Biomedical subjects
Publications and source records attributed to M Miskin.
A guide presented in this article provides the sonographer with a list of fetal malformations that have been described in association with specific drugs or chemicals and that can be visualized by current ultrasonographic techniques.
Twenty-four cases of fetal cystic hygroma colli were diagnosed by ultrasound. In two patients, the diagnosis was not confirmed at autopsy. Ten of these were cases of Turner's syndrome, one was a case of Turner's mosaicism, three had other aneuploidies, four had normal chromosomes, and six had a failed chromosome culture. The diagnosis, management, and future counseling of these patients are discussed.
Death in utero of one member of a monozygotic twin pair has been associated with vascular disruptive phenomena in the surviving twin. It has been hypothesized that this event initiates clot formation in the surviving twin with consequent necrosis of tissues distal to the occluded vessels. This case report describes onset in utero of multicystic encephalomalacia and microcephaly in a surviving twin whose brain appeared normal on ultrasound scanning before death of the cotwin at 21 weeks' gestation. The case provides further support for the hypothesized pathogenetic sequence and illustrates the importance of reviewing all prenatal ultrasound scans in infants with congenital microcephaly.
Clinical assessment of a patient with a focal or diffuse thyroid tumor is but the first step in diagnostic evaluation. The diagnostic imaging process augments information obtained by the inspecting eye and the palpating hand; it allows the qualification (for example, cystic v solid) and the quantification (for example, size, extension, and assessment of physiologic function) of the thyroid tumor mass. This diagnostic input allows the establishment of a more realistic provisional diagnosis and directs a rational treatment approach to the patient. This presentation reviews the major imaging modalities available for thyroid tumor evaluation: diagnostic ultrasound, radionuclide scans, and conventional radiology and computed tomography. The applications of these various modalities and their critical potentials and limitations are placed in a contemporary clinical setting. It is hoped that an increasing familiarity with these imaging modalities will give better direction to the specialist in otolaryngology--head and neck surgery and greater surgical benefit to his or her patients.
Based on data from 5 cases of fetal cystic hygroma (4 cases of Turner's Syndrome and one case of Trisomy 18) and one case of Down's Syndrome with severe subcutaneous oedema, it is concluded that amniotic fluid alpha-fetoprotein (AFP) is normal or only slightly elevated in such cases whereas AFP in fluid from the cystic structures is very high. Reported high values of 'amniotic fluid' AFP are therefore likely to have been obtained from fluids accidentally drawn from the cystic structures. Fluids from the two sources cannot be distinguished from each other visually. In support of this theory is that the maternal serum AFP was found to be normal in all cases where investigated. In the diagnosis of cystic hygromata detailed ultrasound scanning will reveal the correct diagnosis.
Amniotic fluid alpha-fetoprotein (AFP) assays and detailed ultrasound examinations were performed in 376 prenatal patients at risk for a neural tube defect (high-risk group). In addition, 2436 patients who underwent amniocentesis for other indications underwent preamniocentesis ultrasound screening and amniotic fluid AFP assays (low-risk group). There were 10 neural tube defects in the high-risk group (7 open and 3 closed) and 3 in the low-risk group (all open). Two of the 3 closed defects were detected prenatally. The predictive value of an elevated AFP level for an abnormal fetus was much higher in the high-risk (6 of 6, 100%) than in the low-risk group (1 of 6, 17%). When both ultrasound and AFP assay results were normal, the chance of a normal outcome was very high in both the high- and low-risk groups (99.7 and 100%, respectively). It was of particular interest that in the low-risk group, the likelihood of an abnormal outcome in women with elevated AFP and a normal ultrasonogram was low (0 of 5).
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Placental localization by diagnostic ultrasound was performed at 16 to 18 weeks' gestation in 1,098 patients prior to amniocentesis for genetic indications. Placenta previa was diagnosed in 58 patients, 47 of whom went on to delivery uncomplicated by placenta previa. There were five patients with placenta previa at delivery, four of whom had third-trimester bleeding. One patient was diagnosed as having a normal placental implantation at midtrimester but placenta previa was demonstrated at delivery. The incidence of placenta previa at 16 to 18 weeks' was 5.3% and fell to 0.58% at delivery, indicating a 90% conversion rate. Thus the vast majority of cases of asymptomatic placenta previa remain so and convert before delivery. These patients should be observed with serial ultrasound at 6 to 8 week intervals until delivery or unequivocal conversion. No restriction in activity seems indicated unless the placenta previa persists beyond 30 weeks or becomes clinically manifest.
An unusual form of crossed renal ectopia is presented. Both kidneys are at the same level on the same side with fusion throughout their entire lengths.
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Ultrasonography of the thyroid gland permits differentiation between cystic, solid, and mixed lesions, allowing conservative management of cystic lesions, which constitute 20% of hypofunctioning nodules. The combination of ultrasonography and fine needle aspiration cytology appears to be a great advance in the preoperative diagnosis of nontoxic goiter and permits individualized treatment in as precise a manner as is possible at present.
The ultrasonic appearance of the normal and abnormal fetal spine before 20 weeks' gestation was reviewed in 121 pregnances. A model was constructed to establish the mechanism of production in the various configurations seen. The relative roles of ultrasonography, alpha fetoprotein assay, and fetoscopy in the diagnosis of spina bifida are discussed.
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