The utility of contrast-enhanced endoscopic ultrasound in monitoring ethanol-induced pancreatic tissue ablation: a pilot study in a porcine model.
OBJECTIVE
Pancreatic ablation is gaining popularity for the treatment of focal pancreatic lesions. The aim of our study was to evaluate local effects of intrapancreatic alcohol injection and the utility of contrast-enhanced endoscopic ultrasound (EUS) for its monitoring in a porcine model.


METHODS
We performed four survival experiments on 50-kg pigs. Under linear EUS guidance, 0.5 mL of 50% ethanol plus purified carbon particle solution (GI Spot) was injected into the pancreatic body to create a focal area of pancreatic necrosis. The animals survived for 24-48 hours (pigs # 1, # 2, and # 3) and 7 days (pig # 4). EUS was then repeated with and without perflutren lipid microspheres (Definity) administration through the peripheral vein. Standard and microsphere-enhanced images of the pancreas were compared. Afterwards the animals were euthanized for necropsy.


RESULTS
Alcohol injection caused focal pancreatic necrosis, which was barely seen by standard EUS as a subtle hypoechoic lesion 1 cm in diameter. Color and power Doppler EUS of this region did not reveal any blood flow. After intravenous injection of microspheres, color Doppler EUS revealed marked contrast enhancement of normal pancreatic parenchyma with a clearly delineated avascular alcohol-treated area, which on postmortem examination corresponded to the discrete necrotic area marked with carbon particles.


CONCLUSIONS
EUS-guided alcohol injection consistently causes focal areas of pancreatic necrosis. Contrast-enhanced EUS with microspheres improves visualization of altered pancreatic vascular perfusion and can be used to facilitate detection of small pancreatic lesions and its follow-up post-ablation.
Giday
S A
SA
Department of Medicine, Division of Gastroenterology, Johns Hopkins Hospital, Baltimore, Maryland 21205, USA.
Magno
P
P
Gabrielson
K L
KL
Buscaglia
J M
JM
Canto
M I
MI
Ko
C W
CW
Clarke
J O
JO
Kalloo
A N
AN
Jagannath
S B
SB
Shin
E J
EJ
Kantsevoy
S V
SV
D000818:Animals; D002424:Caustics / Q000008:administration & dosage*; D003287:Contrast Media / Q000008:administration & dosage*; D004195:Disease Models, Animal; D019160:Endosonography; D000431:Ethanol / Q000008:administration & dosage*; D007089:Image Enhancement; D015552:Injections, Intralesional; D007275:Injections, Intravenous; D008863:Microspheres; D009336:Necrosis; D010179:Pancreas / Q000000981:diagnostic imaging* / Q000473:pathology; D010865:Pilot Projects; D013552:Swine
D002424:Caustics; D003287:Contrast Media; D000431:Ethanol