The Road Less Traveled: The Often Ignored Lesser Branches of the Celiac Axis Aram Lee, MD Justin McWilliams, MD UCLA Radiology
The Road Less Traveled: The Often Ignored LesserBranches of the Celiac AxisLearning Objectives: To highlight the clinical relevance of lesscommonly encountered vascular branches of the celiacaxis, specifically in liver-directed interventional treatment.Organization:Part 1: Review of classic hepatic arterial anatomy and common hepatic arterial variantsPart 2: Extrahepatic collateral vessels originating from the celiac axis which can be parasitized by liver tumorsPart 3: Extrahepatic branches arising from the hepatic arterial circulation to recognize in liver embolotherapy
Part 1:CLASSIC HEPATIC ARTERIAL ANATOMYAND COMMON ARTERIAL VARIANTS
Conventional hepatic arterial anatomy RHA LHA PHA CHA GDA 61% Conventional hepatic artery anatomy; the CHA gives off the GDA and continues as the PHA, which splits into RHA and LHA. In the surgical literature, 55-70% of the population has this configuration; in the largest DSA study, 61%.Michels et al. Blood supply and antaomy of the upper abdominal organs with a descriptive atlas. Philadelphia, PA: Lippincott, 1955.Hiatt et al. Surgical anatomy of the hepatic arteries in 1000 cases. Ann Surg 1994; 220: 50-52.Covey et al. Variant hepatic arterial anatomy revisited: DSA performed in 600 patients. Radiology 2002; 224: 542-547.
Left hepatic artery Origin -Proper hepatic artery -Left gastric artery (5%) -Celiac trunk (rare, double hepatic artery) Supplies -Segments 2 and 3, and sometimes 4 Recognized by -Arch over L portal vein -Distribution to L lobe of liverCovey et al. Variant Hepatic Arterial Anatomy Revisited: DSA Performed in 600 Patients. Radiology. August 2002. 224: 542-547.
Right hepatic artery Origin Proper hepatic artery SMA (12%) Celiac trunk (double hepatic artery) Destination Segments 5-8 Recognized by Distribution to right lobe of liverCovey et al. Variant Hepatic Arterial Anatomy Revisited: DSA Performed in 600 Patients. Radiology. August 2002. 224: 542-547.
Replaced or accessory right hepatic artery Replaced right hepatic artery (12%) -No right hepatic artery from PHA -Instead originates from the SMA, or rarely the right phrenic artery or other Accessory right hepatic artery (5.5%) -Right hepatic artery from PHA -Second right hepatic artery from elsewhere -Usually SMA Replaced RHA from SMA -Also GDA, LGA, celiac axis, right phrenic arteryHiatt et al. Surgical Anatomy of the Hepatic Arteries in 1000 Cases. Annals of Surgery. July 1994. 220: 50-52.Covey et al. Variant Hepatic Arterial Anatomy Revisited: DSA Performed in 600 Patients. Radiology. August 2002. 224: 542-547
Replaced or accessory left hepatic artery Replaced left hepatic artery -Entire left hepatic artery originates elsewhere other than the PHA (4.5 %) -Commonly originates from the left gastric artery Accessory left hepatic - Part (but not all) of the left hepatic artery has an anomalous origin (15%) - Almost always originates from left Replaced left hepatic artery arising from left gastric gastric artery, very rarely from RHA artery. Left gastric branches (arrowheads) can mimic segment 2 or 3 branches; true left hepatic branches take off beyond the umbilical point (arrow).Hiatt et al. Surgical Anatomy of the Hepatic Arteries in 1000 Cases. Annals of Surgery. July 1994. 220: 50-52.Covey et al. Variant Hepatic Arterial Anatomy Revisited: DSA Performed in 600 Patients. Radiology. August 2002. 224: 542-547
Middle hepatic arteryMiddle hepatic artery from RHA Middle hepatic artery from Proper Hepatic Artery (trifurcation)A “middle hepatic artery” supplying segment 4 can arise from PHA as atrifurcation, or from the right hepatic artery
Double replaced hepatic artery Celiac injection demonstrates absence of RHA and LHA. Expected course of CHA (arrow) terminates in GDA and RGA. 0.5% Replaced LHA from LGA Replaced RHA from SMACovey et al. Variant hepatic arterial anatomy revisited: DSA performed in 600 patients. Radiology 2002; 224: 542-547.
Replaced common hepatic artery 2% Injection of celiac axis demonstrates splenic and left Common hepatic artery arises from the superior mesenteric gastric arteries, but no common hepatic artery. artery.Hiatt et al. Surgical Anatomy of the Hepatic Arteries in 1000 Cases. Annals of Surgery. July 1994. 220: 50-52.
