1. Current Problems in Diagnostic Radiology
Tricky Findings in Liver Transplant Imaging: A Review of Pitfalls With Solutions 
Bhagya Sannananja, MD, Adeel R. Seyal, MD, Akshay D. Baheti, MD, Sooah Kim, MD, Chandana Lall, MD, Puneet Bhargava, MD 
Current Problems in Diagnostic Radiology 
DOI: /j.cpradiol
Copyright © 2017 Elsevier Inc. Terms and Conditions

2. Fig. 1
Fish-mouth hepatic artery anastomosis. Illustration shows stepwise surgical construction of fish-mouth hepatic artery anastomosis during orthotopic liver transplantation. This figure shows anastomosis between donor common hepatic artery-splenic artery branch point (blue line, donor side) and the gastroduodenal artery-proper hepatic artery bifurcation (blue line, recipient side). (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

3. Fig. 2
Portal vein size discrepancy. Duplex Doppler ultrasound image shows size discrepancy between anastomosed portal veins with increased turbulence around the anastomosis. This should be considered as within expected limits. Presence of hemodynamically significant stenosis can be assessed with the use of transhepatic direct portography. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

4. Fig. 3
Hepaticojejunostomy. (A) Illustration shows postsurgical anatomy after hepaticojejunostomy. There is anastomosis between the common hepatic duct and the proximal portion of jejunum. Cholecystectomy is generally performed during orthotopic liver transplant (removed gall bladder shown in the illustration). (B) Gray-scale US image shows highly echogenic foci along the bile ducts (arrow) consistent with pneumobilia, a normal finding in patients with hepaticojejunostomy. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

5. Fig. 4
Hepatic echogenicity. (A) Gray-scale US image obtained on day 1 after OLT shows heterogeneous hepatic echotexture likely due to contusion or hemorrhage in the donor liver. (B) Gray-scale US image of the same patient on day 3 after OLT shows improved hepatic echotexture.
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

6. Fig. 5
Starry-sky appearance. Grays-scale US image obtained in the early postoperative period after orthotopic liver transplant shows echogenic portal venules with decreased echogenicity of the surrounding liver parenchyma. This is due to reperfusion hepatic edema in the immediate postoperative period.
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

7. Fig. 6
Pleural effusion and perihepatic hematoma. (A) Gray-scale US image performed in immediate postoperative period after OLT shows right-sided pleural effusion (arrow), a common postoperative finding. This is usually sympathetic in nature and resolves in a few days. (B) Perihepatic hematoma. Gray-scale US image performed in early postoperative period after orthotopic liver transplant shows perihepatic echogenic fluid collection (arrow) consistent with a hematoma, a common postoperative finding.
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

8. Fig. 7
Elevated hepatic artery peak systolic velocity. (A) Duplex Doppler US image obtained on day 1 after OLT shows elevated hepatic artery peak systolic velocity (up to 439cm/s) due to anastomotic side edema and transient hyperdynamic state secondary to portal hypertension. (B) Duplex Doppler US image obtained on day 3 after OLT shows improved hepatic artery peak systolic velocity (down to 92cm/s) secondary to resolution of anastomotic edema and improvement in flow hemodynamics. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

9. Fig. 8
Elevated hepatic artery resistive index. (A) Duplex Doppler US image obtained on day 1 after orthotopic liver transplant shows elevated hepatic arterial resistive index (1.00) with poor diastolic flow and decreased visualization of the main hepatic artery (arrow). This is likely a result of increased resistance to flow secondary to hepatic arterial spasm or tissue edema. (B) Duplex Doppler US image obtained on day 3 after OLT shows improved resistive index (0.82) with improved hepatic arterial flow and better visualization of the main hepatic artery. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

10. Fig. 9
Hepatic arterial spasm. (A) Duplex Doppler US image obtained in early postoperative period after OLT shows rapid upstroke, sharp systolic peak, and reversal of flow during diastole. (B) Duplex Doppler US image performed after administration of nifedipine, a vasodilator, shows antegrade flow along the main hepatic artery. This confirms the presence of hepatic arterial vasospasm during early postoperative period. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
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11. Fig. 10
Contrast-enhanced ultrasound image showing flow in the right hepatic artery (arrow). Color Doppler ultrasound obtained on day 1 after OLT failed to demonstrate flow in the right hepatic artery. Contrast-enhanced ultrasound on the same day shows flow in the right hepatic artery, which was missed on routine Color Doppler ultrasound.
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

