GASTROINTESTINAL RADIOLOGY

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GASTROINTESTINAL RADIOLOGY

SPLENIC LYMPHOMA:

lymphoma> leukemia

HL>NHL

LESSER SAC HERNIA:

10%. These occur through the foramen of Winslow. Ileum>jejunum for foramen of Winslow. Paraduodenal hernias are the most common. These are the Waldeyer, and Lanzert hernias. Lanzert is on the left. Waldeyer is on the right. Lanzert is more common thanWaldeyer. Ie 3/4 are Lanzert and 1/4 are Waldeyer

ESOPHAGEAL STRICTURES:

long segment: NGT, lye ingestion

short segment: Baretts, squamous cell ca, epiderm bullosa

GLUCAGON:

is absolutely contraindicated in pheo and in pts with insulinoma as it can cause hypertensive crisis in the former and precipitous glucose drop in the latter. It is also absolutely contraindicated in allergy. The anticholinergic buscopan is contraindicated in pts with glaucoma

ABDOMINAL TRAUMA:

spleen is the most commonly injured organ

SOME MESENTERIC ANATOMY

first lets look at the neonate—At birth, when respiration is established, an increased amount of blood from the pulmonary artery passes through the lungs, and the placental circulation is cut off. The foramen ovale is closed by about the tenth day after birth: the valvular fold above mentioned adheres to the margin of the foramen for the greater part of its circumference, but a slit-like opening is left between the two atria above, and this sometimes persists. The ductus arteriosus begins to contract immediately after respiration is established, and is completely closed from the fourth to the tenth day; it ultimately degenerates into an impervious cord, the ligamentum arteriosum, which connects the left pulmonary artery to the arch of the aorta.

The right gastric artery arises from the hepatic, above the pylorus, descends to the pyloric end of the stomach, and passes from right to left along its lesser curvature, supplying it with branches, and anastomosing with the left gastric artery.

The gastroduodenal artery is a short but large branch, which descends, near the pylorus, between the superior part of the duodenum and the neck of the pancreas, and divides at the lower border of the duodenum into two branches, the right gastroepiploic and the superior pancreaticoduodenal. Previous to its division it gives off two or three small branches to the pyloric end of the stomach and to the pancreas.

The right gastroepiploic artery runs from right to left along the greater curvature of the stomach, between the layers of the greater omentum, anastomosing with the left gastroepiploic branch of the lienal artery. Except at the pylorus where it is in contact with the stomach, it lies about a finger's breadth from the greater curvature. This vessel gives off numerous branches, some of which ascend to supply both surfaces of the stomach, while others descend to supply the greater omentum and anastomose with branches of the middle colic.

The superior pancreaticoduodenal artery descends between the contiguous margins of the duodenum and pancreas. It supplies both these organs, and anastomoses with the inferior pancreaticoduodenal branch of the superior mesenteric artery, and with the pancreatic branches of the lienal artery.

The cystic artery usually a branch of the right hepatic, passes downward and forward along the neck of the gall-bladder, and divides into two branches, one of which ramifies on the free surface, the other on the attached surface of the gall-bladder.

The Lienal or Splenic Artery, the largest branch of the celiac artery, is remarkable for the tortuosity of its course. It passes horizontally to the left side, behind the stomach and the omental bursa of the peritoneum, and along the upper border of the pancreas, accompanied by the lienal vein, which lies below it; it crosses in front of the upper part of the left kidney, and, on arriving near the spleen, divides into branches, some of which enter the hilus of that organ between the two layers of the phrenicolienal ligament to be distributed to the tissues of the spleen; some are given to the pancreas, while others pass to the greater curvature of the stomach between the layers of the gastrolienal ligament. Its branches are pancreatic, short gastric, and left gastroepiploic.

The pancreatic branches are numerous small vessels derived from the lienal as it runs behind the upper border of the pancreas, supplying its body and tail. One of these, larger than the rest, is sometimes given off near the tail of the pancreas; it runs from left to right near the posterior surface of the gland, following the course of the pancreatic duct, and is called the arteria pancreatica magna. These vessels anastomose with the pancreatic branches of the pancreaticoduodenal and superior mesenteric arteries.

The short gastric arteries consist of from five to seven small branches, which arise from the end of the lienal artery, and from its terminal divisions. They pass from left to right, between the layers of the gastrolienal ligament, and are distributed to the greater curvature of the stomach, anastomosing with branches of the left gastric and left gastroepiploic arteries.

The left gastroepiploic artery the largest branch of the lienal, runs from left to right about a finger’s breadth or more from the greater curvature of the stomach, between the layers of the greater omentum, and anastomoses with the right gastroepiploic. In its course it distributes several ascending branches to both surfaces of the stomach; others descend to supply the greater omentum and anastomose with branches of the middle colic.

The superior mesenteric artery is a large vessel which supplies the whole length of the small intestine, except the superior part of the duodenum; it also supplies the cecum and the ascending part of the colon and about one-half of the transverse part of the colon. It arises from the front of the aorta, about 1.25 cm. below the celiac artery, and is crossed at its origin by the lienal vein and the neck of the pancreas. It passes downward and forward, anterior to the processus uncinatus of the head of the pancreas and inferior part of the duodenum, and descends between the layers of the mesentery to the right iliac fossa, where, considerably diminished in size, it anastomoses with one of its own branches, viz., the ileocolic. In its course it crosses in front of the inferior vena cava, the right ureter and Psoas major, and forms an arch, the convexity of which is directed foward and downward to the left side, the concavity backward and upward to the right. It is accompanied by the superior mesenteric vein, which lies to its right side, and it is surrounded by the superior mesenteric plexus of nerves. Branches.—Its branches are: inferior pancreaticoduodenal, ileocolic, intestinal, right colic, middle colic.

