Imaging of the Post-operative Liver: Review of Normal Appearances and Common Complications

Transcription

1 Imaging of the Post-operative Liver: Review of Normal Appearances and Common Complications Poster No.: C-0314 Congress: ECR 2015 Type: Educational Exhibit Authors: S. Mule, A. Colosio, J. Cazejust, P. Soyer, R. Kianmanesh, C Hoeffel ; Rheims/FR, Chenay/FR, Paris/FR Keywords: Liver, CT, MR, Ultrasound-Power Doppler, Surgery, Embolism / Thrombosis, Abscess, Ischaemia / Infarction DOI: /ecr2015/C-0314 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 31

2 Learning objectives Recent technical developments have lead to a substantial increased number of potential indications for liver surgery. Morbidity and mortality rates remain high, due to increasing number of complex surgical procedures. Imaging plays a crucial role in the early identification and management of postoperative complications. The objectives of our educational exhibit are to: Be familiar with the different types of hepatic resection; Be aware of the expected postoperative imaging features; Highlight the complementary role of the various imaging techniques in the identification of postoperative complications; Be familiar with the imaging features of early and late complications. Page 2 of 31

3 Background Liver Segmentation Liver surgery mainly consists in "anatomical", segment-oriented resections, based on the intrahepatic distribution of portal branches and hepatic veins (Fig. 1). The middle hepatic vein divides the liver into right and left hemilivers. Each hemiliver is further divided by the right and left hepatic veins into sections: anterior and posterior sections (right hemiliver), and medial and lateral sections (left hemiliver). The horizontal plane containing the main portal vein branches further divides each section into cranial and caudal segments. Page 3 of 31

4 Images for this section: Fig. 1: Liver segmentation Modified from Page 4 of 31

5 Findings and procedure details 1. Liver resection Liver resection consists of: - Anatomical resections: Right or left (± extended) hepatectomy: Right hepatectomy involves excision of segments 5, 6, 7 and 8, while extended right hepatectomy involves additional excision of segment 4. Left hepatectomy involves excision of segments 2, 3 and 4; Mono-, bi- or trisegmentectomies (Fig. 2); Sectionectomies: Right anterior (segments 5-8) or posterior (segments 6-7) sectionectomy; Left medial (segment 4) or lateral (segments 2-3) sectionectomy. - Atypical, non anatomical resections (wedge resections), increasingly performed (Fig. 3). Non functional resections: increased risk of postoperative haemorrhage and biliary fistulae; May be performed for small sized, wedge peripherally based resections only. - Surgery of hepatic cysts: Depends on type, number and localization of the cysts; The different types of surgery are: fenestration in the peritoneal cavity, resection of protruding dome, or partial hepatectomy. 2. Normal postoperative imaging features In the absence of complications, postoperative liver imaging is not routinely systematically performed. Systematic follow-up examination using abdominal US or CT can somehow be performed in case of extended hepatic resection (Fig. 4). Page 5 of 31

6 After right hepatectomy, normal imaging findings include (Figs. 5-6): Section and ligation of the right portal vein at its origin; Shift of left liver towards the right with horizontalisation and posterior shift of portal vein; Rapid hypertrophy and rounded contours of the remaining liver, particularly of segments 1 and 4; Upwards displacement in the right subphrenic area of the right kidney, descending colon, and of small bowel loops. After extended right hepatectomy, similar morphological changes except for resection of segment 4 can be expected (Fig. 7). After left hepatectomy, normal imaging findings include (Fig. 8): Section and ligation of the left portal vein at its origin; Smooth and rounded enlargement of the right remaining liver; Moderate enlargement of segment 1; ± portal vein and hepatic pedicle shift to the left; ± left hepatic fossa occupied by the stomach and transverse colon. After segmentectomy (unique or multiple), fluid or fat-density area typically occupies the resection space. Morphological changes of the remaining liver are observed only in case of resection of several segments (Figs. 9-10). After atypical, non anatomical resection (wedge resection), normal imaging findings include (Fig. 11): Fluid or fat-density area occupying the resection space; Peripheral capsular retraction at the resection site; No major morphological changes of the remaining liver (small size resections). Page 6 of 31

