CORE - Urinary Flashcards
Nephrographic phase
100 seconds
Excretory phase
15 minutes
“Too small to characterize”
less than twice the slice thickness
Definition of enhancement on CT
> 20 HU
Definition of enhancement on MRI
> 20% increase in signal intensity
Soft tissue rim sign
small rim of soft tissue (ureter) surrounding an obstructing stone, distinguishing it from a phelobolith
Corduroy appearance of the ureter
leukoplakia (squamous metaplasia); premalignant
Enlarged echogenic kidneys
ARPKD in peds, HIV nephropathy in adults
Young adult with hypertension and renal mass
juxtaglomerular cell tumor; secrete renin => hypertension + hypokalemia
Calcifications in RCC correlates with a better or worse prognosis?
better prognosis
Hyperechoic renal mass with posterior acoustic shadowing
AML; RCCs rarely demonstrate posterior acoustic shadowing
Hyperacute rejection
ABO incompatibility
Acute rejection timing
<3 months
Chronic rejection timing
> 3 months
Multifocal ureteral stenoses
ureteral TB
Total volume for CT cystogram
350 cc or as much as tolerated, instilled by gravity (bag 40 cm above bladder); dilute water soluble contrast (50 cc contrast + 500 cc warm saline)
Blood at the meatus, painful urination, or inability to void after trauma
perform RUG before cystogram
Prostatic utricle
mullerian duct derivative, blind ending male homologue to the uterus and vagina; located at verumontanum
Inflammed glands of Littre (RUG)
urethritis
Most common site of urethral injury
disruption at the urogenital diaphragm and rupture of bulbomembranous urethra
Pyelonephritis on US and CT
decreased perfusion => decreased Doppler flow and hypoenhancing
Another term for renal pyramids
renal medulla (or medullary pyramids)
What are the renal papilla?
tips of the medullary pyramids
Echogenicity of cortex vs. pyramids (adult)
normal pyramids are hypoechoic relative to cortex
Echogenicity of cortex vs. pyramids (neonate)
hyperechoic pyramids; due to Tamm-Horsfall proteinuria
Dromedary hump
normal variant; focal bulge on left kidney related to adjacent spleen
Unilateral renal agenesis associations
unicornuate uterus (females); absent vas deferens/epididymis, seminal vesicle cysts (males)
Mayer-Rokitansky-Kuster-Hauser syndrome
congenital absence of uterus and upper vagina +/- fallopian tube/ovarian abnormalities; assoc. with renal anomlies
Most common renal fusion anomaly
horseshoe kidney
Complications of horseshoe kidney
increases risk of traumatic injury, stasis (infection, stones, TCC), Wilms, UPJ obstruction
Horseshoe kidney associations
Turner’s, Wilm’s
Complications of crossfused renal ectopia
stones, infection, hydronephrosis
Characteristics of RCC mets in liver and brain
hypervascular; enhancing in liver, hemorrhagic in brain
Risk factors for RCC
tobacco, VHL, dialysis-associated kidney disease, family history, tuberous sclerosis (younger age)
Renal mass with macroscopic fat and no calcifications
AML
Renal mass with macroscopic fat and calcifications
RCC (very rare); AMLs do not contain calcification
Renal mass with signal loss on out-of-phase
RCC (clear cell); AMLs do NOT contain microscopic fat
Renal mass with etching artifact on out-of-phase
represents macroscopic fat (that may not be resolvable on other sequences); suggests AML
T2 dark renal mass DDx
papillary RCC, lipid-poor AML, hemorrhagic cyst
Multiple renal masses DDx
RCCs (VHL), RCCs + oncocytomas (Birt-Hogg-Dube), AMLs (tuberous sclerosis)
Most sensitive phase of contrast for RCC
nephrographic (80-100 seconds)
RCC subtype assoc. with VHL
clear cell
RCC subtype assoc. with sickle cell trait
medullary
Hereditary RCC subtype
papillary (may also be related to chronic dialysis)
RCC subtype assoc. with Birt-Hogg-Dube
chromophobe (best prognosis of all subtypes)
Multiple bilateral renal cysts with increased risk of RCC
dialysis-associated cystic kidney disease
Renal mass(es) with preservation of reniform shape
lymphoma (often bilateral)
AML size assoc. with increased risk of hemorrhage
> 4 cm
2nd most common benign renal tumor
oncocytoma
Enhancing renal mass with central “scar” on CT/MR
suggestive of oncocytoma
Oncocytoma vs. RCC on PET
oncocytoma is PET hot, RCC is PET cold
Treatment of oncocytoma
typically resected; if obvious features of oncocytoma, may elect to watch
Bosniak 1
simple cyst, no septa or enhancement; no follow-up
Bosniak 2
hairline septations, fine calcificationl; also homogeneously hyperdense cysts <3 cm; no follow-up
Bosniak 2F
several septations, thick calcification; also homogeneously hyperdense cysts >3 cm; imaging follow-up
Bosniak 3
nodular spetal thickening, enhancing septa/wall; surgical
Bosniak 4
enhancing nodule; surgical
ADPKD associations
liver cysts, Berry aneurysms, seminal vesicle cysts, biliary hamartomas; end result is renal failure
Seminal vesicle cyst DDx
ipsilateral renal agenesis, ADPKD
ARPKD associations
congenital hepatic fibrosis, Caroli disease
Lithium nephropathy
small to normal-sized kidneys with numerous tiny cysts; may cause diabetes insipidus and renal insufficiency
MCDK on renal scintigraphy
no excretory function
Cyst originating from renal parenchyma, may compress collecting system
parapelvic
Cyst originating from renal sinus, mimics hydronephrosis
peripelvic (lymphatic origin); small and multiple
Striated nephrogram DDx
pyelonephritis, acute urinary obstruction, renal vein thrombosis, contusion, post-radiation, ATN (bilateral)
Renal abscess size needing drainage
> 3 cm
Emphysematous pyelonephritis vs. pyelitis
gas in the renal parenchyma vs. gas in the collecting system; both are seen in diabetics
Causes of pyonephrosis
stones, tumor, sloughed papilla (due to pyelonephritis)