Subacute thyroiditis and dyserythropoesis after influenza vaccination suggesting immune dysregulation

Subacute thyroiditis (SAT) is an extremely rare complication of influenza vaccination. Several infectious agents have been related with SAT. It is also well known the association between HLA-B35 and the development of SAT. We describe a case of subacute thyroiditis and dyserythropoesis occurring shortly after administration of an influenza vaccine in a 55-year-old man with history of diabetes and psoriasis, family history of autoimmunity without clinical evidence of acute viral infection prior to the onset of symptoms. We propose that, the events occurring in the patient may be explained as result of complex interactions between the individual genetic background and environmental exposure to infectious agents that generated a pro-inflammatory status, where the vaccine was the trigger for the subsequent alterations in thyroid and bone marrow. These findings highlight the importance of immunogenetic factors involved in response to vaccination that is the central theme in the growing field of 'vaccinomics'.

Hyperthyroidism, hyperfunctioning thyroid nodule, and thyroid cancer in a young female: a rare and unusual coexistence

The prevalence of concomitant thyroid carcinoma with Grave's disease has been reported to range from 0 to 10%. Many controversies exist in the literature regarding the diagnostic workup and management in these types of patients. We are reporting a case of a 31 year old woman who had Graves' disease, a palpable thyroid nodule, and results from a thyroid scan revealed a "hot" nodule. Interestingly, an ultrasound guided FNA of the "hot" nodule showed papillary thyroid microcarcinoma. Finally, a total thyroidectomy showed multilobar tumor involvement. The diagnostic tools employed to establish the proper management strategy for this patient were based on data in the literature that is full of discrepancies. The fact that Grave's disease occurs concomitantly with thyroid cancer, specifically the papillary type, is an indisputably rare combination. One rare feature on our clinical case was the reported malignancy of a papillary carcinoma within a "hot" nodule which usually is much less that 1%. Many studies describe an increasing incidence of Grave's disease patients with concomitant papillary thyroid carcinoma. One possible explanation for these findings could be improvements in medical technology of screening tools. We propose that, thyroid ultrasonography should be integrated in the diagnostic workup in patients presenting with Graves' disease, especially in those presenting with palpable nodules. Fine needle biopsy should not be restricted to cold nodules.

Progesterone alters biliary flow dynamics

OBJECTIVE

To test the hypothesis that progesterone alters sphincter of Oddi and gallbladder function and, therefore, bile flow dynamics.

SUMMARY BACKGROUND DATA

Although the effects of progesterone on the biliary tract have been implicated in the increased incidence of gallstones among women, the specific effects of prolonged elevation of progesterone levels, such as occurs with contraceptive progesterone implants and during pregnancy, on the sphincter of Oddi and biliary flow dynamics are still incompletely understood.

METHODS

Adult female prairie dogs were randomly assigned to receive subcutaneous implants containing either progesterone or inactive pellet matrix only. Hepatic bile partitioning and gallbladder emptying were determined 14 days later using 99mTc-Mebrofenin cholescintigraphy.

RESULTS

Significantly less hepatic bile partitioned into the gallbladder in progesterone-treated than in control animals. The gallbladder ejection fraction was significantly reduced from 73+/-6% in controls to 59+/-3% in the progesterone-treated animals. The rate of gallbladder emptying was significantly reduced from 3.6+/-0.3%/minute to 2.9+/-0.1%/minute.

CONCLUSIONS

Progesterone administered as subcutaneous implants alters partitioning of hepatic bile between gallbladder and small intestine and, therefore, gallbladder filling. Progesterone also significantly impairs gallbladder emptying in response to cholecystokinin. The effects of progesterone on the sphincter of Oddi and the gallbladder may contribute to the greater prevalence of gallstones and biliary motility disorders among women.

Gender influences sphincter of Oddi response to cholecystokinin in the prairie dog

Although gallstones and disorders of biliary tract motility are both more common in women than men, sphincter of Oddi motility has not previously been compared between the sexes. In this study, cholescintigraphy (under ketamine and diazepam anesthesia) was used to determine gallbladder emptying rate and ejection fraction in response to cholecystokinin (CCK) in eight male and six female prairie dogs fed a nonlithogenic diet. Ten days later, under alpha-chloralose anesthesia, sphincter of Oddi phasic wave activity was monitored for 10-min intervals before (control), during 20 min of CCK infusion, and for 20 min after infusion. Gallbladder emptying rate and ejection fraction and baseline sphincter of Oddi frequency, amplitude, and motility index (= frequency x amplitude) did not differ significantly between the sexes. Sphincter of Oddi phasic wave frequency was increased during CCK infusion in both males and females, but the change in amplitude was significantly greater in females, than males. We conclude that the increased incidence of biliary tract disease in women may be due to altered sphincter of Oddi hormonal response.

