Sigmoid augmentation artefact in skeletal imaging.
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Aged↗
Biomedical subjects
R J Boudreau
Publications and source records attributed to R J Boudreau.
Detection of abdominal hemangiomatosis during technetium-99m DTPA renal imaging.
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Abdominal Neoplasms↗
The significance of poor renal transplant concentrating ability as assessed by I-131 Hippuran imaging.
A pattern of very poor renal allograft concentration of I-131 Hippuran and good bladder activity has been observed by the authors. The kidneys are typically barely visualized and the renogram curve is flat. The significance of this particular finding has not been described in the literature. Accordingly, a retrospective review of all patients exhibiting this scan pattern was performed and the authors attempted to correlate it with clinical, laboratory, and pathological findings at the time of study. Of 11 patients exhibiting this scan pattern, three had very high urine outputs at the time of study. Of the remaining eight patients, five had chronic rejection. In the remaining three patients, the diagnosis was: one each, acute rejection, mixed acute and chronic rejection, and cyclosporine toxicity. The authors conclude that although this pattern is non-specific, if the patient is not in a high output state, it is usually related to chronic rejection.
Adult↗
Hepatocarcinoma in association with the Alagille syndrome.
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Abnormalities, Multiple↗
Clinical comparison of high-resolution with high-sensitivity collimators in low-count cardiac gated blood pool studies.
We compared high-sensitivity (HS) and high-resolution (HR) collimators for 2.5-minute low-count acquisitions in 13 patients undergoing cardiac gated blood pool studies. High-count acquisitions served as standards. Ejection fractions calculated from low-count acquisitions were plotted against high-count acquisitions for each collimator; the variance of the HS plot was lower, and HS images were superior.
Adult↗
Suppression of plasma renin activity by cyclosporine.
Cyclosporine treatment is associated with hypertension and suppression of plasma renin activity, the causes of which are unclear. To determine whether suppressed plasma renin activity is due to extracellular fluid volume expansion, 10 cyclosporine-treated renal transplant recipients were compared with 10 azathioprine-treated renal transplant recipients and seven patients with renal insufficiency. Glomerular filtration rate and effective renal plasma flow were significantly lower in cyclosporine-treated patients than in azathioprine-treated patients. Upright plasma renin activity was suppressed in cyclosporine-treated patients (cyclosporine 2.9 +/- 0.9, azathioprine 4.7 +/- 0.9, renal insufficiency 5.2 +/- 1.9 ng/ml/hour) but could be stimulated by a four-day period of dietary sodium restriction and diuretic administration (cyclosporine 15.8 +/- 4.4 ng/ml/hour). Extracellular fluid volume tended to be higher in cyclosporine-treated patients (cyclosporine 30.7 +/- 2.3, azathioprine 26.7 +/- 2.5, renal insufficiency 25.5 +/- 1.4 percent lean body mass), although the difference between cyclosporine-treated and azathioprine-treated patients did not attain statistical significance. There were no differences in the urinary excretion of prostaglandin E2 or 6-keto prostaglandin F1 alpha between the two groups of renal transplant recipients. It is concluded that suppression of plasma renin activity by cyclosporine is physiologic and may reflect expansion of extracellular fluid volume, which can be reversed by sodium depletion.
6-Ketoprostaglandin F1 alpha↗
Functional imaging of the heart.
The generation of functional images from the time-activity curves of individual pixels in the gated blood-pool study has become a routine part of most nuclear medicine computer systems. These images have the advantage of extracting useful functional information from the entire study and presenting it in an easily interpretable format. One can rapidly examine them, especially the phase and amplitude images, to seek out potential abnormalities of contraction and conduction. These are not designed to be "stand alone" images and correlation with the remainder of the study, including the cine display, is required. In addition to their use in assessing abnormalities of either ventricular chamber, they also have been shown to be useful in delineating atrioventricular borders in both the left and right sides of the heart. This facilitates definition of regions of interest for the calculation of ejection fractions. These images are produced at no increased expense or inconvenience to the patient and therefore should always be evaluated.
