Biomedical subjects
Publications and source records attributed to S Treves.
A case is described in which the preoperative diagnosis of Meckel's diverticulum was made by scintigraphy after the administration of pentagastrin. Pentagastrin premedication may be helpful in demonstrating ectopic gastric mucosa in patients with gastrointestinal bleeding in whom initial radiopertechnetate scintigraphy is equivocal or normal.
Six selected cases demonstrate the appearance of subdural hematomas, tumor, stroke, and abscess on single-photon emission tomography. Conventional radionuclide images were obtained on every patient, and computed transmission tomographs were obtained on 4 of the patients. This early clinical experience suggests several promising areas for further investigation.
Twenty patients with blunt abdominal trauma were diagnosed as having splenic rupture by Tc-99m sulfur colloid scintigraphy. Because of the increased risk of infection in children following splenectomy, surgery was not performed and scintigraphic followup of the injured spleens was carried out. Thirteen patients were scanned at least 2 mo after trauma and the longest followup was 1 yr. Only three spleens showed "scintigraphic healing." The remaining ten showed smaller defects, but in two patients the size of the defect did not change after the 2-mo scan. In no case did the scan defect enlarge. Technetium-99m sulfur colloid scintigraphy offers a convenient and sensitive method of following trauma cases if no surgery is performed. Scintigraphic defects can persist for long periods of time while the patient is asymptomatic.
Thirty-eight corrective operations have been performed in patients with tetralogy of Fallot and a functioning aortopulmonary shunt. There were 3 operative deaths (7.9%) and 1 late death (2.6%), and 3 patients have required reoperation for significant residual defects. Only 1 of 10 patients studied postoperatively by radionuclide scanning has a significant reduction in blood flow to the lung on the side of the closed shunt. We conclude that the presence of an aortopulmonary shunt does not add to the risk of repair in patients with tetralogy of Fallot and that mortality after such operations is related to the complex anatomy often present in patients of this group.
To determine the effects of the pulmonary hypoplasia present at birth in infants with congenital diaphragmatic hernia upon subsequent development of the lung, 19 patients who had undergone surgical repair before the age of one year were studied at ages 6 to 18 years. Total lung capacity and vital capacity averaged 99% of predicted value. Diffusing capacity for carbon monoxide was normal. Forced expiratory volume in one second averaged 89% of predicted value and 80% of vital capacity. Total respiratory system conductance and maximum expiratory flow volume curves obtained during air and helium-oxygen breathing were normal. Xenon 133 radiospirometry performed in nine patients revealed equal distribution of lung volumes on the two sides. Ventilation to the hernia side was reduced in only two patients. Blood flow to the hernia side was reduced in all nine patients. Chest radiographs supported the physiologic observations. These findings are consistent with the persistence of a reduction in the number of branches or generations of pulmonary arteries and bronchi on the side of the hernia. Since a substantial part of the vascular resistance resides in peripheral vessels, this developmental abnormality influences the distribution of pulmonary blood flow, although it has little effect on tests reflecting airway resistance or the distribution of ventilation.
99mTc-methylene diphosphonate, a bone-seeking radionuclide, accumulated in the spleen of a 16-year-old boy with sickle-cell anemia even though no splenic calcification was visible. This may be explained by the presence of microscopic calcium deposits in the spleen, which form at an early age in this disease. Bone-seeking radionuclides may accumulate in regions of recent splenic infarction, as has been demonstrated in cerebral and myocardial infarction. Such radionuclides may be the only means of demonstrating the spleen in such patients.
191mIr is a useful tracer for radionuclide angiocardiography and may be of particular value in the evaluation of heart disease in children. It has a short half-life, a suitable photon energy, and may be obtained as a generator product by decay of its long-lived parent 191Os. A 191Os-191mIr generator capable of providing at least 18 mCi of 191mIr in 1.5 ml of eluant is described. 191mIr is separated from 191Os by absorbing 191OsCl6(-2) on an ion exchange resin and eluting with a solution of 8.7% NaCl at a pH of 2.2. The generator employs an additional resin column which is replaced to minimize 191Os breakthrough.
Paraplegics whose range of motion is limited by para-osteo-arthropathy (POA) may have difficulty in becoming independent unless the heterotopic bone mass is removed. The recurrence rate is high if the bony mass is not mature at the time of surgery. Radiography and alkaline phosphatase correlations are not trustworthy. In 3 paraplegics with POA, radiolabeled osteotropic agents demonstrated a steady decrease in the uptake ratio (heterotopic/normal bone) followed by a steady-state plateau, reflecting the most useful index of maturation and allowing surgical removal of bone without recurrence.
A 99MTc pertechnetate image demonstrated epididymo-orchitis and a hydrocele in a 15-year-old youth with painless scrotal swelling. The differential diagnosis is reviewed.
