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Biomedical subjects

H E Rockette

Publications and source records attributed to H E Rockette.

At least 55 records · Page 3Linked to original sources
PubMed1990

Effect of two rating formats in multi-disease ROC study of chest images.

ROC methodology has been expanded in recent years to include multi-disease experiments. To accommodate these changes, different rating formats, general or disease specific, can be used. No experimental data are available concerning the possible effects of the rating format on the results of these studies. We performed a multi-observer, multi-disease study in which 196 chest images were rated using a format where each disease was evaluated individually and one in which the cases were evaluated without scoring a specific disease. The results indicate that for our data set, the overall assessment of accuracy was not significantly affected by the study format used. Thus, in spite of the difficulties in selecting appropriate controls and the necessity of reassessing sample size considerations, the disease-specific format appears to produce an assessment of accuracy equivalent to that produced by the general format. This equivalence permits the use of the disease-specific approach since it more closely simulates the readers' true environment and is more appropriate for comparing imaging systems that may have a relative accuracy that is disease specific.

Diagnosis, Differential↗
PubMed1990

Effect of observer instruction on ROC study of chest images.

Receiver-operating characteristic (ROC) analysis has been used in many medical imaging applications during the past decade. In order to ensure that reader-confidence ratings are analyzable (well distributed to meet convergence requirements of curve-fitting algorithms) and meaningful (limit extrapolation of the data), many investigators train readers specifically for this purpose. No experimental data are available concerning the possible effects of such training on the results of ROC studies. We performed a multi-observer, multi-disease study in which 300 chest images were rated by four radiologists before and after they were trained to provide well-distributed confidence ratings. The results indicate that for our data set, reader and disease-specific accuracy was not significantly affected by the training process for interstitial disease and pneumothoraces. However, the accuracy of two readers was significantly affected for the detection of nodules (P less than 0.05), and the overall accuracy of one reader was significantly affected for the classification of normal versus abnormal images (P less than 0.01). Thus, in spite of the difficulties associated with the performance of ROC studies in a free-reading environment, one should carefully consider the possible effects of any intervention on the results prior to conducting ROC studies.

Humans↗
PubMed1990

Practical issues of experimental ROC analysis. Selection of controls.

Receiver operating characteristics (ROC) analysis has been used in many medical imaging applications during the past decade. With the recent expansion of the ROC methodology to multi-disease studies, several reports have begun to address both the theoretical and experimental design issues associated with such studies. While the appropriate selection, classification, and verification of actually positive cases is carefully addressed in the literature, similar considerations are rarely given to the selection of actually negative controls for these studies. In this paper, theoretical considerations and experimental data are provided to demonstrate the significance of this very issue.

Case-Control Studies↗
PubMed1990

Nonparametric estimation of degenerate ROC data sets used for comparison of imaging systems.

Maximum likelihood estimation, assuming a binormal model, has been used extensively to estimate the area under receiver operating characteristic (ROC) curves and thus provide an index of diagnostic accuracy for the comparison of two imaging systems. However, in some instances, a degenerate data set results in a fitted ROC curve of inappropriate shape. In those instances, a nonparametric Wilcoxon statistic may be used to compare the areas under two ROC curves. Simulation of this approach indicates that the procedure has relatively high statistical power and its use in specific degenerate data sets shows its applications potential.

Data Interpretation, Statistical↗
PubMed1990

The effect of image processing on chest radiograph interpretations in a PACS environment.

The question of whether image processing affects a radiologist's diagnostic performance is becoming more important as the digital modalities proliferate. In the multi-observer study reported, the performance of radiologists who interpret a series of posteroanterior digitized chest images displayed on a high-resolution workstation, with and without a set of image processing options, is determined. These include brightness, contrast, reverse look-up tables (black-bone), and two edge enhancement options. Three hundred images were evaluated twice (once in each mode) by each of seven board-certified radiologists, who recorded their confidence ratings for the presence or absence of one or more of the following abnormalities: interstitial disease, nodule, and pneumothorax. The original, unprocessed digital image was available for reference for those sessions in which the processing options were available. With the exception of one reader, receiver operating characteristic (ROC) analysis showed no statistically significant difference between the two modes (with and without processing) for the detection of any of the different abnormalities by individual readers. Likewise, the group as a whole showed no significant difference (P less than .05) for detection of any of the three abnormalities between the two reading modes.

Hospital Information Systems↗
PubMed1990

Receiver operating characteristic analysis of chest image interpretation with conventional, laser-printed, and high-resolution workstation images.

