Pancreas Ultrasound: Anatomy, Imaging, and Pathology (Chapters 1–8)

A vocabulary-style set of flashcards covering pancreatic anatomy, imaging landmarks, ducts, normal measurements, pathology (pancreatitis, cystic lesions, tumors), endocrine/exocrine functions, MEN1, and surgical management (Whipple).

Pancreas location

A gland located mainly in the epigastric region with the tail extending toward the left hypochondriac region; head lies posteriorly and the pancreas sits in the lap of the duodenum.

Uncinate process

A hook-like part of the head of the pancreas that extends posteriorly toward the spine.

Pancreatic head, neck, body, tail

Anatomical divisions of the pancreas: head (most inferior, near the duodenum), neck (anterior to the portal confluence), body (largest part), tail (superior, near the spleen).

Portal confluence

The junction where the splenic vein and superior mesenteric vein meet to form the portal vein.

Superior mesenteric artery (SMA)

Major artery that runs anterior to the pancreas; serves as an anatomic landmark on ultrasound.

Aorta and left renal vein relation

The left renal vein courses anterior to the aorta and posterior to the SMA, located near the pancreas in cross-section.

Gastroduodenal artery (GDA)

Artery near the pancreatic head; a key landmark in identifying the head region on ultrasound.

Common bile duct (CBD)

Duct that drains bile from the liver and gallbladder; runs near the pancreatic head and joins the pancreatic duct before entering the duodenum.

Duct of Wirsung

Main pancreatic duct that runs the length of the pancreas and drains into the duodenum via the ampulla of Vater.

Duct of Santorini

Accessory pancreatic duct that drains part of the pancreas and also joins the CBD toward the duodenum.

Ampulla of Vater

Site where the pancreatic duct and common bile duct join and empty into the duodenum.

Duodenum four parts

C-shaped segment of small intestine surrounding the head of the pancreas; parts 1-4 describe its course and relation to the pancreas.

Transverse vs longitudinal views (US)

Transverse view cuts the body crosswise; longitudinal view runs along the length of the organ to show its contours and relationships.

Coin purse view

A nickname for the pancreatic neck–uncinate view seen in some ultrasound angles where the SMV appears between neck and uncinate process.

Normal pancreas size (AP measurement)

Typically about 3 cm in the anteroposterior (AP) dimension; measurement method affects normals.

Pancreatic echotexture

Usually homogeneous on ultrasound; coarse or heterogeneous texture suggests pathology (e.g., pancreatitis, mass, calcifications).

Normal CBD diameter

Typically less than 3 mm in the head of the pancreas (some sources vary between 2–3 mm).

Pancreatic duct size (Wirsung)

Pancreatic duct should be small; dilation may indicate obstruction; normal values are usually under a few millimeters (often cited as <2–3 mm).

Islets of Langerhans

Endocrine cell clusters (beta cells primarily) in the pancreas that secrete hormones into the bloodstream (insulin, glucagon, somatostatin).

Endocrine vs Exocrine pancreas

Endocrine: hormone-secreting islets into blood (ductless). Exocrine: acini cells secrete digestive enzymes through ducts into the duodenum.

Insulin

Hormone produced by beta cells of the islets; lowers blood glucose by promoting cellular glucose uptake.

Glucagon

Hormone produced by alpha cells; raises blood glucose by promoting glucose release from liver.

Somatostatin

Hormone that inhibits release of several other hormones; produced by delta cells in the pancreas.

Pancreatic enzymes (exocrine)

Lipase, amylase, trypsin (proteases) and others; released as pancreatic juice into the duodenum to aid digestion.

Ductal anatomy (Wirsung vs Santorini)

Wir s ung = main pancreatic duct; Santorini = accessory duct that can drain part of the pancreas and join the CBD.

Annular pancreas

Congenital condition where pancreatic tissue encircles the duodenum, potentially causing obstruction.

Divisum pancreas

Anatomic variant where pancreatic ducts do not fuse, resulting in separate drainage routes.

Whipple procedure (pancreaticoduodenectomy)

Surgical resection of the pancreatic head and duodenum with reconstructions: pancreaticojejunostomy, choledochojejunostomy, and gastrojejunostomy (or pylorus-preserving variant).

Whipple indications

Often indicated for pancreatic head/uncinate tumors or certain pancreatitis etiologies near the head.

Liver, gallbladder, and biliary relationships

Liver is a major source of bile; common bile duct travels with the pancreatic duct to the duodenum; gallbladder stores bile and may be removed during Whipple.

Obstructive jaundice due to pancreatic head mass

Masses in the head can obstruct bile flow, causing jaundice and a palpable, non-tender gallbladder (Courvoisier sign).

Pancreatitis (acute vs chronic)

Acute pancreatitis is a new inflammatory episode; chronic pancreatitis involves recurrent inflammation with scarring and calcifications.

