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Biomedical subjects

H C Crow

Publications and source records attributed to H C Crow.

At least 19 recordsLinked to original sources
PubMed2005

The utility of panoramic radiography in temporomandibular joint assessment.

OBJECTIVES: Panoramic radiography was used to determine (1) intrarater and inter-rater reliability in assessing temporomandibular joint (TMJ) condylar morphology; (2) alteration in condylar shape in patients with temporomandibular disorders (TMD) and controls when matched by age, gender, and state of dentition; and (3) prevalence of condylar abnormalities in individuals with and without TMD. METHODS: One hundred panoramic radiographs were randomly selected from a hospital clinic (45 TMD and 55 non-TMD patients). The images were cropped to include only the temporomandibular apparatus and were independently evaluated by three examiners without knowledge of the patient's clinical status. Multiple statistical tests were performed to evaluate the accumulated data. RESULTS: Intrarater reliability demonstrated substantial agreement, while inter-rater reliability was fair. There was no difference in condylar morphology between patient groups, but mild condylar change was prevalent in all age groups, regardless of TMD status. CONCLUSIONS: Morphological condylar abnormalities are present on panoramic images in all adult age ranges, regardless of status of the dentition or presence of TMD. Condylar shape alone is not an indicator of TMD, and minor condylar discrepancies may have no significance in TMD.

Adolescent↗
PubMed1998

Prenatal failure to visualize kidneys: a spectrum of disease.

OBJECTIVES: To better understand the outcomes and management of patients when there is a failure to visualize kidneys on prenatal ultrasound. METHODS: Nine thousand five hundred twelve prenatal ultrasound studies performed on 4900 patients were reviewed retrospectively for the findings of a failure to visualize kidneys. The prenatal ultrasounds, pregnancy outcomes, and postmortem studies were reviewed for each of the 10 patients identified. RESULTS: Nine of 10 patients experienced fetal death in the index pregnancy: 7 had therapeutic abortions, 1 had an intrauterine fetal demise, and 1 gave birth to a stillborn infant. One patient gave birth to a live infant with Bartter's syndrome and grossly normal kidneys, as diagnosed by ultrasound. Developmental renal anomalies were identified in only 4 of 10 cases, and only 2 patients had true bilateral renal agenesis. There was 1 case each of bilateral renal medullary cystic dysplasia and bilateral renal hypoplasia. Three cases had no renal anomalies and included 1 case each of Turner's syndrome, chronic abruption, and a cord accident. In 2 cases, postmortem examinations were not performed because of family wishes. CONCLUSIONS: Prenatal failure to visualize kidneys represents a spectrum of clinical problems not all of which are fatal. Close consultation with an experienced ultrasonographer is essential to provide informed counseling to expectant parents. Pathologic examination should be recommended when there is fetal demise and a suspicion of genitourinary anomalies. Screening of family members of the index patient and genetic counseling may be indicated.

Female↗
PubMed1997

Accuracy of prenatal sonography for detecting circumvallate placenta.

OBJECTIVE: We determined the accuracy of prenatal sonography for detecting placental circumvallation, a placental abnormality associated with increased fetal morbidity and mortality. MATERIALS AND METHODS: We analyzed 62 healthy pregnant (range, 18-36 weeks) patients with focused placental sonography for detection of morphologic abnormality using the published criteria for circumvallate placenta (irregular edge, uplifted margin, or placental sheet or shelf). Placental marginal sonograms were taken at 30 degrees intervals around the entire placental margin. Five experienced sonologists who were unaware of the pathologic findings independently reviewed the placental images and graded the placentas from 1 (definitely normal) to 5 (definitely circumvallate). Receiver operating characteristic (ROC) curves and area under the ROC curve were calculated for each reader. Gross and microscopic pathology was used as the gold standard for all cases. RESULTS: In the 62 patients, sonography revealed 49 normal placentas (79%), 12 partially circumvallate placentas (19%), and one completely circumvallate placenta (2%). ROC curves for the reviewers resulted in values for area under the curve ranging from .39 to .58. The sonologist who achieved the highest value for the area under the curve classified the 13 cases of proven circumvallation as one case of definite circumvallation, four cases as uncertain or equivocal, and eight cases as probably or definitely normal placentas. Of the normal placentas, 35% were graded as probably or definitely circumvallate by at least one sonologist. All sonologists misgraded the case of complete circumvallation as normal. CONCLUSION: Focused placental sonograms interpreted by experienced sonologists fail to detect the placental edge abnormality in most cases of circumvallation. In our study, 17 of 49 normal placentas were diagnosed as probably or definitely circumvallate by one or more observers. Our sonologists' interpretations of sonograms showed that complete circumvallation was difficult to assess. Although our study had a limited number of patients, the accuracy of sonography of the placenta for revealing circumvallation appears to be limited.