Heart↗
Exercise-induced muscle uptake of technetium-99m MDP.
Intense muscle localization of Tc-99m MDP to upper extremity musculature was noted three days following weight lifting exercises. This phenomenon is due to an unknown mechanism although several causative factors have been suggested.
Adult↗
Improved prediction of thyroid lobar mass from parameters obtained by routine thyroid scintigraphy.
Estimation of thyroid mass both from parameters derived from thyroid scintigraphy and clinical palpation for purposes of therapeutic dosimetry has not been tested for accuracy. To more precisely determine thyroid mass 90 thyroid lobes from 45 autopsies without history of thyroid disease were studied. Specimens were dissected free of nonthyroidal tissue and assessed for volume, maximum depth (D), width (W), length (L) and mass (M). Using a linear regression model and applying known lobar depth, the most accurate formula to predict true lobar mass (in grams) was 4.9D + 0.07L2W-2.3 (in cms). Length and width would be obtainable in vivo from routine scintigraphic measurements (in cm) and depth would be most accurately determined by ultrasound. For most clinical circumstances where lobar depth is unknown we found the best formula for mass (g) to be 0.1L2W (in cm).
Humans↗
Nonfunctional photomultiplier tubes can produce subtle total-body scan defects.
Nonfunctional photomultiplier tubes produce subtle total body scan defects. The resultant scan shows bands of reduced activity which are far less obvious than those seen on a standard image.
Humans↗
Skeletal imaging after pleurodesis.
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Adenocarcinoma↗
Comparison of the biodistribution of manganese-54 DTPA and gadolinium-153 DTPA in dogs.
The biodistribution of [54Mn]DTPA and [153Gd]DTPA dimeglumine were investigated and compared following i.v. administration to fasting anesthetized dogs. Unlike most previously reported metal ion-DTPA complexes, [54Mn]DTPA showed high uptakes in several organs including the liver, bile, pancreas, bowel, and kidney. This uptake was independent of the pH of the injected solution. Accumulation in these organs suggests a potential role for [Mn]DTPA as a paramagnetic contrast agent for NMR imaging. With the exception of the kidneys, [153Gd]DTPA showed no evidence of tissue specific uptake over the course of 4 hr, consistent with it being an extracellular ion that is cleared by glomerular filtration.
Animals↗
Airflow measurement inaccuracies in aerosol imaging.
Aerosol production using inclined compressed air tanks may be subject to error caused by airflow meter variability and by the degree of inclination of the air-flow meter. Since most of these tanks are used in an inclined position, it is important for clinicians to be aware of these errors.
Aerosols↗
The preliminary evaluation of Mn DTPA as a potential contrast agent for nuclear magnetic resonance imaging.
The pharmacokinetics of 54Mn administered as Mn-diethylenetriamine pentaacetic acid (DTPA) are being investigated to determine if tissue-specific uptake of manganese could be observed while increasing urinary excretion. This chelation and increased excretion should reduce toxicity. In order to obviate the need for repetitive quantitative nuclear magnetic resonance imaging (NMR) we have substituted tracer amounts of a radioisotope of manganese, Mn-54, for the stable ion. By 6 hours, 58 +/- 7% of the injected dose had been excreted in the urine. Peak liver accumulation occurred within 30 minutes (0.50 +/- 0.14% injected dose/g X kg body weight). The pancreas also showed a relatively high accumulation of tracer (0.25 +/- 0.04%/g X kg body weight), reaching a peak at 4 hours. The pancreas to liver ratios were highest at 6 hours (0.7). There was also a substantial accumulation of the manganese in bile. The blood concentration fell very rapidly with little tracer remaining in the blood at 1 hour. Based on these pharmacokinetics, imaging experiments were conducted before, immediately after, and 9 or 24 hours postinjection. These images showed enhanced kidneys and, later (at 9 hours), an excellent parenchymal-collecting system differentiation. The gallbladder was negatively enhanced. The liver showed either increased or decreased signal strength relative to skeletal muscle depending on the pulse sequence used. We conclude that Mn++, administered as Mn-DTPA, merits further investigation as an NMR contrast agent.