The differences among radiologists in interpreting conventional and digitized images obtained with different radiologic procedures is an important research issue in these times of implementation and growth of the digital modalities. The authors performed a multiobserver study to determine the performance of radiologists reading posteroanterior conventional radiographs, digitized radiographs laser printed onto film, and images displayed on a high-resolution workstation (video monitor). A total of 300 images were evaluated by seven radiologists who recorded their ordinal confidence rating of the presence or absence of one or more of the following abnormalities: interstitial disease, nodule, and pneumothorax. Receiver operating characteristic analysis showed statistically significant differences for the detection of different abnormalities by individual readers. The group as a whole showed a significant reduction in observer performance for the detection of interstitial disease and pneumothorax when the laser-printed radiographs or the workstation was used rather than conventional radiographs.

Computer Systems↗
PubMed1990

Does knowledge of the clinical history affect the accuracy of chest radiograph interpretation?

To examine the effect that a concise, objective, and potentially computer-extractable history would have on diagnostic accuracy in the interpretation of chest radiographs, we designed and tested a computerized patient-history form that could be integrated realistically into the clinical environment. We performed a series of studies in which 247 posteroanterior normal (79) and abnormal (168) chest radiographs were interpreted by four board-certified radiologists, both with and without accompanying clinical histories. The radiologists recorded their confidence rating of the presence or absence of one or more of the following abnormalities: interstitial disease, nodule, and pneumothorax. Analysis of receiver operating characteristics showed that, with the exception of interpretation of one abnormality by one radiologist, there were no statistically significant differences (p less than .05) between cases interpreted with and without the history form for any of the radiologists. The results of our study suggest that knowledge of clinical history does not affect the accuracy of chest radiograph interpretations for the detection of interstitial disease, nodules, and pneumothoraces. These results may not be applicable to other clinical situations.

Humans↗
PubMed1989

Myringotomy with and without tympanostomy tubes for chronic otitis media with effusion.

We studied 109 children with otitis media with effusion of 2 months' duration or longer that was unresponsive to medical management. Eighty-six subjects who had neither "significant" hearing loss nor defined symptoms were randomly assigned to receive myringotomy, myringotomy with tympanostomy tube insertion, or no surgery, and 23 subjects with significant hearing loss, defined symptoms, or both were randomly assigned to receive either myringotomy or myringotomy with tube insertion. Myringotomy with tube insertion provided more disease-free time and better hearing than either myringotomy alone or no surgery; however, some subjects who underwent myringotomy with tube insertion developed otorrhea or persistent perforation of the tympanic membrane. Myringotomy offered no advantage over no surgery regarding percent of time with middle-ear effusion, number of acute otitis media episodes, and number of subsequent surgical procedures. These results may not properly be extrapolated to less severely affected children.

Acoustic Impedance Tests↗
PubMed1988

A comparative study of amoxicillin-clavulanate and amoxicillin. Treatment of otitis media with effusion.

A double-blind randomized clinical trial was conducted at two sites comparing amoxicillin-clavulanate potassium (Augmentin) and amoxicillin trihydrate for the treatment of otitis media with effusion ("secretory otitis media"). One hundred eight subjects were randomly assigned to receive a ten-day course of either drug regimen. Clinical response was assessed at ten days and four weeks after entry. For those without middle ear effusion at four weeks, recurrence rates were measured at 8, 12, and 16 weeks after entry. At ten days following entry, 29 (51.8%) of 56 subjects in the amoxicillin-clavulanate-treated group were effusion free compared with 16 (32.0%) of 50 subjects in the amoxicillin-treated group (P = .06). At four weeks following entry, 26 (50.0%) of 50 subjects in the amoxicillin-clavulanate-treated group were effusion free compared with 23 (51.1%) of 45 subjects in the group given amoxicillin. By the 16-week visit, eight (36.4%) of 22 subjects in the amoxicillin-clavulanate-treated group who were effusion free at four weeks had recurrence of effusion, compared with 12 (63.2%) of 19 subjects in the amoxicillin-treated group. This study suggests that there was a favorable clinical response immediately following treatment in the amoxicillin-clavulanate--treated subjects as compared with those treated with amoxicillin, but this benefit was not sustained at the four-week end point.

Adolescent↗
PubMed1988

Ovarian follicular maturation in women. II. Reversal of estrogen inhibited ovarian folliculogenesis by human gonadotropin.