7 After cyst fenestration, expected imaging findings include (Fig. 12): Fluid collections with irregular wall in the fenestration site; ± Fat-density area adjacent to resection margins, related to omentum filling intraparenchymal cavities (improved bile resorption). 3. Early postoperative complications Most frequent early postoperative complications are: Fluid collections (hematoma, abscess, seroma, bilioma); Vascular thromboses (portal vein, hepatic veins, hepatic artery); Biliary injuries. Suggestive symptoms include: Fever, abdominal pain, jaundice; Drop in hemoglobin level, persisting elevation of liver enzyms at D5 postoperative (PT < 50%, serum bilirubin > 50 µmol/l) Fluid collections Fluid collections are predominantly adjacent to resection margins, and correspond to seromas/ hematomas (50%), bilomas (25%), or infected collections (25%). Subphrenic collections are also frequent. Doppler US often is the first-line examination. It allows the evaluation of the size, topography, and echogenicity of the collection. The permeability and flow of the remaining portal and hepatic veins could be also studied. However, Doppler-US is limited for characterization and MDCT should be additionally performed. MDCT offers higher degrees of specificity for fluid characterization (Fig. 15), and can reveal associated complications such as venous thrombosis or abscess. MDCT Protocol should include: Unenhanced scan: hematoma? Page 7 of 31

8 Arterial phase: active bleeding? Portal phase: venous thrombosis, abscess? 3.2. Vascular thromboses Postoperative vascular thromboses include: Portal vein thrombosis: relatively rare after liver resection. Thrombosis of a segmental portal branch is more frequently observed (Fig. 16); Hepatic vein thrombosis (Fig. 17): adjacent to resection margins ++; Acute Budd-Chiari syndrome: rarely left hepatic vein kinking or torsion after right hepatectomy. More frequently, thrombosis of a remaining hepatic vein close to resection margins can be found (Fig. 18). Hepatic vein thrombosis can be incomplete or complete, and may extend to inferior vena cava (Fig. 19). Doppler US will be a useful diagnostic modality by revealing: The echogenic appearance of the vein; The absence of portal flow (in case of portal vein thrombosis); Flow demodulation in the remnant hepatic veins (in case of acute BuddChiari syndrome). MDCT and MRI can also diagnose veinous thrombotic oclusions and will show: A lack of enhancement of the obstructed vein; Perfusion abnormalities of hepatic parenchyma Biliary injuries Most frequent postoperative biliary injuries include: Biliary fistula at the resection margins: 5% after major resection. US or MDCT reveals a nonspecific fluid collection at the resection margin (Fig. 20); Injury of biliary convergence: rare ++. Suggestive clinical findings are jaundice and productive fistula. Page 8 of 31

9 3.4. Intraoperative diaphragmatic injury More rarely, intraoperative diaphragmatic injury can occur after liver resection and may be responsible for biliary fistulae (Fig. 21) or small-bowel obstruction (Fig. 22). The latter may be difficult to diagnose because of frequent postoperative ileus due to anesthetic drugs. 4. Late postoperative complication Late postoperative complications mostly consist of initial disease recurrence in patients with liver malignancies. After difficult surgery, peroperative arterial injury may cause ischemic cholangitis Disease recurrence Hepatocellular carcinoma (Fig. 23): Risk for recurrence up to 70% at 5 years; Risk increased in case of presence of a chronic liver disease; Postoperative imaging follow-up includes: Doppler-US, MDCT/ MRI, or contrast-enhanced US. Cholangiocarcinoma: Hilar or distal; High recurrence rate, mostly local recurrences; Earlier recurrences are found in case of distal cholangiocarcinoma; Postoperative follow-up includes: Doppler-US, abdominal MDCT. Liver metastases: Disease recurrence in 67%. Only intrahepatic recurrence in 50%; Repeated resection is possible; Page 9 of 31

10 Postoperative follow-up includes: Doppler-US/ abdominal MDCT/ MRI Ischemic cholangitis Ischemic cholangitis is rare. It always occurs after peroperative arterial injury. Suggestive clinical findings are unspecific and include jaundice and fever. Ischemic cholangitis can be diagnosed by MDCT (Fig. 24) but MRcholangiopancreatography (MRCP) is the diagnostic modality of choice. MRCP will reveal irregular and multiple bile duct stenoses with intrahepatic ductal dilatations (Fig. 25). Biliary abscesses or bilomas could additionally been found. Page 10 of 31

