Page 22 Flashcards
1
Q
Most dependent portion of the abdominal cavity in a supine px
A
Morison pouch (right hepatorenal fossa/ right posterior subhepatic space)
2
Q
Most dependent portion of the peritoneal cavity in the upright patient
A
Pelvis
2
Q
The lesser sac communicates with the greater sac through?
A
Foramen of Winslow
3
Q
Most dependent portion of the peritoneal cavity
A
Cul-de-sac
4
Q
Left subphrenic space and left subhepatic space communicate freely but separated from
right subphrenic space by?
A
Falciform ligament
4
Q
Right subphrenic and subhepatic spaces communicate freely with the pelvic peritoneal cavity via?
A
Right paracolic gutter
5
Q
Left subphrenic/subhepatic space separated from left paracolic gutter by?
A
Phrenicocolic ligament
6
Q
This is the remnant of the obliterated umbilical VEIN
A
Ligamentum teres
6
Q
Xray dx of ascites requires how many __ml of fluid to be seen?
A
500ml
7
Q
Xray technique/position most sensitive for free air
A
Upright chest xray
7
Q
Pseudomyxoma peritonei may result from?
A
1) Rupture of appendiceal mucocele 2) intraperitoneal spread of of benign or mucinous cysts of the ovary 3) mucinous adeno CA of the colon/rectum
8
Q
Popcorn calcification
A
Uterine leiyomyoma
8
Q
What are the signs of pneumoperitoneum on supine radiograph?
A
1) Rigler sign - gas on both sides of bowel wall; 2) gas outlining the falciform ligament, 3) football sign - gas outlining peritoneal cavity, 4) triangual or linear localized extraluminal gas in the RUQ
8
Q
Post-operative pneumoperitoneum resolves in how many days?
A
3-4 days
9
Q
Rice-grain calcifications
A
Cysticercosis in muscles
9
Q
Tooth-like/bone calcification
A
Benign cystic teratoma
10
Q
Post-operative ileus resolves in how many days?
A
4-7 days
10
Q
Dilated bowels
A
small bowel >2.5-3 days; colon >5 cm; cecum >8 cm
10
Q
Air-fluid levels
A
normal = stomach; often = small bowel; NEVER = colon distal to hepatic flexure
11
Q
How many hours before radiograph can confirm the presence of bowel obstruction?
A
6-12 hrs
11
Q
What is the most striking finding of toxic megacolon?
A
dilatation of transverse colon up to 15 cm
12
Q
What is the imaging method of choic to confirm small bowel obstruction?
A
CT (small bowel feces sign)
12
Q
What is the most specific sign for strangulation obstruction?
A
lack of enhancement of the bowel wall
12
Q
Low-density nodal metastases are commonly seen with
A
Nonseminomatous testicular ca, TB, and lymphoma (occasionally)
13
Upper limits of normal lymph node size
6mm = retrocrural and porta hepatis; 8mm = gastrohepatic ligament; 10mm = retroperitoneal, celiac and SMA, pancreaticoduodenal, perisplenic, and mesenteric; 15mm = pelvic
13
What is the hallmark of retroperitoneal fibrosis?
smooth extrinsic narrowing of one or both ureters in the region of L4-L5
13
Portal venous flow may be altered by?
1) portal blockade by tumor or thrombus, 2) extrinsic compression by ribs or diaphragmatic slips, or tumors on the liver capsule, 3) third inflow from systemic veins - pericholecystic, parabiliary, and epigastric-paraumbilical venous systems
14
How to differentiate lymphoma from retroperitoneal fibrosis?
Lymphoma extends behind the vessels and displaces them anteriorly, retroperitoneal fibrosis does not
14
Hepatic arterial flow may be increased by?
