Physiological Basis of Liver Function Tests and Their Significance in Surgical Conditions

Introduction

1. Hepatocellular injury (transaminases)
2. Abnormal synthetic function (albumin, PT/INR)
3. Cholestasis (bilirubin, ALP, GGT)

1. Serum Bilirubin

Physiological Basis

• Prehepatic phase: RBC destruction releases hemoglobin → heme is converted by heme oxygenase to biliverdin → biliverdin reductase converts it to unconjugated (indirect) bilirubin. Unconjugated bilirubin is lipid-soluble and insoluble in water; it is transported to the liver bound to albumin.
• Intrahepatic phase: In hepatocytes, unconjugated bilirubin is conjugated with glucuronic acid by UDP-glucuronosyltransferase, becoming water-soluble conjugated (direct) bilirubin. The rate-limiting step is excretion of conjugated bilirubin from hepatocytes into bile canaliculi.
• Posthepatic phase: Conjugated bilirubin is secreted into bile and passes to the duodenum.

Surgical Significance

• Obstructive jaundice: Elevated direct (conjugated) bilirubin indicates extrahepatic obstruction - choledocholithiasis, cholangiocarcinoma, carcinoma head of pancreas, ampullary carcinoma, post-surgical biliary stricture. Because conjugated bilirubin is water-soluble, it appears in urine (dark urine = bilirubinuria).
• Serial monitoring: Total bilirubin should be repeated every 3-4 days in surgical jaundice. A falling level is a favorable sign; a sudden rise indicates deterioration (Pye's Surgical Handicraft).
• Preoperative risk: Obstructive jaundice increases operative risk significantly - patients are at risk for hepatorenal syndrome, coagulopathy, infection, and poor wound healing. Bilirubin >10 mg/dL substantially raises perioperative mortality.
• Partition into fractions: Although previously used to differentiate hepatic from posthepatic jaundice, the direct van den Bergh reaction measures both mono- and diglucuronides, making fractionation unreliable for this distinction alone. However, elevated indirect fraction strongly suggests prehepatic (hemolytic) cause.

2. Aminotransferases (Transaminases) - AST and ALT

Physiological Basis

• AST (aspartate aminotransferase / SGOT): Catalyzes transfer of amino group from aspartate to alpha-ketoglutarate → oxaloacetate. Found in liver, cardiac muscle, skeletal muscle, kidney, brain, pancreas, lungs, and RBCs. Less specific for liver.
• ALT (alanine aminotransferase / SGPT): Catalyzes transfer from alanine → pyruvate. Found predominantly in hepatocytes, making it the more liver-specific enzyme. Elevation in ALT is the most useful test to distinguish hepatocellular damage from posthepatic obstruction as a cause of jaundice.

Surgical Significance

• Preoperative assessment: Significantly elevated transaminases (>3x normal) indicate active hepatocellular damage; elective surgery should be deferred.
• Hepatic ischemia detection: Transaminases spike dramatically in hepatic artery thrombosis post-liver transplant, ischemic hepatitis from hypotension/shock (ischemic hepatopathy - "shock liver"), or Pringle maneuver-related ischemic damage during hepatic surgery.
• Post-hepatectomy monitoring: Rising transaminases after liver resection suggest ongoing hepatocellular injury or post-hepatectomy liver failure.
• Blunt abdominal trauma: Elevation of AST/ALT serves as a sensitive marker for hepatic laceration - AST >450 U/L or ALT >250 U/L has high sensitivity for liver injury in trauma.
• Note: Transaminase levels correlate poorly with severity of hepatocellular necrosis - they may not be elevated in cirrhosis or hepatic fibrosis.

3. Alkaline Phosphatase (ALP)

Physiological Basis

• Bone disease: Rickets, osteomalacia, Paget's disease, hyperparathyroidism, bony metastases
• Third trimester of pregnancy (placental isoenzyme)

Surgical Significance

• Cholestatic pattern: ALP elevation (often >3x) with high bilirubin and GGT = cholestasis. This is the classic pattern in carcinoma head of pancreas, cholangiocarcinoma, primary sclerosing cholangitis (PSC).
• Metastatic liver disease: ALP may be raised from either hepatic involvement OR bone metastases. Distinguished by GGT measurement (GGT elevated with hepatic cause; normal with bony cause) or isoenzyme fractionation.
• Post-transplant biliary complications: Rising ALP post-liver transplant suggests biliary stricture or anastomotic leak.
• PSC: Markedly elevated ALP is a hallmark; PSC has strong associations with inflammatory bowel disease and is a premalignant condition for cholangiocarcinoma - surgical resection or transplant is definitive management.

