Kidney flashcards
Bright fluid helpful in identifying T2 sequence
CSF, Stomach, GB, “Perinephric sweat” (fluid around kidneys)
Delayed nephrogram
Defines obstruction. Kidney not enhancing like it should on nephrogram.
Ddx for bilateral delayed nephrogram (4)
bilateral obstruction, contrst nephropathy, systemic hypotension, myeloma kidney
Persistent nephrogram
Kidney is still enhancing long after contrast was given. Likely renal failure.
Renal mass protocol phases
Unenhanced. Nephrographic (100 seconds), pyelographic (excretory) phase (15 minture delay)
What can be seen on pyelographic phase
hyronephrosis vs. renal sinus cyst. Dilated calyces from reflux nephropathy (rather than cystic mass), calyceal diverticulum
CT enhancement quant
<10 HU: no enhancement. 10-19 HU: equivical. >20; enhancement
MR enhacement quant
<15%;none. 15-19; equivical, >20% enhancement
When are lesions “too small to characterize?”
If they are smaller than twice the slice thickness
Indications for renal mass biopsy (5)
Mets vs. RCC in known primary. Renal infection vs. cystic neoplasm. AML vs. RCC. To ensure correct tissue dx prior to ablation. To definitively diagnose suspcious renal mass in pt who is high risk for nephrectomy
Solid renal masses (6)
RCC, AML, Oncocytoma, lymphoma, non-neplastic masses (infection, AVM), renal pseudotumors (hypertrophied column of bertin, persistent fetal lobation
RCC risk factors
smoking, acquired cystic kidney disease, VHL, tuberous sclerosis
Types of RCC (5)
Clear cell, Papillary, chromophobe, collecting duct carcinoma, medullary carcinoma
Clear Cell RCC
Most common RCC, enhances avidly (equal to cortex), bilateral in VHL
Papillary RCC
2nd most common type. Hypovascular, enhances less than clear cell (enhancement is less than cortex). T2 dark
Chromophobe. a/w what?
A/w Birt Hoge Dube, Best prognosis.
Collecting duct RCC
rare, poor prognosis
Medullary RCC. Effects who?
Effects men w/ Sickle Cell TRAIT. Terrible prognosis
describe Robson staging of RCC
I; w/in renal renal capsule. II; out of capsule, but still in Gerota’s fascia. III; vascular or lymph node involvement (A; Renal vein or IVC, B; lymph nodes, C; venous and lymph nodes. IVa; through gerota’s fascia, Ivb; distant mets
Robson staging of RCC, which are rescectable?
Stages I-III are resectable
Bland thrombus vs. tumor thrombus
Enhancement, flow on u/s
Which is worse? RCC in renal vein, or RCC in adrenal gland
In Adrenal gland is worse (stage 4). Renal vein is just Stage 3
Fatty mass w/ calcification in the kidney is concerning for ___, in the retroperitoneum is concerning for ___
RCC, Liposarcoma
AML Pathognomonic imaging finding
macroscopic fat in a noncalcified renal lesion
AML; association. Treatment.
Tuberous sclerosis. Embolize if >4cm, due to risk of hemorrhage
Type of fat in AML?
Macroscopic. Will not drop out on dual phase MRI.
Hyperechoic kidney lesion on u/s (what is it most likely? What is next step in management?)
Its most likely an AML, but next step in management is to get a CT or MR w/ contrast to differentiate from RCC (especially papillary subtype,which is hyperechoic)
Ddx; T2 hypointense lesion in kidney (3)
Lipid poor AML, hemorrhagic cyst, papillary RCC
Oncocytoma
Look like RC, but have a central scar/spoke wheel. a/w Birt Hogg Dube. These are still resected, because it may be RCC.
