TPCT - Triphasic CT Scan - Liver

Triphasic CT (TPCT) Scan of the liver is essential in view of the dual blood supply of the liver. TPCT allows characterisaiton of all liver lesions and close to pathological correlaiton by non invasive imaging alone. Additionally providing segmental vascular analysis as a surgicical guide.

1. TPCT Liver
Dr. Pankaj Saini
Sr. Consultant
Radiology

2. TPCT Liver
Technique
Indications
Demographics
Lesion Characterization
Volumetry

3. TPCT Liver
Technique
Pre-contrast – Deferred in follow up / Metastasis,
Arterial phase of contrast enhancement
Portal phase of contrast enhancement
Veinous Phase – Equilibrium
abdominal CT is completed to iliac crest level.
Hemangioma is suspected – additional delayed images
to assess for filling in of hemangioma.

4. Technique
Iodinated Contrast
Nonionic
Serum Creatinine
eGFR – Estimated Glomurelar Filtration rate
Contrast Dose – 2 ml / kg maximum of 150ml
Rate of Injection – 4 ml / sec at 300 psi
IV cannula – 18 to 20 guage
Multi Slice CT – Reduce the contrast Dose
Arterial Phase – Timing and Rate
Veinous Phase – Total Iodine Dose

5. Technique
Timing of scan
Arterial – bolus tracking 18 to 25 sec
Portal – 45 sec
Veinous – 65 sec
Collimation – Spatial resolution / Image noise
Pitch – 1.25 : 1
Table speed of 15 mm / Rotation
Reconstruction interval – 1.5 overlap 0.75
Kvp / mAs – 120 / 225
FOV 350
High Quality, Large volume, Reasonable radiation dose
to Obtain 3D Multiplanar images in single breath hold.

6. Pitch & Collimation
Relatively narrow collimation
Limited by Image noise & Length of coverage
Overcome by Pitch

7. Dual Blood Supply
Normal parenchyma is supplied for 80% by the portal vein and
only for 20% by the hepatic artery,
normal parenchyma will enhance maximally in the hepatic veinous phase
at 65-75 sec p.i. and only a little bit in the late arterial phase at 18 - 35 sec p.i..

8. Lesion Characterization
All liver tumors however get 100% of their
blood supply from the hepatic artery.
Hypervascular tumor will be best seen
in the late arterial phase.
Hypovascular liver tumor enhances poorly in the
late arterial phase, difficult to differentiate from
the poorly enhancing liver parenchyma
Best seen when the surrounding tissue enhances,
i.e. in the veinous phase at 65-75 sec p.i.

9. Lesion Characterization
x
x
x

10. Arterial phase at 25sec
Hypervascular lesions like
HCC (Hepatocellular Carcinoma)
FNH (Focal Nodular Hyperplasia)
Adenoma
Hemangioma
will enhance optimally

Normal parenchyma shows only minimal enhancement.
Lesion Characterization

11. HCC
Solitary, Multicentric, Diffuse
Calcification – 7%, Isodense on NCCT and Equilibrium phase
Arterial enhancement and Early washout
Angioinvasive

12. Adenoma
Solitary lesion
Absence of bile ducts
& kupffer cells
Female predominance
Age 20- 40 yrs
H/O – OCP,
Anabolic steroids
Thin capsule
Vessel in periphery

13. FNH
Asymptomatic
? Congenital vascular
malformation
Female predominance
Age 20 – 50 Yrs
Central avascular scar
Hypodense on NCCT

14. Hemangioma

15. Portal phase at 45 sec p.i.
Hypovascular lesions like
Metastases
Cysts &
Abscesses
Lesion Characterization

16. Metastases
Hypovascular
Metastases
Colon
Hypervascular
Metastases
Breast, Sarcomas,
Neuroendocrine
tumors,
RCC & Melanoma
Calcified
Mucinous GI tract
Ovarian

17. Abscess
Non homogenous
Reduced density
Septal / irregular
enhancement
Peripheral / wall
enhancement

18. Veinous phase at 65 sec p.i.
Fibrotic lesions like
Cholangiocarcinoma
Fibrotic metastases
hold the contrast much longer than normal parenchyma.
Lesion Characterization

19. Cholangiocarcinoma
High recurrence rate (77%) metastases recurrence (60%)
Absolute contraindication to transplant
Predisposition seen with primary sclerosing cholangitis
Early peripheral enhancement with peripheral delayed filling
Mass forming intrahepatic lesion with ductal invasion