4. Gamma-Glutamyl Transferase (GGT)

Physiological Basis

• Alcohol abuse (microsomal enzyme induction)
• Certain medications (phenytoin, phenobarbitone)
• Pancreatic disease, myocardial infarction, renal failure, obstructive pulmonary disease

Surgical Significance

• Confirms hepatic origin of elevated ALP: GGT + ALP both elevated = hepatobiliary cause. ALP elevated + GGT normal = bony cause.
• Alcohol screening: Persistently elevated GGT in the preoperative period suggests chronic alcohol intake - important for anaesthetic planning (altered drug metabolism, risk of alcohol withdrawal post-surgery, thrombocytopenia, coagulopathy).
• Sensitive early marker: GGT rises before other LFTs in early biliary obstruction and in drug-induced liver injury.

5. Serum Albumin

Physiological Basis

Surgical Significance

• Preoperative nutritional marker: Hypoalbuminaemia (<3.5 g/dL) is an independent predictor of surgical complications - poor wound healing, anastomotic dehiscence, increased infection risk, impaired drug binding.
• Chronic liver disease assessment: Albumin is a key component of the Child-Pugh Score for assessing hepatic reserve.
• NOT a marker of acute hepatic failure due to its long half-life - PT/INR is superior in acute settings.
• Cirrhosis: Low albumin + ascites + coagulopathy = decompensated cirrhosis, usually a contraindication to major elective surgery.

6. Prothrombin Time (PT) and INR

Physiological Basis

1. Hepatocellular failure (reduced synthesis)
2. Vitamin K deficiency (malabsorption, biliary obstruction - fat-soluble vitamin)
3. Anticoagulant therapy (warfarin)

Surgical Significance

• Best acute marker of hepatic synthetic function - short half-life of factor VII (~4-6 hours) makes PT/INR sensitive for acute liver failure.
• Preoperative coagulation assessment: PT >3 seconds above control (INR >1.5) is a contraindication to elective hepatic surgery without correction.
• Biliary obstruction: Prolonged PT in obstructive jaundice = fat malabsorption → Vit K deficiency → correctable with parenteral vitamin K (10 mg IV for 3 days). Failure to correct suggests hepatocellular component.
• Child-Pugh classification: INR is a component - INR >2.3 scores 3 points (worst category).
• Liver failure monitoring: Serial PT/INR is the most sensitive laboratory indicator of progression or recovery in acute liver failure.

7. Composite Scoring Systems - Surgical Decision Making

Child-Pugh Score

• Class A (5-6 points): Well-compensated; suitable for major hepatic resection
• Class B (7-9 points): Significant functional compromise; only highly selected patients suitable for resection
• Class C (10-15 points): Decompensated cirrhosis; mortality from surgery is prohibitive - surgery should be avoided; may be considered for transplant listing

MELD Score

• Estimates 3-month mortality in patients with chronic liver disease
• Used by UNOS for organ allocation in liver transplantation
• Less useful for predicting post-hepatectomy failure compared to Child-Pugh
• MELD <9 with Child-Pugh A = favorable for liver resection in HCC

ICG Retention Test

• Normal ICG-R15: 1-10%
• ICG-R15 <10% = adequate reserve for major liver resection in cirrhotic patients
• Widely used in Asia (Japan) for hepatic reserve assessment before hepatectomy
• Must be combined with volumetric FLR (future liver remnant) assessment

8. Additional Surgically Relevant Tests

Pseudocholinesterase

• Pseudocholinesterase (plasma cholinesterase) is responsible for metabolism of succinylcholine and mivacurium
• In severe liver disease, prolonged neuromuscular blockade can occur with these agents

Serum Ammonia

• Converted in liver via the urea cycle
• Elevated in hepatic failure / porto-systemic shunting
• Clinical significance: Hepatic encephalopathy - ammonia is neurotoxic
• Surgical importance: Portosystemic shunting procedures (e.g. TIPS, surgical shunts) may worsen encephalopathy by bypassing hepatic detoxification

5'-Nucleotidase and Leucine Aminopeptidase

• Elevated in hepatocellular damage
• Used to confirm hepatic origin of elevated ALP when GGT is unavailable

