomy and pathology (e.g., peristalsis of bowel). Although conventional color/power Doppler imaging has been widely used for the diagnosis of bowel ischemia [3], this modality cannot visualize capillary blood flow in tissues because of sensitivity limitations as well as the interference produced by various artifacts [29].…”

“…Transabdominal ultrasonography is a noninvasive method used for the morphologic diagnosis and evaluation of blood flow during the assessment of bowel diseases [29]. Ultrasonography is relatively inexpensive and a suitable modality for repeat examinations.…”

Predicting the need for surgery in Crohn's disease with contrast harmonic ultrasound

“…However, no report has evaluated the relationship between the clinical course and blood flow within the affected bowel among patients with active CD. To examine bowel blood flow in CD in detail, we used H-FEI to circumvent the limitations of Doppler imaging [9,10].…”

“…When we subtracted secondary ( Figure 4B) from primary images ( Figure 4A), image alignment was not necessary, since the very short interval between images precluded more than negligible motion effects ( Figure 4C). The gray scale was corrected for linearity with the gray-scale bar on the image, and the mean pixel value (dB) was calibrated from the mean pixel intensity using the NIH Image program [9,20]. Because the signals backscattered from tissue underwent logarithmic amplification to obtain a broad-banded gray-scale image, we calculated the antilog of the mean pixel value (dB) (10 [mean pixel value (dB)/20] ) to construct a timeintensity curve (TIC), and used the resultant value to represent gray-scale amplitude to calculate the area under the curve (AUC) as an indicator of microcirculation ( Figure 4D).…”