20. Lesion Characterization
Pre contrast Arterial PhaseVenous phase Delayed
HCC Low attenuation
Homogenous
enhancement
Washout Isodense
Adenoma Low attenuation
Homogenous
enhancement 85%
Iso or hypodense
Iso or
hypodense
FNH
Iso/Low
attenuation
Homogenous
enhancement
Hypodense Isodense
Haemangioma Low attenuationPeripheral puddlesCentripetal fillingComplete fill in
CholangiocarcinomaLow attenuationIso attenuationEnhancement Isodense
Hypervascular
Metastases
Low attenuation
Homogenous
enhancement
Hypodense
Hypovascular
Metastases
Low attenuation Hypodense Hypodense
Cyst Low attenuationNo enhancement
Abscess Low attenuation
may have
irregular margins
Transient regional
enhancement
Wall
enhancement

21. Recipient
CLD
MELD Score (Model for End Stage Liver
Disease)
HCC / Extent / Milan / UCSF Criteria /
TNM
Angioinvasion / Periportal lymphnode
Portal / IVC Thrombus
Donor
LAI (Liver Attenuation Index) – Steatosis
Liver Angiography
Liver Volumetry
Biliary Duct anatomy - Cholangiography
Liver Transplant Imaging

22. Liver Transplant Imaging
MELD Score (Model for End-Stage Liver Disease)
TIPS – Transjugular Intrahepatic Portosystemic Shunting
3 month mortality
Prognostication Prioritize Liver transplant
Serum bilirubin, Serum creatinine and PTINR
Dialysed 2 x 7 days – Sr. Cr. 4.0
Value of 1 of any unit below one
MELD = 3.78×ln[S Bil. (mg/dL)] + 11.2×ln[INR] + 9.57×ln[S Cr. (mg/dL)] + 6.43
3 month mortality in hospitalized patients
≥ 40 – > 70% mortality
30 – 39 – 52.6 %
20 – 29 – 19.6%
10 – 19 6.0%
< 9 – 1.9% mortality
Mayo Clinic by Dr. Patrick Kamath
Mayo End-stage Liver Disease Score

23. Milan criteria
Defined as 1tumor ≤5cm;
   
or ≤3 tumors with each tumor ≤3cm
 
UC.SF criteria
Defined as 1tumor ≤6.5cm
   
or ≤3 tumors with the largest tumor diameter
≤4.5& total tumor diameter ≤8cm
   
TNM Classification
Defined as Stage 1 – 1 Tumor ≤ 1.9cm
Stage 2 – 1 Tumor 2-5cm or upto 3 each ≤3cm
Without extrahepatic metasteses
Liver Transplant Imaging

24. Segmental Anatomy
Couinaud Segmental Anatomy

25. Segmental Anatomy
Couinaud Segmental Anatomy

26. Arterial Anatomy
30 % donors may be rejected – unsuitable arterial anatomy
Right and left HA arising from CHA Type 1
Segment IV artery may be a branch of RHA or LHA
3D Volume rendered images – Digital subtraction angiography

27. Portal Vein
Main portal vein – bifurcates in Rt and Lt branch – Type A
Right branch is considered continuation of MPV
Trifurcation of protal vein – Type B require Dual anastomoses

28. Hepatic Vein
Right, Middle and Left Hepatic veins drain to IVC
Accessory vein usually in segment VIII of right lobe (6%)
Volume rendered 3D images

29. Volumetry
Manual tracing – very accurate
Automatic and Semiautomatic Segmentation
Interactive Semiautomatic
Substantially less user time 1 min / case
Manual upto 45 minutes / case
Semiautomatic 15 minute / case
IntelliSpace Portal Liver Analysis Application
Phillips

30. 9 anatomical landmarks
Liver segmental localisation
Volumes with and without vessels
Transplant segment volume calculation
Remnant volume
Volumetry

31. A – First bifurcation of Right Portal vein
B – Inferior Vena Cava
C – Right Hepatic vein
D – Middle Hepatic vein
E – Left Hepatic vein
Volumetry

32. F – Superficial ligamentum venosum
G – Deep ligamentum venosum
H – end of Left Portal vein
I – Left Liver tip
Volumetry

33. x
x
x
Automated outline of the entire liver with corrections for
false positive and false negative extractions
Manual positioning of 1
st
landmark at bifurcation of RPV
Volumetry

34. x
x
x
Volume rendered image with automated volume calculation
“Segments of Couinaud”
Transverse image after manual correction of the false
positives and false negatives
Volumetry

35. Volumetry

36. Cholangiocarcinoma
Peri hilar location
Transplant was deferred
Right segmental hepatectomy
Remnant liver volume
Volumetry

37. Segmental Anatomy
Couinaud Segmental Anatomy

38. Volumetry
Potential Donor / Surface area
Minimum 40% normal liver
volume is needed by recipient
Minimum 35% remnant liver
volume is left with donor

39. Thank You !!!