1) focal hypervascular lesion, 2) inflammation of adjacent organs (cholecystitis, pancreatitis), 3) aberrant hepatic arterial supply
15
What is the primary role of imaging patients with chronic hepatitis?
to detect HCC
16
Diffentiation b/w regenerative and dysplastic nodules
regenerative (no atypia)/low grade nodules (minimal atypia)- portal venous supply = NO arterial enhancement; High grade dysplastic (moderate atypia)- hepatic artery supply = SHOW arterial enhancement, PREMALIGNANT, secrete AFP
17
How to differentiate HCC from other arterially enhancing lesions (pseudolesion, THAD)?
On delayed imaging, HCC becomes hypointense to surrounding liver, whereas other non-specific lesions are isointense
17
How to differentiate acute from chronic fibrosis of the liver?
On T1 = hypointense to liver (both); T2 = HIGH due to increase fluid content (acute), T2 LOW (Chronic)
17
Differentiation b/w dysplastic nodule and small HCC
Dysplastic nodules are almost NEVER hyperintense on T2W compared with HCC
18
What is the hepatic parenchymal attenuation to suggest hemochromatosis?
> 72 HU
18
Causes of T1 HYPERintensity in focal liver lesions
fat deposits, blood, pretein, copper, melanin, contrast, ghosting artifact, iron, and edema
18
How to differentiate portal venous gas vs pneumobilia?
Gas in portal vein extending to liver capsule, while in pneumobilia gas is more central and does not extend to 2 cm of the the liver capsule
19
Long standing hemochromatosis patients are at risk for?
cirrhosis, HCC, and colorectal ca
19
Where can you find pseudocirrhosis?
HHT
20
Causes of T2 HYPOintensity in focal liver lesions
fibrous capsule (HCC, hep adenoma, FNH); fibrous central scar (FNH, fibrolamellar hepatocellular ca)
21
Hallmark finding in HCC
heterogeneous arterial enhancement with rapis wash out of contrast on venous phase; hypointense on delayed phase
22
What are the fat containing lesions in the liver?
Hepatic adenoma, HCC, focal fatty deposition, lipoma, teratoma, liposarcoma, postop packing material (omentum), and foacl intrahepatic extramedullary hematopoiesis
22
How to differentiate HCC from regenerative or dysplastic nodules?
Hypointense on delayed postcontrast phase a feature of HCC, not seen with regenerative or dysplastic nodules on MR
22
What is Peliosis hepatis?
rare, assoc with chronic wasting from cancer or TB; cystic dilatation of hepatic sinusoids and multiple small blood-filled spaces
23
How to differentiate amebic from pyogenic abscess?
indistinguishable by imaging; diff is made by history, serology, or aspiration; amebic = most RIGHT lobe with elevation of R hemidiaphragm
24
What is the normal size of intrahepatic ducts?
does not exceed 40% of diameter of adjacent portal vein, or 2mm in central liver, or 1.8mm in peripheral liver
25
What is the normal size of extrahepatic ducts?
not exceed 6-7mm in internal diameter
26
Difference between benign and malignant bile duct strictures
gradual tapering of dilated common duct and minimal wall enhancmenet= BENIGN; abrupt termination of dilated common duct and hyperenhancement on PV phase = MALIGNANT
27
MRCP may still miss stones of what size?
smaller than 3 cm because they are lost within high signal fluid
28
What are the diseases that may complicate/cause Cholangiocarcinoma?
Primary sclerosing cholangitis, recurrent pyogenic cholangitis (oriental cholangiohepatitis), Caroli disease
29
What is the size of the gallbladder when contracted and enlarged?
contracted = <2 cm; enlarged (hydropic) = >5 cm
30
Adenomyomatosis has no malignant potential. T or F?
TRUE
30
Adenomatous polyps are potentially premalignant. T or F?
