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Biomedical subjects

Elkan Halpern

Publications and source records attributed to Elkan Halpern.

18 recordsLinked to original sources
PubMed2006

The effect of age, race and gender on preference scores for hypothetical health states.

PURPOSE: Preferences are known to vary by individuals' personal experience with a health state, but variation among respondents' scoring of the same hypothetical state is unproven but relevant to the use of community-perspective preference scores. This research explored the systematic contribution of respondents' age, race and gender to variability in community perspective preferences for hypothetical health states. METHODS: Data from four community samples were pooled for the analysis. Linear regression modeling was used to test for the effect of respondent age, race and gender on preference scores while controlling for health state severity. RESULTS: In this sample of 956 preference scores from 390 individuals across 4 studies, older respondents provided lower preference scores for the same hypothetical health state compared with younger respondents (regression coefficient for 1 year of age = -0.002, p < 0.001), and white individuals provided higher preference scores for the same states compared with non-white individuals (regression coefficient = 0.056, p = 0.014). CONCLUSION: Preferences for hypothetical health states may vary by the age and race of the respondent providing the score. Community-perspective preferences should thus be elicited from large, random samples of the relevant population to ensure variation on these as well as other yet-unidentified characteristics that may affect scores.

Adult↗
PubMed2006

MDCT of the elbow in pediatric patients with posttraumatic elbow effusions.

OBJECTIVE: The purpose of this study was to determine the performance characteristics of MDCT in the detection of fractures in children with posttraumatic elbow effusions and to assess the effect of MDCT findings on clinical management. SUBJECTS AND METHODS: Unenhanced MDCT of the elbow was prospectively performed without sedation on 31 children 20 months to 16 years old who had posttraumatic elbow effusions. Two blinded reviewers independently and in consensus characterized all MDCT scans as positive or negative for the presence of fracture. Level of interobserver agreement was determined with the kappa statistic. Sensitivity, specificity, positive predictive value, and negative predictive value of MDCT for fracture detection were determined for the consensus MDCT interpretations with follow-up radiographs as the reference standard. Patients were treated with casts and instructed to return in 2-3 weeks for clinical and radiographic follow-up unless a change in management was indicated on the basis of MDCT findings. The frequency of alteration of management was determined. RESULTS: Both reviewers detected fractures in 15 (48%) of the patients individually and in 16 (52%) of the patients by consensus. Interobserver agreement for fracture detection with MDCT was excellent (kappa = 0.85). The sensitivity, specificity, positive predictive value, and negative predictive value of MDCT in the detection of fractures were 92%, 79%, 79%, and 92%, respectively. Four (13%) of the children had changes in management based on the MDCT findings. CONCLUSION: MDCT is a sensitive means of evaluating for radiographically occult fractures in children with posttraumatic elbow effusions. It has a high negative predictive value and a high level of interobserver agreement. MDCT findings may lead to alteration of treatment of children with nondisplaced lateral condylar and radial head fractures.

Adolescent↗
PubMed2005

Characterization of atherosclerotic plaques by laser speckle imaging.

BACKGROUND: A method capable of determining atherosclerotic plaque composition and measuring plaque viscoelasticity can provide valuable insight into intrinsic features associated with plaque rupture and can enable the identification of high-risk lesions. In this article, we describe a new optical technique, laser speckle imaging (LSI), that measures an index of plaque viscoelasticity. We evaluate the potential of LSI for characterizing atherosclerotic plaque. METHODS AND RESULTS: Time-varying helium-neon laser speckle images were acquired from 118 aortic plaque specimens from 14 human cadavers under static and deforming conditions (0 to 200 microm/s). Temporal fluctuations in the speckle patterns were quantified by exponential fitting of the normalized cross-correlation of sequential frames in each image series of speckle patterns to obtain the exponential decay time constant, tau. The decorrelation time constants of thin-cap fibroatheromas (TCFA) (tau=47.5+/-19.2 ms) were significantly lower than those of other atherosclerotic lesions (P<0.001), and the sensitivity and specificity of the LSI technique for identifying TCFAs were >90%. Speckle decorrelation time constants demonstrated strong correlation with histological measurements of plaque collagen (R=0.73, P<0.0001), fibrous cap thickness (R=0.87, P<0.0001), and necrotic core area (R=-0.81, P<0.0001). Under deforming conditions (10 to 200 microm/s), tau correlated well with cap thickness in necrotic core fibroatheromas (P>0.05). CONCLUSIONS: The measurement of speckle decorrelation time constant from laser speckle images provides an index of plaque viscoelasticity and facilitates the characterization of plaque type. Our results demonstrate that LSI is a highly sensitive technique for characterizing plaque and identifying thin-cap fibroatheromas.

