Gallbladder enhancement following angiography: a normal CT finding

Clinical analysis of contributors to the delayed gallbladder opacification following the use of water-soluble contrast medium

OBJECTIVES

Gallbladder opacification (GBO) on computed tomography (CT) imaging may obscure certain pathological or emergent conditions in the gallbladder, such as neoplasms, stones, and hemorrhagic cholecystitis. This study aimed to investigate the clinical contributing factors that could predict the presence of delayed GBO determined by CT.

METHODS

This study retrospectively evaluated 243 consecutive patients who received enhanced CT or intravenous pyelography imaging and then underwent abdominal CT imaging within 5 days. According to the interval between imaging, the patients were divided into group A (1 day), group B (2 or 3 days), and group C (4 or 5 days). Three radiologists evaluated CT images to determine GBO. Fisher's exact test and multivariate backward stepwise elimination logistic regression were performed.

RESULTS

Positive GBO was significantly associated with the interval between imaging studies, contrast type, contrast volume, renal function, and hypertransaminasemia (P<0.05). Multivariate backward stepwise elimination logistic regression analysis of the three groups identified contrast type and hypertransaminasemia as independent predictors of GBO in group B patients (odds ratio [OR], 13.52, 95% confidence interval [CI], 1.72-106.38 and OR, 3.43, 95% CI, 1.31-8.98, respectively; P<0.05). Hypertransaminasemia was the only independent predictor of GBO in group C patients with an OR of 7.2 (95% CI, 1.62-31.73). Hypertransaminasemia was noted in three patients (100%) who initially underwent imaging 5 days prior to GBO.

CONCLUSION

Delayed GBO on CT imaging may be associated with laboratory hypertransaminasemia, particularly in patients receiving contrast medium over a period of ≥4 days. A detailed clinical history, physical examination, and further workup are of paramount importance for investigating the underlying cause behind the hypertransaminasemia.

Computed tomography evaluation of high-density bile in the gallbladder

On computed tomograms obtained during a seven-year period, 27 patients were found to have high-density bile in the gallbladder. Serial computed tomography (CT) examinations showed that gradual narrowing of common bile duct is a causative factor. This has not been reported previously. The density of the bile in the gallbladder of patients with such obstruction was almost equal to that of normal liver on CT. In some of the patients in whom obstruction of the cystic duct was the factor of high-density bile and continued for a long time, the density of the bile decreased and hydrops developed.

Contrast-enhanced computed tomography of the normal and abnormal gallbladder

One hundred and fourteen upper abdominal computed tomography examinations performed before and after intravenous contrast were reviewed. In 48 patients who had no evidence of biliary or pancreatic disease, the mean gallbladder wall attenuation before contrast was 25 +/- 13 HU and after contrast 42 +/- 18 HU, with a wall thickness of 1.9 +/- 0.43 mm. In 14 patients with chronic pancreatitis these values were 24 +/- 10.5 HU, 44 +/- 25 HU and 2.0 +/- 0.54 mm, respectively. In a further group of 15 patients with chronic biliary disease, the values were 34 +/- 15 HU, 53 +/- 18 HU and 2.3 +/- 0.9 mm. The degree of wall enhancement was statistically significant in each group. There was no statistical difference in the attenuation characteristics or wall enhancement between normal patients and those with chronic pancreatitis. Patients with chronic biliary disease had a thicker gallbladder wall with higher attenuation before contrast but a similar degree of enhancement.