9. Patterns of LFT Abnormality in Common Surgical Conditions

Conclusion

1. Classify the type of liver dysfunction (hepatocellular vs. cholestatic vs. synthetic failure)
2. Stratify surgical risk using Child-Pugh, MELD, and ICG retention
3. Identify reversible causes (Vit K deficiency, biliary obstruction) before surgery
4. Monitor postoperative hepatic recovery
5. Time elective surgery appropriately - avoiding operating during active hepatocellular inflammation or decompensated cirrhosis

• Schwartz's Principles of Surgery, 11th Edition (Hepatocellular Injury, Cholestasis, Jaundice chapters)
• Mulholland and Greenfield's Surgery, 7th Edition (Preoperative Evaluation of Hepatic Reserve, Child-Pugh, MELD, ICG)
• Pye's Surgical Handicraft, 22nd Edition (Liver Function Tests in Surgical Jaundice)
• Bailey and Love's Short Practice of Surgery, 28th Edition

QUESTION 1: Hepatitis B (10 Marks)

Introduction

Virology and Replication

• S gene - encodes surface antigen (HBsAg) in three forms: large, middle, and small
• C gene - encodes core antigen (HBcAg) and e antigen (HBeAg)
• P gene - encodes DNA polymerase (with reverse transcriptase activity)
• X gene - product not fully characterized; involved in transactivation

Serological Markers and Their Significance

Recommended Test Panels:

• Acute HBV: HBsAg + IgM anti-HBc
• Chronic HBV: HBsAg + IgG anti-HBc + IgG anti-HBs
• Monitoring chronic infection: HBsAg, HBeAg, anti-HBs, anti-HBe, quantitative HBV DNA PCR

Natural History and Clinical Features

Pathology

• Acute HBV: Lobular hepatitis, hepatocyte ballooning, acidophil bodies (apoptotic hepatocytes = Councilman bodies), lymphocytic infiltrate
• Chronic HBV: "Ground glass" hepatocytes (HBsAg accumulation in ER), periportal fibrosis, bridging fibrosis → cirrhosis
• Mechanism of injury: primarily immune-mediated (CD8+ T-cell killing of infected hepatocytes), not direct viral cytopathic effect

Treatment

Surgical Relevance

1. Preoperative screening: All surgical patients should be screened for HBsAg - active HBV may decompensate with surgical stress
2. Universal precautions: High infectivity of HBV (viable on dry surfaces for >7 days, HBsAg-positive blood is highly infectious); needlestick transmission ~30%
3. Liver resection in HBV: HBV-related HCC is a common indication for hepatectomy; viral suppression with antiviral therapy pre- and post-operatively is mandatory to prevent post-hepatectomy liver failure and HCC recurrence
4. Liver transplantation: HBV-related cirrhosis/HCC is a major indication for LT; post-transplant HBIg + antivirals prevent graft reinfection
5. Post-transplant reactivation: Immunosuppression after any organ transplant or chemotherapy can reactivate occult HBV (anti-HBc positive, HBsAg negative); screen all candidates and use prophylactic antivirals
6. Coagulopathy and hepatic reserve: Chronic HBV with cirrhosis - assess Child-Pugh/MELD before any elective surgery

QUESTION 2: Hepatorenal Syndrome (20 Marks)

Definition

Epidemiology

• Acute renal dysfunction occurs in 15-25% of hospitalized cirrhotic patients
• HRS accounts for 10-30% of these cases
• Annual frequency in cirrhotic patients with ascites: ~8% (up to 40% in some reports)
• HRS develops in ~30% of cirrhotic patients admitted with SBP, 25% with severe alcoholic hepatitis, and 10% requiring serial large-volume paracentesis

Pathophysiology

1. Splanchnic Arterial Vasodilation

• Splanchnic and systemic vasodilation
• Decreased effective arterial blood volume
• Decreased mean arterial pressure (MAP)

2. Compensatory Renal Vasoconstriction

• Stimulation of the sympathetic nervous system (SNS)
• Activation of the renin-angiotensin-aldosterone system (RAAS)
• Non-osmotic release of arginine vasopressin (ADH)
• Local intrarenal effects: altered endothelins, prostaglandins, kallikreins

3. Cardiac Dysfunction (Cirrhotic Cardiomyopathy)

Summary Cascade:

Cirrhosis → Portal hypertension → Splanchnic vasodilation → ↓ Effective circulating volume → RAAS + SNS + ADH activation → Renal vasoconstriction → ↓ GFR → Renal failure