TRUE
30
Size of polyp that needs to be resected because of risk of cancer
>10 mm
31
Normal size of pancreas
3 x 2.5 x 2 cm (head, body, tail)
32
Normal pancreatic duct size
3-4 mm diameter in the head and tapers toward the tail
32
What are the signs of resectability of panc ca?
isolated mass, no extrapancreatic dse, no encasement of celiac, SMA
33
What are the signs of potential resectability of panc ca?
no involvement of celiac, SMA, regional nodes may be involved, limited peripanc extention
33
What are the signs of unresectability of panc ca?
encasement of celiac/SMA, occlusion of SMV/portal vein, distant mets
34
How do you define encasement of vessel?
Tumor abutting more than 180deg, focal narrowing, or occlusion
35
Highest malignant potential among the functioning NET?
80% glucagonoma, 60% gastrinoma, 10% insulinoma
35
How do you differentiate functioning from non-functioning NET?
Non-functioning usually mas pangit, 80% malignant, larger in size than the functioning NET
36
What are the 3 imaging appearances of serous cystadenoma?
microcystic (MC), macrocystic, innumerable tiny cysts that appear solid
36
What type of IPMN carries higher risk of carcinoma?
Main duct IPMN 65%, branch duct IPMN 15%
37
What is a highly diagnostic feature of serous cystadenoma?
central stellate scar that may calcify
37
How to differentiate pseudocyst from serous cystadenoma?
septations and lobulated contours are more often associated with serous cystadenoma; pseudocysts = usually shows involution on serial imaging
38
Normal size
12 x 7 x 3-4 cm (length, width, thickness)
38
How do you differentiate mass from chronic panc vs adenoca?
Chronic panc - beaded dilatation of panc duct, adenoca - smooth dilatation of panc duc
39
Cysts found in Cystic fibrosis are true cysts. T or F?
TRUE (pancreatic cystosis - macrocysts of varying size developing from functional remnants of pancreatic ducts
40
Largest lymphoid organ?
spleen
41
Cysts found in posttraumatic spleen are true cysts. T or F?
FALSE; usually calcify
42
Cysts in epidermoid cysts of the spleen are true cysts. T or F?
TRUE
42
How do you define splenomegaly?
>14cm, lower edge lower than liver or kidney, extends ventral to ant axillary line
43
What are the 4 major categories of causes of splenomegaly?
Congestive, myeloproliferative, infectious, infiltrative
43
Early sign of dysmotility or esophagitis
(transverse folds of the esophageal mucosa from contraction of longitudinal fibersFeline esophagus)
44
normal thickness of the wall of the distended esophagus
not >3mm
44
A radiographic marker of GEJ seen on single-contrast barium study
B ring
45
A radiographic marker of GEJ seen on double-contrast barium study
Z line
46
How to differentiate primary and secondary achalasia?
Primary = short length of narrowed segment; secondary (cancer) = longer segment >3.5cm
46
Most sensitve means of diagnosing abnormal GERD in ambulatory patient
Monitoring of esophageal pH for 24hrs
47
Most patients with hiatus hernia do not have GERD, while most GERD patients have
TRUE
48
What is the upper limit of normal hiatal width?
15mm
49
Difference b/w Zenker and Killiam-Jamieson diverticula
(Both upper esophagus) Zenker = hypopharynx, posterior midline, small neck; Killian-Jamieson = below cricopharyngeus, lateral (left), wide neck
50
Difference b/w pulsion and traction diverticula
(both midesophagus) Pulsion = mucosa and submucosa herniate thru muscularis; Traction = contain all esophageal layers
50
EPiphrenic diverticula?
lower esophagus, usually on the right side
51
Least common portion of the GIT to be involved by TB
esophagus
51
Characterictic radiographic appearance of Barrett esophagus?
high (midesophageal) stricture or deep ulcer in px with GERD
52
Causes of upper and middle esophageal strictures?
Barrett esopahgus, mediastinal radiation, caustic ingestion, and skin diseases (pemphigoid, erythema multiforme, epidermolysis bullosa)
52
Causes of distal esophagitis?
GERD, scleroderma, prolonged NGT
53
Difference b/w pharyngeal and esophageal webs?
