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Biomedical subjects

L Bassett

Publications and source records attributed to L Bassett.

At least 19 recordsLinked to original sources
PubMed2000

Functional speech outcomes after laryngectomy and pharyngolaryngectomy.

OBJECTIVE: To compare and contrast functional speech outcomes of patients having undergone total laryngectomy and pharyngolaryngectomy who use tracheoesophageal speech as their primary mode of communication. DESIGN: Group comparison design. SETTING: Adult acute tertiary care hospital. PATIENTS: Thirty patients who underwent total laryngectomy and 13 who underwent pharyngolaryngectomy with free jejunal interposition reconstruction. All patients used tracheoesophageal speech. INTERVENTION: Group comparisons across measures of speech intelligibility, voice quality, tracheoesophageal speech use, voice satisfaction and levels of perceived voice disability, handicap, and well-being/distress. MAIN OUTCOME MEASURE: The existence of any significant differences between the 2 groups on measures of intelligibility, voice quality, tracheoesophageal speech use, and voice satisfaction and levels of voice disability, handicap, and well-being/distress. RESULTS: Statistical comparisons confirmed reduced functional intelligibility (P<.05), reduced vocal quality (P<.01), and higher levels of disability (P<.05) in the pharyngolaryngectomy group. However, no significant difference was observed between the proportion of patients classified as "successful" tracheoesophageal speech users in either group. Low levels of handicap and high levels of patient well-being were recorded in both groups. CONCLUSION: Despite the perceptual differences in voice quality and intelligibility observed between the 2 groups, tracheoesophageal speech that is functional, effective, and perceived by the patients as satisfactory can be achieved after total laryngectomy and pharyngolaryngectomy with free jejunal interposition reconstruction.

Aged↗
PubMed2000

Decision analysis for the cost effectiveness of sestamibi scintimammography in minimizing unnecessary biopsies.

BACKGROUND: The purpose of this study was to assess if breast cancer screening using sestamibi scintimammography (SSMM) in conjunction with mammography (MM) is cost effective in avoiding biopsies in healthy patients. METHODS: Quantitative decision tree sensitivity analysis was used to compare the conventional MM alone strategy (strategy A) with two decision strategies for screening with SSMM; SSMM after an indeterminate mammogram (strategy B) or SSMM after both a positive and an indeterminate mammogram (strategy C). Cost effectiveness was measured by calculating the expected cost per patient and the average life expectancy per patient for baseline values as well as over a range of values for all of the variables of each strategy. RESULTS: Based on Medicare reimbursement values, strategies B and C showed a cost savings of $9 and $20 per patient respectively as compared to strategy A. This translates into respective savings of $189 and $420 million per year assuming 21 million females undergo screening each year. Strategies B and C did however have a loss of mean life expectancy of 0.000178 and 0.000222 years respectively as compared to strategy A due to interval progression of breast cancer in a small number of women. Strategies B and C significantly lowered the number of biopsies performed on healthy patients in the screening population by 750,063 and 1,557,915 biopsies respectively as compared to strategy A. CONCLUSIONS: These results quantitatively verify the potential utility of using SSMM in avoiding unnecessary biopsies.

Biopsy↗
PubMed1999

A study on the cost effectiveness of sestamibi scintimammography for screening women with dense breasts for breast cancer.

The potential impact of Sestamibi scintimammography (SSMM) on the cost effective management of women with dense breasts is not known. This study addresses this issue quantitatively by examining the impact of SSMM based screening strategies on the approximately 3,000,000 women over 40 with very dense breasts (DY patterns) without palpable masses and who have had one or more prior mammograms, who undergo routine screening each year. Quantitative decision tree sensitivity analysis was used to compare the conventional mammography (MM) strategy (strategy A), which does not subject patients with negative mammograms to any further examination until their next screening, with two decision strategies for screening with SSMM; SSMM after a negative mammogram (strategy B) or SSMM as the only screening test for women already identified as having dense breasts by a previous mammogram (strategy C). Cost effectiveness was measured by calculating the incremental cost effectiveness ratio (ICER) of strategies B and C, which is the cost of achieving an additional year of life in the screening population by choosing a SSMM based decision strategy rather than the conventional strategy. Strategies B and C reduced the number of false negative diagnoses by 62% and 8%, respectively. The ICER was $632,000 and $3.18M per life year for strategy B and C, respectively. To be cost effective, the pre-test probability of cancer in the study population must be greater than 3% for strategy B or the cost of SSMM must be less than $50 for strategy C. These results show the ICER of an SSMM based breast cancer screening strategy in the management of patients with dense breasts is not currently within the range (approximately $50,000 per year life saved) of other commonly performed medical interventions that are considered cost effective.

Adult↗
PubMed1997

Mammography film processor replenishment rate: bromide level monitoring.

The effects of the mammography film processing replenishment rate on contrast and speed are studied sensitometrically. Two experiments studied decreasing replenishment rates in the Kodak RP developer and quantified changes in the developer by measuring bromide ion concentrations. First, values of NaBr concentration from 1.7 to 8.4 g/L, achieved by reducing the replenishment rate, were tested with sensitometry strips. Second, the developer replenishment rate of a high volume dedicated mammography processor was reduced by one-third, to 20 cm3/1560 cm2, so that the NaBr concentration rose from 2.0 to 12.36. Sensitometric results for four film types and patient films were tested for changes from standard values as NaBr concentration was restored to 3.31 g/L. Fifty-five clinical images obtained at 7.3-9.3 NaBr g/L were compared to their matching previous films, with NaBr levels of 2-3 g/L, for contrast and visibility of the skin line. For the range of the NaBr ion from 1.7 to 7 g/L, no significant sensitometric differences were found. Above 7 g/L, different film types had different sensitometric results. From 7.3 to 9.3 NaBr g/L, 47.5% of the clinical films reviewed by four radiologists had less contrast compared to previous films. Dedicated mammography processors with high film volume (i.e., those that do not have excessive oxidation or foreign dye problems) can operate at lower replenishment rates than are currently employed. All common mammography film types are stable at these lower replenishment rates up to 7.0 NaBr g/L.

