Michael P. Federle, MDAssociate Chair for Education
Department of Radiology
Stanford University
Focal Lesions in the Cirrhotic Liver
Focal Lesions in the Cirrhotic Liver
• Cysts, hemangiomas, focal fat, confluent fibrosis– Can usually be diagnosed accurately
• Hemangiomas shrink and become sclerosed in cirrhotic liver– Often not identified in advanced cirrhosis
• Focal fat– Key is out-of-phase MR (focal sign dropout)
Brancatelli et al. Radiology 2001; 219: 69-74
RN
NECT Enhancement
Cysts Hypodense No
RN Hyperdense Minimal
Cysts + Regenerative Nodules (RN)
Cavernous Hemangioma
• Large ones have typical appearance– Very intense on T2WI– Nodular peripheral enhancement
• Smaller (“capillary”) hemangiomas– May enhance homogeneously– Can be confused with HCC– Key is remaining isodense with vessels
2 years later
Only found a “scar” in explant
Hemangioma in Cirrhotic Liver
• Shrinks to Fibrotic Scar
HCC?
No! Cavernous Hemangioma
• Isodense to vessels
Focal Confluent Fibrosis
• Present in ~ 30% of advanced cirrhosis– > 50% of PSC
• Most common in anterior + medial segments– Usually wedge-shaped lesion
• 80% have focal volume loss– Capsular retraction, crowded vessels
• Low density on NCCT– Delayed persistent enhancement
• High intensity on T2 – MR– Can simulate tumor
Ohtomo et al. Radiology 1993; 188: 31-35Krinsky et al. Radiology 2001; 219: 445-454
Confluent Hepatic Fibrosis(Focal Confluent Fibrosis)
Federle: DI: Abdomen
• Present in ~ 30% of advanced cirrhosis– > 50% of PSC
• Most common in anterior + medial segments– Usually wedge-shaped lesion
• 80% have focal volume loss– Capsular retraction, crowded
vessels• Low density on NCCT
– Delayed persistent enhancement
• High intensity on T2 – MR– Can simulate tumor
Focal Confluent Fibrosis
Note delayed enhancement
Confluent Hepatic Fibrosis
NC T1WI
HAPdelayed
MRI Confluent Hepatic Fibrosis
T1 WI
T1 PVP
Confluent Hepatic Fibrosis
T2 WI
Peripheral Wedge-shaped Lesion• May appear central + round on axial section• Examples:• Focal confluent fibrosis• THADs• AP shunts
Focal Lesions in the Cirrhotic Liver
• Regenerative nodules (RN)
• Dysplastic nodules
• Hepatocellular carcinoma (HCC)
Evolution of (some) Cirrhotic Nodules(Sakamoto hypothesis, 1991)
Regenerative Nodule
High Grade Dysplastic Nodule
Low Grade Dysplastic Nodule
Well-Differentiated HCC
Overt HCC (Moderately/Poorly Differentiated)
Regenerating Nodules
• Usually too small to detect by imaging– May be surrounded by fibrotic septa– May contain iron, copper
• Siderotic nodules– Hyperdense on NCCT, disappear on HAP & PVP– Hypointense on T2 MR, “bloom” on GRE
• Larger or vascular/enhancing RN– Can not be distinguished from dysplastic nodule or
HCC
Regenerating Nodules
NCCT
HAP
PVP
GRE
Cirrhotic Nodules• visible only on NCCT & GRE
T1 WI
T2 WI
Best seen on T2 WI(hypointense, multiple)
Regenerating Nodules
NCCT
HAP
PVP
Regenerating Nodules • hyperdense only on NECT
Regenerating Nodules • Importance of NCCT imaging• Don’t call “hypervasc. HCC”
48 y/o man with cirrhosisRegenerating Nodules
Cavernous Hemangiomas
48 y/o man with cirrhosis
Also has HCC
Must characterize lesions on all phases of CT or MR
Dysplastic Nodules
• “Adenomatous hyperplasia” (old term)• Are premalignant• Rarely diagnosed by US or CT• MR – iso to hyperintense on T1
– Hypo on T2 (opposite of HCC)– Should not enhance much on HAP– Diagnosed correctly 5 – 15% of cases
Krinsky et al. Radiology 2001; 219: 445-454
Dodd et al. AJR 1999; 173: 1185 - 1192
Dysplastic Nodules
T1WI T2WI
Hyper on T1Hypo on T2(opposite of HCC)
Focal NoduleLargeHyper on NECTMinimal vascularity
NECT
HAP
PVP
Focal NoduleBright on T1WINo signal loss on OOP(= not focal fat)Dark on T2 WIMinimal Vascularity
T2WI
T1WI-IP T1WI-OOP
Dysplastic Nodule
HAP
PVP
Delayed
Focal Nodule (same patient)Hypoechoic massUS-guided BxConfirmed dysplastic nodule
Courtesy: Mitch Tublin MDUPMC
Hepatocellular Carcinoma (HCC)
• Heterogeneously hypervascular mass
• Washes out on delayed phase
• Invades veins (portal > hepatic)
Federle: DI: Abdomen
HCC - Helical CT
• Main imaging tool in most institutions• Must be multiphasic
– Arterial phase ~ 25 – 35 seconds• Dual arterial, or test bolus is ideal
– Portal venous ~ 60 – 70 seconds– Noncontrast
• Very helpful for RNs, cysts– Delayed or equilibrium
• Useful (but hard to justify 4 phase imaging)• Rapid injection (4 or 5 ml/sec); large volume
– (2 ml/kg; > 150 ml)
HCC - Helical CT
• Allows detection and characterization of most masses > 2 cm diameter