Part 2:EXTRAHEPATIC COLLATERAL VESSELSORIGINATING FROM THE CELIAC AXISWHICH CAN BE PARASITIZED BY LIVERTUMORS
Extrahepatic collaterals in liver tumor therapy Only tumors with surface location 17% overall likelihood of extrahepatic supply at initial presentation 3% for tumors <4 cm 63% for tumors >6 cm Likelihood of extrahepatic supply increases with repeated embolizationsChung et al. Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma: Prevalence and Causative Factors of Extrahepatic CollateralArteries in 479 Patients. Korean J Radiol. 2006 Oct; 7(4): 257-266.
Extrahepatic collaterals to consider Where to look based on tumor location Bare area of liver (seg 7/8): R phrenic and R adrenal Superior-anterior liver (cardiophrenic area): R internal mammary Exophytic toward kidney: R renal and R adrenal Any peritoneal surface: Omental branches from R gastroepiploic Contacts chest wall: Lower intercostal Left lateral segment: L gastric Contacts colon: Colic branches of SMA Gallbladder fossa: Cystic Bare area = Posterior surface of segment 7 and posterior half of the diaphragmatic surface of segment 8 .Chung et al. Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma: Prevalence and Causative Factors of Extrahepatic CollateralArteries in 479 Patients. Korean J Radiol. 2006 Oct; 7(4): 257-266.
Right inferior phrenic artery Origin Aorta 50% (12% as common trunk with LIPA) Celiac trunk 40% (16% as common trunk with LIPA) Right renal artery 5% Left gastric artery 4% Rarely other Supplies Right hemidiaphragm Suspect HCC supply for tumors in segment 7 abutting the diaphragm 50% of collateral supply Effects of embolization Usually well-tolerated Shoulder pain Pleural effusion Basal atelectasis Transient hemoptysis Diaphragmatic weakness (usually asymptomatic)Basile A et al. MDCT anatomic assessment of right inferior phrenic artery origin related to potential supply to hepatocellular carcinoma and itsembolization. CVIR 2008.
HCC involvement of the right inferior phrenic artery Replaced RHA angiogram demonstrates tumor supply. DEB- Infiltrative HCC of the right lobe TACE was performed. 1 month post-TACE, tumor necrosis is seen, but persistent Right phrenic angiography demonstrates copious enhancement is seen at the posterior diaphragmatic margin. tumor supply. DEB-TACE was performed from this location.
Omental arteries Origin Right or left gastroepiploic artery Supplies Greater omentum (mobile!) Can supply tumors on almost any surface of the liver Effects of embolization Usually well-tolerated 15% of collateral supply After multiple TACEs, common hepatic injection demonstrates multiple omental branches (arrows) from the R gastroepiploic artery supplying right lobe HCC (arrowheads).Kim HC et al. Recognizing extrahepatic collateral vessels that supply hepatocellular carcinoma to avoid complications of transcatheter arterialchemoembolization. Radiographics 2005.Image courtesy of Antoinette Gomes, MD.
Cystic Artery Origin Usually first branch of right hepatic artery Supplies Gallbladder HCC in gallbladder fossa Recognized by Proximal bifurcation Curved shape outlining viscus Effects of embolization Cystic artery injection demonstrates parasitic Cholecystitis/gallbladder infarction Often asymptomatic 9% of collateral supply supply to HCC (arrow).Kim HC et al. Recognizing extrahepatic collateral vessels that supply hepatocellular carcinoma to avoid complications of transcatheter arterialchemoembolization. Radiographics 2005.Image courtesy of David Liu, MD.
Right adrenal artery Origin Superior adrenal artery from right inferior phrenic artery Middle adrenal artery from lateral aorta between the celiac and renal arteries 6% of collateral supply Inferior adrenal artery from superior aspect of right renal artery Supplies Right adrenal gland May supply tumor which extends inferomedially Effects of embolization Usually well-toleratedKim HC et al. Recognizing extrahepatic collateral vessels that supply hepatocellular carcinoma to avoid complications of transcatheter arterialchemoembolization. Radiographics 2005.
Uncommon sources of collateral supply Right adrenal artery (6%) Right intercostal arteries (5%) Right or left gastric artery (3%) Right internal mammary artery (3%) Superior mesenteric artery (2%) Right renal capsular artery (2%) Left inferior phrenic artery (2%) Right adrenal arteryKim HC et al. Recognizing extrahepatic collateral vessels that supply hepatocellular carcinoma to avoid complications of transcatheter arterial chemoembolization.Radiographics 2005.
