Pancreatic Imaging

Pancreatic Anatomy & Modalities - Gland Essentials

• Anatomy: Mostly retroperitoneal.
  • Parts: Head (in duodenal C-loop), Uncinate, Neck (anterior to SMV/PV confluence), Body, Tail (intraperitoneal, to splenic hilum).
  • Ducts: Main (Wirsung), Accessory (Santorini).
• Imaging Modalities:
  • USG: Initial, often gas-limited.
  • CT: Primary tool. IV contrast phases: Pancreatic (~35-45s), Portal Venous (~60-70s).
  • MRI/MRCP: Ducts, cystic lesions, problem-solving.
  • EUS: High-resolution imaging, staging, biopsy (FNA).
  • ERCP: Ductal diagnosis & intervention.

⭐ The uncinate process of the pancreas hooks posterior to the Superior Mesenteric Vein (SMV) and Superior Mesenteric Artery (SMA).

Acute Pancreatitis - Inflamed Insights

Sudden pancreatic inflammation.

• Etiology: 📌 I GET SMASHED: Idiopathic, Gallstones, Ethanol, Trauma, Steroids, Mumps, Autoimmune, Scorpion sting, Hypercalcemia/Hyperlipidemia, ERCP, Drugs.
• Imaging: Diagnose, find cause, grade severity, spot complications.
  • USG: Initial; gallstones, biliary dilatation.
  • CECT: Gold standard for severity, complications. Best at 48-72 hrs for necrosis.
    • Balthazar Score (A-E): Inflammation grade.
    • Necrosis: <30%, 30-50%, >50%.
  • MRI/MRCP: Problem-solving, ductal view, suspected CBD stones.

• Complications: Fluid collections, pseudocyst, abscess, necrosis, pseudoaneurysm.

⭐ The CT Severity Index (CTSI), combining Balthazar grade with the extent of pancreatic necrosis (0, <30%, 30-50%, >50%), is crucial for prognosticating acute pancreatitis.

Chronic Pancreatitis - Scarred Stories

• Irreversible pancreatic damage: fibrosis, atrophy, calcification.
• Key Etiologies: Alcohol (MC), idiopathic, genetic, autoimmune.
• Imaging Hallmarks:
  • CT (NCCT best for calcifications):
    • Parenchymal/intraductal calcifications.
    • Ductal dilatation ("chain of lakes" sign).
    • Pancreatic atrophy.
    • Pseudocysts.
  • MRCP: Ductal strictures, dilatation, side-branch ectasia.
  • EUS: Early parenchymal/ductal changes (lobularity, strands).

⭐ Pancreatic calcifications, best seen on non-contrast CT, are a hallmark of chronic pancreatitis, often appearing as 'chain of lakes' when intraductal.

• Complications: Pseudocysts, vascular (pseudoaneurysm, thrombosis), biliary stricture, ↑cancer risk.

Pancreatic Neoplasms - Tumor Telltales

• Pancreatic Ductal Adenocarcinoma (PDAC): Most common (~90%).
  • Imaging: Ill-defined, hypovascular mass.
  • Key sign:

    ⭐ The 'double duct sign' (co-existing dilatation of both the common bile duct and the pancreatic duct) on CT or MRCP is highly suggestive of a pancreatic head malignancy, most commonly ductal adenocarcinoma.

  • Vascular encasement (celiac, SMA, PV) → unresectable.
  • Mets: Liver, nodes.
• Pancreatic Neuroendocrine Tumors (PNETs):
  • Well-defined, hypervascular.
  • Insulinoma: Small (<2 cm), hypervascular. Gastrinoma: MEN-1.
• Cystic Neoplasms:

• Solid Pseudopapillary Neoplasm (SPN):
  • Young females; large, encapsulated, mixed solid-cystic. Low malignant potential.

High‑Yield Points - ⚡ Biggest Takeaways

• CECT is modality of choice for acute pancreatitis and its complications (e.g., pseudocysts, necrosis).
• MRCP excels for pancreaticobiliary ducts, choledocholithiasis, and ductal anomalies without radiation.
• Pancreatic adenocarcinoma: typically hypodense mass in pancreatic head on CECT; causes double duct sign.
• Chronic pancreatitis: key findings are calcifications, ductal dilatation, and parenchymal atrophy.
• ERCP is gold standard for therapeutic interventions in biliary and pancreatic ductal issues.
• Autoimmune pancreatitis: often shows sausage-shaped pancreas with a delayed enhancing capsule-like rim.