Improved diagnostic accuracy of breast MRI through combined apparent diffusion coefficients and dynamic contrast-enhanced kinetics.

This study investigated the relationship between apparent diffusion coefficient (ADC) measures and dynamic contrast-enhanced magnetic resonance imaging (MRI) kinetics in breast lesions and evaluated the relative diagnostic value of each quantitative parameter. Seventy-seven women with 100 breast lesions (27 malignant and 73 benign) underwent both dynamic contrast-enhanced MRI and diffusion weighted MRI. Dynamic contrast-enhanced MRI kinetic parameters included peak initial enhancement, predominant delayed kinetic curve type (persistent, plateau, or washout), and worst delayed kinetic curve type (washout > plateau > persistent). Associations between ADC and dynamic contrast-enhanced MRI kinetic parameters and predictions of malignancy were evaluated. Results showed that ADC was significantly associated with predominant curve type (ADC was higher for lesions exhibiting predominantly persistent enhancement compared with those exhibiting predominantly washout or plateau, P = 0.006), but was not significantly associated with peak initial enhancement or worst curve type (P > 0.05). Univariate analysis showed significant differences between benign and malignant lesions in both ADC (P < 0.001) and worst curve (P = 0.003). In multivariate analysis, worst curve type and ADC were significant independent predictors of benign versus malignant outcome and in combination produced the highest area under the receiver operating characteristic curve (0.85 and 0.78 with 5-fold cross validation).

Effect of training with the american college of radiology breast imaging reporting and data system lexicon on mammographic interpretation skills in developing countries.

RATIONALE AND OBJECTIVES: The authors evaluated the effect of training in the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS) lexicon on the interpretive skills of radiologists evaluating screening mammograms in Ukraine. MATERIALS AND METHODS: As part of a program to improve breast cancer detection and treatment in Ukraine, a series of training sessions was given to a group of radiologists across Ukraine to improve their interpretive skills in screening mammography. The training sessions focused on the use of the lexicon and assessment categories developed by the ACR BI-RADS committee. Participants (n = 14) evaluated 30 test screening mammograms before and after the training sessions. The test sets were randomly selected from a larger collection of training sets containing normal, benign, and abnormal mammograms. False-positive, false-negative, true-positive, and true-negative evaluations were determined, and sensitivity, specificity, and positive predictive values were calculated for each participant before and after training. RESULTS: The mean baseline sensitivity, specificity, and positive predictive values were 50%, 77%, and 43%, respectively. Each of these measures of interpretive skills improved significantly after training in the use of the lexicon, to 87%, 89%, and 78% (P < .0001, P < .01, and P < .0001, respectively). CONCLUSION: As the use of mammography spreads throughout developing countries, it is essential to address training and educational needs, as well as equipment needs. The ACR BI-RADS lexicon provides a systematic and efficient method for training radiologists to interpret screening mammograms. Educating radiologists on the use of this lexicon proved an effective way to improve their interpretive skills in screening mammography.

Through-transmission US applied to breast imaging.

RATIONALE AND OBJECTIVES: The purpose of this study was to evaluate the application of a new method of through-transmission ultrasonography (US) to breast imaging. MATERIALS AND METHODS: Through-transmission US was used to image breast tissue in 18 women; 12 had no known lesions, and six had masses, five of which were palpable. Of those with no known lesions, two had implants, and two had mammary duct ectasia. Lesion sizes and locations on the through-transmission sonograms were correlated with findings from conventional imaging to determine successful imaging. Histopathologic findings and lesion size were recorded from pathology reports. Detailed comparative analyses of through-transmission US, conventional x-ray mammography, and conventional US were performed. The following lesion variables were compared: maximum diameter, shape, margins, and internal architecture. RESULTS: Through-transmission US produced images of all masses, some of which were mammographically occult. Comparisons among through-transmission US, mammography, and conventional US showed high correlation in lesion characteristics such as maximum diameter, shape, margins, and internal architecture. For two malignant masses, through-transmission US appeared to be more accurate in assessing tumor extent, compared with mammography and conventional US. CONCLUSION: This new method of through-transmission US produces images of breast tissue in women with a variety of breast types and can be used to detect and characterize a variety of lesions, some of which are mammographically occult.

Effect of age and breast density on screening mammograms with false-positive findings.

OBJECTIVE: The objective of this study was to examine the effect of breast density and age on screening mammograms with false-positive findings. MATERIALS AND METHODS: The study sample was taken from the Washington State Mammography Tumor Registry, which links data from participating radiologists with the Puget Sound Cancer Surveillance System and the Washington State Cancer Registry. Participants (n = 73,247) were women 35 years old and older who underwent screening mammography for which an assessment and a four-category density rating were coded. A total of 46,340 mammograms were sampled to avoid interpreter bias. In this study of false-positive mammograms, only women with no diagnosis of breast cancer within 12 months of the index mammogram were included. Logistic regression was used to estimate the odds ratios of a false-positive mammogram being associated with each category of breast density or age, adjusting for the other factor as a covariate. RESULTS: After controlling for breast density, we found that the risk of a false-positive mammogram was not affected by age (p = 27). However, the trend of increasing risk of a false-positive mammogram with increasing breast density was highly significant (p < .001). Women with extremely dense breast tissue were almost two times more likely to have a false-positive mammogram than were women with fatty breast tissue. This effect persisted after controlling for age. CONCLUSION: Breast density, not age, is an important factor when predicting risk of a false-positive mammogram. Breast density should be considered when educating individual women on the risks and benefits of screening mammography.

Variation in mammographic breast density by time in menstrual cycle among women aged 40-49 years.