Analysis of Variance↗
PubMed2005

Prospective comparison of mammography, sonography, and MRI in patients undergoing neoadjuvant chemotherapy for palpable breast cancer.

OBJECTIVE: The objective of our study was to determine the relative accuracy of mammography, sonography, and MRI in predicting residual tumor after neoadjuvant chemotherapy for breast cancer as compared with the gold standards of physical examination and pathology. SUBJECTS AND METHODS: Forty-one women with stage IIB-III palpable breast cancer were prospectively enrolled in a study investigating the effects of sequential single-agent chemotherapy (doxorubicin followed by paclitaxel or vice versa) on tumor imaging. The study cohort consisted of the first 31 patients (age range, 31-65 years; mean, 45 years) who completed the protocol. All underwent physical examination, mammography, sonography, and MRI before and after receiving each neoadjuvant chemotherapeutic drug. Imaging studies were reviewed by two radiologists using conventional lexicons for lesion analysis, and the findings were compared with clinical response and pathology results. RESULTS: Complete, partial, and stable clinical response as defined by clinical examination was seen in 15, 14, and two of the 31 patients, respectively. Agreement rates about the degree of response were 32%, 48%, and 55%, respectively, for mammography, sonography, and MRI compared with clinical evaluation and did not differ statistically. Agreement about the rate of response as measured by clinical examination, mammography, sonography, and MRI compared with the gold standard (pathology) was 19%, 26%, 35%, and 71%, respectively. Of the four, MRI agreed with the gold standard significantly more often (p < 0.002 for all three paired comparisons with MRI). When there was disagreement with the gold standard, none of the four exhibited a significant tendency to either under- or overestimate. CONCLUSION: MRI appears to provide the best correlation with pathology-better than physical examination, mammography, and sonography-in patients undergoing neoadjuvant chemotherapy. However, MRI may overestimate (6%) or underestimate (23%) residual disease in approximately 29% of the patients (95% confidence interval, 14-48%).

Adult↗
PubMed2005

16-MDCT of the posttraumatic pediatric elbow: optimum parameters and associated radiation dose.

OBJECTIVE: Our objective was to investigate a low-radiation-dose protocol for 16-MDCT of the posttraumatic pediatric elbow using z-axis automatic tube-current modulation, based on optimum scanning parameters determined in a porcine fracture model, and to report the radiation dose from this technique in nine children with acute elbow trauma. CONCLUSION: For the posttraumatic pediatric elbow, 16-MDCT using z-axis automatic tube-current modulation was optimal at 100 kVp with a noise index of 20 and a minimum amperage of 25 mA.

Adolescent↗
PubMed2005

Relationships between astrogliosis and 1H MR spectroscopic measures of brain choline/creatine and myo-inositol/creatine in a primate model.

