Diagnostic Ultrasound - Abdomen and Pelvis

Hyperplastic Cholecystosis (Adenomyomatosis)
TERMINOLOGY
Synonyms
• Adenomyomatous hyperplasia, diverticular disease of
gallbladder (GB)
Definitions
• Generic term for nonneoplastic, noninflammatory
proliferative disorders of GB wall
○ Cholesterolosis: Abnormal deposits of triglycerides and
cholesterol esters in subepithelium of GB
○ Adenomyomatosis: Focal or segmental GB wall
thickening due to mucosal proliferation and hypertrophy
of muscularis with invagination of excess mucosa into
thickened muscularis- forming Rokitansky-Aschoff (RA)
sinuses
– These sinuses can contain bile, cholesterol crystals,
sludge, and calculi
• Although classified together, cholesterolosis and
adenomyomatosis have different etiology and clinical
features, and should be considered separate entities
IMAGING
General Features
• Best diagnostic clue
○ Cholesterolosis: Multiple tiny cholesterol flecks, usually
occult on imaging, may cause wall nodularity
○ Adenomyomatosis: Focal or segmental wall thickening
with intramural hyperechoic foci and "comet tail"
reverberation artifacts
• Location
○ Gallbladder wall
– Cholesterolosis: Subepithelial
– Adenomyomatosis: Epithelial and muscularis mucosa
• Morphology
○ Adenomyomatosis: 3 morphological patterns
– Diffuse
– Focal
□ Fundal (adenomyoma): RA sinus forms nodule that
projects into lumen
□ Segmental (hourglass): Circumferential ring divides
GB into separate interconnected compartments
Ultrasonographic Findings
• Grayscale ultrasound
○ Cholesterolosis
– Multiple tiny hyperechoic GB polyps may present as
subtle mural nodules
– Usually < 1 mm in size
– No posterior acoustic shadowing or "comet tail"
artifact
– No evidence of invasion to adjacent liver parenchyma
or regional lymphadenopathy
– May coalesce into cholesterol polyps (4-10 mm in size)
○ Adenomyomatosis
– Focal or diffuse GB wall thickening
– Presence of intramural anechoic foci = dilated sinuses
– Tiny echogenic intramural foci in GB wall, producing V-
shaped or "comet tail" artifacts = debris in sinuses
– Hourglass GB: Focal wall thickening forms ring around
midbody
– Fundal adenomyoma: Smooth intraluminal mass,
usually fundal and solitary
• Color Doppler
○ No significant vascularity
○ "Twinkling" artifacts on Doppler examination associated
with debris in RA sinuses
CT Findings
• CECT
○ Adenomyomatosis
– Thickened GB wall (segmental, diffuse, fundal)
– Cystic nonenhancing spaces within GB wall,
corresponding to intramural diverticula
– Hourglass configuration of GB (segmental type)
– Low sensitivity for small (< 5 mm) polyps
MR Findings
• T2WI
○ "Pearl necklace" sign: Most specific sign of
adenomyomatosis on MR, chain of fluid containing
intramural diverticula
• T1WI C+
○ Sinuses: Nonenhancing, hypointense, within thickened
GB wall
Imaging Recommendations
• Best imaging tool
○ US, MR
• Protocol advice
○ Use high frequency transducer for best visualization of
"comet tail" artifacts and cystic spaces
○ Absence of cystic spaces, echogenic foci, or "twinkling"
artifacts, or presence of internal vascularity should
prompt further investigation to rule out neoplasm
– Always examine adjacent liver for infiltration
– Evaluate presence/absence of regional
lymphadenopathy
DIFFERENTIAL DIAGNOSIS
Gallbladder Carcinoma
• Polypoid mass > 1 cm
• Infiltrative and ill-defined margin
• Increased internal vascularity
• Associated with gallstones in most cases
• Adjacent liver parenchymal invasion and regional
metastatic lymphadenopathy
Adenomatous Polyp
• May mimic focal form of adenomyomatosis
• Usually solitary, 5-15 mm
• Nonmobile, nonshadowing polyp
• Usually avascular or hypovascular
Diffuse GB Wall Thickening
• Related to systemic illness (e.g., hepatitis, cirrhosis,
congestive heart failure, etc.)
• Diffuse GB wall involvement
• Striated hypoechoic appearance
• Lack of "comet tail" artifacts or intramural cystic spaces
Chronic Cholecystitis
• Generalized GB wall thickening
Diagnoses: Biliary System
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