Pseudocyst

Fluid collection associated with pancreatitis; may form a pseudo-capsule as a complication of chronic or severe acute pancreatitis.

Pancreatic calcifications

Calcifications within the pancreas commonly seen in chronic pancreatitis; appear as bright echoes on US.

Phlegmonous pancreatitis

Inflammatory pancreatic tissue with surrounding inflammatory changes; may obscure normal pancreatic borders.

Abscess and peritonitis

Pancreatic abscess is infected fluid collection; peritonitis is peritoneal infection, often secondary to pancreatitis.

Cystic pancreatic lesions

Cysts in the pancreas include serous cystadenoma (microcystic, benign), mucinous cystadenoma (macro), and IPMN.

Serous cystadenoma

Microcystic benign pancreatic cyst; may show many tiny cysts.

Mucinous cystadenoma

Macrocystic malignant potential cystic pancreatic tumor; larger cysts with mucinous content.

Intraductal papillary mucinous neoplasm (IPMN)

Mucin-producing tumor arising in or near the pancreatic ducts; potential for benign or malignant behavior.

Adenocarcinoma of the pancreas

Most common pancreatic cancer; exocrine tumor with poor prognosis, often presents earlier if in head (causing jaundice) than tail.

Lymph nodes and pancreatic cancer

Enlarged retroperitoneal/para-aortic lymph nodes are common in pancreatic cancer and indicate spread risk.

Courvoisier sign

Non-tender enlarged gallbladder with obstructive jaundice, suggestive of pancreatic head mass.

MEN1 (multiple endocrine neoplasia type 1)

Endocrine syndrome affecting pituitary, adrenal (parathyroid), and pancreas; may include pancreatic neuroendocrine tumors like insulinoma.

Insulinoma

Islet cell tumor producing excess insulin; causes hypoglycemia symptoms.

Gastrinoma

Islet cell tumor producing excess gastrin; causes peptic ulcers and GI upset.

Glucagonoma, VIPoma, Somatostatinoma

Rare functioning islet cell tumors producing glucagon, vasoactive intestinal peptide, or somatostatin respectively.

Islet cell tumors (neuroendocrine)

Tumors arising from pancreatic islets with potential hormone production; can be functioning or nonfunctioning.

Pancreatic ducts in pathology

Ductal dilation, calculi, or obstruction commonly seen with pancreatic diseases and tumors.

Normal relationships on US landmarks

SMA and aorta are key landmarks; SMA lies anterior to uncinate process; splenic artery along superior border; SMV often posterior to neck/uncinate; portal confluence just medial to neck.

Stomach window technique

Having the patient drink water and roll to the right side to create a fluid window that helps visualize the pancreas by displacing gas-filled stomach/duodenum.

Ultrasound preparation

NPO status; sometimes give water for window; position supine or oblique; use color Doppler to differentiate vessels from ducts.

Longitudinal pancreas view challenges

Not routinely imaged in long; is used mainly to assess pathology; relies on landmarks like left lobe of liver and left kidney.

Trabeculated pancreatic tail

Tail near left kidney; more posterior and superior; may be difficult to visualize on US.

Regional anatomy for scanning

Abdominal regions: pancreas primarily in epigastric; tail extends to left hypochondriac; relationships to stomach, duodenum, liver, spleen, kidney.

Pancreatic cancer prognosis by location

Cancer in the head often detected earlier due to ductal dilation and jaundice; tail/body cancers have poorer early symptoms and worse prognosis.

Laparoscopic/robotic Whipple

Minimally invasive variants of the Whipple procedure; open approach is traditional and time-tested.

Ductal dilation signs on US

Dilated pancreatic or common bile ducts on ultrasound can indicate obstruction, mass, or pancreatitis.

Retroperitoneal neoplasms

List of retroperitoneal tumors including pancreatic neoplasms, lymphangiomas, and cystic teratomas.

Cystic teratoma (ovarian-like)

Benign cystic lesion containing fat, calcifications, hair; can occur in pancreas similar to ovarian teratomas.

Pancreatic pseudocyst vs cystic neoplasm

Pseudocyst forms after pancreatitis; mucinous cystic neoplasms and IPMN are true cystic neoplasms with malignant potential.

Key imaging planes for pancreas

Transverse plane commonly used to identify the head/neck/body/tail and to locate vessels; longitudinal plane helps assess duct and ductal dilation.

Duodenum as a ‘lap of the pancreas’

The pancreatic head sits within the curve of the duodenum (the pancreas lies in the lap of the duodenum).

Pancreas location in the abdomen

Primarily in the epigastric region with the tail extending into the left hypochondriac region; head and uncinate lie posterior; the gland sits in the lap of the duodenum.

Uncinate process

Hook-like posterior projection of the pancreatic head that curves behind the superior mesenteric vessels.

Portal confluence

Confluence of the splenic vein and superior mesenteric vein forming the portal vein, located near the pancreas.

