Gallbladder response to a second dose of cholecystokinin during the same imaging study.

Patients on total parenteral nutrition or after prolonged fasting may require treatment with cholecystokinin (CCK) prior to hepatobiliary imaging. Some may also require evaluation of gallbladder (GB) contractility, and the need for a second dose of CCK may arise. It is not clear whether gallbladder function can be adequately evaluated with CCK when a previous CCK dose had already been administered. We studied ten normal subjects to evaluate GB response to a second CCK injection. The subjects received 20 micrograms/kg sincalide in a 3-min infusion prior to administration of technetium-99m disofenin. They then received an identical sincalide dose at 60 min postinjection, and imaging was continued for another 30 min to quantify GB contraction. Gallbladder ejection fraction (GBEF) values ranged from 42-98% (mean: 71.5 +/- 19%). Pretreatment with CCK does not preclude GB contraction evaluation with a second dose of CCK. Expected GBEF values are similar to those obtained with single CCK injections.     

The various scintigraphic patterns of Warthin's tumor

The authors' experience with salivary gland imaging in patients with Warthin's tumor was reviewed and the scans correlated with the pathologic findings of each tumor in an attempt to explain the scintigraphic variants found. Most Warthin's tumors show increased perfusion on imaging. The predischarge static images have a low sensitivity, detecting only 33% of the tumors. Warthin's tumors may appear hot, warm, or cold on the predischarge images but invariably become hot in the postdischarge study, for a 100% sensitivity. Many tumors reveal internal warm or cold areas. These focal defects correlate well with the presence of intratumoral cysts. The presence of these mixed lesions should not lead the physician away from the diagnosis of Warthin's tumor.     

Pancreatic phlegmon

The clinical course of 19 patients with pancreatic phlegmon, as diagnosed by computed tomography (CT) and clinical criteria, was assessed retrospectively and compared to that of eight patients with pancreatic abscess diagnosed either at surgery or with percutaneous aspiration. Controls consisted of 55 patients with uncomplicated acute pancreatitis without CT scans and 11 patients with acute pancreatitis in whom CT scans were negative or only consistent with acute pancreatitis (no phlegmon). The age, sex, and presumed etiology of the pancreatitis were not significantly different in the four groups. Patients with phlegmon had a higher incidence of severe pancreatitis as defined by Ranson's criteria, presence of an abdominal mass, as well as a longer duration of fever, abdominal pain and leukocytosis than controls without CT scans. With the exception of a palpable abdominal mass and fever lasting over five days, the results were similar when comparing the phlegmon group and controls with CT scans, although the severity of the disease and prolonged abdominal pain tended to be increased in the former patients. There was no statistically significant difference in clinical or laboratory criteria between the phlegmon and abscess groups, although the latter group had longer hospital stays and periods with no oral intake (npo). Management of patients with phlegmon tended to include TPN, longer npo periods, antibiotics, and longer hospital stay than in controls without CT scans. Controls with CT scans were managed similarly to the phlegmon group because of prolonged amylase elevation and abdominal pain, Percutaneous aspiration was successful in differentiating abscess from phlegmon in five of six cases. Major complications were rare in the phlegmon group and spontaneous resolution was the rule. Pancreatic phlegmon is a distinct clinical/radiologic entity which may be very difficult to differentiate clinically from pancreatic abscess. Early percutaneous thin-needle aspiration of the inflammatory mass (under CT guidance) seems to be the diagnostic procedure of choice. Management is nonsurgical unless complications arise. The role of TPN and antibiotics is unknown, and controlled studies of these therapeutic approaches in pancreatic phlegmon are needed.     

Gallbladder response to a second dose of cholecystokinin during the same imaging study

Patients on total parenteral nutrition or after prolonged fasting may require treatment with cholecystokinin (CCK) prior to hepatobiliary imaging. Some may also require evaluation of gallbladder (GB) contractility, and the need for a second dose of CCK may arise. It is not clear whether gallbladder function can be adequately evaluated with CCK when a previous CCK dose had already been administered. We studied ten normal subjects to evaluate GB response to a second CCK injection. The subjects received 20 g/kg sincalide in a 3-min infusion prior to administration of technetium-99m disofenin. They then received an identical sincalide dose at 60 min postinjection, and imaging was continued for another 30 min to quantify GB contraction. Gallbladder ejection fraction (GBEF) values ranged from 42–98% (mean: 71.5±19%). Pretreatment with CCK does not preclude GB contraction evaluation with a second dose of CCK. Expected GBEF values are similar to those obtained with single CCK injections.     

Ionic iodinated contrast medium and amobarbital sodium mixtures: potential for precipitation.

When a small amount of diatrizoate meglumine, an ionic iodinated contrast medium, is left in a catheter system before injection of amobarbital sodium or when the contrast medium is intentionally mixed with amobarbital sodium, a potentially dangerous situation occurs. The authors showed in vitro that a dense precipitate forms in this situation. This is due to an acid-base reaction between the relatively acidic contrast medium and basic barbiturate and the subsequent formation of insoluble amobarbital.     

The influence of biological and technical factors on the variability of global and regional brain metabolism of 2-[18F]fluoro-2-deoxy-D-glucose.

This study investigated the influence of biological and technical factors on variations of global and regional cerebral metabolic rate of glucose (CMRglc) measured with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG). Twelve male volunteers (22-40 years) were investigated on three or four occasions for a total of 42 studies. We calculated the variance/covariance of the following parameters: CMRglc, six parameters of the blood clearance of [18F]FDG, hour of injection, peak time of blood radioactivity, and six components of the operational equation (nonradioactive blood glucose concentration, brain radioactivity, two integrals, numerator, and denominator). There was correlation among these six components, except for nonradioactive blood glucose. However, the correlation between the CMRglc and the individual components of the operational equation was poor. The inter- and intrapersonal CMRglc coefficients of variations were 13.8 and 7.1%, respectively. In contrast, coefficients of variations of the numerator and denominator of the operational equation were 34.6 and 32.6%, respectively, and were always in the same direction. No correlation was found between CMRglc and the technical factors in the numerator and denominator of the operational equation. Factor analysis disclosed that a single factor was responsible for 70% of the variance. This factor included caudate, putamen, thalamus, frontal cortex, temporal cortex, and cingulate gyrus. These structures are involved with multiple complex functions, from autonomic motor control to behavior and emotions. The intrinsic metabolic variability of these structures, along with the basal metabolic processes that are continuously going on in the brain, may be the best explanation for the variance encountered in our investigation.