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Biomedical subjects

J W Loop

Publications and source records attributed to J W Loop.

12 recordsLinked to original sources
PubMed1978

Pattern discrimination in matching chest radiographs. Including a role for logistic distribution of observer responses.

Tests were designed to determine how well individuals can differentiate similar chest radiographs. These tests were given to 17 persons (radiologists, x-ray technologists, medical students, and secretaries). Each test contained a number of paired, dissimilar, and/or unique radiographs which were to be distinguished from one another or matched. The results suggest, that a radiologist does not have an innate advantage over untrained observers in pattern recognition. It is not known whether pattern-recognition tests are valuable in evaluating potential radiologists. A receiver operating characteristic curve is also described.

Diagnostic Errors↗
PubMed1978

American College of Radiology Diagnostic Efficacy Studies.

Questions about costs and benefits of radiologic diagnostic methods have lead to the formation of a standing American College of Radiology Committee on Efficacy. In the past several years this committee has defined a hierarchy of efficacies associated with radiographic procedures and developed methods for assigning a numerical value to diagnostic efficacy. A national study of common x-ray examinations in the emergency setting has been conducted. These studies suggest that diagnostic thinking of clinicians was influenced by the results of the x-ray procedures they requested in more than 92% of cases. Medicolegal consideration were a prime concern of the clinician only 6% of the time overall when selecting the most frequent radiologic procedures conducted in hospitals. Considerable uncertainty about clinical diagnoses was typically present at the time radiologic examinations were requested; three-fourths of the time the most important diagnosis under consideration was judged to be less likely after x-ray examination than before. About one-eighth of the time the radiographic information focused attention on a new "most important" diagnosis. The committee plans further studies to include other imaging modalities and practive settings.

Cost-Benefit Analysis↗
PubMed1978

Computed tomography in patients with cerebrovascular disease: impact of a new technology on patient care.

The medical care of 157 patients with suspected cerebrovascular disease was analyzed to assess the impact of the new technology, computed tomography (CT) of the brain, on the care of these patients. A cohort of patients admitted before installation of CT was compared to two cohorts admitted after installation of CT. Length of hospital stay, speed of diagnostic workup, treatment, and discharge plans were not significantly different. Discharge diagnoses were more specific after installation of CT. Lumbar punctures and radionuclide brain scans were used less frequently, but utilization of other diagnostic studies was unchanged. Aggregate charges for diagnostic procedures actually increased in both after-CT groups. In this study, addition of CT to the neurodiagnostic armamentarium resulted in little demonstrable improvement in the care of these patients with cerebrovascular disease but did increase the cost of evaluation. This is unlike the situation for patients with brain tumors, where CT was shown to improve care while not increasing cost. These results may help guide the use of CT by physicians caring for patients with cerebrovascular disease and suggest that health planners not use all patients with cerebrovascular disease in estimating need for CT.

Brain↗
PubMed1977

Jumpers' fractures: patterns of thoracolumbar spine injuries associated with vertical plunges.

Thirty-eight patients who fractured the dorsolumbar spine by vertical plunges are evaluated. The patterns and classification of fractures in cases is presented as well as their salient clinical features. The role of the radiologist in the care of acute spine injuries is highlighted based on the therapeutic implications of proper fracture classification. The role of body section radiography in evaluating patterns of posterior element fractures is suggested.

Adult↗
PubMed1977

Impact of computed tomography on utilization of cerebral angiograms.

In order to assess the effects of computed tomography (CT) of the brain on utilization of cerebral angiography, a retrospective analysis of three cohorts of patients was undertaken. Each cohort consisted of 50 consecutive patients receiving angiography either before a CT scanner was available, after installation of CT, or 1 year after CT. Since availability of CT, a progressive decrease in the proportion of angiograms that are normal has occurred (from 36% to 16%). Patients being evaluated for mass lesions account for the decrease. We conclude that CT is making neurodiagnostic evaluation more efficient and less invasive for patients with suspected mass lesions.

Adolescent↗
PubMed1976

A simple method of femorocerebral catheterization.

A method of catheterizing the cerebral vessels by the femoral route which does not require seating the end hole prior to guide wire introduction has been devised. The orifice of the desired vessel can be localized fluoroscopically via contrast material injections without undue manipulation prior to guide wire introduction.

Catheterization↗
PubMed1976

Radiologic classification of posterior dislocations of the hip: refinements and pitfalls.

Seventeen traumatic hip dislocations seen during a 15-month period were evaluated. In 10 of the 14 cases of posterior hip dislocation, the final Thompson-Epstein classification differed from the initial radiographic classification. Dislocations of the hip often result in radiographically obscure femoral head and acetabular damage. High quality radiographs with oblique and coned-down views are of substantial aid in evaluating the dislocated hip. After closed reduction of a dislocated hip, further views and tomography are helpful but diagnostic pitfalls exist. A persistently widened hip joint, even with negative plain films and tomography, indicates possible intra-osteochondral debris or incompletely reduced femoral head fragments.

Adolescent↗
PubMed1976

Optimal tomographic technique to demonstrate common bile duct stones. An in vitro study.

Six degree and 10 degree circular modes represent the optimal methods available for intravenous cholangiography with tomography within the technical limitations and constraints outlined in this study. The 10 degree mode is superior in the presence of superimposed gas. Ten degree linear tomography is an efficient method for determining the level of the common bile duct but is not the optimal method for obtaining image detail. Thin secretion unidirectional or pleuridirectional modes are occasionally helpful in delineating fine details. The zone of focus is very narrow, permitting very limited sampling within the usual zone of interest. These modes are inefficient in determining the level of the duct and produce less useful image detail than 10 degree circular tomography for ducts of normal, or slightly larger than normal diameters. They are seldom indicated as the primary modality in tomography of the common bile duct.

Gallstones↗
PubMed1975

Bedside pulmonary arteriography.

A new technique of bedside pulmonary arteriography is described, in which small volumes of contrast material are injected manually in order to obtain segmental arteriograms in patients who are too ill to undergo conventional pulmonary angiography. This method is safe and effective and can provide information which is useful in the management of certain critically ill patients.

Angiography↗