Kidneys Flashcards
What are the different phases and timing on a renal mass protocol CT
Pre-contrast.
NephrographicPhase which is 10 second delay.
Pyelographic phase Which is approximately 15 minute delay
On contrast enhanced CT scan what is considered no enhancement, equivocal enhancement and definite enhancement?
An increaseOf less than 10 Hounsfield units is no enhancement. An increase of 10 to 19 Hounsfield units is equivocal. Greater than 20 is definite.
On MRI, what is considered no Enhancement, equivocal enhancement and definite enhancement?
For MRI it is always done as a percentage increase.
Increasing by less than 15% is no enhancement. Increasing by 15 to 19% is equivocal enhancement. Increasing by greater than or equal to 20% is definite enhancement.
For a lesion to be considered too small to characterize how must the lesion diameter compared to the slice thickness?
Only lesions which are less than two timesThe slice thickness are considered too small to characterize. For instance if the slice thickness is 3 mm, then only lesions 5 mm or less are too small to characterize.
What are wrist factors for the development of renal cell carcinoma?
Smoking, acquired cystic kidney disease, VHL, tuberous sclerosis
What lesion within the kidney would have predominately macroscopic fatWith a few soft tissue components which enhance an arterial phase imaging?
Renal Angiomyolipoma
- should never contain calcification
4% of AML’s do not have macroscopic fat. These will appear as a Hyperdense enhancing mass. They may be distinguished from clear-cell renal cell carcinoma by having low T2 signal. However, this T2 hypointensity is nonspecific and may also represent aPapillary RCC. AMLs would typically enhance more avidly than a papillary RCC
What imaging features on CT are suggestive of Oncocytoma
Homogeneous enhancement w central scar (hyper dense on pre and lack on enhancement post)
Bilateral renal AMLs w Numerous renal cyst’s
Tuberous sclerosis