Case-Control Studies↗
PubMed1996

Pleural fluid volume estimation: a chest radiograph prediction rule.

RATIONALE AND OBJECTIVES: We devised a prediction rule for estimating pleural effusion volume on the basis of posteroanterior and lateral chest radiographs. METHODS: A prediction rule was devised for estimating pleural effusion volume on the basis of the presence or absence of a meniscus on chest radiographs. The rule was tested and validated using separate data sets obtained from a retrospective review of patients having both a chest radiograph and computed tomography (CT) scan (the gold standard) within 24 hr of each other. The accuracy of the prediction rule and the degree of interobserver agreement between the two independent readers were determined. RESULTS: For the test and validation sets, the weighted accuracies of the prediction rule were 86% and 85%, respectively. The respective weighted interobserver agreements were 97% and 88%. Pleural effusions became visible as a meniscus on the lateral chest radiograph at a volume of approximately 50 ml; at a volume of 200 ml, the meniscus could be identified on the posteroanterior radiograph. At a volume of about 500 ml, the meniscus obscured the hemidiaphragm. CONCLUSION: The volume of a pleural effusion can be estimated from the chest radiograph appearance with a reasonable degree of accuracy.

Humans↗
PubMed1996

Tongue strength and endurance in different aged individuals.

BACKGROUND: It is generally accepted that age-related changes occur in voluntary muscle. Studies of hand grip strength and aging demonstrate a decrease in strength with age; however, there are little data regarding tongue function. The purpose of this study was to determine the relationship of increased age to tongue strength and endurance. METHODS: A pressure transducer, the Iowa Oral Performance Instrument, was used to measure maximal strength and endurance of both the hand and tongue. Ninety-nine healthy volunteers from the oral physiology component of the Baltimore Longitudinal Study of Aging were divided into four age groups, ranging from 21 to 96 years of age. A multivariate analysis of variance was used to determine differences in strength and endurance between age groups and genders. Regression analysis was done to determine the relationship of strength and endurance with age. RESULTS: Gender analysis indicated that both tongue and hand strength were greater in males; however, tongue and hand endurance demonstrated no gender differences. The strength in both the tongue and hand decreased with age. Individuals over the age of 79 years showed statistically decreased tongue strength, and individuals over the age of 59 years showed statistically decreased hand strength. There was no significant change in the tongue and hand endurance with age. CONCLUSIONS: The results of this study suggest that tongue function is gender- and age-dependent and follows the same trends as hand function. Tongue strength is decreased in older individuals and females, while tongue endurance is gender- and age-independent.

Adult↗
PubMed1995

Are gingival and periodontal conditions related to salivary gland flow rates in healthy individuals?

Some have suggested that gingival and periodontal health is related to salivary gland function; however, there are few data to support this hypothesis. The purpose of this study was to determine if correlations existed between major salivary gland flow rates and gingival and periodontal conditions in people of different ages. The results suggest that there is no consistent relationship between major salivary gland flow rates and gingival and periodontal conditions in healthy people.

Adult↗
PubMed1994

Diseases of periodontal tissues in the elderly. Description, epidemiology, aetiology and drug therapy.

