Intraductal ultrasonography (IDUS) is a reliable procedure for evaluating the biliopancreatic
duct during endoscopic retrograde cholangiopancreatography (ERCP) [1]
[2]; however, conventional high frequency IDUS is limited by its penetration depth [3]. This case highlights a novel dual-frequency IDUS probe that overcomes this limitation
([Fig. 1]; [Video 1]).
Fig. 1 Photograph of the dual-frequency intraductal ultrasonography probe showing: a the probe, which features two frequencies (20 MHz and 7.5 MHz) that are switchable
via the main engine; b the probe tip, which has an outer diameter of 2.5 mm.
A novel dual-frequency intraductal ultrasonography probe is used to evaluate biliopancreatic
disease during endoscopic retrograde cholangiopancreatography.Video 1
A 60-year-old woman was referred to our hospital with jaundice. Magnetic resonance
imaging
(MRI) revealed a pancreatic head mass with distal bile duct obstruction ([Fig. 2]). Laboratory tests showed she had a serum total bilirubin of 330 μmol/L and a CA19-9
of
146 U/mL, and a preliminary clinical diagnosis of pancreatic head cancer was made.
Fig. 2 Enhanced magnetic resonance imaging and magnetic resonance cholangiopancreatography
(MRCP) images showing: a in arterial phase, mild enhancement of the pancreatic head lesion; b in portal phase, progressive enhancement; c on MRCP, a distal bile duct stricture with upstream bile duct dilatation and slight
pancreatic duct dilatation.
Endoscopic retrograde cholangiography (ERC) revealed a defect in the distal bile duct
on contrast injection. To determine the nature of this biliary stricture, a novel
IDUS probe with dual frequencies of 20 MHz and 7.5 MHz (DP-27, 7.5+20 MHz; Innermed,
Shenzhen, China) was advanced over guidewires into the pancreatic duct and bile duct,
which were scanned using the pull-back method. Using the 20-MHz frequency, the IDUS
scan showed the pancreatic duct and proximal surrounding structures ([Fig. 3]
a). On switching to 7.5 MHz, the far-field resolution significantly improved, allowing
visualization of the complete pancreatic contour and parenchyma ([Fig. 3]
b). The pancreatic head appeared as a heterogeneous hypoechoic region without any evident
tumorous lesions. A subsequent 20-MHz scan of the intrapancreatic bile duct revealed
a circular symmetrical wall thickening, with a smooth outer margin ([Fig. 3]
c). A switch to 7.5 MHz confirmed no evidence of an extrinsic lesion causing compression
([Fig. 3]
d).
Fig. 3 Images during dual-frequency intraductal ultrasonography (IDUS) showing; a the appearance on 20-MHz IDUS of the pancreatic duct; b on 7.5-MHz IDUS, a high resolution image of the pancreatic parenchyma; c on 20-MHz IDUS, intrapancreatic biliary wall thickening; d on 7.5-MHz IDUS, detailed periductal structural information.
The IDUS images were therefore used to make a diagnosis of autoimmune pancreatitis
and IgG4-related sclerosing cholangitis (IgG4-SC), which was confirmed by finding
an elevated serum IgG4 level and on endoscopic ultrasound-guided fine-needle aspiration
(EUS-FNA). Following glucocorticoid therapy, the patient’s symptoms resolved, and
imaging showed significant improvement. This dual-frequency IDUS technology offers
enhanced diagnostic capability and can be seamlessly integrated into routine ERCP
procedures, significantly reducing diagnostic delays and improving patient management.
Endoscopy_UCTN_Code_TTT_1AS_2AD
E-Videos is an open access online section of the journal Endoscopy, reporting on interesting cases and new techniques in gastroenterological endoscopy.
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