Abdominal imaging activities 7 -12

Question 1

briefly describe the etiology of a hypertrophied column of Bertin explain how they are differentiated from pathology

Answer 1

echogenic line that extends from the renal sinus to perinephric fat. The defect is typically located at the junction of the upper and middle thirds of the kidney

During normal development, two parenchymal masses called ranunculi partially fuse. Parenchymal junctional defects occur at the site of fusion and must not be confused with pathologic processes (e.g., renal scar, angiomyolipoma). The junctional parenchymal defect is most often located anteriorly and superiorly, typically at the junction of the upper and middle thirds of the kidney, and can be traced medially and inferiorly into the renal sinus. Usually, it is oriented more horizontally than vertically and therefore it is best appreciated on sagittal scans. Junctional cortical defects are more often shown within the right kidney, although left junctional cortical defects may be detected with favorable acoustic windows.

Question 2

briefly describe the etiology of junctional parenchymal defect and explain how they are differentiated from pathology

Answer 2

Normal variant of unresorbed polar parenchyma from one or both of the two subkidneys that fuse to form the normal kidney.
Sonographic features
indentation of the renal sinus laterally’
bordered by junctional parenchymal defect
located at junction of upper and middle thirds
Continuous with adjacent renal parenchyma
similar colour flow to surrounding parenchyma (demonstration of arcuate arteries)
contains renal pyramids
less than 3cm in size

Question 3

List the most common anomalies of the kidneys

Answer 3

• Hypoplasia:
• Hyperplasia:
• Ectopia:
• Crossed renal ectopia:
• Horseshoe kidney:
• Renal agenesis:
• Supernumerary kidney:
• Duplex collecting system:
• Pelviureteric junction (PUJ) obstruction: Hydronephrosis of the renal pelvis and collecting system down to the level of the proximal ureter is noted.
• Congenital megaureter: The distal ureter does not peritalse effectively, resulting in a spectrum of findings from minor dilatation of the distal ureter to significant hydronephrosis.
• Aberrant vessels: Most commonly at the level of the PUJ a vessel may be seen causing mechanical obstruction to the ureter, resulting in hydronephrosis. This may also occur if the ureter passes posterior to the IVC.

Question 4

Hypoplasia

Answer 4

A small but otherwise normal kidney results in some hypertrophy of the contralateral kidney to compensate. It is only a clinical concern if the variant is bilateral or if the dominant kidney is damaged.

Question 5

Hyperplasia

Answer 5

A large but otherwise normal kidney results from increased workload following reduced function of the contralateral kidney. Focal forms of hypertrophy may occur as spared portions of a diseased kidney hypertrophy. Differentiation between focal hypertrophy and renal masses is difficult.
• Fetal lobulation: A lobular outline of the renal capsule is noted, especially in paediatrics. This embryological lobulation may persist and be noted in adults.

Question 6

Ectopia

Answer 6

Failure to ascend or, in rarer cases, ascent into the thorax, results in an ectopic kidney. Once the renal fossa is found to be empty you should search diligently for an ectopic kidney before diagnosing renal agenesis. Pelvic kidneys are often beneath the bowel and malrotated, making them difficult to find and then image. A full urinary bladder may be of help as will a graded compression technique.

Question 7

Crossed renal ectopia

Answer 7

If a kidney is absent and not seen in the pelvis, it may be located on the other side of the abdomen. It may be found in the contralateral pelvis or fused with the other kidney.

Question 8

Horse shoe kidney

Answer 8

A horseshoe kidney appears as a kidney on each side of the abdomen, with the lower poles fused together across the midline. Clues to a horseshoe kidney are:
o slight inferior location of one or both kidneys;
o malrotation of the lower poles;
o no clearly defined lower pole to either kidney; and
o lower poles tend to ‘reach’ toward the midline.
Scanning in the midline reveals the isthmus of renal tissue superficial to the aorta. This is usually a bridge of renal tissue that is readily identifiable if you are looking for it. However, the bridge may consist of only a thin fibrous band and that is difficult to identify. Do not mistake the isthmus of a horseshoe kidney for para-aortic lymphadenopathy.

Question 9

Renal agenisis

Answer 9

This may be diagnosed when all other attempts to locate the missing kidney have failed. However atrophic kidneys are sometimes difficult to identify so agenesis is a difficult diagnosis to make based on ultrasound examination.

Question 10

Supernumery kidney

Answer 10

An extra independent small kidney functions separately from the two kidneys.

