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Biomedical subjects

K I Marton

Publications and source records attributed to K I Marton.

At least 19 recordsLinked to original sources
PubMed1991

Abnormal corpus callosum: a sensitive and specific indicator of multiple sclerosis.

The authors investigated whether identification of corpus callosal (CC) involvement might increase the specificity of magnetic resonance (MR) imaging in differentiating multiple sclerosis (MS) from other periventricular white matter diseases (PWDs). They prospectively evaluated 42 patients with MS and 127 control patients with other PWDs. Ninety-three percent of the MS patients demonstrated confluent and/or focal lesions involving the callosal-septal interface (CSI). These lesions characteristically involved the inferior aspect of the callosum and radiated from the ventricular surface into the overlying callosum. CSI lesions were optimally demonstrated on sagittal long repetition time (TR)/short echo time (TE) images and frequently (45% of cases) went undetected on axial images. Only 2.4% of the control patients had lesions of the CC. The authors conclude that midsagittal long TR/short TE images are highly sensitive and specific for MS and that callosal involvement in MS is more common than previously reported.

Adult↗
PubMed1990

Using the patient's history to estimate the probability of coronary artery disease: a comparison of primary care and referral practices.

PURPOSE: According to probability theory, the interpretation of new information should depend on the prior probability of disease. We asked if this principle applies to interpreting the history in patients with chest pain. We compared the prevalence of coronary artery disease (CAD) in patients who had similar histories but who came from populations with different disease prevalence. PATIENTS AND METHODS: We studied two high-disease-prevalence populations (patients referred for coronary arteriography) and two low-disease-prevalence populations (patients from primary care practices). We used clinical characteristics of one arteriography population to develop a logistic rule for estimating the probability of coronary artery narrowing. The number of clinical findings determined the logistic score, which was proportional to the prevalence of CAD. RESULTS: The prevalence of CAD was much lower in the primary care population than in the arteriography population, even when patients with similar logistic scores, and thus similar clinical histories, were compared. CONCLUSION: A clinician must take account of the overall prevalence of disease in the clinical setting when using the patient's history to estimate the probability of disease. Failure to observe this caution may lead to errors in test selection and interpretation.

Adult↗
PubMed1989

Medical evaluation of psychiatric patients. I. Results in a state mental health system.

Thorough medical evaluation of 529 patients drawn from eight program categories in California's public mental health system revealed active, important physical disease in 200 patients who had 291 diseases. Fourteen percent of the patients had diseases known to themselves but not to the mental health system, and 12% of the patients had diseases newly detected by the study team. We estimate that of the more than 300,000 patients treated in the California public mental health system in fiscal year 1983 to 1984, 45% had an active, important physical disease. The mental health system had recognized only 47% of study patients' physical diseases, including 32 of 38 diseases causing a mental disorder and 23 of 51 diseases exacerbating a mental disorder. Patients treated in public sector mental health facilities should receive careful medical evaluations.

Adult↗
PubMed1989

The prognostic significance of immunoradiometric CK-MB assay (IRMA) diagnosis of myocardial infarction in patients with low total CK and elevated MB isoenzymes.

Patients with suspected myocardial infarction present a diagnostic problem when they have normal total serum creatine kinase (CK) and an elevated myocardial fraction of this enzyme (CK-MB). We studied 40 patients with normal total serum CK and elevated CK-MB (by standard electrophoretic technique), using an immunoradiometric assay (IRMA) for CK-MB. Diagnosis based on IRMA results of serum samples collected prospectively was compared with diagnosis based on application of strict diagnostic criteria with and clinical diagnosis of the responsible physician(s) by chart review. Diagnostic agreement of all three methods and clinical outcome (mean follow-up 6 months after discharge) were analyzed and compared with two control groups: "rule in" group (17 patients) with elevated total CK, CK-MB, and abnormal electrocardiogram (ECG); and "rule out" group (18 patients) with normal total CK, CK-MB, and ECG. All three diagnostic methods (1) clinical discharge diagnosis, (2) chart review diagnosis by application of strict diagnostic criteria, and (3) IRMA diagnosis, agreed completely for both control groups. Follow-up control group outcomes were in concert with expected outcomes for these groups. Diagnostic differences between methods 1 and 2, and 1 and 3 were statistically significant for the study group. Furthermore, only diagnosis based on the IRMA showed a predictive capability for outcome in this study group when compared with the other methods. Follow-up revealed a similar incidence of cardiac events in the study group (56%) and in the "rule in" control group (60%), but not in the "rule out" group (7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Creatine Kinase↗
PubMed1989

Utility of echocardiography in patients with suspected mitral valve prolapse.

