Clinical efficacy of intravenous morphine administration in hepatobiliary imaging for acute cholecystitis

Revisiting morphine-augmented hepatobiliary imaging for diagnosing acute cholecystitis: the potential pitfall of high false positive rate

Purpose

The aim of this retrospective study was to investigate the efficacy of morphine-augmented hepatobiliary imaging (MAHBI) for diagnosing acute cholecystitis (AC).

Methods

Sixty-eight patients (Male:Female = 36:32, age = 54 ± 17 years) referred for diagnosis of AC by 30-min post-morphine MAHBI after the standard 1-h imaging were recruited. Non-visualization of gallbladder on 30-min post-morphine images by visual analysis was considered positive. Final diagnosis of pathological examination for all patients was used as the gold standard.

Results

There was significant correlation of AC and MAHBI (p < 0.05). There were 45 true positive (TP), 19 false positive (FP), 4 true negative (TN), and no false negative (FN) cases using gallbladder visualization by 30-min post-morphine as the criteria, with a high false positive rate of 83%. The sensitivity, specificity, accuracy, positive and negative predictive values of MAHBI in detecting AC were 100%, 17%, 72%, 70%, and 100%, respectively.

Conclusions

MAHBI is sensitive but may not specific for diagnosing AC due to the potential pitfall of high false positive rate. Correlation with other clinical findings is recommended for optimal patient management.

Nuclear medicine tests for acute gastrointestinal conditions

Acute cholecystitis (AC) and lower-gastrointestinal (GI) bleeding are 2 emergencies commonly encountered in nuclear medicine. Evidence of AC on hepatobiliary scintigraphy (HBS) allows for confident diagnosis and provides support for definitive surgical treatment. Proper patient preparation is essential for HBS including fasting and the use of pharmacologic adjuncts is sometimes required. Pharmacologic adjuncts may also be administered during HBS to shorten the length of the examination and increase its specificity. In the interpretation of HBS, there are several sources of false-positive results to be aware of, most commonly chronic cholecystitis. False-negative results on HBS are usually the result of mistaking another structure, such as a dilated cystic duct, for the gallbladder. Abdominal ultrasound is the appropriate initial test in patients with suspected AC, but HBS is an excellent second tier test for the diagnosis of AC in the work-up of indeterminate cases by sonography. GI bleeding scintigraphy plays an important role in the evaluation and management of patients with acute lower-GI bleeding. Scintigraphy serves to localize sites of active GI bleeding and stratify those patients who would benefit from aggressive treatment (surgery or arteriography) vs those who can be managed medically. Pretest involvement of respective services is critical for successful bleeding site confirmation and therapy by interventional radiology or surgery or both. Single photon emission computed tomography/computed tomography erythrocyte scintigraphy has demonstrated superior accuracy and precision over planar scintigraphy in the diagnosis of acute GI bleeding. Additionally, single photon emission computed tomography/computed tomography scintigraphy of GI bleeding provides useful supplemental anatomical information that benefits patient management.

Hepatobiliary scintigraphy in acute cholecystitis

Hepatobiliary scintigraphy is a mature imaging technique for evaluation of patients with acute cholecystitis (AC). It is effective in calculous and acalculous forms of AC. The test is used in contemporary medical practice as the arbiter when the findings from screening abdominal ultrasound do not fit a clinical picture. It is also performed in severely ill patients who have AC suspected on other testing, but whose frail condition and high operative risk demand the highest level of certainty. This review, therefore, examines all technique variations of hepatobiliary scintigraphy, offering an approach that may best fit a variety of clinical situations and philosophies on AC.

Early morphine administration to expedite gallbladder visualization during cholescintigraphy for acute cholecystitis

A 58-year-old woman underwent emergent hepatobiliary imaging for evaluation of possible acute calculous cholecystitis. Intravenous morphine was administered 10 minutes after small bowel activity was first seen. The gallbladder visualized promptly after morphine administration, effectively excluding cystic duct obstruction and acute cholecystitis. The entire imaging procedure was completed and a final diagnosis made within 30 minutes.

