Gallbladder torsion (volvulus) is axial rotation of the gallbladder along its mesentery or peritoneal attachments, resulting in twisting and obstruction of the cystic artery and cystic duct. It is rare but requires emergent surgery (100% mortality without intervention). Typically occurs in elderly, thin women — age-related loss of peritoneal fat and increased gallbladder mobility (wandering/floating gallbladder) are predisposing factors. Clockwise or counterclockwise rotation of the gallbladder fundus >180° causes vascular compromise — venous return is obstructed first (congestion, edema, hemorrhage), followed by arterial flow cessation (ischemia, gangrene, necrosis). Preoperative diagnosis is difficult (<10% cases) and is usually discovered intraoperatively in patients taken to surgery with a presumptive diagnosis of acute cholecystitis. On CT, the 'whirl sign' (twisting pattern of the cystic duct and vascular pedicle), diffuse gallbladder wall thickening, and pericholecystic fluid are pathognomonic. On US, echogenic debris within the gallbladder lumen and wall edema (double-wall sign) are seen; Doppler shows decreased or absent wall vascularity.
Age Range
60-95
Peak Age
75
Gender
Female predominant
Prevalence
Rare
Gallbladder torsion occurs when the gallbladder's attachment to the hepatic bed is anatomically weak. Normally the gallbladder is held in the hepatic fossa by peritoneal attachments. With aging, peritoneal fat loss and connective tissue laxity cause the gallbladder to become freely mobile (wandering gallbladder); this is especially pronounced in gallbladders with a long mesentery. Predisposing factors include visceroptosis, kyphoscoliosis, and rapid weight loss. Torsion typically becomes clinically significant at >180° rotation — low-pressure venous return is obstructed first causing congestion and edema, followed by arterial flow cessation leading to ischemic necrosis. Hemorrhagic infarction develops in the gallbladder wall due to venous congestion — this explains wall hyperdensity on CT and T1 hyperintensity on MRI. The whirl sign represents pedicle twisting of the cystic artery and cystic duct — the spiral pattern is seen on CT as rotational configuration of surrounding soft tissue and vascular structures. Sludge and debris accumulate in the gallbladder lumen due to stasis; inflammatory response creates pericholecystic fluid and fat stranding in adjacent tissues. Absence of wall vascularity on Doppler confirms complete cessation of arterial and venous flow — this finding is critical for differentiation from acute cholecystitis because inflammatory cholecystitis typically shows increased wall vascularity.
Spiral/helical configuration of the cystic duct, cystic artery, and surrounding peritoneal fat tissue rotating together at the gallbladder neck level on CT. It is pathognomonic and the most specific finding of gallbladder torsion. Best seen on thin-section (≤1 mm) CT axial and multiplanar reformats. The severity of twisting and level of vascular compromise varies with degree of rotation (180-720°).
Spiral or twisting pattern at the gallbladder neck and cystic duct region on CT — 'whirl sign'. The cystic artery, cystic duct, and surrounding peritoneal fat tissue rotate together forming a helical configuration. This finding is best seen on axial sections at the level of the gallbladder neck and vascular components are more conspicuous on arterial phase. The whirl sign typically represents 180-720° rotation; the degree of vascular compromise increases with increasing rotation.
Report Sentence
Spiral twisting pattern of the cystic duct and vascular pedicle at the gallbladder neck level ('whirl sign') is identified; consistent with gallbladder torsion (volvulus), emergent surgical evaluation is recommended.
Diffuse and symmetric gallbladder wall thickening in the portal venous phase (>3 mm, typically 5-10 mm). The wall may appear hyperdense on non-contrast series (intramural hemorrhage — due to venous congestion). On contrast phases, wall enhancement is decreased or heterogeneous — ischemic areas show no enhancement while preserved areas enhance. In advanced stages, intramural gas (emphysematous change — gangrene) may be seen. Gallbladder lumen is distended and contents are hyperdense (stasis, debris, hemorrhagic bile). Gallstones are typically absent — an important differentiating clue.
Report Sentence
Diffuse gallbladder wall thickening (__ mm) with heterogeneous enhancement and hyperdense luminal content is seen; no gallstones are identified. Ischemic cholecystitis/torsion should be primarily considered in the differential diagnosis.
Marked displacement of the gallbladder from the hepatic fossa — 'floating gallbladder' or 'wandering gallbladder' finding. In normal anatomy, the gallbladder sits in the fossa between hepatic segments IVb/V. In torsion, the fundus moves away from the liver to a more caudal and medial or lateral position. Coronal and sagittal CT reformats show altered gallbladder long-axis orientation and increased distance from the liver surface. Pericholecystic fluid and fat stranding are present.