Question 11

Duplex collecting system

Answer 11

This is the most common anomaly resulting from paired collecting systems of variable degrees.

Question 12

Does the absence of a urinary jet indicate obstruction? Under what circumstance might a urinary jet, although present, not be seen?

Answer 12

Renal failure, incorrect probe position, incorrect colour Doppler settings and dehydration may cause a urinary jet to be present and not seen.

Question 13

Describe three areas of ureteric narrowing which are common sites for a calculus to become lodged.

Answer 13

If a stone passes into the ureter, the calculus may lodge in three areas of ureteric narrowing: just past the UPJ; where the ureter crosses the iliac vessels; and at the UVJ (ureterovesical junction – where the ureter enters the bladder) . The very small diameter of the UVJ (1-5 mm) accounts for the large percentage of calculi that lodge within the distal ureter. Approximately 80% of stones smaller than 5 mm will pass spontaneously.

Question 14

List other entities which may mimic a renal calculus.

Answer 14

including intrarenal gas, renal artery calcification, calcified sloughed papilla, calcified transitional cell tumor, alkaline-encrusted pyelitis, and encrusted ureteral stents.

Question 15

List the sonographic appearances that may be seen in acute pyelonephritis.

Answer 15

renal enlargement
compression of the renal sinus
decreased echogenicity (secondary to edema) or increased echogenicity (potentially from hemorrhage)
loss of corticomedullary differentiation
poorly marginated mass(es)
gas within the renal parenchyma
and focal or diffuse absence of color Doppler perfusion corresponding to the swollen inflamed areas.

Question 16

Describe the sonographic appearances of chronic pyelonephritis

Answer 16

• renal scarring
• renal atrophy
• renal cortical thinning
• compensatory hypertrophy of residual normal tissue (which may mimic a mass lesion)
• calyceal clubbing: secondary to retraction of the papilla from overlying scar
• thickening and dilatation of the calyceal system
• overall renal asymmetry

Question 17

describe the Robson criteria for staging renal cell carcinoma

Answer 17

1. I: Tumor confined within renal capsule
2. II: Tumor invasion of perinephric fat
3. III: Tumor involvement of regional lymph nodes or venous structures
4. IV: Invasion of adjacent organs or distant metastases

Question 18

List predisposing factors to ATN, which may lead to increased renal cortex echotexture.

Answer 18

If drugs, metals or solvents have caused ATN the kidneys will appear large and echogenic.

Question 19

List possible causes of acute cortical necrosis

Answer 19

The cause is likely related a severe systemic illness resulting in transient intrarenal vasospasm, intravascular thrombosis or glomerular capillary endothelial damage. This may include severe haemodynamic shock (traumatic blood loss, postpartum haemorrhage, septic shock, venom toxin, transfusion reaction, severe dehydration), haemolytic uraemic syndrome (HUS) (multisystem thrombotic microangiopathic disease and renal transplantation.

Question 20

briefly describe ACN sonographic appearances

Answer 20

At initial presentation the renal cortex is hypoechoic. As time goes on kidneys atrophy and the cortex may calcify.

Question 21

Describe the formation and appearance of parapelvic cysts

Answer 21

Parapelvic cysts may originate from lymphatics or embryologic rests and appear as well-defined, anechoic, renal sinus masses. If they have haemorrhaged, internal echoes will be seen in the cysts.

Question 22

explain how parapelvic cysts may be differentiated from hydronephrosis

Answer 22

Parapelvic cysts originate from the adjacent parenchyma and protrude into the renal sinus. Careful scanning will show the renal pelvis is separate from the parapelvic cyst.

Question 23

explain what other imaging modalities may be useful in differentiating parapelvic cysts from hydronephrosis.

Answer 23

CT IVP is a useful alternative imaging in differentiating parapelvic cysts from hydronephrosis. A combination of non-contrast, portal venous and excretory phase imaging allows complete assessment of the renal tract and will show definitively the parapelvic cyst(s) do not communicate with the renal pelvis. MRI may also be helpful.

Question 24

List other anomalies associated with autosomal dominant polycystic kidney disease.

Answer 24

• liver cysts (30%-60%)
• pancreatic cysts (10%)
• splenic cysts (5%)
• cysts in thyroid, ovary, endometrium, seminal vesicles, lung, brain, pituitary gland, breast, and epididymis
• cerebral berry aneurysms (18%-40%)
• abdominal aortic aneurysm
• cardiac lesions
• colonic diverticula

Question 25

Describe the ultrasound criteria used to make a diagnosis of autosomal dominant polycystic kidney disease in patients with a family history. Describe how the criteria change with the age of the patient.