Homogenous mass in kidneys is likely __
lymphoma. Usually B-cell. Homogenous, hypovascular, PET Avid
Renal lymphoma patterns (4)
Multiple lymphomatous masses. Solitary renal mass. Diffuse lymphomatous infiltration causeing nephromegaly, direct extension of rp disease
Non-neoplastic solid renal masses (2)
Infection (focal nephritis, abscess), AVM (avid enhancement)
Renal pseudotumors
Hypertophied column of Bertin. Persistant fetal lobuation (indentation of cortex. Presence of septa of Bertin on either side).
Birt Hogg Dube. Inheritance, 3 systems effected?
Aut. D. syndrome. Dermatologic lesions. Cystic lung disease, multiple renal oncocytomas, and RCCs.
Tuberous sclerosis features. Type of mutation. Findings (3 categories)
Aut D. Tumor suppressor gene mutation. Seizures, developmental delay, mostly benign tumors. Renal cysts, AMLs, slight increase risk of RCC, Cerebral hamartomas. Cardiac rhabdomyomas(sarcomas). Skeletel osteomas. Pulmonary lymphangioleiomyomatosis.
Tuberous sclerosis tumor locations (3 kidney, 1 in brain, heart, bones, lungs)
Renal cysts, AMLs, slight increase risk of RCC, Cerebral hamartomas. Cardiac rhabdomyomas(sarcomas). Skeletel osteomas. Pulmonary lymphangioleiomyomatosis.
Neoplastic differential of a cystic renal mass (3)
Cystic RCC. Multilocular cystic nephroma (enhancing septa. Baby boys and middle age women). Mixed epithelial stromal tumor (MEST); Middle aged women
Non-neoplastic differential for cystic renal mass
Renal abscess, Hemorrhagic renal cyst
Types of renal cysts (3)
Simple renal cyst, Renal sinus cyst (parapelvic, peripelvic), hyperdense (>70HU, likely secondary to prior hemorrhage)
Renal sinus cyst (Para vs. peri)
Parapelivic is a normal renal cotical cyst herniating into pelvis. PERIpelvic cyst; lymphatic in origin, due to lymphatic obstruction, small, multiple.
Bosniak CT classification?
Category I: simple cyst. II: three of fewer septa, maybe small calcs. also includes small (<3cm) high density cyst w/o enhancement. IIF: may have thick and nodular mural calcifications. walls may slightly enhance. Also includes large (>3cm) hyperattenuating cysts w/o enhancement III: thick, irregular wall, enhancement. Class IV: Enhancing nodular component
Bosniak cystic renal mass categories?
Category I Benign simple cyst Category 2 Benign Complicated (Iif has a small risk of malignancy) Category 3 Indeterminate cystic lesions Category 4 Malignant cystic tumors (enhancing soft tissue)
2 Questions to ask when assessing cystic kidney disease
Size of kidneys? Are other organs involved?
Cystic kidney disease (3 + a rare cause)
APCKD, VHL, dialysis related cystic disease. Lithium kidney is a rare cause
ADPCKD. How do they present
Adult, normal at birth, presents w/ HTN, hematuria, upper abdominal pain. Big cysts, liver involved.renal failure by middle age, berry aneurysms are deadly
ARPKD
Abnormal at birth. Lots of little cysts. Hepatic fibrosis (inverse to degree of renal disease)
Polycystic kidney disease relationship w/ RCC
Cystic kidney diesase does not increase risk of RCC. But it will cause renal failure, and dialysis does increase risk of RCC
Lithium kidney
Microcysts, normal sized kidneys, renal failure
CT findings of pyelonephritis?
Renal enlargement. Multifocal wedge-shaped hetergeneous areas. Parenchymal striations. Decreased enhancement. Perinephric stranding. Thick urothelium.
In reflux nephropathy scarring first develops where?
At renal poles.
DDx for unilateral enlarged kidney (4)
Pyelonephritis, acute ureteral obstruction, renal vein thrombosis, compensatory hypertophy.
