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Biomedical subjects

G M Amundson

Publications and source records attributed to G M Amundson.

30 records · Page 2Linked to original sources
PubMed1986

Sonography of adrenal glands in neonates and children: changes in appearance with age.

The sonographic appearance of the normal adrenal gland in children varies with age. In newborns, the cortex is large and hypoechoic, whereas the medulla is relatively small and hyperechoic. With increasing age, the cortex becomes smaller and the medulla relatively larger. The cortex remains hypoechoic and the medulla hyperechoic until age 5-6 months, by which time the gland has become hyperechoic and smaller, with poor or absent sonographic differentiation between cortex and medulla. After 1 year of age, the appearance of the gland is similar to that of the adult gland, with straight or concave borders and a hypoechoic character.

Adolescent↗
PubMed1986

Ultrasonography and the impalpable testis.

The accuracy of inguinal ultrasonography in the pre-operative localization of the maldescended testis was assessed in 51 patients with 57 maldescended testes. Pre-operative sonographic results were compared with the clinical assessment and the operative findings. Testes located in the inguinal canal or at the internal ring, which were occasionally impalpable, were readily demonstrated by sonography. The management of children with an impalpable maldescended testis should include a sonographic examination as the investigative procedure of choice.

Adolescent↗
PubMed1985

Resolution of prepubertal male gynecomastia following removal of a giant pigmented nevus.

A male infant is reported in whom substantial gynecomastia resolved following removal of a giant pigmented nevus. Endocrinological studies were normal. It is postulated that the nevus contributed to the development of gynecomastia. Surgeons should be aware of a possible relationship between these two seemingly unrelated conditions when making evaluation and management decisions.

Facial Neoplasms↗
PubMed1985

A computerized X-ray dose-monitoring system.

An x-ray dose-monitoring system using a small digital computer is described. Initially, and for every 6 months afterward, the system is calibrated using an exposure meter. For each exposure, the computer receives values of x-ray technique and beam geometry from the x-ray generator through a specially designed electronic interface. Then, by means of calibration data, entrance exposure, area exposure product, and integral dose are obtained and printed for each patient examined. The overall accuracy of the system is better than +/- 20%. Operation is semiautomatic, requiring minimum operator intervention. Over 2,000 patients have been monitored with the device. Because the system is computer-based, it offers the opportunity for statistical analysis of the data base created, as the results for each patient are stored on computer disk.

Calibration↗
PubMed1984

Fluoroscopy in children: low-exposure technology.

A fluoroscopic system was modified to achieve a 95-98% reduction in radiation exposure and dosage to patients compared with other systems that reduce fluoroscopic radiation dosage. This reduction was accomplished by custom selection of a high conversion-factor, triplemode image intensifier; custom design of a variable-dose rheostat, allowing maximum operator control of video camera gain; installation of an erbium rare-earth beam filter on the x-ray tube; and addition of a digital noise reducer (recursive filter). A total of 1,577 fluoroscopic examinations has been performed on this system, with excellent results. Contrast resolution was increased, while spatial resolution was maintained. Noise (quantum mottle) has been reduced by the addition of a digital image processor. Advantages of the ultra-low-dose system include: all fluoroscopic work is performed in a smooth, continuous real-time mode; the radiation exposure and dose saving is significantly greater than with pulsed and other proposed low-dose fluoroscopic systems; and the system automatically adapts for the wide variation in patient size routinely encountered in pediatric and adult radiology. The image quality is now such that this system could be used routinely for both adults and children.

Adult↗
PubMed1984

Pediatric digital subtraction angiography.

Experience with intravenous digital subtraction angiography (DSA) in infants and children is limited, although its relative ease of performance, low complication rate, and diagnostic accuracy indicate great potential. We performed 87 DSA examinations (74 patients) and obtained sufficient detail to facilitate diagnosis in most cases. The major problems of patient movement and overlapping vessels can be minimized by judicious use of sedation and strict attention to technique. Exposure of patients to radiation has not been a limiting factor since our system uses low exposure factors (2-38 mR [.51-9.76 mu C/kg]/frame). Our results demonstrate that DSA has wide applicability to many organ systems and is especially useful in intracranial disease and for preoperative evaluation of neoplasms. More specific indications for its use in children must await further correlative studies.

Adolescent↗
PubMed1984

Localized rigidity and narrowing of the antrum: a cause of gastric outlet obstruction in infancy.

