2. Embryology
⢠Develops from endoderm of primitive duodenum.
⢠Develops in two parts âdorsal part and ventral part
⢠Dorsal part/anlage forms whole body, neck and tail of gland, together
with part of head.
⢠ventral anlage develops as two separate buds from hepatic diverticulum.
⢠The left ventral bud atrophies, and right ventral bud persist to form head
and uncinate process
3. Normal anatomy
⢠Unpaired accessory digestive gland.
⢠Has both exocrine and endocrine functions.
⢠Length:-15 to 25 cm
⢠Height- 3 to5 cm
⢠Thickness-1.5 to 3.5 cm
⢠Weight-70to 110 gms.
4. ⢠Dorsal pancreatic segment grows posteriorly into dorsal mesentry,
and ventral analge develop as an outpouching from the base of
hepatic diverticulum as grows in the ventral mesentry.
6. ⢠Final stage of pancreatic duct maturation entails fusion of the two
systems.
7. ⢠Topography
Pancreas lies in anterior compartment of retroperitoneum, the anterior pararenal
space.
Pancreatic head-has constant relationship with duodenum with is right lateral
border nestled in duodenal sweep.
Pancreatic neck-lies anterior to confluence of splenic and SMV.
Pancreatic body-arches anteriorly and laterally to cross the spine
Pancreatic tail-not well demarcated from body as it extends to splenic hilum.
8. ⢠Position of pancreas
Head-lies at the level of L1-2 vertebra.
Body-crosses the spine at L1
Tail-located more superiorly in the region of splenic hilum
⢠Axis of pancreas
20 degree in relation with transverse plane
9. Relations of pancreas
⢠Head
Superior border-1st part of duodenum, superior pancreaticoduodenal artery.
Inferior bordrer-3rd part of duodenum, inferior pancreaticoduodenal artery.
Right lateral boredr-2nd part of duodenum, terminal part of bile duct
Anterior surface- transverse colon, 1st part of duodenum
Posterior surface- IVC, right renal vein, right crus of diaphragm.
11. ⢠Body
Anterior- stomach and lesser sac.
Superior-coeliac trunk, hepatic artery, splenic artery.
Inferior- SMA
Posterior- aorta , left crus of diaphragm,left kidney, left suprarenal
gland,renal vessels,splenic vein.
12. ⢠Tail
Lies in lienorenal ligament , together with splenic vessels it come in
contact with lower part of spleen .
13. Pancreatic duct
⢠Arise from tail of pancreas and receives 20-35 tributaries .
⢠At the level of major papilla ,MPD (duct of wirsung ) courses
horizontally to join CBD forming ampulla of vater
⢠Accessory pancreatic duct of santoniri drains superior and anterior
portion of head of pancreas.
14. Arterial supply
⢠Arterial blood supply arise from celiac trunk and SMA.
⢠Splenic artery.
⢠Superior pancreaticoduodenal artery( celiac trunk)
⢠Inferior pancreaticoduodenal artery(SMA)
16. Lymphatics
⢠Lymph nodes of pancreas are distributed along major vessels.
⢠Anatomy of lymphatics suggest that partial removal of pancreas for
cancer may not be sufficient because of direct connection between
different lymphatic chains.
⢠Head and neck drains into ventral and dorsal pancreaticoduodenal
group LN
⢠Body and tail drains into pancreaticosplenic LN.
⢠Efferents to coeliac and superior mesenteric LN.
17. Radiological techniques
⢠Plain radiographs
Plain radiographs obtained on the patients with suspected pancreatic
disease to exclude other conditions such as obstruction or perforated
duodenal ulcers that may stimulate pancreatitis.
Oblique view helpful in patients with chronic pancreatitis to detect
calcifications that may be obscured by spine in AP view.
18. Contrast study
⢠The posterior gastric wall , distal duodenum, duodenojejunal junction
can be abnormal with the lesions of pancreatic body and tail.
⢠Greater curvature, medial aspect of descending duodenum provide
clue for lesions arising from pancreatic head and neck.
⢠Ba enema examination may reveal abnormalities of colon caused by
disease spread via transverse mesocolon.
19. USG
⢠It is fast ,safe and inexpensive
⢠It is best performed on fasting patient to reduce amount of gas and
food in overlying bowel.
⢠Real time equipment with transducer of frequency 5-8 MHz should
be used.
20. ⢠Examination techniques.
Scan of pancreas should first be performed with patient supine and
transducer turned into modified transverse plane angled cephalad
towards spleen.
Long axis of pancreas seen anterior to splenic vein and confluence of
SMV and splenic vein.
21. ⢠Parasagittal scan should be begin where the portal vein merges with
longitudinally oriented SMV.
⢠The neck of pancreas is seen anterior to this confluence.
⢠Uncinate process lies posterior SMV
22. ⢠Having the patient drink four 6-oz degassed water can provide
sonographic window for improved visualization of body and tail
⢠Deep inspiration causes liver to move inferiorly over pancreas ,
caudally displacing gas filled bowels.
⢠IV glucagon 0.3 mg stop peristalsis and improve water retention in
stomach and pancreas.
⢠Scanning patient in erect position is also helpful as it as it allow the
liver to descend over the pancreas, displacing the bowel loops
inferiorly. It also cause gas in stomach and duodenum to raise above
the level of pancreas.