DDx for striated nephrogram (7)
Pyelonephritis, renal infarct, renal veinthrombosis/vasculitis, renal contusion, acute urinary obstruction, renal tumor, radiation nephritis.
focal lobar nephronia
Old name for focal pyelonephritis
Pyelonephritis can have mild hydronephrosis. Explain this
This is thought to be due to bacterial endotoxin causing reduced peristalsis. Should not be confused w/ obstructive uropathy.
Pyonephrosis
Infection of an obstructed collecting system. Tx is emergent perc neph
Renal abscess treatment
<3cm; abx. >3cm - drainage.
Ddx small scarred kidneys. (unilateral, bilateral)
Reflux nephropathy, Previous renal surgery, renal infarcts, analgesic nephropathy
Emphysematous pyelonephritis versus emphysematous pyelitis?
Emphysematous pyelonephritis: diabetes, infection, gas in renal parynchema, emergency nephrectomy. Emphysematous pyelitis: gas in pelvis and calyces (trauma, iatragenic, infection), not a surgical urgency.
xanthogranulomatous pyelonephritis?
Chronic infection due to obstructing calculi, leading to replacement of renal parenchyma w/ fibrofatty inflammatory tissue. Middle-aged females with UTIs and constitutional symptoms, anemia, hematuria.
XGP common organisms. CT findings
Proteus mirabilis, E. coli. Fatty replacement. Perinephric inflammatory stranding, staghorn calculi. Bear paw sign of hypoattenuating fibrofatty masses arranged in a radial pattern.
XGP treatment
nephrectomy
HIV nephropathy.
Enlarged hyperechoic kidneys. a/w Focal segmental glomerulosclerosis (FSGS)
Renal TB
Parenchymal calcification, scarring, papillary necrosis, infundibular stricutres. Autonephrectomy (putty kidney)
Kidney stones. most common type?
Calcium oxalate stones are most common.
Kidney stones. which can’t be seen on Xray? Cant be seen on CT?
Uric acid, xanthine, matrix, pure struvite, indinavir unseen on plain film. Indinavir stone (HIV drug) not seen on CT
kidney stones; classic for wome w/ UTI’s, stones w/ XGP, congenital anomaly that predisposes to stones
Struvite stones are classic for women w/ Recurrent UTIs. Staghorn stones are seen w/ xanthogranulomatous pyelonephritis. Horseshoe kidney gets more kidney stones.
Signs of ureteral stone
Tissue rim sign. Loss of white renal pyramids.
Tissue rim sign?
Halo of soft tissue that surrounds ureter stone. Distinguishes ureteral stone from phlebolith
Phlebolith distinguishers?
tail sign (vein), central lucency, round
Ddx for papillary necrosis (postcard)
Pyelonephritis, obstruction, Sickle, TB, Cirrhosis, Analgesics (Nsaids), Renal vein thrombosis, Diabetes mellitus.
3 uroradiologic signs of papillary necrosis
ball on tee sign (contrast filling central papilla), lobster claw sign (contrast filling only periphery of papilla), signet ring sign (contrast surrouding sloughed papilla)
Ddx medullary nephrocalcinosis (5)
Hypercalcemic state (hyperparathyroidism, sarcoid), medullary sponge kidney, RTA 1, furosomide therapy in child. Papillary necrosis.
Ddx cortical nephrocalcinosis (5)
Acute cortical necrosis, hyperoxaluria, alport syndrome (hereditary nephropathy and deafness). Autosomal recessive PCKD. (also chronic glomerulonephritis and transplant rejection).
Cortical necrosis
Rare form of renal injry from acute ischemic necrosis of renal cortex. May be due to small vessel vasospasm, or systemic hypotension.
Ddx Echogenic renal mass
AML (shadowing is specific), RCC, calculus, gas, Milk of calcium, sloughed papilla.
Ddx extracalyceal contrat medium
Tubular ectasia, calyceal diverticulum, papillary necrosis.
Renal trauma grading
I; contusion, subcapsular hematoma. II; superficial laceration (<1cm), confined perinephric hematoma. III; Deeper laceration (>1cm) w/o extravasation. IV; deep lac extending to collecting system, or injury to renal artery/vein w/ contained hemorrhage. Needs surgeical repair. V; shattered kidney, avulsion of renal hilum.
