Enhanced detection of metastatic liver disease by computerized flow scintigrams: concise communication.

The purpose of this study was to develop a method by which the sensitivity of radionuclide liver imaging for the detection of hepatic metastasis could be enhanced. Routine flow studies were performed before imaging by injecting the usual 2-3 mCl dose of Tc-99m sulfur colloid as a bolus and storing 30 2-sec images in a computer. With regions selected by light pen, curves were generated from the right lobe of the liver, the right kidney, and the descending aorta. The peak of the kidney curve was chosen as a marker to separate the arterial and venous phases on the liver curve. The average slopes of four points on the liver curve before this marker, and four after, were calculated and the ratio of the first slope to that of the second was defined as the arterialization index. In this study with 228 patients, the inclusion of this index raised the sensitivity from 85 to 100%.

Modified subtotal thyroidectomy in the management of Graves' disease.

A prospective study of a new surgical approach (modified subtotal thyroidectomy) in the management of Graves' disease was carried out in 55 patients. The patients were followed over an average of 4 years with a strict protocol involving serial clinical and chemical evaluations (T4, T3RIA, TSH) and yearly thyroid scans. Long-term euthyroidism was achieved in 94% of the patients. These results are markedly superior to the functional results occurring after the standard thyroidectomy in widespread current use. In particular, the development of postoperative hypothyroidism, which is usually manifest by the second year after operation, has not occurred in this series. Observations of TSH elevations in som euthyroid postoperative patients may have important implications regarding the mechanism by which appropriate surgical resection favorably affects the pathophysiology of Graves' disease.

Radionuclide angiography of the liver and spleen. Noninvasive method for assessing the ratio of portal venous to total hepatic blood flow and portasystemic shunt patency.

Radioactivity verus time curves were generated for the first pass of technetium-99m pertechnetate through the left ventricle, kidneys, spleen and liver, after a 20 mCi peripheral intravenous bolus injection. The rate of change of radioactivity in these organs before recirculation is proportional to blood flow through the organ. The hepatic perfusion index, defined as the ratio of portal flow to total hepatic blood flow, was correlated with the angiographic grade of portal perfusion. The hepatic perfusion index in seven normal subjects was 66.0 +/- 3.4 percent (mean +/- standard error of the mean), and in 22 cirrhotic patients with decreasing angiographic perfusion of grades 1 to 4 the index was 54 +/- 4.6, 37 +/- 2.6, 17 +/- 4.7 and 3 +/- 1.1 percent, respectively. The correlation between the calculated perfusion index and the angiographic grade of portal flow was highly significant (p less than 0.001). The passage of radionuclide through the spleen differed before and after shunt surgery in patients with portal hypertension. The slope to height ratio, based on the downslope of the splenic curve, was significantly greater (p less than 0.01) in the shunted patients and provided a simple index for assessing shunt patency.

Quantitative evaluation of brain edema by radionuclide imaging technique.

The objective of the present investigation was to quantify metabolic cerebral edema in dogs with impaired monoamine oxidase (MAO) function and liver disease using dynamic imaging of the brain with 99mTc-diethylenetriamine pentacetic acid (99mTc DTPA). Data acquisition was started following a rapid intracarotid injection of 99mTc DTPA (5 mCi), and sixty 0.5-s images of the left or right hemisphere were taken. First-pass time-activity curves were obtained by selecting regions of interest for the appropriate brain hemisphere. The results of this study demonstrated that in phenelzine-treated animals there was a 6 to 38% reduction in brain washout slopes of 99mTc DTPA (24.0 +/- 11.5% reduction). These washout slopes were further reduced (range 24.0-86.0; 50.6 +/- 18.5% reduction) following the oral administration of tyramine (1 mg/kg). A significant correlation was noted between changes in washout slopes and the development of coma in these animals.

An improved method of estimating the portal venous fraction of total hepatic blood flow from computerized radionuclide angiography.

The measurement of portal venous flow to the liver is important in the evaluation of patients for shunt surgery. A previous report described a method using slope analysis of hepatic radionuclide angiograms to generate an index of relative portal flow, which correlated well with angiographic grades of portal perfusion. The present report describes a refinement in bolus administration and a modification in technique that appear to reflect true portal venous flow more accurately. A total of 109 studies was performed, including seven normal and 80 cirrhotic patients. The method was reproducible (r = 0.998) and showed good correlation with the angiographic grades of perfusion (r = -0.906).

"Doughnut" sign in brain scanning.

The significance of the "doughnut" sign at present is relegated to characterizing the morphology of a lesion. The use of the "doughnut" sign in differential diagnosis should not be attempted except in specific clinical contexts, and never excluding other evidence. The "doughnut" sign in scanning together with other studies such as angiography and computerized axial tomography gives additional characterizing data in the neuroradiologic evaluation of a patient.

Amputation stumps studied by bone scanning. Work in progress.

Nine diabetic and 7 nondiabetic (post-trauma) patients 24 to 63 years of age (mean, 49) were scanned following amputation below the knee, which was bilateral in 4. A three-phase scanning technique (flow, blood pool, and delayed equilibrium images) was employed, using Tc-99m-etidronate. Duration of the arterial and capillary phases was estimated during flow. Activity at the tip of the stump was plotted as a function of (a) time since amputation and (b) flow measurements. Activity was found to diminish over a period of nearly 50 months, usually becoming minimal or undetectable after 18 months. The stump demonstrated relative stasis compared to the intact limb, particularly in diabetics and patients with long-standing amputation.