BACKGROUND: Mammography is less effective for women aged 40-49 years than for older women, which has led to a call for research to improve the performance of screening mammography for younger women. One factor that may influence the performance of mammography is breast density. Younger women have greater mammographic breast density on average, and increased breast density increases the likelihood of false-negative and false-positive mammograms. We investigated whether breast density varies according to time in a woman's menstrual cycle. METHODS: Premenopausal women aged 40-49 years who were not on exogenous hormones and who had a screening mammogram at a large health maintenance organization during 1996 were studied (n = 2591). Time in the menstrual cycle was based on the woman's self-reported last menstrual bleeding and usual cycle length. RESULTS: A smaller proportion of women had "extremely dense" breasts during the follicular phase of their menstrual cycle (24% for week 1 and 23% for week 2) than during the luteal phase (28% for both weeks 3 and 4) (two-sided P = .04 for the difference in breast density between the phases, adjusted for body mass index). The relationship was stronger for women whose body mass index was less than or equal to the median (two-sided P<.01), the group who have the greatest breast density. CONCLUSIONS/IMPLICATIONS: These findings are consistent with previous evidence suggesting that scheduling a woman's mammogram during the follicular phase (first and second week) of her menstrual cycle instead of during the luteal phase (third and fourth week) may improve the accuracy of mammography for premenopausal women in their forties. Breast tissue is less radiographically dense in the follicular phase than in the luteal phase.

Effect of anesthesia of the chorda tympani nerve on taste perception in humans.

Individuals who have sustained considerable damage to parts of the taste system often fail to experience changes in everyday taste experience. The two halves of the tongue are independently innervated: the chorda tympani (branch of the facial or VIIth cranial nerve) innervating the anterior two-thirds and the glossopharyngeal (IXth cranial nerve) innervating the posterior one-third. Anesthesia of the chorda tympani nerve on one side produced increased taste intensities for some stimuli on the area innervated by the glossopharyngeal nerve on the other side. Because this effect occurs across the midline and taste projects ipsilaterally, the effect must occur in the central nervous system (CNS). This supports Halpern and Nelson's release-of-inhibition hypothesis that the area to which the chorda tympani projects in the CNS must normally inhibit that of the glossopharyngeal nerve. Anesthesia of the chorda tympani abolishes that inhibition and leads to perception of increased taste intensities from areas innervated by the glossopharyngeal nerve.

Trisomy 13 syndrome: prenatal US findings in a review of 33 cases.

PURPOSE: To determine the type and prevalence of prenatal ultrasound (US) findings in fetuses with trisomy 13. MATERIALS AND METHODS: Prenatal US findings in 33 consecutive fetuses with trisomy 13 and in 200 karyotypically normal fetuses were reviewed and compared. RESULTS: One or more abnormalities were found in 30 fetuses (91%). Major anomalies detected by means of US included holoprosencephaly (13 [39%]) or other central nervous system anomalies (19 [58%]), facial anomalies (15 [48%]), and renal (11 [33%]) and cardiac (16 [48%]) defects. Growth retardation was also present in 16 (48%). Echogenic chordae tendineae were seen in 10 (30%), which includes seven (39%) of 18 fetuses examined before 20 menstrual weeks (compared with four [2%] of 200 fetuses in the reference group [P < .001]). Other findings not generally associated with trisomy 13 but present in this series included a large cisterna magna (six [18%]), mild cerebral ventricular dilatation (three [9%]), nuchal thickening or cystic hygroma (seven [21%]), and a hypoplastic left side of the heart (seven [21%]). CONCLUSION: Prenatal US can help detect one or more anomalies in most fetuses with trisomy 13; thus, US finding can indicate whether karyotype should be tested.

Gallstone susceptibility to in vitro fragmentation by a 480-nm pulsed dye laser. Correlation with computed tomography characteristics.

The object of this investigation was to determine gallstone susceptibility to laser lithotripsy and to discover whether this susceptibility is related to the computed tomography (CT) appearance of gallstones. Gallstones collected from surgery were scanned by CT and classified as homogeneously dense (greater than 90 Hounsfield units [HU]), homogeneously faint (30-60 HU), or rimmed. Sixty stones were subjected to laser energy at 20, 40, 60, 80, or 100 mJ. Fracture and fragmentation (all particles less than 2 mm) were assessed in relation to the energy level setting and number of laser pulses delivered. The authors found that a 480-nm, flashlamp-pumped pulsed dye laser can fragment completely all the types of human gallstones that were tested, although there is significant variability in gallstone susceptibility to laser lithotripsy. This susceptibility varies with CT appearance: dense stones require fewer pulses and lower energies for fracture and fragmentation, compared to faint or rimmed stones. The authors anticipate that CT characterization of gallstones may be a clinically useful screening tool before laser lithotripsy.

Impact of environmental stress on the expression of insulin-dependent diabetes mellitus.

To investigate the influence of environmental factors on inherited tendencies, the impact of chronic environmental stress on the expression of a genetically determined autoimmune disease was explored in the bio-breeding (BB) rat, which is an animal model for human autoimmune insulin-dependent diabetes mellitus. Animals assigned at random to the experimental group received a triad of stressors designed to model chronic moderate stress over a 14-week period. Animals from 25 to 130 days of age were weighed and tested for glycosuria twice weekly. Weekly blood sampling was performed on all animals. Diabetes was diagnosed on the basis of weight loss, 2+ glycosuria, and blood glucose levels of 250+ mg/dl. We found that in the BB rat chronic stress significantly increased the incidence of the phenotypic expression of the gene for Type I diabetes. Eighty percent of the male stress and 70% of the female stress animals developed diabetes, compared with 50% in both control groups. Stressed males developed manifest diabetes at the same time as their matched controls, whereas stressed females had significantly delayed onset in relation to controls.