Classification (ICA 2015 Updated Criteria)

Diagnostic Criteria (International Club of Ascites, 2015)

1. Cirrhosis with ascites
2. AKI - serum creatinine rise ≥0.3 mg/dL in 48 hrs OR ≥50% rise from baseline within 7 days
3. No response after at least 2 days of diuretic withdrawal AND albumin volume expansion (1 g/kg/day, max 100 g/day)
4. Absence of shock
5. No recent nephrotoxic agents (NSAIDs, ACEIs, ARBs, aminoglycosides)
6. No intrinsic renal disease - proteinuria <500 mg/day, no microhematuria, normal renal ultrasound

• Oliguria (urine output <500 mL/day)
• Urine sodium <10 mmol/L (avid sodium retention)
• Urine osmolality > plasma osmolality
• Urine red cells <50/HPF
• Normal renal ultrasound

Precipitating Factors

Differential Diagnosis

Prevention

• Avoid excessive diuresis
• Give albumin (1.5 g/kg on day 1, then 1 g/kg on day 3) with IV antibiotics in SBP - reduces HRS development by 40% and significantly reduces mortality (Sort et al. NEJM 1999)
• Avoid nephrotoxic drugs in patients with ascites
• Treat infections promptly (SBP prophylaxis with norfloxacin/ciprofloxacin in high-risk patients)
• Administer albumin (6-8 g per litre drained) after large-volume paracentesis (>5 L)
• Pentoxifylline (400 mg TDS) in severe alcoholic hepatitis - reduces incidence of HRS

Treatment

General Measures

• Discontinue all nephrotoxic agents (ACEIs, ARBs, NSAIDs, diuretics)
• Treat precipitating infections with antibiotics
• IV albumin: bolus 1 g/kg/day on presentation (max 100 g), then 20-60 g/day to maintain CVP 10-15 cm H₂O

Vasopressor Therapy (in combination with albumin)

• Vasopressin V1 receptor agonist → splanchnic vasoconstriction
• Start: 1 mg IV every 4 hours; increase to 2 mg every 4 hrs if creatinine does not improve by 25% at day 3
• Most evidence-based option; reverses HRS in 40-50% of cases
• Duration: maximum 2 weeks, until HRS reverses or liver transplant performed

• Midodrine (alpha-1 agonist, oral): 2.5-5 mg TDS, up to max 15 mg TDS
• Octreotide (inhibits glucagon, reduces splanchnic vasodilation): 100-200 µg SC TDS OR 25 µg/hr IV infusion
• Titrate midodrine to achieve MAP increase of ≥15 mmHg

• 0.1-0.7 µg/kg/min IV infusion
• Increase by 0.05 µg/kg/min every 4 hrs to achieve MAP increase of ≥10 mmHg

Renal Replacement Therapy (RRT)

• Used as bridge to liver transplantation
• Does not improve outcome unless liver recovers or transplant is performed
• Not recommended for non-transplant candidates given dismal prognosis

TIPS (Transjugular Intrahepatic Portosystemic Shunt)

• Reduces portal hypertension → reduces splanchnic vasodilation
• Useful in type 2 HRS / refractory ascites
• Contraindicated in Child-Pugh C with severe hepatic dysfunction, active sepsis, encephalopathy

Liver Transplantation (Definitive Treatment)

• The only curative option for HRS
• Post-transplant, renal function recovers in most patients (since HRS is functional, not structural)
• Consider simultaneous liver-kidney transplant if HRS has persisted >4-6 weeks (risk of irreversible renal damage)

Prognosis

• Type 1 HRS (AKI-HRS): median survival without treatment <2 weeks; 3-month mortality >80%
• Type 2 HRS (CKD-HRS): median survival 3-6 months
• Successful reversal with vasoconstrictors improves short-term survival and serves as bridge to transplant
• Post-liver transplant: most HRS reverses; 5-year survival similar to non-HRS transplant recipients

QUESTION 3: Biliary Fistula (10 Marks)

Definition

• Internal: between biliary tree and a hollow viscus (e.g., duodenum, colon, stomach)
• External: between biliary tree and the skin surface (biliary cutaneous fistula)