In infants with persistent vomiting without bile staining, in whom congenital hypertrophic pyloric stenosis has been excluded, an upper gastrointestinal roentgenogram may show antral obstruction. Of four infants with partial gastric outlet obstruction described by the authors, an antral membrane was demonstrated radiologically in two. Other causes of antral obstruction, such as granulomatous disease, hour-glass deformity of the antrum, cholecystogastrocolic band and antral dysmotility, were considered and excluded as the cause of the vomiting. After medical management failed, gastroscopy revealed a rigid stenotic circumferential area in the antrum in all four infants. An antral membrane was not found. Laparotomy confirmed this finding and a pyloroplasty successfully resolved the symptoms. Localized rigidity and narrowing of the pyloric antrum, masquerading as an antral membrane radiologically, should be considered among the causes of gastric outlet obstruction in infancy. Treatment is determined by the severity of the symptoms. Pyloroplasty is successful when medical management fails.

Body Weight↗
PubMed1982

Prepubertal gynecomastia caused by an adrenal tumor. Diagnostic value of ultrasonography.

Prepubertal gynecomastia is a rare disorder that may be associated with adrenal or testicular tumors. An adrenal tumor causing a mixed feminizing-virilizing syndrome in a 6-year-old boy was identified by ultrasonography, whereas excretory urography failed to show any abnormality. Highly elevated estrone concentrations were found in the plasma, as were more modestly increased levels of estradiol, testosterone, androstenedione, and 11-deoxycortisol. After removal of the tumor, all hormonal concentrations returned to normal prepubertal levels.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Genital tract tuberculosis with peritoneal involvement: MR appearance.

The MR appearance of a case of genital tract tuberculosis is reported. The finding of a large amount of loculated fluid containing septations and debris on ultrasound along with bilateral hydropic fallopian tubes and a thickened omentum on MRI permitted the diagnosis to be suggested preoperatively. With increasing prevalence, such unusual manifestations of tuberculosis will be seen more frequently.

Child↗
PubMedDate not supplied

Failure of a continuous quality improvement intervention to increase the delivery of preventive services. A randomized trial.

CONTEXT: Although there has been enormous interest in continuous quality improvement (CQI) as a measure to improve health care, this enthusiasm is based largely on its apparent success in business rather than formal evaluations in health care. OBJECTIVE: To determine whether a managed care organization can increase delivery of eight clinical preventive services by using CQI. DESIGN: Primary care clinics were randomly assigned to improve delivery of preventive services with CQI (intervention group) or to provide usual care (control group). INTERVENTION: Through leadership support, training, consulting, and networking, each intervention clinic was assisted to use CQI multidisciplinary teams to develop and implement systems for delivery of preventive services. SETTING: 44 primary care clinics in greater Minneapolis-St. Paul. PATIENTS: Patients 19 years of age and older completed surveys at baseline (n = 6830) and at follow-up (n = 6431). Medical chart audits were completed on 4777 patients at baseline and 4546 patients at follow-up. MAIN OUTCOME MEASURES: The proportion of patients who were up-to-date (according to chart audit) and the proportion of patients who were offered a service if not up-to-date (according to patient report) for 8 preventive services. RESULTS: Compared with the control group, based on the proportion of patients who were up-to-date, use of only one preventive service--pneumococcal vaccine--increased significantly in the intervention group (17.2% absolute increase from baseline to follow-up compared with a 0.3% absolute increase in the control group, P = 0.003). Similarly, based on patient report of being offered a service if not up-to-date, delivery of only one preventive service--cholesterol testing--significantly increased in the intervention group compared with the control group (4.6% increase vs. 0.4% absolute decrease in the control group; P = 0.006). CONCLUSION: In this trial, CQI methods did not result in clinically important increases in preventive service delivery rates.

Adult↗
PubMedDate not supplied

The application of i.v. digital subtraction angiography to cranial disease in children.

All intracranial IV digital subtraction angiographic examinations performed over the past 2 years were reviewed retrospectively to ascertain the uses and limitations of this technique for the evaluation of pediatric intracranial disease. Of the various abnormalities studied, this imaging technique was particularly useful in diagnosing venous and dural sinus abnormalities; in screening for suspected large aneurysms, vascular malformations, and major arterial occlusive disease; and in preoperative vascular mapping. IV digital subtraction angiography has selected usefulness in confirming brain death, in evaluating cerebral ischemia, in identifying vascular abnormalities underlying intracranial hemorrhage, and in evaluating vascularity and sinus extension of masses. The IV route for digital subtraction angiography is not useful in diagnosing segmental arterial occlusive or small-vessel disease, nor is it useful in preoperative localization of specific arterial supply to arterial venous malformations, aneurysms, or neoplasms. IV digital subtraction angiography can be performed successfully in children of all ages with minimal patient morbidity. For most patients, the diagnostic information obtained was adequate without the need for standard cerebral arteriography.

Adolescent↗