Animals↗
Scintigraphic evaluation of liver transplant function.
Since the initiation of liver transplantation at our institution 9 yr ago, 73 patients ranging in age from 8 mo to 64 yr have undergone this procedure. In the immediate postoperative period and at various times thereafter as deemed necessary, radionuclide studies were performed using one of the iminodiacetic acid (IDA) derivatives labeled with 99mTc. Initially, these studies were performed using labeled PIPIDA with a shift to diisopropyl IDA when this latter agent became available. The IDA agent is administered as a bolus so that the "flow" and "pooling" may be viewed immediately after injection. This is followed by sequential imaging at various times up to 24 hr, with optional graphic tracings of hepatic and bowel patterns of uptake and clearance of radioactivity. An analysis of the initial portion of the IDA scan yields useful information regarding the arterial and portal venous supply of the liver. The rapidity of hepatic concentration and excretion provides a direct measure of hepatocyte function which is particularly helpful when used sequentially to follow the response of the liver to therapy for rejection or infection. The study is also used to assess the biliary system for obstruction or leaks.
Adolescent↗
Aerosol penetration ratio: a new index of ventilation.
Superimposition of nuclear medicine scintigrams and standard radiographs provides a unique opportunity for merging functional information intrinsic to nuclear medicine images with the high resolution anatomic detail of radiographs. A newly developed image processing system allows the merging of two separate films of greatly varying sizes to form a single composite image. Subsequent quantitative analysis of the composite image may be performed. Using the superimposition technique, [99mTc]DTPA aerosol ventilation scans (4.5 X 4.5 cm) were superimposed upon chest radiographs (35.6 X 43.2 cm) in 17 cystic fibrosis (CF) patients. Subsequent quantification of the area of nuclear scan ventilation and the radiographic lung area was then performed. A new quantitative radiologic index of ventilation, the aerosol penetration ratio (APR), was defined. Linear correlation of aerosol penetration ratio with residual volume (RV) as percent of total lung capacity (TLC) measured by body plethysmography was good. We conclude that the APR has validity as a physiologic parameter which localized regional excessive residual volume and correlates well with RV/TLC, the "gold standard" pulmonary function index of obstructive airway disease.
Adolescent↗
Clinical use of indium-111 labeled blood products.
Following the introduction of In-111 oxine as a label for blood cells by McAffee and Thakur in 1976, these procedures have become increasingly important in the practice of nuclear medicine. Of particular interest are studies involving the use of labeled leukocytes for the detection of focal infection. The clinical utility of labeled platelets is less well developed, although the use of platelets to detect the formation of thrombi in blood vessels and on vascular grafts and prostheses is gaining prominence. This report summarizes the techniques presently employed at the University of Minnesota for the labeling of blood products, and their clinical use. Consideration also is given to the desired expertise and cost factors involved in the labeling of leukocytes and platelets.
Abdomen↗
Effect of ethanol on droplet size, efficiency of delivery, and clearance characteristics of technetium-99m DTPA aerosol.
With recent technical advances in aerosol technology, the study of regional ventilation using [99mTc]DTPA aerosol has become increasingly popular. Using a cascade impactor, we have assessed droplet size distribution from a newly designed nebulizer. Delivery efficiency of [99mTc]DTPA aerosol to normal subjects was improved 70% with a 10% concentration of ethanol in the nebulizer. Using filter paper fixed to the delivery end of the aerosol device, and varying ethanol concentrations from 0-10%, an 87% increase of deposited radioactivity is measured. Use of higher concentration of ethanol to the nebulizer solution did not further improve delivery efficiency. The addition of ethanol did not alter clearance characteristics of [99mTc]DTPA from the lung nor did it affect droplet size distribution.
Adult↗