The Inferior Pancreaticoduodenal Artery is given off from the superior mesenteric or from its first intestinal branch, opposite the upper border of the inferior part of the duodenum. It courses to the right between the head of the pancreas and duodenum, and then ascends to anastomose with the superior pancreaticoduodenal artery. It distributes branches to the head of the pancreas and to the descending and inferior parts of the duodenum.

The Intestinal Arteries arise from the convex side of the superior mesenteric artery. They are usually from twelve to fifteen in number, and are distributed to the jejunum and ileum. They run nearly parallel with one another between the layers of the mesentery, each vessel dividing into two branches, which unite with adjacent branches, forming a series of arches, the convexities of which are directed toward the intestine. From this first set of arches branches arise, which unite with similar branches from above and below and thus a second series of arches is formed; from the lower branches of the artery, a third, a fourth, or even a fifth series of arches may be formed, diminishing in size the nearer they approach the intestine. In the short, upper part of the mesentery only one set of arches exists, but as the depth of the mesentery increases, second, third, fourth, or even fifth groups are developed. From the terminal arches numerous small straight vessels arise which encircle the intestine, upon which they are distributed, ramifying between its coats. From the intestinal arteries small branches are given off to the lymph glands and other structures between the layers of the mesentery.

The Ileocolic Artery is the lowest branch arising from the concavity of the superior mesenteric artery. It passes downward and to the right behind the peritoneum toward the right iliac fossa, where it divides into a superior and an inferior branch; the inferior anastomoses with the end of the superior mesenteric artery, the superior with the right colic artery. The inferior branch of the ileocolic runs toward the upper border of the ileocolic junction and supplies the following branches: (a) colic, which pass upward on the ascending colon; (b) anterior and posterior cecal, which are distributed to the front and back of the cecum; (c) an appendicular artery, which descends behind the termination of the ileum and enters the mesenteriole of the vermiform process; it runs near the free margin of this mesenteriole and ends in branches which supply the vermiform process; and (d) ileal, which run upward and to the left on the lower part of the ileum, and anastomose with the termination of the superior mesenteric.

THINGS THAT KEEP ON GETTING ASKED ON THE EXAM (see representative CT scan images below):

smv comes in front of sma and to the right of it

3rd part of duodenum passes behind sma

l renal vein also passes behind sma

the uncinate process of the pancreas is posterior to the smv

left renal vein is anterior to aorta

right renal artery is posterior to the ivc

renal vein and artery are anterior to the ureters (bridge over troubled waters)

GDA is anterior to the portal vein

gastroepiploic artery is anterior to the portal vein and the CBD

the common hepatic duct is anterior to the right, left and common hepatic artery

some things that are retrocaval include the right renal artery and medial right adrenal gland

SVC is anterior to the R PA

common iliac artery is anterior to the common iliac vein

caudate lobe of liver is cephalad to the portal vein

SVC (is anterior to the aorta and if u think vena cava which has 8 letters it reminds you of T8) is anterior to the esoph and aorta

esophagus and vagus are the middle opening in the diaphragm (esophagus = 10 letters which is T10)

most posterior is aorta/azygous/hemiazygous which enters the diaphragm at the T12 level

Slice 16

Slice 15

THE STORY ON LOBES AND LIGAMENTS OF THE LIVER: this is something that I keep on forgetting.

LOBES:

The right lobe is much larger than the left; the proportion between them being as six to one. It occupies the right hypochondrium, and is separated from the left lobe on its upper surface by the falciform ligament; on its under and posterior surfaces by the left sagittal fossa; and in front by the umbilical notch. It is of a somewhat quadrilateral form, its under and posterior surfaces being marked by three fossæ: the porta and the fossæ for the gall-bladder and inferior vena cava, which separate its left part into two smaller lobes; the quadrate and caudate lobes. The impressions on the right lobe have already been described.

The quadrate lobe is situated on the under surface of the right lobe, bounded in front by the anterior margin of the liver; behind by the porta; on the right, by the fossa for the gall-bladder; and on the left, by the fossa for the umbilical vein. It is oblong in shape, its antero-posterior diameter being greater than its transverse.

The caudate lobe is situated upon the posterior surface of the right lobe of the liver, opposite the tenth and eleventh thoracic vertebræ. It is bounded, below, by the porta; on the right, by the fossa for the inferior vena cava; and, on the left, by the fossa for the ductus venosus. It looks backward, being nearly vertical in position; it is longer from above downward than from side to side, and is somewhat concave in the transverse direction. The caudate process is a small elevation of the hepatic substance extending obliquely lateralward, from the lower extremity of the caudate lobe to the under surface of the right lobe. It is situated behind the porta, and separates the fossa for the gall-bladder from the commencement of the fossa for the inferior vena cava.

The left lobe is smaller and more flattened than the right. It is situated in the epigastric and left hypochondriac regions. Its upper surface is slightly convex and is moulded on to the diaphragm; its under surface presents the gastric impression and omental tuberosity, already referred to page 1189.

LIGAMENTS:

The liver is connected to the under surface of the diaphragm and to the anterior wall of the abdomen by five ligaments; four of these—the falciform, the coronary, and the two lateral—are peritoneal folds; the fifth, the round ligament, is a fibrous cord, the obliterated umbilical vein. The liver is also attached to the lesser curvature of the stomach by the hepatogastric and to the duodenum by the hepatoduodenal ligament.