Intrasphincteric botulinum toxin for the treatment of achalasia

BACKGROUND

Achalasia is a disorder of swallowing in which the lower esophageal sphincter fails to relax. We report the use of botulinum toxin, a paralytic agent, for the treatment of this condition.

METHODS

In a double-blind trial, 21 patients with achalasia received either 80 units of botulinum toxin or placebo, injected endoscopically into the lower esophageal sphincter. One week later, the response to treatment was assessed on the basis of changes in the symptom scores (measured on a scale from 0 to 9), pharyngoesophagograms, and results of esophageal manometric and scintigraphic studies. Patients who received placebo initially were subsequently treated with botulinum toxin. After six months, esophageal scintigraphy was repeated.

RESULTS

One week after treatment, the mean decrease in the symptom score was 5.4 points for the patients treated with botulinum toxin and 0.5 point for the placebo group (P = 0.001). The mean decrease in the pressure of the lower esophageal sphincter was 33 percent in the treatment group, as compared with a mean increase of 12 percent in the placebo group (P = 0.02), and the mean increase in the width of the opening of the lower esophageal sphincter was 204 percent in the treatment group, as compared with a mean decrease of 14 percent in the placebo group (P = 0.02). Nineteen of the 21 patients treated with botulinum toxin had symptomatic improvement initially; after six months 14 patients were still in remission. This improvement was accompanied by a decrease in esophageal retention that was sustained at six months (46 percent, as compared with a pretreatment value of 77 percent; P = 0.04). There were no serious adverse effects.

CONCLUSIONS

Injection of botulinum toxin into the lower esophageal sphincter is an effective, safe, and simple method of treatment for achalasia, with results that are sustained for several months.

Differing scintigraphic patterns of lumboperitoneal shunt dysfunction in patients with normal pressure hydrocephalus and pseudotumor cerebri

The scintigraphic patterns of dysfunctioning lumboperitoneal shunts (LPS) may vary with the underlying disease. The authors reviewed 22 LPS studies performed on 15 patients during the past 2 years and correlated the findings with the patency status of the shunt as determined by brain CT/MRI and surgical revision. Most of the patients also had cerebrospinal fluid (CSF) pressure monitoring. Fifteen studies were performed in patients with LPS for the treatment of normal pressure hydrocephalus (NPH) and 7 were performed in patients with LPS for pseudotumor cerebri (PTC). After intrathecal administration of 0.5-1 mCi of In-111 DTPA, sequential 1 minute images of the abdomen were obtained for 20 minutes. Static images of the abdomen were then obtained at 30 minutes and 1, 2, 4, and 24 hours with imaging of the head at 4 and 24 hours. All NPH patients with partial obstruction had tracer activity in the peritoneal cavity with little or no shunt tubing visualization. However, all had marked penetration of the tracer into the lateral ventricles. Pseudotumor cerebri patients with partial obstruction also showed tracer entry into the peritoneal cavity. Shunt tubing and tracer extravasation into the needle tract, at the site of lumbar puncture was seen only in patients of PTC, probably because of high intracranial pressure. Although the tracer flowed quickly into the basal cistern in all patients with PTC, it entered the lateral ventricles. Complete shunt obstruction was characterized by nonvisualization of activity in the peritoneal cavity and flow of the tracer into the basal cistern within 1 hour after injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Gallbladder ejection fraction. Nondiagnostic for sphincter of Oddi dysfunction in patients with intact gallbladders

Thirty consecutive patients with intact gallbladders and biliary pain were evaluated to determine whether gallbladder ejection fraction could identify sphincter of Oddi dysfunction. The mean gallbladder ejection fraction was 45% in patients with abdominal pain and 72% in normal controls. Gallbladder ejection fractions were then correlated with endoscopically measured sphincter of Oddi pressures in patients with abdominal pain. The mean gallbladder ejection fraction was 41% in 7 patients with elevated sphincter pressures and 46% in 23 patients with normal pressures (P = NS). Thirty-six percent of patients with elevated pressures and 33% of patients with normal pressures had abnormal gallbladder ejection fractions. Gallbladder ejection fraction had a sensitivity of 33%, a specificity of 63%, and a positive predictive value of 25% for detection of elevated pressures. Regression analysis revealed a poor correlation between sphincter pressure and gallbladder ejection fraction (r2 = 0.02). These findings suggest that gallbladder ejection fraction cannot be used to diagnose sphincter of Oddi dysfunction in patients before they undergo cholecystectomy.