Answer 25

<30 years – Require two renal cysts unilateral or bilateral
30-59 – Require two cysts in each kidney
>60 years – Require four cysts in each kidney
Fewer than two renal cysts in at risk individuals older than 40 is sufficient to rule out ADPKD.

Question 26

What are the anatomic relationships of the right adrenal gland

Answer 26

The right adrenal gland is examined in a similar fashion to the upper pole of the right kidney. A number of options exist and the optimum acoustic window will vary from patient to patient. The right adrenal gland sits between the upper pole of the right kidney, and the inferior vena cava. This location allows the liver to be used as an ideal acoustic window.

Question 27

describe the typical clinical presentation of a patient with a pheochromocytoma

Answer 27

Pheochromocytomas are functional neuroendocrine tumors associated with catecholamine hypersecretion and as such clinical symptoms include refractory hypertension, palpitations, flushing, diarrhea, and weight loss.

Question 28

list the possible primary sites of pheochromocytoma

Answer 28

Sites include the sympathetic chain, urinary bladder, organ of Zuckerkandl and rarely thoracic paraganglioma.

Question 29

list structures which may be mistaken for an adrenal mass

Answer 29

• Splenule
• Pancreatic parenchymal lobulation
• Pancreatic tail mass
• Gastric fundus
• Renal mass
• Lymph node
• Small bowel
• Thickened diaphragmatic crus

Question 30

list the common primary sites for adrenal metastases

Answer 30

• Lung
• Breast
• Hepatocellular
• Thyroid
• Renal
• Pancreatic
• Gastrointestinal
• Melanoma

Question 31

list the common primary sites for adrenal metastases

Answer 31

• Lung
• Breast
• Hepatocellular
• Thyroid
• Renal
• Pancreatic
• Gastrointestinal
• Melanoma

Question 32

An adrenal mass may displace the splenic vein:

a) Anteriorly
b) posteriorly
c) medially
d) laterally

Answer 32

Anteriorly -

Question 33

Which of the following can be confused with the normal right adrenal gland

a) crus of the diaphragm
b) bowel gas
c) renal cyst
d) aorta

Answer 33

crus of the diaphragm -

Question 34

Which statement is false about adrenal carcinoma?

a) These tumors usually produce steroids and are associated with one of the hyperadrenal syndromes.
b) It is a nonsteriod-producing tumor.
c) There is a strong tendency for invasion into the adrenal vein, inferior vena cava, and lymph glands.
d) Metastases to regional and periaortic nodes are common.

Answer 34

It is a nonsteriod-producing tumor. -

Question 35

Why is it important to note the position of a focal wall thickening relative to the vesicoureteric junctions?

Answer 35

The position of focal wall thickening or a bladder wall mass relative to the vesicoureteric junctions is important as bladder tumours often present with symptoms of renal obstruction caused by the mass.

Question 36

name the four types of urachal anomalies

Answer 36

1. Patent urachus (50%)
2. Urachal cyst (30%)
3. Urachal sinus (15%)
4. Urachal diverticulum (5%)

Question 37

What are the four layers of the wall of the GIT?

Answer 37

Mucosa, sub mucosa, muscularis propria and serosa or adventitia

Question 38

Describe the normal ‘gut signature’ as it appears on an ultrasound image

Answer 38

Superficial mucosa/interface ECHOGENIC
Muscularis Mucosa HYPOECHOIC
sub mucosa ECHOGENIC
muscularis propria HYPOECHOIC
serosa or adventitia ECHOGENIC
The muscle layers are hypoechoic. The submucosa and superficial mucosa layers are hyperechoic. There is a small amount of fluid and air in the gut lumen.
The sonographic layers appear alternately echogenic and hypoechoic;

Question 39

Describe the sonographic ‘pseudokidney’ appearance and briefly discuss the relevance of the finding.

Answer 39

The pseudokidney of intussusception is an ultrasound finding in some cases of intestinal intussusception. It refers to the longitudinal ultrasound appearance of the intussuscepted segment of bowel which mimics a kidney. The hypoechoic external rim corresponds to thickened gut wall, whereas the echogenic center relates to residual gut lumen or mucosal ulceration.
The fat-containing mesentery which is dragged into the intussusception, containing vessels, is reminiscent of the renal hilum, with the renal parenchyma formed by the oedematous bowel.

A pathologically significant lesion was found in more than 90% of patients with this pattern.

