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Biomedical subjects

M I Boechat

Publications and source records attributed to M I Boechat.

At least 55 records · Page 3Linked to original sources
PubMed1988

Peak trabecular vertebral density: a comparison of adolescent and adult females.

To determine when spinal bone density reaches its peak, the trabecular vertebral density was assessed, via quantitative computed tomography, among females from two age groups: (1) adolescents (aged 14-19 years; N = 24); and (2) young adults (aged 25-35 years; n =24). The adolescent girls had a higher mean trabecular vertebral density (P less than 0.01), suggesting that spinal density reaches its peak around the time of cessation of longitudinal growth and epiphyseal closure.

Adolescent↗
PubMed1988

Osteoporosis in cystic fibrosis.

To determine if osteoporosis is prevalent among patients with cystic fibrosis, we compared the vertebral bone density measured by quantitative computed tomography in 57 such patients (29 male, 28 female, aged 3 to 21 years) with those of an age-, race-, and sex-matched control group of 57 healthy subjects. Patients with cystic fibrosis had significantly lower bone density (10% lower, p less than 0.001) than in controls. The decrease in bone density in patients with cystic fibrosis was unrelated to age. Shwachman clinical evaluation scores (based on case history, pulmonary physical findings, growth, and x-ray findings) correlated positively with age-standardized bone density values (p less than 0.01). Male patients had substantially lower bone density than did female patients (p less than 0.02), but bone density differences related to gender were not significant when effects of disease severity were controlled for. Decreased bone density was more common in patients with poor nutritional status as determined by anthropometric measurements (p less than 0.05). We conclude that osteoporosis is a frequent complication in children with cystic fibrosis regardless of their age and is more prevalent in patients with greater disease severity.

Adolescent↗
PubMed1988

Vertebral bone density in children: effect of puberty.

To determine changes in bone density during growth, trabecular vertebral density and an index of spinal cortical bone were measured with quantitative computed tomography in 101 children. The children were divided by age into three groups: prepubertal, indeterminate, and pubertal. Compared with prepubertal children, pubertal adolescents had significantly higher trabecular bone density and more compact bone in the spine (P less than .001). After controlling for puberty, vertebral bone density failed to correlate significantly with age, sex, weight, height, surface area, and body mass index. The results indicate that bone density increases markedly during puberty.

Adolescent↗
PubMed1988

Primary liver tumors in children: comparison of CT and MR imaging.

A prospective study was performed at two institutions to determine the role of magnetic resonance (MR) imaging in the evaluation of primary pediatric liver tumors. The study compared the usefulness of MR imaging and computed tomography (CT) in providing a correct diagnosis, assessing resectability, and determining tumor recurrence in 23 children with liver tumors. The information obtained with both modalities was correlated with surgical data. The results indicate that the accuracy of MR imaging in helping to differentiate benign from malignant lesions is high and identical to that of CT, but not good enough to obviate surgical diagnosis. While all five hepatocellular carcinomas were correctly diagnosed preoperatively with both modalities, neither CT nor MR imaging could help differentiate these carcinomas from aggressive hepatoblastoma or primary hepatic lymphoma. MR imaging helped correctly predict tumor resectability in all 18 children with malignant hepatic tumors; in one, exact tumor extension was misjudged with CT. Postoperative MR studies suggested tumor recurrence in three children who had unremarkable CT examinations. Second-look surgery showed recurrent tumor in two and fibrosis with chronic inflammation at the surgical margin in the third child.

Adolescent↗
PubMed1988

Effect of sex steroids on peak bone density of growing rabbits.

To determine the effect of sex hormones on bone density (BD) during growth, longitudinal quantitative computed tomography (QCT) measurements were obtained in growing, castrated New Zealand White rabbits following administration of normal saline, testosterone, or estrogen from 6 wk of age until the time of skeletal maturity. Vertebral QCT densities increased during growth, were highest at the time of epiphyseal closure, and were significantly greater (P less than 0.001) in hormone-treated animals. In vivo QCT measurements in 12 vertebraes correlated strongly (r = 0.92) with percentage of calcium per weight assessed in vitro by neutron activation analysis.

Animals↗
PubMed1988

Renal malformations in patients with Turner syndrome: imaging in 141 patients.

