Block 3 GARQs

● Please identify four imaging modalities that you can use to visualize and evaluate vessels.

o 1) CT angiography, 2) MR angiography, 3) Intravascular Ultrasound, 4) Digital Subtraction Angiography

● Identify one potential cause of false-positive liver percussion (i.e. you interpret that the liver is larger than it actually is based on your exam).

o Right pleural effusion will cause you to start hearing dullness higher up than the liver actually is due to the fluid in the space. o Also, you would get a false-positive if there is an abdominal mass adjacent to the inferior border of the liver, it would make the inferior border appear lower upon percussion.

A "filter" can be placed in the inferior vena cava (IVC) of patients in whom a DVT develops and who have contraindications for anticoagulation therapy. The filter is usually introduced through the femoral vein. Why?

A deep vein thrombosis (DVT) is a blood clot (thrombus) that forms in a vein deep inside the body. A clot occurs when blood thickens and clumps together. In most cases, this clot forms inside one of the deep veins of the thigh or lower leg. A thrombus in a leg vein can break free, travel return to the heart via the IVC, and stick in a vessel in the lung. This can cause a blockage in the vessel called a pulmonary embolism. Pulmonary embolism can cause severe shortness of breath and even sudden death. An IVC filter is one method to help prevent pulmonary embolism. An IVC filter is a small, wiry device. When the filter is placed in your IVC, the blood flows past the filter. The filter catches blood clots and stops them from moving up to the heart and lungs. This helps to prevent a pulmonary embolism. The femoral vein passes through the femoral triangle in a superficial position that provides minimally invasive access. Thus, a catheter can be passed superiorly through the femoral vein, into the external iliac vein, into the IVC. Entry via the femoral vein is comfortable for the patient (versus a jugular approach), and it is easier to cannulate due to larger diameter and structural integrity.

● Define Morison's pouch and its boundaries.

Morrison's pouch - aka the hepatorenal recess, a potential space between the right kidney and liver. It is the posterosuperior extension of the subhepatic space, with the following boundaries: ■ Anterior: Right lobe of the liver & the gallbladder. ■ Posterior: Right kidney & right adrenal gland, second part of duodenum, hepatic flexure, & head of pancreas. ■ Inferior: transverse mesocolon. ■ Superior: Posterior layer of coronary ligament

● In a patient with a liver laceration, what is the preferential flow of blood within the peritoneal cavity? ● In a patient with a splenic laceration, what is the preferential flow of blood within the peritoneal cavity? Based on this, where should you look for the presence of blood?

Morrisons Pouch (hepatorenal) ○ Preferentially goes to the Subdiaphragmatic region due to abdominal pressure changes with breathing

Describe the arterial supply and venous drainage of the rectum.

Arterial Supply · Superior Rectal Artery (from IMA) supplies proximal rectum · Middle Rectal Arteries (from anterior internal iliac) supply middle and inferior rectum · Inferior Rectal Arteries (from internal pudendal) supply anorectal junction and anal canal Venous Drainage · Superior Rectal Veins drains into portal system · Middle Rectal Veins drains into systemic circulation · Inferior Rectal Veins drains into systemic circulation

● The figure below (Figure 5) is a splenoportogram performed with MRI. Does this highlight venous or arterial structures in the abdomen (which structures are brightest)? ● Please name the anatomic structures which are labeled with the letters A through G in this image. ● Please indicate the vessels in this image which ultimately drain into the main portal vein and identify them. ● Which type of contrast is used for MR imaging?

○ This image highlights venous structures from the spleen to the hepatic portal system. ○ A = hepatic portal vein ○ B = abdominal aorta ○ C = inferior vena cava ○ D = splenic vein ○ E = inferior mesenteric vein ○ F = superior mesenteric vein ○ G = left common iliac vein ○ Splenic, Superior Mesenteric, and Inferior Mesenteric Veins drain into the hepatic portal vein. ○ Gadolinium contrast media, which is administered intravenously, is used for MR imaging.

Below is an image obtained from a CT of the liver (Figure 10): ● Identify the liver segments 1, 3, 4, 5 and 6 on the image. ● Identify the portal vein, the hepatic veins and the IVC. ● Identify the stomach (St), colon (C) and spleen (Sp) in this image. ● Is this image acquired with intravenous contrast?

○ YES

Two distinct areas of the abdominal cavity are outlined in color in Figure 7 (below). Please identify the area outlined in blue. Please identify the area outlined in yellow. ● What is the term that describes an abnormal accumulation of this fluid in the peritoneal cavity? ● When an accumulation of fluid in the abdominal cavity is identified, using CT, how do you determine whether this fluid is simple "water-equivalent fluid" or blood? ● What is the term that describes blood collecting in the peritoneal cavity? Identify the structures indicated by green arrows.

● Blue = omentum ● Yellow = mesentery ○ Ascites ○ On CT, the density of the fluid in the abdomen is indicative of its composition. ○ Soft tissue, like blood, is denser than water and thus it will appear whiter on CT imaging ○ Specifically, recent hemorrhage (acute bleed) has an attenuation value around 30-45 Hounsfield units (HU) ○ Simple ascites, with an attenuation value ranging from 0-30 HU, is primarily composed of "water-equivalent fluid" and therefore is much less dense than blood and therefore will appear darker on CT imaging. ○ Hemoperitoneum (the presence of blood within the peritoneal cavity). The green arrow indicates the loops of the small intestine (or lesions in the spleen?)

● Please identify the type of examination demonstrated in Figure 1. Describe briefly how it is performed.

(DSA) is a fluoroscopic technique in which radiopaque structures (such as bones) are eliminated digitally from the image in order to accurately visualize vasculature present within a bony or a dense soft tissue environment. Iodinated contrast agent is introduced directly into an artery via a catheter. X-ray images of the vasculature are taken following contrast administration. ○ How it's done? ■ Non-contrast image of region is taken BEFORE injecting contrast material ■ Contrast images are taken in succession while contrast material is injected. These images show the opacified vessels superimposed on the anatomy. ■ Mask image (non-contrast) is then subtracted from the contrast images pixel by pixel à result is an image with vessels only

● The local extent of the disease determines whether the patient will undergo surgery or radio-chemotherapy as a primary (first) treatment. What questions must you ask your patient to clarify whether he/she can safely undergo the imaging test you plan to request?

