Nonsurgical therapy of gallstones: implications for imaging

Morphological and demographic associations of biliary symptoms in subjects with gallstones: findings from a population-based survey in Rosario, Argentina

BACKGROUND

Gallstone disease is a frequently encountered disorder in subjects living in Rosario. The reasons for the presence or absence of symptoms are unknown.

AIMS

To determine associations between biliary symptoms and ultrasonographic features of gallbladder and gallstones.

SUBJECTS

A random study was conducted on 1,173 subjects, inhabitants of 20 years and older, in the city of Rosario, Argentina.

METHODS

High-resolution abdominal ultrasound examinations were performed. Biliary pain was defined based on previously published definitions.

RESULTS

Gallstones were found in 149 subjects (101 female, 48 male) of whom 51% of females and 35% of males with cholelithiasis were symptomatic. Mean age was 53 years in symptomatic and 55 in asymptomatic subjects. Gallbladder size was normal in 97% of symptomatic and in 96% of the asymptomatic participants. There were no significant differences between the groups as far as concerns size and gallstone number. Impacted stones were observed in 10% of symptomatic and in none of the asymptomatic subjects (p<0.01).

CONCLUSIONS

Subjects' age and gender, gallstones size and number, as well as ultrasonographic features of gallbladder and biliary tract did not differ significantly between symptomatic and asymptomatic subjects. Only impacted stones were significantly more frequent in symptomatic subjects.

Biliary tract imaging

In addition to the detection of gallstones, common bile duct stones, and narrowed and dilated bile ducts, recent advancements in imaging techniques now make it possible to diagnose microlithiasis, pathology of normal-size ducts, and dysfunction of the gallbladder and the sphincter of Oddi (SO). More and more frequently, noninvasive imaging techniques obviate the risk of invasive investigation. These techniques can also take the place of unsuccessful or contraindicated direct cholangiography, and they play an essential role in treatment planning and diagnosis of postoperative complications. Transabdominal ultrasonography (TUS) remains fundamental for initial assessment of the biliary tract. Technical developments make magnetic resonance cholangiopancreatography the most promising diagnostic technique of the biliary tract. Endoscopic ultrasonography (EUS) is most helpful for detection of microlithiasis and evaluation of the ampullary region, the periductal structures, and the regional lymph nodes in neoplastic diseases. Cholescintigraphy is most valuable to assess bile dynamics in the diagnosis of gallbladder and SO dysfunction and in postoperative bile leakage.

Symptomatic versus silent gallstones. Radiographic features and eligibility for nonsurgical treatment

It is unknown whether demography, gallbladder function, or the radiographic appearance of gallstones predispose them to cause symptoms. We investigated these features in a consecutive series of 260 patients with newly diagnosed, uncomplicated gallstone disease, of whom 146 had experienced biliary pain and 114 were asymptomatic. All patients underwent double-dose oral cholecystography and cholecystosonography, and the combined data of these examinations were used to assess gallbladder function and stone number, size, and radiopacity. The gallstones were multiple in 68%, radiolucent in 73%, and in visualized gallbladders in 79% of the 260 patients. The comparison of different variables in patients with and without biliary pain showed that the female gender (P = 0.030; odds ratio 1.86), a family history of gallbladder disease (P = 0.022; odds ratio 1.89), a nonvisualized gallbladder (P < 0.001; odds ratio 3.14), multiple stones (P = 0.036; odds ratio 1.89), and those which were small (P = 0.009; odds ratio 2.08) or of dissimilar size (P = 0.041; odds ratio 1.91) were associated with biliary pain. Women with silent stones had been pregnant more often (P < 0.001, difference between means 1) than those with biliary pain. Gallbladder function and the radiologic characteristics of stones were unrelated to age and gender. Estimates of eligibility for nonsurgical therapies among the 146 symptomatic patients were 44% for bile acid therapy, 16% for lithotripsy, and 56% for methyl tert-butyl ether. In conclusion, some inherent features of gallstones are associated with biliary pain. Whether they have predictive value of future symptom development in subjects with silent stones can be determined by prospective follow up.

