Liver HCC, hemangioma, and RCC Flashcards
Liver hepatocellular carcinoma
Early, smaller HCC nodes receives most of its blood supply from branches of the hepatic artery, accounting for its characteristic enhancement pattern: Flash filling.
Early arterial enhancement and rapid washout, only visibly enhanced in the arterial phase, and will return to non-enhanced appearance while the portal vessels are still enhanced.
Small foci of HCC may be seen within a regenerative liver nodule, as foci of arterial enhancement (nodule-in-nodule appearance)
Large HCCs will be inhomogenous, and have areas of cystic necrosis or hemorrhage, may have rim enhancement or late contrast retention around the borders.
Focal nodular hyperplasia
In colloid scintigraphy,
These nodules will be uptake excessive tracer, but lack normal biliary tracts to secrete it, trapping the tracer which is the slowly redispersed back to the rest of the liver and secreted.
This can in some cases be mimiced by very well differentiated HCC.
Liver hemangioma
Hypodense, well circumscried lesions on CT.
Strong contrast enhancing, with filling that matches the blood phases, can begin nodular/peripherally, but the intensity of the filling always matches the same as the large liver vessels.
HypERechoic by US.
Timing of the phases
Arterial phase 20-30s after injection
Portal/Venous phase 60-70s after injection.
Non-enhanced CT (NECT)
Helpful in detecting calcifications, fat in tumors, fat-stranding as seen in inflammation like appendicitis, diverticulitis, omental infarction etc.
Early arterial phase - 15-20 sec p.i. or immediately after bolustracking
This is the phase when the contrast is still in the arteries and has not enhanced the organs and other soft tissues.
Late arterial phase - 35-40 sec p.i. or 15-20 sec after bolustracking. Sometimes also called “arterial phase” or “early venous portal phase”, because some enhancement of the portal vein can be seen. All structures that get their bloodsupply from the arteries will show optimal enhancement.
Hepatic or late portal phase - 70-80 sec p.i. or 50-60 sec after bolustracking. Although hepatic phase is the most accurate term, most people use the term “late portal phase”. In this phase the liver parenchyma enhances through bloodsupply by the portal vein and you should see already some enhancement of the hepatic veins.
Nephrogenic phase - 100 sec p.i. or 80 sec after bolustracking. This is when all of the renal parenchyma including the medulla enhances. Only in this phase you will be able to detect small renal cell carcinomas.
Delayed phase - 6-10 minutes p.i. or 6-10 minutes after bolustracking. Sometimes called “wash out phase” or “equilibrium phase”. There is wash out of contrast in all abdominal structures except for fibrotic tissue, because fibrotic tissue has a poor late wash out and will become relatively dense compared to normal tissue. This is comparable to late enhancement of infarcted scar tissue in cardiac MRI.
Renal cystic masses
Bosniak scale:
1: simple cyst. small rounded clear wall. 0% malignant
2: minimally complex,
a few then septa or microcalcifications.
Non-enhancing. 0%
2F: minimally complex,
a few septa, which may be slightly thickened with nodular or thick calcifications.
very minimal/percieved enhancement of the septa
cyst above 3cm in diameter
3: indeterminate
Multiple, Thick, nodular septa, with measurable enhancement.
Septa are hyperdense on CT
Should be excised or radiated if surgery intolerable
55% malignant
4: clear malignant
Solid hyperdense mass with large cystic and necrotic components, large hyperdense septa.
100% malignant.
nephrectomy.
Renal cell carcinoma.
variable appearance, multiple different types: clear cell rcc paipllary rcc chromophobe collecting duct rcc
Usually have heterogenous appearance, with solid components, as well as necrotic, hemorrhagic regions
Clear cell RCC: hyperintense mass
Papillary RCC: hypointense mass
They usually do not enhance as much as the surrounding kidney.