Other renal injuries not included ingrading system
Renal artery thrombosis. Pseudoaneurysm.
Page kidney
Subcapsular hematoma causing compression of renal parenchyma, increased renin secretion, increased HTN. Tx is perc drainage.
Most common sites for RCC metastases?
lungs mediastinum bone liver contralateral kidney adrenal gland brain
2 types of renal sinus fat proliferation?
Renal sinus lipomatosis: increased fat with little mass effect. Replacement lipomatosis: renal atrophy, massive fat.
Horseshoe kidney; what does it get stuck on?
IMA. More susceptible to trauma, stones, obstruction, infection, reflux. Bc of chronic insults, more susceptible to cancers.
Horseshoe kidney is a/w what tumors and what syndrome?
TCC, Wilms, RCC, renal carcinoid. Turner’s syndrome
Turner’s syndrome
Horseshoe kidney, streak ovaries, Bicuspid aortic valve, coarctation.
Treatment of FMD and atherosclerotic renal artery
FMD = angioplasty. Atherosclerosis = angioplasty + stenting
RAS angiography (intervention worthy gradient parameters for mean and peak systolic pressure of RA vs. Aorta)
> 10mmHg Mean systolic pressure. OR. >20mmHg peak systolic pressure
RAS by duplex RA:Aorta PSV ratio
> 3.5 ratio of Peak Systolic Value RA/PSV = at least 60% stenosis.
RAS is a/w what syndrome?
NF1
NF1
Lateral meningocele, Neurofibromas, optic gliomas, sphenoid wing dysplasia, RAS.
Nuc med test to look for RAS
Captopril renogram
Nucs chemicals used for kidney
TcDTPA, MAG3,
Kidney scans are done in what plane (2 exceptions)
Posterior plane (because kidney is posterior, so you want it close to the camera), except for horseshoe kidney and transplant kidney, because they are anterior
Nucs Tc Mag 3 test (3 looks like an S)
Secretion (ERPF). Sick kidney will hold hold contrast (stay up) on Captopril test (that’s why it needs magnum, if you know what I mean)
Nucs Tc DTPA is used to test
Filteration (GFR) Sick Kidney Can’t get it up after captoril (D can’t get up if its sick)
Captopril renogram preparation
Need to stop Ace inhibitor at least 3 days prior. NPO 6 hours prior.
Mag 3 - 2 phases of the study. Main reason for study.
Flow Phase (kidney gets darker), renogram phase (kidney gets lighter, bladder gets darker). Study is to differntiate ATN and acute rejection
Ddx Mag 3 - normal flow with abnormal renogram phase
ATN (if early after transplant), drug toxity (cyclosporin) (if later after transplant)
Ddx Mag 3 - abnormal flow and renogram phase
Acute rejection
ATN vs. Cyclosporin tx vs. acute rejection
ATN: early (days), normal perfusion, bad excretion. Cyclosprin; Late, normal perfusion, bad excretion. Acute rejection; early (days) bad perfusion, bad rejection
Causes of hydronephrosis
Obstruction, reflux, pregnancy, megaureter
Resistive indices formula
RI = (PSV-EDV)/PSV
how can you use RI to evaluate for obstruction
RI can be elevated in ACUTE obstruction (cytokines cause arterial constriction). An RI >0.7 on affected side, or difference of >0.1 between kidneys suggests obstruction.
Ddx renal infection
Pyelonephritis, renal abscess, emphysematous phyelonephritis, TB pyelo, XGP, pyonephrosis, HIV nephropathy
pyelonephritis on u/s
diffuse; normal kidney. General edema. Focal; hypoechoic lesion, disrupts corticomedullary junction
Surgical complications following transplants
Ureteral obstruction. Fluid collection.
Post-transplant fluid collections (4)
Hematoma (post-op), Urinoma; (1-2 weeks), will have tracer. Abscess (3-4 wks) Lymphocele; 4-8 weeks, no tracer.