- - Allergy to gadolinium contrast- Renal Insufficiency (GFR < 30)- Implants: implanted electrical devices, pacemakers, metal clips, insulin pumps, etc.- Pregnancy

● Please indicate which type of examination is shown in Figure 3 (below). Please name the type of post-processing / reconstruction that was performed from the original data set. Indicate the vessels that are labeled with the letters A, B & C.

- A - Celiac Trunk - B - Superior Mesenteric A. - C - Abdominal Aorta CT angiography with maximum intensity projection (MIP)

What is a mesentery? What is THE mesentery? Which abdominal organs possess a mesentery? Which abdominal organs DO NOT possess a mesentery?

- A mesentery is a double layer of peritoneum, representing continuity of visceral and parietal peritoneum. It connects an intraperitoneal organ to the posterior abdominal wall and has a connective tissue core that functions as a passageway through which neurovasculature and lymphatics travel to the viscera from the body wall - The mesentery of the small intestine is referred to as "The Mesentery." The Mesentery is a fan-shaped fold that suspends the jejunum and ileum from the posterior body wall. Its "root" attaches to the posterior body wall a long an oblique line from the duodenojejunal junction to the ileocecal junction. - Intraperitoneal organs have a mesentery whereas retroperitoneal organs, both primary and secondary, do not.

Intraperitoneal Viscera

- Almost completely covered with visceral peritoneum - Intraperitoneal organs have literally invaginated into the closed sac because they are completely protruded into the peritoneal cavity - Thus, connected to posterior abdominal wall by a bilaminar mesentery, allowing for mobility of the organ

● Describe the extrahepatic bile passages and the pancreatic ducts.

- Bile drains from the liver via the right and left hepatic ducts, which combine to form the common hepatic duct. - The common hepatic duct is joined by the Cystic Duct to form the Common Bile Duct - The Common Bile duct joins the Major pancreatic duct to form the hepatopancreatic ampulla (Ampulla of Vater) to enter into the second portion of the duodenum at the Major duodenal papilla. - There is also a Minor pancreatic duct that drains into the duodenum more proximally than the Major Pancreatic Duct.

● Define cholecystitis, jaundice and pancreatitis.

- Cholecystitis · Inflammation of the gallbladder. There are acute and chronic forms. Both are caused by blockage of the cystic duct via different mechanisms. Gallstone formation increases the risk of cholecystitis and is a common cause of cholecystitis. - Jaundice ·hyperbilirubinemia presenting with yellowing of skin and eyes (scleral icterus) - Pancreatitis · Inflammation of the pancreas.

What is the significance of the peritoneal relationships of the rectum in terms of a breach in the rectal wall and the spread of infection?

- Given the peritoneal covering, there is a greater chance of developing peritonitis (spread of infection in the peritoneal cavity) if the breach happens in the wall happens in the superior and middle third of the rectum wall than if it happened in the inferior third of the rectum.

● Describe the innervation of the large intestine. (hindgut)

- Hindgut Region (Distal 1/3 Transvers Colon Rectum) · Sympathetic: Lumbar Splanchnic Nerves (L1-L2), Superior Mesenteric Plexus, + Periarterial plexuses following the inferior mesenteric artery · (Inferior hypogastric plexus also innervates the rectum) · Parasympathetic: Pelvic Splanchnic Nerves (S2-S4) (via Inferior Hypogastric Plexus)

What structures are related to the anterior surface of the rectum in males?

- In males, the rectum is related anteriorly to the fundus of the urinary bladder, terminal parts of the ureters, vas deferens, seminal glands, and prostate - The rectovesical septum lies between the fundus of the bladder and the ampulla of the rectum and is closely associated with the seminal glands and prostate.

● Make a diagram of the inferior mesenteric artery. What is the territory (roughly) that each of its branches supplies?

- Inferior Mesenteric Artery supplies the embryonic hindgut structures · Left Colic Artery + Branches: distal ⅓ of transverse colon (left splenic flexure anastomoses with SMA, Marginal A. of Drummond) and proximal descending colon · Sigmoid arteries: Distal end of descending colon and sigmoid colon · Superior rectal artery: rectum · Straight arteries of the colon: entirety of large intestine (straight arteries also come off the marginal artery of Drummond)

While the Latin word rectum means "straight," the human rectum is characterized by flexures in both the sagittal and coronal planes. Describe the rectum. Include its location, length, flexures, peritoneal covering, and innervation.

- Location · Rectum is the pelvic part of the digestive tract and is continuous proximally with the sigmoid colon and distal with the anal canal · Rectosigmoid Junction lies anterior to S3; this junction is where the tenia coli terminate and rectum starts · Rectum ends anteroinferior to the tip of the coccyx

● Describe the innervation of the large intestine. (midgut region)

- Midgut Region (Cecum/Appendix Proxima 2/3 Transverse Colon) · Sympathetic: T10-T12 (via Superior Mesenteric Plexus) · T10-T12 nerve fibers form synapses in the superior mesenteric plexus The superior mesenteric plexus provides sympathetic innervation to the cecum, appendix, ascending and transverse colon (near to the left colic flexure) · Parasympathetic: Vagus Nerve (via Superior Mesenteric Plexus)

Primary Retroperitoneal

- Organs that always remain external to the peritoneal cavity and posterior to the peritoneum lining the abdominal cavity - May protrude slightly into the peritoneal cavity, thus their anterior surface can be covered by parietal peritoneum

Secondary Retroperitoneal

- Originally, began as intraperitoneal viscera that fuses with the postero-lateral abdominal walls - Thus, they become immobile and only anterior surface are covered with visceral peritoneum

While the Latin word rectum means "straight," the human rectum is characterized by flexures in both the sagittal and coronal planes. Describe the rectum. Include its location, length, flexures, peritoneal covering, and innervation.