Aetiology and Classification

A. Internal Biliary Fistula (Entero-biliary/Cholecystoenteric)

B. External Biliary Fistula (Post-operative/Post-traumatic)

1. Iatrogenic bile duct injury - commonest cause. Incidence <0.5% after laparoscopic cholecystectomy, slightly less with open cholecystectomy. Incidence has increased since the advent of laparoscopic cholecystectomy
2. CBD exploration (T-tube leak/dislodgement)
3. Liver trauma/resection - one-third of liver trauma complications are biliary
4. Spontaneous: from long-standing untreated biliary disease, perforated hydatid cyst, hepatic abscess
5. Post-liver transplant anastomotic leak

C. Physiological Effects of Biliary Fistula

• Intestinal bile acid concentration falls below critical micellar concentration
• Malabsorption of fat-soluble vitamins (A, D, E, K) occurs
• Fat malabsorption (especially long-chain saturated fatty acids)
• Vitamin K deficiency → coagulopathy (prolonged PT/INR)
• Vitamin D deficiency → osteomalacia (long-standing cases)
• Net result: negative bile acid balance despite maximal synthesis

Clinical Features

External Biliary Fistula (Post-operative):

• Usually presents within 1 week of surgery (Goldman-Cecil)
• Abdominal pain (90%), tenderness (80%), fever (75%), nausea/vomiting (50%), jaundice (40%)
• Bilious output from surgical drains is diagnostic
• Clinically detectable ascites is rare
• Biochemical testing is nonspecific: variable elevation in LFTs and WBC

Internal Biliary Fistula:

• May be asymptomatic (discovered incidentally)
• Cholangitis - recurrent episodes (bacteria colonize biliary tree from bowel)
• Pneumobilia on plain X-ray/CT (air in biliary tree from communication with bowel)
• Gallstone ileus (see above)
• Diarrhea (bile acids in colon)
• Steatorrhea (fat malabsorption)

Post-traumatic Biliary Fistula:

• Biloma (contained bile collection): may present as RUQ pain, fever, rising bilirubin
• Bile peritonitis: systemic inflammatory response, peritonism, sepsis

Investigations

Management

External Biliary Fistula

1. Small leaks (<300 mL/day): Percutaneous drainage + ERCP with sphincterotomy and biliary stent placement → most close spontaneously
   • Sphincterotomy reduces resistance to bile flow → bile preferentially passes into duodenum rather than leaking
2. Larger/persistent leaks: Percutaneous drainage + ERCP with stent + sphincterotomy
3. Bile peritonitis: Percutaneous/laparoscopic washout and drainage; open surgery rarely indicated
4. PTBD (Percutaneous transhepatic biliary drainage): When ERCP fails or for proximal lesions

• Hepaticojejunostomy (Roux-en-Y): Gold standard for bile duct injury repair; creates bilio-enteric anastomosis
• Timing: If bile duct injury recognized intraoperatively → immediate repair. If delayed → wait 6-8 weeks for inflammation to settle

• Correct fat-soluble vitamin deficiencies (Vitamin K IV/IM, Vitamins A, D, E supplementation)
• Medium-chain triglycerides (MCTs) are better absorbed (don't require bile micelles)
• Total parenteral nutrition if severe malabsorption

Internal Biliary Fistula

• Surgical management: cholecystectomy + closure of fistulous opening + primary repair or bowel resection of affected segment
• Gallstone ileus: Enterolithotomy (stone extraction) ± cholecystectomy with fistula repair (one or two-stage depending on patient condition)

Classification by Stump Closure

• Type I (external compression): cholecystectomy
• Type II-III (partial CBD erosion): bile duct repair
• Type IV (complete CBD obliteration): Roux-en-Y hepaticojejunostomy

Prognosis

• Most postoperative bile leaks (small fistulae) resolve with endoscopic management and percutaneous drainage
• Major bile duct injuries without proper repair progress to biliary stricture → secondary biliary cirrhosis → liver failure
• Mortality of untreated bile peritonitis: high
• After successful Roux-en-Y hepaticojejunostomy: excellent long-term outcomes if performed at specialized centres

• Goldman-Cecil Medicine (Biliary Fistula, Cholestatic Liver Disease)
• Sleisenger & Fordtran's GI and Liver Disease (HRS Pathophysiology and Treatment; Biliary Fistula)
• Fischer's Mastery of Surgery, 8th Edition (Biloma, Biliary Fistula, Bile Leak)
• Current Surgical Therapy, 14th Edition (Hepatorenal Syndrome)
• Henry's Clinical Diagnosis by Laboratory Methods (Hepatitis B serology)
• Robbins & Cotran Pathologic Basis of Disease (HBV pathology and natural history)
• Jawetz Medical Microbiology, 28th Edition (HBV virology)