BACKGROUND AND PURPOSE: In vivo 1H MR spectroscopy demonstrates elevated choline (Cho)/creatine (Cr) and myo-inositol (MI)/Cr in many neurologic diseases that has been ascribed to gliosis. We tested the hypotheses that in vivo Cho/Cr and/or MI/Cr levels are correlated with glial fibrillary acidic protein (GFAP) immunostains and that the changes are water-soluble metabolites. METHODS: We performed postmortem 1H MR spectroscopy and GFAP immunohistochemistry in brains from seven rhesus macaques acutely infected with simian immunodeficiency virus (SIV) and in four controls and compared the findings with previous in vivo MR spectroscopic results. Changes in neuropathologic and MR spectroscopic markers after infection and relationships among plasma viral load, GFAP immunostaining results, and ex vivo and in vivo MR spectroscopic measures were statistically evaluated. RESULTS: On GFAP immunostaining and in vivo MR spectroscopy, GFAP, Cho/Cr and MI/Cr were highest near the time of peak plasma viral load at 11 days postinfection (dpi). Immunostains returned to baseline by 14 dpi, whereas Cho/Cr and MI/Cr had different time courses, with the former dropping below baseline and the latter remaining elevated. Viral load and immunostains were significantly correlated. No correlation was found between ex vivo Cho/Cr or MI/Cr and viral load or between metabolite ratios from in vivo and ex vivo MR spectroscopy. CONCLUSION: In acute SIV infection, plasma viral load was significantly correlated with brain GFAP immunostains and in vivo 1H MR spectroscopic Cho/Cr. In vivo changes in Cho/Cr and MI/Cr were principally due to contributions other than those of low-molecular-weight water-soluble metabolites.

Animals↗
PubMed2004

A prospective longitudinal in vivo 1H MR spectroscopy study of the SIV/macaque model of neuroAIDS.

BACKGROUND: The neurological complications of HIV infection remain poorly understood. Clinically, in vivo 1H magnetic resonance spectroscopy (MRS) demonstrates brain injury caused by HIV infection even when the MRI is normal. Our goal was to undertsand the dynamics of cerebral injury by performing a longitudinal in vivo 1H MRS study of the SIV/macaque model of neuroAIDS. RESULTS: Eight rhesus macaques were infected with SIVmac251 and serially imaged with MRI and 1H MRS to terminal AIDS or the endpoint of 2 years. During acute infection, there were stereotypical brain MRS changes, dominated by a significant elevation of the Cho/Cr ratio in the frontal cortex. Subsequently, brain metabolic patterns diverged between animals. There was an elevation of basal ganglia Cho/Cr four weeks post-inoculation in 2 animals that developed SIV encephalitis (p = 0.022). Metabolite ratios averaged across all 8 animals were not significantly different from baseline at any time point after 2 weeks post inoculation. However, linear regression analysis on all 8 animals revealed a positive correlation between a change in frontal lobe Cho/Cr and plasma viral load (P < 0.001, R = 0.80), and a negative correlation between NAA/Cr in the basal ganglia and the plasma viral load (P < 0.02, R = -0.73). No MRI abnormalities were detected at any time. CONCLUSIONS: After infection with SIV, macaque brain metabolism changes in a complex manner that is dependent on brain region, host factors and viral load. An elevation of basal ganglia Cho/Cr 4 weeks after SIV infection may be marker of a propensity to develop SIV encephalitis. Elevations of Cho/Cr, often observed in CNS inflammation, were associated with increased plasma viral load during acute and chronic infection. Evidence of neuronal injury in the basal ganglia was associated with increased plasma viral load in the chronic stage of infection. These observations support the use of drugs capable of controlling the viral replication and trafficking of virus into the CNS, and may help explain the reduction in incidence of HIV-associated dementia in the era of HAART despite the inability of most of those drugs to effectively enter the CNS.

AIDS Dementia Complex↗
PubMed2003

Racial differences in mammographic breast density.

BACKGROUND: African American women have a lower incidence but a higher mortality from breast carcinoma than Caucasians. A proposed explanation for this discrepancy is the decreased efficacy of screening among African American women. Increased breast density in African American women may result in decreased sensitivity of mammography. The purpose of this article is to determine whether there is a difference in mammographic breast density between African American and Caucasian women. METHODS: A series of 769 women were recruited from 5 sites. Mammograms were reviewed centrally by seven reviewers using Breast Imaging Reporting and Data System categories converted to numeric values. The mean mammographic densities for Caucasian, African American, and Latina patients were compared using a two-way analysis of covariance. The mean values for each race were estimated adjusting for the reader as well as for each patient's age and body mass index (BMI). RESULTS: African American women had the lowest mean breast density. The reported density in this group was 2.43, compared with 2.69 among Caucasians and 2.65 among Latina patients. After adjusting for age and BMI as well as the reader, there was still an independent racial effect on breast density (P = 0.0050). CONCLUSIONS: Mammographic breast density was lower in African American women than in Caucasians and Latinas. This discrepancy may be an intrinsic racial difference due to undetermined causes. Factors, such as the growth rate of tumors and the incidence of calcifications, must be studied to confirm that other forces do not have a negative impact on the efficacy of screening mammograms in African American women.

