HEPATOBILIARY AND PANCREAS IMAGING🗸

Condition	Segments Seen	Image Reference
Kidney seen	3, 4b, 5, 6	Image 1
Kidney not seen	2, 4a, 8, 7	Image 2

 

• Three hepatic veins present
• Drain into IVC

• Portal vein division
• Upper half: Segments 2, 4a, 8, 7
• Lower half: Segments 3, 4b, 5, 6

 

Fissures:

• Major (3):
• LHV, MHV, RHV

• Minor (3):
• LPV, RPV, Fissure of Ganz.

• 4 Sectors: (Sections)
• 6 and 7
• 5 and 8
• 4a and 4b
• 2 and 3

• Recent Update:
• Division based on:
• Portal vein > Hepatic vein > Bile duct > Hepatic artery

Cantlie's Line:

• middle line by Middle hepatic vein

• Joins IVC to Gallbladder (MHV location).

• Divides the liver into R and L functional lobes.

Segment Significance:

USG DVT

• Distended vein which is non compressible

• Normal vein is compressed

Mickey Mouse Sign

• In the groin region - saphenofemoral junction:
• Femoral vein.
• Femoral artery.
• Great saphenous vein.
• Note: Profunda femoris not part.

Portal triad / Liver Pedicle:

 

• Contents: Hepatic vein is not at the portal triad.
• Portal vein (Larger)
• CBD
• Hepatic artery

• Duplex scan: Mickey Mouse sign.

• Largest vein supplying the liver: portal vein.

• Adjacent smaller one: hepatic artery.

• Behind the portal vein: inferior vena cava.

Portal vein

• Portal vein has a monophasic waveform.

• There is no negative flow.

• There is always forward flow above the baseline.

Cystic Lesions of the Liver

Simple Cyst: (Image 1)

• Cystic lesions contain water

• They appear gray on CT.

• The cyst has a thin wall.

Liver Abscess: (Image 2)

• An abscess has a thick wall.
• This is due to inflammation and granulation tissues.

• History of dysentery followed by abscess:
• Amoebic liver abscess

Central dot sign: (Image 3)

• A lesion in the liver with a central dot.

• Seen in Caroli's disease,
• Type 5 choledochal cyst

Layers of hydatid cyst

• Echi → Casino (casoni) ilu chuuthu kalich → 5 alkk (5 Arc) paisa kodukkkanam → Olichirun (Hide - hydatid cyst) → in water lillyy → Dog ne bite cheyyich → first liver then lungs

Classification (WHO-IWGE 2001 / Gharbi 1981 USG based):

• Echinococcus granulosus → Granny kk ekkili eduthu (Echinococcus gran) → CBSE 3rd std Appu (3a) → 2 (Type2) Lilly (water Lilly) kondu koduthu

Treatment of Echinococcus granulosus

• First line: Albendazole

• PAIR Process:
• P - Puncture of cyst.
• A - Aspirate.
• I - Injection scolicidal agent
• R - Re-aspiration.

• Scolicidal agents:
• Hypertonic saline (M/c),
• Cetrimide,
• Mebendazole
• Alcohol.
• Note: Formalin not used (causes chemical cholangitis).

• Contraindications (C/I) for PAIR:
• 4 and 5
• Cystobiliary communication
• During aspiration, if bilirubin level positive
• DO NOT INJECT SCOLICIDAL AGENT
• Dead cyst, Calcified cyst, Extrahepatic cyst.
• Deep seated, Multiloculated.

• Surgery: 
• Done if PAIR is C/I
• Liver resection or cystopericystectomy

Echinococcus multilocularis:

• Multilocular AKA alveolar hydatid cyst.

• M/C site: Liver.

• Second M/C site: Lungs.

Triple phase CT: IOC

• LIRADS score.
• Procedure:
• A plain scan is taken first.
• IV contrast is given.
• Timings of the scan's images are noted.
• Phases Finding:







• Non-contrast: Hypodense.
• Arterial: Enhancement → (Hepatic A supply)
• Venous: Early washout.
• Delayed phase: Capsule
• Note:
• Differentiates Hemangiomas and HCC.
• Metastasis on triple phase CT:
• All phases hypodense.
• Underlying cirrhosis
• Indicated by:
• Irregular surface of the liver.
• Ascites.

Gall Bladder

• Gall bladder
• Appears black due to bile

• Echogenic structure
• Gall stones → posterior acoustic shadowing (+)

Phrygian Cap:

• Folding inside gallbladder

• Considered normal

• Physiological variant.

• Not an indication for cholecystectomy or risk for cancer.