- Peritoneal Covering · First 1/3 - peritoneum covers the anterior and lateral aspects · Second 1/3 - peritoneum covers the anterior aspect · Final 1/3 - Sub peritoneal · Males the peritoneum reflects from the rectum to the posterior wall of the bladder, where it forms the floor of the rectovesical pouch · Females the peritoneum reflects from the rectum to the posterior part of the fornix of the vagina, where it forms the floor of the rectouterine pouch. · Both M/F lateral reflections of peritoneum from the superior third of the rectum form pararectal fossae which permit the rectum to distend as it fills with feces.

● Which vascular territory is shown in Figure 2? ● Please identify the vessels that are labeled A and B. ● Which organ territory is supplied by the vessels labeled C? ● Please name one clinical condition, and indication, in which it would be appropriate to perform this examination so that diagnosis and treatment can be accomplished in the same session. 5

- Superior Mesenteric Artery and branches - A - Middle Colic Artery - B - Right Colic Artery - Jejunum - Atherosclerosis and Vascular Stenosis

Describe the innervation of the rectum.

- Sympathetic · Lumbar splanchnic nerves · Hypogastric plexuses · Periarterial plexus of the inferior mesenteric and superior rectal arteries. - Parasympathetic · Pelvic splanchnic nerves (S2-S4) · L/R inferior hypogastric plexuses to the rectal plexus. - All visceral afferent fibers follow the parasympathetic fibers retrogradely to the S2-S4 spinal sensory ganglia.

Diagram the abdominal aorta. Superimpose your drawing on the illustration provided, an anterior view of the caudal portion of the vertebral column. Illustrate and label each branch. Explain the relationship of the aorta to non-bony structures of the posterior abdominal wall.

- T12 · Inferior Phrenic A. w/ Superior Suprarenal A. branching · Celiac Trunk · Middle Suprarenal A. - L1 · Superior Mesenteric A. · First Lumbar A. - L1/L2 · Renal A. w/ Inferior Suprarenal A. branching - L2 · Gonadal A. · Second Lumbar A. - L3 · Inferior Mesenteric A. · Third Lumbar A. - L4 · Fourth Lumbar A. - L4/L5 · Split of AA into Common Iliac A. · Median Sacral A. The abdominal aorta descends directly anterior to the vertebral column. It is located to the left of the IVC. It lies medial to the psoas major muscles, psoas minor muscle, and the kidneys.

What is the portal triad?

- The functional unit of the liver is called a lobule - Lobules are hexagon-shaped and have a portal triad @ every corner, which consist of: · Bile Duct · Hepatic Portal Vein · Hepatic Artery

What is the rectal ampulla?

- The rectal ampulla is the dilated terminal part of the rectum, lying directly superior to and supported by the pelvic diaphragm and anococcygeal ligament - The ampulla receives and holds an accumulating fecal mass until expelled during defecation - The ability for the ampulla to relax and accommodate fecal matter is another mechanism of fecal continence

● Discuss two techniques for liver percussion.

1. Normal percussion: a. Starting in right midclavicular line (MCL) @ 3rd intercostal space, percuss downwards towards the liver until dullness denotes the liver's upper border b. Starting at a level below the umbilicus in the right MCL, lightly percuss upward toward the liver until dullness indicates the liver's inferior border c. The measurement between the superior and inferior border of dullness is the liver span 2. Scratch test: - Place stethoscope on liver below the Xiphoid process - Scratch abdominal skin in RLQ parallel to expected liver border - Make way upward, scratching - @ liver inferior border, loudness of scratch will increase - @ liver superior border, loudness of scratch will decrease - this is liver span

Identify the structures labeled "A" - "F" in Figure 3a below. What transducer was used to obtain the image in Figure 3a?

A - IVC B - Aorta C - Portal Vein D - Superior Mesenteric A. E - Left Renal Vein F - Vertebral Body Transducer - Curvilinear Probe

Identify the structures labeled "A" - "E" in Figure 3b below. Where are the vast majority of AAA located?

A - Liver B - Abdominal Aorta C - Pancreas D - Celiac Trunk E - Superior Mesenteric A. The vast majority of Abdominal Aortic Aneurysms occur just below the kidneys (infrarenal)

● Describe the large intestine, considering its relationship to the peritoneum and the beginning and ending points of its portions— cecum and appendix, ascending colon, transverse colon, descending colon, sigmoid colon.

Ascending colon · Second part of the large intestine that passes superiorly on the right side of the abdominal cavity to the right lobe of the liver, where it turns to the left @ the right colic flexure/hepatic flexure · Peritoneum Secondarily retroperitoneal with peritoneum anteriorly and on its sides, and bound to posterior abdominal wall - Though 25% of people have a small mesentery

● For each, identify (1) the anatomic area/structure for which it is best suited, (2) the imaging modality for which it is best suited, (3) at least one clinical condition in which it should be employed, and (4) at least one clinical condition in which it should NOT be employed. BARIUM SULFATE

Barium Sulfate - (1) Preferentially used for visualization of the gastrointestinal tract. Oral or rectal delivery (NOT IV) - (2) Fluoroscopy - (3) upper GI tract ulcers, cancer, scaring, and blockages, amongst others. - (4) NEVER administer when concern for bowel perforation - can cause severe inflammation (mediastinitis, peritonitis, etc.) if leaks out

● Please name three different types of contrast agents (identified by chemical name).

Barium Sulfate Gadolinium Gastrografin

● Compare/contrast the Sonographic Murphy's examination with the Murphy's examination including clinical accuracy of each examination.

Both are used to examine cholecystitis. However, in the sonographic exam, you can see the exact position of the gallbladder, the patient holds their breath, and the sonographer is asking the patient about the pain. In normal exam, it is evaluated when the patient inhales, and relies on an involuntary reaction to the pain that stops the inspiration. Sonographic is more accurate, since exact location of gallbladder is determined. ● Murphy's sign is elicited in patients with acute cholecystitis by asking the patient to take in and hold a deep breath while palpating the right subcostal area. If pain occurs on inspiration, when the inflamed gallbladder comes into contact with the examiner's hand, Murphy's sign is positive. Sonographic is more accurate, since exact location of gallbladder is determined.