The falciform ligament is a broad and thin antero-posterior peritoneal fold, falciform in shape, its base being directed downward and backward, its apex upward and backward. It is situated in an antero-posterior plane, but lies obliquely so that one surface faces forward and is in contact with the peritoneum behind the right Rectus and the diaphragm, while the other is directed backward and is in contact with the left lobe of the liver. It is attached by its left margin to the under surface of the diaphragm, and the posterior surface of the sheath of the right Rectus as low down as the umbilicus; by its right margin it extends from the notch on the anterior margin of the liver, as far back as the posterior surface. It is composed of two layers of peritoneum closely united together. Its base or free edge contains between its layers the round ligament and the parumbilical veins.

The coronary ligament consists of an upper and a lower layer. The upper layer is formed by the reflection of the peritoneum from the upper margin of the bare area of the liver to the under surface of the diaphragm, and is continuous with the right layer of the falciform ligament. The lower layer is reflected from the lower margin of the bare area on to the right kidney and suprarenal gland, and is termed the hepatorenal ligament.

The triangular ligaments are two in number, right and left. The right triangular ligament is situated at the right extremity of the bare area, and is a small fold which passes to the diaphragm, being formed by the apposition of the upper and lower layers of the coronary ligament. The left triangular ligament is a fold of some considerable size, which connects the posterior part of the upper surface of the left lobe to the diaphragm; its anterior layer is continuous with the left layer of the falciform ligament.

The round ligament is a fibrous cord resulting from the obliteration of the umbilical vein. It ascends from the umbilicus, in the free margin of the falciform ligament, to the umbilical notch of the liver, from which it may be traced in its proper fossa on the inferior surface of the liver to the porta, where it becomes continuous with the ligamentum venosum.

In the figure below, note that the caudate and IVC touch and are posteriorly located structures. They are also posterior in relation to the quadrate which happens to be an anterior structure

WHAT IS PELIOSIS HEPATITIS?

Peliosis hepatitis: blood filed vascular lesion in the liver associated with baciliary angiomatosis in hiv patients: they have fever and jaundice

BIT ON HERNIAS

right sided inguinal hernias usually contain small bowel whereas sigmoid colon usually prolapses into the left side

BARETTS ULCERATIONS:

the fine reticular ulcerations are deep

HEPATIC ADENOMA ENHANCEMENT:

hepatic adenomas enhance during the arterial phase of CECT

WHAT IS THE MOST COMMON FUNCTIONING ISLET CELL TUMOR?

insulinoma. It demonstrates strong enhancement on CECT. Unlike the other functioning pancreatic islet cell tumors, insulinomas occur with equal frequency throughout the pancreas

MORE ON TOXIC MEGACOLON:

toxic megacolon rarely ocurrs with pseudomembranous colitis

POLYPOSIS SYNDROMES

while Peutz Jeghers is a disease with hamartomatous polyps, there is still a risk of malignancy as 2-3 percent have adenomatous polyps in the stomach, duodenum and colon. Think TGF for adenomas (ie Turcot, Gardners, Familial polyposis coli)

For the polyposis syndromes, this is helpful:

hereditary turcot (AR) and Cronkite Canada (NH). All the rest are AD. Then I think of thank god its friday or TGF for turcot, gardeners and familial polyposis coli which are the ones that contain adenomatous polyps. All the rest contain hamartomatous polyps except juvenile polyposis coli which consists of a single inflammed polyp in the rectosigmoid region and presents with GI bleeding..

Other things useful are: Cowden (cow = milk=breast; women with this syndrome have an increased incidence of breast ca; also, women have more incidence of thyroid lesions so thyroid lesions). Also, in addition to breast carcinoma, Cowden's also has mucocutaneous lesions, and hamartomatous polyps of the gastrointestinal tract. For Cronkite Canada, they have more brownish hyperpigmentation of the skin and nail atrophy in addition to alopeciae. They end up dying soon after onset due to a severe protein losing enteropathy which results in thickened gastric folds among other things. CC is a disease of older adults (>60years) and it is rapidly fatal in women, but has a tendency to remission in men. Turcot have more brain tumors; usually supratentorial GBM and medulloblastoma. Peutz Jeghers, like Cowden's has multiple hamartomas and similarly they have pigmented mucocutaneous lesions ( I dont think the ones in Cowdens are pigmented though). Gardner syndrome is an autosomal dominant disease that is characterized by the triad of colonic polyps, osteomas (most commonly in the frontal sinus, but I need the check on this), and soft tissue tumors (eg. desmoid tumors, epidermoid inclusion cysts, fibroma, lipoma, leiomyoma).

MALIGNANCY IN ADENOMATOUS POLYPS:

risk of malignancy of adenomatous polyps based on size:

<5mm=0%

5-9mm=1%

10-20mm=10%

>20mm=50%

HEMOCHROMATOSIS:

1 HC: get Fe in the hepatocytes of the liver. Also panc involved

In 2 HC: Kupffer cells of liver involved. Spleen, LN ie RES is involved

FOLDS AND RECESSES:

The Valves of Houston is another term for rectal folds. The Twining recess also known as the "diamond sign" is a temporary triangular tent-like cleft in the midportion of the pyloric canal with its apex pointing inferiorly due to mucosal bulging between two separated hypertrophied muscle bundles on the greater curvature side of the pyloric channel. This sign is seen in hypertrophic pyloric stenosis. Morgagni’s columns are a number of vertical ridges in the mucous membrane of the upper half of the anal canal. A Schatzki’s ring is a contraction or incomplete diaphragm in the lower third of the esophagus which is occasionally symptomatic. The valves of Heister are a series of crescentic folds of the mucous membrane in the upper part of the cystic duct arranged in a spiral manner.