Turner syndrome occurs in 1/2,000 to 1/5,000 live female births. The presence of renal malformations was evaluated in 141 patients with Turner syndrome and abnormalities were found in 47 (33%). Prior to 1980, IVP was the radiologic method used for initial screening, and subsequently, ultrasonography has been used as the initial imaging technique. With both methods, major malformations can be detected. Ten patients had a horseshoe kidney, 11 had double collecting systems, four had complete absence of one kidney, three had crossed ectopia, and one had a pelvic kidney. Three patients had ureteropelvic junction obstruction; two of these were asymptomatic and the obstructions were detected only because of the routine imaging. Two patients had ureterovesicular junction obstruction, with one studied as part of a routine evaluation for short stature. Four of these five patients required surgery. Ultrasonography should be used as the initial renal imaging study for all patients at the time the diagnosis of Turner syndrome is made.

Female↗
PubMed1987

Thickened cortical bones in congenital neutropenia.

Congenital neutropenia is an uncommon entity which may be familial and has a wide spectrum of clinical expression. Three sisters with the severe form of the disease, that suffered from recurrent infections which lead to their demise, are described. Review of their radiographs revealed the presence of cortical thickening of the bones. Although several syndromes with different bone abnormalities have been reported associated with neutropenia, the radiographic finding of thickened cortex in children with congenital neutropenia has not been previously described.

Agranulocytosis↗
PubMed1987

Spinal deformities and pseudofractures.

Nine children with spinal deformities had CT examinations after sustaining blunt abdominal trauma. Partial-volume averaging of two lumbar vertebrae suggested a spinal fracture in four children. All four pseudofractures were oriented in a plane perpendicular to the deformity. In two children the spinal deformity could be recognized easily on the scout view. In the other two, the scout view was obtained in a plane different from that of the curvature and concealed the vertebral deformity. Scoliosis resulted in pseudo-fractures running from front to back of the vertebral body, whereas kyphosis resulted in pseudofractures seen in the coronal plane. The pseudofractures lacked associated soft-tissue swelling and had poorly defined, irregular borders that were widely separated by disk material.

Abdominal Injuries↗
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

Pediatric hypertension: an approach to imaging.

Since 1981, we have made diagnoses of secondary hypertension using state of art imaging equipment in 18 pediatric patients. The most valuable tests were ultrasound in identifying renal parenchymal disease, computed body tomography for adrenal tumors and intra-arterial renal angiography for renovascular disorders. Based on our experience, we have formulated an algorithm for the evaluation of the hypertensive pediatric patient. The initial step is careful clinical and laboratory screening to identify those patients that are likely to have essential hypertension and who should not undergo imaging tests. In the cases where there is a possible secondary etiology, renal ultrasound is usually performed first to identify parenchymal disease. If catecholamines are elevated, then abdominal computed tomography is the initial test. If no etiology is identified from these noninvasive studies, then direct intraarterial renal angiography is performed. The authors do not feel that excretory urography, radionuclide renography, intravenous digital subtraction angiography or selective renal vein sampling for renin are useful or practical screening tests for renovascular hypertension.

Adolescent↗
PubMed1986

Magnetic resonance imaging of Wilms tumor.

Magnetic resonance imaging (MRI) in 4 children with Wilms tumor suggests the usefulness of this newer imaging modality in evaluating the organ of origin and defining the extent of Wilms tumor. Coronal T1-weighted images were the most useful pulsing sequence for evaluating these children.

Child, Preschool↗
PubMed1985

Real-time sector ultrasound in the evaluation of suspected abnormalities of diaphragmatic motion.

Real-time sector ultrasonography is the only imaging procedure that can simultaneously evaluate the paradiaphragmatic spaces, the hemidiaphragms themselves, and their motion. Our experience with the use of real-time ultrasonography in the evaluation of 14 cases of suspected abnormalities of diaphragmatic motion and position is presented. With the exception of an equivocal examination in a patient who was completely respirator dependent, all of the sonographic diagnoses were consistent with available clinical and imaging follow-up. Real-time sector ultrasonography should be used as the primary imaging modality for evaluation of suspected abnormalities of diaphragmatic motion and position.

Abnormalities, Multiple↗
PubMed1985

Urinary tract infection in infants and children evaluated by ultrasound.

Fifty-nine pediatric patients with urinary tract infection (UTI) underwent renal ultrasonography, excretory urography, and voiding cystourethrography. The imaging procedures were analyzed retrospectively to determine their relative effectiveness in detecting abnormalities that might predispose the patient to UTI. Voiding cystourethrography provided valuable information, particularly the presence or absence of vesicoureteral reflux, that could not be obtained from the other procedures. Excretory urography was less specific than ultrasonography in the majority of patients, with the exception of those who had renal scarring. The authors recommended ultrasonography as the initial imaging procedure in the evaluation of children with UTI. When the sonogram is normal, excretory urography is not considered necessary, but voiding cystourethrography is thought to be essential. If sonography is abnormal, excretory urography and/or other follow-up studies are indicated.

Adolescent↗