Adult↗
PubMed2003

A simple model of breast carcinoma growth may provide explanations for observations of apparently complex phenomena.

BACKGROUND: There has been great debate regarding the importance of ductal carcinoma in situ (DCIS) in the breast. Autopsy results that demonstrate a much greater number of these lesions compared with the number of invasive carcinomas, and the numbers of deaths from breast carcinoma each year have been cited as evidence that DCIS rarely leads to invasion and death. These analyses have overlooked the fact that, to sustain a rate of detection each year, there would have to be a reservoir of undetected breast carcinomas growing in the population. The authors developed a simple model that makes this clear. In addition, complex phenomena have been suggested to explain why invasive breast disease may grow more rapidly among very young women and more slowly among the very old. A simple model provides some insight that may simplify the explanation of these observations. METHODS: The simple model of breast carcinoma growth assumes that there are three types of breast carcinoma that begin each year in a cohort of women. It assumes that all breast carcinomas begin as DCIS and take 9 years to go from a single cell to an invasive lesion for the slowest growing lesions, 6 years for intermediate growing DCIS lesions, and 3 years for fast-growing DCIS lesions. Furthermore, once an invasive clone forms, the model assumes that it will double in 60 days for fast-growing lesions, 120 days for intermediate growing lesions, and 180 days for slow-growing lesions. Three new tumors begin to grow in each successive year (one of each type). The model uses simple vectors that are defined by the size of the tumors and the time since tumor initiation, and it assumes that all tumors are detected when they reach 2 cm in greatest dimension. The model can be used to show graphically how many undetected tumors (DCIS as well as invasive carcinomas) there may be in the population to sustain the detection of three invasive tumors each year. RESULTS: Using the assumptions described above, the model showed that, by the time the first slow-growing breast carcinoma reaches 2 cm in greatest dimension, there will be 29 other slow-growing tumors that have not reached that size (9 DCIS and 20 smaller invasive carcinomas), 19 moderately growing tumors (6 DCIS and 13 smaller invasive carcinomas), and 9 fast-growing tumors (3 DCIS and 6 smaller invasive carcinomas). This means that, for every three breast tumors that reach 2 cm, the model predicted that there would be another 57 tumors (39 smaller invasive carcinomas and 18 DCIS) that would be undetected "below the surface". The model showed clearly that faster growing tumors would be expected to predominate among the youngest women, because they are the first to "reach the surface"; and, if the number of newly initiated tumors decreases with age, then there will be more of the slowest growing tumors that are left to reach the surface among the oldest women in the population. CONCLUSIONS: Even if the authors' assumptions are incorrect, their model made it clear that, to diagnose several breast carcinomas per 1000 women each year means that there have to be many more undetected carcinomas in the population to sustain the rate of detection. Although the model did not prove that DCIS may become potentially invasive and lethal, it did demonstrate that, even if all of these in situ lesions become invasive and lethal, many more DCIS lesions would have to be expected in the population than the number of invasive carcinomas detected each year and the number of deaths from breast carcinoma each year. Furthermore, the model provided a simple, purely mechanical illustration that may explain the preponderance of faster growing breast carcinomas among very young women and the preponderance of slower growing tumors among elderly women.

Age Factors↗
PubMed2003

Can noise reduction filters improve low-radiation-dose chest CT images? Pilot study.