INFECTIOUS CAUSES OF CHOLANGITIS IN PTS WITH HIV:

Cholangitis in a pt with hiv is caused by cryptosporidium or cmv or both. Can also be caused by hiv virus.

PSC VS PBC:

Primary schlerosing cholangitis: strictures of both the intra and extrahepatic bile ducts

Psc:

Male > female. The differential for other conditions which cause an appearance similar to PSC is: recurrent biliary tract infections, post op patients with complications, and pts with hiv. The most common cause of this appearance worldwide is A. Lumbricoides infection.

Things which are associated with PSC infection are: IBD usually CD, retroperitoneal fibrosis, ascending cholangitis after biliary surgery, aids and parasitic infection.

Pbc:

Female>male. Pbc has classic "tree in winter" appearance.

SOME MORE CAUSES OF GB HYDROPS:

Tpn, hiv and cholecystitis all cause hydrops

EFFECT OF PANCREATIC HORMONES ON SPHICTER OF ODDI:

Glucagons relaxes the sphincter of oddi and causes relaxation of the bowel. It is contraindicated in pheochromocytoma

CCK causes contraction of the gb but relaxes the sphincter

MALLORY WEISS VS VOORHAVE:

76% of Mallory weiss tears ocurr below the GEJ involving venous plexus. Single longitudinal tear.

Voorhave do not have hematemesis. Bleed into chest. 2-5 cm rent 2-3 cm above the GEJ

BREAKDOWN ON ESOPHAGEAL CA:

esophageal carcinoma: 81-95% scc

and 4-19% adenoca

SMALL BOWEL LYMPHOMA:

lymphoma:

stomach>small bowel

ESOPHAGEAL VARICES:

downhill varices develop when the SVC is obstructed below the level of the azygous vein takeoff so that the collaterals are most developed in the upper half of the esophagus

GI DUPLICATIONS:

gi duplications are most common in the ileum and are on the mesenteric side

WHAT CAUSES NARROW SEGMENT ESOPH NARROWING?

baretts and epidermolysis bullosa cause narrow segment narrowing

LIVER HEMANGIOMAS:

hemangiomas are most common in the right lobe of the liver

CELL TYPE OF CHOLANGIOCARCINOMA:

cholangio ca’s are adenoca’s

GI INFECTIONS IN HIV

mai and cryptosporidium affects ileum>colon

cmv and cocciomycosis affects colon>ileum

INFLAMMATORY AND INFECTIOUS INVOLVEMENT OF GUT AND ESOPHAGUS:

in schleroderma, the proximal one third (striated) of the esophagus remains normal while the distal two thirds (smooth) becomes patulous

giardiasis and whipples: involve mainly duodenum and jejunum and produce irregular fold thickening

Behcets is a multisystem disease M>F that includes buccal and genital ulcerations, occular lesions and skin lesions. There can be GI ulcerations from mouth to anus. It is not associated with GI submucosal nodules

WHIPPLES:

irregular fold thickening of prox SB and low density mesenteric lymph nodes is classic

HSP AND BOWEL WALL THICKENING:

hsp is associated with regular bowel wall fold thickening due to mucosal hemorrage

regarding choledochal cysts:

A choledochal cyst refers to a congenital dilatation of a segment of the biliary ducts. The pathogenesis of the dilatation is not clearly understood but may be related to abnormal reflux of pancreatic enzymes causing inflammation and bile duct dilatation. Type I is most common and appears as a rounded widening of the common bile duct. Type II is least common and appears as normal calibaer common bile duct with diverticula. Type III is a cystic dilatation at the ampulla of Vater, also known as a choledochocele. Type IVA are multiple cystic dilatations of the intra- and extrahepatic bile ducts. Type IVB appears as multiple dilations of extrahepatic bile ducts. Type V is also known as Caroli’s disease. The majority of cysts are diagnosed in patients during early childhood. Complications include cholangitis, biliary calculi, biliary obstruction and carcinoma. So in summary then:

type 1 is the most common (80-90%) and involves fusiform dilatation of the CBD only

Type 2 is a cbd diverticula and is the least common (2%)

type 3 is a choledochocele and occurs in 3%

type 4b is extrahepatic ductal cysts while 4a is both intra and extra.

type 5 is Caroli disease which is intrahepatic involvement only

note there are 3 types of type 1:

and this figure (Weisleder) shows the type 2, 3, 4 and 5 lesions:

BILIARY CYSTADENOMAS:

these are rare. F>M (4:1). Caucasian. Premalignant. 4.6% of all intrahepatic cysts of bile duct origin. The peak incidence is in the 5th decade. They are multiloculated with a thick capsule. They derive from ectopic rests of biliary tissue and have an appearance like mucinous tumors of pancreatic origin. They contain columnar epithelial gelatinous secretions

SPIGELIAN HERNIAS

Spigelian hernias occur because of weakness in the posterior layer of the transversalis fascia

MOST COMMON CA++ LIVER LESION:

Hydatid dz is the first consideration for any calcified lesion in the liver

PANCREATITIS:

Ca++ can occur in acute pancreatitis from the breakdown of fat

Colonic obstruction:

Ca 60-70 %

Tics 20%

Volvulus 5%

Other is from hernia, impaction

PNEUMATOSIS WITHOUT PERITONITIS:

Perforation of a jejunal tic can cause pneumatosis without peritonitis. It is associated with a high mortality

START OF THE CERVICAL ESOPHAGUS:

The cricopharyngeus impression is at c56 which is the start of the cervical portion of the esophagus

CAUSTIC ESOPHAGITIS:

The middle and lower third of the esophagus are affected more severely in caustic esophagitis as they are areas of holdup due to the aortic arch, l main bronchus and diaphragmatic hiatus etc