Porcelain GB

• Premalignant - 10%

Strawberry Gallbladder:

• Cholesterolosis of the gallbladder 

• aka Adenomyomatosis of gall bladder

• Note: Cholesterosis (Strawberry GB) is not a risk factor for GB cancer

• Gross specimen: 
• Strawberry GB appearance

• White lines → Comet tail appearance

• Special Stains: 

Stains	Sections For	Features
Oil Red O (reddish)	Frozen/Fresh section	For fat identification Advantage Tissue frozen → no chemicals added → fat preserved. (Routine processing alcohol washes off fat).
Sudan Black B (black)	Fixed	ㅤ
Sudan 4 (orange)	ㅤ	ㅤ

Gallbladder Poly

• Appears attached to gallbladder wall and echogenic

• No posterior acoustic shadowing

• Non‑mobile

Gall Stone

• Posterior acoustic shadowing

• Mobile

• GB stone in CT
• Usually not seen
• When seen → Mercedes Benz sign
• Stone with trapped air inside

Tokyo Guidelines for Diagnosis:

• a. Local signs of inflammation:
• Murphy’s sign
• RUQ pain/tenderness/mass + N/V

• b. Systemic signs of inflammation:
• Fever
• ↑ CRP
• ↑ WBC

• c. Imaging findings: IOC → US
• Overdistended gall bladder
• Probe tenderness
• Thick wall (> 3 mm)
• Pericholecystic fluid.
• Gallbladder stone in the neck causing obstruction

• Suspected diagnosis:
• 1 item in A & B but not C.

• Definitive diagnosis:
• 1 item in A + B + C.

• Gold standard investigation
• For acalculous cholecystitis.
• HIDA scan

HIDA Scan

• Tests for the biliary tract

• HIDA shows uptake/excretion in biliary tract
• HIDA enters biliary tract
• Blocked gallbladder → HIDA will not enter
• Leads to non-visualisation of gall bladder
• HIDA = nuclear scan for biliary tract

Inference

• Presence in gallbladder, biliary tract, duodenum, intestine
• Patent biliary tract

• Biliary atresia:
• HIDA not seen in biliary tract

Grading (Tokyo consensus guidelines):

Management (Based on Tokyo guidelines):

• Note: Chronic cholecystitis → Mx: Cholecystectomy.

• Grade I: 
• Antibiotics + General supportive care.
• Early laparoscopic cholecystectomy (LC).

• Grade II & III: 

Emphysematous cholecystitis

 

• Black on CT is air.

• Air means Emphysema.

• This is emphysematous cholecystitis.

Strawberry Gallbladder:

• Cholesterolosis of the gallbladder 

• aka Adenomyomatosis of gall bladder

• Note: Cholesterosis (Strawberry GB) is not a risk factor for GB cancer

• Gross specimen: 
• Strawberry GB appearance

• White lines → Comet tail appearance

• Special Stains: 

CECT: IOC

• The pancreas appears bulky.

• Seen in Acute pancreatitis.

• CECT helps differentiate necrotising and non-necrotising pancreatitis.
• With contrast → necrotic areas will not enhance (they are dead).
• Should be done after 72 hours for necrosis to set in.

CT Criteria for Pancreatitis

• Severity of pancreatitis is graded by CTSI score (CT severity index).

• CT severity index/Balthazar grading ≥6: 
• Best scoring system

IOC: CECT

• Fluid is gray with a wall.

X-ray Acute Pancreatitis:

• Colon cutoff sign
• abrupt termination of gas within the proximal colon
• d/t functional spasm of infiltrating phrenicocolic ligament
• Suggest Localised Inflammation from the pancreas
• → spreads to the splenic flexure.
• → functional spasm/paralysis of the colon.

• Sentinel loop sign
• Early indicator of A/c Pancreatitis on Xray
• Isolated prominent bowel loop.
• Seen adjacent to the inflamed organ.

• Gasless abdomen

• Features:
• Atrophic pancreas (fibrosis, shrinkage).
• Dilated pancreatic duct.
• Calcifications.
• Chain of lakes appearance.

• Peripancreatic fluid accumulation is not seen.

• First image:
• Pancreatic calcification.
• Chronic pancreatitis

• Second image:
• Atrophic pancreas with calcification.
• MRCP shows a dilated pancreatic duct.
• Beaded pancreas with chain of lakes appearance.

• MRCP: Double duct sign

• First image
• Dilated CBD + Pancreatic duct
• Open at ampulla of Vater
• Seen in Periampullary carcinoma / Pancreatic head carcinoma

• Second image
• Pancreatic head mass
• pulls duodenal wall
• loss of C curve
• C loop widening
• reverse 3 sign