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Biomedical subjects

P G Herman

Publications and source records attributed to P G Herman.

82 records · Page 5Linked to original sources
PubMedDate not supplied

The composition of the radiologic report.

In order to understand and evaluate fully the composition of the radiologic report, an experiment was performed in which eight readers each read the same 100 chest radiographs. The reports were dissected into individual statements, each of which was analyzed for accuracy, statement type (descriptive or etiologic), confidence, and specificity. In addition, each report was evaluated for stylistic factors of succinctness, orderliness, and the use of supplemental comments. Detailed analysis showed the radiologic report to be a series of largely descriptive statements in which confidence level, specificity, and orderliness were associated with the presence of errors in film interpretation. These factors can serve as important markers for identifying error-laden films. The use of specific, etiologic diagnoses in these film readings was limited. The composition of the report was not related to the length of radiologic training beyond the first year of residency. The implications of these findings concerning report composition in light of present day radiologic practice and new, automated radiologic reporting systems were discussed.

Diagnostic Errors↗
PubMedDate not supplied

Improving diagnostic accuracy: a comparison of interactive and Delphi consultations.

Consultation among physicians on difficult diagnostic problems is commonly used to improve the accuracy of medical decisions. Such consultation is most often informal and interactive. Nevertheless, behavioral studies suggest that non-interactive techniques may be more effective problem solving methods. Of these the Delphi approach, involving pooling and feedback of anonymously contributed information, has generated particular interest. To assess the relative effectiveness of independent decision making, interactive group consultation, and Delphi techniques in a clinical setting we compared the diagnostic accuracy of 17 radiologists interpreting radiologic examinations in these settings. Interactive consultation improved performance by 69% compared to radiologists interpreting the studies individually. In addition, two Delphi strategies each produced an additional 20% mean improvement in accuracy over interactive consultation. Whereas interactive consultation improved the accuracy of the best individual readers by only 6%, a Delphi model improved their performance by 25%. Thus, Delphi was an effective, easily applied method of clinical consultation whose usefulness in other clinical setting should be evaluated.

Decision Making↗
PubMedDate not supplied

The renal collecting system after medullary damage.

The micromorphology of the renal collecting system after unilateral papillectomy in rabbits was investigated. Two weeks to six months after papillectomy, tubular micropuncture studies were performed. Cleared specimens were studied by light microscopy and microradiography. Histologic and physiologic correlations were made. At two to four weeks, the papillectomized kidneys were smaller and had smooth, mottled surfaces. At one to six months, there was cortical scarring with decreased concentrating ability. Ductal micropuncture revealed dilated collecting tubules and ducts which were obstructed at the papillectomy site. It is concluded that obstructed collecting ducts may be responsible for the cortical atrophy and are the primary cause of renal cortical damage after papillectomy in our model.

Animals↗
PubMedDate not supplied

Radiographic interpretation with and without search: visual search aids the recognition of chest pathology.

Radiologists could distinguish between the normal and abnormal radiographic features in a specific test set much better when searching chest radiographs for any abnormal findings than when explicitly evaluating each individual test feature without searching the films. Because the radiologists' ability to separate the subtle test abnormalities from normal variations was severely reduced by directing attention to these particular radiographic features, the recognition of abnormal findings may have been augmented by perceptual mechanisms that functioned only during the process of visual search. These could be visual mechanisms, developed through experience in scanning familiar examinations, that detect "unusual" pattern configurations and automatically draw the radiologist's attention to features that are likely to represent pathology.

False Positive Reactions↗
PubMedDate not supplied

Imaging of lymphoid structures with indium-111-labeled lymphocytes.

The ability of indium-111 (111In)-oxine-labeled syngeneic lymphocytes to migrate normally and their suitability for imaging both normal lymphoid structures and those with metastatic disease were assessed. Sixty-two ACI rats were studied, 34 of which received injections in the left foot pad with 1 X 10(6) syngeneic H-4-II-E hepatoma cells nine to 44 days before imaging. Most animals were bearing palpable tumors when imaged. In 53 experiments, 1-6 X 10(8) 111In-oxine-labeled lymphocytes with a labeling concentration of 5-80 microCi/10(8) cells were injected intravenously. Gamma camera images were obtained 22 hours later. After the last image, the animals were killed. The lymph nodes, liver, spleen, lungs, and left femur were dissected, and the recovered radioactivity was determined in a gamma well counter. Lymph nodes could be partially or completely visualized in 70% of the animals (15 tumor-bearing and 16 normal out of 44 technically satisfactory experiments). Large metastatic nodes were seen clearly. Lymphocytes labeled with 111In-oxine exhibited a normal migration from blood to lymph nodes.