TUMOR SOURCES OF ACTH

Acth is produced by smlc, carcinoid of the thymus, medullary thyroid ca, and pheochromocytoma

PANCREATIC NEOPLASMS:

ORIGIN:

99% from exocrine portion of pancreas

1 % are from the acinar portion of the pancreatic gland a

0.1% are malignant ampullary tumor with ausually has a better prognosis than pancrreatic adenoca

CLASSIFICATION:

3 main types: (a) exocrine, (b) endocrine, and (c) nonepithelial

(A) EXOCRINE:

these can be classified as either ductal, acinar, or indeterminate origin.

ductal:

ductal adenocarcinoma makes up 90% of them of the exocrine pancreatic tumors. The second most common in the ductal category are cystic neoplasms (serous and mucinous) which make up 10-15%. The remainder comprise ductiectatic mucinous secreting tumor which synomymous with mucous hypersecreting carcinoma and solid and papillary neoplasm (found in young women with good prognosis). Incidentally, the cystic changes associated with vhl also fall under the "ductal" category

acinar:

acinar cell carcinoma makes up 1% of the pancreatic tumors and occur in the acinar portion of the gland

indeterminate:

the only one I know of is pancreaticoblastoma which is infantile pancreatic carcinoma

MORE DETAIL ON THE 2 MAIN DUCTAL EXOCRINE NEOPLASMS:

cystic neoplasms (mucinous and serous):

mucinous cystic neoplasm of panc (malig). less than 6 cysts that are greater than 20mm in diam. 20 % rim calcification. mucin. peripheral enhancement. younger patients. 95% in body or tail. serous is benign. has > 6 cysts that are < 20 mm. contains glycogen. central scar. amorphous starbursts of ca++. older pts. 70% in head of the pancreas.

ductal adenocarcinoma:

60% of them ductal adenocarcinomas occur in the head nd 35% are in the body and tail. The criteria for unresectability are if the sma, portal vein or proximal smv is encased, or if there is malignant ascites.

NOW ONTO THE ENDROCRINE VARIETY:

(B) pancreatic islet cell (endocrine) tumors:

first their cell of origin:

Insulinomas: beta

Glucagonomas: alpha

Gastrinomas: alpha

Somatostatinomas: delta

vipoma: delta

85% are functioning and 15% are non functioning. The non fnctioning ones occur most commonly in the head of the pancreas

In order of frequency of occurence:

insulinoma>gastrinoma>non functioning>glucagonoma>vipoma>somatostatinoma

Here is a breakdown on some of the features of the functioning islet tumors:

they are relatively vascular tumors and show homogeneous enhancement on gado enhanced T1 weighted images

insulinoma (most common) F>M, no predilection for any part of pancreas. However, majority of insulinomas are in the distal 2/3 of the pancreas

gastrinoma (second most common islet cell tumor): M>F, head/tail 1:1

glucagonoma F>M, body and tail

somatastatinoma F>M, head

VIPOMA F>M, body and tail (very rare)

location, location, location

for the ones in the headof the pancreas, think GS for gastrinoma and somatostatinoma

Other features to note:

the activity of glucagon is as follows d>j>s>c esophagus is not affected by glucagon

Panc islet cell tumors are apud. They are usually hyperechoic on us. Presence of Ca++ suggests malignancy

Somatostatinomas produce triad of steatorrea, diabetes melitis, and gallstones by inhibiting the pancreatic exocrine and endocrine function.

Glucagonomas produce diarrea, DM, and necrolytic rash

INCIDENCE OF MALIGNANT DEGEN OF PANCREATIC ISLET CELL TUMORS:

Malignant transformation with insulinomas is the least common, occurring in 5% to 10% of cases. For all of the others, malignant transformation occurs in more than 50% of cases, with nonfunctioning islet cell tumor and glucagonoma being associated with the highest incidence (approaching 80%). There are reports that somatostatinoma can be up to 90% but the usual quoted figure is around 67%:

insulinoma: 10 %

vipoma: 60 %

Gastrinoma: 60 %

Somatastatinoma: 67 %

Glucagonoma: 80 %

non funtioning: 80%

NOW TO CONFUSE THINGS MORE, ONTO (C) NONEPITHELIAL PANCREATIC NEOPLASMS:

the main types here are primary lymphoma, secondary lymphoma and mets. Primary lymphoma accounts for <1% of pancreatic neoplasms and secondary lymphoma appears as a large homogenous solid mass which may displace and stretch peripancreatic vessels. The main mets are rcc, melanoma, lung and breast

PANCREATIC LESION THAT IS CONFUSED WITH THE MUCINOUS CYSTIC NEOPLASM:

Commonly confused with mucinous cystic lesions is the intraductal papillary mucinous tumor. In these lesions, neoplastic epithelium produces mucin which results in pancreatic ductal dilatation, which may cause obstructive jaundice. While intraductal lesions communicate with the pancreatic duct, mucinous lesions do not. As these are invasive tumors, treatment is surgical resection.

this is what Micheal Steer MD from HMS has to say about them:
Intraductal papillary mucinous tumors — A ductal ectatic form of mucin-producing tumors can also occur. These tumors, referred to as intraductal papillary mucinous tumors or IPMTs, present as multifocal dilatations of smaller branch ducts that communicate with the main pancreatic duct. IPMTs can on occasion be diagnosed by the finding of thick mucin extruding from the papilla at the time of endoscopy. It can be found anywhere in pancreas; the area involved may range from several millimeters to several centimeters in size or even involve the entire ductal system. The cystic dilatations are lined by columnar epithelium which may show areas of papillary change, atypia, or obvious malignancy. IPMT is more common in men than women. Even if the initial lesion is benign, it has a high potential for malignant change

SOME THINGS THAT TS IS ASSOCIATED WITH:

TS is associated with both aml’s and pheos in addition to other things such as osteomas (ie bone islands)

THINGS WHICH STIMULATE GASTRIC ACID PRODUCTION BY PARIETAL CELLS:

Three endogenous chemicals stimulate the secretion of acid (HCL): acelycholine, gastrin and histamine. Gastrin is released from chief cells in the gastric antrum by the presence of food, alkanization of the gastric lumen, and gastrin releasing protein.