Effect of noise reduction filters on chest computed tomographic (CT) images acquired with 50% radiation dose reduction was evaluated. Two sets of images were acquired with multi-detector row CT at standard (220-280 mA) and 50% reduced (110-140 mA) tube current at the level of the carina. After postprocessing with six noise reduction filters, images were compared with baseline standard-dose images for noise, sharpness, and contrast in lungs, mediastinum, and chest wall. Quantitative image noise was measured in descending thoracic aorta. Modulation transfer functions were calculated from CT images of 50-microm wire. Noise reduction filters reduced image noise on low-radiation-dose chest CT images, with some compromise in image sharpness and contrast assessed qualitatively, and slightly altered modulation transfer function at higher spatial frequencies.

Aged↗
PubMed2003

Low-dose CT of the abdomen: evaluation of image improvement with use of noise reduction filters pilot study.

A prospective assessment of improvement in image quality at low-radiation-dose computed tomography (CT) of the abdomen by using noise reduction filters was performed. CT images acquired at standard and 50% reduced tube current were processed with six noise reduction filters and evaluated by three radiologists for image noise, sharpness, contrast, and overall image quality in terms of abdominal organ depiction. Quantitative image noise and contrast-to-noise ratio were measured. Baseline low-dose CT images were significantly worse than standard-dose CT images (P <.05). A statistically significant reduction of noise in low-dose images processed with three filters was noted. In conclusion, use of noise reduction filters decreased image noise at low-dose CT.

Aged↗
PubMed2003

Evaluation of simethicone-coated cellulose as a negative oral contrast agent for abdominal CT.

RATIONALE AND OBJECTIVES: Because of the increased clinical use of computed tomography (CT) for imaging the abdominal vasculature and urinary tract, there is a need for negative contrast agents. The authors undertook this study to assess the suitability of simethicone-coated cellulose (SCC), which is approved for use as an oral contrast agent in sonography, for use as a negative oral contrast agent in abdominal CT. MATERIALS AND METHODS: This prospective study involved 40 adult patients scheduled to undergo abdominal CT for the evaluation of hematuria. Prior to scanning, 20 subjects received 800 mL of SCC and 20 received 800 mL of water as an oral contrast agent. Imaging was performed with a multi-detector row helical scanner in two phases, according to the abdominal CT protocol used for hematuria evaluation at the authors' institution. The first, "early" phase began an average of 15 minutes after the ingestion of contrast material; the second, "late" phase began an average of 45 minutes after the ingestion of contrast material. Blinded analysis was performed by three abdominal radiologists separately, using a three-point scale (0 = poor, 1 = acceptable, 2 = excellent) to assess the effectiveness of SCC for marking the proximal, middle, and distal small bowel. Average scores for enhancement with SCC and with water were obtained and compared. Statistical analysis was performed with a Wilcoxon signed-rank test. RESULTS: SCC was assigned higher mean scores than water for enhancement in each segment of the bowel, both on early-phase images (0.8-1.35 for SCC vs 0.6-1.1 for water) and on late-phase images (1.1-1.4 vs 0.81-0.96). Bowel marking with SCC, particularly in the jejunum and ileum, also was rated better than that with water in a high percentage of patients. The differences between the scores for water and for SCC, however, were not statistically significant (P > .05). CONCLUSION: SCC is effective as a negative oral contrast agent for small bowel marking at CT.

Administration, Oral↗
PubMed2003

Multiplanar and 3D imaging of the central airways: comparison of image quality and radiation dose of single-detector row CT and multi-detector row CT at differing tube currents in dogs.