Pharyngeal = anterior wall of hypoharynx; Esophageal = anywhere MC in cervical esophagus just distal to cricopharyngeus imppression
53
Difference b/w benign and malignant strictures?
Benign = smooth tapering concentric narrowing; Malignant = abrupt, asymmetri, eccentri narrowing with irregular nodular mucosa
53
Hallmark finding of esophagitis
Ulcers
53
Difference b/w Boerhaave syndrome and Mallory-Weiss tear?
Boerhaave = full-thickness tear in left posterior wall near left crus of diaphragm; MWT = only mucosa torn, longitudinal oriented in distal esophagus
53
4 common morphologic growth patterns of gastric carcinoma
1. polypoid masses
2. ulcerative masses
3. focal infiltrating tumors (plaque-like lesion w/ central ulcer)
4. diffuse infiltrative (scirrhous ca)
53
Normal gastric wall thickness when distended
antrum = 5-7mm, body = 2-3 mm (duodenum <3mm)
53
Major cause of chronic gastritis, duodenitis, benign gastric and duodenal ulcers, gastric
H. pylori
54
4 morphologic patterns of gastric lymphoma
1. polypoid solitary mass
2. ulcerative mass
3. multiple submucosal nodules
4. diffuse infiltration
54
CT findings differentiating gastric LYMPHOMA from carcinoma
1. marked wall thickening (>3 cm)
2. involvement of additional areas of GI tract
3. no invasion of perigastric fat
4. no luminal narrowing and obstruction despite extensive involvement
5. widespread and bulkier adenopathy
55
Hallmarks of gastritis
1. thickened folds
2. superficial mucosal ulcerations (erosions)
56
Hallmark of benign ulcers
mucosa that is intact to the very edge of an undermining ulcer crater; depth of ulcer greater than width
56
Gastritis with sparing of the antrum
1. Atrophic gastritis
2. Menetrier disease
57
Most of gastric ulcers are benign. T or F?
TRUE
57
Evidence of malignant ulcers
irregular tumor mass or infiltration of surrounding mucosa; shallow ulcer with width greater than depth
58
Duodenal tumors
bulb = 90% benign, 2nd and 3rd portion = 50% benign/malignant, 4th portion = most are malignant
59
Brunner glang hyperplasia vs hamartoma
Hamartoma = >5 mm
59
Barium studies should be avoided in patients with acute stages of UGI hemorrhage. T or F?
TRUE
60
Location of Chron disease of duodenum
1st and 2nd portions
60
Disease/syndrome that have Increased risk for small bowel carcinoma
Adult celiac disease, Crohn dse, and Peutz-jeghers syndrome
61
Differentials for annular constricting lesions of the small bowel
small bowel adenocarcinoma, annular mets, intraperitoneal adhesions, malignant GIST, lymphoma (rare)
62
Differentiating finding in lymphoma in comparison w/ GIST and adenocarcinoma?
lymphoma enhances little
63
Hallmark of mechanical bowel obstruction
point of transition b/w dilated and nondilated bowel
64
Ddx of annular constricting lesions of the small bowel
adenoca, annular mets, intraperitoneal adhesions, malignant GISTs, lymphoma (rare)
65
Differentiate exophytic lymphoma vs GIST and adenoca
exophytic lymphoma - enhances little, if any; GIST and adenoca - enhance prominently
66
Differentiate carcinoid tumors and small bowel adenoca vs melanoma in terms of their mesenteric metastases
carcinoid and SI adenoca - prominent desmoplastic reaction in the mesentery; melanoma - no mesenteric retraction
67
Patient condition that have increased risk for colon ca
ulcerative colitis, crohn disease, Peutz-Jeghers syndrome, familial adenomatous polyposis
67
Filling defects seen on barium enema include the ff considerations
polyps, tumor, plaques, air bubbles, feces, mucus, or foreign objects
68
Syndrome/diseases associated with Hamartomatous polyposis syndrome
Peutz-Jeghers syndrome, Cowden syndrome, Chronkhite-Canada syndrome
68
"Rules of thumb" for colonic polyps
<5mm = hyperplastic with <5% risk of malignancy; 5-10mm = 90% adenoma w/ 1% malignancy risk; 10-20 mm = adenomas w/ 10% malignancy risk; >20 mm = 50% malignant
68
Common cause of rectal bleeding in children
Hamartomatous polyps (Juvenile polyps)
69
Patients with Peutz-Jeghers syndrome have increased risk for what malignancy?