PURPOSE: Echocardiography has become a widely utilized test since its introduction into clinical medicine in the early 1970s. Although it has frequently been performed in patients suspected of having mitral valve prolapse (MVP), its usefulness in this setting has not been systematically studied. To investigate the use and value of echocardiography in patients suspected of having MVP, we conducted a prospective study in which physicians were interviewed before and after ordering echocardiographic testing for patients in whom there was a suspicion of MVP. PATIENTS AND METHODS: The study population included consecutive patients referred to the echocardiography laboratory at Boston University Medical Center because of suspected MVP between January 1 and December 31, 1987. Two standardized telephone interviews were conducted with the physician most responsible for ordering the echocardiogram. The following information was obtained during the first interview, which was always conducted before the echocardiogram was performed: patient demographic and clinical data; the reason for ordering the echocardiogram; the physician's most likely clinical diagnosis; the physician's estimate of the likelihood that the patient had MVP; and the physician's proposed management plans. After the referring physician received the echocardiographic results, a second interview was conducted to determine changes in the most likely clinical diagnosis and management plans. The impact of the echocardiogram on diagnosis and management was evaluated by comparing physician responses before and after reception of echocardiographic results. Receiver operating characteristic (ROC) curves were constructed to assess the physician's skills at distinguishing patients with echocardiographic-documented MVP from those without MVP. RESULTS: A total of 106 echocardiograms were ordered by 45 different physicians. More than 80% of all echocardiograms were ordered to address diagnostic or therapeutic concerns. On echocardiography, 47 (44%) patients were found to have MVP, six (6%) had mitral regurgitation without prolapse, and 53 (50%) had normal results. On the basis of the ROC curve analysis, the physician's ability to discriminate between patients with and without echocardiographic MVP varied significantly by physician specialty and practice setting. The echocardiographic results led to a change in diagnosis in 59 (56%) patients. A change in management occurred in 29 (27%) patients, with 25 of these 29 changes (86%) related to the initiation or discontinuation of antibiotics. CONCLUSIONS: Echocardiography frequently alters diagnostic assessments and leads to therapeutic changes in some patients suspected of having MVP. However, the benefits of such changes have not yet been demonstrated.

Adult↗
PubMed1989

A medical algorithm for detecting physical disease in psychiatric patients.

An algorithm for screening psychiatric patients for physical disease was empirically derived from a comprehensive assessment of 509 patients in California's mental health system. The first 343 patients were used to develop the algorithm, and the remaining 166 were used as a test group. Calculations were made for several versions of the algorithm, and the data were compared with the diagnoses listed in the patients' admission mental health record. The algorithmic procedure was more accurate and more cost-effective than the medical evaluation procedures used by the state mental health system. When applied to the test group, the algorithm detected up to 90 percent of patients who had an active, important physical disease at a cost of $156 per patient. The mental health system had detected 58 percent of test-group patients with a disease at a cost of $230 per patient.

Algorithms↗
PubMed1988

Management of asymptomatic gallstones in the diabetic patient. A decision analysis.

The management of asymptomatic cholelithiasis in patients with diabetes is controversial. We used decision analysis to compare expectant management to prophylactic cholecystectomy in asymptomatic diabetic patients. Relevant probabilities were derived from the literature or expert opinion. Hypothetical cohorts of patients were followed for their lifetimes under each strategy. Expectant management was almost always the superior course. For example, a 30-year-old diabetic man gains an average of 6.1 months of life by choosing expectant management over prophylactic surgery. The superiority of expectant management was invariant to changes in age, sex, and the extent to which major surgical complications affect the future quality of life. Prophylactic cholecystectomy was superior only with extremely high estimates of the likelihood of developing symptomatic disease, the probability of requiring emergency surgery after symptoms develop, and emergency surgical mortality rates. However, no single factor had sufficient impact to alter the optimal decision by itself; the probabilities of several untoward events had to be increased simultaneously to favor prophylactic cholecystectomy. Prophylactic surgery for silent gallstones in diabetic patients does not increase life expectancy or quality of life and may in fact reduce it. This result holds over a wide range of basic assumptions.

Acute Disease↗
PubMed1988

How to image the gallbladder in suspected cholecystitis.

As a result of important advances in medical imaging, the oral cholecystogram is no longer the primary test of gallbladder function and anatomy. Real-time ultrasonography and cholescintigraphy, both highly sensitive and specific tests, are the two major methods for assessing gallbladder pathology. Oral cholecystography, endoscopic retrograde pancreatography, and percutaneous gallbladder puncture serve as supplementary tests. Decisions about which test to use depend on the kind of gallbladder disease that is suspected as well as the estimated likelihood of the disease before the information is obtained from the procedure. Thus, ultrasonography is the test of choice for chronic cholecystitis, with oral cholecystography reserved for situations in which the diagnosis is uncertain after ultrasonography. When acute cholecystitis is suspected, ultrasonography is also the test of choice in most patients, and cholescintigraphy is used to resolve uncertainty.

Cholecystitis↗
PubMed1986

The spinal tap: a new look at an old test.

The spinal tap, or lumbar puncture, has indisputable value; opinions differ, however, on the amount of that value. The procedure has variable utility depending on the clinical indications and the results of tests on the cerebrospinal fluid. Its greatest value is in the evaluation of infectious or malignant meningitis; for most other diseases, it provides additional, but not essential, information. Because of the potential risk of the spinal tap, decisions about when to do the procedure must be made carefully. A probability analysis is provided to elucidate the usefulness of data from cerebrospinal fluid tests.