Vascular complications following renal transplant (3)
Renal vein thrombosis (reversal of diastolic flow). RAS (parvus tardus). Pseudoaneurysm (usually due to biopsy)
Medical complications after transplant
rejection (hyperacute, acute, chronic), ATN (occurs in postop days). Drug toxicity (cyclosporine)
Post-transplant lymphoproliferative disorder. Due to?
Due to EBV. Can occur anywhere. Amorphous hypoechoic mass. Will have doppler flow.
Types of ureteroceles (3)
Orthoptic ureterocele (most commonly adults), ectopic ureterocele (children), pseudoureterocele (intussusception of distal ureter into bladder. May be due to radiation cystitis, or UVJ stone).
ureterocele; imaging appearance on u/s. association
Looks like ‘cobra’s head’, a/w duplicated system.
Weigert meyer rule
Upper pole obstructs and inserts inferior and medial. Lower pole refluxes and inserts superior and lateral
Duplicated system; How low may the ectopic ureters insert
Males: as low as prosthetic urethera. Females: as low as vagina
Urethra cancers by location (prostatic, penile, diverticulum)
Prostatic urethra (TCC), Penile urethra (SCC), Diverticulum (Adenocarcinoma)
Cancers of urinary system
TCC (Most common), SCC (Schistosomiasis), Adenocarcinoma (urachal remnant)
Transitional cell cancer (location). Associations
Bladder»>pelvis>Ureter (distal). Aniline dyes, tobacco, analgesics, Balkan nephropathy.
Schistosomiasis a/w ..
SCC of bladder
Adenocarinoma of urinary system a/w
urachal remenant. Calcifications
CT urogram, typical protocol
Patients give PO water, IV saline, And furosomide to distend bldadder. Then 3 phases obtained. Split bolus w/ 2 phases can be considered for younger patients.
Malignant ureteral disease (1). Imaging
TCC. Seen as filling defect. If you see it, should also evaluate bladder.
Benign ureteral masses (3)
Fibroepithelial polyp, urothelial papilloma, inverted papilloma
Fibroepithelial polyp.
most common benign tumor of ureter. Affects proximal ureter. Has long stalk and appears as elongated smooth tubular lesion.
Urothelial papilloma
rare, benign neoplasm of bladder or ureter. May be large and mimic malignancy.
Inverted papilloma
Benign mass w/ a central core of urothelium.
Inflammatormy/infectious ureteral disease (4)
Ureteritis Cystica, Leukoplakia (Squamous metaplasia), Malacoplakia, Ureteral TB.
Ureteritis Cystica
Benign response to chronic urinary tract inflammation. Small subepithelial cysts.
Leukoplakia (squamous metaplasia). Explain. Characteristic appearance
squamous metaplasia. White patch. Characteristic corderoy appearance. Benign in ureter, but may be malignant in bladder.
Malacoplakia
Multiple flat defects. Inflammatory condition a/w chronic UTI. Usually in middle aged women. Multiple flat filling defects, usually in distal ureter.
Ureteral TB
Multifocal ureteral stenosis (especially if in presence of renal TB (parenchymal calcification), or bladder TB (small capacity bladder w/ thickened wall)).
Ddx for ureteral filling defect
Ureteral malignancy. Calculus. Blood clot. Malacoplakea. Leukoplakia. Infectous debris. Sloughed renal papilla, benign ureteral mass.
UPJ obstruction causes
Congenital aperistaltic segment of ureter, high insertion of ureter on renal pelvis, or crossing vessels causing extrinsic compression.
Ddx Bilateral, Entire ureteral dilatation without ureteral obstruction? (4)
Bladder outlet obstruction. Prune-belly. Diabetes insipidus/Polydypsia. Primary megaureter.
Ddx Unilateral, entire ureteral dilatation without ureteral obstruction? (3)
Vesicoureteral reflex (grades II-IV). Ectopic ureter inserting below bladder. Bacterial infection.
