Renal imaging

Question 1

flank pain evaluation: goals

Answer 1

• establish presence of ureteral obstruction and determine if stone disease is cause
• if stone present, provide info to assist with therapy (stone location, size, composition, complicating features)
• if no stone present, provide an alternative diagnosis

Question 2

definition: urolithiasis

Answer 2

excessive excretion and precipitation of salts in the urine or a lack of inhibiting substances

Question 3

what sign should you look for in a CT for suspected ureteral obstruction?

Answer 3

soft tissue “rim” sign

Question 4

when is US appropriate for flank pain?

Answer 4

• pregnant woman where stones are suspected

Question 5

what is the initial imaging modality for flank pain?

Answer 5

non contrast CT

Question 6

what is the first line indication for flank US?

Answer 6

• unexplained hematuria or renal dysfunction

- many renal lesions are often discovered incidentally

Question 7

what is a soft tissue “rim” sign?

Answer 7

rim of tissue around the stone at the impaction site on CT = ureteral wall edema

Question 8

what are secondary CT signs of ureteral obstruction from stones?

Answer 8

• perinephric stranding / fluid
• collecting system dilation
• ureteral dilation nephromegaly
• decreased enhancement

Question 9

there is a 96% positive predictive value for stones when which two signs present alongside acute flank pain? what is the negative predictive value when these signs are absent?

Answer 9

• hydroureter
• perinephric stranding
• when absent: negative predictive value 93%

Question 10

what is the first line imaging test in patients with unexplained hematuria or renal dysfunction?

Answer 10

US

Question 11

what is the major method of imaging and characterizing cystic and solid renal lesions?

Answer 11

CT

Question 12

what is the most common renal mass?

Answer 12

simple cyst

Question 13

what is the most cost effective method of defining and confirming a benign cyst?

Answer 13

US

Question 14

what is “enhanced through transmission”

Answer 14

when an US beam passes through fluid, the intensity of the sound energy is not diminished - therefore tissues behind the fluid are more echogenic (brighter) than tissues not behind the fluid

Question 15

hounsfield unit for water

Answer 15

0

Question 16

hounsfield unit for air

Answer 16

-1000

Question 17

bosniak classification of cystic masses

Answer 17

cat 1: simple benign, thin walls
cat 2: benign, may contain thin septa with calcification
cat 2F: increased septa and thicker calcification
cat 3: indeterminate, thick, irregular walls
cat 4: malignant, thick irregular enhancing walls

Question 18

what is the most common solid renal mass?

Answer 18

RCC

Question 19

what does tumefactive mean?

Answer 19

ball-shaped

Question 20

angiomyolipomas occur spontaneously with 30-50% occurring in patients with what condition?

Answer 20

tuberous sclerosis

Question 21

what neoplasms have an infiltrative epicenter in the renal sinus?

Answer 21

• transitional cell carcinoma

- squamous cell carcinoma

Question 22

what neoplasms have an infiltrative epicenter in the parenchyma?

Answer 22

• lymphoma
• infiltrating RCC
• metastases

Question 23

an adrenal mass of ____ cm has a risk of malignancy of up to 85%

how are these managed?

Answer 23

• 6 cm

- surgery

Question 24

benign adenomas contain microscopic ________

Answer 24

lipid

Question 25

what is the single best test for determining whether an incidental adrenal mass is an adenoma?

Answer 25

CT scan with pre and post contrast delayed imaging