Ultrasonic evaluation of gallbladder emptying with ceruletide: comparison to oral cholecystography with fatty meal

Assessment of gallbladder function is required prior to nonsurgical treatment of gallstones. In order to develop a practical and reproducible method of evaluation, gallbladder emptying was studied by ultrasound (US) in 55 gallstone patients after intramuscular administration of ceruletide (0.3 micrograms/kg). In 27 of these subjects, the US procedure was compared to oral cholecystography (OCG) with fatty meal. Maximal percent gallbladder contraction was reached 30 min after ceruletide in all patients. Maximal percent contractions were 47.5 +/- 27.7 during US with ceruletide and 33.9 +/- 16.3 during OCG with fatty meal (p = 0.03). A significant linear relationship was found between the results obtained with the two different procedures (r = 0.57; p = 0.002). Serial US determinations of gallbladder emptying were performed in 16 patients. Individual variation was below 20% in 11 subjects, and in five subjects it ranged between 20 and 40%. Minor, self-limiting side effects were observed in 13 patients. US determination of gallbladder emptying after ceruletide appears to be a practical and reliable method to assess gallbladder function.

Radiographic features of oral cholecystograms of 448 symptomatic gallstone patients: implications for nonsurgical therapy

Since radiographic findings on oral cholecystography (OCG) have implications for the eligibility for nonsurgical therapy of elderly patients, we investigated the OCGs of 448 symptomatic gallstone patients (109 male, 339 female; mean age, 49.8 +/- 14 (range, 21-88)). Opacification of the gallbladder was found in 323 cases (72.1%). Calcifications of gallstones were found in 85 opacified gallbladders (26.3%). Solitary and multiple stones were calcified in 35.3% and 18.2%, respectively (P < 0.0005). When divided into two groups (< or = 40 years and > 40 years), there was a significant increase in calcifications (P < 0.02) and a non-significant increase in opacification with increasing age. It is concluded that age is a determinant for calcification of gallstones and not opacification of the gallbladder. Since multiple stones are proportionately observed more in clinical studies than in epidemiologic studies, it is suggested that multiplicity of stones predisposes to biliary complaints. That solitary stones are more likely to be calcified than multiple stones, adds to the hypothesis that solitary and multiple stones have a different pathogenesis. Elderly patients, in whom non-surgical therapy is most likely to be indicated and cost-effective, are less likely to be suitable for this form of treatment, since age is a determinant for stone calcification.

Radiological aspects of solvent dissolution of gall-stones

Twenty-five patients were referred for solvent dissolution of gall-stones using methyl tertiary butyl ether (MTBE). All patients were assessed beforehand by ultrasound and oral cholecystography. Computed tomography was performed in 23 patients to assess stone calcification and gall-bladder anatomy. Successful stone dissolution was achieved in 15 patients and partial dissolution in six patients. Failure to catheterize the gall-bladder occurred in four patients. There were four biliary leaks, two requiring cholecystectomy. The CT appearances of the gall-bladder may have predicted problems with catheterization in three of the four cases, and the results suggest that cover of the gall-bladder by the liver of greater than 50% is a favourable predictor of successful catheterization. A thick-walled gall-bladder and excess fat between the liver and the lateral abdominal wall are adverse predictors of successful gall-bladder catheterization. Both tubography and ultrasound should be used to assess progress of dissolution. Newer, more effective solvents together with increased expertise in interventional techniques may encourage the more widespread use of solvent dissolution of gall-stones as an alternative to surgery in a selected population.