CAUSES OF PORTAL HTN:

There are two separate and sometimes overlapping classification systems for the causes of portal hypertension, using either the liver or the hepatic sinusoid as the reference point. The former classifies conditions into pre-hepatic, intrahepatic and posthepatic causes, while the latter divides conditions into presinusoidal, sinusoidal and postsinusoidal causes. However, the exact site of increased resistance in many intrahepatic causes of portal hypertension has recently been questioned, and it is likely that the predominant resistance sites could change according to the stage of some disease processes. For example, early primary biliary cirrhosis is thought to produce mainly presinusoidal hypertension, but as dense cirrhosis supervenes, sinusoidal hypertension becomes more important. Similarly, an early lesion of alcoholic liver disease, the central or terminal hyaline sclerosis, characterized by zone 3 fibrosis, would cause postsinuoidal hypertension, with sinusoidal hypertension predominating as cirrhosis becomes established.

PRESINUSOIDAL:

prehepatic:

splenic av fistula

splenic vein thrombosis

massive splenomegaly

intrahepatic:

sarcoidosis

schistosomiasis

nodular regenerative hypeplasia

idiopathic portal fibrosis

early PBC

chronic active hepatitis

myeloproliferative disorders

graft vs host disease

SINUSOIDAL

established cirrosis

active hepatis

POSTSINUSOIDAL

alcoholic terminal hyalin schlerosis

venooclusive disease

posthepatic:

budd chiari

membranous web

right heart failure

constrictive pericarditis

SPLENIC VS HEPATIC ENHANCEMENT:

splenic uptake precedes hepatic as splenic takes up during the arterial phase while hepatic is during the portal phase

HEPATIC LESION SCARS:

fibrolamellar is a true scar so is dark, dark on T1, T2 while FNH has edema in the scar which gives dark,bright

FNH AND HEPATIC ADENOMA:

both show F>M

fnh is more common than hepatic adenoma. hepatic hemangioma is the most common. fnh is not associated with OCP while hepatic adenoma is. The central scar of fnh contains bile ducts making it bright on T2 and low intensity on T1. Also the central scar of fnh is hypoechoic.In fnh, there are no normal portal venous structures and there is central and peripheral increased venous blood flow. The central scar of fnh enhances with contrast during the portal phase. 99mTcSC is the best for seeing fnh. 40% are cold, 50% are iso, and 10% are hotter than normal liver. It is interesting to note that 13% of fnh are multiple.

with adenoma, it shows as a defect on 99mTcSC, but 23% show mild increased uptake. Unlike fnh, this lesion is definitely associated with OCP. They are hypervascular and have low malignant potential and pain is usually from bleeding or rupture. They are also associated with glycogen storage diseases such as von Gierke. On HIDA, it is hotter than liver because it concentrates bile but does not contain any bile ducts to excrete the contrast so the contrast builds up to high concentrations. On MR, they are low signal on T1 and variable signal on T2 because of blood products.

WHERE DOES AIR IN THE BILIARY TREE GO TO:

in the supine patient, it rises into the left biliary tree which is the most superior location.

CALCIFIED LIVER METS:

endocrine pancreatic ca mets, mucinous pancreatic ca, osteosarc, melanoma, papillary thyroid, serous ovarian ca, mucinous ovarian ca, medullary thyroid ca. Note that mets are 20x more common than primary liver ca.

INVOLVEMENT OF LIVER WITH LYMPHOMA:

60% is due to HL and 40% is due to NHL. The most common pattern of involvement is diffuse infiltrative.

APPEARANCE OF HCC:

solitary (27-60%), multiple (15-25%) adn diffuse infiltative (10-15%). Ca++ in uncommon in HCC (2-9%) and more common in FLC (30-40%). The central scar of FLC is hypointense on T2 as it is true scar.

EMPHYSEMATOUS CHOLECYSTITIS:

emphysematous is not gangrenous but is a precursor to it. Gallstones are absent in emphysematous cholecystitis. M>F (2:1). It is 5x more common than gangrenous. Gangrenous occurs in 2-38% of pts with acute cholecystitis. 10% have perforation. Murphy is postitive in only 30%

ONE CAUSE OF SPLENOMEGALY THAT I DID NOT KNOW:

SLE. Other causes are portal htn, storage dz, lymphoma, leukemia, multiple myeloma, mets, thalassemia, early sickle dz, mononucleosis

MINOR PAPILLA:

pancreatic embryology: minor papilla is present in 60%

PBC VS PSC:

PBC has normal appearing extrahepatic ducts in contrast to PSC. Has tree in winter appearance of the intrahepatic ducts. Female>male.

RECTAL INVOLVEMENT BY IBD:

UC: 100 % rectal involvement

CD: 50% rectal involvement

PLUMMER VINSON::

Cervical esophageal webs

INCIDENCE OF CECAL VOLVULUS VS SIGMOID VOLVULUS:

Cecal volv: young

Sigmoid: old

DIAPHRAGMATIC HERNIA:

Patulous diaphragmatic hiatus: if > 3 cm

EVAC PROCTOGRAPHY:

Anorectal angle inc from 95 degrees to 180 on straining

WHICH 2 OF THE POLYPOSIS SYNDROMES HAVE THYROID INVOLVEMENT?