Assessment of splanchnic blood flow in alcohol and drug abuse using radionuclide angiography.

Computerized radionuclide angiography (RA) is a noninvasive, quantitative, reproducible, and cost-effective method for measuring the portal venous fraction of total hepatic blood flow (represented by the Hepatic Perfusion Index, HPI), and also can be utilized to detect hemodynamic abnormalities in the spleen. A group of 105 men (aged 20-56) were evaluated at the time of admission to the Substance Abuse Program at the Department of Veterans Affairs Medical Center. These patients were classified into three groups: (a) alcohol dependence or abuse (Group A, n = 54); (b) polysubstance abuse without alcohol (Group B, n = 9); and (c) polysubstance abuse with alcohol (Group C, n = 42). Of the respective groups, 69%, 100%, and 79% had abnormal splanchnic flow (liver and/or spleen), whereas only 43%, 78%, and 48% had abnormal liver function tests. This method may be a sensitive, noninvasive detector of early pathophysiological changes in the splanchnic organs of alcohol and drug abusers.

HIDA scanning and ultrasonography in the expeditious diagnosis of acute cholecystitis.

Radionuclide hepatobiliary imaging (HIDA scanning), a pathophysiologic modality, has become the diagnostic method of choice for suspected acute cholecystitis. The diagnosis is made quickly with this technic, which is simple, safe, and accurate. It is in widespread use and will soon be available for small community hospitals as well as large metropolitan and university centers. Ultrasound, though an excellent anatomic modality for diagnosing cholelithiasis, does not demonstrate the status of the cystic duct, information essential to the diagnosis of acute cholecystitis.

67Ga scintigraphy in postoperative synthetic graft infections.

Postoperative infections of synthetic vascular grafts are seldom diagnosed by conventional radiographic methods, leading to high morbidity and mortality. Gallium-67 scintigraphy was included in the diagnostic evaluation of five patients with suspected vascular graft infections. Abnormal accumulation of the radionuclide around the graft was present in all of these patients who were later determined to have paraprosthetic infections. Gallium-67 citrate scintigrams seem to be diagnostically effective in the difficult problem of paraprosthetic infection.

A noninvasive method for measuring portal venous/total hepatic blood flow by hepatosplenic radionuclide angiography.

Radionuclide angiography was used to generate first-pass radioactivity vs. time curves for the left heart, right hepatic lobe, right lung, spleen, and both kidneys following rapid intravenous injection of 20 mCi (740 MBq) of 99mTc-pertechnetate. Seven normal subjects were examined as well as 57 cirrhotic patients, who also underwent angiographic grading of portal venous perfusion. For analysis, two time points were identified: (a) t0, when 99mTc first entered the liver (the initial rise of either curve); and (b)tc, when 99mTc was maximal in abdominal organs (the renal peak). Analysis was based on the slopes of the two phases of the hepatic curves t0 + 7 seconds and Tc + 7 seconds; this time selection permitted analysis of all curves. The hepatic perfusion index (HPI) = slope (tc + 7 secs)/slope (t0 + 7 secs) + slope (tc + 7 secs). The mean HPI for the normal subjects was 66% +/- 7; for the cirrhotic patients with angiographic Grades I, II, III, and IV, the HPI was 52% +/- 9, 37% +/- 6, 15% +/- 7, and 3% +/- 4, respectively. Correlation between HPI and angiography was significant (p less than 0.001). This method offers a readily available, rapid, relatively inexpensive, and quantitative method of grading the ratio of portal venous to total hepatic blood flow.

Melanoma detection by enzyme-radioimmunoassay of L-dopa, dopamine, and 3-O-methyldopamine in urine.

This enzyme-radioimmunoassay for the measurement of L-dopa, dopamine, and 3-O-methyldopamine is based on the incubation of urine in the presence of catechol-O-methyltransferase, aromatic-L-amino-acid decarboxylase, and S-adenosylmethionine. The O-methylated dopamine metabolite formed, 3-O-methyldopamine, was characterized by radioimmunoassay. To evaluate the role of L-dopa metabolism in melanoma, we used the enzyme-radioimmunoassay to assess concentrations of L-dopa, dopamine, and 3-O-methyldopamine in urine from 10 healthy subjects, 10 hospitalized patients without melanoma and 28 patients with different degrees of melanoma. The effect of surgery for melanoma on urinary output of these catechols of melanoma patients was also evaluated. No significant difference in urinary L-dopa, dopamine, and 3-O-methyldopamine excretion rates was seen between normal subjects (L-dopa 1.3 +/- 0.3, dopamine 147 +/- 38, and 3-O-methyldopamine 31.4 +/- 13.6 microgram/24 h), hospitalized patients without melanoma, and amelanotic melanoma patients. However, the excretion rates for these metabolites in melanotic melanoma (L-dopa 5.6 +/- 1.2, dopamine 555 +/- 121, and 3-O-methyldopamine 178 +/- 40.3 microgram/24 h) were significantly (p < 0.005) higher than in control or amelanotic melanoma subjects. After surgery, there was a substantial decrease in urinary output of L-dopa and its metabolites by these patients.