Periodontal diseases are among the most prevalent conditions in adults, and afflict many individuals of all ages. They refer to a cluster of inflammatory conditions of the periodontium, the tissues that surround the teeth. Ultimately, periodontal diseases cause the loss of alveolar bone support and may lead to tooth loss. The clinical presentation of periodontal diseases is primarily independent of the age of a person, and successful diagnosis and treatment can be achieved in both young and old individuals. These diseases primarily include gingivitis, periodontitis and oral vesiculobullous diseases of the gingival tissues. Multiple oral, systemic and behavioural factors contribute to the occurrence and progression of these conditions. Appropriate treatment requires accurate diagnosis and the use of oral nonsurgical and surgical techniques, topical and systemic medications and an emphasis on self-applied oral hygiene practices.

Aged↗
PubMed1991

Electronic technology for clinical prosthodontics.

A review of the literature on electrodiagnostic devices indicates that current studies have not substantiated claims regarding the utility of these devices in clinical dentistry. Research design problems, such as inadequate control subjects and use of inappropriate statistical tests, limit the conclusions that can be drawn from the results of these studies. Further research, including measurements of sensitivity and specificity, is needed in order to indicate the diagnostic utility of jaw tracking or electromyography in clinical dentistry.

Diagnosis, Oral↗
PubMed1990

Devices for the diagnosis and treatment of temporomandibular disorders. Part III: Thermography, ultrasound, electrical stimulation, and electromyographic biofeedback.

This last article in the three-part series on devices for the diagnosis and treatment of temporomandibular disorders (TMD) compared the claimed diagnostic usefulness of thermography with the present scientific evidence. In a similar manner, the therapeutic efficacy of ultrasound, electrical stimulation, and electromyographic biofeedback was also reviewed. This evaluation concluded that the application of thermography to the diagnosis of TMD is limited by variations within and among subjects and by intrinsic problems with controls of the test environment. It also concluded that evidence that therapeutic ultrasound alone is useful for the treatment of TMD is lacking, that positive clinical results of electrical stimulation may not be due to specific therapeutic effects, and that it is doubtful that the use of electrical stimulation devices can produce a position of the mandible that has any diagnostic or therapeutic significance. There is evidence, however, that relaxation training, assisted by EMG biofeedback, can reduce daytime muscle activity.

Biofeedback, Psychology↗
PubMed1990

Placental hypoechoic-anechoic areas and infarction: sonographic-pathologic correlation.

High-resolution ultrasound (US) and pathologic analysis were used to define the relationship between placental hypoechoic-anechoic areas, frequently seen in the third trimester, and the clinically significant entity of placental infarction. Placentas were obtained from three groups of patients: those prospectively demonstrating one or more placental hypoechoic-anechoic areas greater than or equal to 1 cm in diameter on third-trimester sonograms (n = 14), those with risk factors for vascular disease (n = 12), and control patients without risk factors (n = 16). Pathologic analysis demonstrated significantly more infarcts in patients with risk factors than in control patients (17 vs three, P = .047). Of a total of 22 infarcts from all three groups, 19 (86%) were isoechoic to viable placenta and therefore not detected with US. The three infarcts identified with US contained hypoechoic or anechoic foci of fibrin or hemorrhage. Of 26 placental hypoechoic-anechoic areas 23 (88%) were decidual septal cysts or intervillous thrombosis without infarction. The authors conclude that nonhemorrhagic placental infarction cannot be identified with ex utero US and, by inference, that prenatal US is probably insensitive for detection of placental infarction.

Female↗
PubMed1989

Triploidy: pregnancy complications and clinical findings in seven cases.

Seven cases of triploidy were encountered by the Prenatal Diagnosis Program at Dartmouth-Hitchcock Medical Center over an 8-year period through associated pregnancy complications. We describe the characteristic findings that facilitate prenatal diagnosis and management. Our experience includes fetuses with major central nervous system abnormalities (spina bifida aperta, holoprosencephaly) and anterior abdominal wall defects, which are detectable with routine prenatal diagnostic screening examinations (ultrasound and AFP). In addition, we stress the importance of recognizing obstetric complications and associated cystic placental changes, which are quite common among triploid conceptuses. Molar changes associated with triploidy have a more benign prognosis than that associated with diploid moles. Such molar changes may relate to the presence of a diploid paternal chromosome complement. The usefulness of cytofluorometric DNA determinations in helping to confirm a clinical suspicion of triploidy is emphasized. These cases are presented in an effort to facilitate prenatal recognition and management of this common cytogenetic condition and prevent unnecessary Caesarean section deliveries.