Brain SPECT in a case of cortical blindness

BACKGROUND

Published reports on patients with cortical blindness describe bilateral brain hemispheric lesions visualized in radiological and functional imaging studies.

CASE DESCRIPTION

We present a case with a unilateral lesion on radiological studies and bilateral abnormalities on single-photon emission-computed tomographic (SPECT) scanning.

CONCLUSIONS

SPECT images correlated much more closely than radiological studies with the patient's clinical status. We suggest that SPECT scanning can be a useful indicator of focal brain dysfunction in brain injury in spite of normal radiological studies. We also hypothesize that our patient's clinical and functional imaging findings could be attributed in part to the process of diaschisis.

Signs of cerebral atrophy on single-photon emission tomography

Cerebral atrophy often coexists with other brain disorders and by itself may alter the pattern of cerebral perfusion. If unrecognized, it may confound diagnoses based on brain single-photon emission tomography (SPET). In this retrospective study, we describe and evaluate criteria for the diagnosis of cerebral atrophy on technetium-99m hexamethylpropylene amine oxime brain SPET studies. The SPET scans of 11 patients with cerebral atrophy and ten controls were evaluated for the presence of a prominent interhemispheric fissure, presence of prominent cerebral sulci, separation of thalamic nuclei, and pronounced separation of caudate nuclei. The SPET studies were interpreted by two independent observers blind to the findings of magnetic resonance imaging, which provided the final diagnosis of cerebral atrophy. The combination of the four scintigraphic signs was accurate in the diagnosis of cerebral atrophy in 95% of the cases and had a sensitivity of 91% and a specificity of 100%.

Clinical utility of posttreatment radioiodine scans in the management of patients with thyroid carcinoma

A retrospective comparison was performed of whole body scans obtained before and after 143 131I treatments in 93 patients with thyroid carcinoma. Pretreatment scans were performed with 74-185 megabecquerel 131I, and posttreatment scans were performed 5-12 days after dosing with 1.1-7.4 GBq. In 38 (27%) treatment cycles, the results of posttreatment and pretreatment scans differed. Only 14 (10%) posttreatment scans detected new locations of metastatic disease. Seventeen posttreatment scans demonstrated metastatic locations that were already known from previous studies but not seen on the pretreatment scan. Among parameters evaluated (including demographic and histological characteristics), only the combination of age at diagnosis less than 45 yr and history of previous 131I therapy contributed to the likelihood of a new finding on posttreatment scan (relative risk, 3.8). Five of the 14 new posttreatment scan findings were subsequently corroborated by other radiographic studies or thyroglobulin elevations, all in patients with extrathyroidal extension of the primary tumor. Seven (5%) posttreatment scans were unable to detect a focus of uptake seen on the corresponding pretreatment scan. In conclusion, posttreatment scans were most likely to reveal clinically important new information in young patients who had previously received 131I therapy. In older patients and those without previous 131I therapy, posttreatment scans rarely yielded new information that would potentially alter the patient's prognosis.

Kidney-to-liver ratio. A simple scintigraphic parameter for routine individual renal function assessment in children

DTPA renography is commonly used for measuring relative renal function. However, in patients with bilateral renal disease or solitary kidneys, split function studies are of no value. Available techniques to quantify individual renal function are either time consuming or inaccurate. The authors validate the kidney-to-liver ratio at 3 minutes (K3/L3) as an index of renal function, showing excellent correlation with GFR. Normal K3/L3 ranges were then computed in 113 pediatric kidneys (age 2 days to 16 years) and 24 adults. Indicative of renal maturation, the K3/L3 rapidly rose from a value of 1.32 at birth to 2.02 at 6 months. Subsequently, it increased slowly to reach a peak of 2.34 at age 2, followed by gradual decline to adult values after age 5. This decrease is due likely to continued growth of the hepatic blood pool after renal maturation. GFR followed the same maturation pattern to reach a plateau around 2 years of age. K3/L3 reflects individual kidney function, and it requires no blood sampling or urine collection. By establishing normal values at different stages of maturity, this method provides identification and quantification of renal dysfunction in infants, children, and adults.