12. Fig. 11
Tardus parvus hepatic artery waveform. (A) Duplex Doppler US image performed on day 1 after orthotopic liver transplant shows tardus parvus waveform secondary to anastomotic site edema causing focal stenosis and dampened waveform distally. Note decreased resistive index (0.31). (B) Duplex Doppler US image obtained on day 3 shows resolution of anastomotic site edema, improved resistive index (0.74), a more rapid upstroke, and return of normal hepatic arterial waveform. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
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13. Fig. 12
Chronic hepatic artery thrombosis. (A) Duplex Doppler US image performed in the early postoperative period shows normal hepatic arterial waveform with normal peak systolic velocity (0.31m/s) and resistive index (0.75). (B) Duplex Doppler US image at 3-month follow-up shows decreased peak systolic velocity (down to 17.6cm/s) and resistive index (0.34) due to hepatic artery thrombosis. (C) Duplex Doppler US image performed at 6-month follow-up shows improved resistive index (0.46) suggesting formation of collateral vessels. Note the presence of tardus parvus waveform (arrow). (D) Hepatic artery angiogram shows multiple collateral vessels (arrow) around the thrombosed segment, thus maintaining blood flow to the distal vessels. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
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14. Fig. 13
Hepatic artery pseudoaneurysm. (A) Gray-scale ultrasound shows dilated hypoechoic area (white arrow) in the region of hepatic artery concerning for hepatic artery pseudoaneurysm. (B) Color Doppler ultrasound of the same patient reveals irregular flow pattern (black arrow) consistent with hepatic artery pseudoaneurysm. This characteristic to and fro flow inside the pseudoaneurysm is known as the ‘yin-yang’ sign. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
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15. Fig. 14
Fish-mouth hepatic artery anastomosis. (A) CT angiogram with 3D coronal reconstruction shows anatomy of fish-mouth hepatic artery anastomosis (white arrow) in a post liver transplant patient. (B) Axial CT scan image of a different patient shows dilation of hepatic artery (black arrow) consistent with pseudoaneurysm of the hepatic artery in a post liver transplant recipient.
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

16. Fig. 15
Pulsatile portal venous flow. (A) Duplex Doppler US image obtained on day 1 after orthotopic liver transplant shows pulsatile portal venous flow. This type of flow waveform is commonly encountered in congestive heart failure and in the immediate posttransplant period due to altered hemodynamics. (B) Duplex Doppler US image performed on day 3 shows normal monophasic portal venous flow due to improved hemodynamics. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

17. Fig. 16
Turbulent portal venous flow. (A) Duplex Doppler US image obtained on day 1 after orthotopic liver transplant shows turbulent flow in the main portal vein with increased velocity (up to 131cm/s) secondary to decreased portal resistance in the setting of increased splanchnic flow. (B) Duplex Doppler US image on day 3 shows improved turbulence with decreased portal venous velocity (down to 54cm/s). (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
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18. Fig. 17
To-and-fro flow in portal vein. (A and B) Duplex Doppler US images show to-and-fro flow within the left portal vein varying with respiratory motion. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
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19. Fig. 18
Hepatic venous turbulence in a post-OLT patient. (A) Duplex Doppler US image obtained on day 1 after orthotopic liver transplant shows turbulence at the hepatic vein-inferior vena cava anastomotic site secondary to edema (arrow). (B) Duplex Doppler US image performed on day 3 shows improved turbulence due to resolution of edema (arrow). (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

20. Fig. 19
Monophasic hepatic venous flow. (A) Duplex Doppler US image on first postoperative day shows monophasic flow in the middle hepatic vein secondary to anastomotic site edema causing focal area of narrowing resulting in loss of phasicity. (B) Duplex Doppler US image obtained on day 3 shows return of normal triphasic waveform in the middle hepatic vein with resolution of edema. (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions

21. Fig. 20
Positional inferior vena cava (IVC) waveform changes. (A) Duplex Doppler US image in a post-OLT patient shows monophasic waveform in middle hepatic vein in supine position owing to pressure effect of overlying transplanted liver. (B) Duplex Doppler US image obtained in left lateral decubitus position shows return of normal triphasic waveform in middle hepatic vein. (C-F) Illustration shows concept behind positional changes in IVC waveform on Duplex Doppler US images. The pressure effect of overlying transplanted liver in supine position (C and D) can cause focal stenosis and waveform changes. These changes resolve when the patient is placed in left lateral decubitus position (E and F). (Color version of figure is available online.)
Current Problems in Diagnostic Radiology DOI: ( /j.cpradiol )
Copyright © 2017 Elsevier Inc. Terms and Conditions