Genitourinary Flashcards
Do AMLs require followup?
If they are NOT part of a genetic syndrome and measure <2cm then they don’t require followup
AMLs >4cm have 85% of haemorrhage
(Haemorrhage into AML is known as Wunderlich Syndrome)
Exophytic lesions extending into perirenal fat are difficult to accurately measure and require CT
Renal cell carcinoma staging
What separates T1 and T2?
3 causes of renal artery stenosis
1. Atherosclerosis
2. Fibromuscular dysplasia - classically young women. Renal artery has ‘string of beads’ appearance in mid and distal portion. Treatment is angioplasty
3. Other - Takayasu/Beurgers/Neurofibromatosis
What is medullar sponge kidney?
What conditions are assocaited with it?
What is typical appearance on excretory nephrogram?
Dilatation of intramedullar collecting ducts. This causes urinary stasis and promotes stone formation in form of medullar nephrocalcinosis.
- can be unilateral
- can have recurrent UTIs
On excretory nephrogram - contrast within dilated tubules produces **a striated paintbrush appearance***
Causes of medullary vs cortical nephrocalcinosis?
Adrenal adenomas
What HU diagnoses of adrenal adenoma?
Diagnosis of adrenal adenoma
- HU <18
- HU <37 on a delayed scan
- 60% absolute washout
- 40% relative washout
Absolute washout
A dedicated adrenal washout CT protocol consists of a non-contrast, a contrast -enhanced scan with a delay of 60-90 sec and a delayed scan at 15 minutes.
The ROI should encompass at least 2/3 of the lesion to ensure a representable assessment.
Absolute enhancement wash out ⩾ 60% is proof of an adenoma [5,6,8].
Relative washout
If an adrenal lesion is discovered on an enhanced scan while the patient is still on the table, then a second scan of the adrenals at 15 minutes after contrast injection can be made and the relative washout can be calculated.
Relative enhancement wash out ⩾ 40% is proof of an adenoma [5,6,8].
Adrenal washout pitfalls
Important exceptions to the washout rule are caused by tumors that show absolute and relative washout percentages within the adenoma-range, in decreasing order of occurence:
Adrenal metastases from hypervascular primary tumors like RCC and HCC [17]
Pheochromocytomas
Adrenocortical carcinomas
Adrenal lesions under 1cm do NOT require followup
What is best nucleur test for demonstrating urine leaks?
DTPA
What are the characteristics of Phaeochromocytoma?
10% are:
- bilateral
- asymmetric
- contain calcification
- extra-adrena;
Have variable appearance on CT but have strong enhancement
MRI: Low T1, High T2
What US signs may be seen for renal vein thrombosis?
Spectral inversion of diastole on arterial doppler
Restrictive index is increased <0.7, however this is non-specific as also can be elevated in Renal artery stenosis
What is Bosniak Classification for renal cysts?
What is most common primary tumour to metastasize to adrenals?
Lung
followed by Breast, Colon, Stomach
Name 5 causes of medullary nephrocalcinosis?
- Hyperparathyroidism
- Renal tubular acidosis
- Medulllary Sponge Kidney
- Sarcoid
- Renal papillary necrosis
NOT Marfans
What Nucleur test is used to assess for PUJ obstruction?
Is it nephrotoxic?
Tc99m MAG3
- MAG3 has high excretion rate
- Gives overview of renal blood flow
Normal kidney will show initial increase in activity over 2mins followed by decline as it washes out
(in an obstructed kidney - activity will remain high)
MAG3 is safe for use in renal failure
What Nucleur study can be used to assess eGFR?
DTPA
Dynamic study
- DTPA is cleared only by glomeruli
- In a normal kidney the activity level peaks sharply followed by a decline which is initially rapid and then tapers off.
DTPA is NOT a good agent for patients with renal failure
What Nucleur test can be used to assess renal cortex for scarring etc?
DMSA
Static scan
Image once at 2 hours
Used to assess renal cortex in investigation of scars post pyelonephritis
What is an Oncoytoma and what does it look like?
Benign renal tumour
Present at any age
Can be very large
-Peripheral high attenuation
-Central low attenuation on CT
Spoke wheel appearance
What cause xanthgranulomatous pyelonephritis?
Results from chronic pyelonephritis and results in non functioning kidney
Caused by Proteus therefore staghorn calculi can be seen
Can give ‘bears paw’ appearance - dilated calyces filled with debris and xanthoma
What are the signs of renal TB?
‘Infundibular stenosis resulting in calyceal clubbing’
‘Moth eaten calyces leading to erosion of papillae’
Other appearances of late TB = shrunken kidney with dystrophic calcifications affecting whole kidney
Are adrenal lesions more suspicious in patients with malignancy?
Yes
If they are >3cm there is high change of malignancy
Signs of renal artery stenosis?
Leukaemia summary
Types of RCC summary
