Age-related alterations in skeletal metabolism--24-hr whole-body retention of diphosphonate in 250 normal subjects: concise communication

Twenty-four-hour measurements of whole-body retention (WBR) of Tc-99m diphosphonate (a sensitive measure of skeletal metabolism) have been obtained in 250 healthy volunteer subjects. WBR values were found to fall from the age of 20 yr until 35 yr and then in men to rise linearly thereafter. Women showed a similar pattern initially but there was a marked rise in WBR corresponding to the menopausal years. Our results lend support to the belief that skeletal metabolism increases with age. It is suggested that some imbalance must always exist between resorption and formation in bone, with net loss of bone mineral, and increasing levels of skeletal metabolism will exaggerate this imbalance and accelerate the rate of bone loss.     

Donor-leukocyte imaging in granulocytopenic patients with suspected abscesses: concise communication

Indium-111-labeled donor leukocytes were used for the detection of foci of suppuration in eight severely leukopenic patients with marrow suppression, either idiopathic or associated with chemotherapeutic regimens for leukemia. In three patients good correlation was found between the results of imaging and clinical signs or subsequent proof of inflammation. In the other five patients, in whom no evidence of localized suppuration occurred, no abnormal accumulations of radioactivity were demonstrable. Labeled donor leukocytes provide a method for locating suppurative foci in severely leukopenic patients in whom autologous leukocyte labeling is impractical.     

Functional asplenia in patients with chronic graft-versus-host disease: concise communication

Liver/spleen images were performed with technetium-99m sulfur colloid in 53 patients who had undergone bone-marrow transplantation. The spleen was not seen in the images in five out of the ten patients with chronic graft-versus-host disease (GVHD). None of the five had a history of splenectomy. In two of these patients, anatomical presence of the spleen had been documented earlier by scintigram. The spleen was visible in all seven patients with acute and in all 36 patients without GVHD. Neither the differences in methods of treating the patients before bone-marrow transplantation nor the time lapse between transplantation and the liver/spleen image correlated with the observed effect among these three groups of transplant patients. We conclude that there is a high association between chronic GVHD and functional asplenia.     

Radiographic and scintigraphic skeletal imaging in patients with neuroblastoma: concise communication

Bone scans, bone-marrow scans, and radiographic skeletal surveys have been reviewed in 40 children with neuroblastoma. Bone scans are the most sensitive method for detecting metastases and should be used first. The additional yield from a skeletal survey is very small, so it should be done only if the bone scan is negative and major therapeutic decisions are to be made. Bone-marrow scans provide a sensitive method of identifying metastases, and may help in staging a patient as stage IV when the bone scan is negative.     

Indium-111 chloride imaging in patients with suspected abscesses: concise communication

Two hundred and fifty-eight patients with clinically suspected inflammatory processes were studied. Seventy-two images were categorized as true positive; 211 as true negative. There were nine false-positive studies, four of which were due to activity in beds of excised organs. There were six false-negative studies, four of which were due to walled-off abscesses found either at surgery or biopsy. The sensitivity was 92%, the specificity 95%, and the accuracy 94%. This study shows that indium-111 chloride imaging provides a reliable way to locate inflammatory processes and overcomes the disadvantages of other imaging agents, for example gastrointestinal activity or the demonstration of healing surgical wounds with gallium-67, and the false-positive images due to cystic fibrosis and other respiratory diseases, or accessory spleens as seen with In-111-labeled white cells.     

Bone scintigraphy in the initial staging of patients with renal-cell carcinoma: concise communication

We reviewed the records of 40 consecutive patients who received bone scintigraphy in conjunction with the initial evaluation and staging of renal-cell carcinoma, to determine the role of bone imaging in this clinical context. Bone scintigrams were positive in three out of 40 patients at the time of diagnosis. In view of the low yield of bone imaging, it appears that routine scintigraphy is unwarranted in the absence of skeletal symptoms before the diagnosis of renal lesions. The presence of a positive bone image did not alter the indication for nephrectomy.     

Xenon-133 retention in hepatic steatosis-correlation with liver biopsy in 45 patients: concise communication

This study presents the results of comparison of hepatic fat content with hepatic xenon retention in 45 patients. The degree of hepatic Xe-133 retention was measured during pulmonary ventilation studies. The amount of hepatic steatosis was graded 0 to 4+ on histologic liver sections obtained by needle or surgical biopsy. There was agreement between the amount of hepatic xenon retention determined scintigraphically and the degree of steatosis determined histologically. These results suggest that Xe-133 retention in the liver provides a simple means of evaluating fatty infiltration of the liver. The potential of this technique as a noninvasive means of investigating hepatic fatty infiltration is discussed.     