The current study was undertaken to investigate the role of follicle-stimulating hormone (FSH) in reversing estrogen-induced follicular atresia. Normal menstruating women received ethinyl estradiol (EE2) 50 micrograms/day orally from days 2 to 7 after the onset of menses. Concomitant intramuscular injections of 1.0 ml of saline were administered to group 1, 75 IU of FSH and luteinizing hormone (LH) to group 2, and 150 IU units of FSH and LH to group 3. Daily blood samples were obtained throughout the investigative cycle for FSH, LH, 17 beta-E2, and progesterone. The women in group 1 had evidence of follicular atresia and a significant reduction in serum FSH and LH when compared to group 3 (P less than 0.002 and less than 0.001 respectively). Ovarian follicular development was maintained in groups 2 and 3, based on ultrasound evidence and the interval from menses to midcycle LH surge. These data indicate that the exogenous administration of FSH and LH results in maintenance of ovarian follicular development in women treated with exogenous estrogen.

Body Temperature↗
PubMed1987

An attitudinal assessment of faculty practice plans.

An awareness of potential conflict between medical schools and private practice prompted an attitudinal assessment of faculty practice plans (FPPs). A representative sample of eight medical school FPPs in seven different communities was selected for study. For each FPP, a sample of health care leaders, stratified at different levels of administrative responsibility, was selected from academic medical centers and from community settings. Topics for FPP assessment were chosen for their relevance to physician and lay administrators involved with academic and community practice. Questions were answered on a yes-no basis and were graded by intensity of response. Although only two of the questions revealed statistical disparity on a simple yes-no basis, the intensity of response differed significantly in eight of the 14 questions asked. This study gives consideration to the strategic implications of FPPs for universities, medical schools, and organized medicine.

Administrative Personnel↗
PubMed1987

Efficacy of amoxicillin with and without decongestant-antihistamine for otitis media with effusion in children. Results of a double-blind, randomized trial.

In a randomized, double-blind, placebo-controlled trial involving 518 infants and children who had otitis media with effusion ("secretory" otitis media), we evaluated the efficacy of a two-week course of amoxicillin (40 mg per kilogram of body weight per day) with and without a four-week course of an oral decongestant-antihistamine combination. Among the 474 subjects who were evaluated at the four-week end point, the rate of resolution of middle-ear effusion was twice as high in those treated with amoxicillin, either with or without the decongestant-antihistamine, as in those who received placebo (P less than 0.001), but 69.8 percent of the amoxicillin-treated subjects still had effusion. Among both the amoxicillin-treated subjects and the placebo-treated subjects, resolution was more likely in those with initially unilateral effusion, in those who had had effusion for eight weeks or less, and in those without an upper respiratory tract infection at the four-week end point. Side effects were reported more often in subjects who received decongestant-antihistamine than in those who did not. Among the subjects without effusion at the four-week end point, recurrent effusion developed in approximately half those in both the amoxicillin and placebo groups during the subsequent three months. We conclude that in infants and children with otitis media with effusion, amoxicillin treatment increases to some extent the likelihood of resolution.

Amoxicillin↗
PubMed1987

Amoxicillin-clavulanate potassium compared with cefaclor for acute otitis media in infants and children.

One hundred thirty-three infants and children with documented acute otitis media (OM) were randomized to receive the oral suspension of either amoxicillin-clavulanate potassium or cefaclor. Beta-lactamase-producing bacteria were found in 10.9 and 14.5% of subjects treated with amoxicillin-clavulanate potassium and cefaclor, respectively. Subjects were reexamined at 5, 10, 30, 60 and 90 days after the initiation of therapy and whenever signs/symptoms of acute otitis media recurred. All but two children had resolution of otalgia/otorrhea during the initial treatment period. The drug groups were not significantly different in the percentage of evaluable subjects with otitis media with effusion at each scheduled follow-up visit. Recurrence of acute OM/otorrhea [corrected] developed in a similar percentage of subjects in both treatment categories. Both subjects with and those without middle ear effusion at 10 days had approximately a 50% recurrence rate of subsequent middle ear disease. Adverse side effects/complaints, which occurred in significantly more children treated with amoxicillin-clavulanate potassium, were generally mild and primarily gastrointestinal.

Acute Disease↗
PubMed1986

Prediction of ovulation with basal body temperature.

Basal body temperature (BBT) is used extensively to monitor ovulation in the treatment of infertility. There are well-defined methods of interpreting the BBT graph retrospectively that identify a presumptive day of ovulation. The prediction of ovulation through utilization of the BBT graph (strictly concurrent interpretation) is adversely influenced by temperature fluctuation and cycle length variability. The BBT graph can be very useful when its interpretation is well defined and its limitations understood.

Body Temperature↗