Hindgut - Boundaries - Organs - Blood - Sympathetic Nerve Supply - Parasympathetic Nerve Supply

Distal 1/3 of transverse colon to anal canal (above pectinate line) Distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum, anal canal (above pectinate line) Inferior Mesenteric Artery Preganglionic: Lumbar splanchnic nerves (Arise from lateral horns of L1-L2) Postganglionic: Inferior Mesenteric Ganglion Pelvic Splanchnic nerves (S2-S4) and enteric nervous system

Midgut - Boundaries - Organs - Blood - Sympathetic Nerve Supply - Parasympathetic Nerve Supply

Duodenum (distal to Major Papilla) to Proximal 2/3 of transverse colon Duodenum (distal to Major Papilla), jejunum, ileum, cecum, appendix, ascending colon, proximal 2/3 of transverse colon Superior Mesenteric Artery Preganglionic: Lesser and least splanchnic nerves (Arise from lateral horns of T10-T12) Postganglionic: Superior Mesenteric Ganglion Vagus nerve and enteric nervous system

Foregut - Boundaries - Organs - Blood - Sympathetic Nerve Supply - Parasympathetic Nerve Supply

Esophagus to Duodenum (proximal to Major papilla) Esophagus, Stomach, Duodenum (proximal to Major Papilla), Liver, Gallbladder, Pancreas Celiac Trunk Preganglionic: Greater splanchnic nerves (Arise from lateral horns of T5-T9/T10) Postganglionic: Celiac ganglion Vagus nerve and enteric nervous system

● For each, identify (1) the anatomic area/structure for which it is best suited, (2) the imaging modality for which it is best suited, (3) at least one clinical condition in which it should be employed, and (4) at least one clinical condition in which it should NOT be employed. GADOLINIUM

Gadolinium - (1) Gadolinium-based contrast agents are IV drugs that are best suited for the detection of focal lesions (e.g. tumor, abscess, metastasis), the examination of vessels, and for the visualization of organ perfusion. - (2) MR imaging, MR angiography, MR venography, and MR perfusion. - (3) Aneurysms, Atherosclerotic plaques, Celiac Trunk Stenosis - (4) Previous or pre-existing nephrogenic systemic fibrosis or Acutely deteriorating renal function.

● For each, identify (1) the anatomic area/structure for which it is best suited, (2) the imaging modality for which it is best suited, (3) at least one clinical condition in which it should be employed, and (4) at least one clinical condition in which it should NOT be employed. GASTROGRAFIN

Gastrografin - (1) Gastrografin is a hyperosmolar iodinated contrast medium for the radiological examination of the gastrointestinal tract. Oral delivery (NOT IV) - (2) CT - (3) Gastrografin is indicated in situations where Barium Sulfate is unsatisfactory, undesirable, or contraindicated. Specifically, Gastrografin can be used to detect leaks/perforations. - (4) NEVER administer when concern for aspiration into the lungs, as it can cause lung edema and damage

The circulatory system of the liver is unique. Describe the pattern of blood flow through the liver, including consideration of the following: terminal branches of portal vein, terminal branches of hepatic artery, liver sinusoids, central veins, hepatic veins, and inferior vena cava.

Hepatic lobules are the building blocks of liver tissue. They are hexagonal arrangements of hepatocytes with a portal triad of vessels at each of the six corners. The vessels of the portal triad include branches of the portal vein, hepatic arteries, and bile duct. - 1. Nutrient rich blood from the GI tract enters the liver from the terminal branches of the portal veins and drains into the sinusoids, which are blood filled channels between hepatocytes. - 2. Oxygenated blood enters the sinusoids via the terminal branches of the hepatic arteries - 3. This mixed blood flows to the central vein at the center of the lobule, which - - 4. drains to the hepatic veins and then finally to the - 5. inferior vena cava. Portal vein and hepatic artery → sinusoids → central vein → hepatic veins → IVC

Using the illustration provided, indicate four possible sites where portosystemic anastomoses occur; for each site, illustrate and label the vessels that are involved

In settings of portal hypertension, venous collaterals can open between the portal and systemic system. Normally, these are small and collapsed veins; but with increase portal pressure, they can engorge and become varicose. Four Possible Sites include: - 1) Umbilicus · Portal - Paraumbilical Veins (to L. Branch of Hepatic Portal) · Systemic - Epigastric Veins · Leads to physical exam finding called Caput Medusa - 2) Esophagus · Portal - Left Gastric (to Portal Vein) · Systemic - Esophageal Veins (to Azygos, to Superior Vena Cava) · Leads to esophageal varices that can rupture à upper GI bleeding - 3) Gastric · Portal - Short Gastric · Systemic - Inferior Phrenic V - 4) Rectum · Portal - Superior Rectal Vein · Systemic - Middle/Inferior Rectal Vein Leads to internal hemorrhoids above the dentate line

Describe the path taken by a thrombus in the left popliteal vein to reach the left pulmonary artery.

Left popliteal vein → Left femoral vein → L. external iliac vein → L. common iliac vein → IVC → right atrium → right ventricle → pulmonary trunk → left pulmonary artery

● Where does overflow hemorrhage go (describe the path)?

Liver: Hepatorenal Recess (Morrison's Pouch) --> Paracolic Gutter --> Rectovesical/Rectouterine pouches Spleen: ■ Overflow goes from subdiaphragmatic space, through the lesser sac, into Morrison's pouch ■ From there, right paracolic gutter rectovesical and rectouterine spaces.

Describe the visceral and parietal peritoneum, including innervation as well as folds and ligaments formed by peritoneum.

Peritoneum is a continuous serous membrane that lines the abdominopelvic cavity and invests in the viscera - Both layers consist of Mesothelium, a layer of simple squamous epithelial cells · Parietal Peritoneum · Lines the internal surface of the abdominopelvic wall · Derived from the somatic mesoderm of the lateral plate mesoderm · Served by the same blood and lymphatic vasculature and same somatic nerve supply as is the region of the wall it lines - Sensitive to pain, temperature, and laceration - Pain is well localized EXCEPT for the inferior surface of central diaphragm - Phrenic nerve (C3-C5) relays referred pain to the shoulder · Visceral Peritoneum · Invests/Covers the viscera · Derived from the splanchnic mesoderm of the lateral plate mesoderm · Served by the same blood and lymphatic vasculature and visceral nerve supply as the organ it covers - INSENSITIVE to touch and temperature à it is stimulated by stretching and chemical irritation - Pain is poorly localized: - Foregut derivative structures - Epigastric region - Midgut derivative structures - Umbilical region - Hindgut derivative structures - Pubic region

How does venous blood leave the liver?