Portrayal of pheochromocytoma and normal human adrenal medulla by m-[123I]iodobenzylguanidine: concise communication

The radiopharmaceutical m-[131I]iodobenzylguanidine (I-131 MIBG), which is readily taken up by adrenergic vesicles, produces scintigraphic images of pheochromocytomas in man but rarely visualizes normal adrenal glands. Iodine-123 has many potential advantages over I-131 as a radiolabel for MIBG, including shorter half-life, freedom from beta emissions, and increased gamma-camera efficiency. In this study, diagnostic doses of MIBG labeled with I-131 and I-123, with nearly equivalent radiation dosimetry, were compared as imaging agents in eight patients with known or suspected pheochromocytoma. Images of superior quality were obtained with I-123 MIBG, and lesions not visualized using I-131 MIBG were portrayed. In addition, the normal adrenal medullae were visualized on the I-123 MIBG scintigrams in six out of eight patients.     

Ornithine metabolism in normal subjects and patients with cancer

The metabolism of L-(1-14C)ornithine monohydrochloride was monitored in patients with histologically proven cancer and in normal volunteers. Following i.v. injection of 8 microCi C-14 ornithine (160 nmoles), the decarboxylation of ornithine--yielding 14CO2--was monitored for a 2.5-hr period using the ionization chamber and vibrating-reed electrometer of Tolbert, as modified by Davidson and Schwabe. Twelve normal subjects exhaled 7.3-15.7% of the administered C-14 (mean 12.6% s.d. 3.11%). In ten patients tested before initiation of therapy, recovery ranged from 18.2-32.1% (mean 23.02%, s.d. 4.52%). A t-test indicates a confidence level of > 99.5% that a significant difference exists between the two means. Re-testing of two normal volunteers showed little or no change in ornithine metabolism over a 2-5-mo period. Results from testing three cancer patients before and after therapy correlate well with clinical evidence of the presence of tumor burden.     

Proximal, distal and total stomach emptying of a digestible solid meal in normal subjects

The gastric fundus and antrum probably play different roles in the emptying of solids and liquids in man, but there is little information about the intragastric distribution of food. We have used a new radionuclide technique to quantify proximal, distal and total stomach emptying of a digestible solid meal (100 g of 99Tcm-labelled liver/ground beef given with 150 ml of 10% dextrose) in 13 normal subjects. A proximal reservoir area was seen after consumption of the meal, and used to define the proximal stomach region. A line drawn immediately below this area divided the total stomach region into proximal and distal stomach. Emptying from the total stomach exhibited two phases--an initial lag period (median 41 min, range 21-57 min), followed by approximately linear emptying. Redistribution of food from the proximal to the distal stomach was a major component of the lag period in 11 of the 13 subjects. In the remaining two subjects, redistribution was rapid (proximal 50% emptying time of 4 and 10 min) and antral retention was the major component of the lag period. In seven subjects, a region of reduced activity (contraction band) was seen. The midpoint of this band closely approximated to the line used to divide proximal and distal stomach. We suggest that a contraction band may be responsible for the proximal gastric reservoir seen after meal consumption and plays an important role in the redistribution and emptying of digestible solid food from the stomach. There is considerable variation between normal subjects in the rate of transfer of digestible solid food from the proximal to the distal stomach.     

The specificity of pyrophosphate myocardial scintigrams in patients with prior myocardial infarction: concise communication.

Fifty-five patients with old (9 days to 10 yr) transmural infarcts but with no evidence of recent infarction, were imaged with Tc-99m pyrophosphate. Discrete uptake was rare in the setting of an old infarct. Diffuse uptake was neither sensitive to, nor specific for, acute infarction. Prior infarction will rarely cause diagnostic error if the discrete pattern is required for a positive diagnosis.     

Prolonged iodine clearance with a depletion regimen for thyroid carcinoma: concise communication

Prior studies suggested iodine depletion as a means of enhancing radioiodine uptake into metastases from well-differentiated thyroid cancer. Data are not available regarding the secondary effects of this maneuver on iodine clearance and on total-body radiation. Accordingly we have measured inorganic iodine clearance, total body iodine, tumor and total-body retention of radioactive iodine before and during a diet-and-diuretic regimen designed to induce iodine depletion. Total-body iodine decreased by 25% to 66% (p less than 0.05). The amount of radioiodine taken up and retained by tumor tissue increased 146% (range 48-243%) following the depletion regimen in three studies (two patients). However, because the iodine clearance decreased by 56% (range 40-71%), the total-body radiation per standard 150-mCi dose increased by 68% (range 19-111%). Consequently, the increase in lesion irradiation relative to the increment delivered to the total body was only 46% (range 24-82%). We conclude that iodine-depletion regimens are less effective than prior studies suggest.     

Rectal perchlorate for unconscious patients prior to brain scintigraphy with pertechnetate: concise communication.

