Type:
Educational Exhibit
Keywords:
Not applicable, Transplantation, Pathology, Acute, Surgery, Computer Applications-3D, Comparative studies, Nuclear medicine conventional, CT-Quantitative, CT, Paediatric, Liver, Abdomen, Abdominal Viscera
Authors:
A. Shankar, D. S. srinivas, D. S. Kalyanasundaram, D. M. S. Reddy, M. Rela; Chennai/IN
DOI:
10.26044/ecr2020/C-07172
Findings and procedure details
Baseline Contrast enhanced CT (CECT) and HIDA scans are performed at 4 weeks after an APOLT for volumetry and functional assessment respectively [5].
These are easily interpreted with the surgical technique in mind.
Post operative anatomy in a left lobe APOLT:
- An extended left hepatectomy (includes removal of Middle hepatic vein) is performed in the recipient and right lobe parenchyma drained by the right hepatic vein remains.
- Left lobe lateral segment graft is then implanted with vascular and biliary anastomoses [2]. (Figure 1)
Fig. 1: Intra- operative picture (A) ; processed maximum intensity projection (B) and volume rendered (VR) Computed Tomography image (C) of post APOLT status with standard left lobe technique; depicting smaller remnant liver- right lobe(small arrow) and larger implanted graft liver - left lateral segment( long arrow).
References: For 1(A) : Rela M, Kaliamoorthy I, Reddy MS. Current status of auxiliary partial orthotopic liver transplantation for acute liver failure. Liver transplantation: official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society. 2016;22(9):1265–74.
Vascular anastomosis :
1.Volume and enhancement pattern of native liver remnant and graft ( Figure 6)
Fig. 6: Axial CECT image (A) showing heterogeneous enhancement of graft liver in baseline CECT images. Processed MIP and VR images of remnant native liver ( B&C) and graft (C& D) with volume estimation.
2. Survey of vasculature at anastomotic sites and patency within native liver and graft ( Figure 7)
Fig. 7: 1 year post APOLT status, Axial Triphasic CECT images showing normal enhancement of native liver (A); Patent arteries ( B) ; Portal vein branches (C) and Hepatic veins (D) within remnant and graft liver.
3. Integrity of biliary anastomoses and presence of biliary radical dilation in the graft
4. Any postoperative collections
5. Routine abdominal survey including that of incision and drain sites
Post operative portal hemodynamics in APOLT for Acute liver failure :
- Portal blood flow is shared by the graft and native liver remnant; the individual volumes determined by resistance to inflow at the sinusoidal level which undergoes a series of changes in the post operative period [7].
- Initially the remnant is quite stiff acting as a bed of high resistance with consequent preferential flow diversion to the graft ensuring its optimum function.
- With recovery of hepatocytes; resistance falls allowing a proportional increase in portal flow to the native liver favouring regeneration thereby forming a positive feedback.
- The radiological correlate of these processes is initial heterogeneous enhancement of the remnant which is smaller in size in early postoperative period followed by progressive homogenization and increase both in volume and function with hepatocyte regeneration.
- After histopathological confirmation of the same at an appropriate post op interval ; initiation of immunosuppression withdrawal can be considered once relative function of ~ 50% is achieved by the remnant [2] .
Serial Imaging Protocol :
CECT and HIDA scans are performed at 6 monthly intervals to obtain an overview of the extent of native liver regeneration.
CASE DETAILS:
-
A 4 year old child with ALF secondary to fulminant hepatitis A infection received an APOLT.
- Baseline CECT image (Figure 8 ) shows a shrunken native right lobe remnant with heterogeneous enhancement.
- Left lobe graft is larger with homogeneous enhancement.
- Native and graft PV and HA branches were patent.
- No biliary dilation was seen in the graft.
- Baseline HIDA scan revealed differential function of 6 % for native remnant and 94% for the graft.
Fig. 8: Early post operative CT( A&C) and HIDA scans( B&D) for a 4 year old child who underwent APOLT for ALF. It reveals a small remnant right lobe with larger left lobe graft .At this stage,the graft contributes to major fraction( >90%) of total liver function as seen in HIDA.
References: Rela M, Kaliamoorthy I, Reddy MS. Current status of auxiliary partial orthotopic liver transplantation for acute liver failure. Liver transplantation: official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society. 2016;22(9):1265–74.
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Subsequent follow up scans ( Figure 9 ) showed an increasing trend in native remnant volume and function almost on par with the graft.
Fig. 9: 12 months post transplant CT (A) and HIDA (B) scans shows adequate native liver regeneration and function. Hence immunosuppression withdrawal was started .
References: Rela M, Kaliamoorthy I, Reddy MS. Current status of auxiliary partial orthotopic liver transplantation for acute liver failure. Liver transplantation: official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society. 2016;22(9):1265–74.
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Subsequent follow up at 30 months (after immunosuppression withdrawal )showed further interval increase in size of native liver( ~ 421 cm3) with function upto 96 %. (Figure 10)
Fig. 10: Imaging 2.5 years after transplant and complete immunosuppression withdrawal shows an atrophied left lobe graft with a regenerated native right liver contributing 96% of total liver function.
References: Rela M, Kaliamoorthy I, Reddy MS. Current status of auxiliary partial orthotopic liver transplantation for acute liver failure. Liver transplantation: official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society. 2016;22(9):1265–74.