The Proper Hepatic Artery, Portal Vein, and Common Bile Duct enter the liver via the Porta Hepatis within the Hepatoduodenal Ligament. The liver is comprised of hexagonal shaped lobules that have a portal triad @ each corner. A portal triad is comprised of branches of hepatic arteries, portal veins, and bile ducts. Hepatic arteries and portal veins drain blood into the hepatic sinusoids, flowing through Zone I (Periportal), Zone II (Intermediate), and Zone III (Centrilobular) to drain into the central vein. Blood from the central veins eventually drain into the right, left, and middle hepatic veins, which drain directly into the IVC @ the level of T8.

What is the common branching pattern of the celiac trunk? Make a diagram of the celiac trunk, and include, in addition to its three main branches, the following vessels: esophageal, short gastrics, left gastro-omental (gastro-epiploic), proper hepatic, cystic, right gastric, gastroduodenal, right gastro-omental (gastro-epiploic), and superior pancreaticoduodenal.

The celiac trunk is an artery that supplies the foregut of the gastrointestinal tract. It originates from the anterior surface of the abdominal aorta at the level of the T12-L1 intervertebral disc. The celiac trunk travels antero-inferiorly and gives off three branches: the left gastric artery, the common hepatic artery and the splenic artery. The left gastric artery is the smallest and the first branch of the celiac trunk that passes into the lesser omentum, which is the double layer of peritoneum that extends between the lesser curvature of the stomach and the liver. Within the lesser omentum, the left gastric artery passes along the lesser curvature of the stomach where it gives off esophageal branches and ultimately anastomoses with the right gastric artery to supply the superior portion of the stomach. From its origin, the common hepatic artery runs antero-inferiorly and to the right towards the liver, giving off the right gastric artery along its course. The common hepatic artery curves anteriorsuperiorly as it passes the duodenum, at which point it divides into the gastroduodenal artery and the proper hepatic artery. The splenic artery is the largest branch of the celiac trunk. From its origin, it travels antero-inferiorly and to the left, towards the pancreas. Along this course, the splenic artery gives off many branches including the left gastro-omental, the short gastric, the posterior gastric, the dorsal pancreatic, and the greater pancreatic arteries as well as the artery to the tail of the pancreas. The splenic artery then passes posterior to the superior portion of the pancreas, to the splenic hilum. Within the spleen, the splenic artery ultimately divides into many smaller splenic branches.

● Which vascular territory is shown in this image? Please name the major branches that are labeled A through C. Which major abdominal vessel do these ultimately originate from? Why is that major abdominal vessel not seen in the image?

The common hepatic artery, a branch of the celiac trunk, and its major branches are shown here. ○ A = left hepatic artery ○ B = right hepatic artery ○ C = gastroduodenal artery These vessels ultimately arise from the abdominal aorta. The abdominal aorta is not seen in this image since the contrast agent was delivered directly to the celiac trunk, from which it coursed through the three major branches, away from the abdominal aorta.

Describe the location and significance of the marginal artery of Drummond?

The marginal artery of Drummond is an artery that supplies the proximal descending colon at the splenic flexure. It is an arterial arcade formed by anastomoses between the superior and inferior mesenteric arteries, representing dual blood supply that can protects against ischemia, especially in cases of vessel occlusion. However, the marginal artery of Drummond is very small and supplied by distal branches of the SMA and IMA, meaning in cases of systemic hypoperfusion (heart failure, etc.), this region is susceptible to ischemia as it is least likely to receive sufficient blood. Due to its dual blood supply, this area is considered a "Watershed" area.

Illustrate the common branching pattern of the superior mesenteric artery. Be sure to include the following vessels: inferior pancreaticoduodenal, right colic, middle colic, intestinal branches, and ileocolic. Also illustrate the vasa recta and the arterial arcades of the jejunum and of the ileum. Describe the marginal artery (of Drummond).

The marginal artery of Drummond is an artery that supplies the proximal descending colon at the splenic flexure. It is an arterial arcade formed by anastomoses between the superior and inferior mesenteric arteries, representing dual blood supply which protects against ischemia, especially in cases of vessel occlusion. For this reason, it is called a "Watershed" area. However, the marginal artery of Drummond is very small and represents the most distal aspects of the SMA and IMA, and thus is susceptible to under perfusion.

Describe the large intestine, considering its relationship to the peritoneum and the beginning and ending points of its portions— cecum and appendix, ascending colon, transverse colon, descending colon, sigmoid colon.

Transverse colon · Third, longest, and most mobile part of the large intestine · It crosses the abdomen from the right colic/hepatic flexure to the left colic/splenic flexure, where it turns inferiorly to become the descending colon · Peritoneum Intraperitoneal, with a mesentery called the transverse mesocolon - The root of the transverse mesocolon lies along the inferior border of the pancreas and is continuous with the parietal peritoneum posteriorly

● What is the Cystohepatic Triangle (of Calot)?

Triangular space formed by the cystic duct inferiorly, common hepatic duct medially, and the inferior surface of the liver superiorly.

● Please indicate the most appropriate imaging technique to demonstrate cholecystitis.

US

Digital Subtraction Angiography Is contrast agent needed for this examination? If so, what type of contrast agent is used? Please indicate if this is an invasive or noninvasive procedure.

Yes, an iodinated contrast agent is needed for this examination. It is administered directly into the artery via a catheter, which makes this an invasive procedure.

● Please identify four imaging modalities that you can use to visualize and evaluate vessels. ● Give an example of the use of each technique in the abdomen or pelvis.

a. 1) CT angiography is considered to be the gold standard imaging modality for detection of the proximal celiac stenosis with classic hooking configuration b. 2) MR angiography (MRA) can be used to detect an abdominal aortic aneurysm. c. 3) Intravascular ultrasound can be used to detect abdominal aortic aneurysm assessment and for endovascular graft delivery 4) DSA is considered the gold standard investigation for renal artery stenosis

● Identify the three clinically important sites where gallstones can lodge in the extrahepatic biliary passageways.