Question 40

Define Crohn’s disease

Answer 40

Inflammatory bowel disease (IBD) comprises Crohn disease and ulcerative colitis. Crohn disease, also known as regional enteritis, is an idiopathic inflammatory bowel disease characterised by widespread discontinuous gastrointestinal tract inflammation. The terminal ileum and proximal colon are most often affected.

Question 41

List the common complications of Crohns disease

Answer 41

The natural course of the disease includes alternating periods of active inflammation and remission with a strong tendency to complicate over time, with the development of penetrating and/or fibrostenotic lesions. This may cause ulceration, fistula and stricture formation. Strictures may lead to bowel obstructions.

Question 42

Briefly describe the typical sonographic findings of Crohn’s disease

Answer 42

The classic features of Crohn disease are wall thickening, inflammatory fat, lymphadenopathy, and hyperemia.
• small bowel wall thickening (>3-4 mm)
• affected segments lose peristaltic activity
• loss of mural stratification
• bowel wall hyperaemia
• mesenteric lymphadenopathy
• free intraperitoneal fluid

Question 43

List the sonographic appearances which should be considered as part of an investigation of the GIT where the patient has presented with an acute abdomen.

Answer 43

we should consider the appearance of Gas, fluid, masses, perienteric soft tissue, gut and clinical interaction as we sonographically assess the gut and what it suggests.
to a certain extent intraluminal gas is normal however extraluminal is not and where it is found (Intraperitoneal, Retroperitoneal, Gut wall, Gallbladder/biliary ducts, Portal veins) can gives clues as to the pathology and it's location.
Gas
- Intraluminal
- Extraluminal
    Intraperitoneal
    Retroperitoneal
    Gut wall
    Gallbladder/biliary ducts
    Portal veins
Fluid
- Intraluminal
    Normal calibre gut
    Dilated gut
- Extraluminal
    Free
    loculated
Masses
- Neoplastic
- inflammatory
Perienteric soft tissue
 -Inflamed fat
- Lymph nodes
Gut
- Wall
- Calibre
- peristalsis
Clinical interaction
- Palpable mass
- Maximal tenderness
- Murphy's sign
- McBurney's sign

Question 44

Elaborate on sonographic appearances of the gut in acute abdomen and why they are important

Answer 44

The abdominal ultrasound evaluation should include visible gas and fluid (to determine their luminal or extraluminal location), the perienteric soft tissues, and the GI tract itself.
Identification of gas in a location where it is not usually found is a clue to many important diagnoses. The gas itself may appear as a bright, echogenic focus, but the identification of the artifacts associated with the gas pockets usually leads to their detection. These include both ring-down artifact and “dirty” shadowing. Extraluminal gas may be intraperitoneal (Free intraperitoneal air) or retroperitoneal, and its presence should suggest either hollow viscus perforation or infection with gas-forming organisms. Nonluminal gas may be easily overlooked, particularly if the collection is large. Gas in the wall of the GI tract, pneumatosis intestinalis, with or without gas in the portal veins, raises the possibility of ischemic gut.

Question 45

What are the normal measurements of the adult appendix?

Answer 45

The normal measurements of the adult appendix are a wall thickness less than 3 mm and a total diameter of less than 6 mm.

Question 46

What are the sonographic features consistent with acute appendicitis?

Answer 46

Blind ended
noncompressible
Aperistaltic tube
Gut signiture
Arises from the base of the cecum
Diameter greater than 6mm
The inflamed appendix has an average diameter of 9mm and is often surrounded by hyperechoic, non-compressible, inflamed fat. 

In contrast the diameter of the normal appendix is usually <6mm and is well compressible, more mobile and never surrounded by inflamed fat.

Question 47

Define the four major types of mechanical obstruction.

Answer 47

Obturation obstruction, related to blockage of the lumen by material in the lumen;
Intrinsic abnormalities of the gut wall, associated with luminal narrowing;
Extrinsic bowel lesions, including adhesions.
Strangulation obstruction develops when the circulation of the obstructed intestinal loop becomes impaired.

Question 48

List the sonographic features of mechanical obstruction.

Answer 48

•	dilated bowel loop (diameter > 3 cm)
•	ineffective peristalsis
    o	results in "to-and-fro" or "whirling" appearance of intra-luminal contents
•	prominence of the valvulae conniventes
    o	present in dilated jejunal loops

Question 49

Describe the classic ultrasound appearance of interssusception.