Noncompartmental and compartmental modeling of the kinetics of carbon-11 labeled pyrilamine in the human brain

The kinetic pattern of a 11C-labeled histamine H1 receptor antagonist, [11C]pyrilamine, was investigated in the human brain by factor analysis of dynamic PET studies. Tissue time activity curves were also processed by compartment model curve fitting preceded by deconvolution analysis. Factor analysis revealed two statistically significant and physiologically meaningful kinetic patterns: one for specific and another for nonspecific binding of the radioligand. From these two factors a compartment model containing two tissue compartments (one for specific binding and another for nonspecific binding and free ligand) was constructed. The two-compartment model was also supported by the impulse response function, which was obtained by deconvolution and showed two components. The factor image constructed from factor two demonstrated a distribution pattern characteristic for brain regions rich (frontal, parietal, and temporal lobes) or poor (occipital lobe and cerebellum) in H1 receptors. Blockade of H1 receptors with unlabeled pyrilamine, diphenhydramine, or hydroxyzine caused a significant reduction of this factor. Blockade produced no significant changes in factor one representing nonspecific binding. We conclude that the kinetics of [11C]pyrilamine in the brain can be described by two tissue compartments, one related to the distribution of the H1 receptors. Factor analysis of dynamic studies can be used to locally separate these two compartments, for identification of regions rich and poor in H1 receptors and for noninvasive quantitative investigation of the effects of H1 receptor blockers such as pyrilamine, diphenhydramine, or hydroxyzine.

Preoperative localization of occult medullary carcinoma of the thyroid gland with single-photon emission tomography dimercaptosuccinic acid

BACKGROUND

Patients who undergo thyroidectomy for medullary carcinoma of the thyroid gland (MTC) often have elevations of postoperative serum calcitonin levels, which are indicative of metastatic or residual disease. It has been extremely difficult to localize tumor in these patients with standard diagnostic studies such as ultrasonography, computed tomography, or magnetic resonance imaging scans. Previous studies have suggested that planar technetium 99m (V) dimercaptosuccinic acid (DMSA) scintigraphic scans can localize MTC in these patients. We have recently increased the sensitivity of planar scintigraphic images by using single-photon emission tomography (SPECT). This study was performed to compare the sensitivity of planar DMSA scans with that of SPECT DMSA scans.

METHODS

Two normal volunteers and three patients with occult MTC after previous total thyroidectomy underwent planar and SPECT DMSA scans. Each patient subsequently underwent surgical exploration based on the DMSA scans.

RESULTS

Physiologic DMSA uptake was noted in the nasopharynx, axial skeleton, breast, liver, spleen, heart, kidneys, urinary bladder, great vessels, and skeletal muscles in both normal volunteers and patients with occult MTC. Planar DMSA scans and dynamic computed tomographic scans failed to localize MTC in any of these patients who had minimal disease. SPECT DMSA scans correctly localized cervical MTC in two of three patients, as proved by subsequent surgical resection. One patient who had a negative cervical exploration is presumed to have had a false-positive SPECT DMSA scan.

CONCLUSIONS

SPECT DMSA scans appear to be a sensitive, safe, and noninvasive localization technique for patients with occult MTC who have undergone previous thyroidectomy.

Lag phase in solid gastric emptying: comparison of quantification by physiological and mathematical definitions

Lag phase is considered an important parameter of solid gastric emptying studies. However, different methodologies with their own normal values and physiologic implications are advocated for lag phase measurements. We applied both physiologic and mathematic approaches to quantify lag phases from identical image data sets for direct comparison of these two approaches. Gastric emptying studies were performed on 22 patients using a standard solid meal to calculate the lag phase in each using three different methods: (1) visual analysis to determine time when activity first appeared in the duodenum (LagPh); (2) time-activity curves to determine time of 2% decrease from peak stomach activity (LagCu); and (3) a mathematical definition using the modified power exponential method (TLAG). In addition, time of peak antral activity (AntPk) was calculated. The values for LagPh and LagCu were very similar (mean: 14.6 versus 15.2 min) and correlated well with each other (r = 0.89). TLAG using the power exponential showed different values (mean: 34.7 min) and correlated well only with AntPk (mean: 35.1 min; r = 0.92). We conclude that LagPh and LagCu estimate the time of onset of gastric emptying; the time when the smaller particles in the meal (< 1-2 mm) begin to leave the stomach (onset of variable emptying phase). On the other hand, TLAG and AntPk estimate total trituration time (time for most of meal to be processed) and signal the beginning of the constant gastric emptying phase.

