5 - Imaging Flashcards
Imaging types?
US Intravenous pyelogram CT MRI Voiding cystourethrography
why we like US?
Simple
Non-invasive
Cheap
Safe
US can ID?
Size and symmetry of kidneys
- <9cm in adult = sig irreversible disease
- size difference - unilateral disease
Thickness and echogenicity of renal cortex, medulla, pyramids
Distended urinary collecting system
Normal kidney? (US)
Less dense than liver
9(ish) cm
Can distinguish cortex from medulla
Kidney disease (US)
More dense than liver
Small (<7cm)
Cannot distinguish cortex from medulla
US is 1st choice for?
Discover various degrees of hydronephrosis
US is useful for
Obstruciton Cystic disease Bladder tumor Characterize masses (solid/cystic) GU screening (preg pts) Localized kiendy biops Post-void residual volume Congenital abnormalities
More “exciting” US of bladder?
Transrectal US (TRUS)
- prostate
- guide biopsy
Color doppler
- flow eval
- vascularity of prostate tumor
- acute testicular pain (torsion vs epididymitis)
IVP (intravenous pyelogram)
Aka IVU - intravenous urogram or excretory urography
Contrast injection
IVP is contraindicated in pts w?
H risk of ARF
CKD
Multiple myeloma
IVP good for?
– pelvicaliceal system
– renal size & shape
– renal stones (typically done now w/ helical CT)
Particularly good for:
– medullary sponge kidney
– papillary necrosis
– hydronephrosis
Before IVP?
Serum creatine (make sure its <2mg/dL)
Alternate is US
CTU?
CT urogram
- combonitation of IVP and abdominal CT
CTU is preferred radiograph for?
for upper GU tract evaluation:
• Hematuria
• Renal masses
• Stones
RUG?
Retrograde urethrogram
- suspected urethral trauma
Get a RUG if?
− Inability to void
− Blood at urethral meatus
− Perineal ecchymosis
− “High-riding” prostate
RUG technique?
• Inject contrast into urethra toward bladder • If urethra is normal: insert catheter into bladder • If urethra is NOT normal: No catheter insertion − Instead: suprapubic catheter
Cystogram?
Contrast study specifically for bladder eval
Cystogram procedure?
– Bladder is catheterized – Urine is drained – Inject contrast into bladder (~400 cc of contrast to completely fill) – Images are obtained – Oblique view is also needed to see entire length of urethra
VCUG?
Voiding cystourethrogram
Preferred method for urinary reflux eval
Who gets a VCUG?
Any child who presents w/
UTI prior to toilet training
– reflux results in recurrent
infection → significant,
scarring/narrowing of
ureters
VCUG process?
• Catheter inserted into urethra • Contrast instilled into bladder – Fluoroscopy imaging → visualization of lower GU tract → eval for reflux into ureter(s) or extravasation of contrast • When bladder is full, catheter removed • Imaging continued while patient voids
Non-contract helical CT is used for?
Detect renal stones (95% sensitive 98% specific) in pts w acute flank pain
CT has a definitive role in?
Definitive role in staging renal neoplasms
– For renal mass work-ups
• Obtain with & without contrast & compare images
• Enhancing renal masses are often malignant
CT angiogram offers?
Increasing utility in diagnosis of renovascular HTN due to renal artery stenosis
MRI easily?
Distinguishes renal cortex vrom medulla
MRI is good for?
Loss of corticomedullary function – Glomerulonephritis – Hydronephrosis – Renal vascular occlusion – Renal failure
Also - stage renal cell carcinoma
Also - renal mass eval (if CT is contraindicated)
MR angiography?
MRI study of blood vessels
- w/ w/o contrast
MRA and renal artery stenosis?
Nearly 100% sensitive
& 96-98% specific for
diagnosis of renal
artery stenosis
Advantages/Disadvantages of MRA?
Less costly & invasive than catheter angiography, but images not quite as clear – Also: potential for renal injury due to gadolinium contrast
Gold standard for renal artery stenosis?
Renal arteriogram
Other options for imaging?
– Prostascint scan
• Eval of patients already diagnosed w/ prostate cancer – for
staging…used along w/ MRI
– Bone scan
• Bone metastases evaluation – Renal scan (renography)
• Quantifies renal function
• Assesses renal blood flow – Captopril scan used to diagnose
– Renal Cell Carcinoma, Prostate Cancer
renovascular hypertension • Identifies presence of renal obstruction
Why does a kidney with stones stop working?
Because it’s between a rock and a hard place
