Diagnostic ultrasound ( PDFDrive )

CHAPTER 7 The Pancreas 231
CH PANC
Double duct
sign
C
GB
EH duct
PD
FIG. 7.44 Splenic Vein Clot. Transverse power Doppler image shows
partial splenic vein clot (arrow) caused by chronic pancreatitis. C, Conluence
of splenic and superior mesenteric veins.
acinar atrophy, chronic inlammation, and distorted and blocked
ducts. 91 Chronic pancreatitis ultimately leads to permanent
structural change and deicient endocrine and exocrine function.
Some lasting morphologic changes include alterations in parenchymal
texture, glandular atrophy, glandular enlargement, focal
masses, dilation and beading of the pancreatic duct (oten with
intraductal calciications), and pseudocysts.
Alcoholism is the predominant cause of chronic pancreatitis
(70%-90% in Western countries). 92 Other causes include pancreatic
duct obstruction caused by strictures, hypertriglyceridemia,
hypercalcemia, autoimmune pancreatitis, tropical pancreatitis,
and other genetic mutations. 93
Chronic pancreatitis is characterized clinically by pain,
malabsorption, and diabetes. Treatment of uncomplicated chronic
pancreatitis is usually conservative, with the major aim to improve
the patient’s quality of life by alleviating pain and mitigating
malabsorption and diabetes. Surgical and endoscopic interventions
are reserved for complications such as pseudocysts, abscesses,
and malignancy. 91 Obstruction and thrombosis of the portal veins
may occur (see Fig. 7.37). Chronic pancreatitis may also lead to
obstruction of the pancreatic and bile ducts, sometimes resulting
in the “double-duct” sign (Fig. 7.45). In settings with a high
prevalence of alcoholism, the double-duct sign is caused by
chronic pancreatitis more oten than by periampullary neoplasm. 94
he frequency of common bile duct obstruction in patients
hospitalized for chronic pancreatitis ranges from 3% to 23%
(mean, 6%). he frequency of duodenal obstruction is about
1.2% in hospitalized patients. 95 All of these indings occur in
various combinations and with difering frequency. 8
Approach to Imaging
he imaging diagnosis of chronic pancreatitis depends on detecting
the structural changes associated with advanced disease.
Unfortunately, these changes are rarely present in early disease,
decreasing imaging sensitivity. Consequently, imaging is not very
useful in patients with early chronic pancreatitis. Furthermore,
morphologic changes do not correlate well with endocrine or
exocrine function. 96
FIG. 7.45 “Double-Duct” Sign. Longitudinal oblique image shows
dilation from obstruction of the pancreatic duct (PD) and extrahepatic
bile duct (EH). Chronic pancreatitis often causes the double-duct sign.
GB, Gallbladder.
FIG. 7.46 Dilation of Pancreatic Duct. Transverse sonogram of the
pancreatic body shows a beaded, dilated pancreatic duct, resulting from
chronic pancreatitis.
Despite the common belief that it is diagnostically inferior
overall to CECT, MRCP, and endoscopic ultrasound, 97-99 ultrasound
is oten recommended as the irst diagnostic test. 91 Bolondi
et al. 8 stated that ultrasound diagnosis of chronic pancreatitis
remains diicult because of “the polymorphism of anatomic
changes and the relatively high incidence of false-negative results
in early stages of the disease.”
Ultrasound Findings
Sonography can be efective in diagnosing chronic pancreatitis,
but other tests are generally required if intervention is contemplated.
he hallmark of chronic pancreatitis is ductal dilation
(Fig. 7.46) and calciications, which can be in the branch ducts
(Fig. 7.47), main duct (Fig. 7.48), or both (Video 7.4). When
these indings are present in a patient with pain and a history
of alcoholism, the diagnosis of chronic pancreatitis is secure.