PURPOSE: To compare in an animal model the image quality of multiplanar reformation and three-dimensional (3D) reconstruction images of the central airways by using single-detector row computed tomography (CT) and multi-detector row CT at varied tube currents and to compare radiation dose. MATERIALS AND METHODS: Five dogs each underwent five consecutive helical CT examinations (one single-detector row CT examination at 240 mA and four multi-detector row CT examinations at 240, 120, 40, and 20 mA), with 0.8-second gantry rotation time. Multiplanar reformation and 3D reconstruction images were created from each of the 25 CT acquisitions. The images were randomized and blindly reviewed with consensus agreement by three radiologists who graded image quality by using a five-point scale. In a separate review, the three radiologists independently used a four-point scale to rank the comparative image quality of the multi-detector row CT 3D images, while blinded to specific tube currents. The radiation doses were measured for each type of scan, and the relative radiation dose length products that were normalized to single-detector row CT values were used to compare radiation doses of the various CT techniques. Statistical analysis was performed with the Wilcoxon signed-rank test and the Friedman analysis of variance test. RESULTS: Image quality was consistently ranked higher for multi-detector row CT images than for single-detector row CT images (P =.03). Although there were no distinguishable differences between images obtained with multi-detector row CT at 240, 120, or 40 mA, images obtained with 20 mA were given a significantly (P =.04) lower relative rank (mean, 2.4) than those obtained with higher tube currents (mean, 1.4-1.7). Multi-detector row CT radiation doses were 1.64, 0.82, 0.27, and 0.14 (for 240-, 120-, 40-, and 20-mA multi-detector row CT, respectively) relative to the dose for 240-mA single-detector row CT. CONCLUSION: Multi-detector row CT is superior to single-detector row CT for multiplanar and 3D imaging of the central airways. Substantial dose reductions can be made, while maintaining high image quality.

Animals↗
PubMed2002

Predicting the survival of patients with breast carcinoma using tumor size.

BACKGROUND: Tumor size has long been recognized as the strongest predictor of the outcome of patients with invasive breast carcinoma, although it has not been settled whether the correlation between tumor size and the chance of death is independent of the method of detection, nor is it clear how tumor size at the time of treatment may be translated into a specific expectation of survival. In this report, the authors provide such a method. METHODS: A Kaplan-Meier survival analysis was carried out for a population of 1352 women with invasive breast carcinoma who were treated at the Van Nuys Breast Center between 1966 and 1990, and the data were analyzed together with survival data published by others. RESULTS: The authors found that the survival of patients with invasive breast carcinoma was a direct function of tumor size, independent of the method of detection. The results showed that the correlation between tumor size and survival was well fit by a simple equation, with which survival predictions could be made from information on tumor size. For example, a comparison of three large populations studied over the last 5 decades revealed a marked improvement (approximately 35% absolute) in the survival of patients with invasive breast carcinoma diagnosed on clinical grounds that could be ascribed to a reduction in tumor size. However, the capacity of screening mammography to find smaller tumors remains the best way reduce breast carcinoma deaths, with the potential for adding an additional approximately 20% absolute reduction in breast carcinoma deaths. The mathematic correlation between tumor size and survival is consistent with a biologic mechanism in which lethal distant metastasis occurs by discrete events of spread such that, for every invasive breast carcinoma cell in the primary tumor at the time of surgery, there is approximately a 1-in-1-billion chance that a lethal distant metastasis has formed. CONCLUSIONS: The correlation between tumor size and lethality is well captured by a simple equation that is consistent with breast carcinoma death as the result of discrete events of cellular spread occurring with small but definable probabilities.

Breast Neoplasms↗
PubMed2002

The pattern of breast cancer screening utilization and its consequences.

BACKGROUND: The objective of this study was to describe the pattern of screening utilization and its consequences in terms of tumor size and time of tumor appearance of invasive breast carcinoma among a population of women who were examined at a large service screening/diagnostic program over the last decade. METHODS: Utilization of mammography was assessed from a population of 59,899 women who received 196,891 mammograms at the Massachusetts General Hospital Breast Imaging Division from January 1, 1990 to March 1, 1999, among which 604 invasive breast tumors were found. Two hundred six invasive, clinically detected tumors also were seen during this period among women who had no record of a previous mammogram. Additional information was available on screening of women from March 1, 1999 to June 1, 2001. RESULTS: Fifty percent of the women who used screening did not begin until the age of 50 years, although 25% of the invasive breast tumors were found in women age < 50 years. Relatively few of the women who used screening returned promptly for their annual examinations; by 1.5 years, only 50% had returned. Approximately 25% of the invasive breast tumors were found in women for whom there was no record of a previous screening mammogram, and these tumors were larger (median, 15 mm) than the screen-detected tumors (median, 10 mm). Approximately 30% of the 604 invasive breast tumors in the screening population were found on nonmammographic grounds, and they also were larger (median, 15 mm) than the screen-detected tumors (median, 10 mm). However, only 3% of these 604 tumors were found by nonmammographic criteria within 6 months of the previous negative examination, and only 12% were found within 1 year. By back calculating the likely size of each of these tumors at the time of the negative mammogram, it could be seen that most tumors probably emerged as larger, palpable masses not because they were missed at the previous negative mammogram, because most were too small then to have been detected, but because too much time had been allowed to pass. CONCLUSIONS: Far too many women did not comply with the American Cancer Society recommendation of prompt annual screening from the age of 40 years. Consequently, almost 50% of the invasive tumors emerged as larger and, thus, potentially more lethal, palpable masses.