Answer 49

A sonographic appearance of multiple concentric rings, related to the invaginating layers of the telescoped bowel and seen in cross section, is virtually pathognomonic.

Question 50

Why would a patient with a femoral hernia complain of a swelling and discomfort in the leg?

Answer 50

A patient with a femoral hernia may complain of a swelling and discomfort in the leg due to the effect of the femoral hernia compressing the common femoral vein as it passes through the femoral ring.

Question 51

Why does the sonographer ask the patient to ‘strain’ during an ultrasound examination for hernias?

Answer 51

Dynamic scanning with the patient straining is used to determine if herniation occurs with increased intra-abdominal pressure.
Dynamic maneuvers can cause the fat within a hernia to move, making the hernia contents more conspicuous. The direction of movement can be helpful, because movement of surrounding tissues is almost always in the anteroposterior (AP) direction, whereas hernia contents often move horizontally or obliquely during compression maneuvers. Hernia contents may change with dynamic maneuvers. Finally, reducibility and tenderness can be assessed.
Some hernias become visible only during the Valsalva maneuver. In other cases, hernia sacs that can be seen in quiet respiration elongate and widen during the Valsalva maneuver. Hernias that appear to contain only fat during quiet respiration may be shown to contain bowel during the Valsalva maneuver. In general, hernia sacs should become larger with the Valsalva maneuver. If they stay the same size, this is worrisome for incarceration.

Question 52

.Spigelian hernias arise through a weakness in:

(a) the deep inguinal ring
(b) the central linea alba
(c) the junction of rectus abdominis and lateral abdominal wall muscles
(d) the superficial inguinal ring

Answer 52

(c) the junction of rectus abdominis and lateral abdominal wall muscles

Question 53

What is the thin echogenic structure seen joining the rectus abdominis muscle bellies?

Answer 53

The thin echogenic structure seen joining the rectus abdominis muscle bellies is the linea alba.

Question 54

Describe the advantages of sonography over fluoroscopy for evaluation of diaphragmatic paralysis.

Answer 54

Ultrasonography is good for the evaluation of the structure and dynamic function of the diaphragm. It is accurate, reproducible, and relatively easy to learn. The modality is portable, which is very important for critically ill patients on mechanical ventilation, and uses no ionizing radiation.

The direct quantitative information on US is immediately apparent, while the indirect measurement using fluoroscopy takes longer and is limited due to geometrical error producing magnification errors and errors due to rotation, as a result of using a divergent beam.

Identification of Diaphragm Paralysis
Direct visualization of the diaphragm can provide a portable, non invasive bedside method for detection of unilateral or bilateral paralysis in patients with the clinical suspicion of diaphragm dysfunction.

Identification of the Etiology of Diaphragm Paralysis
Direct visualization of the diaphragm can identify intrinsic or extrinsic pathology such as diaphragm eventration, hernias, pleural fluid, subphrenic abscess, hepatic abscess, metastatic disease, thoracic masses or rupture causing diaphragm paralysis.

Prognosis after Diaphragm Paralysis
In patients with serial ultrasound measurements after diaphragm paralysis, an increase in thickness of the diaphragm during inspiration, which probably correlates with re-innervation, has been associated with improvement in inspiratory function and increases in vital capacity over time.

Question 55

Define ‘ascites’.

Answer 55

Ascites is the excess build-up of any type of fluid within the peritoneal cavity (serous fluid, blood, urine, bile, etc.).
The peritoneal cavity normally contains approximately 50–75 mL of clear fluid, which functions as a lubricant.

Question 56

What is another name for Douglas’ Pouch?

Answer 56

Douglas’ Pouch may also be called the retrovesical space that is divided by the uterus into the anterior vesicouterine recess and posterior rectouterine sac.

Question 57

The sandwich sign represents a mass infiltrating the mesenteric leaves and encasing the superior mesenteric artery (true or false).

Answer 57

The sandwich sign represents a mass infiltrating the mesenteric leaves and encasing the superior mesenteric artery (true or false). True.

Question 58

Where is Morrison’s Pouch?

Answer 58

Morrison’s Pouch is located in the subhepatic space, anterior to the right kidney and posterior to the right lobe of the liver.

Question 59

Where is Douglas’ Pouch?

Answer 59

Douglas’ Pouch is located posterior to the bladder; in females it is between the uterus and rectum; in males it is between the bladder and rectum.

Question 60

What is the name given to linear thickenings in the diaphragm?

Answer 60

The name given to linear thickenings in the diaphragm is diaphragmatic slips.