Cowdens, Juvenile polyposis coli

REGENERATING NODULES:

Etoh=micro 3 mm

Viral =macro 3-15 mm

ZOLLINGER ELLISON:

ZE ulcerations: 75 percent in the duodenum, 20 in the stomach, and 11 in the jejunum

GRADING SYSTEM FOR PANCREATITIS:

apache>8 or ransom > 4 is severe disease

CELIAC DZ:

duodenum, jejunum > ileum

CAUSES OF BULKY LAN IN HIV:

Kaposi is a cause of bulky retroperitoneal LAN in addition to lymphoma

GASTRIC ULCERS:

increased risk in nsaid, menetrier, ze, h.pylori but not in alcoholism

VENOUS MESTENTERIC ANATOMY:

R gastric goes to portal vein

L gastric goes to paraumbilical vein to lumbar veins to IVC

splenic vein goes to gastrorenal and splenorenal to renal vein to IVC

GI DUPLICATIONS:

most common in the the distal ileum, distal esophagus, stomach, and duodenum. They are on mesenteric side and most are non communicating

ACHALASIA:

in primary achalasia, symptom onset is insidious while in secondary eg to a esophageal or fundal tumor, it is characterized by more rapid onset of symptoms and odynophagia

INTERNAL vs EXTERNAL LARNGOCELE:

within the confines of the thyroid cartilage and thyroid membrane. The external protrudes through the thyrohyoid membrane

COUINARDS SEGMENTS (SEE BELOW):

Hepatic surgery, hepatic resection in particular, is based on a segmental anatomy described by Couinard in 1957. There are eight segments in all. The caudate lobe is segment I. The right and left liver are divided by the middle hepatic vein. The left liver segment II is divided from segments III and IV by the left hepatic vein. Segment II is posterior to the left hepatic vein. Segments III and IV are separated by the falciform ligament. Segments V through VIII compose the right liver.

LARYNGOCELE:

represents a dilated appendix of the laryngeal ventricle and is usually confined to the perilaryngeal space. They are thin walled and can contain fluid

EFFECT OF HERPES AND DRUGS ON THE ESOPHAGUS:

herpes and drug affect the upper and mid esophagus with superficial ulcer. Reflux causes shallow ulcers in the distal esophagus

GI INVOLVEMENT WITH LYMPHOMA:

stomach (82%)

ileum (15%)

colon (6%)

duodenum (2%)

MALIGNANCY IN THE SMALL BOWEL:

jejunum: adenocarcinoma is the most common

ileum: carcinoid is the most common, and lymphoma is second

mets can occur anywhere

DIVERTICULOSIS:

diverticulosis in 50% of people 80y

diverticulitis in 4-5% of people with diverticulosis

bowel obstruction in 10% of people with diverticulitis

INCARCERATED VS STRANGULATED HERNIAS:

incarcerated are irreducible and strangulated are ischemic and irreducible

CAVERNOUS HEMANGIOMA:

iso to hypo on T1 and markedly hyper on T2

BRUNNERS GLAND HYPERPLASIA:

in duodenal bulb, get brunners gland hyperplasis in a regular and nodular pattern. In heterotopic gastric mucosae, the nodules are varying sizes and polygonal

HCC TYPES:

A: spreading

B: expanding

C: multifocal, diffuse

GI PATHOGENS IN AIDS:

CMV is the most common GI pathogen in AIDS and colitis is the most common GI manifestation of CMV

WHIPPLES AND MAI:

can both look similar. Whipple has a fine nodularity in the small bowel with mesenteric LN's that are hypodense on CT. MAI has bulky retroperitoneal LN's like whipples.

2 MOST COMMON GI MALIGNANCIES IN AIDS:

nhl and kaposi

GI LYMPHOMA (once again):

stomach>small intestine>rectum>perianal>duodenum>colon

PHLEGMON VS ABSCESS:

phlegmon is a ST density in omentum or mesentary. It is solid. abscess is liquid

MOST COMMON SITE OF BOWEL INJURY IN BLUNT ABDOMINAL TRAUMA:

the most common site of GI injury is the jejunum. Most bowel injuries occur at points of fixation. Ie just beyond the ligament of Trietz

ANEURYSMS IN PANCREATITIS:

GDA aneurysms are the most common of all of them

PANCREATIC TRAUMA: contusion, laceration, transection. The radiographic features are: hematoma, non enhancing regions, peripancreatic stranding. Delayed complications: abscess, pseudocyst, fistula, pancreatic necrosis

MORE ON PANCREATIC NEOPLASMS (SEE ABOVE):

serous cystadenoma of panc has a capsule and is associated with VHL. It can have a central dense calcification. Solid and papillary neoplasm of the pancreas is found in adolescent girls and has a good prognosis

AGAIN MAJOR CAUSE OF BILE DUCT INJURY DURING LAPAROSCOPIC SURGERY:

mainly occurs in pts with normal biliary anatomy

PHARYNGEAL POUCH:

it is a lposterolateral outpouching through thyrohyoid membrane seen in trumpet blowers etc

LARYNGOCELE:

lateral outpouching of larngeal ventricle seen in blowers

POST OP BILIARY STRICTURE:

ischemia is the most common cause of post op biliary stricture from liver transplant. This is indicates HA thrombosis. It is more common in children than in adults due to the smaller size of the HA in children resulting in a more difficult anastomosis

