Comparison of standard and second harmonic B-mode sonography in the detection of segmental renal infarction with sonographic contrast in a rabbit model.

Abstract

This study compares contrast-enhanced fundamental and second harmonic B-mode sonography using a rabbit renal infarct model. Segmental renal infarctions were produced in 13 rabbits by embolizing a 0.7 mm bead into the renal artery 1 day prior to imaging. An ultrasonographic unit equipped with an L10-5 transducer and second harmonic imaging capability was used. Real-time recordings were made during the injection of 0.5 ml of an experimental formulation of a perfluorohexane vapor-stabilized microbubble (AF0145) given into the ear vein, and the imaging technique alternated between standard and harmonic imaging every 20 s. Each rabbit received two injections 1 h apart. To control for the effect of peak bolus enhancement, the initial imaging technique used for the first injection was randomized, and the other technique was used initially for the second injection. The videointensity difference between the infarcted and the normal cortex was then calculated and evaluated as a function of time. The infarcted segment could not be seen before administration of contrast agent with either technique. Although the infarction could be seen after injection of contrast agent with either technique, image contrast and contrast duration were nearly 75% greater for the harmonic technique than for the standard technique. AF0145 allows the visualization of segmental renal infarction on standard B-mode imaging. The second harmonic B-mode technique significantly increases image contrast and contrast duration.

Detection of focal renal perfusion defects in rabbits after sulphur hexafluoride-filled microbubble injection at low transmission power ultrasound insonation

“…High transmission power is employed by triggered insonation after injection of air-filled microbubble, producing bubble destruction with the emission of a wideband harmonic signal [9], and it was employed to assess renal parenchyma perfusion, particularly in acute urinary obstruction [18], renal parenchymal diseases, such as acute pyelonephritis [19], acute parenchymal injury [20], acute complications in renal transplant [21,22], and to improve depiction of RPDs in animal models [7,8,11,12]. High transmission power is penalized by the transiency of harmonic signal, the incomplete suppression of background signal, and by the presence of artefacts [7,8,11,12]. Low transmission power is employed by continuous insonation after the injection of perfluorocarbon or sulphur hexafluoride-filled microbubbles [23,24], producing microbubble resonance with emission of harmonic frequencies.…”

“…Contrast-specific modes were introduced to optimize the detection of harmonic signals produced by microbubble insonation and to overcome the limitations of colour/power Doppler US [9], with elimination of blooming and flash artefacts and improvement of both spatial and temporal resolution [10][11][12][13].…”

Gray-Scale Liver Enhancement with Sonazoid (NC100100), a Novel Ultrasound Contrast Agent; Detection of Hepatic Tumors in a Rabbit Model

“…Since the magnitude of the backscattered signal of the contrast agent at the harmonic frequency is greater than that of the tissue, the harmonic mode improves the signal-to-noise ratio and visualizes the distribution of contrast agent microbubbles more effectively. Therefore, the harmonic mode is more advantageous for contrast imaging than the conventional mode, 32,33) and some former generation contrast agents have diagnostic utility only in the harmonic imaging mode because they cannot show contrast effect on tissue perfusion in the conventional mode. 9,34,35) Although Sonazoid was also more efficient in the harmonic mode, it provided significant contrast enhancement in the VX-2 tumor model (Figs.…”

Paediatric ultrasound. I. Abdominal

“…Three-dimensional US offers an improved accuracy of volumetry, particularly in irregularly shaped and hydronephrotic kidneys, and promises to improve sonographic application in chronic renal parenchymal 2361 Fig. 9 a, b Infantile renal cystic disease a in a diffuse syndromal cystic dysplasia, and b the typical ªsalt and pepper imageº of the enlarged kidney in a patient with autosomal-recessive infantile polycystic kidney disease disease such as scarring and reflux nephropathy, possibly in conjunction with echo-enhanced HI [91,92].…”