PROSPECTIVE, MULTICENTER STUDY ON VALUE OF COMPUTERIZED-TOMOGRAPHY (CT) IN GALLSTONE DISEASE IN PREDICTING RESPONSE TO BILE-ACID THERAPY

The aim of the study was to assess the value of quantitative attenuati on values (Hounsfield units) and of gallstone pattern by computerized tomography in predicting response to bile acid therapy. We carried out a prospective study in a multicenter setting on 90 consecutive outpat ients with radiolucent gallstones. All received bile acid therapy (UDC A 10 mg/kg/day or UDCA + CDCA 5 mg/kg/day of each) up to two years. Ho unsfield units for gallstones were recorded using standardized criteri a and six categories of patterns were defined: hypodense, isodense, ho mogenously dense, laminated, rimmed and speckled. We assessed gallston e dissolution rate (percent reduction in volume), response to therapy (>25% reduction in volume), and final outcome of therapy. Eighty-one p ercent of patients with hypodense/isodense and all four patients with speckled stone pattern responded to therapy, whereas none of the 10 pa tients with laminated/rimmed and only 45% of patients with homogenousl y dense stone pattern did. Complete dissolution was achieved by 68%, 5 0%, 35%, 0% of the hypodense/isodense, speckled, homeogenously dense, rimmed/laminated gallstones, respectively. The use of Hounsfield units did not show an advantage over gallstone pattern for predicting eithe r response or final outcome to bile acid therapy. We conclude that com puterized tomography analysis of gallstones is of value in predicting response to bile acid therapy and that gallstone pattern alone predict s response in most cases without the need for quantitative assessment.