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Biomedical subjects

J M Ash

Publications and source records attributed to J M Ash.

16 recordsLinked to original sources
PubMed1992

Detection of silent coronary artery disease in adolescents and young adults with familial hypercholesterolemia by single-photon emission computed tomography thallium-201 scanning.

Familial hypercholesterolemia (FH), a genetic disease characterized by increased levels of total and low-density lipoprotein cholesterol in the blood, results in a markedly increased incidence of atherosclerosis and coronary artery disease in homozygotes and to a lesser extent in heterozygotes. The purpose of this study was to detect the presence of myocardial ischemia, particularly in heterozygotes, with stress single-photon emission computed tomography thallium-201 scanning and to determine if there were any differentiating variables between heterozygotes with normal and abnormal thallium-201 scans. Fifty-four patients (mean age 16 years; range 8 to 24) with FH were analyzed (4 homozygotes and 50 heterozygotes). Eleven heterozygotes and 3 homozygotes had abnormal thallium-201 scans. Family history, lipid profile, age and sex of heterozygotes with FH did not predict the presence of myocardial ischemia. The mean total cholesterol level in heterozygotes with normal thallium-201 scans was 7.68 +/- 2.29 mmol/liter (297 mg/dl), which was not significantly different from that in heterozygotes with abnormal scans (7.63 +/- 1.07 mmol/liter [295 mg/dl]; p = 0.91). The coronary angiography of 1 homozygote who had an abnormal thallium-201 scan demonstrated a 50% stenosis of the left anterior descending artery. Aggressive, repetitive plasma exchange was then instituted. The 11 heterozygotes with abnormal thallium-201 scans underwent more rigorous dietary and drug therapy. It is concluded that myocardial ischemia with stress in heterozygotes with FH can occur at a young age and that thallium-201 scanning should be performed early as a screening test and to guide patient management.

Adolescent↗
PubMed1992

Decrease in gastric emptying time and episodes of regurgitation in children with spastic quadriplegia fed a whey-based formula.

The gastric emptying times associated with three whey-based formulas were significantly shorter than that associated with a casein-based formula in nine gastrostomy-fed patients with spastic quadriplegia (p less than 0.001). Patients fed whey-based formulas had significantly fewer episodes of emesis than when they were fed casein-based formula (p less than 0.001). We conclude that whey-based formulas reduce the frequency of emesis by improving the rate of gastric emptying.

Adolescent↗
PubMed1989

99mtechnetium-dimercapto-succinic acid renal scanning and excretory urography in diagnosis of renal scars in children.

We compared the ability of excretory urography (without tomography) and 99mtechnetium-dimercapto-succinic acid renal scanning to detect renal scars in 32 children with primary vesicoureteral reflux. These children did not have hydronephrosis, renal failure or urinary tract obstruction. In all cases both studies were conducted within a 10-month period. The findings from both modalities were in agreement for 51 of the 64 renal units evaluated (80 per cent). Evaluation of the excretory urogram indicated 6 cases of diffuse and 2 of focal scarring that were not detected by evaluation of the renal scan. The sensitivity of excretory urography to detect renal scars was 84 per cent and the specificity was 83 per cent. The 99mtechnetium-dimercapto-succinic acid renal scan showed 5 cases of focal renal scarring not detected by excretory urography. The sensitivity of the renal scan to detect renal scars was 77 per cent and the specificity was 75 per cent. We conclude that neither study alone could effectively replace the other for the detection of renal scars, and recommend that both be included in the initial evaluation and followup of patients with renal scars.

Adolescent↗
PubMed1987

Radionuclide imaging in histiocytosis X.

Radionuclide imaging (99mTc bone scans, 99mTc S colloid scans, 99mTc brain scans and 67gallium scans) and bone radiographs were done in 54 children with histiocytosis X. The results are discussed, compared with the literature and indications for the different nuclear medicine studies are given.

Adolescent↗
PubMed1987

Noninvasive measurement of blood flow and extraction fraction.

