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Biomedical subjects

S T Treves

Publications and source records attributed to S T Treves.

At least 73 records · Page 4Linked to original sources
PubMed1995

The value of bronchodilator administration in asthmatic patients before lung imaging.

A 17-year-old boy with chest pain and severe bronchospasm underwent lung imaging to exclude pulmonary embolism. This showed widespread nonsegmental defects in both the ventilation and perfusion scans. A repeat study performed immediately after nebulized bronchodilator administration was normal apart from changes consistent with left lower lobe pneumonia and atelectasis which had subsequently evolved on the chest radiograph. Bronchodilator administration is valuable in improving the accuracy of lung scanning in asthmatic patients by reducing the perfusion and ventilation abnormalities caused by hypoxia-induced vasoconstriction.

Adolescent↗
PubMed1995

Osteomyelitis and septic arthritis in children: appropriate use of imaging to guide treatment.

Modern imaging techniques have become essential components of the management of acute osteomyelitis and septic arthritis in children. This article addresses the role of these techniques, based on clinical practice guidelines recently developed at a children's hospital by an interdisciplinary group. The recommendations reflect a review of the literature and an analysis of our own experience with 84 children treated for musculoskeletal sepsis during the past 3 years. We attempt to optimize imaging resources by analyzing the unique aspects of these infections in the pediatric skeleton, the clinical needs at different stages of the disease, and the relative strengths and weaknesses of the various imaging procedures. Our goal was to define the use of imaging in cases of osteomyelitis and septic arthritis in children in specific clinical scenarios in which additional information is likely to lead to management modification.

Acute Disease↗
PubMed1995

Single-photon emission computed tomography (SPECT) in pediatric epilepsy.

Single Photon Emission Computerized Tomography (SPECT) is a valuable tool in the assessment of epileptic patients. Radiotracers that distribute according to regional cerebral blood flow permit the identification of altered perfusion to an epileptogenic zone both ictally and interictally. This technique has proven especially useful in temporal lobe epilepsy.

Adolescent↗
PubMed1995

The radionuclide salivagram in children with pulmonary disease and a high risk of aspiration.

Purpose. We wanted to demonstrate the utility of the radionuclide salivagram in assessing children whose underlying medical problems suggest that aspiration of oral contents is a factor contributing to otherwise unexplained lung disease or recurrent pneumonias. Materials and methods. Following sublingual administration of 300 μCi (11.1 MBq) of technetium-99m sulfur colloid in a drop of saline, serial images were obtained for 60 min and evaluated for entrance of tracer into the major airways and lung parenchyma. Thirty-four studies were performed on 31 patients (age: 3 weeks - 16.7 years, mean 5.5 years) with recurrent pneumonias or unexplained lung disease. All had medical conditions, most frequently neurological, predisposing to aspiration. Results. Pulmonary aspiration was detected in eight patients. All positive studies demonstrated aspirated tracer distal to the tracheal bifurcation, either in bronchi or in bronchi and lung parenchyma. Aspiration was bilateral in six cases. Clearance of aspirated tracer was noted in one patient. Conclusion. The salivagram is an effective tool for demonstrating aspiration of oral contents and the level to which aspirated fluid penetrates the tracheobronchial tree. Additionally, by allowing for the evaluation of clearance of aspirated tracer, the salivagram may provide information on the status of airway-protective mechanisms.

Bronchi↗
PubMed1995

Neuroblastoma presenting clinically as hip osteomyelitis: a "signature" diagnosis on skeletal scintigraphy.

At their initial emergency room presentation, four children were thought to have hip osteomyelitis. Skeletal scintigraphy, however, demonstrated multiple areas of abnormal tracer uptake in the bones in all four, and in three there was abnormal uptake in a soft tissue abdominal mass. The skeletal scintigraphic findings promptly led to the correct diagnosis of neuroblastoma.

Adrenal Gland Neoplasms↗
PubMed1994

Myocardial perfusion, function and exercise tolerance after the arterial switch operation.