Bacterial Infections↗
PubMed1985

Modifying test-ordering behavior in the outpatient medical clinic. A controlled trial of two educational interventions.

Education is an effective tool for modifying physician use of the laboratory. We compared two interventions by assigning 56 medical house officers into four groups: control group; feedback group, which received feedback concerning its use of tests; manual group, which received a manual concerning cost-effective laboratory use; and manual plus feedback group, which received both interventions. All intervention groups experienced significant decreases in test use. When we controlled for diagnosis, the manual plus feedback group had the most profound decrease (42%) in laboratory use, followed by the manual group. The feedback and control groups had no change. Attitudes and knowledge did not change. We conclude that one can, via simple techniques, modify house staff use of the outpatient laboratory. The less-expensive intervention was a cost-oriented manual, which may have a "sensitizing" rather than educational effect.

Ambulatory Care↗
PubMed1984

Tutored videotape-instruction in clinical decision-making.

Tutored videotape-instruction (TVI) is a method for providing high quality instruction in topics for which the supply of expert teachers is limited. A small group of students and a tutor can watch a videotaped lecture that can be interrupted for discussion or questions. The tutor facilitates discussion and directs the students to outside reading. The authors in this report describe the use of tutored videotape-instruction in teaching clinical decision-making. Students were randomly assigned to a tutored videotape-instruction group or to a group that heard identical live lectures. The two groups had the same mean score on a final examination on the course material. The group that heard the live lectures rated the quality of instruction higher than the videotape group; however, the ratings were high for both groups. Tutored videotape-instruction provides expertise in a specialized topic and the advantages of instruction in small groups.

Diagnosis↗
PubMed1982

A study of the implicit criteria used in diagnosing chest pain.

Although previous studies have reported the prevalence of coronary artery disease among patients with typical and atypical angina, criteria for the definition of these chest pain syndromes have not been well described. We studied the implicit criteria used by physicians to classify patients with chest pain. Five internists reviewed the histories of 190 subjects admitted to the hospital for elective coronary arteriography and rated each history as indicating either high or low risk of coronary disease. We applied logistic discriminant analysis to these ratings to create a decision rule for the classification of patients with anginal syndromes. The prevalence of confirmed coronary artery disease in subjects classified by the rule as at high risk was 0.83; the prevalence was 0.57 in subjects classified as at low risk. These prevalences are similar to those found for typical and atypical angina in previous large studies. We conclude that this linear model represents the physicians' decisions and provides criteria for defining anginal pain syndromes in certain settings.

Angina Pectoris↗
PubMed1982

Attitudes of patients toward diagnostic tests. The case of the upper gastrointestinal series roentgenogram.

As part of a study of the clinical value of the upper gastrointestinal roentgenogram series (UGI), we assessed patient attitudes toward the UGI and toward tests in general. We surveyed 483 people undergoing 495 outpatient UGIs at three different hospitals. The majority of the patients wanted to have the UGI, were reassured by the test, thought it helped their physicians, would undergo it again for the same problem, and would have requested the test had their physicians not ordered it. Factors that were associated with favorable attitudes toward tests included male sex, older age, having been told the results of the UGI, improvement in symptoms, and lower educational achievement. We conclude that patients place a high value on certain diagnostic tests and that these attitudes may be associated with sociodemographic factors, patient-physician communication and patient symptom status.

Adult↗
PubMed1982

Does continuous care from a physician make a difference?

Continuity of care with a personal health care provider is both an honored and controversial concept. This paper reviews the literature regarding the effect of a continuous relationship with a personal health care provider (longitudinal care) on quality of care using specific selection criteria and methodological standards. Sixteen studies were found of which four provided most of the valid information. Among the studies reviewed, the most common serious methodological problem was inconsistent definitions of continuity. Longitudinal care from a provider has been shown in certain settings to improve patient and staff satisfaction, compliance with medication and with appointments, and patient disclosure of behavioral problems. No ill effects have yet been demonstrated. There is some evidence that having an ongoing provider could reduce the costs of care. From available information, any evolution of the medical care delivery system away from reliance on an ongoing relationship between provider and patient may sacrifice important benefits.

Consumer Behavior↗
PubMed1981

The lumbar puncture. Patterns of use in clinical practice.

The records of 195 patients who had undergone lumbar puncture (LP) before or after the introduction of computerized axial tomography (CT) were reviewed. Twenty percent of the patients had potentially important spinal fluid abnormalities. The LP changed the diagnosis in 10% of the patients and changed therapy in 10% of the patients. It contributed to the patient's care in 32% of the patients prior to the introduction of the CT and in 48% of the patients after the introduction of the CT (p less than 0.05). Introduction of the CT was associated with a 35% decrease in the frequency of the LP (p less than 0.05). We found that fungal and AFB cultures did not appear to be indicated in most patients. We conclude that use of the LP has improved since the introduction of the CT. Further improvement is still possible, however.

Evaluation Studies as Topic↗