• Accurately reflects morphology and hemodynamics of tumor– Small, well differentiated HCC
• Still have portal venous supply• Often hypo – to isodense on NC + HAP• Hypodense on PVP
– Capsule, fat common in well-differentiated– Most HCC (Best seen as hyperdense on HAP)
HCC within Dysplastic Nodule• “nodule-in-nodule” pattern
(each component has typical features)
NC PVP
Typical HCC• screening CT• chronic Hep C• isodense on NC + PVP
HAP HAP
Simplified Approach to Liver Hemodynamics
increased dysplasia = more arterial, less portal
RN Mod-diffHCC
0
20
40
60
80
100
Normal DysplasticNodule
Well-diffHCC
%
% arterial supply
% venous supply
HCC moderately differentiated• best on HAP• “washes out” on PVP
NC
HAP
PVP
HCC - only or best seen on HAP
HCC with capsuleNC
HAP
PVP
HCC well-differentiated• best on PVP
HAP
PVP
HCC Mod Differentiated• Best on HAP
PVPHAP
Small HCC• only seen on HAP & MR
T1 NC
T1 PVP T2 WI
SmallHCCT1 HAP
HCC• small tumor• PV invasion
Tumor Thrombus:•Contiguity w tumor•Expansion of lumen•Enhancing thrombus
NECT
NECT
HAP
PVP
HCC: Other FeaturesFocal fatCalcifications
Lesion with Focal fat in cirrhotic liver= HCC
= not seen (isodense, isointense)
= hyperdense (-intense) to liver
= hypointense (-intense) to liver
Regenerative
Nodule
Dysplastic
Nodule
Well-diff
HCC
Mod-diff
HCC
PVPHAPT1 T2DelayPVPHAPNC
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CT MR
Nodular Lesions in Cirrhosis
HCC - Helical CT Accuracy
• Good for large tumors• Challenging in screening population
(asymptomatic, normal tumor markers)• We miss (false + and neg) small HCCs (<2cm)
frequently• However, we usually (> 95%, UPMC data)
accurately guide Rx – Decision for follow-up, ablation, TACE,
transplantation
• Multidetector CT and dual arterial phase imaging
• Sensitivity (86%), positive pred value (92%)– Mean size of HCC (22 mm)
• Much better results than other reports
Murakami et al. Radiology 2001; 218: 763-767
HCC- Helical CT Accuracy
HCC- MR Accuracy
• Variable intensity of HCC on T1 MR– 35% hyper -, 25% iso-, 40 % hypo– Hyperintense often well-differentiated,
contain fat• Almost always hyperintense on T2 MR• Must have multiphasic study after bolus of
Gd-DTPA– Most HCC are hypervascular/intense on
HAP
HCC- MR Accuracy
• Best studies with good reference standard (OLT, explantation) in screening population– Detect HCC in 50 – 65% of patients– Detect 35 – 50% of HCC tumors– Miss many tumors 20 mm– Hard to distinguish some RNs and
dysplastic nodules
Krinsky et al. Radiology 2001; 219: 445-454
HCC- Helical CT Pitfalls
• THAD (transient hep. attenuation differences)– Small peripheral wedge-shaped
• Ignore, usually due to AP shunt or aberrant veins
• Larger segmental or lobar– Often due to tumor occlusion of portal vein
• Arterioportal shunt – Common in cirrhosis– Usually benign if small, peripheral, non-spherical,
isodense on PVP, visible vessels into + out
PVP
HAP
PVP
Lobar “THAD”• HCC obstructing RPV
AP Shunt• no tumor• resolved spontaneously
AP Shunt• ? Post-biopsy• visible vessels
AP Shunt• spontaneous
AP Shunts + Hemangioma • Shunts disappeared
• Hemangioma stable 3 yrs
AP Shunt in CirrhosisEarly draining vein
Small AP shunts are common, often resolveDon’t be too aggressive with Dx or Rx
HCC- Helical CT vs MR
• Comparable performance• MR preference
– Contrast allergy– Known steatosis
• CT preference– Ascites, unstable, tachypneic patient
• Both are evolving and improving (but often performed/interpreted poorly)
• Pitt Experience with 430 transplant recipients– Excluding 2 patients with HCC + markedly
AFP– No significant difference in serum AFP in
HCC, non-HCC groups– AFP often normal in small HCC– AFP often elevated in flare of hepatitis
Peterson et al. Radiology 2000; 217: 743-749
Tumor Markers for HCC
Screening Recommendation for Known Cirrhosis
• AFP and PIVKA II – every 3 months• Ultrasonography – every 3 or 4 months• CT or MR – every 12 months• (for chronic hepatitis without cirrhosis,
extend intervals)• (for high clinical suspicion or indeterminate
lesion, shorten interval)
Summary
• US, CT, MR all useful in evaluation of cirrhosis
• Large and symptomatic HCCs are easily detected and staged
• Small HCCs in a screening population are more challenging– Some overlap in appearance of regenerative
+ dysplastic nodules + HCC
Summary
• Optimal CT + MR techniques are key
– Must include multiple phases, rapid bolus contrast administration
• Image-guided Bx and angiography often necessary