Colon ca, breast ca, uterine and ovarian ca, and early age pancreatic ca
69
Patients with Cowden disease have increased risk for what malignancy?
breast ca, transitional cell ca (urinary tract)
69
Difference b/w lymphoma and lymphoid hyperplasia
lymhoma nodules vary in size. lymhoid hyperplasia nodules are uniform in size.
70
GI metastases often cannot be differentiated from primary tumors by imaging. T or F
TRUE
70
Crohn disease and metastatic disease may also look exactly alike radiographically. T or F
TRUE
71
Radiographic hallmarks of Ulcerative disease
granular mucosa, confluent shallow ulcerations, symmetry of disease around lumen, continuous confluent diffuse involvement
72
CT findings of Ulcerative colitis
1)wall thickening w/ low density submucosal edema 2) narrowing of lumen 3) pseudopolyps and pneumatosis coli with megacolon
73
Assoc extraintestinal diseases of Ulcerative colitis
sacroiliitis, eye lesions, cholangitis, thromboembolic dse
73
Complications of ulcerative colitis
1) strictures in transverse colon and rectum 2) colorectal adenoca 3) toxic megacolon 4) massive hemorrhage
74
Barium studies should be avoided in patients with toxic megacolon. T or F
TRUE
74
Hallmarks of Crohn disease
early aphthous ulcers, later confluent deep ulcers, predominant right colon, discontinuous involvement, assymetric, strictures, fistulas, sinus formation
74
Bleedin rate detection of scintigraphy vs angiography
scintigraphy = below 0.1ml/min; angiography = 0.5 ml/min or greater
74
Radiographic findings of Toxic megacolon
1) marked dilatation >6cm transverse colon with abscence of haustra 2) colonic wall edema and thickening 3) pneumatosis coli 4) evidence of perforation
75
watershed areas of the colon that are most susceptible to ischemic colitis
splenic flexure and descending colon
75
CT findings of Pseudomembranous colitis
1) marked wall thickening 2) accordion sign 3) mild pericolonic inflammation 4) ascites
76
What are the usual locations of the appendix?
Posteromedial aspect of the cecum, may also be pelvic, retrocecal, retrocolic, intraperitoneal, extraperitoneal
77
What is one reliable way of locating the appendix?
The appendix always arises from the cecum on the same side as teh ileocecal valve
78
What is the most common cause of acute abdomen?
Acute appendicitis
79
What are mimickers of AP in women of childbearing age?
Ruptured ovarian cysts, PID
80
What findings of AP can you see in a radiograph?
Appendiceal calculus (14%), appendiceal abscess or periappendiceal inflammation as soft tissue mass in RLQ, deformed lumen of cecum in RLQ, localized ileus
81
What is the imaging technique of choice in women of childbearing age and children in
the diagnosis of AP?
US, although MRI competes with US as diagnostic method of choice
82
the diagnosis of AP? US, although MRI competes with US as diagnostic method of choice What ultrasound scanning technique is quite accurate in providing a definitive diagnosis of AP?
Graded compression technique - slow graded compression applied to area of max tenderness
83
What are the US signs of appendicitis? (4)
1 non-compressible appendix >6mm diam (outer wall to outer wall), 2 shadowing appendicolith, 3 inflamed periappendiceal fat, 4 increased vascularity of wall