11 Images for this section: Fig. 2: Examples of monosegmentectomy and bisegmentectomy. Modified from Page 11 of 31

12 Fig. 3: An example of wedge resection of segment 7. Modified from Page 12 of 31

13 Fig. 4: Right hepatectomy for HCC developed on cirrhotic liver. Surgical staples appear as hyperechoic foci (arrows). Fluid collection on liver section (*). Page 13 of 31

14 Fig. 5: Right hepatectomy performed for metastases from colorectal cancer. Left lateral section (LLS) and segments 1 and 4 are hypertrophied. Rounded contours and angles of remaining liver as well as a right shift of remaining liver and portal vein can be observed. The resection space is occupied by a fat-density area (*) related to epiplooplasty. Fig. 6: Right hepatectomy performed for metastases from colorectal cancer. The remaining liver is hypertrophied. The resection site is occupied by ascending pylorus (*) and right colic angle (arrow). Page 14 of 31

15 Fig. 7: Extended right hepatectomy for a large HCC in the right liver (*). The left lateral section (LLS) and segment 1 are hypertrophied with rounded contours. The portal vein shifts to the right (arrow), while the ascending right kidney fills the resection site. Fig. 8: Left hepatectomy performed for metastases from colorectal cancer. The right remaining liver shows rounded hypertrophy. Look at the gastroparesis with adhesion of the stomach (arrows) to the resection site. Page 15 of 31

16 Fig. 9: Bisegmentectomy 2-3 performed for metastases from colorectal cancer. Segment 4 is enlarged (*). One can see integrity of left portal vein (arrow). Page 16 of 31

17 Fig. 10: Bisegmentectomy 5-6 for a large metastasis from colorectal cancer. The resection space is occupyied by a fat-density area (*) related to epiplooplasty. Metallic surgical clips are found along the surgical margins. Page 17 of 31

18 Fig. 11: Wedge resection at the junction of segments 5-8 for a metastasis from colorectal cancer. Look at the fluid collection in the resection site, and at the metallic surgical clips along the surgical margins. Page 18 of 31

19 Fig. 12: Cysts fenestration for polycystic liver disease. A fluid collection with gas bubbles is found at the fenestration site (arrow). The surgical drain is in place. A fat-density area adjacent to resection margins is observed (arrowheads): epiplooplasty. Page 19 of 31

20 Fig. 13: Natural postoperative evolution of a fluid collection occupying the resection site after bisegmentectomy 4-5 for metastases from gastric GIST. Look at the fibrous retraction at resection margins 10 months after surgery. Fig. 14: Right hepatectomy for a metastasis from colic cancer. An endoluminal hypodensity related to thrombosis of the right portal branch stump is found, in addition to a fluid effusion in the resection site. Page 20 of 31

21 Fig. 15: MDCT scans performed after wedge resection of segment 4. Left: hyperattenuating collection related to a hematoma. Right: fluid collection with gaz bubbles associated with fever related to an infected collection confirmed by punction. Fig. 16: MDCT after right hepatectomy for HCC developed on cirrhotic liver revealing a thrombosis of portal branches of segments 2-3 (arrows). Page 21 of 31

22 Fig. 17: MDCT after left hepatectomy for a large focal nodular hyperplasia revealing a portal trunk thrombosis. Before IV: hyperattenuating material within the portal vein. Portal phase: lack of enhancement of portal vein (arrow), and perfusion abnormalities of hepatic parenchyma. Fig. 18: MDCT after bisegmentectomy 2-3 for metastases from colorectal cancer revealing an incomplete thrombosis of the middle hepatic vein (arrows) close to resection margins. Page 22 of 31

23 Fig. 19: MDCT after segmentectomy 7 for metastases from colorectal cancer revealing a thrombosis of right hepatic vein (arrowheads) extending to inferior vena cava (arrow). Fig. 20: MDCT after right hepatectomy for metastases from colic cancer. Right pleural effusion (*) associated with pleural enhancement (arrows) and right diaphragmatic injury (arrow heads): biloma with fistulization to pleura after peroperative diaphragmatic injury. Page 23 of 31