Thirty-nine ventilation and perfusion lung studies with xenon 313 were perfomed in 29 patients with D-transposition of the great arteries (DTGA). Fifteen patients had simple DTGA and 14 more complex anatomic features. Inequalitiies of ventilation (V) were present in 23% (9/39) and perfusion (Q) in 44% (17/39) of studies. Six patients with simple DTGA showed abnormal distribution of perfusion, all with increased flow to the right lung. Among the 14 patients with complex DTGA, eight (57%) had abnormal distribution of perfusion. In patients with pulmonary artery band, increased flow was directed toward the left lung, and in those with an aorticopulmonary anastomosis, increased flow was to the side of the shunt. Radionuclide angiograms were performed in 17 patients with DTGA, both before and after surgical repair. In all, an abnormal circulatory pattern was noted. Complete superior vena cava obstruction present in four patients and residual left to right shunt (Qp/qs greater than 1.7/liter) in three was confirmed at cardiac catheterization. Ventilation perfusion studies with xenon-313 and technetium-99m radionuclide angiogram were effective noninvasive techniques in assessing pulmonary function and hemodynamics in patients with DTGA.
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Radionuclide angiocardiography is a useful method in the evaluation of patients with congenital heart disease, safely and nontraumatically. Physiologic variables such as transit times, cardiac output, left ventricular ejection fraction, stroke volume, end-diastolic volume can be measured accurately with this technique. An important application of radionuclide angiocardiography in children with congenital heart disease is in the detection, localization and quantification (pulmonary to systemic flow ratio) of intracardiac shunts and shunts between the great vessels. This technique has been found useful in the evaluation of the newborn infant with cyanosis, the patient with a cardiac murmur and the patient who has had cardiovascular surgery. Newer mobile gamma camera-computer systems permit the performance of radionuclide angiocardiography in several ill premature and newborn infants and patients during the early postoperative period. Specially designed magnifying collimators and the development of ultrashort-lived radionuclides should result in an overall improvement in the diagnostic capabilities of this technique and in a further reduction in the radiation dose.
Eight consecutive patients, referred because intravenous urography (IVP) raised the question of hypertrophied septum of Bertin versus a pathologic mass, were examined using 99mTc labeled radiopharmaceuticals with magnification renal scintigraphy. The areas of concern showed a spectrum of activity, from normal to markedly increased, as compared to surrounding tissue. The activity correlated with the size of the mass effect on IVP. Increased resolution provided by pinhole magnification was important in evaluating these patients. We feel that magnification renal scintigraphy is valuable in the evaluation of intrarenal masses.
In 105 patients defection and quantitation of left to right shunts was performed using quantitative radionuclide angiocardiography. The radionuclide angiocardiograms were acquired and analyzed by a gamma camera interfaced to a digital computer system. Pulmonary to systemic flow (Qp/As) ratios were calculated by analysis of pulmonary time-activity histograms using a gamma variate model. All patients were studied with cardiac catheterization, left ventricular angiocardiography and radionuclide angiocardiography. The radionuclide method allowed precise detection and quantitation of left to right shunts with a Qp/Qs ratio of 1.2 to 3.0. There was good agreement between the Ap/As ratio calculated by oximetry at cardiac catheterization and radionuclide angiocardiography (r = 0.94). The information gathered with this nontraumatic method appears sufficiently reliable to be used in the management of patients.
A method is described for measuring left ventricular ejection fraction which uses high frequency computer recording of gamma scintillation camera data and peripheral venous injectinon of technetium-99m as sodium pertechnetate. Data from mechanical model experiments are used to show feasibility of this method. A phantom experiment is described which was used to develop a technique for accurate delineation of the ventricular outline in the presence of background. The left ventricular ejection was measured in 12 patients by radionuclide angiocardiography and biplane cineangiography. Comparison of these two methods gave a correlation coefficient of 0-91. In addition, left ventricular ejection fraction was measured in 34 patients (aged 7 weeks to 18 years) without evidence of cardiac disease using the radionuclide method alone. Average ejection fractions of 0-66 and 0-70 were found for children over 2 years of age and children 2 years of age or younger, respectively. In addition, an interobseerver comparison study was performed with the data from 10 patients, and only small differences were noted (SD 0-025).
Pentagastrin, histalog, glucagon, secretin, and perchlorate were intravenously injected into mice in order to investigate the hormonal regulation of 99mTc pertechnetate uptake by gastric mucosa. Pentagastrin significantly increased uptake; the effect of histalog was weaker. Secretin did not alter the uptake. Glucagon produced some diminution, and perchlorate significantly inhibited gastric uptake. Hormones may play a role in improving the sensitivity and specificity of diagnostic tests for Meckel's diverticulum.
Iridium-191m is a potential tracer for angiocardiography and may be of particular value in the evaluation of heart disease in children. It possesses a short half-life (4.9 sec), suitable photon energy (129 keV) and may be obtained as a generator product by decay of its long lived (15.3 day) parent 191 Os. An 191Os leads to 191mIr generator capable of providing 15 mCi of 191mIr in 1.5 ml of eluant is described. The separation of 191mIr from 191Os is achieved by absorbing 191OsC16-2 on an anion exchange resin. The generator employs an additional resin column which is replaced to prevent 191Os breakthrough to become excessive. By this procedure, the breakthrough may be kept below 0.001% over a period of at least one month and after multiple elutions.
Traumatic cerebrospinal fluid fistulas in children are not rare as described by Harwood-Nash and Caldicott, North, and Simpson. Those involving the sphenoid bone apparently are rare, particularly in early childhood.