Refinement of the positive predictive value of gallbladder nonvisualization after morphine administration for acute cholecystitis based on the temporal pattern of common bile duct activity

The authors previously reported two major patterns in the time-activity curve of the common hepatic bile duct (BD) after morphine administration in patients with gallbladder nonvisualization. The first pattern consists of a gradual increase in BD activity (of variable duration) occurring during a simultaneous decrease in liver parenchymal activity (BD increase), representing the physiologic effects of morphine administration. The second pattern consists of a continuous decrease in BD activity that parallels the activity in the liver parenchyma (BD decrease), representing lower or no physiologic effects of morphine administration. The authors hypothesize that gallbladder nonvisualization associated with a continuous decrease in BD activity after morphine administration will have a lower positive predictive value (PPV) for acute cholecystitis than gallbladder nonvisualization associated with an increase in BD activity.

METHODS

Thirty-six patients who had morphine-augmented cholescintigraphy were divided into two groups: 19 with BD increase after morphine administration and 17 with BD decrease.

RESULTS

Of the 36 patients, 22 had acute cholecystitis. The positive predictive value (PPV) of gallbladder nonvisualization was 61%. All of the remaining 14 had chronic cholecystitis. Of 19 patients with BD increase, 15 had acute cholecystitis (PPV = 79%), whereas only 7 of 17 patients with BD increase (PPV = 41 %) had acute cholecystitis (P = 0.023 by the one-tailed and 0.038 by the two-tailed Fisher exact tests).

CONCLUSIONS

Gallbladder nonvisualization after morphine administration with the pattern of BD decrease is not as reliable (intermediate probability in this series) for the diagnosis of acute cholecystitis as is nonvisualization of the gallbladder in patients with a pattern of BD increase (high probability).

Variable bile retention on cholescintigraphy after morphine administration

Intravenous morphine sulfate has been used in conjunction with cholescintigraphy. We studied the variations in the degree and duration of the effects of 2 mg morphine on biliary kinetics in patients with gallbladder nonvisualization and undertook a comparison with biliary kinetics in patients not given morphine. Of 24 morphine-augmented cholescintigrams that were obtained without additional injection of technetium-99m diisopropyl-iminodiacetic acid (DISIDA), 19 showed continued gallbladder nonvisualization. Time-activity curves (TACs) of the liver parenchyma and common bile/hepatic duct (CD) of the entire study (before and after morphine) were obtained. In two patients, the CD was not sufficiently visualized to define a region of interest. In 17 patients, the peak CD activity was observed between 14 and 47 min after injection of 99mTc-DISIDA. In these 17, the TAC of the CD was declining essentially in parallel with the TAC of the liver parenchyma at the end of the first hour before morphine. After morphine injection, CD activity slowly increased for a variable duration in nine patients, while it continued to decrease in eight. CD activity between 1 h and 2 h showed a continuously decreasing pattern in another group of 20 patients who did not receive morphine despite gallbladder nonvisualization at 1 h. In summary, no significant effect of 2 mg of intravenous morphine on biliary kinetics was detected scintigraphically in a considerable proportion of patients. Also, there was considerable variation in the duration of the effect of morphine, when such an effect was present. This observation may have significant clinical implications for morphine-augmented cholescintigraphy.

Cholecystokinin and morphine pharmacological intervention during 99mTc-HIDA cholescintigraphy: a rational approach