LIVER STRAIGHT LINE SIGN:

it is from portal segmental vein occlusion

COLONIC ANGIODYSPLASIA:

it is antimesenteric. Telangiectasis with Rendu Osler Weber are in small bowel and not in colon. Note that ROW=HHT

CELLS IN THE STOMACH:

antrum contains all the G cells. Fundus and body contain all the parietal or acid secretory cells.The chief cells which are also in the fundus and body make trypsinogen

CT DENSITY OF LIVER:

on non enhanced CT, liver is more dense than spleen due to its high glycogen content

RADIOGRAPHIC IMITATOR OF UC:

salmonella (think salmonella and uc or suc(k) )

RADIOGRAPHIC IMITATOR OF CD:

yersinia

DDX OF ACHALASIA:

1ary achalasia, chagas, central and peripheral neuropathy, malignancy

SCLERODERMA:

the smooth muscle in the distal 1/2 to 2/3 of the esophagus is replaced by fibrous tissue, resulting in decreases esophageal motility. There is severely decreased LES tone resulting in reflux and peptic stricture formation

MENETRIERES:

usually get antral sparing

GASTRIC VARICES W/O ESOPHAGEAL VARICES:

this indicates splenic v thrombosis which is most commonly caused by pancreatitis or pancreatic ca. For downhill varices, mediastinal tumor or inflammatory dz are the usual cause

ORIGIN OF ZENKERS DIVERTICULUM:

these arise in the midline posterior and just proximal to the cricopharyngeus muscle

GI WATERHED AREAS:

the 2 areas are splenic flexure and rectosigmoid

VOORHAVE:

the tear occurs along the L posterior esophageal wall near the L diaphragmatic crus

INTERNAL HERNIAS:

majority are paraduodenal and result from failure of the mesentary to fuse with the peritoneum at the ligament of Trietz. Bowel herniation through the foramen of Winslow into the lesser sac is a less frequent occurrence

GASTRIC ADENOMATOUS POLY LOCATION:

most are located in the antrum. Both the adenomatous and hyperplastic type are common in pts with achlorhydria and chronic atrophic gastritis

PNEUMATOSIS:

1ary: gas collections are predominantly cystic

2ary: gas collections are more linear

HYDATIC CYSTS:

hydatid cysts from ecchinococcus are the most common cause of hepatic cysts worldwide. Can occur in the brain, lung, kidney, and bone. The risk of anaphylactic rxn from percutaneous aspiration is reduced with a very thin needle (22G). Ecchinococcus alveolaris is a solid, infiltrating, non specific mass and can look like a neoplasm

PRIMARY HC:

they usually present with cirrosis, DM, and hyperpigmentation

liver density seen in HC is also seen in amiodarone toxicity, glycogen storage dz, Wilsons. In 1 ary HC, the spleen is not involved

Good way to remember the position of the CBD, HV, and PV:

ie the CBD is on the same side as the GB

CONTENTS OF SMALL BOWEL MUCOSA:

contain lamina propria, lymphoid follicles, and kultchinsky cells which are another name for the argentaffin cells that give rise to carcinoids. It does not contain myenteric plexus cells; these are in the muscularis

ASSOCIATIONS WITH PSC:

usually involves fibrous obliteration of intra and extrahepatic bile ducts. Young M>F. It is associated with sicca complex, reidels struma, RPF, and mediastinal fibrosis

PNEUMATOSIS INTESTINALIS:

it has a preference for the jejunum

INTRAMURAL ESOPH PSEUDODIVERTICULOSIS:

m>f, 20% of pts are diabetic. 15% of pts are alcoholics. 34 - 48% are colonized with candida

ESOPHAGEAL TUMORS:

esophageal ca 80% SCC and 20% adenoca. SCC is more common in the upper esoph. Need a double contrast esophagram to see the z line. Plummer vinson is dysphagia, Fe deficiency anemia, mucosal lesions of the mouth, pharynx and esophagus

LMYMPHGRANULOMA VENEREUM:

is is caused by clamydia trachomatis in homosexual males. Gonococcal proctitis has a similar appearance

GI DUPLICATION:

most common in the teminal ileum on the mesenteric side

CARMEN MENISCUS SIGN AND KIRKLAND COMPLEX:

ulcer crater straddling the lesser curvature of the stomach

SCLERODERMA:

basal interstitial fibrosis and dilatation of the esophagus. The esophagus is involved in 90% and the lungs are the least likely to be involved. It is also associated with the CREST syndrome. The esop>small bowel>colon>stomach. There is an incompetent LES with decreased peristalsis and increased reflux into the dilated esophagus. There is small bowel atony, diln, malabsorption, pneumatosis, hidebound appearance, and pseudosacculations

SPRUE:

in non tropical sprue, get jejunization of the ileum and ilealization of the jejunum. As mentioned earlier, there are transient intucusseptions of small bowel which becomes flaccid and dilated. A moulage pattern is seen with the older contrast suspensions

DIFFICULTY WITH REMBERING SOME OF THE FOLDS CAN BE HELPED AS FOLLOWS:

anus = am = morgagni

pylorus = pt = twinning

CAUSES OF PNEUMOPERITONEUM WITHOUT PERITONITIS:

endoscopy, perforated jej tic (most common), therapeutic arterial embolization, perfed cyst or pneumatosis intestinalis, air tracking down form the mediastinum.

HAUSTRATION:

there is no haustration from the mid transverse colon to the rectum. The descending colon is mainly supplied by the IMA

ZOLLINGER ELLISONS:

the ulcerations occur in the proximal duodenum (75%), jejunum (11%), and stomach (20%). It is associated with the presence of gastrinoma