Adolescent↗
PubMed1988

Fetal choroid plexus cysts: prevalence, clinical significance, and sonographic appearance.

To determine the prevalence, sonographic appearance, and clinical significance of fetal choroid plexus cysts, we analyzed the sonograms and clinical records of 17 fetuses with cysts. Fetal and maternal age, sonographic indication, cyst size and multiplicity, and evolution on serial studies were recorded. Fetal outcome was available in 16 cases by genetic amniocentesis (n = 5) or neonatal clinical records (n = 11). The prevalence of fetal choroid plexus cysts was 0.8% (17/2084) during a 40-month period. All cysts were initially identified on sonograms performed between 14 and 21 weeks. Cysts ranged from 3 to 11 mm in size and were bilateral in four (36%) of 11 cases in which both lateral ventricles were visualized. In nine of 10 cases with serial sonograms 2-21 weeks after the initial study, the cysts were no longer present. One fetus had a small cyst persisting at term. All five cases with genetic amniocentesis had normal chromosomes. The only phenotypic abnormality in the 11 cases with clinical follow-up was a small hemangioma of the chest wall. We conclude that most fetuses with isolated choroid plexus cysts have a normal outcome and that serial sonography for cyst evaluation is not useful in determining fetal prognosis.

Brain Diseases↗
PubMed1985

A cranial nail for fetal shunting.

A small number of human fetal hydrocephalics have been treated by ventriculoamniotic shunts of silastic tubing. The Colorado device appears to be the one most commonly used. The original experimental device tested on a primate model resembled a hollow shingle nail. This was designed by Michedja and Hodgen, contained a spring valve, measured approximately 32 X 4 mm and was placed by hysterotomy. An attractive feature of this design was its fixation by impaction in the skull, preventing displacement by fetal activity, a reported disadvantage with the silastic devices. To our knowledge, no one has used this nail-like design and tailored it to transuterine percutaneous placement in a human case.

Adult↗
PubMed1984

Enhanced visualization of soft tissues in the study of aborted fetuses through the use of xeroradiography.

As part of the diagnostic workup following an episode of fetal loss, it is generally recommended that fetal tissue be submitted for chromosome analysis and that the fetus be photographed and radiographed. Our recent clinical experience has suggested that, in those fetuses where size is compatible, xeroradiography may be superior to standard radiography. Xeroradiography utilizes principles similar to those in film radiology, with low-energy photon beams and relatively long exposure times. The physical characteristics of the beam and imaging system provide optimal soft tissue visualization. We have found this technique to be of use in studying a broad variety of abortuses with abnormalities. Examples of fetal abnormalities in which we have used this technique include acardia, neural tube defects, nuchal cystic hygroma, and arthrogryposis. In fetuses weighing 500-1,000 gm, the exposure settings are 25 MA, 1 second, 40 KVP. For larger fetuses the KVP should be increased by 1 or 2. This technique has not been useful for a complete body view of large fetuses due to the size limitations of the xeroradiographic cassette itself.

Anencephaly↗
PubMed1984

Transillumination lightscanning to diagnose breast cancer: a feasibility study.

Lightscanning is a new technique for breast diagnosis. The breast is illuminated with low-intensity light, and the transmission pattern of relatively narrow bands of red and infrared light is detected, amplified, reconstructed, and displayed in visual wavelengths. With a prototype scanner, 1200 patients referred for xeromammography were examined. All patients had both a lightscan and a xeromammogram obtained on the same day, and the examinations were interpreted blindly and in combination. Thirty-three patients had biopsy-proven cancer. The sensitivity and specificity of the nonblind lightscan and the xeromammogram were comparable. The sensitivity of the blind lightscan was poorer than the other two examinations for tumors smaller than 10 mm and for nonpalpable tumors. The technique of lightscanning is discussed and recommendations for further evaluation are made.

Adult↗