Ddx Ureteral dilatation of distal segment only without ureteral obstruction? (2)
Primary megaureter. Vesicoureteral reflux (grade I).
Ureteral dilatation of proximal segment only without ureteral obstruction? (3)
Retrocaval or retroiliac ureter. Enlarged uterus. Postpartum ectasia.
Inflammatory bowel disease causes of ureteral narrowing?
Regional enteritis. Diverticulitis. Appendicitis.
Gynecologic causes of ureteral narrowing?
Endometriosis.
Traumatic causes of ureteral narrowing?
Stone passage. Iatrogenic. Mechanical stone extraction. Ureterolithotomy. Radiation therapy.
Bladder trauma evaluation
CT cystogram (350ml of 1:10 dilute contrast). Male patients w/ bladder injury may have uretheral injury. If there is blood at uretheral meatus or gross hematuria, a retrograde uretherogram should be performed prior to foley placement. If RUG shows injury, a suprapubic catheter is placed.
Bladder injury classification (2)
extraperitoneal (2X more common), or intraperitoneal
Extraperitoneal bladder rupture. Describe rupture. Mechanism. Pathognomonic finding, treatment.
Rupture of bladder outside of peritoneal space. a/w pelivc fractures causing pierce of bladder. Molar tooth sign of unverted U appearance of extravasated contrast in extraperitoneal space of Retzius. Conservative management (place foley)
Intraperitoneal bladder rupture. Describe rupture. Mechanism. Pathognomonic finding, treatment.
Disruption of bladder dome and peritoneum, causing extravasation into peritoneal apace. Mechanism of rupture usually due to pressure burst. Pathognomonic finding on CT cystogram is intraperitoneal contrast b/w bowel loops. Treated surgically.
Male Urethera segments (2 posterior and 2 anterior)
Posterior: Prostatic, membranous. Anterior: bulbous, penile.
Prostatic urethera. Lining. 2 structures
Transitional epithelium. Verumontanum, prostati utricle
Verumontanum
ridge of smooth muscle in posterior portion of prostatic urethra. Site of paired ejaculatory duct orifices. Site of obstruction in Posterior uretheral valves.
Prostatic utricle
Mullerian duct derivative. Blind ending male homologue of uterus/vagina. Located at verumontanum
Membranous urethra
Shortest, least mobile sgment. Contained w/in the urogenital diaphragm, which contains the external urethral sphincter and paired Cowper’s glands.
Bulbous urethra. Which gland drains here, which stricture goes here?
Site of Cowper’s gland drainage. Site of gonoccal stricture
Penile urethra. Lining. Name of distal portion. Glands. Which stricture?
Squamous epithelium. Distal dilatation is fossa navicularis. Glands of Littre (may get inflammed in urethritis.). Iatrogenic stricture.
Imaging options for male urethra and their uses (2)
RUG (good for anterior urethra): evaluation of stricture or after trauma. Fossa navicularis injected. VCUG (Good for posterior urethra): evaluation of bladder and voiding function.
Male Uretheral stricture types
from STI’s (gonorrhea) in bulbous urethra. Can lead to periuretheral abscess which result in urethroperineal fistula. Post-traumatic Saddle injury can cause stricture in bulbous urethra. Iatrogenic injury may be in penile urethra, at penile-scrotal junction.
5 types of male uretheral injury. Which is most common
Type III; disruption of urogenital diaphragm and rupture of the bulbomembranous urethra. Contrast extravasates into pelvis and out in perineum.
Female gland that is analagous to prostate
Paraurethral glands of skene.
Female Urethra epithelial lining
Proximal 1/3 is transitional epithelium. Distal is stratified squamous epithelium.
Female urethral diverticula. Clinical presentation. Origin. Complications
Postvoid dribbling, urethral pain. Arise from glandular dilatation caused by inflammation and chronic infection of paraurethral glands of Skene. Complications include calculi and, rarely, adenocarcinoma.