The value of ultrasound in the follow-up of patients treated with biliary lithotripsy. Implications for monitoring patients after nonsurgical therapy of gallbladder stones

To establish the value of ultrasound (US) in the follow-up of patients treated with extracorporeal shockwave lithotripsy (ESWL), the results of 484 US examinations of 87 patients were analyzed and related to the results of ESWL. Reliability of US in assessing efficacy was investigated by comparing consecutive US examinations. Unreliable US results were found in 36 patients (41%); in 7 patients US failed to demonstrate fragments. In nine patients (10%) unreliable US findings contributed to delayed retreatment with ESWL. To prevent errors in treatment regimen, verification of US findings is advised in case no fragments or fragments < 5 mm are found. In 22 patients (25%) US findings appeared indicative of hampered stone migration. Only 2 of these 22 patients (9.1%) became free of stones, compared with 32 of the remaining 65 patients (49.3%) (p < 0.01), even though both groups had similar initial stone characteristics and similar time of follow-up. US findings such as a contracted gallbladder or a common bile duct > 7 mm therefore indicate poor efficacy of ESWL.

Role of oral cholecystography, real-time ultrasound, and CT in evaluation of gallstones and gallbladder function

The capacity of oral cholecystography (OCG), real-time ultrasound (RUS), and computed tomography (CT) to detect gallstones and to analyze their size, number, and composition was tested preoperatively in 37 patients undergoing elective cholecystectomy. Gallbladder response to a standard meal was also evaluated by OCG and RUS. Gallstones were analyzed chemically for calcium, cholesterol, and bilirubin content. The results show that RUS is the most valuable test for detecting gallstones and is similar to OCG in measuring their size and number, whereas CT underestimates the stone size. Gallbladder function in terms of contractibility can be evaluated by RUS and OCG, but RUS provides useful information even if the gallbladder is not opacified at OCG. CT is more accurate than OCG in detecting the presence of calcium, and CT attenuation numbers are positively correlated with calcium content of the stone (r = 0.87, p less than 0.01).

Accuracy of ultrasound and oral cholecystography in assessing the number and size of gallstones: implications for non-surgical therapy

Prior to non-surgical therapy of gallstones it is important to assess their number and size. In order to evaluate the accuracy of ultrasound (US) and oral cholecystography (OCG) in counting and measuring gallstones, a prospective blind study was conducted to compare the results of US (n = 99) and OCG (n = 36), either alone or in combination (n = 34), with the number and size of gallstones retrieved after cholecystectomy. The number of gallstones was accurately estimated by US and OCG in 74% and 69% of the cases, respectively. In assessing the presence of up to three, five or 10 gallstones both US and OCG proved reliable. In measuring the size of gallstones, there was 19% accuracy with US compared with only 3% with OCG. With an accepted measurement error of 3 mm these values increased to 80% for US and 44% for OCG. US proved more reliable than OCG in discriminating gallstones smaller or larger than 10 mm and smaller or larger than 20 mm, but with US, detection of gallstones larger than 30 mm was problematic. Both US and OCG underestimated gallstone size. The combination of both techniques did not significantly improve the assessment of either number or size of gallstones compared with the results obtained with US or OCG alone. It is concluded that (1) both US and OCG have some limitations in assessing the number and size of gallstones, (2) the combination of both examinations does not improve accuracy, and (3) patient selection for non-surgical treatment of gallstones can be started by US alone.

The value of sonography in determining cystic duct patency

A prospective blinded comparison of ultrasonography (US) and oral cholecystography (OCG) was performed in 100 patients with symptomatic gall-stones to determine whether US would enable an accurate assessment of cystic duct patency to be made. Patency of the cystic duct was defined as gall-bladder opacification on OCG or a greater than 20% decrease in gall-bladder volume by US post-fatty meal. The ellipsoid method of volume measurement was used. Any patient who had a non-opacified gall-bladder on OCG but a greater than 20% volume decrease on US had cholescintigraphy performed (DISIDA). Oral cholecystography demonstrated cystic duct patency in 88 patients (88%), and fatty-meal gall-bladder US met the specified study criteria for patency in 86 patients (86%). False negative results were identified in four of the OCG and in six of the US examinations. The results of this study indicate that gall-bladder sonography with a post-fatty meal contraction of greater than 20% is a very accurate predictor of cystic duct patency. A contraction of less than 20%, however, cannot be considered a reliable predictor of cystic duct occlusion.