23. Normal findings on USG
⢠Maximum normal anteroposterior diameter of pancreatic head is 2.6
cm and body 2.2 cm.
⢠Tail is much variable in size and shape
⢠Pancreas is proportionately larger in young people and it decrease in
relative size with age.
⢠Borders of pancreas are usually smooth in youth and become
irregular with age.
24. ⢠Echogenicity of pancreas
Echogenicity is high throughout its substance
Pancreatic tissue echotexture is usually coarse, more inhomogeneous,
more echogenic than that of liver.
25. ⢠MPD
It is identified sonographically in 2/3rd of patients as an anechoic space
surrounded by hypoechoic lines resembling trolley tracks.
The maximal inner diameter is 2 mm; when it is larger, an obstructing
mass, stricture or stone must be suspected.
27. CT
⢠Best single noninvasive technique for imaging of pancreas.
⢠It is unaffected by bowel gas or large body habitus is widely available
and relatively easily performed.
28. CT scan protocols for pancreas.(16 slice)
Precontrast detector collimation 1.5mm
image thickness 5mm
Injection contrast volume(300mg/ml) 125ml
injection rate 4-6ml/sec
Arterial phase(CTA) scan delay 15 sec
detector collimation 0.75 mm
image thickness 1 mm
Parenchymal phase scan delay 35-45 sec
detector collimation 0.75 mm
image thickness 2 mm
Portal venous phase scan delay 70 sec
detector collimation 0.75 mm
image thickness 2-3 mm
29. ⢠Precontrast phase-pancreatic calcification, CBD calcification
⢠CTA -surgical planning.
⢠Parenchymal phase-maximal enhancement of pancreas, helps in
identifying hyper vascular neuroendocrine tumor hypo vascular
adenocarcinoma
⢠Portal phase - focal lesions and assessment of portal venous
structure, liver for metastasis.
30. ⢠Water or low density oral contrast medium given 30 min prior to
scanning
⢠Negative contrast medium will not obscure CBD stones and helps in
assessing bowel wall involvement
31. Size ,Shape and Density on CT
⢠Maximum normal diameters
Head- 3 cm
Body-2.2 cm
Tail- 2.8 cm
⢠Attenuation of gland is similar spleen and muscles but less than liver
on noncontrast scan.
32. MRI
⢠Modality of choice in to evaluate the pancreas for small tumors.
⢠Pancreas appears as smooth or lobulated and may blend in with
surrounding retroperitoneal fat if there is fatty infiltration.
33. MRCP
⢠Heavily T2 weighted sequence in which fluid filled ducts stand out from
surrounding low signal intensity tissue.
⢠Postprocessing using maximum-intensity profile technique allow
visualization from multiple prospective, giving appearance similar to ERCP
⢠Normal anatomy on MRCP
Intrahepatic bile ducts are depicted as high signal intensity branching,
tubular structure against the low signal intensity background of solid
parenchymal organs
Intrahepatic bile ducts can be distinguished from low signal portal vein ,
which contain rapidly flowing blood.
36. Pancreas Divisum
Pancreas divided in two separate parts as a result of an absent or
incomplete fusion of dorsal and ventral anlage.
Pancreatic head and uncinate process are drained by duct of Wirsung
through minor papilla , the body and tail are drained by duct of
santorini through major papilla
Clinical findings-this anomaly may contribute to recurrent of
pancreatitis
37. ⢠Radiological findings
CT
Two distinct pancreatic moieties or unfused ductal system is identified
MRCP
Heavily T2 weighted, two dimensional , fast spin- echo sequences
accurately depict pancreatic ductal anomaly
When T1 weighted sequences with fat suppression are performed,
MRCP allows visualization of pancreatic duct as well as parenchyma.
38. Annular Pancreas
⢠Annulus is flat band of pancreatic tissue completely encircling second
part of duodenum.
⢠In normal pancreatic development, ventral anlage develops as two
separate buds from hepatic diverticulum.
⢠The left ventral bud atrophies, and right ventral bud persist to form
head and uncinate process
Three theories concerning the formation of annular pancreas
1.Hypertrophy of both ventral and dorsal ducts
2.Adherance of ventral duct to duodenum
3.Hypertrophy or adherence of left bud
39. ⢠Clinical findings
ďSymptoms related to duodenal obstruction
ďVomiting on first day of life
ďAntecedent history of polyhydramnios and other manifestation of
fetal GIT obstruction
40. ⢠Radiological findings
Plain radiographs-double bubble sign
Barium studies -extrinsic eccentric defect on medial margin of 2nd
part of duodenum
41. ⢠USG- non specific enlargement of pancreatic head.
⢠CT-shows enlargement of pancreatic head that has central region of
high attenuation representing contrast material within narrowed
duodenal segment.
⢠MRI- T1 âweighted sequence shows normal pancreatic tissue
encircling the duodenum.
42. Ectopic pancreatic Tissue
⢠Heteroplastic differentiation of part of embryonic ectoderm that do
not normally produce pancreatic tissue.
⢠Ectopic rest of pancreatic tissue occurs in gastric antrum, proximal
Portion of duodenum
Majority of cases are asymptomatic and found incidentally.
43. ⢠Radiologic findings
Barium contrast study
-broad based, smooth intramural lesion.
-central niche / umbilication is diagnostic, represent the orifice of
rudimentary duct into which ectopic pancreas empties .
