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Biomedical subjects

D L Gilday

Publications and source records attributed to D L Gilday.

At least 73 records · Page 4Linked to original sources

Fourier multiaperture emission tomography (FMET).

We describe a new emission tomographic technique, using an Anger scintillation camera and a new family of coded apertures, in which a noniterative computer algorithm is used to reconstruct multiplanar images. The novel feature is a set of spatial narrow band filters that allow the depth information to be separated in the frequency domain. The position of the reconstructed planes can be selected at will. Using this technique, a planar resolution of 0.75 cm and a depth resolution of 1.6 cm have been measured at a depth of 10 cm and a magnification of 1. To demonstrate the potential of this system, the results of a phantom study are reported.

Fourier Analysis↗

Thallium-201 myocardial imaging in anomalous left coronary artery arising from the pulmonary artery. Applications before and after medical and surgical treatment.

Thallium-201 myocardial imaging was performed on six patients with an anomalous left coronary artery arising from the pulmonary artery. Initial images in three children (aged 4 months, 12 months and 2 1/2 years, respectively) demonstrated anterolateral perfusion defects in agreement with the electrocardiographic localization of infarction. Repeat imaging in two patients 2 to 3 months later, after clinical improvement with anticongestive therapy, demonstrated a reduction in the perfusion defect. In 3 other patients (aged 16, 16 and 20 years, respectively) thallium-201 scans performed during exercise stress demonstrated normal myocardial perfusion 7 to 15 years after operation (ligation of anomalous left coronary in two, ligation plus bypass graft in one). Thallium-201 imaging appears to be helpful in monitoring changes in myocardial perfusion before and after medical or surgical treatment of an anomalous left coronary artery, and may shed light on the pathophysiology of the defect. A possible practical limitation of thallium-201 imaging in this condition is the difficulty of imaging subendocardial infarction.

Adolescent↗

Splenic trauma--nonoperative management and long-term follow-up by scintiscan.

1972 TO April, 1977, 28 children with splenic rupture were managed nonoperatively. The diagnosis was confirmed by splenic scintigraphy with 99mTechnetium-sulfide colloid. Those patients whose condition was stable and satisfactory or maintained stable with intravenous fluids or blood transfusions were not operated upon. All patients sustained their ruptured spleens as a result of trauma, except for one spontaneous rupture in a patients with infectious mononucleosis. Emergency laparotomy for deterioration of clinical condition or late complications was never necessary. Splenic scans were repeated in 22 patients to assess resolution. Fourteen patients had minimal residual defects but there were no late complications detected.

Abdominal Injuries↗

The spectrum of intervertebral disc-space infection in children.

Discitis, intervertebral disc-space infection, and vertebral osteomyelitis form a spectrum of disorders with a probably common bacterial etiology. We studied forty-one children who had symptomatic narrowing of the disc space associated with fever and an elevated erythrocyte sedimentation rate and found that the diagnosis of infection in the spine was usually delayed. Technetium 99m polyphosphate bone-scanning proved to be an accurate, rapid, and safe method of establishing an early diagnosis of infection. A positive culture of blood or biopsy material was found in 34 per cent of all the patients (half of the patients for whom cultures were obtained). The clinical and roentgenographic picture that develops is determined both by the virulence and extent of infection and by the resistance and regenerative capacity of the host. Discitis in children is a vertebral osteomyelitis with disc involvement.

Abdomen↗

Cerebrovascular disease in childhood.

Cerebrovascular disease was reviewed in 92 suspected or proved pediatric cases. In addition to the classical adult patterns of the disease, a separate group of patterns occurs in children and infants who suffer a severe transient episode of cerebral hypoxemia. The patterns in the newborn are periventricular increase, laminar cortical necrosis, watershed infarct, rapidly clearing infarct, and diffuse increase. Bilateral extensive patterns correlate well with an ensuing generalized neurological deficit, and localized patterns with a focal deficit. The mixed and diffuse patterns were found to be the most common.

Arterial Occlusive Diseases↗

Radionuclide skeletal survey for pediatric neoplasms.

A prospective study comparing the radionuclide skeletal survey with the radiographic survey was performed for 159 children with known primary neoplasm. Forty-four showed radionuclide evidence of metastases, while only 14 had radiographic evidence. Thus, 68% of metastases were discovered by bone imaging alone. No false negative images for metastases were obtained, though there was one false negative image for primary tumor. Radionuclide skeletal survey is recommended as the primary evaluation for bony metastases in all children with neoplasms. Suspect areas should then receive complete radiographic examination.

Adolescent↗

Benign bone tumors.

There is little information in the literature concerning the role of bone scanning in benign bone neoplasms except for sporadic reports. Since the advent of 99mTc-polyphosphate, bone imaging has proven feasible and useful in locating the cause of bone pain, such as in osteoid osteomas, which are not always radiologically apparent, and in evaluating whether or not a radiologic lesion is indeed benign and solitary. Blood-pool images are particularly important in neoplastic disease, since the absence of hyperemia in the immediate postinjection period favors the diagnosis of a benign neoplasm, as does low-grade uptake on the delayed study. The scan, including pinhole magnification images, is especially valuable in diagnosing lesions in the spine and pelvis, which are poorly seen radiologically. We have studied various types of benign bone tumors, including simple and aneurysmal bone cysts, fibrous cortical defects, and nonossifying fibromas, all of which had minimal or no increased uptake of the radiopharmaceutical, unless traumatized. Although osteochondromas and enchondromas showed varied accumulation of activity, the scan was useful in differentiating these from sarcomatous lesions. All osteoid osteomas demonstrated marked activity, and could be accurately located preoperatively, as could the extent of fibrous dysplasia. The bone scan in the reticuloses also showed abnormal accumulation of activity, and aided in arriving at the prognosis and treatment of histiocytic bone lesions.

