Diagnostic accuracy of imaging modalities in differentiating xanthogranulomatous cholecystitis from gallbladder cancer

Abstract

Background: The aim of this study was to assess the diagnostic performance of radiological imaging in differentiating xanthogranulomatous cholecystitis (XGC) from gallbladder cancer (GBC).

Methods: A retrospective analysis of the radiological imaging performed in patients who had pathologically confirmed XGC or GBC between December 2004 to April 2016 was performed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging modality, and combined imaging modalities were calculated.

Results: A total of 218 patients (XGC =109, GBC =109) were identified; 19 patients received all of abdominal ultrasound (US), contrast-enhanced ultrasound (CEUS), computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET/CT); 21 received four of these imaging examination types; 45 received three examinations; 58 received two examinations; and 75 received only one examination. The sensitivity and specificity of CEUS was 90% and 93%, respectively, higher than abdominal US (80%, 86%), CT (71%, 92%), MRI (75%, 90%), and PET/CT (55%, 90%) (all values respective). The sensitivity, specificity, NPV, and PPV of the US combined with CEUS were 91%, 90%, 94%, and 85%, respectively. Although the specificity of CEUS + CT and CEUS + MRI were 100% and 92%, respectively, the sensitivity of CEUS + CT and CEUS + MRI were both only 67%.

Conclusions: The Abdominal US is not sufficiently accurate to confidently guide clinical practice, and CEUS showed better diagnostic performance than the other imaging modalities in differentiating XGC from GBC. The combination of abdominal CEUS and CT is helpful for differential diagnosis, as it indicates GBC with better specificity and PPV.

Keywords: Cholecystitis; contrast-enhanced ultrasound (CEUS); gallbladder cancer (GBC); perioperative diagnosis.

Figure 1

Flow chart of enrolled patient selection.

Figure 2

Sensitivity, specificity, PPV, and NPV of US, CEUS, CT, MRI, and PET-CT for differentiating XGC. (A) The sensitivity of each imaging modality; (B) the specificity of each imaging modality; (C) PPV of each imaging modality; (D) NPV of each imaging modality. PPV, positive predictive value; NPV, negative predictive value; US, ultrasound; CEUS, contrast-enhanced ultrasound; CT, computed tomography; MRI, magnetic resonance imaging; PET, positron emission tomography; XGC, xanthogranulomatous cholecystitis.

Figure 3

Sensitivity, specificity, PPV, and NPV of US and US + CEUS, CT, MRI and PET/CT. (A) Sensitivity of US and US + CEUS, CT, MRI, and PET/CT; (B) specificity of US and US + CEUS, CT, MRI, and PET/CT; (C) PPV of US and US + CEUS, CT, MRI, and PET/CT; (D) NPV of US and US + CEUS, CT, MRI, and PET/CT. PPV, positive predictive value; NPV, negative predictive value; US, ultrasound; CEUS, contrast-enhanced ultrasound; CT, computed tomography; MRI, magnetic resonance imaging; PET, positron emission tomography; XGC, xanthogranulomatous cholecystitis.

Figure 4

Sensitivity, specificity, PPV, and NPV of CEUS, CEUS + CT, CEUS + MRI, and CT + MRI. (A) Sensitivity of CEUS, CEUS + CT, CEUS + MRI, CT + MRI; (B) specificity of CEUS, CEUS + CT, CEUS + MRI, and CT + MRI; (C) PPV of CEUS, CEUS + CT, CEUS + MRI, and CT + MRI; (D) NPV of CEUS, CEUS + CT, CEUS + MRI, and CT + MRI. PPV, positive predictive value; NPV, negative predictive value; US, ultrasound; CEUS, contrast-enhanced ultrasound; CT, computed tomography; MRI, magnetic resonance imaging; PET, positron emission tomography; XGC, xanthogranulomatous cholecystitis.

Figure S1

A 71-year-old male with clinical suspicion of gallbladder carcinoma. The post-operative histopathology was XGC. (A) The anterior gallbladder wall was regularly thickened, while the posterior wall could not be displayed due to the shadow of the cholecystolithiasis on gray scale ultrasound. The boundary between the gallbladder and peripheral liver parenchyma was clear (arrow); (B,C,D) after the injection of contrast agent, the thickened gallbladder wall showed hyper-enhancement in the arterial phase (B) and washout in the portal (C) and late phases (D). The continuity and integrity of gallbladder serous layer was demonstrated on enhanced images (arrow). XGC, xanthogranulomatous cholecystitis.

Figure S2

A 68-year-old male with clinical suspicion of gallbladder carcinoma. The post-operative histopathology was GBC. (A) CUS image: a hypoechoic lesion was detected in the gallbladder area, and the gallbladder wall was not clear; (B) color Doppler ultrasound detected blood flow signals in the gallbladder wall; (C,D) dual-mode images (CEUS on left and CUS on right): the gallbladder wall was enhanced, a hyper-enhancement lesion was seen in the gallbladder cavity which could not be detected on CUS (arrows in image D), and the inner and outer wall were still blurred on CEUS. CEUS, contrast-enhanced ultrasound; GBC, gallbladder cancer.