Erythromycin accelerates gastric emptying after pancreaticoduodenectomy. A prospective, randomized, placebo-controlled trial

OBJECTIVE

This study tested the hypothesis that erythromycin, a motilin agonist, reduces the incidence of early DGE after pancreaticoduodenectomy.

SUMMARY BACKGROUND DATA

Delayed gastric emptying (DGE) is a leading cause of morbidity after pancreaticoduodenectomy, occurring in up to 40% of patients. The pathogenesis of DGE has been speculated to involve factors such as peritonitis from anastomotic leaks, ischemia to the antropyloric muscles, and gastric atony in response to resection of the duodenal pacemaker or reduction in circulating motilin levels.

METHODS

Between November 1990 and January 1993, 118 patients undergoing pancreaticoduodenectomy completed this prospective, randomized, placebo-controlled trial. The patients received either 200 mg of intravenous erythromycin lactobionate every 6 hours (n = 58), or an identical volume of 0.9% saline (n = 60) from the third to tenth postoperative days. On the tenth postoperative day, a dual phase radionuclide gastric emptying study was performed.

RESULTS

The erythromycin and control groups were comparable regarding multiple preoperative, intraoperative, and postoperative factors. The erythromycin group had a 37% reduction in the incidence of DGE (19% vs. 30%), a significantly reduced (p < 0.05) need to reinsert a nasogastric tube for DGE (6 vs. 15 patients), and a significantly reduced (p < 0.01) per cent retention of liquids at 30 minutes and solids at 30, 60, 90, and 120 minutes. No major adverse reactions to erythromycin were observed.

CONCLUSIONS

Erythromycin is a safe, inexpensive drug that significantly accelerates gastric emptying after pancreaticoduodenectomy and reduces the incidence of DGE by 37%. These data support the use of erythromycin to decrease early DGE after pancreaticoduodenectomy.

Comparison of left anterior oblique, anterior, and geometric mean methods in gastric emptying assessment of postpancreaticoduodenectomy patients

Although left anterior oblique (LAO) gastric emptying studies appear to be an adequate alternative to geometric mean (GM) measurements in patients with normal gastric anatomy, it is not clear whether they can be used after gastric or duodenal surgery. In this study, dual-phase gastric emptying studies with combined solid-liquid meal were performed in 54 patients who had undergone pancreaticoduodenectomy (Whipple procedure). Gastric emptying was studied with GM, LAO, and anterior (ANT) methods. T1/2 and percent gastric retention at 10, 30, 60, 90, and 120 minutes were calculated. Results from the three methods were compared using correlation analysis and the t test. The t test showed no significant difference in T1/2 and percent retention values between the GM and LAO or ANT views. The solid emptying T1/2 showed a better correlation between GM and LAO values (r = 0.824) than between GM and ANT (r = 0.589). For the liquid T1/2, the reverse was true. Correlation between GM and ANT (r = 0.939) was better than between GM and LAO (r = 0.839); however, both LAO and ANT views correlated well with GM liquid emptying. It is concluded that the LAO view can replace GM gastric emptying methods in postpancreaticoduodenectomy patients for evaluation of both solid and liquid emptying, although the ANT view appears completely adequate for the study of liquid emptying.

Normalized clearance-to-uptake slope ratio: a method to minimize false-positive diuretic renograms

The success of diuretic renography in the evaluation of children with renal outflow tract obstruction has been hampered by a high incidence of false-positive and indeterminate results. The main causes of interpretative errors are collecting system dilatation and impaired renal function. In this prospective study, we introduce a parameter with the potential to overcome these two problems: the normalized slope ratio (SRn). This ratio is calculated from the division of the maximum renal clearance slope by the maximum renal uptake slope, both normalized to peak renal activity. Fifty-one children (94 renal units) were evaluated. Traditional parameters such as diuretic half-time and percentage of retention at 30 min showed specificities of 77% and 85%, respectively. However, the normalized clearance slope increased specificity to 94% and SRn further improved it to 98%. The SRn takes into account the renal uptake curve, whose slope is dependent on glomerular function, and thus may correct for renal dysfunction. It also differentiates obstructed from patent kidneys even in cases with significant collecting system dilatation. As shown by regression analysis, it is independent of collecting system size. We recommend the routine use of this parameter to reduce false-positive and indeterminate results of diuretic renograms.