Breast Neoplasms↗
PubMed2002

Specificity of mammography and US in the evaluation of a palpable abnormality: retrospective review.

PURPOSE: To determine the number of patients who received a diagnosis of breast cancer after having an area of clinical concern at presentation and combined negative mammographic and ultrasonographic (US) findings. MATERIALS AND METHODS: During a 4-year period, 829 patients with a palpable abnormality at presentation and combined negative mammographic and US findings were identified. The number of women who went on to receive a diagnosis of breast cancer was determined retrospectively. The authors searched the breast imaging database and the pathology database, sent a contact letter to the referring physicians, and linked their data to the State Cancer Registry. They also analyzed the breast parenchymal density among all patients who had more than 2 years of follow-up. RESULTS: Of the 829 women, 374 had follow-up information. Two-hundred thirty-three patients had negative imaging findings with more than 2 years of follow-up. The other 141 women were presumed to be cancer free, as they were not identified by the State Cancer Registry. Six (2.6%) of the 233 women had a diagnosis of breast cancer in the area of the palpable abnormality. The six cancers were diagnosed among the 156 women who had radiographically dense breast tissue (Breast Imaging Reporting and Data System category 3 or 4). Among the 77 women with predominantly fatty tissues, no cancers were diagnosed. CONCLUSION: A negative mammographic and US finding of a palpable abnormality does not exclude breast cancer, but the likelihood of breast cancer is low, approximately 2.6%-2.7%. It may be higher if the breast tissues are dense and lower if they are predominantly fatty.

Adult↗
PubMed2002

Pseudoenhancement of simulated renal cysts in a phantom using different multidetector CT scanners.

OBJECTIVE: We undertook this study to determine whether pseudoenhancement of renal cysts occurs on scans obtained with multidetector CT (MDCT) scanners and whether the effect is influenced by scanning parameters. MATERIALS AND METHODS: A kidney phantom with varying attenuation was created to simulate different levels of renal parenchymal enhancement (150 and 250 H). Two water-filled cylinders simulating renal cysts-one with a 5-mm diameter and one with a 15-mm diameter-were suspended in the "kidney." After validating the pseudoenhancement effect produced in our phantom model with a single-detector helical CT scanner, we investigated the effect with matrix array and adaptive array MDCT scanners using detector configurations of 1.25 and 2.5 mm and beam pitches of 0.75:1.0 and 1.5:1.0 at an effective reconstructed slice thickness of approximately 3 mm. Three sets of experiments were performed at each setting, and mean cyst density was measured. Data were statistically analyzed using the Student's t test and multiple logistic regression analysis when appropriate. RESULTS: Although pseudoenhancement was observed with MDCT scanners, the effect was statistically significant only for scans depicting the smaller cyst at a background renal density of 250 H on the matrix array MDCT. Modulation of scanning parameters did not alter these findings. Pseudoenhancement was significantly higher with the matrix array MDCT scanner than with the adaptive array MDCT scanner (p < 0.05). CONCLUSION: In our phantom model, high levels of renal enhancement produced pseudoenhancement in small renal cysts with different models of MDCT scanners, irrespective of pitch or detector configuration.

Humans↗