24 Fig. 21: MDCT after right hepatectomy revealing early small-bowel obstruction after incarcerated hernia through diaphragmatic wound. Saint-Antoine University Hospital, Paris/FR Page 24 of 31

25 Fig. 22: MDCT with IV injection and direct biliary duct opacification through biliary drain (arrow) after cystectomy at junction of segments 4-5 for a liver hydatid cyst. A fluid collection with leakage of contrast material is found at the resection site (*), revealing a postoperative biliocystic fistulae. Page 25 of 31

26 Fig. 23: Top: MDCT performed 6 months after segmentectomy 7 for HCC developed on cirrhotic liver, revealing a large, poorly marginated hepatic hypodensity (arrow) near the resection margins. Middle and bottom: an additional hepatic MR imaging was decided for lesion characterization, revealing a hyperintense lesion on T2WI and DWI with mild arterial contrast enhancement and wash out at late phase: a local intrahepatic recurrence at the resection margins was diagnosed (poorly vascularized HCC). Page 26 of 31

27 Fig. 24: Left hepatectomy for hilar cholangiocarcinoma. Left: MDCT reveals intrahepatic bile duct dilatations. Moreover, subcapsular hypodensities related to distal biliary abscesses can be seen. Middle: MDCT also reveals a fluid collection with active hemorrhage at resection margin. Right: arteriogram highlights blood leakage from injury to the left hepatic artery stump. Fig. 25: MRCP after right hepatectomy: Multiple intrahepatic bile duct stenoses with irregular ductal dilatations. Page 27 of 31

28 Saint-Antoine University Hospital, Paris/FR Page 28 of 31

29 Conclusion In the absence of complications, postoperative liver imaging is not routinely systematically performed. Identifying remaining hepatic portal branches and veins is essential for an accurate analysis of the remaining liver. Fluid collections in the majority of cases belong to normal findings. Early complications are predominantly abnormal fluid collections. Late complications mostly consist of initial disease recurrence. MRCP is the imaging modality of choice for the work-up of patients with suspected postoperative bile duct injury. Page 29 of 31

30 Personal information S. Mulé, Radiology department, Robert Debré University Hospital, Reims, France. A. Colosio, Radiology department, Robert Debré University Hospital, Reims, France. J. Cazejust, Radiology department, Saint-Antoine University Hospital, APHP, Paris, France. P. Soyer, Department of Abdominal Imaging, Lariboisière Hospital, APHP, Paris, France. R. Kianmanesh, Department of Digestive and Endocrine Surgery, Robert Debré University Hospital, Reims, France. C. Hoeffel, Radiology department, Robert Debré University Hospital, Reims, France. Page 30 of 31

31 References Terminology Committee of the IHPBA. Terminology of liver anatomy and resections. HPB. 2000;2: Couinaud C. Le foie. Études anatomiques et chirurgicales. Paris: Masson ; 1957 Huynh-Charlier I, Taboury J, Charlier P et al. Imaging of the postsurgical liver. J Radiol 2009; 90(7-8 Pt 2): Sauvanet A, Zins M. Foie. In : Imagerie de l'appareil digestif opéré. Paris : Flammarion; p Wigham A, Grant L A. Radiologic Assessment of Hepatobiliary Surgical Complications. Semin Ultrasound CT MRI 2013; 34:18-31 Letourneau JG, Steely JW, Crass JR et al. Upper abdomen: CT findings following partial hepatectomy. Radiology 1988; 166(1 Pt 1): Serrablo A, Tejedor L. Outcome of surgical resection in Klatskin tumors. World J Gastrointest Oncol 2013; 15;5(7): de Jong MC, Pulitano C, Ribero D et al. Rates and patterns of recurrence following curative intent surgery for colorectal liver metastasis: an international multi-institutional analysis of 1669 patients. Ann Surg 2009; 250: Wang JK, Truty MJ, Donohue JH. Remnant torsion causing Budd-Chiari syndrome after right hepatectomy. J Gastrointest Surg 2010; 14(5):910-2 Page 31 of 31