Estimating renal function from the visual analysis of Tc-99m DTPA images

Eleven visual parameters of Tc-99m DTPA imaging studies were evaluated to identify scintigraphic findings that best detect changes in renal function, to determine at which GFR levels they appear, and to establish criteria for visual estimation of renal function. Visual parameters were compared to in vitro GFR determinations in 41 patients. Three visual parameters offered best discrimination. The first one appeared at GFR values below 70 mL/min (sensitivity: 76%). The renal peak activity on the flow study (normally equal or greater than aortic) no longer reached the intensity of the aortic peak (pK < pA). The second parameter appeared at GFR values below 50 mL/min (sensitivity: 85%). The estimated kidney-to-liver ratio in the 2-minute image (usually 3 or greater) decreased to values less than 3. The third scintigraphic finding, pelvicalyceal system nonvisualization, appeared at GFR levels below 20 mL/min (sensitivity 100%). Use of these 3 scintigraphic findings allows categorization of patients into four functional groups: 1) severe dysfunction (GFR: 0-20 mL/min), 2) moderate to severe dysfunction (GFR: 21-50 mL/min), 3) moderate dysfunction (GFR: 50-70 mL/min), and 4) Normal study (GFR > 70 mL/min). Visual analysis of Tc-99m DTPA images does not identify patients with mildly decreased renal function (GFR: 70-90 mL/min).

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.

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.

Factor analysis of regional cerebral glucose metabolic rates in healthy men

Cerebral glucose utilization measured with fluorine-18-fluoro-2-deoxy-D-glucose is characterized by considerable variability both among different persons and for the same person examined on different occasions. The goal of this study was to explore whether some regions of the brain were more variable than others with respect to glucose utilization and whether there was a pattern in their covariance. The global and regional cerebral utilization of glucose was measured in 12 healthy young volunteers on 3 or 4 occasions. In all, 24 regions were examined. The interrelation of the glucose utilization rates of the brain regions was investigated by factor analysis of the metabolic rates. Some 70% of the total variance was attributable to only 1 factor, while 80% of the total variance could be attributed to 2 factors. Regions making up the first factor were the frontal and temporal cortex, cingulate gyrus, caudate nucleus, thalamus and putamen. These regions are functionally related to the limbic system. Regions of the second factor were the parietal cortex, occipital cortex and cerebellum, regions more clearly related to sensory and motor functions. The 2-factor pattern was highly reproducible, being found with different algorithms for factor extraction and rotation. Under resting conditions, the variance of cerebral metabolism seems to be primarily related to regions which are closely involved with the limbic system. Cortical regions involved primarily in motor and sensory functions have less influence on the variance.

Biliary tract complications following laparoscopic cholecystectomy: imaging and intervention

Radiologic studies and interventional procedures were performed in a series of 13 patients with biliary complications following laparoscopic cholecystectomy, and the results were evaluated. Two categories of ductal complication--minor and major--were found. Minor complications (n = 6) included bile leaks and bilomas; these were managed with percutaneous techniques or simple surgical repair. Major complications (n = 8), consisting primarily of common hepatic duct injuries or strictures, were markedly resistant to percutaneous therapy, requiring major surgical repair (hepaticojejunostomy). Percutaneous treatment of recurrent strictures after primary repair was undertaken in three patients. Diagnostically, radionuclide imaging appeared most helpful in screening for biliary complications of laparoscopic cholecystectomy, supplemented by endoscopic retrograde cholangiopancreatography and/or percutaneous transhepatic cholangiography for definitive diagnosis.

A noninvasive test of sphincter of Oddi dysfunction in postcholecystectomy patients: the scintigraphic score

The ideal noninvasive test of sphincter of Oddi dysfunction (SOD) does not exist and the diagnosis of patients with postcholecystectomy pain often relies on invasive procedures. In this paper we describe a scintigraphic test for SOD: the scintigraphic score. This score combines quantitative and visual criteria for interpretation of hepatobiliary scans. Twenty-six consecutive postcholecystectomy patients underwent hepatobiliary imaging, ERCP, and sphincter manometry. Twelve patients had SOD and 14 had normal sphincters determined by clinical findings, ERCP, and manometric studies. All patients with normal sphincter had scores of 0-4, while patients with SOD had values of 5-12 for a perfect sensitivity and specificity of 100%. Hepatobiliary scans scored in this fashion may become the noninvasive test of choice to screen postcholecystectomy patients with suspected SOD.