Pharmacological intervention with either cholecystokinin-8 (CCK-8) or morphine during 99mTc- hepatoiminodiacetic acid (HIDA) cholescintigraphy is required primarily for the assessment of the diseases affecting the gallbladder, the common bile duct, or the sphincter of Oddi. For imaging, the patient should be prepared by an overnight fast, or with 4 hours of minimum fast. Pre-emptying with CCK-8 is probably undesirable and should either be avoided or one should wait for at least 4 hours after CCK-8 to begin the 99mTc-HIDA study to achieve higher specificity of the test for acute cholecystitis. When he gallbladder is not observed by 60 mins in a clinical setting of acute cholecystitis, a dose of 0.04 mg/kg of morphine is administered intravenously and imaging continued for an additional 30 mins. Nonvisualization of the gallbladder by 90 mins with morphine in an appropriate clinical setting is diagnostic for acute cholecystitis. When the gallbladder is not observed by 60 min but is seen with morphine administered after 60 mins, a positive diagnosis of abnormal gallbladder function can be made. When the gallbladder is observed in a clinical setting of biliary pain or chronic calculous or acalculous cholecystitis, CCK-8 at a dose rate of 3.3 ng/kg/min is infused intravenously for 3 mins (10 ng/kg/3 min) for the measurement of the ejection fraction. An ejection fraction value of less than 35% is indicative of calculous or acalculous chronic cholecystitis. The gallbladder emptying is directly related to the total number of cholecystokinin receptors in the smooth muscle. The ejection fraction can be controlled to any desired level simply by controlling the dose rate or the duration of infusion of CCK-8. Morphine and other opiate metabolites circulate for many hours in blood and act on the sphincter of Oddi and decrease the gallbladder ejection fraction. Careful drug history, especially that of opiates, is very critical in all subjects with a low ejection fraction before assigning an abnormality to the gallbladder motor function.

Morphine cholescintigraphy in the evaluation of hospitalized patients with suspected acute cholecystitis

OBJECTIVE

The authors determined if the diagnosis of acute cholecystitis can be accurately made or reliably eliminated by the use of morphine-augmented radionuclide cholescintigraphy (morphine cholescintigraphy [MC]) in hospitalized patients in whom the diagnosis is in doubt. SUMMARY/BACKGROUND DATA: Diagnosis of acute cholecystitis, calculous or acalculous, may be difficult in patients hospitalized for abdominal pain or other illnesses. Clinical signs often are obscure, and routine imaging studies are nonspecific or associated with a high incidence of false-positive tests. The authors report the use of MC in the evaluation of 163 hospitalized patients for acute cholecystitis over an 8-year period.

METHODS

All patients suspected to have acute cholecystitis initially had standard cholescintigraphy performed, which showed nonvisualization of the gallbladder, and then were given morphine sulfate (0.05-0.1 mg/kg, intravenously). Patients were divided into the following three groups: I--acute abdominal pain (N = 53); II--hospitalized for associated illness (N = 49); and III--critically ill (N = 61).

RESULTS

Overall, MC confirmed the diagnosis of acute cholecystitis in 75 patients (46%), including 23 cases of acalculous cholecystitis. Visualization of the gallbladder occurred within 60 minutes of intravenous administration of morphine sulfate in all patients. Cystic duct obstruction and, presumably, the diagnosis of acute cholecystitis was excluded in 79 patients, including 38 who were critically ill. There were eight false-positive and one false-negative studies. Morphine cholescintigraphy had a sensitivity of 99%, a specificity of 91%, a positive predictive value of 0.9, a negative predictive value of 0.99, and an overall accuracy of 94%.

CONCLUSIONS

In hospitalized patients with nonvisualization of the gallbladder after standard cholescintigraphy, MC is highly accurate, especially in predicting the absence of acute cholecystitis in patients with known risk factors.

Augmented cholescintigraphy: its role in detecting acute and chronic disorders of the hepatobiliary tree

Cholecystagogue cholescintigraphy can be employed as a means of (1) confirming the surgeon's and/or gastroenterologist's clinical impression of symptomatic chronic acalculous biliary disease, (2) better understanding the pathophysiology of gallbladder disease, (3) preparing patients for hepatobiliary scintigraphy who have fasted for longer than 24-48 hours and who are suspected of acute cholecystitis, and (4) reducing the time required to confirm the clinical impression of acute cholecystitis. Morphine-augmented cholescintigraphy is also used to decrease the time required to determine cystic duct patency. Phenobarbital-augmented cholescintigraphy is used as a means of increasing the accuracy of hepatobiliary scintigraphy in differentiating neonatal hepatitis from biliary atresia. Nonpharmacological interventions and augmentations have been employed to maintain the high degree of accuracy of cholescintigraphy in confirming the clinical impression of acute cholecystitis. The efficacy of these modalities in detecting acute and chronic disorders of the hepatobiliary tree as well as how and why they are performed comprise the contents of this article.