· 1) Ampulla of Vater · 2) Common bile duct · 3) Cystic duct.

● Please enumerate three different imaging modalities that are well suited not only to imaging the liver in general, but also for purposes of identifying metastases. For each of these 3 modalities, please state whether you would perform the examination with or without contrast.

· 1) MRI with contrast (gadolinium) · 2) CT with iodinated contrast · 3) Ultrasound w/o contrast

While the Latin word rectum means "straight," the human rectum is characterized by flexures in both the sagittal and coronal planes. Describe the rectum. Include its location, length, flexures, peritoneal covering, and innervation.

· 12-15 cm long

● What type of examination is shown in Figure 4? ● Is this examination performed with intravenous contrast? How can you determine this? ● In which of these two vessels is a filter placed to prevent pulmonary embolism? What is the high-density structure in the other vessel? ● Are such filters placed above or below the level of the renal vasculature? Why? ● In this same image you see also a hypodense structure in the liver (blue arrow). Is this a normal anatomic structure or a pathology? What could you do to better characterize this structure? (Please name two possibilities.)

· Abdominal Coronal CT Scan · NO because the vessels are hypodense (dark). If contrast were used, vascular structures would be hyperdense (bright) · A - IVC · B - Abdominal Aorta · The filter is placed in the IVC (vessel A) to prevent pulmonary embolism The other high-density structure represents calcified atherosclerotic plaques · In nearly all cases, the filter should be positioned within the deployment sheath in the desired location (which is typically immediately below the inflow of renal veins). · This minimizes the risk of filtered occlusive thrombus slowing/occluding renal vein outflow · The inflow of blood from the renal veins will tend to minimize clot formation cranial to an appropriately placed infrarenal IVC filter. - Pathological · 1) Color Doppler to visualize blood flow · 2) CT Angiogram w/ iodinated contrast

● Describe the large intestine, considering its relationship to the peritoneum and the beginning and ending points of its portions— cecum and appendix, ascending colon, transverse colon, descending colon, sigmoid colon.

· Appendix · Blind intestinal diverticulum off of the posteromedial aspect of the cecum, inferior to the ileocecal junction · Contains masses of lymphoid tissue and can become inflamed · Peritoneum Short triangular mesentery called the mesoappendix

Ascending part of duodenum

· Ascending Part · Begins @ left of L3 vertebra and rises superiorly as far as superior border of L2 · Curves anteriorly to join the jejunum at the duodenojejunal flexure, which is supported by the suspensory ligament of the duodenum (aka ligament of Treitz), which attaches the diaphragm to the duodenum

● Describe the large intestine, considering its relationship to the peritoneum and the beginning and ending points of its portions— cecum and appendix, ascending colon, transverse colon, descending colon, sigmoid colon.

· Cecum · First part of the large intestine and is continuous with the ascending colon · Is a blind intestinal pouch that exists in the iliac fossa in the RLQ and inferior to the ileocecal junction · Peritoneum Almost entirely enveloped by peritoneum, but it has no mesentery - However, usually bound to the lateral abdominal wall by one or more cecal folds of peritoneum

● What is the location of the pancreas (peritoneal? retroperitoneal? vertebral levels?).

○ Head, Uncinate process, neck, and body are considered secondarily retroperitoneal ○ Tail is considered intraperitoneal ○ Pancreas overlies and traverses the L1 and L2 vertebrae on the posterior abdominal wall ○ Posterior to the stomach, between the spleen and duodenum

Describe the large intestine, considering its relationship to the peritoneum and the beginning and ending points of its portions— cecum and appendix, ascending colon, transverse colon, descending colon, sigmoid colon.

· Descending Colon · Fourth part of large intestine between the left colic flexure and left iliac fossa, where it is continuous with the sigmoid colon · Peritoneum Secondarily retroperitoneal with peritoneum anteriorly and on its sides, and bound to posterior abdominal wall - Though 33% of people have a small mesentery

Descending part of duodenum

· Descending Part · Longer, approximately 7-10 cm., descending along right sides of the L1-L3 vertebrae · Curves around the pancreas; contains the major duodenal papilla where the hepatopancreatic ampulla (formed via fusion of common bile duct and major pancreatic duct) opens

● Briefly describe the jejunum and ileum.

· Distal parts of the small intestine both are intraperitoneal and attached to the posterior abdominal wall by The Mesentery · Both supplied by the Superior Mesenteric Artery (SMA), and drained by the SMV · Both are specialized for absorption · Jejunum plays a large role in nutrient absorption · Ileum absorbs what was not absorbed by the Jejunum and specializes in Vit. B12 and bile acid recycling - The jejunum begins at the duodenojejunal flexure (There is no clear external demarcation between the jejunum and ileum - although the two parts are macroscopically different) - The ileum ends at the ileocecal junction - Together, the jejunum and ileum are 6-7 m long, the jejunum constituting approximately two fifths and the ileum approximately three fifths of the intraperitoneal section of the small intestine.

What structures are related to the anterior surface of the rectum in females?

· In females, the rectum is related anteriorly to the vagina and is separated from the posterior part of the fornix and the cervix by the rectouterine pouch · Inferior to this pouch, the weak rectovaginal septum separates the superior half of the posterior wall of the vagina from the rectum.

● Indicate the two methods that best determine a) the local stage of disease and b) the nodal and distant metastatic stage of disease (one for each). ● Give at least two advantages and one disadvantage for each imaging method you have proposed to perform the local staging.

· Local Stage of Disease MRI or Ultrasound · Nodal/Distant Metastatic Stage CT or PET Scan ○ MRI ■ Advantages 1) No ionizing radiation exposure, 2) Excellent anatomic detail ■ Disadvantages 1) Expensive · Ultrasound · Advantages 1) Cheap, 2) No ionizing radiation exposure · Disadvantage 1) Less anatomic detail

● Please name the two main imaging examinations with which you can look for gallstones in the common bile duct. For each examination, briefly describe the technique, including whether it is invasive or non-invasive, whether it uses contrast agents, and whether it allows for treatment in the same imaging session.