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.

Failure of perchlorate to inhibit Tc-99m isonitrile binding by the thyroid during myocardial perfusion studies

The thyroid gland receives an average radiation dose of 3 rads during two Tc-99m isonitrile (MIBI) myocardial perfusion studies, if 20 mCi is administered both at rest and at peak exercise. In patients with coronary artery disease, multiple myocardial perfusion studies may be required, resulting in a high level of thyroid radiation. We attempted to reduce this radiation exposure by blocking thyroidal Tc-99m MIBI uptake with oral potassium perchlorate (KCIO4). Fourteen normal subjects received 0.6g to 0.8g KCIO4 20-25 minutes before tracer injection. Subjects who received KCIO4 at rest (n = 11) did not receive KCIO4 at their stress study, and vice versa (n = 3). Thyroid uptake values were obtained with a thyroid probe 20 minutes after injection for both rest and stress studies and were corrected for saturation effects. There was no difference between fractional thyroid uptake values with and without preceding perchlorate administration: 1.9 +/- 0.5% and 1.8 +/- 0.3% (mean +/- SD), respectively. Failure to block Tc-99m MIBI uptake after intravenous (IV) injection is probably due to high thyroidal blood flow and nonspecific tracer accumulation. The concentration of this radioisotope in adjacent muscles also contributes to the high thyroid radiation dose. In summary, administration of KCIO4 before Tc-99m MIBI studies does not reduce the thyroidal radiation dose or uptake of this tracer, suggesting that thyroidal uptake of this tracer is not mediated by the iodine trapping mechanism.

Global and regional cerebral metabolic rate of 2-[18F]fluoro-2-deoxy-D-glucose in the presence of ofloxacin, a gamma-aminobutyric acid a receptor antagonist

We investigated the effects of ofloxacin, a new antibacterial quinolone gamma-aminobutyric acid A receptor antagonist, on the global and regional cerebral metabolic rates of glucose (cMRgl). Twelve healthy normal male volunteers (mean age, 26.7 years) were studied in a double-blind, placebo-controlled protocol of 11 days' duration. Results of a total of 42 positron emission tomography studies were obtained for these subjects: 12 base line, 18 during placebo, and 12 during ofloxacin administration. The conditions under which repeat positron emission tomography studies of the same subject were performed were reproduced as closely as possible. cMRgl was measured in 24 brain regions. The global cMRgl for base line, placebo, and ofloxacin were 8.82 +/- 1.17, 8.24 +/- 1.17, and 8.79 +/- 1.18 mg/min/100 g, respectively (mean +/- 1 standard deviation). The mean global differences between base line and placebo and between ofloxacin and placebo were 5.1 and 6.6%, respectively. Analysis of variance of both the global and the regional cMRgl showed no statistical difference between base-line, placebo, and ofloxacin studies. Variations in cMRgl found in this study were not related to the presence of ofloxacin. Results of our study demonstrate that ofloxacin does not increase or decrease cMRgl beyond the limits of variability of the study.

Sonographic diagnosis and grading of Hashimoto's thyroiditis

There is no ideal test for the diagnosis of Hashimoto's thyroiditis (HT). The purpose of this study was to determine the type of information sonography provides in these patients. In 47 cases of HT we identified four distinct sonographic patterns which correlated with degree of disease severity. The higher patterns had larger glands, higher antithyroid antibody titers, lower T4 and higher TSH levels, and higher incidence of hypothyroidism. With sonography we were able to suspect the diagnosis in patients with goiter of unknown etiology, to measure gland size, identify patients with functional impairment, and predict which patients required treatment. No other single test provides so much information in patients with HT.

Bowel visualization during indium-111-labelled diethylene triamine penta-acetic acid cisternography due to massive cerebrospinal fluid leak. Case report and review of the literature

We report a case of massive cerebrospinal fluid (CSF) leakage where the tracer injected intra-thecally for radionuclide cisternography was later visualized in the bowel as well as the nasopharynx. We discuss the potential implications of this finding in patients with CSF leaks. A brief review of the diagnosis of CSF leaks is included.

