Ultrastructural biologic effects of sonography with pulse inversion and microbubble contrast in rabbit liver.
OBJECTIVE
This prospective study was conducted to evaluate the biologic effects of microbubble destruction with pulse-inversion harmonic imaging on rabbit liver parenchyma.


METHODS
The livers of 6 albino rabbits were examined sonographically by a single investigator. Three rabbits underwent contrast-enhanced sonography, with scanning starting 5 seconds after injection by using pulse-inversion harmonic imaging with a mechanical index of 1.2. Four time-triggered images were recorded at a rate of 1 frame every 2 seconds. For comparison, 3 control rabbits had pulse-inversion harmonic imaging with a mechanical index of 1.2 only, without contrast medium. Immediately after sonography, the animals were killed and uninterrupted, thin serial sections of the liver from both groups were analyzed by energy-filtered transmission electron microscopy.


RESULTS
The hepatic parenchyma of rabbits exposed to contrast agents had ultrastructural damage: mitochondria with fragmented crests; interrupted rough endoplasmic reticulum; enlarged intercellular spaces; highly vacuolized cytoplasmic areas; dilated sinusoids, sometimes with an irregular and interrupted endothelial wall; fragmented hepatocyte microvilli in dilated spaces of Disse; fragmented or missing microvilli in bile canaliculi; vacuolated and lysosome-deprived hepatic cytoplasm around the bile canaliculi; markedly injured or fragmented endothelium in larger vessels; and damaged basal membrane. Control-group results indicated that exposure to ultrasound alone did not cause ultrastructural damage to hepatic cells.


CONCLUSIONS
Simultaneous exposure to contrast administration and pulse-inversion harmonic imaging with a high mechanical index causes ultrastructural damage in the rabbit liver.
Caruso
Giuseppe
G
Dipartimento di Biotecnologie Mediche e Medicina Legale, Sezione di Scienze Radiologiche, Università of Palermo, Via del Vespro 127, 90127, Palermo, Italy.
Valentino
Biagio
B
Salvaggio
Giuseppe
G
Lipari
Elvira Farina
EF
Lipari
Diego
D
Brancatelli
Giuseppe
G
Lagalla
Roberto
R
Cardinale
Adelfio Elio
AE
D000818:Animals; D001706:Biopsy; D002466:Cell Nucleolus / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D003287:Contrast Media / Q000009:adverse effects*; D003593:Cytoplasm / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D022781:Hepatocytes / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure*; D008099:Liver / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000528:radiation effects; D008297:Male; D045423:Microbubbles / Q000009:adverse effects*; D046529:Microscopy, Electron, Transmission; D011446:Prospective Studies; D011817:Rabbits; D014463:Ultrasonography
D003287:Contrast Media