· Magnetic Resonance Cholangiopancreaticography (MRCP) · MRI of the abdomen designed to characterize pancreatico-biliary disorders; relies on signal given by fluid in heavily weighted T2 imaging · Non-invasive · No contrast · Only is anatomic; does not allow for treatment · Endoscopic Retrograde Cholangiopancreaticography (ERCP) · Endoscope is advanced into the duodenum, papillae are cannulated, contrast is injected · Invasive · Contrast required · Intervention possible with instruments under fluoroscopy guidance

● Your patient tells you that he has had total hip replacements. Does this affect your decision of ordering the planned examination to determine the patient's local stage of his rectal cancer? Describe what you can do to clarify the situation.

· Metal hip replacement devices may or may not be compatible with MRI. Some devices have an MRI conditional that allow for patients to undergo MRI. · Would need to check the specifications of the patient's implants in order to assess if MRI is the best option · If not compatible, use ultrasound instead

● Name and describe three features that distinguish the large intestine from the small intestine

· Omental appendices: small, fatty, omentum-like projections. · Teniae coli: 3 distinct thickened bands of smooth muscle representing most of the longitudinal coat · Haustra: sacculation of the wall of the colon created by the tonic, segmental contraction of the tenia coli · A much greater caliber (internal diameter).

While the Latin word rectum means "straight," the human rectum is characterized by flexures in both the sagittal and coronal planes. Describe the rectum. Include its location, length, flexures, peritoneal covering, and innervation.

· Sacral Flexure of Rectum - curve generated by rectum following curve of sacrum · Anorectal Flexure of the anal canal - sharp, posteroinferior 80-degree angle that occurs as the gut perforates the pelvic diaphragm (levator ani) · Very important mechanism in keeping fecal continence via tonic contraction of the puborectalis · 3 Sharp Lateral Flexures of the Rectum superior and inferior on left side, and intermediate on right · Flexures that are formed in relation to the internal transverse rectal folds (2 on left, 1 on right)

Describe the large intestine, considering its relationship to the peritoneum and the beginning and ending points of its portions— cecum and appendix, ascending colon, transverse colon, descending colon, sigmoid colon.

· Sigmoid Colon · Sigmoid colon is characterized by its S-shaped loop that links the descending colon and rectum - It extends from the iliac fossa to S3 vertebra, where it joins the rectum - Rectosigmoid junction is delineated by the termincation of the teniae coli · Peritoneum Intraperitoneal, with a mesentery called the Sigmoid Mesocolon that allows for great sigmoid colon movement

● Please describe the functions of the major regions of the small and large bowel.

· Small Bowel · Duodenum: where absorption begins; site where pancreatic enzymes and bile enter GI tract via hepatopancreatic ampulla, which leads to further chyme breakdown and absorption of lipids; also neutralizes stomach acid before chyme enters jejunum · Jejunum: absorb sugars, amino acids, and fatty acids · Ileum: absorbs any remaining nutrients not absorbed by duodenum or jejunum (particularly vitamin B12) as well as bile acids that are recycled · Large Bowel · Main regions: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal · Primary functions: absorb water and electrolytes, absorb vitamins, and form and propel feces through the GI tract for excretion

· Superior Part of duodenum

· Superior Part · Short, approximately 5 cm., lying anterolateral to L1 vertebra · Proximal 2 cm of the superior part of the duodenum has a mesentery and is mobile, called the Ampulla (intraperitoneal) - Hepatoduodenal ligament (of the lesser omentum) attached superiorly - Greater omentum attached inferiorly · Distal 3 cm of superior part of duodenum does NOT have a mesentery and is immobile (retroperitoneal) Has peritoneum covering anterior aspect, but not posterior

Name retroperitoneal organs

· Suprarenal/Adrenal Glands · Aorta · IVC · Duodenum (2nd-4th part) (Secondarily Retroperitoneal) · Pancreas (except tail) (Secondarily Retroperitoneal) · Ureters · Colon (Ascending and Descending) (Secondarily Retroperitoneal) · Kidneys · Esophagus · Rectum

Inferior (horizontal part) of duodenum

· Transverses left over the L3 vertebra, IVC, and aorta · SMA and SMV cross OVER it

● What type of examination is pictured in Figure 9 below? ● What organ(s) or anatomical structure(s) do you see in this image? ● Identify the structures labeled with the numerals 1, 2, and 3. ● What phenomenon seen here is labeled with the 4's? ● If the structure labeled 2 becomes inflamed, there are specific signs in this imaging test which indicate inflammation. Please name three major signs.

· Ultrasound of Gall bladder ○ Gall Bladder, Cystic Duct, Gall Stones, Liver ○ 1 - Liver ○ 2 - Gall Bladder ○ 3 - Gall Stones ○ Posterior Acoustic Shadowing ○ Dilated gallbladder (>4 cm axial diameter) ○ Wall thickening (>3 mm) ○ Pericholecystic fluid ○ Gallstones Sonographic Murphy's Sign

● Please refer to Figure 9a below to answer the following questions. ○ Identify the structures labeled "A" - "F" in Figure 9a below. ● What laboratory abnormalities would be expected with a biliary obstruction at A? ● What laboratory abnormalities would be expected with a biliary obstruction at C? ● At which level(s) shown (refer to letters in image) would biliary obstruction result in a patient clinically having jaundice? ○ Please provide one exception to this rule.

■ A: gallbladder ■ B: cystic duct ■ C: common bile duct ■ D: main pancreatic duct ■ E: duodenum (maybe plicae circulares) ■ F: major duodenal papilla Cholelithiasis in Gall Bladder - typically normal ■ If Biliary Colic occurs (sudden pain if gallstone tries to pass into B, the cystic duct), then labs may change Choledocholithiasis - Stone in CBD ○ Elevated urine conjugated bilirubin (aka direct bilirubin) ○ ↑ Alk Phos, ↑GGT, ↑ AST/ALT, ↑ direct bilirubin ■ Obstruction @ C and F ■ Exception if the stone is not large enough to obstruct total flow of the duct, jaundice may not occur

Please identify four imaging modalities that you can use to visualize and evaluate vessels. For each of them, indicate if you would need to use contrast agents.