Cholelithasis

Extracorporeal shock wave lithotripsy (ESWL) is one nonsurgical method available to treat cholelithiasis. Optimal imaging of gallstones is crucial in assessment and treatment using ESWL. The purpose of this study was to see if placing the patient in the left anterior oblique (prone with the right side elevated) position, rotating the patient 360°, or doing both of these things made it easier to visualize and measure gallstones during ultrasound examination of patients both before and after lithotripsy. There was improvement in stone visualization in 29% of the cases in this study when one or the other of these positions was used.

Pathophysiology and pharmacotherapy of cholelithiasis

Several factors are involved in the development of gallstone formation: formation of supersaturated bile; nucleation; formation, retention and adhesion of cholesterol crystals and eventually stone growth. The dynamics of the gallbladder may play a key role in the overall process. The pathophysiologic theory of cholesterol gallstone formation and the knowledge of their physico-chemical properties support the modern concept of gallstone therapy. Chenodeoxycholic and ursodeoxycholic have been widely used as cholesterol gallstone dissolving agents and evaluated in terms of efficacy and safety.

Accuracy of ultrasound in counting and measuring gallstones

A prospective study of accuracy of ultrasound in measuring and counting gallstones was undertaken in 30 patients undergoing cholecystectomy. Stones were correctly counted (up to five) in 27 of 30 patients. Ninety-three of 106 stones (88%) examined were measured accurately (with a 2 mm error margin). The size of the smaller stones tended to be overestimated, whereas the size of the larger stones tended to be underestimated. When nonoperative treatment of gallstones is considered, ultrasound can be used as the first examination to identify patients who will not be eligible for one or another protocol on the basis of size or number of stones.

Ultrasonic evaluation of gallbladder function prior to non-surgical treatment of gallstones

A comparative analysis of ultrasonic and oral cholecystographic assessment of gallbladder function in symptomatic patients with cholelithiasis is presented. Ultrasonic evaluation demonstrated non-contractile gallbladders in all but one patient with non-opacification during oral cholecystography, whereas all those opacifying on oral cholecystography contracted on ultrasonography. Both techniques showed similar abilities to quantify the size and number of biliary calculi within the limits necessary to determine suitability for treatment. Although computed tomography remains necessary to quantify gallstone density prior to non-surgical treatment, ultrasonography is a safe, acceptable, cheap and preferable alternative to oral cholecystography in assessing gallbladder function.

The value of ultrasound in predicting non-visualization of the gall-bladder on OCG: implications for imaging strategies in patient selection for non-surgical therapy of gallstones

Gall-bladder visualization on oral cholecystography (OCG) is required for most non-surgical therapies of gallstones. In this study we attempted to establish sonographic criteria which will predict non-visualization of the gall-bladder on OCG. For this purpose we compared the results of ultrasound (US) and OCG in 171 patients with gallstones being assessed for non-surgical therapy. Sonographic criteria for non-visualization were a contracted gall-bladder and stone impaction in the gall-bladder neck or cystic duct. In detecting findings which predict non-visualization on OCG, US had a sensitivity of 78.3% and a specificity of 97.6%. The predictive values were: positive findings 92.3% and negative findings 92.4%. The overall accuracy was 92.4%. We conclude that US can be used as a first step in selecting patients for non-surgical therapy and if US indicates a contracted gall-bladder, 11% of the patients can be excluded from further diagnostic imaging.

Gallstone dissolution by methyl-tert-butyl ether (MTBE) via percutaneous transhepatic cholecystostomy

Dissolution of gallbladder stones with MTBE appears to be an effective and safe treatment for patients with symptomatic gallstones who are unfit for surgery. However, the procedure is tedious and the stone recurrence rate is as yet unknown.