Part 3:EXTRAHEPATIC BRANCHES ARISINGFROM THE HEPATIC ARTERIALCIRCULATION TO RECOGNIZE IN LIVEREMBOLOTHERAPY
Vascular optimizationProtective coil embolization of extrahepatic branches arising from the hepatic circulation prior to embolotherapy 1. Gastroduodenal artery 2. Right gastric artery 3. Accessory left gastric artery Other vessels to consider: 4. Retroduodenal artery -Dorsal pancreatic artery 5. Supraduodenal artery -Left phrenic artery -Esophageal branches 6. Falciform artery 7. Cystic arteryCoil embolization of these vessels (when necessary) prevents passage of particles (DEB or Y90) into sensitive structures
Accessory left gastric Right gastric Falciform Left phrenicCysticSupraduodenalRetroduodenal Right gastric Supraduodenal Retroduodenal Dorsal pancreatic
Gastroduodenal ArteryOrigin Common hepatic arterySupplies Pylorus of stomach Proximal duodenum Pancreatic head (via pancreaticoduodenals) Greater curvature of stomach (via R gastroepiploic)Anatomic Clues Near constant origin from CHA Characteristic branching pattern The gastroduodenal artery arises from the CHA. It typically gives off the posterior superior pancreaticoduodenal artery (curved arrow), then bifurcates into the anterior superior pancreaticoduodenal artery (arrow) and the right gastroepiploic artery (arrowhead).
Gastroduodenal ArteryConsiderations for optimization: -Should be coil embolized in almost all cases -High flow, need lots of coils to occlude (usually 5-7 mm coils) -Coil all the way back to origin to avoid hypertrophy of small proximal vessels -Look for accessory hepatic arteries and parasitized tumor supply -GDA flow reversed? If due to low hepatic artery resistance, best to coil If due to celiac stenosis, probably OK not to coil GDA with reversed flow. Depending on the etiology, this may or may not require coil embolization.
Right gastric artery Origin -Proper hepatic artery (55%) -Left hepatic artery (20%) -Common hepatic artery (5%) -Gastroduodenal artery (5%) -Right or middle hepatic artery (rare) Right gastric artery (arrow) arising from the origin of the gastro- duodenal artery. Note anastomoses with the left gastric artery. Destination -Gastric antrum and pylorus -Proximal duodenal bulb Anatomic Clues -Leftward course along lesser curvature of stomach -Anastomoses with left gastric artery Right gastric artery (arrow) arising from the left hepatic artery.VanDamme JP, Bonte J. Vascular anatomy in abdominal surgery. New York: Thieme, 1990.Yamagami et al. Embolization of the right gastric artery before he- patic arterial infusion chemotherapy to prevent gastric mucosal lesions: approachthrough the hepatic artery versus the left gastric artery. AJR Am J Roentgenol 2002; 179:1605�1610.
Right gastric artery Considerations for optimization Should be coil embolized in almost all patients -Unnecessary if RGA origin is very proximal (CHA) May have acute angle, difficult to catheterize Options for difficult cannulation -Shaped microcatheter -Ultra-floppy wire (Synchro) -Retrograde access via left gastric artery -“Jail” right gastric by coiling left hepatic artery -If all else fails, can deliver particles distal to origin Right gastric artery accessed retrograde from the left gastric artery, followed by coil embolization. Image courtesy of David Liu, MD.Yamagami et al. Embolization of the right gastric artery before he- patic arterial infusion chemotherapy to prevent gastric mucosal lesions: approach through thehepatic artery versus the left gastric artery. AJR Am J Roentgenol 2002; 179:1605-1610.
Dorsal Pancreatic Artery Origin Considerations for Vascular Optimization - Splenic artery (60%) - No, in most cases - Common hepatic artery (15%) - Sufficiently proximal (splenic/celiac) origin - SMA (10%) to avoid collateral damage - Celiac (10%) - Rarely others - Yes, in a few cases - Common hepatic or more distal origin - Copious pancreatic collaterals allow safe coiling Destination - Pancreatic head - Pancreatic body (via transverse pancreatic artery) Anatomic Clues - Usual origin within 2 cm of the celiac terminus - Courses down and right if from splenic; down and left if from CHA; up if from SMA - Characteristic branching pattern -Leftward branch into transverse pancreatic artery -Rightward branches collateralize with superior pancreaticoduodenal arcade Dorsal pancreatic artery arising from the celiac artery terminus.Bertelli et al. The arterial blood supply of the pancreas: a review. V. The dorsal pancreatic artery. An anatomic review and a radiologic study. SurgicalRadiologic Anatomy. 1998;20(6):445-52.