○ 1) CT angiography - iodinated contrast media ○ 2) Contrast-enhanced MRA requires the administration of gadolinium contrast media ○ 3) Intravascular Ultrasound does not require contrast agents ○ 4) DSA - iodinated

● Identify the structures labeled "A" - "E" in Figure 1a below. What transducer was used to obtain the image in Figure 1a?

○ A 5-2 MHz curvilinear transducer was used to obtain the transverse ultrasound image in Figure 1a. ○ A = common hepatic artery ○ B = splenic artery ○ C = abdominal aorta ○ D = inferior vena cava ○ E = celiac trunk

Please refer to Figure 7a below to answer the following questions. ● Identify the structures labeled "A" - "E" in Figure 7a below. ● Is the structure labeled as D, intraperitoneal or retroperitoneal? ● Can ultrasound be used to diagnose the type of fluid present?

○ A = liver ○ B = right kidney ○ C = free fluid in Morrison's Pouch ○ D = Renal Capsule or Garota's Fascia ○ E = diaphragm ○ Intraperitoneal ○ US can detect particulate matter, but it cannot be used to definitively diagnose the type of fluid.

● What classification system is used to describe the location of an abnormality in the liver? ● What major landmarks are used to determine the segments of the liver? How many liver segments are there?

○ Couinaud Segments 8 segments total ○ Portal vein bifurcation divides upper and lower (cranial v caudal) segments ○ Hepatic veins divide the vertical borders of the segments in coronal plan ○ Exceptions: ■ Caudate lobe (I) is separate ■ Segment IV combines upper and lower

● What is the clinical role/utility of the FAST exam? ● Name the four sonographic windows of the FAST exam.

○ FAST - Focused Assessment with Sonography for Trauma ■ Use ultrasound to identify free fluid in intraperitoneal or pericardial spaces ■ FAST exam is indicated for patients who have sustained blunt/penetrating chest or abdominal trauma ■ It is usually conducted in the emergency setting to quickly screen for internal ruptures or trauma resulting in malperfusion of fluid or bleeding. ■ Cardiac (most often subxiphoid) ■ Right Upper Quadrant ■ Left Upper Quadrant ■ Pelvic

● Describe the physical examination techniques used to identify ascites?

○ Fluid wave test ■ Patients lie supine, place palm of one of your hands on right flank and have patient firmly press the ulnar edges of hand on midline of abdomen to prevent wave transmission through fat ■ Firmly tap left flank with your free hand ■ If ascites present, tap will transmit an impulse through the fluid, which you will feel with your palm on right flank ○ Shifting dullness test ■ Patient lies supine, percuss from mid-abdomen to flank area and note changes from tympany to dullness (tympany over air-filled bowel, dullness over areas of fluid) ■ Have patient lie facing you and percuss from upper side of abdomen downward. - When ascites is present, the area of dullness will shift to the dependent site. The area of tympany will shift toward the top.

● By what means was the image shown below (Figure 8) obtained? ● Is a common bile duct stone seen? If so, please identify it with an arrow. ● Please name the anatomic structures labeled A through E

○ Magnetic Resonance Cholangiopancreaticography (MRCP) ○ YES Letter "B" points to a Common Bile Duct Stone ○ A - Gall Bladder ○ B - Gall stone in Common Bile Duct ○ C - Left Hepatic Duct ○ D - duodenum ○ E - Stomach

● Please indicate the most appropriate imaging technique to demonstrate pancreatitis.

○ Magnetic Resonance Cholangiopancreaticography (MRCP) ○ Or Contrast-enhanced CT

● Describe the Sonographic Murphy's examination.

○ Sonographic Murphy sign is defined as maximal abdominal tenderness from pressure of the ultrasound probe over the visualized gallbladder. It is indicative of cholecystitis.

● Does this patient have splenomegaly? ● List three causes of splenomegaly. ● Describe the technique of splenic percussion. ● Is dullness to percussion over Traube's space during inspiration consistent with a normal spleen size (YES or No)?

○ Splenomegaly is diagnosed when the largest dimension is greater than 13cm. In this image, the spleen appears to be 18cm in length, meaning this patient has splenomegaly. ○ Cirrhosis - Budd Chiari Syndrome - Viral Hepatitis ○ Portal Vein Thrombosis ○ Trauma ○ Hematologic malignancies such as leukemia's and lymphomas ○ Infectious diseases such as HIV and malaria ○ Castell's method: - Find Castell's Point, the intersection between the most inferior intercostal space and the left anterior axillary line - This is usually tympanic. Ask patient to breath deeply. - If remains tympanic on inspiration: Splenic Percussion Sign negative: splenomegaly less likely. - If shift from tympanic to dullness: Splenic Percussion Sign positive: splenomegaly more likely. How this works? --> The spleen will migrate caudally upon inspiration due to pressure from the diaphragm, and dullness indicates that the lower border of the spleen could have moved past Castell's point, indicating splenomegaly. NO

● How are the pancreas and duodenum (anatomically) related?

○ The duodenum forms a C-shape around the head of the pancreas. The pancreas empties its contents into the duodenum through the major and minor pancreatic ducts and into the major and minor duodenal papilla.

What is the lesser omentum? What is the greater omentum? What is the falciform ligament?

● Omentum ○ An omentum is a double-layered extension or fold of peritoneum that passes from the stomach and proximal part of the duodenum to adjacent organs in the abdominal cavity ● Lesser Omentum ○ The lesser omentum, which consists of two layers of visceral peritoneum, extends between the lesser curvature of the stomach and the proximal duodenum and the liver. ○ Formed by the: ■ Hepatogastric Ligament, ■ Hepatoduodenal Ligament (contains the portal triad) ● Greater Omentum ○ The greater omentum is a prominent, four-layered peritoneal fold that hangs down like an apron from the greater curvature of the stomach and the proximal part of the duodenum ○ Formed by: ■ Gastrocolic Ligament ■ Gastrosplenic Ligament ■ Gastrophrenic Ligament ● Falciform Ligament ○ The falciform ligament is a double fold of peritoneum that attaches the liver to the anterior abdominal wall. This ligament is is 'sickle-shaped' and it separates the liver into the left medial lobe and the right lateral lobe. Between its two peritoneal layers, the falciform ligament contains the round ligament and the paraumbilical veins.