Splenic vein

Vein traveling posterior to the pancreas (body/tail) that joins the SMV to form the portal vein.

Superior mesenteric artery (SMA)

Arises from the aorta; courses near the pancreas and serves as a key ultrasound landmark; located anterior to the uncinate process.

Aorta

Major posterior vessel; lies posterior to the pancreas in many views and is a deep landmark in pancreatic imaging.

Common bile duct (CBD)

Duct carrying bile from the liver; courses near the head of the pancreas and joins with the pancreatic ducts to enter the duodenum.

Duct of Wirsung (main pancreatic duct)

Main pancreatic duct running the length of the pancreas; drains into the duodenum via the major papilla with the CBD.

Duct of Santorini (accessory pancreatic duct)

Accessory pancreatic duct, drains the head and may join Wirsung or drain separately into the duodenum (minor papilla).

Ampulla of Vater (hepatopancreatic ampulla)

Site where the pancreatic duct and CBD join and drain into the second part of the duodenum.

Duodenum parts (1–4) anatomy

Part 1 attaches to the stomach; Part 2 (descending) contains the major papilla; Parts 3 and 4 wrap around the pancreas and connect toward the SMA.

Celiac trunk branches

Three branches: left gastric, splenic, and common hepatic; the common hepatic gives rise to the GDA and proper hepatic artery.

Gastroduodenal artery (GDA)

Branch of the common hepatic that courses near the head of the pancreas and duodenum.

Left renal vein location

Between the SMA and the aorta; passes anterior to the aorta and posterior to the SMA.

Pancreatic ducts overview

Ducts from the pancreas (Wirsung and Santorini) join with the CBD and drain into the duodenum; normal Wirsung ~2 mm (2–3 mm common reference).

Normal pancreas size

Approximately 3 cm in greatest dimension; head is usually the largest portion.

Ultrasound technique tips (window)

Gas in stomach/duodenum can obscure imaging; use patient water intake and right lateral decubitus positioning to create a acoustic window.

Transverse pancreatic scan landmarks

Identify aorta, IVC, SMA, CBD, GDA, and portal confluence to orient the pancreatic head, body, and tail.

Head vs. neck vs. body vs. tail relations

Head lies near the duodenum; neck anterior to the portal confluence; body anterior to the aorta/celiac axis; tail extends toward the spleen and left kidney.

Pancreas in relation to stomach

Stomach lies anterior to the pancreas; pancreas lies posterior to the stomach and within the lap of the duodenum.

Normal duct size reference

Main pancreatic duct should be small; dilation (>2–3 mm depending on source) suggests obstruction.

Pancreatitis (acute) ultrasound features

Acute pancreatitis typically shows an enlarged gland; may be hypoechoic early with edema and potential complications.

Pancreatitis (chronic) ultrasound features

Coarse echotexture with calcifications, ductal dilation, possible pseudocysts, and gland contraction/atrophy over time.

Pseudocyst

Fluid collection that can occur after pancreatitis; lacks a true epithelial lining.

Annular pancreas

Congenital tissue ring around the second part of the duodenum that can cause obstruction.

Pancreatic divisum

Ductal division where Wirsung and Santorini do not fuse; two separate drainage routes; may predispose to pancreatitis.

Endocrine vs. exocrine pancreas

Endocrine: hormones released into blood (islets of Langerhans, insulin/glucagon/somatostatin). Exocrine: digestive enzymes released via ducts (lipase, amylase, proteases).

Islets of Langerhans cell types

Contain alpha and beta cells; beta cells produce insulin; other cells produce glucagon and somatostatin.

Pancreatic neuroendocrine neoplasms (islet cell tumors)

Functioning tumors such as insulinoma, gastrinoma, glucagonoma, somatostatinoma, and VIPoma; insulinoma is most common.

MEN Type 1 (Wermer syndrome)

Endocrine syndrome involving pituitary, parathyroid, and pancreatic islet cells; pancreas may be involved.

Pancreatic adenocarcinoma prognosis by location

Head tumors often present earlier due to duct/ductal obstruction (jaundice); tail tumors have poorer early detection and prognosis.

Courvoisier sign

Non-tender, palpable distended gallbladder with obstructive jaundice, commonly due to a pancreatic head mass.

Whipple procedure (pancreaticoduodenectomy)

Surgical removal of the pancreatic head and duodenum with reconstruction: pancreaticojejunostomy, choledochojejunostomy, and gastrojejunostomy; pylorus-preserving variant exists; usually open surgery.

Lymph nodes and metastasis in pancreatic cancer

Lymphadenopathy around the aorta is common with pancreatic cancer and usually indicates advanced disease; liver metastasis commonly checked.

Lesser common pancreatic cystic lesions

Serous cystadenoma (microcystic, benign), mucinous cystadenoma (macrocystic), intraductal papillary mucinous neoplasm (IPMN).