Patients undergoing brain scintigraphy with pertechnetate are frequently premedicated with oral perchlorate. However, the oral route is difficult to employ in unconscious or uncooperative patients or when oral intake is restricted. In such situations, rectal administration of sodium perchlorate dissolved in water is an effective alternative to oral administration.     

Dynamic SPECT with Xe-133: regional cerebral blood flow in patients with unilateral cerebrovascular disease: concise communication

To validate xenon-133 dynamic single photon emission tomography (SPECT) clinically, 74 patients were examined. Strictly unilateral cerebrovascular disease was confirmed in 47 patients by clinical history and by transmission computerized tomography (TCT) and contrast angiography. Twenty-seven were excluded, considered normal. SPECT flow maps were evaluated visually (against TCT) or by automated region of interest (ROI) techniques (12 areas per slice) to measure area flow (AF) (ml/100 g-min) and interhemispherical area flow ratios (AR). These were compared with normal values. Minimum AF in affected hemisphere decreased, and AR-to-normal difference increased, with the severity of the disease. Visually, low-flow areas were detected twice as frequently in SPECT as areas of low density of TCT. In reversible episodes, sensitivity of AF alone ws significantly below the sensitivity of combined evaluation of flow and ratio.     

Skeletal scintigraphic changes in osteoporosis treated with sodium fluoride: concise communication

An appendicular skeletal response to sodium fluoride (NaF) was detected by total skeletal scintigrams. Twelve postmenopausal osteoporotic women were treated with NaF (88 mg/day) and calcium (1500 mg/day). Total skeletal scintigrams were obtained before and during treatment. Within 4 to 21 mo (mean: 8.3), all 12 patients showed new areas of increased uptake corresponding to metaphyseal regions and short bones of the appendicular skeleton. The number of peripheral bones involved in each subject ranged from four to 12. The most frequently involved sites (11 of 12 patients) were the right distal femur and proximal tibia. Nine patients showed an increase in serum alkaline phosphatase activity, which was attributed to an increase in the skeletal isoenzyme. Seven of 12 patients developed bone pain in one or more of the regions of increased uptake. This study establishes that the skeletal scintigram is a sensitive index of the peripheral skeletal response to NaF.     

Thyroid iodine content measured by x-ray fluorescence in amiodarone-induced thyrotoxicosis: concise communication

Iodine-induced thyrotoxicosis (liT) is characterized by (a) a low radioiodine uptake, increased by exogenous TSH, and (b) a spontaneous evolution towards cure within a few months. An hypothetical pathogenesis of liT is an initial inflation in the stores of thyroid hormones during iodine excess, followed by their sudden discharge into the circulation. Thyroid iodine content was measured by fluorescent scanning in 10 patients with amiodarone-induced thyrotoxicosis and in various control groups. Results were found to be high at the onset of the disease and to decrease during its course. The data agree with the hypothetical pathogenesis. Furthermore they may permit exclusion of a painless subacute thyroiditis, which is the main differential diagnosis of liT.     

Quantitative autoradiography with radiopharmaceuticals, Part 1: Digital film-analysis system by videodensitometry: concise communication

A simple low-cost digital film-analysis system using videodensitometry was developed to quantitate autoradiograms. It is based on a TV-film analysis system coupled to a minicomputer. Digital sampling of transmitted light intensities through the autoradiogram is performed with 8-bit gray levels according to the selected array size (128 X 128 to 1024 X 1024). The performance characteristics of the system provide sufficient stability, uniformity, linearity, and intensity response for use in quantitative analysis. Digital images of the autoradiograms are converted to radioactivity content, pixel by pixel, using step-wedge standards. This type of low-cost system can be installed on conventional mini-computers commonly used in modern nuclear medical facilities. Quantitative digital autoradiography can play an important role, with applications stretching from dosimetry calculations of radiopharmaceuticals to metabolic studies in conjunction with positron-emission tomography.     

Value of sonographic screening for gallstones in patients with chest pain and normal coronary arteries

The prevalence of sonographically detectable gallstones in patients with chest pain and normal coronary arteries was compared with the prevalence of gallstones in patients referred to sonography for nonbiliary disease. Among 545 patients with chest pain and normal coronary arteriograms, 101 (18.5%) were referred for sonographic examination of the gallbladder. This test group was compared to a matched control group (n = 101) undergoing abdominal sonography for nonbiliary disease. Six patients (5.9%) in the test group and eight patients (7.9%) in the control group were found to have gallstones by accepted sonographic criteria. Studies based on oral cholecystogram screening of healthy populations have claimed a prevalence of cholelithiasis of 2.3%-6.2% for males and 2.3%-12% for females. The authors were unable to demonstrate a higher prevalence of sonographically identified gallstones in patients with chest pain and normal coronary arteries than in patients examined for nonbiliary disease. The frequency of gallstones in this test group is comparable to that reported for a screened population of healthy men and women.