Report Sentence
The gallbladder is markedly displaced from the hepatic fossa with altered orientation ('floating gallbladder'); consistent with torsion, emergent surgical evaluation is recommended.
Diffuse wall thickening and double-wall (double contour) appearance on B-mode US — wall edema and intramural hemorrhage. Wall thickness is typically 5-10 mm. A hypoechoic band (edema/fluid) is seen between outer and inner wall layers. Echogenic debris (sludge, hemorrhagic bile, fibrin) accumulates in the gallbladder lumen. Gallstones with posterior acoustic shadow are typically absent — simulating 'acalculous cholecystitis' clinically.
Report Sentence
Diffuse gallbladder wall thickening with double contour appearance on US with dense echogenic debris in the lumen; no gallstones identified. Acalculous ischemic cholecystitis/torsion should be considered.
Color and power Doppler show completely absent or markedly decreased wall vascularity. This finding has high sensitivity for ischemic cholecystitis and is the most valuable Doppler finding for differentiating from inflammatory cholecystitis. In acute inflammatory cholecystitis, wall vascularity is typically increased (hyperemia); in torsion/ischemic cholecystitis, arterial and venous flow is interrupted. Power Doppler is more sensitive to low flows — absence on both techniques strongly supports ischemia.
Report Sentence
No vascularity detected in the gallbladder wall on color and power Doppler; consistent with ischemic cholecystitis/torsion, emergent surgical consultation is recommended.
Hyperintense signal in the gallbladder wall on T1-weighted images — reflects intramural hemorrhage (methemoglobin). Hemorrhagic wall thickening develops due to venous congestion and ischemic necrosis. T1 hyperintensity is conspicuous on pre-contrast series and may be confused with enhancement on post-contrast images — subtraction technique helps differentiation. T1 hyperintense fluid may be seen in the gallbladder lumen due to hemorrhagic bile.
Report Sentence
Hyperintense signal in the gallbladder wall on MRI T1 consistent with intramural hemorrhage; ischemic/gangrenous cholecystitis or torsion should be considered.
Criteria
180-360° rotation. Venous congestion predominant, arterial flow may be partially preserved.
Distinct Features
Decreased but not completely absent vascularity on Doppler. Less conspicuous whirl sign on CT. Spontaneous detorsion may rarely occur.
Criteria
≥360° rotation. Both arterial and venous flow completely interrupted. Acute abdomen presentation.
Distinct Features
Prominent whirl sign, complete Doppler vascularity loss, intramural gas (gangrene), pericholecystic abscess/fluid. High perforation risk. Mortality 100% without intervention.
Criteria
Rotation along the gallbladder long axis — most common type (~85%). Fundus rotates to the opposite side.
Distinct Features
Marked rotation of fundus and neck axis from normal on CT — best evaluated on sagittal reformats. Whirl sign seen at neck level.
Distinguishing Feature
In acute cholecystitis, wall vascularity is INCREASED on Doppler (inflammatory hyperemia); in torsion it is DECREASED or ABSENT (ischemia). Acute cholecystitis typically has gallstones and positive Murphy sign. In torsion, absence of stones, floating gallbladder, and whirl sign on CT differentiate.
Distinguishing Feature
Emphysematous cholecystitis has intramural/intraluminal gas but NO whirl sign. Gallbladder is in normal position. In torsion, gas is a late complication accompanied by floating gallbladder + whirl sign.
Distinguishing Feature
Gallbladder perforation shows wall defect and pericholecystic/subhepatic collection. Perforation is typically a stone complication. In torsion, wall defect is a late complication accompanied by whirl sign + floating gallbladder.
Distinguishing Feature
Gallbladder carcinoma shows irregular wall thickening or intraluminal mass + enhancement. Liver invasion may accompany. In torsion, wall thickening is diffuse and symmetric, enhancement is decreased, and whirl sign is present.
Urgency
emergentManagement
surgicalBiopsy
Not NeededFollow-up
specialist-referralGallbladder torsion is an EMERGENT surgical condition — mortality is 100% without treatment. Emergent cholecystectomy should be performed when diagnosed or strongly suspected. Laparoscopic approach is preferred but conversion to open surgery may be needed if gangrene/perforation is present. Preoperative diagnosis is rare (<10%). Critical radiologist contribution: recognizing whirl sign and floating gallbladder on CT, mentioning torsion possibility in acalculous cholecystitis, and emphasizing absent vascularity on Doppler enables preoperative diagnosis. Mortality: 5-6% with emergent surgery, 20-30% with delayed surgery or perforation.
Gallbladder torsion is a rare condition requiring emergency surgery. Preoperative diagnosis is difficult and often made intraoperatively. Delayed treatment can result in gangrene, perforation, and sepsis. Should be considered in elderly, thin women with acute abdomen.