Bone Cysts↗

A new approach to the diagnosis of testicular torsion.

The acutely painful, enlarged scrotum has necessitated urgent exploration of the scrotum so as not to miss testicular torsion. This has led to unnecessary operations. The urgency with which the diagnosis is made is particularly important in infants and children for in these patients the signs and symptoms of testicular torsion may be minimal. Since its introduction in 1973, scrotal scanning has allowed a precise evaluation of the testicular perfusion and thus refined the indications for operation. Using scrotal scanning in a series of 18 patients with possible testicular torsion a correct assessment of testicular perfusion was made in every patient. In only two patients did the interpretation differ from the ultimate clinical impression. In one, the torsion had relieved itself before the scan was performed and at operation the testis had adequate perfusion. In the second, clinically suspected epididymitis was not confirmed. Because of the ease and rapidity with which the test may be done in children more testes should be salvaged with fewer negative explorations.

Adolescent↗

Computed tomography in infants and children: intracranial neoplasms.

Cranial CT proved exceptionally accurate in detecting and localizing cerebral neoplasms in children, with only one false negative case in 40 tumors. CT had its greatest diagnostic value in cerebral and cerebellar hemispheric lesions, tuberous sclerosis, and as a screening device for craniopharyngiomas. While CT may provide a definitive diagnosis, additional information form other neuroradiologic studies is often necessary.

Brain Neoplasms↗

Value of routine cerebral radionuclide angiography in pediatric brain imaging.

In addition to static brain images, cerebral radionuclide angiograms (CRAGs) were performed in 1,051 children to determine the value of routine radionuclide angiography. The CRAG resulted in a statistically significant increase in detection of abnormalities (p less than 0.01), as it provided the only evidence of confirmed abnormalities in 60 children (5.7%). The CRAG helped detect subdural fluid collections, cerebrovascular disease, and cerebral cysts, but it was of little value in detecting hydrocephalus. For maximum diagnostic yield, a CRAG should be performed with all pediatric brain-imaging studies.

Brain Diseases↗

Dural fluid collections in infants and children. A successful nuclear medical approach.

The authors describe their experience in 94 cases of dural fluid collections. The correct diagnosis was made in 94%, which is attributed to (a) including radionuclide angiography and both an immediate and a two- to four-hour delayed scan for every patient undergoing brain studies, (b) a high index of suspicion, and (c) simultaneous interpretation of the scan and the skull film. The false-positive rate was 10%, as shown by cerebral angiography.

Brain Diseases↗

Accuracy of brain scanning in pediatric craniocerebral neoplasms.

A total of 2,563 children were studied by cerebral radionclide angiography, immediate postinjection blood-pool imaging, and delayed 2- to 4-hr. brain scanning. Of 110 new neoplasms of the brain or skull examined, 90% were detected by these means. The scan did not appear to be as accurate in craniopharyngiomas (6/10) and brainstem tumors (5/6). Thirty-nine recurrent tumors not studied previously all produced positive brain scans. Meticulous positioning of the pediatric patient is necessary at all times for accurate results.

Astrocytoma↗

Diagnosis of osteomyelitis in children by combined blood pool and bone imaging.

Differentiation of osteomyelitis from cellulitis or septic arthritis can be difficult. The radiological examination often does not have the characteristic features. Seventy of 71 children with osteomyelitis had focal areas of increased radioactivity at the site of the infection. The addition of "blood pool" images aids in the interpretation of the study as they permit evaluation of the effect of hyperemia. The 13 childrenwith cellulitis had diffuse increase in radioactivity involving both the bones and soft tissues. Bone imaging as the initial screening procedure for osteomyelitis is recommended.

Adolescent↗

Coordinated investigation of cystic astrocytomas by nuclear medicine and neuroradiological techniques.

Astrocytomas are the most common intracranial neoplasm in children. It is necessary to demonstrate preoperatively the location and extent of a possible neoplastic cyst and to differentiate it from the part that is solid. This is achieved through brain scans, computer axial tomography and angiography. Though of considerable help, brain scan and computer axial tomography are insufficient in providing the neurosurgeon with the complete character and geography of the neoplasm necessary for successful surgical treatment. Demonstration of these features can only be elucidated by contrast angiography. Consequently, the coordination of these three techniques permits the precise evaluation of the presence, nature, and operative and postoperative course of cystic astrocytomas.

Astrocytoma↗

Experimental effects of steroids and steroid withdrawal on cerebrospinal fluid absorption.

The authors studied the effects on cerebrospinal fluid (CSF) absorption of chronic administration and acute withdrawal of steroids in dogs. CSF absorption was measured by determining the amount of isotope (indium 111DTPA) recovered over a 4-hour period after injection into the cisterna magna. Resistance to CSF absorption was estimated by determining rates of low of Ringer's lactate infusion into the cisterna magna over a range of pressure gradients between CSF and sagittal sinus. Steroid withdrawal was associated with a marked reduction in CSF absorption and an increase in resistance to CSF flow. Dogs on steroids also showed reduced CSF absorption although the reduction was not statistically significant when compared with controls. The results are discussed in terms of possible mechanisms of action of steroids on CSF absorption, the etiology of the benign intracranial hypertension syndrome and the use of steroids and in the control of intracranial hypertension.

Adrenal Cortex Hormones↗