Biophysical Phenomena↗
PubMed1996

Percutaneous core biopsy of the breast: effect of operator experience and number of samples on diagnostic accuracy.

OBJECTIVE: The purpose of our study was to assess the degree of operator experience and the number of core biopsy samples required to achieve an accurate histologic diagnosis for each of five common mammographically defined lesions, using percutaneous core breast biopsy performed on a dedicated prone biopsy table. SUBJECTS AND METHODS: A prospective multisite study was performed that involved nine institutions (academic and private) with experienced breast radiologists and the use of dedicated prone biopsy table units with digital assistance and standardized protocol. Asymptomatic women evaluated during a 2-year study period were assigned a mammographic diagnosis reported in a manner prescribed by the American College of Radiology Breast Imaging Reporting and Data System lexicon. Mammographic lesions evaluated included masses, masses with calcifications, clustered calcifications, focal asymmetries, and architectural distortions. Where histologic diagnosis was indicated, core biopsy was performed with five individual samples obtained and sequentially analyzed. Two hundred thirty patients had immediate excisional biopsy, the results of which provided the basis for a statistical analysis to compare the accuracy of each sequential core biopsy sample with surgical results. Statistical analysis was also done to ascertain the accuracy of core biopsy diagnosis as a function of operator experience. RESULTS: Trends toward increasing accuracy were observed by increasing the number of core biopsies for each of five types of mammographically defined lesions, especially for clustered calcifications. Statistically significant increased accuracy was observed when the number of biopsies was increased beyond one (p = .003). Trends toward increased accuracy with more experience were observed for all lesions, especially for calcifications. Of the 230 lesions studied with immediate surgical validation, more than 80% of all lesions except clustered calcifications (75%) were diagnosed on the basis of two core biopsies; accuracy after five biopsies was 98% for masses, 91% for calcifications, 100% for masses with calcification, 100% for focal asymmetries, and 86% for architectural distortions. CONCLUSIONS: Accuracy of diagnosis based on the results of percutaneous core breast biopsy improved with an increase in the number of core biopsy samples obtained for any given lesion seen on mammograms and with increased experience in performing the procedure. Five samples yielded an overall diagnostic accuracy of 97%. Familiarity with expected accuracy from this procedure for different mammographic lesions and following increased experience may assist physicians in planning patient management.

Analysis of Variance↗
PubMed1992

Radiation dose.

Explore the source record for details and available documents.

Adult↗
PubMed1989

Magnetic resonance imaging identifies early femoral head ischemic necrosis in patients receiving systemic glucocorticoid therapy.

Ischemic necrosis of bone, a frequent complication of glucocorticoid therapy, can result in disability due to bone collapse and destruction. Some investigators have suggested that core decompression of involved marrow benefits patients with early disease. As radiographs are normal in early disease, identification of patients has been dependent on nonspecific radionuclide imaging or more specific but invasive hemodynamic studies. In order to define a sensitive, noninvasive diagnostic tool, we compared magnetic resonance imaging (MRI) to 99mtechnetium diphosphonate and 99mtechnetium sulfur colloid scintigraphy in 10 consecutive glucocorticoid treated patients with suspected femoral head ischemic necrosis of bone but normal roentgenograms. MRI identified the ischemic necrosis (defined by characteristic radiographic progression or histology) in 13/13 femoral heads. Both scans together identified only 5/13 of the cases. Only 1/20 osteoarthritic femoral heads had MRI patterns similar to those seen in ischemic necrosis of bone. We conclude that MRI is a sensitive and relatively specific method to detect early femoral head ischemic necrosis of bone.

Adult↗
PubMed1987

Anatomic correlation of cadaver cryomicrotomy with magnetic resonance imaging.

The performance of frozen sections of a thickness varying between 5 and 50 microns in fresh undecalcified cadaveric human specimens was perfected in Sweden by one of the authors in 1983. This technique makes it possible to obtain anatomic images of high definition which were correlated with MRI sections made at intervals of 20 microns.

Cadaver↗
PubMed1986

Solenoid surface coils in magnetic resonance imaging.

A nonplanar solenoidal surface radiofrequency coil is used as a receiver with a conventional transmitter coil in a magnetic resonance imaging system. The improved signal-to-noise ratio, compared with that of conventional fixed saddle or solenoid receiver coils, permits higher resolution imaging and thinner image sections. In addition, the problem of signal dropoff that occurs in deep structures with planar and other noncircumferential surface coils is eliminated. Solenoid surface coils are particularly useful in imaging deep structures in anatomic regions that do not fit standard head and body coils, such as the neck, knees, and other smaller body parts.

Adult↗
PubMed1986

The grid radiograph. A simple technique for consistent high-resolution visualization of the hip.

The grid radiograph, a new technique for radiographic evaluation of total hip replacements, ensures reproducible positioning of the hip and the x-ray beam. When this method was used, the images of stable acetabular and femoral components on one radiograph could be superimposed perfectly on the images of these components on subsequent radiographs. Subtle shifts in the positions of the components, such as tilting of the femoral surface replacement, subsidence of the femoral component, or migration of the acetabular component, were detected. When used with high-contrast radiographic technique and film, the implant-bone interfaces were depicted better by this method than by others. Grid radiographs can be used for detailed prospective evaluation of total hip replacements and are of practical value in counseling patients about the probable durability of the replacement.

Acetabulum↗