Accessory left gastric artery Prevalence 3-21% (high in Asian populations) Origin Left hepatic artery in proximal portion – 60% Left hepatic artery in distal portion – 40% Destination Gastric cardia and fundus Anatomic Clues Runs in the fissure of the ligamentum venosum (same place as a replaced left hepatic artery) on CT Considerations for optimization Should be coil embolized if present Often difficult to identify on angio Proximal-type accessory left gastric artery (arrow) arises from Tips for identification the LHA prior to the umbilical point and courses to the gastric -Gastric mucosal enhancement fundus (arrowheads). -Delayed-phase coronary vein filling -Use cone beam CTIshigami K, Yoshimitsu K, Irie H, et al. Accessory left gastric artery from left hepatic artery shown on MDCT and conventional angiography: correlation with CThepatic arteriography. Am J Roentgenol 2006;187:1002-1009.
Supraduodenal Artery (of Wilkie) Origin Gastroduodenal artery – 26% Common or proper hepatic artery – 20% Left hepatic artery – 20% Right hepatic artery – 13% Cystic artery – 10% Right gastric artery – 8% Destination Proximal duodenum Anatomic Clues Extremely variable origin Small branch Distribution to duodenal bulb area Considerations for optimization Often not visualized (though almost always present) Be suspicious if branch from hepatic artery passes inferomedially toward duodenum Coil embolize if originating from hepatic circulation (about 50%) Supraduodenal artery (arrows) arises from the proper hepatic artery and passes toward the proximal duodenum.Bianchi et al. The supraduodenal artery, Surg Radiol Anat 11 ( 1989), pp. 37-40.Image courtesy of David Liu, MD
Retroduodenal Artery Also known as the posterior superior pancreaticoduodenal artery Origin Gastroduodenal artery – 78% Hepatic artery (proper or right) – 15% Superior mesenteric artery – 5% Destination Head of pancreas Uncinate process Duodenal bulb Anatomic Clues Runs along common hepatic duct Parallels 2nd segment of duodenum Considerations for optimization No need to coil embolize in most cases The retroduodenal artery (arrows) typically arises as the first branch of the gastroduodenal artery. Coil embolize if originating from the hepatic arteryVanDamme JP, Van der Schueren G, Bonte J. Vascularisation du pancreas: proposition de nomenclature PNA et angioarchitecture des ilots. C R Assoc Anat 1968;139:1184 –1192.
Falciform Artery Origin Middle hepatic artery – 56% Left hepatic artery – 44% Destination Anterior abdominal wall, umbilical region Anatomic Clues Courses anteriorly and diagonally toward the Falciform artery (arrow) arising from the left hepatic artery, early phase. midline (paralleling the falciform ligament) Considerations for optimization Coil embolize if present (2%) Lack of protection can result in abdominal wall injury, pain, and/or rash Late phase confirms typical course of falciform arteryBaba et al. HEPATIC FALCIFORM ARTERY: Angiographic findings in 25 patients. Acta Radiologica. Volume 41:4 July 2000 , pages 329 - 333.Williams et al. Hepatic falciform artery: anatomy, angiographic appearance, and clinical significance. Radiology 1985. 156: 339-340.
Cystic Artery Origin Right hepatic artery – 90% Left hepatic artery – 7% Common hepatic artery – 3% Gastroduodenal artery – 1% Destination Gallbladder Anatomic Clues Typically the first branch of right hepatic artery Bifurcation into superficial and deep branches Network of vessels outlining viscus Considerations for optimization Coil embolization can rarely lead to ischemic cholecystitis Lack of coil embolization can rarely lead to Cystic artery (arrow) arising from the anterior division branch of the chemical or radiation cholecystitis right hepatic arteryDaseler EH, Anson BA, Hambley WC, Reimann AF. The cystic artery and constituents of the hepatic pedicle. A study of 500 specimens. Surg GynecolObstet 1947: 85: 47–63
Summary-Extrahepatic collaterals originating from the celiac axisshould be considered in hepatic tumor treatment includingthe inferior phrenic, omental, and adrenal arteries.- “Lesser” branches of the celiac axis specifically arisingfrom the hepatic circulation should be recognized invascular optimization of liver-directed therapy. Thesebranches include the gastroduodenal, right gastric,accessory gastric, dorsal pancreatic, supraduodenal,retroduodenal, falciform, and cystic arteries.