We describe the theory of a technique for the noninvasive measurement of organ blood flow which is based on the principle of fractionation of cardiac output and is applicable with any recirculating gamma emitting tracer. The technique effectively determines the count rate that would be recorded over the organ if the tracer behaved like radiolabelled microspheres and was completely trapped in the organ's vascular bed on first pass. After correction for organ depth, the estimated first pass activity plateau, expressed as a fraction of the injected dose, is equal to the organ's fraction of the cardiac output (CO). By extending the theory, organ extraction fraction of extractable tracers or mean transit time of nonextractable tracers can be measured. Renal blood flow (RBF) to the normal left kidney in 18 subjects without evidence of renal disease was estimated by the technique to be 10.4% CO (S.D. 1.2), for the right kidney 9.0% CO(S.D. 1.1), and for both, 19.4% CO (S.D. 1.5). In a separate series of eight patients, RBF values were highly reproducible when obtained on successive days (standard deviation of change: 0.67% CO for the left kidney, 0.63% CO for the right and 0.78% CO for both). The extraction fraction of DTPA (filtration fraction) was 8.5% (1.7) in the left kidney and 9.7% (2.1) in the right kidney. This parameter was less reproducible than RBF, with standard deviations of the changes equal to 1.17% for the left kidney and 1.31% for the right. Stable, well-functioning, renal allografts in children had a mean blood flow of 20.6% CO (S.D. 3.7). Transplant blood flow in eight patients with rejection was less than 5.2% CO. In patients without splenomegaly, splenic blood flow, splenic extraction fraction of sulphur colloid and splenic red cell mean transit time were 4.3% CO (S.D. 0.9), 41% (S.D. 13.8), and 36.9 s (S.D. 4.6), respectively.

Blood Circulation↗
PubMed1979

Radionuclide skeletal survey in neuroblastoma.

Of 63 99mTc-phosphate bone images in 49 patients with neuroblastoma, 41 were abnormal, 17 showed tracer uptake within the primary tumor, 29 showed evidence of skeletal metastatic disease, and 17 demonstrated renal/urinary tract involvement. The metastases were asymmetric in 24 patients and symmetrical in 9, in whom they involved the metaphyses and epiphyses of the long bones. Except for one patient with multiple "cold" areas, all metastases were seen as focal hyperactive regions. Eleven of 42 skeletal radiographic surveys were abnormal. The radionuclide study appears to be more accurate than skeletal radiography in estimating bone involvement in neuroblastoma. Primary tumor concentration of the tracer is almost pathognomonic of neural crest neoplasms in childhood.

Abdominal Neoplasms↗
PubMed1979

Craniosynostosis: correlation of bone scans, radiographs, and surgical findings.

Skull scintigraphy was performed in 68 children with suspected craniosynostosis after injection of technetium-99m methylene diphosphonate. The scans demonstrated four patterns of sutural activity: normal, absent, increased, and wide. When correlated with surgical findings, "absent" indicated fused sutures, "increased" indicated fusing hyperactive sutures or sutures reacting to fusion elsewhere, and "wide" indicated splite sutures. Upon correlation with the radiographs, it was found that when the radiograph was normal, the scan contributed little; when the radiograph was abnormal or equivocal, the scan was often of great assistance in confirming fused sutures and detecting other abnormal sutures.

Child, Preschool↗
PubMed1979

Radiopharmaceutical bone scanning in pediatric neurosurgery.

Radionuclide bone scanning is an extremely sensitive, safe and widely applicable investigative aid. In most circumstances it cannot be employed to the exclusion of plain radiography as the two procedures--one dynamic and the other static--complement each other. In children, bone imaging demonstrates physiologic characteristics of bone growth and early suture closure, delineates obscure tumors and infection, recent or old trauma not always visible on orthodox radiography and may solve the diagnostic dilemma of a child with heretofore undiagnosed head, neck or back pain.

Back Pain↗
PubMed1978

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↗
PubMed1977

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↗
PubMed1977

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↗
PubMed1976

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↗