Gallium imaging of esophageal carcinoma: increased sensitivity with lateral views of the thorax

Ga-67 imaging has not been very successful in the detection of esophageal carcinoma. In most reports, sensitivity for the primary tumor ranged from 25-61%, but imaging had been done only in anterior and posterior (A-P) projections. We performed gallium scans in 30 patients with esophageal carcinoma, adding lateral views to the routine A-P projections, to study the effect of lateral views on tumor detection. The A-P views detected only 57% of the tumors while the right lateral visualized 89%, and the left lateral detected 100%. Some lesions may be hidden by the sternum and the spine in the routine A-P views. Previous disappointments with Ga-67 imaging of esophageal carcinoma were probably due to this technical factor. Being gallium-avid, esophageal tumors deserve further studies with this agent to determine the role of Ga-67 imaging in this condition. These studies should be performed with multiple views of the thorax or, better yet, with SPECT imaging of the chest, to circumvent the problem of sternum and spine interference.

Dual-tracer scintigraphy and subtraction studies in the diagnosis of hepatocellular carcinoma

Dual tracer scintigraphy (DTS) (technetium 99m [99mTc] sulfur colloid and gallium 67 citrate [67 gallium citrate]) of the liver and computer subtraction studies (SS) were performed in 26 patients subsequently proven to have hepatocellular carcinoma (HCC) and 32 patients with cirrhosis and focal defects on the colloid scan, with no evidence for HCC after a complete evaluation and a 2-year follow-up period. Both DTS and SS had a sensitivity of 96% and a specificity of 90.6% for HCC. There were three false positive cases (9.4%), two of which were occult abscesses. The predictive value of a positive test was 89% and that of a negative test was 97%. The smallest tumor detected measured 2 cm in diameter and was only visualized with the SS. In the clinical setting, when HCC is suspected (a situation in which tumors are usually larger than 2 cm and the pretest probability of disease is between 20% and 60%) the DTS and SS is an excellent test for the diagnosis or exclusion of HCC. It does not appear to have a role in screening programs.

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.

Liver scintigraphy in chronic hepatosplenic schistosomiasis. A predictor of disease severity

Liver-spleen scintigrams were performed in 42 patients with chronic hepatosplenic schistosomiasis. The scan patterns found are described and classified in five stages of increasing hepatic involvement. The scintigraphic classification correlates well with clinical parameters of disease severity. With higher stages, the number of symptoms and the severity of complications increase. The liver-spleen scan provides a simple and accurate means to determine extent of hepatic involvement and probabilities of complications in this disease.

A visual index of thyroid function

A visual index of thyroid uptake (VITU) is introduced as a qualitative measure of thyroid trapping. This index is determined from the 20-minute 99mTc-pertechnetate scan by visually comparing the relative tracer uptake between the thyroid and salivary glands. Three categories are defined: low, normal and elevated. The VITU correctly identified the functional status of the thyroid in 94% of 123 patients studied and agreed with the 24-hour radioiodine uptake (RAIU) in 89%. The VITU is a very simple but highly accurate, reliable and reproducible test. It was primarily designed to complement other tests of thyroid function by contributing qualitative information about the thyroidal trapping mechanism, but it can also be useful in confirming blood tests of thyroid function in cases in which one would prefer to avoid 131I administration for RAIU studies.

Thyroid scintigraphy: pinhole images versus rectilinear scans

99mTc-pertechnetate thyroid scintigraphy was performed on 67 patients with a pinhole camera and a rectilinear scanner. The dual set of images was interpreted blindly by four nuclear medicine physicians. Observer performance with each of the two imaging techniques was evaluated by the receiver operating characteristic (ROC) method and by multivariate information analysis (MIA). Performance was superior for the four observers when interpreting the pinhole images, identification accuracy ranging from 70 to 94% with the pinhole images and only 49 to 63% with the rectilinear scanner.

Bony lesions in systemic mastocytosis: scintigraphic evaluation

Bone, bone marrow and gallium citrate Ga 67 scans were performed on a patient with systemic mastocytosis and bony involvement to evaluate their diagnostic value in such patients. The bone scan revealed increased tracer concentration in the involved areas. These abnormalities were less prominent than those on the roentgenograms, suggesting that only a part of the roentgenographic abnormalities were associated with reactive bone formation. Bone scanning may be less sensitive than roentgenograms to detect the full extent of the bony lesions of systemic mastocytosis. The bone marrow scan revealed a normal central marrow with peripheral marrow expansion. Possibly, the central marrow infiltration by mast cells was sufficient to interfere with its hemopoietic function to a degree that made it necessary to reactivate peripheral marrow tissue. There was no significant 67Ga accumulation in the bony lesions of systemic mastocytosis.