Magnetic Resonance Cholangiopancreatography (MRCP) - 10 Mark University Answer

Introduction

Physical Principles and Technical Basis

• Heavily T2-weighted fast spin-echo sequences (HASTE/RARE): Stationary or slow-moving fluid (bile, pancreatic juice) in the ductal system appears as bright (hyperintense) signal, while background solid tissues (liver parenchyma, fat, moving blood) are suppressed to near-zero signal. This produces an "endoscopy-like" roadmap of the ductal anatomy.
• No exogenous contrast required for standard MRCP (unlike CT-IVC). Bile itself is the intrinsic contrast agent.
• Two main acquisition techniques:
  • Single-slab (thick-collimation 30-70 mm): Rapid acquisition in 2-3 seconds; ERCP-like overview images in oblique coronal plane; can be acquired in multiple rotational angles
  • Multi-slice thin-collimation (3-4 mm slices): Better for small intraductal stones and fine ductal detail; used alongside the thick-slab for completeness
• 3D MIP (Maximum Intensity Projection) reconstruction: Post-processing of thin-slice images creates 3D maps of the biliary tree and pancreatic duct

Hepatobiliary Contrast-Enhanced MRCP

• These agents shorten T1 relaxation and are excreted via hepatocytes into bile (biliary phase begins 10-30 minutes post-injection)
• T1-weighted sequences provide functional information in addition to anatomical detail
• Particularly useful for detecting biliary leaks, variant anatomy, and small liver metastases in the hepatobiliary phase
• Requires near-normal hepatocyte function for adequate biliary excretion

Indications for MRCP

MRCP Findings in Common Surgical Conditions

Advantages of MRCP

1. Non-invasive - no endoscopic access, no radiation, no ductal contrast injection
2. No ionizing radiation - safe in pregnancy (ERCP in pregnancy carries fetal radiation risk)
3. No sedation or anaesthesia required in most cases
4. No risk of post-procedure pancreatitis (the most feared ERCP complication)
5. Images both sides of a complete obstruction - ERCP can only show ducts distal to total obstruction; MRCP shows both the proximal and distal biliary tree
6. Can be combined with conventional MRI - evaluates periductal structures, hepatic parenchyma, vascular anatomy, lymph nodes in one examination (ERCP cannot)
7. Useful in altered anatomy - Roux-en-Y, Billroth II, hepaticojejunostomy - where ERCP access is impossible or technically very difficult
8. No operator-dependent failure - unlike ERCP which fails in 5-10% due to unsuccessful cannulation
9. Excellent sensitivity/specificity - for choledocholithiasis: sensitivity >90%, specificity ~99%

Limitations and Disadvantages of MRCP

MRCP vs ERCP - Comparison

MRCP in Surgical Decision Making

1. Choledocholithiasis workup before cholecystectomy:
   • Low risk patients: proceed to laparoscopic cholecystectomy with intraoperative cholangiogram
   • Intermediate risk: MRCP first - if CBD stone confirmed, pre-operative ERCP + stone clearance then cholecystectomy; if negative, proceed directly to cholecystectomy
   • High risk (cholangitis, dilated CBD >8 mm): proceed to ERCP directly
2. Suspected cholangiocarcinoma: MRCP + MRI defines Bismuth classification, vascular involvement, and resectability - guides decision between resection, transplant, or palliation
3. Pre-hepatectomy biliary mapping: MRCP defines variant biliary anatomy (right posterior sectoral duct draining into CHD, trifurcation) to prevent inadvertent ductal injury during liver resection
4. Post-cholecystectomy bile leak/injury: MRCP characterizes the level and type of bile duct injury (Strasberg classification) before surgical repair planning
5. Acute biliary pancreatitis: MRCP detects persistent CBD stone to determine if ERCP is needed

Conclusion

• Bailey and Love's Short Practice of Surgery, 28th Edition
• Sabiston Textbook of Surgery, 21st Edition (MRCP, Choledocholithiasis)
• Mulholland & Greenfield's Surgery, 7th Edition
• Yamada's Textbook of Gastroenterology, 7th Edition (MRCP of Biliary System)
• Grainger & Allison's Diagnostic Radiology (Biliary Imaging)