OBJECTIVES: This study was conducted to determine the prevalence of myocardial perfusion abnormalities at rest and exercise and to assess exercise capacity in children after the arterial switch operation. BACKGROUND: There have been sporadic reports of myocardial ischemia or sudden death in children after the arterial switch operation for transposition of the great arteries, possibly related to inadequate coronary perfusion due to kinking or stenosis of the translocated coronary arteries. METHODS: Myocardial perfusion at rest and peak exercise was assessed using the scintigraphic agent technetium-99m methoxyisobutyl isonitrile (sestamibi). Exercise capacity was determined with a modified Bruce protocol. Ambulatory electrocardiographic (ECG) Holter monitoring was performed. Ventricular function, contractility and wall motion were assessed echocardiographically. RESULTS: Twenty-three children (aged 4.2 to 7.9 years) underwent evaluation. Abnormalities were found on the rest perfusion scans in 22 children (95.6%). The left ventricular myocardium was divided into 13 segments for analysis. Of 299 rest segments, 225 (75.3%) were normal, 11 (3.7%) showed mild defects, 45 (15%) moderate defects and 18 (6%) severe defects at rest. At peak exercise, 237 segments (79.3%) were normal, 24 (8%) showed mild defects, 33 (11%) moderate defects and 5 (1.7%) severe defects. Compared with rest studies, myocardial perfusion grade at exercise was unchanged in 246 segments (82.3%), improved in 42 (14%) and worsened in 11 (3.7%). All patients had normal exercise tolerance without symptoms or ischemic ECG changes. No ventricular tachycardia was seen on Holter monitoring. All patients had a shortening fraction > or = 27%. Left ventricular contractility was normal in 12 children in whom it was assessed. Regional wall motion was normal in 17 children with adequate echocardiographic images for this analysis. CONCLUSIONS: Myocardial perfusion scan abnormalities assessed by technetium-99m sestamibi are common after an arterial switch operation. These abnormalities are of uncertain clinical significance and generally lessen with exercise. The normal exercise tolerance without symptoms or ECG changes suggests that myocardial perfusion is adequate during the physiologic stress of exercise in children up to 8 years after an arterial switch operation.

Child, Preschool↗
PubMed1994

Regional cerebral perfusion abnormalities after cardiac operations. Single photon emission computed tomography (SPECT) findings in children with postoperative movement disorders.

Despite the clinical and pathologic indicators implicating injury to the basal ganglia in children with hyperkinetic movement disorders, we were previously unable to identify lesions in these structures by means of cranial computed tomography or magnetic resonance imaging. We evaluated regional cerebral perfusion measured by single photon emission computed tomography (SPECT) with technetium 99m hexamethyl propylene amine oxime as a technique to localize functional cerebral abnormalities in eleven children who had a movement disorder after hypothermic cardiac surgery. Perfusion defects of the deep gray matter were noted in six of these eleven patients and cortical perfusion defects in nine. For both cortical and subcortical defects a strong right-sided predilection was present. Our findings suggest functional brain injury not detectable by conventional cranial computed tomography and magnetic resonance imaging in these patients. We speculate that these perfusion defects might relate to the behavioral and developmental sequelae in survivors of this syndrome. SPECT may identify subclinical injury in patients at risk for future neurodevelopmental problems and contribute to our understanding of the mechanisms of cerebral injury in the patient operated on for cardiac disease.

Brain↗
PubMed1993

Gallium scanning in children with fever of unknown origin.

Scintigraphy with Gallium 67 is frequently used in the evaluation of children with fever of unknown origin (FUO). Its usefulness in this setting, however, has not been definitely established. We reviewed the clinical records and imaging studies of 30 children with FUO who had Gallium scans. We defined FUO as a febrile illness of greater than two weeks duration which remained undiagnosed after initial clinical, laboratory and radiographic evaluation. 4 of 30 children had positive Gallium scans. Of 25 children with only systemic signs and symptoms in addition to fever, 1 had a positive scan. Of 5 children with more focal complaints, 3 had positive studies: all had localized infections which had remained occult despite imaging with other modalities. We conclude that in most children with FUO, who have only systemic complaints, Gallium scanning is rarely useful. It may be very helpful, however, when there is a suspicion of localized infection, even if other imaging studies are negative.

Adolescent↗
PubMed1993

Brain single-photon emission computed tomography for behavior disorders in children.

Single-photon emission computed tomography (SPECT) of the brain has been used to define functional abnormalities in two groups of childhood behavior disorders: (1) a "primary" category in which there is exclusive or predominant presentation with cognitive and/or behavioral dysfunction and (2) encephalopathies, often defined etiologically at the biochemical or molecular level, in which clinical expression includes, but is not confined to, neural dysfunction. Radiopharmaceuticals available for such studies are manifold, but those used to date have been predominantly perfusion agents, eg, Xenon-133 (133Xe) and technetium-99m (99mTc) hexamethylpropylene amine oxime, and studies with [99mTc]bicisate are eagerly awaited. Xenon-133 studies require that the patient be in the field of view of the detector while the tracer is administered. This renders it difficult for a subject to perform cognitive and other exercises while being imaged, because the environment is quite foreign. On the other hand, the 99mTc-labeled perfusion agents permit a scintigraphic "snapshot" of regional cerebral blood flow during a behavioral event without having to have the patient under the imaging instrument. Thus, one can separate the administration of the radiotracer, which can be done under more controlled and physiological conditions, from the actual imaging. In addition, greater spatial resolution is achieved with the technetium-based agents. Currently, multidetector or dedicated annular crystal-type cameras are the preferred brain SPECT devices, and they are essential to applications such as cortical "activation mapping" or tomographic detection of receptor systems. Close attention to technical detail and standardization of the child's behavioral environment during the investigation are critical to a successful study. The relative advantages and disadvantages of qualitative versus semiquantitative analysis of imaging date are reviewed. Among primary behavioral disorders, 133Xe SPECT studies in attention deficit disorder-hyperactivity (ADHD) have suggested a pattern of hypoperfusion of striatal and periventricular structures with sensorimotor cortical hyperperfusion. This pattern is consistent with some neurophysiological models of the disorder. In cerebral palsy, perfusional abnormalities have paralleled clinical deficits and may offer information to help predict outcome. The important field of childhood affective disorders (schizophrenia, juvenile autism, depression, etc) remains largely unstudied with SPECT. Finally, representative examples of the use of SPECT to study perfusion in encephalopathies with behavioral expression (phenylketonuria, MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) syndrome, Wilson's disease, etc) are given.