Animals↗
PubMedDate not supplied

The value of searching films without specific preconceptions.

The detection of simulated pulmonary nodules was measured in three different situations that required: (1) reports of all significant chest findings (Free Search), (2) only reports of possible nodules (Nodule Search), or (3) evaluation of particular film locations as nodules (Specified Location). ROC curves from these conditions compared how accurately readers could distinguish between the nodule and normal "test locations," and between the films that did and did not contain nodules. In replication of previous results for heterogeneous chest findings, detection accuracy was superior when readers had to search the films. Each reader's distinctions between the nodule and normal test locations became considerably less accurate when these locations were prespecified for explicit evaluation. When asked to search only for pulmonary nodules, most readers substantially increased their false reports of nodules at each level of confidence, with little improvement in their (already high) true-detection rates. Searching for nodules increased both the true-detection and false-detection rates for two readers, who simply appeared to relax a strong bias against reporting nodules in the initial Free-Search situation.

False Positive Reactions↗
PubMedDate not supplied

Comparison of fixed and adjustable window width and level settings in the CT evaluation of diffuse lung disease.

OBJECTIVE: The purpose of this investigation was to assess the utility of allowing free adjustment of window width and level in comparison with the use of a fixed lung window in the CT evaluation of diffuse lung disease. MATERIALS AND METHODS: Six radiologists each judged 36 cases (28 diffuse lung disease and 8 normal) using a standardized form. In half of the sessions, images were viewed in a fixed lung window (level = -500 HU; width = 2,000 HU). In the other sessions, the observer was able to adjust the window and level freely while viewing the images. Each case was seen twice in separate sessions: once in a fixed lung window and once with window width and level adjusted by the reader. A variety of diagnostic features were evaluated using a 5 point scale. These included visibility of fine lung structures, abnormalities of the lung parenchyma, and overall evaluation of the lung. RESULTS: The visibility of lung structures was not improved with adjustable window settings. Receiver operating characteristic (ROC) analysis showed fixed windows to be superior to adjustable windows for overall evaluation of the cases [fixed A(z) = 0.90, adjustable A(z) = 0.84, p < 0.05, jackknife method]. Time to rate each case was increased by 15% with window width and level adjustment. CONCLUSION: Free adjustment of window width and level produced no improvement in reader performance over that achieved with fixed window width and level.

Humans↗
PubMedDate not supplied

Maximizing the efficacy of chest radiography in the ICU.

In a prospective survey, we found that chest radiographs taken at the bedside in the intensive care unit had an appreciable impact on patient management, demonstrating new findings or changes 65% of the time. Monitoring devices can best be checked radiographically, and changes in cardiopulmonary status may be difficult to assess or confirm by other means. Consistent radiographic technique, availability of films to referring clinicians, and rapid reporting by radiologists serve to maximize the efficacy of bedside radiography.

Boston↗
PubMedDate not supplied

The radiologic assessment of vessel wall thickness.

A method allowing accurate and repeated measurements of vessel wall thickness has been developed. It consists of permanent opacification of the outer wall with tantalum in conjunction with magnification angiography. The technique was tested in a model, in human saphenous vein specimens, and in long-term experiments in rabbit blood vessels. Eighteen rabbits underwent exploratory surgery, after which the abdominal aorta, inferior vena cave, and the femoral and carotid arteries were coated with tantalum paste. Subsequently, magnification angiograms were performed from one to 14 months later. The wall thickness ranging between 100 and 300 micron was clearly visualized. While no gross inflammatory or foreign body reaction was seen, small granulomata adjacent to the blood vessels were frequently identified. The method described can be valuable in studying the natural history of the atherosclerotic process, particularly the behavior of vascular grafts.

Angiography↗