Adolescent↗
PubMed1993

Silent renal damage in symptom-free siblings of children with vesicoureteral reflux: assessment with technetium Tc 99m dimercaptosuccinic acid scintigraphy.

Sixteen symptom-free siblings of children with vesicoureteral reflux were found to have the condition and underwent renal scintigraphy with technetium 99m dimercaptosuccinic acid. Of these 16 children, 6 had scintigraphic evidence of renal damage. Screening for vesicoureteral reflux in siblings of children known to have the condition should therefore be carried out early in life; when reflux is present, an immediate assessment of the renal parenchyma should be made.

Child↗
PubMed1993

Thallium-201 versus technetium-99m-MIBI SPECT in evaluation of childhood brain tumors: a within-subject comparison.

We previously found that 201TI SPECT is a highly specific agent for detection of metabolic activity of childhood brain tumors. To compare the relative diagnostic accuracy of 201TI and a technetium-based tumor-avid agent, we have obtained SPECT in 19 children using 201TI (37-111 MBq) followed immediately by 99mTc-methoxyisobutylisonitrile (MIBI) (370-740 MBq) intravenously. Moderate to intense focal uptake of both tracers characterized true positive cases (n = 6). Lesion boundaries were better defined by MIBI. Uptake of MIBI by choroid plexus occurred despite pretreatment with potassium perchlorate (6 mg/kg) and complicated interpretation of deep/paraventricular lesions. Preliminary assessment indicated sensitivity approximately 67% (TI and MIBI); specificity approximately 91% (TI); approximately 100% (MIBI). Two tumors (medulloblastoma, dysgerminoma) were TI/MIBI nonavid. Semi-quantitative assessment of tracer uptake was made using a ratio of radioactivity in tumor-containing areas compared to uninvolved brain. Ratio values were (mean +/- s.d.) 7.88 +/- 7.70 (TI) and 27.1 +/- 36.41 (MIBI). The spectrum of tumor avidity is similar for TI and MIBI. Clearer identification of boundaries by MIBI may be an advantage in applications, e.g., radiotherapy port planning.

Brain Neoplasms↗
PubMed1993

Accelerated renovascular hypertension following angioplasty. Assessment of therapy by Tc-99m DMSA imaging.

This is a report of serial Tc-99m DMSA renal imaging on a pediatric patient with renovascular hypertension that experienced a complication of angioplasty. The case dramatically illustrates the usefulness of this radiopharmaceutical in the evaluation of acutely worsening hypertension, and in monitoring improvement following arterial revascularization for significant branch stenosis.

Angioplasty, Balloon↗
PubMed1993

Nuclear medicine in the pediatric chest.

Nuclear medicine enables functional evaluation of organ systems not possible with standard anatomic imaging modalities. The pathophysiology necessitating scintigraphic examination of the pediatric patient is often different from that in the adult and therefore calls for new or modified applications of nuclear medicine. This article briefly reviews such application, with the scope limited to the evaluation of the pediatric chest and organ systems.

Bone and Bones↗
PubMed1992

Iodine-123 scintigraphy in the evaluation of pediatric thyroid disorders: a ten year experience.

Few studies have been published that describe the role of scintigraphy in the evaluation of the spectrum of pediatric thyroid disorders. Between 1978 and 1987, we studied 280 children with iodine-123 (123I) scintigraphy. Clinical information and follow-up were available in 246. We analyzed the indications for referral and determined whether the information obtained with this technique was useful in subsequent management. Indications for scintigraphy included hypothyroidism, neck masses, hyperthyroidism, and miscellaneous reasons. Scintigraphy was helpful in distinguishing anatomic from functional causes of hypothyroidism. It reliably identified the location of the thyroid gland in patients with neck masses. The functional status of thyroid nodules was readily assessed and was important in directing further treatment. Scintigraphy added little to the management of children with post-irradiation hypothyroidism without a palpable nodule, patients with Hashimoto thyroiditis or Graves disease when the clinical diagnosis was straightforward.

Child↗